Copyright 2014-2018 The Khronos Group Inc.
This Specification is protected by copyright laws and contains material proprietary to Khronos. Except as described by these terms, it or any components may not be reproduced, republished, distributed, transmitted, displayed, broadcast or otherwise exploited in any manner without the express prior written permission of Khronos. Khronos grants a conditional copyright license to use and reproduce the unmodified Specification for any purpose, without fee or royalty, EXCEPT no licenses to any patent, trademark or other intellectual property rights are granted under these terms.
Khronos makes no, and expressly disclaims any, representations or warranties, express or implied, regarding this Specification, including, without limitation: merchantability, fitness for a particular purpose, non-infringement of any intellectual property, correctness, accuracy, completeness, timeliness, and reliability. Under no circumstances will Khronos, or any of its Promoters, Contributors or Members, or their respective partners, officers, directors, employees, agents or representatives be liable for any damages, whether direct, indirect, special or consequential damages for lost revenues, lost profits, or otherwise, arising from or in connection with these materials.
This Specification has been created under the Khronos Intellectual Property Rights Policy, which is Attachment A of the Khronos Group Membership Agreement available at www.khronos.org/files/member_agreement.pdf, and which defines the terms 'Scope', 'Compliant Portion', and 'Necessary Patent Claims'. Parties desiring to implement the Specification and make use of Khronos trademarks in relation to that implementation, and receive reciprocal patent license protection under the Khronos Intellectual Property Rights Policy must become Adopters and confirm the implementation as conformant under the process defined by Khronos for this Specification; see https://www.khronos.org/adopters.
This Specification contains substantially unmodified functionality from, and is a successor to, Khronos specifications including OpenGL, OpenGL ES and OpenCL.
Some parts of this Specification are purely informative and so are EXCLUDED from the Scope of this Specification. The Document Conventions section of the Introduction defines how these parts of the Specification are identified.
Where this Specification uses technical terminology, defined in the Glossary or otherwise, that refer to enabling technologies that are not expressly set forth in this Specification, those enabling technologies are EXCLUDED from the Scope of this Specification. For clarity, enabling technologies not disclosed with particularity in this Specification (e.g. semiconductor manufacturing technology, hardware architecture, processor architecture or microarchitecture, memory architecture, compiler technology, object oriented technology, basic operating system technology, compression technology, algorithms, and so on) are NOT to be considered expressly set forth; only those application program interfaces and data structures disclosed with particularity are included in the Scope of this Specification.
For purposes of the Khronos Intellectual Property Rights Policy as it relates to the definition of Necessary Patent Claims, all recommended or optional features, behaviors and functionality set forth in this Specification, if implemented, are considered to be included as Compliant Portions.
Where this Specification includes normative references to external documents, only the specifically identified sections of those external documents are INCLUDED in the Scope of this Specification. If not created by Khronos, those external documents may contain contributions from non-members of Khronos not covered by the Khronos Intellectual Property Rights Policy.
Vulkan is a registered trademark, and Khronos is a trademark of The Khronos Group Inc. ASTC is a trademark of ARM Holdings PLC; OpenCL is a trademark of Apple Inc.; and OpenGL is a registered trademark of Silicon Graphics International, all used under license by Khronos. All other product names, trademarks, and/or company names are used solely for identification and belong to their respective owners.
1. Introduction
This document, referred to as the “Vulkan Specification” or just the “Specification” hereafter, describes the Vulkan Application Programming Interface (API). Vulkan is a C99 API designed for explicit control of low-level graphics and compute functionality.
The canonical version of the Specification is available in the official Vulkan Registry (http://www.khronos.org/registry/vulkan/). The source files used to generate the Vulkan specification are stored in the Vulkan Documentation Repository (https://github.com/KhronosGroup/Vulkan-Docs). The source repository additionally has a public issue tracker and allows the submission of pull requests that improve the specification.
1.1. Document Conventions
The Vulkan specification is intended for use by both implementors of the API and application developers seeking to make use of the API, forming a contract between these parties. Specification text may address either party; typically the intended audience can be inferred from context, though some sections are defined to address only one of these parties. (For example, Valid Usage sections only address application developers). Any requirements, prohibitions, recommendations or options defined by normative terminology are imposed only on the audience of that text.
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Note
Structure and enumerated types defined in extensions that were promoted to core in Vulkan 1.1 are now defined in terms of the equivalent Vulkan 1.1 interfaces. This affects the Vulkan Specification, the Vulkan header files, and the corresponding XML Registry. |
1.1.1. Normative Terminology
Within this specification, the key words must, required, should, recommended, may, and optional are to be interpreted as described in RFC 2119 - Key words for use in RFCs to Indicate Requirement Levels (http://www.ietf.org/rfc/rfc2119.txt). These key words are highlighted in the specification for clarity. In text addressing application developers, their use expresses requirements that apply to application behavior. In text addressing implementors, their use expresses requirements that apply to implementations.
In text addressing application developers, the additional key words can and cannot are to be interpreted as describing the capabilities of an application, as follows:
- can
-
This word means that the application is able to perform the action described.
- cannot
-
This word means that the API and/or the execution environment provide no mechanism through which the application can express or accomplish the action described.
These key words are never used in text addressing implementors.
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Note
There is an important distinction between cannot and must not, as used in this Specification. Cannot means something the application literally is unable to express or accomplish through the API, while must not means something that the application is capable of expressing through the API, but that the consequences of doing so are undefined and potentially unrecoverable for the implementation. |
Unless otherwise noted in the section heading, all sections and appendices in this document are normative.
1.1.2. Technical Terminology
The Vulkan Specification makes use of common engineering and graphics terms such as Pipeline, Shader, and Host to identify and describe Vulkan API constructs and their attributes, states, and behaviors. The Glossary defines the basic meanings of these terms in the context of the Specification. The Specification text provides fuller definitions of the terms and may elaborate, extend, or clarify the Glossary definitions. When a term defined in the Glossary is used in normative language within the Specification, the definitions within the Specification govern and supersede any meanings the terms may have in other technical contexts (i.e. outside the Specification).
1.1.3. Normative References
References to external documents are considered normative references if the Specification uses any of the normative terms defined in Normative Terminology to refer to them or their requirements, either as a whole or in part.
The following documents are referenced by normative sections of the specification:
IEEE Standard for Floating-Point Arithmetic, IEEE Std 754-2008, http://dx.doi.org/10.1109/IEEESTD.2008.4610935, August, 2008.
A. Garrard, Khronos Data Format Specification, version 1.2, https://www.khronos.org/registry/DataFormat/specs/1.2/dataformat.1.2.html, September, 2017.
J. Kessenich, SPIR-V Extended Instructions for GLSL, Version 1.00, https://www.khronos.org/registry/spir-v/, February 10, 2016.
J. Kessenich and B. Ouriel, The Khronos SPIR-V Specification, Version 1.00, https://www.khronos.org/registry/spir-v/, February 10, 2016.
J. Leech and T. Hector, Vulkan Documentation and Extensions: Procedures and Conventions, https://www.khronos.org/registry/vulkan/, July 11, 2016
Vulkan Loader Specification and Architecture Overview, https://github.com/KhronosGroup/Vulkan-LoaderAndValidationLayers/blob/master/loader/LoaderAndLayerInterface.md, August, 2016.
2. Fundamentals
This chapter introduces fundamental concepts including the Vulkan architecture and execution model, API syntax, queues, pipeline configurations, numeric representation, state and state queries, and the different types of objects and shaders. It provides a framework for interpreting more specific descriptions of commands and behavior in the remainder of the Specification.
2.1. Host and Device Environment
The Vulkan Specification assumes and requires: the following properties of the host environment with respect to Vulkan implementations:
-
The host must have runtime support for 8, 16, 32 and 64-bit signed and unsigned twos-complement integers, all addressable at the granularity of their size in bytes.
-
The host must have runtime support for 32- and 64-bit floating-point types satisfying the range and precision constraints in the Floating Point Computation section.
-
The representation and endianness of these types on the host must match the representation and endianness of the same types on every physical device supported.
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Note
Since a variety of data types and structures in Vulkan may be accessible by both host and physical device operations, the implementation should be able to access such data efficiently in both paths in order to facilitate writing portable and performant applications. |
2.2. Execution Model
This section outlines the execution model of a Vulkan system.
Vulkan exposes one or more devices, each of which exposes one or more queues which may process work asynchronously to one another. The set of queues supported by a device is partitioned into families. Each family supports one or more types of functionality and may contain multiple queues with similar characteristics. Queues within a single family are considered compatible with one another, and work produced for a family of queues can be executed on any queue within that family. This Specification defines four types of functionality that queues may support: graphics, compute, transfer, and sparse memory management.
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Note
A single device may report multiple similar queue families rather than, or as well as, reporting multiple members of one or more of those families. This indicates that while members of those families have similar capabilities, they are not directly compatible with one another. |
Device memory is explicitly managed by the application. Each device may advertise one or more heaps, representing different areas of memory. Memory heaps are either device local or host local, but are always visible to the device. Further detail about memory heaps is exposed via memory types available on that heap. Examples of memory areas that may be available on an implementation include:
-
device local is memory that is physically connected to the device.
-
device local, host visible is device local memory that is visible to the host.
-
host local, host visible is memory that is local to the host and visible to the device and host.
On other architectures, there may only be a single heap that can be used for any purpose.
A Vulkan application controls a set of devices through the submission of command buffers which have recorded device commands issued via Vulkan library calls. The content of command buffers is specific to the underlying implementation and is opaque to the application. Once constructed, a command buffer can be submitted once or many times to a queue for execution. Multiple command buffers can be built in parallel by employing multiple threads within the application.
Command buffers submitted to different queues may execute in parallel or even out of order with respect to one another. Command buffers submitted to a single queue respect submission order, as described further in synchronization chapter. Command buffer execution by the device is also asynchronous to host execution. Once a command buffer is submitted to a queue, control may return to the application immediately. Synchronization between the device and host, and between different queues is the responsibility of the application.
2.2.1. Queue Operation
Vulkan queues provide an interface to the execution engines of a device. Commands for these execution engines are recorded into command buffers ahead of execution time. These command buffers are then submitted to queues with a queue submission command for execution in a number of batches. Once submitted to a queue, these commands will begin and complete execution without further application intervention, though the order of this execution is dependent on a number of implicit and explicit ordering constraints.
Work is submitted to queues using queue submission commands that typically
take the form vkQueue* (e.g. vkQueueSubmit,
vkQueueBindSparse), and optionally take a list of semaphores upon
which to wait before work begins and a list of semaphores to signal once
work has completed.
The work itself, as well as signaling and waiting on the semaphores are all
queue operations.
Queue operations on different queues have no implicit ordering constraints, and may execute in any order. Explicit ordering constraints between queues can be expressed with semaphores and fences.
Command buffer submissions to a single queue respect submission order and other implicit ordering guarantees, but otherwise may overlap or execute out of order. Other types of batches and queue submissions against a single queue (e.g. sparse memory binding) have no implicit ordering constraints with any other queue submission or batch. Additional explicit ordering constraints between queue submissions and individual batches can be expressed with semaphores and fences.
Before a fence or semaphore is signaled, it is guaranteed that any previously submitted queue operations have completed execution, and that memory writes from those queue operations are available to future queue operations. Waiting on a signaled semaphore or fence guarantees that previous writes that are available are also visible to subsequent commands.
Command buffer boundaries, both between primary command buffers of the same or different batches or submissions as well as between primary and secondary command buffers, do not introduce any additional ordering constraints. In other words, submitting the set of command buffers (which can include executing secondary command buffers) between any semaphore or fence operations execute the recorded commands as if they had all been recorded into a single primary command buffer, except that the current state is reset on each boundary. Explicit ordering constraints can be expressed with explicit synchronization primitives.
There are a few implicit ordering guarantees between commands within a command buffer, but only covering a subset of execution. Additional explicit ordering constraints can be expressed with the various explicit synchronization primitives.
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Note
Implementations have significant freedom to overlap execution of work submitted to a queue, and this is common due to deep pipelining and parallelism in Vulkan devices. |
Commands recorded in command buffers either perform actions (draw, dispatch, clear, copy, query/timestamp operations, begin/end subpass operations), set state (bind pipelines, descriptor sets, and buffers, set dynamic state, push constants, set render pass/subpass state), or perform synchronization (set/wait events, pipeline barrier, render pass/subpass dependencies). Some commands perform more than one of these tasks. State setting commands update the current state of the command buffer. Some commands that perform actions (e.g. draw/dispatch) do so based on the current state set cumulatively since the start of the command buffer. The work involved in performing action commands is often allowed to overlap or to be reordered, but doing so must not alter the state to be used by each action command. In general, action commands are those commands that alter framebuffer attachments, read/write buffer or image memory, or write to query pools.
Synchronization commands introduce explicit execution and memory dependencies between two sets of action commands, where the second set of commands depends on the first set of commands. These dependencies enforce that both the execution of certain pipeline stages in the later set occur after the execution of certain stages in the source set, and that the effects of memory accesses performed by certain pipeline stages occur in order and are visible to each other. When not enforced by an explicit dependency or implicit ordering guarantees, action commands may overlap execution or execute out of order, and may not see the side effects of each other’s memory accesses.
The device executes queue operations asynchronously with respect to the host. Control is returned to an application immediately following command buffer submission to a queue. The application must synchronize work between the host and device as needed.
2.3. Object Model
The devices, queues, and other entities in Vulkan are represented by Vulkan objects. At the API level, all objects are referred to by handles. There are two classes of handles, dispatchable and non-dispatchable. Dispatchable handle types are a pointer to an opaque type. This pointer may be used by layers as part of intercepting API commands, and thus each API command takes a dispatchable type as its first parameter. Each object of a dispatchable type must have a unique handle value during its lifetime.
Non-dispatchable handle types are a 64-bit integer type whose meaning is implementation-dependent, and may encode object information directly in the handle rather than acting as a reference to an underlying object. Objects of a non-dispatchable type may not have unique handle values within a type or across types. If handle values are not unique, then destroying one such handle must not cause identical handles of other types to become invalid, and must not cause identical handles of the same type to become invalid if that handle value has been created more times than it has been destroyed.
All objects created or allocated from a VkDevice (i.e. with a
VkDevice as the first parameter) are private to that device, and must
not be used on other devices.
2.3.1. Object Lifetime
Objects are created or allocated by vkCreate* and vkAllocate*
commands, respectively.
Once an object is created or allocated, its “structure” is considered to
be immutable, though the contents of certain object types is still free to
change.
Objects are destroyed or freed by vkDestroy* and vkFree*
commands, respectively.
Objects that are allocated (rather than created) take resources from an existing pool object or memory heap, and when freed return resources to that pool or heap. While object creation and destruction are generally expected to be low-frequency occurrences during runtime, allocating and freeing objects can occur at high frequency. Pool objects help accommodate improved performance of the allocations and frees.
It is an application’s responsibility to track the lifetime of Vulkan objects, and not to destroy them while they are still in use.
The ownership of application-owned memory is immediately acquired by any Vulkan command it is passed into. Ownership of such memory must be released back to the application at the end of the duration of the command, so that the application can alter or free this memory as soon as all the commands that acquired it have returned.
The following object types are consumed when they are passed into a Vulkan command and not further accessed by the objects they are used to create. They must not be destroyed in the duration of any API command they are passed into:
-
VkShaderModule -
VkPipelineCache -
VkValidationCacheEXT
A VkRenderPass object passed as a parameter to create another object
is not further accessed by that object after the duration of the command it
is passed into.
A VkRenderPass used in a command buffer follows the rules described
below.
A VkPipelineLayout object must not be destroyed while any command
buffer that uses it is in the recording state.
VkDescriptorSetLayout objects may be accessed by commands that
operate on descriptor sets allocated using that layout, and those descriptor
sets must not be updated with vkUpdateDescriptorSets after the
descriptor set layout has been destroyed.
Otherwise, a VkDescriptorSetLayout object passed as a parameter to
create another object is not further accessed by that object after the
duration of the command it is passed into.
The application must not destroy any other type of Vulkan object until all uses of that object by the device (such as via command buffer execution) have completed.
The following Vulkan objects must not be destroyed while any command buffers using the object are in the pending state:
-
VkEvent -
VkQueryPool -
VkBuffer -
VkBufferView -
VkImage -
VkImageView -
VkPipeline -
VkSampler -
VkSamplerYcbcrConversion -
VkDescriptorPool -
VkFramebuffer -
VkRenderPass -
VkCommandBuffer -
VkCommandPool -
VkDeviceMemory -
VkDescriptorSet -
VkObjectTableNVX -
VkIndirectCommandsLayout
Destroying these objects will move any command buffers that are in the recording or executable state, and are using those objects, to the invalid state.
The following Vulkan objects must not be destroyed while any queue is executing commands that use the object:
-
VkFence -
VkSemaphore -
VkCommandBuffer -
VkCommandPool
In general, objects can be destroyed or freed in any order, even if the object being freed is involved in the use of another object (e.g. use of a resource in a view, use of a view in a descriptor set, use of an object in a command buffer, binding of a memory allocation to a resource), as long as any object that uses the freed object is not further used in any way except to be destroyed or to be reset in such a way that it no longer uses the other object (such as resetting a command buffer). If the object has been reset, then it can be used as if it never used the freed object. An exception to this is when there is a parent/child relationship between objects. In this case, the application must not destroy a parent object before its children, except when the parent is explicitly defined to free its children when it is destroyed (e.g. for pool objects, as defined below).
VkCommandPool objects are parents of VkCommandBuffer objects.
VkDescriptorPool objects are parents of VkDescriptorSet objects.
VkDevice objects are parents of many object types (all that take a
VkDevice as a parameter to their creation).
The following Vulkan objects have specific restrictions for when they can be destroyed:
-
VkQueueobjects cannot be explicitly destroyed. Instead, they are implicitly destroyed when theVkDeviceobject they are retrieved from is destroyed. -
Destroying a pool object implicitly frees all objects allocated from that pool. Specifically, destroying
VkCommandPoolfrees allVkCommandBufferobjects that were allocated from it, and destroyingVkDescriptorPoolfrees allVkDescriptorSetobjects that were allocated from it. -
VkDeviceobjects can be destroyed when allVkQueueobjects retrieved from them are idle, and all objects created from them have been destroyed. This includes the following objects:-
VkFence -
VkSemaphore -
VkEvent -
VkQueryPool -
VkBuffer -
VkBufferView -
VkImage -
VkImageView -
VkShaderModule -
VkPipelineCache -
VkPipeline -
VkPipelineLayout -
VkSampler -
VkSamplerYcbcrConversion -
VkDescriptorSetLayout -
VkDescriptorPool -
VkFramebuffer -
VkRenderPass -
VkCommandPool -
VkCommandBuffer -
VkDeviceMemory
-
-
VkValidationCacheEXT -
VkPhysicalDeviceobjects cannot be explicitly destroyed. Instead, they are implicitly destroyed when theVkInstanceobject they are retrieved from is destroyed. -
VkInstanceobjects can be destroyed once allVkDeviceobjects created from any of itsVkPhysicalDeviceobjects have been destroyed.
2.3.2. External Object Handles
As defined above, the scope of object handles created or allocated from a
VkDevice is limited to that logical device.
Objects which are not in scope are said to be external.
To bring an external object into scope, an external handle must be exported
from the object in the source scope and imported into the destination scope.
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Note
The scope of external handles and their associated resources may vary according to their type, but they can generally be shared across process and API boundaries. |
2.4. Application Binary Interface
The mechanism by which Vulkan is made available to applications is platform- or implementation- defined. On many platforms the C interface described in this Specification is provided by a shared library. Since shared libraries can be changed independently of the applications that use them, they present particular compatibility challenges, and this Specification places some requirements on them.
Shared library implementations must use the default Application Binary
Interface (ABI) of the standard C compiler for the platform, or provide
customized API headers that cause application code to use the
implementation’s non-default ABI.
An ABI in this context means the size, alignment, and layout of C data
types; the procedure calling convention; and the naming convention for
shared library symbols corresponding to C functions.
Customizing the calling convention for a platform is usually accomplished by
defining calling
convention macros appropriately in vk_platform.h.
On platforms where Vulkan is provided as a shared library, library symbols beginning with “vk” and followed by a digit or uppercase letter are reserved for use by the implementation. Applications which use Vulkan must not provide definitions of these symbols. This allows the Vulkan shared library to be updated with additional symbols for new API versions or extensions without causing symbol conflicts with existing applications.
Shared library implementations should provide library symbols for commands in the highest version of this Specification they support, and for Window System Integration extensions relevant to the platform. They may also provide library symbols for commands defined by additional extensions.
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Note
These requirements and recommendations are intended to allow implementors to take advantage of platform-specific conventions for SDKs, ABIs, library versioning mechanisms, etc. while still minimizing the code changes necessary to port applications or libraries between platforms. Platform vendors, or providers of the de facto standard Vulkan shared library for a platform, are encouraged to document what symbols the shared library provides and how it will be versioned when new symbols are added. Applications should only rely on shared library symbols for commands in the minimum core version required by the application. vkGetInstanceProcAddr and vkGetDeviceProcAddr should be used to obtain function pointers for commands in core versions beyond the application’s minimum required version. |
2.5. Command Syntax and Duration
The Specification describes Vulkan commands as functions or procedures using C99 syntax. Language bindings for other languages such as C++ and JavaScript may allow for stricter parameter passing, or object-oriented interfaces.
Vulkan uses the standard C types for the base type of scalar parameters
(e.g. types from <stdint.h>), with exceptions described below, or
elsewhere in the text when appropriate:
VkBool32 represents boolean True and False values, since C does
not have a sufficiently portable built-in boolean type:
typedef uint32_t VkBool32;
VK_TRUE represents a boolean True (integer 1) value, and
VK_FALSE a boolean False (integer 0) value.
All values returned from a Vulkan implementation in a VkBool32 will
be either VK_TRUE or VK_FALSE.
Applications must not pass any other values than VK_TRUE or
VK_FALSE into a Vulkan implementation where a VkBool32 is
expected.
VkDeviceSize represents device memory size and offset values:
typedef uint64_t VkDeviceSize;
Commands that create Vulkan objects are of the form vkCreate* and take
Vk*CreateInfo structures with the parameters needed to create the
object.
These Vulkan objects are destroyed with commands of the form
vkDestroy*.
The last in-parameter to each command that creates or destroys a Vulkan
object is pAllocator.
The pAllocator parameter can be set to a non-NULL value such that
allocations for the given object are delegated to an application provided
callback; refer to the Memory Allocation chapter for
further details.
Commands that allocate Vulkan objects owned by pool objects are of the form
vkAllocate*, and take Vk*AllocateInfo structures.
These Vulkan objects are freed with commands of the form vkFree*.
These objects do not take allocators; if host memory is needed, they will
use the allocator that was specified when their parent pool was created.
Commands are recorded into a command buffer by calling API commands of the
form vkCmd*.
Each such command may have different restrictions on where it can be used:
in a primary and/or secondary command buffer, inside and/or outside a render
pass, and in one or more of the supported queue types.
These restrictions are documented together with the definition of each such
command.
The duration of a Vulkan command refers to the interval between calling the command and its return to the caller.
2.5.1. Lifetime of Retrieved Results
Information is retrieved from the implementation with commands of the form
vkGet* and vkEnumerate*.
Unless otherwise specified for an individual command, the results are invariant; that is, they will remain unchanged when retrieved again by calling the same command with the same parameters, so long as those parameters themselves all remain valid.
2.6. Threading Behavior
Vulkan is intended to provide scalable performance when used on multiple host threads. All commands support being called concurrently from multiple threads, but certain parameters, or components of parameters are defined to be externally synchronized. This means that the caller must guarantee that no more than one thread is using such a parameter at a given time.
More precisely, Vulkan commands use simple stores to update the state of Vulkan objects. A parameter declared as externally synchronized may have its contents updated at any time during the host execution of the command. If two commands operate on the same object and at least one of the commands declares the object to be externally synchronized, then the caller must guarantee not only that the commands do not execute simultaneously, but also that the two commands are separated by an appropriate memory barrier (if needed).
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Note
Memory barriers are particularly relevant for hosts based on the ARM CPU architecture, which is more weakly ordered than many developers are accustomed to from x86/x64 programming. Fortunately, most higher-level synchronization primitives (like the pthread library) perform memory barriers as a part of mutual exclusion, so mutexing Vulkan objects via these primitives will have the desired effect. |
Similarly the application must avoid any potential data hazard of
application-owned memory that has its
ownership temporarily acquired
by a Vulkan command.
While the ownership of application-owned memory remains acquired by a
command the implementation may read the memory at any point, and it may
write non-const qualified memory at any point.
Parameters referring to non-const qualified application-owned memory
are not marked explicitly as externally synchronized in the Specification.
Many object types are immutable, meaning the objects cannot change once
they have been created.
These types of objects never need external synchronization, except that they
must not be destroyed while they are in use on another thread.
In certain special cases mutable object parameters are internally
synchronized, making external synchronization unnecessary.
One example of this is the use of a VkPipelineCache in
vkCreateGraphicsPipelines and vkCreateComputePipelines, where
external synchronization around such a heavyweight command would be
impractical.
The implementation must internally synchronize the cache in this example,
and may be able to do so in the form of a much finer-grained mutex around
the command.
Any command parameters that are not labeled as externally synchronized are
either not mutated by the command or are internally synchronized.
Additionally, certain objects related to a command’s parameters (e.g.
command pools and descriptor pools) may be affected by a command, and must
also be externally synchronized.
These implicit parameters are documented as described below.
Parameters of commands that are externally synchronized are listed below.
There are also a few instances where a command can take in a user allocated list whose contents are externally synchronized parameters. In these cases, the caller must guarantee that at most one thread is using a given element within the list at a given time. These parameters are listed below.
In addition, there are some implicit parameters that need to be externally
synchronized.
For example, all commandBuffer parameters that need to be externally
synchronized imply that the commandPool that was passed in when
creating that command buffer also needs to be externally synchronized.
The implicit parameters and their associated object are listed below.
2.7. Errors
Vulkan is a layered API. The lowest layer is the core Vulkan layer, as defined by this Specification. The application can use additional layers above the core for debugging, validation, and other purposes.
One of the core principles of Vulkan is that building and submitting command buffers should be highly efficient. Thus error checking and validation of state in the core layer is minimal, although more rigorous validation can be enabled through the use of layers.
The core layer assumes applications are using the API correctly. Except as documented elsewhere in the Specification, the behavior of the core layer to an application using the API incorrectly is undefined, and may include program termination. However, implementations must ensure that incorrect usage by an application does not affect the integrity of the operating system, the Vulkan implementation, or other Vulkan client applications in the system. In particular, any guarantees made by an operating system about whether memory from one process can be visible to another process or not must not be violated by a Vulkan implementation for any memory allocation. Vulkan implementations are not required to make additional security or integrity guarantees beyond those provided by the OS unless explicitly directed by the application’s use of a particular feature or extension (e.g. via robust buffer access).
|
Note
For instance, if an operating system guarantees that data in all its memory allocations are set to zero when newly allocated, the Vulkan implementation must make the same guarantees for any allocations it controls (e.g. VkDeviceMemory). |
Applications can request stronger robustness guarantees by enabling the
robustBufferAccess feature as described in Features, Limits, and Formats.
Validation of correct API usage is left to validation layers. Applications should be developed with validation layers enabled, to help catch and eliminate errors. Once validated, released applications should not enable validation layers by default.
2.7.1. Valid Usage
Valid usage defines a set of conditions which must be met in order to achieve well-defined run-time behavior in an application. These conditions depend only on Vulkan state, and the parameters or objects whose usage is constrained by the condition.
Some valid usage conditions have dependencies on run-time limits or feature availability. It is possible to validate these conditions against Vulkan’s minimum supported values for these limits and features, or some subset of other known values.
Valid usage conditions do not cover conditions where well-defined behavior (including returning an error code) exists.
Valid usage conditions should apply to the command or structure where complete information about the condition would be known during execution of an application. This is such that a validation layer or linter can be written directly against these statements at the point they are specified.
|
Note
This does lead to some non-obvious places for valid usage statements. For instance, the valid values for a structure might depend on a separate value in the calling command. In this case, the structure itself will not reference this valid usage as it is impossible to determine validity from the structure that it is invalid - instead this valid usage would be attached to the calling command. Another example is draw state - the state setters are independent, and can cause a legitimately invalid state configuration between draw calls; so the valid usage statements are attached to the place where all state needs to be valid - at the draw command. |
Valid usage conditions are described in a block labelled “Valid Usage” following each command or structure they apply to.
2.7.2. Implicit Valid Usage
Some valid usage conditions apply to all commands and structures in the API, unless explicitly denoted otherwise for a specific command or structure. These conditions are considered implicit, and are described in a block labelled “Valid Usage (Implicit)” following each command or structure they apply to. Implicit valid usage conditions are described in detail below.
Valid Usage for Object Handles
Any input parameter to a command that is an object handle must be a valid object handle, unless otherwise specified. An object handle is valid if:
-
It has been created or allocated by a previous, successful call to the API. Such calls are noted in the Specification.
-
It has not been deleted or freed by a previous call to the API. Such calls are noted in the Specification.
-
Any objects used by that object, either as part of creation or execution, must also be valid.
The reserved values VK_NULL_HANDLE and NULL can be used in place of
valid non-dispatchable handles and dispatchable handles, respectively, when
explicitly called out in the Specification.
Any command that creates an object successfully must not return these
values.
It is valid to pass these values to vkDestroy* or vkFree*
commands, which will silently ignore these values.
Valid Usage for Pointers
Any parameter that is a pointer must be a valid pointer only if it is explicitly called out by a Valid Usage statement.
A pointer is “valid” if it points at memory containing values of the number and type(s) expected by the command, and all fundamental types accessed through the pointer (e.g. as elements of an array or as members of a structure) satisfy the alignment requirements of the host processor.
Valid Usage for Strings
Any parameter that is a pointer to char must be a finite sequence of
values terminated by a null character, or if explicitly called out in the
Specification, can be NULL.
Valid Usage for Enumerated Types
Any parameter of an enumerated type must be a valid enumerant for that type. A enumerant is valid if:
-
The enumerant is defined as part of the enumerated type.
-
The enumerant is not one of the special values defined for the enumerated type, which are suffixed with
_BEGIN_RANGE,_END_RANGE,_RANGE_SIZEor_MAX_ENUM1.- 1
-
The meaning of these special tokens is not exposed in the Vulkan Specification. They are not part of the API, and they should not be used by applications. Their original intended use was for internal consumption by Vulkan implementations. Even that use will no longer be supported in the future, but they will be retained for backwards compatibility reasons.
Any enumerated type returned from a query command or otherwise output from Vulkan to the application must not have a reserved value. Reserved values are values not defined by any extension for that enumerated type.
|
Note
This language is intended to accomodate cases such as “hidden” extensions known only to driver internals, or layers enabling extensions without knowledge of the application, without allowing return of values not defined by any extension. |
Valid Usage for Flags
A collection of flags is represented by a bitmask using the type
VkFlags:
typedef uint32_t VkFlags;
Bitmasks are passed to many commands and structures to compactly represent
options, but VkFlags is not used directly in the API.
Instead, a Vk*Flags type which is an alias of VkFlags, and
whose name matches the corresponding Vk*FlagBits that are valid for
that type, is used.
Any Vk*Flags member or parameter used in the API as an input must be
a valid combination of bit flags.
A valid combination is either zero or the bitwise OR of valid bit flags.
A bit flag is valid if:
-
The bit flag is defined as part of the
Vk*FlagBitstype, where the bits type is obtained by taking the flag type and replacing the trailingFlagswithFlagBits. For example, a flag value of type VkColorComponentFlags must contain only bit flags defined by VkColorComponentFlagBits. -
The flag is allowed in the context in which it is being used. For example, in some cases, certain bit flags or combinations of bit flags are mutually exclusive.
Any Vk*Flags member or parameter returned from a query command or
otherwise output from Vulkan to the application may contain bit flags
undefined in its corresponding Vk*FlagBits type.
An application cannot rely on the state of these unspecified bits.
Valid Usage for Structure Types
Any parameter that is a structure containing a sType member must have
a value of sType which is a valid VkStructureType value matching
the type of the structure.
Structure types supported by the Vulkan API include:
typedef enum VkStructureType {
VK_STRUCTURE_TYPE_APPLICATION_INFO = 0,
VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO = 1,
VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO = 2,
VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO = 3,
VK_STRUCTURE_TYPE_SUBMIT_INFO = 4,
VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO = 5,
VK_STRUCTURE_TYPE_MAPPED_MEMORY_RANGE = 6,
VK_STRUCTURE_TYPE_BIND_SPARSE_INFO = 7,
VK_STRUCTURE_TYPE_FENCE_CREATE_INFO = 8,
VK_STRUCTURE_TYPE_SEMAPHORE_CREATE_INFO = 9,
VK_STRUCTURE_TYPE_EVENT_CREATE_INFO = 10,
VK_STRUCTURE_TYPE_QUERY_POOL_CREATE_INFO = 11,
VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO = 12,
VK_STRUCTURE_TYPE_BUFFER_VIEW_CREATE_INFO = 13,
VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO = 14,
VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO = 15,
VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO = 16,
VK_STRUCTURE_TYPE_PIPELINE_CACHE_CREATE_INFO = 17,
VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO = 18,
VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO = 19,
VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO = 20,
VK_STRUCTURE_TYPE_PIPELINE_TESSELLATION_STATE_CREATE_INFO = 21,
VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO = 22,
VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO = 23,
VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO = 24,
VK_STRUCTURE_TYPE_PIPELINE_DEPTH_STENCIL_STATE_CREATE_INFO = 25,
VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO = 26,
VK_STRUCTURE_TYPE_PIPELINE_DYNAMIC_STATE_CREATE_INFO = 27,
VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO = 28,
VK_STRUCTURE_TYPE_COMPUTE_PIPELINE_CREATE_INFO = 29,
VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO = 30,
VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO = 31,
VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO = 32,
VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO = 33,
VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO = 34,
VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET = 35,
VK_STRUCTURE_TYPE_COPY_DESCRIPTOR_SET = 36,
VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO = 37,
VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO = 38,
VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO = 39,
VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO = 40,
VK_STRUCTURE_TYPE_COMMAND_BUFFER_INHERITANCE_INFO = 41,
VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO = 42,
VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO = 43,
VK_STRUCTURE_TYPE_BUFFER_MEMORY_BARRIER = 44,
VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER = 45,
VK_STRUCTURE_TYPE_MEMORY_BARRIER = 46,
VK_STRUCTURE_TYPE_LOADER_INSTANCE_CREATE_INFO = 47,
VK_STRUCTURE_TYPE_LOADER_DEVICE_CREATE_INFO = 48,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SUBGROUP_PROPERTIES = 1000094000,
VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_INFO = 1000157000,
VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_INFO = 1000157001,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_16BIT_STORAGE_FEATURES = 1000083000,
VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS = 1000127000,
VK_STRUCTURE_TYPE_MEMORY_DEDICATED_ALLOCATE_INFO = 1000127001,
VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_FLAGS_INFO = 1000060000,
VK_STRUCTURE_TYPE_DEVICE_GROUP_RENDER_PASS_BEGIN_INFO = 1000060003,
VK_STRUCTURE_TYPE_DEVICE_GROUP_COMMAND_BUFFER_BEGIN_INFO = 1000060004,
VK_STRUCTURE_TYPE_DEVICE_GROUP_SUBMIT_INFO = 1000060005,
VK_STRUCTURE_TYPE_DEVICE_GROUP_BIND_SPARSE_INFO = 1000060006,
VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_DEVICE_GROUP_INFO = 1000060013,
VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_DEVICE_GROUP_INFO = 1000060014,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_GROUP_PROPERTIES = 1000070000,
VK_STRUCTURE_TYPE_DEVICE_GROUP_DEVICE_CREATE_INFO = 1000070001,
VK_STRUCTURE_TYPE_BUFFER_MEMORY_REQUIREMENTS_INFO_2 = 1000146000,
VK_STRUCTURE_TYPE_IMAGE_MEMORY_REQUIREMENTS_INFO_2 = 1000146001,
VK_STRUCTURE_TYPE_IMAGE_SPARSE_MEMORY_REQUIREMENTS_INFO_2 = 1000146002,
VK_STRUCTURE_TYPE_MEMORY_REQUIREMENTS_2 = 1000146003,
VK_STRUCTURE_TYPE_SPARSE_IMAGE_MEMORY_REQUIREMENTS_2 = 1000146004,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FEATURES_2 = 1000059000,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2 = 1000059001,
VK_STRUCTURE_TYPE_FORMAT_PROPERTIES_2 = 1000059002,
VK_STRUCTURE_TYPE_IMAGE_FORMAT_PROPERTIES_2 = 1000059003,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_FORMAT_INFO_2 = 1000059004,
VK_STRUCTURE_TYPE_QUEUE_FAMILY_PROPERTIES_2 = 1000059005,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PROPERTIES_2 = 1000059006,
VK_STRUCTURE_TYPE_SPARSE_IMAGE_FORMAT_PROPERTIES_2 = 1000059007,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SPARSE_IMAGE_FORMAT_INFO_2 = 1000059008,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_POINT_CLIPPING_PROPERTIES = 1000117000,
VK_STRUCTURE_TYPE_RENDER_PASS_INPUT_ATTACHMENT_ASPECT_CREATE_INFO = 1000117001,
VK_STRUCTURE_TYPE_IMAGE_VIEW_USAGE_CREATE_INFO = 1000117002,
VK_STRUCTURE_TYPE_PIPELINE_TESSELLATION_DOMAIN_ORIGIN_STATE_CREATE_INFO = 1000117003,
VK_STRUCTURE_TYPE_RENDER_PASS_MULTIVIEW_CREATE_INFO = 1000053000,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_FEATURES = 1000053001,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PROPERTIES = 1000053002,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTER_FEATURES = 1000120000,
VK_STRUCTURE_TYPE_PROTECTED_SUBMIT_INFO = 1000145000,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROTECTED_MEMORY_FEATURES = 1000145001,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROTECTED_MEMORY_PROPERTIES = 1000145002,
VK_STRUCTURE_TYPE_DEVICE_QUEUE_INFO_2 = 1000145003,
VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_CREATE_INFO = 1000156000,
VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_INFO = 1000156001,
VK_STRUCTURE_TYPE_BIND_IMAGE_PLANE_MEMORY_INFO = 1000156002,
VK_STRUCTURE_TYPE_IMAGE_PLANE_MEMORY_REQUIREMENTS_INFO = 1000156003,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLER_YCBCR_CONVERSION_FEATURES = 1000156004,
VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_IMAGE_FORMAT_PROPERTIES = 1000156005,
VK_STRUCTURE_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_CREATE_INFO = 1000085000,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_IMAGE_FORMAT_INFO = 1000071000,
VK_STRUCTURE_TYPE_EXTERNAL_IMAGE_FORMAT_PROPERTIES = 1000071001,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_BUFFER_INFO = 1000071002,
VK_STRUCTURE_TYPE_EXTERNAL_BUFFER_PROPERTIES = 1000071003,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ID_PROPERTIES = 1000071004,
VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_BUFFER_CREATE_INFO = 1000072000,
VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO = 1000072001,
VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO = 1000072002,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_FENCE_INFO = 1000112000,
VK_STRUCTURE_TYPE_EXTERNAL_FENCE_PROPERTIES = 1000112001,
VK_STRUCTURE_TYPE_EXPORT_FENCE_CREATE_INFO = 1000113000,
VK_STRUCTURE_TYPE_EXPORT_SEMAPHORE_CREATE_INFO = 1000077000,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_SEMAPHORE_INFO = 1000076000,
VK_STRUCTURE_TYPE_EXTERNAL_SEMAPHORE_PROPERTIES = 1000076001,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MAINTENANCE_3_PROPERTIES = 1000168000,
VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_SUPPORT = 1000168001,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_DRAW_PARAMETER_FEATURES = 1000063000,
VK_STRUCTURE_TYPE_SWAPCHAIN_CREATE_INFO_KHR = 1000001000,
VK_STRUCTURE_TYPE_PRESENT_INFO_KHR = 1000001001,
VK_STRUCTURE_TYPE_DEVICE_GROUP_PRESENT_CAPABILITIES_KHR = 1000060007,
VK_STRUCTURE_TYPE_IMAGE_SWAPCHAIN_CREATE_INFO_KHR = 1000060008,
VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_SWAPCHAIN_INFO_KHR = 1000060009,
VK_STRUCTURE_TYPE_ACQUIRE_NEXT_IMAGE_INFO_KHR = 1000060010,
VK_STRUCTURE_TYPE_DEVICE_GROUP_PRESENT_INFO_KHR = 1000060011,
VK_STRUCTURE_TYPE_DEVICE_GROUP_SWAPCHAIN_CREATE_INFO_KHR = 1000060012,
VK_STRUCTURE_TYPE_DISPLAY_MODE_CREATE_INFO_KHR = 1000002000,
VK_STRUCTURE_TYPE_DISPLAY_SURFACE_CREATE_INFO_KHR = 1000002001,
VK_STRUCTURE_TYPE_DISPLAY_PRESENT_INFO_KHR = 1000003000,
VK_STRUCTURE_TYPE_XLIB_SURFACE_CREATE_INFO_KHR = 1000004000,
VK_STRUCTURE_TYPE_XCB_SURFACE_CREATE_INFO_KHR = 1000005000,
VK_STRUCTURE_TYPE_WAYLAND_SURFACE_CREATE_INFO_KHR = 1000006000,
VK_STRUCTURE_TYPE_MIR_SURFACE_CREATE_INFO_KHR = 1000007000,
VK_STRUCTURE_TYPE_ANDROID_SURFACE_CREATE_INFO_KHR = 1000008000,
VK_STRUCTURE_TYPE_WIN32_SURFACE_CREATE_INFO_KHR = 1000009000,
VK_STRUCTURE_TYPE_DEBUG_REPORT_CALLBACK_CREATE_INFO_EXT = 1000011000,
VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_RASTERIZATION_ORDER_AMD = 1000018000,
VK_STRUCTURE_TYPE_DEBUG_MARKER_OBJECT_NAME_INFO_EXT = 1000022000,
VK_STRUCTURE_TYPE_DEBUG_MARKER_OBJECT_TAG_INFO_EXT = 1000022001,
VK_STRUCTURE_TYPE_DEBUG_MARKER_MARKER_INFO_EXT = 1000022002,
VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_IMAGE_CREATE_INFO_NV = 1000026000,
VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_BUFFER_CREATE_INFO_NV = 1000026001,
VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_MEMORY_ALLOCATE_INFO_NV = 1000026002,
VK_STRUCTURE_TYPE_TEXTURE_LOD_GATHER_FORMAT_PROPERTIES_AMD = 1000041000,
VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO_NV = 1000056000,
VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO_NV = 1000056001,
VK_STRUCTURE_TYPE_IMPORT_MEMORY_WIN32_HANDLE_INFO_NV = 1000057000,
VK_STRUCTURE_TYPE_EXPORT_MEMORY_WIN32_HANDLE_INFO_NV = 1000057001,
VK_STRUCTURE_TYPE_WIN32_KEYED_MUTEX_ACQUIRE_RELEASE_INFO_NV = 1000058000,
VK_STRUCTURE_TYPE_VALIDATION_FLAGS_EXT = 1000061000,
VK_STRUCTURE_TYPE_VI_SURFACE_CREATE_INFO_NN = 1000062000,
VK_STRUCTURE_TYPE_IMPORT_MEMORY_WIN32_HANDLE_INFO_KHR = 1000073000,
VK_STRUCTURE_TYPE_EXPORT_MEMORY_WIN32_HANDLE_INFO_KHR = 1000073001,
VK_STRUCTURE_TYPE_MEMORY_WIN32_HANDLE_PROPERTIES_KHR = 1000073002,
VK_STRUCTURE_TYPE_MEMORY_GET_WIN32_HANDLE_INFO_KHR = 1000073003,
VK_STRUCTURE_TYPE_IMPORT_MEMORY_FD_INFO_KHR = 1000074000,
VK_STRUCTURE_TYPE_MEMORY_FD_PROPERTIES_KHR = 1000074001,
VK_STRUCTURE_TYPE_MEMORY_GET_FD_INFO_KHR = 1000074002,
VK_STRUCTURE_TYPE_WIN32_KEYED_MUTEX_ACQUIRE_RELEASE_INFO_KHR = 1000075000,
VK_STRUCTURE_TYPE_IMPORT_SEMAPHORE_WIN32_HANDLE_INFO_KHR = 1000078000,
VK_STRUCTURE_TYPE_EXPORT_SEMAPHORE_WIN32_HANDLE_INFO_KHR = 1000078001,
VK_STRUCTURE_TYPE_D3D12_FENCE_SUBMIT_INFO_KHR = 1000078002,
VK_STRUCTURE_TYPE_SEMAPHORE_GET_WIN32_HANDLE_INFO_KHR = 1000078003,
VK_STRUCTURE_TYPE_IMPORT_SEMAPHORE_FD_INFO_KHR = 1000079000,
VK_STRUCTURE_TYPE_SEMAPHORE_GET_FD_INFO_KHR = 1000079001,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PUSH_DESCRIPTOR_PROPERTIES_KHR = 1000080000,
VK_STRUCTURE_TYPE_PRESENT_REGIONS_KHR = 1000084000,
VK_STRUCTURE_TYPE_OBJECT_TABLE_CREATE_INFO_NVX = 1000086000,
VK_STRUCTURE_TYPE_INDIRECT_COMMANDS_LAYOUT_CREATE_INFO_NVX = 1000086001,
VK_STRUCTURE_TYPE_CMD_PROCESS_COMMANDS_INFO_NVX = 1000086002,
VK_STRUCTURE_TYPE_CMD_RESERVE_SPACE_FOR_COMMANDS_INFO_NVX = 1000086003,
VK_STRUCTURE_TYPE_DEVICE_GENERATED_COMMANDS_LIMITS_NVX = 1000086004,
VK_STRUCTURE_TYPE_DEVICE_GENERATED_COMMANDS_FEATURES_NVX = 1000086005,
VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_W_SCALING_STATE_CREATE_INFO_NV = 1000087000,
VK_STRUCTURE_TYPE_SURFACE_CAPABILITIES_2_EXT = 1000090000,
VK_STRUCTURE_TYPE_DISPLAY_POWER_INFO_EXT = 1000091000,
VK_STRUCTURE_TYPE_DEVICE_EVENT_INFO_EXT = 1000091001,
VK_STRUCTURE_TYPE_DISPLAY_EVENT_INFO_EXT = 1000091002,
VK_STRUCTURE_TYPE_SWAPCHAIN_COUNTER_CREATE_INFO_EXT = 1000091003,
VK_STRUCTURE_TYPE_PRESENT_TIMES_INFO_GOOGLE = 1000092000,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PER_VIEW_ATTRIBUTES_PROPERTIES_NVX = 1000097000,
VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_SWIZZLE_STATE_CREATE_INFO_NV = 1000098000,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DISCARD_RECTANGLE_PROPERTIES_EXT = 1000099000,
VK_STRUCTURE_TYPE_PIPELINE_DISCARD_RECTANGLE_STATE_CREATE_INFO_EXT = 1000099001,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_CONSERVATIVE_RASTERIZATION_PROPERTIES_EXT = 1000101000,
VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_CONSERVATIVE_STATE_CREATE_INFO_EXT = 1000101001,
VK_STRUCTURE_TYPE_HDR_METADATA_EXT = 1000105000,
VK_STRUCTURE_TYPE_SHARED_PRESENT_SURFACE_CAPABILITIES_KHR = 1000111000,
VK_STRUCTURE_TYPE_IMPORT_FENCE_WIN32_HANDLE_INFO_KHR = 1000114000,
VK_STRUCTURE_TYPE_EXPORT_FENCE_WIN32_HANDLE_INFO_KHR = 1000114001,
VK_STRUCTURE_TYPE_FENCE_GET_WIN32_HANDLE_INFO_KHR = 1000114002,
VK_STRUCTURE_TYPE_IMPORT_FENCE_FD_INFO_KHR = 1000115000,
VK_STRUCTURE_TYPE_FENCE_GET_FD_INFO_KHR = 1000115001,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SURFACE_INFO_2_KHR = 1000119000,
VK_STRUCTURE_TYPE_SURFACE_CAPABILITIES_2_KHR = 1000119001,
VK_STRUCTURE_TYPE_SURFACE_FORMAT_2_KHR = 1000119002,
VK_STRUCTURE_TYPE_DISPLAY_PROPERTIES_2_KHR = 1000121000,
VK_STRUCTURE_TYPE_DISPLAY_PLANE_PROPERTIES_2_KHR = 1000121001,
VK_STRUCTURE_TYPE_DISPLAY_MODE_PROPERTIES_2_KHR = 1000121002,
VK_STRUCTURE_TYPE_DISPLAY_PLANE_INFO_2_KHR = 1000121003,
VK_STRUCTURE_TYPE_DISPLAY_PLANE_CAPABILITIES_2_KHR = 1000121004,
VK_STRUCTURE_TYPE_IOS_SURFACE_CREATE_INFO_MVK = 1000122000,
VK_STRUCTURE_TYPE_MACOS_SURFACE_CREATE_INFO_MVK = 1000123000,
VK_STRUCTURE_TYPE_DEBUG_UTILS_OBJECT_NAME_INFO_EXT = 1000128000,
VK_STRUCTURE_TYPE_DEBUG_UTILS_OBJECT_TAG_INFO_EXT = 1000128001,
VK_STRUCTURE_TYPE_DEBUG_UTILS_LABEL_EXT = 1000128002,
VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CALLBACK_DATA_EXT = 1000128003,
VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CREATE_INFO_EXT = 1000128004,
VK_STRUCTURE_TYPE_ANDROID_HARDWARE_BUFFER_USAGE_ANDROID = 1000129000,
VK_STRUCTURE_TYPE_ANDROID_HARDWARE_BUFFER_PROPERTIES_ANDROID = 1000129001,
VK_STRUCTURE_TYPE_ANDROID_HARDWARE_BUFFER_FORMAT_PROPERTIES_ANDROID = 1000129002,
VK_STRUCTURE_TYPE_IMPORT_ANDROID_HARDWARE_BUFFER_INFO_ANDROID = 1000129003,
VK_STRUCTURE_TYPE_MEMORY_GET_ANDROID_HARDWARE_BUFFER_INFO_ANDROID = 1000129004,
VK_STRUCTURE_TYPE_EXTERNAL_FORMAT_ANDROID = 1000129005,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLER_FILTER_MINMAX_PROPERTIES_EXT = 1000130000,
VK_STRUCTURE_TYPE_SAMPLER_REDUCTION_MODE_CREATE_INFO_EXT = 1000130001,
VK_STRUCTURE_TYPE_SAMPLE_LOCATIONS_INFO_EXT = 1000143000,
VK_STRUCTURE_TYPE_RENDER_PASS_SAMPLE_LOCATIONS_BEGIN_INFO_EXT = 1000143001,
VK_STRUCTURE_TYPE_PIPELINE_SAMPLE_LOCATIONS_STATE_CREATE_INFO_EXT = 1000143002,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLE_LOCATIONS_PROPERTIES_EXT = 1000143003,
VK_STRUCTURE_TYPE_MULTISAMPLE_PROPERTIES_EXT = 1000143004,
VK_STRUCTURE_TYPE_IMAGE_FORMAT_LIST_CREATE_INFO_KHR = 1000147000,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BLEND_OPERATION_ADVANCED_FEATURES_EXT = 1000148000,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BLEND_OPERATION_ADVANCED_PROPERTIES_EXT = 1000148001,
VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_ADVANCED_STATE_CREATE_INFO_EXT = 1000148002,
VK_STRUCTURE_TYPE_PIPELINE_COVERAGE_TO_COLOR_STATE_CREATE_INFO_NV = 1000149000,
VK_STRUCTURE_TYPE_PIPELINE_COVERAGE_MODULATION_STATE_CREATE_INFO_NV = 1000152000,
VK_STRUCTURE_TYPE_VALIDATION_CACHE_CREATE_INFO_EXT = 1000160000,
VK_STRUCTURE_TYPE_SHADER_MODULE_VALIDATION_CACHE_CREATE_INFO_EXT = 1000160001,
VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_BINDING_FLAGS_CREATE_INFO_EXT = 1000161000,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_FEATURES_EXT = 1000161001,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_PROPERTIES_EXT = 1000161002,
VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_ALLOCATE_INFO_EXT = 1000161003,
VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_LAYOUT_SUPPORT_EXT = 1000161004,
VK_STRUCTURE_TYPE_DEVICE_QUEUE_GLOBAL_PRIORITY_CREATE_INFO_EXT = 1000174000,
VK_STRUCTURE_TYPE_IMPORT_MEMORY_HOST_POINTER_INFO_EXT = 1000178000,
VK_STRUCTURE_TYPE_MEMORY_HOST_POINTER_PROPERTIES_EXT = 1000178001,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_MEMORY_HOST_PROPERTIES_EXT = 1000178002,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_CORE_PROPERTIES_AMD = 1000185000,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VERTEX_ATTRIBUTE_DIVISOR_PROPERTIES_EXT = 1000190000,
VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_DIVISOR_STATE_CREATE_INFO_EXT = 1000190001,
VK_STRUCTURE_TYPE_RENDER_PASS_MULTIVIEW_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_RENDER_PASS_MULTIVIEW_CREATE_INFO,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_FEATURES,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PROPERTIES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PROPERTIES,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FEATURES_2_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FEATURES_2,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2,
VK_STRUCTURE_TYPE_FORMAT_PROPERTIES_2_KHR = VK_STRUCTURE_TYPE_FORMAT_PROPERTIES_2,
VK_STRUCTURE_TYPE_IMAGE_FORMAT_PROPERTIES_2_KHR = VK_STRUCTURE_TYPE_IMAGE_FORMAT_PROPERTIES_2,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_FORMAT_INFO_2_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_FORMAT_INFO_2,
VK_STRUCTURE_TYPE_QUEUE_FAMILY_PROPERTIES_2_KHR = VK_STRUCTURE_TYPE_QUEUE_FAMILY_PROPERTIES_2,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PROPERTIES_2_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PROPERTIES_2,
VK_STRUCTURE_TYPE_SPARSE_IMAGE_FORMAT_PROPERTIES_2_KHR = VK_STRUCTURE_TYPE_SPARSE_IMAGE_FORMAT_PROPERTIES_2,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SPARSE_IMAGE_FORMAT_INFO_2_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SPARSE_IMAGE_FORMAT_INFO_2,
VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_FLAGS_INFO_KHR = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_FLAGS_INFO,
VK_STRUCTURE_TYPE_DEVICE_GROUP_RENDER_PASS_BEGIN_INFO_KHR = VK_STRUCTURE_TYPE_DEVICE_GROUP_RENDER_PASS_BEGIN_INFO,
VK_STRUCTURE_TYPE_DEVICE_GROUP_COMMAND_BUFFER_BEGIN_INFO_KHR = VK_STRUCTURE_TYPE_DEVICE_GROUP_COMMAND_BUFFER_BEGIN_INFO,
VK_STRUCTURE_TYPE_DEVICE_GROUP_SUBMIT_INFO_KHR = VK_STRUCTURE_TYPE_DEVICE_GROUP_SUBMIT_INFO,
VK_STRUCTURE_TYPE_DEVICE_GROUP_BIND_SPARSE_INFO_KHR = VK_STRUCTURE_TYPE_DEVICE_GROUP_BIND_SPARSE_INFO,
VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_DEVICE_GROUP_INFO_KHR = VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_DEVICE_GROUP_INFO,
VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_DEVICE_GROUP_INFO_KHR = VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_DEVICE_GROUP_INFO,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_GROUP_PROPERTIES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_GROUP_PROPERTIES,
VK_STRUCTURE_TYPE_DEVICE_GROUP_DEVICE_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_DEVICE_GROUP_DEVICE_CREATE_INFO,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_IMAGE_FORMAT_INFO_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_IMAGE_FORMAT_INFO,
VK_STRUCTURE_TYPE_EXTERNAL_IMAGE_FORMAT_PROPERTIES_KHR = VK_STRUCTURE_TYPE_EXTERNAL_IMAGE_FORMAT_PROPERTIES,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_BUFFER_INFO_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_BUFFER_INFO,
VK_STRUCTURE_TYPE_EXTERNAL_BUFFER_PROPERTIES_KHR = VK_STRUCTURE_TYPE_EXTERNAL_BUFFER_PROPERTIES,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ID_PROPERTIES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ID_PROPERTIES,
VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_BUFFER_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_BUFFER_CREATE_INFO,
VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO,
VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO_KHR = VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_SEMAPHORE_INFO_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_SEMAPHORE_INFO,
VK_STRUCTURE_TYPE_EXTERNAL_SEMAPHORE_PROPERTIES_KHR = VK_STRUCTURE_TYPE_EXTERNAL_SEMAPHORE_PROPERTIES,
VK_STRUCTURE_TYPE_EXPORT_SEMAPHORE_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_EXPORT_SEMAPHORE_CREATE_INFO,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_16BIT_STORAGE_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_16BIT_STORAGE_FEATURES,
VK_STRUCTURE_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_CREATE_INFO,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_FENCE_INFO_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_FENCE_INFO,
VK_STRUCTURE_TYPE_EXTERNAL_FENCE_PROPERTIES_KHR = VK_STRUCTURE_TYPE_EXTERNAL_FENCE_PROPERTIES,
VK_STRUCTURE_TYPE_EXPORT_FENCE_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_EXPORT_FENCE_CREATE_INFO,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_POINT_CLIPPING_PROPERTIES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_POINT_CLIPPING_PROPERTIES,
VK_STRUCTURE_TYPE_RENDER_PASS_INPUT_ATTACHMENT_ASPECT_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_RENDER_PASS_INPUT_ATTACHMENT_ASPECT_CREATE_INFO,
VK_STRUCTURE_TYPE_IMAGE_VIEW_USAGE_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_IMAGE_VIEW_USAGE_CREATE_INFO,
VK_STRUCTURE_TYPE_PIPELINE_TESSELLATION_DOMAIN_ORIGIN_STATE_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_PIPELINE_TESSELLATION_DOMAIN_ORIGIN_STATE_CREATE_INFO,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTER_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTER_FEATURES,
VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS_KHR = VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS,
VK_STRUCTURE_TYPE_MEMORY_DEDICATED_ALLOCATE_INFO_KHR = VK_STRUCTURE_TYPE_MEMORY_DEDICATED_ALLOCATE_INFO,
VK_STRUCTURE_TYPE_BUFFER_MEMORY_REQUIREMENTS_INFO_2_KHR = VK_STRUCTURE_TYPE_BUFFER_MEMORY_REQUIREMENTS_INFO_2,
VK_STRUCTURE_TYPE_IMAGE_MEMORY_REQUIREMENTS_INFO_2_KHR = VK_STRUCTURE_TYPE_IMAGE_MEMORY_REQUIREMENTS_INFO_2,
VK_STRUCTURE_TYPE_IMAGE_SPARSE_MEMORY_REQUIREMENTS_INFO_2_KHR = VK_STRUCTURE_TYPE_IMAGE_SPARSE_MEMORY_REQUIREMENTS_INFO_2,
VK_STRUCTURE_TYPE_MEMORY_REQUIREMENTS_2_KHR = VK_STRUCTURE_TYPE_MEMORY_REQUIREMENTS_2,
VK_STRUCTURE_TYPE_SPARSE_IMAGE_MEMORY_REQUIREMENTS_2_KHR = VK_STRUCTURE_TYPE_SPARSE_IMAGE_MEMORY_REQUIREMENTS_2,
VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_CREATE_INFO,
VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_INFO_KHR = VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_INFO,
VK_STRUCTURE_TYPE_BIND_IMAGE_PLANE_MEMORY_INFO_KHR = VK_STRUCTURE_TYPE_BIND_IMAGE_PLANE_MEMORY_INFO,
VK_STRUCTURE_TYPE_IMAGE_PLANE_MEMORY_REQUIREMENTS_INFO_KHR = VK_STRUCTURE_TYPE_IMAGE_PLANE_MEMORY_REQUIREMENTS_INFO,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLER_YCBCR_CONVERSION_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLER_YCBCR_CONVERSION_FEATURES,
VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_IMAGE_FORMAT_PROPERTIES_KHR = VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_IMAGE_FORMAT_PROPERTIES,
VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_INFO_KHR = VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_INFO,
VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_INFO_KHR = VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_INFO,
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MAINTENANCE_3_PROPERTIES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MAINTENANCE_3_PROPERTIES,
VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_SUPPORT_KHR = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_SUPPORT,
} VkStructureType;
Each value corresponds to a particular structure with a sType member
with a matching name.
As a general rule, the name of each VkStructureType value is obtained
by taking the name of the structure, stripping the leading Vk,
prefixing each capital letter with _, converting the entire resulting
string to upper case, and prefixing it with VK_STRUCTURE_TYPE_.
For example, structures of type VkImageCreateInfo correspond to a
VkStructureType of VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO, and thus
its sType member must equal that when it is passed to the API.
The values VK_STRUCTURE_TYPE_LOADER_INSTANCE_CREATE_INFO and
VK_STRUCTURE_TYPE_LOADER_DEVICE_CREATE_INFO are reserved for internal
use by the loader, and do not have corresponding Vulkan structures in this
Specification.
Valid Usage for Structure Pointer Chains
Any parameter that is a structure containing a void* pNext member
must have a value of pNext that is either NULL, or points to a
valid structure defined by an extension, containing sType and
pNext members as described in the Vulkan
Documentation and Extensions document in the section “Extension
Interactions”.
The set of structures connected by pNext pointers is referred to as a
pNext chain.
If that extension is supported by the implementation, then it must be
enabled.
Each type of valid structure must not appear more than once in a
pNext chain.
Any component of the implementation (the loader, any enabled layers, and
drivers) must skip over, without processing (other than reading the
sType and pNext members) any structures in the chain with
sType values not defined by extensions supported by that component.
Extension structures are not described in the base Vulkan Specification, but either in layered Specifications incorporating those extensions, or in separate vendor-provided documents.
As a convenience to implementations and layers needing to iterate through a structure pointer chain, the Vulkan API provides the following base structures:
typedef struct VkBaseInStructure {
VkStructureType sType;
const struct VkBaseInStructure* pNext;
} VkBaseInStructure;
typedef struct VkBaseOutStructure {
VkStructureType sType;
struct VkBaseOutStructure* pNext;
} VkBaseOutStructure;
VkBaseInStructure can be used to facilitate iterating through a
read-only structure pointer chain.
VkBaseOutStructure can be used to facilitate iterating through a
structure pointer chain that returns data back to the application.
These structures allow for some type safety and can be used by Vulkan API
functions that operate on generic inputs and outputs.
Valid Usage for Nested Structures
The above conditions also apply recursively to members of structures provided as input to a command, either as a direct argument to the command, or themselves a member of another structure.
Specifics on valid usage of each command are covered in their individual sections.
Valid Usage for Extensions
Instance-level functionality or behavior added by an instance extension to the API must not be used unless that extension is supported by the instance as determined by vkEnumerateInstanceExtensionProperties, and that extension is enabled in VkInstanceCreateInfo.
Physical-device-level functionality or behavior added by an instance extension to the API must not be used unless that extension is supported by the instance as determined by vkEnumerateInstanceExtensionProperties, and that extension is enabled in VkInstanceCreateInfo.
Physical-device-level functionality or behavior added by a device extension to the API must not be used unless the conditions described in Extending Physical Device Core Functionality are met.
Device functionality or behavior added by a device extension to the API must not be used unless that extension is supported by the device as determined by vkEnumerateDeviceExtensionProperties, and that extension is enabled in VkDeviceCreateInfo.
Valid Usage for Newer Core Versions
Instance-level functionality or behavior added by a new core version of the API must not be used unless it is supported by the instance as determined by vkEnumerateInstanceVersion.
Physical-device-level functionality or behavior added by a new core version of the API must not be used unless it is supported by the physical device as determined by vkGetPhysicalDeviceProperties.
Device-level functionality or behavior added by a new core version of the API must not be used unless it is supported by the device as determined by vkGetPhysicalDeviceProperties.
2.7.3. Return Codes
While the core Vulkan API is not designed to capture incorrect usage, some circumstances still require return codes. Commands in Vulkan return their status via return codes that are in one of two categories:
-
Successful completion codes are returned when a command needs to communicate success or status information. All successful completion codes are non-negative values.
-
Run time error codes are returned when a command needs to communicate a failure that could only be detected at run time. All run time error codes are negative values.
All return codes in Vulkan are reported via VkResult return values. The possible codes are:
typedef enum VkResult {
VK_SUCCESS = 0,
VK_NOT_READY = 1,
VK_TIMEOUT = 2,
VK_EVENT_SET = 3,
VK_EVENT_RESET = 4,
VK_INCOMPLETE = 5,
VK_ERROR_OUT_OF_HOST_MEMORY = -1,
VK_ERROR_OUT_OF_DEVICE_MEMORY = -2,
VK_ERROR_INITIALIZATION_FAILED = -3,
VK_ERROR_DEVICE_LOST = -4,
VK_ERROR_MEMORY_MAP_FAILED = -5,
VK_ERROR_LAYER_NOT_PRESENT = -6,
VK_ERROR_EXTENSION_NOT_PRESENT = -7,
VK_ERROR_FEATURE_NOT_PRESENT = -8,
VK_ERROR_INCOMPATIBLE_DRIVER = -9,
VK_ERROR_TOO_MANY_OBJECTS = -10,
VK_ERROR_FORMAT_NOT_SUPPORTED = -11,
VK_ERROR_FRAGMENTED_POOL = -12,
VK_ERROR_OUT_OF_POOL_MEMORY = -1000069000,
VK_ERROR_INVALID_EXTERNAL_HANDLE = -1000072003,
VK_ERROR_SURFACE_LOST_KHR = -1000000000,
VK_ERROR_NATIVE_WINDOW_IN_USE_KHR = -1000000001,
VK_SUBOPTIMAL_KHR = 1000001003,
VK_ERROR_OUT_OF_DATE_KHR = -1000001004,
VK_ERROR_INCOMPATIBLE_DISPLAY_KHR = -1000003001,
VK_ERROR_VALIDATION_FAILED_EXT = -1000011001,
VK_ERROR_INVALID_SHADER_NV = -1000012000,
VK_ERROR_FRAGMENTATION_EXT = -1000161000,
VK_ERROR_NOT_PERMITTED_EXT = -1000174001,
VK_ERROR_OUT_OF_POOL_MEMORY_KHR = VK_ERROR_OUT_OF_POOL_MEMORY,
VK_ERROR_INVALID_EXTERNAL_HANDLE_KHR = VK_ERROR_INVALID_EXTERNAL_HANDLE,
} VkResult;
-
VK_SUCCESSCommand successfully completed -
VK_NOT_READYA fence or query has not yet completed -
VK_TIMEOUTA wait operation has not completed in the specified time -
VK_EVENT_SETAn event is signaled -
VK_EVENT_RESETAn event is unsignaled -
VK_INCOMPLETEA return array was too small for the result -
VK_SUBOPTIMAL_KHRA swapchain no longer matches the surface properties exactly, but can still be used to present to the surface successfully.
-
VK_ERROR_OUT_OF_HOST_MEMORYA host memory allocation has failed. -
VK_ERROR_OUT_OF_DEVICE_MEMORYA device memory allocation has failed. -
VK_ERROR_INITIALIZATION_FAILEDInitialization of an object could not be completed for implementation-specific reasons. -
VK_ERROR_DEVICE_LOSTThe logical or physical device has been lost. See Lost Device -
VK_ERROR_MEMORY_MAP_FAILEDMapping of a memory object has failed. -
VK_ERROR_LAYER_NOT_PRESENTA requested layer is not present or could not be loaded. -
VK_ERROR_EXTENSION_NOT_PRESENTA requested extension is not supported. -
VK_ERROR_FEATURE_NOT_PRESENTA requested feature is not supported. -
VK_ERROR_INCOMPATIBLE_DRIVERThe requested version of Vulkan is not supported by the driver or is otherwise incompatible for implementation-specific reasons. -
VK_ERROR_TOO_MANY_OBJECTSToo many objects of the type have already been created. -
VK_ERROR_FORMAT_NOT_SUPPORTEDA requested format is not supported on this device. -
VK_ERROR_FRAGMENTED_POOLA pool allocation has failed due to fragmentation of the pool’s memory. This must only be returned if no attempt to allocate host or device memory was made to accomodate the new allocation. This should be returned in preference toVK_ERROR_OUT_OF_POOL_MEMORY, but only if the implementation is certain that the pool allocation failure was due to fragmentation. -
VK_ERROR_SURFACE_LOST_KHRA surface is no longer available. -
VK_ERROR_NATIVE_WINDOW_IN_USE_KHRThe requested window is already in use by Vulkan or another API in a manner which prevents it from being used again. -
VK_ERROR_OUT_OF_DATE_KHRA surface has changed in such a way that it is no longer compatible with the swapchain, and further presentation requests using the swapchain will fail. Applications must query the new surface properties and recreate their swapchain if they wish to continue presenting to the surface. -
VK_ERROR_INCOMPATIBLE_DISPLAY_KHRThe display used by a swapchain does not use the same presentable image layout, or is incompatible in a way that prevents sharing an image. -
VK_ERROR_INVALID_SHADER_NVOne or more shaders failed to compile or link. More details are reported back to the application viaVK_EXT_debug_reportif enabled. -
VK_ERROR_OUT_OF_POOL_MEMORYA pool memory allocation has failed. This must only be returned if no attempt to allocate host or device memory was made to accomodate the new allocation. If the failure was definitely due to fragmentation of the pool,VK_ERROR_FRAGMENTED_POOLshould be returned instead. -
VK_ERROR_INVALID_EXTERNAL_HANDLEAn external handle is not a valid handle of the specified type. -
VK_ERROR_FRAGMENTATION_EXTA descriptor pool creation has failed due to fragmentation.
If a command returns a run time error, unless otherwise specified any output
parameters will have undefined contents, except that if the output parameter
is a structure with sType and pNext fields, those fields will be
unmodified.
Any structures chained from pNext will also have undefined contents,
except that sType and pNext will be unmodified.
Out of memory errors do not damage any currently existing Vulkan objects. Objects that have already been successfully created can still be used by the application.
Performance-critical commands generally do not have return codes.
If a run time error occurs in such commands, the implementation will defer
reporting the error until a specified point.
For commands that record into command buffers (vkCmd*) run time errors
are reported by vkEndCommandBuffer.
2.8. Numeric Representation and Computation
Implementations normally perform computations in floating-point, and must meet the range and precision requirements defined under “Floating-Point Computation” below.
These requirements only apply to computations performed in Vulkan operations outside of shader execution, such as texture image specification and sampling, and per-fragment operations. Range and precision requirements during shader execution differ and are specified by the Precision and Operation of SPIR-V Instructions section.
In some cases, the representation and/or precision of operations is implicitly limited by the specified format of vertex or texel data consumed by Vulkan. Specific floating-point formats are described later in this section.
2.8.1. Floating-Point Computation
Most floating-point computation is performed in SPIR-V shader modules. The properties of computation within shaders are constrained as defined by the Precision and Operation of SPIR-V Instructions section.
Some floating-point computation is performed outside of shaders, such as viewport and depth range calculations. For these computations, we do not specify how floating-point numbers are to be represented, or the details of how operations on them are performed, but only place minimal requirements on representation and precision as described in the remainder of this section.
|
editing-note
(Jon, Bug 14966) This is a rat’s nest of complexity, both in terms of describing/enumerating places such computation may take place (other than “not shader code”) and in how implementations may do it. We have consciously deferred the resolution of this issue to post-1.0, and in the meantime, the following language inherited from the OpenGL Specification is inserted as a placeholder. Hopefully it can be tightened up considerably. |
We require simply that numbers’ floating-point parts contain enough bits and that their exponent fields are large enough so that individual results of floating-point operations are accurate to about 1 part in 105. The maximum representable magnitude for all floating-point values must be at least 232.
-
x × 0 = 0 × x = 0 for any non-infinite and non-NaN x.
-
1 × x = x × 1 = x.
-
x + 0 = 0 + x = x.
-
00 = 1.
Occasionally, further requirements will be specified. Most single-precision floating-point formats meet these requirements.
The special values Inf and -Inf encode values with magnitudes too large to be represented; the special value NaN encodes “Not A Number” values resulting from undefined arithmetic operations such as 0 / 0. Implementations may support Inf and NaN in their floating-point computations.
Any representable floating-point value is legal as input to a Vulkan command that requires floating-point data. The result of providing a value that is not a floating-point number to such a command is unspecified, but must not lead to Vulkan interruption or termination. In IEEE 754 arithmetic, for example, providing a negative zero or a denormalized number to an Vulkan command must yield deterministic results, while providing a NaN or Inf yields unspecified results.
2.8.2. 16-Bit Floating-Point Numbers
16-bit floating point numbers are defined in the “16-bit floating point numbers” section of the Khronos Data Format Specification.
Any representable 16-bit floating-point value is legal as input to a Vulkan command that accepts 16-bit floating-point data. The result of providing a value that is not a floating-point number (such as Inf or NaN) to such a command is unspecified, but must not lead to Vulkan interruption or termination. Providing a denormalized number or negative zero to Vulkan must yield deterministic results.
2.8.3. Unsigned 11-Bit Floating-Point Numbers
Unsigned 11-bit floating point numbers are defined in the “Unsigned 11-bit floating point numbers” section of the Khronos Data Format Specification.
When a floating-point value is converted to an unsigned 11-bit floating-point representation, finite values are rounded to the closest representable finite value.
While less accurate, implementations are allowed to always round in the direction of zero. This means negative values are converted to zero. Likewise, finite positive values greater than 65024 (the maximum finite representable unsigned 11-bit floating-point value) are converted to 65024. Additionally: negative infinity is converted to zero; positive infinity is converted to positive infinity; and both positive and negative NaN are converted to positive NaN.
Any representable unsigned 11-bit floating-point value is legal as input to a Vulkan command that accepts 11-bit floating-point data. The result of providing a value that is not a floating-point number (such as Inf or NaN) to such a command is unspecified, but must not lead to Vulkan interruption or termination. Providing a denormalized number to Vulkan must yield deterministic results.
2.8.4. Unsigned 10-Bit Floating-Point Numbers
Unsigned 10-bit floating point numbers are defined in the “Unsigned 10-bit floating point numbers” section of the Khronos Data Format Specification.
When a floating-point value is converted to an unsigned 10-bit floating-point representation, finite values are rounded to the closest representable finite value.
While less accurate, implementations are allowed to always round in the direction of zero. This means negative values are converted to zero. Likewise, finite positive values greater than 64512 (the maximum finite representable unsigned 10-bit floating-point value) are converted to 64512. Additionally: negative infinity is converted to zero; positive infinity is converted to positive infinity; and both positive and negative NaN are converted to positive NaN.
Any representable unsigned 10-bit floating-point value is legal as input to a Vulkan command that accepts 10-bit floating-point data. The result of providing a value that is not a floating-point number (such as Inf or NaN) to such a command is unspecified, but must not lead to Vulkan interruption or termination. Providing a denormalized number to Vulkan must yield deterministic results.
2.8.5. General Requirements
Some calculations require division. In such cases (including implied divisions performed by vector normalization), division by zero produces an unspecified result but must not lead to Vulkan interruption or termination.
2.9. Fixed-Point Data Conversions
When generic vertex attributes and pixel color or depth components are represented as integers, they are often (but not always) considered to be normalized. Normalized integer values are treated specially when being converted to and from floating-point values, and are usually referred to as normalized fixed-point.
In the remainder of this section, b denotes the bit width of the fixed-point integer representation. When the integer is one of the types defined by the API, b is the bit width of that type. When the integer comes from an image containing color or depth component texels, b is the number of bits allocated to that component in its specified image format.
The signed and unsigned fixed-point representations are assumed to be b-bit binary two’s-complement integers and binary unsigned integers, respectively.
2.9.1. Conversion from Normalized Fixed-Point to Floating-Point
Unsigned normalized fixed-point integers represent numbers in the range [0,1]. The conversion from an unsigned normalized fixed-point value c to the corresponding floating-point value f is defined as
Signed normalized fixed-point integers represent numbers in the range [-1,1]. The conversion from a signed normalized fixed-point value c to the corresponding floating-point value f is performed using
Only the range [-2b-1 + 1, 2b-1 - 1] is used to represent signed fixed-point values in the range [-1,1]. For example, if b = 8, then the integer value -127 corresponds to -1.0 and the value 127 corresponds to 1.0. Note that while zero is exactly expressible in this representation, one value (-128 in the example) is outside the representable range, and must be clamped before use. This equation is used everywhere that signed normalized fixed-point values are converted to floating-point.
2.9.2. Conversion from Floating-Point to Normalized Fixed-Point
The conversion from a floating-point value f to the corresponding unsigned normalized fixed-point value c is defined by first clamping f to the range [0,1], then computing
-
c = convertFloatToUint(f × (2b - 1), b)
where convertFloatToUint}(r,b) returns one of the two unsigned binary integer values with exactly b bits which are closest to the floating-point value r. Implementations should round to nearest. If r is equal to an integer, then that integer value must be returned. In particular, if f is equal to 0.0 or 1.0, then c must be assigned 0 or 2b - 1, respectively.
The conversion from a floating-point value f to the corresponding signed normalized fixed-point value c is performed by clamping f to the range [-1,1], then computing
-
c = convertFloatToInt(f × (2b-1 - 1), b)
where convertFloatToInt(r,b) returns one of the two signed two’s-complement binary integer values with exactly b bits which are closest to the floating-point value r. Implementations should round to nearest. If r is equal to an integer, then that integer value must be returned. In particular, if f is equal to -1.0, 0.0, or 1.0, then c must be assigned -(2b-1 - 1), 0, or 2b-1 - 1, respectively.
This equation is used everywhere that floating-point values are converted to signed normalized fixed-point.
2.10. API Version Numbers and Semantics
The Vulkan version number is used in several places in the API. In each such use, the API major version number, minor version number, and patch version number are packed into a 32-bit integer as follows:
-
The major version number is a 10-bit integer packed into bits 31-22.
-
The minor version number is a 10-bit integer packed into bits 21-12.
-
The patch version number is a 12-bit integer packed into bits 11-0.
Differences in any of the Vulkan version numbers indicates a change to the API in some way, with each part of the version number indicating a different scope of changes.
A difference in patch version numbers indicates that some usually small part of the Specification or header has been modified, typically to fix a bug, and may have an impact on the behavior of existing functionality. Differences in this version number should not affect either full compatibility or backwards compatibility between two versions, or add additional interfaces to the API.
A difference in minor version numbers indicates that some amount of new functionality has been added. This will usually include new interfaces in the header, and may also include behavior changes and bug fixes. Functionality may be deprecated in a minor revision, but will not be removed. The patch version will continue to increment through minor version number changes since all minor versions are generated from the same source files, and changes to the source files may affect all minor versions within a major version. Differences in the patch version should not affect backwards compatibility, but will affect full compatibility. The patch version of the Specification is taken from VK_HEADER_VERSION.
A difference in major version numbers indicates a large set of changes to the API, potentially including new functionality and header interfaces, behavioral changes, removal of deprecated features, modification or outright replacement of any feature, and is thus very likely to break any and all compatibility. Differences in this version will typically require significant modification to an application in order for it to function.
C language macros for manipulating version numbers are defined in the Version Number Macros appendix.
2.11. Common Object Types
Some types of Vulkan objects are used in many different structures and command parameters, and are described here. These types include offsets, extents, and rectangles.
2.11.1. Offsets
Offsets are used to describe a pixel location within an image or framebuffer, as an (x,y) location for two-dimensional images, or an (x,y,z) location for three-dimensional images.
A two-dimensional offsets is defined by the structure:
typedef struct VkOffset2D {
int32_t x;
int32_t y;
} VkOffset2D;
-
xis the x offset. -
yis the y offset.
A three-dimensional offset is defined by the structure:
typedef struct VkOffset3D {
int32_t x;
int32_t y;
int32_t z;
} VkOffset3D;
-
xis the x offset. -
yis the y offset. -
zis the z offset.
2.11.2. Extents
Extents are used to describe the size of a rectangular region of pixels within an image or framebuffer, as (width,height) for two-dimensional images, or as (width,height,depth) for three-dimensional images.
A two-dimensional extent is defined by the structure:
typedef struct VkExtent2D {
uint32_t width;
uint32_t height;
} VkExtent2D;
-
widthis the width of the extent. -
heightis the height of the extent.
A three-dimensional extent is defined by the structure:
typedef struct VkExtent3D {
uint32_t width;
uint32_t height;
uint32_t depth;
} VkExtent3D;
-
widthis the width of the extent. -
heightis the height of the extent. -
depthis the depth of the extent.
2.11.3. Rectangles
Rectangles are used to describe a specified rectangular region of pixels within an image or framebuffer. Rectangles include both an offset and an extent of the same dimensionality, as described above. Two-dimensional rectangles are defined by the structure
typedef struct VkRect2D {
VkOffset2D offset;
VkExtent2D extent;
} VkRect2D;
-
offsetis a VkOffset2D specifying the rectangle offset. -
extentis a VkExtent2D specifying the rectangle extent.
3. Initialization
Before using Vulkan, an application must initialize it by loading the
Vulkan commands, and creating a VkInstance object.
3.1. Command Function Pointers
Vulkan commands are not necessarily exposed statically on a platform. Function pointers for all Vulkan commands can be obtained with the command:
PFN_vkVoidFunction vkGetInstanceProcAddr(
VkInstance instance,
const char* pName);
-
instanceis the instance that the function pointer will be compatible with, orNULLfor commands not dependent on any instance. -
pNameis the name of the command to obtain.
vkGetInstanceProcAddr itself is obtained in a platform- and loader-
specific manner.
Typically, the loader library will export this command as a function symbol,
so applications can link against the loader library, or load it dynamically
and look up the symbol using platform-specific APIs.
The table below defines the various use cases for
vkGetInstanceProcAddr and expected return value (“fp” is “function
pointer”) for each case.
The returned function pointer is of type PFN_vkVoidFunction, and must be cast to the type of the command being queried.
instance |
pName |
return value |
|---|---|---|
* |
|
undefined |
invalid instance |
* |
undefined |
|
fp |
|
|
fp |
|
|
fp |
|
|
fp |
|
|
* (any |
|
instance |
core Vulkan command |
fp1 |
instance |
enabled instance extension commands for |
fp1 |
instance |
available device extension2 commands for |
fp1 |
instance |
* (any |
|
- 1
-
The returned function pointer must only be called with a dispatchable object (the first parameter) that is
instanceor a child ofinstance, e.g. VkInstance, VkPhysicalDevice, VkDevice, VkQueue, or VkCommandBuffer. - 2
-
An “available device extension” is a device extension supported by any physical device enumerated by
instance.
In order to support systems with multiple Vulkan implementations, the
function pointers returned by vkGetInstanceProcAddr may point to
dispatch code that calls a different real implementation for different
VkDevice objects or their child objects.
The overhead of the internal dispatch for VkDevice objects can be
avoided by obtaining device-specific function pointers for any commands that
use a device or device-child object as their dispatchable object.
Such function pointers can be obtained with the command:
PFN_vkVoidFunction vkGetDeviceProcAddr(
VkDevice device,
const char* pName);
The table below defines the various use cases for vkGetDeviceProcAddr
and expected return value for each case.
The returned function pointer is of type PFN_vkVoidFunction, and must
be cast to the type of the command being queried.
The function pointer must only be called with a dispatchable object (the
first parameter) that is device or a child of device.
device |
pName |
return value |
|---|---|---|
|
* |
undefined |
invalid device |
* |
undefined |
device |
|
undefined |
device |
core device-level Vulkan command |
fp |
device |
enabled device extension commands |
fp |
device |
* (any |
|
The definition of PFN_vkVoidFunction is:
typedef void (VKAPI_PTR *PFN_vkVoidFunction)(void);
3.1.1. Extending Physical Device Core Functionality
New core physical-device-level functionality can be used when the physical-device version is greater than or equal to the version of Vulkan that added the new functionality. The Vulkan version supported by a physical device can be obtained by calling vkGetPhysicalDeviceProperties.
3.1.2. Extending Physical Device From Device Extensions
When the VK_KHR_get_physical_device_properties2 extension is enabled,
or when both the instance and the physical-device versions are at least 1.1,
physical-device-level functionality of a device extension can be used with
a physical device if the corresponding extension is enumerated by
vkEnumerateDeviceExtensionProperties for that physical device, even
before a logical device has been created.
To obtain a function pointer for a physical-device-level command from a
device extension, an application can use vkGetInstanceProcAddr.
This function pointer may point to dispatch code, which calls a different
real implementation for different VkPhysicalDevice objects.
Behavior is undefined if an extension physical-device command is called on a
physical device that does not support the extension.
Device extensions may define structures that can be added to the
pNext chain of physical-device-level commands.
Behavior is undefined if such an extension structure is passed to a
physical-device-level command for a physical device that does not support
the extension.
3.2. Instances
There is no global state in Vulkan and all per-application state is stored
in a VkInstance object.
Creating a VkInstance object initializes the Vulkan library and allows
the application to pass information about itself to the implementation.
Instances are represented by VkInstance handles:
VK_DEFINE_HANDLE(VkInstance)
The version of Vulkan that is supported by an instance may be different than the version of Vulkan supported by a device or physical device. To query properties that can be used in creating an instance, call:
VkResult vkEnumerateInstanceVersion(
uint32_t* pApiVersion);
-
pApiVersionpoints to auint32_t, which is the version of Vulkan supported by instance-level functionality, encoded as described in the API Version Numbers and Semantics section.
To create an instance object, call:
VkResult vkCreateInstance(
const VkInstanceCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkInstance* pInstance);
-
pCreateInfopoints to an instance of VkInstanceCreateInfo controlling creation of the instance. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pInstancepoints aVkInstancehandle in which the resulting instance is returned.
vkCreateInstance verifies that the requested layers exist.
If not, vkCreateInstance will return VK_ERROR_LAYER_NOT_PRESENT.
Next vkCreateInstance verifies that the requested extensions are
supported (e.g. in the implementation or in any enabled instance layer) and
if any requested extension is not supported, vkCreateInstance must
return VK_ERROR_EXTENSION_NOT_PRESENT.
After verifying and enabling the instance layers and extensions the
VkInstance object is created and returned to the application.
If a requested extension is only supported by a layer, both the layer and
the extension need to be specified at vkCreateInstance time for the
creation to succeed.
The VkInstanceCreateInfo structure is defined as:
typedef struct VkInstanceCreateInfo {
VkStructureType sType;
const void* pNext;
VkInstanceCreateFlags flags;
const VkApplicationInfo* pApplicationInfo;
uint32_t enabledLayerCount;
const char* const* ppEnabledLayerNames;
uint32_t enabledExtensionCount;
const char* const* ppEnabledExtensionNames;
} VkInstanceCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
pApplicationInfoisNULLor a pointer to an instance ofVkApplicationInfo. If notNULL, this information helps implementations recognize behavior inherent to classes of applications. VkApplicationInfo is defined in detail below. -
enabledLayerCountis the number of global layers to enable. -
ppEnabledLayerNamesis a pointer to an array ofenabledLayerCountnull-terminated UTF-8 strings containing the names of layers to enable for the created instance. See the Layers section for further details. -
enabledExtensionCountis the number of global extensions to enable. -
ppEnabledExtensionNamesis a pointer to an array ofenabledExtensionCountnull-terminated UTF-8 strings containing the names of extensions to enable.
typedef VkFlags VkInstanceCreateFlags;
VkInstanceCreateFlags is a bitmask type for setting a mask, but is
currently reserved for future use.
When creating a Vulkan instance for which you wish to disable validation
checks, add a VkValidationFlagsEXT structure to the pNext chain
of the VkInstanceCreateInfo structure, specifying the checks to be
disabled.
typedef struct VkValidationFlagsEXT {
VkStructureType sType;
const void* pNext;
uint32_t disabledValidationCheckCount;
VkValidationCheckEXT* pDisabledValidationChecks;
} VkValidationFlagsEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
disabledValidationCheckCountis the number of checks to disable. -
pDisabledValidationChecksis a pointer to an array of VkValidationCheckEXT values specifying the validation checks to be disabled.
Possible values of elements of the
VkValidationFlagsEXT::pDisabledValidationChecks array,
specifying validation checks to be disabled, are:
typedef enum VkValidationCheckEXT {
VK_VALIDATION_CHECK_ALL_EXT = 0,
VK_VALIDATION_CHECK_SHADERS_EXT = 1,
} VkValidationCheckEXT;
-
VK_VALIDATION_CHECK_ALL_EXTspecifies that all validation checks are disabled. -
VK_VALIDATION_CHECK_SHADERS_EXTspecifies that shader validation is disabled.
The VkApplicationInfo structure is defined as:
typedef struct VkApplicationInfo {
VkStructureType sType;
const void* pNext;
const char* pApplicationName;
uint32_t applicationVersion;
const char* pEngineName;
uint32_t engineVersion;
uint32_t apiVersion;
} VkApplicationInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
pApplicationNameisNULLor is a pointer to a null-terminated UTF-8 string containing the name of the application. -
applicationVersionis an unsigned integer variable containing the developer-supplied version number of the application. -
pEngineNameisNULLor is a pointer to a null-terminated UTF-8 string containing the name of the engine (if any) used to create the application. -
engineVersionis an unsigned integer variable containing the developer-supplied version number of the engine used to create the application. -
apiVersionmust be the highest version of Vulkan that the application is designed to use, encoded as described in the API Version Numbers and Semantics section. The patch version number specified inapiVersionis ignored when creating an instance object. Only the major and minor versions of the instance must match those requested inapiVersion.
Vulkan 1.0 implementations were required to return
VK_ERROR_INCOMPATIBLE_DRIVER if apiVersion was larger than 1.0.
Implementations that support Vulkan 1.1 or later must not return
VK_ERROR_INCOMPATIBLE_DRIVER for any value of apiVersion.
|
Note
Because Vulkan 1.0 implementations may fail with
|
Implicit layers must be disabled if they do not support a version at least
as high as apiVersion.
See the "Vulkan Loader Specification and
Architecture Overview" document for additional information.
|
Note
Providing a |
To destroy an instance, call:
void vkDestroyInstance(
VkInstance instance,
const VkAllocationCallbacks* pAllocator);
-
instanceis the handle of the instance to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
4. Devices and Queues
Once Vulkan is initialized, devices and queues are the primary objects used to interact with a Vulkan implementation.
Vulkan separates the concept of physical and logical devices. A physical device usually represents a single complete implementation of Vulkan (excluding instance-level functionality) available to the host, of which there are a finite number. A logical device represents an instance of that implementation with its own state and resources independent of other logical devices.
Physical devices are represented by VkPhysicalDevice handles:
VK_DEFINE_HANDLE(VkPhysicalDevice)
4.1. Physical Devices
To retrieve a list of physical device objects representing the physical devices installed in the system, call:
VkResult vkEnumeratePhysicalDevices(
VkInstance instance,
uint32_t* pPhysicalDeviceCount,
VkPhysicalDevice* pPhysicalDevices);
-
instanceis a handle to a Vulkan instance previously created with vkCreateInstance. -
pPhysicalDeviceCountis a pointer to an integer related to the number of physical devices available or queried, as described below. -
pPhysicalDevicesis eitherNULLor a pointer to an array ofVkPhysicalDevicehandles.
If pPhysicalDevices is NULL, then the number of physical devices
available is returned in pPhysicalDeviceCount.
Otherwise, pPhysicalDeviceCount must point to a variable set by the
user to the number of elements in the pPhysicalDevices array, and on
return the variable is overwritten with the number of handles actually
written to pPhysicalDevices.
If pPhysicalDeviceCount is less than the number of physical devices
available, at most pPhysicalDeviceCount structures will be written.
If pPhysicalDeviceCount is smaller than the number of physical devices
available, VK_INCOMPLETE will be returned instead of VK_SUCCESS,
to indicate that not all the available physical devices were returned.
To query general properties of physical devices once enumerated, call:
void vkGetPhysicalDeviceProperties(
VkPhysicalDevice physicalDevice,
VkPhysicalDeviceProperties* pProperties);
-
physicalDeviceis the handle to the physical device whose properties will be queried. -
pPropertiespoints to an instance of the VkPhysicalDeviceProperties structure, that will be filled with returned information.
The VkPhysicalDeviceProperties structure is defined as:
typedef struct VkPhysicalDeviceProperties {
uint32_t apiVersion;
uint32_t driverVersion;
uint32_t vendorID;
uint32_t deviceID;
VkPhysicalDeviceType deviceType;
char deviceName[VK_MAX_PHYSICAL_DEVICE_NAME_SIZE];
uint8_t pipelineCacheUUID[VK_UUID_SIZE];
VkPhysicalDeviceLimits limits;
VkPhysicalDeviceSparseProperties sparseProperties;
} VkPhysicalDeviceProperties;
-
apiVersionis the version of Vulkan supported by the device, encoded as described in the API Version Numbers and Semantics section. -
driverVersionis the vendor-specified version of the driver. -
vendorIDis a unique identifier for the vendor (see below) of the physical device. -
deviceIDis a unique identifier for the physical device among devices available from the vendor. -
deviceTypeis a VkPhysicalDeviceType specifying the type of device. -
deviceNameis a null-terminated UTF-8 string containing the name of the device. -
pipelineCacheUUIDis an array of sizeVK_UUID_SIZE, containing 8-bit values that represent a universally unique identifier for the device. -
limitsis the VkPhysicalDeviceLimits structure which specifies device-specific limits of the physical device. See Limits for details. -
sparsePropertiesis the VkPhysicalDeviceSparseProperties structure which specifies various sparse related properties of the physical device. See Sparse Properties for details.
|
Note
The value of |
The vendorID and deviceID fields are provided to allow
applications to adapt to device characteristics that are not adequately
exposed by other Vulkan queries.
|
Note
These may include performance profiles, hardware errata, or other characteristics. |
The vendor identified by vendorID is the entity responsible for the
most salient characteristics of the underlying implementation of the
VkPhysicalDevice being queried.
|
Note
For example, in the case of a discrete GPU implementation, this should be the GPU chipset vendor. In the case of a hardware accelerator integrated into a system-on-chip (SoC), this should be the supplier of the silicon IP used to create the accelerator. |
If the vendor has a PCI
vendor ID, the low 16 bits of vendorID must contain that PCI vendor
ID, and the remaining bits must be set to zero.
Otherwise, the value returned must be a valid Khronos vendor ID, obtained
as described in the Vulkan Documentation and
Extensions document in the section “Registering a Vendor ID with
Khronos”.
Khronos vendor IDs are allocated starting at 0x10000, to distinguish them
from the PCI vendor ID namespace.
The vendor is also responsible for the value returned in deviceID.
If the implementation is driven primarily by a PCI
device with a PCI device ID, the low 16 bits of
deviceID must contain that PCI device ID, and the remaining bits
must be set to zero.
Otherwise, the choice of what values to return may be dictated by operating
system or platform policies - but should uniquely identify both the device
version and any major configuration options (for example, core count in the
case of multicore devices).
|
Note
The same device ID should be used for all physical implementations of that device version and configuration. For example, all uses of a specific silicon IP GPU version and configuration should use the same device ID, even if those uses occur in different SoCs. |
The physical device types which may be returned in
VkPhysicalDeviceProperties::deviceType are:
typedef enum VkPhysicalDeviceType {
VK_PHYSICAL_DEVICE_TYPE_OTHER = 0,
VK_PHYSICAL_DEVICE_TYPE_INTEGRATED_GPU = 1,
VK_PHYSICAL_DEVICE_TYPE_DISCRETE_GPU = 2,
VK_PHYSICAL_DEVICE_TYPE_VIRTUAL_GPU = 3,
VK_PHYSICAL_DEVICE_TYPE_CPU = 4,
} VkPhysicalDeviceType;
-
VK_PHYSICAL_DEVICE_TYPE_OTHER- the device does not match any other available types. -
VK_PHYSICAL_DEVICE_TYPE_INTEGRATED_GPU- the device is typically one embedded in or tightly coupled with the host. -
VK_PHYSICAL_DEVICE_TYPE_DISCRETE_GPU- the device is typically a separate processor connected to the host via an interlink. -
VK_PHYSICAL_DEVICE_TYPE_VIRTUAL_GPU- the device is typically a virtual node in a virtualization environment. -
VK_PHYSICAL_DEVICE_TYPE_CPU- the device is typically running on the same processors as the host.
The physical device type is advertised for informational purposes only, and does not directly affect the operation of the system. However, the device type may correlate with other advertised properties or capabilities of the system, such as how many memory heaps there are.
To query general properties of physical devices once enumerated, call:
void vkGetPhysicalDeviceProperties2(
VkPhysicalDevice physicalDevice,
VkPhysicalDeviceProperties2* pProperties);
or the equivalent command
void vkGetPhysicalDeviceProperties2KHR(
VkPhysicalDevice physicalDevice,
VkPhysicalDeviceProperties2* pProperties);
-
physicalDeviceis the handle to the physical device whose properties will be queried. -
pPropertiespoints to an instance of the VkPhysicalDeviceProperties2 structure, that will be filled with returned information.
Each structure in pProperties and its pNext chain contain
members corresponding to properties or implementation-dependent limits.
vkGetPhysicalDeviceProperties2 writes each member to a value
indicating the value of that property or limit.
The VkPhysicalDeviceProperties2 structure is defined as:
typedef struct VkPhysicalDeviceProperties2 {
VkStructureType sType;
void* pNext;
VkPhysicalDeviceProperties properties;
} VkPhysicalDeviceProperties2;
or the equivalent
typedef VkPhysicalDeviceProperties2 VkPhysicalDeviceProperties2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
propertiesis a structure of type VkPhysicalDeviceProperties describing the properties of the physical device. This structure is written with the same values as if it were written by vkGetPhysicalDeviceProperties.
The pNext chain of this structure is used to extend the structure with
properties defined by extensions.
To query the UUID and LUID of a device, add
VkPhysicalDeviceIDProperties to the pNext chain of the
VkPhysicalDeviceProperties2 structure.
The VkPhysicalDeviceIDProperties structure is defined as:
typedef struct VkPhysicalDeviceIDProperties {
VkStructureType sType;
void* pNext;
uint8_t deviceUUID[VK_UUID_SIZE];
uint8_t driverUUID[VK_UUID_SIZE];
uint8_t deviceLUID[VK_LUID_SIZE];
uint32_t deviceNodeMask;
VkBool32 deviceLUIDValid;
} VkPhysicalDeviceIDProperties;
or the equivalent
typedef VkPhysicalDeviceIDProperties VkPhysicalDeviceIDPropertiesKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
deviceUUIDis an array of sizeVK_UUID_SIZE, containing 8-bit values that represent a universally unique identifier for the device. -
driverUUIDis an array of sizeVK_UUID_SIZE, containing 8-bit values that represent a universally unique identifier for the driver build in use by the device. -
deviceLUIDis an array of sizeVK_LUID_SIZE, containing 8-bit values that represent a locally unique identifier for the device. -
deviceNodeMaskis a bitfield identifying the node within a linked device adapter corresponding to the device. -
deviceLUIDValidis a boolean value that will beVK_TRUEifdeviceLUIDcontains a valid LUID anddeviceNodeMaskcontains a valid node mask, andVK_FALSEif they do not.
deviceUUID must be immutable for a given device across instances,
processes, driver APIs, driver versions, and system reboots.
Applications can compare the driverUUID value across instance and
process boundaries, and can make similar queries in external APIs to
determine whether they are capable of sharing memory objects and resources
using them with the device.
deviceUUID and/or driverUUID must be used to determine whether
a particular external object can be shared between driver components, where
such a restriction exists as defined in the compatibility table for the
particular object type:
If deviceLUIDValid is VK_FALSE, the contents of deviceLUID
and deviceNodeMask are undefined.
If deviceLUIDValid is VK_TRUE and Vulkan is running on the
Windows operating system, the contents of deviceLUID can be cast to
an LUID object and must be equal to the locally unique identifier of
a IDXGIAdapter1 object that corresponds to physicalDevice.
If deviceLUIDValid is VK_TRUE, deviceNodeMask must
contain exactly one bit.
If Vulkan is running on an operating system that supports the Direct3D 12
API and physicalDevice corresponds to an individual device in a linked
device adapter, deviceNodeMask identifies the Direct3D 12 node
corresponding to physicalDevice.
Otherwise, deviceNodeMask must be 1.
|
Note
Although they have identical descriptions,
VkPhysicalDeviceIDProperties:: |
|
Note
While VkPhysicalDeviceIDProperties:: |
To query properties of queues available on a physical device, call:
void vkGetPhysicalDeviceQueueFamilyProperties(
VkPhysicalDevice physicalDevice,
uint32_t* pQueueFamilyPropertyCount,
VkQueueFamilyProperties* pQueueFamilyProperties);
-
physicalDeviceis the handle to the physical device whose properties will be queried. -
pQueueFamilyPropertyCountis a pointer to an integer related to the number of queue families available or queried, as described below. -
pQueueFamilyPropertiesis eitherNULLor a pointer to an array of VkQueueFamilyProperties structures.
If pQueueFamilyProperties is NULL, then the number of queue families
available is returned in pQueueFamilyPropertyCount.
Otherwise, pQueueFamilyPropertyCount must point to a variable set by
the user to the number of elements in the pQueueFamilyProperties
array, and on return the variable is overwritten with the number of
structures actually written to pQueueFamilyProperties.
If pQueueFamilyPropertyCount is less than the number of queue families
available, at most pQueueFamilyPropertyCount structures will be
written.
The VkQueueFamilyProperties structure is defined as:
typedef struct VkQueueFamilyProperties {
VkQueueFlags queueFlags;
uint32_t queueCount;
uint32_t timestampValidBits;
VkExtent3D minImageTransferGranularity;
} VkQueueFamilyProperties;
-
queueFlagsis a bitmask of VkQueueFlagBits indicating capabilities of the queues in this queue family. -
queueCountis the unsigned integer count of queues in this queue family. -
timestampValidBitsis the unsigned integer count of meaningful bits in the timestamps written viavkCmdWriteTimestamp. The valid range for the count is 36..64 bits, or a value of 0, indicating no support for timestamps. Bits outside the valid range are guaranteed to be zeros. -
minImageTransferGranularityis the minimum granularity supported for image transfer operations on the queues in this queue family.
The value returned in minImageTransferGranularity has a unit of
compressed texel blocks for images having a block-compressed format, and a
unit of texels otherwise.
Possible values of minImageTransferGranularity are:
-
(0,0,0) which indicates that only whole mip levels must be transferred using the image transfer operations on the corresponding queues. In this case, the following restrictions apply to all offset and extent parameters of image transfer operations:
-
The
x,y, andzmembers of a VkOffset3D parameter must always be zero. -
The
width,height, anddepthmembers of a VkExtent3D parameter must always match the width, height, and depth of the image subresource corresponding to the parameter, respectively.
-
-
(Ax, Ay, Az) where Ax, Ay, and Az are all integer powers of two. In this case the following restrictions apply to all image transfer operations:
-
x,y, andzof a VkOffset3D parameter must be integer multiples of Ax, Ay, and Az, respectively. -
widthof a VkExtent3D parameter must be an integer multiple of Ax, or elsex+widthmust equal the width of the image subresource corresponding to the parameter. -
heightof a VkExtent3D parameter must be an integer multiple of Ay, or elsey+heightmust equal the height of the image subresource corresponding to the parameter. -
depthof a VkExtent3D parameter must be an integer multiple of Az, or elsez+depthmust equal the depth of the image subresource corresponding to the parameter. -
If the format of the image corresponding to the parameters is one of the block-compressed formats then for the purposes of the above calculations the granularity must be scaled up by the compressed texel block dimensions.
-
Queues supporting graphics and/or compute operations must report
(1,1,1) in minImageTransferGranularity, meaning that there are
no additional restrictions on the granularity of image transfer operations
for these queues.
Other queues supporting image transfer operations are only required to
support whole mip level transfers, thus minImageTransferGranularity
for queues belonging to such queue families may be (0,0,0).
The Device Memory section describes memory properties queried from the physical device.
For physical device feature queries see the Features chapter.
Bits which may be set in VkQueueFamilyProperties::queueFlags
indicating capabilities of queues in a queue family are:
typedef enum VkQueueFlagBits {
VK_QUEUE_GRAPHICS_BIT = 0x00000001,
VK_QUEUE_COMPUTE_BIT = 0x00000002,
VK_QUEUE_TRANSFER_BIT = 0x00000004,
VK_QUEUE_SPARSE_BINDING_BIT = 0x00000008,
VK_QUEUE_PROTECTED_BIT = 0x00000010,
} VkQueueFlagBits;
-
VK_QUEUE_GRAPHICS_BITspecifies that queues in this queue family support graphics operations. -
VK_QUEUE_COMPUTE_BITspecifies that queues in this queue family support compute operations. -
VK_QUEUE_TRANSFER_BITspecifies that queues in this queue family support transfer operations. -
VK_QUEUE_SPARSE_BINDING_BITspecifies that queues in this queue family support sparse memory management operations (see Sparse Resources). If any of the sparse resource features are enabled, then at least one queue family must support this bit. -
if
VK_QUEUE_PROTECTED_BITis set, then the queues in this queue family support theVK_DEVICE_QUEUE_CREATE_PROTECTED_BITbit. (see Protected Memory). If the protected memory physical device feature is supported, then at least one queue family of at least one physical device exposed by the implementation must support this bit.
If an implementation exposes any queue family that supports graphics operations, at least one queue family of at least one physical device exposed by the implementation must support both graphics and compute operations.
Furthermore, if the protected memory physical device feature is supported, then at least one queue family of at least one physical device exposed by the implementation must support graphics operations, compute operations, and protected memory operations.
|
Note
All commands that are allowed on a queue that supports transfer operations
are also allowed on a queue that supports either graphics or compute
operations.
Thus, if the capabilities of a queue family include
|
For further details see Queues.
typedef VkFlags VkQueueFlags;
VkQueueFlags is a bitmask type for setting a mask of zero or more
VkQueueFlagBits.
To query properties of queues available on a physical device, call:
void vkGetPhysicalDeviceQueueFamilyProperties2(
VkPhysicalDevice physicalDevice,
uint32_t* pQueueFamilyPropertyCount,
VkQueueFamilyProperties2* pQueueFamilyProperties);
or the equivalent command
void vkGetPhysicalDeviceQueueFamilyProperties2KHR(
VkPhysicalDevice physicalDevice,
uint32_t* pQueueFamilyPropertyCount,
VkQueueFamilyProperties2* pQueueFamilyProperties);
-
physicalDeviceis the handle to the physical device whose properties will be queried. -
pQueueFamilyPropertyCountis a pointer to an integer related to the number of queue families available or queried, as described in vkGetPhysicalDeviceQueueFamilyProperties. -
pQueueFamilyPropertiesis eitherNULLor a pointer to an array of VkQueueFamilyProperties2 structures.
vkGetPhysicalDeviceQueueFamilyProperties2 behaves similarly to
vkGetPhysicalDeviceQueueFamilyProperties, with the ability to return
extended information in a pNext chain of output structures.
The VkQueueFamilyProperties2 structure is defined as:
typedef struct VkQueueFamilyProperties2 {
VkStructureType sType;
void* pNext;
VkQueueFamilyProperties queueFamilyProperties;
} VkQueueFamilyProperties2;
or the equivalent
typedef VkQueueFamilyProperties2 VkQueueFamilyProperties2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
queueFamilyPropertiesis a structure of type VkQueueFamilyProperties which is populated with the same values as in vkGetPhysicalDeviceQueueFamilyProperties.
4.2. Devices
Device objects represent logical connections to physical devices. Each device exposes a number of queue families each having one or more queues. All queues in a queue family support the same operations.
As described in Physical Devices, a Vulkan application will first query for all physical devices in a system. Each physical device can then be queried for its capabilities, including its queue and queue family properties. Once an acceptable physical device is identified, an application will create a corresponding logical device. An application must create a separate logical device for each physical device it will use. The created logical device is then the primary interface to the physical device.
How to enumerate the physical devices in a system and query those physical devices for their queue family properties is described in the Physical Device Enumeration section above.
A single logical device can also be created from multiple physical devices, if those physical devices belong to the same device group. A device group is a set of physical devices that support accessing each other’s memory and recording a single command buffer that can be executed on all the physical devices. Device groups are enumerated by calling vkEnumeratePhysicalDeviceGroups, and a logical device is created from a subset of the physical devices in a device group by passing the physical devices through VkDeviceGroupDeviceCreateInfo.
To retrieve a list of the device groups present in the system, call:
VkResult vkEnumeratePhysicalDeviceGroups(
VkInstance instance,
uint32_t* pPhysicalDeviceGroupCount,
VkPhysicalDeviceGroupProperties* pPhysicalDeviceGroupProperties);
or the equivalent command
VkResult vkEnumeratePhysicalDeviceGroupsKHR(
VkInstance instance,
uint32_t* pPhysicalDeviceGroupCount,
VkPhysicalDeviceGroupProperties* pPhysicalDeviceGroupProperties);
-
instanceis a handle to a Vulkan instance previously created with vkCreateInstance. -
pPhysicalDeviceGroupCountis a pointer to an integer related to the number of device groups available or queried, as described below. -
pPhysicalDeviceGroupPropertiesis eitherNULLor a pointer to an array of VkPhysicalDeviceGroupProperties structures.
If pPhysicalDeviceGroupProperties is NULL, then the number of device
groups available is returned in pPhysicalDeviceGroupCount.
Otherwise, pPhysicalDeviceGroupCount must point to a variable set by
the user to the number of elements in the
pPhysicalDeviceGroupProperties array, and on return the variable is
overwritten with the number of structures actually written to
pPhysicalDeviceGroupProperties.
If pPhysicalDeviceGroupCount is less than the number of device groups
available, at most pPhysicalDeviceGroupCount structures will be
written.
If pPhysicalDeviceGroupCount is smaller than the number of device
groups available, VK_INCOMPLETE will be returned instead of
VK_SUCCESS, to indicate that not all the available device groups were
returned.
Every physical device must be in exactly one device group.
The VkPhysicalDeviceGroupProperties structure is defined as:
typedef struct VkPhysicalDeviceGroupProperties {
VkStructureType sType;
void* pNext;
uint32_t physicalDeviceCount;
VkPhysicalDevice physicalDevices[VK_MAX_DEVICE_GROUP_SIZE];
VkBool32 subsetAllocation;
} VkPhysicalDeviceGroupProperties;
or the equivalent
typedef VkPhysicalDeviceGroupProperties VkPhysicalDeviceGroupPropertiesKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
physicalDeviceCountis the number of physical devices in the group. -
physicalDevicesis an array of physical device handles representing all physical devices in the group. The firstphysicalDeviceCountelements of the array will be valid. -
subsetAllocationspecifies whether logical devices created from the group support allocating device memory on a subset of devices, via thedeviceMaskmember of the VkMemoryAllocateFlagsInfo. If this isVK_FALSE, then all device memory allocations are made across all physical devices in the group. IfphysicalDeviceCountis1, thensubsetAllocationmust beVK_FALSE.
4.2.1. Device Creation
Logical devices are represented by VkDevice handles:
VK_DEFINE_HANDLE(VkDevice)
A logical device is created as a connection to a physical device. To create a logical device, call:
VkResult vkCreateDevice(
VkPhysicalDevice physicalDevice,
const VkDeviceCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkDevice* pDevice);
-
physicalDevicemust be one of the device handles returned from a call tovkEnumeratePhysicalDevices(see Physical Device Enumeration). -
pCreateInfois a pointer to a VkDeviceCreateInfo structure containing information about how to create the device. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pDevicepoints to a handle in which the createdVkDeviceis returned.
vkCreateDevice verifies that extensions and features requested in the
ppEnabledExtensionNames and pEnabledFeatures members of
pCreateInfo, respectively, are supported by the implementation.
If any requested extension is not supported, vkCreateDevice must
return VK_ERROR_EXTENSION_NOT_PRESENT.
If any requested feature is not supported, vkCreateDevice must return
VK_ERROR_FEATURE_NOT_PRESENT.
Support for extensions can be checked before creating a device by querying
vkEnumerateDeviceExtensionProperties.
Support for features can similarly be checked by querying
vkGetPhysicalDeviceFeatures.
After verifying and enabling the extensions the VkDevice object is
created and returned to the application.
If a requested extension is only supported by a layer, both the layer and
the extension need to be specified at vkCreateInstance time for the
creation to succeed.
Multiple logical devices can be created from the same physical device.
Logical device creation may fail due to lack of device-specific resources
(in addition to the other errors).
If that occurs, vkCreateDevice will return
VK_ERROR_TOO_MANY_OBJECTS.
The VkDeviceCreateInfo structure is defined as:
typedef struct VkDeviceCreateInfo {
VkStructureType sType;
const void* pNext;
VkDeviceCreateFlags flags;
uint32_t queueCreateInfoCount;
const VkDeviceQueueCreateInfo* pQueueCreateInfos;
uint32_t enabledLayerCount;
const char* const* ppEnabledLayerNames;
uint32_t enabledExtensionCount;
const char* const* ppEnabledExtensionNames;
const VkPhysicalDeviceFeatures* pEnabledFeatures;
} VkDeviceCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
queueCreateInfoCountis the unsigned integer size of thepQueueCreateInfosarray. Refer to the Queue Creation section below for further details. -
pQueueCreateInfosis a pointer to an array of VkDeviceQueueCreateInfo structures describing the queues that are requested to be created along with the logical device. Refer to the Queue Creation section below for further details. -
enabledLayerCountis deprecated and ignored. -
ppEnabledLayerNamesis deprecated and ignored. See Device Layer Deprecation. -
enabledExtensionCountis the number of device extensions to enable. -
ppEnabledExtensionNamesis a pointer to an array ofenabledExtensionCountnull-terminated UTF-8 strings containing the names of extensions to enable for the created device. See the Extensions section for further details. -
pEnabledFeaturesisNULLor a pointer to a VkPhysicalDeviceFeatures structure that contains boolean indicators of all the features to be enabled. Refer to the Features section for further details.
typedef VkFlags VkDeviceCreateFlags;
VkDeviceCreateFlags is a bitmask type for setting a mask, but is
currently reserved for future use.
A logical device can be created that connects to one or more physical
devices by including a VkDeviceGroupDeviceCreateInfo structure in the
pNext chain of VkDeviceCreateInfo.
The VkDeviceGroupDeviceCreateInfo structure is defined as:
typedef struct VkDeviceGroupDeviceCreateInfo {
VkStructureType sType;
const void* pNext;
uint32_t physicalDeviceCount;
const VkPhysicalDevice* pPhysicalDevices;
} VkDeviceGroupDeviceCreateInfo;
or the equivalent
typedef VkDeviceGroupDeviceCreateInfo VkDeviceGroupDeviceCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
physicalDeviceCountis the number of elements in thepPhysicalDevicesarray. -
pPhysicalDevicesis an array of physical device handles belonging to the same device group.
The elements of the pPhysicalDevices array are an ordered list of the
physical devices that the logical device represents.
These must be a subset of a single device group, and need not be in the
same order as they were enumerated.
The order of the physical devices in the pPhysicalDevices array
determines the device index of each physical device, with element i
being assigned a device index of i.
Certain commands and structures refer to one or more physical devices by
using device indices or device masks formed using device indices.
A logical device created without using VkDeviceGroupDeviceCreateInfo,
or with physicalDeviceCount equal to zero, is equivalent to a
physicalDeviceCount of one and pPhysicalDevices pointing to the
physicalDevice parameter to vkCreateDevice.
In particular, the device index of that physical device is zero.
4.2.2. Device Use
The following is a high-level list of VkDevice uses along with
references on where to find more information:
-
Creation of queues. See the Queues section below for further details.
-
Creation and tracking of various synchronization constructs. See Synchronization and Cache Control for further details.
-
Allocating, freeing, and managing memory. See Memory Allocation and Resource Creation for further details.
-
Creation and destruction of command buffers and command buffer pools. See Command Buffers for further details.
-
Creation, destruction, and management of graphics state. See Pipelines and Resource Descriptors, among others, for further details.
4.2.3. Lost Device
A logical device may become lost for a number of implementation-specific reasons, indicating that pending and future command execution may fail and cause resources and backing memory to become undefined.
|
Note
Typical reasons for device loss will include things like execution timing out (to prevent denial of service), power management events, platform resource management, or implementation errors. |
When this happens, certain commands will return VK_ERROR_DEVICE_LOST
(see Error Codes for a list of such commands).
After any such event, the logical device is considered lost.
It is not possible to reset the logical device to a non-lost state, however
the lost state is specific to a logical device (VkDevice), and the
corresponding physical device (VkPhysicalDevice) may be otherwise
unaffected.
In some cases, the physical device may also be lost, and attempting to
create a new logical device will fail, returning VK_ERROR_DEVICE_LOST.
This is usually indicative of a problem with the underlying implementation,
or its connection to the host.
If the physical device has not been lost, and a new logical device is
successfully created from that physical device, it must be in the non-lost
state.
|
Note
Whilst logical device loss may be recoverable, in the case of physical device loss, it is unlikely that an application will be able to recover unless additional, unaffected physical devices exist on the system. The error is largely informational and intended only to inform the user that a platform issue has occurred, and should be investigated further. For example, underlying hardware may have developed a fault or become physically disconnected from the rest of the system. In many cases, physical device loss may cause other more serious issues such as the operating system crashing; in which case it may not be reported via the Vulkan API. |
|
Note
Undefined behavior caused by an application error may cause a device to
become lost.
However, such undefined behavior may also cause unrecoverable damage to the
process, and it is then not guaranteed that the API objects, including the
|
When a device is lost, its child objects are not implicitly destroyed and their handles are still valid. Those objects must still be destroyed before their parents or the device can be destroyed (see the Object Lifetime section). The host address space corresponding to device memory mapped using vkMapMemory is still valid, and host memory accesses to these mapped regions are still valid, but the contents are undefined. It is still legal to call any API command on the device and child objects.
Once a device is lost, command execution may fail, and commands that return
a VkResult may return VK_ERROR_DEVICE_LOST.
Commands that do not allow run-time errors must still operate correctly for
valid usage and, if applicable, return valid data.
Commands that wait indefinitely for device execution (namely
vkDeviceWaitIdle, vkQueueWaitIdle, vkWaitForFences
or vkAcquireNextImageKHR
with a maximum timeout, and vkGetQueryPoolResults with the
VK_QUERY_RESULT_WAIT_BIT bit set in flags) must return in
finite time even in the case of a lost device, and return either
VK_SUCCESS or VK_ERROR_DEVICE_LOST.
For any command that may return VK_ERROR_DEVICE_LOST, for the purpose
of determining whether a command buffer is in the
pending state, or whether resources are
considered in-use by the device, a return value of
VK_ERROR_DEVICE_LOST is equivalent to VK_SUCCESS.
The content of any external memory objects that have been exported from or
imported to a lost device become undefined.
Objects on other logical devices or in other APIs which are associated with
the same underlying memory resource as the external memory objects on the
lost device are unaffected other than their content becoming undefined.
The layout of subresources of images on other logical devices that are bound
to VkDeviceMemory objects associated with the same underlying memory
resources as external memory objects on the lost device becomes
VK_IMAGE_LAYOUT_UNDEFINED.
The state of VkSemaphore objects on other logical devices created by
importing a semaphore payload with
temporary permanence which was exported from the lost device is undefined.
The state of VkSemaphore objects on other logical devices that
permanently share a semaphore payload with a VkSemaphore object on the
lost device is undefined, and remains undefined following any subsequent
signal operations.
Implementations must ensure pending and subsequently submitted wait
operations on such semaphores behave as defined in
Semaphore State Requirements For
Wait Operations for external semaphores not in a valid state for a wait
operation.
|
editing-note
TODO (piman) - I do not think we are very clear about what “in-use by the device” means. |
4.2.4. Device Destruction
To destroy a device, call:
void vkDestroyDevice(
VkDevice device,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
To ensure that no work is active on the device, vkDeviceWaitIdle can
be used to gate the destruction of the device.
Prior to destroying a device, an application is responsible for
destroying/freeing any Vulkan objects that were created using that device as
the first parameter of the corresponding vkCreate* or
vkAllocate* command.
|
Note
The lifetime of each of these objects is bound by the lifetime of the
|
4.3. Queues
4.3.1. Queue Family Properties
As discussed in the Physical Device Enumeration section above, the vkGetPhysicalDeviceQueueFamilyProperties command is used to retrieve details about the queue families and queues supported by a device.
Each index in the pQueueFamilyProperties array returned by
vkGetPhysicalDeviceQueueFamilyProperties describes a unique queue
family on that physical device.
These indices are used when creating queues, and they correspond directly
with the queueFamilyIndex that is passed to the vkCreateDevice
command via the VkDeviceQueueCreateInfo structure as described in the
Queue Creation section below.
Grouping of queue families within a physical device is implementation-dependent.
|
Note
The general expectation is that a physical device groups all queues of matching capabilities into a single family. However, while implementations should do this, it is possible that a physical device may return two separate queue families with the same capabilities. |
Once an application has identified a physical device with the queue(s) that it desires to use, it will create those queues in conjunction with a logical device. This is described in the following section.
4.3.2. Queue Creation
Creating a logical device also creates the queues associated with that
device.
The queues to create are described by a set of VkDeviceQueueCreateInfo
structures that are passed to vkCreateDevice in
pQueueCreateInfos.
Queues are represented by VkQueue handles:
VK_DEFINE_HANDLE(VkQueue)
The VkDeviceQueueCreateInfo structure is defined as:
typedef struct VkDeviceQueueCreateInfo {
VkStructureType sType;
const void* pNext;
VkDeviceQueueCreateFlags flags;
uint32_t queueFamilyIndex;
uint32_t queueCount;
const float* pQueuePriorities;
} VkDeviceQueueCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis a bitmask indicating behavior of the queue. -
queueFamilyIndexis an unsigned integer indicating the index of the queue family to create on this device. This index corresponds to the index of an element of thepQueueFamilyPropertiesarray that was returned byvkGetPhysicalDeviceQueueFamilyProperties. -
queueCountis an unsigned integer specifying the number of queues to create in the queue family indicated byqueueFamilyIndex. -
pQueuePrioritiesis an array ofqueueCountnormalized floating point values, specifying priorities of work that will be submitted to each created queue. See Queue Priority for more information.
Bits which can be set in VkDeviceQueueCreateInfo::flags to
specify usage behavior of the queue are:
typedef enum VkDeviceQueueCreateFlagBits {
VK_DEVICE_QUEUE_CREATE_PROTECTED_BIT = 0x00000001,
} VkDeviceQueueCreateFlagBits;
-
VK_DEVICE_QUEUE_CREATE_PROTECTED_BITspecifies that the device queue is a protected-capable queue. If the protected memory feature is not enabled, theVK_DEVICE_QUEUE_CREATE_PROTECTED_BITbit offlagsmust not be set.
typedef VkFlags VkDeviceQueueCreateFlags;
VkDeviceQueueCreateFlags is a bitmask type for setting a mask of zero
or more VkDeviceQueueCreateFlagBits.
A queue can be created with a system-wide priority by including a
VkDeviceQueueGlobalPriorityCreateInfoEXT structure in the pNext
chain of VkDeviceQueueCreateInfo.
The VkDeviceQueueGlobalPriorityCreateInfoEXT structure is defined as:
typedef struct VkDeviceQueueGlobalPriorityCreateInfoEXT {
VkStructureType sType;
const void* pNext;
VkQueueGlobalPriorityEXT globalPriority;
} VkDeviceQueueGlobalPriorityCreateInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
globalPriorityis the system-wide priority associated to this queue as specified by VkQueueGlobalPriorityEXT
A queue created without specifying
VkDeviceQueueGlobalPriorityCreateInfoEXT will default to
VK_QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT.
Possible values of
VkDeviceQueueGlobalPriorityCreateInfoEXT::globalPriority,
specifying a system-wide priority level are:
typedef enum VkQueueGlobalPriorityEXT {
VK_QUEUE_GLOBAL_PRIORITY_LOW_EXT = 128,
VK_QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT = 256,
VK_QUEUE_GLOBAL_PRIORITY_HIGH_EXT = 512,
VK_QUEUE_GLOBAL_PRIORITY_REALTIME_EXT = 1024,
} VkQueueGlobalPriorityEXT;
Priority values are sorted in ascending order. A comparison operation on the enum values can be used to determine the priority order.
-
VK_QUEUE_GLOBAL_PRIORITY_LOW_EXTis below the system default. Useful for non-interactive tasks. -
VK_QUEUE_GLOBAL_PRIORITY_MEDIUM_EXTis the system default priority. -
VK_QUEUE_GLOBAL_PRIORITY_HIGH_EXTis above the system default. -
VK_QUEUE_GLOBAL_PRIORITY_REALTIME_EXTis the highest priority. Useful for critical tasks.
Queues with higher system priority may be allotted more processing time than queues with lower priority. An implementation may allow a higher-priority queue to starve a lower-priority queue until the higher-priority queue has no further commands to execute.
Priorities imply no ordering or scheduling constraints.
No specific guarantees are made about higher priority queues receiving more processing time or better quality of service than lower priority queues.
The global priority level of a queue takes precedence over the per-process
queue priority (VkDeviceQueueCreateInfo::pQueuePriorities).
Abuse of this feature may result in starving the rest of the system of
implementation resources.
Therefore, the driver implementation may deny requests to acquire a
priority above the default priority
(VK_QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT) if the caller does not have
sufficient privileges.
In this scenario VK_ERROR_NOT_PERMITTED_EXT is returned.
The driver implementation may fail the queue allocation request if
resources required to complete the operation have been exhausted (either by
the same process or a different process).
In this scenario VK_ERROR_INITIALIZATION_FAILED is returned.
To retrieve a handle to a VkQueue object, call:
void vkGetDeviceQueue(
VkDevice device,
uint32_t queueFamilyIndex,
uint32_t queueIndex,
VkQueue* pQueue);
-
deviceis the logical device that owns the queue. -
queueFamilyIndexis the index of the queue family to which the queue belongs. -
queueIndexis the index within this queue family of the queue to retrieve. -
pQueueis a pointer to aVkQueueobject that will be filled with the handle for the requested queue.
vkGetDeviceQueue must only be used to get queues that were created
with the flags parameter of VkDeviceQueueCreateInfo set to zero.
To get queues that were created with a non-zero flags parameter use
vkGetDeviceQueue2.
To retrieve a handle to a VkQueue object with specific
VkDeviceQueueCreateFlags creation flags, call:
void vkGetDeviceQueue2(
VkDevice device,
const VkDeviceQueueInfo2* pQueueInfo,
VkQueue* pQueue);
-
deviceis the logical device that owns the queue. -
pQueueInfopoints to an instance of the VkDeviceQueueInfo2 structure, describing the parameters used to create the device queue. -
pQueueis a pointer to aVkQueueobject that will be filled with the handle for the requested queue.
The VkDeviceQueueInfo2 structure is defined as:
typedef struct VkDeviceQueueInfo2 {
VkStructureType sType;
const void* pNext;
VkDeviceQueueCreateFlags flags;
uint32_t queueFamilyIndex;
uint32_t queueIndex;
} VkDeviceQueueInfo2;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. ThepNextchain ofVkDeviceQueueInfo2is used to provide additional image parameters tovkGetDeviceQueue2. -
flagsis a VkDeviceQueueCreateFlags value indicating the flags used to create the device queue. -
queueFamilyIndexis the index of the queue family to which the queue belongs. -
queueIndexis the index within this queue family of the queue to retrieve.
The queue returned by vkGetDeviceQueue2 must have the same
flags value from this structure as that used at device creation time
in a VkDeviceQueueCreateInfo instance.
If no matching flags were specified at device creation time then
pQueue will return VK_NULL_HANDLE.
4.3.3. Queue Family Index
The queue family index is used in multiple places in Vulkan in order to tie operations to a specific family of queues.
When retrieving a handle to the queue via vkGetDeviceQueue, the queue
family index is used to select which queue family to retrieve the
VkQueue handle from as described in the previous section.
When creating a VkCommandPool object (see
Command Pools), a queue family index is specified
in the VkCommandPoolCreateInfo structure.
Command buffers from this pool can only be submitted on queues
corresponding to this queue family.
When creating VkImage (see Images) and
VkBuffer (see Buffers) resources, a set of queue
families is included in the VkImageCreateInfo and
VkBufferCreateInfo structures to specify the queue families that can
access the resource.
When inserting a VkBufferMemoryBarrier or VkImageMemoryBarrier (see Events) a source and destination queue family index is specified to allow the ownership of a buffer or image to be transferred from one queue family to another. See the Resource Sharing section for details.
4.3.4. Queue Priority
Each queue is assigned a priority, as set in the VkDeviceQueueCreateInfo structures when creating the device. The priority of each queue is a normalized floating point value between 0.0 and 1.0, which is then translated to a discrete priority level by the implementation. Higher values indicate a higher priority, with 0.0 being the lowest priority and 1.0 being the highest.
Within the same device, queues with higher priority may be allotted more processing time than queues with lower priority. The implementation makes no guarantees with regards to ordering or scheduling among queues with the same priority, other than the constraints defined by any explicit synchronization primitives. The implementation make no guarantees with regards to queues across different devices.
An implementation may allow a higher-priority queue to starve a
lower-priority queue on the same VkDevice until the higher-priority
queue has no further commands to execute.
The relationship of queue priorities must not cause queues on one
VkDevice to starve queues on another VkDevice.
No specific guarantees are made about higher priority queues receiving more processing time or better quality of service than lower priority queues.
4.3.5. Queue Submission
Work is submitted to a queue via queue submission commands such as vkQueueSubmit. Queue submission commands define a set of queue operations to be executed by the underlying physical device, including synchronization with semaphores and fences.
Submission commands take as parameters a target queue, zero or more batches of work, and an optional fence to signal upon completion. Each batch consists of three distinct parts:
-
Zero or more semaphores to wait on before execution of the rest of the batch.
-
If present, these describe a semaphore wait operation.
-
-
Zero or more work items to execute.
-
If present, these describe a queue operation matching the work described.
-
-
Zero or more semaphores to signal upon completion of the work items.
-
If present, these describe a semaphore signal operation.
-
If a fence is present in a queue submission, it describes a fence signal operation.
All work described by a queue submission command must be submitted to the queue before the command returns.
Sparse Memory Binding
In Vulkan it is possible to sparsely bind memory to buffers and images as
described in the Sparse Resource chapter.
Sparse memory binding is a queue operation.
A queue whose flags include the VK_QUEUE_SPARSE_BINDING_BIT must be
able to support the mapping of a virtual address to a physical address on
the device.
This causes an update to the page table mappings on the device.
This update must be synchronized on a queue to avoid corrupting page table
mappings during execution of graphics commands.
By binding the sparse memory resources on queues, all commands that are
dependent on the updated bindings are synchronized to only execute after the
binding is updated.
See the Synchronization and Cache Control chapter for
how this synchronization is accomplished.
4.3.6. Queue Destruction
Queues are created along with a logical device during vkCreateDevice.
All queues associated with a logical device are destroyed when
vkDestroyDevice is called on that device.
5. Command Buffers
Command buffers are objects used to record commands which can be subsequently submitted to a device queue for execution. There are two levels of command buffers - primary command buffers, which can execute secondary command buffers, and which are submitted to queues, and secondary command buffers, which can be executed by primary command buffers, and which are not directly submitted to queues.
Command buffers are represented by VkCommandBuffer handles:
VK_DEFINE_HANDLE(VkCommandBuffer)
Recorded commands include commands to bind pipelines and descriptor sets to the command buffer, commands to modify dynamic state, commands to draw (for graphics rendering), commands to dispatch (for compute), commands to execute secondary command buffers (for primary command buffers only), commands to copy buffers and images, and other commands.
Each command buffer manages state independently of other command buffers. There is no inheritance of state across primary and secondary command buffers, or between secondary command buffers. When a command buffer begins recording, all state in that command buffer is undefined. When secondary command buffer(s) are recorded to execute on a primary command buffer, the secondary command buffer inherits no state from the primary command buffer, and all state of the primary command buffer is undefined after an execute secondary command buffer command is recorded. There is one exception to this rule - if the primary command buffer is inside a render pass instance, then the render pass and subpass state is not disturbed by executing secondary command buffers. Whenever the state of a command buffer is undefined, the application must set all relevant state on the command buffer before any state dependent commands such as draws and dispatches are recorded, otherwise the behavior of executing that command buffer is undefined.
Unless otherwise specified, and without explicit synchronization, the various commands submitted to a queue via command buffers may execute in arbitrary order relative to each other, and/or concurrently. Also, the memory side-effects of those commands may not be directly visible to other commands without explicit memory dependencies. This is true within a command buffer, and across command buffers submitted to a given queue. See the synchronization chapter for information on implicit and explicit synchronization between commands.
5.1. Command Buffer Lifecycle
Each command buffer is always in one of the following states:
- Initial
-
When a command buffer is allocated, it is in the initial state. Some commands are able to reset a command buffer, or a set of command buffers, back to this state from any of the executable, recording or invalid state. Command buffers in the initial state can only be moved to the recording state, or freed.
- Recording
-
vkBeginCommandBuffer changes the state of a command buffer from the initial state to the recording state. Once a command buffer is in the recording state,
vkCmd*commands can be used to record to the command buffer. - Executable
-
vkEndCommandBuffer ends the recording of a command buffer, and moves it from the recording state to the executable state. Executable command buffers can be submitted, reset, or recorded to another command buffer.
- Pending
-
Queue submission of a command buffer changes the state of a command buffer from the executable state to the pending state. Whilst in the pending state, applications must not attempt to modify the command buffer in any way - as the device may be processing the commands recorded to it. Once execution of a command buffer completes, the command buffer reverts back to either the executable state, or the invalid state if it was recorded with
VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT. A synchronization command should be used to detect when this occurs. - Invalid
-
Some operations, such as modifying or deleting a resource that was used in a command recorded to a command buffer, will transition the state of that command buffer into the invalid state. Command buffers in the invalid state can only be reset or freed.
Any given command that operates on a command buffer has its own requirements on what state a command buffer must be in, which are detailed in the valid usage constraints for that command.
Resetting a command buffer is an operation that discards any previously recorded commands and puts a command buffer in the initial state. Resetting occurs as a result of vkResetCommandBuffer or vkResetCommandPool, or as part of vkBeginCommandBuffer (which additionally puts the command buffer in the recording state).
Secondary command buffers can be recorded to a primary command buffer via vkCmdExecuteCommands. This partially ties the lifecycle of the two command buffers together - if the primary is submitted to a queue, both the primary and any secondaries recorded to it move to the pending state. Once execution of the primary completes, so does any secondary recorded within it, and once all executions of each command buffer complete, they move to the executable state. If a secondary moves to any other state whilst it is recorded to another command buffer, the primary moves to the invalid state. A primary moving to any other state does not affect the state of the secondary. Resetting or freeing a primary command buffer removes the linkage to any secondary command buffers that were recorded to it.
5.2. Command Pools
Command pools are opaque objects that command buffer memory is allocated from, and which allow the implementation to amortize the cost of resource creation across multiple command buffers. Command pools are externally synchronized, meaning that a command pool must not be used concurrently in multiple threads. That includes use via recording commands on any command buffers allocated from the pool, as well as operations that allocate, free, and reset command buffers or the pool itself.
Command pools are represented by VkCommandPool handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkCommandPool)
To create a command pool, call:
VkResult vkCreateCommandPool(
VkDevice device,
const VkCommandPoolCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkCommandPool* pCommandPool);
-
deviceis the logical device that creates the command pool. -
pCreateInfois a pointer to an instance of the VkCommandPoolCreateInfo structure specifying the state of the command pool object. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pCommandPoolpoints to aVkCommandPoolhandle in which the created pool is returned.
The VkCommandPoolCreateInfo structure is defined as:
typedef struct VkCommandPoolCreateInfo {
VkStructureType sType;
const void* pNext;
VkCommandPoolCreateFlags flags;
uint32_t queueFamilyIndex;
} VkCommandPoolCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis a bitmask of VkCommandPoolCreateFlagBits indicating usage behavior for the pool and command buffers allocated from it. -
queueFamilyIndexdesignates a queue family as described in section Queue Family Properties. All command buffers allocated from this command pool must be submitted on queues from the same queue family.
Bits which can be set in VkCommandPoolCreateInfo::flags to
specify usage behavior for a command pool are:
typedef enum VkCommandPoolCreateFlagBits {
VK_COMMAND_POOL_CREATE_TRANSIENT_BIT = 0x00000001,
VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT = 0x00000002,
VK_COMMAND_POOL_CREATE_PROTECTED_BIT = 0x00000004,
} VkCommandPoolCreateFlagBits;
-
VK_COMMAND_POOL_CREATE_TRANSIENT_BITspecifies that command buffers allocated from the pool will be short-lived, meaning that they will be reset or freed in a relatively short timeframe. This flag may be used by the implementation to control memory allocation behavior within the pool. -
VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BITallows any command buffer allocated from a pool to be individually reset to the initial state; either by calling vkResetCommandBuffer, or via the implicit reset when calling vkBeginCommandBuffer. If this flag is not set on a pool, thenvkResetCommandBuffermust not be called for any command buffer allocated from that pool. -
VK_COMMAND_POOL_CREATE_PROTECTED_BITspecifies that command buffers allocated from the pool are protected command buffers. If the protected memory feature is not enabled, theVK_COMMAND_POOL_CREATE_PROTECTED_BITbit offlagsmust not be set.
typedef VkFlags VkCommandPoolCreateFlags;
VkCommandPoolCreateFlags is a bitmask type for setting a mask of zero
or more VkCommandPoolCreateFlagBits.
To trim a command pool, call:
void vkTrimCommandPool(
VkDevice device,
VkCommandPool commandPool,
VkCommandPoolTrimFlags flags);
or the equivalent command
void vkTrimCommandPoolKHR(
VkDevice device,
VkCommandPool commandPool,
VkCommandPoolTrimFlags flags);
-
deviceis the logical device that owns the command pool. -
commandPoolis the command pool to trim. -
flagsis reserved for future use.
Trimming a command pool recycles unused memory from the command pool back to the system. Command buffers allocated from the pool are not affected by the command.
|
Note
This command provides applications with some control over the internal memory allocations used by command pools. Unused memory normally arises from command buffers that have been recorded and later reset, such that they are no longer using the memory. On reset, a command buffer can return memory to its command pool, but the only way to release memory from a command pool to the system requires calling vkResetCommandPool, which cannot be executed while any command buffers from that pool are still in use. Subsequent recording operations into command buffers will re-use this memory but since total memory requirements fluctuate over time, unused memory can accumulate. In this situation, trimming a command pool may be useful to return unused memory back to the system, returning the total outstanding memory allocated by the pool back to a more “average” value. Implementations utilize many internal allocation strategies that make it impossible to guarantee that all unused memory is released back to the system. For instance, an implementation of a command pool may involve allocating memory in bulk from the system and sub-allocating from that memory. In such an implementation any live command buffer that holds a reference to a bulk allocation would prevent that allocation from being freed, even if only a small proportion of the bulk allocation is in use. In most cases trimming will result in a reduction in allocated but unused memory, but it does not guarantee the “ideal” behaviour. Trimming may be an expensive operation, and should not be called frequently. Trimming should be treated as a way to relieve memory pressure after application-known points when there exists enough unused memory that the cost of trimming is “worth” it. |
typedef VkFlags VkCommandPoolTrimFlags;
or the equivalent
typedef VkCommandPoolTrimFlags VkCommandPoolTrimFlagsKHR;
VkCommandPoolTrimFlags is a bitmask type for setting a mask, but is
currently reserved for future use.
To reset a command pool, call:
VkResult vkResetCommandPool(
VkDevice device,
VkCommandPool commandPool,
VkCommandPoolResetFlags flags);
-
deviceis the logical device that owns the command pool. -
commandPoolis the command pool to reset. -
flagsis a bitmask of VkCommandPoolResetFlagBits controlling the reset operation.
Resetting a command pool recycles all of the resources from all of the command buffers allocated from the command pool back to the command pool. All command buffers that have been allocated from the command pool are put in the initial state.
Any primary command buffer allocated from another VkCommandPool that
is in the recording or executable state and
has a secondary command buffer allocated from commandPool recorded
into it, becomes invalid.
Bits which can be set in vkResetCommandPool::flags to control
the reset operation are:
typedef enum VkCommandPoolResetFlagBits {
VK_COMMAND_POOL_RESET_RELEASE_RESOURCES_BIT = 0x00000001,
} VkCommandPoolResetFlagBits;
-
VK_COMMAND_POOL_RESET_RELEASE_RESOURCES_BITspecifies that resetting a command pool recycles all of the resources from the command pool back to the system.
typedef VkFlags VkCommandPoolResetFlags;
VkCommandPoolResetFlags is a bitmask type for setting a mask of zero
or more VkCommandPoolResetFlagBits.
To destroy a command pool, call:
void vkDestroyCommandPool(
VkDevice device,
VkCommandPool commandPool,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the command pool. -
commandPoolis the handle of the command pool to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
When a pool is destroyed, all command buffers allocated from the pool are freed.
Any primary command buffer allocated from another VkCommandPool that
is in the recording or executable state and
has a secondary command buffer allocated from commandPool recorded
into it, becomes invalid.
5.3. Command Buffer Allocation and Management
To allocate command buffers, call:
VkResult vkAllocateCommandBuffers(
VkDevice device,
const VkCommandBufferAllocateInfo* pAllocateInfo,
VkCommandBuffer* pCommandBuffers);
-
deviceis the logical device that owns the command pool. -
pAllocateInfois a pointer to an instance of theVkCommandBufferAllocateInfostructure describing parameters of the allocation. -
pCommandBuffersis a pointer to an array ofVkCommandBufferhandles in which the resulting command buffer objects are returned. The array must be at least the length specified by thecommandBufferCountmember ofpAllocateInfo. Each allocated command buffer begins in the initial state.
vkAllocateCommandBuffers can be used to create multiple command
buffers.
If the creation of any of those command buffers fails, the implementation
must destroy all successfully created command buffer objects from this
command, set all entries of the pCommandBuffers array to NULL and
return the error.
When command buffers are first allocated, they are in the initial state.
The VkCommandBufferAllocateInfo structure is defined as:
typedef struct VkCommandBufferAllocateInfo {
VkStructureType sType;
const void* pNext;
VkCommandPool commandPool;
VkCommandBufferLevel level;
uint32_t commandBufferCount;
} VkCommandBufferAllocateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
commandPoolis the command pool from which the command buffers are allocated. -
levelis an VkCommandBufferLevel value specifying the command buffer level. -
commandBufferCountis the number of command buffers to allocate from the pool.
Possible values of VkCommandBufferAllocateInfo::level,
specifying the command buffer level, are:
typedef enum VkCommandBufferLevel {
VK_COMMAND_BUFFER_LEVEL_PRIMARY = 0,
VK_COMMAND_BUFFER_LEVEL_SECONDARY = 1,
} VkCommandBufferLevel;
-
VK_COMMAND_BUFFER_LEVEL_PRIMARYspecifies a primary command buffer. -
VK_COMMAND_BUFFER_LEVEL_SECONDARYspecifies a secondary command buffer.
To reset command buffers, call:
VkResult vkResetCommandBuffer(
VkCommandBuffer commandBuffer,
VkCommandBufferResetFlags flags);
-
commandBufferis the command buffer to reset. The command buffer can be in any state other than pending, and is moved into the initial state. -
flagsis a bitmask of VkCommandBufferResetFlagBits controlling the reset operation.
Any primary command buffer that is in the recording or executable state and has commandBuffer recorded into
it, becomes invalid.
Bits which can be set in vkResetCommandBuffer::flags to control
the reset operation are:
typedef enum VkCommandBufferResetFlagBits {
VK_COMMAND_BUFFER_RESET_RELEASE_RESOURCES_BIT = 0x00000001,
} VkCommandBufferResetFlagBits;
-
VK_COMMAND_BUFFER_RESET_RELEASE_RESOURCES_BITspecifies that most or all memory resources currently owned by the command buffer should be returned to the parent command pool. If this flag is not set, then the command buffer may hold onto memory resources and reuse them when recording commands.commandBufferis moved to the initial state.
typedef VkFlags VkCommandBufferResetFlags;
VkCommandBufferResetFlags is a bitmask type for setting a mask of zero
or more VkCommandBufferResetFlagBits.
To free command buffers, call:
void vkFreeCommandBuffers(
VkDevice device,
VkCommandPool commandPool,
uint32_t commandBufferCount,
const VkCommandBuffer* pCommandBuffers);
-
deviceis the logical device that owns the command pool. -
commandPoolis the command pool from which the command buffers were allocated. -
commandBufferCountis the length of thepCommandBuffersarray. -
pCommandBuffersis an array of handles of command buffers to free.
Any primary command buffer that is in the recording or executable state and has any element of pCommandBuffers
recorded into it, becomes invalid.
5.4. Command Buffer Recording
To begin recording a command buffer, call:
VkResult vkBeginCommandBuffer(
VkCommandBuffer commandBuffer,
const VkCommandBufferBeginInfo* pBeginInfo);
-
commandBufferis the handle of the command buffer which is to be put in the recording state. -
pBeginInfois an instance of theVkCommandBufferBeginInfostructure, which defines additional information about how the command buffer begins recording.
The VkCommandBufferBeginInfo structure is defined as:
typedef struct VkCommandBufferBeginInfo {
VkStructureType sType;
const void* pNext;
VkCommandBufferUsageFlags flags;
const VkCommandBufferInheritanceInfo* pInheritanceInfo;
} VkCommandBufferBeginInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis a bitmask of VkCommandBufferUsageFlagBits specifying usage behavior for the command buffer. -
pInheritanceInfois a pointer to aVkCommandBufferInheritanceInfostructure, which is used ifcommandBufferis a secondary command buffer. If this is a primary command buffer, then this value is ignored.
Bits which can be set in VkCommandBufferBeginInfo::flags to
specify usage behavior for a command buffer are:
typedef enum VkCommandBufferUsageFlagBits {
VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT = 0x00000001,
VK_COMMAND_BUFFER_USAGE_RENDER_PASS_CONTINUE_BIT = 0x00000002,
VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT = 0x00000004,
} VkCommandBufferUsageFlagBits;
-
VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BITspecifies that each recording of the command buffer will only be submitted once, and the command buffer will be reset and recorded again between each submission. -
VK_COMMAND_BUFFER_USAGE_RENDER_PASS_CONTINUE_BITspecifies that a secondary command buffer is considered to be entirely inside a render pass. If this is a primary command buffer, then this bit is ignored. -
VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BITspecifies that a command buffer can be resubmitted to a queue while it is in the pending state, and recorded into multiple primary command buffers.
typedef VkFlags VkCommandBufferUsageFlags;
VkCommandBufferUsageFlags is a bitmask type for setting a mask of zero
or more VkCommandBufferUsageFlagBits.
If the command buffer is a secondary command buffer, then the
VkCommandBufferInheritanceInfo structure defines any state that will
be inherited from the primary command buffer:
typedef struct VkCommandBufferInheritanceInfo {
VkStructureType sType;
const void* pNext;
VkRenderPass renderPass;
uint32_t subpass;
VkFramebuffer framebuffer;
VkBool32 occlusionQueryEnable;
VkQueryControlFlags queryFlags;
VkQueryPipelineStatisticFlags pipelineStatistics;
} VkCommandBufferInheritanceInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
renderPassis aVkRenderPassobject defining which render passes theVkCommandBufferwill be compatible with and can be executed within. If theVkCommandBufferwill not be executed within a render pass instance,renderPassis ignored. -
subpassis the index of the subpass within the render pass instance that theVkCommandBufferwill be executed within. If theVkCommandBufferwill not be executed within a render pass instance,subpassis ignored. -
framebufferoptionally refers to theVkFramebufferobject that theVkCommandBufferwill be rendering to if it is executed within a render pass instance. It can be VK_NULL_HANDLE if the framebuffer is not known, or if theVkCommandBufferwill not be executed within a render pass instance.NoteSpecifying the exact framebuffer that the secondary command buffer will be executed with may result in better performance at command buffer execution time.
-
occlusionQueryEnablespecifies whether the command buffer can be executed while an occlusion query is active in the primary command buffer. If this isVK_TRUE, then this command buffer can be executed whether the primary command buffer has an occlusion query active or not. If this isVK_FALSE, then the primary command buffer must not have an occlusion query active. -
queryFlagsspecifies the query flags that can be used by an active occlusion query in the primary command buffer when this secondary command buffer is executed. If this value includes theVK_QUERY_CONTROL_PRECISE_BITbit, then the active query can return boolean results or actual sample counts. If this bit is not set, then the active query must not use theVK_QUERY_CONTROL_PRECISE_BITbit. -
pipelineStatisticsis a bitmask of VkQueryPipelineStatisticFlagBits specifying the set of pipeline statistics that can be counted by an active query in the primary command buffer when this secondary command buffer is executed. If this value includes a given bit, then this command buffer can be executed whether the primary command buffer has a pipeline statistics query active that includes this bit or not. If this value excludes a given bit, then the active pipeline statistics query must not be from a query pool that counts that statistic.
If VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT was not set when
creating a command buffer, that command buffer must not be submitted to a
queue whilst it is already in the pending
state.
If VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT is not set on a
secondary command buffer, that command buffer must not be used more than
once in a given primary command buffer.
|
Note
On some implementations, not using the
|
If a command buffer is in the invalid, or
executable state, and the command buffer was allocated from a command pool
with the VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT flag set,
then vkBeginCommandBuffer implicitly resets the command buffer,
behaving as if vkResetCommandBuffer had been called with
VK_COMMAND_BUFFER_RESET_RELEASE_RESOURCES_BIT not set.
After the implicit reset, commandBuffer is moved to the
recording state.
Once recording starts, an application records a sequence of commands
(vkCmd*) to set state in the command buffer, draw, dispatch, and other
commands.
Several commands can also be recorded indirectly from VkBuffer
content, see Device-Generated Commands.
To complete recording of a command buffer, call:
VkResult vkEndCommandBuffer(
VkCommandBuffer commandBuffer);
-
commandBufferis the command buffer to complete recording.
If there was an error during recording, the application will be notified by
an unsuccessful return code returned by vkEndCommandBuffer.
If the application wishes to further use the command buffer, the command
buffer must be reset.
The command buffer must have been in the recording state, and is moved to the executable state.
When a command buffer is in the executable state, it can be submitted to a queue for execution.
5.5. Command Buffer Submission
To submit command buffers to a queue, call:
VkResult vkQueueSubmit(
VkQueue queue,
uint32_t submitCount,
const VkSubmitInfo* pSubmits,
VkFence fence);
-
queueis the queue that the command buffers will be submitted to. -
submitCountis the number of elements in thepSubmitsarray. -
pSubmitsis a pointer to an array of VkSubmitInfo structures, each specifying a command buffer submission batch. -
fenceis an optional handle to a fence to be signaled once all submitted command buffers have completed execution. Iffenceis not VK_NULL_HANDLE, it defines a fence signal operation.
|
Note
Submission can be a high overhead operation, and applications should
attempt to batch work together into as few calls to |
vkQueueSubmit is a queue submission
command, with each batch defined by an element of pSubmits as an
instance of the VkSubmitInfo structure.
Batches begin execution in the order they appear in pSubmits, but may
complete out of order.
Fence and semaphore operations submitted with vkQueueSubmit have additional ordering constraints compared to other submission commands, with dependencies involving previous and subsequent queue operations. Information about these additional constraints can be found in the semaphore and fence sections of the synchronization chapter.
Details on the interaction of pWaitDstStageMask with synchronization
are described in the semaphore wait
operation section of the synchronization chapter.
The order that batches appear in pSubmits is used to determine
submission order, and thus all the
implicit ordering guarantees that respect it.
Other than these implicit ordering guarantees and any explicit synchronization primitives, these batches may overlap or
otherwise execute out of order.
If any command buffer submitted to this queue is in the
executable state, it is moved to the
pending state.
Once execution of all submissions of a command buffer complete, it moves
from the pending state, back to the
executable state.
If a command buffer was recorded with the
VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT flag, it instead moves
back to the invalid state.
If vkQueueSubmit fails, it may return
VK_ERROR_OUT_OF_HOST_MEMORY or VK_ERROR_OUT_OF_DEVICE_MEMORY.
If it does, the implementation must ensure that the state and contents of
any resources or synchronization primitives referenced by the submitted
command buffers and any semaphores referenced by pSubmits is
unaffected by the call or its failure.
If vkQueueSubmit fails in such a way that the implementation is unable
to make that guarantee, the implementation must return
VK_ERROR_DEVICE_LOST.
See Lost Device.
The VkSubmitInfo structure is defined as:
typedef struct VkSubmitInfo {
VkStructureType sType;
const void* pNext;
uint32_t waitSemaphoreCount;
const VkSemaphore* pWaitSemaphores;
const VkPipelineStageFlags* pWaitDstStageMask;
uint32_t commandBufferCount;
const VkCommandBuffer* pCommandBuffers;
uint32_t signalSemaphoreCount;
const VkSemaphore* pSignalSemaphores;
} VkSubmitInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
waitSemaphoreCountis the number of semaphores upon which to wait before executing the command buffers for the batch. -
pWaitSemaphoresis a pointer to an array of semaphores upon which to wait before the command buffers for this batch begin execution. If semaphores to wait on are provided, they define a semaphore wait operation. -
pWaitDstStageMaskis a pointer to an array of pipeline stages at which each corresponding semaphore wait will occur. -
commandBufferCountis the number of command buffers to execute in the batch. -
pCommandBuffersis a pointer to an array of command buffers to execute in the batch. -
signalSemaphoreCountis the number of semaphores to be signaled once the commands specified inpCommandBuffershave completed execution. -
pSignalSemaphoresis a pointer to an array of semaphores which will be signaled when the command buffers for this batch have completed execution. If semaphores to be signaled are provided, they define a semaphore signal operation.
The order that command buffers appear in pCommandBuffers is used to
determine submission order, and thus
all the implicit ordering guarantees that
respect it.
Other than these implicit ordering guarantees and any explicit synchronization primitives, these command buffers may overlap or
otherwise execute out of order.
To specify the values to use when waiting for and signaling semaphores whose
current payload refers to a
Direct3D 12 fence, add the VkD3D12FenceSubmitInfoKHR structure to the
pNext chain of the VkSubmitInfo structure.
The VkD3D12FenceSubmitInfoKHR structure is defined as:
typedef struct VkD3D12FenceSubmitInfoKHR {
VkStructureType sType;
const void* pNext;
uint32_t waitSemaphoreValuesCount;
const uint64_t* pWaitSemaphoreValues;
uint32_t signalSemaphoreValuesCount;
const uint64_t* pSignalSemaphoreValues;
} VkD3D12FenceSubmitInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
waitSemaphoreValuesCountis the number of semaphore wait values specified inpWaitSemaphoreValues. -
pWaitSemaphoreValuesis an array of lengthwaitSemaphoreValuesCountcontaining values for the corresponding semaphores in VkSubmitInfo::pWaitSemaphoresto wait for. -
signalSemaphoreValuesCountis the number of semaphore signal values specified inpSignalSemaphoreValues. -
pSignalSemaphoreValuesis an array of lengthsignalSemaphoreValuesCountcontaining values for the corresponding semaphores in VkSubmitInfo::pSignalSemaphoresto set when signaled.
If the semaphore in VkSubmitInfo::pWaitSemaphores or
VkSubmitInfo::pSignalSemaphores corresponding to an entry in
pWaitSemaphoreValues or pSignalSemaphoreValues respectively does
not currently have a payload
referring to a Direct3D 12 fence, the implementation must ignore the value
in the pWaitSemaphoreValues or pSignalSemaphoreValues entry.
When submitting work that operates on memory imported from a Direct3D 11
resource to a queue, the keyed mutex mechanism may be used in addition to
Vulkan semaphores to synchronize the work.
Keyed mutexes are a property of a properly created shareable Direct3D 11
resource.
They can only be used if the imported resource was created with the
D3D11_RESOURCE_MISC_SHARED_KEYEDMUTEX flag.
To acquire keyed mutexes before submitted work and/or release them after,
add a VkWin32KeyedMutexAcquireReleaseInfoKHR structure to the
pNext chain of the VkSubmitInfo structure.
The VkWin32KeyedMutexAcquireReleaseInfoKHR structure is defined as:
typedef struct VkWin32KeyedMutexAcquireReleaseInfoKHR {
VkStructureType sType;
const void* pNext;
uint32_t acquireCount;
const VkDeviceMemory* pAcquireSyncs;
const uint64_t* pAcquireKeys;
const uint32_t* pAcquireTimeouts;
uint32_t releaseCount;
const VkDeviceMemory* pReleaseSyncs;
const uint64_t* pReleaseKeys;
} VkWin32KeyedMutexAcquireReleaseInfoKHR;
-
acquireCountis the number of entries in thepAcquireSyncs,pAcquireKeys, andpAcquireTimeoutMillisecondsarrays. -
pAcquireSyncsis a pointer to an array of VkDeviceMemory objects which were imported from Direct3D 11 resources. -
pAcquireKeysis a pointer to an array of mutex key values to wait for prior to beginning the submitted work. Entries refer to the keyed mutex associated with the corresponding entries inpAcquireSyncs. -
pAcquireTimeoutMillisecondsis an array of timeout values, in millisecond units, for each acquire specified inpAcquireKeys. -
releaseCountis the number of entries in thepReleaseSyncsandpReleaseKeysarrays. -
pReleaseSyncsis a pointer to an array of VkDeviceMemory objects which were imported from Direct3D 11 resources. -
pReleaseKeysis a pointer to an array of mutex key values to set when the submitted work has completed. Entries refer to the keyed mutex associated with the corresponding entries inpReleaseSyncs.
When submitting work that operates on memory imported from a Direct3D 11
resource to a queue, the keyed mutex mechanism may be used in addition to
Vulkan semaphores to synchronize the work.
Keyed mutexes are a property of a properly created shareable Direct3D 11
resource.
They can only be used if the imported resource was created with the
D3D11_RESOURCE_MISC_SHARED_KEYEDMUTEX flag.
To acquire keyed mutexes before submitted work and/or release them after,
add a VkWin32KeyedMutexAcquireReleaseInfoNV structure to the
pNext chain of the VkSubmitInfo structure.
The VkWin32KeyedMutexAcquireReleaseInfoNV structure is defined as:
typedef struct VkWin32KeyedMutexAcquireReleaseInfoNV {
VkStructureType sType;
const void* pNext;
uint32_t acquireCount;
const VkDeviceMemory* pAcquireSyncs;
const uint64_t* pAcquireKeys;
const uint32_t* pAcquireTimeoutMilliseconds;
uint32_t releaseCount;
const VkDeviceMemory* pReleaseSyncs;
const uint64_t* pReleaseKeys;
} VkWin32KeyedMutexAcquireReleaseInfoNV;
-
acquireCountis the number of entries in thepAcquireSyncs,pAcquireKeys, andpAcquireTimeoutMillisecondsarrays. -
pAcquireSyncsis a pointer to an array of VkDeviceMemory objects which were imported from Direct3D 11 resources. -
pAcquireKeysis a pointer to an array of mutex key values to wait for prior to beginning the submitted work. Entries refer to the keyed mutex associated with the corresponding entries inpAcquireSyncs. -
pAcquireTimeoutMillisecondsis an array of timeout values, in millisecond units, for each acquire specified inpAcquireKeys. -
releaseCountis the number of entries in thepReleaseSyncsandpReleaseKeysarrays. -
pReleaseSyncsis a pointer to an array of VkDeviceMemory objects which were imported from Direct3D 11 resources. -
pReleaseKeysis a pointer to an array of mutex key values to set when the submitted work has completed. Entries refer to the keyed mutex associated with the corresponding entries inpReleaseSyncs.
If the pNext chain of VkSubmitInfo includes a
VkProtectedSubmitInfo structure, then the structure indicates whether
the batch is protected.
The VkProtectedSubmitInfo structure is defined as:
typedef struct VkProtectedSubmitInfo {
VkStructureType sType;
const void* pNext;
VkBool32 protectedSubmit;
} VkProtectedSubmitInfo;
-
protectedSubmitspecifies whether the batch is protected. IfprotectedSubmitisVK_TRUE, the batch is protected. IfprotectedSubmitisVK_FALSE, the batch is unprotected. If theVkSubmitInfo::pNextchain does not contain this structure, the batch is unprotected.
If the pNext chain of VkSubmitInfo includes a
VkDeviceGroupSubmitInfo structure, then that structure includes device
indices and masks specifying which physical devices execute semaphore
operations and command buffers.
The VkDeviceGroupSubmitInfo structure is defined as:
typedef struct VkDeviceGroupSubmitInfo {
VkStructureType sType;
const void* pNext;
uint32_t waitSemaphoreCount;
const uint32_t* pWaitSemaphoreDeviceIndices;
uint32_t commandBufferCount;
const uint32_t* pCommandBufferDeviceMasks;
uint32_t signalSemaphoreCount;
const uint32_t* pSignalSemaphoreDeviceIndices;
} VkDeviceGroupSubmitInfo;
or the equivalent
typedef VkDeviceGroupSubmitInfo VkDeviceGroupSubmitInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
waitSemaphoreCountis the number of elements in thepWaitSemaphoreDeviceIndicesarray. -
pWaitSemaphoreDeviceIndicesis an array of device indices indicating which physical device executes the semaphore wait operation in the corresponding element of VkSubmitInfo::pWaitSemaphores. -
commandBufferCountis the number of elements in thepCommandBufferDeviceMasksarray. -
pCommandBufferDeviceMasksis an array of device masks indicating which physical devices execute the command buffer in the corresponding element of VkSubmitInfo::pCommandBuffers. A physical device executes the command buffer if the corresponding bit is set in the mask. -
signalSemaphoreCountis the number of elements in thepSignalSemaphoreDeviceIndicesarray. -
pSignalSemaphoreDeviceIndicesis an array of device indices indicating which physical device executes the semaphore signal operation in the corresponding element of VkSubmitInfo::pSignalSemaphores.
If this structure is not present, semaphore operations and command buffers execute on device index zero.
5.6. Queue Forward Progress
The application must ensure that command buffer submissions will be able to
complete without any subsequent operations by the application on any queue.
After any call to vkQueueSubmit, for every queued wait on a semaphore
there must be a prior signal of that semaphore that will not be consumed by
a different wait on the semaphore.
Command buffers in the submission can include vkCmdWaitEvents
commands that wait on events that will not be signaled by earlier commands
in the queue.
Such events must be signaled by the application using vkSetEvent, and
the vkCmdWaitEvents commands that wait upon them must not be inside a
render pass instance.
Implementations may have limits on how long the command buffer will wait,
in order to avoid interfering with progress of other clients of the device.
If the event is not signaled within these limits, results are undefined and
may include device loss.
5.7. Secondary Command Buffer Execution
A secondary command buffer must not be directly submitted to a queue. Instead, secondary command buffers are recorded to execute as part of a primary command buffer with the command:
void vkCmdExecuteCommands(
VkCommandBuffer commandBuffer,
uint32_t commandBufferCount,
const VkCommandBuffer* pCommandBuffers);
-
commandBufferis a handle to a primary command buffer that the secondary command buffers are executed in. -
commandBufferCountis the length of thepCommandBuffersarray. -
pCommandBuffersis an array of secondary command buffer handles, which are recorded to execute in the primary command buffer in the order they are listed in the array.
If any element of pCommandBuffers was not recorded with the
VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT flag, and it was recorded
into any other primary command buffer which is currently in the
executable or recording state, that primary
command buffer becomes invalid.
5.8. Command Buffer Device Mask
Each command buffer has a piece of state storing the current device mask of the command buffer. This mask controls which physical devices within the logical device all subsequent commands will execute on, including state-setting commands, action commands, and synchronization commands.
Scissor and viewport state can be set to different values on each physical device (only when set as dynamic state), and each physical device will render using its local copy of the state. Other state is shared between physical devices, such that all physical devices use the most recently set values for the state. However, when recording an action command that uses a piece of state, the most recent command that set that state must have included all physical devices that execute the action command in its current device mask.
The command buffer’s device mask is orthogonal to the
pCommandBufferDeviceMasks member of VkDeviceGroupSubmitInfo.
Commands only execute on a physical device if the device index is set in
both device masks.
If the pNext chain of VkCommandBufferBeginInfo includes a
VkDeviceGroupCommandBufferBeginInfo structure, then that structure
includes an initial device mask for the command buffer.
The VkDeviceGroupCommandBufferBeginInfo structure is defined as:
typedef struct VkDeviceGroupCommandBufferBeginInfo {
VkStructureType sType;
const void* pNext;
uint32_t deviceMask;
} VkDeviceGroupCommandBufferBeginInfo;
or the equivalent
typedef VkDeviceGroupCommandBufferBeginInfo VkDeviceGroupCommandBufferBeginInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
deviceMaskis the initial value of the command buffer’s device mask.
The initial device mask also acts as an upper bound on the set of devices that can ever be in the device mask in the command buffer.
If this structure is not present, the initial value of a command buffer’s device mask is set to include all physical devices in the logical device when the command buffer begins recording.
To update the current device mask of a command buffer, call:
void vkCmdSetDeviceMask(
VkCommandBuffer commandBuffer,
uint32_t deviceMask);
or the equivalent command
void vkCmdSetDeviceMaskKHR(
VkCommandBuffer commandBuffer,
uint32_t deviceMask);
-
commandBufferis command buffer whose current device mask is modified. -
deviceMaskis the new value of the current device mask.
deviceMask is used to filter out subsequent commands from executing on
all physical devices whose bit indices are not set in the mask.
6. Synchronization and Cache Control
Synchronization of access to resources is primarily the responsibility of the application in Vulkan. The order of execution of commands with respect to the host and other commands on the device has few implicit guarantees, and needs to be explicitly specified. Memory caches and other optimizations are also explicitly managed, requiring that the flow of data through the system is largely under application control.
Whilst some implicit guarantees exist between commands, five explicit synchronization mechanisms are exposed by Vulkan:
- Fences
-
Fences can be used to communicate to the host that execution of some task on the device has completed.
- Semaphores
-
Semaphores can be used to control resource access across multiple queues.
- Events
-
Events provide a fine-grained synchronization primitive which can be signaled either within a command buffer or by the host, and can be waited upon within a command buffer or queried on the host.
- Pipeline Barriers
-
Pipeline barriers also provide synchronization control within a command buffer, but at a single point, rather than with separate signal and wait operations.
- Render Passes
-
Render passes provide a useful synchronization framework for most rendering tasks, built upon the concepts in this chapter. Many cases that would otherwise need an application to use other synchronization primitives can be expressed more efficiently as part of a render pass.
6.1. Execution and Memory Dependencies
An operation is an arbitrary amount of work to be executed on the host, a device, or an external entity such as a presentation engine. Synchronization commands introduce explicit execution dependencies, and memory dependencies between two sets of operations defined by the command’s two synchronization scopes.
The synchronization scopes define which other operations a synchronization command is able to create execution dependencies with. Any type of operation that is not in a synchronization command’s synchronization scopes will not be included in the resulting dependency. For example, for many synchronization commands, the synchronization scopes can be limited to just operations executing in specific pipeline stages, which allows other pipeline stages to be excluded from a dependency. Other scoping options are possible, depending on the particular command.
An execution dependency is a guarantee that for two sets of operations, the first set must happen-before the second set. If an operation happens-before another operation, then the first operation must complete before the second operation is initiated. More precisely:
-
Let A and B be separate sets of operations.
-
Let S be a synchronization command.
-
Let AS and BS be the synchronization scopes of S.
-
Let A' be the intersection of sets A and AS.
-
Let B' be the intersection of sets B and BS.
-
Submitting A, S and B for execution, in that order, will result in execution dependency E between A' and B'.
-
Execution dependency E guarantees that A' happens-before B'.
An execution dependency chain is a sequence of execution dependencies that form a happens-before relation between the first dependency’s A' and the final dependency’s B'. For each consecutive pair of execution dependencies, a chain exists if the intersection of BS in the first dependency and AS in the second dependency is not an empty set. The formation of a single execution dependency from an execution dependency chain can be described by substituting the following in the description of execution dependencies:
-
Let S be a set of synchronization commands that generate an execution dependency chain.
-
Let AS be the first synchronization scope of the first command in S.
-
Let BS be the second synchronization scope of the last command in S.
|
Note
An execution dependency is inherently also multiple execution dependencies - a dependency exists between each subset of A' and each subset of B', and the same is true for execution dependency chains. For example, a synchronization command with multiple pipeline stages in its stage masks effectively generates one dependency between each source stage and each destination stage. This can be useful to think about when considering how execution chains are formed if they do not involve all parts of a synchronization command’s dependency. Similarly, any set of adjacent dependencies in an execution dependency chain can be considered an execution dependency chain in its own right. |
Execution dependencies alone are not sufficient to guarantee that values resulting from writes in one set of operations can be read from another set of operations.
Two additional types of operation are used to control memory access. Availability operations cause the values generated by specified memory write accesses to become available for future access. Any available value remains available until a subsequent write to the same memory location occurs (whether it is made available or not) or the memory is freed. Visibility operations cause any available values to become visible to specified memory accesses.
A memory dependency is an execution dependency which includes availability and visibility operations such that:
-
The first set of operations happens-before the availability operation.
-
The availability operation happens-before the visibility operation.
-
The visibility operation happens-before the second set of operations.
Once written values are made visible to a particular type of memory access, they can be read or written by that type of memory access. Most synchronization commands in Vulkan define a memory dependency.
The specific memory accesses that are made available and visible are defined by the access scopes of a memory dependency. Any type of access that is in a memory dependency’s first access scope and occurs in A' is made available. Any type of access that is in a memory dependency’s second access scope and occurs in B' has any available writes made visible to it. Any type of operation that is not in a synchronization command’s access scopes will not be included in the resulting dependency.
A memory dependency enforces availability and visibility of memory accesses and execution order between two sets of operations. Adding to the description of execution dependency chains:
-
Let a be the set of memory accesses performed by A'.
-
Let b be the set of memory accesses performed by B'.
-
Let aS be the first access scope of the first command in S.
-
Let bS be the second access scope of the last command in S.
-
Let a' be the intersection of sets a and aS.
-
Let b' be the intersection of sets b and bS.
-
Submitting A, S and B for execution, in that order, will result in a memory dependency m between A' and B'.
-
Memory dependency m guarantees that:
-
Memory writes in a' are made available.
-
Available memory writes, including those from a', are made visible to b'.
-
|
Note
Execution and memory dependencies are used to solve data hazards, i.e. to ensure that read and write operations occur in a well-defined order. Write-after-read hazards can be solved with just an execution dependency, but read-after-write and write-after-write hazards need appropriate memory dependencies to be included between them. If an application does not include dependencies to solve these hazards, the results and execution orders of memory accesses are undefined. |
6.1.1. Image Layout Transitions
Image subresources can be transitioned from one layout to another as part of a memory dependency (e.g. by using an image memory barrier). When a layout transition is specified in a memory dependency, it happens-after the availability operations in the memory dependency, and happens-before the visibility operations. Image layout transitions may perform read and write accesses on all memory bound to the image subresource range, so applications must ensure that all memory writes have been made available before a layout transition is executed. Available memory is automatically made visible to a layout transition, and writes performed by a layout transition are automatically made available.
Layout transitions always apply to a particular image subresource range, and
specify both an old layout and new layout.
If the old layout does not match the new layout, a transition occurs.
The old layout must match the current layout of the image subresource
range, with one exception.
The old layout can always be specified as VK_IMAGE_LAYOUT_UNDEFINED,
though doing so invalidates the contents of the image subresource range.
As image layout transitions may perform read and write accesses on the
memory bound to the image, if the image subresource affected by the layout
transition is bound to peer memory for any device in the current device mask
then the memory heap the bound memory comes from must support the
VK_PEER_MEMORY_FEATURE_GENERIC_SRC_BIT and
VK_PEER_MEMORY_FEATURE_GENERIC_DST_BIT capabilities as returned by
vkGetDeviceGroupPeerMemoryFeatures.
|
Note
Setting the old layout to |
|
Note
Applications must ensure that layout transitions happen-after all operations accessing the image with the old layout, and happen-before any operations that will access the image with the new layout. Layout transitions are potentially read/write operations, so not defining appropriate memory dependencies to guarantee this will result in a data race. |
Image layout transitions interact with memory aliasing.
6.1.2. Pipeline Stages
The work performed by an action
or synchronization command consists of multiple operations, which are
performed as a sequence of logically independent steps known as pipeline
stages.
The exact pipeline stages executed depend on the particular command that is
used, and current command buffer state when the command was recorded.
Drawing commands, dispatching commands,
copy commands, clear commands, and synchronization commands all execute in different sets of
pipeline stages.
Synchronization commands don’t execute in a defined
pipeline, but do execute VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT and
VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT.
|
Note
Operations performed by synchronization commands (e.g.
availability and
visibility operations) are not executed by a defined pipeline stage.
However other commands can still synchronize with them via the
|
Execution of operations across pipeline stages must adhere to implicit ordering guarantees, particularly including pipeline stage order. Otherwise, execution across pipeline stages may overlap or execute out of order with regards to other stages, unless otherwise enforced by an execution dependency.
Several of the synchronization commands include pipeline stage parameters, restricting the synchronization scopes for that command to just those stages. This allows fine grained control over the exact execution dependencies and accesses performed by action commands. Implementations should use these pipeline stages to avoid unnecessary stalls or cache flushing.
Bits which can be set, specifying pipeline stages, are:
typedef enum VkPipelineStageFlagBits {
VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT = 0x00000001,
VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT = 0x00000002,
VK_PIPELINE_STAGE_VERTEX_INPUT_BIT = 0x00000004,
VK_PIPELINE_STAGE_VERTEX_SHADER_BIT = 0x00000008,
VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT = 0x00000010,
VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT = 0x00000020,
VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT = 0x00000040,
VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT = 0x00000080,
VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT = 0x00000100,
VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT = 0x00000200,
VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT = 0x00000400,
VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT = 0x00000800,
VK_PIPELINE_STAGE_TRANSFER_BIT = 0x00001000,
VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT = 0x00002000,
VK_PIPELINE_STAGE_HOST_BIT = 0x00004000,
VK_PIPELINE_STAGE_ALL_GRAPHICS_BIT = 0x00008000,
VK_PIPELINE_STAGE_ALL_COMMANDS_BIT = 0x00010000,
VK_PIPELINE_STAGE_COMMAND_PROCESS_BIT_NVX = 0x00020000,
} VkPipelineStageFlagBits;
-
VK_PIPELINE_STAGE_TOP_OF_PIPE_BITspecifies the stage of the pipeline where any commands are initially received by the queue. -
VK_PIPELINE_STAGE_COMMAND_PROCESS_BIT_NVXspecifies the stage of the pipeline where device-side generation of commands via vkCmdProcessCommandsNVX is handled. -
VK_PIPELINE_STAGE_DRAW_INDIRECT_BITspecifies the stage of the pipeline where Draw/DispatchIndirect data structures are consumed. This stage also includes reading commands written by vkCmdProcessCommandsNVX. -
VK_PIPELINE_STAGE_VERTEX_INPUT_BITspecifies the stage of the pipeline where vertex and index buffers are consumed. -
VK_PIPELINE_STAGE_VERTEX_SHADER_BITspecifies the vertex shader stage. -
VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BITspecifies the tessellation control shader stage. -
VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BITspecifies the tessellation evaluation shader stage. -
VK_PIPELINE_STAGE_GEOMETRY_SHADER_BITspecifies the geometry shader stage. -
VK_PIPELINE_STAGE_FRAGMENT_SHADER_BITspecifies the fragment shader stage. -
VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BITspecifies the stage of the pipeline where early fragment tests (depth and stencil tests before fragment shading) are performed. This stage also includes subpass load operations for framebuffer attachments with a depth/stencil format. -
VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BITspecifies the stage of the pipeline where late fragment tests (depth and stencil tests after fragment shading) are performed. This stage also includes subpass store operations for framebuffer attachments with a depth/stencil format. -
VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BITspecifies the stage of the pipeline after blending where the final color values are output from the pipeline. This stage also includes subpass load and store operations and multisample resolve operations for framebuffer attachments with a color format. -
VK_PIPELINE_STAGE_TRANSFER_BITspecifies the execution of copy commands. This includes the operations resulting from all copy commands, clear commands (with the exception of vkCmdClearAttachments), and vkCmdCopyQueryPoolResults. -
VK_PIPELINE_STAGE_COMPUTE_SHADER_BITspecifies the execution of a compute shader. -
VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BITspecifies the final stage in the pipeline where operations generated by all commands complete execution. -
VK_PIPELINE_STAGE_HOST_BITspecifies a pseudo-stage indicating execution on the host of reads/writes of device memory. This stage is not invoked by any commands recorded in a command buffer. -
VK_PIPELINE_STAGE_ALL_GRAPHICS_BITspecifies the execution of all graphics pipeline stages, and is equivalent to the logical OR of:-
VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT -
VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT -
VK_PIPELINE_STAGE_VERTEX_INPUT_BIT -
VK_PIPELINE_STAGE_VERTEX_SHADER_BIT -
VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT -
VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT -
VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT -
VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT -
VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT -
VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT -
VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT -
VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT
-
-
VK_PIPELINE_STAGE_ALL_COMMANDS_BITis equivalent to the logical OR of every other pipeline stage flag that is supported on the queue it is used with.
|
Note
An execution dependency with only When defining a memory dependency, using only
|
typedef VkFlags VkPipelineStageFlags;
VkPipelineStageFlags is a bitmask type for setting a mask of zero or
more VkPipelineStageFlagBits.
If a synchronization command includes a source stage mask, its first synchronization scope only includes execution of the pipeline stages specified in that mask, and its first access scope only includes memory access performed by pipeline stages specified in that mask. If a synchronization command includes a destination stage mask, its second synchronization scope only includes execution of the pipeline stages specified in that mask, and its second access scope only includes memory access performed by pipeline stages specified in that mask.
|
Note
Including a particular pipeline stage in the first synchronization scope of a command implicitly includes logically earlier pipeline stages in the synchronization scope. Similarly, the second synchronization scope includes logically later pipeline stages. However, note that access scopes are not affected in this way - only the precise stages specified are considered part of each access scope. |
Certain pipeline stages are only available on queues that support a particular set of operations. The following table lists, for each pipeline stage flag, which queue capability flag must be supported by the queue. When multiple flags are enumerated in the second column of the table, it means that the pipeline stage is supported on the queue if it supports any of the listed capability flags. For further details on queue capabilities see Physical Device Enumeration and Queues.
| Pipeline stage flag | Required queue capability flag |
|---|---|
|
None required |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
None required |
|
None required |
|
|
|
None required |
|
|
Pipeline stages that execute as a result of a command logically complete execution in a specific order, such that completion of a logically later pipeline stage must not happen-before completion of a logically earlier stage. This means that including any stage in the source stage mask for a particular synchronization command also implies that any logically earlier stages are included in AS for that command.
Similarly, initiation of a logically earlier pipeline stage must not happen-after initiation of a logically later pipeline stage. Including any given stage in the destination stage mask for a particular synchronization command also implies that any logically later stages are included in BS for that command.
|
Note
Implementations may not support synchronization at every pipeline stage for every synchronization operation. If a pipeline stage that an implementation does not support synchronization for appears in a source stage mask, it may substitute any logically later stage in its place for the first synchronization scope. If a pipeline stage that an implementation does not support synchronization for appears in a destination stage mask, it may substitute any logically earlier stage in its place for the second synchronization scope. For example, if an implementation is unable to signal an event immediately after vertex shader execution is complete, it may instead signal the event after color attachment output has completed. If an implementation makes such a substitution, it must not affect the semantics of execution or memory dependencies or image and buffer memory barriers. |
The order and set of pipeline stages executed by a given command is determined by the command’s pipeline type, as described below:
For the graphics pipeline, the following stages occur in this order:
-
VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT -
VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT -
VK_PIPELINE_STAGE_VERTEX_INPUT_BIT -
VK_PIPELINE_STAGE_VERTEX_SHADER_BIT -
VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT -
VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT -
VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT -
VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT -
VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT -
VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT -
VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT -
VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT
For the compute pipeline, the following stages occur in this order:
-
VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT -
VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT -
VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT -
VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT
For the transfer pipeline, the following stages occur in this order:
-
VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT -
VK_PIPELINE_STAGE_TRANSFER_BIT -
VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT
For host operations, only one pipeline stage occurs, so no order is guaranteed:
-
VK_PIPELINE_STAGE_HOST_BIT
For the command processing pipeline, the following stages occur in this order:
-
VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT -
VK_PIPELINE_STAGE_COMMAND_PROCESS_BIT_NVX -
VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT
6.1.3. Access Types
Memory in Vulkan can be accessed from within shader invocations and via some fixed-function stages of the pipeline. The access type is a function of the descriptor type used, or how a fixed-function stage accesses memory. Each access type corresponds to a bit flag in VkAccessFlagBits.
Some synchronization commands take sets of access types as parameters to define the access scopes of a memory dependency. If a synchronization command includes a source access mask, its first access scope only includes accesses via the access types specified in that mask. Similarly, if a synchronization command includes a destination access mask, its second access scope only includes accesses via the access types specified in that mask.
Access types that can be set in an access mask include:
typedef enum VkAccessFlagBits {
VK_ACCESS_INDIRECT_COMMAND_READ_BIT = 0x00000001,
VK_ACCESS_INDEX_READ_BIT = 0x00000002,
VK_ACCESS_VERTEX_ATTRIBUTE_READ_BIT = 0x00000004,
VK_ACCESS_UNIFORM_READ_BIT = 0x00000008,
VK_ACCESS_INPUT_ATTACHMENT_READ_BIT = 0x00000010,
VK_ACCESS_SHADER_READ_BIT = 0x00000020,
VK_ACCESS_SHADER_WRITE_BIT = 0x00000040,
VK_ACCESS_COLOR_ATTACHMENT_READ_BIT = 0x00000080,
VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT = 0x00000100,
VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BIT = 0x00000200,
VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT = 0x00000400,
VK_ACCESS_TRANSFER_READ_BIT = 0x00000800,
VK_ACCESS_TRANSFER_WRITE_BIT = 0x00001000,
VK_ACCESS_HOST_READ_BIT = 0x00002000,
VK_ACCESS_HOST_WRITE_BIT = 0x00004000,
VK_ACCESS_MEMORY_READ_BIT = 0x00008000,
VK_ACCESS_MEMORY_WRITE_BIT = 0x00010000,
VK_ACCESS_COMMAND_PROCESS_READ_BIT_NVX = 0x00020000,
VK_ACCESS_COMMAND_PROCESS_WRITE_BIT_NVX = 0x00040000,
VK_ACCESS_COLOR_ATTACHMENT_READ_NONCOHERENT_BIT_EXT = 0x00080000,
} VkAccessFlagBits;
-
VK_ACCESS_INDIRECT_COMMAND_READ_BITspecifies read access to an indirect command structure read as part of an indirect drawing or dispatch command. -
VK_ACCESS_INDEX_READ_BITspecifies read access to an index buffer as part of an indexed drawing command, bound by vkCmdBindIndexBuffer. -
VK_ACCESS_VERTEX_ATTRIBUTE_READ_BITspecifies read access to a vertex buffer as part of a drawing command, bound by vkCmdBindVertexBuffers. -
VK_ACCESS_UNIFORM_READ_BITspecifies read access to a uniform buffer. -
VK_ACCESS_INPUT_ATTACHMENT_READ_BITspecifies read access to an input attachment within a render pass during fragment shading. -
VK_ACCESS_SHADER_READ_BITspecifies read access to a storage buffer, uniform texel buffer, storage texel buffer, sampled image, or storage image. -
VK_ACCESS_SHADER_WRITE_BITspecifies write access to a storage buffer, storage texel buffer, or storage image. -
VK_ACCESS_COLOR_ATTACHMENT_READ_BITspecifies read access to a color attachment, such as via blending, logic operations, or via certain subpass load operations. It does not include advanced blend operations. -
VK_ACCESS_COLOR_ATTACHMENT_READ_NONCOHERENT_BIT_EXTis similar toVK_ACCESS_COLOR_ATTACHMENT_READ_BIT, but also includes advanced blend operations. -
VK_ACCESS_COLOR_ATTACHMENT_WRITE_BITspecifies write access to a color or resolve attachment during a render pass or via certain subpass load and store operations. -
VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BITspecifies read access to a depth/stencil attachment, via depth or stencil operations or via certain subpass load operations. -
VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BITspecifies write access to a depth/stencil attachment, via depth or stencil operations or via certain subpass load and store operations. -
VK_ACCESS_TRANSFER_READ_BITspecifies read access to an image or buffer in a copy operation. -
VK_ACCESS_TRANSFER_WRITE_BITspecifies write access to an image or buffer in a clear or copy operation. -
VK_ACCESS_HOST_READ_BITspecifies read access by a host operation. Accesses of this type are not performed through a resource, but directly on memory. -
VK_ACCESS_HOST_WRITE_BITspecifies write access by a host operation. Accesses of this type are not performed through a resource, but directly on memory. -
VK_ACCESS_MEMORY_READ_BITspecifies read access via non-specific entities. These entities include the Vulkan device and host, but may also include entities external to the Vulkan device or otherwise not part of the core Vulkan pipeline. When included in a destination access mask, makes all available writes visible to all future read accesses on entities known to the Vulkan device. -
VK_ACCESS_MEMORY_WRITE_BITspecifies write access via non-specific entities. These entities include the Vulkan device and host, but may also include entities external to the Vulkan device or otherwise not part of the core Vulkan pipeline. When included in a source access mask, all writes that are performed by entities known to the Vulkan device are made available. When included in a destination access mask, makes all available writes visible to all future write accesses on entities known to the Vulkan device. -
VK_ACCESS_COMMAND_PROCESS_READ_BIT_NVXspecifies reads fromVkBufferinputs to vkCmdProcessCommandsNVX. -
VK_ACCESS_COMMAND_PROCESS_WRITE_BIT_NVXspecifies writes to the target command buffer in vkCmdProcessCommandsNVX.
Certain access types are only performed by a subset of pipeline stages. Any synchronization command that takes both stage masks and access masks uses both to define the access scopes - only the specified access types performed by the specified stages are included in the access scope. An application must not specify an access flag in a synchronization command if it does not include a pipeline stage in the corresponding stage mask that is able to perform accesses of that type. The following table lists, for each access flag, which pipeline stages can perform that type of access.
| Access flag | Supported pipeline stages |
|---|---|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
N/A |
|
N/A |
|
|
|
|
If a memory object does not have the
VK_MEMORY_PROPERTY_HOST_COHERENT_BIT property, then
vkFlushMappedMemoryRanges must be called in order to guarantee that
writes to the memory object from the host are made visible to the
VK_ACCESS_HOST_WRITE_BIT access
type, where it can be further made available to the device by
synchronization commands.
Similarly, vkInvalidateMappedMemoryRanges must be called to guarantee
that writes which are visible to the VK_ACCESS_HOST_READ_BIT
access type are made visible to host
operations.
If the memory object does have the
VK_MEMORY_PROPERTY_HOST_COHERENT_BIT property flag, writes to the
memory object from the host are automatically made visible to the
VK_ACCESS_HOST_WRITE_BIT access type.
Similarly, writes made visible to the VK_ACCESS_HOST_READ_BIT
access type are automatically made visible
to the host.
|
Note
The vkQueueSubmit command automatically guarantees that host writes flushed to
|
typedef VkFlags VkAccessFlags;
VkAccessFlags is a bitmask type for setting a mask of zero or more
VkAccessFlagBits.
6.1.4. Framebuffer Region Dependencies
Pipeline stages that operate on, or with respect to, the framebuffer are collectively the framebuffer-space pipeline stages. These stages are:
-
VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT -
VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT -
VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT -
VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT
For these pipeline stages, an execution or memory dependency from the first set of operations to the second set can either be a single framebuffer-global dependency, or split into multiple framebuffer-local dependencies. A dependency with non-framebuffer-space pipeline stages is neither framebuffer-global nor framebuffer-local.
A framebuffer region is a set of sample (x, y, layer, sample) coordinates that is a subset of the entire framebuffer.
Both synchronization scopes of a framebuffer-local dependency include only the operations performed within corresponding framebuffer regions (as defined below). No ordering guarantees are made between different framebuffer regions for a framebuffer-local dependency.
Both synchronization scopes of a framebuffer-global dependency include operations on all framebuffer-regions.
If the first synchronization scope includes operations on pixels/fragments with N samples and the second synchronization scope includes operations on pixels/fragments with M samples, where N does not equal M, then a framebuffer region containing all samples at a given (x, y, layer) coordinate in the first synchronization scope corresponds to a region containing all samples at the same coordinate in the second synchronization scope. In other words, it is a pixel granularity dependency. If N equals M, then a framebuffer region containing a single (x, y, layer, sample) coordinate in the first synchronization scope corresponds to a region containing the same sample at the same coordinate in the second synchronization scope. In other words, it is a sample granularity dependency.
|
Note
Since fragment invocations are not specified to run in any particular groupings, the size of a framebuffer region is implementation-dependent, not known to the application, and must be assumed to be no larger than specified above. |
|
Note
Practically, the pixel vs sample granularity dependency means that if an
input attachment has a different number of samples than the pipeline’s
|
If a synchronization command includes a dependencyFlags parameter, and
specifies the VK_DEPENDENCY_BY_REGION_BIT flag, then it defines
framebuffer-local dependencies for the framebuffer-space pipeline stages in
that synchronization command, for all framebuffer regions.
If no dependencyFlags parameter is included, or the
VK_DEPENDENCY_BY_REGION_BIT flag is not specified, then a
framebuffer-global dependency is specified for those stages.
The VK_DEPENDENCY_BY_REGION_BIT flag does not affect the dependencies
between non-framebuffer-space pipeline stages, nor does it affect the
dependencies between framebuffer-space and non-framebuffer-space pipeline
stages.
|
Note
Framebuffer-local dependencies are more optimal for most architectures; particularly tile-based architectures - which can keep framebuffer-regions entirely in on-chip registers and thus avoid external bandwidth across such a dependency. Including a framebuffer-global dependency in your rendering will usually force all implementations to flush data to memory, or to a higher level cache, breaking any potential locality optimizations. |
6.1.5. View-Local Dependencies
In a render pass instance that has multiview enabled, dependencies can be either view-local or view-global.
A view-local dependency only includes operations from a single source view from the source subpass in the first synchronization scope, and only includes operations from a single destination view from the destination subpass in the second synchronization scope. A view-global dependency includes all views in the view mask of the source and destination subpasses in the corresponding synchronization scopes.
If a synchronization command includes a dependencyFlags parameter and
specifies the VK_DEPENDENCY_VIEW_LOCAL_BIT flag, then it defines
view-local dependencies for that synchronization command, for all views.
If no dependencyFlags parameter is included or the
VK_DEPENDENCY_VIEW_LOCAL_BIT flag is not specified, then a view-global
dependency is specified.
6.1.6. Device-Local Dependencies
Dependencies can be either device-local or non-device-local.
A device-local dependency acts as multiple separate dependencies, one for
each physical device that executes the synchronization command, where each
dependency only includes operations from that physical device in both
synchronization scopes.
A non-device-local dependency is a single dependency where both
synchronization scopes include operations from all physical devices that
participate in the synchronization command.
For subpass dependencies, all physical devices in the
VkDeviceGroupRenderPassBeginInfo::deviceMask participate in the
dependency, and for pipeline barriers all physical devices that are set in
the command buffer’s current device mask participate in the dependency.
If a synchronization command includes a dependencyFlags parameter and
specifies the VK_DEPENDENCY_DEVICE_GROUP_BIT flag, then it defines a
non-device-local dependency for that synchronization command.
If no dependencyFlags parameter is included or the
VK_DEPENDENCY_DEVICE_GROUP_BIT flag is not specified, then it defines
device-local dependencies for that synchronization command, for all
participating physical devices.
Semaphore and event dependencies are device-local and only execute on the one physical device that performs the dependency.
6.2. Implicit Synchronization Guarantees
A small number of implicit ordering guarantees are provided by Vulkan, ensuring that the order in which commands are submitted is meaningful, and avoiding unnecessary complexity in common operations.
Submission order is a fundamental ordering in Vulkan, giving meaning to the order in which action and synchronization commands are recorded and submitted to a single queue. Explicit and implicit ordering guarantees between commands in Vulkan all work on the premise that this ordering is meaningful. This order does not itself define any execution or memory dependencies; synchronization commands and other orderings within the API use this ordering to define their scopes.
Submission order for any given set of commands is based on the order in which they were recorded to command buffers and then submitted. This order is determined as follows:
-
The initial order is determined by the order in which vkQueueSubmit commands are executed on the host, for a single queue, from first to last.
-
The order in which VkSubmitInfo structures are specified in the
pSubmitsparameter of vkQueueSubmit, from lowest index to highest. -
The order in which command buffers are specified in the
pCommandBuffersmember of VkSubmitInfo, from lowest index to highest. -
The order in which commands were recorded to a command buffer on the host, from first to last:
-
For commands recorded outside a render pass, this includes all other commands recorded outside a render pass, including vkCmdBeginRenderPass and vkCmdEndRenderPass commands; it does not directly include commands inside a render pass.
-
For commands recorded inside a render pass, this includes all other commands recorded inside the same subpass, including the vkCmdBeginRenderPass and vkCmdEndRenderPass commands that delimit the same render pass instance; it does not include commands recorded to other subpasses.
-
Action and synchronization
commands recorded to a command buffer execute the
VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT pipeline stage in
submission order - forming an implicit
execution dependency between this stage in each command.
State commands do not execute any operations on the device, instead they set the state of the command buffer when they execute on the host, in the order that they are recorded. Action commands consume the current state of the command buffer when they are recorded, and will execute state changes on the device as required to match the recorded state.
Query commands, the order of primitives passing through the graphics pipeline and image layout transitions as part of an image memory barrier provide additional guarantees based on submission order.
Execution of pipeline stages within a given command also has a loose ordering, dependent only on a single command.
6.3. Fences
Fences are a synchronization primitive that can be used to insert a dependency from a queue to the host. Fences have two states - signaled and unsignaled. A fence can be signaled as part of the execution of a queue submission command. Fences can be unsignaled on the host with vkResetFences. Fences can be waited on by the host with the vkWaitForFences command, and the current state can be queried with vkGetFenceStatus.
As with most objects in Vulkan, fences are an interface to internal data which is typically opaque to applications. This internal data is referred to as a fence’s payload.
However, in order to enable communication with agents outside of the current device, it is necessary to be able to export that payload to a commonly understood format, and subsequently import from that format as well.
The internal data of a fence may include a reference to any resources and pending work associated with signal or unsignal operations performed on that fence object. Mechanisms to import and export that internal data to and from fences are provided below. These mechanisms indirectly enable applications to share fence state between two or more fences and other synchronization primitives across process and API boundaries.
Fences are represented by VkFence handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkFence)
To create a fence, call:
VkResult vkCreateFence(
VkDevice device,
const VkFenceCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkFence* pFence);
-
deviceis the logical device that creates the fence. -
pCreateInfois a pointer to an instance of theVkFenceCreateInfostructure which contains information about how the fence is to be created. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pFencepoints to a handle in which the resulting fence object is returned.
The VkFenceCreateInfo structure is defined as:
typedef struct VkFenceCreateInfo {
VkStructureType sType;
const void* pNext;
VkFenceCreateFlags flags;
} VkFenceCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis a bitmask of VkFenceCreateFlagBits specifying the initial state and behavior of the fence.
typedef enum VkFenceCreateFlagBits {
VK_FENCE_CREATE_SIGNALED_BIT = 0x00000001,
} VkFenceCreateFlagBits;
-
VK_FENCE_CREATE_SIGNALED_BITspecifies that the fence object is created in the signaled state. Otherwise, it is created in the unsignaled state.
typedef VkFlags VkFenceCreateFlags;
VkFenceCreateFlags is a bitmask type for setting a mask of zero or
more VkFenceCreateFlagBits.
To create a fence whose payload can be exported to external handles, add
the VkExportFenceCreateInfo structure to the pNext chain of the
VkFenceCreateInfo structure.
The VkExportFenceCreateInfo structure is defined as:
typedef struct VkExportFenceCreateInfo {
VkStructureType sType;
const void* pNext;
VkExternalFenceHandleTypeFlags handleTypes;
} VkExportFenceCreateInfo;
or the equivalent
typedef VkExportFenceCreateInfo VkExportFenceCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
handleTypesis a bitmask of VkExternalFenceHandleTypeFlagBits specifying one or more fence handle types the application can export from the resulting fence. The application can request multiple handle types for the same fence.
To specify additional attributes of NT handles exported from a fence, add
the VkExportFenceWin32HandleInfoKHR structure to the pNext chain
of the VkFenceCreateInfo structure.
The VkExportFenceWin32HandleInfoKHR structure is defined as:
typedef struct VkExportFenceWin32HandleInfoKHR {
VkStructureType sType;
const void* pNext;
const SECURITY_ATTRIBUTES* pAttributes;
DWORD dwAccess;
LPCWSTR name;
} VkExportFenceWin32HandleInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
pAttributesis a pointer to a WindowsSECURITY_ATTRIBUTESstructure specifying security attributes of the handle. -
dwAccessis aDWORDspecifying access rights of the handle. -
nameis a NULL-terminated UTF-16 string to associate with the underlying synchronization primitive referenced by NT handles exported from the created fence.
If this structure is not present, or if pAttributes is set to NULL,
default security descriptor values will be used, and child processes created
by the application will not inherit the handle, as described in the MSDN
documentation for “Synchronization Object Security and Access Rights”1.
Further, if the structure is not present, the access rights will be
DXGI_SHARED_RESOURCE_READ | DXGI_SHARED_RESOURCE_WRITE
for handles of the following types:
VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BIT
To export a Windows handle representing the state of a fence, call:
VkResult vkGetFenceWin32HandleKHR(
VkDevice device,
const VkFenceGetWin32HandleInfoKHR* pGetWin32HandleInfo,
HANDLE* pHandle);
-
deviceis the logical device that created the fence being exported. -
pGetWin32HandleInfois a pointer to an instance of the VkFenceGetWin32HandleInfoKHR structure containing parameters of the export operation. -
pHandlewill return the Windows handle representing the fence state.
For handle types defined as NT handles, the handles returned by
vkGetFenceWin32HandleKHR are owned by the application.
To avoid leaking resources, the application must release ownership of them
using the CloseHandle system call when they are no longer needed.
Exporting a Windows handle from a fence may have side effects depending on the transference of the specified handle type, as described in Importing Fence Payloads.
The VkFenceGetWin32HandleInfoKHR structure is defined as:
typedef struct VkFenceGetWin32HandleInfoKHR {
VkStructureType sType;
const void* pNext;
VkFence fence;
VkExternalFenceHandleTypeFlagBits handleType;
} VkFenceGetWin32HandleInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
fenceis the fence from which state will be exported. -
handleTypeis the type of handle requested.
The properties of the handle returned depend on the value of
handleType.
See VkExternalFenceHandleTypeFlagBits for a description of the
properties of the defined external fence handle types.
To export a POSIX file descriptor representing the payload of a fence, call:
VkResult vkGetFenceFdKHR(
VkDevice device,
const VkFenceGetFdInfoKHR* pGetFdInfo,
int* pFd);
-
deviceis the logical device that created the fence being exported. -
pGetFdInfois a pointer to an instance of the VkFenceGetFdInfoKHR structure containing parameters of the export operation. -
pFdwill return the file descriptor representing the fence payload.
Each call to vkGetFenceFdKHR must create a new file descriptor and
transfer ownership of it to the application.
To avoid leaking resources, the application must release ownership of the
file descriptor when it is no longer needed.
|
Note
Ownership can be released in many ways.
For example, the application can call |
If pGetFdInfo::handleType is
VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT and the fence is signaled at
the time vkGetFenceFdKHR is called, pFd may return the value -1
instead of a valid file descriptor.
Where supported by the operating system, the implementation must set the
file descriptor to be closed automatically when an execve system call
is made.
Exporting a file descriptor from a fence may have side effects depending on the transference of the specified handle type, as described in Importing Fence State.
The VkFenceGetFdInfoKHR structure is defined as:
typedef struct VkFenceGetFdInfoKHR {
VkStructureType sType;
const void* pNext;
VkFence fence;
VkExternalFenceHandleTypeFlagBits handleType;
} VkFenceGetFdInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
fenceis the fence from which state will be exported. -
handleTypeis the type of handle requested.
The properties of the file descriptor returned depend on the value of
handleType.
See VkExternalFenceHandleTypeFlagBits for a description of the
properties of the defined external fence handle types.
To destroy a fence, call:
void vkDestroyFence(
VkDevice device,
VkFence fence,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the fence. -
fenceis the handle of the fence to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
To query the status of a fence from the host, call:
VkResult vkGetFenceStatus(
VkDevice device,
VkFence fence);
-
deviceis the logical device that owns the fence. -
fenceis the handle of the fence to query.
Upon success, vkGetFenceStatus returns the status of the fence object,
with the following return codes:
| Status | Meaning |
|---|---|
|
The fence specified by |
|
The fence specified by |
|
The device has been lost. See Lost Device. |
If a queue submission command is pending execution, then the value returned by this command may immediately be out of date.
If the device has been lost (see Lost Device),
vkGetFenceStatus may return any of the above status codes.
If the device has been lost and vkGetFenceStatus is called repeatedly,
it will eventually return either VK_SUCCESS or
VK_ERROR_DEVICE_LOST.
To set the state of fences to unsignaled from the host, call:
VkResult vkResetFences(
VkDevice device,
uint32_t fenceCount,
const VkFence* pFences);
-
deviceis the logical device that owns the fences. -
fenceCountis the number of fences to reset. -
pFencesis a pointer to an array of fence handles to reset.
If any member of pFences currently has its
payload imported with temporary
permanence, that fence’s prior permanent payload is first restored.
The remaining operations described therefore operate on the restored
payload.
When vkResetFences is executed on the host, it defines a fence unsignal operation for each fence, which resets the fence to the unsignaled state.
If any member of pFences is already in the unsignaled state when
vkResetFences is executed, then vkResetFences has no effect on
that fence.
When a fence is submitted to a queue as part of a queue submission command, it defines a memory dependency on the batches that were submitted as part of that command, and defines a fence signal operation which sets the fence to the signaled state.
The first synchronization scope includes every batch submitted in the same queue submission command. Fence signal operations that are defined by vkQueueSubmit additionally include in the first synchronization scope all commands that occur earlier in submission order.
The second synchronization scope only includes the fence signal operation.
The first access scope includes all memory access performed by the device.
The second access scope is empty.
To wait for one or more fences to enter the signaled state on the host, call:
VkResult vkWaitForFences(
VkDevice device,
uint32_t fenceCount,
const VkFence* pFences,
VkBool32 waitAll,
uint64_t timeout);
-
deviceis the logical device that owns the fences. -
fenceCountis the number of fences to wait on. -
pFencesis a pointer to an array offenceCountfence handles. -
waitAllis the condition that must be satisfied to successfully unblock the wait. IfwaitAllisVK_TRUE, then the condition is that all fences inpFencesare signaled. Otherwise, the condition is that at least one fence inpFencesis signaled. -
timeoutis the timeout period in units of nanoseconds.timeoutis adjusted to the closest value allowed by the implementation-dependent timeout accuracy, which may be substantially longer than one nanosecond, and may be longer than the requested period.
If the condition is satisfied when vkWaitForFences is called, then
vkWaitForFences returns immediately.
If the condition is not satisfied at the time vkWaitForFences is
called, then vkWaitForFences will block and wait up to timeout
nanoseconds for the condition to become satisfied.
If timeout is zero, then vkWaitForFences does not wait, but
simply returns the current state of the fences.
VK_TIMEOUT will be returned in this case if the condition is not
satisfied, even though no actual wait was performed.
If the specified timeout period expires before the condition is satisfied,
vkWaitForFences returns VK_TIMEOUT.
If the condition is satisfied before timeout nanoseconds has expired,
vkWaitForFences returns VK_SUCCESS.
If device loss occurs (see Lost Device) before
the timeout has expired, vkWaitForFences must return in finite time
with either VK_SUCCESS or VK_ERROR_DEVICE_LOST.
|
Note
While we guarantee that |
An execution dependency is defined by waiting for a fence to become signaled, either via vkWaitForFences or by polling on vkGetFenceStatus.
The first synchronization scope includes only the fence signal operation.
The second synchronization scope includes the host operations of vkWaitForFences or vkGetFenceStatus indicating that the fence has become signaled.
|
Note
Signaling a fence and waiting on the host does not guarantee that the results of memory accesses will be visible to the host, as the access scope of a memory dependency defined by a fence only includes device access. A memory barrier or other memory dependency must be used to guarantee this. See the description of host access types for more information. |
6.3.1. Alternate Methods to Signal Fences
Besides submitting a fence to a queue as part of a queue submission command, a fence may also be signaled when a particular event occurs on a device or display.
To create a fence that will be signaled when an event occurs on a device, call:
VkResult vkRegisterDeviceEventEXT(
VkDevice device,
const VkDeviceEventInfoEXT* pDeviceEventInfo,
const VkAllocationCallbacks* pAllocator,
VkFence* pFence);
-
deviceis a logical device on which the event may occur. -
pDeviceEventInfois a pointer to an instance of the VkDeviceEventInfoEXT structure describing the event of interest to the application. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pFencepoints to a handle in which the resulting fence object is returned.
The VkDeviceEventInfoEXT structure is defined as:
typedef struct VkDeviceEventInfoEXT {
VkStructureType sType;
const void* pNext;
VkDeviceEventTypeEXT deviceEvent;
} VkDeviceEventInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
deviceis a VkDeviceEventTypeEXT value specifying when the fence will be signaled.
Possible values of VkDeviceEventInfoEXT::device, specifying when
a fence will be signaled, are:
typedef enum VkDeviceEventTypeEXT {
VK_DEVICE_EVENT_TYPE_DISPLAY_HOTPLUG_EXT = 0,
} VkDeviceEventTypeEXT;
-
VK_DEVICE_EVENT_TYPE_DISPLAY_HOTPLUG_EXTspecifies that the fence is signaled when a display is plugged into or unplugged from the specified device. Applications can use this notification to determine when they need to re-enumerate the available displays on a device.
To create a fence that will be signaled when an event occurs on a VkDisplayKHR object, call:
VkResult vkRegisterDisplayEventEXT(
VkDevice device,
VkDisplayKHR display,
const VkDisplayEventInfoEXT* pDisplayEventInfo,
const VkAllocationCallbacks* pAllocator,
VkFence* pFence);
-
deviceis a logical device associated withdisplay -
displayis the display on which the event may occur. -
pDisplayEventInfois a pointer to an instance of the VkDisplayEventInfoEXT structure describing the event of interest to the application. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pFencepoints to a handle in which the resulting fence object is returned.
The VkDisplayEventInfoEXT structure is defined as:
typedef struct VkDisplayEventInfoEXT {
VkStructureType sType;
const void* pNext;
VkDisplayEventTypeEXT displayEvent;
} VkDisplayEventInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
displayEventis a VkDisplayEventTypeEXT specifying when the fence will be signaled.
Possible values of VkDisplayEventInfoEXT::displayEvent,
specifying when a fence will be signaled, are:
typedef enum VkDisplayEventTypeEXT {
VK_DISPLAY_EVENT_TYPE_FIRST_PIXEL_OUT_EXT = 0,
} VkDisplayEventTypeEXT;
-
VK_DISPLAY_EVENT_TYPE_FIRST_PIXEL_OUT_EXTspecifies that the fence is signaled when the first pixel of the next display refresh cycle leaves the display engine for the display.
6.3.2. Importing Fence Payloads
Applications can import a fence payload into an existing fence using an external fence handle. The effects of the import operation will be either temporary or permanent, as specified by the application. If the import is temporary, the fence will be restored to its permanent state the next time that fence is passed to vkResetFences.
|
Note
Restoring a fence to its prior permanent payload is a distinct operation from resetting a fence payload. See vkResetFences for more detail. |
Performing a subsequent temporary import on a fence before resetting it has
no effect on this requirement; the next unsignal of the fence must still
restore its last permanent state.
A permanent payload import behaves as if the target fence was destroyed, and
a new fence was created with the same handle but the imported payload.
Because importing a fence payload temporarily or permanently detaches the
existing payload from a fence, similar usage restrictions to those applied
to vkDestroyFence are applied to any command that imports a fence
payload.
Which of these import types is used is referred to as the import operation’s
permanence.
Each handle type supports either one or both types of permanence.
The implementation must perform the import operation by either referencing or copying the payload referred to by the specified external fence handle, depending on the handle’s type. The import method used is referred to as the handle type’s transference. When using handle types with reference transference, importing a payload to a fence adds the fence to the set of all fences sharing that payload. This set includes the fence from which the payload was exported. Fence signaling, waiting, and resetting operations performed on any fence in the set must behave as if the set were a single fence. Importing a payload using handle types with copy transference creates a duplicate copy of the payload at the time of import, but makes no further reference to it. Fence signaling, waiting, and resetting operations performed on the target of copy imports must not affect any other fence or payload.
Export operations have the same transference as the specified handle type’s import operations. Additionally, exporting a fence payload to a handle with copy transference has the same side effects on the source fence’s payload as executing a fence reset operation. If the fence was using a temporarily imported payload, the fence’s prior permanent payload will be restored.
|
Note
The tables Handle Types Supported by VkImportFenceWin32HandleInfoKHR and Handle Types Supported by VkImportFenceFdInfoKHR define the permanence and transference of each handle type. |
External synchronization allows
implementations to modify an object’s internal state, i.e. payload, without
internal synchronization.
However, for fences sharing a payload across processes, satisfying the
external synchronization requirements of VkFence parameters as if all
fences in the set were the same object is sometimes infeasible.
Satisfying valid usage constraints on the state of a fence would similarly
require impractical coordination or levels of trust between processes.
Therefore, these constraints only apply to a specific fence handle, not to
its payload.
For distinct fence objects which share a payload:
-
If multiple commands which queue a signal operation, or which unsignal a fence, are called concurrently, behavior will be as if the commands were called in an arbitrary sequential order.
-
If a queue submission command is called with a fence that is sharing a payload, and the payload is already associated with another queue command that has not yet completed execution, either one or both of the commands will cause the fence to become signaled when they complete execution.
-
If a fence payload is reset while it is associated with a queue command that has not yet completed execution, the payload will become unsignaled, but may become signaled again when the command completes execution.
-
In the preceding cases, any of the devices associated with the fences sharing the payload may be lost, or any of the queue submission or fence reset commands may return
VK_ERROR_INITIALIZATION_FAILED.
Other than these non-deterministic results, behavior is well defined. In particular:
-
The implementation must not crash or enter an internally inconsistent state where future valid Vulkan commands might cause undefined results,
-
Timeouts on future wait commands on fences sharing the payload must be effective.
|
Note
These rules allow processes to synchronize access to shared memory without trusting each other. However, such processes must still be cautious not to use the shared fence for more than synchronizing access to the shared memory. For example, a process should not use a fence with shared payload to tell when commands it submitted to a queue have completed and objects used by those commands may be destroyed, since the other process can accidentally or maliciously cause the fence to signal before the commands actually complete. |
When a fence is using an imported payload, its
VkExportFenceCreateInfo::handleTypes value is that specified
when creating the fence from which the payload was exported, rather than
that specified when creating the fence.
Additionally, VkExternalFenceProperties::exportFromImportedHandleTypes
restricts which handle types can be exported from such a fence based on the
specific handle type used to import the current payload.
Passing a fence to vkAcquireNextImageKHR is equivalent to temporarily
importing a fence payload to that fence.
|
Note
Because the exportable handle types of an imported fence correspond to its current imported payload, and vkAcquireNextImageKHR behaves the same as a temporary import operation for which the source fence is opaque to the application, applications have no way of determining whether any external handle types can be exported from a fence in this state. Therefore, applications must not attempt to export handles from fences using a temporarily imported payload from vkAcquireNextImageKHR. |
When importing a fence payload, it is the responsibility of the application
to ensure the external handles meet all valid usage requirements.
However, implementations must perform sufficient validation of external
handles to ensure that the operation results in a valid fence which will not
cause program termination, device loss, queue stalls, host thread stalls, or
corruption of other resources when used as allowed according to its import
parameters.
If the external handle provided does not meet these requirements, the
implementation must fail the fence payload import operation with the error
code VK_ERROR_INVALID_EXTERNAL_HANDLE.
To import a fence payload from a Windows handle, call:
VkResult vkImportFenceWin32HandleKHR(
VkDevice device,
const VkImportFenceWin32HandleInfoKHR* pImportFenceWin32HandleInfo);
-
deviceis the logical device that created the fence. -
pImportFenceWin32HandleInfopoints to a VkImportFenceWin32HandleInfoKHR structure specifying the fence and import parameters.
Importing a fence payload from Windows handles does not transfer ownership
of the handle to the Vulkan implementation.
For handle types defined as NT handles, the application must release
ownership using the CloseHandle system call when the handle is no
longer needed.
Applications can import the same fence payload into multiple instances of Vulkan, into the same instance from which it was exported, and multiple times into a given Vulkan instance.
The VkImportFenceWin32HandleInfoKHR structure is defined as:
typedef struct VkImportFenceWin32HandleInfoKHR {
VkStructureType sType;
const void* pNext;
VkFence fence;
VkFenceImportFlags flags;
VkExternalFenceHandleTypeFlagBits handleType;
HANDLE handle;
LPCWSTR name;
} VkImportFenceWin32HandleInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
fenceis the fence into which the state will be imported. -
flagsis a bitmask of VkFenceImportFlagBits specifying additional parameters for the fence payload import operation. -
handleTypespecifies the type ofhandle. -
handleis the external handle to import, orNULL. -
nameis the NULL-terminated UTF-16 string naming the underlying synchronization primitive to import, orNULL.
The handle types supported by handleType are:
| Handle Type | Transference | Permanence Supported |
|---|---|---|
|
Reference |
Temporary,Permanent |
|
Reference |
Temporary,Permanent |
To import a fence payload from a POSIX file descriptor, call:
VkResult vkImportFenceFdKHR(
VkDevice device,
const VkImportFenceFdInfoKHR* pImportFenceFdInfo);
-
deviceis the logical device that created the fence. -
pImportFenceFdInfopoints to a VkImportFenceFdInfoKHR structure specifying the fence and import parameters.
Importing a fence payload from a file descriptor transfers ownership of the file descriptor from the application to the Vulkan implementation. The application must not perform any operations on the file descriptor after a successful import.
Applications can import the same fence payload into multiple instances of Vulkan, into the same instance from which it was exported, and multiple times into a given Vulkan instance.
The VkImportFenceFdInfoKHR structure is defined as:
typedef struct VkImportFenceFdInfoKHR {
VkStructureType sType;
const void* pNext;
VkFence fence;
VkFenceImportFlags flags;
VkExternalFenceHandleTypeFlagBits handleType;
int fd;
} VkImportFenceFdInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
fenceis the fence into which the payload will be imported. -
flagsis a bitmask of VkFenceImportFlagBits specifying additional parameters for the fence payload import operation. -
handleTypespecifies the type offd. -
fdis the external handle to import.
The handle types supported by handleType are:
| Handle Type | Transference | Permanence Supported |
|---|---|---|
|
Reference |
Temporary,Permanent |
|
Copy |
Temporary |
If handleType is VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT, the
special value -1 for fd is treated like a valid sync file descriptor
referring to an object that has already signaled.
The import operation will succeed and the VkFence will have a
temporarily imported payload as if a valid file descriptor had been
provided.
|
Note
This special behavior for importing an invalid sync file descriptor allows
easier interoperability with other system APIs which use the convention that
an invalid sync file descriptor represents work that has already completed
and doesn’t need to be waited for.
It is consistent with the option for implementations to return a |
Bits which can be set in
VkImportFenceWin32HandleInfoKHR::flags
and
VkImportFenceFdInfoKHR::flags
specifying additional parameters of a fence import operation are:
typedef enum VkFenceImportFlagBits {
VK_FENCE_IMPORT_TEMPORARY_BIT = 0x00000001,
VK_FENCE_IMPORT_TEMPORARY_BIT_KHR = VK_FENCE_IMPORT_TEMPORARY_BIT,
} VkFenceImportFlagBits;
or the equivalent
typedef VkFenceImportFlagBits VkFenceImportFlagBitsKHR;
-
VK_FENCE_IMPORT_TEMPORARY_BITspecifies that the fence payload will be imported only temporarily, as described in Importing Fence Payloads, regardless of the permanence ofhandleType.
typedef VkFlags VkFenceImportFlags;
or the equivalent
typedef VkFenceImportFlags VkFenceImportFlagsKHR;
VkFenceImportFlags is a bitmask type for setting a mask of zero or
more VkFenceImportFlagBits.
6.4. Semaphores
Semaphores are a synchronization primitive that can be used to insert a dependency between batches submitted to queues. Semaphores have two states - signaled and unsignaled. The state of a semaphore can be signaled after execution of a batch of commands is completed. A batch can wait for a semaphore to become signaled before it begins execution, and the semaphore is also unsignaled before the batch begins execution.
As with most objects in Vulkan, semaphores are an interface to internal data which is typically opaque to applications. This internal data is referred to as a semaphore’s payload.
However, in order to enable communication with agents outside of the current device, it is necessary to be able to export that payload to a commonly understood format, and subsequently import from that format as well.
The internal data of a semaphore may include a reference to any resources and pending work associated with signal or unsignal operations performed on that semaphore object. Mechanisms to import and export that internal data to and from semaphores are provided below. These mechanisms indirectly enable applications to share semaphore state between two or more semaphores and other synchronization primitives across process and API boundaries.
Semaphores are represented by VkSemaphore handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkSemaphore)
To create a semaphore, call:
VkResult vkCreateSemaphore(
VkDevice device,
const VkSemaphoreCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkSemaphore* pSemaphore);
-
deviceis the logical device that creates the semaphore. -
pCreateInfois a pointer to an instance of theVkSemaphoreCreateInfostructure which contains information about how the semaphore is to be created. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pSemaphorepoints to a handle in which the resulting semaphore object is returned.
When created, the semaphore is in the unsignaled state.
The VkSemaphoreCreateInfo structure is defined as:
typedef struct VkSemaphoreCreateInfo {
VkStructureType sType;
const void* pNext;
VkSemaphoreCreateFlags flags;
} VkSemaphoreCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use.
typedef VkFlags VkSemaphoreCreateFlags;
VkSemaphoreCreateFlags is a bitmask type for setting a mask, but is
currently reserved for future use.
To create a semaphore whose payload can be exported to external handles,
add the VkExportSemaphoreCreateInfo structure to the pNext chain
of the VkSemaphoreCreateInfo structure.
The VkExportSemaphoreCreateInfo structure is defined as:
typedef struct VkExportSemaphoreCreateInfo {
VkStructureType sType;
const void* pNext;
VkExternalSemaphoreHandleTypeFlags handleTypes;
} VkExportSemaphoreCreateInfo;
or the equivalent
typedef VkExportSemaphoreCreateInfo VkExportSemaphoreCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
handleTypesis a bitmask of VkExternalSemaphoreHandleTypeFlagBits specifying one or more semaphore handle types the application can export from the resulting semaphore. The application can request multiple handle types for the same semaphore.
To specify additional attributes of NT handles exported from a semaphore,
add the VkExportSemaphoreWin32HandleInfoKHR structure to the
pNext chain of the VkSemaphoreCreateInfo structure.
The VkExportSemaphoreWin32HandleInfoKHR structure is defined as:
typedef struct VkExportSemaphoreWin32HandleInfoKHR {
VkStructureType sType;
const void* pNext;
const SECURITY_ATTRIBUTES* pAttributes;
DWORD dwAccess;
LPCWSTR name;
} VkExportSemaphoreWin32HandleInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
pAttributesis a pointer to a WindowsSECURITY_ATTRIBUTESstructure specifying security attributes of the handle. -
dwAccessis aDWORDspecifying access rights of the handle. -
nameis a NULL-terminated UTF-16 string to associate with the underlying synchronization primitive referenced by NT handles exported from the created semaphore.
If this structure is not present, or if pAttributes is set to NULL,
default security descriptor values will be used, and child processes created
by the application will not inherit the handle, as described in the MSDN
documentation for “Synchronization Object Security and Access Rights”1.
Further, if the structure is not present, the access rights will be
DXGI_SHARED_RESOURCE_READ | DXGI_SHARED_RESOURCE_WRITE
for handles of the following types:
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT
And
GENERIC_ALL
for handles of the following types:
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT
To export a Windows handle representing the payload of a semaphore, call:
VkResult vkGetSemaphoreWin32HandleKHR(
VkDevice device,
const VkSemaphoreGetWin32HandleInfoKHR* pGetWin32HandleInfo,
HANDLE* pHandle);
-
deviceis the logical device that created the semaphore being exported. -
pGetWin32HandleInfois a pointer to an instance of the VkSemaphoreGetWin32HandleInfoKHR structure containing parameters of the export operation. -
pHandlewill return the Windows handle representing the semaphore state.
For handle types defined as NT handles, the handles returned by
vkGetSemaphoreWin32HandleKHR are owned by the application.
To avoid leaking resources, the application must release ownership of them
using the CloseHandle system call when they are no longer needed.
Exporting a Windows handle from a semaphore may have side effects depending on the transference of the specified handle type, as described in Importing Semaphore Payloads.
The VkSemaphoreGetWin32HandleInfoKHR structure is defined as:
typedef struct VkSemaphoreGetWin32HandleInfoKHR {
VkStructureType sType;
const void* pNext;
VkSemaphore semaphore;
VkExternalSemaphoreHandleTypeFlagBits handleType;
} VkSemaphoreGetWin32HandleInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
semaphoreis the semaphore from which state will be exported. -
handleTypeis the type of handle requested.
The properties of the handle returned depend on the value of
handleType.
See VkExternalSemaphoreHandleTypeFlagBits for a description of the
properties of the defined external semaphore handle types.
To export a POSIX file descriptor representing the payload of a semaphore, call:
VkResult vkGetSemaphoreFdKHR(
VkDevice device,
const VkSemaphoreGetFdInfoKHR* pGetFdInfo,
int* pFd);
-
deviceis the logical device that created the semaphore being exported. -
pGetFdInfois a pointer to an instance of the VkSemaphoreGetFdInfoKHR structure containing parameters of the export operation. -
pFdwill return the file descriptor representing the semaphore payload.
Each call to vkGetSemaphoreFdKHR must create a new file descriptor
and transfer ownership of it to the application.
To avoid leaking resources, the application must release ownership of the
file descriptor when it is no longer needed.
|
Note
Ownership can be released in many ways.
For example, the application can call |
Where supported by the operating system, the implementation must set the
file descriptor to be closed automatically when an execve system call
is made.
Exporting a file descriptor from a semaphore may have side effects depending on the transference of the specified handle type, as described in Importing Semaphore State.
The VkSemaphoreGetFdInfoKHR structure is defined as:
typedef struct VkSemaphoreGetFdInfoKHR {
VkStructureType sType;
const void* pNext;
VkSemaphore semaphore;
VkExternalSemaphoreHandleTypeFlagBits handleType;
} VkSemaphoreGetFdInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
semaphoreis the semaphore from which state will be exported. -
handleTypeis the type of handle requested.
The properties of the file descriptor returned depend on the value of
handleType.
See VkExternalSemaphoreHandleTypeFlagBits for a description of the
properties of the defined external semaphore handle types.
To destroy a semaphore, call:
void vkDestroySemaphore(
VkDevice device,
VkSemaphore semaphore,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the semaphore. -
semaphoreis the handle of the semaphore to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
6.4.1. Semaphore Signaling
When a batch is submitted to a queue via a queue submission, and it includes semaphores to be signaled, it defines a memory dependency on the batch, and defines semaphore signal operations which set the semaphores to the signaled state.
The first synchronization scope includes every command submitted in the same batch. Semaphore signal operations that are defined by vkQueueSubmit additionally include all commands that occur earlier in submission order.
The second synchronization scope includes only the semaphore signal operation.
The first access scope includes all memory access performed by the device.
The second access scope is empty.
6.4.2. Semaphore Waiting & Unsignaling
When a batch is submitted to a queue via a queue submission, and it includes semaphores to be waited on, it defines a memory dependency between prior semaphore signal operations and the batch, and defines semaphore unsignal operations which set the semaphores to the unsignaled state.
The first synchronization scope includes all semaphore signal operations that operate on semaphores waited on in the same batch, and that happen-before the wait completes.
The second synchronization scope
includes every command submitted in the same batch.
In the case of vkQueueSubmit, the second synchronization scope is
limited to operations on the pipeline stages determined by the
destination stage mask specified
by the corresponding element of pWaitDstStageMask.
Also, in the case of vkQueueSubmit, the second synchronization scope
additionally includes all commands that occur later in
submission order.
The first access scope is empty.
The second access scope includes all memory access performed by the device.
The semaphore unsignal operation happens-after the first set of operations in the execution dependency, and happens-before the second set of operations in the execution dependency.
|
Note
Unlike fences or events, the act of waiting for a semaphore also unsignals that semaphore. If two operations are separately specified to wait for the same semaphore, and there are no other execution dependencies between those operations, behaviour is undefined. An execution dependency must be present that guarantees that the semaphore unsignal operation for the first of those waits, happens-before the semaphore is signalled again, and before the second unsignal operation. Semaphore waits and signals should thus occur in discrete 1:1 pairs. |
|
Note
A common scenario for using If an image layout transition needs to be performed on a presentable image
before it is used in a framebuffer, that can be performed as the first
operation submitted to the queue after acquiring the image, and should not
prevent other work from overlapping with the presentation operation.
For example, a
Alternatively, This barrier accomplishes a dependency chain between previous presentation
operations and subsequent color attachment output operations, with the
layout transition performed in between, and does not introduce a dependency
between previous work and any vertex processing stages.
More precisely, the semaphore signals after the presentation operation
completes, the semaphore wait stalls the
|
6.4.3. Semaphore State Requirements For Wait Operations
Before waiting on a semaphore, the application must ensure the semaphore is in a valid state for a wait operation. Specifically, when a semaphore wait and unsignal operation is submitted to a queue:
-
The semaphore must be signaled, or have an associated semaphore signal operation that is pending execution.
-
There must be no other queue waiting on the same semaphore when the operation executes.
6.4.4. Importing Semaphore Payloads
Applications can import a semaphore payload into an existing semaphore
using an external semaphore handle.
The effects of the import operation will be either temporary or permanent,
as specified by the application.
If the import is temporary, the implementation must restore the semaphore
to its prior permanent state after submitting the next semaphore wait
operation.
Performing a subsequent temporary import on a semaphore before performing a
semaphore wait has no effect on this requirement; the next wait submitted on
the semaphore must still restore its last permanent state.
A permanent payload import behaves as if the target semaphore was destroyed,
and a new semaphore was created with the same handle but the imported
payload.
Because importing a semaphore payload temporarily or permanently detaches
the existing payload from a semaphore, similar usage restrictions to those
applied to vkDestroySemaphore are applied to any command that imports
a semaphore payload.
Which of these import types is used is referred to as the import operation’s
permanence.
Each handle type supports either one or both types of permanence.
The implementation must perform the import operation by either referencing or copying the payload referred to by the specified external semaphore handle, depending on the handle’s type. The import method used is referred to as the handle type’s transference. When using handle types with reference transference, importing a payload to a semaphore adds the semaphore to the set of all semaphores sharing that payload. This set includes the semaphore from which the payload was exported. Semaphore signaling and waiting operations performed on any semaphore in the set must behave as if the set were a single semaphore. Importing a payload using handle types with copy transference creates a duplicate copy of the payload at the time of import, but makes no further reference to it. Semaphore signaling and waiting operations performed on the target of copy imports must not affect any other semaphore or payload.
Export operations have the same transference as the specified handle type’s import operations. Additionally, exporting a semaphore payload to a handle with copy transference has the same side effects on the source semaphore’s payload as executing a semaphore wait operation. If the semaphore was using a temporarily imported payload, the semaphore’s prior permanent payload will be restored.
|
Note
The tables Handle Types Supported by VkImportSemaphoreWin32HandleInfoKHR and Handle Types Supported by VkImportSemaphoreFdInfoKHR define the permanence and transference of each handle type. |
External synchronization allows
implementations to modify an object’s internal state, i.e. payload, without
internal synchronization.
However, for semaphores sharing a payload across processes, satisfying the
external synchronization requirements of VkSemaphore parameters as if
all semaphores in the set were the same object is sometimes infeasible.
Satisfying the wait operation
state requirements would similarly require impractical coordination or
levels of trust between processes.
Therefore, these constraints only apply to a specific semaphore handle, not
to its payload.
For distinct semaphore objects which share a payload, if the semaphores are
passed to separate queue submission commands concurrently, behavior will be
as if the commands were called in an arbitrary sequential order.
If the wait operation state
requirements are violated for the shared payload by a queue submission
command, or if a signal operation is queued for a shared payload that is
already signaled or has a pending signal operation, effects must be limited
to one or more of the following:
-
Returning
VK_ERROR_INITIALIZATION_FAILEDfrom the command which resulted in the violation. -
Losing the logical device on which the violation occured immediately or at a future time, resulting in a
VK_ERROR_DEVICE_LOSTerror from subsequent commands, including the one causing the violation. -
Continuing execution of the violating command or operation as if the semaphore wait completed successfully after an implementation-dependent timeout. In this case, the state of the payload becomes undefined, and future operations on semaphores sharing the payload will be subject to these same rules. The semaphore must be destroyed or have its payload replaced by an import operation to again have a well-defined state.
|
Note
These rules allow processes to synchronize access to shared memory without trusting each other. However, such processes must still be cautious not to use the shared semaphore for more than synchronizing access to the shared memory. For example, a process should not use a shared semaphore as part of an execution dependency chain that, when complete, leads to objects being destroyed, if it does not trust other processes sharing the semaphore payload. |
When a semaphore is using an imported payload, its
VkExportSemaphoreCreateInfo::handleTypes value is that specified
when creating the semaphore from which the payload was exported, rather than
that specified when creating the semaphore.
Additionally,
VkExternalSemaphoreProperties::exportFromImportedHandleTypes restricts
which handle types can be exported from such a semaphore based on the
specific handle type used to import the current payload.
Passing a semaphore to vkAcquireNextImageKHR is equivalent to
temporarily importing a semaphore payload to that semaphore.
|
Note
Because the exportable handle types of an imported semaphore correspond to its current imported payload, and vkAcquireNextImageKHR behaves the same as a temporary import operation for which the source semaphore is opaque to the application, applications have no way of determining whether any external handle types can be exported from a semaphore in this state. Therefore, applications must not attempt to export external handles from semaphores using a temporarily imported payload from vkAcquireNextImageKHR. |
When importing a semaphore payload, it is the responsibility of the
application to ensure the external handles meet all valid usage
requirements.
However, implementations must perform sufficient validation of external
handles to ensure that the operation results in a valid semaphore which will
not cause program termination, device loss, queue stalls, or corruption of
other resources when used as allowed according to its import parameters, and
excepting those side effects allowed for violations of the
valid semaphore state for wait
operations rules.
If the external handle provided does not meet these requirements, the
implementation must fail the semaphore payload import operation with the
error code VK_ERROR_INVALID_EXTERNAL_HANDLE.
To import a semaphore payload from a Windows handle, call:
VkResult vkImportSemaphoreWin32HandleKHR(
VkDevice device,
const VkImportSemaphoreWin32HandleInfoKHR* pImportSemaphoreWin32HandleInfo);
-
deviceis the logical device that created the semaphore. -
pImportSemaphoreWin32HandleInfopoints to a VkImportSemaphoreWin32HandleInfoKHR structure specifying the semaphore and import parameters.
Importing a semaphore payload from Windows handles does not transfer
ownership of the handle to the Vulkan implementation.
For handle types defined as NT handles, the application must release
ownership using the CloseHandle system call when the handle is no
longer needed.
Applications can import the same semaphore payload into multiple instances of Vulkan, into the same instance from which it was exported, and multiple times into a given Vulkan instance.
The VkImportSemaphoreWin32HandleInfoKHR structure is defined as:
typedef struct VkImportSemaphoreWin32HandleInfoKHR {
VkStructureType sType;
const void* pNext;
VkSemaphore semaphore;
VkSemaphoreImportFlags flags;
VkExternalSemaphoreHandleTypeFlagBits handleType;
HANDLE handle;
LPCWSTR name;
} VkImportSemaphoreWin32HandleInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
semaphoreis the semaphore into which the payload will be imported. -
flagsis a bitmask of VkSemaphoreImportFlagBits specifying additional parameters for the semaphore payload import operation. -
handleTypespecifies the type ofhandle. -
handleis the external handle to import, orNULL. -
nameis a NULL-terminated UTF-16 string naming the underlying synchronization primitive to import, orNULL.
The handle types supported by handleType are:
| Handle Type | Transference | Permanence Supported |
|---|---|---|
|
Reference |
Temporary,Permanent |
|
Reference |
Temporary,Permanent |
|
Reference |
Temporary,Permanent |
To import a semaphore payload from a POSIX file descriptor, call:
VkResult vkImportSemaphoreFdKHR(
VkDevice device,
const VkImportSemaphoreFdInfoKHR* pImportSemaphoreFdInfo);
-
deviceis the logical device that created the semaphore. -
pImportSemaphoreFdInfopoints to a VkImportSemaphoreFdInfoKHR structure specifying the semaphore and import parameters.
Importing a semaphore payload from a file descriptor transfers ownership of the file descriptor from the application to the Vulkan implementation. The application must not perform any operations on the file descriptor after a successful import.
Applications can import the same semaphore payload into multiple instances of Vulkan, into the same instance from which it was exported, and multiple times into a given Vulkan instance.
The VkImportSemaphoreFdInfoKHR structure is defined as:
typedef struct VkImportSemaphoreFdInfoKHR {
VkStructureType sType;
const void* pNext;
VkSemaphore semaphore;
VkSemaphoreImportFlags flags;
VkExternalSemaphoreHandleTypeFlagBits handleType;
int fd;
} VkImportSemaphoreFdInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
semaphoreis the semaphore into which the payload will be imported. -
flagsis a bitmask of VkSemaphoreImportFlagBits specifying additional parameters for the semaphore payload import operation. -
handleTypespecifies the type offd. -
fdis the external handle to import.
The handle types supported by handleType are:
| Handle Type | Transference | Permanence Supported |
|---|---|---|
|
Reference |
Temporary,Permanent |
|
Copy |
Temporary |
Additional parameters of a semaphore import operation are specified by
VkImportSemaphoreWin32HandleInfoKHR::flags
or
VkImportSemaphoreFdInfoKHR::flags
.
Bits which can be set include:
typedef enum VkSemaphoreImportFlagBits {
VK_SEMAPHORE_IMPORT_TEMPORARY_BIT = 0x00000001,
VK_SEMAPHORE_IMPORT_TEMPORARY_BIT_KHR = VK_SEMAPHORE_IMPORT_TEMPORARY_BIT,
} VkSemaphoreImportFlagBits;
or the equivalent
typedef VkSemaphoreImportFlagBits VkSemaphoreImportFlagBitsKHR;
These bits have the following meanings:
-
VK_SEMAPHORE_IMPORT_TEMPORARY_BITspecifies that the semaphore payload will be imported only temporarily, as described in Importing Semaphore Payloads, regardless of the permanence ofhandleType.
typedef VkFlags VkSemaphoreImportFlags;
or the equivalent
typedef VkSemaphoreImportFlags VkSemaphoreImportFlagsKHR;
VkSemaphoreImportFlags is a bitmask type for setting a mask of zero or
more VkSemaphoreImportFlagBits.
6.5. Events
Events are a synchronization primitive that can be used to insert a fine-grained dependency between commands submitted to the same queue, or between the host and a queue. Events must not be used to insert a dependency between commands submitted to different queues. Events have two states - signaled and unsignaled. An application can signal an event, or unsignal it, on either the host or the device. A device can wait for an event to become signaled before executing further operations. No command exists to wait for an event to become signaled on the host, but the current state of an event can be queried.
Events are represented by VkEvent handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkEvent)
To create an event, call:
VkResult vkCreateEvent(
VkDevice device,
const VkEventCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkEvent* pEvent);
-
deviceis the logical device that creates the event. -
pCreateInfois a pointer to an instance of theVkEventCreateInfostructure which contains information about how the event is to be created. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pEventpoints to a handle in which the resulting event object is returned.
When created, the event object is in the unsignaled state.
The VkEventCreateInfo structure is defined as:
typedef struct VkEventCreateInfo {
VkStructureType sType;
const void* pNext;
VkEventCreateFlags flags;
} VkEventCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use.
typedef VkFlags VkEventCreateFlags;
VkEventCreateFlags is a bitmask type for setting a mask, but is
currently reserved for future use.
To destroy an event, call:
void vkDestroyEvent(
VkDevice device,
VkEvent event,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the event. -
eventis the handle of the event to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
To query the state of an event from the host, call:
VkResult vkGetEventStatus(
VkDevice device,
VkEvent event);
-
deviceis the logical device that owns the event. -
eventis the handle of the event to query.
Upon success, vkGetEventStatus returns the state of the event object
with the following return codes:
| Status | Meaning |
|---|---|
|
The event specified by |
|
The event specified by |
If a vkCmdSetEvent or vkCmdResetEvent command is in a command
buffer that is in the pending state, then the
value returned by this command may immediately be out of date.
The state of an event can be updated by the host.
The state of the event is immediately changed, and subsequent calls to
vkGetEventStatus will return the new state.
If an event is already in the requested state, then updating it to the same
state has no effect.
To set the state of an event to signaled from the host, call:
VkResult vkSetEvent(
VkDevice device,
VkEvent event);
-
deviceis the logical device that owns the event. -
eventis the event to set.
When vkSetEvent is executed on the host, it defines an event signal operation which sets the event to the signaled state.
If event is already in the signaled state when vkSetEvent is
executed, then vkSetEvent has no effect, and no event signal operation
occurs.
To set the state of an event to unsignaled from the host, call:
VkResult vkResetEvent(
VkDevice device,
VkEvent event);
-
deviceis the logical device that owns the event. -
eventis the event to reset.
When vkResetEvent is executed on the host, it defines an event unsignal operation which resets the event to the unsignaled state.
If event is already in the unsignaled state when vkResetEvent is
executed, then vkResetEvent has no effect, and no event unsignal
operation occurs.
The state of an event can also be updated on the device by commands inserted in command buffers.
To set the state of an event to signaled from a device, call:
void vkCmdSetEvent(
VkCommandBuffer commandBuffer,
VkEvent event,
VkPipelineStageFlags stageMask);
-
commandBufferis the command buffer into which the command is recorded. -
eventis the event that will be signaled. -
stageMaskspecifies the source stage mask used to determine when theeventis signaled.
When vkCmdSetEvent is submitted to a queue, it defines an execution dependency on commands that were submitted before it, and defines an event signal operation which sets the event to the signaled state.
The first synchronization scope
includes all commands that occur earlier in
submission order.
The synchronization scope is limited to operations on the pipeline stages
determined by the source stage
mask specified by stageMask.
The second synchronization scope includes only the event signal operation.
If event is already in the signaled state when vkCmdSetEvent is
executed on the device, then vkCmdSetEvent has no effect, no event
signal operation occurs, and no execution dependency is generated.
To set the state of an event to unsignaled from a device, call:
void vkCmdResetEvent(
VkCommandBuffer commandBuffer,
VkEvent event,
VkPipelineStageFlags stageMask);
-
commandBufferis the command buffer into which the command is recorded. -
eventis the event that will be unsignaled. -
stageMaskis a bitmask of VkPipelineStageFlagBits specifying the source stage mask used to determine when theeventis unsignaled.
When vkCmdResetEvent is submitted to a queue, it defines an execution dependency on commands that were submitted before it, and defines an event unsignal operation which resets the event to the unsignaled state.
The first synchronization scope
includes all commands that occur earlier in
submission order.
The synchronization scope is limited to operations on the pipeline stages
determined by the source stage
mask specified by stageMask.
The second synchronization scope includes only the event unsignal operation.
If event is already in the unsignaled state when vkCmdResetEvent
is executed on the device, then vkCmdResetEvent has no effect, no
event unsignal operation occurs, and no execution dependency is generated.
To wait for one or more events to enter the signaled state on a device, call:
void vkCmdWaitEvents(
VkCommandBuffer commandBuffer,
uint32_t eventCount,
const VkEvent* pEvents,
VkPipelineStageFlags srcStageMask,
VkPipelineStageFlags dstStageMask,
uint32_t memoryBarrierCount,
const VkMemoryBarrier* pMemoryBarriers,
uint32_t bufferMemoryBarrierCount,
const VkBufferMemoryBarrier* pBufferMemoryBarriers,
uint32_t imageMemoryBarrierCount,
const VkImageMemoryBarrier* pImageMemoryBarriers);
-
commandBufferis the command buffer into which the command is recorded. -
eventCountis the length of thepEventsarray. -
pEventsis an array of event object handles to wait on. -
srcStageMaskis a bitmask of VkPipelineStageFlagBits specifying the source stage mask. -
dstStageMaskis a bitmask of VkPipelineStageFlagBits specifying the destination stage mask. -
memoryBarrierCountis the length of thepMemoryBarriersarray. -
pMemoryBarriersis a pointer to an array of VkMemoryBarrier structures. -
bufferMemoryBarrierCountis the length of thepBufferMemoryBarriersarray. -
pBufferMemoryBarriersis a pointer to an array of VkBufferMemoryBarrier structures. -
imageMemoryBarrierCountis the length of thepImageMemoryBarriersarray. -
pImageMemoryBarriersis a pointer to an array of VkImageMemoryBarrier structures.
When vkCmdWaitEvents is submitted to a queue, it defines a memory
dependency between prior event signal operations on the same queue or the
host, and subsequent commands.
vkCmdWaitEvents must not be used to wait on event signal operations
occuring on other queues.
The first synchronization scope only includes event signal operations that
operate on members of pEvents, and the operations that happened-before
the event signal operations.
Event signal operations performed by vkCmdSetEvent that occur earlier
in submission order are included in the
first synchronization scope, if the logically latest pipeline stage in their stageMask parameter is
logically earlier than or equal
to the logically latest pipeline
stage in srcStageMask.
Event signal operations performed by vkSetEvent are only included in
the first synchronization scope if VK_PIPELINE_STAGE_HOST_BIT is
included in srcStageMask.
The second synchronization scope
includes all commands that occur later in
submission order.
The second synchronization scope is limited to operations on the pipeline
stages determined by the destination stage mask specified by dstStageMask.
The first access scope is
limited to access in the pipeline stages determined by the
source stage mask specified by
srcStageMask.
Within that, the first access scope only includes the first access scopes
defined by elements of the pMemoryBarriers,
pBufferMemoryBarriers and pImageMemoryBarriers arrays, which
each define a set of memory barriers.
If no memory barriers are specified, then the first access scope includes no
accesses.
The second access scope is
limited to access in the pipeline stages determined by the
destination stage mask specified
by dstStageMask.
Within that, the second access scope only includes the second access scopes
defined by elements of the pMemoryBarriers,
pBufferMemoryBarriers and pImageMemoryBarriers arrays, which
each define a set of memory barriers.
If no memory barriers are specified, then the second access scope includes
no accesses.
|
Note
vkCmdWaitEvents is used with vkCmdSetEvent to define a memory dependency between two sets of action commands, roughly in the same way as pipeline barriers, but split into two commands such that work between the two may execute unhindered. |
|
Note
Applications should be careful to avoid race conditions when using events. There is no direct ordering guarantee between a vkCmdResetEvent command and a vkCmdWaitEvents command submitted after it, so some other execution dependency must be included between these commands (e.g. a semaphore). |
6.6. Pipeline Barriers
vkCmdPipelineBarrier is a synchronization command that inserts a dependency between commands submitted to the same queue, or between commands in the same subpass.
To record a pipeline barrier, call:
void vkCmdPipelineBarrier(
VkCommandBuffer commandBuffer,
VkPipelineStageFlags srcStageMask,
VkPipelineStageFlags dstStageMask,
VkDependencyFlags dependencyFlags,
uint32_t memoryBarrierCount,
const VkMemoryBarrier* pMemoryBarriers,
uint32_t bufferMemoryBarrierCount,
const VkBufferMemoryBarrier* pBufferMemoryBarriers,
uint32_t imageMemoryBarrierCount,
const VkImageMemoryBarrier* pImageMemoryBarriers);
-
commandBufferis the command buffer into which the command is recorded. -
srcStageMaskis a bitmask of VkPipelineStageFlagBits specifying the source stage mask. -
dstStageMaskis a bitmask of VkPipelineStageFlagBits specifying the destination stage mask. -
dependencyFlagsis a bitmask of VkDependencyFlagBits specifying how execution and memory dependencies are formed. -
memoryBarrierCountis the length of thepMemoryBarriersarray. -
pMemoryBarriersis a pointer to an array of VkMemoryBarrier structures. -
bufferMemoryBarrierCountis the length of thepBufferMemoryBarriersarray. -
pBufferMemoryBarriersis a pointer to an array of VkBufferMemoryBarrier structures. -
imageMemoryBarrierCountis the length of thepImageMemoryBarriersarray. -
pImageMemoryBarriersis a pointer to an array of VkImageMemoryBarrier structures.
When vkCmdPipelineBarrier is submitted to a queue, it defines a memory dependency between commands that were submitted before it, and those submitted after it.
If vkCmdPipelineBarrier was recorded outside a render pass instance,
the first synchronization scope
includes all commands that occur earlier in
submission order.
If vkCmdPipelineBarrier was recorded inside a render pass instance,
the first synchronization scope includes only commands that occur earlier in
submission order within the same
subpass.
In either case, the first synchronization scope is limited to operations on
the pipeline stages determined by the
source stage mask specified by
srcStageMask.
If vkCmdPipelineBarrier was recorded outside a render pass instance,
the second synchronization scope
includes all commands that occur later in
submission order.
If vkCmdPipelineBarrier was recorded inside a render pass instance,
the second synchronization scope includes only commands that occur later in
submission order within the same
subpass.
In either case, the second synchronization scope is limited to operations on
the pipeline stages determined by the
destination stage mask specified
by dstStageMask.
The first access scope is
limited to access in the pipeline stages determined by the
source stage mask specified by
srcStageMask.
Within that, the first access scope only includes the first access scopes
defined by elements of the pMemoryBarriers,
pBufferMemoryBarriers and pImageMemoryBarriers arrays, which
each define a set of memory barriers.
If no memory barriers are specified, then the first access scope includes no
accesses.
The second access scope is
limited to access in the pipeline stages determined by the
destination stage mask specified
by dstStageMask.
Within that, the second access scope only includes the second access scopes
defined by elements of the pMemoryBarriers,
pBufferMemoryBarriers and pImageMemoryBarriers arrays, which
each define a set of memory barriers.
If no memory barriers are specified, then the second access scope includes
no accesses.
If dependencyFlags includes VK_DEPENDENCY_BY_REGION_BIT, then
any dependency between framebuffer-space pipeline stages is
framebuffer-local - otherwise it is
framebuffer-global.
Bits which can be set in vkCmdPipelineBarrier::dependencyFlags,
specifying how execution and memory dependencies are formed, are:
typedef enum VkDependencyFlagBits {
VK_DEPENDENCY_BY_REGION_BIT = 0x00000001,
VK_DEPENDENCY_DEVICE_GROUP_BIT = 0x00000004,
VK_DEPENDENCY_VIEW_LOCAL_BIT = 0x00000002,
VK_DEPENDENCY_VIEW_LOCAL_BIT_KHR = VK_DEPENDENCY_VIEW_LOCAL_BIT,
VK_DEPENDENCY_DEVICE_GROUP_BIT_KHR = VK_DEPENDENCY_DEVICE_GROUP_BIT,
} VkDependencyFlagBits;
-
VK_DEPENDENCY_BY_REGION_BITspecifies that dependencies will be framebuffer-local. -
VK_DEPENDENCY_VIEW_LOCAL_BITspecifies that a subpass has more than one view. -
VK_DEPENDENCY_DEVICE_GROUP_BITspecifies that dependencies are non-device-local dependency.
typedef VkFlags VkDependencyFlags;
VkDependencyFlags is a bitmask type for setting a mask of zero or more
VkDependencyFlagBits.
6.6.1. Subpass Self-dependency
If vkCmdPipelineBarrier is called inside a render pass instance, the
following restrictions apply.
For a given subpass to allow a pipeline barrier, the render pass must
declare a self-dependency from that subpass to itself.
That is, there must exist a VkSubpassDependency in the subpass
dependency list for the render pass with srcSubpass and
dstSubpass equal to that subpass index.
More than one self-dependency can be declared for each subpass.
Self-dependencies must only include pipeline stage bits that are graphics
stages.
Self-dependencies must not have any earlier pipeline stages depend on any
later pipeline stages (according to the order of
graphics pipeline stages), unless
all of the stages are
framebuffer-space stages.
If the source and destination stage masks both include framebuffer-space
stages, then dependencyFlags must include
VK_DEPENDENCY_BY_REGION_BIT.
If the subpass has more than one view, then dependencyFlags must
include VK_DEPENDENCY_VIEW_LOCAL_BIT.
A vkCmdPipelineBarrier command inside a render pass instance must be
a subset of one of the self-dependencies of the subpass it is used in,
meaning that the stage masks and access masks must each include only a
subset of the bits of the corresponding mask in that self-dependency.
If the self-dependency has VK_DEPENDENCY_BY_REGION_BIT
or VK_DEPENDENCY_VIEW_LOCAL_BIT
set, then so must the pipeline barrier.
Pipeline barriers within a render pass instance can only be types
VkMemoryBarrier or VkImageMemoryBarrier.
If a VkImageMemoryBarrier is used, the image and image subresource
range specified in the barrier must be a subset of one of the image views
used by the framebuffer in the current subpass.
Additionally, oldLayout must be equal to newLayout, and both
the srcQueueFamilyIndex and dstQueueFamilyIndex must be
VK_QUEUE_FAMILY_IGNORED.
6.7. Memory Barriers
Memory barriers are used to explicitly control access to buffer and image subresource ranges. Memory barriers are used to transfer ownership between queue families, change image layouts, and define availability and visibility operations. They explicitly define the access types and buffer and image subresource ranges that are included in the access scopes of a memory dependency that is created by a synchronization command that includes them.
6.7.1. Global Memory Barriers
Global memory barriers apply to memory accesses involving all memory objects that exist at the time of its execution.
The VkMemoryBarrier structure is defined as:
typedef struct VkMemoryBarrier {
VkStructureType sType;
const void* pNext;
VkAccessFlags srcAccessMask;
VkAccessFlags dstAccessMask;
} VkMemoryBarrier;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
srcAccessMaskis a bitmask of VkAccessFlagBits specifying a source access mask. -
dstAccessMaskis a bitmask of VkAccessFlagBits specifying a destination access mask.
The first access scope is
limited to access types in the source access
mask specified by srcAccessMask.
The second access scope is
limited to access types in the destination
access mask specified by dstAccessMask.
6.7.2. Buffer Memory Barriers
Buffer memory barriers only apply to memory accesses involving a specific buffer range. That is, a memory dependency formed from an buffer memory barrier is scoped to access via the specified buffer range. Buffer memory barriers can also be used to define a queue family ownership transfer for the specified buffer range.
The VkBufferMemoryBarrier structure is defined as:
typedef struct VkBufferMemoryBarrier {
VkStructureType sType;
const void* pNext;
VkAccessFlags srcAccessMask;
VkAccessFlags dstAccessMask;
uint32_t srcQueueFamilyIndex;
uint32_t dstQueueFamilyIndex;
VkBuffer buffer;
VkDeviceSize offset;
VkDeviceSize size;
} VkBufferMemoryBarrier;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
srcAccessMaskis a bitmask of VkAccessFlagBits specifying a source access mask. -
dstAccessMaskis a bitmask of VkAccessFlagBits specifying a destination access mask. -
srcQueueFamilyIndexis the source queue family for a queue family ownership transfer. -
dstQueueFamilyIndexis the destination queue family for a queue family ownership transfer. -
bufferis a handle to the buffer whose backing memory is affected by the barrier. -
offsetis an offset in bytes into the backing memory forbuffer; this is relative to the base offset as bound to the buffer (see vkBindBufferMemory). -
sizeis a size in bytes of the affected area of backing memory forbuffer, orVK_WHOLE_SIZEto use the range fromoffsetto the end of the buffer.
The first access scope is
limited to access to memory through the specified buffer range, via access
types in the source access mask specified
by srcAccessMask.
If srcAccessMask includes VK_ACCESS_HOST_WRITE_BIT, memory
writes performed by that access type are also made visible, as that access
type is not performed through a resource.
The second access scope is
limited to access to memory through the specified buffer range, via access
types in the destination access mask.
specified by dstAccessMask.
If dstAccessMask includes VK_ACCESS_HOST_WRITE_BIT or
VK_ACCESS_HOST_READ_BIT, available memory writes are also made visible
to accesses of those types, as those access types are not performed through
a resource.
If srcQueueFamilyIndex is not equal to dstQueueFamilyIndex, and
srcQueueFamilyIndex is equal to the current queue family, then the
memory barrier defines a queue
family release operation for the specified buffer range, and the second
access scope includes no access, as if dstAccessMask was 0.
If dstQueueFamilyIndex is not equal to srcQueueFamilyIndex, and
dstQueueFamilyIndex is equal to the current queue family, then the
memory barrier defines a queue
family acquire operation for the specified buffer range, and the first
access scope includes no access, as if srcAccessMask was 0.
6.7.3. Image Memory Barriers
Image memory barriers only apply to memory accesses involving a specific image subresource range. That is, a memory dependency formed from an image memory barrier is scoped to access via the specified image subresource range. Image memory barriers can also be used to define image layout transitions or a queue family ownership transfer for the specified image subresource range.
The VkImageMemoryBarrier structure is defined as:
typedef struct VkImageMemoryBarrier {
VkStructureType sType;
const void* pNext;
VkAccessFlags srcAccessMask;
VkAccessFlags dstAccessMask;
VkImageLayout oldLayout;
VkImageLayout newLayout;
uint32_t srcQueueFamilyIndex;
uint32_t dstQueueFamilyIndex;
VkImage image;
VkImageSubresourceRange subresourceRange;
} VkImageMemoryBarrier;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
srcAccessMaskis a bitmask of VkAccessFlagBits specifying a source access mask. -
dstAccessMaskis a bitmask of VkAccessFlagBits specifying a destination access mask. -
oldLayoutis the old layout in an image layout transition. -
newLayoutis the new layout in an image layout transition. -
srcQueueFamilyIndexis the source queue family for a queue family ownership transfer. -
dstQueueFamilyIndexis the destination queue family for a queue family ownership transfer. -
imageis a handle to the image affected by this barrier. -
subresourceRangedescribes the image subresource range withinimagethat is affected by this barrier.
The first access scope is
limited to access to memory through the specified image subresource range,
via access types in the source access mask
specified by srcAccessMask.
If srcAccessMask includes VK_ACCESS_HOST_WRITE_BIT, memory
writes performed by that access type are also made visible, as that access
type is not performed through a resource.
The second access scope is
limited to access to memory through the specified image subresource range,
via access types in the destination access
mask specified by dstAccessMask.
If dstAccessMask includes VK_ACCESS_HOST_WRITE_BIT or
VK_ACCESS_HOST_READ_BIT, available memory writes are also made visible
to accesses of those types, as those access types are not performed through
a resource.
If srcQueueFamilyIndex is not equal to dstQueueFamilyIndex, and
srcQueueFamilyIndex is equal to the current queue family, then the
memory barrier defines a queue
family release operation for the specified image subresource range, and
the second access scope includes no access, as if dstAccessMask was
0.
If dstQueueFamilyIndex is not equal to srcQueueFamilyIndex, and
dstQueueFamilyIndex is equal to the current queue family, then the
memory barrier defines a queue
family acquire operation for the specified image subresource range, and
the first access scope includes no access, as if srcAccessMask was
0.
If oldLayout is not equal to newLayout, then the memory barrier
defines an image layout
transition for the specified image subresource range.
Layout transitions that are performed via image memory barriers execute in their entirety in submission order, relative to other image layout transitions submitted to the same queue, including those performed by render passes. In effect there is an implicit execution dependency from each such layout transition to all layout transitions previously submitted to the same queue.
The image layout of each image subresource of a depth/stencil image created
with VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT is
dependent on the last sample locations used to render to the image
subresource as a depth/stencil attachment, thus when the image member
of an VkImageMemoryBarrier is an image created with this flag the
application can chain a VkSampleLocationsInfoEXT structure to the
pNext chain of VkImageMemoryBarrier to specify the sample
locations to use during the image layout transition.
If the VkSampleLocationsInfoEXT structure in the pNext chain of
VkImageMemoryBarrier does not match the sample location state last
used to render to the image subresource range specified by
subresourceRange or if no VkSampleLocationsInfoEXT structure is
in the pNext chain of VkImageMemoryBarrier then the contents of
the given image subresource range becomes undefined as if oldLayout
would equal VK_IMAGE_LAYOUT_UNDEFINED.
If image has a multi-planar format and the image is disjoint, then
including VK_IMAGE_ASPECT_COLOR_BIT in the aspectMask member of
subresourceRange is equivalent to including
VK_IMAGE_ASPECT_PLANE_0_BIT, VK_IMAGE_ASPECT_PLANE_1_BIT, and
(for three-plane formats only) VK_IMAGE_ASPECT_PLANE_2_BIT.
6.7.4. Queue Family Ownership Transfer
Resources created with a VkSharingMode of
VK_SHARING_MODE_EXCLUSIVE must have their ownership explicitly
transferred from one queue family to another in order to access their
content in a well-defined manner on a queue in a different queue family.
Resources shared with external APIs or instances using external memory must
also explicitly manage ownership transfers between local and external queues
(or equivalent constructs in external APIs) regardless of the
VkSharingMode specified when creating them.
The special queue family index VK_QUEUE_FAMILY_EXTERNAL represents any
queue external to the resource’s current Vulkan instance, as long as the
queue uses the same underlying physical device
or device group
and uses the same driver version as the resource’s VkDevice, as
indicated by VkPhysicalDeviceIDProperties::deviceUUID and
VkPhysicalDeviceIDProperties::driverUUID.
The special queue family index VK_QUEUE_FAMILY_FOREIGN_EXT represents
any queue external to the resource’s current Vulkan instance, regardless of
the queue’s underlying physical device or driver version.
This includes, for example, queues for fixed-function image processing
devices, media codec devices, and display devices, as well as all queues
that use the same underlying physical device
(or device group)
and driver version as the resource’s VkDevice.
If memory dependencies are correctly expressed between uses of such a
resource between two queues in different families, but no ownership transfer
is defined, the contents of that resource are undefined for any read
accesses performed by the second queue family.
|
Note
If an application does not need the contents of a resource to remain valid when transferring from one queue family to another, then the ownership transfer should be skipped. |
|
Note
Applications should expect transfers to/from
|
A queue family ownership transfer consists of two distinct parts:
-
Release exclusive ownership from the source queue family
-
Acquire exclusive ownership for the destination queue family
An application must ensure that these operations occur in the correct order by defining an execution dependency between them, e.g. using a semaphore.
A release operation is used to
release exclusive ownership of a range of a buffer or image subresource
range.
A release operation is defined by executing a
buffer memory barrier (for a
buffer range) or an image memory
barrier (for an image subresource range), on a queue from the source queue
family.
The srcQueueFamilyIndex parameter of the barrier must be set to the
source queue family index, and the dstQueueFamilyIndex parameter to
the destination queue family index.
dstStageMask is ignored for such a barrier, such that no visibility
operation is executed - the value of this mask does not affect the validity
of the barrier.
The release operation happens-after the availability operation.
An acquire operation is used
to acquire exclusive ownership of a range of a buffer or image subresource
range.
An acquire operation is defined by executing a
buffer memory barrier (for a
buffer range) or an image memory
barrier (for an image subresource range), on a queue from the destination
queue family.
The srcQueueFamilyIndex parameter of the barrier must be set to the
source queue family index, and the dstQueueFamilyIndex parameter to
the destination queue family index.
srcStageMask is ignored for such a barrier, such that no availability
operation is executed - the value of this mask does not affect the validity
of the barrier.
The acquire operation happens-before the visibility operation.
|
Note
Whilst it is not invalid to provide destination or source access masks for memory barriers used for release or acquire operations, respectively, they have no practical effect. Access after a release operation has undefined results, and so visibility for those accesses has no practical effect. Similarly, write access before an acquire operation will produce undefined results for future access, so availability of those writes has no practical use. In an earlier version of the specification, these were required to match on both sides - but this was subsequently relaxed. These masks should be set to 0. |
If the transfer is via an image memory barrier, and an
image layout transition is
desired, then the values of oldLayout and newLayout in the
release memory barrier must be equal to values of oldLayout and
newLayout in the acquire memory barrier.
Although the image layout transition is submitted twice, it will only be
executed once.
A layout transition specified in this way happens-after the release
operation and happens-before the acquire operation.
If the values of srcQueueFamilyIndex and dstQueueFamilyIndex are
equal, no ownership transfer is performed, and the barrier operates as if
they were both set to VK_QUEUE_FAMILY_IGNORED.
Queue family ownership transfers may perform read and write accesses on all memory bound to the image subresource or buffer range, so applications must ensure that all memory writes have been made available before a queue family ownership transfer is executed. Available memory is automatically made visible to queue family release and acquire operations, and writes performed by those operations are automatically made available.
Once a queue family has acquired ownership of a buffer range or image
subresource range of an VK_SHARING_MODE_EXCLUSIVE resource, its
contents are undefined to other queue families unless ownership is
transferred.
The contents of any portion of another resource which aliases memory that is
bound to the transferred buffer or image subresource range are undefined
after a release or acquire operation.
6.8. Wait Idle Operations
To wait on the host for the completion of outstanding queue operations for a given queue, call:
VkResult vkQueueWaitIdle(
VkQueue queue);
-
queueis the queue on which to wait.
vkQueueWaitIdle is equivalent to submitting a fence to a queue and
waiting with an infinite timeout for that fence to signal.
To wait on the host for the completion of outstanding queue operations for all queues on a given logical device, call:
VkResult vkDeviceWaitIdle(
VkDevice device);
-
deviceis the logical device to idle.
vkDeviceWaitIdle is equivalent to calling vkQueueWaitIdle for
all queues owned by device.
6.9. Host Write Ordering Guarantees
When batches of command buffers are submitted to a queue via vkQueueSubmit, it defines a memory dependency with prior host operations, and execution of command buffers submitted to the queue.
The first synchronization scope is defined by the host execution model, but includes execution of vkQueueSubmit on the host and anything that happened-before it.
The second synchronization scope includes all commands submitted in the same queue submission, and all commands that occur later in submission order.
The first access scope includes all host writes to mappable device memory that are either coherent, or have been flushed with vkFlushMappedMemoryRanges.
The second access scope includes all memory access performed by the device.
6.10. Synchronization and Multiple Physical Devices
If a logical device includes more than one physical device, then fences, semaphores, and events all still have a single instance of the signaled state.
A fence becomes signaled when all physical devices complete the necessary queue operations.
Semaphore wait and signal operations all include a device index that is the sole physical device that performs the operation. These indices are provided in the VkDeviceGroupSubmitInfo and VkDeviceGroupBindSparseInfo structures. Semaphores are not exclusively owned by any physical device. For example, a semaphore can be signaled by one physical device and then waited on by a different physical device.
An event can only be waited on by the same physical device that signaled it (or the host).
7. Render Pass
A render pass represents a collection of attachments, subpasses, and dependencies between the subpasses, and describes how the attachments are used over the course of the subpasses. The use of a render pass in a command buffer is a render pass instance.
Render passes are represented by VkRenderPass handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkRenderPass)
An attachment description describes the properties of an attachment including its format, sample count, and how its contents are treated at the beginning and end of each render pass instance.
A subpass represents a phase of rendering that reads and writes a subset of the attachments in a render pass. Rendering commands are recorded into a particular subpass of a render pass instance.
A subpass description describes the subset of attachments that is involved in the execution of a subpass. Each subpass can read from some attachments as input attachments, write to some as color attachments or depth/stencil attachments, and perform multisample resolve operations to resolve attachments. A subpass description can also include a set of preserve attachments, which are attachments that are not read or written by the subpass but whose contents must be preserved throughout the subpass.
A subpass uses an attachment if the attachment is a color, depth/stencil,
resolve, or input attachment for that subpass (as determined by the
pColorAttachments, pDepthStencilAttachment,
pResolveAttachments, and pInputAttachments members of
VkSubpassDescription, respectively).
A subpass does not use an attachment if that attachment is preserved by the
subpass.
The first use of an attachment is in the lowest numbered subpass that uses
that attachment.
Similarly, the last use of an attachment is in the highest numbered
subpass that uses that attachment.
The subpasses in a render pass all render to the same dimensions, and fragments for pixel (x,y,layer) in one subpass can only read attachment contents written by previous subpasses at that same (x,y,layer) location.
|
Note
By describing a complete set of subpasses in advance, render passes provide the implementation an opportunity to optimize the storage and transfer of attachment data between subpasses. In practice, this means that subpasses with a simple framebuffer-space dependency may be merged into a single tiled rendering pass, keeping the attachment data on-chip for the duration of a render pass instance. However, it is also quite common for a render pass to only contain a single subpass. |
Subpass dependencies describe execution and memory dependencies between subpasses.
A subpass dependency chain is a sequence of subpass dependencies in a render pass, where the source subpass of each subpass dependency (after the first) equals the destination subpass of the previous dependency.
Execution of subpasses may overlap or execute out of order with regards to other subpasses, unless otherwise enforced by an execution dependency. Each subpass only respects submission order for commands recorded in the same subpass, and the vkCmdBeginRenderPass and vkCmdEndRenderPass commands that delimit the render pass - commands within other subpasses are not included. This affects most other implicit ordering guarantees.
A render pass describes the structure of subpasses and attachments
independent of any specific image views for the attachments.
The specific image views that will be used for the attachments, and their
dimensions, are specified in VkFramebuffer objects.
Framebuffers are created with respect to a specific render pass that the
framebuffer is compatible with (see Render Pass
Compatibility).
Collectively, a render pass and a framebuffer define the complete render
target state for one or more subpasses as well as the algorithmic
dependencies between the subpasses.
The various pipeline stages of the drawing commands for a given subpass may execute concurrently and/or out of order, both within and across drawing commands, whilst still respecting pipeline order. However for a given (x,y,layer,sample) sample location, certain per-sample operations are performed in rasterization order.
7.1. Render Pass Creation
To create a render pass, call:
VkResult vkCreateRenderPass(
VkDevice device,
const VkRenderPassCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkRenderPass* pRenderPass);
-
deviceis the logical device that creates the render pass. -
pCreateInfois a pointer to an instance of the VkRenderPassCreateInfo structure that describes the parameters of the render pass. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pRenderPasspoints to aVkRenderPasshandle in which the resulting render pass object is returned.
The VkRenderPassCreateInfo structure is defined as:
typedef struct VkRenderPassCreateInfo {
VkStructureType sType;
const void* pNext;
VkRenderPassCreateFlags flags;
uint32_t attachmentCount;
const VkAttachmentDescription* pAttachments;
uint32_t subpassCount;
const VkSubpassDescription* pSubpasses;
uint32_t dependencyCount;
const VkSubpassDependency* pDependencies;
} VkRenderPassCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
attachmentCountis the number of attachments used by this render pass, or zero indicating no attachments. Attachments are referred to by zero-based indices in the range [0,attachmentCount). -
pAttachmentspoints to an array ofattachmentCountnumber of VkAttachmentDescription structures describing properties of the attachments, orNULLifattachmentCountis zero. -
subpassCountis the number of subpasses to create for this render pass. Subpasses are referred to by zero-based indices in the range [0,subpassCount). A render pass must have at least one subpass. -
pSubpassespoints to an array ofsubpassCountnumber of VkSubpassDescription structures describing properties of the subpasses. -
dependencyCountis the number of dependencies between pairs of subpasses, or zero indicating no dependencies. -
pDependenciespoints to an array ofdependencyCountnumber of VkSubpassDependency structures describing dependencies between pairs of subpasses, orNULLifdependencyCountis zero.
typedef VkFlags VkRenderPassCreateFlags;
VkRenderPassCreateFlags is a bitmask type for setting a mask, but is
currently reserved for future use.
If the VkRenderPassCreateInfo::pNext chain includes a
VkRenderPassMultiviewCreateInfo structure, then that structure
includes an array of view masks, view offsets, and correlation masks for the
render pass.
The VkRenderPassMultiviewCreateInfo structure is defined as:
typedef struct VkRenderPassMultiviewCreateInfo {
VkStructureType sType;
const void* pNext;
uint32_t subpassCount;
const uint32_t* pViewMasks;
uint32_t dependencyCount;
const int32_t* pViewOffsets;
uint32_t correlationMaskCount;
const uint32_t* pCorrelationMasks;
} VkRenderPassMultiviewCreateInfo;
or the equivalent
typedef VkRenderPassMultiviewCreateInfo VkRenderPassMultiviewCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
subpassCountis zero or is the number of subpasses in the render pass. -
pViewMaskspoints to an array ofsubpassCountnumber of view masks, where each mask is a bitfield of view indices describing which views rendering is broadcast to in each subpass, when multiview is enabled. IfsubpassCountis zero, each view mask is treated as zero. -
dependencyCountis zero or the number of dependencies in the render pass. -
pViewOffsetspoints to an array ofdependencyCountview offsets, one for each dependency. IfdependencyCountis zero, each dependency’s view offset is treated as zero. Each view offset controls which views in the source subpass the views in the destination subpass depend on. -
correlationMaskCountis zero or a number of correlation masks. -
pCorrelationMasksis an array of view masks indicating sets of views that may be more efficient to render concurrently.
When a subpass uses a non-zero view mask, multiview functionality is
considered to be enabled.
Multiview is all-or-nothing for a render pass - that is, either all
subpasses must have a non-zero view mask (though some subpasses may have
only one view) or all must be zero.
Multiview causes all drawing and clear commands in the subpass to behave as
if they were broadcast to each view, where a view is represented by one
layer of the framebuffer attachments.
All draws and clears are broadcast to each view index whose bit is set in
the view mask.
The view index is provided in the ViewIndex shader input variable, and
color, depth/stencil, and input attachments all read/write the layer of the
framebuffer corresponding to the view index.
If the view mask is zero for all subpasses, multiview is considered to be disabled and all drawing commands execute normally, without this additional broadcasting.
Some implementations may not support multiview in conjunction with geometry shaders or tessellation shaders.
When multiview is enabled, the VK_DEPENDENCY_VIEW_LOCAL_BIT bit in a
dependency can be used to express a view-local dependency, meaning that
each view in the destination subpass depends on a single view in the source
subpass.
Unlike pipeline barriers, a subpass dependency can potentially have a
different view mask in the source subpass and the destination subpass.
If the dependency is view-local, then each view (dstView) in the
destination subpass depends on the view dstView +
pViewOffsets[dependency] in the source subpass.
If there is not such a view in the source subpass, then this dependency does
not affect that view in the destination subpass.
If the dependency is not view-local, then all views in the destination
subpass depend on all views in the source subpass, and the view offset is
ignored.
A non-zero view offset is not allowed in a self-dependency.
The elements of pCorrelationMasks are a set of masks of views
indicating that views in the same mask may exhibit spatial coherency
between the views, making it more efficient to render them concurrently.
Correlation masks must not have a functional effect on the results of the
multiview rendering.
When multiview is enabled, at the beginning of each subpass all non-render pass state is undefined. In particular, each time vkCmdBeginRenderPass or vkCmdNextSubpass is called the graphics pipeline must be bound, any relevant descriptor sets or vertex/index buffers must be bound, and any relevant dynamic state or push constants must be set before they are used.
A multiview subpass can declare that its shaders will write per-view
attributes for all views in a single invocation, by setting the
VK_SUBPASS_DESCRIPTION_PER_VIEW_ATTRIBUTES_BIT_NVX bit in the subpass
description.
The only supported per-view attributes are position and viewport mask, and
per-view position and viewport masks are written to output array variables
decorated with PositionPerViewNV and ViewportMaskPerViewNV,
respectively.
If VK_NV_viewport_array2 is not supported and enabled,
ViewportMaskPerViewNV must not be used.
Values written to elements of PositionPerViewNV and
ViewportMaskPerViewNV must not depend on the ViewIndex.
The shader must also write to an output variable decorated with
Position, and the value written to Position must equal the value
written to PositionPerViewNV[ViewIndex].
Similarly, if ViewportMaskPerViewNV is written to then the shader must
also write to an output variable decorated with ViewportMaskNV, and the
value written to ViewportMaskNV must equal the value written to
ViewportMaskPerViewNV[ViewIndex].
Implementations will either use values taken from Position and
ViewportMaskNV and invoke the shader once for each view, or will use
values taken from PositionPerViewNV and ViewportMaskPerViewNV and
invoke the shader fewer times.
The values written to Position and ViewportMaskNV must not depend
on the values written to PositionPerViewNV and
ViewportMaskPerViewNV, or vice versa (to allow compilers to eliminate
the unused outputs).
All attributes that do not have *PerViewNV counterparts must not depend on
ViewIndex.
Per-view attributes are all-or-nothing for a subpass.
That is, all pipelines compiled against a subpass that includes the
VK_SUBPASS_DESCRIPTION_PER_VIEW_ATTRIBUTES_BIT_NVX bit must write
per-view attributes to the *PerViewNV[] shader outputs, in addition to the
non-per-view (e.g. Position) outputs.
Pipelines compiled against a subpass that does not include this bit must
not include the *PerViewNV[] outputs in their interfaces.
The VkAttachmentDescription structure is defined as:
typedef struct VkAttachmentDescription {
VkAttachmentDescriptionFlags flags;
VkFormat format;
VkSampleCountFlagBits samples;
VkAttachmentLoadOp loadOp;
VkAttachmentStoreOp storeOp;
VkAttachmentLoadOp stencilLoadOp;
VkAttachmentStoreOp stencilStoreOp;
VkImageLayout initialLayout;
VkImageLayout finalLayout;
} VkAttachmentDescription;
-
flagsis a bitmask of VkAttachmentDescriptionFlagBits specifying additional properties of the attachment. -
formatis a VkFormat value specifying the format of the image view that will be used for the attachment. -
samplesis the number of samples of the image as defined in VkSampleCountFlagBits. -
loadOpis a VkAttachmentLoadOp value specifying how the contents of color and depth components of the attachment are treated at the beginning of the subpass where it is first used. -
storeOpis a VkAttachmentStoreOp value specifying how the contents of color and depth components of the attachment are treated at the end of the subpass where it is last used. -
stencilLoadOpis a VkAttachmentLoadOp value specifying how the contents of stencil components of the attachment are treated at the beginning of the subpass where it is first used. -
stencilStoreOpis a VkAttachmentStoreOp value specifying how the contents of stencil components of the attachment are treated at the end of the last subpass where it is used. -
initialLayoutis the layout the attachment image subresource will be in when a render pass instance begins. -
finalLayoutis the layout the attachment image subresource will be transitioned to when a render pass instance ends. During a render pass instance, an attachment can use a different layout in each subpass, if desired.
If the attachment uses a color format, then loadOp and storeOp
are used, and stencilLoadOp and stencilStoreOp are ignored.
If the format has depth and/or stencil components, loadOp and
storeOp apply only to the depth data, while stencilLoadOp and
stencilStoreOp define how the stencil data is handled.
loadOp and stencilLoadOp define the load operations that
execute as part of the first subpass that uses the attachment.
storeOp and stencilStoreOp define the store operations that
execute as part of the last subpass that uses the attachment.
The load operation for each sample in an attachment happens-before any
recorded command which accesses the sample in the first subpass where the
attachment is used.
Load operations for attachments with a depth/stencil format execute in the
VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT pipeline stage.
Load operations for attachments with a color format execute in the
VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT pipeline stage.
The store operation for each sample in an attachment happens-after any
recorded command which accesses the sample in the last subpass where the
attachment is used.
Store operations for attachments with a depth/stencil format execute in the
VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT pipeline stage.
Store operations for attachments with a color format execute in the
VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT pipeline stage.
If an attachment is not used by any subpass, then loadOp,
storeOp, stencilStoreOp, and stencilLoadOp are ignored,
and the attachment’s memory contents will not be modified by execution of a
render pass instance.
The load and store operations apply on the first and last use of each view in the render pass, respectively. If a view index of an attachment is not included in the view mask in any subpass that uses it, then the load and store operations are ignored, and the attachment’s memory contents will not be modified by execution of a render pass instance.
During a render pass instance, input/color attachments with color formats
that have a component size of 8, 16, or 32 bits must be represented in the
attachment’s format throughout the instance.
Attachments with other floating- or fixed-point color formats, or with depth
components may be represented in a format with a precision higher than the
attachment format, but must be represented with the same range.
When such a component is loaded via the loadOp, it will be converted
into an implementation-dependent format used by the render pass.
Such components must be converted from the render pass format, to the
format of the attachment, before they are resolved or stored at the end of a
render pass instance via storeOp.
Conversions occur as described in Numeric
Representation and Computation and Fixed-Point
Data Conversions.
If flags includes VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT, then
the attachment is treated as if it shares physical memory with another
attachment in the same render pass.
This information limits the ability of the implementation to reorder certain
operations (like layout transitions and the loadOp) such that it is
not improperly reordered against other uses of the same physical memory via
a different attachment.
This is described in more detail below.
To specify which aspects of an input attachment can be read add a
VkRenderPassInputAttachmentAspectCreateInfo structure to the
pNext chain of the VkRenderPassCreateInfo structure:
The VkRenderPassInputAttachmentAspectCreateInfo structure is defined
as:
typedef struct VkRenderPassInputAttachmentAspectCreateInfo {
VkStructureType sType;
const void* pNext;
uint32_t aspectReferenceCount;
const VkInputAttachmentAspectReference* pAspectReferences;
} VkRenderPassInputAttachmentAspectCreateInfo;
or the equivalent
typedef VkRenderPassInputAttachmentAspectCreateInfo VkRenderPassInputAttachmentAspectCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
aspectReferenceCountis the number of elements in the pAspectReferences array. -
pAspectReferencespoints to an array ofaspectReferenceCountnumber of VkInputAttachmentAspectReference structures describing which aspect(s) can be accessed for a given input attachment within a given subpass.
The VkInputAttachmentAspectReference structure specifies an aspect
mask for a specific input attachment of a specific subpass in the render
pass.
subpass and inputAttachmentIndex index into the render pass as:
pCreateInfo::pSubpasses[subpass].pInputAttachments[inputAttachmentIndex]
typedef struct VkInputAttachmentAspectReference {
uint32_t subpass;
uint32_t inputAttachmentIndex;
VkImageAspectFlags aspectMask;
} VkInputAttachmentAspectReference;
or the equivalent
typedef VkInputAttachmentAspectReference VkInputAttachmentAspectReferenceKHR;
-
subpassis an index into thepSubpassesarray of the parentVkRenderPassCreateInfostructure. -
inputAttachmentIndexis an index into thepInputAttachmentsof the specified subpass. -
aspectMaskis a mask of which aspect(s) can be accessed within the specified subpass.
|
editing-note
TODO (Jon) - it’s unclear whether the following two paragraphs are intended to apply to VkAttachmentDescription, one of the extension structures described immediately above, or something else. The following description of VkAttachmentDescriptionFlagBits should probably be moved up to near VkAttachmentDescription. |
An application must only access the specified aspect(s).
An application can access any aspect of an input attachment that does not have a specified aspect mask.
Bits which can be set in VkAttachmentDescription::flags
describing additional properties of the attachment are:
typedef enum VkAttachmentDescriptionFlagBits {
VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT = 0x00000001,
} VkAttachmentDescriptionFlagBits;
-
VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BITspecifies that the attachment aliases the same device memory as other attachments.
typedef VkFlags VkAttachmentDescriptionFlags;
VkAttachmentDescriptionFlags is a bitmask type for setting a mask of
zero or more VkAttachmentDescriptionFlagBits.
Possible values of VkAttachmentDescription::loadOp and
stencilLoadOp, specifying how the contents of the attachment are
treated, are:
typedef enum VkAttachmentLoadOp {
VK_ATTACHMENT_LOAD_OP_LOAD = 0,
VK_ATTACHMENT_LOAD_OP_CLEAR = 1,
VK_ATTACHMENT_LOAD_OP_DONT_CARE = 2,
} VkAttachmentLoadOp;
-
VK_ATTACHMENT_LOAD_OP_LOADspecifies that the previous contents of the image within the render area will be preserved. For attachments with a depth/stencil format, this uses the access typeVK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BIT. For attachments with a color format, this uses the access typeVK_ACCESS_COLOR_ATTACHMENT_READ_BIT. -
VK_ATTACHMENT_LOAD_OP_CLEARspecifies that the contents within the render area will be cleared to a uniform value, which is specified when a render pass instance is begun. For attachments with a depth/stencil format, this uses the access typeVK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT. For attachments with a color format, this uses the access typeVK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT. -
VK_ATTACHMENT_LOAD_OP_DONT_CAREspecifies that the previous contents within the area need not be preserved; the contents of the attachment will be undefined inside the render area. For attachments with a depth/stencil format, this uses the access typeVK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT. For attachments with a color format, this uses the access typeVK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT.
Possible values of VkAttachmentDescription::storeOp and
stencilStoreOp, specifying how the contents of the attachment are
treated, are:
typedef enum VkAttachmentStoreOp {
VK_ATTACHMENT_STORE_OP_STORE = 0,
VK_ATTACHMENT_STORE_OP_DONT_CARE = 1,
} VkAttachmentStoreOp;
-
VK_ATTACHMENT_STORE_OP_STOREspecifies the contents generated during the render pass and within the render area are written to memory. For attachments with a depth/stencil format, this uses the access typeVK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT. For attachments with a color format, this uses the access typeVK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT. -
VK_ATTACHMENT_STORE_OP_DONT_CAREspecifies the contents within the render area are not needed after rendering, and may be discarded; the contents of the attachment will be undefined inside the render area. For attachments with a depth/stencil format, this uses the access typeVK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT. For attachments with a color format, this uses the access typeVK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT.
|
editing-note
TODO (Jon) - the following text may need to be moved back to combine with vkCreateRenderPass above for automatic ref page generation. |
If a render pass uses multiple attachments that alias the same device
memory, those attachments must each include the
VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT bit in their attachment
description flags.
Attachments aliasing the same memory occurs in multiple ways:
-
Multiple attachments being assigned the same image view as part of framebuffer creation.
-
Attachments using distinct image views that correspond to the same image subresource of an image.
-
Attachments using views of distinct image subresources which are bound to overlapping memory ranges.
|
Note
Render passes must include subpass dependencies (either directly or via a
subpass dependency chain) between any two subpasses that operate on the same
attachment or aliasing attachments and those subpass dependencies must
include execution and memory dependencies separating uses of the aliases, if
at least one of those subpasses writes to one of the aliases.
These dependencies must not include the |
Multiple attachments that alias the same memory must not be used in a single subpass. A given attachment index must not be used multiple times in a single subpass, with one exception: two subpass attachments can use the same attachment index if at least one use is as an input attachment and neither use is as a resolve or preserve attachment. In other words, the same view can be used simultaneously as an input and color or depth/stencil attachment, but must not be used as multiple color or depth/stencil attachments nor as resolve or preserve attachments. The precise set of valid scenarios is described in more detail below.
If a set of attachments alias each other, then all except the first to be
used in the render pass must use an initialLayout of
VK_IMAGE_LAYOUT_UNDEFINED, since the earlier uses of the other aliases
make their contents undefined.
Once an alias has been used and a different alias has been used after it,
the first alias must not be used in any later subpasses.
However, an application can assign the same image view to multiple aliasing
attachment indices, which allows that image view to be used multiple times
even if other aliases are used in between.
|
Note
Once an attachment needs the |
The VkSubpassDescription structure is defined as:
typedef struct VkSubpassDescription {
VkSubpassDescriptionFlags flags;
VkPipelineBindPoint pipelineBindPoint;
uint32_t inputAttachmentCount;
const VkAttachmentReference* pInputAttachments;
uint32_t colorAttachmentCount;
const VkAttachmentReference* pColorAttachments;
const VkAttachmentReference* pResolveAttachments;
const VkAttachmentReference* pDepthStencilAttachment;
uint32_t preserveAttachmentCount;
const uint32_t* pPreserveAttachments;
} VkSubpassDescription;
-
flagsis a bitmask of VkSubpassDescriptionFlagBits specifying usage of the subpass. -
pipelineBindPointis a VkPipelineBindPoint value specifying whether this is a compute or graphics subpass. Currently, only graphics subpasses are supported. -
inputAttachmentCountis the number of input attachments. -
pInputAttachmentsis an array of VkAttachmentReference structures (defined below) that lists which of the render pass’s attachments can be read in the fragment shader stage during the subpass, and what layout each attachment will be in during the subpass. Each element of the array corresponds to an input attachment unit number in the shader, i.e. if the shader declares an input variablelayout(input_attachment_index=X, set=Y, binding=Z)then it uses the attachment provided inpInputAttachments[X]. Input attachments must also be bound to the pipeline with a descriptor set, with the input attachment descriptor written in the location (set=Y, binding=Z). Fragment shaders can use subpass input variables to access the contents of an input attachment at the fragment’s (x, y, layer) framebuffer coordinates. -
colorAttachmentCountis the number of color attachments. -
pColorAttachmentsis an array ofcolorAttachmentCountVkAttachmentReference structures that lists which of the render pass’s attachments will be used as color attachments in the subpass, and what layout each attachment will be in during the subpass. Each element of the array corresponds to a fragment shader output location, i.e. if the shader declared an output variablelayout(location=X)then it uses the attachment provided inpColorAttachments[X]. -
pResolveAttachmentsisNULLor an array ofcolorAttachmentCountVkAttachmentReference structures that lists which of the render pass’s attachments are resolved to at the end of the subpass, and what layout each attachment will be in during the multisample resolve operation. IfpResolveAttachmentsis notNULL, each of its elements corresponds to a color attachment (the element inpColorAttachmentsat the same index), and a multisample resolve operation is defined for each attachment. At the end of each subpass, multisample resolve operations read the subpass’s color attachments, and resolve the samples for each pixel to the same pixel location in the corresponding resolve attachments, unless the resolve attachment index isVK_ATTACHMENT_UNUSED. If the first use of an attachment in a render pass is as a resolve attachment, then theloadOpis effectively ignored as the resolve is guaranteed to overwrite all pixels in the render area. -
pDepthStencilAttachmentis a pointer to a VkAttachmentReference specifying which attachment will be used for depth/stencil data and the layout it will be in during the subpass. Setting the attachment index toVK_ATTACHMENT_UNUSEDor leaving this pointer asNULLindicates that no depth/stencil attachment will be used in the subpass. -
preserveAttachmentCountis the number of preserved attachments. -
pPreserveAttachmentsis an array ofpreserveAttachmentCountrender pass attachment indices describing the attachments that are not used by a subpass, but whose contents must be preserved throughout the subpass.
The contents of an attachment within the render area become undefined at the start of a subpass S if all of the following conditions are true:
-
The attachment is used as a color, depth/stencil, or resolve attachment in any subpass in the render pass.
-
There is a subpass S1 that uses or preserves the attachment, and a subpass dependency from S1 to S.
-
The attachment is not used or preserved in subpass S.
Once the contents of an attachment become undefined in subpass S, they remain undefined for subpasses in subpass dependency chains starting with subpass S until they are written again. However, they remain valid for subpasses in other subpass dependency chains starting with subpass S1 if those subpasses use or preserve the attachment.
Bits which can be set in VkSubpassDescription::flags,
specifying usage of the subpass, are:
typedef enum VkSubpassDescriptionFlagBits {
VK_SUBPASS_DESCRIPTION_PER_VIEW_ATTRIBUTES_BIT_NVX = 0x00000001,
VK_SUBPASS_DESCRIPTION_PER_VIEW_POSITION_X_ONLY_BIT_NVX = 0x00000002,
} VkSubpassDescriptionFlagBits;
-
VK_SUBPASS_DESCRIPTION_PER_VIEW_ATTRIBUTES_BIT_NVXspecifies that shaders compiled for this subpass write the attributes for all views in a single invocation of each vertex processing stage. All pipelines compiled against a subpass that includes this bit must write per-view attributes to the code:*PerViewNV[] shader outputs, in addition to the non-per-view (e.g.Position) outputs. -
VK_SUBPASS_DESCRIPTION_PER_VIEW_POSITION_X_ONLY_BIT_NVXspecifies that shaders compiled for this subpass use per-view positions which only differ in value in the x component. Per-view viewport mask can also be used.
typedef VkFlags VkSubpassDescriptionFlags;
VkSubpassDescriptionFlags is a bitmask type for setting a mask of zero
or more VkSubpassDescriptionFlagBits.
The VkAttachmentReference structure is defined as:
typedef struct VkAttachmentReference {
uint32_t attachment;
VkImageLayout layout;
} VkAttachmentReference;
-
attachmentis the index of the attachment of the render pass, and corresponds to the index of the corresponding element in thepAttachmentsarray of theVkRenderPassCreateInfostructure. If any color or depth/stencil attachments areVK_ATTACHMENT_UNUSED, then no writes occur for those attachments. -
layoutis a VkImageLayout value specifying the layout the attachment uses during the subpass.
The VkSubpassDependency structure is defined as:
typedef struct VkSubpassDependency {
uint32_t srcSubpass;
uint32_t dstSubpass;
VkPipelineStageFlags srcStageMask;
VkPipelineStageFlags dstStageMask;
VkAccessFlags srcAccessMask;
VkAccessFlags dstAccessMask;
VkDependencyFlags dependencyFlags;
} VkSubpassDependency;
-
srcSubpassis the subpass index of the first subpass in the dependency, orVK_SUBPASS_EXTERNAL. -
dstSubpassis the subpass index of the second subpass in the dependency, orVK_SUBPASS_EXTERNAL. -
srcStageMaskis a bitmask of VkPipelineStageFlagBits specifying the source stage mask. -
dstStageMaskis a bitmask of VkPipelineStageFlagBits specifying the destination stage mask -
srcAccessMaskis a bitmask of VkAccessFlagBits specifying a source access mask. -
dstAccessMaskis a bitmask of VkAccessFlagBits specifying a destination access mask. -
dependencyFlagsis a bitmask of VkDependencyFlagBits.
If srcSubpass is equal to dstSubpass then the
VkSubpassDependency describes a
subpass
self-dependency, and only constrains the pipeline barriers allowed within
a subpass instance.
Otherwise, when a render pass instance which includes a subpass dependency
is submitted to a queue, it defines a memory dependency between the
subpasses identified by srcSubpass and dstSubpass.
If srcSubpass is equal to VK_SUBPASS_EXTERNAL, the first
synchronization scope includes
commands that occur earlier in submission
order than the vkCmdBeginRenderPass used to begin the render pass
instance.
Otherwise, the first set of commands includes all commands submitted as part
of the subpass instance identified by srcSubpass and any load, store
or multisample resolve operations on attachments used in srcSubpass.
In either case, the first synchronization scope is limited to operations on
the pipeline stages determined by the
source stage mask specified by
srcStageMask.
If dstSubpass is equal to VK_SUBPASS_EXTERNAL, the second
synchronization scope includes
commands that occur later in submission
order than the vkCmdEndRenderPass used to end the render pass
instance.
Otherwise, the second set of commands includes all commands submitted as
part of the subpass instance identified by dstSubpass and any load,
store or multisample resolve operations on attachments used in
dstSubpass.
In either case, the second synchronization scope is limited to operations on
the pipeline stages determined by the
destination stage mask specified
by dstStageMask.
The first access scope is
limited to access in the pipeline stages determined by the
source stage mask specified by
srcStageMask.
It is also limited to access types in the source access mask specified by srcAccessMask.
The second access scope is
limited to access in the pipeline stages determined by the
destination stage mask specified
by dstStageMask.
It is also limited to access types in the destination access mask specified by dstAccessMask.
The availability and visibility operations defined by a subpass dependency affect the execution of image layout transitions within the render pass.
|
Note
For non-attachment resources, the memory dependency expressed by subpass
dependency is nearly identical to that of a VkMemoryBarrier (with
matching For attachments however, subpass dependencies work more like an
VkImageMemoryBarrier defined similarly to the VkMemoryBarrier
above, the queue family indices set to
|
When multiview is enabled, the execution of the multiple views of one
subpass may not occur simultaneously or even back-to-back, and rather may
be interleaved with the execution of other subpasses.
The load and store operations apply to attachments on a per-view basis.
For example, an attachment using VK_ATTACHMENT_LOAD_OP_CLEAR will have
each view cleared on first use, but the first use of one view may be
temporally distant from the first use of another view.
|
Note
A good mental model for multiview is to think of a multiview subpass as if it were a collection of individual (per-view) subpasses that are logically grouped together and described as a single multiview subpass in the API. Similarly, a multiview attachment can be thought of like several individual attachments that happen to be layers in a single image. A view-local dependency between two multiview subpasses acts like a set of one-to-one dependencies between corresponding pairs of per-view subpasses. A view-global dependency between two multiview subpasses acts like a set of N × M dependencies between all pairs of per-view subpasses in the source and destination. Thus, it is a more compact representation which also makes clear the commonality and reuse that is present between views in a subpass. This interpretation motivates the answers to questions like “when does the load op apply” - it is on the first use of each view of an attachment, as if each view were a separate attachment. |
|
editing-note
The following two alleged implicit dependencies are practically no-ops, as the operations they describe are already guaranteed by semaphores and submission order (so they’re almost entirely no-ops on their own). The only reason they exist is because it simplifies reasoning about where automatic layout transitions happen. Further rewrites of this chapter could potentially remove the need for these. |
If there is no subpass dependency from VK_SUBPASS_EXTERNAL to the
first subpass that uses an attachment, then an implicit subpass dependency
exists from VK_SUBPASS_EXTERNAL to the first subpass it is used in.
The subpass dependency operates as if defined with the following parameters:
VkSubpassDependency implicitDependency = {
.srcSubpass = VK_SUBPASS_EXTERNAL;
.dstSubpass = firstSubpass; // First subpass attachment is used in
.srcStageMask = VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT;
.dstStageMask = VK_PIPELINE_STAGE_ALL_COMMANDS_BIT;
.srcAccessMask = 0;
.dstAccessMask = VK_ACCESS_INPUT_ATTACHMENT_READ_BIT |
VK_ACCESS_COLOR_ATTACHMENT_READ_BIT |
VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT |
VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BIT |
VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT;
.dependencyFlags = 0;
};
Similarly, if there is no subpass dependency from the last subpass that uses
an attachment to VK_SUBPASS_EXTERNAL, then an implicit subpass
dependency exists from the last subpass it is used in to
VK_SUBPASS_EXTERNAL.
The subpass dependency operates as if defined with the following parameters:
VkSubpassDependency implicitDependency = {
.srcSubpass = lastSubpass; // Last subpass attachment is used in
.dstSubpass = VK_SUBPASS_EXTERNAL;
.srcStageMask = VK_PIPELINE_STAGE_ALL_COMMANDS_BIT;
.dstStageMask = VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT;
.srcAccessMask = VK_ACCESS_INPUT_ATTACHMENT_READ_BIT |
VK_ACCESS_COLOR_ATTACHMENT_READ_BIT |
VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT |
VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BIT |
VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT;
.dstAccessMask = 0;
.dependencyFlags = 0;
};
As subpasses may overlap or execute out of order with regards to other subpasses unless a subpass dependency chain describes otherwise, the layout transitions required between subpasses cannot be known to an application. Instead, an application provides the layout that each attachment must be in at the start and end of a render pass, and the layout it must be in during each subpass it is used in. The implementation then must execute layout transitions between subpasses in order to guarantee that the images are in the layouts required by each subpass, and in the final layout at the end of the render pass.
Automatic layout transitions apply to the entire image subresource attached to the framebuffer. If the attachment view is a 2D or 2D array view of a 3D image, even if the attachment view only refers to a subset of the slices of the selected mip level of the 3D image, automatic layout transitions apply to the entire subresource referenced which is the entire mip level in this case.
Automatic layout transitions away from the layout used in a subpass
happen-after the availability operations for all dependencies with that
subpass as the srcSubpass.
Automatic layout transitions into the layout used in a subpass happen-before
the visibility operations for all dependencies with that subpass as the
dstSubpass.
Automatic layout transitions away from initialLayout happens-after the
availability operations for all dependencies with a srcSubpass equal
to VK_SUBPASS_EXTERNAL, where dstSubpass uses the attachment
that will be transitioned.
For attachments created with VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT,
automatic layout transitions away from initialLayout happen-after the
availability operations for all dependencies with a srcSubpass equal
to VK_SUBPASS_EXTERNAL, where dstSubpass uses any aliased
attachment.
Automatic layout transitions into finalLayout happens-before the
visibility operations for all dependencies with a dstSubpass equal to
VK_SUBPASS_EXTERNAL, where srcSubpass uses the attachment that
will be transitioned.
For attachments created with VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT,
automatic layout transitions into finalLayout happen-before the
visibility operations for all dependencies with a dstSubpass equal to
VK_SUBPASS_EXTERNAL, where srcSubpass uses any aliased
attachment.
The image layout of the depth aspect of a depth/stencil attachment referring
to an image created with
VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT is dependent
on the last sample locations used to render to the attachment, thus
automatic layout transitions use the sample locations state specified in
VkRenderPassSampleLocationsBeginInfoEXT.
Automatic layout transitions of an attachment referring to a depth/stencil
image created with
VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT use the
sample locations the image subresource range referenced by the attachment
was last rendered with.
If the current render pass does not use the attachment as a depth/stencil
attachment in any subpass that happens-before, the automatic layout
transition uses the sample locations state specified in the
sampleLocationsInfo member of the element of the
VkRenderPassSampleLocationsBeginInfoEXT::pAttachmentInitialSampleLocations
array for which the attachmentIndex member equals the attachment index
of the attachment, if one is specified.
Otherwise, the automatic layout transition uses the sample locations state
specified in the sampleLocationsInfo member of the element of the
VkRenderPassSampleLocationsBeginInfoEXT::pPostSubpassSampleLocations
array for which the subpassIndex member equals the index of the
subpass that last used the attachment as a depth/stencil attachment, if one
is specified.
If no sample locations state has been specified for an automatic layout
transition performed on an attachment referring to a depth/stencil image
created with VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT
the contents of the depth aspect of the depth/stencil attachment become
undefined as if the layout of the attachment was transitioned from the
VK_IMAGE_LAYOUT_UNDEFINED layout.
If two subpasses use the same attachment in different layouts, and both layouts are read-only, no subpass dependency needs to be specified between those subpasses. If an implementation treats those layouts separately, it must insert an implicit subpass dependency between those subpasses to separate the uses in each layout. The subpass dependency operates as if defined with the following parameters:
// Used for input attachments
VkPipelineStageFlags inputAttachmentStages = VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT;
VkAccessFlags inputAttachmentAccess = VK_ACCESS_INPUT_ATTACHMENT_READ_BIT;
// Used for depth/stencil attachments
VkPipelineStageFlags depthStencilAttachmentStages = VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT | VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT;
VkAccessFlags depthStencilAttachmentAccess = VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BIT;
VkSubpassDependency implicitDependency = {
.srcSubpass = firstSubpass;
.dstSubpass = secondSubpass;
.srcStageMask = inputAttachmentStages | depthStencilAttachmentStages;
.dstStageMask = inputAttachmentStages | depthStencilAttachmentStages;
.srcAccessMask = inputAttachmentAccess | depthStencilAttachmentAccess;
.dstAccessMask = inputAttachmentAccess | depthStencilAttachmentAccess;
.dependencyFlags = 0;
};
If a subpass uses the same attachment as both an input attachment and either a color attachment or a depth/stencil attachment, writes via the color or depth/stencil attachment are not automatically made visible to reads via the input attachment, causing a feedback loop, except in any of the following conditions:
-
If the color components or depth/stencil components read by the input attachment are mutually exclusive with the components written by the color or depth/stencil attachments, then there is no feedback loop. This requires the graphics pipelines used by the subpass to disable writes to color components that are read as inputs via the
colorWriteMask, and to disable writes to depth/stencil components that are read as inputs viadepthWriteEnableorstencilTestEnable. -
If the attachment is used as an input attachment and depth/stencil attachment only, and the depth/stencil attachment is not written to.
-
If a memory dependency is inserted between when the attachment is written and when it is subsequently read by later fragments. Pipeline barriers expressing a subpass self-dependency are the only way to achieve this, and one must be inserted every time a fragment will read values at a particular sample (x, y, layer, sample) coordinate, if those values have been written since the most recent pipeline barrier; or the since start of the subpass if there have been no pipeline barriers since the start of the subpass.
An attachment used as both an input attachment and a color attachment must
be in the
VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR or
VK_IMAGE_LAYOUT_GENERAL layout.
An attachment used as an input attachment and depth/stencil attachment must
be in the
VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR,
VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL,
VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL,
VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL, or
VK_IMAGE_LAYOUT_GENERAL layout.
An attachment must not be used as both a depth/stencil attachment and a
color attachment.
To destroy a render pass, call:
void vkDestroyRenderPass(
VkDevice device,
VkRenderPass renderPass,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the render pass. -
renderPassis the handle of the render pass to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
7.2. Render Pass Compatibility
Framebuffers and graphics pipelines are created based on a specific render pass object. They must only be used with that render pass object, or one compatible with it.
Two attachment references are compatible if they have matching format and
sample count, or are both VK_ATTACHMENT_UNUSED or the pointer that
would contain the reference is NULL.
Two arrays of attachment references are compatible if all corresponding
pairs of attachments are compatible.
If the arrays are of different lengths, attachment references not present in
the smaller array are treated as VK_ATTACHMENT_UNUSED.
Two render passes are compatible if their corresponding color, input, resolve, and depth/stencil attachment references are compatible and if they are otherwise identical except for:
-
Initial and final image layout in attachment descriptions
-
Load and store operations in attachment descriptions
-
Image layout in attachment references
A framebuffer is compatible with a render pass if it was created using the same render pass or a compatible render pass.
7.3. Framebuffers
Render passes operate in conjunction with framebuffers. Framebuffers represent a collection of specific memory attachments that a render pass instance uses.
Framebuffers are represented by VkFramebuffer handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkFramebuffer)
To create a framebuffer, call:
VkResult vkCreateFramebuffer(
VkDevice device,
const VkFramebufferCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkFramebuffer* pFramebuffer);
-
deviceis the logical device that creates the framebuffer. -
pCreateInfopoints to a VkFramebufferCreateInfo structure which describes additional information about framebuffer creation. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pFramebufferpoints to aVkFramebufferhandle in which the resulting framebuffer object is returned.
The VkFramebufferCreateInfo structure is defined as:
typedef struct VkFramebufferCreateInfo {
VkStructureType sType;
const void* pNext;
VkFramebufferCreateFlags flags;
VkRenderPass renderPass;
uint32_t attachmentCount;
const VkImageView* pAttachments;
uint32_t width;
uint32_t height;
uint32_t layers;
} VkFramebufferCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
renderPassis a render pass that defines what render passes the framebuffer will be compatible with. See Render Pass Compatibility for details. -
attachmentCountis the number of attachments. -
pAttachmentsis an array ofVkImageViewhandles, each of which will be used as the corresponding attachment in a render pass instance. -
width,heightandlayersdefine the dimensions of the framebuffer. If the render pass uses multiview, thenlayersmust be one and each attachment requires a number of layers that is greater than the maximum bit index set in the view mask in the subpasses in which it is used.
Applications must ensure that all accesses to memory that backs image subresources used as attachments in a given renderpass instance either happen-before the load operations for those attachments, or happen-after the store operations for those attachments.
For depth/stencil attachments, each aspect can be used separately as
attachments and non-attachments as long as the non-attachment accesses are
also via an image subresource in either the
VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL layout or
the VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL layout,
and the attachment resource uses whichever of those two layouts the image
accesses do not.
Use of non-attachment aspects in this case is only well defined if the
attachment is used in the subpass where the non-attachment access is being
made, or the layout of the image subresource is constant throughout the
entire render pass instance, including the initialLayout and
finalLayout.
|
Note
These restrictions mean that the render pass has full knowledge of all uses of all of the attachments, so that the implementation is able to make correct decisions about when and how to perform layout transitions, when to overlap execution of subpasses, etc. |
It is legal for a subpass to use no color or depth/stencil attachments, and
rather use shader side effects such as image stores and atomics to produce
an output.
In this case, the subpass continues to use the width, height,
and layers of the framebuffer to define the dimensions of the
rendering area, and the rasterizationSamples from each pipeline’s
VkPipelineMultisampleStateCreateInfo to define the number of samples
used in rasterization; however, if
VkPhysicalDeviceFeatures::variableMultisampleRate is
VK_FALSE, then all pipelines to be bound with a given zero-attachment
subpass must have the same value for
VkPipelineMultisampleStateCreateInfo::rasterizationSamples.
typedef VkFlags VkFramebufferCreateFlags;
VkFramebufferCreateFlags is a bitmask type for setting a mask, but is
currently reserved for future use.
To destroy a framebuffer, call:
void vkDestroyFramebuffer(
VkDevice device,
VkFramebuffer framebuffer,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the framebuffer. -
framebufferis the handle of the framebuffer to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
7.4. Render Pass Commands
An application records the commands for a render pass instance one subpass at a time, by beginning a render pass instance, iterating over the subpasses to record commands for that subpass, and then ending the render pass instance.
To begin a render pass instance, call:
void vkCmdBeginRenderPass(
VkCommandBuffer commandBuffer,
const VkRenderPassBeginInfo* pRenderPassBegin,
VkSubpassContents contents);
-
commandBufferis the command buffer in which to record the command. -
pRenderPassBeginis a pointer to a VkRenderPassBeginInfo structure (defined below) which specifies the render pass to begin an instance of, and the framebuffer the instance uses. -
contentsis a VkSubpassContents value specifying how the commands in the first subpass will be provided.
After beginning a render pass instance, the command buffer is ready to record the commands for the first subpass of that render pass.
The VkRenderPassBeginInfo structure is defined as:
typedef struct VkRenderPassBeginInfo {
VkStructureType sType;
const void* pNext;
VkRenderPass renderPass;
VkFramebuffer framebuffer;
VkRect2D renderArea;
uint32_t clearValueCount;
const VkClearValue* pClearValues;
} VkRenderPassBeginInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
renderPassis the render pass to begin an instance of. -
framebufferis the framebuffer containing the attachments that are used with the render pass. -
renderAreais the render area that is affected by the render pass instance, and is described in more detail below. -
clearValueCountis the number of elements inpClearValues. -
pClearValuesis an array of VkClearValue structures that contains clear values for each attachment, if the attachment uses aloadOpvalue ofVK_ATTACHMENT_LOAD_OP_CLEARor if the attachment has a depth/stencil format and uses astencilLoadOpvalue ofVK_ATTACHMENT_LOAD_OP_CLEAR. The array is indexed by attachment number. Only elements corresponding to cleared attachments are used. Other elements ofpClearValuesare ignored.
renderArea is the render area that is affected by the render pass
instance.
The effects of attachment load, store and multisample resolve operations are
restricted to the pixels whose x and y coordinates fall within the render
area on all attachments.
The render area extends to all layers of framebuffer.
The application must ensure (using scissor if necessary) that all rendering
is contained within the render area, otherwise the pixels outside of the
render area become undefined and shader side effects may occur for
fragments outside the render area.
The render area must be contained within the framebuffer dimensions.
When multiview is enabled, the resolve operation at the end of a subpass applies to all views in the view mask.
|
Note
There may be a performance cost for using a render area smaller than the framebuffer, unless it matches the render area granularity for the render pass. |
The image layout of the depth aspect of a depth/stencil attachment referring
to an image created with
VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT is dependent
on the last sample locations used to render to the image subresource, thus
preserving the contents of such depth/stencil attachments across subpass
boundaries requires the application to specify these sample locations
whenever a layout transition of the attachment may occur.
This information can be provided by chaining an instance of the
VkRenderPassSampleLocationsBeginInfoEXT structure to the pNext
chain of VkRenderPassBeginInfo.
The VkRenderPassSampleLocationsBeginInfoEXT structure is defined as:
typedef struct VkRenderPassSampleLocationsBeginInfoEXT {
VkStructureType sType;
const void* pNext;
uint32_t attachmentInitialSampleLocationsCount;
const VkAttachmentSampleLocationsEXT* pAttachmentInitialSampleLocations;
uint32_t postSubpassSampleLocationsCount;
const VkSubpassSampleLocationsEXT* pPostSubpassSampleLocations;
} VkRenderPassSampleLocationsBeginInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
attachmentInitialSampleLocationsCountis the number of elements in thepAttachmentInitialSampleLocationsarray. -
pAttachmentInitialSampleLocationsis an array ofattachmentInitialSampleLocationsCountVkAttachmentSampleLocationsEXT structures specifying the attachment indices and their corresponding sample location state. Each element ofpAttachmentInitialSampleLocationscan specify the sample location state to use in the automatic layout transition performed to transition a depth/stencil attachment from the initial layout of the attachment to the image layout specified for the attachment in the first subpass using it. -
postSubpassSampleLocationsCountis the number of elements in thepPostSubpassSampleLocationsarray. -
pPostSubpassSampleLocationsis an array ofpostSubpassSampleLocationsCountVkSubpassSampleLocationsEXT structures specifying the subpass indices and their corresponding sample location state. Each element ofpPostSubpassSampleLocationscan specify the sample location state to use in the automatic layout transition performed to transition the depth/stencil attachment used by the specified subpass to the image layout specified in a dependent subpass or to the final layout of the attachment in case the specified subpass is the last subpass using that attachment. In addition, if VkPhysicalDeviceSampleLocationsPropertiesEXT::variableSampleLocationsisVK_FALSE, each element ofpPostSubpassSampleLocationsmust specify the sample location state that matches the sample locations used by all pipelines that will be bound to a command buffer during the specified subpass. IfvariableSampleLocationsisVK_TRUE, the sample locations used for rasterization do not depend onpPostSubpassSampleLocations.
The VkAttachmentSampleLocationsEXT structure is defined as:
typedef struct VkAttachmentSampleLocationsEXT {
uint32_t attachmentIndex;
VkSampleLocationsInfoEXT sampleLocationsInfo;
} VkAttachmentSampleLocationsEXT;
-
attachmentIndexis the index of the attachment for which the sample locations state is provided. -
sampleLocationsInfois the sample locations state to use for the layout transition of the given attachment from the initial layout of the attachment to the image layout specified for the attachment in the first subpass using it.
If the image referenced by the framebuffer attachment at index
attachmentIndex was not created with
VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT then the
values specified in sampleLocationsInfo are ignored.
The VkSubpassSampleLocationsEXT structure is defined as:
typedef struct VkSubpassSampleLocationsEXT {
uint32_t subpassIndex;
VkSampleLocationsInfoEXT sampleLocationsInfo;
} VkSubpassSampleLocationsEXT;
-
subpassIndexis the index of the subpass for which the sample locations state is provided. -
sampleLocationsInfois the sample locations state to use for the layout transition of the depth/stencil attachment away from the image layout the attachment is used with in the subpass specified insubpassIndex.
If the image referenced by the depth/stencil attachment used in the subpass
identified by subpassIndex was not created with
VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT or if the
subpass does not use a depth/stencil attachment, and
VkPhysicalDeviceSampleLocationsPropertiesEXT::variableSampleLocations
is VK_TRUE then the values specified in sampleLocationsInfo are
ignored.
Possible values of vkCmdBeginRenderPass::contents, specifying
how the commands in the first subpass will be provided, are:
typedef enum VkSubpassContents {
VK_SUBPASS_CONTENTS_INLINE = 0,
VK_SUBPASS_CONTENTS_SECONDARY_COMMAND_BUFFERS = 1,
} VkSubpassContents;
-
VK_SUBPASS_CONTENTS_INLINEspecifies that the contents of the subpass will be recorded inline in the primary command buffer, and secondary command buffers must not be executed within the subpass. -
VK_SUBPASS_CONTENTS_SECONDARY_COMMAND_BUFFERSspecifies that the contents are recorded in secondary command buffers that will be called from the primary command buffer, and vkCmdExecuteCommands is the only valid command on the command buffer until vkCmdNextSubpass or vkCmdEndRenderPass.
If the pNext chain of VkRenderPassBeginInfo includes a
VkDeviceGroupRenderPassBeginInfo structure, then that structure
includes a device mask and set of render areas for the render pass instance.
The VkDeviceGroupRenderPassBeginInfo structure is defined as:
typedef struct VkDeviceGroupRenderPassBeginInfo {
VkStructureType sType;
const void* pNext;
uint32_t deviceMask;
uint32_t deviceRenderAreaCount;
const VkRect2D* pDeviceRenderAreas;
} VkDeviceGroupRenderPassBeginInfo;
or the equivalent
typedef VkDeviceGroupRenderPassBeginInfo VkDeviceGroupRenderPassBeginInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
deviceMaskis the device mask for the render pass instance. -
deviceRenderAreaCountis the number of elements in thepDeviceRenderAreasarray. -
pDeviceRenderAreasis an array of structures of type VkRect2D defining the render area for each physical device.
The deviceMask serves several purposes.
It is an upper bound on the set of physical devices that can be used during
the render pass instance, and the initial device mask when the render pass
instance begins.
Render pass attachment load, store, and resolve operations only apply to
physical devices included in the device mask.
Subpass dependencies only apply to the physical devices in the device mask.
If deviceRenderAreaCount is not zero, then the elements of
pDeviceRenderAreas override the value of
VkRenderPassBeginInfo::renderArea, and provide a render area
specific to each physical device.
These render areas serve the same purpose as
VkRenderPassBeginInfo::renderArea, including controlling the
region of attachments that are cleared by VK_ATTACHMENT_LOAD_OP_CLEAR
and that are resolved into resolve attachments.
If this structure is not present, the render pass instance’s device mask is
the value of VkDeviceGroupCommandBufferBeginInfo::deviceMask.
If this structure is not present or if deviceRenderAreaCount is zero,
VkRenderPassBeginInfo::renderArea is used for all physical
devices.
To query the render area granularity, call:
void vkGetRenderAreaGranularity(
VkDevice device,
VkRenderPass renderPass,
VkExtent2D* pGranularity);
-
deviceis the logical device that owns the render pass. -
renderPassis a handle to a render pass. -
pGranularitypoints to a VkExtent2D structure in which the granularity is returned.
The conditions leading to an optimal renderArea are:
-
the
offset.xmember inrenderAreais a multiple of thewidthmember of the returned VkExtent2D (the horizontal granularity). -
the
offset.ymember inrenderAreais a multiple of theheightof the returned VkExtent2D (the vertical granularity). -
either the
offset.widthmember inrenderAreais a multiple of the horizontal granularity oroffset.x+offset.widthis equal to thewidthof theframebufferin the VkRenderPassBeginInfo. -
either the
offset.heightmember inrenderAreais a multiple of the vertical granularity oroffset.y+offset.heightis equal to theheightof theframebufferin the VkRenderPassBeginInfo.
Subpass dependencies are not affected by the render area, and apply to the entire image subresources attached to the framebuffer as specified in the description of automatic layout transitions. Similarly, pipeline barriers are valid even if their effect extends outside the render area.
To transition to the next subpass in the render pass instance after recording the commands for a subpass, call:
void vkCmdNextSubpass(
VkCommandBuffer commandBuffer,
VkSubpassContents contents);
-
commandBufferis the command buffer in which to record the command. -
contentsspecifies how the commands in the next subpass will be provided, in the same fashion as the corresponding parameter of vkCmdBeginRenderPass.
The subpass index for a render pass begins at zero when
vkCmdBeginRenderPass is recorded, and increments each time
vkCmdNextSubpass is recorded.
Moving to the next subpass automatically performs any multisample resolve
operations in the subpass being ended.
End-of-subpass multisample resolves are treated as color attachment writes
for the purposes of synchronization.
That is, they are considered to execute in the
VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT pipeline stage and their
writes are synchronized with VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT.
Synchronization between rendering within a subpass and any resolve
operations at the end of the subpass occurs automatically, without need for
explicit dependencies or pipeline barriers.
However, if the resolve attachment is also used in a different subpass, an
explicit dependency is needed.
After transitioning to the next subpass, the application can record the commands for that subpass.
To record a command to end a render pass instance after recording the commands for the last subpass, call:
void vkCmdEndRenderPass(
VkCommandBuffer commandBuffer);
-
commandBufferis the command buffer in which to end the current render pass instance.
Ending a render pass instance performs any multisample resolve operations on the final subpass.
8. Shaders
A shader specifies programmable operations that execute for each vertex, control point, tessellated vertex, primitive, fragment, or workgroup in the corresponding stage(s) of the graphics and compute pipelines.
Graphics pipelines include vertex shader execution as a result of primitive assembly, followed, if enabled, by tessellation control and evaluation shaders operating on patches, geometry shaders, if enabled, operating on primitives, and fragment shaders, if present, operating on fragments generated by Rasterization. In this specification, vertex, tessellation control, tessellation evaluation and geometry shaders are collectively referred to as vertex processing stages and occur in the logical pipeline before rasterization. The fragment shader occurs logically after rasterization.
Only the compute shader stage is included in a compute pipeline. Compute shaders operate on compute invocations in a workgroup.
Shaders can read from input variables, and read from and write to output variables. Input and output variables can be used to transfer data between shader stages, or to allow the shader to interact with values that exist in the execution environment. Similarly, the execution environment provides constants that describe capabilities.
Shader variables are associated with execution environment-provided inputs and outputs using built-in decorations in the shader. The available decorations for each stage are documented in the following subsections.
8.1. Shader Modules
Shader modules contain shader code and one or more entry points. Shaders are selected from a shader module by specifying an entry point as part of pipeline creation. The stages of a pipeline can use shaders that come from different modules. The shader code defining a shader module must be in the SPIR-V format, as described by the Vulkan Environment for SPIR-V appendix.
Shader modules are represented by VkShaderModule handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkShaderModule)
To create a shader module, call:
VkResult vkCreateShaderModule(
VkDevice device,
const VkShaderModuleCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkShaderModule* pShaderModule);
-
deviceis the logical device that creates the shader module. -
pCreateInfois a pointer to an instance of theVkShaderModuleCreateInfostructure. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pShaderModulepoints to aVkShaderModulehandle in which the resulting shader module object is returned.
Once a shader module has been created, any entry points it contains can be used in pipeline shader stages as described in Compute Pipelines and Graphics Pipelines.
If the shader stage fails to compile VK_ERROR_INVALID_SHADER_NV will
be generated and the compile log will be reported back to the application by
VK_EXT_debug_report if enabled.
The VkShaderModuleCreateInfo structure is defined as:
typedef struct VkShaderModuleCreateInfo {
VkStructureType sType;
const void* pNext;
VkShaderModuleCreateFlags flags;
size_t codeSize;
const uint32_t* pCode;
} VkShaderModuleCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
codeSizeis the size, in bytes, of the code pointed to bypCode. -
pCodepoints to code that is used to create the shader module. The type and format of the code is determined from the content of the memory addressed bypCode.
typedef VkFlags VkShaderModuleCreateFlags;
VkShaderModuleCreateFlags is a bitmask type for setting a mask, but is
currently reserved for future use.
To use a VkValidationCacheEXT to cache shader validation results, add
a VkShaderModuleValidationCacheCreateInfoEXT to the pNext chain
of the VkShaderModuleCreateInfo structure, specifying the cache object
to use.
The VkShaderModuleValidationCacheCreateInfoEXT struct is defined as:
typedef struct VkShaderModuleValidationCacheCreateInfoEXT {
VkStructureType sType;
const void* pNext;
VkValidationCacheEXT validationCache;
} VkShaderModuleValidationCacheCreateInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
validationCacheis the validation cache object from which the results of prior validation attempts will be written, and to which new validation results for this VkShaderModule will be written (if not already present).
To destroy a shader module, call:
void vkDestroyShaderModule(
VkDevice device,
VkShaderModule shaderModule,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the shader module. -
shaderModuleis the handle of the shader module to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
A shader module can be destroyed while pipelines created using its shaders are still in use.
8.2. Shader Execution
At each stage of the pipeline, multiple invocations of a shader may execute simultaneously. Further, invocations of a single shader produced as the result of different commands may execute simultaneously. The relative execution order of invocations of the same shader type is undefined. Shader invocations may complete in a different order than that in which the primitives they originated from were drawn or dispatched by the application. However, fragment shader outputs are written to attachments in rasterization order.
The relative order of invocations of different shader types is largely undefined. However, when invoking a shader whose inputs are generated from a previous pipeline stage, the shader invocations from the previous stage are guaranteed to have executed far enough to generate input values for all required inputs.
8.3. Shader Memory Access Ordering
The order in which image or buffer memory is read or written by shaders is largely undefined. For some shader types (vertex, tessellation evaluation, and in some cases, fragment), even the number of shader invocations that may perform loads and stores is undefined.
In particular, the following rules apply:
-
Vertex and tessellation evaluation shaders will be invoked at least once for each unique vertex, as defined in those sections.
-
Fragment shaders will be invoked zero or more times, as defined in that section.
-
The relative order of invocations of the same shader type are undefined. A store issued by a shader when working on primitive B might complete prior to a store for primitive A, even if primitive A is specified prior to primitive B. This applies even to fragment shaders; while fragment shader outputs are always written to the framebuffer in rasterization order, stores executed by fragment shader invocations are not.
-
The relative order of invocations of different shader types is largely undefined.
|
Note
The above limitations on shader invocation order make some forms of synchronization between shader invocations within a single set of primitives unimplementable. For example, having one invocation poll memory written by another invocation assumes that the other invocation has been launched and will complete its writes in finite time. |
Stores issued to different memory locations within a single shader invocation may not be visible to other invocations, or may not become visible in the order they were performed.
The OpMemoryBarrier instruction can be used to provide stronger
ordering of reads and writes performed by a single invocation.
OpMemoryBarrier guarantees that any memory transactions issued by the
shader invocation prior to the instruction complete prior to the memory
transactions issued after the instruction.
Memory barriers are needed for algorithms that require multiple invocations
to access the same memory and require the operations to be performed in a
partially-defined relative order.
For example, if one shader invocation does a series of writes, followed by
an OpMemoryBarrier instruction, followed by another write, then the
results of the series of writes before the barrier become visible to other
shader invocations at a time earlier or equal to when the results of the
final write become visible to those invocations.
In practice it means that another invocation that sees the results of the
final write would also see the previous writes.
Without the memory barrier, the final write may be visible before the
previous writes.
Writes that are the result of shader stores through a variable decorated
with Coherent automatically have available writes to the same buffer,
buffer view, or image view made visible to them, and are themselves
automatically made available to access by the same buffer, buffer view, or
image view.
Reads that are the result of shader loads through a variable decorated with
Coherent automatically have available writes to the same buffer, buffer
view, or image view made visible to them.
The order that coherent writes to different locations become available is
undefined, unless enforced by a memory barrier instruction or other memory
dependency.
|
Note
Explicit memory dependencies must still be used to guarantee availability and visibility for access via other buffers, buffer views, or image views. |
The built-in atomic memory transaction instructions can be used to read and
write a given memory address atomically.
While built-in atomic functions issued by multiple shader invocations are
executed in undefined order relative to each other, these functions perform
both a read and a write of a memory address and guarantee that no other
memory transaction will write to the underlying memory between the read and
write.
Atomic operations ensure automatic availability and visibility for writes
and reads in the same way as those to Coherent variables.
|
Note
Memory accesses performed on different resource descriptors with the same
memory backing may not be well-defined even with the |
|
Note
Atomics allow shaders to use shared global addresses for mutual exclusion or as counters, among other uses. |
8.4. Shader Inputs and Outputs
Data is passed into and out of shaders using variables with input or output
storage class, respectively.
User-defined inputs and outputs are connected between stages by matching
their Location decorations.
Additionally, data can be provided by or communicated to special functions
provided by the execution environment using BuiltIn decorations.
In many cases, the same BuiltIn decoration can be used in multiple
shader stages with similar meaning.
The specific behavior of variables decorated as BuiltIn is documented
in the following sections.
8.5. Vertex Shaders
Each vertex shader invocation operates on one vertex and its associated vertex attribute data, and outputs one vertex and associated data. Graphics pipelines must include a vertex shader, and the vertex shader stage is always the first shader stage in the graphics pipeline.
8.5.1. Vertex Shader Execution
A vertex shader must be executed at least once for each vertex specified by a draw command. If the subpass includes multiple views in its view mask, the shader may be invoked separately for each view. During execution, the shader is presented with the index of the vertex and instance for which it has been invoked. Input variables declared in the vertex shader are filled by the implementation with the values of vertex attributes associated with the invocation being executed.
If the same vertex is specified multiple times in a draw command (e.g. by including the same index value multiple times in an index buffer) the implementation may reuse the results of vertex shading if it can statically determine that the vertex shader invocations will produce identical results.
|
Note
It is implementation-dependent when and if results of vertex shading are
reused, and thus how many times the vertex shader will be executed.
This is true also if the vertex shader contains stores or atomic operations
(see |
8.6. Tessellation Control Shaders
The tessellation control shader is used to read an input patch provided by
the application and to produce an output patch.
Each tessellation control shader invocation operates on an input patch
(after all control points in the patch are processed by a vertex shader) and
its associated data, and outputs a single control point of the output patch
and its associated data, and can also output additional per-patch data.
The input patch is sized according to the patchControlPoints member of
VkPipelineTessellationStateCreateInfo, as part of input assembly.
The size of the output patch is controlled by the OpExecutionMode
OutputVertices specified in the tessellation control or tessellation
evaluation shaders, which must be specified in at least one of the shaders.
The size of the input and output patches must each be greater than zero and
less than or equal to
VkPhysicalDeviceLimits::maxTessellationPatchSize.
8.6.1. Tessellation Control Shader Execution
A tessellation control shader is invoked at least once for each output vertex in a patch. If the subpass includes multiple views in its view mask, the shader may be invoked separately for each view.
Inputs to the tessellation control shader are generated by the vertex
shader.
Each invocation of the tessellation control shader can read the attributes
of any incoming vertices and their associated data.
The invocations corresponding to a given patch execute logically in
parallel, with undefined relative execution order.
However, the OpControlBarrier instruction can be used to provide
limited control of the execution order by synchronizing invocations within a
patch, effectively dividing tessellation control shader execution into a set
of phases.
Tessellation control shaders will read undefined values if one invocation
reads a per-vertex or per-patch attribute written by another invocation at
any point during the same phase, or if two invocations attempt to write
different values to the same per-patch output in a single phase.
8.7. Tessellation Evaluation Shaders
The Tessellation Evaluation Shader operates on an input patch of control points and their associated data, and a single input barycentric coordinate indicating the invocation’s relative position within the subdivided patch, and outputs a single vertex and its associated data.
8.7.1. Tessellation Evaluation Shader Execution
A tessellation evaluation shader is invoked at least once for each unique vertex generated by the tessellator. If the subpass includes multiple views in its view mask, the shader may be invoked separately for each view.
8.8. Geometry Shaders
The geometry shader operates on a group of vertices and their associated data assembled from a single input primitive, and emits zero or more output primitives and the group of vertices and their associated data required for each output primitive.
8.8.1. Geometry Shader Execution
A geometry shader is invoked at least once for each primitive produced by
the tessellation stages, or at least once for each primitive generated by
primitive assembly when tessellation is not in use.
The number of geometry shader invocations per input primitive is determined
from the invocation count of the geometry shader specified by the
OpExecutionMode Invocations in the geometry shader.
If the invocation count is not specified, then a default of one invocation
is executed.
If the subpass includes multiple views in its view mask, the shader may be
invoked separately for each view.
8.9. Fragment Shaders
Fragment shaders are invoked as the result of rasterization in a graphics pipeline. Each fragment shader invocation operates on a single fragment and its associated data. With few exceptions, fragment shaders do not have access to any data associated with other fragments and are considered to execute in isolation of fragment shader invocations associated with other fragments.
8.9.1. Fragment Shader Execution
For each fragment generated by rasterization, a fragment shader may be invoked. A fragment shader must not be invoked if the Early Per-Fragment Tests cause it to have no coverage. If the subpass includes multiple views in its view mask, the shader may be invoked separately for each view.
Furthermore, if it is determined that a fragment generated as the result of rasterizing a first primitive will have its outputs entirely overwritten by a fragment generated as the result of rasterizing a second primitive in the same subpass, and the fragment shader used for the fragment has no other side effects, then the fragment shader may not be executed for the fragment from the first primitive.
Relative ordering of execution of different fragment shader invocations is not defined.
When a primitive (partially or fully) covers a pixel, the number of times the fragment shader is invoked is implementation-dependent, but must obey the following constraints:
-
Each covered sample is included in a single fragment shader invocation.
-
When sample shading is not enabled, there is at least one fragment shader invocation.
-
When sample shading is enabled, the minimum number of fragment shader invocations is as defined in Sample Shading.
When there is more than one fragment shader invocation per pixel, the association of samples to invocations is implementation-dependent.
In addition to the conditions outlined above for the invocation of a fragment shader, a fragment shader invocation may be produced as a helper invocation. A helper invocation is a fragment shader invocation that is created solely for the purposes of evaluating derivatives for use in non-helper fragment shader invocations. Stores and atomics performed by helper invocations must not have any effect on memory, and values returned by atomic instructions in helper invocations are undefined.
8.9.2. Early Fragment Tests
An explicit control is provided to allow fragment shaders to enable early
fragment tests.
If the fragment shader specifies the EarlyFragmentTests
OpExecutionMode, the per-fragment tests described in
Early Fragment Test Mode are performed prior to
fragment shader execution.
Otherwise, they are performed after fragment shader execution.
If the fragment shader additionally specifies the PostDepthCoverage
OpExecutionMode, the value of a variable decorated with the
SampleMask built-in
reflects the coverage after the early fragment tests.
Otherwise, it reflects the coverage before the early fragment tests.
8.10. Compute Shaders
Compute shaders are invoked via vkCmdDispatch and vkCmdDispatchIndirect commands. In general, they have access to similar resources as shader stages executing as part of a graphics pipeline.
Compute workloads are formed from groups of work items called workgroups and
processed by the compute shader in the current compute pipeline.
A workgroup is a collection of shader invocations that execute the same
shader, potentially in parallel.
Compute shaders execute in global workgroups which are divided into a
number of local workgroups with a size that can be set by assigning a
value to the LocalSize execution mode or via an object decorated by the
WorkgroupSize decoration.
An invocation within a local workgroup can share data with other members of
the local workgroup through shared variables and issue memory and control
flow barriers to synchronize with other members of the local workgroup.
8.11. Interpolation Decorations
Interpolation decorations control the behavior of attribute interpolation in
the fragment shader stage.
Interpolation decorations can be applied to Input storage class
variables in the fragment shader stage’s interface, and control the
interpolation behavior of those variables.
Inputs that could be interpolated can be decorated by at most one of the following decorations:
Fragment input variables decorated with neither Flat nor
NoPerspective use perspective-correct interpolation (for
lines and
polygons).
The presence of and type of interpolation is controlled by the above
interpolation decorations as well as the auxiliary decorations Centroid
and Sample.
A variable decorated with Flat will not be interpolated.
Instead, it will have the same value for every fragment within a triangle.
This value will come from a single provoking
vertex.
A variable decorated with Flat can also be decorated with
Centroid or Sample, which will mean the same thing as decorating
it only as Flat.
For fragment shader input variables decorated with neither Centroid nor
Sample, the assigned variable may be interpolated anywhere within the
pixel and a single value may be assigned to each sample within the pixel.
Centroid and Sample can be used to control the location and
frequency of the sampling of the decorated fragment shader input.
If a fragment shader input is decorated with Centroid, a single value
may be assigned to that variable for all samples in the pixel, but that
value must be interpolated to a location that lies in both the pixel and in
the primitive being rendered, including any of the pixel’s samples covered
by the primitive.
Because the location at which the variable is interpolated may be different
in neighboring pixels, and derivatives may be computed by computing
differences between neighboring pixels, derivatives of centroid-sampled
inputs may be less accurate than those for non-centroid interpolated
variables.
The PostDepthCoverage
execution mode does not affect the determination of the centroid location.
If a fragment shader input is decorated with Sample, a separate value
must be assigned to that variable for each covered sample in the pixel, and
that value must be sampled at the location of the individual sample.
When rasterizationSamples is VK_SAMPLE_COUNT_1_BIT, the pixel
center must be used for Centroid, Sample, and undecorated
attribute interpolation.
Fragment shader inputs that are signed or unsigned integers, integer
vectors, or any double-precision floating-point type must be decorated with
Flat.
When the VK_AMD_shader_explicit_vertex_parameter device extension is
enabled inputs can be also decorated with the CustomInterpAMD
interpolation decoration, including fragment shader inputs that are signed
or unsigned integers, integer vectors, or any double-precision
floating-point type.
Inputs decorated with CustomInterpAMD can only be accessed by the
extended instruction InterpolateAtVertexAMD and allows accessing the
value of the input for individual vertices of the primitive.
8.12. Static Use
A SPIR-V module declares a global object in memory using the OpVariable
instruction, which results in a pointer x to that object.
A specific entry point in a SPIR-V module is said to statically use that
object if that entry point’s call tree contains a function that contains a
memory instruction or image instruction with x as an id operand.
See the “Memory Instructions” and “Image Instructions” subsections of
section 3 “Binary Form” of the SPIR-V specification for the complete list
of SPIR-V memory instructions.
Static use is not used to control the behavior of variables with Input
and Output storage.
The effects of those variables are applied based only on whether they are
present in a shader entry point’s interface.
8.13. Invocation and Derivative Groups
An invocation group (see the subsection “Control Flow” of section 2 of
the SPIR-V specification) for a compute shader is the set of invocations in
a single local workgroup.
For graphics shaders, an invocation group is an implementation-dependent
subset of the set of shader invocations of a given shader stage which are
produced by a single drawing command.
For indirect drawing commands with drawCount greater than one,
invocations from separate draws are in distinct invocation groups.
|
Note
Because the partitioning of invocations into invocation groups is implementation-dependent and not observable, applications generally need to assume the worst case of all invocations in a draw belonging to a single invocation group. |
A derivative group (see the subsection “Control Flow” of section 2 of the SPIR-V 1.00 Revision 4 specification) for a fragment shader is the set of invocations generated by a single primitive (point, line, or triangle), including any helper invocations generated by that primitive. Derivatives are undefined for a sampled image instruction if the instruction is in flow control that is not uniform across the derivative group.
8.14. Subgroups
A subgroup (see the subsection ``Control Flow'' of section 2 of the SPIR-V 1.3 Revision 1 specification) is a set of invocations that can synchronize and share data with each other efficiently. An invocation group is partitioned into one or more subgroups.
Subgroup operations are divided into various categories as described in VkSubgroupFeatureFlagBits.
8.14.1. Basic Subgroup Operations
The basic subgroup operations allow two classes of functionality within
shaders
- elect and barrier.
Invocations within a subgroup can choose a single invocation to perform
some task for the subgroup as a whole using elect.
Invocations within a subgroup can perform a subgroup barrier to ensure the
ordering of execution or memory accesses within a subgroup.
Barriers can be performed on buffer memory accesses, WorkgroupLocal
memory accesses, and image memory accesses to ensure that any results
written are visible by other invocations within the subgroup.
An OpControlBarrier can also be used to perform a full execution
control barrier.
A full execution control barrier will ensure that each active invocation
within the subgroup reaches a point of execution before any are allowed to
continue.
8.14.2. Vote Subgroup Operations
The vote subgroup operations allow invocations within a subgroup to compare values across a subgroup. The types of votes enabled are:
-
Do all active subgroup invocations agree that an expression is true?
-
Do any active subgroup invocations evaluate an expression to true?
-
Do all active subgroup invocations have the same value of an expression?
|
Note
These operations are useful in combination with control flow in that they allow for developers to check whether conditions match across the subgroup and choose potentially faster code-paths in these cases. |
8.14.3. Arithmetic Subgroup Operations
The arithmetic subgroup operations allow invocations to perform scan and reduction operations across a subgroup. For reduction operations, each invocation in a subgroup will obtain the same result of these arithmetic operations applied across the subgroup. For scan operations, each invocation in the subgroup will perform an inclusive or exclusive scan, cumulatively applying the operation across the invocations in a subgroup in linear order. The operations supported are add, mul, min, max, and, or, xor.
8.14.4. Ballot Subgroup Operations
The ballot subgroup operations allow invocations to perform more complex votes across the subgroup. The ballot functionality allows all invocations within a subgroup to provide a boolean value and get as a result what each invocation provided as their boolean value. The broadcast functionality allows values to be broadcast from an invocation to all other invocations within the subgroup, given that the invocation to be broadcast from is known at pipeline creation time.
8.14.5. Shuffle Subgroup Operations
The shuffle subgroup operations allow invocations to read values from other invocations within a subgroup.
8.14.6. Shuffle Relative Subgroup Operations
The shuffle relative subgroup operations allow invocations to read values from other invocations within the subgroup relative to the current invocation in the group. The relative operations supported allow data to be shifted up and down through the invocations within a subgroup.
8.14.7. Clustered Subgroup Operations
The clustered subgroup operations allow invocations to perform an operation among partitions of a subgroup, such that the operation is only performed within the subgroup invocations within a partition. The partitions for clustered subgroup operations are consecutive power-of-two size groups of invocations and the cluster size must be known at pipeline creation time. The operations supported are add, mul, min, max, and, or, xor.
8.14.8. Quad Subgroup Operations
The quad subgroup operations allow clusters of 4 invocations (a quad), to share data efficiently with each other.
8.14.9. Partitioned Subgroup Operations
The partitioned subgroup operations allow invocations to perform an operation among partitions of a subgroup, such that the operation is only performed within the subgroup invocations within a partition. The partitions for partitioned subgroup operations can group the invocations into arbitrary subsets and can be computed at runtime. The operations supported are add, mul, min, max, and, or, xor.
8.15. Validation Cache
Validation cache objects allow the result of internal validation to be reused, both within a single application run and between multiple runs. Reuse within a single run is achieved by passing the same validation cache object when creating supported Vulkan objects. Reuse across runs of an application is achieved by retrieving validation cache contents in one run of an application, saving the contents, and using them to preinitialize a validation cache on a subsequent run. The contents of the validation cache objects are managed by the validation layers. Applications can manage the host memory consumed by a validation cache object and control the amount of data retrieved from a validation cache object.
Validation cache objects are represented by VkValidationCacheEXT
handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkValidationCacheEXT)
To create validation cache objects, call:
VkResult vkCreateValidationCacheEXT(
VkDevice device,
const VkValidationCacheCreateInfoEXT* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkValidationCacheEXT* pValidationCache);
-
deviceis the logical device that creates the validation cache object. -
pCreateInfois a pointer to aVkValidationCacheCreateInfoEXTstructure that contains the initial parameters for the validation cache object. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pValidationCacheis a pointer to aVkValidationCacheEXThandle in which the resulting validation cache object is returned.
|
Note
Applications can track and manage the total host memory size of a
validation cache object using the |
Once created, a validation cache can be passed to the
vkCreateShaderModule command as part of the
VkShaderModuleCreateInfo pNext chain.
If a VkShaderModuleValidationCacheCreateInfoEXT object is part of the
VkShaderModuleCreateInfo::pNext chain, and its
validationCache field is not VK_NULL_HANDLE, the implementation
will query it for possible reuse opportunities and update it with new
content.
The use of the validation cache object in these commands is internally
synchronized, and the same validation cache object can be used in multiple
threads simultaneously.
|
Note
Implementations should make every effort to limit any critical sections to
the actual accesses to the cache, which is expected to be significantly
shorter than the duration of the |
The VkValidationCacheCreateInfoEXT structure is defined as:
typedef struct VkValidationCacheCreateInfoEXT {
VkStructureType sType;
const void* pNext;
VkValidationCacheCreateFlagsEXT flags;
size_t initialDataSize;
const void* pInitialData;
} VkValidationCacheCreateInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
initialDataSizeis the number of bytes inpInitialData. IfinitialDataSizeis zero, the validation cache will initially be empty. -
pInitialDatais a pointer to previously retrieved validation cache data. If the validation cache data is incompatible (as defined below) with the device, the validation cache will be initially empty. IfinitialDataSizeis zero,pInitialDatais ignored.
typedef VkFlags VkValidationCacheCreateFlagsEXT;
VkValidationCacheCreateFlagsEXT is a bitmask type for setting a mask,
but is currently reserved for future use.
Validation cache objects can be merged using the command:
VkResult vkMergeValidationCachesEXT(
VkDevice device,
VkValidationCacheEXT dstCache,
uint32_t srcCacheCount,
const VkValidationCacheEXT* pSrcCaches);
-
deviceis the logical device that owns the validation cache objects. -
dstCacheis the handle of the validation cache to merge results into. -
srcCacheCountis the length of thepSrcCachesarray. -
pSrcCachesis an array of validation cache handles, which will be merged intodstCache. The previous contents ofdstCacheare included after the merge.
|
Note
The details of the merge operation are implementation dependent, but implementations should merge the contents of the specified validation caches and prune duplicate entries. |
Data can be retrieved from a validation cache object using the command:
VkResult vkGetValidationCacheDataEXT(
VkDevice device,
VkValidationCacheEXT validationCache,
size_t* pDataSize,
void* pData);
-
deviceis the logical device that owns the validation cache. -
validationCacheis the validation cache to retrieve data from. -
pDataSizeis a pointer to a value related to the amount of data in the validation cache, as described below. -
pDatais eitherNULLor a pointer to a buffer.
If pData is NULL, then the maximum size of the data that can be
retrieved from the validation cache, in bytes, is returned in
pDataSize.
Otherwise, pDataSize must point to a variable set by the user to the
size of the buffer, in bytes, pointed to by pData, and on return the
variable is overwritten with the amount of data actually written to
pData.
If pDataSize is less than the maximum size that can be retrieved by
the validation cache, at most pDataSize bytes will be written to
pData, and vkGetValidationCacheDataEXT will return
VK_INCOMPLETE.
Any data written to pData is valid and can be provided as the
pInitialData member of the VkValidationCacheCreateInfoEXT
structure passed to vkCreateValidationCacheEXT.
Two calls to vkGetValidationCacheDataEXT with the same parameters
must retrieve the same data unless a command that modifies the contents of
the cache is called between them.
Applications can store the data retrieved from the validation cache, and
use these data, possibly in a future run of the application, to populate new
validation cache objects.
The results of validation, however, may depend on the vendor ID, device ID,
driver version, and other details of the device.
To enable applications to detect when previously retrieved data is
incompatible with the device, the initial bytes written to pData must
be a header consisting of the following members:
| Offset | Size | Meaning |
|---|---|---|
0 |
4 |
length in bytes of the entire validation cache header written as a stream of bytes, with the least significant byte first |
4 |
4 |
a VkValidationCacheHeaderVersionEXT value written as a stream of bytes, with the least significant byte first |
8 |
|
a layer commit ID expressed as a UUID, which uniquely identifies the version of the validation layers used to generate these validation results |
The first four bytes encode the length of the entire validation cache header, in bytes. This value includes all fields in the header including the validation cache version field and the size of the length field.
The next four bytes encode the validation cache version, as described for VkValidationCacheHeaderVersionEXT. A consumer of the validation cache should use the cache version to interpret the remainder of the cache header.
If pDataSize is less than what is necessary to store this header,
nothing will be written to pData and zero will be written to
pDataSize.
Possible values of the second group of four bytes in the header returned by vkGetValidationCacheDataEXT, encoding the validation cache version, are:
typedef enum VkValidationCacheHeaderVersionEXT {
VK_VALIDATION_CACHE_HEADER_VERSION_ONE_EXT = 1,
} VkValidationCacheHeaderVersionEXT;
-
VK_VALIDATION_CACHE_HEADER_VERSION_ONE_EXTspecifies version one of the validation cache.
To destroy a validation cache, call:
void vkDestroyValidationCacheEXT(
VkDevice device,
VkValidationCacheEXT validationCache,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the validation cache object. -
validationCacheis the handle of the validation cache to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
9. Pipelines
The following figure shows a block diagram of the Vulkan pipelines. Some Vulkan commands specify geometric objects to be drawn or computational work to be performed, while others specify state controlling how objects are handled by the various pipeline stages, or control data transfer between memory organized as images and buffers. Commands are effectively sent through a processing pipeline, either a graphics pipeline or a compute pipeline.
The first stage of the graphics pipeline (Input Assembler) assembles vertices to form geometric primitives such as points, lines, and triangles, based on a requested primitive topology. In the next stage (Vertex Shader) vertices can be transformed, computing positions and attributes for each vertex. If tessellation and/or geometry shaders are supported, they can then generate multiple primitives from a single input primitive, possibly changing the primitive topology or generating additional attribute data in the process.
The final resulting primitives are clipped to a clip volume in preparation for the next stage, Rasterization. The rasterizer produces a series of framebuffer addresses and values using a two-dimensional description of a point, line segment, or triangle. Each fragment so produced is fed to the next stage (Fragment Shader) that performs operations on individual fragments before they finally alter the framebuffer. These operations include conditional updates into the framebuffer based on incoming and previously stored depth values (to effect depth buffering), blending of incoming fragment colors with stored colors, as well as masking, stenciling, and other logical operations on fragment values.
Framebuffer operations read and write the color and depth/stencil attachments of the framebuffer for a given subpass of a render pass instance. The attachments can be used as input attachments in the fragment shader in a later subpass of the same render pass.
The compute pipeline is a separate pipeline from the graphics pipeline, which operates on one-, two-, or three-dimensional workgroups which can read from and write to buffer and image memory.
This ordering is meant only as a tool for describing Vulkan, not as a strict rule of how Vulkan is implemented, and we present it only as a means to organize the various operations of the pipelines. Actual ordering guarantees between pipeline stages are explained in detail in the synchronization chapter.
Each pipeline is controlled by a monolithic object created from a description of all of the shader stages and any relevant fixed-function stages. Linking the whole pipeline together allows the optimization of shaders based on their input/outputs and eliminates expensive draw time state validation.
A pipeline object is bound to the current state using vkCmdBindPipeline. Any pipeline object state that is specified as dynamic is not applied to the current state when the pipeline object is bound, but is instead set by dynamic state setting commands.
No state, including dynamic state, is inherited from one command buffer to another.
Compute and graphics pipelines are each represented by VkPipeline
handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkPipeline)
9.1. Compute Pipelines
Compute pipelines consist of a single static compute shader stage and the pipeline layout.
The compute pipeline represents a compute shader and is created by calling
vkCreateComputePipelines with module and pName selecting
an entry point from a shader module, where that entry point defines a valid
compute shader, in the VkPipelineShaderStageCreateInfo structure
contained within the VkComputePipelineCreateInfo structure.
To create compute pipelines, call:
VkResult vkCreateComputePipelines(
VkDevice device,
VkPipelineCache pipelineCache,
uint32_t createInfoCount,
const VkComputePipelineCreateInfo* pCreateInfos,
const VkAllocationCallbacks* pAllocator,
VkPipeline* pPipelines);
-
deviceis the logical device that creates the compute pipelines. -
pipelineCacheis either VK_NULL_HANDLE, indicating that pipeline caching is disabled; or the handle of a valid pipeline cache object, in which case use of that cache is enabled for the duration of the command. -
createInfoCountis the length of thepCreateInfosandpPipelinesarrays. -
pCreateInfosis an array ofVkComputePipelineCreateInfostructures. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pPipelinesis a pointer to an array in which the resulting compute pipeline objects are returned.editing-noteTODO (Jon) - Should we say something like “the i’th element of the
pPipelinesarray is created based on the corresponding element of thepCreateInfosarray”? Also for vkCreateGraphicsPipelines below.
The VkComputePipelineCreateInfo structure is defined as:
typedef struct VkComputePipelineCreateInfo {
VkStructureType sType;
const void* pNext;
VkPipelineCreateFlags flags;
VkPipelineShaderStageCreateInfo stage;
VkPipelineLayout layout;
VkPipeline basePipelineHandle;
int32_t basePipelineIndex;
} VkComputePipelineCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis a bitmask of VkPipelineCreateFlagBits specifying how the pipeline will be generated. -
stageis a VkPipelineShaderStageCreateInfo describing the compute shader. -
layoutis the description of binding locations used by both the pipeline and descriptor sets used with the pipeline. -
basePipelineHandleis a pipeline to derive from -
basePipelineIndexis an index into thepCreateInfosparameter to use as a pipeline to derive from
The parameters basePipelineHandle and basePipelineIndex are
described in more detail in Pipeline
Derivatives.
stage points to a structure of type
VkPipelineShaderStageCreateInfo.
The VkPipelineShaderStageCreateInfo structure is defined as:
typedef struct VkPipelineShaderStageCreateInfo {
VkStructureType sType;
const void* pNext;
VkPipelineShaderStageCreateFlags flags;
VkShaderStageFlagBits stage;
VkShaderModule module;
const char* pName;
const VkSpecializationInfo* pSpecializationInfo;
} VkPipelineShaderStageCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
stageis a VkShaderStageFlagBits value specifying a single pipeline stage. -
moduleis aVkShaderModuleobject that contains the shader for this stage. -
pNameis a pointer to a null-terminated UTF-8 string specifying the entry point name of the shader for this stage. -
pSpecializationInfois a pointer to VkSpecializationInfo, as described in Specialization Constants, and can beNULL.
typedef VkFlags VkPipelineShaderStageCreateFlags;
VkPipelineShaderStageCreateFlags is a bitmask type for setting a mask,
but is currently reserved for future use.
Commands and structures which need to specify one or more shader stages do so using a bitmask whose bits correspond to stages. Bits which can be set to specify shader stages are:
typedef enum VkShaderStageFlagBits {
VK_SHADER_STAGE_VERTEX_BIT = 0x00000001,
VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT = 0x00000002,
VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT = 0x00000004,
VK_SHADER_STAGE_GEOMETRY_BIT = 0x00000008,
VK_SHADER_STAGE_FRAGMENT_BIT = 0x00000010,
VK_SHADER_STAGE_COMPUTE_BIT = 0x00000020,
VK_SHADER_STAGE_ALL_GRAPHICS = 0x0000001F,
VK_SHADER_STAGE_ALL = 0x7FFFFFFF,
} VkShaderStageFlagBits;
-
VK_SHADER_STAGE_VERTEX_BITspecifies the vertex stage. -
VK_SHADER_STAGE_TESSELLATION_CONTROL_BITspecifies the tessellation control stage. -
VK_SHADER_STAGE_TESSELLATION_EVALUATION_BITspecifies the tessellation evaluation stage. -
VK_SHADER_STAGE_GEOMETRY_BITspecifies the geometry stage. -
VK_SHADER_STAGE_FRAGMENT_BITspecifies the fragment stage. -
VK_SHADER_STAGE_COMPUTE_BITspecifies the compute stage. -
VK_SHADER_STAGE_ALL_GRAPHICSis a combination of bits used as shorthand to specify all graphics stages defined above (excluding the compute stage). -
VK_SHADER_STAGE_ALLis a combination of bits used as shorthand to specify all shader stages supported by the device, including all additional stages which are introduced by extensions.
typedef VkFlags VkShaderStageFlags;
VkShaderStageFlags is a bitmask type for setting a mask of zero or
more VkShaderStageFlagBits.
9.2. Graphics Pipelines
Graphics pipelines consist of multiple shader stages, multiple fixed-function pipeline stages, and a pipeline layout.
To create graphics pipelines, call:
VkResult vkCreateGraphicsPipelines(
VkDevice device,
VkPipelineCache pipelineCache,
uint32_t createInfoCount,
const VkGraphicsPipelineCreateInfo* pCreateInfos,
const VkAllocationCallbacks* pAllocator,
VkPipeline* pPipelines);
-
deviceis the logical device that creates the graphics pipelines. -
pipelineCacheis either VK_NULL_HANDLE, indicating that pipeline caching is disabled; or the handle of a valid pipeline cache object, in which case use of that cache is enabled for the duration of the command. -
createInfoCountis the length of thepCreateInfosandpPipelinesarrays. -
pCreateInfosis an array ofVkGraphicsPipelineCreateInfostructures. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pPipelinesis a pointer to an array in which the resulting graphics pipeline objects are returned.
The VkGraphicsPipelineCreateInfo structure includes an array of shader create info structures containing all the desired active shader stages, as well as creation info to define all relevant fixed-function stages, and a pipeline layout.
The VkGraphicsPipelineCreateInfo structure is defined as:
typedef struct VkGraphicsPipelineCreateInfo {
VkStructureType sType;
const void* pNext;
VkPipelineCreateFlags flags;
uint32_t stageCount;
const VkPipelineShaderStageCreateInfo* pStages;
const VkPipelineVertexInputStateCreateInfo* pVertexInputState;
const VkPipelineInputAssemblyStateCreateInfo* pInputAssemblyState;
const VkPipelineTessellationStateCreateInfo* pTessellationState;
const VkPipelineViewportStateCreateInfo* pViewportState;
const VkPipelineRasterizationStateCreateInfo* pRasterizationState;
const VkPipelineMultisampleStateCreateInfo* pMultisampleState;
const VkPipelineDepthStencilStateCreateInfo* pDepthStencilState;
const VkPipelineColorBlendStateCreateInfo* pColorBlendState;
const VkPipelineDynamicStateCreateInfo* pDynamicState;
VkPipelineLayout layout;
VkRenderPass renderPass;
uint32_t subpass;
VkPipeline basePipelineHandle;
int32_t basePipelineIndex;
} VkGraphicsPipelineCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis a bitmask of VkPipelineCreateFlagBits specifying how the pipeline will be generated. -
stageCountis the number of entries in thepStagesarray. -
pStagesis an array of sizestageCountstructures of type VkPipelineShaderStageCreateInfo describing the set of the shader stages to be included in the graphics pipeline. -
pVertexInputStateis a pointer to an instance of the VkPipelineVertexInputStateCreateInfo structure. -
pInputAssemblyStateis a pointer to an instance of the VkPipelineInputAssemblyStateCreateInfo structure which determines input assembly behavior, as described in Drawing Commands. -
pTessellationStateis a pointer to an instance of the VkPipelineTessellationStateCreateInfo structure, and is ignored if the pipeline does not include a tessellation control shader stage and tessellation evaluation shader stage. -
pViewportStateis a pointer to an instance of the VkPipelineViewportStateCreateInfo structure, and is ignored if the pipeline has rasterization disabled. -
pRasterizationStateis a pointer to an instance of the VkPipelineRasterizationStateCreateInfo structure. -
pMultisampleStateis a pointer to an instance of the VkPipelineMultisampleStateCreateInfo, and is ignored if the pipeline has rasterization disabled. -
pDepthStencilStateis a pointer to an instance of the VkPipelineDepthStencilStateCreateInfo structure, and is ignored if the pipeline has rasterization disabled or if the subpass of the render pass the pipeline is created against does not use a depth/stencil attachment. -
pColorBlendStateis a pointer to an instance of the VkPipelineColorBlendStateCreateInfo structure, and is ignored if the pipeline has rasterization disabled or if the subpass of the render pass the pipeline is created against does not use any color attachments. -
pDynamicStateis a pointer to VkPipelineDynamicStateCreateInfo and is used to indicate which properties of the pipeline state object are dynamic and can be changed independently of the pipeline state. This can beNULL, which means no state in the pipeline is considered dynamic. -
layoutis the description of binding locations used by both the pipeline and descriptor sets used with the pipeline. -
renderPassis a handle to a render pass object describing the environment in which the pipeline will be used; the pipeline must only be used with an instance of any render pass compatible with the one provided. See Render Pass Compatibility for more information. -
subpassis the index of the subpass in the render pass where this pipeline will be used. -
basePipelineHandleis a pipeline to derive from. -
basePipelineIndexis an index into thepCreateInfosparameter to use as a pipeline to derive from.
The parameters basePipelineHandle and basePipelineIndex are
described in more detail in Pipeline
Derivatives.
pStages points to an array of VkPipelineShaderStageCreateInfo
structures, which were previously described in Compute
Pipelines.
pDynamicState points to a structure of type
VkPipelineDynamicStateCreateInfo.
If any shader stage fails to compile,
the compile log will be reported back to the application, and
VK_ERROR_INVALID_SHADER_NV will be generated.
Possible values of the flags member of
VkGraphicsPipelineCreateInfo and VkComputePipelineCreateInfo,
specifying how a pipeline is created, are:
typedef enum VkPipelineCreateFlagBits {
VK_PIPELINE_CREATE_DISABLE_OPTIMIZATION_BIT = 0x00000001,
VK_PIPELINE_CREATE_ALLOW_DERIVATIVES_BIT = 0x00000002,
VK_PIPELINE_CREATE_DERIVATIVE_BIT = 0x00000004,
VK_PIPELINE_CREATE_VIEW_INDEX_FROM_DEVICE_INDEX_BIT = 0x00000008,
VK_PIPELINE_CREATE_DISPATCH_BASE = 0x00000010,
VK_PIPELINE_CREATE_VIEW_INDEX_FROM_DEVICE_INDEX_BIT_KHR = VK_PIPELINE_CREATE_VIEW_INDEX_FROM_DEVICE_INDEX_BIT,
VK_PIPELINE_CREATE_DISPATCH_BASE_KHR = VK_PIPELINE_CREATE_DISPATCH_BASE,
} VkPipelineCreateFlagBits;
-
VK_PIPELINE_CREATE_DISABLE_OPTIMIZATION_BITspecifies that the created pipeline will not be optimized. Using this flag may reduce the time taken to create the pipeline. -
VK_PIPELINE_CREATE_ALLOW_DERIVATIVES_BITspecifies that the pipeline to be created is allowed to be the parent of a pipeline that will be created in a subsequent call to vkCreateGraphicsPipelines or vkCreateComputePipelines. -
VK_PIPELINE_CREATE_DERIVATIVE_BITspecifies that the pipeline to be created will be a child of a previously created parent pipeline. -
VK_PIPELINE_CREATE_VIEW_INDEX_FROM_DEVICE_INDEX_BITspecifies that any shader input variables decorated asViewIndexwill be assigned values as if they were decorated asDeviceIndex. -
VK_PIPELINE_CREATE_DISPATCH_BASEspecifies that a compute pipeline can be used with vkCmdDispatchBase with a non-zero base workgroup.
It is valid to set both VK_PIPELINE_CREATE_ALLOW_DERIVATIVES_BIT and
VK_PIPELINE_CREATE_DERIVATIVE_BIT.
This allows a pipeline to be both a parent and possibly a child in a
pipeline hierarchy.
See Pipeline Derivatives for more
information.
typedef VkFlags VkPipelineCreateFlags;
VkPipelineCreateFlags is a bitmask type for setting a mask of zero or
more VkPipelineCreateFlagBits.
The VkPipelineDynamicStateCreateInfo structure is defined as:
typedef struct VkPipelineDynamicStateCreateInfo {
VkStructureType sType;
const void* pNext;
VkPipelineDynamicStateCreateFlags flags;
uint32_t dynamicStateCount;
const VkDynamicState* pDynamicStates;
} VkPipelineDynamicStateCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
dynamicStateCountis the number of elements in thepDynamicStatesarray. -
pDynamicStatesis an array of VkDynamicState values specifying which pieces of pipeline state will use the values from dynamic state commands rather than from pipeline state creation info.
typedef VkFlags VkPipelineDynamicStateCreateFlags;
VkPipelineDynamicStateCreateFlags is a bitmask type for setting a
mask, but is currently reserved for future use.
The source of different pieces of dynamic state is specified by the
VkPipelineDynamicStateCreateInfo::pDynamicStates property of the
currently active pipeline, each of whose elements must be one of the
values:
typedef enum VkDynamicState {
VK_DYNAMIC_STATE_VIEWPORT = 0,
VK_DYNAMIC_STATE_SCISSOR = 1,
VK_DYNAMIC_STATE_LINE_WIDTH = 2,
VK_DYNAMIC_STATE_DEPTH_BIAS = 3,
VK_DYNAMIC_STATE_BLEND_CONSTANTS = 4,
VK_DYNAMIC_STATE_DEPTH_BOUNDS = 5,
VK_DYNAMIC_STATE_STENCIL_COMPARE_MASK = 6,
VK_DYNAMIC_STATE_STENCIL_WRITE_MASK = 7,
VK_DYNAMIC_STATE_STENCIL_REFERENCE = 8,
VK_DYNAMIC_STATE_VIEWPORT_W_SCALING_NV = 1000087000,
VK_DYNAMIC_STATE_DISCARD_RECTANGLE_EXT = 1000099000,
VK_DYNAMIC_STATE_SAMPLE_LOCATIONS_EXT = 1000143000,
} VkDynamicState;
-
VK_DYNAMIC_STATE_VIEWPORTspecifies that thepViewportsstate inVkPipelineViewportStateCreateInfowill be ignored and must be set dynamically with vkCmdSetViewport before any draw commands. The number of viewports used by a pipeline is still specified by theviewportCountmember ofVkPipelineViewportStateCreateInfo. -
VK_DYNAMIC_STATE_SCISSORspecifies that thepScissorsstate inVkPipelineViewportStateCreateInfowill be ignored and must be set dynamically with vkCmdSetScissor before any draw commands. The number of scissor rectangles used by a pipeline is still specified by thescissorCountmember ofVkPipelineViewportStateCreateInfo. -
VK_DYNAMIC_STATE_LINE_WIDTHspecifies that thelineWidthstate inVkPipelineRasterizationStateCreateInfowill be ignored and must be set dynamically with vkCmdSetLineWidth before any draw commands that generate line primitives for the rasterizer. -
VK_DYNAMIC_STATE_DEPTH_BIASspecifies that thedepthBiasConstantFactor,depthBiasClampanddepthBiasSlopeFactorstates inVkPipelineRasterizationStateCreateInfowill be ignored and must be set dynamically with vkCmdSetDepthBias before any draws are performed withdepthBiasEnableinVkPipelineRasterizationStateCreateInfoset toVK_TRUE. -
VK_DYNAMIC_STATE_BLEND_CONSTANTSspecifies that theblendConstantsstate inVkPipelineColorBlendStateCreateInfowill be ignored and must be set dynamically with vkCmdSetBlendConstants before any draws are performed with a pipeline state withVkPipelineColorBlendAttachmentStatememberblendEnableset toVK_TRUEand any of the blend functions using a constant blend color. -
VK_DYNAMIC_STATE_DEPTH_BOUNDSspecifies that theminDepthBoundsandmaxDepthBoundsstates of VkPipelineDepthStencilStateCreateInfo will be ignored and must be set dynamically with vkCmdSetDepthBounds before any draws are performed with a pipeline state withVkPipelineDepthStencilStateCreateInfomemberdepthBoundsTestEnableset toVK_TRUE. -
VK_DYNAMIC_STATE_STENCIL_COMPARE_MASKspecifies that thecompareMaskstate inVkPipelineDepthStencilStateCreateInfofor bothfrontandbackwill be ignored and must be set dynamically with vkCmdSetStencilCompareMask before any draws are performed with a pipeline state withVkPipelineDepthStencilStateCreateInfomemberstencilTestEnableset toVK_TRUE -
VK_DYNAMIC_STATE_STENCIL_WRITE_MASKspecifies that thewriteMaskstate inVkPipelineDepthStencilStateCreateInfofor bothfrontandbackwill be ignored and must be set dynamically with vkCmdSetStencilWriteMask before any draws are performed with a pipeline state withVkPipelineDepthStencilStateCreateInfomemberstencilTestEnableset toVK_TRUE -
VK_DYNAMIC_STATE_STENCIL_REFERENCEspecifies that thereferencestate inVkPipelineDepthStencilStateCreateInfofor bothfrontandbackwill be ignored and must be set dynamically with vkCmdSetStencilReference before any draws are performed with a pipeline state withVkPipelineDepthStencilStateCreateInfomemberstencilTestEnableset toVK_TRUE -
VK_DYNAMIC_STATE_VIEWPORT_W_SCALING_NVspecifies that thepViewportScalingsstate inVkPipelineViewportWScalingStateCreateInfoNVwill be ignored and must be set dynamically with vkCmdSetViewportWScalingNV before any draws are performed with a pipeline state withVkPipelineViewportWScalingStateCreateInfomemberviewportScalingEnableset toVK_TRUE -
VK_DYNAMIC_STATE_DISCARD_RECTANGLES_EXTspecifies that thepDiscardRectanglesstate in VkPipelineDiscardRectangleStateCreateInfoEXT will be ignored and must be set dynamically with vkCmdSetDiscardRectangleEXT before any draw or clear commands. The VkDiscardRectangleModeEXT and the number of active discard rectangles is still specified by thediscardRectangleModeanddiscardRectangleCountmembers ofVkPipelineDiscardRectangleStateCreateInfoEXT. -
VK_DYNAMIC_STATE_SAMPLE_LOCATIONS_EXTspecifies that thesampleLocationsInfostate in VkPipelineSampleLocationsStateCreateInfoEXT will be ignored and must be set dynamically with vkCmdSetSampleLocationsEXT before any draw or clear commands. Enabling custom sample locations is still indicated by thesampleLocationsEnablemember ofVkPipelineSampleLocationsStateCreateInfoEXT.
9.2.1. Valid Combinations of Stages for Graphics Pipelines
If tessellation shader stages are omitted, the tessellation shading and fixed-function stages of the pipeline are skipped.
If a geometry shader is omitted, the geometry shading stage is skipped.
If a fragment shader is omitted, the results of fragment processing are undefined. Specifically, any fragment color outputs are considered to have undefined values, and the fragment depth is considered to be unmodified. This can be useful for depth-only rendering.
Presence of a shader stage in a pipeline is indicated by including a valid
VkPipelineShaderStageCreateInfo with module and pName
selecting an entry point from a shader module, where that entry point is
valid for the stage specified by stage.
Presence of some of the fixed-function stages in the pipeline is implicitly derived from enabled shaders and provided state. For example, the fixed-function tessellator is always present when the pipeline has valid Tessellation Control and Tessellation Evaluation shaders.
-
Depth/stencil-only rendering in a subpass with no color attachments
-
Active Pipeline Shader Stages
-
Vertex Shader
-
-
Required: Fixed-Function Pipeline Stages
-
-
Color-only rendering in a subpass with no depth/stencil attachment
-
Active Pipeline Shader Stages
-
Vertex Shader
-
Fragment Shader
-
-
Required: Fixed-Function Pipeline Stages
-
-
Rendering pipeline with tessellation and geometry shaders
-
Active Pipeline Shader Stages
-
Vertex Shader
-
Tessellation Control Shader
-
Tessellation Evaluation Shader
-
Geometry Shader
-
Fragment Shader
-
-
Required: Fixed-Function Pipeline Stages
-
9.3. Pipeline destruction
To destroy a graphics or compute pipeline, call:
void vkDestroyPipeline(
VkDevice device,
VkPipeline pipeline,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the pipeline. -
pipelineis the handle of the pipeline to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
9.4. Multiple Pipeline Creation
Multiple pipelines can be created simultaneously by passing an array of
VkGraphicsPipelineCreateInfo or VkComputePipelineCreateInfo
structures into the vkCreateGraphicsPipelines and
vkCreateComputePipelines commands, respectively.
Applications can group together similar pipelines to be created in a single
call, and implementations are encouraged to look for reuse opportunities
within a group-create.
When an application attempts to create many pipelines in a single command,
it is possible that some subset may fail creation.
In that case, the corresponding entries in the pPipelines output array
will be filled with VK_NULL_HANDLE values.
If any pipeline fails creation (for example, due to out of memory errors),
the vkCreate*Pipelines commands will return an error code.
The implementation will attempt to create all pipelines, and only return
VK_NULL_HANDLE values for those that actually failed.
9.5. Pipeline Derivatives
A pipeline derivative is a child pipeline created from a parent pipeline, where the child and parent are expected to have much commonality. The goal of derivative pipelines is that they be cheaper to create using the parent as a starting point, and that it be more efficient (on either host or device) to switch/bind between children of the same parent.
A derivative pipeline is created by setting the
VK_PIPELINE_CREATE_DERIVATIVE_BIT flag in the
Vk*PipelineCreateInfo structure.
If this is set, then exactly one of basePipelineHandle or
basePipelineIndex members of the structure must have a valid
handle/index, and specifies the parent pipeline.
If basePipelineHandle is used, the parent pipeline must have already
been created.
If basePipelineIndex is used, then the parent is being created in the
same command.
VK_NULL_HANDLE acts as the invalid handle for
basePipelineHandle, and -1 is the invalid index for
basePipelineIndex.
If basePipelineIndex is used, the base pipeline must appear earlier
in the array.
The base pipeline must have been created with the
VK_PIPELINE_CREATE_ALLOW_DERIVATIVES_BIT flag set.
9.6. Pipeline Cache
Pipeline cache objects allow the result of pipeline construction to be reused between pipelines and between runs of an application. Reuse between pipelines is achieved by passing the same pipeline cache object when creating multiple related pipelines. Reuse across runs of an application is achieved by retrieving pipeline cache contents in one run of an application, saving the contents, and using them to preinitialize a pipeline cache on a subsequent run. The contents of the pipeline cache objects are managed by the implementation. Applications can manage the host memory consumed by a pipeline cache object and control the amount of data retrieved from a pipeline cache object.
Pipeline cache objects are represented by VkPipelineCache handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkPipelineCache)
To create pipeline cache objects, call:
VkResult vkCreatePipelineCache(
VkDevice device,
const VkPipelineCacheCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkPipelineCache* pPipelineCache);
-
deviceis the logical device that creates the pipeline cache object. -
pCreateInfois a pointer to aVkPipelineCacheCreateInfostructure that contains the initial parameters for the pipeline cache object. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pPipelineCacheis a pointer to aVkPipelineCachehandle in which the resulting pipeline cache object is returned.
|
Note
Applications can track and manage the total host memory size of a pipeline
cache object using the |
Once created, a pipeline cache can be passed to the
vkCreateGraphicsPipelines and vkCreateComputePipelines commands.
If the pipeline cache passed into these commands is not
VK_NULL_HANDLE, the implementation will query it for possible reuse
opportunities and update it with new content.
The use of the pipeline cache object in these commands is internally
synchronized, and the same pipeline cache object can be used in multiple
threads simultaneously.
|
Note
Implementations should make every effort to limit any critical sections to
the actual accesses to the cache, which is expected to be significantly
shorter than the duration of the |
The VkPipelineCacheCreateInfo structure is defined as:
typedef struct VkPipelineCacheCreateInfo {
VkStructureType sType;
const void* pNext;
VkPipelineCacheCreateFlags flags;
size_t initialDataSize;
const void* pInitialData;
} VkPipelineCacheCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
initialDataSizeis the number of bytes inpInitialData. IfinitialDataSizeis zero, the pipeline cache will initially be empty. -
pInitialDatais a pointer to previously retrieved pipeline cache data. If the pipeline cache data is incompatible (as defined below) with the device, the pipeline cache will be initially empty. IfinitialDataSizeis zero,pInitialDatais ignored.
typedef VkFlags VkPipelineCacheCreateFlags;
VkPipelineCacheCreateFlags is a bitmask type for setting a mask, but
is currently reserved for future use.
Pipeline cache objects can be merged using the command:
VkResult vkMergePipelineCaches(
VkDevice device,
VkPipelineCache dstCache,
uint32_t srcCacheCount,
const VkPipelineCache* pSrcCaches);
-
deviceis the logical device that owns the pipeline cache objects. -
dstCacheis the handle of the pipeline cache to merge results into. -
srcCacheCountis the length of thepSrcCachesarray. -
pSrcCachesis an array of pipeline cache handles, which will be merged intodstCache. The previous contents ofdstCacheare included after the merge.
|
Note
The details of the merge operation are implementation dependent, but implementations should merge the contents of the specified pipelines and prune duplicate entries. |
Data can be retrieved from a pipeline cache object using the command:
VkResult vkGetPipelineCacheData(
VkDevice device,
VkPipelineCache pipelineCache,
size_t* pDataSize,
void* pData);
-
deviceis the logical device that owns the pipeline cache. -
pipelineCacheis the pipeline cache to retrieve data from. -
pDataSizeis a pointer to a value related to the amount of data in the pipeline cache, as described below. -
pDatais eitherNULLor a pointer to a buffer.
If pData is NULL, then the maximum size of the data that can be
retrieved from the pipeline cache, in bytes, is returned in pDataSize.
Otherwise, pDataSize must point to a variable set by the user to the
size of the buffer, in bytes, pointed to by pData, and on return the
variable is overwritten with the amount of data actually written to
pData.
If pDataSize is less than the maximum size that can be retrieved by
the pipeline cache, at most pDataSize bytes will be written to
pData, and vkGetPipelineCacheData will return
VK_INCOMPLETE.
Any data written to pData is valid and can be provided as the
pInitialData member of the VkPipelineCacheCreateInfo structure
passed to vkCreatePipelineCache.
Two calls to vkGetPipelineCacheData with the same parameters must
retrieve the same data unless a command that modifies the contents of the
cache is called between them.
Applications can store the data retrieved from the pipeline cache, and use
these data, possibly in a future run of the application, to populate new
pipeline cache objects.
The results of pipeline compiles, however, may depend on the vendor ID,
device ID, driver version, and other details of the device.
To enable applications to detect when previously retrieved data is
incompatible with the device, the initial bytes written to pData must
be a header consisting of the following members:
| Offset | Size | Meaning |
|---|---|---|
0 |
4 |
length in bytes of the entire pipeline cache header written as a stream of bytes, with the least significant byte first |
4 |
4 |
a VkPipelineCacheHeaderVersion value written as a stream of bytes, with the least significant byte first |
8 |
4 |
a vendor ID equal to
|
12 |
4 |
a device ID equal to
|
16 |
|
a pipeline cache ID equal to
|
The first four bytes encode the length of the entire pipeline cache header, in bytes. This value includes all fields in the header including the pipeline cache version field and the size of the length field.
The next four bytes encode the pipeline cache version, as described for VkPipelineCacheHeaderVersion. A consumer of the pipeline cache should use the cache version to interpret the remainder of the cache header.
If pDataSize is less than what is necessary to store this header,
nothing will be written to pData and zero will be written to
pDataSize.
Possible values of the second group of four bytes in the header returned by vkGetPipelineCacheData, encoding the pipeline cache version, are:
typedef enum VkPipelineCacheHeaderVersion {
VK_PIPELINE_CACHE_HEADER_VERSION_ONE = 1,
} VkPipelineCacheHeaderVersion;
-
VK_PIPELINE_CACHE_HEADER_VERSION_ONEspecifies version one of the pipeline cache.
To destroy a pipeline cache, call:
void vkDestroyPipelineCache(
VkDevice device,
VkPipelineCache pipelineCache,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the pipeline cache object. -
pipelineCacheis the handle of the pipeline cache to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
9.7. Specialization Constants
Specialization constants are a mechanism whereby constants in a SPIR-V
module can have their constant value specified at the time the
VkPipeline is created.
This allows a SPIR-V module to have constants that can be modified while
executing an application that uses the Vulkan API.
|
Note
Specialization constants are useful to allow a compute shader to have its local workgroup size changed at runtime by the user, for example. |
Each instance of the VkPipelineShaderStageCreateInfo structure
contains a parameter pSpecializationInfo, which can be NULL to
indicate no specialization constants, or point to a
VkSpecializationInfo structure.
The VkSpecializationInfo structure is defined as:
typedef struct VkSpecializationInfo {
uint32_t mapEntryCount;
const VkSpecializationMapEntry* pMapEntries;
size_t dataSize;
const void* pData;
} VkSpecializationInfo;
-
mapEntryCountis the number of entries in thepMapEntriesarray. -
pMapEntriesis a pointer to an array ofVkSpecializationMapEntrywhich maps constant IDs to offsets inpData. -
dataSizeis the byte size of thepDatabuffer. -
pDatacontains the actual constant values to specialize with.
pMapEntries points to a structure of type
VkSpecializationMapEntry.
The VkSpecializationMapEntry structure is defined as:
typedef struct VkSpecializationMapEntry {
uint32_t constantID;
uint32_t offset;
size_t size;
} VkSpecializationMapEntry;
-
constantIDis the ID of the specialization constant in SPIR-V. -
offsetis the byte offset of the specialization constant value within the supplied data buffer. -
sizeis the byte size of the specialization constant value within the supplied data buffer.
If a constantID value is not a specialization constant ID used in the
shader, that map entry does not affect the behavior of the pipeline.
In human readable SPIR-V:
OpDecorate %x SpecId 13 ; decorate .x component of WorkgroupSize with ID 13
OpDecorate %y SpecId 42 ; decorate .y component of WorkgroupSize with ID 42
OpDecorate %z SpecId 3 ; decorate .z component of WorkgroupSize with ID 3
OpDecorate %wgsize BuiltIn WorkgroupSize ; decorate WorkgroupSize onto constant
%i32 = OpTypeInt 32 0 ; declare an unsigned 32-bit type
%uvec3 = OpTypeVector %i32 3 ; declare a 3 element vector type of unsigned 32-bit
%x = OpSpecConstant %i32 1 ; declare the .x component of WorkgroupSize
%y = OpSpecConstant %i32 1 ; declare the .y component of WorkgroupSize
%z = OpSpecConstant %i32 1 ; declare the .z component of WorkgroupSize
%wgsize = OpSpecConstantComposite %uvec3 %x %y %z ; declare WorkgroupSize
From the above we have three specialization constants, one for each of the x, y & z elements of the WorkgroupSize vector.
Now to specialize the above via the specialization constants mechanism:
const VkSpecializationMapEntry entries[] =
{
{
13, // constantID
0 * sizeof(uint32_t), // offset
sizeof(uint32_t) // size
},
{
42, // constantID
1 * sizeof(uint32_t), // offset
sizeof(uint32_t) // size
},
{
3, // constantID
2 * sizeof(uint32_t), // offset
sizeof(uint32_t) // size
}
};
const uint32_t data[] = { 16, 8, 4 }; // our workgroup size is 16x8x4
const VkSpecializationInfo info =
{
3, // mapEntryCount
entries, // pMapEntries
3 * sizeof(uint32_t), // dataSize
data, // pData
};
Then when calling vkCreateComputePipelines, and passing the
VkSpecializationInfo we defined as the pSpecializationInfo
parameter of VkPipelineShaderStageCreateInfo, we will create a compute
pipeline with the runtime specified local workgroup size.
Another example would be that an application has a SPIR-V module that has some platform-dependent constants they wish to use.
In human readable SPIR-V:
OpDecorate %1 SpecId 0 ; decorate our signed 32-bit integer constant
OpDecorate %2 SpecId 12 ; decorate our 32-bit floating-point constant
%i32 = OpTypeInt 32 1 ; declare a signed 32-bit type
%float = OpTypeFloat 32 ; declare a 32-bit floating-point type
%1 = OpSpecConstant %i32 -1 ; some signed 32-bit integer constant
%2 = OpSpecConstant %float 0.5 ; some 32-bit floating-point constant
From the above we have two specialization constants, one is a signed 32-bit integer and the second is a 32-bit floating-point.
Now to specialize the above via the specialization constants mechanism:
struct SpecializationData {
int32_t data0;
float data1;
};
const VkSpecializationMapEntry entries[] =
{
{
0, // constantID
offsetof(SpecializationData, data0), // offset
sizeof(SpecializationData::data0) // size
},
{
12, // constantID
offsetof(SpecializationData, data1), // offset
sizeof(SpecializationData::data1) // size
}
};
SpecializationData data;
data.data0 = -42; // set the data for the 32-bit integer
data.data1 = 42.0f; // set the data for the 32-bit floating-point
const VkSpecializationInfo info =
{
2, // mapEntryCount
entries, // pMapEntries
sizeof(data), // dataSize
&data, // pData
};
It is legal for a SPIR-V module with specializations to be compiled into a pipeline where no specialization info was provided. SPIR-V specialization constants contain default values such that if a specialization is not provided, the default value will be used. In the examples above, it would be valid for an application to only specialize some of the specialization constants within the SPIR-V module, and let the other constants use their default values encoded within the OpSpecConstant declarations.
9.8. Pipeline Binding
Once a pipeline has been created, it can be bound to the command buffer using the command:
void vkCmdBindPipeline(
VkCommandBuffer commandBuffer,
VkPipelineBindPoint pipelineBindPoint,
VkPipeline pipeline);
-
commandBufferis the command buffer that the pipeline will be bound to. -
pipelineBindPointis a VkPipelineBindPoint value specifying whether to bind to the compute or graphics bind point. Binding one does not disturb the other. -
pipelineis the pipeline to be bound.
Once bound, a pipeline binding affects subsequent graphics or compute
commands in the command buffer until a different pipeline is bound to the
bind point.
The pipeline bound to VK_PIPELINE_BIND_POINT_COMPUTE controls the
behavior of vkCmdDispatch and vkCmdDispatchIndirect.
The pipeline bound to VK_PIPELINE_BIND_POINT_GRAPHICS controls the
behavior of all drawing commands.
No other commands are affected by the pipeline state.
Possible values of vkCmdBindPipeline::pipelineBindPoint,
specifying the bind point of a pipeline object, are:
typedef enum VkPipelineBindPoint {
VK_PIPELINE_BIND_POINT_GRAPHICS = 0,
VK_PIPELINE_BIND_POINT_COMPUTE = 1,
} VkPipelineBindPoint;
-
VK_PIPELINE_BIND_POINT_COMPUTEspecifies binding as a compute pipeline. -
VK_PIPELINE_BIND_POINT_GRAPHICSspecifies binding as a graphics pipeline.
9.9. Dynamic State
When a pipeline object is bound, any pipeline object state that is not specified as dynamic is applied to the command buffer state. Pipeline object state that is specified as dynamic is not applied to the command buffer state at this time. Instead, dynamic state can be modified at any time and persists for the lifetime of the command buffer, or until modified by another dynamic state setting command or another pipeline bind.
When a pipeline object is bound, the following applies to each state parameter:
-
If the state is not specified as dynamic in the new pipeline object, then that command buffer state is overwritten by the state in the new pipeline object.
-
If the state is specified as dynamic in both the new and the previous pipeline object, then that command buffer state is not disturbed.
-
If the state is specified as dynamic in the new pipeline object but is not specified as dynamic in the previous pipeline object, then that command buffer state becomes undefined. If the state is an array, then the entire array becomes undefined.
-
If the state is an array specified as dynamic in both the new and the previous pipeline object, and the array size is not the same in both pipeline objects, then that command buffer state becomes undefined.
Dynamic state setting commands must not be issued for state that is not specified as dynamic in the bound pipeline object.
Dynamic state that does not affect the result of operations can be left undefined.
|
Note
For example, if blending is disabled by the pipeline object state then the dynamic color blend constants do not need to be specified in the command buffer, even if this state is specified as dynamic in the pipeline object. |
9.10. Pipeline Shader Information
Information about a particular shader that has been compiled as part of a pipeline object can be extracted by calling:
VkResult vkGetShaderInfoAMD(
VkDevice device,
VkPipeline pipeline,
VkShaderStageFlagBits shaderStage,
VkShaderInfoTypeAMD infoType,
size_t* pInfoSize,
void* pInfo);
-
deviceis the device that createdpipeline. -
pipelineis the target of the query. -
shaderStageidentifies the particular shader within the pipeline about which information is being queried. -
infoTypedescribes what kind of information is being queried. -
pInfoSizeis a pointer to a value related to the amount of data the query returns, as described below. -
pInfois either NULL or a pointer to a buffer.
If pInfo is NULL, then the maximum size of the information that can
be retrieved about the shader, in bytes, is returned in pInfoSize.
Otherwise, pInfoSize must point to a variable set by the user to the
size of the buffer, in bytes, pointed to by pInfo, and on return the
variable is overwritten with the amount of data actually written to
pInfo.
If pInfoSize is less than the maximum size that can be retrieved by
the pipeline cache, then at most pInfoSize bytes will be written to
pInfo, and vkGetShaderInfoAMD will return VK_INCOMPLETE.
Not all information is available for every shader and implementations may
not support all kinds of information for any shader.
When a certain type of information is unavailable, the function returns
VK_ERROR_FEATURE_NOT_PRESENT.
If information is successfully and fully queried, the function will return
VK_SUCCESS.
For VK_SHADER_INFO_TYPE_STATISTICS_AMD, an instance of
VkShaderStatisticsInfoAMD will be written to the buffer pointed to by
pInfo.
This structure will be populated with statistics regarding the physical
device resources used by that shader along with other miscellaneous
information and is described in further detail below.
For VK_SHADER_INFO_TYPE_DISASSEMBLY_AMD, pInfo points to a UTF-8
null-terminated string containing human-readable disassembly.
The exact formatting and contents of the disassembly string are
vendor-specific.
The formatting and contents of all other types of information, including
VK_SHADER_INFO_TYPE_BINARY_AMD, are left to the vendor and are not
further specified by this extension.
The VkShaderStatisticsInfoAMD structure is defined as:
typedef struct VkShaderStatisticsInfoAMD {
VkShaderStageFlags shaderStageMask;
VkShaderResourceUsageAMD resourceUsage;
uint32_t numPhysicalVgprs;
uint32_t numPhysicalSgprs;
uint32_t numAvailableVgprs;
uint32_t numAvailableSgprs;
uint32_t computeWorkGroupSize[3];
} VkShaderStatisticsInfoAMD;
-
shaderStageMaskare the combination of logical shader stages contained within this shader. -
resourceUsageis an instance of VkShaderResourceUsageAMD describing internal physical device resources used by this shader. -
numPhysicalVgprsis the maximum number of vector instruction general-purpose registers (VGPRs) available to the physical device. -
numPhysicalSgprsis the maximum number of scalar instruction general-purpose registers (SGPRs) available to the physical device. -
numAvailableVgprsis the maximum limit of VGPRs made available to the shader compiler. -
numAvailableSgprsis the maximum limit of SGPRs made available to the shader compiler. -
computeWorkGroupSizeis the local workgroup size of this shader in { X, Y, Z } dimensions.
Some implementations may merge multiple logical shader stages together in a
single shader.
In such cases, shaderStageMask will contain a bitmask of all of the
stages that are active within that shader.
Consequently, if specifying those stages as input to
vkGetShaderInfoAMD, the same output information may be returned for
all such shader stage queries.
The number of available VGPRs and SGPRs (numAvailableVgprs and
numAvailableSgprs respectively) are the shader-addressable subset of
physical registers that is given as a limit to the compiler for register
assignment.
These values may further be limited by implementations due to performance
optimizations where register pressure is a bottleneck.
The VkShaderResourceUsageAMD structure is defined as:
typedef struct VkShaderResourceUsageAMD {
uint32_t numUsedVgprs;
uint32_t numUsedSgprs;
uint32_t ldsSizePerLocalWorkGroup;
size_t ldsUsageSizeInBytes;
size_t scratchMemUsageInBytes;
} VkShaderResourceUsageAMD;
-
numUsedVgprsis the number of vector instruction general-purpose registers used by this shader. -
numUsedSgprsis the number of scalar instruction general-purpose registers used by this shader. -
ldsSizePerLocalWorkGroupis the maximum local data store size per work group in bytes. -
ldsUsageSizeInBytesis the LDS usage size in bytes per work group by this shader. -
scratchMemUsageInBytesis the scratch memory usage in bytes by this shader.
10. Memory Allocation
Vulkan memory is broken up into two categories, host memory and device memory.
10.1. Host Memory
Host memory is memory needed by the Vulkan implementation for non-device-visible storage.
|
Note
This memory may be used to store the implementation’s representation and state of Vulkan objects. |
Vulkan provides applications the opportunity to perform host memory allocations on behalf of the Vulkan implementation. If this feature is not used, the implementation will perform its own memory allocations. Since most memory allocations are off the critical path, this is not meant as a performance feature. Rather, this can be useful for certain embedded systems, for debugging purposes (e.g. putting a guard page after all host allocations), or for memory allocation logging.
Allocators are provided by the application as a pointer to a
VkAllocationCallbacks structure:
typedef struct VkAllocationCallbacks {
void* pUserData;
PFN_vkAllocationFunction pfnAllocation;
PFN_vkReallocationFunction pfnReallocation;
PFN_vkFreeFunction pfnFree;
PFN_vkInternalAllocationNotification pfnInternalAllocation;
PFN_vkInternalFreeNotification pfnInternalFree;
} VkAllocationCallbacks;
-
pUserDatais a value to be interpreted by the implementation of the callbacks. When any of the callbacks inVkAllocationCallbacksare called, the Vulkan implementation will pass this value as the first parameter to the callback. This value can vary each time an allocator is passed into a command, even when the same object takes an allocator in multiple commands. -
pfnAllocationis a pointer to an application-defined memory allocation function of type PFN_vkAllocationFunction. -
pfnReallocationis a pointer to an application-defined memory reallocation function of type PFN_vkReallocationFunction. -
pfnFreeis a pointer to an application-defined memory free function of type PFN_vkFreeFunction. -
pfnInternalAllocationis a pointer to an application-defined function that is called by the implementation when the implementation makes internal allocations, and it is of type PFN_vkInternalAllocationNotification. -
pfnInternalFreeis a pointer to an application-defined function that is called by the implementation when the implementation frees internal allocations, and it is of type PFN_vkInternalFreeNotification.
The type of pfnAllocation is:
typedef void* (VKAPI_PTR *PFN_vkAllocationFunction)(
void* pUserData,
size_t size,
size_t alignment,
VkSystemAllocationScope allocationScope);
-
pUserDatais the value specified for VkAllocationCallbacks::pUserDatain the allocator specified by the application. -
sizeis the size in bytes of the requested allocation. -
alignmentis the requested alignment of the allocation in bytes and must be a power of two. -
allocationScopeis a VkSystemAllocationScope value specifying the allocation scope of the lifetime of the allocation, as described here.
If pfnAllocation is unable to allocate the requested memory, it must
return NULL.
If the allocation was successful, it must return a valid pointer to memory
allocation containing at least size bytes, and with the pointer value
being a multiple of alignment.
|
Note
Correct Vulkan operation cannot be assumed if the application does not follow these rules. For example, |
If pfnAllocation returns NULL, and if the implementation is unable
to continue correct processing of the current command without the requested
allocation, it must treat this as a run-time error, and generate
VK_ERROR_OUT_OF_HOST_MEMORY at the appropriate time for the command in
which the condition was detected, as described in Return Codes.
If the implementation is able to continue correct processing of the current
command without the requested allocation, then it may do so, and must not
generate VK_ERROR_OUT_OF_HOST_MEMORY as a result of this failed
allocation.
The type of pfnReallocation is:
typedef void* (VKAPI_PTR *PFN_vkReallocationFunction)(
void* pUserData,
void* pOriginal,
size_t size,
size_t alignment,
VkSystemAllocationScope allocationScope);
-
pUserDatais the value specified for VkAllocationCallbacks::pUserDatain the allocator specified by the application. -
pOriginalmust be eitherNULLor a pointer previously returned bypfnReallocationorpfnAllocationof the same allocator. -
sizeis the size in bytes of the requested allocation. -
alignmentis the requested alignment of the allocation in bytes and must be a power of two. -
allocationScopeis a VkSystemAllocationScope value specifying the allocation scope of the lifetime of the allocation, as described here.
pfnReallocation must return an allocation with enough space for
size bytes, and the contents of the original allocation from bytes
zero to min(original size, new size) - 1 must be preserved in the
returned allocation.
If size is larger than the old size, the contents of the additional
space are undefined.
If satisfying these requirements involves creating a new allocation, then
the old allocation should be freed.
If pOriginal is NULL, then pfnReallocation must behave
equivalently to a call to PFN_vkAllocationFunction with the same
parameter values (without pOriginal).
If size is zero, then pfnReallocation must behave equivalently
to a call to PFN_vkFreeFunction with the same pUserData
parameter value, and pMemory equal to pOriginal.
If pOriginal is non-NULL, the implementation must ensure that
alignment is equal to the alignment used to originally allocate
pOriginal.
If this function fails and pOriginal is non-NULL the application
must not free the old allocation.
pfnReallocation must follow the same
rules for return values as
PFN_vkAllocationFunction.
The type of pfnFree is:
typedef void (VKAPI_PTR *PFN_vkFreeFunction)(
void* pUserData,
void* pMemory);
-
pUserDatais the value specified for VkAllocationCallbacks::pUserDatain the allocator specified by the application. -
pMemoryis the allocation to be freed.
pMemory may be NULL, which the callback must handle safely.
If pMemory is non-NULL, it must be a pointer previously allocated
by pfnAllocation or pfnReallocation.
The application should free this memory.
The type of pfnInternalAllocation is:
typedef void (VKAPI_PTR *PFN_vkInternalAllocationNotification)(
void* pUserData,
size_t size,
VkInternalAllocationType allocationType,
VkSystemAllocationScope allocationScope);
-
pUserDatais the value specified for VkAllocationCallbacks::pUserDatain the allocator specified by the application. -
sizeis the requested size of an allocation. -
allocationTypeis a VkInternalAllocationType value specifying the requested type of an allocation. -
allocationScopeis a VkSystemAllocationScope value specifying the allocation scope of the lifetime of the allocation, as described here.
This is a purely informational callback.
The type of pfnInternalFree is:
typedef void (VKAPI_PTR *PFN_vkInternalFreeNotification)(
void* pUserData,
size_t size,
VkInternalAllocationType allocationType,
VkSystemAllocationScope allocationScope);
-
pUserDatais the value specified for VkAllocationCallbacks::pUserDatain the allocator specified by the application. -
sizeis the requested size of an allocation. -
allocationTypeis a VkInternalAllocationType value specifying the requested type of an allocation. -
allocationScopeis a VkSystemAllocationScope value specifying the allocation scope of the lifetime of the allocation, as described here.
Each allocation has an allocation scope which defines its lifetime and
which object it is associated with.
Possible values passed to the allocationScope parameter of the
callback functions specified by VkAllocationCallbacks, indicating the
allocation scope, are:
typedef enum VkSystemAllocationScope {
VK_SYSTEM_ALLOCATION_SCOPE_COMMAND = 0,
VK_SYSTEM_ALLOCATION_SCOPE_OBJECT = 1,
VK_SYSTEM_ALLOCATION_SCOPE_CACHE = 2,
VK_SYSTEM_ALLOCATION_SCOPE_DEVICE = 3,
VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE = 4,
} VkSystemAllocationScope;
-
VK_SYSTEM_ALLOCATION_SCOPE_COMMANDspecifies that the allocation is scoped to the duration of the Vulkan command. -
VK_SYSTEM_ALLOCATION_SCOPE_OBJECTspecifies that the allocation is scoped to the lifetime of the Vulkan object that is being created or used. -
VK_SYSTEM_ALLOCATION_SCOPE_CACHEspecifies that the allocation is scoped to the lifetime of aVkPipelineCacheorVkValidationCacheEXTobject. -
VK_SYSTEM_ALLOCATION_SCOPE_DEVICEspecifies that the allocation is scoped to the lifetime of the Vulkan device. -
VK_SYSTEM_ALLOCATION_SCOPE_INSTANCEspecifies that the allocation is scoped to the lifetime of the Vulkan instance.
Most Vulkan commands operate on a single object, or there is a sole object
that is being created or manipulated.
When an allocation uses an allocation scope of
VK_SYSTEM_ALLOCATION_SCOPE_OBJECT or
VK_SYSTEM_ALLOCATION_SCOPE_CACHE, the allocation is scoped to the
object being created or manipulated.
When an implementation requires host memory, it will make callbacks to the application using the most specific allocator and allocation scope available:
-
If an allocation is scoped to the duration of a command, the allocator will use the
VK_SYSTEM_ALLOCATION_SCOPE_COMMANDallocation scope. The most specific allocator available is used: if the object being created or manipulated has an allocator, that object’s allocator will be used, else if the parentVkDevicehas an allocator it will be used, else if the parentVkInstancehas an allocator it will be used. Else, -
If an allocation is associated with an object of type
VkValidationCacheEXTorVkPipelineCache, the allocator will use theVK_SYSTEM_ALLOCATION_SCOPE_CACHEallocation scope. The most specific allocator available is used (cache, else device, else instance). Else, -
If an allocation is scoped to the lifetime of an object, that object is being created or manipulated by the command, and that object’s type is not
VkDeviceorVkInstance, the allocator will use an allocation scope ofVK_SYSTEM_ALLOCATION_SCOPE_OBJECT. The most specific allocator available is used (object, else device, else instance). Else, -
If an allocation is scoped to the lifetime of a device, the allocator will use an allocation scope of
VK_SYSTEM_ALLOCATION_SCOPE_DEVICE. The most specific allocator available is used (device, else instance). Else, -
If the allocation is scoped to the lifetime of an instance and the instance has an allocator, its allocator will be used with an allocation scope of
VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE. -
Otherwise an implementation will allocate memory through an alternative mechanism that is unspecified.
Objects that are allocated from pools do not specify their own allocator. When an implementation requires host memory for such an object, that memory is sourced from the object’s parent pool’s allocator.
The application is not expected to handle allocating memory that is intended
for execution by the host due to the complexities of differing security
implementations across multiple platforms.
The implementation will allocate such memory internally and invoke an
application provided informational callback when these internal
allocations are allocated and freed.
Upon allocation of executable memory, pfnInternalAllocation will be
called.
Upon freeing executable memory, pfnInternalFree will be called.
An implementation will only call an informational callback for executable
memory allocations and frees.
The allocationType parameter to the pfnInternalAllocation and
pfnInternalFree functions may be one of the following values:
typedef enum VkInternalAllocationType {
VK_INTERNAL_ALLOCATION_TYPE_EXECUTABLE = 0,
} VkInternalAllocationType;
-
VK_INTERNAL_ALLOCATION_TYPE_EXECUTABLEspecifies that the allocation is intended for execution by the host.
An implementation must only make calls into an application-provided allocator during the execution of an API command. An implementation must only make calls into an application-provided allocator from the same thread that called the provoking API command. The implementation should not synchronize calls to any of the callbacks. If synchronization is needed, the callbacks must provide it themselves. The informational callbacks are subject to the same restrictions as the allocation callbacks.
If an implementation intends to make calls through an
VkAllocationCallbacks structure between the time a vkCreate*
command returns and the time a corresponding vkDestroy* command
begins, that implementation must save a copy of the allocator before the
vkCreate* command returns.
The callback functions and any data structures they rely upon must remain
valid for the lifetime of the object they are associated with.
If an allocator is provided to a vkCreate* command, a compatible
allocator must be provided to the corresponding vkDestroy* command.
Two VkAllocationCallbacks structures are compatible if memory
allocated with pfnAllocation or pfnReallocation in each can be
freed with pfnReallocation or pfnFree in the other.
An allocator must not be provided to a vkDestroy* command if an
allocator was not provided to the corresponding vkCreate* command.
If a non-NULL allocator is used, the pfnAllocation,
pfnReallocation and pfnFree members must be non-NULL and
point to valid implementations of the callbacks.
An application can choose to not provide informational callbacks by setting
both pfnInternalAllocation and pfnInternalFree to NULL.
pfnInternalAllocation and pfnInternalFree must either both be
NULL or both be non-NULL.
If pfnAllocation or pfnReallocation fail, the implementation
may fail object creation and/or generate an
VK_ERROR_OUT_OF_HOST_MEMORY error, as appropriate.
Allocation callbacks must not call any Vulkan commands.
The following sets of rules define when an implementation is permitted to call the allocator callbacks.
pfnAllocation or pfnReallocation may be called in the following
situations:
-
Allocations scoped to a
VkDeviceorVkInstancemay be allocated from any API command. -
Allocations scoped to a command may be allocated from any API command.
-
Allocations scoped to a
VkPipelineCachemay only be allocated from:-
vkCreatePipelineCache -
vkMergePipelineCachesfordstCache -
vkCreateGraphicsPipelinesforpipelineCache -
vkCreateComputePipelinesforpipelineCache
-
-
Allocations scoped to a
VkValidationCacheEXTmay only be allocated from:-
vkCreateValidationCacheEXT -
vkMergeValidationCachesEXTfordstCache -
vkCreateShaderModuleforvalidationCacheinVkShaderModuleValidationCacheCreateInfoEXT
-
-
Allocations scoped to a
VkDescriptorPoolmay only be allocated from:-
any command that takes the pool as a direct argument
-
vkAllocateDescriptorSetsfor thedescriptorPoolmember of itspAllocateInfoparameter -
vkCreateDescriptorPool
-
-
Allocations scoped to a
VkCommandPoolmay only be allocated from:-
any command that takes the pool as a direct argument
-
vkCreateCommandPool -
vkAllocateCommandBuffersfor thecommandPoolmember of itspAllocateInfoparameter -
any
vkCmd*command whosecommandBufferwas allocated from thatVkCommandPool
-
-
Allocations scoped to any other object may only be allocated in that object’s
vkCreate*command.
pfnFree may be called in the following situations:
-
Allocations scoped to a
VkDeviceorVkInstancemay be freed from any API command. -
Allocations scoped to a command must be freed by any API command which allocates such memory.
-
Allocations scoped to a
VkPipelineCachemay be freed fromvkDestroyPipelineCache. -
Allocations scoped to a
VkValidationCacheEXTmay be freed fromvkDestroyValidationCacheEXT. -
Allocations scoped to a
VkDescriptorPoolmay be freed from-
any command that takes the pool as a direct argument
-
-
Allocations scoped to a
VkCommandPoolmay be freed from:-
any command that takes the pool as a direct argument
-
vkResetCommandBufferwhosecommandBufferwas allocated from thatVkCommandPool
-
-
Allocations scoped to any other object may be freed in that object’s
vkDestroy*command. -
Any command that allocates host memory may also free host memory of the same scope.
10.2. Device Memory
Device memory is memory that is visible to the device — for example the contents of the image or buffer objects, which can be natively used by the device.
Memory properties of a physical device describe the memory heaps and memory types available.
To query memory properties, call:
void vkGetPhysicalDeviceMemoryProperties(
VkPhysicalDevice physicalDevice,
VkPhysicalDeviceMemoryProperties* pMemoryProperties);
-
physicalDeviceis the handle to the device to query. -
pMemoryPropertiespoints to an instance ofVkPhysicalDeviceMemoryPropertiesstructure in which the properties are returned.
The VkPhysicalDeviceMemoryProperties structure is defined as:
typedef struct VkPhysicalDeviceMemoryProperties {
uint32_t memoryTypeCount;
VkMemoryType memoryTypes[VK_MAX_MEMORY_TYPES];
uint32_t memoryHeapCount;
VkMemoryHeap memoryHeaps[VK_MAX_MEMORY_HEAPS];
} VkPhysicalDeviceMemoryProperties;
-
memoryTypeCountis the number of valid elements in thememoryTypesarray. -
memoryTypesis an array of VkMemoryType structures describing the memory types that can be used to access memory allocated from the heaps specified bymemoryHeaps. -
memoryHeapCountis the number of valid elements in thememoryHeapsarray. -
memoryHeapsis an array of VkMemoryHeap structures describing the memory heaps from which memory can be allocated.
The VkPhysicalDeviceMemoryProperties structure describes a number of
memory heaps as well as a number of memory types that can be used to
access memory allocated in those heaps.
Each heap describes a memory resource of a particular size, and each memory
type describes a set of memory properties (e.g. host cached vs uncached)
that can be used with a given memory heap.
Allocations using a particular memory type will consume resources from the
heap indicated by that memory type’s heap index.
More than one memory type may share each heap, and the heaps and memory
types provide a mechanism to advertise an accurate size of the physical
memory resources while allowing the memory to be used with a variety of
different properties.
The number of memory heaps is given by memoryHeapCount and is less
than or equal to VK_MAX_MEMORY_HEAPS.
Each heap is described by an element of the memoryHeaps array as a
VkMemoryHeap structure.
The number of memory types available across all memory heaps is given by
memoryTypeCount and is less than or equal to
VK_MAX_MEMORY_TYPES.
Each memory type is described by an element of the memoryTypes array
as a VkMemoryType structure.
At least one heap must include VK_MEMORY_HEAP_DEVICE_LOCAL_BIT in
VkMemoryHeap::flags.
If there are multiple heaps that all have similar performance
characteristics, they may all include
VK_MEMORY_HEAP_DEVICE_LOCAL_BIT.
In a unified memory architecture (UMA) system there is often only a single
memory heap which is considered to be equally “local” to the host and to
the device, and such an implementation must advertise the heap as
device-local.
Each memory type returned by vkGetPhysicalDeviceMemoryProperties must
have its propertyFlags set to one of the following values:
-
0
-
VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT|
VK_MEMORY_PROPERTY_HOST_COHERENT_BIT -
VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT|
VK_MEMORY_PROPERTY_HOST_CACHED_BIT -
VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT|
VK_MEMORY_PROPERTY_HOST_CACHED_BIT|
VK_MEMORY_PROPERTY_HOST_COHERENT_BIT -
VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT -
VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT|
VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT|
VK_MEMORY_PROPERTY_HOST_COHERENT_BIT -
VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT|
VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT|
VK_MEMORY_PROPERTY_HOST_CACHED_BIT -
VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT|
VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT|
VK_MEMORY_PROPERTY_HOST_CACHED_BIT|
VK_MEMORY_PROPERTY_HOST_COHERENT_BIT -
VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT|
VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT -
VK_MEMORY_PROPERTY_PROTECTED_BIT -
VK_MEMORY_PROPERTY_PROTECTED_BIT|VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT
There must be at least one memory type with both the
VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT and
VK_MEMORY_PROPERTY_HOST_COHERENT_BIT bits set in its
propertyFlags.
There must be at least one memory type with the
VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT bit set in its
propertyFlags.
For each pair of elements X and Y returned in memoryTypes, X
must be placed at a lower index position than Y if:
-
either the set of bit flags returned in the
propertyFlagsmember of X is a strict subset of the set of bit flags returned in thepropertyFlagsmember of Y. -
or the
propertyFlagsmembers of X and Y are equal, and X belongs to a memory heap with greater performance (as determined in an implementation-specific manner).
|
Note
There is no ordering requirement between X and Y elements for the case
their |
This ordering requirement enables applications to use a simple search loop to select the desired memory type along the lines of:
// Find a memory in `memoryTypeBitsRequirement` that includes all of `requiredProperties`
int32_t findProperties(const VkPhysicalDeviceMemoryProperties* pMemoryProperties,
uint32_t memoryTypeBitsRequirement,
VkMemoryPropertyFlags requiredProperties) {
const uint32_t memoryCount = pMemoryProperties->memoryTypeCount;
for (uint32_t memoryIndex = 0; memoryIndex < memoryCount; ++memoryIndex) {
const uint32_t memoryTypeBits = (1 << memoryIndex);
const bool isRequiredMemoryType = memoryTypeBitsRequirement & memoryTypeBits;
const VkMemoryPropertyFlags properties =
pMemoryProperties->memoryTypes[memoryIndex].propertyFlags;
const bool hasRequiredProperties =
(properties & requiredProperties) == requiredProperties;
if (isRequiredMemoryType && hasRequiredProperties)
return static_cast<int32_t>(memoryIndex);
}
// failed to find memory type
return -1;
}
// Try to find an optimal memory type, or if it does not exist try fallback memory type
// `device` is the VkDevice
// `image` is the VkImage that requires memory to be bound
// `memoryProperties` properties as returned by vkGetPhysicalDeviceMemoryProperties
// `requiredProperties` are the property flags that must be present
// `optimalProperties` are the property flags that are preferred by the application
VkMemoryRequirements memoryRequirements;
vkGetImageMemoryRequirements(device, image, &memoryRequirements);
int32_t memoryType =
findProperties(&memoryProperties, memoryRequirements.memoryTypeBits, optimalProperties);
if (memoryType == -1) // not found; try fallback properties
memoryType =
findProperties(&memoryProperties, memoryRequirements.memoryTypeBits, requiredProperties);
To query memory properties, call:
void vkGetPhysicalDeviceMemoryProperties2(
VkPhysicalDevice physicalDevice,
VkPhysicalDeviceMemoryProperties2* pMemoryProperties);
or the equivalent command
void vkGetPhysicalDeviceMemoryProperties2KHR(
VkPhysicalDevice physicalDevice,
VkPhysicalDeviceMemoryProperties2* pMemoryProperties);
-
physicalDeviceis the handle to the device to query. -
pMemoryPropertiespoints to an instance ofVkPhysicalDeviceMemoryProperties2structure in which the properties are returned.
vkGetPhysicalDeviceMemoryProperties2 behaves similarly to
vkGetPhysicalDeviceMemoryProperties, with the ability to return
extended information in a pNext chain of output structures.
The VkPhysicalDeviceMemoryProperties2 structure is defined as:
typedef struct VkPhysicalDeviceMemoryProperties2 {
VkStructureType sType;
void* pNext;
VkPhysicalDeviceMemoryProperties memoryProperties;
} VkPhysicalDeviceMemoryProperties2;
or the equivalent
typedef VkPhysicalDeviceMemoryProperties2 VkPhysicalDeviceMemoryProperties2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
memoryPropertiesis a structure of type VkPhysicalDeviceMemoryProperties which is populated with the same values as in vkGetPhysicalDeviceMemoryProperties.
The VkMemoryHeap structure is defined as:
typedef struct VkMemoryHeap {
VkDeviceSize size;
VkMemoryHeapFlags flags;
} VkMemoryHeap;
-
sizeis the total memory size in bytes in the heap. -
flagsis a bitmask of VkMemoryHeapFlagBits specifying attribute flags for the heap.
Bits which may be set in VkMemoryHeap::flags, indicating
attribute flags for the heap, are:
typedef enum VkMemoryHeapFlagBits {
VK_MEMORY_HEAP_DEVICE_LOCAL_BIT = 0x00000001,
VK_MEMORY_HEAP_MULTI_INSTANCE_BIT = 0x00000002,
VK_MEMORY_HEAP_MULTI_INSTANCE_BIT_KHR = VK_MEMORY_HEAP_MULTI_INSTANCE_BIT,
} VkMemoryHeapFlagBits;
-
VK_MEMORY_HEAP_DEVICE_LOCAL_BITspecifies that the heap corresponds to device local memory. Device local memory may have different performance characteristics than host local memory, and may support different memory property flags. -
VK_MEMORY_HEAP_MULTI_INSTANCE_BITspecifies that in a logical device representing more than one physical device, there is a per-physical device instance of the heap memory. By default, an allocation from such a heap will be replicated to each physical device’s instance of the heap.
typedef VkFlags VkMemoryHeapFlags;
VkMemoryHeapFlags is a bitmask type for setting a mask of zero or more
VkMemoryHeapFlagBits.
The VkMemoryType structure is defined as:
typedef struct VkMemoryType {
VkMemoryPropertyFlags propertyFlags;
uint32_t heapIndex;
} VkMemoryType;
-
heapIndexdescribes which memory heap this memory type corresponds to, and must be less thanmemoryHeapCountfrom the VkPhysicalDeviceMemoryProperties structure. -
propertyFlagsis a bitmask of VkMemoryPropertyFlagBits of properties for this memory type.
Bits which may be set in VkMemoryType::propertyFlags,
indicating properties of a memory heap, are:
typedef enum VkMemoryPropertyFlagBits {
VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT = 0x00000001,
VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT = 0x00000002,
VK_MEMORY_PROPERTY_HOST_COHERENT_BIT = 0x00000004,
VK_MEMORY_PROPERTY_HOST_CACHED_BIT = 0x00000008,
VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT = 0x00000010,
VK_MEMORY_PROPERTY_PROTECTED_BIT = 0x00000020,
} VkMemoryPropertyFlagBits;
-
VK_MEMORY_PROPERTY_DEVICE_LOCAL_BITbit specifies that memory allocated with this type is the most efficient for device access. This property will be set if and only if the memory type belongs to a heap with theVK_MEMORY_HEAP_DEVICE_LOCAL_BITset. -
VK_MEMORY_PROPERTY_HOST_VISIBLE_BITbit specifies that memory allocated with this type can be mapped for host access using vkMapMemory. -
VK_MEMORY_PROPERTY_HOST_COHERENT_BITbit specifies that the host cache management commands vkFlushMappedMemoryRanges and vkInvalidateMappedMemoryRanges are not needed to flush host writes to the device or make device writes visible to the host, respectively. -
VK_MEMORY_PROPERTY_HOST_CACHED_BITbit specifies that memory allocated with this type is cached on the host. Host memory accesses to uncached memory are slower than to cached memory, however uncached memory is always host coherent. -
VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BITbit specifies that the memory type only allows device access to the memory. Memory types must not have bothVK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BITandVK_MEMORY_PROPERTY_HOST_VISIBLE_BITset. Additionally, the object’s backing memory may be provided by the implementation lazily as specified in Lazily Allocated Memory. -
VK_MEMORY_PROPERTY_PROTECTED_BITbit specifies that the memory type only allows device access to the memory, and allows protected queue operations to access the memory. Memory types must not haveVK_MEMORY_PROPERTY_PROTECTED_BITset and any ofVK_MEMORY_PROPERTY_HOST_VISIBLE_BITset, orVK_MEMORY_PROPERTY_HOST_COHERENT_BITset, orVK_MEMORY_PROPERTY_HOST_CACHED_BITset.
typedef VkFlags VkMemoryPropertyFlags;
VkMemoryPropertyFlags is a bitmask type for setting a mask of zero or
more VkMemoryPropertyFlagBits.
A Vulkan device operates on data in device memory via memory objects that
are represented in the API by a VkDeviceMemory handle:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDeviceMemory)
To allocate memory objects, call:
VkResult vkAllocateMemory(
VkDevice device,
const VkMemoryAllocateInfo* pAllocateInfo,
const VkAllocationCallbacks* pAllocator,
VkDeviceMemory* pMemory);
-
deviceis the logical device that owns the memory. -
pAllocateInfois a pointer to an instance of the VkMemoryAllocateInfo structure describing parameters of the allocation. A successful returned allocation must use the requested parameters — no substitution is permitted by the implementation. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pMemoryis a pointer to aVkDeviceMemoryhandle in which information about the allocated memory is returned.
Allocations returned by vkAllocateMemory are guaranteed to meet any
alignment requirement of the implementation.
For example, if an implementation requires 128 byte alignment for images and
64 byte alignment for buffers, the device memory returned through this
mechanism would be 128-byte aligned.
This ensures that applications can correctly suballocate objects of
different types (with potentially different alignment requirements) in the
same memory object.
When memory is allocated, its contents are undefined with the following constraint:
-
The contents of unprotected memory must not be a function of data protected memory objects, even if those memory objects were previously freed.
|
Note
The contents of memory allocated by one application should not be a function of data from protected memory objects of another application, even if those memory objects were previously freed. |
The maximum number of valid memory allocations that can exist
simultaneously within a VkDevice may be restricted by implementation-
or platform-dependent limits.
If a call to vkAllocateMemory would cause the total number of
allocations to exceed these limits, such a call will fail and must return
VK_ERROR_TOO_MANY_OBJECTS.
The
maxMemoryAllocationCount
feature describes the number of allocations that can exist simultaneously
before encountering these internal limits.
Some platforms may have a limit on the maximum size of a single allocation.
For example, certain systems may fail to create allocations with a size
greater than or equal to 4GB.
Such a limit is implementation-dependent, and if such a failure occurs then
the error VK_ERROR_OUT_OF_DEVICE_MEMORY must be returned.
This limit is advertised in
VkPhysicalDeviceMaintenance3Properties::maxMemoryAllocationSize.
The VkMemoryAllocateInfo structure is defined as:
typedef struct VkMemoryAllocateInfo {
VkStructureType sType;
const void* pNext;
VkDeviceSize allocationSize;
uint32_t memoryTypeIndex;
} VkMemoryAllocateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
allocationSizeis the size of the allocation in bytes -
memoryTypeIndexis an index identifying a memory type from thememoryTypesarray of the VkPhysicalDeviceMemoryProperties structure
An instance of the VkMemoryAllocateInfo structure defines a memory
import operation if the pNext chain contains an instance of one of the
following structures:
* VkImportMemoryWin32HandleInfoKHR with non-zero handleType
value
* VkImportMemoryFdInfoKHR with a non-zero handleType value
* VkImportMemoryHostPointerInfoEXT with a non-zero handleType
value
* VkImportAndroidHardwareBufferInfoANDROID with a non-NULL
buffer value
Importing memory must not modify the content of the memory. Implementations must ensure that importing memory does not enable the importing Vulkan instance to access any memory or resources in other Vulkan instances other than that corresponding to the memory object imported. Implementations must also ensure accessing imported memory which has not been initialized does not allow the importing Vulkan instance to obtain data from the exporting Vulkan instance or vice-versa.
|
Note
How exported and imported memory is isolated is left to the implementation, but applications should be aware that such isolation may prevent implementations from placing multiple exportable memory objects in the same physical or virtual page. Hence, applications should avoid creating many small external memory objects whenever possible. |
When performing a memory import operation, it is the responsibility of the
application to ensure the external handles meet all valid usage
requirements.
However, implementations must perform sufficient validation of external
handles to ensure that the operation results in a valid memory object which
will not cause program termination, device loss, queue stalls, or corruption
of other resources when used as allowed according to its allocation
parameters.
If the external handle provided does not meet these requirements, the
implementation must fail the memory import operation with the error code
VK_ERROR_INVALID_EXTERNAL_HANDLE.
If the pNext chain includes a VkMemoryDedicatedAllocateInfo
structure, then that structure includes a handle of the sole buffer or image
resource that the memory can be bound to.
The VkMemoryDedicatedAllocateInfo structure is defined as:
typedef struct VkMemoryDedicatedAllocateInfo {
VkStructureType sType;
const void* pNext;
VkImage image;
VkBuffer buffer;
} VkMemoryDedicatedAllocateInfo;
or the equivalent
typedef VkMemoryDedicatedAllocateInfo VkMemoryDedicatedAllocateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
imageis VK_NULL_HANDLE or a handle of an image which this memory will be bound to. -
bufferis VK_NULL_HANDLE or a handle of a buffer which this memory will be bound to.
If the pNext chain includes a
VkDedicatedAllocationMemoryAllocateInfoNV structure, then that
structure includes a handle of the sole buffer or image resource that the
memory can be bound to.
The VkDedicatedAllocationMemoryAllocateInfoNV structure is defined as:
typedef struct VkDedicatedAllocationMemoryAllocateInfoNV {
VkStructureType sType;
const void* pNext;
VkImage image;
VkBuffer buffer;
} VkDedicatedAllocationMemoryAllocateInfoNV;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
imageis VK_NULL_HANDLE or a handle of an image which this memory will be bound to. -
bufferis VK_NULL_HANDLE or a handle of a buffer which this memory will be bound to.
When allocating memory that may be exported to another process or Vulkan
instance, add a VkExportMemoryAllocateInfo structure to the
pNext chain of the VkMemoryAllocateInfo structure, specifying
the handle types that may be exported.
The VkExportMemoryAllocateInfo structure is defined as:
typedef struct VkExportMemoryAllocateInfo {
VkStructureType sType;
const void* pNext;
VkExternalMemoryHandleTypeFlags handleTypes;
} VkExportMemoryAllocateInfo;
or the equivalent
typedef VkExportMemoryAllocateInfo VkExportMemoryAllocateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
handleTypesis a bitmask of VkExternalMemoryHandleTypeFlagBits specifying one or more memory handle types the application can export from the resulting allocation. The application can request multiple handle types for the same allocation.
To specify additional attributes of NT handles exported from a memory
object, add the VkExportMemoryWin32HandleInfoKHR structure to the
pNext chain of the VkMemoryAllocateInfo structure.
The VkExportMemoryWin32HandleInfoKHR structure is defined as:
typedef struct VkExportMemoryWin32HandleInfoKHR {
VkStructureType sType;
const void* pNext;
const SECURITY_ATTRIBUTES* pAttributes;
DWORD dwAccess;
LPCWSTR name;
} VkExportMemoryWin32HandleInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
pAttributesis a pointer to a WindowsSECURITY_ATTRIBUTESstructure specifying security attributes of the handle. -
dwAccessis aDWORDspecifying access rights of the handle. -
nameis a NULL-terminated UTF-16 string to associate with the underlying resource referenced by NT handles exported from the created memory.
If this structure is not present, or if pAttributes is set to NULL,
default security descriptor values will be used, and child processes created
by the application will not inherit the handle, as described in the MSDN
documentation for “Synchronization Object Security and Access Rights”1.
Further, if the structure is not present, the access rights will be
DXGI_SHARED_RESOURCE_READ | DXGI_SHARED_RESOURCE_WRITE
for handles of the following types:
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT
And
GENERIC_ALL
for handles of the following types:
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_HEAP_BIT
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT
To import memory from a Windows handle, add a
VkImportMemoryWin32HandleInfoKHR structure to the pNext chain of
the VkMemoryAllocateInfo structure.
The VkImportMemoryWin32HandleInfoKHR structure is defined as:
typedef struct VkImportMemoryWin32HandleInfoKHR {
VkStructureType sType;
const void* pNext;
VkExternalMemoryHandleTypeFlagBits handleType;
HANDLE handle;
LPCWSTR name;
} VkImportMemoryWin32HandleInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
handleTypespecifies the type ofhandleorname. -
handleis the external handle to import, orNULL. -
nameis a NULL-terminated UTF-16 string naming the underlying memory resource to import, orNULL.
Importing memory objects from Windows handles does not transfer ownership of
the handle to the Vulkan implementation.
For handle types defined as NT handles, the application must release
ownership using the CloseHandle system call when the handle is no
longer needed.
Applications can import the same underlying memory into multiple instances
of Vulkan, into the same instance from which it was exported, and multiple
times into a given Vulkan instance.
In all cases, each import operation must create a distinct
VkDeviceMemory object.
To export a Windows handle representing the underlying resources of a Vulkan device memory object, call:
VkResult vkGetMemoryWin32HandleKHR(
VkDevice device,
const VkMemoryGetWin32HandleInfoKHR* pGetWin32HandleInfo,
HANDLE* pHandle);
-
deviceis the logical device that created the device memory being exported. -
pGetWin32HandleInfois a pointer to an instance of the VkMemoryGetWin32HandleInfoKHR structure containing parameters of the export operation. -
pHandlewill return the Windows handle representing the underlying resources of the device memory object.
For handle types defined as NT handles, the handles returned by
vkGetMemoryWin32HandleKHR are owned by the application.
To avoid leaking resources, the application must release ownership of them
using the CloseHandle system call when they are no longer needed.
The VkMemoryGetWin32HandleInfoKHR structure is defined as:
typedef struct VkMemoryGetWin32HandleInfoKHR {
VkStructureType sType;
const void* pNext;
VkDeviceMemory memory;
VkExternalMemoryHandleTypeFlagBits handleType;
} VkMemoryGetWin32HandleInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
memoryis the memory object from which the handle will be exported. -
handleTypeis the type of handle requested.
The properties of the handle returned depend on the value of
handleType.
See VkExternalMemoryHandleTypeFlagBits for a description of the
properties of the defined external memory handle types.
Windows memory handles compatible with Vulkan may also be created by non-Vulkan APIs using methods beyond the scope of this specification. To determine the correct parameters to use when importing such handles, call:
VkResult vkGetMemoryWin32HandlePropertiesKHR(
VkDevice device,
VkExternalMemoryHandleTypeFlagBits handleType,
HANDLE handle,
VkMemoryWin32HandlePropertiesKHR* pMemoryWin32HandleProperties);
-
deviceis the logical device that will be importinghandle. -
handleTypeis the type of the handlehandle. -
handleis the handle which will be imported. -
pMemoryWin32HandlePropertieswill return properties ofhandle.
The VkMemoryWin32HandlePropertiesKHR structure returned is defined as:
typedef struct VkMemoryWin32HandlePropertiesKHR {
VkStructureType sType;
void* pNext;
uint32_t memoryTypeBits;
} VkMemoryWin32HandlePropertiesKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
memoryTypeBitsis a bitmask containing one bit set for every memory type which the specified windows handle can be imported as.
To import memory from a POSIX file descriptor handle, add a
VkImportMemoryFdInfoKHR structure to the pNext chain of the
VkMemoryAllocateInfo structure.
The VkImportMemoryFdInfoKHR structure is defined as:
typedef struct VkImportMemoryFdInfoKHR {
VkStructureType sType;
const void* pNext;
VkExternalMemoryHandleTypeFlagBits handleType;
int fd;
} VkImportMemoryFdInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
handleTypespecifies the handle type offd. -
fdis the external handle to import.
Importing memory from a file descriptor transfers ownership of the file descriptor from the application to the Vulkan implementation. The application must not perform any operations on the file descriptor after a successful import.
Applications can import the same underlying memory into multiple instances
of Vulkan, into the same instance from which it was exported, and multiple
times into a given Vulkan instance.
In all cases, each import operation must create a distinct
VkDeviceMemory object.
To export a POSIX file descriptor representing the underlying resources of a Vulkan device memory object, call:
VkResult vkGetMemoryFdKHR(
VkDevice device,
const VkMemoryGetFdInfoKHR* pGetFdInfo,
int* pFd);
-
deviceis the logical device that created the device memory being exported. -
pGetFdInfois a pointer to an instance of the VkMemoryGetFdInfoKHR structure containing parameters of the export operation. -
pFdwill return a file descriptor representing the underlying resources of the device memory object.
Each call to vkGetMemoryFdKHR must create a new file descriptor and
transfer ownership of it to the application.
To avoid leaking resources, the application must release ownership of the
file descriptor using the close system call when it is no longer
needed, or by importing a Vulkan memory object from it.
Where supported by the operating system, the implementation must set the
file descriptor to be closed automatically when an execve system call
is made.
The VkMemoryGetFdInfoKHR structure is defined as:
typedef struct VkMemoryGetFdInfoKHR {
VkStructureType sType;
const void* pNext;
VkDeviceMemory memory;
VkExternalMemoryHandleTypeFlagBits handleType;
} VkMemoryGetFdInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
memoryis the memory object from which the handle will be exported. -
handleTypeis the type of handle requested.
The properties of the file descriptor exported depend on the value of
handleType.
See VkExternalMemoryHandleTypeFlagBits for a description of the
properties of the defined external memory handle types.
|
Note
The size of the exported file may be larger than the size requested by
VkMemoryAllocateInfo::allocationSize.
If |
POSIX file descriptor memory handles compatible with Vulkan may also be created by non-Vulkan APIs using methods beyond the scope of this specification. To determine the correct parameters to use when importing such handles, call:
VkResult vkGetMemoryFdPropertiesKHR(
VkDevice device,
VkExternalMemoryHandleTypeFlagBits handleType,
int fd,
VkMemoryFdPropertiesKHR* pMemoryFdProperties);
-
deviceis the logical device that will be importingfd. -
handleTypeis the type of the handlefd. -
fdis the handle which will be imported. -
pMemoryFdPropertieswill return properties of the handlefd.
The VkMemoryFdPropertiesKHR structure returned is defined as:
typedef struct VkMemoryFdPropertiesKHR {
VkStructureType sType;
void* pNext;
uint32_t memoryTypeBits;
} VkMemoryFdPropertiesKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
memoryTypeBitsis a bitmask containing one bit set for every memory type which the specified file descriptor can be imported as.
To import memory from a host pointer, add a
VkImportMemoryHostPointerInfoEXT structure to the pNext chain of
the VkMemoryAllocateInfo structure.
The VkImportMemoryHostPointerInfoEXT structure is defined as:
typedef struct VkImportMemoryHostPointerInfoEXT {
VkStructureType sType;
const void* pNext;
VkExternalMemoryHandleTypeFlagBits handleType;
void* pHostPointer;
} VkImportMemoryHostPointerInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
handleTypespecifies the handle type. -
pHostPointeris the host pointer to import from.
Importing memory from a host pointer shares ownership of the memory between the host and the Vulkan implementation. The application can continue to access the memory through the host pointer but it is the application’s responsibility to synchronize device and non-device access to the underlying memory as defined in Host Access to Device Memory Objects.
Applications can import the same underlying memory into multiple instances of Vulkan and multiple times into a given Vulkan instance. However, implementations may fail to import the same underlying memory multiple times into a given physical device due to platform constraints.
Importing memory from a particular host pointer may not be possible due to
additional platform-specific restrictions beyond the scope of this
specification in which case the implementation must fail the memory import
operation with the error code VK_ERROR_INVALID_EXTERNAL_HANDLE_KHR.
The application must ensure that the imported memory range remains valid and accessible for the lifetime of the imported memory object.
To determine the correct parameters to use when importing host pointers, call:
VkResult vkGetMemoryHostPointerPropertiesEXT(
VkDevice device,
VkExternalMemoryHandleTypeFlagBits handleType,
const void* pHostPointer,
VkMemoryHostPointerPropertiesEXT* pMemoryHostPointerProperties);
-
deviceis the logical device that will be importingpHostPointer. -
handleTypeis the type of the handlepHostPointer. -
pHostPointeris the host pointer to import from.
The VkMemoryHostPointerPropertiesEXT structure is defined as:
typedef struct VkMemoryHostPointerPropertiesEXT {
VkStructureType sType;
void* pNext;
uint32_t memoryTypeBits;
} VkMemoryHostPointerPropertiesEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
memoryTypeBitsis a bitmask containing one bit set for every memory type which the specified host pointer can be imported as.
To import memory created outside of the current Vulkan instance from an
Android hardware buffer, add a
VkImportAndroidHardwareBufferInfoANDROID structure to the pNext
chain of the VkMemoryAllocateInfo structure.
The VkImportAndroidHardwareBufferInfoANDROID structure is defined as:
typedef struct VkImportAndroidHardwareBufferInfoANDROID {
VkStructureType sType;
const void* pNext;
struct AHardwareBuffer* buffer;
} VkImportAndroidHardwareBufferInfoANDROID;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
bufferis the Android hardware buffer to import.
If the vkAllocateMemory command succeeds, the implementation must
acquire a reference to the imported hardware buffer, which it must release
when the device memory object is freed.
If the command fails, the implementation must not retain a reference.
To export an Android hardware buffer representing the underlying resources of a Vulkan device memory object, call:
VkResult vkGetMemoryAndroidHardwareBufferANDROID(
VkDevice device,
const VkMemoryGetAndroidHardwareBufferInfoANDROID* pInfo,
struct AHardwareBuffer** pBuffer);
-
deviceis the logical device that created the device memory being exported. -
pInfois a pointer to an instance of the VkMemoryGetAndroidHardwareBufferInfoANDROID structure containing parameters of the export operation. -
pBufferwill return an Android hardware buffer representing the underlying resources of the device memory object.
Each call to vkGetMemoryAndroidHardwareBufferANDROID must return an
Android hardware buffer with a new reference acquired in addition to the
reference held by the VkDeviceMemory.
To avoid leaking resources, the application must release the reference by
calling AHardwareBuffer_release when it is no longer needed.
When called with the same handle in
VkMemoryGetAndroidHardwareBufferInfoANDROID::memory,
vkGetMemoryAndroidHardwareBufferANDROID must return the same Android
hardware buffer object.
If the device memory was created by importing an Android hardware buffer,
vkGetMemoryAndroidHardwareBufferANDROID must return that same Android
hardware buffer object.
The VkMemoryGetAndroidHardwareBufferInfoANDROID structure is defined
as:
typedef struct VkMemoryGetAndroidHardwareBufferInfoANDROID {
VkStructureType sType;
const void* pNext;
VkDeviceMemory memory;
} VkMemoryGetAndroidHardwareBufferInfoANDROID;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
memoryis the memory object from which the Android hardware buffer will be exported.
To determine the memory parameters to use when importing an Android hardware buffer, call:
VkResult vkGetAndroidHardwareBufferPropertiesANDROID(
VkDevice device,
const struct AHardwareBuffer* buffer,
VkAndroidHardwareBufferPropertiesANDROID* pProperties);
-
deviceis the logical device that will be importingbuffer. -
bufferis the Android hardware buffer which will be imported. -
pPropertieswill return properties ofbuffer.
The VkAndroidHardwareBufferPropertiesANDROID structure returned is
defined as:
typedef struct VkAndroidHardwareBufferPropertiesANDROID {
VkStructureType sType;
void* pNext;
VkDeviceSize allocationSize;
uint32_t memoryTypeBits;
} VkAndroidHardwareBufferPropertiesANDROID;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
allocationSizeis the size of the external memory -
memoryTypeBitsis a bitmask containing one bit set for every memory type which the specified Android hardware buffer can be imported as.
To obtain format properties of an Android hardware buffer, include an
instance of VkAndroidHardwareBufferFormatPropertiesANDROID in the
pNext chain of the VkAndroidHardwareBufferPropertiesANDROID
instance passed to vkGetAndroidHardwareBufferPropertiesANDROID.
This structure is defined as:
typedef struct VkAndroidHardwareBufferFormatPropertiesANDROID {
VkStructureType sType;
void* pNext;
VkFormat format;
uint64_t externalFormat;
VkFormatFeatureFlags formatFeatures;
VkComponentMapping samplerYcbcrConversionComponents;
VkSamplerYcbcrModelConversion suggestedYcbcrModel;
VkSamplerYcbcrRange suggestedYcbcrRange;
VkChromaLocation suggestedXChromaOffset;
VkChromaLocation suggestedYChromaOffset;
} VkAndroidHardwareBufferFormatPropertiesANDROID;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
formatis the Vulkan format corresponding to the Android hardware buffer’s format, orVK_FORMAT_UNDEFINEDif there isn’t an equivalent Vulkan format. -
externalFormatis an implementation-defined external format identifier for use with VkExternalFormatANDROID. It must not be zero. -
formatFeaturesdescribes the capabilities of this external format when used with an image bound to memory imported frombuffer. -
samplerYcbcrConversionComponentsis the component swizzle that should be used in VkSamplerYcbcrConversionCreateInfo. -
suggestedYcbcrModelis a suggested color model to use in the VkSamplerYcbcrConversionCreateInfo. -
suggestedYcbcrRangeis a suggested numerical value range to use in VkSamplerYcbcrConversionCreateInfo. -
suggestedXChromaOffsetis a suggested X chroma offset to use in VkSamplerYcbcrConversionCreateInfo. -
suggestedYChromaOffsetis a suggested Y chroma offset to use in VkSamplerYcbcrConversionCreateInfo.
If the Android hardware buffer has one of the formats listed in the
Format Equivalence
table, then format must have the equivalent Vulkan format listed in
the table.
Otherwise, format may be VK_FORMAT_UNDEFINED, indicating the
Android hardware buffer can only be used with an external format.
The formatFeatures member must include
VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT and at least one of
VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT or
VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT, and should include
VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT and
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BIT.
|
Note
The |
Android hardware buffers with the same external format must have the same
support for VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT,
VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT,
VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT,
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BIT,
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_SEPARATE_RECONSTRUCTION_FILTER_BIT,
and
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_FORCEABLE_BIT.
in formatFeatures.
Other format features may differ between Android hardware buffers that have
the same external format.
This allows applications to use the same VkSamplerYcbcrConversion
object (and samplers and pipelines created from them) for any Android
hardware buffers that have the same external format.
If format is not VK_FORMAT_UNDEFINED, then the value of
samplerYcbcrConversionComponents must be valid when used as the
components member of VkSamplerYcbcrConversionCreateInfo with
that format.
If format is VK_FORMAT_UNDEFINED, all members of
samplerYcbcrConversionComponents must be
VK_COMPONENT_SWIZZLE_IDENTITY.
Implementations may not always be able to determine the color model,
numerical range, or chroma offsets of the image contents, so the values in
VkAndroidHardwareBufferFormatPropertiesANDROID are only suggestions.
Applications should treat these values as sensible defaults to use in the
absence of more reliable information obtained through some other means.
If the underlying physical device is also usable via OpenGL ES with the
GL_OES_EGL_image_external extension, the implementation should suggest
values that will produce similar sampled values as would be obtained by
sampling the same external image via samplerExternalOES in OpenGL ES
using equivalent sampler parameters.
|
Note
Since GL_OES_EGL_image_external does not require the same sampling and conversion calculations as Vulkan does, achieving identical results between APIs may not be possible on some implementations. |
When allocating memory that may be exported to another process or Vulkan
instance, add a VkExportMemoryAllocateInfoNV structure to the
pNext chain of the VkMemoryAllocateInfo structure, specifying
the handle types that may be exported.
The VkExportMemoryAllocateInfoNV structure is defined as:
typedef struct VkExportMemoryAllocateInfoNV {
VkStructureType sType;
const void* pNext;
VkExternalMemoryHandleTypeFlagsNV handleTypes;
} VkExportMemoryAllocateInfoNV;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
handleTypesis a bitmask of VkExternalMemoryHandleTypeFlagBitsNV specifying one or more memory handle types that may be exported. Multiple handle types may be requested for the same allocation as long as they are compatible, as reported by vkGetPhysicalDeviceExternalImageFormatPropertiesNV.
When VkExportMemoryAllocateInfoNV::handleTypes includes
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_NV, add a
VkExportMemoryWin32HandleInfoNV to the pNext chain of the
VkExportMemoryAllocateInfoNV structure to specify security attributes
and access rights for the memory object’s external handle.
The VkExportMemoryWin32HandleInfoNV structure is defined as:
typedef struct VkExportMemoryWin32HandleInfoNV {
VkStructureType sType;
const void* pNext;
const SECURITY_ATTRIBUTES* pAttributes;
DWORD dwAccess;
} VkExportMemoryWin32HandleInfoNV;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
pAttributesis a pointer to a WindowsSECURITY_ATTRIBUTESstructure specifying security attributes of the handle. -
dwAccessis aDWORDspecifying access rights of the handle.
If this structure is not present, or if pAttributes is set to NULL,
default security descriptor values will be used, and child processes created
by the application will not inherit the handle, as described in the MSDN
documentation for “Synchronization Object Security and Access Rights”[1].
Further, if the structure is not present, the access rights will be
DXGI_SHARED_RESOURCE_READ | DXGI_SHARED_RESOURCE_WRITE
To import memory created on the same physical device but outside of the
current Vulkan instance, add a VkImportMemoryWin32HandleInfoNV
structure to the pNext chain of the VkMemoryAllocateInfo
structure, specifying a handle to and the type of the memory.
The VkImportMemoryWin32HandleInfoNV structure is defined as:
typedef struct VkImportMemoryWin32HandleInfoNV {
VkStructureType sType;
const void* pNext;
VkExternalMemoryHandleTypeFlagsNV handleType;
HANDLE handle;
} VkImportMemoryWin32HandleInfoNV;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
handleTypeis0or a VkExternalMemoryHandleTypeFlagBitsNV value specifying the type of memory handle inhandle. -
handleis a WindowsHANDLEreferring to the memory.
If handleType is 0, this structure is ignored by consumers of the
VkMemoryAllocateInfo structure it is chained from.
Bits which can be set in handleType are:
Possible values of VkImportMemoryWin32HandleInfoNV::handleType,
specifying the type of an external memory handle, are:
typedef enum VkExternalMemoryHandleTypeFlagBitsNV {
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_NV = 0x00000001,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT_NV = 0x00000002,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_IMAGE_BIT_NV = 0x00000004,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_IMAGE_KMT_BIT_NV = 0x00000008,
} VkExternalMemoryHandleTypeFlagBitsNV;
-
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT_NVspecifies a handle to memory returned by vkGetMemoryWin32HandleNV. -
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_NVspecifies a handle to memory returned by vkGetMemoryWin32HandleNV, or one duplicated from such a handle usingDuplicateHandle(). -
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_IMAGE_BIT_NVspecifies a valid NT handle to memory returned byIDXGIResource1::, or a handle duplicated from such a handle usingCreateSharedHandle()DuplicateHandle(). -
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_IMAGE_KMT_BIT_NVspecifies a handle to memory returned byIDXGIResource::GetSharedHandle().
|
editing-note
(Jon) If additional (non-Win32) bits are added to the possible memory types,
this type should move to the |
typedef VkFlags VkExternalMemoryHandleTypeFlagsNV;
VkExternalMemoryHandleTypeFlagsNV is a bitmask type for setting a mask
of zero or more VkExternalMemoryHandleTypeFlagBitsNV.
To retrieve the handle corresponding to a device memory object created with
VkExportMemoryAllocateInfoNV::handleTypes set to include
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_NV or
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT_NV, call:
VkResult vkGetMemoryWin32HandleNV(
VkDevice device,
VkDeviceMemory memory,
VkExternalMemoryHandleTypeFlagsNV handleType,
HANDLE* pHandle);
-
deviceis the logical device that owns the memory. -
memoryis theVkDeviceMemoryobject. -
handleTypeis a bitmask of VkExternalMemoryHandleTypeFlagBitsNV containing a single bit specifying the type of handle requested. -
handlepoints to a WindowsHANDLEin which the handle is returned.
If the pNext chain of VkMemoryAllocateInfo includes a
VkMemoryAllocateFlagsInfo structure, then that structure includes
flags and a device mask controlling how many instances of the memory will be
allocated.
The VkMemoryAllocateFlagsInfo structure is defined as:
typedef struct VkMemoryAllocateFlagsInfo {
VkStructureType sType;
const void* pNext;
VkMemoryAllocateFlags flags;
uint32_t deviceMask;
} VkMemoryAllocateFlagsInfo;
or the equivalent
typedef VkMemoryAllocateFlagsInfo VkMemoryAllocateFlagsInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis a bitmask of VkMemoryAllocateFlagBits controlling the allocation. -
deviceMaskis a mask of physical devices in the logical device, indicating that memory must be allocated on each device in the mask, ifVK_MEMORY_ALLOCATE_DEVICE_MASK_BITis set inflags.
If VK_MEMORY_ALLOCATE_DEVICE_MASK_BIT is not set, the number of
instances allocated depends on whether
VK_MEMORY_HEAP_MULTI_INSTANCE_BIT is set in the memory heap.
If VK_MEMORY_HEAP_MULTI_INSTANCE_BIT is set, then memory is allocated
for every physical device in the logical device (as if deviceMask has
bits set for all device indices).
If VK_MEMORY_HEAP_MULTI_INSTANCE_BIT is not set, then a single
instance of memory is allocated (as if deviceMask is set to one).
On some implementations, allocations from a multi-instance heap may consume
memory on all physical devices even if the deviceMask excludes some
devices.
If VkPhysicalDeviceGroupProperties::subsetAllocation is
VK_TRUE, then memory is only consumed for the devices in the device
mask.
|
Note
In practice, most allocations on a multi-instance heap will be allocated across all physical devices. Unicast allocation support is an optional optimization for a minority of allocations. |
Bits which can be set in VkMemoryAllocateFlagsInfo::flags,
controlling device memory allocation, are:
typedef enum VkMemoryAllocateFlagBits {
VK_MEMORY_ALLOCATE_DEVICE_MASK_BIT = 0x00000001,
VK_MEMORY_ALLOCATE_DEVICE_MASK_BIT_KHR = VK_MEMORY_ALLOCATE_DEVICE_MASK_BIT,
} VkMemoryAllocateFlagBits;
or the equivalent
typedef VkMemoryAllocateFlagBits VkMemoryAllocateFlagBitsKHR;
-
VK_MEMORY_ALLOCATE_DEVICE_MASK_BITspecifies that memory will be allocated for the devices in VkMemoryAllocateFlagsInfo::deviceMask.
typedef VkFlags VkMemoryAllocateFlags;
or the equivalent
typedef VkMemoryAllocateFlags VkMemoryAllocateFlagsKHR;
VkMemoryAllocateFlags is a bitmask type for setting a mask of zero or
more VkMemoryAllocateFlagBits.
To free a memory object, call:
void vkFreeMemory(
VkDevice device,
VkDeviceMemory memory,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that owns the memory. -
memoryis theVkDeviceMemoryobject to be freed. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
Before freeing a memory object, an application must ensure the memory object is no longer in use by the device—for example by command buffers in the pending state. The memory can remain bound to images or buffers at the time the memory object is freed, but any further use of them (on host or device) for anything other than destroying those objects will result in undefined behavior. If there are still any bound images or buffers, the memory may not be immediately released by the implementation, but must be released by the time all bound images and buffers have been destroyed. Once memory is released, it is returned to the heap from which it was allocated.
How memory objects are bound to Images and Buffers is described in detail in the Resource Memory Association section.
If a memory object is mapped at the time it is freed, it is implicitly unmapped.
|
Note
As described below, host writes are not implicitly flushed when the memory object is unmapped, but the implementation must guarantee that writes that have not been flushed do not affect any other memory. |
10.2.1. Host Access to Device Memory Objects
Memory objects created with vkAllocateMemory are not directly host accessible.
Memory objects created with the memory property
VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT are considered mappable.
Memory objects must be mappable in order to be successfully mapped on the
host.
To retrieve a host virtual address pointer to a region of a mappable memory object, call:
VkResult vkMapMemory(
VkDevice device,
VkDeviceMemory memory,
VkDeviceSize offset,
VkDeviceSize size,
VkMemoryMapFlags flags,
void** ppData);
-
deviceis the logical device that owns the memory. -
memoryis theVkDeviceMemoryobject to be mapped. -
offsetis a zero-based byte offset from the beginning of the memory object. -
sizeis the size of the memory range to map, orVK_WHOLE_SIZEto map fromoffsetto the end of the allocation. -
flagsis reserved for future use. -
ppDatapoints to a pointer in which is returned a host-accessible pointer to the beginning of the mapped range. This pointer minusoffsetmust be aligned to at least VkPhysicalDeviceLimits::minMemoryMapAlignment.
It is an application error to call vkMapMemory on a memory object that
is already mapped.
|
Note
|
vkMapMemory does not check whether the device memory is currently in
use before returning the host-accessible pointer.
The application must guarantee that any previously submitted command that
writes to this range has completed before the host reads from or writes to
that range, and that any previously submitted command that reads from that
range has completed before the host writes to that region (see
here for details on fulfilling
such a guarantee).
If the device memory was allocated without the
VK_MEMORY_PROPERTY_HOST_COHERENT_BIT set, these guarantees must be
made for an extended range: the application must round down the start of
the range to the nearest multiple of
VkPhysicalDeviceLimits::nonCoherentAtomSize, and round the end
of the range up to the nearest multiple of
VkPhysicalDeviceLimits::nonCoherentAtomSize.
While a range of device memory is mapped for host access, the application is responsible for synchronizing both device and host access to that memory range.
|
Note
It is important for the application developer to become meticulously familiar with all of the mechanisms described in the chapter on Synchronization and Cache Control as they are crucial to maintaining memory access ordering. |
typedef VkFlags VkMemoryMapFlags;
VkMemoryMapFlags is a bitmask type for setting a mask, but is
currently reserved for future use.
Two commands are provided to enable applications to work with non-coherent
memory allocations: vkFlushMappedMemoryRanges and
vkInvalidateMappedMemoryRanges.
|
Note
If the memory object was created with the
|
To flush ranges of non-coherent memory from the host caches, call:
VkResult vkFlushMappedMemoryRanges(
VkDevice device,
uint32_t memoryRangeCount,
const VkMappedMemoryRange* pMemoryRanges);
-
deviceis the logical device that owns the memory ranges. -
memoryRangeCountis the length of thepMemoryRangesarray. -
pMemoryRangesis a pointer to an array of VkMappedMemoryRange structures describing the memory ranges to flush.
vkFlushMappedMemoryRanges guarantees that host writes to the memory
ranges described by pMemoryRanges can be made available to device
access, via availability operations from the VK_ACCESS_HOST_WRITE_BIT
access type.
Within each range described by pMemoryRanges, each set of
nonCoherentAtomSize bytes in that range is flushed if any byte in that
set has been written by the host since it was first mapped, or the last time
it was flushed.
If pMemoryRanges includes sets of nonCoherentAtomSize bytes
where no bytes have been written by the host, those bytes must not be
flushed.
Unmapping non-coherent memory does not implicitly flush the mapped memory, and host writes that have not been flushed may not ever be visible to the device. However, implementations must ensure that writes that have not been flushed do not become visible to any other memory.
|
Note
The above guarantee avoids a potential memory corruption in scenarios where host writes to a mapped memory object have not been flushed before the memory is unmapped (or freed), and the virtual address range is subsequently reused for a different mapping (or memory allocation). |
To invalidate ranges of non-coherent memory from the host caches, call:
VkResult vkInvalidateMappedMemoryRanges(
VkDevice device,
uint32_t memoryRangeCount,
const VkMappedMemoryRange* pMemoryRanges);
-
deviceis the logical device that owns the memory ranges. -
memoryRangeCountis the length of thepMemoryRangesarray. -
pMemoryRangesis a pointer to an array of VkMappedMemoryRange structures describing the memory ranges to invalidate.
vkInvalidateMappedMemoryRanges guarantees that device writes to the
memory ranges described by pMemoryRanges, which have been made visible
to the VK_ACCESS_HOST_WRITE_BIT and VK_ACCESS_HOST_READ_BIT
access types, are made visible to the
host.
If a range of non-coherent memory is written by the host and then
invalidated without first being flushed, its contents are undefined.
Within each range described by pMemoryRanges, each set of
nonCoherentAtomSize bytes in that range is invalidated if any byte in
that set has been written by the device since it was first mapped, or the
last time it was invalidated.
|
Note
Mapping non-coherent memory does not implicitly invalidate the mapped memory, and device writes that have not been invalidated must be made visible before the host reads or overwrites them. |
The VkMappedMemoryRange structure is defined as:
typedef struct VkMappedMemoryRange {
VkStructureType sType;
const void* pNext;
VkDeviceMemory memory;
VkDeviceSize offset;
VkDeviceSize size;
} VkMappedMemoryRange;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
memoryis the memory object to which this range belongs. -
offsetis the zero-based byte offset from the beginning of the memory object. -
sizeis either the size of range, orVK_WHOLE_SIZEto affect the range fromoffsetto the end of the current mapping of the allocation.
To unmap a memory object once host access to it is no longer needed by the application, call:
void vkUnmapMemory(
VkDevice device,
VkDeviceMemory memory);
-
deviceis the logical device that owns the memory. -
memoryis the memory object to be unmapped.
10.2.2. Lazily Allocated Memory
If the memory object is allocated from a heap with the
VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT bit set, that object’s backing
memory may be provided by the implementation lazily.
The actual committed size of the memory may initially be as small as zero
(or as large as the requested size), and monotonically increases as
additional memory is needed.
A memory type with this flag set is only allowed to be bound to a
VkImage whose usage flags include
VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT.
|
Note
Using lazily allocated memory objects for framebuffer attachments that are not needed once a render pass instance has completed may allow some implementations to never allocate memory for such attachments. |
To determine the amount of lazily-allocated memory that is currently committed for a memory object, call:
void vkGetDeviceMemoryCommitment(
VkDevice device,
VkDeviceMemory memory,
VkDeviceSize* pCommittedMemoryInBytes);
-
deviceis the logical device that owns the memory. -
memoryis the memory object being queried. -
pCommittedMemoryInBytesis a pointer to aVkDeviceSizevalue in which the number of bytes currently committed is returned, on success.
The implementation may update the commitment at any time, and the value returned by this query may be out of date.
The implementation guarantees to allocate any committed memory from the heapIndex indicated by the memory type that the memory object was created with.
10.2.3. Protected Memory
Protected memory divides device memory into protected device memory and unprotected device memory.
Protected memory adds the following concepts:
-
Memory:
-
Unprotected device memory, which can be visible to the device and can be visible to the host
-
Protected device memory, which can be visible to the device but must not be visible to the host
-
-
Resources:
-
Unprotected images and unprotected buffers, to which unprotected memory can be bound
-
Protected images and protected buffers, to which protected memory can be bound
-
-
Command buffers:
-
Unprotected command buffers, which can be submitted to a device queue to execute unprotected queue operations
-
Protected command buffers, which can be submitted to a protected-capable device queue to execute protected queue operations
-
-
Device queues:
-
Unprotected device queues, to which unprotected command buffers can be submitted
-
Protected-capable device queues, to which unprotected command buffers or protected command buffers can be submitted
-
-
Queue submissions
-
Unprotected queue submissions, through which unprotected command buffers can be submitted
-
Protected queue submissions, through which protected command buffers can be submitted
-
-
Queue operations
-
Unprotected queue operations
-
Any read from or write to protected memory during unprotected queue operations results in undefined behavior but is subject to the inviolable rules below.
-
-
Protected queue operations
-
Any write to unprotected memory during protected queue operations results in undefined behavior but is subject to the inviolable rules below.
-
Except for framebuffer-space pipeline stages, compute shader stage, and transfer stage, any read from or write to protected memory during protected queue operations results in undefined behavior but is subject to the inviolable rules below.
-
Any queries during protected queue operations results in undefined behavior but is subject to the inviolable rules below.
-
-
Protected memory inviolable rules
Implementations must ensure that correct usage or incorrect usage by an application does not affect the integrity of the memory protection system.
The implementation must guarantee that:
-
Protected device memory must not be visible to the host.
-
Values written to unprotected device memory must not be a function of data from protected memory.
Incorrect usage by an application of the memory protection system results in undefined behavior which may include process termination or device loss.
10.2.4. External Memory Handle Types
Android Hardware Buffer
Android’s NDK defines AHardwareBuffer objects which represent device
memory that is shareable across processes and that can be accessed by a
variety of media APIs and the hardware used to implement them.
These Android hardware buffer objects may be imported into
VkDeviceMemory objects for access via Vulkan, or exported from Vulkan.
Android hardware buffer objects are reference-counted using Android NDK
functions outside the scope of this specification.
A VkDeviceMemory imported from an Android hardware buffer or that can
be exported to an Android hardware buffer must acquire a reference to its
AHardwareBuffer object, and must release this reference when the
device memory is freed.
During the host execution of a Vulkan command which has an Android hardware
buffer as a parameter (including indirect parameters via pNext
chains), the application must not decrement the Android hardware buffer’s
reference count to zero.
Android hardware buffers can be mapped and unmapped for CPU access using NDK functions. These lock and unlock APIs are considered to acquire and release ownership of the Android hardware buffer, and applications must follow the rules described in External Resource Sharing to transfer ownership between the Vulkan instance and these native APIs.
Android hardware buffers can be shared with external APIs and Vulkan instances on the same device and also with foreign devices. When transferring ownership of the Android hardware buffer, the external and foreign special queue families described in Queue Family Ownership Transfer are not identical. All APIs which produce or consume Android hardware buffers are considered to use foreign devices, except OpenGL ES contexts and Vulkan logical devices that have matching device and driver UUIDs. Implementations may treat a transfer to or from the foreign queue family as if it were a transfer to or from the external queue family when the Android hardware buffer’s usage only permits it to be used on the same physical device.
Android Hardware Buffer Optimal Usages
Vulkan buffer and image usage flags do not correspond exactly to Android hardware buffer usage flags. When allocating Android hardware buffers with non-Vulkan APIs, if any AHARDWAREBUFFER_USAGE_GPU_* usage bits are included, by default the allocator must allocate the memory in such a way that it can support Vulkan usages and creation flags in the usage equivalence table which don’t have Android hardware buffer equivalents.
The VkAndroidHardwareBufferUsageANDROID structure can be attached to
the pNext chain of a VkImageFormatProperties2 instance passed to
vkGetPhysicalDeviceImageFormatProperties2 to obtain optimal Android
hardware buffer usage flags for specific Vulkan resource creation
parameters.
Some usage flags returned by these commands are required based on the input
parameters, but additional vendor-specific usage flags
(AHARDWAREBUFFER_USAGE_VENDOR_*) may also be returned.
Any Android hardware buffer allocated with these vendor-specific usage flags
and imported to Vulkan must only be bound to resources created with
parameters that are a subset of the parameters used to obtain the Android
hardware buffer usage, since the memory may have been allocated in a way
incompatible with other parameters.
If a Android hardware buffer is successfully allocated with additional
non-vendor-specific usage flags in addition to the recommended usage, it
must support being used in the same ways as a Android hardware buffer
allocated with only the recommended usage, and also in ways indicated by the
additional usage.
Android Hardware Buffer External Formats
Android hardware buffers can represent images using implementation-specific formats, layouts, color models, etc. which don’t have Vulkan equivalents. Such external formats are commonly used by external image sources such as video decoders or cameras. Vulkan can import Android hardware buffers that have external formats, but since the image contents are in an undiscoverable and possibly proprietary representation, images with external formats must only be used as sampled images, must only be sampled with a sampler that has Y’CBCR conversion enabled, and must have optimal tiling.
Images that will be backed by a Android hardware buffer can use an external
format by setting VkImageCreateInfo::format to
VK_FORMAT_UNDEFINED and including an instance of
VkExternalFormatANDROID in the pNext chain.
Images can be created with an external format even if the Android hardware
buffer has a format which has an
equivalent Vulkan format
to enable consistent handling of images from sources that might use either
category of format.
However, all images created with an external format are subject to the valid
usage requirements associated with external formats, even if the Android
hardware buffer’s format has a Vulkan equivalent.
The external format of an Android hardware buffer can be obtained by
passing an instance of VkAndroidHardwareBufferFormatPropertiesANDROID
to vkGetAndroidHardwareBufferPropertiesANDROID.
Android Hardware Buffer Image Resources
Android hardware buffers have intrinsic width, height, format, and usage
properties, so Vulkan images bound to memory imported from an Android
hardware buffer must use dedicated allocations:
VkMemoryDedicatedRequirements::requiresDedicatedAllocation must
be VK_TRUE for images created with
VkExternalMemoryImageCreateInfo::handleTypes that includes
VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID.
When creating an image that will be bound to an imported Android hardware
buffer, the image creation parameters must be equivalent to the
AHardwareBuffer properties as described by the valid usage of
VkMemoryAllocateInfo.
Similarly, device memory allocated for a dedicated image must not be
exported to an Android hardware buffer until it has been bound to that
image, and the implementation must return an Android hardware buffer with
properties derived from the image:
-
The
widthandheightmembers ofAHardwareBuffer_descmust be the same as thewidthandheightmembers ofVkImageCreateInfo::extent, respectively; -
The
layersmember ofAHardwareBuffer_descmust be the same as thearrayLayersmember ofVkImageCreateInfo; -
The
formatmember ofAHardwareBuffer_descmust be equivalent toVkImageCreateInfo::formatas defined by AHardwareBuffer Format Equivalence; -
The
usagemember ofAHardwareBuffer_descmust include bits corresponding to bits included inVkImageCreateInfo::usageandVkImageCreateInfo::flagswhere such a correspondence exists according to AHardwareBuffer Usage Equivalence. It may also include additional usage bits, including vendor-specific usages. Presence of vendor usage bits may make the Android hardware buffer only usable in ways indicated by the image creation parameters, even when used outside Vulkan, in a similar way that allocating the Android hardware buffer with usage returned in VkAndroidHardwareBufferUsageANDROID.
Implementations may support fewer combinations of image creation parameters
for images with Android hardware buffer external handle type than for
non-external images.
Support for a given set of parameters can be determined by passing
VkExternalImageFormatProperties to
vkGetPhysicalDeviceImageFormatProperties2 with handleType set to
VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID.
Any Android hardware buffer successfully allocated outside Vulkan with usage
that includes AHARDWAREBUFFER_USAGE_GPU_* must be supported when using
equivalent Vulkan image parameters.
If a given choice of image parameters are supported for import, they can
also be used to create an image and memory that will be exported to an
Android hardware buffer.
| AHardwareBuffer Format | Vulkan Format |
|---|---|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| AHardwareBuffer Usage | Vulkan Usage or Creation Flag |
|---|---|
None |
|
None |
|
|
|
|
|
|
|
|
|
|
None 2 |
|
|
None |
|
None |
|
- 2
-
The
AHARDWAREBUFFER_USAGE_GPU_MIPMAP_COMPLETEflag does not correspond to a Vulkan image usage or creation flag. Instead, it’s presence indicates that the Android hardware buffer contains a complete set of mip levels (VkImageCreateInfo::mipLevelsis ⌈log2(max(width,height))⌉ + 1), and it’s absence indicates that the Android hardware buffer contains only a single mip level.
|
Note
When using |
Android Hardware Buffer Buffer Resources
Android hardware buffers with a format of AHARDWAREBUFFER_FORMAT_BLOB
and usage that includes AHARDWAREBUFFER_USAGE_GPU_DATA_BUFFER may be
used as the backing store for VkBuffer objects.
Such Android hardware buffers have a size in bytes specified by their
width; height and layers are 1.
Unlike images, buffer resources backed by Android hardware buffers do not require dedicated allocations.
Exported AHardwareBuffer objects that do not have dedicated images
must have a format of AHARDWAREBUFFER_FORMAT_BLOB, usage must include
AHARDWAREBUFFER_USAGE_GPU_DATA_BUFFER, width must equal the
device memory allocation size, and height and layers must be
1.
10.2.5. Peer Memory Features
Peer memory is memory that is allocated for a given physical device and then bound to a resource and accessed by a different physical device, in a logical device that represents multiple physical devices. Some ways of reading and writing peer memory may not be supported by a device.
To determine how peer memory can be accessed, call:
void vkGetDeviceGroupPeerMemoryFeatures(
VkDevice device,
uint32_t heapIndex,
uint32_t localDeviceIndex,
uint32_t remoteDeviceIndex,
VkPeerMemoryFeatureFlags* pPeerMemoryFeatures);
or the equivalent command
void vkGetDeviceGroupPeerMemoryFeaturesKHR(
VkDevice device,
uint32_t heapIndex,
uint32_t localDeviceIndex,
uint32_t remoteDeviceIndex,
VkPeerMemoryFeatureFlags* pPeerMemoryFeatures);
-
deviceis the logical device that owns the memory. -
heapIndexis the index of the memory heap from which the memory is allocated. -
localDeviceIndexis the device index of the physical device that performs the memory access. -
remoteDeviceIndexis the device index of the physical device that the memory is allocated for. -
pPeerMemoryFeaturesis a pointer to a bitmask of VkPeerMemoryFeatureFlagBits indicating which types of memory accesses are supported for the combination of heap, local, and remote devices.
Bits which may be set in the value returned for
vkGetDeviceGroupPeerMemoryFeatures::pPeerMemoryFeatures,
indicating the supported peer memory features, are:
typedef enum VkPeerMemoryFeatureFlagBits {
VK_PEER_MEMORY_FEATURE_COPY_SRC_BIT = 0x00000001,
VK_PEER_MEMORY_FEATURE_COPY_DST_BIT = 0x00000002,
VK_PEER_MEMORY_FEATURE_GENERIC_SRC_BIT = 0x00000004,
VK_PEER_MEMORY_FEATURE_GENERIC_DST_BIT = 0x00000008,
VK_PEER_MEMORY_FEATURE_COPY_SRC_BIT_KHR = VK_PEER_MEMORY_FEATURE_COPY_SRC_BIT,
VK_PEER_MEMORY_FEATURE_COPY_DST_BIT_KHR = VK_PEER_MEMORY_FEATURE_COPY_DST_BIT,
VK_PEER_MEMORY_FEATURE_GENERIC_SRC_BIT_KHR = VK_PEER_MEMORY_FEATURE_GENERIC_SRC_BIT,
VK_PEER_MEMORY_FEATURE_GENERIC_DST_BIT_KHR = VK_PEER_MEMORY_FEATURE_GENERIC_DST_BIT,
} VkPeerMemoryFeatureFlagBits;
or the equivalent
typedef VkPeerMemoryFeatureFlagBits VkPeerMemoryFeatureFlagBitsKHR;
-
VK_PEER_MEMORY_FEATURE_COPY_SRC_BITspecifies that the memory can be accessed as the source of avkCmdCopyBuffer,vkCmdCopyImage,vkCmdCopyBufferToImage, orvkCmdCopyImageToBuffercommand. -
VK_PEER_MEMORY_FEATURE_COPY_DST_BITspecifies that the memory can be accessed as the destination of avkCmdCopyBuffer,vkCmdCopyImage,vkCmdCopyBufferToImage, orvkCmdCopyImageToBuffercommand. -
VK_PEER_MEMORY_FEATURE_GENERIC_SRC_BITspecifies that the memory can be read as any memory access type. -
VK_PEER_MEMORY_FEATURE_GENERIC_DST_BITspecifies that the memory can be written as any memory access type. Shader atomics are considered to be writes.
|
Note
The peer memory features of a memory heap also apply to any accesses that may be performed during image layout transitions. |
VK_PEER_MEMORY_FEATURE_COPY_DST_BIT must be supported for all host
local heaps and for at least one device local heap.
If a device does not support a peer memory feature, it is still valid to use a resource that includes both local and peer memory bindings with the corresponding access type as long as only the local bindings are actually accessed. For example, an application doing split-frame rendering would use framebuffer attachments that include both local and peer memory bindings, but would scissor the rendering to only update local memory.
typedef VkFlags VkPeerMemoryFeatureFlags;
or the equivalent
typedef VkPeerMemoryFeatureFlags VkPeerMemoryFeatureFlagsKHR;
VkPeerMemoryFeatureFlags is a bitmask type for setting a mask of zero
or more VkPeerMemoryFeatureFlagBits.
11. Resource Creation
Vulkan supports two primary resource types: buffers and images. Resources are views of memory with associated formatting and dimensionality. Buffers are essentially unformatted arrays of bytes whereas images contain format information, can be multidimensional and may have associated metadata.
11.1. Buffers
Buffers represent linear arrays of data which are used for various purposes by binding them to a graphics or compute pipeline via descriptor sets or via certain commands, or by directly specifying them as parameters to certain commands.
Buffers are represented by VkBuffer handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkBuffer)
To create buffers, call:
VkResult vkCreateBuffer(
VkDevice device,
const VkBufferCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkBuffer* pBuffer);
-
deviceis the logical device that creates the buffer object. -
pCreateInfois a pointer to an instance of theVkBufferCreateInfostructure containing parameters affecting creation of the buffer. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pBufferpoints to aVkBufferhandle in which the resulting buffer object is returned.
The VkBufferCreateInfo structure is defined as:
typedef struct VkBufferCreateInfo {
VkStructureType sType;
const void* pNext;
VkBufferCreateFlags flags;
VkDeviceSize size;
VkBufferUsageFlags usage;
VkSharingMode sharingMode;
uint32_t queueFamilyIndexCount;
const uint32_t* pQueueFamilyIndices;
} VkBufferCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis a bitmask of VkBufferCreateFlagBits specifying additional parameters of the buffer. -
sizeis the size in bytes of the buffer to be created. -
usageis a bitmask of VkBufferUsageFlagBits specifying allowed usages of the buffer. -
sharingModeis a VkSharingMode value specifying the sharing mode of the buffer when it will be accessed by multiple queue families. -
queueFamilyIndexCountis the number of entries in thepQueueFamilyIndicesarray. -
pQueueFamilyIndicesis a list of queue families that will access this buffer (ignored ifsharingModeis notVK_SHARING_MODE_CONCURRENT).
|
editing-note
(Jon) Should the constraint on usage != 0 be converted to a Valid Usage statement? See gitlab #854. |
Bits which can be set in VkBufferCreateInfo::usage, specifying
usage behavior of a buffer, are:
typedef enum VkBufferUsageFlagBits {
VK_BUFFER_USAGE_TRANSFER_SRC_BIT = 0x00000001,
VK_BUFFER_USAGE_TRANSFER_DST_BIT = 0x00000002,
VK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BIT = 0x00000004,
VK_BUFFER_USAGE_STORAGE_TEXEL_BUFFER_BIT = 0x00000008,
VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT = 0x00000010,
VK_BUFFER_USAGE_STORAGE_BUFFER_BIT = 0x00000020,
VK_BUFFER_USAGE_INDEX_BUFFER_BIT = 0x00000040,
VK_BUFFER_USAGE_VERTEX_BUFFER_BIT = 0x00000080,
VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT = 0x00000100,
} VkBufferUsageFlagBits;
-
VK_BUFFER_USAGE_TRANSFER_SRC_BITspecifies that the buffer can be used as the source of a transfer command (see the definition ofVK_PIPELINE_STAGE_TRANSFER_BIT). -
VK_BUFFER_USAGE_TRANSFER_DST_BITspecifies that the buffer can be used as the destination of a transfer command. -
VK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BITspecifies that the buffer can be used to create aVkBufferViewsuitable for occupying aVkDescriptorSetslot of typeVK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER. -
VK_BUFFER_USAGE_STORAGE_TEXEL_BUFFER_BITspecifies that the buffer can be used to create aVkBufferViewsuitable for occupying aVkDescriptorSetslot of typeVK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER. -
VK_BUFFER_USAGE_UNIFORM_BUFFER_BITspecifies that the buffer can be used in aVkDescriptorBufferInfosuitable for occupying aVkDescriptorSetslot either of typeVK_DESCRIPTOR_TYPE_UNIFORM_BUFFERorVK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC. -
VK_BUFFER_USAGE_STORAGE_BUFFER_BITspecifies that the buffer can be used in aVkDescriptorBufferInfosuitable for occupying aVkDescriptorSetslot either of typeVK_DESCRIPTOR_TYPE_STORAGE_BUFFERorVK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC. -
VK_BUFFER_USAGE_INDEX_BUFFER_BITspecifies that the buffer is suitable for passing as thebufferparameter tovkCmdBindIndexBuffer. -
VK_BUFFER_USAGE_VERTEX_BUFFER_BITspecifies that the buffer is suitable for passing as an element of thepBuffersarray tovkCmdBindVertexBuffers. -
VK_BUFFER_USAGE_INDIRECT_BUFFER_BITspecifies that the buffer is suitable for passing as thebufferparameter tovkCmdDrawIndirect,vkCmdDrawIndexedIndirect, orvkCmdDispatchIndirect. It is also suitable for passing as thebuffermember ofVkIndirectCommandsTokenNVX, orsequencesCountBufferorsequencesIndexBuffermember ofVkCmdProcessCommandsInfoNVX
typedef VkFlags VkBufferUsageFlags;
VkBufferUsageFlags is a bitmask type for setting a mask of zero or
more VkBufferUsageFlagBits.
Bits which can be set in VkBufferCreateInfo::flags, specifying
additional parameters of a buffer, are:
typedef enum VkBufferCreateFlagBits {
VK_BUFFER_CREATE_SPARSE_BINDING_BIT = 0x00000001,
VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT = 0x00000002,
VK_BUFFER_CREATE_SPARSE_ALIASED_BIT = 0x00000004,
VK_BUFFER_CREATE_PROTECTED_BIT = 0x00000008,
} VkBufferCreateFlagBits;
-
VK_BUFFER_CREATE_SPARSE_BINDING_BITspecifies that the buffer will be backed using sparse memory binding. -
VK_BUFFER_CREATE_SPARSE_RESIDENCY_BITspecifies that the buffer can be partially backed using sparse memory binding. Buffers created with this flag must also be created with theVK_BUFFER_CREATE_SPARSE_BINDING_BITflag. -
VK_BUFFER_CREATE_SPARSE_ALIASED_BITspecifies that the buffer will be backed using sparse memory binding with memory ranges that might also simultaneously be backing another buffer (or another portion of the same buffer). Buffers created with this flag must also be created with theVK_BUFFER_CREATE_SPARSE_BINDING_BITflag. -
VK_BUFFER_CREATE_PROTECTED_BITspecifies that the buffer is a protected buffer.
See Sparse Resource Features and Physical Device Features for details of the sparse memory features supported on a device.
typedef VkFlags VkBufferCreateFlags;
VkBufferCreateFlags is a bitmask type for setting a mask of zero or
more VkBufferCreateFlagBits.
If the pNext chain includes a
VkDedicatedAllocationBufferCreateInfoNV structure, then that structure
includes an enable controlling whether the buffer will have a dedicated
memory allocation bound to it.
The VkDedicatedAllocationBufferCreateInfoNV structure is defined as:
typedef struct VkDedicatedAllocationBufferCreateInfoNV {
VkStructureType sType;
const void* pNext;
VkBool32 dedicatedAllocation;
} VkDedicatedAllocationBufferCreateInfoNV;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
dedicatedAllocationspecifies whether the buffer will have a dedicated allocation bound to it.
To define a set of external memory handle types that may be used as backing
store for a buffer, add a VkExternalMemoryBufferCreateInfo structure
to the pNext chain of the VkBufferCreateInfo structure.
The VkExternalMemoryBufferCreateInfo structure is defined as:
typedef struct VkExternalMemoryBufferCreateInfo {
VkStructureType sType;
const void* pNext;
VkExternalMemoryHandleTypeFlags handleTypes;
} VkExternalMemoryBufferCreateInfo;
or the equivalent
typedef VkExternalMemoryBufferCreateInfo VkExternalMemoryBufferCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
handleTypesis a bitmask of VkExternalMemoryHandleTypeFlagBits specifying one or more external memory handle types.
To destroy a buffer, call:
void vkDestroyBuffer(
VkDevice device,
VkBuffer buffer,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the buffer. -
bufferis the buffer to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
11.2. Buffer Views
A buffer view represents a contiguous range of a buffer and a specific format to be used to interpret the data. Buffer views are used to enable shaders to access buffer contents interpreted as formatted data. In order to create a valid buffer view, the buffer must have been created with at least one of the following usage flags:
-
VK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BIT -
VK_BUFFER_USAGE_STORAGE_TEXEL_BUFFER_BIT
Buffer views are represented by VkBufferView handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkBufferView)
To create a buffer view, call:
VkResult vkCreateBufferView(
VkDevice device,
const VkBufferViewCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkBufferView* pView);
-
deviceis the logical device that creates the buffer view. -
pCreateInfois a pointer to an instance of theVkBufferViewCreateInfostructure containing parameters to be used to create the buffer. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pViewpoints to aVkBufferViewhandle in which the resulting buffer view object is returned.
The VkBufferViewCreateInfo structure is defined as:
typedef struct VkBufferViewCreateInfo {
VkStructureType sType;
const void* pNext;
VkBufferViewCreateFlags flags;
VkBuffer buffer;
VkFormat format;
VkDeviceSize offset;
VkDeviceSize range;
} VkBufferViewCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
bufferis aVkBufferon which the view will be created. -
formatis a VkFormat describing the format of the data elements in the buffer. -
offsetis an offset in bytes from the base address of the buffer. Accesses to the buffer view from shaders use addressing that is relative to this starting offset. -
rangeis a size in bytes of the buffer view. Ifrangeis equal toVK_WHOLE_SIZE, the range fromoffsetto the end of the buffer is used. IfVK_WHOLE_SIZEis used and the remaining size of the buffer is not a multiple of the element size offormat, then the nearest smaller multiple is used.
typedef VkFlags VkBufferViewCreateFlags;
VkBufferViewCreateFlags is a bitmask type for setting a mask, but is
currently reserved for future use.
To destroy a buffer view, call:
void vkDestroyBufferView(
VkDevice device,
VkBufferView bufferView,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the buffer view. -
bufferViewis the buffer view to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
11.3. Images
Images represent multidimensional - up to 3 - arrays of data which can be used for various purposes (e.g. attachments, textures), by binding them to a graphics or compute pipeline via descriptor sets, or by directly specifying them as parameters to certain commands.
Images are represented by VkImage handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkImage)
To create images, call:
VkResult vkCreateImage(
VkDevice device,
const VkImageCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkImage* pImage);
-
deviceis the logical device that creates the image. -
pCreateInfois a pointer to an instance of theVkImageCreateInfostructure containing parameters to be used to create the image. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pImagepoints to aVkImagehandle in which the resulting image object is returned.
The VkImageCreateInfo structure is defined as:
typedef struct VkImageCreateInfo {
VkStructureType sType;
const void* pNext;
VkImageCreateFlags flags;
VkImageType imageType;
VkFormat format;
VkExtent3D extent;
uint32_t mipLevels;
uint32_t arrayLayers;
VkSampleCountFlagBits samples;
VkImageTiling tiling;
VkImageUsageFlags usage;
VkSharingMode sharingMode;
uint32_t queueFamilyIndexCount;
const uint32_t* pQueueFamilyIndices;
VkImageLayout initialLayout;
} VkImageCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis a bitmask of VkImageCreateFlagBits describing additional parameters of the image. -
imageTypeis a VkImageType value specifying the basic dimensionality of the image. Layers in array textures do not count as a dimension for the purposes of the image type. -
formatis a VkFormat describing the format and type of the data elements that will be contained in the image. -
extentis a VkExtent3D describing the number of data elements in each dimension of the base level. -
mipLevelsdescribes the number of levels of detail available for minified sampling of the image. -
arrayLayersis the number of layers in the image. -
samplesis the number of sub-data element samples in the image as defined in VkSampleCountFlagBits. See Multisampling. -
tilingis a VkImageTiling value specifying the tiling arrangement of the data elements in memory. -
usageis a bitmask of VkImageUsageFlagBits describing the intended usage of the image. -
sharingModeis a VkSharingMode value specifying the sharing mode of the image when it will be accessed by multiple queue families. -
queueFamilyIndexCountis the number of entries in thepQueueFamilyIndicesarray. -
pQueueFamilyIndicesis a list of queue families that will access this image (ignored ifsharingModeis notVK_SHARING_MODE_CONCURRENT). -
initialLayoutis a VkImageLayout value specifying the initial VkImageLayout of all image subresources of the image. See Image Layouts.
Images created with tiling equal to VK_IMAGE_TILING_LINEAR have
further restrictions on their limits and capabilities compared to images
created with tiling equal to VK_IMAGE_TILING_OPTIMAL.
Creation of images with tiling VK_IMAGE_TILING_LINEAR may not be
supported unless other parameters meet all of the constraints:
-
imageTypeisVK_IMAGE_TYPE_2D -
formatis not a depth/stencil format -
mipLevelsis 1 -
arrayLayersis 1 -
samplesisVK_SAMPLE_COUNT_1_BIT -
usageonly includesVK_IMAGE_USAGE_TRANSFER_SRC_BITand/orVK_IMAGE_USAGE_TRANSFER_DST_BIT
Implementations may support additional limits and capabilities beyond those listed above.
To query an implementation’s specific capabilities for a given combination
of format, imageType, tiling, usage,
VkExternalMemoryImageCreateInfo::handleTypes
and flags, call
vkGetPhysicalDeviceImageFormatProperties2.
The return value specifies whether that combination of image settings is
supported.
On success, the VkImageFormatProperties output parameter specifies the
set of valid samples bits and the limits for extent,
mipLevels, arrayLayers, and maxResourceSize.
Even if
vkGetPhysicalDeviceImageFormatProperties2.
returns success and the parameters to vkCreateImage are all within the
returned limits, vkCreateImage must fail and return
VK_ERROR_OUT_OF_DEVICE_MEMORY if the resulting size of the image would
be larger than maxResourceSize.
To determine the set of valid usage bits for a given format, call
vkGetPhysicalDeviceFormatProperties.
|
Note
For images created without For images created with |
If the pNext chain includes a
VkDedicatedAllocationImageCreateInfoNV structure, then that structure
includes an enable controlling whether the image will have a dedicated
memory allocation bound to it.
The VkDedicatedAllocationImageCreateInfoNV structure is defined as:
typedef struct VkDedicatedAllocationImageCreateInfoNV {
VkStructureType sType;
const void* pNext;
VkBool32 dedicatedAllocation;
} VkDedicatedAllocationImageCreateInfoNV;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
dedicatedAllocationspecifies whether the image will have a dedicated allocation bound to it.
|
Note
Using a dedicated allocation for color and depth/stencil attachments or other large images may improve performance on some devices. |
To define a set of external memory handle types that may be used as backing
store for an image, add a VkExternalMemoryImageCreateInfo structure to
the pNext chain of the VkImageCreateInfo structure.
The VkExternalMemoryImageCreateInfo structure is defined as:
typedef struct VkExternalMemoryImageCreateInfo {
VkStructureType sType;
const void* pNext;
VkExternalMemoryHandleTypeFlags handleTypes;
} VkExternalMemoryImageCreateInfo;
or the equivalent
typedef VkExternalMemoryImageCreateInfo VkExternalMemoryImageCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
handleTypesis a bitmask of VkExternalMemoryHandleTypeFlagBits specifying one or more external memory handle types.
If the pNext chain includes a VkExternalMemoryImageCreateInfoNV
structure, then that structure defines a set of external memory handle types
that may be used as backing store for the image.
The VkExternalMemoryImageCreateInfoNV structure is defined as:
typedef struct VkExternalMemoryImageCreateInfoNV {
VkStructureType sType;
const void* pNext;
VkExternalMemoryHandleTypeFlagsNV handleTypes;
} VkExternalMemoryImageCreateInfoNV;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
handleTypesis a bitmask of VkExternalMemoryHandleTypeFlagBitsNV specifying one or more external memory handle types.
To create an image with an
external
format, include an instance of VkExternalFormatANDROID in the
pNext chain of VkImageCreateInfo.
VkExternalFormatANDROID is defined as:
typedef struct VkExternalFormatANDROID {
VkStructureType sType;
void* pNext;
uint64_t externalFormat;
} VkExternalFormatANDROID;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
externalFormatis an implementation-defined identifier for the external format
If externalFormat is zero, the effect is as if the
VkExternalFormatANDROID structure was not present.
Otherwise, the image will have the specified external format, and
VkImageCreateInfo::format must be VK_FORMAT_UNDEFINED.
If the pNext chain of VkImageCreateInfo includes a
VkImageSwapchainCreateInfoKHR structure, then that structure includes
a swapchain handle indicating that the image will be bound to memory from
that swapchain.
The VkImageSwapchainCreateInfoKHR structure is defined as:
typedef struct VkImageSwapchainCreateInfoKHR {
VkStructureType sType;
const void* pNext;
VkSwapchainKHR swapchain;
} VkImageSwapchainCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
swapchainis VK_NULL_HANDLE or a handle of a swapchain that the image will be bound to.
If the pNext list of VkImageCreateInfo includes a
VkImageFormatListCreateInfoKHR structure, then that structure contains
a list of all formats that can be used when creating views of this image.
The VkImageFormatListCreateInfoKHR structure is defined as:
typedef struct VkImageFormatListCreateInfoKHR {
VkStructureType sType;
const void* pNext;
uint32_t viewFormatCount;
const VkFormat* pViewFormats;
} VkImageFormatListCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
viewFormatCountis the number of entries in thepViewFormatsarray. -
pViewFormatsis an array which lists of all formats which can be used when creating views of this image.
If viewFormatCount is zero, pViewFormats is ignored and the
image is created as if the VkImageFormatListCreateInfoKHR structure
were not included in the pNext list of VkImageCreateInfo.
Bits which can be set in VkImageCreateInfo::usage, specifying
intended usage of an image, are:
typedef enum VkImageUsageFlagBits {
VK_IMAGE_USAGE_TRANSFER_SRC_BIT = 0x00000001,
VK_IMAGE_USAGE_TRANSFER_DST_BIT = 0x00000002,
VK_IMAGE_USAGE_SAMPLED_BIT = 0x00000004,
VK_IMAGE_USAGE_STORAGE_BIT = 0x00000008,
VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT = 0x00000010,
VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT = 0x00000020,
VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT = 0x00000040,
VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT = 0x00000080,
} VkImageUsageFlagBits;
-
VK_IMAGE_USAGE_TRANSFER_SRC_BITspecifies that the image can be used as the source of a transfer command. -
VK_IMAGE_USAGE_TRANSFER_DST_BITspecifies that the image can be used as the destination of a transfer command. -
VK_IMAGE_USAGE_SAMPLED_BITspecifies that the image can be used to create aVkImageViewsuitable for occupying aVkDescriptorSetslot either of typeVK_DESCRIPTOR_TYPE_SAMPLED_IMAGEorVK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, and be sampled by a shader. -
VK_IMAGE_USAGE_STORAGE_BITspecifies that the image can be used to create aVkImageViewsuitable for occupying aVkDescriptorSetslot of typeVK_DESCRIPTOR_TYPE_STORAGE_IMAGE. -
VK_IMAGE_USAGE_COLOR_ATTACHMENT_BITspecifies that the image can be used to create aVkImageViewsuitable for use as a color or resolve attachment in aVkFramebuffer. -
VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BITspecifies that the image can be used to create aVkImageViewsuitable for use as a depth/stencil attachment in aVkFramebuffer. -
VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BITspecifies that the memory bound to this image will have been allocated with theVK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT(see Memory Allocation for more detail). This bit can be set for any image that can be used to create aVkImageViewsuitable for use as a color, resolve, depth/stencil, or input attachment. -
VK_IMAGE_USAGE_INPUT_ATTACHMENT_BITspecifies that the image can be used to create aVkImageViewsuitable for occupyingVkDescriptorSetslot of typeVK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT; be read from a shader as an input attachment; and be used as an input attachment in a framebuffer.
typedef VkFlags VkImageUsageFlags;
VkImageUsageFlags is a bitmask type for setting a mask of zero or more
VkImageUsageFlagBits.
Bits which can be set in VkImageCreateInfo::flags, specifying
additional parameters of an image, are:
typedef enum VkImageCreateFlagBits {
VK_IMAGE_CREATE_SPARSE_BINDING_BIT = 0x00000001,
VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT = 0x00000002,
VK_IMAGE_CREATE_SPARSE_ALIASED_BIT = 0x00000004,
VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT = 0x00000008,
VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT = 0x00000010,
VK_IMAGE_CREATE_ALIAS_BIT = 0x00000400,
VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT = 0x00000040,
VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT = 0x00000020,
VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT = 0x00000080,
VK_IMAGE_CREATE_EXTENDED_USAGE_BIT = 0x00000100,
VK_IMAGE_CREATE_PROTECTED_BIT = 0x00000800,
VK_IMAGE_CREATE_DISJOINT_BIT = 0x00000200,
VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT = 0x00001000,
VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT_KHR = VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT,
VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT_KHR = VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT,
VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT_KHR = VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT,
VK_IMAGE_CREATE_EXTENDED_USAGE_BIT_KHR = VK_IMAGE_CREATE_EXTENDED_USAGE_BIT,
VK_IMAGE_CREATE_DISJOINT_BIT_KHR = VK_IMAGE_CREATE_DISJOINT_BIT,
VK_IMAGE_CREATE_ALIAS_BIT_KHR = VK_IMAGE_CREATE_ALIAS_BIT,
} VkImageCreateFlagBits;
-
VK_IMAGE_CREATE_SPARSE_BINDING_BITspecifies that the image will be backed using sparse memory binding. -
VK_IMAGE_CREATE_SPARSE_RESIDENCY_BITspecifies that the image can be partially backed using sparse memory binding. Images created with this flag must also be created with theVK_IMAGE_CREATE_SPARSE_BINDING_BITflag. -
VK_IMAGE_CREATE_SPARSE_ALIASED_BITspecifies that the image will be backed using sparse memory binding with memory ranges that might also simultaneously be backing another image (or another portion of the same image). Images created with this flag must also be created with theVK_IMAGE_CREATE_SPARSE_BINDING_BITflag -
VK_IMAGE_CREATE_MUTABLE_FORMAT_BITspecifies that the image can be used to create aVkImageViewwith a different format from the image. For multi-planar formats,VK_IMAGE_CREATE_MUTABLE_FORMAT_BITspecifies that aVkImageViewcan be created of a plane of the image. -
VK_IMAGE_CREATE_CUBE_COMPATIBLE_BITspecifies that the image can be used to create aVkImageViewof typeVK_IMAGE_VIEW_TYPE_CUBEorVK_IMAGE_VIEW_TYPE_CUBE_ARRAY. -
VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BITspecifies that the image can be used to create aVkImageViewof typeVK_IMAGE_VIEW_TYPE_2DorVK_IMAGE_VIEW_TYPE_2D_ARRAY. -
VK_IMAGE_CREATE_PROTECTED_BITspecifies that the image is a protected image. -
VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BITspecifies that the image can be used with a non-zero value of thesplitInstanceBindRegionCountmember of a VkBindImageMemoryDeviceGroupInfo structure passed into vkBindImageMemory2. This flag also has the effect of making the image use the standard sparse image block dimensions. -
VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BITspecifies that the image having a compressed format can be used to create aVkImageViewwith an uncompressed format where each texel in the image view corresponds to a compressed texel block of the image. -
VK_IMAGE_CREATE_EXTENDED_USAGE_BITspecifies that the image can be created with usage flags that are not supported for the format the image is created with but are supported for at least one format aVkImageViewcreated from the image can have. -
VK_IMAGE_CREATE_DISJOINT_BITspecifies that an image with a multi-planar format must have each plane separately bound to memory, rather than having a single memory binding for the whole image; the presence of this bit distinguishes a disjoint image from an image without this bit set. -
VK_IMAGE_CREATE_ALIAS_BITspecifies that two images created with the same creation parameters and aliased to the same memory can interpret the contents of the memory consistently with each other, subject to the rules described in the Memory Aliasing section. This flag further specifies that each plane of a disjoint image can share an in-memory non-linear representation with single-plane images, and that a single-plane image can share an in-memory non-linear representation with a plane of a multi-planar disjoint image, according to the rules in Compatible formats of planes of multi-planar formats. If thepNextchain includes a VkExternalMemoryImageCreateInfo or VkExternalMemoryImageCreateInfoNV structure whosehandleTypesmember is not0, it is as ifVK_IMAGE_CREATE_ALIAS_BITis set. -
VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXTspecifies that an image with a depth or depth/stencil format can be used with custom sample locations when used as a depth/stencil attachment.
See Sparse Resource Features and Sparse Physical Device Features for more details.
typedef VkFlags VkImageCreateFlags;
VkImageCreateFlags is a bitmask type for setting a mask of zero or
more VkImageCreateFlagBits.
Possible values of VkImageCreateInfo::imageType, specifying the
basic dimensionality of an image, are:
typedef enum VkImageType {
VK_IMAGE_TYPE_1D = 0,
VK_IMAGE_TYPE_2D = 1,
VK_IMAGE_TYPE_3D = 2,
} VkImageType;
-
VK_IMAGE_TYPE_1Dspecifies a one-dimensional image. -
VK_IMAGE_TYPE_2Dspecifies a two-dimensional image. -
VK_IMAGE_TYPE_3Dspecifies a three-dimensional image.
Possible values of VkImageCreateInfo::tiling, specifying the
tiling arrangement of data elements in an image, are:
typedef enum VkImageTiling {
VK_IMAGE_TILING_OPTIMAL = 0,
VK_IMAGE_TILING_LINEAR = 1,
} VkImageTiling;
-
VK_IMAGE_TILING_OPTIMALspecifies optimal tiling (texels are laid out in an implementation-dependent arrangement, for more optimal memory access). -
VK_IMAGE_TILING_LINEARspecifies linear tiling (texels are laid out in memory in row-major order, possibly with some padding on each row).
To query the host access layout of an image subresource, for an image created with linear tiling, call:
void vkGetImageSubresourceLayout(
VkDevice device,
VkImage image,
const VkImageSubresource* pSubresource,
VkSubresourceLayout* pLayout);
-
deviceis the logical device that owns the image. -
imageis the image whose layout is being queried. -
pSubresourceis a pointer to a VkImageSubresource structure selecting a specific image for the image subresource. -
pLayoutpoints to a VkSubresourceLayout structure in which the layout is returned.
If the VkFormat of image is a
multi-planar format,
vkGetImageSubresourceLayout describes one plane of the image.
vkGetImageSubresourceLayout is invariant for the lifetime of a single
image.
However, the subresource layout of images in Android hardware buffer
external memory isn’t known until the image has been bound to memory, so
calling vkGetImageSubresourceLayout for such an image before it has
been bound will result in undefined behavior.
The VkImageSubresource structure is defined as:
typedef struct VkImageSubresource {
VkImageAspectFlags aspectMask;
uint32_t mipLevel;
uint32_t arrayLayer;
} VkImageSubresource;
-
aspectMaskis a VkImageAspectFlags selecting the image aspect. -
mipLevelselects the mipmap level. -
arrayLayerselects the array layer.
Information about the layout of the image subresource is returned in a
VkSubresourceLayout structure:
typedef struct VkSubresourceLayout {
VkDeviceSize offset;
VkDeviceSize size;
VkDeviceSize rowPitch;
VkDeviceSize arrayPitch;
VkDeviceSize depthPitch;
} VkSubresourceLayout;
-
offsetis the byte offset from the start of the image where the image subresource begins. -
sizeis the size in bytes of the image subresource.sizeincludes any extra memory that is required based onrowPitch. -
rowPitchdescribes the number of bytes between each row of texels in an image. -
arrayPitchdescribes the number of bytes between each array layer of an image. -
depthPitchdescribes the number of bytes between each slice of 3D image.
For images created with linear tiling, rowPitch, arrayPitch and
depthPitch describe the layout of the image subresource in linear
memory.
For uncompressed formats, rowPitch is the number of bytes between
texels with the same x coordinate in adjacent rows (y coordinates differ by
one).
arrayPitch is the number of bytes between texels with the same x and y
coordinate in adjacent array layers of the image (array layer values differ
by one).
depthPitch is the number of bytes between texels with the same x and y
coordinate in adjacent slices of a 3D image (z coordinates differ by one).
Expressed as an addressing formula, the starting byte of a texel in the
image subresource has address:
// (x,y,z,layer) are in texel coordinates
address(x,y,z,layer) = layer*arrayPitch + z*depthPitch + y*rowPitch + x*elementSize + offset
For compressed formats, the rowPitch is the number of bytes between
compressed texel blocks in adjacent rows.
arrayPitch is the number of bytes between compressed texel blocks in
adjacent array layers.
depthPitch is the number of bytes between compressed texel blocks in
adjacent slices of a 3D image.
// (x,y,z,layer) are in compressed texel block coordinates
address(x,y,z,layer) = layer*arrayPitch + z*depthPitch + y*rowPitch + x*compressedTexelBlockByteSize + offset;
arrayPitch is undefined for images that were not created as arrays.
depthPitch is defined only for 3D images.
For
single-plane
color formats, the aspectMask member of VkImageSubresource must
be VK_IMAGE_ASPECT_COLOR_BIT.
For depth/stencil formats, aspectMask must be either
VK_IMAGE_ASPECT_DEPTH_BIT or VK_IMAGE_ASPECT_STENCIL_BIT.
On implementations that store depth and stencil aspects separately, querying
each of these image subresource layouts will return a different offset
and size representing the region of memory used for that aspect.
On implementations that store depth and stencil aspects interleaved, the
same offset and size are returned and represent the interleaved
memory allocation.
For multi-planar
formats, the aspectMask member of VkImageSubresource must be
VK_IMAGE_ASPECT_PLANE_0_BIT, VK_IMAGE_ASPECT_PLANE_1_BIT, or
(for 3-plane formats only) VK_IMAGE_ASPECT_PLANE_2_BIT.
Querying each of these image subresource layouts will return a different
offset and size representing the region of memory used for that
plane.
To destroy an image, call:
void vkDestroyImage(
VkDevice device,
VkImage image,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the image. -
imageis the image to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
11.4. Image Layouts
Images are stored in implementation-dependent opaque layouts in memory.
Each layout has limitations on what kinds of operations are supported for
image subresources using the layout.
At any given time, the data representing an image subresource in memory
exists in a particular layout which is determined by the most recent layout
transition that was performed on that image subresource.
Applications have control over which layout each image subresource uses, and
can transition an image subresource from one layout to another.
Transitions can happen with an image memory barrier, included as part of a
vkCmdPipelineBarrier or a vkCmdWaitEvents command buffer command
(see Image Memory Barriers), or as part of a subpass
dependency within a render pass (see VkSubpassDependency).
The image layout is per-image subresource, and separate image subresources
of the same image can be in different layouts at the same time with one
exception - depth and stencil aspects of a given image subresource must
always be in the same layout.
|
Note
Each layout may offer optimal performance for a specific usage of image
memory.
For example, an image with a layout of
|
Upon creation, all image subresources of an image are initially in the same
layout, where that layout is selected by the
VkImageCreateInfo::initialLayout member.
The initialLayout must be either VK_IMAGE_LAYOUT_UNDEFINED or
VK_IMAGE_LAYOUT_PREINITIALIZED.
If it is VK_IMAGE_LAYOUT_PREINITIALIZED, then the image data can be
preinitialized by the host while using this layout, and the transition away
from this layout will preserve that data.
If it is VK_IMAGE_LAYOUT_UNDEFINED, then the contents of the data are
considered to be undefined, and the transition away from this layout is not
guaranteed to preserve that data.
For either of these initial layouts, any image subresources must be
transitioned to another layout before they are accessed by the device.
Host access to image memory is only well-defined for images created with
VK_IMAGE_TILING_LINEAR tiling and for image subresources of those
images which are currently in either the
VK_IMAGE_LAYOUT_PREINITIALIZED or VK_IMAGE_LAYOUT_GENERAL
layout.
Calling vkGetImageSubresourceLayout for a linear image returns a
subresource layout mapping that is valid for either of those image layouts.
The set of image layouts consists of:
typedef enum VkImageLayout {
VK_IMAGE_LAYOUT_UNDEFINED = 0,
VK_IMAGE_LAYOUT_GENERAL = 1,
VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL = 2,
VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL = 3,
VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL = 4,
VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL = 5,
VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL = 6,
VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL = 7,
VK_IMAGE_LAYOUT_PREINITIALIZED = 8,
VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL = 1000117000,
VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL = 1000117001,
VK_IMAGE_LAYOUT_PRESENT_SRC_KHR = 1000001002,
VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR = 1000111000,
VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL_KHR = VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL,
VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL_KHR = VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL,
} VkImageLayout;
The type(s) of device access supported by each layout are:
-
VK_IMAGE_LAYOUT_UNDEFINEDdoes not support device access. This layout must only be used as theinitialLayoutmember ofVkImageCreateInfoorVkAttachmentDescription, or as theoldLayoutin an image transition. When transitioning out of this layout, the contents of the memory are not guaranteed to be preserved. -
VK_IMAGE_LAYOUT_PREINITIALIZEDdoes not support device access. This layout must only be used as theinitialLayoutmember ofVkImageCreateInfoorVkAttachmentDescription, or as theoldLayoutin an image transition. When transitioning out of this layout, the contents of the memory are preserved. This layout is intended to be used as the initial layout for an image whose contents are written by the host, and hence the data can be written to memory immediately, without first executing a layout transition. Currently,VK_IMAGE_LAYOUT_PREINITIALIZEDis only useful withVK_IMAGE_TILING_LINEARimages because there is not a standard layout defined forVK_IMAGE_TILING_OPTIMALimages. -
VK_IMAGE_LAYOUT_GENERALsupports all types of device access. -
VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMALmust only be used as a color or resolve attachment in aVkFramebuffer. This layout is valid only for image subresources of images created with theVK_IMAGE_USAGE_COLOR_ATTACHMENT_BITusage bit enabled. -
VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMALmust only be used as a depth/stencil attachment in aVkFramebuffer. This layout is valid only for image subresources of images created with theVK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BITusage bit enabled. -
VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMALmust only be used as a read-only depth/stencil attachment in aVkFramebufferand/or as a read-only image in a shader (which can be read as a sampled image, combined image/sampler and/or input attachment). This layout is valid only for image subresources of images created with theVK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BITusage bit enabled. Only image subresources of images created withVK_IMAGE_USAGE_SAMPLED_BITcan be used as a sampled image or combined image/sampler in a shader. Similarly, only image subresources of images created withVK_IMAGE_USAGE_INPUT_ATTACHMENT_BITcan be used as input attachments. -
VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL: must only be used as a depth/stencil attachment in aVkFramebuffer, where the depth aspect is read-only, and/or as a read-only image in a shader (which can be read as a sampled image, combined image/sampler and/or input attachment) where only the depth aspect is accessed. This layout is valid only for image subresources of images created with theVK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BITusage bit enabled. Only image subresources of images created withVK_IMAGE_USAGE_SAMPLED_BITcan be used as a sampled image or combined image/sampler in a shader. Similarly, only image subresources of images created withVK_IMAGE_USAGE_INPUT_ATTACHMENT_BITcan be used as input attachments. -
VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL: must only be used as a depth/stencil attachment in aVkFramebuffer, where the stencil aspect is read-only, and/or as a read-only image in a shader (which can be read as a sampled image, combined image/sampler and/or input attachment) where only the stencil aspect is accessed. This layout is valid only for image subresources of images created with theVK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BITusage bit enabled. Only image subresources of images created withVK_IMAGE_USAGE_SAMPLED_BITcan be used as a sampled image or combined image/sampler in a shader. Similarly, only image subresources of images created withVK_IMAGE_USAGE_INPUT_ATTACHMENT_BITcan be used as input attachments. -
VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMALmust only be used as a read-only image in a shader (which can be read as a sampled image, combined image/sampler and/or input attachment). This layout is valid only for image subresources of images created with theVK_IMAGE_USAGE_SAMPLED_BITorVK_IMAGE_USAGE_INPUT_ATTACHMENT_BITusage bit enabled. -
VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMALmust only be used as a source image of a transfer command (see the definition ofVK_PIPELINE_STAGE_TRANSFER_BIT). This layout is valid only for image subresources of images created with theVK_IMAGE_USAGE_TRANSFER_SRC_BITusage bit enabled. -
VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMALmust only be used as a destination image of a transfer command. This layout is valid only for image subresources of images created with theVK_IMAGE_USAGE_TRANSFER_DST_BITusage bit enabled. -
VK_IMAGE_LAYOUT_PRESENT_SRC_KHRmust only be used for presenting a presentable image for display. A swapchain’s image must be transitioned to this layout before calling vkQueuePresentKHR, and must be transitioned away from this layout after calling vkAcquireNextImageKHR. -
VK_IMAGE_LAYOUT_SHARED_PRESENT_KHRis valid only for shared presentable images, and must be used for any usage the image supports.
The layout of each image subresource is not a state of the image subresource
itself, but is rather a property of how the data in memory is organized, and
thus for each mechanism of accessing an image in the API the application
must specify a parameter or structure member that indicates which image
layout the image subresource(s) are considered to be in when the image will
be accessed.
For transfer commands, this is a parameter to the command (see Clear Commands
and Copy Commands).
For use as a framebuffer attachment, this is a member in the substructures
of the VkRenderPassCreateInfo (see Render Pass).
For use in a descriptor set, this is a member in the
VkDescriptorImageInfo structure (see Descriptor Set Updates).
At the time that any command buffer command accessing an image executes on
any queue, the layouts of the image subresources that are accessed must all
match the layout specified via the API controlling those accesses.
When performing a layout transition on an image subresource, the old layout
value must either equal the current layout of the image subresource (at the
time the transition executes), or else be VK_IMAGE_LAYOUT_UNDEFINED
(implying that the contents of the image subresource need not be preserved).
The new layout used in a transition must not be
VK_IMAGE_LAYOUT_UNDEFINED or VK_IMAGE_LAYOUT_PREINITIALIZED.
The image layout of each image subresource of a depth/stencil image created
with VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT is
dependent on the last sample locations used to render to the image
subresource as a depth/stencil attachment, thus applications must provide
the same sample locations that were last used to render to the given image
subresource whenever a layout transition of the image subresource happens,
otherwise the contents of the depth aspect of the image subresource become
undefined.
In addition, depth reads from a depth/stencil attachment referring to an
image subresource range of a depth/stencil image created with
VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT using
different sample locations than what have been last used to perform depth
writes to the image subresources of the same image subresource range produce
undefined results.
Similarly, depth writes to a depth/stencil attachment referring to an image
subresource range of a depth/stencil image created with
VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT using
different sample locations than what have been last used to perform depth
writes to the image subresources of the same image subresource range make
the contents of the depth aspect of those image subresources undefined.
11.5. Image Views
Image objects are not directly accessed by pipeline shaders for reading or writing image data. Instead, image views representing contiguous ranges of the image subresources and containing additional metadata are used for that purpose. Views must be created on images of compatible types, and must represent a valid subset of image subresources.
Image views are represented by VkImageView handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkImageView)
The types of image views that can be created are:
typedef enum VkImageViewType {
VK_IMAGE_VIEW_TYPE_1D = 0,
VK_IMAGE_VIEW_TYPE_2D = 1,
VK_IMAGE_VIEW_TYPE_3D = 2,
VK_IMAGE_VIEW_TYPE_CUBE = 3,
VK_IMAGE_VIEW_TYPE_1D_ARRAY = 4,
VK_IMAGE_VIEW_TYPE_2D_ARRAY = 5,
VK_IMAGE_VIEW_TYPE_CUBE_ARRAY = 6,
} VkImageViewType;
The exact image view type is partially implicit, based on the image’s type
and sample count, as well as the view creation parameters as described in
the image view compatibility table
for vkCreateImageView.
This table also shows which SPIR-V OpTypeImage Dim and
Arrayed parameters correspond to each image view type.
To create an image view, call:
VkResult vkCreateImageView(
VkDevice device,
const VkImageViewCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkImageView* pView);
-
deviceis the logical device that creates the image view. -
pCreateInfois a pointer to an instance of theVkImageViewCreateInfostructure containing parameters to be used to create the image view. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pViewpoints to aVkImageViewhandle in which the resulting image view object is returned.
Some of the image creation parameters are inherited by the view.
In particular, image view creation inherits the implicit parameter
usage specifying the allowed usages of the image view that, by
default, takes the value of the corresponding usage parameter
specified in VkImageCreateInfo at image creation time.
This implicit parameter can be overriden by chaining a
VkImageViewUsageCreateInfo structure through the pNext member to
VkImageViewCreateInfo as described later in this section.
The remaining parameters are contained in the pCreateInfo.
The VkImageViewCreateInfo structure is defined as:
typedef struct VkImageViewCreateInfo {
VkStructureType sType;
const void* pNext;
VkImageViewCreateFlags flags;
VkImage image;
VkImageViewType viewType;
VkFormat format;
VkComponentMapping components;
VkImageSubresourceRange subresourceRange;
} VkImageViewCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
imageis aVkImageon which the view will be created. -
viewTypeis an VkImageViewType value specifying the type of the image view. -
formatis a VkFormat describing the format and type used to interpret data elements in the image. -
componentsis a VkComponentMapping specifies a remapping of color components (or of depth or stencil components after they have been converted into color components). -
subresourceRangeis a VkImageSubresourceRange selecting the set of mipmap levels and array layers to be accessible to the view.
If image was created with the VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT
flag,
and if the format of the image is not
multi-planar,
format can be different from the image’s format, but if
image was created without the
VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT flag and
they are not equal they must be compatible.
Image format compatibility is defined in the
Format Compatibility Classes
section.
Views of compatible formats will have the same mapping between texel
coordinates and memory locations irrespective of the format, with only
the interpretation of the bit pattern changing.
|
Note
Values intended to be used with one view format may not be exactly preserved when written or read through a different format. For example, an integer value that happens to have the bit pattern of a floating point denorm or NaN may be flushed or canonicalized when written or read through a view with a floating point format. Similarly, a value written through a signed normalized format that has a bit pattern exactly equal to -2b may be changed to -2b + 1 as described in Conversion from Normalized Fixed-Point to Floating-Point. |
If image was created with the
VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT flag, format
must be compatible with the image’s format as described above, or must
be an uncompressed format in which case it must be size-compatible with
the image’s format, as defined for
copying data between images In
this case the resulting image view’s texel dimensions equal the dimensions
of the selected mip level divided by the compressed texel block size and
rounded up.
If the image view is to be used with a sampler which supports
sampler Y’CBCR conversion, an identically
defined object of type VkSamplerYcbcrConversion to that used to
create the sampler must be passed to vkCreateImageView in a
VkSamplerYcbcrConversionInfo added to the pNext chain of
VkImageViewCreateInfo.
If the image has a
multi-planar
format and subresourceRange.aspectMask is
VK_IMAGE_ASPECT_COLOR_BIT, format must be identical to the
image format, and the sampler to be used with the image view must
enable sampler Y’CBCR conversion.
If image was created with the VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT
and the image has a
multi-planar
format, and if subresourceRange.aspectMask is
VK_IMAGE_ASPECT_PLANE_0_BIT, VK_IMAGE_ASPECT_PLANE_1_BIT, or
VK_IMAGE_ASPECT_PLANE_2_BIT, format must be
compatible with the corresponding
plane of the image, and the sampler to be used with the image view must not
enable sampler Y’CBCR conversion.
The width and height of the single-plane image view must be
derived from the multi-planar image’s dimensions in the manner listed for
plane compatibility for the plane.
Any view of an image plane will have the same mapping between texel coordinates and memory locations as used by the channels of the color aspect, subject to the formulae relating texel coordinates to lower-resolution planes as described in Chroma Reconstruction. That is, if an R or B plane has a reduced resolution relative to the G plane of the multi-planar image, the image view operates using the (uplane, vplane) unnormalized coordinates of the reduced-resolution plane, and these coordinates access the same memory locations as the (ucolor, vcolor) unnormalized coordinates of the color aspect for which chroma reconstruction operations operate on the same (uplane, vplane) or (iplane, jplane) coordinates.
| Dim, Arrayed, MS | Image parameters | View parameters |
|---|---|---|
|
|
|
1D, 0, 0 |
|
|
1D, 1, 0 |
|
|
2D, 0, 0 |
|
|
2D, 1, 0 |
|
|
2D, 0, 1 |
|
|
2D, 1, 1 |
|
|
CUBE, 0, 0 |
|
|
CUBE, 1, 0 |
|
|
3D, 0, 0 |
|
|
3D, 0, 0 |
|
|
3D, 0, 0 |
|
|
typedef VkFlags VkImageViewCreateFlags;
VkImageViewCreateFlags is a bitmask type for setting a mask, but is
currently reserved for future use.
The set of usages for the created image view can be restricted compared to
the parent image’s usage flags by chaining a
VkImageViewUsageCreateInfo structure through the pNext member to
VkImageViewCreateInfo.
The VkImageViewUsageCreateInfo structure is defined as:
typedef struct VkImageViewUsageCreateInfo {
VkStructureType sType;
const void* pNext;
VkImageUsageFlags usage;
} VkImageViewUsageCreateInfo;
or the equivalent
typedef VkImageViewUsageCreateInfo VkImageViewUsageCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
usageis a bitmask describing the allowed usages of the image view. See VkImageUsageFlagBits for a description of the supported bits.
When this structure is chained to VkImageViewCreateInfo the
usage field overrides the implicit usage parameter inherited
from image creation time and its value is used instead for the purposes of
determining the valid usage conditions of VkImageViewCreateInfo.
The VkImageSubresourceRange structure is defined as:
typedef struct VkImageSubresourceRange {
VkImageAspectFlags aspectMask;
uint32_t baseMipLevel;
uint32_t levelCount;
uint32_t baseArrayLayer;
uint32_t layerCount;
} VkImageSubresourceRange;
-
aspectMaskis a bitmask of VkImageAspectFlagBits specifying which aspect(s) of the image are included in the view. -
baseMipLevelis the first mipmap level accessible to the view. -
levelCountis the number of mipmap levels (starting frombaseMipLevel) accessible to the view. -
baseArrayLayeris the first array layer accessible to the view. -
layerCountis the number of array layers (starting frombaseArrayLayer) accessible to the view.
The number of mipmap levels and array layers must be a subset of the image
subresources in the image.
If an application wants to use all mip levels or layers in an image after
the baseMipLevel or baseArrayLayer, it can set levelCount
and layerCount to the special values VK_REMAINING_MIP_LEVELS and
VK_REMAINING_ARRAY_LAYERS without knowing the exact number of mip
levels or layers.
For cube and cube array image views, the layers of the image view starting
at baseArrayLayer correspond to faces in the order +X, -X, +Y, -Y, +Z,
-Z.
For cube arrays, each set of six sequential layers is a single cube, so the
number of cube maps in a cube map array view is layerCount / 6, and
image array layer (baseArrayLayer + i) is face index
(i mod 6) of cube i / 6.
If the number of layers in the view, whether set explicitly in
layerCount or implied by VK_REMAINING_ARRAY_LAYERS, is not a
multiple of 6, behavior when indexing the last cube is undefined.
aspectMask must be only VK_IMAGE_ASPECT_COLOR_BIT,
VK_IMAGE_ASPECT_DEPTH_BIT or VK_IMAGE_ASPECT_STENCIL_BIT if
format is a color, depth-only or stencil-only format,
respectively, except if format is a
multi-planar format.
If using a depth/stencil format with both depth and stencil components,
aspectMask must include at least one of
VK_IMAGE_ASPECT_DEPTH_BIT and VK_IMAGE_ASPECT_STENCIL_BIT, and
can include both.
When the VkImageSubresourceRange structure is used to select a subset
of the slices of a 3D image’s mip level in order to create a 2D or 2D array
image view of a 3D image created with
VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT, baseArrayLayer and
layerCount specify the first slice index and the number of slices to
include in the created image view.
Such an image view can be used as a framebuffer attachment that refers only
to the specified range of slices of the selected mip level.
However, any layout transitions performed on such an attachment view during
a render pass instance still apply to the entire subresource referenced
which includes all the slices of the selected mip level.
When using an imageView of a depth/stencil image to populate a descriptor
set (e.g. for sampling in the shader, or for use as an input attachment),
the aspectMask must only include one bit and selects whether the
imageView is used for depth reads (i.e. using a floating-point sampler or
input attachment in the shader) or stencil reads (i.e. using an unsigned
integer sampler or input attachment in the shader).
When an imageView of a depth/stencil image is used as a depth/stencil
framebuffer attachment, the aspectMask is ignored and both depth and
stencil image subresources are used.
The components member is of type VkComponentMapping, and
describes a remapping from components of the image to components of the
vector returned by shader image instructions.
This remapping must be identity for storage image descriptors, input
attachment descriptors,
framebuffer attachments, and any VkImageView used with a combined
image sampler that enables sampler Y’CBCR
conversion.
When creating a VkImageView, if sampler
Y’CBCR conversion is enabled in the sampler, the aspectMask of a
subresourceRange used by the VkImageView must be
VK_IMAGE_ASPECT_COLOR_BIT.
When creating a VkImageView, if sampler Y’CBCR conversion is not
enabled in the sampler and the image format is
multi-planar, the
image must have been created with VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT,
and the aspectMask of the VkImageView’s subresourceRange
must be VK_IMAGE_ASPECT_PLANE_0_BIT,
VK_IMAGE_ASPECT_PLANE_1_BIT or VK_IMAGE_ASPECT_PLANE_2_BIT.
Bits which can be set in an aspect mask to specify aspects of an image for purposes such as identifying a subresource, are:
typedef enum VkImageAspectFlagBits {
VK_IMAGE_ASPECT_COLOR_BIT = 0x00000001,
VK_IMAGE_ASPECT_DEPTH_BIT = 0x00000002,
VK_IMAGE_ASPECT_STENCIL_BIT = 0x00000004,
VK_IMAGE_ASPECT_METADATA_BIT = 0x00000008,
VK_IMAGE_ASPECT_PLANE_0_BIT = 0x00000010,
VK_IMAGE_ASPECT_PLANE_1_BIT = 0x00000020,
VK_IMAGE_ASPECT_PLANE_2_BIT = 0x00000040,
VK_IMAGE_ASPECT_PLANE_0_BIT_KHR = VK_IMAGE_ASPECT_PLANE_0_BIT,
VK_IMAGE_ASPECT_PLANE_1_BIT_KHR = VK_IMAGE_ASPECT_PLANE_1_BIT,
VK_IMAGE_ASPECT_PLANE_2_BIT_KHR = VK_IMAGE_ASPECT_PLANE_2_BIT,
} VkImageAspectFlagBits;
-
VK_IMAGE_ASPECT_COLOR_BITspecifies the color aspect. -
VK_IMAGE_ASPECT_DEPTH_BITspecifies the depth aspect. -
VK_IMAGE_ASPECT_STENCIL_BITspecifies the stencil aspect. -
VK_IMAGE_ASPECT_METADATA_BITspecifies the metadata aspect, used for sparse sparse resource operations.
typedef VkFlags VkImageAspectFlags;
VkImageAspectFlags is a bitmask type for setting a mask of zero or
more VkImageAspectFlagBits.
The VkComponentMapping structure is defined as:
typedef struct VkComponentMapping {
VkComponentSwizzle r;
VkComponentSwizzle g;
VkComponentSwizzle b;
VkComponentSwizzle a;
} VkComponentMapping;
-
ris a VkComponentSwizzle specifying the component value placed in the R component of the output vector. -
gis a VkComponentSwizzle specifying the component value placed in the G component of the output vector. -
bis a VkComponentSwizzle specifying the component value placed in the B component of the output vector. -
ais a VkComponentSwizzle specifying the component value placed in the A component of the output vector.
Possible values of the members of VkComponentMapping, specifying the component values placed in each component of the output vector, are:
typedef enum VkComponentSwizzle {
VK_COMPONENT_SWIZZLE_IDENTITY = 0,
VK_COMPONENT_SWIZZLE_ZERO = 1,
VK_COMPONENT_SWIZZLE_ONE = 2,
VK_COMPONENT_SWIZZLE_R = 3,
VK_COMPONENT_SWIZZLE_G = 4,
VK_COMPONENT_SWIZZLE_B = 5,
VK_COMPONENT_SWIZZLE_A = 6,
} VkComponentSwizzle;
-
VK_COMPONENT_SWIZZLE_IDENTITYspecifies that the component is set to the identity swizzle. -
VK_COMPONENT_SWIZZLE_ZEROspecifies that the component is set to zero. -
VK_COMPONENT_SWIZZLE_ONEspecifies that the component is set to either 1 or 1.0, depending on whether the type of the image view format is integer or floating-point respectively, as determined by the Format Definition section for each VkFormat. -
VK_COMPONENT_SWIZZLE_Rspecifies that the component is set to the value of the R component of the image. -
VK_COMPONENT_SWIZZLE_Gspecifies that the component is set to the value of the G component of the image. -
VK_COMPONENT_SWIZZLE_Bspecifies that the component is set to the value of the B component of the image. -
VK_COMPONENT_SWIZZLE_Aspecifies that the component is set to the value of the A component of the image.
Setting the identity swizzle on a component is equivalent to setting the identity mapping on that component. That is:
| Component | Identity Mapping |
|---|---|
|
|
|
|
|
|
|
|
To destroy an image view, call:
void vkDestroyImageView(
VkDevice device,
VkImageView imageView,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the image view. -
imageViewis the image view to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
11.6. Resource Memory Association
Resources are initially created as virtual allocations with no backing memory. Device memory is allocated separately (see Device Memory) and then associated with the resource. This association is done differently for sparse and non-sparse resources.
Resources created with any of the sparse creation flags are considered sparse resources. Resources created without these flags are non-sparse. The details on resource memory association for sparse resources is described in Sparse Resources.
Non-sparse resources must be bound completely and contiguously to a single
VkDeviceMemory object before the resource is passed as a parameter to
any of the following operations:
-
creating image or buffer views
-
updating descriptor sets
-
recording commands in a command buffer
Once bound, the memory binding is immutable for the lifetime of the resource.
In a logical device representing more than one physical device, buffer and image resources exist on all physical devices but can be bound to memory differently on each. Each such replicated resource is an instance of the resource. For sparse resources, each instance can be bound to memory arbitrarily differently. For non-sparse resources, each instance can either be bound to the local or a peer instance of the memory, or for images can be bound to rectangular regions from the local and/or peer instances. When a resource is used in a descriptor set, each physical device interprets the descriptor according to its own instance’s binding to memory.
|
Note
There are no new copy commands to transfer data between physical devices. Instead, an application can create a resource with a peer mapping and use it as the source or destination of a transfer command executed by a single physical device to copy the data from one physical device to another. |
To determine the memory requirements for a buffer resource, call:
void vkGetBufferMemoryRequirements(
VkDevice device,
VkBuffer buffer,
VkMemoryRequirements* pMemoryRequirements);
-
deviceis the logical device that owns the buffer. -
bufferis the buffer to query. -
pMemoryRequirementspoints to an instance of the VkMemoryRequirements structure in which the memory requirements of the buffer object are returned.
To determine the memory requirements for an image resource which is not
created with the VK_IMAGE_CREATE_DISJOINT_BIT flag set, call:
void vkGetImageMemoryRequirements(
VkDevice device,
VkImage image,
VkMemoryRequirements* pMemoryRequirements);
-
deviceis the logical device that owns the image. -
imageis the image to query. -
pMemoryRequirementspoints to an instance of the VkMemoryRequirements structure in which the memory requirements of the image object are returned.
The VkMemoryRequirements structure is defined as:
typedef struct VkMemoryRequirements {
VkDeviceSize size;
VkDeviceSize alignment;
uint32_t memoryTypeBits;
} VkMemoryRequirements;
-
sizeis the size, in bytes, of the memory allocation required for the resource. -
alignmentis the alignment, in bytes, of the offset within the allocation required for the resource. -
memoryTypeBitsis a bitmask and contains one bit set for every supported memory type for the resource. Bitiis set if and only if the memory typeiin theVkPhysicalDeviceMemoryPropertiesstructure for the physical device is supported for the resource.
The precise size of images that will be bound to external Android hardware
buffer memory is unknown until the memory has been imported or allocated, so
calling vkGetImageMemoryRequirements with such an image before it has
been bound to memory will result in undefined behavior.
When importing Android hardware buffer memory, the allocationSize can
be determined by calling vkGetAndroidHardwareBufferPropertiesANDROID.
When allocating new memory for an image that can be exported to a Android
hardware buffer, the memory’s allocationSize must be zero; the actual
size will be determined by the dedicated image’s parameters.
After the memory has been allocated, the amount of space allocated from the
memory’s heap can be obtained by getting the image’s memory requirements or
by calling vkGetAndroidHardwareBufferPropertiesANDROID with the
Android hardware buffer exported from the memory.
The implementation guarantees certain properties about the memory requirements returned by vkGetBufferMemoryRequirements and vkGetImageMemoryRequirements:
-
The
memoryTypeBitsmember always contains at least one bit set. -
If
bufferis aVkBuffernot created with theVK_BUFFER_CREATE_SPARSE_BINDING_BITbit set, or ifimageis aVkImagethat was created with aVK_IMAGE_TILING_LINEARvalue in thetilingmember of theVkImageCreateInfostructure passed tovkCreateImage, then thememoryTypeBitsmember always contains at least one bit set corresponding to aVkMemoryTypewith apropertyFlagsthat has both theVK_MEMORY_PROPERTY_HOST_VISIBLE_BITbit and theVK_MEMORY_PROPERTY_HOST_COHERENT_BITbit set. In other words, mappable coherent memory can always be attached to these objects. -
If
bufferwas created with VkExternalMemoryBufferCreateInfo::handleTypesset to0orimagewas created with VkExternalMemoryImageCreateInfo::handleTypesset to0, thememoryTypeBitsmember always contains at least one bit set corresponding to aVkMemoryTypewith apropertyFlagsthat has theVK_MEMORY_PROPERTY_DEVICE_LOCAL_BITbit set. -
The
memoryTypeBitsmember is identical for allVkBufferobjects created with the same value for theflagsandusagemembers in theVkBufferCreateInfostructure and thehandleTypesmember of the VkExternalMemoryBufferCreateInfo structure passed tovkCreateBuffer. Further, ifusage1andusage2of type VkBufferUsageFlags are such that the bits set inusage2are a subset of the bits set inusage1, and they have the sameflagsand VkExternalMemoryBufferCreateInfo::handleTypes, then the bits set inmemoryTypeBitsreturned forusage1must be a subset of the bits set inmemoryTypeBitsreturned forusage2, for all values offlags. -
The
alignmentmember is a power of two. -
The
alignmentmember is identical for allVkBufferobjects created with the same combination of values for theusageandflagsmembers in theVkBufferCreateInfostructure passed tovkCreateBuffer. -
For images created with a color format, the
memoryTypeBitsmember is identical for allVkImageobjects created with the same combination of values for thetilingmember, theVK_IMAGE_CREATE_SPARSE_BINDING_BITbit of theflagsmember, theVK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BITbit of theflagsmember,handleTypesmember of VkExternalMemoryImageCreateInfo, and theVK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BITof theusagemember in theVkImageCreateInfostructure passed tovkCreateImage. -
For images created with a depth/stencil format, the
memoryTypeBitsmember is identical for allVkImageobjects created with the same combination of values for theformatmember, thetilingmember, theVK_IMAGE_CREATE_SPARSE_BINDING_BITbit of theflagsmember, theVK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BITbit of theflagsmember,handleTypesmember of VkExternalMemoryImageCreateInfo, and theVK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BITof theusagemember in theVkImageCreateInfostructure passed tovkCreateImage. -
If the memory requirements are for a
VkImage, thememoryTypeBitsmember must not refer to aVkMemoryTypewith apropertyFlagsthat has theVK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BITbit set if the vkGetImageMemoryRequirements::imagedid not haveVK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BITbit set in theusagemember of theVkImageCreateInfostructure passed tovkCreateImage. -
If the memory requirements are for a
VkBuffer, thememoryTypeBitsmember must not refer to aVkMemoryTypewith apropertyFlagsthat has theVK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BITbit set.NoteThe implication of this requirement is that lazily allocated memory is disallowed for buffers in all cases.
-
The
sizemember is identical for allVkBufferobjects created with the same combination of creation parameters specified inVkBufferCreateInfoand itspNextchain. -
The
sizemember is identical for allVkImageobjects created with the same combination of creation parameters specified inVkImageCreateInfoand itspNextchain.NoteThis, however, does not imply that they interpret the contents of the bound memory identically with each other. That additional guarantee, however, can be explicitly requested using
VK_IMAGE_CREATE_ALIAS_BIT.
To determine the memory requirements for a buffer resource, call:
void vkGetBufferMemoryRequirements2(
VkDevice device,
const VkBufferMemoryRequirementsInfo2* pInfo,
VkMemoryRequirements2* pMemoryRequirements);
or the equivalent command
void vkGetBufferMemoryRequirements2KHR(
VkDevice device,
const VkBufferMemoryRequirementsInfo2* pInfo,
VkMemoryRequirements2* pMemoryRequirements);
-
deviceis the logical device that owns the buffer. -
pInfois a pointer to an instance of theVkBufferMemoryRequirementsInfo2structure containing parameters required for the memory requirements query. -
pMemoryRequirementspoints to an instance of the VkMemoryRequirements2 structure in which the memory requirements of the buffer object are returned.
The VkBufferMemoryRequirementsInfo2 structure is defined as:
typedef struct VkBufferMemoryRequirementsInfo2 {
VkStructureType sType;
const void* pNext;
VkBuffer buffer;
} VkBufferMemoryRequirementsInfo2;
or the equivalent
typedef VkBufferMemoryRequirementsInfo2 VkBufferMemoryRequirementsInfo2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
bufferis the buffer to query.
To determine the memory requirements for an image resource, call:
void vkGetImageMemoryRequirements2(
VkDevice device,
const VkImageMemoryRequirementsInfo2* pInfo,
VkMemoryRequirements2* pMemoryRequirements);
or the equivalent command
void vkGetImageMemoryRequirements2KHR(
VkDevice device,
const VkImageMemoryRequirementsInfo2* pInfo,
VkMemoryRequirements2* pMemoryRequirements);
-
deviceis the logical device that owns the image. -
pInfois a pointer to an instance of theVkImageMemoryRequirementsInfo2structure containing parameters required for the memory requirements query. -
pMemoryRequirementspoints to an instance of the VkMemoryRequirements2 structure in which the memory requirements of the image object are returned.
The VkImageMemoryRequirementsInfo2 structure is defined as:
typedef struct VkImageMemoryRequirementsInfo2 {
VkStructureType sType;
const void* pNext;
VkImage image;
} VkImageMemoryRequirementsInfo2;
or the equivalent
typedef VkImageMemoryRequirementsInfo2 VkImageMemoryRequirementsInfo2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
imageis the image to query.
To determine the memory requirements for a plane of a disjoint image, add a
VkImagePlaneMemoryRequirementsInfo to the pNext chain of the
VkImageMemoryRequirementsInfo2 structure.
The VkImagePlaneMemoryRequirementsInfo structure is defined as:
typedef struct VkImagePlaneMemoryRequirementsInfo {
VkStructureType sType;
const void* pNext;
VkImageAspectFlagBits planeAspect;
} VkImagePlaneMemoryRequirementsInfo;
or the equivalent
typedef VkImagePlaneMemoryRequirementsInfo VkImagePlaneMemoryRequirementsInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
planeAspectis the aspect corresponding to the image plane to query.
The VkMemoryRequirements2 structure is defined as:
typedef struct VkMemoryRequirements2 {
VkStructureType sType;
void* pNext;
VkMemoryRequirements memoryRequirements;
} VkMemoryRequirements2;
or the equivalent
typedef VkMemoryRequirements2 VkMemoryRequirements2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
memoryRequirementsis a structure of type VkMemoryRequirements describing the memory requirements of the resource.
To determine the dedicated allocation requirements of a buffer or image
resource, add a VkMemoryDedicatedRequirements structure to the
pNext chain of the VkMemoryRequirements2 structure passed as the
pMemoryRequirements parameter of vkGetBufferMemoryRequirements2
or vkGetImageMemoryRequirements2.
The VkMemoryDedicatedRequirements structure is defined as:
typedef struct VkMemoryDedicatedRequirements {
VkStructureType sType;
void* pNext;
VkBool32 prefersDedicatedAllocation;
VkBool32 requiresDedicatedAllocation;
} VkMemoryDedicatedRequirements;
or the equivalent
typedef VkMemoryDedicatedRequirements VkMemoryDedicatedRequirementsKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
prefersDedicatedAllocationspecifies that the implementation would prefer a dedicated allocation for this resource. The application is still free to suballocate the resource but it may get better performance if a dedicated allocation is used. -
requiresDedicatedAllocationspecifies that a dedicated allocation is required for this resource.
When the implementation sets requiresDedicatedAllocation to
VK_TRUE, it must also set prefersDedicatedAllocation to
VK_TRUE.
If the VkMemoryDedicatedRequirements structure is included in the
pNext chain of the VkMemoryRequirements2 structure passed as the
pMemoryRequirements parameter of a
vkGetBufferMemoryRequirements2 call, requiresDedicatedAllocation
may be VK_TRUE under one of the following conditions:
-
The
pNextchain ofVkBufferCreateInfofor the call tovkCreateBufferused to create the buffer being queried contained an instance ofVkExternalMemoryBufferCreateInfo, and any of the handle types specified inVkExternalMemoryBufferCreateInfo::handleTypesrequires dedicated allocation, as reported by vkGetPhysicalDeviceExternalBufferProperties inVkExternalBufferProperties::externalMemoryProperties::externalMemoryFeatures, therequiresDedicatedAllocationfield will be set toVK_TRUE.
In all other cases, requiresDedicatedAllocation must be set to
VK_FALSE by the implementation whenever a
VkMemoryDedicatedRequirements structure is included in the pNext
chain of the VkMemoryRequirements2 structure passed to a call to
vkGetBufferMemoryRequirements2.
If the VkMemoryDedicatedRequirements structure is included in the
pNext chain of the VkMemoryRequirements2 structure passed as the
pMemoryRequirements parameter of a
vkGetBufferMemoryRequirements2 call and
VK_BUFFER_CREATE_SPARSE_BINDING_BIT was set in
VkBufferCreateInfo::flags when buffer was created then the
implementation must set both prefersDedicatedAllocation and
requiresDedicatedAllocation to VK_FALSE.
If the VkMemoryDedicatedRequirements structure is included in the
pNext chain of the VkMemoryRequirements2 structure passed as the
pMemoryRequirements parameter of a vkGetImageMemoryRequirements2
call, requiresDedicatedAllocation may be VK_TRUE under one of
the following conditions:
-
The
pNextchain ofVkImageCreateInfofor the call tovkCreateImageused to create the image being queried contained an instance ofVkExternalMemoryImageCreateInfo, and any of the handle types specified inVkExternalMemoryImageCreateInfo::handleTypesrequires dedicated allocation, as reported by vkGetPhysicalDeviceImageFormatProperties2 inVkExternalImageFormatProperties::externalMemoryProperties::externalMemoryFeatures, therequiresDedicatedAllocationfield will be set toVK_TRUE.
In all other cases, requiresDedicatedAllocation must be set to
VK_FALSE by the implementation whenever a
VkMemoryDedicatedRequirements structure is included in the pNext
chain of the VkMemoryRequirements2 structure passed to a call to
vkGetImageMemoryRequirements2.
If the VkMemoryDedicatedRequirements structure is included in the
pNext chain of the VkMemoryRequirements2 structure passed as the
pMemoryRequirements parameter of a vkGetImageMemoryRequirements2
call and VK_IMAGE_CREATE_SPARSE_BINDING_BIT was set in
VkImageCreateInfo::flags when image was created then the
implementation must set both prefersDedicatedAllocation and
requiresDedicatedAllocation to VK_FALSE.
To attach memory to a buffer object, call:
VkResult vkBindBufferMemory(
VkDevice device,
VkBuffer buffer,
VkDeviceMemory memory,
VkDeviceSize memoryOffset);
-
deviceis the logical device that owns the buffer and memory. -
bufferis the buffer to be attached to memory. -
memoryis aVkDeviceMemoryobject describing the device memory to attach. -
memoryOffsetis the start offset of the region ofmemorywhich is to be bound to the buffer. The number of bytes returned in theVkMemoryRequirements::sizemember inmemory, starting frommemoryOffsetbytes, will be bound to the specified buffer.
vkBindBufferMemory is equivalent to passing the same parameters
through VkBindBufferMemoryInfo to vkBindBufferMemory2.
To attach memory to buffer objects for one or more buffers at a time, call:
VkResult vkBindBufferMemory2(
VkDevice device,
uint32_t bindInfoCount,
const VkBindBufferMemoryInfo* pBindInfos);
or the equivalent command
VkResult vkBindBufferMemory2KHR(
VkDevice device,
uint32_t bindInfoCount,
const VkBindBufferMemoryInfo* pBindInfos);
-
deviceis the logical device that owns the buffers and memory. -
bindInfoCountis the number of elements inpBindInfos. -
pBindInfosis a pointer to an array of structures of type VkBindBufferMemoryInfo, describing buffers and memory to bind.
On some implementations, it may be more efficient to batch memory bindings into a single command.
VkBindBufferMemoryInfo contains members corresponding to the
parameters of vkBindBufferMemory.
The VkBindBufferMemoryInfo structure is defined as:
typedef struct VkBindBufferMemoryInfo {
VkStructureType sType;
const void* pNext;
VkBuffer buffer;
VkDeviceMemory memory;
VkDeviceSize memoryOffset;
} VkBindBufferMemoryInfo;
or the equivalent
typedef VkBindBufferMemoryInfo VkBindBufferMemoryInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
bufferis the buffer to be attached to memory. -
memoryis aVkDeviceMemoryobject describing the device memory to attach. -
memoryOffsetis the start offset of the region ofmemorywhich is to be bound to the buffer. The number of bytes returned in theVkMemoryRequirements::sizemember inmemory, starting frommemoryOffsetbytes, will be bound to the specified buffer.
typedef struct VkBindBufferMemoryDeviceGroupInfo {
VkStructureType sType;
const void* pNext;
uint32_t deviceIndexCount;
const uint32_t* pDeviceIndices;
} VkBindBufferMemoryDeviceGroupInfo;
or the equivalent
typedef VkBindBufferMemoryDeviceGroupInfo VkBindBufferMemoryDeviceGroupInfoKHR;
If the pNext list of VkBindBufferMemoryInfo includes a
VkBindBufferMemoryDeviceGroupInfo structure, then that structure
determines how memory is bound to buffers across multiple devices in a
device group.
The VkBindBufferMemoryDeviceGroupInfo structure is defined as:
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
deviceIndexCountis the number of elements inpDeviceIndices. -
pDeviceIndicesis a pointer to an array of device indices.
If deviceIndexCount is greater than zero, then on device index i
the buffer is attached to the instance of memory on the physical
device with device index pDeviceIndices[i].
If deviceIndexCount is zero and memory comes from a memory heap
with the VK_MEMORY_HEAP_MULTI_INSTANCE_BIT bit set, then it is as if
pDeviceIndices contains consecutive indices from zero to the number of
physical devices in the logical device, minus one.
In other words, by default each physical device attaches to its own instance
of memory.
If deviceIndexCount is zero and memory comes from a memory heap
without the VK_MEMORY_HEAP_MULTI_INSTANCE_BIT bit set, then it is as
if pDeviceIndices contains an array of zeros.
In other words, by default each physical device attaches to instance zero.
To attach memory to a VkImage object created without the
VK_IMAGE_CREATE_DISJOINT_BIT set, call:
VkResult vkBindImageMemory(
VkDevice device,
VkImage image,
VkDeviceMemory memory,
VkDeviceSize memoryOffset);
-
deviceis the logical device that owns the image and memory. -
imageis the image. -
memoryis theVkDeviceMemoryobject describing the device memory to attach. -
memoryOffsetis the start offset of the region ofmemorywhich is to be bound to the image. The number of bytes returned in theVkMemoryRequirements::sizemember inmemory, starting frommemoryOffsetbytes, will be bound to the specified image.
vkBindImageMemory is equivalent to passing the same parameters through
VkBindImageMemoryInfo to vkBindImageMemory2.
To attach memory to image objects for one or more images at a time, call:
VkResult vkBindImageMemory2(
VkDevice device,
uint32_t bindInfoCount,
const VkBindImageMemoryInfo* pBindInfos);
or the equivalent command
VkResult vkBindImageMemory2KHR(
VkDevice device,
uint32_t bindInfoCount,
const VkBindImageMemoryInfo* pBindInfos);
-
deviceis the logical device that owns the images and memory. -
bindInfoCountis the number of elements inpBindInfos. -
pBindInfosis a pointer to an array of structures of type VkBindImageMemoryInfo, describing images and memory to bind.
On some implementations, it may be more efficient to batch memory bindings into a single command.
VkBindImageMemoryInfo contains members corresponding to the parameters
of vkBindImageMemory.
The VkBindImageMemoryInfo structure is defined as:
typedef struct VkBindImageMemoryInfo {
VkStructureType sType;
const void* pNext;
VkImage image;
VkDeviceMemory memory;
VkDeviceSize memoryOffset;
} VkBindImageMemoryInfo;
or the equivalent
typedef VkBindImageMemoryInfo VkBindImageMemoryInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
imageis the image to be attached to memory. -
memoryis aVkDeviceMemoryobject describing the device memory to attach. -
memoryOffsetis the start offset of the region ofmemorywhich is to be bound to the image. The number of bytes returned in theVkMemoryRequirements::sizemember inmemory, starting frommemoryOffsetbytes, will be bound to the specified image.
typedef struct VkBindImageMemoryDeviceGroupInfo {
VkStructureType sType;
const void* pNext;
uint32_t deviceIndexCount;
const uint32_t* pDeviceIndices;
uint32_t splitInstanceBindRegionCount;
const VkRect2D* pSplitInstanceBindRegions;
} VkBindImageMemoryDeviceGroupInfo;
or the equivalent
typedef VkBindImageMemoryDeviceGroupInfo VkBindImageMemoryDeviceGroupInfoKHR;
If the pNext list of VkBindImageMemoryInfo includes a
VkBindImageMemoryDeviceGroupInfo structure, then that structure
determines how memory is bound to images across multiple devices in a device
group.
The VkBindImageMemoryDeviceGroupInfo structure is defined as:
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
deviceIndexCountis the number of elements inpDeviceIndices. -
pDeviceIndicesis a pointer to an array of device indices. -
splitInstanceBindRegionCountis the number of elements inpSplitInstanceBindRegions. -
pSplitInstanceBindRegionsis a pointer to an array of rectangles describing which regions of the image are attached to each instance of memory.
If deviceIndexCount is greater than zero, then on device index i
image is attached to the instance of the memory on the physical device
with device index pDeviceIndices[i].
Let N be the number of physical devices in the logical device.
If splitInstanceBindRegionCount is greater than zero, then
pSplitInstanceBindRegions is an array of N2 rectangles, where
the image region specified by the rectangle at element i*N+j in
resource instance i is bound to the memory instance j.
The blocks of the memory that are bound to each sparse image block region
use an offset in memory, relative to memoryOffset, computed as if the
whole image were being bound to a contiguous range of memory.
In other words, horizontally adjacent image blocks use consecutive blocks of
memory, vertically adjacent image blocks are separated by the number of
bytes per block multiplied by the width in blocks of image, and the
block at (0,0) corresponds to memory starting at memoryOffset.
If splitInstanceBindRegionCount and deviceIndexCount are zero
and the memory comes from a memory heap with the
VK_MEMORY_HEAP_MULTI_INSTANCE_BIT bit set, then it is as if
pDeviceIndices contains consecutive indices from zero to the number of
physical devices in the logical device, minus one.
In other words, by default each physical device attaches to its own instance
of the memory.
If splitInstanceBindRegionCount and deviceIndexCount are zero
and the memory comes from a memory heap without the
VK_MEMORY_HEAP_MULTI_INSTANCE_BIT bit set, then it is as if
pDeviceIndices contains an array of zeros.
In other words, by default each physical device attaches to instance zero.
If the pNext chain of VkBindImageMemoryInfo includes a
VkBindImageMemorySwapchainInfoKHR structure, then that structure
includes a swapchain handle and image index indicating that the image will
be bound to memory from that swapchain.
The VkBindImageMemorySwapchainInfoKHR structure is defined as:
typedef struct VkBindImageMemorySwapchainInfoKHR {
VkStructureType sType;
const void* pNext;
VkSwapchainKHR swapchain;
uint32_t imageIndex;
} VkBindImageMemorySwapchainInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
swapchainis VK_NULL_HANDLE or a swapchain handle. -
imageIndexis an image index withinswapchain.
If swapchain is not NULL, the swapchain and imageIndex
are used to determine the memory that the image is bound to, instead of
memory and memoryOffset.
Memory can be bound to a swapchain and use the pDeviceIndices or
pSplitInstanceBindRegions members of
VkBindImageMemoryDeviceGroupInfo.
In order to bind planes of a disjoint image, include a
VkBindImagePlaneMemoryInfo structure in the pNext chain of
VkBindImageMemoryInfo.
The VkBindImagePlaneMemoryInfo structure is defined as:
typedef struct VkBindImagePlaneMemoryInfo {
VkStructureType sType;
const void* pNext;
VkImageAspectFlagBits planeAspect;
} VkBindImagePlaneMemoryInfo;
or the equivalent
typedef VkBindImagePlaneMemoryInfo VkBindImagePlaneMemoryInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
planeAspectis the aspect of the disjoint image plane to bind.
There is an implementation-dependent limit, bufferImageGranularity,
which specifies a page-like granularity at which linear and non-linear
resources must be placed in adjacent memory locations to avoid aliasing.
Two resources which do not satisfy this granularity requirement are said to
alias.
bufferImageGranularity is specified in bytes, and must be a power of
two.
Implementations which do not impose a granularity restriction may report a
bufferImageGranularity value of one.
|
Note
Despite its name, |
Given resourceA at the lower memory offset and resourceB at the higher
memory offset in the same VkDeviceMemory object, where one resource is
linear and the other is non-linear (as defined in the
Glossary), and the following:
resourceA.end = resourceA.memoryOffset + resourceA.size - 1
resourceA.endPage = resourceA.end & ~(bufferImageGranularity-1)
resourceB.start = resourceB.memoryOffset
resourceB.startPage = resourceB.start & ~(bufferImageGranularity-1)
The following property must hold:
resourceA.endPage < resourceB.startPage
That is, the end of the first resource (A) and the beginning of the second
resource (B) must be on separate “pages” of size
bufferImageGranularity.
bufferImageGranularity may be different than the physical page size
of the memory heap.
This restriction is only needed when a linear resource and a non-linear
resource are adjacent in memory and will be used simultaneously.
The memory ranges of adjacent resources can be closer than
bufferImageGranularity, provided they meet the alignment
requirement for the objects in question.
Sparse block size in bytes and sparse image and buffer memory alignments
must all be multiples of the bufferImageGranularity.
Therefore, memory bound to sparse resources naturally satisfies the
bufferImageGranularity.
11.7. Resource Sharing Mode
Buffer and image objects are created with a sharing mode controlling how they can be accessed from queues. The supported sharing modes are:
typedef enum VkSharingMode {
VK_SHARING_MODE_EXCLUSIVE = 0,
VK_SHARING_MODE_CONCURRENT = 1,
} VkSharingMode;
-
VK_SHARING_MODE_EXCLUSIVEspecifies that access to any range or image subresource of the object will be exclusive to a single queue family at a time. -
VK_SHARING_MODE_CONCURRENTspecifies that concurrent access to any range or image subresource of the object from multiple queue families is supported.
|
Note
|
Ranges of buffers and image subresources of image objects created using
VK_SHARING_MODE_EXCLUSIVE must only be accessed by queues in the
queue family that has ownership of the resource.
Upon creation, such resources are not owned by any queue family; ownership
is implicitly acquired upon first use within a queue.
Once a resource using VK_SHARING_MODE_EXCLUSIVE is owned by some queue
family, the application must perform a
queue family ownership transfer to make
the memory contents of a range or image subresource accessible to a
different queue family.
|
Note
Images still require a layout transition from
|
A queue family can take ownership of an image subresource or buffer range
of a resource created with VK_SHARING_MODE_EXCLUSIVE, without an
ownership transfer, in the same way as for a resource that was just created;
however, taking ownership in this way has the effect that the contents of
the image subresource or buffer range are undefined.
Ranges of buffers and image subresources of image objects created using
VK_SHARING_MODE_CONCURRENT must only be accessed by queues from the
queue families specified through the queueFamilyIndexCount and
pQueueFamilyIndices members of the corresponding create info
structures.
11.7.1. External Resource Sharing
Resources should only be accessed in the Vulkan instance that has exclusive
ownership of their underlying memory.
Only one Vulkan instance has exclusive ownership of a resource’s underlying
memory at a given time, regardless of whether the resource was created using
VK_SHARING_MODE_EXCLUSIVE or VK_SHARING_MODE_CONCURRENT.
Applications can transfer ownership of a resource’s underlying memory only
if the memory has been imported from or exported to another instance or
external API using external memory handles.
The semantics for transferring ownership outside of the instance are similar
to those used for transferring ownership of VK_SHARING_MODE_EXCLUSIVE
resources between queues, and is also accomplished using
VkBufferMemoryBarrier or VkImageMemoryBarrier operations.
Applications must
-
Release exclusive ownership from the source instance or API.
-
Ensure the release operation has completed using semaphores or fences.
-
Acquire exclusive ownership in the destination instance or API
Unlike queue ownership transfers, the destination instance or API is not
specified explicitly when releasing ownership, nor is the source instance or
API specified when acquiring ownership.
Instead, the image or memory barrier’s dstQueueFamilyIndex or
srcQueueFamilyIndex parameters are set to the reserved queue family
index VK_QUEUE_FAMILY_EXTERNAL
or VK_QUEUE_FAMILY_FOREIGN_EXT
to represent the external destination or source respectively.
Binding a resource to a memory object shared between multiple Vulkan
instances or other APIs does not change the ownership of the underlying
memory.
The first entity to access the resource implicitly acquires ownership.
Accessing a resource backed by memory that is owned by a particular instance
or API has the same semantics as accessing a VK_SHARING_MODE_EXCLUSIVE
resource, with one exception: Implementations must ensure layout
transitions performed on one member of a set of identical subresources of
identical images that alias the same range of an underlying memory object
affect the layout of all the subresources in the set.
As a corollary, writes to any image subresources in such a set must not
make the contents of memory used by other subresources in the set undefined.
An application can define the content of a subresource of one image by
performing device writes to an identical subresource of another image
provided both images are bound to the same region of external memory.
Applications may also add resources to such a set after the content of the
existing set members has been defined without making the content undefined
by creating a new image with the initial layout
VK_IMAGE_LAYOUT_UNDEFINED and binding it to the same region of
external memory as the existing images.
|
Note
Because layout transitions apply to all identical images aliasing the same region of external memory, the actual layout of the memory backing a new image as well as an existing image with defined content will not be undefined. Such an image is not usable until it acquires ownership of its memory from the existing owner. Therefore, the layout specified as part of this transition will be the true initial layout of the image. The undefined layout specified when creating it is a placeholder to simplify valid usage requirements. |
11.8. Memory Aliasing
A range of a VkDeviceMemory allocation is aliased if it is bound to
multiple resources simultaneously, as described below, via
vkBindImageMemory, vkBindBufferMemory,
via sparse memory bindings, or by binding
the memory to resources in multiple Vulkan instances or external APIs using
external memory handle export and import mechanisms.
Consider two resources, resourceA and resourceB, bound respectively to
memory rangeA and rangeB.
Let paddedRangeA and paddedRangeB be, respectively, rangeA and
rangeB aligned to bufferImageGranularity.
If the resources are both linear or both non-linear (as defined in the
Glossary), then the resources alias the
memory in the intersection of rangeA and rangeB.
If one resource is linear and the other is non-linear, then the resources
alias the memory in the intersection of paddedRangeA and paddedRangeB.
Applications can alias memory, but use of multiple aliases is subject to several constraints.
|
Note
Memory aliasing can be useful to reduce the total device memory footprint of an application, if some large resources are used for disjoint periods of time. |
When an opaque, non-VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT image is
bound to an aliased range, all image subresources of the image overlap the
range.
When a linear image is bound to an aliased range, the image subresources
that (according to the image’s advertised layout) include bytes from the
aliased range overlap the range.
When a VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT image has sparse image
blocks bound to an aliased range, only image subresources including those
sparse image blocks overlap the range, and when the memory bound to the
image’s mip tail overlaps an aliased range all image subresources in the mip
tail overlap the range.
Buffers, and linear image subresources in either the
VK_IMAGE_LAYOUT_PREINITIALIZED or VK_IMAGE_LAYOUT_GENERAL
layouts, are host-accessible subresources.
That is, the host has a well-defined addressing scheme to interpret the
contents, and thus the layout of the data in memory can be consistently
interpreted across aliases if each of those aliases is a host-accessible
subresource.
Non-linear images, and linear image subresources in other layouts, are not
host-accessible.
If two aliases are both host-accessible, then they interpret the contents of the memory in consistent ways, and data written to one alias can be read by the other alias.
If two aliases are both images that were created with identical creation
parameters, both were created with the VK_IMAGE_CREATE_ALIAS_BIT flag
set, and both are bound identically to memory
except for VkBindImageMemoryDeviceGroupInfo::pDeviceIndices and
VkBindImageMemoryDeviceGroupInfo::pSplitInstanceBindRegions,
then they interpret the contents of the memory in consistent ways, and data
written to one alias can be read by the other alias.
Additionally, if an invididual plane of a multi-planar image and a single-plane image alias the same memory, then they also interpret the contents of the memory in consistent ways under the same conditions, but with the following modifications:
-
Both must have been created with the
VK_IMAGE_CREATE_DISJOINT_BITflag. -
The single-plane image must have an VkFormat that is equivalent to that of the multi-planar image’s individual plane.
-
The single-plane image and the individual plane of the multi-planar image must be bound identically to memory except for VkBindImageMemoryDeviceGroupInfo::
pDeviceIndicesand VkBindImageMemoryDeviceGroupInfo::pSplitInstanceBindRegions. -
The
widthandheightof the single-plane image are derived from the multi-planar image’s dimensions in the manner listed for plane compatibility for the aliased plane. -
All other creation parameters must be identical
Aliases created by binding the same memory to resources in multiple Vulkan instances or external APIs using external memory handle export and import mechanisms interpret the contents of the memory in consistent ways, and data written to one alias can be read by the other alias.
Otherwise, the aliases interpret the contents of the memory differently, and writes via one alias make the contents of memory partially or completely undefined to the other alias. If the first alias is a host-accessible subresource, then the bytes affected are those written by the memory operations according to its addressing scheme. If the first alias is not host-accessible, then the bytes affected are those overlapped by the image subresources that were written. If the second alias is a host-accessible subresource, the affected bytes become undefined. If the second alias is a not host-accessible, all sparse image blocks (for sparse partially-resident images) or all image subresources (for non-sparse image and fully resident sparse images) that overlap the affected bytes become undefined.
If any image subresources are made undefined due to writes to an alias, then
each of those image subresources must have its layout transitioned from
VK_IMAGE_LAYOUT_UNDEFINED to a valid layout before it is used, or from
VK_IMAGE_LAYOUT_PREINITIALIZED if the memory has been written by the
host.
If any sparse blocks of a sparse image have been made undefined, then only
the image subresources containing them must be transitioned.
Use of an overlapping range by two aliases must be separated by a memory dependency using the appropriate access types if at least one of those uses performs writes, whether the aliases interpret memory consistently or not. If buffer or image memory barriers are used, the scope of the barrier must contain the entire range and/or set of image subresources that overlap.
If two aliasing image views are used in the same framebuffer, then the
render pass must declare the attachments using the
VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT, and
follow the other rules listed in that section.
Access to resources which alias memory from shaders using variables
decorated with Coherent are not automatically coherent with each other.
|
Note
Memory recycled via an application suballocator (i.e. without freeing and reallocating the memory objects) is not substantially different from memory aliasing. However, a suballocator usually waits on a fence before recycling a region of memory, and signaling a fence involves sufficient implicit dependencies to satisfy all the above requirements. |
12. Samplers
VkSampler objects represent the state of an image sampler which is
used by the implementation to read image data and apply filtering and other
transformations for the shader.
Samplers are represented by VkSampler handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkSampler)
To create a sampler object, call:
VkResult vkCreateSampler(
VkDevice device,
const VkSamplerCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkSampler* pSampler);
-
deviceis the logical device that creates the sampler. -
pCreateInfois a pointer to an instance of the VkSamplerCreateInfo structure specifying the state of the sampler object. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pSamplerpoints to a VkSampler handle in which the resulting sampler object is returned.
The VkSamplerCreateInfo structure is defined as:
typedef struct VkSamplerCreateInfo {
VkStructureType sType;
const void* pNext;
VkSamplerCreateFlags flags;
VkFilter magFilter;
VkFilter minFilter;
VkSamplerMipmapMode mipmapMode;
VkSamplerAddressMode addressModeU;
VkSamplerAddressMode addressModeV;
VkSamplerAddressMode addressModeW;
float mipLodBias;
VkBool32 anisotropyEnable;
float maxAnisotropy;
VkBool32 compareEnable;
VkCompareOp compareOp;
float minLod;
float maxLod;
VkBorderColor borderColor;
VkBool32 unnormalizedCoordinates;
} VkSamplerCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
magFilteris a VkFilter value specifying the magnification filter to apply to lookups. -
minFilteris a VkFilter value specifying the minification filter to apply to lookups. -
mipmapModeis a VkSamplerMipmapMode value specifying the mipmap filter to apply to lookups. -
addressModeUis a VkSamplerAddressMode value specifying the addressing mode for outside [0..1] range for U coordinate. -
addressModeVis a VkSamplerAddressMode value specifying the addressing mode for outside [0..1] range for V coordinate. -
addressModeWis a VkSamplerAddressMode value specifying the addressing mode for outside [0..1] range for W coordinate. -
mipLodBiasis the bias to be added to mipmap LOD (level-of-detail) calculation and bias provided by image sampling functions in SPIR-V, as described in the Level-of-Detail Operation section. -
anisotropyEnableisVK_TRUEto enable anisotropic filtering, as described in the Texel Anisotropic Filtering section, orVK_FALSEotherwise. -
maxAnisotropyis the anisotropy value clamp used by the sampler whenanisotropyEnableisVK_TRUE. IfanisotropyEnableisVK_FALSE,maxAnisotropyis ignored. -
compareEnableisVK_TRUEto enable comparison against a reference value during lookups, orVK_FALSEotherwise.-
Note: Some implementations will default to shader state if this member does not match.
-
-
compareOpis a VkCompareOp value specifying the comparison function to apply to fetched data before filtering as described in the Depth Compare Operation section. -
minLodandmaxLodare the values used to clamp the computed LOD value, as described in the Level-of-Detail Operation section.maxLodmust be greater than or equal tominLod. -
borderColoris a VkBorderColor value specifying the predefined border color to use. -
unnormalizedCoordinatescontrols whether to use unnormalized or normalized texel coordinates to address texels of the image. When set toVK_TRUE, the range of the image coordinates used to lookup the texel is in the range of zero to the image dimensions for x, y and z. When set toVK_FALSEthe range of image coordinates is zero to one. WhenunnormalizedCoordinatesisVK_TRUE, samplers have the following requirements:-
minFilterandmagFiltermust be equal. -
mipmapModemust beVK_SAMPLER_MIPMAP_MODE_NEAREST. -
minLodandmaxLodmust be zero. -
addressModeUandaddressModeVmust each be eitherVK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGEorVK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER. -
anisotropyEnablemust beVK_FALSE. -
compareEnablemust beVK_FALSE. -
The sampler must not enable sampler Y’CBCR conversion.
-
-
When
unnormalizedCoordinatesisVK_TRUE, images the sampler is used with in the shader have the following requirements:-
The
viewTypemust be eitherVK_IMAGE_VIEW_TYPE_1DorVK_IMAGE_VIEW_TYPE_2D. -
The image view must have a single layer and a single mip level.
-
-
When
unnormalizedCoordinatesisVK_TRUE, image built-in functions in the shader that use the sampler have the following requirements:-
The functions must not use projection.
-
The functions must not use offsets.
-
|
Mapping of OpenGL to Vulkan filter modes
There are no Vulkan filter modes that directly correspond to OpenGL
minification filters of Note that using a |
The maximum number of sampler objects which can be simultaneously created
on a device is implementation-dependent and specified by the
maxSamplerAllocationCount
member of the VkPhysicalDeviceLimits structure.
If maxSamplerAllocationCount is exceeded, vkCreateSampler will
return VK_ERROR_TOO_MANY_OBJECTS.
Since VkSampler is a non-dispatchable handle type, implementations
may return the same handle for sampler state vectors that are identical.
In such cases, all such objects would only count once against the
maxSamplerAllocationCount limit.
typedef VkFlags VkSamplerCreateFlags;
VkSamplerCreateFlags is a bitmask type for setting a mask, but is
currently reserved for future use.
If the pNext chain of VkSamplerCreateInfo includes a
VkSamplerReductionModeCreateInfoEXT structure, then that structure
includes a mode that controls how texture filtering combines texel values.
The VkSamplerReductionModeCreateInfoEXT structure is defined as:
typedef struct VkSamplerReductionModeCreateInfoEXT {
VkStructureType sType;
const void* pNext;
VkSamplerReductionModeEXT reductionMode;
} VkSamplerReductionModeCreateInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
reductionModeis an enum of type VkSamplerReductionModeEXT that controls how texture filtering combines texel values.
If this structure is not present, reductionMode is considered to be
VK_SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE_EXT.
Reduction modes are specified by VkSamplerReductionModeEXT, which takes values:
typedef enum VkSamplerReductionModeEXT {
VK_SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE_EXT = 0,
VK_SAMPLER_REDUCTION_MODE_MIN_EXT = 1,
VK_SAMPLER_REDUCTION_MODE_MAX_EXT = 2,
} VkSamplerReductionModeEXT;
-
VK_SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE_EXTspecifies that texel values are combined by computing a weighted average of values in the footprint, using weights as specified in the image operations chapter. -
VK_SAMPLER_REDUCTION_MODE_MIN_EXTspecifies that texel values are combined by taking the component-wise minimum of values in the footprint with non-zero weights. -
VK_SAMPLER_REDUCTION_MODE_MAX_EXTspecifies that texel values are combined by taking the component-wise maximum of values in the footprint with non-zero weights.
Possible values of the VkSamplerCreateInfo::magFilter and
minFilter parameters, specifying filters used for texture lookups,
are:
typedef enum VkFilter {
VK_FILTER_NEAREST = 0,
VK_FILTER_LINEAR = 1,
VK_FILTER_CUBIC_IMG = 1000015000,
} VkFilter;
-
VK_FILTER_NEARESTspecifies nearest filtering. -
VK_FILTER_LINEARspecifies linear filtering. -
VK_FILTER_CUBIC_IMGspecifies cubic filtering.
These filters are described in detail in Texel Filtering.
Possible values of the VkSamplerCreateInfo::mipmapMode,
specifying the mipmap mode used for texture lookups, are:
typedef enum VkSamplerMipmapMode {
VK_SAMPLER_MIPMAP_MODE_NEAREST = 0,
VK_SAMPLER_MIPMAP_MODE_LINEAR = 1,
} VkSamplerMipmapMode;
-
VK_SAMPLER_MIPMAP_MODE_NEARESTspecifies nearest filtering. -
VK_SAMPLER_MIPMAP_MODE_LINEARspecifies linear filtering.
These modes are described in detail in Texel Filtering.
Possible values of the VkSamplerCreateInfo::addressMode*
parameters, specifying the behavior of sampling with coordinates outside the
range [0,1] for the respective u, v, or w coordinate
as defined in the Wrapping Operation
section, are:
typedef enum VkSamplerAddressMode {
VK_SAMPLER_ADDRESS_MODE_REPEAT = 0,
VK_SAMPLER_ADDRESS_MODE_MIRRORED_REPEAT = 1,
VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE = 2,
VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER = 3,
VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE = 4,
} VkSamplerAddressMode;
-
VK_SAMPLER_ADDRESS_MODE_REPEATspecifies that the repeat wrap mode will be used. -
VK_SAMPLER_ADDRESS_MODE_MIRRORED_REPEATspecifies that the mirrored repeat wrap mode will be used. -
VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGEspecifies that the clamp to edge wrap mode will be used. -
VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDERspecifies that the clamp to border wrap mode will be used. -
VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGEspecifies that the mirror clamp to edge wrap mode will be used. This is only valid if theVK_KHR_sampler_mirror_clamp_to_edgeextension is enabled.
Possible values of VkSamplerCreateInfo::borderColor, specifying
the border color used for texture lookups, are:
typedef enum VkBorderColor {
VK_BORDER_COLOR_FLOAT_TRANSPARENT_BLACK = 0,
VK_BORDER_COLOR_INT_TRANSPARENT_BLACK = 1,
VK_BORDER_COLOR_FLOAT_OPAQUE_BLACK = 2,
VK_BORDER_COLOR_INT_OPAQUE_BLACK = 3,
VK_BORDER_COLOR_FLOAT_OPAQUE_WHITE = 4,
VK_BORDER_COLOR_INT_OPAQUE_WHITE = 5,
} VkBorderColor;
-
VK_BORDER_COLOR_FLOAT_TRANSPARENT_BLACKspecifies a transparent, floating-point format, black color. -
VK_BORDER_COLOR_INT_TRANSPARENT_BLACKspecifies a transparent, integer format, black color. -
VK_BORDER_COLOR_FLOAT_OPAQUE_BLACKspecifies an opaque, floating-point format, black color. -
VK_BORDER_COLOR_INT_OPAQUE_BLACKspecifies an opaque, integer format, black color. -
VK_BORDER_COLOR_FLOAT_OPAQUE_WHITEspecifies an opaque, floating-point format, white color. -
VK_BORDER_COLOR_INT_OPAQUE_WHITEspecifies an opaque, integer format, white color.
These colors are described in detail in Texel Replacement.
To destroy a sampler, call:
void vkDestroySampler(
VkDevice device,
VkSampler sampler,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the sampler. -
sampleris the sampler to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
12.1. Sampler Y’CBCR conversion
To create a sampler with Y’CBCR conversion enabled, add a
VkSamplerYcbcrConversionInfo to the pNext chain of the
VkSamplerCreateInfo structure.
To create a sampler Y’CBCR conversion, the
samplerYcbcrConversion
feature must be enabled.
Conversion must be fixed at pipeline creation time, through use of a
combined image sampler with an immutable sampler in
VkDescriptorSetLayoutBinding.
A VkSamplerYcbcrConversionInfo must be provided for samplers to be
used with image views that access VK_IMAGE_ASPECT_COLOR_BIT if the
format appears in Formats requiring sampler Y’CBCR conversion for VK_IMAGE_ASPECT_COLOR_BIT image views
, or if the image view has an
external format
.
The VkSamplerYcbcrConversionInfo structure is defined as:
typedef struct VkSamplerYcbcrConversionInfo {
VkStructureType sType;
const void* pNext;
VkSamplerYcbcrConversion conversion;
} VkSamplerYcbcrConversionInfo;
or the equivalent
typedef VkSamplerYcbcrConversionInfo VkSamplerYcbcrConversionInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
conversionis a VkSamplerYcbcrConversion handle created with vkCreateSamplerYcbcrConversion.
A sampler Y’CBCR conversion is an opaque representation of a
device-specific sampler Y’CBCR conversion description, represented as a
VkSamplerYcbcrConversion handle:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkSamplerYcbcrConversion)
or the equivalent
typedef VkSamplerYcbcrConversion VkSamplerYcbcrConversionKHR;
To create a VkSamplerYcbcrConversion, call:
VkResult vkCreateSamplerYcbcrConversion(
VkDevice device,
const VkSamplerYcbcrConversionCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkSamplerYcbcrConversion* pYcbcrConversion);
or the equivalent command
VkResult vkCreateSamplerYcbcrConversionKHR(
VkDevice device,
const VkSamplerYcbcrConversionCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkSamplerYcbcrConversion* pYcbcrConversion);
-
deviceis the logical device that creates the sampler Y’CBCR conversion. -
pCreateInfois a pointer to an instance of the VkSamplerYcbcrConversionCreateInfo specifying the requested sampler Y’CBCR conversion. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pYcbcrConversionpoints to a VkSamplerYcbcrConversion handle in which the resulting sampler Y’CBCR conversion is returned.
The interpretation of the configured sampler Y’CBCR conversion is described in more detail in the description of sampler Y’CBCR conversion in the Image Operations chapter.
The VkSamplerYcbcrConversionCreateInfo structure is defined as:
typedef struct VkSamplerYcbcrConversionCreateInfo {
VkStructureType sType;
const void* pNext;
VkFormat format;
VkSamplerYcbcrModelConversion ycbcrModel;
VkSamplerYcbcrRange ycbcrRange;
VkComponentMapping components;
VkChromaLocation xChromaOffset;
VkChromaLocation yChromaOffset;
VkFilter chromaFilter;
VkBool32 forceExplicitReconstruction;
} VkSamplerYcbcrConversionCreateInfo;
or the equivalent
typedef VkSamplerYcbcrConversionCreateInfo VkSamplerYcbcrConversionCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
formatis the format of the image from which color information will be retrieved. -
ycbcrModeldescribes the color matrix for conversion between color models. -
ycbcrRangedescribes whether the encoded values have headroom and foot room, or whether the encoding uses the full numerical range. -
componentsapplies a swizzle based on VkComponentSwizzle enums prior to range expansion and color model conversion. -
xChromaOffsetdescribes the sample location associated with downsampled chroma channels in the x dimension.xChromaOffsethas no effect for formats in which chroma channels are the same resolution as the luma channel. -
yChromaOffsetdescribes the sample location associated with downsampled chroma channels in the y dimension.yChromaOffsethas no effect for formats in which the chroma channels are not downsampled vertically. -
chromaFilteris the filter for chroma reconstruction. -
forceExplicitReconstructioncan be used to ensure that reconstruction is done explicitly, if supported.
|
Note
Setting |
If the pNext chain has an instance of VkExternalFormatANDROID
with non-zero externalFormat member, the sampler Y’CBCR conversion
object represents an external format conversion, and format must be
VK_FORMAT_UNDEFINED.
Such conversions must only be used to sample image views with a matching
external
format.
When creating an external format conversion, the value of components
is ignored.
If chromaFilter is VK_FILTER_NEAREST, chroma samples are
reconstructed to luma channel resolution using nearest-neighbour sampling.
Otherwise, chroma samples are reconstructed using interpolation.
More details can be found in the
description of sampler Y’CBCR conversion in the Image
Operations chapter.
VkSamplerYcbcrModelConversion defines the conversion from the source color model to the shader color model. Possible values are:
typedef enum VkSamplerYcbcrModelConversion {
VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY = 0,
VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY = 1,
VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_709 = 2,
VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_601 = 3,
VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_2020 = 4,
VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY_KHR = VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY,
VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY_KHR = VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY,
VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_709_KHR = VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_709,
VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_601_KHR = VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_601,
VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_2020_KHR = VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_2020,
} VkSamplerYcbcrModelConversion;
or the equivalent
typedef VkSamplerYcbcrModelConversion VkSamplerYcbcrModelConversionKHR;
-
VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITYspecifies that the input values to the conversion are unmodified. -
VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITYspecifies no model conversion but the inputs are range expanded as for Y’CBCR. -
VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_709specifies the color model conversion from Y’CBCR to R’G’B' defined in BT.709 and described in the “BT.709 Y’CBCR conversion” section of the Khronos Data Format Specification. -
VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_601specifies the color model conversion from Y’CBCR to R’G’B' defined in BT.601 and described in the “BT.601 Y’CBCR conversion” section of the Khronos Data Format Specification. -
VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_2020specifies the color model conversion from Y’CBCR to R’G’B' defined in BT.2020 and described in the “BT.2020 Y’CBCR conversion” section of the Khronos Data Format Specification.
In the VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_* color models, for the
input to the sampler Y’CBCR range expansion and model conversion:
-
the Y (Y' luma) channel corresponds to the G channel of an RGB image.
-
the CB (CB or “U” blue color difference) channel corresponds to the B channel of an RGB image.
-
the CR (CR or “V” red color difference) channel corresponds to the R channel of an RGB image.
-
the alpha channel, if present, is not modified by color model conversion.
These rules reflect the mapping of channels after the channel swizzle
operation (controlled by
VkSamplerYcbcrConversionCreateInfo::components).
|
Note
For example, an “YUVA” 32-bit format comprising four 8-bit channels can be
implemented as
|
The VkSamplerYcbcrRange enum describes whether color channels are encoded using the full range of numerical values or whether values are reserved for headroom and foot room. VkSamplerYcbcrRange is defined as:
typedef enum VkSamplerYcbcrRange {
VK_SAMPLER_YCBCR_RANGE_ITU_FULL = 0,
VK_SAMPLER_YCBCR_RANGE_ITU_NARROW = 1,
VK_SAMPLER_YCBCR_RANGE_ITU_FULL_KHR = VK_SAMPLER_YCBCR_RANGE_ITU_FULL,
VK_SAMPLER_YCBCR_RANGE_ITU_NARROW_KHR = VK_SAMPLER_YCBCR_RANGE_ITU_NARROW,
} VkSamplerYcbcrRange;
or the equivalent
typedef VkSamplerYcbcrRange VkSamplerYcbcrRangeKHR;
-
VK_SAMPLER_YCBCR_RANGE_ITU_FULLspecifies that the full range of the encoded values are valid and interpreted according to the ITU “full range” quantization rules. -
VK_SAMPLER_YCBCR_RANGE_ITU_NARROWspecifies that headroom and foot room are reserved in the numerical range of encoded values, and the remaining values are expanded according to the ITU “narrow range” quantization rules.
The formulae for these conversions is described in the Sampler Y’CBCR Range Expansion section of the Image Operations chapter.
No range modification takes place if ycbcrModel is
VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY; the ycbcrRange
field of VkSamplerYcbcrConversionCreateInfo is ignored in this case.
The VkChromaLocation enum, which defines the location of downsampled chroma channel samples relative to the luma samples, is defined as:
typedef enum VkChromaLocation {
VK_CHROMA_LOCATION_COSITED_EVEN = 0,
VK_CHROMA_LOCATION_MIDPOINT = 1,
VK_CHROMA_LOCATION_COSITED_EVEN_KHR = VK_CHROMA_LOCATION_COSITED_EVEN,
VK_CHROMA_LOCATION_MIDPOINT_KHR = VK_CHROMA_LOCATION_MIDPOINT,
} VkChromaLocation;
or the equivalent
typedef VkChromaLocation VkChromaLocationKHR;
-
VK_CHROMA_LOCATION_COSITED_EVENspecifies that downsampled chroma samples are aligned with luma samples with even coordinates. -
VK_CHROMA_LOCATION_MIDPOINTspecifies that downsampled chroma samples are located half way between each even luma sample and the nearest higher odd luma sample.
To destroy a sampler Y’CBCR conversion, call:
void vkDestroySamplerYcbcrConversion(
VkDevice device,
VkSamplerYcbcrConversion ycbcrConversion,
const VkAllocationCallbacks* pAllocator);
or the equivalent command
void vkDestroySamplerYcbcrConversionKHR(
VkDevice device,
VkSamplerYcbcrConversion ycbcrConversion,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the Y’CBCR conversion. -
ycbcrConversionis the conversion to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
13. Resource Descriptors
A descriptor is an opaque data structure representing a shader resource
such as a buffer, buffer view, image view, sampler, or combined image
sampler.
Descriptors are organised into descriptor sets, which are bound during
command recording for use in subsequent draw commands.
The arrangement of content in each descriptor set is determined by a
descriptor set layout, which determines what descriptors can be stored
within it.
The sequence of descriptor set layouts that can be used by a pipeline is
specified in a pipeline layout.
Each pipeline object can use up to maxBoundDescriptorSets (see
Limits) descriptor sets.
Shaders access resources via variables decorated with a descriptor set and binding number that link them to a descriptor in a descriptor set. The shader interface mapping to bound descriptor sets is described in the Shader Resource Interface section.
13.1. Descriptor Types
There are a number of different types of descriptor supported by Vulkan, corresponding to different resources or usage. The following sections describe the API definitions of each descriptor type. The mapping of each type to SPIR-V is listed in the Shader Resource and Descriptor Type Correspondence and Shader Resource and Storage Class Correspondence tables in the Shader Interfaces chapter.
13.1.1. Storage Image
A storage image (VK_DESCRIPTOR_TYPE_STORAGE_IMAGE) is a descriptor
type associated with an image resource via an
image view that load, store, and atomic
operations can be performed on.
Storage image loads are supported in all shader stages for image formats
which report support for the
VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT
feature bit via vkGetPhysicalDeviceFormatProperties in
VkFormatProperties::linearTilingFeatures (for images with linear
tiling) or VkFormatProperties::optimalTilingFeatures (for images
with optimal tiling).
Stores to storage images are supported in compute shaders for image formats
which report support for the VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT
feature via vkGetPhysicalDeviceFormatProperties in
VkFormatProperties::linearTilingFeatures (for images with linear
tiling) or VkFormatProperties::optimalTilingFeatures (for images
with optimal tiling).
Atomic operations on storage images are supported in compute shaders for
image formats which report support for the
VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT
feature via vkGetPhysicalDeviceFormatProperties in
VkFormatProperties::linearTilingFeatures (for images with linear
tiling) or VkFormatProperties::optimalTilingFeatures (for images
with optimal tiling).
When the fragmentStoresAndAtomics feature is enabled, stores and atomic
operations are also supported for storage images in fragment shaders with
the same set of image formats as supported in compute shaders.
When the vertexPipelineStoresAndAtomics feature is enabled, stores and atomic
operations are also supported in vertex, tessellation, and geometry shaders
with the same set of image formats as supported in compute shaders.
The image subresources for a storage image must be in the
VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR or
VK_IMAGE_LAYOUT_GENERAL layout in order to access its data in a
shader.
13.1.2. Sampler
A sampler descriptor (VK_DESCRIPTOR_TYPE_SAMPLER) is a descriptor
type associated with a sampler object, used to control the
behaviour of sampling operations performed on a
sampled image.
13.1.3. Sampled Image
A sampled image (VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE) is a descriptor
type associated with an image resource via an
image view that sampling operations
can be performed on.
Shaders combine a sampled image variable and a sampler variable to perform sampling operations.
Sampled images are supported in all shader stages for image formats which
report support for the
VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT
feature bit via vkGetPhysicalDeviceFormatProperties in
VkFormatProperties::linearTilingFeatures (for images with linear
tiling) or VkFormatProperties::optimalTilingFeatures (for images
with optimal tiling).
The image subresources for a sampled image must be in the
VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR,
VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL,
VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL,
VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL,
VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL, or
VK_IMAGE_LAYOUT_GENERAL layout in order to access its data in a
shader.
13.1.4. Combined Image Sampler
A combined image sampler (VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER)
is a single descriptor type associated with both a sampler and
an image resource, combining both a
sampler and sampled image descriptor into a single descriptor.
If the descriptor refers to a sampler that performs Y’CBCR conversion, the sampler must only be used to sample the image in the same descriptor. Otherwise, the sampler and image in this type of descriptor can be used freely with any other samplers and images.
The image subresources for a combined image sampler must be in the
VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR,
VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL,
VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL,
VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL,
VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL, or
VK_IMAGE_LAYOUT_GENERAL layout in order to access its data in a
shader.
|
Note
On some implementations, it may be more efficient to sample from an image using a combination of sampler and sampled image that are stored together in the descriptor set in a combined descriptor. |
13.1.5. Uniform Texel Buffer
A uniform texel buffer (VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER) is
a descriptor type associated with a buffer resource
via a buffer view that formatted load
operations can be performed on.
Uniform texel buffers define a tightly-packed 1-dimensional linear array of texels, with texels going through format conversion when read in a shader in the same way as they are for an image.
Load operations from uniform texel buffers are supported in all shader
stages for image formats which report support for the
VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BIT
feature bit via vkGetPhysicalDeviceFormatProperties in
VkFormatProperties::bufferFeatures.
13.1.6. Storage Texel Buffer
A storage texel buffer (VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER) is
a descriptor type associated with a buffer resource
via a buffer view that formatted
load, store, and atomic operations can be performed on.
Storage texel buffers define a tightly-packed 1-dimensional linear array of texels, with texels going through format conversion when read in a shader in the same way as they are for an image. Unlike uniform texel buffers, these buffers can also be written to in the same way as for storage images.
Storage texel buffer loads are supported in all shader stages for texel
buffer formats which report support for the
VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT
feature bit via vkGetPhysicalDeviceFormatProperties in
VkFormatProperties::bufferFeatures.
Stores to storage texel buffers are supported in compute shaders for texel
buffer formats which report support for the
VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT feature via
vkGetPhysicalDeviceFormatProperties in
VkFormatProperties::bufferFeatures.
Atomic operations on storage texel buffers are supported in compute shaders
for texel buffer formats which report support for the
VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_ATOMIC_BIT
feature via vkGetPhysicalDeviceFormatProperties in
VkFormatProperties::bufferFeatures.
When the fragmentStoresAndAtomics feature is enabled, stores and atomic
operations are also supported for storage texel buffers in fragment shaders
with the same set of texel buffer formats as supported in compute shaders.
When the vertexPipelineStoresAndAtomics feature is enabled, stores and atomic
operations are also supported in vertex, tessellation, and geometry shaders
with the same set of texel buffer formats as supported in compute shaders.
13.1.7. Storage Buffer
A storage buffer (VK_DESCRIPTOR_TYPE_STORAGE_BUFFER) is a descriptor
type associated with a buffer resource directly,
described in a shader as a structure with various members that load, store,
and atomic operations can be performed on.
|
Note
Atomic operations can only be performed on members of certain types as defined in the SPIR-V environment appendix. |
13.1.8. Uniform Buffer
A uniform buffer (VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER) is a descriptor
type associated with a buffer resource directly,
described in a shader as a structure with various members that load
operations can be performed on.
13.1.9. Dynamic Uniform Buffer
A dynamic uniform buffer (VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC)
is almost identical to a uniform buffer,
and differs only in how the offset into the buffer is specified.
The base offset calculated by the VkDescriptorBufferInfo when
initially updating the descriptor set is added
to a dynamic offset when binding
the descriptor set.
13.1.10. Dynamic Storage Buffer
A dynamic storage buffer (VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC)
is almost identical to a storage buffer,
and differs only in how the offset into the buffer is specified.
The base offset calculated by the VkDescriptorBufferInfo when
initially updating the descriptor set is added
to a dynamic offset when binding
the descriptor set.
13.1.11. Input Attachment
An input attachment (VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT) is a
descriptor type associated with an image resource via
an image view that can be used for
framebuffer local load operations in
fragment shaders.
All image formats that are supported for color attachments
(VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT) or depth/stencil attachments
(VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT) for a given image
tiling mode are also supported for input attachments.
The image subresources for an input attachment must be in the
VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR,
VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL,
VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL,
VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL,
VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL, or
VK_IMAGE_LAYOUT_GENERAL layout in order to access its data in a
shader.
13.2. Descriptor Sets
Descriptors are grouped together into descriptor set objects. A descriptor set object is an opaque object that contains storage for a set of descriptors, where the types and number of descriptors is defined by a descriptor set layout. The layout object may be used to define the association of each descriptor binding with memory or other implementation resources. The layout is used both for determining the resources that need to be associated with the descriptor set, and determining the interface between shader stages and shader resources.
13.2.1. Descriptor Set Layout
A descriptor set layout object is defined by an array of zero or more descriptor bindings. Each individual descriptor binding is specified by a descriptor type, a count (array size) of the number of descriptors in the binding, a set of shader stages that can access the binding, and (if using immutable samplers) an array of sampler descriptors.
Descriptor set layout objects are represented by VkDescriptorSetLayout
handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDescriptorSetLayout)
To create descriptor set layout objects, call:
VkResult vkCreateDescriptorSetLayout(
VkDevice device,
const VkDescriptorSetLayoutCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkDescriptorSetLayout* pSetLayout);
-
deviceis the logical device that creates the descriptor set layout. -
pCreateInfois a pointer to an instance of the VkDescriptorSetLayoutCreateInfo structure specifying the state of the descriptor set layout object. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pSetLayoutpoints to aVkDescriptorSetLayouthandle in which the resulting descriptor set layout object is returned.
Information about the descriptor set layout is passed in an instance of the
VkDescriptorSetLayoutCreateInfo structure:
typedef struct VkDescriptorSetLayoutCreateInfo {
VkStructureType sType;
const void* pNext;
VkDescriptorSetLayoutCreateFlags flags;
uint32_t bindingCount;
const VkDescriptorSetLayoutBinding* pBindings;
} VkDescriptorSetLayoutCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis a bitmask of VkDescriptorSetLayoutCreateFlagBits specifying options for descriptor set layout creation. -
bindingCountis the number of elements inpBindings. -
pBindingsis a pointer to an array of VkDescriptorSetLayoutBinding structures.
Bits which can be set in VkDescriptorSetLayoutCreateInfo::flags
to specify options for descriptor set layout are:
typedef enum VkDescriptorSetLayoutCreateFlagBits {
VK_DESCRIPTOR_SET_LAYOUT_CREATE_PUSH_DESCRIPTOR_BIT_KHR = 0x00000001,
VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXT = 0x00000002,
} VkDescriptorSetLayoutCreateFlagBits;
-
VK_DESCRIPTOR_SET_LAYOUT_CREATE_PUSH_DESCRIPTOR_BIT_KHRspecifies that descriptor sets must not be allocated using this layout, and descriptors are instead pushed by vkCmdPushDescriptorSetKHR. -
VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTspecifies that descriptor sets using this layout must be allocated from a descriptor pool created with theVK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT_EXTbit set. Descriptor set layouts created with this bit set have alternate limits for the maximum number of descriptors per-stage and per-pipeline layout. The non-UpdateAfterBind limits only count descriptors in sets created without this flag. The UpdateAfterBind limits count all descriptors, but the limits may be higher than the non-UpdateAfterBind limits.
typedef VkFlags VkDescriptorSetLayoutCreateFlags;
VkDescriptorSetLayoutCreateFlags is a bitmask type for setting a mask
of zero or more VkDescriptorSetLayoutCreateFlagBits.
The VkDescriptorSetLayoutBinding structure is defined as:
typedef struct VkDescriptorSetLayoutBinding {
uint32_t binding;
VkDescriptorType descriptorType;
uint32_t descriptorCount;
VkShaderStageFlags stageFlags;
const VkSampler* pImmutableSamplers;
} VkDescriptorSetLayoutBinding;
-
bindingis the binding number of this entry and corresponds to a resource of the same binding number in the shader stages. -
descriptorTypeis a VkDescriptorType specifying which type of resource descriptors are used for this binding. -
descriptorCountis the number of descriptors contained in the binding, accessed in a shader as an array. IfdescriptorCountis zero this binding entry is reserved and the resource must not be accessed from any stage via this binding within any pipeline using the set layout. -
stageFlagsmember is a bitmask of VkShaderStageFlagBits specifying which pipeline shader stages can access a resource for this binding.VK_SHADER_STAGE_ALLis a shorthand specifying that all defined shader stages, including any additional stages defined by extensions, can access the resource.If a shader stage is not included in
stageFlags, then a resource must not be accessed from that stage via this binding within any pipeline using the set layout. Other than input attachments which are limited to the fragment shader, there are no limitations on what combinations of stages can use a descriptor binding, and in particular a binding can be used by both graphics stages and the compute stage. -
pImmutableSamplersaffects initialization of samplers. IfdescriptorTypespecifies aVK_DESCRIPTOR_TYPE_SAMPLERorVK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLERtype descriptor, thenpImmutableSamplerscan be used to initialize a set of immutable samplers. Immutable samplers are permanently bound into the set layout; later binding a sampler into an immutable sampler slot in a descriptor set is not allowed. IfpImmutableSamplersis notNULL, then it is considered to be a pointer to an array of sampler handles that will be consumed by the set layout and used for the corresponding binding. IfpImmutableSamplersisNULL, then the sampler slots are dynamic and sampler handles must be bound into descriptor sets using this layout. IfdescriptorTypeis not one of these descriptor types, thenpImmutableSamplersis ignored.
The above layout definition allows the descriptor bindings to be specified
sparsely such that not all binding numbers between 0 and the maximum binding
number need to be specified in the pBindings array.
Bindings that are not specified have a descriptorCount and
stageFlags of zero, and the descriptorType is treated as
undefined.
However, all binding numbers between 0 and the maximum binding number in the
VkDescriptorSetLayoutCreateInfo::pBindings array may consume
memory in the descriptor set layout even if not all descriptor bindings are
used, though it should not consume additional memory from the descriptor
pool.
|
Note
The maximum binding number specified should be as compact as possible to avoid wasted memory. |
If the pNext chain of a VkDescriptorSetLayoutCreateInfo
structure includes a VkDescriptorSetLayoutBindingFlagsCreateInfoEXT
structure, then that structure includes an array of flags, one for each
descriptor set layout binding.
The VkDescriptorSetLayoutBindingFlagsCreateInfoEXT structure is defined as:
typedef struct VkDescriptorSetLayoutBindingFlagsCreateInfoEXT {
VkStructureType sType;
const void* pNext;
uint32_t bindingCount;
const VkDescriptorBindingFlagsEXT* pBindingFlags;
} VkDescriptorSetLayoutBindingFlagsCreateInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
bindingCountis zero or the number of elements inpBindingFlags. -
pBindingFlagsis a pointer to an array of VkDescriptorBindingFlagsEXT bitfields, one for each descriptor set layout binding.
If bindingCount is zero or if this structure is not in the pNext
chain, the VkDescriptorBindingFlagsEXT for each descriptor set layout
binding is considered to be zero.
Otherwise, the descriptor set layout binding at
VkDescriptorSetLayoutCreateInfo::pBindings[i] uses the flags in
pBindingFlags[i].
Bits which can be set in each element of
VkDescriptorSetLayoutBindingFlagsCreateInfoEXT::pBindingFlags to
specify options for the corresponding descriptor set layout binding are:
typedef enum VkDescriptorBindingFlagBitsEXT {
VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT_EXT = 0x00000001,
VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT_EXT = 0x00000002,
VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT_EXT = 0x00000004,
VK_DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT_EXT = 0x00000008,
} VkDescriptorBindingFlagBitsEXT;
-
VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT_EXTindicates that if descriptors in this binding are updated between when the descriptor set is bound in a command buffer and when that command buffer is submitted to a queue, then the submission will use the most recently set descriptors for this binding and the updates do not invalidate the command buffer. Descriptor bindings created with this flag are also partially exempt from the external synchronization requirement in vkUpdateDescriptorSetWithTemplateKHR and vkUpdateDescriptorSets. They can be updated concurrently with the set being bound to a command buffer in another thread, but not concurrently with the set being reset or freed. -
VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT_EXTindicates that descriptors in this binding that are not dynamically used need not contain valid descriptors at the time the descriptors are consumed. A descriptor is dynamically used if any shader invocation executes an instruction that performs any memory access using the descriptor. -
VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT_EXTindicates that descriptors in this binding can be updated after a command buffer has bound this descriptor set, or while a command buffer that uses this descriptor set is pending execution, as long as the descriptors that are updated are not used by those command buffers. IfVK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT_EXTis also set, then descriptors can be updated as long as they are not dynamically used by any shader invocations. IfVK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT_EXTis not set, then descriptors can be updated as long as they are not statically used by any shader invocations. -
VK_DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT_EXTindicates that this descriptor binding has a variable size that will be specified when a descriptor set is allocated using this layout. The value ofdescriptorCountis treated as an upper bound on the size of the binding. This must only be used for the last binding in the descriptor set layout (i.e. the binding with the largest value ofbinding). For the purposes of counting against limits such asmaxDescriptorSet* andmaxPerStageDescriptor*, the full value ofdescriptorCountis counted.
|
Note
Note that while |
To query information about whether a descriptor set layout can be created, call:
void vkGetDescriptorSetLayoutSupport(
VkDevice device,
const VkDescriptorSetLayoutCreateInfo* pCreateInfo,
VkDescriptorSetLayoutSupport* pSupport);
or the equivalent command
void vkGetDescriptorSetLayoutSupportKHR(
VkDevice device,
const VkDescriptorSetLayoutCreateInfo* pCreateInfo,
VkDescriptorSetLayoutSupport* pSupport);
-
deviceis the logical device that would create the descriptor set layout. -
pCreateInfois a pointer to an instance of the VkDescriptorSetLayoutCreateInfo structure specifying the state of the descriptor set layout object. -
pSupportpoints to a VkDescriptorSetLayoutSupport structure in which information about support for the descriptor set layout object is returned.
Some implementations have limitations on what fits in a descriptor set which
are not easily expressible in terms of existing limits like
maxDescriptorSet*, for example if all descriptor types share a limited
space in memory but each descriptor is a different size or alignment.
This command returns information about whether a descriptor set satisfies
this limit.
If the descriptor set layout satisfies the
VkPhysicalDeviceMaintenance3Properties::maxPerSetDescriptors
limit, this command is guaranteed to return VK_TRUE in
VkDescriptorSetLayoutSupport::supported.
If the descriptor set layout exceeds the
VkPhysicalDeviceMaintenance3Properties::maxPerSetDescriptors
limit, whether the descriptor set layout is supported is
implementation-dependent and may depend on whether the descriptor sizes and
alignments cause the layout to exceed an internal limit.
This command does not consider other limits such as
maxPerStageDescriptor*, and so a descriptor set layout that is
supported according to this command must still satisfy the pipeline layout
limits such as maxPerStageDescriptor* in order to be used in a
pipeline layout.
|
Note
This is a |
Information about support for the descriptor set layout is returned in an
instance of the VkDescriptorSetLayoutSupport structure:
typedef struct VkDescriptorSetLayoutSupport {
VkStructureType sType;
void* pNext;
VkBool32 supported;
} VkDescriptorSetLayoutSupport;
or the equivalent
typedef VkDescriptorSetLayoutSupport VkDescriptorSetLayoutSupportKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
supportedspecifies whether the descriptor set layout can be created.
supported is set to VK_TRUE if the descriptor set can be
created, or else is set to VK_FALSE.
If the pNext chain of a VkDescriptorSetLayoutSupport structure
includes a VkDescriptorSetVariableDescriptorCountLayoutSupportEXT
structure, then that structure returns additional information about whether
the descriptor set layout is supported.
typedef struct VkDescriptorSetVariableDescriptorCountLayoutSupportEXT {
VkStructureType sType;
void* pNext;
uint32_t maxVariableDescriptorCount;
} VkDescriptorSetVariableDescriptorCountLayoutSupportEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
maxVariableDescriptorCountindicates the maximum number of descriptors supported in the highest numbered binding of the layout, if that binding is variable-sized.
If the create info includes a variable-sized descriptor, then
supported is determined assuming the requested size of the
variable-sized descriptor, and maxVariableDescriptorCount is set to
the maximum size of that descriptor that can be successfully created (which
is greater than or equal to the requested size passed in).
If the create info does not include a variable-sized descriptor or if the
VkPhysicalDeviceDescriptorIndexingFeaturesEXT::descriptorBindingVariableDescriptorCount
feature is not enabled, then maxVariableDescriptorCount is set to
zero.
For the purposes of this command, a variable-sized descriptor binding with a
descriptorCount of zero is treated as if the descriptorCount is
one, and thus the binding is not ignored and the maximum descriptor count
will be returned.
If the layout is not supported, then the value written to
maxVariableDescriptorCount is undefined.
The following examples show a shader snippet using two descriptor sets, and application code that creates corresponding descriptor set layouts.
//
// binding to a single sampled image descriptor in set 0
//
layout (set=0, binding=0) uniform texture2D mySampledImage;
//
// binding to an array of sampled image descriptors in set 0
//
layout (set=0, binding=1) uniform texture2D myArrayOfSampledImages[12];
//
// binding to a single uniform buffer descriptor in set 1
//
layout (set=1, binding=0) uniform myUniformBuffer
{
vec4 myElement[32];
};
...
%1 = OpExtInstImport "GLSL.std.450"
...
OpName %9 "mySampledImage"
OpName %14 "myArrayOfSampledImages"
OpName %18 "myUniformBuffer"
OpMemberName %18 0 "myElement"
OpName %20 ""
OpDecorate %9 DescriptorSet 0
OpDecorate %9 Binding 0
OpDecorate %14 DescriptorSet 0
OpDecorate %14 Binding 1
OpDecorate %17 ArrayStride 16
OpMemberDecorate %18 0 Offset 0
OpDecorate %18 Block
OpDecorate %20 DescriptorSet 1
OpDecorate %20 Binding 0
%2 = OpTypeVoid
%3 = OpTypeFunction %2
%6 = OpTypeFloat 32
%7 = OpTypeImage %6 2D 0 0 0 1 Unknown
%8 = OpTypePointer UniformConstant %7
%9 = OpVariable %8 UniformConstant
%10 = OpTypeInt 32 0
%11 = OpConstant %10 12
%12 = OpTypeArray %7 %11
%13 = OpTypePointer UniformConstant %12
%14 = OpVariable %13 UniformConstant
%15 = OpTypeVector %6 4
%16 = OpConstant %10 32
%17 = OpTypeArray %15 %16
%18 = OpTypeStruct %17
%19 = OpTypePointer Uniform %18
%20 = OpVariable %19 Uniform
...
VkResult myResult;
const VkDescriptorSetLayoutBinding myDescriptorSetLayoutBinding[] =
{
// binding to a single image descriptor
{
0, // binding
VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE, // descriptorType
1, // descriptorCount
VK_SHADER_STAGE_FRAGMENT_BIT, // stageFlags
NULL // pImmutableSamplers
},
// binding to an array of image descriptors
{
1, // binding
VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE, // descriptorType
12, // descriptorCount
VK_SHADER_STAGE_FRAGMENT_BIT, // stageFlags
NULL // pImmutableSamplers
},
// binding to a single uniform buffer descriptor
{
0, // binding
VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, // descriptorType
1, // descriptorCount
VK_SHADER_STAGE_FRAGMENT_BIT, // stageFlags
NULL // pImmutableSamplers
}
};
const VkDescriptorSetLayoutCreateInfo myDescriptorSetLayoutCreateInfo[] =
{
// Create info for first descriptor set with two descriptor bindings
{
VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO, // sType
NULL, // pNext
0, // flags
2, // bindingCount
&myDescriptorSetLayoutBinding[0] // pBindings
},
// Create info for second descriptor set with one descriptor binding
{
VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO, // sType
NULL, // pNext
0, // flags
1, // bindingCount
&myDescriptorSetLayoutBinding[2] // pBindings
}
};
VkDescriptorSetLayout myDescriptorSetLayout[2];
//
// Create first descriptor set layout
//
myResult = vkCreateDescriptorSetLayout(
myDevice,
&myDescriptorSetLayoutCreateInfo[0],
NULL,
&myDescriptorSetLayout[0]);
//
// Create second descriptor set layout
//
myResult = vkCreateDescriptorSetLayout(
myDevice,
&myDescriptorSetLayoutCreateInfo[1],
NULL,
&myDescriptorSetLayout[1]);
To destroy a descriptor set layout, call:
void vkDestroyDescriptorSetLayout(
VkDevice device,
VkDescriptorSetLayout descriptorSetLayout,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the descriptor set layout. -
descriptorSetLayoutis the descriptor set layout to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
13.2.2. Pipeline Layouts
Access to descriptor sets from a pipeline is accomplished through a pipeline layout. Zero or more descriptor set layouts and zero or more push constant ranges are combined to form a pipeline layout object which describes the complete set of resources that can be accessed by a pipeline. The pipeline layout represents a sequence of descriptor sets with each having a specific layout. This sequence of layouts is used to determine the interface between shader stages and shader resources. Each pipeline is created using a pipeline layout.
Pipeline layout objects are represented by VkPipelineLayout handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkPipelineLayout)
To create a pipeline layout, call:
VkResult vkCreatePipelineLayout(
VkDevice device,
const VkPipelineLayoutCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkPipelineLayout* pPipelineLayout);
-
deviceis the logical device that creates the pipeline layout. -
pCreateInfois a pointer to an instance of the VkPipelineLayoutCreateInfo structure specifying the state of the pipeline layout object. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pPipelineLayoutpoints to aVkPipelineLayouthandle in which the resulting pipeline layout object is returned.
The VkPipelineLayoutCreateInfo structure is defined as:
typedef struct VkPipelineLayoutCreateInfo {
VkStructureType sType;
const void* pNext;
VkPipelineLayoutCreateFlags flags;
uint32_t setLayoutCount;
const VkDescriptorSetLayout* pSetLayouts;
uint32_t pushConstantRangeCount;
const VkPushConstantRange* pPushConstantRanges;
} VkPipelineLayoutCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
setLayoutCountis the number of descriptor sets included in the pipeline layout. -
pSetLayoutsis a pointer to an array ofVkDescriptorSetLayoutobjects. -
pushConstantRangeCountis the number of push constant ranges included in the pipeline layout. -
pPushConstantRangesis a pointer to an array ofVkPushConstantRangestructures defining a set of push constant ranges for use in a single pipeline layout. In addition to descriptor set layouts, a pipeline layout also describes how many push constants can be accessed by each stage of the pipeline.NotePush constants represent a high speed path to modify constant data in pipelines that is expected to outperform memory-backed resource updates.
typedef VkFlags VkPipelineLayoutCreateFlags;
VkPipelineLayoutCreateFlags is a bitmask type for setting a mask, but
is currently reserved for future use.
The VkPushConstantRange structure is defined as:
typedef struct VkPushConstantRange {
VkShaderStageFlags stageFlags;
uint32_t offset;
uint32_t size;
} VkPushConstantRange;
-
stageFlagsis a set of stage flags describing the shader stages that will access a range of push constants. If a particular stage is not included in the range, then accessing members of that range of push constants from the corresponding shader stage will result in undefined data being read. -
offsetandsizeare the start offset and size, respectively, consumed by the range. Bothoffsetandsizeare in units of bytes and must be a multiple of 4. The layout of the push constant variables is specified in the shader.
Once created, pipeline layouts are used as part of pipeline creation (see Pipelines), as part of binding descriptor sets (see Descriptor Set Binding), and as part of setting push constants (see Push Constant Updates). Pipeline creation accepts a pipeline layout as input, and the layout may be used to map (set, binding, arrayElement) tuples to implementation resources or memory locations within a descriptor set. The assignment of implementation resources depends only on the bindings defined in the descriptor sets that comprise the pipeline layout, and not on any shader source.
All resource variables statically used in all shaders
in a pipeline must be declared with a (set,binding,arrayElement) that
exists in the corresponding descriptor set layout and is of an appropriate
descriptor type and includes the set of shader stages it is used by in
stageFlags.
The pipeline layout can include entries that are not used by a particular
pipeline, or that are dead-code eliminated from any of the shaders.
The pipeline layout allows the application to provide a consistent set of
bindings across multiple pipeline compiles, which enables those pipelines to
be compiled in a way that the implementation may cheaply switch pipelines
without reprogramming the bindings.
Similarly, the push constant block declared in each shader (if present)
must only place variables at offsets that are each included in a push
constant range with stageFlags including the bit corresponding to the
shader stage that uses it.
The pipeline layout can include ranges or portions of ranges that are not
used by a particular pipeline, or for which the variables have been
dead-code eliminated from any of the shaders.
There is a limit on the total number of resources of each type that can be included in bindings in all descriptor set layouts in a pipeline layout as shown in Pipeline Layout Resource Limits. The “Total Resources Available” column gives the limit on the number of each type of resource that can be included in bindings in all descriptor sets in the pipeline layout. Some resource types count against multiple limits. Additionally, there are limits on the total number of each type of resource that can be used in any pipeline stage as described in Shader Resource Limits.
| Total Resources Available | Resource Types |
|---|---|
|
sampler |
combined image sampler |
|
|
sampled image |
combined image sampler |
|
uniform texel buffer |
|
|
storage image |
storage texel buffer |
|
|
uniform buffer |
uniform buffer dynamic |
|
|
uniform buffer dynamic |
|
storage buffer |
storage buffer dynamic |
|
|
storage buffer dynamic |
|
input attachment |
To destroy a pipeline layout, call:
void vkDestroyPipelineLayout(
VkDevice device,
VkPipelineLayout pipelineLayout,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the pipeline layout. -
pipelineLayoutis the pipeline layout to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
Pipeline Layout Compatibility
Two pipeline layouts are defined to be “compatible for push constants” if they were created with identical push constant ranges. Two pipeline layouts are defined to be “compatible for set N” if they were created with identically defined descriptor set layouts for sets zero through N, and if they were created with identical push constant ranges.
When binding a descriptor set (see Descriptor Set Binding) to set number N, if the previously bound descriptor sets for sets zero through N-1 were all bound using compatible pipeline layouts, then performing this binding does not disturb any of the lower numbered sets. If, additionally, the previous bound descriptor set for set N was bound using a pipeline layout compatible for set N, then the bindings in sets numbered greater than N are also not disturbed.
Similarly, when binding a pipeline, the pipeline can correctly access any previously bound descriptor sets which were bound with compatible pipeline layouts, as long as all lower numbered sets were also bound with compatible layouts.
Layout compatibility means that descriptor sets can be bound to a command buffer for use by any pipeline created with a compatible pipeline layout, and without having bound a particular pipeline first. It also means that descriptor sets can remain valid across a pipeline change, and the same resources will be accessible to the newly bound pipeline.
|
Note
Place the least frequently changing descriptor sets near the start of the pipeline layout, and place the descriptor sets representing the most frequently changing resources near the end. When pipelines are switched, only the descriptor set bindings that have been invalidated will need to be updated and the remainder of the descriptor set bindings will remain in place. |
The maximum number of descriptor sets that can be bound to a pipeline
layout is queried from physical device properties (see
maxBoundDescriptorSets in Limits).
const VkDescriptorSetLayout layouts[] = { layout1, layout2 };
const VkPushConstantRange ranges[] =
{
{
VK_PIPELINE_STAGE_VERTEX_SHADER_BIT, // stageFlags
0, // offset
4 // size
},
{
VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT, // stageFlags
4, // offset
4 // size
},
};
const VkPipelineLayoutCreateInfo createInfo =
{
VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO, // sType
NULL, // pNext
0, // flags
2, // setLayoutCount
layouts, // pSetLayouts
2, // pushConstantRangeCount
ranges // pPushConstantRanges
};
VkPipelineLayout myPipelineLayout;
myResult = vkCreatePipelineLayout(
myDevice,
&createInfo,
NULL,
&myPipelineLayout);
13.2.3. Allocation of Descriptor Sets
A descriptor pool maintains a pool of descriptors, from which descriptor sets are allocated. Descriptor pools are externally synchronized, meaning that the application must not allocate and/or free descriptor sets from the same pool in multiple threads simultaneously.
Descriptor pools are represented by VkDescriptorPool handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDescriptorPool)
To create a descriptor pool object, call:
VkResult vkCreateDescriptorPool(
VkDevice device,
const VkDescriptorPoolCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkDescriptorPool* pDescriptorPool);
-
deviceis the logical device that creates the descriptor pool. -
pCreateInfois a pointer to an instance of the VkDescriptorPoolCreateInfo structure specifying the state of the descriptor pool object. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pDescriptorPoolpoints to aVkDescriptorPoolhandle in which the resulting descriptor pool object is returned.
pAllocator controls host memory allocation as described in the
Memory Allocation chapter.
The created descriptor pool is returned in pDescriptorPool.
Additional information about the pool is passed in an instance of the
VkDescriptorPoolCreateInfo structure:
typedef struct VkDescriptorPoolCreateInfo {
VkStructureType sType;
const void* pNext;
VkDescriptorPoolCreateFlags flags;
uint32_t maxSets;
uint32_t poolSizeCount;
const VkDescriptorPoolSize* pPoolSizes;
} VkDescriptorPoolCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis a bitmask of VkDescriptorPoolCreateFlagBits specifying certain supported operations on the pool. -
maxSetsis the maximum number of descriptor sets that can be allocated from the pool. -
poolSizeCountis the number of elements inpPoolSizes. -
pPoolSizesis a pointer to an array ofVkDescriptorPoolSizestructures, each containing a descriptor type and number of descriptors of that type to be allocated in the pool.
If multiple VkDescriptorPoolSize structures appear in the
pPoolSizes array then the pool will be created with enough storage for
the total number of descriptors of each type.
Fragmentation of a descriptor pool is possible and may lead to descriptor set allocation failures. A failure due to fragmentation is defined as failing a descriptor set allocation despite the sum of all outstanding descriptor set allocations from the pool plus the requested allocation requiring no more than the total number of descriptors requested at pool creation. Implementations provide certain guarantees of when fragmentation must not cause allocation failure, as described below.
If a descriptor pool has not had any descriptor sets freed since it was
created or most recently reset then fragmentation must not cause an
allocation failure (note that this is always the case for a pool created
without the VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT bit
set).
Additionally, if all sets allocated from the pool since it was created or
most recently reset use the same number of descriptors (of each type) and
the requested allocation also uses that same number of descriptors (of each
type), then fragmentation must not cause an allocation failure.
If an allocation failure occurs due to fragmentation, an application can create an additional descriptor pool to perform further descriptor set allocations.
If flags has the
VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT_EXT bit set,
descriptor pool creation may fail with the error
VK_ERROR_FRAGMENTATION_EXT if the total number of descriptors across
all pools (including this one) created with this bit set exceeds
maxUpdateAfterBindDescriptorsInAllPools, or if fragmentation of the
underlying hardware resources occurs.
Bits which can be set in VkDescriptorPoolCreateInfo::flags to
enable operations on a descriptor pool are:
typedef enum VkDescriptorPoolCreateFlagBits {
VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT = 0x00000001,
VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT_EXT = 0x00000002,
} VkDescriptorPoolCreateFlagBits;
-
VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BITspecifies that descriptor sets can return their individual allocations to the pool, i.e. all of vkAllocateDescriptorSets, vkFreeDescriptorSets, and vkResetDescriptorPool are allowed. Otherwise, descriptor sets allocated from the pool must not be individually freed back to the pool, i.e. only vkAllocateDescriptorSets and vkResetDescriptorPool are allowed. -
VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT_EXTspecifies that descriptor sets allocated from this pool can include bindings with theVK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT_EXTbit set. It is valid to allocate descriptor sets that have bindings that don’t set theVK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT_EXTbit from a pool that hasVK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT_EXTset.
typedef VkFlags VkDescriptorPoolCreateFlags;
VkDescriptorPoolCreateFlags is a bitmask type for setting a mask of
zero or more VkDescriptorPoolCreateFlagBits.
The VkDescriptorPoolSize structure is defined as:
typedef struct VkDescriptorPoolSize {
VkDescriptorType type;
uint32_t descriptorCount;
} VkDescriptorPoolSize;
-
typeis the type of descriptor. -
descriptorCountis the number of descriptors of that type to allocate.
To destroy a descriptor pool, call:
void vkDestroyDescriptorPool(
VkDevice device,
VkDescriptorPool descriptorPool,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the descriptor pool. -
descriptorPoolis the descriptor pool to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
When a pool is destroyed, all descriptor sets allocated from the pool are implicitly freed and become invalid. Descriptor sets allocated from a given pool do not need to be freed before destroying that descriptor pool.
Descriptor sets are allocated from descriptor pool objects, and are
represented by VkDescriptorSet handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDescriptorSet)
To allocate descriptor sets from a descriptor pool, call:
VkResult vkAllocateDescriptorSets(
VkDevice device,
const VkDescriptorSetAllocateInfo* pAllocateInfo,
VkDescriptorSet* pDescriptorSets);
-
deviceis the logical device that owns the descriptor pool. -
pAllocateInfois a pointer to an instance of the VkDescriptorSetAllocateInfo structure describing parameters of the allocation. -
pDescriptorSetsis a pointer to an array ofVkDescriptorSethandles in which the resulting descriptor set objects are returned.
The allocated descriptor sets are returned in pDescriptorSets.
When a descriptor set is allocated, the initial state is largely
uninitialized and all descriptors are undefined.
However, the descriptor set can be bound in a command buffer without
causing errors or exceptions.
For descriptor set bindings created with the
VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT_EXT bit set, all descriptors
in that binding that are dynamically used must have been populated before
the descriptor set is consumed.
For descriptor set bindings created without the
VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT_EXT bit set, all descriptors
in that binding that are statically used must have been populated before
the descriptor set is consumed.
Entries that are not used by a pipeline can have uninitialized descriptors
or descriptors of resources that have been destroyed, and executing a draw
or dispatch with such a descriptor set bound does not cause undefined
behavior.
This means applications need not populate unused entries with dummy
descriptors.
If a call to vkAllocateDescriptorSets would cause the total number of
descriptor sets allocated from the pool to exceed the value of
VkDescriptorPoolCreateInfo::maxSets used to create
pAllocateInfo→descriptorPool, then the allocation may fail due
to lack of space in the descriptor pool.
Similarly, the allocation may fail due to lack of space if the call to
vkAllocateDescriptorSets would cause the number of any given
descriptor type to exceed the sum of all the descriptorCount members
of each element of VkDescriptorPoolCreateInfo::pPoolSizes with a
member equal to that type.
If the allocation fails due to no more space in the descriptor pool, and not
because of system or device memory exhaustion, then
VK_ERROR_OUT_OF_POOL_MEMORY must be returned.
vkAllocateDescriptorSets can be used to create multiple descriptor
sets.
If the creation of any of those descriptor sets fails, then the
implementation must destroy all successfully created descriptor set objects
from this command, set all entries of the pDescriptorSets array to
VK_NULL_HANDLE and return the error.
The VkDescriptorSetAllocateInfo structure is defined as:
typedef struct VkDescriptorSetAllocateInfo {
VkStructureType sType;
const void* pNext;
VkDescriptorPool descriptorPool;
uint32_t descriptorSetCount;
const VkDescriptorSetLayout* pSetLayouts;
} VkDescriptorSetAllocateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
descriptorPoolis the pool which the sets will be allocated from. -
descriptorSetCountdetermines the number of descriptor sets to be allocated from the pool. -
pSetLayoutsis an array of descriptor set layouts, with each member specifying how the corresponding descriptor set is allocated.
If the pNext chain of a VkDescriptorSetAllocateInfo structure
includes a VkDescriptorSetVariableDescriptorCountAllocateInfoEXT
structure, then that structure includes an array of descriptor counts for
variable descriptor count bindings, one for each descriptor set being
allocated.
The VkDescriptorSetVariableDescriptorCountAllocateInfoEXT structure is
defined as:
typedef struct VkDescriptorSetVariableDescriptorCountAllocateInfoEXT {
VkStructureType sType;
const void* pNext;
uint32_t descriptorSetCount;
const uint32_t* pDescriptorCounts;
} VkDescriptorSetVariableDescriptorCountAllocateInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
descriptorSetCountis zero or the number of elements inpDescriptorCounts. -
pDescriptorCountsis an array of descriptor counts, with each member specifying the number of descriptors in a variable descriptor count binding in the corresponding descriptor set being allocated.
If descriptorSetCount is zero or this structure is not included in the
pNext chain, then the variable lengths are considered to be zero.
Otherwise, pDescriptorCounts[i] is the number of descriptors in the
variable count descriptor binding in the corresponding descriptor set
layout.
If VkDescriptorSetAllocateInfo::pSetLayouts[i] does not include
a variable count descriptor binding, then pDescriptorCounts[i] is
ignored.
To free allocated descriptor sets, call:
VkResult vkFreeDescriptorSets(
VkDevice device,
VkDescriptorPool descriptorPool,
uint32_t descriptorSetCount,
const VkDescriptorSet* pDescriptorSets);
-
deviceis the logical device that owns the descriptor pool. -
descriptorPoolis the descriptor pool from which the descriptor sets were allocated. -
descriptorSetCountis the number of elements in thepDescriptorSetsarray. -
pDescriptorSetsis an array of handles toVkDescriptorSetobjects.
After a successful call to vkFreeDescriptorSets, all descriptor sets
in pDescriptorSets are invalid.
To return all descriptor sets allocated from a given pool to the pool, rather than freeing individual descriptor sets, call:
VkResult vkResetDescriptorPool(
VkDevice device,
VkDescriptorPool descriptorPool,
VkDescriptorPoolResetFlags flags);
-
deviceis the logical device that owns the descriptor pool. -
descriptorPoolis the descriptor pool to be reset. -
flagsis reserved for future use.
Resetting a descriptor pool recycles all of the resources from all of the descriptor sets allocated from the descriptor pool back to the descriptor pool, and the descriptor sets are implicitly freed.
typedef VkFlags VkDescriptorPoolResetFlags;
VkDescriptorPoolResetFlags is a bitmask type for setting a mask, but
is currently reserved for future use.
13.2.4. Descriptor Set Updates
Once allocated, descriptor sets can be updated with a combination of write and copy operations. To update descriptor sets, call:
void vkUpdateDescriptorSets(
VkDevice device,
uint32_t descriptorWriteCount,
const VkWriteDescriptorSet* pDescriptorWrites,
uint32_t descriptorCopyCount,
const VkCopyDescriptorSet* pDescriptorCopies);
-
deviceis the logical device that updates the descriptor sets. -
descriptorWriteCountis the number of elements in thepDescriptorWritesarray. -
pDescriptorWritesis a pointer to an array of VkWriteDescriptorSet structures describing the descriptor sets to write to. -
descriptorCopyCountis the number of elements in thepDescriptorCopiesarray. -
pDescriptorCopiesis a pointer to an array of VkCopyDescriptorSet structures describing the descriptor sets to copy between.
The operations described by pDescriptorWrites are performed first,
followed by the operations described by pDescriptorCopies.
Within each array, the operations are performed in the order they appear in
the array.
Each element in the pDescriptorWrites array describes an operation
updating the descriptor set using descriptors for resources specified in the
structure.
Each element in the pDescriptorCopies array is a
VkCopyDescriptorSet structure describing an operation copying
descriptors between sets.
If the dstSet member of any element of pDescriptorWrites or
pDescriptorCopies is bound, accessed, or modified by any command that
was recorded to a command buffer which is currently in the
recording or executable state,
and any of the descriptor bindings that are updated were not created with
the VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT_EXT or
VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT_EXT bits set,
that command buffer becomes invalid.
The VkWriteDescriptorSet structure is defined as:
typedef struct VkWriteDescriptorSet {
VkStructureType sType;
const void* pNext;
VkDescriptorSet dstSet;
uint32_t dstBinding;
uint32_t dstArrayElement;
uint32_t descriptorCount;
VkDescriptorType descriptorType;
const VkDescriptorImageInfo* pImageInfo;
const VkDescriptorBufferInfo* pBufferInfo;
const VkBufferView* pTexelBufferView;
} VkWriteDescriptorSet;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
dstSetis the destination descriptor set to update. -
dstBindingis the descriptor binding within that set. -
dstArrayElementis the starting element in that array. -
descriptorCountis the number of descriptors to update (the number of elements inpImageInfo,pBufferInfo, orpTexelBufferView). -
descriptorTypeis a VkDescriptorType specifying the type of each descriptor inpImageInfo,pBufferInfo, orpTexelBufferView, as described below. It must be the same type as that specified inVkDescriptorSetLayoutBindingfordstSetatdstBinding. The type of the descriptor also controls which array the descriptors are taken from. -
pImageInfopoints to an array of VkDescriptorImageInfo structures or is ignored, as described below. -
pBufferInfopoints to an array of VkDescriptorBufferInfo structures or is ignored, as described below. -
pTexelBufferViewpoints to an array of VkBufferView handles as described in the Buffer Views section or is ignored, as described below.
Only one of pImageInfo, pBufferInfo, or pTexelBufferView
members is used according to the descriptor type specified in the
descriptorType member of the containing VkWriteDescriptorSet
structure, as specified below.
If the dstBinding has fewer than descriptorCount array elements
remaining starting from dstArrayElement, then the remainder will be
used to update the subsequent binding - dstBinding+1 starting at
array element zero.
If a binding has a descriptorCount of zero, it is skipped.
This behavior applies recursively, with the update affecting consecutive
bindings as needed to update all descriptorCount descriptors.
The type of descriptors in a descriptor set is specified by
VkWriteDescriptorSet::descriptorType, which must be one of the
values:
typedef enum VkDescriptorType {
VK_DESCRIPTOR_TYPE_SAMPLER = 0,
VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER = 1,
VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE = 2,
VK_DESCRIPTOR_TYPE_STORAGE_IMAGE = 3,
VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER = 4,
VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER = 5,
VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER = 6,
VK_DESCRIPTOR_TYPE_STORAGE_BUFFER = 7,
VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC = 8,
VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC = 9,
VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT = 10,
} VkDescriptorType;
-
VK_DESCRIPTOR_TYPE_SAMPLERspecifies a sampler descriptor. -
VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLERspecifies a combined image sampler descriptor. -
VK_DESCRIPTOR_TYPE_SAMPLED_IMAGEspecifies a sampled image descriptor. -
VK_DESCRIPTOR_TYPE_STORAGE_IMAGEspecifies a storage image descriptor. -
VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFERspecifies a uniform texel buffer descriptor. -
VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFERspecifies a storage texel buffer descriptor. -
VK_DESCRIPTOR_TYPE_UNIFORM_BUFFERspecifies a uniform buffer descriptor. -
VK_DESCRIPTOR_TYPE_STORAGE_BUFFERspecifies a storage buffer descriptor. -
VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMICspecifies a dynamic uniform buffer descriptor. -
VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMICspecifies a dynamic storage buffer descriptor. -
VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENTspecifies a input attachment descriptor.
When a descriptor set is updated via elements of VkWriteDescriptorSet,
members of pImageInfo, pBufferInfo and pTexelBufferView
are only accessed by the implementation when they correspond to descriptor
type being defined - otherwise they are ignored.
The members accessed are as follows for each descriptor type:
-
For
VK_DESCRIPTOR_TYPE_SAMPLER, only thesamplemember of each element of VkWriteDescriptorSet::pImageInfois accessed. -
For
VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE,VK_DESCRIPTOR_TYPE_STORAGE_IMAGE, orVK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT, only theimageViewandimageLayoutmembers of each element of VkWriteDescriptorSet::pImageInfoare accessed. -
For
VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, all members of each element of VkWriteDescriptorSet::pImageInfoare accessed. -
For
VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,VK_DESCRIPTOR_TYPE_STORAGE_BUFFER,VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC, orVK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC, all members of each element of VkWriteDescriptorSet::pBufferInfoare accessed. -
For
VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFERorVK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER, each element of VkWriteDescriptorSet::pTexelBufferViewis accessed.
The VkDescriptorBufferInfo structure is defined as:
typedef struct VkDescriptorBufferInfo {
VkBuffer buffer;
VkDeviceSize offset;
VkDeviceSize range;
} VkDescriptorBufferInfo;
-
bufferis the buffer resource. -
offsetis the offset in bytes from the start ofbuffer. Access to buffer memory via this descriptor uses addressing that is relative to this starting offset. -
rangeis the size in bytes that is used for this descriptor update, orVK_WHOLE_SIZEto use the range fromoffsetto the end of the buffer.
|
Note
When setting |
For VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC and
VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC descriptor types,
offset is the base offset from which the dynamic offset is applied and
range is the static size used for all dynamic offsets.
The VkDescriptorImageInfo structure is defined as:
typedef struct VkDescriptorImageInfo {
VkSampler sampler;
VkImageView imageView;
VkImageLayout imageLayout;
} VkDescriptorImageInfo;
-
sampleris a sampler handle, and is used in descriptor updates for typesVK_DESCRIPTOR_TYPE_SAMPLERandVK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLERif the binding being updated does not use immutable samplers. -
imageViewis an image view handle, and is used in descriptor updates for typesVK_DESCRIPTOR_TYPE_SAMPLED_IMAGE,VK_DESCRIPTOR_TYPE_STORAGE_IMAGE,VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, andVK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT. -
imageLayoutis the layout that the image subresources accessible fromimageViewwill be in at the time this descriptor is accessed.imageLayoutis used in descriptor updates for typesVK_DESCRIPTOR_TYPE_SAMPLED_IMAGE,VK_DESCRIPTOR_TYPE_STORAGE_IMAGE,VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, andVK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT.
Members of VkDescriptorImageInfo that are not used in an update (as
described above) are ignored.
The VkCopyDescriptorSet structure is defined as:
typedef struct VkCopyDescriptorSet {
VkStructureType sType;
const void* pNext;
VkDescriptorSet srcSet;
uint32_t srcBinding;
uint32_t srcArrayElement;
VkDescriptorSet dstSet;
uint32_t dstBinding;
uint32_t dstArrayElement;
uint32_t descriptorCount;
} VkCopyDescriptorSet;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
srcSet,srcBinding, andsrcArrayElementare the source set, binding, and array element, respectively. -
dstSet,dstBinding, anddstArrayElementare the destination set, binding, and array element, respectively. -
descriptorCountis the number of descriptors to copy from the source to destination. IfdescriptorCountis greater than the number of remaining array elements in the source or destination binding, those affect consecutive bindings in a manner similar to VkWriteDescriptorSet above.
13.2.5. Descriptor Update Templates
A descriptor update template specifies a mapping from descriptor update information in host memory to descriptors in a descriptor set. It is designed to avoid passing redundant information to the driver when frequently updating the same set of descriptors in descriptor sets.
Descriptor update template objects are represented by
VkDescriptorUpdateTemplate handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDescriptorUpdateTemplate)
or the equivalent
typedef VkDescriptorUpdateTemplate VkDescriptorUpdateTemplateKHR;
13.2.6. Descriptor Set Updates with Templates
Updating a large VkDescriptorSet array can be an expensive operation
since an application must specify one VkWriteDescriptorSet structure
for each descriptor or descriptor array to update, each of which
re-specifies the same state when updating the same descriptor in multiple
descriptor sets.
For cases when an application wishes to update the same set of descriptors
in multiple descriptor sets allocated using the same
VkDescriptorSetLayout, vkUpdateDescriptorSetWithTemplate can be
used as a replacement for vkUpdateDescriptorSets.
VkDescriptorUpdateTemplate allows implementations to convert a set of
descriptor update operations on a single descriptor set to an internal
format that, in conjunction with vkUpdateDescriptorSetWithTemplate
or vkCmdPushDescriptorSetWithTemplateKHR
, can be more efficient compared to calling vkUpdateDescriptorSets
or vkCmdPushDescriptorSetKHR
.
The descriptors themselves are not specified in the
VkDescriptorUpdateTemplate, rather, offsets into an application
provided pointer to host memory are specified, which are combined with a
pointer passed to vkUpdateDescriptorSetWithTemplate
or vkCmdPushDescriptorSetWithTemplateKHR
.
This allows large batches of updates to be executed without having to
convert application data structures into a strictly-defined Vulkan data
structure.
To create a descriptor update template, call:
VkResult vkCreateDescriptorUpdateTemplate(
VkDevice device,
const VkDescriptorUpdateTemplateCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkDescriptorUpdateTemplate* pDescriptorUpdateTemplate);
or the equivalent command
VkResult vkCreateDescriptorUpdateTemplateKHR(
VkDevice device,
const VkDescriptorUpdateTemplateCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkDescriptorUpdateTemplate* pDescriptorUpdateTemplate);
-
deviceis the logical device that creates the descriptor update template. -
pCreateInfois a pointer to an instance of the VkDescriptorUpdateTemplateCreateInfo structure specifying the set of descriptors to update with a single call to vkCmdPushDescriptorSetWithTemplateKHR or vkUpdateDescriptorSetWithTemplate. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pDescriptorUpdateTemplatepoints to aVkDescriptorUpdateTemplatehandle in which the resulting descriptor update template object is returned.
The VkDescriptorUpdateTemplateCreateInfo structure is defined as:
typedef struct VkDescriptorUpdateTemplateCreateInfo {
VkStructureType sType;
void* pNext;
VkDescriptorUpdateTemplateCreateFlags flags;
uint32_t descriptorUpdateEntryCount;
const VkDescriptorUpdateTemplateEntry* pDescriptorUpdateEntries;
VkDescriptorUpdateTemplateType templateType;
VkDescriptorSetLayout descriptorSetLayout;
VkPipelineBindPoint pipelineBindPoint;
VkPipelineLayout pipelineLayout;
uint32_t set;
} VkDescriptorUpdateTemplateCreateInfo;
or the equivalent
typedef VkDescriptorUpdateTemplateCreateInfo VkDescriptorUpdateTemplateCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
descriptorUpdateEntryCountis the number of elements in thepDescriptorUpdateEntriesarray. -
pDescriptorUpdateEntriesis a pointer to an array of VkDescriptorUpdateTemplateEntry structures describing the descriptors to be updated by the descriptor update template. -
templateTypeSpecifies the type of the descriptor update template. If set toVK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_DESCRIPTOR_SETit can only be used to update descriptor sets with a fixeddescriptorSetLayout. If set toVK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHRit can only be used to push descriptor sets using the providedpipelineBindPoint,pipelineLayout, andsetnumber. -
descriptorSetLayoutis the descriptor set layout the parameter update template will be used with. All descriptor sets which are going to be updated through the newly created descriptor update template must be created with this layout.descriptorSetLayoutis the descriptor set layout used to build the descriptor update template. All descriptor sets which are going to be updated through the newly created descriptor update template must be created with a layout that matches (is the same as, or defined identically to) this layout. This parameter is ignored iftemplateTypeis notVK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_DESCRIPTOR_SET. -
pipelineBindPointis a VkPipelineBindPoint indicating whether the descriptors will be used by graphics pipelines or compute pipelines. This parameter is ignored iftemplateTypeis notVK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHR -
pipelineLayoutis aVkPipelineLayoutobject used to program the bindings. This parameter is ignored iftemplateTypeis notVK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHR -
setis the set number of the descriptor set in the pipeline layout that will be updated. This parameter is ignored iftemplateTypeis notVK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHR
typedef VkFlags VkDescriptorUpdateTemplateCreateFlags;
or the equivalent
typedef VkDescriptorUpdateTemplateCreateFlags VkDescriptorUpdateTemplateCreateFlagsKHR;
VkDescriptorUpdateTemplateCreateFlags is a bitmask type for setting a
mask, but is currently reserved for future use.
The descriptor update template type is determined by the
VkDescriptorUpdateTemplateCreateInfo::templateType property,
which takes the following values:
typedef enum VkDescriptorUpdateTemplateType {
VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_DESCRIPTOR_SET = 0,
VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHR = 1,
VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_DESCRIPTOR_SET_KHR = VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_DESCRIPTOR_SET,
} VkDescriptorUpdateTemplateType;
or the equivalent
typedef VkDescriptorUpdateTemplateType VkDescriptorUpdateTemplateTypeKHR;
-
VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_DESCRIPTOR_SETspecifies that the descriptor update template will be used for descriptor set updates only. -
VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHRspecifies that the descriptor update template will be used for push descriptor updates only.
The VkDescriptorUpdateTemplateEntry structure is defined as:
typedef struct VkDescriptorUpdateTemplateEntry {
uint32_t dstBinding;
uint32_t dstArrayElement;
uint32_t descriptorCount;
VkDescriptorType descriptorType;
size_t offset;
size_t stride;
} VkDescriptorUpdateTemplateEntry;
or the equivalent
typedef VkDescriptorUpdateTemplateEntry VkDescriptorUpdateTemplateEntryKHR;
-
dstBindingis the descriptor binding to update when using this descriptor update template. -
dstArrayElementis the starting element in the array belonging todstBinding. -
descriptorCountis the number of descriptors to update. IfdescriptorCountis greater than the number of remaining array elements in the destination binding, those affect consecutive bindings in a manner similar to VkWriteDescriptorSet above. -
descriptorTypeis a VkDescriptorType specifying the type of the descriptor. -
offsetis the offset in bytes of the first binding in the raw data structure. -
strideis the stride in bytes between two consecutive array elements of the descriptor update informations in the raw data structure. The actual pointer ptr for each array element j of update entry i is computed using the following formula:const char *ptr = (const char *)pData + pDescriptorUpdateEntries[i].offset + j * pDescriptorUpdateEntries[i].strideThe stride is useful in case the bindings are stored in structs along with other data.
To destroy a descriptor update template, call:
void vkDestroyDescriptorUpdateTemplate(
VkDevice device,
VkDescriptorUpdateTemplate descriptorUpdateTemplate,
const VkAllocationCallbacks* pAllocator);
or the equivalent command
void vkDestroyDescriptorUpdateTemplateKHR(
VkDevice device,
VkDescriptorUpdateTemplate descriptorUpdateTemplate,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that has been used to create the descriptor update template -
descriptorUpdateTemplateis the descriptor update template to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
Once a VkDescriptorUpdateTemplate has been created, descriptor sets
can be updated by calling:
void vkUpdateDescriptorSetWithTemplate(
VkDevice device,
VkDescriptorSet descriptorSet,
VkDescriptorUpdateTemplate descriptorUpdateTemplate,
const void* pData);
or the equivalent command
void vkUpdateDescriptorSetWithTemplateKHR(
VkDevice device,
VkDescriptorSet descriptorSet,
VkDescriptorUpdateTemplate descriptorUpdateTemplate,
const void* pData);
-
deviceis the logical device that updates the descriptor sets. -
descriptorSetis the descriptor set to update -
descriptorUpdateTemplateis theVkDescriptorUpdateTemplatewhich specifies the update mapping betweenpDataand the descriptor set to update. -
pDatais a pointer to memory which contains one or more structures of VkDescriptorImageInfo, VkDescriptorBufferInfo, or VkBufferView used to write the descriptors.
struct AppBufferView {
VkBufferView bufferView;
uint32_t applicationRelatedInformation;
};
struct AppDataStructure
{
VkDescriptorImageInfo imageInfo; // a single image info
VkDescriptorBufferInfo bufferInfoArray[3]; // 3 buffer infos in an array
AppBufferView bufferView[2]; // An application defined structure containing a bufferView
// ... some more application related data
};
const VkDescriptorUpdateTemplateEntry descriptorUpdateTemplateEntries[] =
{
// binding to a single image descriptor
{
0, // binding
0, // dstArrayElement
1, // descriptorCount
VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, // descriptorType
offsetof(AppDataStructure, imageInfo), // offset
0 // stride is not required if descriptorCount is 1.
},
// binding to an array of buffer descriptors
{
0, // binding
0, // dstArrayElement
3, // descriptorCount
VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, // descriptorType
offsetof(AppDataStructure, bufferInfoArray), // offset
sizeof(VkDescriptorBufferInfo) // stride, descriptor buffer infos are compact
},
// binding to an array of buffer views
{
0, // binding
3, // dstArrayElement
1, // descriptorCount
VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER, // descriptorType
offsetof(AppDataStructure, bufferView), // offset
sizeof(AppBufferView) // stride, bufferViews do not have to be compact
},
};
// create an descriptor update template for descriptor set updates
const VkDescriptorUpdateTemplateCreateInfo createInfo =
{
VK_STRUCTURE_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_CREATE_INFO, // sType
NULL, // pNext
0, // flags
3, // descriptorUpdateEntryCount
descriptorUpdateTemplateEntries, // pDescriptorUpdateEntries
VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_DESCRIPTOR_SET, // templateType
myLayout, // descriptorSetLayout
0, // pipelineBindPoint, ignored by given templateType
0, // pipelineLayout, ignored by given templateType
0, // set, ignored by given templateType
};
VkDescriptorUpdateTemplate myDescriptorUpdateTemplate;
myResult = vkCreateDescriptorUpdateTemplate(
myDevice,
&createInfo,
NULL,
&myDescriptorUpdateTemplate);
}
AppDataStructure appData;
// fill appData here or cache it in your engine
vkUpdateDescriptorSetWithTemplate(myDevice, myDescriptorSet, myDescriptorUpdateTemplate, &appData);
13.2.7. Descriptor Set Binding
To bind one or more descriptor sets to a command buffer, call:
void vkCmdBindDescriptorSets(
VkCommandBuffer commandBuffer,
VkPipelineBindPoint pipelineBindPoint,
VkPipelineLayout layout,
uint32_t firstSet,
uint32_t descriptorSetCount,
const VkDescriptorSet* pDescriptorSets,
uint32_t dynamicOffsetCount,
const uint32_t* pDynamicOffsets);
-
commandBufferis the command buffer that the descriptor sets will be bound to. -
pipelineBindPointis a VkPipelineBindPoint indicating whether the descriptors will be used by graphics pipelines or compute pipelines. There is a separate set of bind points for each of graphics and compute, so binding one does not disturb the other. -
layoutis aVkPipelineLayoutobject used to program the bindings. -
firstSetis the set number of the first descriptor set to be bound. -
descriptorSetCountis the number of elements in thepDescriptorSetsarray. -
pDescriptorSetsis an array of handles toVkDescriptorSetobjects describing the descriptor sets to write to. -
dynamicOffsetCountis the number of dynamic offsets in thepDynamicOffsetsarray. -
pDynamicOffsetsis a pointer to an array ofuint32_tvalues specifying dynamic offsets.
vkCmdBindDescriptorSets causes the sets numbered [firstSet..
firstSet+descriptorSetCount-1] to use the bindings stored in
pDescriptorSets[0..descriptorSetCount-1] for subsequent
rendering commands (either compute or graphics, according to the
pipelineBindPoint).
Any bindings that were previously applied via these sets are no longer
valid.
Once bound, a descriptor set affects rendering of subsequent graphics or compute commands in the command buffer until a different set is bound to the same set number, or else until the set is disturbed as described in Pipeline Layout Compatibility.
A compatible descriptor set must be bound for all set numbers that any shaders in a pipeline access, at the time that a draw or dispatch command is recorded to execute using that pipeline. However, if none of the shaders in a pipeline statically use any bindings with a particular set number, then no descriptor set need be bound for that set number, even if the pipeline layout includes a non-trivial descriptor set layout for that set number.
If any of the sets being bound include dynamic uniform or storage buffers,
then pDynamicOffsets includes one element for each array element in
each dynamic descriptor type binding in each set.
Values are taken from pDynamicOffsets in an order such that all
entries for set N come before set N+1; within a set, entries are ordered by
the binding numbers in the descriptor set layouts; and within a binding
array, elements are in order.
dynamicOffsetCount must equal the total number of dynamic descriptors
in the sets being bound.
The effective offset used for dynamic uniform and storage buffer bindings is
the sum of the relative offset taken from pDynamicOffsets, and the
base address of the buffer plus base offset in the descriptor set.
The length of the dynamic uniform and storage buffer bindings is the buffer
range as specified in the descriptor set.
Each of the pDescriptorSets must be compatible with the pipeline
layout specified by layout.
The layout used to program the bindings must also be compatible with the
pipeline used in subsequent graphics or compute commands, as defined in the
Pipeline Layout Compatibility section.
The descriptor set contents bound by a call to vkCmdBindDescriptorSets
may be consumed at the following times:
-
For descriptor bindings created with the
VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT_EXTbit set, the contents may be consumed when the command buffer is submitted to a queue, or during shader execution of the resulting draws and dispatches, or any time in between. Otherwise, -
during host execution of the command, or during shader execution of the resulting draws and dispatches, or any time in between.
Thus, the contents of a descriptor set binding must not be altered (overwritten by an update command, or freed) between the first point in time that it may be consumed, and when the command completes executing on the queue.
The contents of pDynamicOffsets are consumed immediately during
execution of vkCmdBindDescriptorSets.
Once all pending uses have completed, it is legal to update and reuse a
descriptor set.
13.2.8. Push Descriptor Updates
In addition to allocating descriptor sets and binding them to a command buffer, an application can record descriptor updates into the command buffer.
To push descriptor updates into a command buffer, call:
void vkCmdPushDescriptorSetKHR(
VkCommandBuffer commandBuffer,
VkPipelineBindPoint pipelineBindPoint,
VkPipelineLayout layout,
uint32_t set,
uint32_t descriptorWriteCount,
const VkWriteDescriptorSet* pDescriptorWrites);
-
commandBufferis the command buffer that the descriptors will be recorded in. -
pipelineBindPointis a VkPipelineBindPoint indicating whether the descriptors will be used by graphics pipelines or compute pipelines. There is a separate set of push descriptor bindings for each of graphics and compute, so binding one does not disturb the other. -
layoutis aVkPipelineLayoutobject used to program the bindings. -
setis the set number of the descriptor set in the pipeline layout that will be updated. -
descriptorWriteCountis the number of elements in thepDescriptorWritesarray. -
pDescriptorWritesis a pointer to an array of VkWriteDescriptorSet structures describing the descriptors to be updated.
Push descriptors are a small bank of descriptors whose storage is internally managed by the command buffer rather than being written into a descriptor set and later bound to a command buffer. Push descriptors allow for incremental updates of descriptors without managing the lifetime of descriptor sets.
When a command buffer begins recording, all push descriptors have undefined
contents.
Push descriptors can be updated incrementally and cause shaders to use the
updated descriptors for subsequent rendering commands (either compute or
graphics, according to the pipelineBindPoint) until the descriptor is
overwritten, or else until the set is disturbed as described in
Pipeline Layout Compatibility.
When the set is disturbed or push descriptors with a different descriptor
set layout are set, all push descriptors become invalid.
Valid descriptors must be pushed for all bindings that any shaders in a pipeline access, at the time that a draw or dispatch command is recorded to execute using that pipeline. This includes immutable sampler descriptors, which must be pushed before they are accessed by a pipeline. However, if none of the shaders in a pipeline statically use certain bindings in the push descriptor set, then those descriptors need not be valid.
Push descriptors do not use dynamic offsets.
Instead, the corresponding non-dynamic descriptor types can be used and the
offset member of VkDescriptorBufferInfo can be changed each
time the descriptor is written.
Each element of pDescriptorWrites is interpreted as in
VkWriteDescriptorSet, except the dstSet member is ignored.
To push an immutable sampler, use a VkWriteDescriptorSet with
dstBinding and dstArrayElement selecting the immutable sampler’s
binding.
If the descriptor type is VK_DESCRIPTOR_TYPE_SAMPLER, the
pImageInfo parameter is ignored and the immutable sampler is taken
from the push descriptor set layout in the pipeline layout.
If the descriptor type is VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER,
the sampler member of the pImageInfo parameter is ignored and
the immutable sampler is taken from the push descriptor set layout in the
pipeline layout.
13.2.9. Push Descriptor Updates with Descriptor Update Templates
It is also possible to use a descriptor update template to specify the push descriptors to update. To do so, call:
void vkCmdPushDescriptorSetWithTemplateKHR(
VkCommandBuffer commandBuffer,
VkDescriptorUpdateTemplate descriptorUpdateTemplate,
VkPipelineLayout layout,
uint32_t set,
const void* pData);
-
commandBufferis the command buffer that the descriptors will be recorded in. -
descriptorUpdateTemplateA descriptor update template which defines how to interpret the descriptor information in pData. -
layoutis aVkPipelineLayoutobject used to program the bindings. It must be compatible with the layout used to create thedescriptorUpdateTemplatehandle. -
setis the set number of the descriptor set in the pipeline layout that will be updated. This must be the same number used to create thedescriptorUpdateTemplatehandle. -
pDataPoints to memory which contains the descriptors for the templated update.
struct AppBufferView {
VkBufferView bufferView;
uint32_t applicationRelatedInformation;
};
struct AppDataStructure
{
VkDescriptorImageInfo imageInfo; // a single image info
// ... some more application related data
};
const VkDescriptorUpdateTemplateEntry descriptorUpdateTemplateEntries[] =
{
// binding to a single image descriptor
{
0, // binding
0, // dstArrayElement
1, // descriptorCount
VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, // descriptorType
offsetof(AppDataStructure, imageInfo), // offset
0 // stride is not required if descriptorCount is 1.
}
};
// create an descriptor update template for descriptor set updates
const VkDescriptorUpdateTemplateCreateInfo createInfo =
{
VK_STRUCTURE_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_CREATE_INFO, // sType
NULL, // pNext
0, // flags
1, // descriptorUpdateEntryCount
descriptorUpdateTemplateEntries, // pDescriptorUpdateEntries
VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHR, // templateType
0, // descriptorSetLayout, ignored by given templateType
VK_PIPELINE_BIND_POINT_GRAPHICS, // pipelineBindPoint
myPipelineLayout, // pipelineLayout
0, // set
};
VkDescriptorUpdateTemplate myDescriptorUpdateTemplate;
myResult = vkCreateDescriptorUpdateTemplate(
myDevice,
&createInfo,
NULL,
&myDescriptorUpdateTemplate);
}
AppDataStructure appData;
// fill appData here or cache it in your engine
vkCmdPushDescriptorSetWithTemplateKHR(myCmdBuffer, myDescriptorUpdateTemplate, myPipelineLayout, 0,&appData);
13.2.10. Push Constant Updates
As described above in section Pipeline Layouts, the pipeline layout defines shader push constants which are updated via Vulkan commands rather than via writes to memory or copy commands.
|
Note
Push constants represent a high speed path to modify constant data in pipelines that is expected to outperform memory-backed resource updates. |
The values of push constants are undefined at the start of a command buffer.
To update push constants, call:
void vkCmdPushConstants(
VkCommandBuffer commandBuffer,
VkPipelineLayout layout,
VkShaderStageFlags stageFlags,
uint32_t offset,
uint32_t size,
const void* pValues);
-
commandBufferis the command buffer in which the push constant update will be recorded. -
layoutis the pipeline layout used to program the push constant updates. -
stageFlagsis a bitmask of VkShaderStageFlagBits specifying the shader stages that will use the push constants in the updated range. -
offsetis the start offset of the push constant range to update, in units of bytes. -
sizeis the size of the push constant range to update, in units of bytes. -
pValuesis an array ofsizebytes containing the new push constant values.
14. Shader Interfaces
When a pipeline is created, the set of shaders specified in the
corresponding Vk*PipelineCreateInfo structure are implicitly linked at
a number of different interfaces.
Interface definitions make use of the following SPIR-V decorations:
-
DescriptorSetandBinding -
Location,Component, andIndex -
Flat,NoPerspective,Centroid, andSample -
BlockandBufferBlock -
InputAttachmentIndex -
Offset,ArrayStride, andMatrixStride -
BuiltIn
This specification describes valid uses for Vulkan of these decorations. Any other use of one of these decorations is invalid.
14.1. Shader Input and Output Interfaces
When multiple stages are present in a pipeline, the outputs of one stage form an interface with the inputs of the next stage. When such an interface involves a shader, shader outputs are matched against the inputs of the next stage, and shader inputs are matched against the outputs of the previous stage.
There are two classes of variables that can be matched between shader stages, built-in variables and user-defined variables. Each class has a different set of matching criteria. Generally, when non-shader stages are between shader stages, the user-defined variables, and most built-in variables, form an interface between the shader stages.
The variables forming the input or output interfaces are listed as
operands to the OpEntryPoint instruction and are declared with the
Input or Output storage classes, respectively, in the SPIR-V
module.
Output variables of a shader stage have undefined values until the
shader writes to them or uses the Initializer operand when declaring
the variable.
14.1.1. Built-in Interface Block
Shader built-in variables meeting the following requirements define the built-in interface block. They must
-
be explicitly declared (there are no implicit built-ins),
-
be identified with a
BuiltIndecoration, -
form object types as described in the Built-in Variables section, and
-
be declared in a block whose top-level members are the built-ins.
Built-ins only participate in interface matching if they are declared in
such a block.
They must not have any Location or Component decorations.
There must be no more than one built-in interface block per shader per interface.
14.1.2. User-defined Variable Interface
The remaining variables listed by OpEntryPoint with the Input or
Output storage class form the user-defined variable interface.
By default such variables have a type with a width of 32 or 64.
If an implementation supports
storageInputOutput16,
user-defined variables in the Input and Output storage classes
can also have types with a width of 16.
These variables must be identified with a Location decoration and can
also be identified with a Component decoration.
14.1.3. Interface Matching
A user-defined output variable is considered to match an input variable in
the subsequent stage if the two variables are declared with the same
Location and Component decoration and match in type and
decoration, except that interpolation
decorations are not required to match.
For the purposes of interface matching, variables declared without a
Component decoration are considered to have a Component decoration
of zero.
|
Note
Matching rules for passthrough geometry shaders are slightly different and are described in the Passthrough Interface Matching section. |
Variables or block members declared as structures are considered to match in type if and only if the structure members match in type, decoration, number, and declaration order. Variables or block members declared as arrays are considered to match in type only if both declarations specify the same element type and size.
Tessellation control shader per-vertex output variables and blocks, and tessellation control, tessellation evaluation, and geometry shader per-vertex input variables and blocks are required to be declared as arrays, with each element representing input or output values for a single vertex of a multi-vertex primitive. For the purposes of interface matching, the outermost array dimension of such variables and blocks is ignored.
At an interface between two non-fragment shader stages, the built-in interface block must match exactly, as described above. At an interface involving the fragment shader inputs, the presence or absence of any built-in output does not affect the interface matching.
At an interface between two shader stages, the user-defined variable interface must match exactly, as described above.
Any input value to a shader stage is well-defined as long as the preceding stages writes to a matching output, as described above.
Additionally, scalar and vector inputs are well-defined if there is a corresponding output satisfying all of the following conditions:
-
the input and output match exactly in decoration,
-
the output is a vector with the same basic type and has at least as many components as the input, and
-
the common component type of the input and output is 16-bit integer or floating-point, or 32-bit integer or floating-point (64-bit component types are excluded).
In this case, the components of the input will be taken from the first components of the output, and any extra components of the output will be ignored.
14.1.4. Location Assignment
This section describes how many locations are consumed by a given type. As mentioned above, geometry shader inputs, tessellation control shader inputs and outputs, and tessellation evaluation inputs all have an additional level of arrayness relative to other shader inputs and outputs. This outer array level is removed from the type before considering how many locations the type consumes.
The Location value specifies an interface slot comprised of a 32-bit
four-component vector conveyed between stages.
The Component specifies
components within these vector
locations.
Only types with widths of
16,
32 or 64 are supported in shader interfaces.
Inputs and outputs of the following types consume a single interface location:
-
16-bit scalar and vector types, and
-
32-bit scalar and vector types, and
-
64-bit scalar and 2-component vector types.
64-bit three- and four-component vectors consume two consecutive locations.
If a declared input or output is an array of size n and each element takes m locations, it will be assigned m × n consecutive locations starting with the location specified.
If the declared input or output is an n × m 16-, 32- or 64-bit matrix, it will be assigned multiple locations starting with the location specified. The number of locations assigned for each matrix will be the same as for an n-element array of m-component vectors.
The layout of a structure type used as an Input or Output depends
on whether it is also a Block (i.e. has a Block decoration).
If it is a not a Block, then the structure type must have a
Location decoration.
Its members are assigned consecutive locations in their declaration order,
with the first member assigned to the location specified for the structure
type.
The members, and their nested types, must not themselves have Location
decorations.
If the structure type is a Block but without a Location, then each
of its members must have a Location decoration.
If it is a Block with a Location decoration, then its members are
assigned consecutive locations in declaration order, starting from the first
member which is initially assigned the location specified for the
Block.
Any member with its own Location decoration is assigned that location.
Each remaining member is assigned the location after the immediately
preceding member in declaration order.
The locations consumed by block and structure members are determined by applying the rules above in a depth-first traversal of the instantiated members as though the structure or block member were declared as an input or output variable of the same type.
Any two inputs listed as operands on the same OpEntryPoint must not be
assigned the same location, either explicitly or implicitly.
Any two outputs listed as operands on the same OpEntryPoint must not
be assigned the same location, either explicitly or implicitly.
The number of input and output locations available for a shader input or output interface are limited, and dependent on the shader stage as described in Shader Input and Output Locations.
| Shader Interface | Locations Available |
|---|---|
vertex input |
|
vertex output |
|
tessellation control input |
|
tessellation control output |
|
tessellation evaluation input |
|
tessellation evaluation output |
|
geometry input |
|
geometry output |
|
fragment input |
|
fragment output |
|
14.1.5. Component Assignment
The Component decoration allows the Location to be more finely
specified for scalars and vectors, down to the individual components within
a location that are consumed.
The components within a location are 0, 1, 2, and 3.
A variable or block member starting at component N will consume components
N, N+1, N+2, …
up through its size.
For 16-, and 32-bit types,
it is invalid if this sequence of components gets larger than 3.
A scalar 64-bit type will consume two of these components in sequence, and a
two-component 64-bit vector type will consume all four components available
within a location.
A three- or four-component 64-bit vector type must not specify a
Component decoration.
A three-component 64-bit vector type will consume all four components of the
first location and components 0 and 1 of the second location.
This leaves components 2 and 3 available for other component-qualified
declarations.
A scalar or two-component 64-bit data type must not specify a
Component decoration of 1 or 3.
A Component decoration must not be specified for any type that is not
a scalar or vector.
14.2. Vertex Input Interface
When the vertex stage is present in a pipeline, the vertex shader input
variables form an interface with the vertex input attributes.
The vertex shader input variables are matched by the Location and
Component decorations to the vertex input attributes specified in the
pVertexInputState member of the VkGraphicsPipelineCreateInfo
structure.
The vertex shader input variables listed by OpEntryPoint with the
Input storage class form the vertex input interface.
These variables must be identified with a Location decoration and can
also be identified with a Component decoration.
For the purposes of interface matching: variables declared without a
Component decoration are considered to have a Component decoration
of zero.
The number of available vertex input locations is given by the
maxVertexInputAttributes member of the VkPhysicalDeviceLimits
structure.
See Attribute Location and Component Assignment for details.
All vertex shader inputs declared as above must have a corresponding attribute and binding in the pipeline.
14.3. Fragment Output Interface
When the fragment stage is present in a pipeline, the fragment shader
outputs form an interface with the output attachments of the current
subpass.
The fragment shader output variables are matched by the Location and
Component decorations to the color attachments specified in the
pColorAttachments array of the VkSubpassDescription structure
that describes the subpass that the fragment shader is executed in.
The fragment shader output variables listed by OpEntryPoint with the
Output storage class form the fragment output interface.
These variables must be identified with a Location decoration.
They can also be identified with a Component decoration and/or an
Index decoration.
For the purposes of interface matching: variables declared without a
Component decoration are considered to have a Component decoration
of zero, and variables declared without an Index decoration are
considered to have an Index decoration of zero.
A fragment shader output variable identified with a Location decoration
of i is directed to the color attachment indicated by
pColorAttachments[i], after passing through the blending unit as
described in Blending, if enabled.
Locations are consumed as described in
Location Assignment.
The number of available fragment output locations is given by the
maxFragmentOutputAttachments member of the
VkPhysicalDeviceLimits structure.
Components of the output variables are assigned as described in Component Assignment. Output components identified as 0, 1, 2, and 3 will be directed to the R, G, B, and A inputs to the blending unit, respectively, or to the output attachment if blending is disabled. If two variables are placed within the same location, they must have the same underlying type (floating-point or integer). The input to blending or color attachment writes is undefined for components which do not correspond to a fragment shader output.
Fragment outputs identified with an Index of zero are directed to the
first input of the blending unit associated with the corresponding
Location.
Outputs identified with an Index of one are directed to the second
input of the corresponding blending unit.
No component aliasing of output variables is allowed, that is there must not be two output variables which have the same location, component, and index, either explicitly declared or implied.
Output values written by a fragment shader must be declared with either
OpTypeFloat or OpTypeInt, and a Width of 32.
If storageInputOutput16 is supported, output values written by a
fragment shader can be also declared with either OpTypeFloat or
OpTypeInt and a Width of 16.
Composites of these types are also permitted.
If the color attachment has a signed or unsigned normalized fixed-point
format, color values are assumed to be floating-point and are converted to
fixed-point as described in Conversion from Floating-Point to Normalized Fixed-Point; If the color
attachment has an integer format, color values are assumed to be integers
and converted to the bit-depth of the target.
Any value that cannot be represented in the attachment’s format is
undefined.
For any other attachment format no conversion is performed.
If the type of the values written by the fragment shader do not match the
format of the corresponding color attachment, the result is undefined for
those components.
14.4. Fragment Input Attachment Interface
When a fragment stage is present in a pipeline, the fragment shader subpass
inputs form an interface with the input attachments of the current subpass.
The fragment shader subpass input variables are matched by
InputAttachmentIndex decorations to the input attachments specified in
the pInputAttachments array of the VkSubpassDescription
structure that describes the subpass that the fragment shader is executed
in.
The fragment shader subpass input variables with the UniformConstant
storage class and a decoration of InputAttachmentIndex that are
statically used by OpEntryPoint form the fragment input attachment
interface.
These variables must be declared with a type of OpTypeImage, a
Dim operand of SubpassData, and a Sampled operand of 2.
A subpass input variable identified with an InputAttachmentIndex
decoration of i reads from the input attachment indicated by
pInputAttachments[i] member of VkSubpassDescription.
If the subpass input variable is declared as an array of size N, it consumes
N consecutive input attachments, starting with the index specified.
There must not be more than one input variable with the same
InputAttachmentIndex whether explicitly declared or implied by an array
declaration.
The number of available input attachment indices is given by the
maxPerStageDescriptorInputAttachments member of the
VkPhysicalDeviceLimits structure.
Variables identified with the InputAttachmentIndex must only be used
by a fragment stage.
The basic data type (floating-point, integer, unsigned integer) of the
subpass input must match the basic format of the corresponding input
attachment, or the values of subpass loads from these variables are
undefined.
See Input Attachment for more details.
14.5. Shader Resource Interface
When a shader stage accesses buffer or image resources, as described in the Resource Descriptors section, the shader resource variables must be matched with the pipeline layout that is provided at pipeline creation time.
The set of shader resources that form the shader resource interface for a
stage are the variables statically used by OpEntryPoint with the
storage class of Uniform, UniformConstant, or PushConstant.
For the fragment shader, this includes the fragment input attachment interface.
The shader resource interface consists of two sub-interfaces: the push constant interface and the descriptor set interface.
14.5.1. Push Constant Interface
The shader variables defined with a storage class of PushConstant that
are statically used by the shader entry points for the pipeline define the
push constant interface.
They must be:
-
typed as
OpTypeStruct, -
identified with a
Blockdecoration, and -
laid out explicitly using the
Offset,ArrayStride, andMatrixStridedecorations as specified in Offset and Stride Assignment.
There must be no more than one push constant block statically used per shader entry point.
Each variable in a push constant block must be placed at an Offset
such that the entire constant value is entirely contained within the
VkPushConstantRange for each OpEntryPoint that uses it, and the
stageFlags for that range must specify the appropriate
VkShaderStageFlagBits for that stage.
The Offset decoration for any variable in a push constant block must
not cause the space required for that variable to extend outside the range
[0, maxPushConstantsSize).
Any variable in a push constant block that is declared as an array must only be accessed with dynamically uniform indices.
14.5.2. Descriptor Set Interface
The descriptor set interface is comprised of the shader variables with the
storage class of Uniform or UniformConstant (including the
variables in the fragment input attachment
interface) that are statically used by the shader entry points for the
pipeline.
These variables must have DescriptorSet and Binding decorations
specified, which are assigned and matched with the
VkDescriptorSetLayout objects in the pipeline layout as described in
DescriptorSet and Binding Assignment.
Variables identified with the UniformConstant storage class are used
only as handles to refer to opaque resources.
Such variables must be typed as OpTypeImage, OpTypeSampler,
OpTypeSampledImage, or an array of one of these types.
The Sampled Type of an OpTypeImage declaration must match
the same basic data type as the corresponding resource, or the values
obtained by reading or sampling from this image are undefined.
The Image Format of an OpTypeImage declaration must not be
Unknown, for variables which are used for OpImageRead,
OpImageSparseRead, or OpImageWrite operations, except under the
following conditions:
-
For
OpImageWrite, if theshaderStorageImageWriteWithoutFormatfeature is enabled and the shader module declares theStorageImageWriteWithoutFormatcapability. -
For
OpImageReadorOpImageSparseRead, if theshaderStorageImageReadWithoutFormatfeature is enabled and the shader module declares theStorageImageReadWithoutFormatcapability.
The Image Format of an OpTypeImage declaration must not be
Unknown, for variables which are used for OpAtomic* operations.
Variables identified with the Uniform storage class are used to access
transparent buffer backed resources.
Such variables must be:
-
typed as
OpTypeStruct, or an array of this type, -
identified with a
BlockorBufferBlockdecoration, and -
laid out explicitly using the
Offset,ArrayStride, andMatrixStridedecorations as specified in Offset and Stride Assignment.
Variables identified with the StorageBuffer storage class are used to
access transparent buffer backed resources.
Such variables must be:
-
typed as
OpTypeStruct, or an array of this type, -
identified with a
Blockdecoration, and -
laid out explicitly using the
Offset,ArrayStride, andMatrixStridedecorations as specified in Offset and Stride Assignment.
The Offset decoration for any member of a Block-decorated variable
in the Uniform storage class must not cause the space required for
that variable to extend outside the range [0,
maxUniformBufferRange).
The Offset decoration for any member of a Block-decorated variable
in the StorageBuffer storage class must not cause the space required
for that variable to extend outside the range [0,
maxStorageBufferRange).
Variables identified with a storage class of UniformConstant and a
decoration of InputAttachmentIndex must be declared as described in
Fragment Input Attachment Interface.
Each shader variable in the descriptor set interface must be of a type that
corresponds to the descriptorType in the descriptor set layout binding
that the variable is assigned to, as described in
DescriptorSet and Binding
Assignment.
See Shader Resource and Descriptor
Type Correspondence for the relationship between shader types and
descriptor types.
SPIR-V variables decorated with a descriptor set and binding that identify a
combined image sampler descriptor
can have a type of OpTypeImage, OpTypeSampler (Sampled=1),
or OpTypeSampledImage.
Arrays of any of these types can be indexed with constant integral expressions. The following features must be enabled and capabilities must be declared in order to index such arrays with dynamically uniform or non-uniform indices:
-
Storage images (except storage texel buffers and input attachments):
-
Dynamically uniform:
shaderStorageImageArrayDynamicIndexingandStorageImageArrayDynamicIndexing -
Non-uniform:
shaderStorageImageArrayNonUniformIndexingandStorageImageArrayNonUniformIndexingEXT
-
-
Storage texel buffers:
-
Dynamically uniform:
shaderStorageTexelBufferArrayDynamicIndexingandStorageTexelBufferArrayDynamicIndexingEXT -
Non-uniform:
shaderStorageTexelBufferArrayNonUniformIndexingandStorageTexelBufferArrayNonUniformIndexingEXT
-
-
Input attachments:
-
Dynamically uniform:
shaderInputAttachmentArrayDynamicIndexingandInputAttachmentArrayDynamicIndexingEXT -
Non-uniform:
shaderInputAttachmentArrayNonUniformIndexingandInputAttachmentArrayNonUniformIndexingEXT
-
-
Sampled images (except uniform texel buffers):
-
Dynamically uniform:
shaderSampledImageArrayDynamicIndexingandSampledImageArrayDynamicIndexing -
Non-uniform:
shaderSampledImageArrayNonUniformIndexingandSampledImageArrayNonUniformIndexingEXT
-
-
Uniform texel buffers:
-
Dynamically uniform:
shaderUniformTexelBufferArrayDynamicIndexingandUniformTexelBufferArrayDynamicIndexingEXT -
Non-uniform:
shaderUniformTexelBufferArrayNonUniformIndexingandUniformTexelBufferArrayNonUniformIndexingEXT
-
-
Uniform buffers:
-
Dynamically uniform:
shaderUniformBufferArrayDynamicIndexingandUniformBufferArrayDynamicIndexing -
Non-uniform:
shaderUniformBufferArrayNonUniformIndexingandUniformBufferArrayNonUniformIndexingEXT
-
-
Storage buffers:
-
Dynamically uniform:
shaderStorageBufferArrayDynamicIndexingandStorageBufferArrayDynamicIndexing -
Non-uniform:
shaderStorageBufferArrayNonUniformIndexingandStorageBufferArrayNonUniformIndexingEXT
-
If an instruction loads from or stores to a resource (including atomics and image instructions) and the resource descriptor being accessed is not dynamically uniform, then the corresponding non-uniform indexing feature must be enabled and the capability must be declared. If an instruction loads from or stores to a resource (including atomics and image instructions) and the resource descriptor being accessed is not uniform, then the corresponding dynamic indexing or non-uniform feature must be enabled and the capability must be declared.
If sampler Y’CBCR conversion is enabled, the combined image sampler
must be indexed only by constant integral expressions when aggregated into
arrays in shader code, irrespective of the
shaderSampledImageArrayDynamicIndexing feature.
| Resource type | Descriptor Type |
|---|---|
sampler |
|
sampled image |
|
storage image |
|
combined image sampler |
|
uniform texel buffer |
|
storage texel buffer |
|
uniform buffer |
|
storage buffer |
|
input attachment |
|
| Resource type | Storage Class | Type | Decoration(s)1 |
|---|---|---|---|
sampler |
|
|
|
sampled image |
|
|
|
storage image |
|
|
|
combined image sampler |
|
|
|
uniform texel buffer |
|
|
|
storage texel buffer |
|
|
|
uniform buffer |
|
|
|
storage buffer |
|
|
|
|
|
||
input attachment |
|
|
|
- 1
-
in addition to
DescriptorSetandBinding
14.5.3. DescriptorSet and Binding Assignment
A variable decorated with a DescriptorSet decoration of s and a
Binding decoration of b indicates that this variable is
associated with the VkDescriptorSetLayoutBinding that has a
binding equal to b in pSetLayouts[s] that was specified
in VkPipelineLayoutCreateInfo.
DescriptorSet decoration values must be between zero and
maxBoundDescriptorSets minus one, inclusive.
Binding decoration values can be any 32-bit unsigned integer value, as
described in Descriptor Set Layout.
Each descriptor set has its own binding name space.
If the Binding decoration is used with an array, the entire array is
assigned that binding value.
The array must be a single-dimensional array and size of the array must be
no larger than the number of descriptors in the binding.
If the array is runtime-sized, then array elements greater than or equal to
the size of that binding in the bound descriptor set must not be used.
If the array is runtime-sized, the runtimeDescriptorArray feature
must be enabled and the RuntimeDescriptorArrayEXT capability must be
declared.
The index of each element of the array is referred to as the arrayElement.
For the purposes of interface matching and descriptor set
operations, if a resource variable is not an
array, it is treated as if it has an arrayElement of zero.
There is a limit on the number of resources of each type that can be accessed by a pipeline stage as shown in Shader Resource Limits. The “Resources Per Stage” column gives the limit on the number each type of resource that can be statically used for an entry point in any given stage in a pipeline. The “Resource Types” column lists which resource types are counted against the limit. Some resource types count against multiple limits.
The pipeline layout may include descriptor sets and bindings which are not
referenced by any variables statically used by the entry points for the
shader stages in the binding’s stageFlags.
However, if a variable assigned to a given DescriptorSet and
Binding is statically used by the entry point for a shader stage, the
pipeline layout must contain a descriptor set layout binding in that
descriptor set layout and for that binding number, and that binding’s
stageFlags must include the appropriate VkShaderStageFlagBits
for that stage.
The descriptor set layout binding must be of a corresponding descriptor
type, as defined in Shader Resource
and Descriptor Type Correspondence.
|
Note
There are no limits on the number of shader variables that can have overlapping set and binding values in a shader; but which resources are statically used has an impact. If any shader variable identifying a resource is statically used in a shader, then the underlying descriptor bound at the declared set and binding must support the declared type in the shader when the shader executes. If multiple shader variables are declared with the same set and binding
values, and with the same underlying descriptor type, they can all be
statically used within the same shader.
However, accesses are not automatically synchronized, and If multiple shader variables with the same set and binding values are declared in a single shader, but with different declared types, where any of those are not supported by the relevant bound descriptor, that shader can only be executed if the variables with the unsupported type are not statically used. A noteworthy example of using multiple statically-used shader variables
sharing the same descriptor set and binding values is a descriptor of type
|
| Resources per Stage | Resource Types |
|---|---|
|
sampler |
combined image sampler |
|
|
sampled image |
combined image sampler |
|
uniform texel buffer |
|
|
storage image |
storage texel buffer |
|
|
uniform buffer |
uniform buffer dynamic |
|
|
storage buffer |
storage buffer dynamic |
|
|
input attachment1 |
- 1
-
Input attachments can only be used in the fragment shader stage
14.5.4. Offset and Stride Assignment
All variables with a storage class of PushConstant or Uniform
must be explicitly laid out using the Offset, ArrayStride, and
MatrixStride decorations.
There are two different layouts requirements depending on the specific
resources.
Standard Uniform Buffer Layout
The base alignment of the type of an OpTypeStruct member of is
defined recursively as follows:
-
A scalar of size N has a base alignment of N.
-
A two-component vector, with components of size N, has a base alignment of 2 N.
-
A three- or four-component vector, with components of size N, has a base alignment of 4 N.
-
An array has a base alignment equal to the base alignment of its element type, rounded up to a multiple of 16.
-
A structure has a base alignment equal to the largest base alignment of any of its members, rounded up to a multiple of 16.
-
A row-major matrix of C columns has a base alignment equal to the base alignment of a vector of C matrix components.
-
A column-major matrix has a base alignment equal to the base alignment of the matrix column type.
A member is defined to improperly straddle if either of the following are true:
-
It is a vector with total size less than or equal to 16 bytes, and has
Offsetdecorations placing its first byte at F and its last byte at L, where floor(F / 16) != floor(L / 16). -
It is a vector with total size greater than 16 bytes and has its
Offsetdecorations placing its first byte at a non-integer multiple of 16.
Every member of an OpTypeStruct with storage class of Uniform and
a decoration of Block (uniform buffers) must be laid out according to
the following rules:
-
The
Offsetdecoration of a scalar, an array, a structure, or a matrix must be a multiple of its base alignment. -
The
Offsetdecoration of a vector must be an integer multiple of the base alignment of its scalar component type, and must not improperly straddle, as defined above. -
Any
ArrayStrideorMatrixStridedecoration must be an integer multiple of the base alignment of the array or matrix from above. -
The
Offsetdecoration of a member must not place it between the end of a structure or an array and the next multiple of the base alignment of that structure or array. -
The numeric order of
Offsetdecorations need not follow member declaration order.
|
Note
The std140 layout in GLSL satisfies these rules. |
Standard Storage Buffer Layout
Member variables of an OpTypeStruct with a storage class of
PushConstant (push constants), or a storage class of Uniform with
a decoration of BufferBlock (storage buffers)
, or a storage class of StorageBuffer with a decoration of Block
must be laid out as above, except
for array and structure base alignment which do not need to be rounded up to
a multiple of 16.
|
Note
The std430 layout in GLSL satisfies these rules. |
14.6. Built-In Variables
Built-in variables are accessed in shaders by declaring a variable decorated
with a BuiltIn decoration.
The meaning of each BuiltIn decoration is as follows.
In the remainder of this section, the name of a built-in is used
interchangeably with a term equivalent to a variable decorated with that
particular built-in.
Built-ins that represent integer values can be declared as either signed or
unsigned 32-bit integers.
BaryCoordNoPerspAMD-
The
BaryCoordNoPerspAMDdecoration can be used to decorate a fragment shader input variable. This variable will contain the (I,J) pair of the barycentric coordinates corresponding to the fragment evaluated using linear interpolation at the pixel’s center. The K coordinate of the barycentric coordinates can be derived given the identity I + J + K = 1.0. BaryCoordNoPerspCentroidAMD-
The
BaryCoordNoPerspCentroidAMDdecoration can be used to decorate a fragment shader input variable. This variable will contain the (I,J) pair of the barycentric coordinates corresponding to the fragment evaluated using linear interpolation at the centroid. The K coordinate of the barycentric coordinates can be derived given the identity I + J + K = 1.0. BaryCoordNoPerspSampleAMD-
The
BaryCoordNoPerspCentroidAMDdecoration can be used to decorate a fragment shader input variable. This variable will contain the (I,J) pair of the barycentric coordinates corresponding to the fragment evaluated using linear interpolation at each covered sample. The K coordinate of the barycentric coordinates can be derived given the identity I + J + K = 1.0. BaryCoordPullModelAMD-
The
BaryCoordPullModelAMDdecoration can be used to decorate a fragment shader input variable. This variable will contain (1/W, 1/I, 1/J) evaluated at the pixel center and can be used to calculate gradients and then interpolate I, J, and W at any desired sample location. BaryCoordSmoothAMD-
The
BaryCoordSmoothAMDdecoration can be used to decorate a fragment shader input variable. This variable will contain the (I,J) pair of the barycentric coordinates corresponding to the fragment evaluated using perspective interpolation at the pixel’s center. The K coordinate of the barycentric coordinates can be derived given the identity I + J + K = 1.0. BaryCoordSmoothCentroidAMD-
The
BaryCoordSmoothCentroidAMDdecoration can be used to decorate a fragment shader input variable. This variable will contain the (I,J) pair of the barycentric coordinates corresponding to the fragment evaluated using perspective interpolation at the centroid. The K coordinate of the barycentric coordinates can be derived given the identity I + J + K = 1.0. BaryCoordSmoothSampleAMD-
The
BaryCoordSmoothCentroidAMDdecoration can be used to decorate a fragment shader input variable. This variable will contain the (I,J) pair of the barycentric coordinates corresponding to the fragment evaluated using perspective interpolation at each covered sample. The K coordinate of the barycentric coordinates can be derived given the identity I + J + K = 1.0.
BaseInstance-
Decorating a variable with the
BaseInstancebuilt-in will make that variable contain the integer value corresponding to the first instance that was passed to the command that invoked the current vertex shader invocation.BaseInstanceis thefirstInstanceparameter to a direct drawing command or thefirstInstancemember of a structure consumed by an indirect drawing command.The
BaseInstancedecoration must be used only within vertex shaders.The variable decorated with BaseInstance must be declared using the input storage class.
The variable decorated with BaseInstance must be declared as a scalar 32-bit integer.
BaseVertex-
Decorating a variable with the
BaseVertexbuilt-in will make that variable contain the integer value corresponding to the first vertex or vertex offset that was passed to the command that invoked the current vertex shader invocation. For non-indexed drawing commands, this variable is thefirstVertexparameter to a direct drawing command or thefirstVertexmember of the structure consumed by an indirect drawing command. For indexed drawing commands, this variable is thevertexOffsetparameter to a direct drawing command or thevertexOffsetmember of the structure consumed by an indirect drawing command.The
BaseVertexdecoration must be used only within vertex shaders.The variable decorated with
BaseVertexmust be declared using the input storage class.The variable decorated with codeBaseVertex must be declared as a scalar 32-bit integer.
ClipDistance-
Decorating a variable with the
ClipDistancebuilt-in decoration will make that variable contain the mechanism for controlling user clipping.ClipDistanceis an array such that the ith element of the array specifies the clip distance for plane i. A clip distance of 0 means the vertex is on the plane, a positive distance means the vertex is inside the clip half-space, and a negative distance means the point is outside the clip half-space.The
ClipDistancedecoration must be used only within vertex, fragment, tessellation control, tessellation evaluation, and geometry shaders.In vertex shaders, any variable decorated with
ClipDistancemust be declared using theOutputstorage class.In fragment shaders, any variable decorated with
ClipDistancemust be declared using theInputstorage class.In tessellation control, tessellation evaluation, or geometry shaders, any variable decorated with
ClipDistancemust not be in a storage class other thanInputorOutput.Any variable decorated with
ClipDistancemust be declared as an array of 32-bit floating-point values.
|
Note
The array variable decorated with |
|
Note
In the last vertex processing stage, these values will be linearly
interpolated across the primitive and the portion of the primitive with
interpolated distances less than 0 will be considered outside the clip
volume.
If |
CullDistance-
Decorating a variable with the
CullDistancebuilt-in decoration will make that variable contain the mechanism for controlling user culling. If any member of this array is assigned a negative value for all vertices belonging to a primitive, then the primitive is discarded before rasterization.The
CullDistancedecoration must be used only within vertex, fragment, tessellation control, tessellation evaluation, and geometry shaders.In vertex shaders, any variable decorated with
CullDistancemust be declared using theOutputstorage class.In fragment shaders, any variable decorated with
CullDistancemust be declared using theInputstorage class.In tessellation control, tessellation evaluation, or geometry shaders, any variable decorated with
CullDistancemust not be declared in a storage class other than input or output.Any variable decorated with
CullDistancemust be declared as an array of 32-bit floating-point values.
|
Note
In fragment shaders, the values of the |
|
Note
If |
DeviceIndex-
The
DeviceIndexdecoration can be applied to a shader input which will be filled with the device index of the physical device that is executing the current shader invocation. This value will be in the range \([0,max(1,physicalDeviceCount))\), where physicalDeviceCount is thephysicalDeviceCountmember of VkDeviceGroupDeviceCreateInfo.The
DeviceIndexdecoration can be used in any shader.The variable decorated with
DeviceIndexmust be declared using theInputstorage class.The variable decorated with
DeviceIndexmust be declared as a scalar 32-bit integer.
DrawIndex-
Decorating a variable with the
DrawIndexbuilt-in will make that variable contain the integer value corresponding to the zero-based index of the drawing command that invoked the current vertex shader invocation. For indirect drawing commands,DrawIndexbegins at zero and increments by one for each draw command executed. The number of draw commands is given by thedrawCountparameter. For direct drawing commands,DrawIndexis always zero.DrawIndexis dynamically uniform.The
DrawIndexdecoration must be used only within vertex shaders.The variable decorated with
DrawIndexmust be declared using the input storage class.The variable decorated with
DrawIndexmust be declared as a scalar 32-bit integer. FragCoord-
Decorating a variable with the
FragCoordbuilt-in decoration will make that variable contain the framebuffer coordinate \((x,y,z,\frac{1}{w})\) of the fragment being processed. The (x,y) coordinate (0,0) is the upper left corner of the upper left pixel in the framebuffer.When Sample Shading is enabled, the x and y components of
FragCoordreflect the location of one of the samples corresponding to the shader invocation.When sample shading is not enabled, the x and y components of
FragCoordreflect the location of the center of the pixel, (0.5,0.5).The z component of
FragCoordis the interpolated depth value of the primitive.The w component is the interpolated \(\frac{1}{w}\).
The
FragCoorddecoration must be used only within fragment shaders.The variable decorated with
FragCoordmust be declared using theInputstorage class.The
Centroidinterpolation decoration is ignored, but allowed, onFragCoord.The variable decorated with
FragCoordmust be declared as a four-component vector of 32-bit floating-point values. FragDepth-
Decorating a variable with the
FragDepthbuilt-in decoration will make that variable contain the new depth value for all samples covered by the fragment. This value will be used for depth testing and, if the depth test passes, any subsequent write to the depth/stencil attachment.To write to
FragDepth, a shader must declare theDepthReplacingexecution mode. If a shader declares theDepthReplacingexecution mode and there is an execution path through the shader that does not setFragDepth, then the fragment’s depth value is undefined for executions of the shader that take that path.The
FragDepthdecoration must be used only within fragment shaders.The variable decorated with
FragDepthmust be declared using theOutputstorage class.The variable decorated with
FragDepthmust be declared as a scalar 32-bit floating-point value. FragStencilRefEXT-
Decorating a variable with the
FragStencilRefEXTbuilt-in decoration will make that variable contain the stencil reference value for all samples covered by the fragment. This value will be used as the stencil reference value used in stencil testing.To write to
FragStencilRefEXT, a shader must declare theStencilRefReplacingEXTexecution mode. If a shader declares theStencilRefReplacingEXTexecution mode and there is an execution path through the shader that does not setFragStencilRefEXT, then the fragment’s stencil reference value is undefined for executions of the shader that take that path.The
FragStencilRefEXTdecoration must be used only within fragment shaders.The variable decorated with
FragStencilRefEXTmust be declared using theOutputstorage class.The variable decorated with
FragStencilRefEXTmust be declared as a scalar integer value. Only the least significant s bits of the integer value of the variable decorated withFragStencilRefEXTare considered for stencil testing, where s is the number of bits in the stencil framebuffer attachment, and higher order bits are discarded. FrontFacing-
Decorating a variable with the
FrontFacingbuilt-in decoration will make that variable contain whether the fragment is front or back facing. This variable is non-zero if the current fragment is considered to be part of a front-facing polygon primitive or of a non-polygon primitive and is zero if the fragment is considered to be part of a back-facing polygon primitive.The
FrontFacingdecoration must be used only within fragment shaders.The variable decorated with
FrontFacingmust be declared using theInputstorage class.The variable decorated with
FrontFacingmust be declared as a boolean. FullyCoveredEXT-
Decorating a variable with the
FullyCoveredEXTbuilt-in decoration will make that variable indicate whether the fragment pixel square is fully covered by the generating primitive. This variable is non-zero if conservative rasterization is enabled and the current fragment pixel square is fully covered by the generating primitive, and is zero if the fragment is not covered or partially covered, or conservative rasterization is disabled.The
FullyCoveredEXTdecoration must be used only within fragment shaders and theFragmentFullyCoveredEXTcapability must be declared.The variable decorated with
FullyCoveredEXTmust be declared using theInputstorage class.The variable decorated with
FullyCoveredEXTmust be declared as a boolean.If the implementation supports
VkPhysicalDeviceConservativeRasterizationPropertiesEXT::conservativeRasterizationPostDepthCoverageand thePostDepthCoverageexecution mode is specified theSampleMaskbuilt-in input variable will reflect the coverage after the early per-fragment depth and stencil tests are applied. IfVkPhysicalDeviceConservativeRasterizationPropertiesEXT::conservativeRasterizationPostDepthCoverageis not supported thePostDepthCoverageexecution mode must not be specified. GlobalInvocationId-
Decorating a variable with the
GlobalInvocationIdbuilt-in decoration will make that variable contain the location of the current invocation within the global workgroup. Each component is equal to the index of the local workgroup multiplied by the size of the local workgroup plusLocalInvocationId.The
GlobalInvocationIddecoration must be used only within compute shaders.The variable decorated with
GlobalInvocationIdmust be declared using theInputstorage class.The variable decorated with
GlobalInvocationIdmust be declared as a three-component vector of 32-bit integers. HelperInvocation-
Decorating a variable with the
HelperInvocationbuilt-in decoration will make that variable contain whether the current invocation is a helper invocation. This variable is non-zero if the current fragment being shaded is a helper invocation and zero otherwise. A helper invocation is an invocation of the shader that is produced to satisfy internal requirements such as the generation of derivatives.The
HelperInvocationdecoration must be used only within fragment shaders.The variable decorated with
HelperInvocationmust be declared using theInputstorage class.The variable decorated with
HelperInvocationmust be declared as a boolean.
|
Note
It is very likely that a helper invocation will have a value of
|
InvocationId-
Decorating a variable with the
InvocationIdbuilt-in decoration will make that variable contain the index of the current shader invocation in a geometry shader, or the index of the output patch vertex in a tessellation control shader.In a geometry shader, the index of the current shader invocation ranges from zero to the number of instances declared in the shader minus one. If the instance count of the geometry shader is one or is not specified, then
InvocationIdwill be zero.The
InvocationIddecoration must be used only within tessellation control and geometry shaders.The variable decorated with
InvocationIdmust be declared using theInputstorage class.The variable decorated with
InvocationIdmust be declared as a scalar 32-bit integer. InstanceIndex-
Decorating a variable with the
InstanceIndexbuilt-in decoration will make that variable contain the index of the instance that is being processed by the current vertex shader invocation.InstanceIndexbegins at thefirstInstanceparameter to vkCmdDraw or vkCmdDrawIndexed or at thefirstInstancemember of a structure consumed by vkCmdDrawIndirect or vkCmdDrawIndexedIndirect.The
InstanceIndexdecoration must be used only within vertex shaders.The variable decorated with
InstanceIndexmust be declared using theInputstorage class.The variable decorated with
InstanceIndexmust be declared as a scalar 32-bit integer.
Layer-
Decorating a variable with the
Layerbuilt-in decoration will make that variable contain the select layer of a multi-layer framebuffer attachment.In a vertex, tessellation evaluation, or geometry shader, any variable decorated with
Layercan be written with the framebuffer layer index to which the primitive produced by that shader will be directed.The last active vertex processing stage (in pipeline order) controls the
Layerthat is used. Outputs in previous shader stages are not used, even if the last stage fails to write theLayer.If the last active vertex processing stage shader entry point’s interface does not include a variable decorated with
Layer, then the first layer is used. If a vertex processing stage shader entry point’s interface includes a variable decorated withLayer, it must write the same value toLayerfor all output vertices of a given primitive. If theLayervalue is less than 0 or greater than or equal to the number of layers in the framebuffer, then primitives may still be rasterized, fragment shaders may be executed, and the framebuffer values for all layers are undefined.The
Layerdecoration must be used only within vertex, tessellation evaluation, geometry, and fragment shaders.In a vertex, tessellation evaluation, or geometry shader, any variable decorated with
Layermust be declared using theOutputstorage class. If such a variable is also decorated withViewportRelativeNV, then theViewportIndexis added to the layer that is used for rendering and that is made available in the fragment shader. If the shader writes to a variable decoratedViewportMaskNV, then the layer selected has a different value for each viewport a primitive is rendered to.In a fragment shader, a variable decorated with
Layercontains the layer index of the primitive that the fragment invocation belongs to.In a fragment shader, any variable decorated with
Layermust be declared using theInputstorage class.Any variable decorated with
Layermust be declared as a scalar 32-bit integer. LocalInvocationId-
Decorating a variable with the
LocalInvocationIdbuilt-in decoration will make that variable contain the location of the current compute shader invocation within the local workgroup. Each component ranges from zero through to the size of the workgroup in that dimension minus one.The
LocalInvocationIddecoration must be used only within compute shaders.The variable decorated with
LocalInvocationIdmust be declared using theInputstorage class.The variable decorated with
LocalInvocationIdmust be declared as a three-component vector of 32-bit integers.
|
Note
If the size of the workgroup in a particular dimension is one, then the
|
LocalInvocationIndex-
Decorating a variable with the
LocalInvocationIndexbuilt-in decoration will make that variable contain a one-dimensional representation ofLocalInvocationId. This is computed as:
LocalInvocationIndex =
LocalInvocationId.z * WorkgroupSize.x * WorkgroupSize.y +
LocalInvocationId.y * WorkgroupSize.x +
LocalInvocationId.x;
The LocalInvocationIndex decoration must be used only within compute
shaders.
+
The variable decorated with LocalInvocationIndex must be declared
using the Input storage class.
+
The variable decorated with LocalInvocationIndex must be declared as a
scalar 32-bit integer.
NumSubgroups-
Decorating a variable with the
NumSubgroupsbuilt-in decoration will make that variable contain the number of subgroups in the local workgroup.The
NumSubgroupsdecoration must be used only within compute shaders.The variable decorated with
NumSubgroupsmust be declared using theInputstorage class.The object decorated with
NumSubgroupsmust be declared as a scalar 32-bit integer. NumWorkgroups-
Decorating a variable with the
NumWorkgroupsbuilt-in decoration will make that variable contain the number of local workgroups that are part of the dispatch that the invocation belongs to. Each component is equal to the values of the workgroup count parameters passed into the dispatch commands.The
NumWorkgroupsdecoration must be used only within compute shaders.The variable decorated with
NumWorkgroupsmust be declared using theInputstorage class.The variable decorated with
NumWorkgroupsmust be declared as a three-component vector of 32-bit integers. PatchVertices-
Decorating a variable with the
PatchVerticesbuilt-in decoration will make that variable contain the number of vertices in the input patch being processed by the shader. A single tessellation control or tessellation evaluation shader can read patches of differing sizes, so the value of thePatchVerticesvariable may differ between patches.The
PatchVerticesdecoration must be used only within tessellation control and tessellation evaluation shaders.The variable decorated with
PatchVerticesmust be declared using theInputstorage class.The variable decorated with
PatchVerticesmust be declared as a scalar 32-bit integer. PointCoord-
Decorating a variable with the
PointCoordbuilt-in decoration will make that variable contain the coordinate of the current fragment within the point being rasterized, normalized to the size of the point with origin in the upper left corner of the point, as described in Basic Point Rasterization. If the primitive the fragment shader invocation belongs to is not a point, then the variable decorated withPointCoordcontains an undefined value.The
PointCoorddecoration must be used only within fragment shaders.The variable decorated with
PointCoordmust be declared using theInputstorage class.The variable decorated with
PointCoordmust be declared as two-component vector of 32-bit floating-point values.
|
Note
Depending on how the point is rasterized, |
PointSize-
Decorating a variable with the
PointSizebuilt-in decoration will make that variable contain the size of point primitives. The value written to the variable decorated withPointSizeby the last vertex processing stage in the pipeline is used as the framebuffer-space size of points produced by rasterization.The
PointSizedecoration must be used only within vertex, tessellation control, tessellation evaluation, and geometry shaders.In a vertex shader, any variable decorated with
PointSizemust be declared using theOutputstorage class.In a tessellation control, tessellation evaluation, or geometry shader, any variable decorated with
PointSizemust be declared using either theInputorOutputstorage class.Any variable decorated with
PointSizemust be declared as a scalar 32-bit floating-point value.
|
Note
When |
Position-
Decorating a variable with the
Positionbuilt-in decoration will make that variable contain the position of the current vertex. In the last vertex processing stage, the value of the variable decorated withPositionis used in subsequent primitive assembly, clipping, and rasterization operations.The
Positiondecoration must be used only within vertex, tessellation control, tessellation evaluation, and geometry shaders.In a vertex shader, any variable decorated with
Positionmust be declared using theOutputstorage class.In a tessellation control, tessellation evaluation, or geometry shader, any variable decorated with
Positionmust not be declared in a storage class other thanInputorOutput.Any variable decorated with
Positionmust be declared as a four-component vector of 32-bit floating-point values.
|
Note
When |
PositionPerViewNV-
Decorating a variable with the
PositionPerViewNVbuilt-in decoration will make that variable contain the position of the current vertex, for each view.The
PositionPerViewNVdecoration must be used only within vertex, tessellation control, tessellation evaluation, and geometry shaders.In a vertex shader, any variable decorated with
PositionPerViewNVmust be declared using theOutputstorage class.In a tessellation control, tessellation evaluation, or geometry shader, any variable decorated with
PositionPerViewNVmust not be declared in a storage class other than input or output.Any variable decorated with
PositionPerViewNVmust be declared as an array of four-component vector of 32-bit floating-point values with at least as many elements as the maximum view in the subpass’s view mask plus one. The array must be indexed by a constant or specialization constant.Elements of the array correspond to views in a multiview subpass, and those elements corresponding to views in the view mask of the subpass the shader is compiled against will be used as the position value for those views. For the final vertex processing stage in the pipeline, values written to an output variable decorated with
PositionPerViewNVare used in subsequent primitive assembly, clipping, and rasterization operations, as withPosition.PositionPerViewNVoutput in an earlier vertex processing stage is available as an input in the subsequent vertex processing stage.If a shader is compiled against a subpass that has the
VK_SUBPASS_DESCRIPTION_PER_VIEW_POSITION_X_ONLY_BIT_NVXbit set, then the position values for each view must not differ in any component other than the X component. If the values do differ, one will be chosen in an implementation-dependent manner. PrimitiveId-
Decorating a variable with the
PrimitiveIdbuilt-in decoration will make that variable contain the index of the current primitive.The index of the first primitive generated by a drawing command is zero, and the index is incremented after every individual point, line, or triangle primitive is processed.
For triangles drawn as points or line segments (see Polygon Mode), the primitive index is incremented only once, even if multiple points or lines are eventually drawn.
Variables decorated with
PrimitiveIdare reset to zero between each instance drawn.Restarting a primitive topology using primitive restart has no effect on the value of variables decorated with
PrimitiveId.In tessellation control and tessellation evaluation shaders, it will contain the index of the patch within the current set of rendering primitives that correspond to the shader invocation.
In a geometry shader, it will contain the number of primitives presented as input to the shader since the current set of rendering primitives was started.
In a fragment shader, it will contain the primitive index written by the geometry shader if a geometry shader is present, or with the value that would have been presented as input to the geometry shader had it been present.
If a geometry shader is present and the fragment shader reads from an input variable decorated with
PrimitiveId, then the geometry shader must write to an output variable decorated withPrimitiveIdin all execution paths.The
PrimitiveIddecoration must be used only within fragment, tessellation control, tessellation evaluation, and geometry shaders.In a tessellation control or tessellation evaluation shader, any variable decorated with
PrimitiveIdmust be declared using theInputstorage class.In a geometry shader, any variable decorated with
PrimitiveIdmust be declared using either theInputorOutputstorage class.In a fragment shader, any variable decorated with
PrimitiveIdmust be declared using theInputstorage class, and either theGeometryorTessellationcapability must also be declared.Any variable decorated with
PrimitiveIdmust be declared as a scalar 32-bit integer.
|
Note
When the |
SampleId-
Decorating a variable with the
SampleIdbuilt-in decoration will make that variable contain the zero-based index of the sample the invocation corresponds to.SampleIdranges from zero to the number of samples in the framebuffer minus one. If a fragment shader entry point’s interface includes an input variable decorated withSampleId, Sample Shading is considered enabled with aminSampleShadingvalue of 1.0.The
SampleIddecoration must be used only within fragment shaders.The variable decorated with
SampleIdmust be declared using theInputstorage class.The variable decorated with
SampleIdmust be declared as a scalar 32-bit integer.
SampleMask-
Decorating a variable with the
SampleMaskbuilt-in decoration will make any variable contain the sample coverage mask for the current fragment shader invocation.A variable in the
Inputstorage class decorated withSampleMaskwill contain a bitmask of the set of samples covered by the primitive generating the fragment during rasterization. It has a sample bit set if and only if the sample is considered covered for this fragment shader invocation.SampleMask[] is an array of integers. Bits are mapped to samples in a manner where bit B of mask M (SampleMask[M]) corresponds to sample 32 × M + B.When state specifies multiple fragment shader invocations for a given fragment, the sample mask for any single fragment shader invocation specifies the subset of the covered samples for the fragment that correspond to the invocation. In this case, the bit corresponding to each covered sample will be set in exactly one fragment shader invocation.
If the
PostDepthCoverageexecution mode is specified, the sample is considered covered if and only if the sample is covered by the primitive and the sample passes the early per-fragment tests. Otherwise the sample is considered covered if the sample is covered by the primitive, regardless of the result of the fragment tests.A variable in the
Outputstorage class decorated withSampleMaskis an array of integers forming a bit array in a manner similar an input variable decorated withSampleMask, but where each bit represents coverage as computed by the shader. Modifying the sample mask by writing zero to a bit ofSampleMaskcauses the sample to be considered uncovered. If this variable is also decorated withOverrideCoverageNV, the fragment coverage is replaced with the sample mask bits set in the shader otherwise the fragment coverage isANDedwith the bits of the sample mask. If the fragment shader is being evaluated at any frequency other than per-fragment, bits of the sample mask not corresponding to the current fragment shader invocation are ignored. This array must be sized in the fragment shader either implicitly or explicitly, to be no larger than the implementation-dependent maximum sample-mask (as an array of 32-bit elements), determined by the maximum number of samples. If a fragment shader entry point’s interface includes an output variable decorated withSampleMask, the sample mask will be undefined for any array elements of any fragment shader invocations that fail to assign a value. If a fragment shader entry point’s interface does not include an output variable decorated withSampleMask, the sample mask has no effect on the processing of a fragment.The
SampleMaskdecoration must be used only within fragment shaders.Any variable decorated with
SampleMaskmust be declared using either theInputorOutputstorage class.Any variable decorated with
SampleMaskmust be declared as an array of 32-bit integers. SamplePosition-
Decorating a variable with the
SamplePositionbuilt-in decoration will make that variable contain the sub-pixel position of the sample being shaded. The top left of the pixel is considered to be at coordinate (0,0) and the bottom right of the pixel is considered to be at coordinate (1,1). If a fragment shader entry point’s interface includes an input variable decorated withSamplePosition, Sample Shading is considered enabled with aminSampleShadingvalue of 1.0.The
SamplePositiondecoration must be used only within fragment shaders.The variable decorated with
SamplePositionmust be declared using theInputstorage class. If the current pipeline uses custom sample locations the value of any variable decorated with theSamplePositionbuilt-in decoration is undefined.The variable decorated with
SamplePositionmust be declared as a two-component vector of 32-bit floating-point values. SubgroupId-
Decorating a variable with the
SubgroupIdbuilt-in decoration will make that variable contain the index of the subgroup within the local workgroup. This variable is in range [0,NumSubgroups-1].The
SubgroupIddecoration must be used only within compute shaders.The variable decorated with
SubgroupIdmust be declared using theInputstorage class.The variable decorated with
SubgroupIdmust be declared as a scalar 32-bit integer.
SubgroupEqMask-
Decorating a variable with the
SubgroupEqMaskbuiltin decoration will make that variable contain the subgroup mask of the current subgroup invocation. The bit corresponding to theSubgroupLocalInvocationIdis set in the variable decorated withSubgroupEqMask. All other bits are set to zero.The variable decorated with
SubgroupEqMaskmust be declared using theInputstorage class.The variable decorated with
SubgroupEqMaskmust be declared as a four-component vector of 32-bit integer values.SubgroupEqMaskKHRis an alias ofSubgroupEqMask.
SubgroupGeMask-
Decorating a variable with the
SubgroupGeMaskbuiltin decoration will make that variable contain the subgroup mask of the current subgroup invocation. The bits corresponding to the invocations greater than or equal toSubgroupLocalInvocationIdthroughSubgroupSize-1 are set in the variable decorated withSubgroupGeMask. All other bits are set to zero.The variable decorated with
SubgroupGeMaskmust be declared using theInputstorage class.The variable decorated with
SubgroupGeMaskmust be declared as a four-component vector of 32-bit integer values.SubgroupGeMaskKHRis an alias ofSubgroupGeMask.
SubgroupGtMask-
Decorating a variable with the
SubgroupGtMaskbuiltin decoration will make that variable contain the subgroup mask of the current subgroup invocation. The bits corresponding to the invocations greater thanSubgroupLocalInvocationIdthroughSubgroupSize-1 are set in the variable decorated withSubgroupGtMask. All other bits are set to zero.The variable decorated with
SubgroupGtMaskmust be declared using theInputstorage class.The variable decorated with
SubgroupGtMaskmust be declared as a four-component vector of 32-bit integer values.SubgroupGtMaskKHRis an alias ofSubgroupGtMask.
SubgroupLeMask-
Decorating a variable with the
SubgroupLeMaskbuiltin decoration will make that variable contain the subgroup mask of the current subgroup invocation. The bits corresponding to the invocations less than or equal toSubgroupLocalInvocationIdare set in the variable decorated withSubgroupLeMask. All other bits are set to zero.The variable decorated with
SubgroupLeMaskmust be declared using theInputstorage class.The variable decorated with
SubgroupLeMaskmust be declared as a four-component vector of 32-bit integer values.SubgroupLeMaskKHRis an alias ofSubgroupLeMask.
SubgroupLtMask-
Decorating a variable with the
SubgroupLtMaskbuiltin decoration will make that variable contain the subgroup mask of the current subgroup invocation. The bits corresponding to the invocations less thanSubgroupLocalInvocationIdare set in the variable decorated withSubgroupLtMask. All other bits are set to zero.The variable decorated with
SubgroupLtMaskmust be declared using theInputstorage class.The variable decorated with
SubgroupLtMaskmust be declared as a four-component vector of 32-bit integer values.SubgroupLtMaskKHRis an alias ofSubgroupLtMask.
SubgroupLocalInvocationId-
Decorating a variable with the
SubgroupLocalInvocationIdbuiltin decoration will make that variable contain the index of the invocation within the subgroup. This variable is in range [0,SubgroupSize-1].The variable decorated with
SubgroupLocalInvocationIdmust be declared using theInputstorage class.The variable decorated with
SubgroupLocalInvocationIdmust be declared as a scalar 32-bit integer.
SubgroupSize-
Decorating a variable with the
SubgroupSizebuiltin decoration will make that variable contain the implementation-dependent maximum number of invocations in a subgroup. The maximum number of invocations that an implementation can support per subgroup is 128.The variable decorated with
SubgroupSizemust be declared using theInputstorage class.The variable decorated with
SubgroupSizemust be declared as a scalar 32-bit integer. TessCoord-
Decorating a variable with the
TessCoordbuilt-in decoration will make that variable contain the three-dimensional (u,v,w) barycentric coordinate of the tessellated vertex within the patch. u, v, and w are in the range [0,1] and vary linearly across the primitive being subdivided. For the tessellation modes ofQuadsorIsoLines, the third component is always zero.The
TessCoorddecoration must be used only within tessellation evaluation shaders.The variable decorated with
TessCoordmust be declared using theInputstorage class.The variable decorated with
TessCoordmust be declared as three-component vector of 32-bit floating-point values. TessLevelOuter-
Decorating a variable with the
TessLevelOuterbuilt-in decoration will make that variable contain the outer tessellation levels for the current patch.In tessellation control shaders, the variable decorated with
TessLevelOutercan be written to which controls the tessellation factors for the resulting patch. These values are used by the tessellator to control primitive tessellation and can be read by tessellation evaluation shaders.In tessellation evaluation shaders, the variable decorated with
TessLevelOutercan read the values written by the tessellation control shader.The
TessLevelOuterdecoration must be used only within tessellation control and tessellation evaluation shaders.In a tessellation control shader, any variable decorated with
TessLevelOutermust be declared using theOutputstorage class.In a tessellation evaluation shader, any variable decorated with
TessLevelOutermust be declared using theInputstorage class.Any variable decorated with
TessLevelOutermust be declared as an array of size four, containing 32-bit floating-point values. TessLevelInner-
Decorating a variable with the
TessLevelInnerbuilt-in decoration will make that variable contain the inner tessellation levels for the current patch.In tessellation control shaders, the variable decorated with
TessLevelInnercan be written to, which controls the tessellation factors for the resulting patch. These values are used by the tessellator to control primitive tessellation and can be read by tessellation evaluation shaders.In tessellation evaluation shaders, the variable decorated with
TessLevelInnercan read the values written by the tessellation control shader.The
TessLevelInnerdecoration must be used only within tessellation control and tessellation evaluation shaders.In a tessellation control shader, any variable decorated with
TessLevelInnermust be declared using theOutputstorage class.In a tessellation evaluation shader, any variable decorated with
TessLevelInnermust be declared using theInputstorage class.Any variable decorated with
TessLevelInnermust be declared as an array of size two, containing 32-bit floating-point values. VertexIndex-
Decorating a variable with the
VertexIndexbuilt-in decoration will make that variable contain the index of the vertex that is being processed by the current vertex shader invocation. For non-indexed draws, this variable begins at thefirstVertexparameter to vkCmdDraw or thefirstVertexmember of a structure consumed by vkCmdDrawIndirect and increments by one for each vertex in the draw. For indexed draws, its value is the content of the index buffer for the vertex plus thevertexOffsetparameter to vkCmdDrawIndexed or thevertexOffsetmember of the structure consumed by vkCmdDrawIndexedIndirect.The
VertexIndexdecoration must be used only within vertex shaders.The variable decorated with
VertexIndexmust be declared using theInputstorage class.The variable decorated with
VertexIndexmust be declared as a scalar 32-bit integer.
|
Note
|
ViewIndex-
The
ViewIndexdecoration can be applied to a shader input which will be filled with the index of the view that is being processed by the current shader invocation.If multiview is enabled in the render pass, this value will be one of the bits set in the view mask of the subpass the pipeline is compiled against. If multiview is not enabled in the render pass, this value will be zero.
The
ViewIndexdecoration must not be used within compute shaders.The variable decorated with
ViewIndexmust be declared using theInputstorage class.The variable decorated with
ViewIndexmust be declared as a scalar 32-bit integer.
ViewportIndex-
Decorating a variable with the
ViewportIndexbuilt-in decoration will make that variable contain the index of the viewport.In a vertex, tessellation evaluation, or geometry shader, the variable decorated with
ViewportIndexcan be written to with the viewport index to which the primitive produced by that shader will be directed.The selected viewport index is used to select the viewport transform and scissor rectangle.
The last active vertex processing stage (in pipeline order) controls the
ViewportIndexthat is used. Outputs in previous shader stages are not used, even if the last stage fails to write theViewportIndex.If the last active vertex processing stage shader entry point’s interface does not include a variable decorated with
ViewportIndex, then the first viewport is used. If a vertex processing stage shader entry point’s interface includes a variable decorated withViewportIndex, it must write the same value toViewportIndexfor all output vertices of a given primitive.The
ViewportIndexdecoration must be used only within vertex, tessellation evaluation, geometry, and fragment shaders.In a vertex, tessellation evaluation, or geometry shader, any variable decorated with
ViewportIndexmust be declared using theOutputstorage class.In a fragment shader, the variable decorated with
ViewportIndexcontains the viewport index of the primitive that the fragment invocation belongs to.In a fragment shader, any variable decorated with
ViewportIndexmust be declared using theInputstorage class.Any variable decorated with
ViewportIndexmust be declared as a scalar 32-bit integer.
ViewportMaskNV-
Decorating a variable with the
ViewportMaskNVbuilt-in decoration will make that variable contain the viewport mask.In a vertex, tessellation evaluation, or geometry shader, the variable decorated with
ViewportMaskNVcan be written to with the mask of which viewports the primitive produced by that shader will directed.The
ViewportMaskNVvariable must be an array that has ⌈(VkPhysicalDeviceLimits::maxViewports/ 32)⌉ elements. When a shader writes to this variable, bit B of element M controls whether a primitive is emitted to viewport 32 × M +B. The viewports indicated by the mask are used to select the viewport transform and scissor rectangle that a primitive will be transformed by.The last active vertex processing stage (in pipeline order) controls the
ViewportMaskNVthat is used. Outputs in previous shader stages are not used, even if the last stage fails to write theViewportMaskNV. WhenViewportMaskNVis written by the final vertex processing stage, any variable decorated withViewportIndexin the fragment shader will have the index of the viewport that was used in generating that fragment.If a vertex processing stage shader entry point’s interface includes a variable decorated with
ViewportMaskNV, it must write the same value toViewportMaskNVfor all output vertices of a given primitive.The
ViewportMaskNVdecoration must be used only within vertex, tessellation evaluation, and geometry shaders.Any variable decorated with
ViewportMaskNVmust be declared using theOutputstorage class.Any variable decorated with
ViewportMaskNVmust be declared as an array of 32-bit integers.
ViewportMaskPerViewNV-
Decorating a variable with the
ViewportMaskPerViewNVbuilt-in decoration will make that variable contain the mask of viewports primitives are broadcast to, for each view.The
ViewportMaskPerViewNVdecoration must be used only within vertex, tessellation control, tessellation evaluation, and geometry shaders.Any variable decorated with
ViewportMaskPerViewNVmust be declared using theOutputstorage class.The value written to an element of
ViewportMaskPerViewNVin the last vertex processing stage is a bitmask indicating which viewports the primitive will be directed to. The primitive will be broadcast to the viewport corresponding to each non-zero bit of the bitmask, and that viewport index is used to select the viewport transform and scissor rectangle, for each view. The same values must be written to all vertices in a given primitive, or else the set of viewports used for that primitive is undefined.Any variable decorated with
ViewportMaskPerViewNVmust be declared as an array of scalar 32-bit integers with at least as many elements as the maximum view in the subpass’s view mask plus one. The array must be indexed by a constant or specialization constant.Elements of the array correspond to views in a multiview subpass, and those elements corresponding to views in the view mask of the subpass the shader is compiled against will be used as the viewport mask value for those views.
ViewportMaskPerViewNVoutput in an earlier vertex processing stage is not available as an input in the subsequent vertex processing stage.Although
ViewportMaskNVis an array,ViewportMaskPerViewNVis not a two-dimensional array. Instead,ViewportMaskPerViewNVis limited to 32 viewports. WorkgroupId-
Decorating a variable with the
WorkgroupIdbuilt-in decoration will make that variable contain the global workgroup that the current invocation is a member of. Each component ranges from a base value to a base + count value, based on the parameters passed into the dispatch commands.The
WorkgroupIddecoration must be used only within compute shaders.The variable decorated with
WorkgroupIdmust be declared using theInputstorage class.The variable decorated with
WorkgroupIdmust be declared as a three-component vector of 32-bit integers. WorkgroupSize-
Decorating an object with the
WorkgroupSizebuilt-in decoration will make that object contain the dimensions of a local workgroup. If an object is decorated with theWorkgroupSizedecoration, this must take precedence over any execution mode set forLocalSize.The
WorkgroupSizedecoration must be used only within compute shaders.The object decorated with
WorkgroupSizemust be a specialization constant or a constant.The object decorated with
WorkgroupSizemust be declared as a three-component vector of 32-bit integers.
15. Image Operations
15.1. Image Operations Overview
Image Operations are steps performed by SPIR-V image instructions, where
those instructions which take an OpTypeImage (representing a
VkImageView) or OpTypeSampledImage (representing a
(VkImageView, VkSampler) pair) and texel coordinates as
operands, and return a value based on one or more neighboring texture
elements (texels) in the image.
|
Note
Texel is a term which is a combination of the words texture and element. Early interactive computer graphics supported texture operations on textures, a small subset of the image operations on images described here. The discrete samples remain essentially equivalent, however, so we retain the historical term texel to refer to them. |
SPIR-V Image Instructions include the following functionality:
-
OpImageSample* andOpImageSparseSample* read one or more neighboring texels of the image, and filter the texel values based on the state of the sampler.-
Instructions with
ImplicitLodin the name determine the LOD used in the sampling operation based on the coordinates used in neighboring fragments. -
Instructions with
ExplicitLodin the name determine the LOD used in the sampling operation based on additional coordinates. -
Instructions with
Projin the name apply homogeneous projection to the coordinates.
-
-
OpImageFetchandOpImageSparseFetchreturn a single texel of the image. No sampler is used. -
OpImage*GatherandOpImageSparse*Gatherread neighboring texels and return a single component of each. -
OpImageRead(andOpImageSparseRead) andOpImageWriteread and write, respectively, a texel in the image. No sampler is used. -
Instructions with
Drefin the name apply depth comparison on the texel values. -
Instructions with
Sparsein the name additionally return a sparse residency code.
15.1.1. Texel Coordinate Systems
Images are addressed by texel coordinates. There are three texel coordinate systems:
-
normalized texel coordinates [0.0, 1.0]
-
unnormalized texel coordinates [0.0, width / height / depth)
-
integer texel coordinates [0, width / height / depth)
SPIR-V OpImageFetch, OpImageSparseFetch, OpImageRead,
OpImageSparseRead, and OpImageWrite instructions use integer texel
coordinates.
Other image instructions can use either normalized or unnormalized texel
coordinates (selected by the unnormalizedCoordinates state of the
sampler used in the instruction), but there are
limitations on what operations, image
state, and sampler state is supported.
Normalized coordinates are logically
converted to unnormalized as part of
image operations, and certain steps are
only performed on normalized coordinates.
The array layer coordinate is always treated as unnormalized even when other
coordinates are normalized.
Normalized texel coordinates are referred to as (s,t,r,q,a), with the coordinates having the following meanings:
-
s: Coordinate in the first dimension of an image.
-
t: Coordinate in the second dimension of an image.
-
r: Coordinate in the third dimension of an image.
-
(s,t,r) are interpreted as a direction vector for Cube images.
-
-
q: Fourth coordinate, for homogeneous (projective) coordinates.
-
a: Coordinate for array layer.
The coordinates are extracted from the SPIR-V operand based on the
dimensionality of the image variable and type of instruction.
For Proj instructions, the components are in order (s, [t,] [r,] q)
with t and r being conditionally present based on the Dim of the image.
For non-Proj instructions, the coordinates are (s [,t] [,r] [,a]), with
t and r being conditionally present based on the Dim of the image and a
being conditionally present based on the Arrayed property of the image.
Projective image instructions are not supported on Arrayed images.
Unnormalized texel coordinates are referred to as (u,v,w,a), with the coordinates having the following meanings:
-
u: Coordinate in the first dimension of an image.
-
v: Coordinate in the second dimension of an image.
-
w: Coordinate in the third dimension of an image.
-
a: Coordinate for array layer.
Only the u and v coordinates are directly extracted from the
SPIR-V operand, because only 1D and 2D (non-Arrayed) dimensionalities
support unnormalized coordinates.
The components are in order (u [,v]), with v being conditionally
present when the dimensionality is 2D.
When normalized coordinates are converted to unnormalized coordinates, all
four coordinates are used.
Integer texel coordinates are referred to as (i,j,k,l,n), and the
first four in that order have the same meanings as unnormalized texel
coordinates.
They are extracted from the SPIR-V operand in order (i, [,j], [,k],
[,l]), with j and k conditionally present based on the Dim
of the image, and l conditionally present based on the Arrayed property
of the image.
n is the sample index and is taken from the Sample image operand.
For all coordinate types, unused coordinates are assigned a value of zero.
The Texel Coordinate Systems - For the example shown of an 8×4 texel two dimensional image.
-
Normalized texel coordinates:
-
The s coordinate goes from 0.0 to 1.0, left to right.
-
The t coordinate goes from 0.0 to 1.0, top to bottom.
-
-
Unnormalized texel coordinates:
-
The u coordinate goes from -1.0 to 9.0, left to right. The u coordinate within the range 0.0 to 8.0 is within the image, otherwise it is within the border.
-
The v coordinate goes from -1.0 to 5.0, top to bottom. The v coordinate within the range 0.0 to 4.0 is within the image, otherwise it is within the border.
-
-
Integer texel coordinates:
-
The i coordinate goes from -1 to 8, left to right. The i coordinate within the range 0 to 7 addresses texels within the image, otherwise it addresses a border texel.
-
The j coordinate goes from -1 to 5, top to bottom. The j coordinate within the range 0 to 3 addresses texels within the image, otherwise it addresses a border texel.
-
-
Also shown for linear filtering:
-
Given the unnormalized coordinates (u,v), the four texels selected are i0j0, i1j0, i0j1, and i1j1.
-
The weights α and β.
-
Given the offset Δi and Δj, the four texels selected by the offset are i0j'0, i1j'0, i0j'1, and i1j'1.
-
|
Note
For formats with reduced-resolution channels, Δi and Δj are relative to the resolution of the highest-resolution channel, and therefore may be divided by two relative to the unnormalized coordinate space of the lower-resolution channels. |
The Texel Coordinate Systems - For the example shown of an 8×4 texel two dimensional image.
-
Texel coordinates as above. Also shown for nearest filtering:
-
Given the unnormalized coordinates (u,v), the texel selected is ij.
-
Given the offset Δi and Δj, the texel selected by the offset is ij'.
-
15.2. Conversion Formulas
|
editing-note
(Bill) These Conversion Formulas will likely move to Section 2.7 Fixed-Point Data Conversions (RGB to sRGB and sRGB to RGB) and section 2.6 Numeric Representation and Computation (RGB to Shared Exponent and Shared Exponent to RGB) |
15.2.1. RGB to Shared Exponent Conversion
An RGB color (red, green, blue) is transformed to a shared exponent color (redshared, greenshared, blueshared, expshared) as follows:
First, the components (red, green, blue) are clamped to (redclamped, greenclamped, blueclamped) as:
-
redclamped = max(0, min(sharedexpmax, red))
-
greenclamped = max(0, min(sharedexpmax, green))
-
blueclamped = max(0, min(sharedexpmax, blue))
Where:
|
Note
NaN, if supported, is handled as in IEEE 754-2008
|
The largest clamped component, maxclamped is determined:
-
maxclamped = max(redclamped, greenclamped, blueclamped)
A preliminary shared exponent exp' is computed:
The shared exponent expshared is computed:
Finally, three integer values in the range 0 to 2N are computed:
15.2.2. Shared Exponent to RGB
A shared exponent color (redshared, greenshared, blueshared, expshared) is transformed to an RGB color (red, green, blue) as follows:
-
\(red = red_{shared} \times {2^{(exp_{shared}-B-N)}}\)
-
\(green = green_{shared} \times {2^{(exp_{shared}-B-N)}}\)
-
\(blue = blue_{shared} \times {2^{(exp_{shared}-B-N)}}\)
Where:
-
N = 9 (number of mantissa bits per component)
-
B = 15 (exponent bias)
15.3. Texel Input Operations
Texel input instructions are SPIR-V image instructions that read from an image. Texel input operations are a set of steps that are performed on state, coordinates, and texel values while processing a texel input instruction, and which are common to some or all texel input instructions. They include the following steps, which are performed in the listed order:
For texel input instructions involving multiple texels (for sampling or gathering), these steps are applied for each texel that is used in the instruction. Depending on the type of image instruction, other steps are conditionally performed between these steps or involving multiple coordinate or texel values.
If Chroma Reconstruction is implicit, Texel Filtering instead takes place during chroma reconstruction, before sampler Y’CBCR conversion occurs.
15.3.1. Texel Input Validation Operations
Texel input validation operations inspect instruction/image/sampler state or coordinates, and in certain circumstances cause the texel value to be replaced or become undefined. There are a series of validations that the texel undergoes.
Instruction/Sampler/Image View Validation
There are a number of cases where a SPIR-V instruction can mismatch with the sampler, the image view, or both. There are a number of cases where the sampler can mismatch with the image view. In such cases the value of the texel returned is undefined.
These cases include:
-
The sampler
borderColoris an integer type and the image viewformatis not one of the VkFormat integer types or a stencil component of a depth/stencil format. -
The sampler
borderColoris a float type and the image viewformatis not one of the VkFormat float types or a depth component of a depth/stencil format. -
The sampler
borderColoris one of the opaque black colors (VK_BORDER_COLOR_FLOAT_OPAQUE_BLACKorVK_BORDER_COLOR_INT_OPAQUE_BLACK) and the image view VkComponentSwizzle for any of the VkComponentMapping components is notVK_COMPONENT_SWIZZLE_IDENTITY. -
The VkImageLayout of any subresource in the image view does not match that specified in VkDescriptorImageInfo::
imageLayoutused to write the image descriptor. -
If the instruction is
OpImageReadorOpImageSparseReadand theshaderStorageImageReadWithoutFormatfeature is not enabled, or the instruction isOpImageWriteand theshaderStorageImageWriteWithoutFormatfeature is not enabled, then the SPIR-V Image Format must be compatible with the image view’sformat. -
The sampler
unnormalizedCoordinatesisVK_TRUEand any of the limitations of unnormalized coordinates are violated. -
The SPIR-V instruction is one of the
OpImage*Dref* instructions and the samplercompareEnableisVK_FALSE -
The SPIR-V instruction is not one of the
OpImage*Dref* instructions and the samplercompareEnableisVK_TRUE -
The SPIR-V instruction is one of the
OpImage*Dref* instructions and the image viewformatis not one of the depth/stencil formats with a depth component, or the image view aspect is notVK_IMAGE_ASPECT_DEPTH_BIT. -
The SPIR-V instruction’s image variable’s properties are not compatible with the image view:
-
Rules for
viewType:-
VK_IMAGE_VIEW_TYPE_1Dmust haveDim= 1D,Arrayed= 0,MS= 0. -
VK_IMAGE_VIEW_TYPE_2Dmust haveDim= 2D,Arrayed= 0. -
VK_IMAGE_VIEW_TYPE_3Dmust haveDim= 3D,Arrayed= 0,MS= 0. -
VK_IMAGE_VIEW_TYPE_CUBEmust haveDim= Cube,Arrayed= 0,MS= 0. -
VK_IMAGE_VIEW_TYPE_1D_ARRAYmust haveDim= 1D,Arrayed= 1,MS= 0. -
VK_IMAGE_VIEW_TYPE_2D_ARRAYmust haveDim= 2D,Arrayed= 1. -
VK_IMAGE_VIEW_TYPE_CUBE_ARRAYmust haveDim= Cube,Arrayed= 1,MS= 0.
-
-
If the image was created with VkImageCreateInfo::
samplesequal toVK_SAMPLE_COUNT_1_BIT, the instruction must haveMS= 0. -
If the image was created with VkImageCreateInfo::
samplesnot equal toVK_SAMPLE_COUNT_1_BIT, the instruction must haveMS= 1.
-
Only OpImageSample* and OpImageSparseSample* can be used with a
sampler that enables sampler Y’CBCR
conversion.
OpImageFetch, OpImageSparseFetch, OpImage*Gather, and
OpImageSparse*Gather must not be used with a sampler that enables
sampler Y'CBCR conversion.
The ConstOffset and Offset operands must not be used with a
sampler that enables sampler Y’CBCR
conversion.
Integer Texel Coordinate Validation
Integer texel coordinates are validated against the size of the image level, and the number of layers and number of samples in the image. For SPIR-V instructions that use integer texel coordinates, this is performed directly on the integer coordinates. For instructions that use normalized or unnormalized texel coordinates, this is performed on the coordinates that result after conversion to integer texel coordinates.
If the integer texel coordinates do not satisfy all of the conditions
-
0 ≤ i < ws
-
0 ≤ j < hs
-
0 ≤ k < ds
-
0 ≤ l < layers
-
0 ≤ n < samples
where:
-
ws = width of the image level
-
hs = height of the image level
-
ds = depth of the image level
-
layers = number of layers in the image
-
samples = number of samples per texel in the image
then the texel fails integer texel coordinate validation.
There are four cases to consider:
-
Valid Texel Coordinates
-
If the texel coordinates pass validation (that is, the coordinates lie within the image),
then the texel value comes from the value in image memory.
-
-
Border Texel
-
If the texel coordinates fail validation, and
-
If the read is the result of an image sample instruction or image gather instruction, and
-
If the image is not a cube image,
then the texel is a border texel and texel replacement is performed.
-
-
Invalid Texel
-
If the texel coordinates fail validation, and
-
If the read is the result of an image fetch instruction, image read instruction, or atomic instruction,
then the texel is an invalid texel and texel replacement is performed.
-
-
Cube Map Edge or Corner
Otherwise the texel coordinates lie on the borders along the edges and corners of a cube map image, and Cube map edge handling is performed.
Cube Map Edge Handling
If the texel coordinates lie on the borders along the edges and corners of a
cube map image, the following steps are performed.
Note that this only occurs when using VK_FILTER_LINEAR filtering
within a mip level, since VK_FILTER_NEAREST is treated as using
VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE.
-
Cube Map Edge Texel
-
If the texel lies along the border in either only i or only j
then the texel lies along an edge, so the coordinates (i,j) and the array layer l are transformed to select the adjacent texel from the appropriate neighboring face.
-
-
Cube Map Corner Texel
-
If the texel lies along the border in both i and j
then the texel lies at a corner and there is no unique neighboring face from which to read that texel. The texel should be replaced by the average of the three values of the adjacent texels in each incident face. However, implementations may replace the cube map corner texel by other methods, subject to the constraint that if the three available samples have the same value, the replacement texel also has that value.
-
Sparse Validation
If the texel reads from an unbound region of a sparse image, the texel is a sparse unbound texel, and processing continues with texel replacement.
Layout Validation
If all planes of a disjoint multi-planar image are not in the same image layout when the image is sampled with sampler Y’CBCR conversion, the result of texel reads is undefined.
15.3.2. Format Conversion
Texels undergo a format conversion from the VkFormat of the image view to a vector of either floating point or signed or unsigned integer components, with the number of components based on the number of components present in the format.
-
Color formats have one, two, three, or four components, according to the format.
-
Depth/stencil formats are one component. The depth or stencil component is selected by the
aspectMaskof the image view.
Each component is converted based on its type and size (as defined in the Format Definition section for each VkFormat), using the appropriate equations in 16-Bit Floating-Point Numbers, Unsigned 11-Bit Floating-Point Numbers, Unsigned 10-Bit Floating-Point Numbers, Fixed-Point Data Conversion, and Shared Exponent to RGB. Signed integer components smaller than 32 bits are sign-extended.
If the image format is sRGB, the color components are first converted as if they are UNORM, and then sRGB to linear conversion is applied to the R, G, and B components as described in the “sRGB EOTF” section of the Khronos Data Format Specification. The A component, if present, is unchanged.
If the image view format is block-compressed, then the texel value is first decoded, then converted based on the type and number of components defined by the compressed format.
15.3.3. Texel Replacement
A texel is replaced if it is one (and only one) of:
-
a border texel,
-
an invalid texel, or
-
a sparse unbound texel.
Border texels are replaced with a value based on the image format and the
borderColor of the sampler.
The border color is:
Sampler borderColor |
Corresponding Border Color |
|---|---|
|
B = (0.0, 0.0, 0.0, 0.0) |
|
B = (0.0, 0.0, 0.0, 1.0) |
|
B = (1.0, 1.0, 1.0, 1.0) |
|
B = (0, 0, 0, 0) |
|
B = (0, 0, 0, 1) |
|
B = (1, 1, 1, 1) |
|
Note
The names |
This is substituted for the texel value by replacing the number of components in the image format
| Texel Aspect or Format | Component Assignment |
|---|---|
Depth aspect |
D = Br |
Stencil aspect |
S = Br |
One component color format |
Cr = Br |
Two component color format |
Crg = (Br,Bg) |
Three component color format |
Crgb = (Br,Bg,Bb) |
Four component color format |
Crgba = (Br,Bg,Bb,Ba) |
The value returned by a read of an invalid texel is undefined, unless that
read operation is from a buffer resource and the robustBufferAccess
feature is enabled.
In that case, an invalid texel is replaced as described by the
robustBufferAccess feature.
If the
VkPhysicalDeviceSparseProperties::residencyNonResidentStrict
property is VK_TRUE, a sparse unbound texel is replaced with 0 or 0.0
values for integer and floating-point components of the image format,
respectively.
If residencyNonResidentStrict is VK_FALSE, the value of the
sparse unbound texel is undefined.
15.3.4. Depth Compare Operation
If the image view has a depth/stencil format, the depth component is
selected by the aspectMask, and the operation is a Dref
instruction, a depth comparison is performed.
The value of the result D is 1.0 if the result of the compare
operation is true, and 0.0 otherwise.
The compare operation is selected by the compareOp member of the
sampler.
where, in the depth comparison:
-
Dref = shaderOp.Dref (from optional SPIR-V operand)
-
D (texel depth value)
15.3.5. Conversion to RGBA
The texel is expanded from one, two, or three to four components based on the image base color:
| Texel Aspect or Format | RGBA Color |
|---|---|
Depth aspect |
Crgba = (D,0,0,one) |
Stencil aspect |
Crgba = (S,0,0,one) |
One component color format |
Crgba = (Cr,0,0,one) |
Two component color format |
Crgba = (Crg,0,one) |
Three component color format |
Crgba = (Crgb,one) |
Four component color format |
Crgba = Crgba |
where one = 1.0f for floating-point formats and depth aspects, and one = 1 for integer formats and stencil aspects.
15.3.6. Component Swizzle
All texel input instructions apply a swizzle based on:
-
the VkComponentSwizzle enums in the
componentsmember of the VkImageViewCreateInfo structure for the image being read if sampler Y’CBCR conversion is not enabled, and -
the VkComponentSwizzle enums in the
componentsmember of the VkSamplerYcbcrConversionCreateInfo structure for the sampler Y’CBCR conversion if sampler Y’CBCR conversion is enabled.
The swizzle can rearrange the components of the texel, or substitute zero and one for any components. It is defined as follows for the R component, and operates similarly for the other components.
where:
For each component this is applied to, the
VK_COMPONENT_SWIZZLE_IDENTITY swizzle selects the corresponding
component from Crgba.
If the border color is one of the VK_BORDER_COLOR_*_OPAQUE_BLACK enums
and the VkComponentSwizzle is not VK_COMPONENT_SWIZZLE_IDENTITY
for all components (or the
equivalent identity mapping),
the value of the texel after swizzle is undefined.
15.3.7. Sparse Residency
OpImageSparse* instructions return a structure which includes a
residency code indicating whether any texels accessed by the instruction
are sparse unbound texels.
This code can be interpreted by the OpImageSparseTexelsResident
instruction which converts the residency code to a boolean value.
15.3.8. Chroma Reconstruction
In some color models, the color representation is defined in terms of monochromatic light intensity (often called “luma”) and color differences relative to this intensity, often called “chroma”. It is common for color models other than RGB to represent the chroma channels at lower spatial resolution than the luma channel. This approach is used to take advantage of the eye’s lower spatial sensitivity to color compared with its sensitivity to brightness. Less commonly, the same approach is used with additive color, since the green channel dominates the eye’s sensitivity to light intensity and the spatial sensitivity to color introduced by red and blue is lower.
Lower-resolution channels are “downsampled” by resizing them to a lower spatial resolution than the channel representing luminance. The process of reconstructing a full color value for texture access involves accessing both chroma and luma values at the same location. To generate the color accurately, the values of the lower-resolution channels at the location of the luma samples must be reconstructed from the lower-resolution sample locations, an operation known here as “chroma reconstruction” irrespective of the actual color model.
The location of the chroma samples relative to the luma coordinates is
determined by the xChromaOffset and yChromaOffset members of the
VkSamplerYcbcrConversionCreateInfo structure used to create the
sampler Y’CBCR conversion.
The following diagrams show the relationship between unnormalized (u,v) coordinates and (i,j) integer texel positions in the luma channel (shown in black, with circles showing integer sample positions) and the texel coordinates of reduced-resolution chroma channels, shown as crosses in red.
|
Note
If the chroma values are reconstructed at the locations of the luma samples
by means of interpolation, chroma samples from outside the image bounds are
needed; these are determined according to Wrapping Operation.
These diagrams represent this by showing the bounds of the “chroma texel”
extending beyond the image bounds, and including additional chroma sample
positions where required for interpolation.
The limits of a sample for |
Reconstruction is implemented in one of two ways:
If the format of the image that is to be sampled sets
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT,
or the VkSamplerYcbcrConversionCreateInfo’s
forceExplicitReconstruction is set to VK_TRUE, reconstruction is
performed as an explicit step independent of filtering, described in the
Explicit Reconstruction section.
If the format of the image that is to be sampled does not set
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT
and if the VkSamplerYcbcrConversionCreateInfo’s
forceExplicitReconstruction is set to VK_FALSE, reconstruction
is performed as an implicit part of filtering prior to color model
conversion, with no separate post-conversion texel filtering step, as
described in the Implicit Reconstruction
section.
Explicit Reconstruction
-
If the
chromaFiltermember of the VkSamplerYcbcrConversionCreateInfo structure isVK_FILTER_NEAREST:-
If the format’s R and B channels are reduced in resolution in just width by a factor of two relative to the G channel (i.e. this is a “
_422” format), the \(\tau_{ijk}[level]\) values accessed by texel filtering are reconstructed as follows:\[\begin{aligned} \tau_R'(i, j) & = \tau_R(\lfloor{i\times 0.5}\rfloor, j)[level] \\ \tau_B'(i, j) & = \tau_B(\lfloor{i\times 0.5}\rfloor, j)[level] \end{aligned}\] -
If the format’s R and B channels are reduced in resolution in width and height by a factor of two relative to the G channel (i.e. this is a “
_420” format), the \(\tau_{ijk}[level]\) values accessed by texel filtering are reconstructed as follows:\[\begin{aligned} \tau_R'(i, j) & = \tau_R(\lfloor{i\times 0.5}\rfloor, \lfloor{j\times 0.5}\rfloor)[level] \\ \tau_B'(i, j) & = \tau_B(\lfloor{i\times 0.5}\rfloor, \lfloor{j\times 0.5}\rfloor)[level] \end{aligned}\]NotexChromaOffsetandyChromaOffsethave no effect ifchromaFilterisVK_FILTER_NEARESTfor explicit reconstruction.
-
-
If the
chromaFiltermember of the VkSamplerYcbcrConversionCreateInfo structure isVK_FILTER_LINEAR:-
If the format’s R and B channels are reduced in resolution in just width by a factor of two relative to the G channel (i.e. this is a “422” format):
-
If
xChromaOffsetisVK_CHROMA_LOCATION_COSITED_EVEN:\[\tau_{RB}'(i,j) = \begin{cases} \tau_{RB}(\lfloor{i\times 0.5}\rfloor,j)[level], & 0.5 \times i = \lfloor{0.5 \times i}\rfloor\\ 0.5\times\tau_{RB}(\lfloor{i\times 0.5}\rfloor,j)[level] + \\ 0.5\times\tau_{RB}(\lfloor{i\times 0.5}\rfloor + 1,j)[level], & 0.5 \times i \neq \lfloor{0.5 \times i}\rfloor \end{cases}\] -
If
xChromaOffsetisVK_CHROMA_LOCATION_MIDPOINT:\[\tau_{RB}(i,j)' = \begin{cases} 0.25 \times \tau_{RB}(\lfloor{i\times 0.5}\rfloor - 1,j)[level] + \\ 0.75 \times \tau_{RB}(\lfloor{i\times 0.5}\rfloor,j)[level], & 0.5 \times i = \lfloor{0.5 \times i}\rfloor\\ 0.75 \times \tau_{RB}(\lfloor{i\times 0.5}\rfloor,j)[level] + \\ 0.25 \times \tau_{RB}(\lfloor{i\times 0.5}\rfloor + 1,j)[level], & 0.5 \times i \neq \lfloor{0.5 \times i}\rfloor \end{cases}\]
-
-
If the format’s R and B channels are reduced in resolution in width and height by a factor of two relative to the G channel (i.e. this is a “420” format), a similar relationship applies. Due to the number of options, these formulae are expressed more concisely as follows:
xChromaOffsetδi COSITED_EVEN0
MIDPOINT0.5
yChromaOffsetδj COSITED_EVEN0
MIDPOINT0.5
\[\begin{aligned} \tau_{RB}'(i,j) = &\\ &\tau_{RB}(\lfloor 0.5\times(i-\delta_i)\rfloor, \lfloor 0.5\times(j-\delta_j)\rfloor)[level] && \times (1 - (0.5\times(i-\delta_i) - \lfloor 0.5\times(i-\delta_i)\rfloor)) && \times (1 - (0.5\times(j-\delta_j) - \lfloor 0.5\times(j-\delta_j)\rfloor)) +\\ &\tau_{RB}(1+\lfloor 0.5\times(i-\delta_i)\rfloor, \lfloor 0.5\times(j-\delta_j)\rfloor)[level] && \times (0.5\times(i-\delta_i) - \lfloor 0.5\times(i-\delta_i)\rfloor) && \times (1 - (0.5\times(j-\delta_j) - \lfloor 0.5\times(j-\delta_j)\rfloor)) +\\ &\tau_{RB}(\lfloor 0.5\times(i-\delta_i)\rfloor, 1+\lfloor 0.5\times(j-\delta_j)\rfloor)[level] && \times (1 - (0.5\times(i-\delta_i) - \lfloor 0.5\times(i-\delta_i)\rfloor)) && \times (0.5\times(j-\delta_j) - \lfloor 0.5\times(j-\delta_j)\rfloor) +\\ &\tau_{RB}(1+\lfloor 0.5\times(i-\delta_i)\rfloor, 1+\lfloor 0.5\times(j-\delta_j)\rfloor)[level] && \times (0.5\times(i-\delta_i) - \lfloor 0.5\times(i-\delta_i)\rfloor) && \times (0.5\times(j-\delta_j) - \lfloor 0.5\times(j-\delta_j)\rfloor) \end{aligned}\]
-
|
Note
In the case where the texture itself is bilinearly interpolated as described
in Texel Filtering, thus requiring four
full-color samples for the filtering operation, and where the reconstruction
of these samples uses bilinear interpolation in the chroma channels due to
|
Implicit Reconstruction
Implicit reconstruction takes place by the samples being interpolated, as
required by the filter settings of the sampler, except that
chromaFilter takes precedence for the chroma samples.
If chromaFilter is VK_FILTER_NEAREST, an implementation may
behave as if xChromaOffset and yChromaOffset were both
VK_CHROMA_LOCATION_MIDPOINT, irrespective of the values set.
|
Note
This will not have any visible effect if the locations of the luma samples coincide with the location of the samples used for rasterization. |
The sample coordinates are adjusted by the downsample factor of the channel (such that, for example, the sample coordinates are divided by two if the channel has a downsample factor of two relative to the luma channel):
15.3.9. Sampler Y’CBCR Conversion
Sampler Y’CBCR conversion performs the following operations, which an implementation may combine into a single mathematical operation:
Sampler Y’CBCR Range Expansion
Sampler Y’CBCR range expansion is applied to color channel values after all texel input operations which are not specific to sampler Y’CBCR conversion. For example, the input values to this stage have been converted using the normal format conversion rules.
Sampler Y’CBCR range expansion is not applied if ycbcrModel is
VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY.
That is, the shader receives the vector C'rgba as output by the Component
Swizzle stage without further modification.
For other values of ycbcrModel, range expansion is applied to the
texel channel values output by the Component
Swizzle defined by the components member of
VkSamplerYcbcrConversionCreateInfo.
Range expansion applies independently to each channel of the image.
For the purposes of range expansion and Y’CBCR model conversion, the R
and B channels contain color difference (chroma) values and the G channel
contains luma.
The A channel is not modified by sampler Y’CBCR range expansion.
The range expansion to be applied is defined by the ycbcrRange member
of the VkSamplerYcbcrConversionCreateInfo structure:
-
If
ycbcrRangeisVK_SAMPLER_YCBCR_RANGE_ITU_FULL, the following transformations are applied:\[\begin{aligned} Y' &= C'_{rgba}[G] \\ C_B &= C'_{rgba}[B] - {{2^{(n-1)}}\over{(2^n) - 1}} \\ C_R &= C'_{rgba}[R] - {{2^{(n-1)}}\over{(2^n) - 1}} \end{aligned}\]NoteThese formulae correspond to the “full range” encoding in the Khronos Data Format Specification.
Should any future amendments be made to the ITU specifications from which these equations are derived, the formulae used by Vulkan may also be updated to maintain parity.
-
If
ycbcrRangeisVK_SAMPLER_YCBCR_RANGE_ITU_NARROW, the following transformations are applied:\[\begin{aligned} Y' &= {{C'_{rgba}[G] \times (2^n-1) - 16\times 2^{n-8}}\over{219\times 2^{n-8}}} \\ C_B &= {{C'_{rgba}[B] \times \left(2^n-1\right) - 128\times 2^{n-8}}\over{224\times 2^{n-8}}} \\ C_R &= {{C'_{rgba}[R] \times \left(2^n-1\right) - 128\times 2^{n-8}}\over{224\times 2^{n-8}}} \end{aligned}\]NoteThese formulae correspond to the “narrow range” encoding in the Khronos Data Format Specification.
-
n is the bit-depth of the channels in the format.
The precision of the operations performed during range expansion must be at least that of the source format.
An implementation may clamp the results of these range expansion operations such that Y' falls in the range [0,1], and/or such that CB and CR fall in the range [-0.5,0.5].
Sampler Y’CBCR Model Conversion
The range-expanded values are converted between color models, according to
the color model conversion specified in the ycbcrModel member:
VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY-
The color channels are not modified by the color model conversion since they are assumed already to represent the desired color model in which the shader is operating; Y’CBCR range expansion is also ignored.
VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY-
The color channels are not modified by the color model conversion and are assumed to be treated as though in Y’CBCR form both in memory and in the shader; Y’CBCR range expansion is applied to the channels as for other Y’CBCR models, with the vector (CR,Y',CB,A) provided to the shader.
VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_709-
The color channels are transformed from a Y’CBCR representation to an R’G’B' representation as described in the “BT.709 Y’CBCR conversion” section of the Khronos Data Format Specification.
VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_601-
The color channels are transformed from a Y’CBCR representation to an R’G’B' representation as described in the “BT.601 Y’CBCR conversion” section of the Khronos Data Format Specification.
VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_2020-
The color channels are transformed from a Y’CBCR representation to an R’G’B' representation as described in the “BT.2020 Y’CBCR conversion” section of the Khronos Data Format Specification.
In this operation, each output channel is dependent on each input channel.
An implementation may clamp the R’G’B' results of these conversions to the range [0,1].
The precision of the operations performed during model conversion must be at least that of the source format.
The alpha channel is not modified by these model conversions.
|
Note
Sampling operations in a non-linear color space can introduce color and intensity shifts at sharp transition boundaries. To avoid this issue, the technically precise color correction sequence described in the “Introduction to Color Conversions” chapter of the Khronos Data Format Specification may be performed as follows:
The additional calculations and, especially, additional number of sampling
operations in the |
15.4. Texel Output Operations
Texel output instructions are SPIR-V image instructions that write to an image. Texel output operations are a set of steps that are performed on state, coordinates, and texel values while processing a texel output instruction, and which are common to some or all texel output instructions. They include the following steps, which are performed in the listed order:
15.4.1. Texel Output Validation Operations
Texel output validation operations inspect instruction/image state or coordinates, and in certain circumstances cause the write to have no effect. There are a series of validations that the texel undergoes.
Texel Format Validation
If the image format of the OpTypeImage is not compatible with the
VkImageView’s format, the effect of the write on the image
view’s memory is undefined, but the write must not access memory outside of
the image view.
15.4.2. Integer Texel Coordinate Validation
The integer texel coordinates are validated according to the same rules as for texel input coordinate validation.
If the texel fails integer texel coordinate validation, then the write has no effect.
15.4.3. Sparse Texel Operation
If the texel attempts to write to an unbound region of a sparse image, the
texel is a sparse unbound texel.
In such a case, if the
VkPhysicalDeviceSparseProperties::residencyNonResidentStrict
property is VK_TRUE, the sparse unbound texel write has no effect.
If residencyNonResidentStrict is VK_FALSE, the write may have a
side effect that becomes visible to other accesses to unbound texels in any
resource, but will not be visible to any device memory allocated by the
application.
15.4.4. Texel Output Format Conversion
If the image format is sRGB, a linear to sRGB conversion is applied to the R, G, and B components as described in the “sRGB EOTF” section of the Khronos Data Format Specification. The A component, if present, is unchanged.
Texels then undergo a format conversion from the floating point, signed, or unsigned integer type of the texel data to the VkFormat of the image view. Any unused components are ignored.
Each component is converted based on its type and size (as defined in the Format Definition section for each VkFormat), using the appropriate equations in 16-Bit Floating-Point Numbers and Fixed-Point Data Conversion.
15.5. Derivative Operations
SPIR-V derivative instructions include OpDPdx, OpDPdy,
OpDPdxFine, OpDPdyFine, OpDPdxCoarse, and OpDPdyCoarse.
Derivative instructions are only available in a fragment shader.
Derivatives are computed as if there is a 2×2 neighborhood of fragments for each fragment shader invocation. These neighboring fragments are used to compute derivatives with the assumption that the values of P in the neighborhood are piecewise linear. It is further assumed that the values of P in the neighborhood are locally continuous, therefore derivatives in non-uniform control flow are undefined.
The Fine derivative instructions must return the values above, for a
group of fragments in a 2×2 neighborhood.
Coarse derivatives may return only two values.
In this case, the values should be:
OpDPdx and OpDPdy must return the same result as either
OpDPdxFine or OpDPdxCoarse and either OpDPdyFine or
OpDPdyCoarse, respectively.
Implementations must make the same choice of either coarse or fine for both
OpDPdx and OpDPdy, and implementations should make the choice
that is more efficient to compute.
For multi-planar formats, the derivatives are computed based on the plane with the largest dimensions.
15.6. Normalized Texel Coordinate Operations
If the image sampler instruction provides normalized texel coordinates, some of the following operations are performed.
15.6.1. Projection Operation
For Proj image operations, the normalized texel coordinates
(s,t,r,q,a) and (if present) the Dref coordinate are
transformed as follows:
15.6.2. Derivative Image Operations
Derivatives are used for LOD selection.
These derivatives are either implicit (in an ImplicitLod image
instruction in a fragment shader) or explicit (provided explicitly by shader
to the image instruction in any shader).
For implicit derivatives image instructions, the derivatives of texel coordinates are calculated in the same manner as derivative operations above. That is:
Partial derivatives not defined above for certain image dimensionalities are set to zero.
For explicit LOD image instructions, if the optional SPIR-V operand Grad is provided, then the operand values are used for the derivatives. The number of components present in each derivative for a given image dimensionality matches the number of partial derivatives computed above.
If the optional SPIR-V operand Lod is provided, then derivatives are set to zero, the cube map derivative transformation is skipped, and the scale factor operation is skipped. Instead, the floating point scalar coordinate is directly assigned to λbase as described in Level-of-Detail Operation.
For implicit derivative image instructions, the partial derivative values may be computed by linear approximation using a 2×2 neighborhood of shader invocations (known as a quad), as described above. If the instruction is in control flow that is not uniform across the quad, then the derivative values and hence the implicit LOD values are undefined.
If the image or sampler object used by an implicit derivative image
instruction is not uniform across the quad and
quadDivergentImplicitLod
is not supported, then the derivative and LOD values are undefined.
Implicit derivatives are well-defined when the image and sampler and control
flow are uniform across the quad, even if they diverge between different
quads.
If
quadDivergentImplicitLod
is supported, then derivatives and implicit LOD values are well-defined even
if the image or sampler object are not uniform within a quad.
The derivatives are computed as specified above, and the implicit LOD
calculation proceeds for each shader invocation using its respective image
and sampler object.
For the purposes of implicit derivatives, Flat fragment input variables
are uniform within a quad.
15.6.3. Cube Map Face Selection and Transformations
For cube map image instructions, the (s,t,r) coordinates are treated as a direction vector (rx,ry,rz). The direction vector is used to select a cube map face. The direction vector is transformed to a per-face texel coordinate system (sface,tface), The direction vector is also used to transform the derivatives to per-face derivatives.
15.6.4. Cube Map Face Selection
The direction vector selects one of the cube map’s faces based on the largest magnitude coordinate direction (the major axis direction). Since two or more coordinates can have identical magnitude, the implementation must have rules to disambiguate this situation.
The rules should have as the first rule that rz wins over ry and rx, and the second rule that ry wins over rx. An implementation may choose other rules, but the rules must be deterministic and depend only on (rx,ry,rz).
The layer number (corresponding to a cube map face), the coordinate selections for sc, tc, rc, and the selection of derivatives, are determined by the major axis direction as specified in the following two tables.
| Major Axis Direction | Layer Number | Cube Map Face | sc | tc | rc |
|---|---|---|---|---|---|
+rx |
0 |
Positive X |
-rz |
-ry |
rx |
-rx |
1 |
Negative X |
+rz |
-ry |
rx |
+ry |
2 |
Positive Y |
+rx |
+rz |
ry |
-ry |
3 |
Negative Y |
+rx |
-rz |
ry |
+rz |
4 |
Positive Z |
+rx |
-ry |
rz |
-rz |
5 |
Negative Z |
-rx |
-ry |
rz |
| Major Axis Direction | ∂sc / ∂x | ∂sc / ∂y | ∂tc / ∂x | ∂tc / ∂y | ∂rc / ∂x | ∂rc / ∂y |
|---|---|---|---|---|---|---|
+rx |
-∂rz / ∂x |
-∂rz / ∂y |
-∂ry / ∂x |
-∂ry / ∂y |
+∂rx / ∂x |
+∂rx / ∂y |
-rx |
+∂rz / ∂x |
+∂rz / ∂y |
-∂ry / ∂x |
-∂ry / ∂y |
-∂rx / ∂x |
-∂rx / ∂y |
+ry |
+∂rx / ∂x |
+∂rx / ∂y |
+∂rz / ∂x |
+∂rz / ∂y |
+∂ry / ∂x |
+∂ry / ∂y |
-ry |
+∂rx / ∂x |
+∂rx / ∂y |
-∂rz / ∂x |
-∂rz / ∂y |
-∂ry / ∂x |
-∂ry / ∂y |
+rz |
+∂rx / ∂x |
+∂rx / ∂y |
-∂ry / ∂x |
-∂ry / ∂y |
+∂rz / ∂x |
+∂rz / ∂y |
-rz |
-∂rx / ∂x |
-∂rx / ∂y |
-∂ry / ∂x |
-∂ry / ∂y |
-∂rz / ∂x |
-∂rz / ∂y |
15.6.5. Cube Map Coordinate Transformation
15.6.6. Cube Map Derivative Transformation
|
editing-note
(Bill) Note that we never revisited ARB_texture_cubemap after we introduced dependent texture fetches (ARB_fragment_program and ARB_fragment_shader). The derivatives of sface and tface are only valid for non-dependent texture fetches (pre OpenGL 2.0). |
15.6.7. Scale Factor Operation, Level-of-Detail Operation and Image Level(s) Selection
LOD selection can be either explicit (provided explicitly by the image
instruction) or implicit (determined from a scale factor calculated from the
derivatives).
The implicit LOD selected can be queried using the SPIR-V instruction
OpImageQueryLod, which gives access to the λ' and
dl values, defined below.
Scale Factor Operation
The magnitude of the derivatives are calculated by:
-
mux = |∂s/∂x| × wbase
-
mvx = |∂t/∂x| × hbase
-
mwx = |∂r/∂x| × dbase
-
muy = |∂s/∂y| × wbase
-
mvy = |∂t/∂y| × hbase
-
mwy = |∂r/∂y| × dbase
where:
-
∂t/∂x = ∂t/∂y = 0 (for 1D images)
-
∂r/∂x = ∂r/∂y = 0 (for 1D, 2D or Cube images)
and
-
wbase = image.w
-
hbase = image.h
-
dbase = image.d
(for the baseMipLevel, from the image descriptor).
A point sampled in screen space has an elliptical footprint in texture space. The minimum and maximum scale factors (ρmin, ρmax) should be the minor and major axes of this ellipse.
The scale factors ρx and ρy, calculated from the magnitude of the derivatives in x and y, are used to compute the minimum and maximum scale factors.
ρx and ρy may be approximated with functions fx and fy, subject to the following constraints:
|
editing-note
(Bill) For reviewers only - anticipating questions. We only support implicit derivatives for normalized texel coordinates. So we are documenting the derivatives in s,t,r (normalized texel coordinates) rather than u,v,w (unnormalized texel coordinates) as in OpenGL and OpenGL ES specifications. (I know, u,v,w is the way it has been documented since OpenGL V1.0.) Also there is no reason to have conditional application of wbase, hbase, dbase for rectangle textures either, since they do not support implicit derivatives. |
The minimum and maximum scale factors (ρmin,ρmax) are determined by:
-
ρmax = max(ρx, ρy)
-
ρmin = min(ρx, ρy)
The ratio of anisotropy is determined by:
-
η = min(ρmax/ρmin, maxAniso)
where:
-
sampler.maxAniso =
maxAnisotropy(from sampler descriptor) -
limits.maxAniso =
maxSamplerAnisotropy(from physical device limits) -
maxAniso = min(sampler.maxAniso, limits.maxAniso)
If ρmax = ρmin = 0, then all the partial derivatives are
zero, the fragment’s footprint in texel space is a point, and N
should be treated as 1.
If ρmax ≠ 0 and ρmin = 0 then all partial
derivatives along one axis are zero, the fragment’s footprint in texel space
is a line segment, and η should be treated as maxAniso.
However, anytime the footprint is small in texel space the implementation
may use a smaller value of η, even when ρmin is zero
or close to zero.
If either VkPhysicalDeviceFeatures::samplerAnisotropy or
VkSamplerCreateInfo::anisotropyEnable are VK_FALSE,
maxAniso is set to 1.
If η = 1, sampling is isotropic. If η > 1, sampling is anisotropic.
The sampling rate (N) is derived as:
-
N = ⌈η⌉
An implementation may round N up to the nearest supported sampling rate. An implementation may use the value of N as an approximation of η.
Level-of-Detail Operation
The LOD parameter λ is computed as follows:
where:
and maxSamplerLodBias is the value of the VkPhysicalDeviceLimits
feature maxSamplerLodBias.
Image Level(s) Selection
The image level(s) d, dhi, and dlo which texels are read from are determined by an image-level parameter dl, which is computed based on the LOD parameter, as follows:
where:
and
-
levelbase =
baseMipLevel -
q =
levelCount- 1
baseMipLevel and levelCount are taken from the
subresourceRange of the image view.
If the sampler’s mipmapMode is VK_SAMPLER_MIPMAP_MODE_NEAREST,
then the level selected is d = dl.
If the sampler’s mipmapMode is VK_SAMPLER_MIPMAP_MODE_LINEAR,
two neighboring levels are selected:
δ is the fractional value used for linear filtering between levels.
15.6.8. (s,t,r,q,a) to (u,v,w,a) Transformation
The normalized texel coordinates are scaled by the image level dimensions and the array layer is selected. This transformation is performed once for each level (d or dhi and dlo) used in filtering.
Operations then proceed to Unnormalized Texel Coordinate Operations.
15.7. Unnormalized Texel Coordinate Operations
15.7.1. (u,v,w,a) to (i,j,k,l,n) Transformation And Array Layer Selection
The unnormalized texel coordinates are transformed to integer texel coordinates relative to the selected mipmap level.
The layer index l is computed as:
-
l = clamp(RNE(a), 0,
layerCount- 1) +baseArrayLayer
where layerCount is the number of layers in the image subresource
range of the image view, baseArrayLayer is the first layer from the
subresource range, and where:
The sample index n is assigned the value zero.
Nearest filtering (VK_FILTER_NEAREST) computes the integer texel
coordinates that the unnormalized coordinates lie within:
Linear filtering (VK_FILTER_LINEAR) computes a set of neighboring
coordinates which bound the unnormalized coordinates.
The integer texel coordinates are combinations of i0 or i1,
j0 or j1, k0 or k1, as well as weights
α, β, and γ.
Cubic filtering (VK_FILTER_CUBIC_IMG) computes a set of neighboring
coordinates which bound the unnormalized coordinates.
The integer texel coordinates are combinations of i0, i1,
i2 or i3, j0, j1, j2 or j3,
as well as weights α and β.
If the image instruction includes a ConstOffset operand, the constant offsets (Δi, Δj, Δk) are added to (i,j,k) components of the integer texel coordinates.
15.8. Integer Texel Coordinate Operations
Integer texel coordinate operations may supply a LOD which texels are to be
read from or written to using the optional SPIR-V operand Lod.
If the Lod is provided then it must be an integer.
The image level selected is:
If d does not lie in the range [baseMipLevel,
baseMipLevel + levelCount) then any values fetched are
undefined, and any writes are discarded.
15.9. Image Sample Operations
15.9.1. Wrapping Operation
Cube images ignore the wrap modes specified in the sampler.
Instead, if VK_FILTER_NEAREST is used within a mip level then
VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE is used, and if
VK_FILTER_LINEAR is used within a mip level then sampling at the edges
is performed as described earlier in the Cube map
edge handling section.
The first integer texel coordinate i is transformed based on the
addressModeU parameter of the sampler.
where:
j (for 2D and Cube image) and k (for 3D image) are similarly
transformed based on the addressModeV and addressModeW
parameters of the sampler, respectively.
15.9.2. Texel Gathering
SPIR-V instructions with Gather in the name return a vector derived
from a 2×2 rectangular region of texels in the base level of the image
view.
The rules for the VK_FILTER_LINEAR minification filter are applied to
identify the four selected texels.
Each texel is then converted to an RGBA value according to
conversion to RGBA and then
swizzled.
A four-component vector is then assembled by taking the component indicated
by the Component value in the instruction from the swizzled color value
of the four texels:
where:
OpImage*Gather must not be used on a sampled image with
sampler Y’CBCR conversion enabled.
15.9.3. Texel Filtering
If λ is less than or equal to zero, the texture is said to be
magnified, and the filter mode within a mip level is selected by the
magFilter in the sampler.
If λ is greater than zero, the texture is said to be
minified, and the filter mode within a mip level is selected by the
minFilter in the sampler.
Within a mip level, VK_FILTER_NEAREST filtering selects a single value
using the (i, j, k) texel coordinates, with all texels taken from
layer l.
Within a mip level, VK_FILTER_LINEAR filtering combines 8 (for 3D), 4
(for 2D or Cube), or 2 (for 1D) texel values, using the weights computed
earlier:
The function reduce() is defined to operate on pairs of weights and
texel values as follows.
When using linear or anisotropic filtering, the values of multiple texels
are combined using a weighted average to produce a filtered texture value.
However, a filtered texture value can also be produced by computing
per-component minimum and maximum values over the set of texels that would
normally be averaged.
The VkSamplerReductionModeCreateInfoEXT::reductionMode controls
the process by which multiple texels are combined to produce a filtered
texture value.
When set to VK_SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE_EXT, a weighted
average is computed.
If the reduction mode is VK_SAMPLER_REDUCTION_MODE_MIN_EXT or
VK_SAMPLER_REDUCTION_MODE_MAX_EXT, reduce() computes a
component-wise minimum or maximum, respectively, of the components of the
set of provided texels with non-zero weights.
Within a mip level, VK_FILTER_CUBIC_IMG filtering computes a weighted
average of 16 (for 2D), or 4 (for 1D) texel values, using the weights
computed during texel selection.
Catmull-Rom Spine interpolation of four points is defined by the equation:
Using the values calculated in texel selection, this equation is applied to the four points in 1D images. For 2D images, the this equation is evaluated first for each row, and the result is then fed back into the equation and interpolated again:
-
τ1D[level] = cinterp(τi0[level], τi1[level], τi2[level], τi3[level], α)
-
τj0[level] = cinterp(τi0j0[level], τi1j0[level], τi2j0[level], τi3j0[level], α)
-
τj1[level] = cinterp(τi0j1[level], τi1j1[level], τi2j1[level], τi3j1[level], α)
-
τj2[level] = cinterp(τi0j2[level], τi1j2[level], τi2j2[level], τi3j2[level], α)
-
τj3[level] = cinterp(τi0j3[level], τi1j3[level], τi2j3[level], τi3j3[level], α)
-
τ2D[level] = cinterp(τj0[level], τj1[level], τj2[level], τj3[level], β)
Finally, mipmap filtering either selects a value from one mip level or computes a weighted average between neighboring mip levels:
15.9.4. Texel Anisotropic Filtering
Anisotropic filtering is enabled by the anisotropyEnable in the
sampler.
When enabled, the image filtering scheme accounts for a degree of
anisotropy.
The particular scheme for anisotropic texture filtering is implementation
dependent.
Implementations should consider the magFilter, minFilter and
mipmapMode of the sampler to control the specifics of the anisotropic
filtering scheme used.
In addition, implementations should consider minLod and maxLod
of the sampler.
The following describes one particular approach to implementing anisotropic filtering for the 2D Image case, implementations may choose other methods:
Given a magFilter, minFilter of VK_FILTER_LINEAR and a
mipmapMode of VK_SAMPLER_MIPMAP_MODE_NEAREST:
Instead of a single isotropic sample, N isotropic samples are be sampled within the image footprint of the image level d to approximate an anisotropic filter. The sum τ2Daniso is defined using the single isotropic τ2D(u,v) at level d.
When VkSamplerReductionModeCreateInfoEXT::reductionMode is set
to VK_SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE_EXT, the above summation
is used.
If the reduction mode is VK_SAMPLER_REDUCTION_MODE_MIN_EXT or
VK_SAMPLER_REDUCTION_MODE_MAX_EXT, then the value is instead computed
as \tau_{2Daniso} = reduce(\tau_1, …, \tau_N), combining all texel
values with non-zero weights.
15.10. Image Operation Steps
Each step described in this chapter is performed by a subset of the image instructions:
-
Texel Input Validation Operations, Format Conversion, Texel Replacement, Conversion to RGBA, and Component Swizzle: Performed by all instructions except
OpImageWrite. -
Depth Comparison: Performed by
OpImage*Drefinstructions. -
All Texel output operations: Performed by
OpImageWrite. -
Projection: Performed by all
OpImage*Projinstructions. -
Derivative Image Operations, Cube Map Operations, Scale Factor Operation, Level-of-Detail Operation and Image Level(s) Selection, and Texel Anisotropic Filtering: Performed by all
OpImageSample* andOpImageSparseSample* instructions. -
(s,t,r,q,a) to (u,v,w,a) Transformation, Wrapping, and (u,v,w,a) to (i,j,k,l,n) Transformation And Array Layer Selection: Performed by all
OpImageSample,OpImageSparseSample, andOpImage*Gatherinstructions. -
Texel Gathering: Performed by
OpImage*Gatherinstructions. -
Texel Filtering: Performed by all
OpImageSample* andOpImageSparseSample* instructions. -
Sparse Residency: Performed by all
OpImageSparse* instructions.
16. Queries
Queries provide a mechanism to return information about the processing of a sequence of Vulkan commands. Query operations are asynchronous, and as such, their results are not returned immediately. Instead, their results, and their availability status, are stored in a Query Pool. The state of these queries can be read back on the host, or copied to a buffer object on the device.
The supported query types are Occlusion Queries, Pipeline Statistics Queries, and Timestamp Queries.
16.1. Query Pools
Queries are managed using query pool objects. Each query pool is a collection of a specific number of queries of a particular type.
Query pools are represented by VkQueryPool handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkQueryPool)
To create a query pool, call:
VkResult vkCreateQueryPool(
VkDevice device,
const VkQueryPoolCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkQueryPool* pQueryPool);
-
deviceis the logical device that creates the query pool. -
pCreateInfois a pointer to an instance of theVkQueryPoolCreateInfostructure containing the number and type of queries to be managed by the pool. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pQueryPoolis a pointer to aVkQueryPoolhandle in which the resulting query pool object is returned.
The VkQueryPoolCreateInfo structure is defined as:
typedef struct VkQueryPoolCreateInfo {
VkStructureType sType;
const void* pNext;
VkQueryPoolCreateFlags flags;
VkQueryType queryType;
uint32_t queryCount;
VkQueryPipelineStatisticFlags pipelineStatistics;
} VkQueryPoolCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
queryTypeis a VkQueryType value specifying the type of queries managed by the pool. -
queryCountis the number of queries managed by the pool. -
pipelineStatisticsis a bitmask of VkQueryPipelineStatisticFlagBits specifying which counters will be returned in queries on the new pool, as described below in Pipeline Statistics Queries.
pipelineStatistics is ignored if queryType is not
VK_QUERY_TYPE_PIPELINE_STATISTICS.
typedef VkFlags VkQueryPoolCreateFlags;
VkQueryPoolCreateFlags is a bitmask type for setting a mask, but is
currently reserved for future use.
To destroy a query pool, call:
void vkDestroyQueryPool(
VkDevice device,
VkQueryPool queryPool,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the query pool. -
queryPoolis the query pool to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
Possible values of VkQueryPoolCreateInfo::queryType, specifying
the type of queries managed by the pool, are:
typedef enum VkQueryType {
VK_QUERY_TYPE_OCCLUSION = 0,
VK_QUERY_TYPE_PIPELINE_STATISTICS = 1,
VK_QUERY_TYPE_TIMESTAMP = 2,
} VkQueryType;
-
VK_QUERY_TYPE_OCCLUSIONspecifies an occlusion query. -
VK_QUERY_TYPE_PIPELINE_STATISTICSspecifies a pipeline statistics query. -
VK_QUERY_TYPE_TIMESTAMPspecifies a timestamp query.
16.2. Query Operation
The operation of queries is controlled by the commands vkCmdBeginQuery, vkCmdEndQuery, vkCmdResetQueryPool, vkCmdCopyQueryPoolResults, and vkCmdWriteTimestamp.
In order for a VkCommandBuffer to record query management commands,
the queue family for which its VkCommandPool was created must support
the appropriate type of operations (graphics, compute) suitable for the
query type of a given query pool.
Each query in a query pool has a status that is either unavailable or available, and also has state to store the numerical results of a query operation of the type requested when the query pool was created. Resetting a query via vkCmdResetQueryPool sets the status to unavailable and makes the numerical results undefined. Performing a query operation with vkCmdBeginQuery and vkCmdEndQuery changes the status to available when the query finishes, and updates the numerical results. Both the availability status and numerical results are retrieved by calling either vkGetQueryPoolResults or vkCmdCopyQueryPoolResults.
Query commands, for the same query and submitted to the same queue, execute
in their entirety in submission order,
relative to each other.
In effect there is an implicit execution dependency from each such query
command to all query command previously submitted to the same queue.
There is one significant exception to this; if the flags parameter of
vkCmdCopyQueryPoolResults does not include
VK_QUERY_RESULT_WAIT_BIT, execution of vkCmdCopyQueryPoolResults
may happen-before the results of vkCmdEndQuery are available.
After query pool creation, each query is in an undefined state and must be reset prior to use. Queries must also be reset between uses. Using a query that has not been reset will result in undefined behavior.
If a logical device includes multiple physical devices, then each command that writes a query must execute on a single physical device, and any call to vkCmdBeginQuery must execute the corresponding vkCmdEndQuery command on the same physical device.
To reset a range of queries in a query pool, call:
void vkCmdResetQueryPool(
VkCommandBuffer commandBuffer,
VkQueryPool queryPool,
uint32_t firstQuery,
uint32_t queryCount);
-
commandBufferis the command buffer into which this command will be recorded. -
queryPoolis the handle of the query pool managing the queries being reset. -
firstQueryis the initial query index to reset. -
queryCountis the number of queries to reset.
When executed on a queue, this command sets the status of query indices
[firstQuery, firstQuery + queryCount - 1] to
unavailable.
Once queries are reset and ready for use, query commands can be issued to a command buffer. Occlusion queries and pipeline statistics queries count events - drawn samples and pipeline stage invocations, respectively - resulting from commands that are recorded between a vkCmdBeginQuery command and a vkCmdEndQuery command within a specified command buffer, effectively scoping a set of drawing and/or compute commands. Timestamp queries write timestamps to a query pool.
A query must begin and end in the same command buffer, although if it is a
primary command buffer, and the
inherited queries feature is enabled,
it can execute secondary command buffers during the query operation.
For a secondary command buffer to be executed while a query is active, it
must set the occlusionQueryEnable, queryFlags, and/or
pipelineStatistics members of VkCommandBufferInheritanceInfo to
conservative values, as described in the Command
Buffer Recording section.
A query must either begin and end inside the same subpass of a render pass
instance, or must both begin and end outside of a render pass instance
(i.e. contain entire render pass instances).
If queries are used while executing a render pass instance that has
multiview enabled, the query uses N consecutive query indices in the
query pool (starting at query) where N is the number of bits set
in the view mask in the subpass the query is used in.
How the numerical results of the query are distributed among the queries is
implementation-dependent.
For example, some implementations may write each view’s results to a
distinct query, while other implementations may write the total result to
the first query and write zero to the other queries.
However, the sum of the results in all the queries must accurately reflect
the total result of the query summed over all views.
Applications can sum the results from all the queries to compute the total
result.
Queries used with multiview rendering must not span subpasses, i.e. they must begin and end in the same subpass.
To begin a query, call:
void vkCmdBeginQuery(
VkCommandBuffer commandBuffer,
VkQueryPool queryPool,
uint32_t query,
VkQueryControlFlags flags);
-
commandBufferis the command buffer into which this command will be recorded. -
queryPoolis the query pool that will manage the results of the query. -
queryis the query index within the query pool that will contain the results. -
flagsis a bitmask of VkQueryControlFlagBits specifying constraints on the types of queries that can be performed.
If the queryType of the pool is VK_QUERY_TYPE_OCCLUSION and
flags contains VK_QUERY_CONTROL_PRECISE_BIT, an implementation
must return a result that matches the actual number of samples passed.
This is described in more detail in Occlusion Queries.
After beginning a query, that query is considered active within the command buffer it was called in until that same query is ended. Queries active in a primary command buffer when secondary command buffers are executed are considered active for those secondary command buffers.
Bits which can be set in vkCmdBeginQuery::flags, specifying
constraints on the types of queries that can be performed, are:
typedef enum VkQueryControlFlagBits {
VK_QUERY_CONTROL_PRECISE_BIT = 0x00000001,
} VkQueryControlFlagBits;
-
VK_QUERY_CONTROL_PRECISE_BITspecifies the precision of occlusion queries.
typedef VkFlags VkQueryControlFlags;
VkQueryControlFlags is a bitmask type for setting a mask of zero or
more VkQueryControlFlagBits.
To end a query after the set of desired draw or dispatch commands is executed, call:
void vkCmdEndQuery(
VkCommandBuffer commandBuffer,
VkQueryPool queryPool,
uint32_t query);
-
commandBufferis the command buffer into which this command will be recorded. -
queryPoolis the query pool that is managing the results of the query. -
queryis the query index within the query pool where the result is stored.
As queries operate asynchronously, ending a query does not immediately set the query’s status to available. A query is considered finished when the final results of the query are ready to be retrieved by vkGetQueryPoolResults and vkCmdCopyQueryPoolResults, and this is when the query’s status is set to available.
Once a query is ended the query must finish in finite time, unless the state of the query is changed using other commands, e.g. by issuing a reset of the query.
An application can retrieve results either by requesting they be written
into application-provided memory, or by requesting they be copied into a
VkBuffer.
In either case, the layout in memory is defined as follows:
-
The first query’s result is written starting at the first byte requested by the command, and each subsequent query’s result begins
stridebytes later. -
Each query’s result is a tightly packed array of unsigned integers, either 32- or 64-bits as requested by the command, storing the numerical results and, if requested, the availability status.
-
If
VK_QUERY_RESULT_WITH_AVAILABILITY_BITis used, the final element of each query’s result is an integer indicating whether the query’s result is available, with any non-zero value indicating that it is available. -
Occlusion queries write one integer value - the number of samples passed. Pipeline statistics queries write one integer value for each bit that is enabled in the
pipelineStatisticswhen the pool is created, and the statistics values are written in bit order starting from the least significant bit. Timestamps write one integer value. -
If more than one query is retrieved and
strideis not at least as large as the size of the array of integers corresponding to a single query, the values written to memory are undefined.
To retrieve status and results for a set of queries, call:
VkResult vkGetQueryPoolResults(
VkDevice device,
VkQueryPool queryPool,
uint32_t firstQuery,
uint32_t queryCount,
size_t dataSize,
void* pData,
VkDeviceSize stride,
VkQueryResultFlags flags);
-
deviceis the logical device that owns the query pool. -
queryPoolis the query pool managing the queries containing the desired results. -
firstQueryis the initial query index. -
queryCountis the number of queries.firstQueryandqueryCounttogether define a range of queries. For pipeline statistics queries, each query index in the pool contains one integer value for each bit that is enabled in VkQueryPoolCreateInfo::pipelineStatisticswhen the pool is created. -
dataSizeis the size in bytes of the buffer pointed to bypData. -
pDatais a pointer to a user-allocated buffer where the results will be written -
strideis the stride in bytes between results for individual queries withinpData. -
flagsis a bitmask of VkQueryResultFlagBits specifying how and when results are returned.
If no bits are set in flags, and all requested queries are in the
available state, results are written as an array of 32-bit unsigned integer
values.
The behavior when not all queries are available, is described
below.
If VK_QUERY_RESULT_64_BIT is not set and the result overflows a 32-bit
value, the value may either wrap or saturate.
Similarly, if VK_QUERY_RESULT_64_BIT is set and the result overflows a
64-bit value, the value may either wrap or saturate.
If VK_QUERY_RESULT_WAIT_BIT is set, Vulkan will wait for each query to
be in the available state before retrieving the numerical results for that
query.
In this case, vkGetQueryPoolResults is guaranteed to succeed and
return VK_SUCCESS if the queries become available in a finite time
(i.e. if they have been issued and not reset).
If queries will never finish (e.g. due to being reset but not issued), then
vkGetQueryPoolResults may not return in finite time.
If VK_QUERY_RESULT_WAIT_BIT and VK_QUERY_RESULT_PARTIAL_BIT are
both not set then no result values are written to pData for queries
that are in the unavailable state at the time of the call, and
vkGetQueryPoolResults returns VK_NOT_READY.
However, availability state is still written to pData for those
queries if VK_QUERY_RESULT_WITH_AVAILABILITY_BIT is set.
|
Note
Applications must take care to ensure that use of the
For example, if a query has been used previously and a command buffer
records the commands The above also applies when |
|
Note
Applications can double-buffer query pool usage, with a pool per frame, and reset queries at the end of the frame in which they are read. |
If VK_QUERY_RESULT_PARTIAL_BIT is set, VK_QUERY_RESULT_WAIT_BIT
is not set, and the query’s status is unavailable, an intermediate result
value between zero and the final result value is written to pData for
that query.
VK_QUERY_RESULT_PARTIAL_BIT must not be used if the pool’s
queryType is VK_QUERY_TYPE_TIMESTAMP.
If VK_QUERY_RESULT_WITH_AVAILABILITY_BIT is set, the final integer
value written for each query is non-zero if the query’s status was available
or zero if the status was unavailable.
When VK_QUERY_RESULT_WITH_AVAILABILITY_BIT is used, implementations
must guarantee that if they return a non-zero availability value then the
numerical results must be valid, assuming the results are not reset by a
subsequent command.
|
Note
Satisfying this guarantee may require careful ordering by the application, e.g. to read the availability status before reading the results. |
Bits which can be set in vkGetQueryPoolResults::flags and
vkCmdCopyQueryPoolResults::flags, specifying how and when
results are returned, are:
typedef enum VkQueryResultFlagBits {
VK_QUERY_RESULT_64_BIT = 0x00000001,
VK_QUERY_RESULT_WAIT_BIT = 0x00000002,
VK_QUERY_RESULT_WITH_AVAILABILITY_BIT = 0x00000004,
VK_QUERY_RESULT_PARTIAL_BIT = 0x00000008,
} VkQueryResultFlagBits;
-
VK_QUERY_RESULT_64_BITspecifies the results will be written as an array of 64-bit unsigned integer values. If this bit is not set, the results will be written as an array of 32-bit unsigned integer values. -
VK_QUERY_RESULT_WAIT_BITspecifies that Vulkan will wait for each query’s status to become available before retrieving its results. -
VK_QUERY_RESULT_WITH_AVAILABILITY_BITspecifies that the availability status accompanies the results. -
VK_QUERY_RESULT_PARTIAL_BITspecifies that returning partial results is acceptable.
typedef VkFlags VkQueryResultFlags;
VkQueryResultFlags is a bitmask type for setting a mask of zero or
more VkQueryResultFlagBits.
To copy query statuses and numerical results directly to buffer memory, call:
void vkCmdCopyQueryPoolResults(
VkCommandBuffer commandBuffer,
VkQueryPool queryPool,
uint32_t firstQuery,
uint32_t queryCount,
VkBuffer dstBuffer,
VkDeviceSize dstOffset,
VkDeviceSize stride,
VkQueryResultFlags flags);
-
commandBufferis the command buffer into which this command will be recorded. -
queryPoolis the query pool managing the queries containing the desired results. -
firstQueryis the initial query index. -
queryCountis the number of queries.firstQueryandqueryCounttogether define a range of queries. -
dstBufferis aVkBufferobject that will receive the results of the copy command. -
dstOffsetis an offset intodstBuffer. -
strideis the stride in bytes between results for individual queries withindstBuffer. The required size of the backing memory fordstBufferis determined as described above for vkGetQueryPoolResults. -
flagsis a bitmask of VkQueryResultFlagBits specifying how and when results are returned.
vkCmdCopyQueryPoolResults is guaranteed to see the effect of previous
uses of vkCmdResetQueryPool in the same queue, without any additional
synchronization.
Thus, the results will always reflect the most recent use of the query.
flags has the same possible values described above for the flags
parameter of vkGetQueryPoolResults, but the different style of
execution causes some subtle behavioral differences.
Because vkCmdCopyQueryPoolResults executes in order with respect to
other query commands, there is less ambiguity about which use of a query is
being requested.
If no bits are set in flags, results for all requested queries in the
available state are written as 32-bit unsigned integer values, and nothing
is written for queries in the unavailable state.
If VK_QUERY_RESULT_64_BIT is set, the results are written as an array
of 64-bit unsigned integer values as described for
vkGetQueryPoolResults.
If VK_QUERY_RESULT_WAIT_BIT is set, the implementation will wait for
each query’s status to be in the available state before retrieving the
numerical results for that query.
This is guaranteed to reflect the most recent use of the query on the same
queue, assuming that the query is not being simultaneously used by other
queues.
If the query does not become available in a finite amount of time (e.g. due
to not issuing a query since the last reset), a VK_ERROR_DEVICE_LOST
error may occur.
Similarly, if VK_QUERY_RESULT_WITH_AVAILABILITY_BIT is set and
VK_QUERY_RESULT_WAIT_BIT is not set, the availability is guaranteed to
reflect the most recent use of the query on the same queue, assuming that
the query is not being simultaneously used by other queues.
As with vkGetQueryPoolResults, implementations must guarantee that if
they return a non-zero availability value, then the numerical results are
valid.
If VK_QUERY_RESULT_PARTIAL_BIT is set, VK_QUERY_RESULT_WAIT_BIT
is not set, and the query’s status is unavailable, an intermediate result
value between zero and the final result value is written for that query.
VK_QUERY_RESULT_PARTIAL_BIT must not be used if the pool’s
queryType is VK_QUERY_TYPE_TIMESTAMP.
vkCmdCopyQueryPoolResults is considered to be a transfer operation,
and its writes to buffer memory must be synchronized using
VK_PIPELINE_STAGE_TRANSFER_BIT and VK_ACCESS_TRANSFER_WRITE_BIT
before using the results.
Rendering operations such as clears, MSAA resolves, attachment load/store operations, and blits may count towards the results of queries. This behavior is implementation-dependent and may vary depending on the path used within an implementation. For example, some implementations have several types of clears, some of which may include vertices and some not.
16.3. Occlusion Queries
Occlusion queries track the number of samples that pass the per-fragment
tests for a set of drawing commands.
As such, occlusion queries are only available on queue families supporting
graphics operations.
The application can then use these results to inform future rendering
decisions.
An occlusion query is begun and ended by calling vkCmdBeginQuery and
vkCmdEndQuery, respectively.
When an occlusion query begins, the count of passing samples always starts
at zero.
For each drawing command, the count is incremented as described in
Sample Counting.
If flags does not contain VK_QUERY_CONTROL_PRECISE_BIT an
implementation may generate any non-zero result value for the query if the
count of passing samples is non-zero.
|
Note
Not setting |
When an occlusion query finishes, the result for that query is marked as
available.
The application can then either copy the result to a buffer (via
vkCmdCopyQueryPoolResults) or request it be put into host memory (via
vkGetQueryPoolResults).
|
Note
If occluding geometry is not drawn first, samples can pass the depth test, but still not be visible in a final image. |
16.4. Pipeline Statistics Queries
Pipeline statistics queries allow the application to sample a specified set
of VkPipeline counters.
These counters are accumulated by Vulkan for a set of either draw or
dispatch commands while a pipeline statistics query is active.
As such, pipeline statistics queries are available on queue families
supporting either graphics or compute operations.
Further, the availability of pipeline statistics queries is indicated by the
pipelineStatisticsQuery member of the VkPhysicalDeviceFeatures
object (see vkGetPhysicalDeviceFeatures and vkCreateDevice for
detecting and requesting this query type on a VkDevice).
A pipeline statistics query is begun and ended by calling
vkCmdBeginQuery and vkCmdEndQuery, respectively.
When a pipeline statistics query begins, all statistics counters are set to
zero.
While the query is active, the pipeline type determines which set of
statistics are available, but these must be configured on the query pool
when it is created.
If a statistic counter is issued on a command buffer that does not support
the corresponding operation, that counter is undefined after the query has
finished.
At least one statistic counter relevant to the operations supported on the
recording command buffer must be enabled.
Bits which can be set to individually enable pipeline statistics counters
for query pools with VkQueryPoolCreateInfo::pipelineStatistics,
and for secondary command buffers with
VkCommandBufferInheritanceInfo::pipelineStatistics, are:
typedef enum VkQueryPipelineStatisticFlagBits {
VK_QUERY_PIPELINE_STATISTIC_INPUT_ASSEMBLY_VERTICES_BIT = 0x00000001,
VK_QUERY_PIPELINE_STATISTIC_INPUT_ASSEMBLY_PRIMITIVES_BIT = 0x00000002,
VK_QUERY_PIPELINE_STATISTIC_VERTEX_SHADER_INVOCATIONS_BIT = 0x00000004,
VK_QUERY_PIPELINE_STATISTIC_GEOMETRY_SHADER_INVOCATIONS_BIT = 0x00000008,
VK_QUERY_PIPELINE_STATISTIC_GEOMETRY_SHADER_PRIMITIVES_BIT = 0x00000010,
VK_QUERY_PIPELINE_STATISTIC_CLIPPING_INVOCATIONS_BIT = 0x00000020,
VK_QUERY_PIPELINE_STATISTIC_CLIPPING_PRIMITIVES_BIT = 0x00000040,
VK_QUERY_PIPELINE_STATISTIC_FRAGMENT_SHADER_INVOCATIONS_BIT = 0x00000080,
VK_QUERY_PIPELINE_STATISTIC_TESSELLATION_CONTROL_SHADER_PATCHES_BIT = 0x00000100,
VK_QUERY_PIPELINE_STATISTIC_TESSELLATION_EVALUATION_SHADER_INVOCATIONS_BIT = 0x00000200,
VK_QUERY_PIPELINE_STATISTIC_COMPUTE_SHADER_INVOCATIONS_BIT = 0x00000400,
} VkQueryPipelineStatisticFlagBits;
-
VK_QUERY_PIPELINE_STATISTIC_INPUT_ASSEMBLY_VERTICES_BITspecifies that queries managed by the pool will count the number of vertices processed by the input assembly stage. Vertices corresponding to incomplete primitives may contribute to the count. -
VK_QUERY_PIPELINE_STATISTIC_INPUT_ASSEMBLY_PRIMITIVES_BITspecifies that queries managed by the pool will count the number of primitives processed by the input assembly stage. If primitive restart is enabled, restarting the primitive topology has no effect on the count. Incomplete primitives may be counted. -
VK_QUERY_PIPELINE_STATISTIC_VERTEX_SHADER_INVOCATIONS_BITspecifies that queries managed by the pool will count the number of vertex shader invocations. This counter’s value is incremented each time a vertex shader is invoked. -
VK_QUERY_PIPELINE_STATISTIC_GEOMETRY_SHADER_INVOCATIONS_BITspecifies that queries managed by the pool will count the number of geometry shader invocations. This counter’s value is incremented each time a geometry shader is invoked. In the case of instanced geometry shaders, the geometry shader invocations count is incremented for each separate instanced invocation. -
VK_QUERY_PIPELINE_STATISTIC_GEOMETRY_SHADER_PRIMITIVES_BITspecifies that queries managed by the pool will count the number of primitives generated by geometry shader invocations. The counter’s value is incremented each time the geometry shader emits a primitive. Restarting primitive topology using the SPIR-V instructionsOpEndPrimitiveorOpEndStreamPrimitivehas no effect on the geometry shader output primitives count. -
VK_QUERY_PIPELINE_STATISTIC_CLIPPING_INVOCATIONS_BITspecifies that queries managed by the pool will count the number of primitives processed by the Primitive Clipping stage of the pipeline. The counter’s value is incremented each time a primitive reaches the primitive clipping stage. -
VK_QUERY_PIPELINE_STATISTIC_CLIPPING_PRIMITIVES_BITspecifies that queries managed by the pool will count the number of primitives output by the Primitive Clipping stage of the pipeline. The counter’s value is incremented each time a primitive passes the primitive clipping stage. The actual number of primitives output by the primitive clipping stage for a particular input primitive is implementation-dependent but must satisfy the following conditions:-
If at least one vertex of the input primitive lies inside the clipping volume, the counter is incremented by one or more.
-
Otherwise, the counter is incremented by zero or more.
-
-
VK_QUERY_PIPELINE_STATISTIC_FRAGMENT_SHADER_INVOCATIONS_BITspecifies that queries managed by the pool will count the number of fragment shader invocations. The counter’s value is incremented each time the fragment shader is invoked. -
VK_QUERY_PIPELINE_STATISTIC_TESSELLATION_CONTROL_SHADER_PATCHES_BITspecifies that queries managed by the pool will count the number of patches processed by the tessellation control shader. The counter’s value is incremented once for each patch for which a tessellation control shader is invoked. -
VK_QUERY_PIPELINE_STATISTIC_TESSELLATION_EVALUATION_SHADER_INVOCATIONS_BITspecifies that queries managed by the pool will count the number of invocations of the tessellation evaluation shader. The counter’s value is incremented each time the tessellation evaluation shader is invoked. -
VK_QUERY_PIPELINE_STATISTIC_COMPUTE_SHADER_INVOCATIONS_BITspecifies that queries managed by the pool will count the number of compute shader invocations. The counter’s value is incremented every time the compute shader is invoked. Implementations may skip the execution of certain compute shader invocations or execute additional compute shader invocations for implementation-dependent reasons as long as the results of rendering otherwise remain unchanged.
These values are intended to measure relative statistics on one implementation. Various device architectures will count these values differently. Any or all counters may be affected by the issues described in Query Operation.
|
Note
For example, tile-based rendering devices may need to replay the scene multiple times, affecting some of the counts. |
If a pipeline has rasterizerDiscardEnable enabled, implementations
may discard primitives after the final vertex processing stage.
As a result, if rasterizerDiscardEnable is enabled, the clipping input
and output primitives counters may not be incremented.
When a pipeline statistics query finishes, the result for that query is
marked as available.
The application can copy the result to a buffer (via
vkCmdCopyQueryPoolResults), or request it be put into host memory (via
vkGetQueryPoolResults).
typedef VkFlags VkQueryPipelineStatisticFlags;
VkQueryPipelineStatisticFlags is a bitmask type for setting a mask of
zero or more VkQueryPipelineStatisticFlagBits.
16.5. Timestamp Queries
Timestamps provide applications with a mechanism for timing the execution
of commands.
A timestamp is an integer value generated by the VkPhysicalDevice.
Unlike other queries, timestamps do not operate over a range, and so do not
use vkCmdBeginQuery or vkCmdEndQuery.
The mechanism is built around a set of commands that allow the application
to tell the VkPhysicalDevice to write timestamp values to a
query pool and then either read timestamp values on the
host (using vkGetQueryPoolResults) or copy timestamp values to a
VkBuffer (using vkCmdCopyQueryPoolResults).
The application can then compute differences between timestamps to
determine execution time.
The number of valid bits in a timestamp value is determined by the
VkQueueFamilyProperties::timestampValidBits property of the
queue on which the timestamp is written.
Timestamps are supported on any queue which reports a non-zero value for
timestampValidBits via vkGetPhysicalDeviceQueueFamilyProperties.
If the timestampComputeAndGraphics limit is VK_TRUE, timestamps are
supported by every queue family that supports either graphics or compute
operations (see VkQueueFamilyProperties).
The number of nanoseconds it takes for a timestamp value to be incremented
by 1 can be obtained from
VkPhysicalDeviceLimits::timestampPeriod after a call to
vkGetPhysicalDeviceProperties.
To request a timestamp, call:
void vkCmdWriteTimestamp(
VkCommandBuffer commandBuffer,
VkPipelineStageFlagBits pipelineStage,
VkQueryPool queryPool,
uint32_t query);
-
commandBufferis the command buffer into which the command will be recorded. -
pipelineStageis one of the VkPipelineStageFlagBits, specifying a stage of the pipeline. -
queryPoolis the query pool that will manage the timestamp. -
queryis the query within the query pool that will contain the timestamp.
vkCmdWriteTimestamp latches the value of the timer when all previous
commands have completed executing as far as the specified pipeline stage,
and writes the timestamp value to memory.
When the timestamp value is written, the availability status of the query is
set to available.
|
Note
If an implementation is unable to detect completion and latch the timer at any specific stage of the pipeline, it may instead do so at any logically later stage. |
vkCmdCopyQueryPoolResults can then be called to copy the timestamp value from the query pool into buffer memory, with ordering and synchronization behavior equivalent to how other queries operate. Timestamp values can also be retrieved from the query pool using vkGetQueryPoolResults. As with other queries, the query must be reset using vkCmdResetQueryPool before requesting the timestamp value be written to it.
While vkCmdWriteTimestamp can be called inside or outside of a render
pass instance, vkCmdCopyQueryPoolResults must only be called outside
of a render pass instance.
Timestamps may only be meaningfully compared if they are written by commands submitted to the same queue.
|
Note
An example of such a comparison is determining the execution time of a sequence of commands. |
If vkCmdWriteTimestamp is called while executing a render pass
instance that has multiview enabled, the timestamp uses N consecutive
query indices in the query pool (starting at query) where N is
the number of bits set in the view mask of the subpass the command is
executed in.
The resulting query values are determined by an implementation-dependent
choice of one of the following behaviors:
-
The first query is a timestamp value and (if more than one bit is set in the view mask) zero is written to the remaining queries. If two timestamps are written in the same subpass, the sum of the execution time of all views between those commands is the difference between the first query written by each command.
-
All N queries are timestamp values. If two timestamps are written in the same subpass, the sum of the execution time of all views between those commands is the sum of the difference between corresponding queries written by each command. The difference between corresponding queries may be the execution time of a single view.
In either case, the application can sum the differences between all N queries to determine the total execution time.
17. Clear Commands
17.1. Clearing Images Outside A Render Pass Instance
Color and depth/stencil images can be cleared outside a render pass instance using vkCmdClearColorImage or vkCmdClearDepthStencilImage, respectively. These commands are only allowed outside of a render pass instance.
To clear one or more subranges of a color image, call:
void vkCmdClearColorImage(
VkCommandBuffer commandBuffer,
VkImage image,
VkImageLayout imageLayout,
const VkClearColorValue* pColor,
uint32_t rangeCount,
const VkImageSubresourceRange* pRanges);
-
commandBufferis the command buffer into which the command will be recorded. -
imageis the image to be cleared. -
imageLayoutspecifies the current layout of the image subresource ranges to be cleared, and must beVK_IMAGE_LAYOUT_SHARED_PRESENT_KHR,VK_IMAGE_LAYOUT_GENERALorVK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL. -
pColoris a pointer to a VkClearColorValue structure that contains the values the image subresource ranges will be cleared to (see Clear Values below). -
rangeCountis the number of image subresource range structures inpRanges. -
pRangespoints to an array of VkImageSubresourceRange structures that describe a range of mipmap levels, array layers, and aspects to be cleared, as described in Image Views. TheaspectMaskof all image subresource ranges must only includeVK_IMAGE_ASPECT_COLOR_BIT.
Each specified range in pRanges is cleared to the value specified by
pColor.
To clear one or more subranges of a depth/stencil image, call:
void vkCmdClearDepthStencilImage(
VkCommandBuffer commandBuffer,
VkImage image,
VkImageLayout imageLayout,
const VkClearDepthStencilValue* pDepthStencil,
uint32_t rangeCount,
const VkImageSubresourceRange* pRanges);
-
commandBufferis the command buffer into which the command will be recorded. -
imageis the image to be cleared. -
imageLayoutspecifies the current layout of the image subresource ranges to be cleared, and must beVK_IMAGE_LAYOUT_GENERALorVK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL. -
pDepthStencilis a pointer to a VkClearDepthStencilValue structure that contains the values the depth and stencil image subresource ranges will be cleared to (see Clear Values below). -
rangeCountis the number of image subresource range structures inpRanges. -
pRangespoints to an array of VkImageSubresourceRange structures that describe a range of mipmap levels, array layers, and aspects to be cleared, as described in Image Views. TheaspectMaskof each image subresource range inpRangescan includeVK_IMAGE_ASPECT_DEPTH_BITif the image format has a depth component, andVK_IMAGE_ASPECT_STENCIL_BITif the image format has a stencil component.pDepthStencilis a pointer to aVkClearDepthStencilValuestructure that contains the values the image subresource ranges will be cleared to (see Clear Values below).
Clears outside render pass instances are treated as transfer operations for the purposes of memory barriers.
17.2. Clearing Images Inside A Render Pass Instance
To clear one or more regions of color and depth/stencil attachments inside a render pass instance, call:
void vkCmdClearAttachments(
VkCommandBuffer commandBuffer,
uint32_t attachmentCount,
const VkClearAttachment* pAttachments,
uint32_t rectCount,
const VkClearRect* pRects);
-
commandBufferis the command buffer into which the command will be recorded. -
attachmentCountis the number of entries in thepAttachmentsarray. -
pAttachmentsis a pointer to an array of VkClearAttachment structures defining the attachments to clear and the clear values to use. -
rectCountis the number of entries in thepRectsarray. -
pRectspoints to an array of VkClearRect structures defining regions within each selected attachment to clear.
vkCmdClearAttachments can clear multiple regions of each attachment
used in the current subpass of a render pass instance.
This command must be called only inside a render pass instance, and
implicitly selects the images to clear based on the current framebuffer
attachments and the command parameters.
The VkClearRect structure is defined as:
typedef struct VkClearRect {
VkRect2D rect;
uint32_t baseArrayLayer;
uint32_t layerCount;
} VkClearRect;
-
rectis the two-dimensional region to be cleared. -
baseArrayLayeris the first layer to be cleared. -
layerCountis the number of layers to clear.
The layers [baseArrayLayer, baseArrayLayer +
layerCount) counting from the base layer of the attachment image view
are cleared.
The VkClearAttachment structure is defined as:
typedef struct VkClearAttachment {
VkImageAspectFlags aspectMask;
uint32_t colorAttachment;
VkClearValue clearValue;
} VkClearAttachment;
-
aspectMaskis a mask selecting the color, depth and/or stencil aspects of the attachment to be cleared.aspectMaskcan includeVK_IMAGE_ASPECT_COLOR_BITfor color attachments,VK_IMAGE_ASPECT_DEPTH_BITfor depth/stencil attachments with a depth component, andVK_IMAGE_ASPECT_STENCIL_BITfor depth/stencil attachments with a stencil component. If the subpass’s depth/stencil attachment isVK_ATTACHMENT_UNUSED, then the clear has no effect. -
colorAttachmentis only meaningful ifVK_IMAGE_ASPECT_COLOR_BITis set inaspectMask, in which case it is an index to thepColorAttachmentsarray in the VkSubpassDescription structure of the current subpass which selects the color attachment to clear. IfcolorAttachmentisVK_ATTACHMENT_UNUSEDthen the clear has no effect. -
clearValueis the color or depth/stencil value to clear the attachment to, as described in Clear Values below.
No memory barriers are needed between vkCmdClearAttachments and
preceding or subsequent draw or attachment clear commands in the same
subpass.
The vkCmdClearAttachments command is not affected by the bound
pipeline state.
Attachments can also be cleared at the beginning of a render pass instance
by setting loadOp (or stencilLoadOp) of
VkAttachmentDescription to VK_ATTACHMENT_LOAD_OP_CLEAR, as
described for vkCreateRenderPass.
17.3. Clear Values
The VkClearColorValue structure is defined as:
typedef union VkClearColorValue {
float float32[4];
int32_t int32[4];
uint32_t uint32[4];
} VkClearColorValue;
-
float32are the color clear values when the format of the image or attachment is one of the formats in the Interpretation of Numeric Format table other than signed integer (SINT) or unsigned integer (UINT). Floating point values are automatically converted to the format of the image, with the clear value being treated as linear if the image is sRGB. -
int32are the color clear values when the format of the image or attachment is signed integer (SINT). Signed integer values are converted to the format of the image by casting to the smaller type (with negative 32-bit values mapping to negative values in the smaller type). If the integer clear value is not representable in the target type (e.g. would overflow in conversion to that type), the clear value is undefined. -
uint32are the color clear values when the format of the image or attachment is unsigned integer (UINT). Unsigned integer values are converted to the format of the image by casting to the integer type with fewer bits.
The four array elements of the clear color map to R, G, B, and A components of image formats, in order.
If the image has more than one sample, the same value is written to all samples for any pixels being cleared.
The VkClearDepthStencilValue structure is defined as:
typedef struct VkClearDepthStencilValue {
float depth;
uint32_t stencil;
} VkClearDepthStencilValue;
-
depthis the clear value for the depth aspect of the depth/stencil attachment. It is a floating-point value which is automatically converted to the attachment’s format. -
stencilis the clear value for the stencil aspect of the depth/stencil attachment. It is a 32-bit integer value which is converted to the attachment’s format by taking the appropriate number of LSBs.
The VkClearValue union is defined as:
typedef union VkClearValue {
VkClearColorValue color;
VkClearDepthStencilValue depthStencil;
} VkClearValue;
-
colorspecifies the color image clear values to use when clearing a color image or attachment. -
depthStencilspecifies the depth and stencil clear values to use when clearing a depth/stencil image or attachment.
This union is used where part of the API requires either color or depth/stencil clear values, depending on the attachment, and defines the initial clear values in the VkRenderPassBeginInfo structure.
17.4. Filling Buffers
To clear buffer data, call:
void vkCmdFillBuffer(
VkCommandBuffer commandBuffer,
VkBuffer dstBuffer,
VkDeviceSize dstOffset,
VkDeviceSize size,
uint32_t data);
-
commandBufferis the command buffer into which the command will be recorded. -
dstBufferis the buffer to be filled. -
dstOffsetis the byte offset into the buffer at which to start filling, and must be a multiple of 4. -
sizeis the number of bytes to fill, and must be either a multiple of 4, orVK_WHOLE_SIZEto fill the range fromoffsetto the end of the buffer. IfVK_WHOLE_SIZEis used and the remaining size of the buffer is not a multiple of 4, then the nearest smaller multiple is used. -
datais the 4-byte word written repeatedly to the buffer to fillsizebytes of data. The data word is written to memory according to the host endianness.
vkCmdFillBuffer is treated as “transfer” operation for the purposes
of synchronization barriers.
The VK_BUFFER_USAGE_TRANSFER_DST_BIT must be specified in usage
of VkBufferCreateInfo in order for the buffer to be compatible with
vkCmdFillBuffer.
17.5. Updating Buffers
To update buffer data inline in a command buffer, call:
void vkCmdUpdateBuffer(
VkCommandBuffer commandBuffer,
VkBuffer dstBuffer,
VkDeviceSize dstOffset,
VkDeviceSize dataSize,
const void* pData);
-
commandBufferis the command buffer into which the command will be recorded. -
dstBufferis a handle to the buffer to be updated. -
dstOffsetis the byte offset into the buffer to start updating, and must be a multiple of 4. -
dataSizeis the number of bytes to update, and must be a multiple of 4. -
pDatais a pointer to the source data for the buffer update, and must be at leastdataSizebytes in size.
dataSize must be less than or equal to 65536 bytes.
For larger updates, applications can use buffer to buffer
copies.
|
Note
Buffer updates performed with The additional cost of this functionality compared to buffer to buffer copies means it is only recommended for very small amounts of data, and is why it is limited to only 65536 bytes. Applications can work around this by issuing multiple
|
The source data is copied from the user pointer to the command buffer when the command is called.
vkCmdUpdateBuffer is only allowed outside of a render pass.
This command is treated as “transfer” operation, for the purposes of
synchronization barriers.
The VK_BUFFER_USAGE_TRANSFER_DST_BIT must be specified in usage
of VkBufferCreateInfo in order for the buffer to be compatible with
vkCmdUpdateBuffer.
|
Note
The |
18. Copy Commands
An application can copy buffer and image data using several methods
depending on the type of data transfer.
Data can be copied between buffer objects with vkCmdCopyBuffer and a
portion of an image can be copied to another image with
vkCmdCopyImage.
Image data can also be copied to and from buffer memory using
vkCmdCopyImageToBuffer and vkCmdCopyBufferToImage.
Image data can be blitted (with or without scaling and filtering) with
vkCmdBlitImage.
Multisampled images can be resolved to a non-multisampled image with
vkCmdResolveImage.
18.1. Common Operation
The following valid usage rules apply to all copy commands:
-
Copy commands must be recorded outside of a render pass instance.
-
The set of all bytes bound to all the source regions must not overlap the set of all bytes bound to the destination regions.
-
The set of all bytes bound to each destination region must not overlap the set of all bytes bound to another destination region.
-
Copy regions must be non-empty.
-
Regions must not extend outside the bounds of the buffer or image level, except that regions of compressed images can extend as far as the dimension of the image level rounded up to a complete compressed texel block.
-
Source image subresources must be in either the
VK_IMAGE_LAYOUT_GENERALorVK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMALlayout. Destination image subresources must be in theVK_IMAGE_LAYOUT_SHARED_PRESENT_KHR,VK_IMAGE_LAYOUT_GENERALorVK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMALlayout. As a consequence, if an image subresource is used as both source and destination of a copy, it must be in theVK_IMAGE_LAYOUT_GENERALlayout. -
Source images must use a format that supports
VK_FORMAT_FEATURE_TRANSFER_SRC_BIT, which is indicated byVkAndroidHardwareBufferFormatPropertiesANDROID::formatFeaturesreturned by vkGetAndroidHardwareBufferPropertiesANDROID for external format images, or byVkFormatProperties::linearTilingFeaturesorVkFormatProperties::optimalTilingFeaturesreturned byvkGetPhysicalDeviceFormatPropertiesfor non-external format linearly or optimally tiled images, respectively -
Destination images must use a format that supports
VK_FORMAT_FEATURE_TRANSFER_DST_BIT, which is indicated byVkAndroidHardwareBufferFormatPropertiesANDROID::formatFeaturesreturned by vkGetAndroidHardwareBufferPropertiesANDROID for external format images, or byVkFormatProperties::linearTilingFeaturesorVkFormatProperties::optimalTilingFeaturesreturned byvkGetPhysicalDeviceFormatPropertiesfor non-external format linearly or optimally tiled images, respectively -
Source images must have been created with the
VK_IMAGE_USAGE_TRANSFER_SRC_BITusage bit enabled and destination images must have been created with theVK_IMAGE_USAGE_TRANSFER_DST_BITusage bit enabled. -
Source buffers must have been created with the
VK_BUFFER_USAGE_TRANSFER_SRC_BITusage bit enabled and destination buffers must have been created with theVK_BUFFER_USAGE_TRANSFER_DST_BITusage bit enabled.
All copy commands are treated as “transfer” operations for the purposes of synchronization barriers.
18.2. Copying Data Between Buffers
To copy data between buffer objects, call:
void vkCmdCopyBuffer(
VkCommandBuffer commandBuffer,
VkBuffer srcBuffer,
VkBuffer dstBuffer,
uint32_t regionCount,
const VkBufferCopy* pRegions);
-
commandBufferis the command buffer into which the command will be recorded. -
srcBufferis the source buffer. -
dstBufferis the destination buffer. -
regionCountis the number of regions to copy. -
pRegionsis a pointer to an array of VkBufferCopy structures specifying the regions to copy.
Each region in pRegions is copied from the source buffer to the same
region of the destination buffer.
srcBuffer and dstBuffer can be the same buffer or alias the
same memory, but the result is undefined if the copy regions overlap in
memory.
The VkBufferCopy structure is defined as:
typedef struct VkBufferCopy {
VkDeviceSize srcOffset;
VkDeviceSize dstOffset;
VkDeviceSize size;
} VkBufferCopy;
-
srcOffsetis the starting offset in bytes from the start ofsrcBuffer. -
dstOffsetis the starting offset in bytes from the start ofdstBuffer. -
sizeis the number of bytes to copy.
18.3. Copying Data Between Images
vkCmdCopyImage performs image copies in a similar manner to a host
memcpy.
It does not perform general-purpose conversions such as scaling, resizing,
blending, color-space conversion, or format conversions.
Rather, it simply copies raw image data.
vkCmdCopyImage can copy between images with different formats,
provided the formats are compatible as defined below.
To copy data between image objects, call:
void vkCmdCopyImage(
VkCommandBuffer commandBuffer,
VkImage srcImage,
VkImageLayout srcImageLayout,
VkImage dstImage,
VkImageLayout dstImageLayout,
uint32_t regionCount,
const VkImageCopy* pRegions);
-
commandBufferis the command buffer into which the command will be recorded. -
srcImageis the source image. -
srcImageLayoutis the current layout of the source image subresource. -
dstImageis the destination image. -
dstImageLayoutis the current layout of the destination image subresource. -
regionCountis the number of regions to copy. -
pRegionsis a pointer to an array of VkImageCopy structures specifying the regions to copy.
Each region in pRegions is copied from the source image to the same
region of the destination image.
srcImage and dstImage can be the same image or alias the same
memory.
The formats of srcImage and dstImage must be compatible.
Formats are considered compatible if their element size is the same between
both formats.
For example, VK_FORMAT_R8G8B8A8_UNORM is compatible with
VK_FORMAT_R32_UINT because both texels are 4 bytes in size.
Depth/stencil formats must match exactly.
If the format of srcImage or dstImage is a
multi-planar image
format, regions of each plane to be copied must be specified separately
using the srcSubresource and dstSubresource members of the
VkImageCopy structure.
In this case, the aspectMask of the srcSubresource or
dstSubresource that refers to the multi-planar image must be
VK_IMAGE_ASPECT_PLANE_0_BIT, VK_IMAGE_ASPECT_PLANE_1_BIT, or
VK_IMAGE_ASPECT_PLANE_2_BIT.
For the purposes of vkCmdCopyImage, each plane of a multi-planar image
is treated as having the format listed in
Compatible formats of planes of multi-planar formats for the plane identified by the
aspectMask of the corresponding subresource.
This applies both to VkFormat and to coordinates used in the copy,
which correspond to texels in the plane rather than how these texels map
to coordinates in the image as a whole.
|
Note
For example, the |
vkCmdCopyImage allows copying between size-compatible compressed and
uncompressed internal formats.
Formats are size-compatible if the element size of the uncompressed format
is equal to the element size (compressed texel block size) of the compressed
format.
Such a copy does not perform on-the-fly compression or decompression.
When copying from an uncompressed format to a compressed format, each texel
of uncompressed data of the source image is copied as a raw value to the
corresponding compressed texel block of the destination image.
When copying from a compressed format to an uncompressed format, each
compressed texel block of the source image is copied as a raw value to the
corresponding texel of uncompressed data in the destination image.
Thus, for example, it is legal to copy between a 128-bit uncompressed format
and a compressed format which has a 128-bit sized compressed texel block
representing 4×4 texels (using 8 bits per texel), or between a 64-bit
uncompressed format and a compressed format which has a 64-bit sized
compressed texel block representing 4×4 texels (using 4 bits per
texel).
When copying between compressed and uncompressed formats the extent
members represent the texel dimensions of the source image and not the
destination.
When copying from a compressed image to an uncompressed image the image
texel dimensions written to the uncompressed image will be source extent
divided by the compressed texel block dimensions.
When copying from an uncompressed image to a compressed image the image
texel dimensions written to the compressed image will be the source extent
multiplied by the compressed texel block dimensions.
In both cases the number of bytes read and the number of bytes written will
be identical.
Copying to or from block-compressed images is typically done in multiples of
the compressed texel block size.
For this reason the extent must be a multiple of the compressed texel
block dimension.
There is one exception to this rule which is required to handle compressed
images created with dimensions that are not a multiple of the compressed
texel block dimensions: if the srcImage is compressed, then:
-
If
extent.widthis not a multiple of the compressed texel block width, then (extent.width+srcOffset.x) must equal the image subresource width. -
If
extent.heightis not a multiple of the compressed texel block height, then (extent.height+srcOffset.y) must equal the image subresource height. -
If
extent.depthis not a multiple of the compressed texel block depth, then (extent.depth+srcOffset.z) must equal the image subresource depth.
Similarly, if the dstImage is compressed, then:
-
If
extent.widthis not a multiple of the compressed texel block width, then (extent.width+dstOffset.x) must equal the image subresource width. -
If
extent.heightis not a multiple of the compressed texel block height, then (extent.height+dstOffset.y) must equal the image subresource height. -
If
extent.depthis not a multiple of the compressed texel block depth, then (extent.depth+dstOffset.z) must equal the image subresource depth.
This allows the last compressed texel block of the image in each non-multiple dimension to be included as a source or destination of the copy.
“_422” image formats that are not
multi-planar are
treated as having a 2×1 compressed texel block for the purposes of
these rules.
vkCmdCopyImage can be used to copy image data between multisample
images, but both images must have the same number of samples.
The VkImageCopy structure is defined as:
typedef struct VkImageCopy {
VkImageSubresourceLayers srcSubresource;
VkOffset3D srcOffset;
VkImageSubresourceLayers dstSubresource;
VkOffset3D dstOffset;
VkExtent3D extent;
} VkImageCopy;
-
srcSubresourceanddstSubresourceare VkImageSubresourceLayers structures specifying the image subresources of the images used for the source and destination image data, respectively. -
srcOffsetanddstOffsetselect the initialx,y, andzoffsets in texels of the sub-regions of the source and destination image data. -
extentis the size in texels of the image to copy inwidth,heightanddepth.
For VK_IMAGE_TYPE_3D images, copies are performed slice by slice
starting with the z member of the srcOffset or dstOffset,
and copying depth slices.
For images with multiple layers, copies are performed layer by layer
starting with the baseArrayLayer member of the srcSubresource or
dstSubresource and copying layerCount layers.
Image data can be copied between images with different image types.
If one image is VK_IMAGE_TYPE_3D and the other image is
VK_IMAGE_TYPE_2D with multiple layers, then each slice is copied to or
from a different layer.
Copies involving a multi-planar image format specify the region to be copied in terms of the
plane to be copied, not the coordinates of the multi-planar image.
This means that copies accessing the R/B planes of “_422” format
images must fit the copied region within half the width of the parent
image, and that copies accessing the R/B planes of “_420” format
images must fit the copied region within half the width and
height of the parent image.
The VkImageSubresourceLayers structure is defined as:
typedef struct VkImageSubresourceLayers {
VkImageAspectFlags aspectMask;
uint32_t mipLevel;
uint32_t baseArrayLayer;
uint32_t layerCount;
} VkImageSubresourceLayers;
-
aspectMaskis a combination of VkImageAspectFlagBits, selecting the color, depth and/or stencil aspects to be copied. -
mipLevelis the mipmap level to copy from. -
baseArrayLayerandlayerCountare the starting layer and number of layers to copy.
18.4. Copying Data Between Buffers and Images
To copy data from a buffer object to an image object, call:
void vkCmdCopyBufferToImage(
VkCommandBuffer commandBuffer,
VkBuffer srcBuffer,
VkImage dstImage,
VkImageLayout dstImageLayout,
uint32_t regionCount,
const VkBufferImageCopy* pRegions);
-
commandBufferis the command buffer into which the command will be recorded. -
srcBufferis the source buffer. -
dstImageis the destination image. -
dstImageLayoutis the layout of the destination image subresources for the copy. -
regionCountis the number of regions to copy. -
pRegionsis a pointer to an array of VkBufferImageCopy structures specifying the regions to copy.
Each region in pRegions is copied from the specified region of the
source buffer to the specified region of the destination image.
If the format of dstImage is a
multi-planar image
format), regions of each plane to be a target of a copy must be specified
separately using the pRegions member of the VkBufferImageCopy
structure.
In this case, the aspectMask of imageSubresource must be
VK_IMAGE_ASPECT_PLANE_0_BIT, VK_IMAGE_ASPECT_PLANE_1_BIT, or
VK_IMAGE_ASPECT_PLANE_2_BIT.
For the purposes of vkCmdCopyBufferToImage, each plane of a
multi-planar image is treated as having the format listed in
Compatible formats of planes of multi-planar formats for the plane identified by the
aspectMask of the corresponding subresource.
This applies both to VkFormat and to coordinates used in the copy,
which correspond to texels in the plane rather than how these texels map
to coordinates in the image as a whole.
To copy data from an image object to a buffer object, call:
void vkCmdCopyImageToBuffer(
VkCommandBuffer commandBuffer,
VkImage srcImage,
VkImageLayout srcImageLayout,
VkBuffer dstBuffer,
uint32_t regionCount,
const VkBufferImageCopy* pRegions);
-
commandBufferis the command buffer into which the command will be recorded. -
srcImageis the source image. -
srcImageLayoutis the layout of the source image subresources for the copy. -
dstBufferis the destination buffer. -
regionCountis the number of regions to copy. -
pRegionsis a pointer to an array of VkBufferImageCopy structures specifying the regions to copy.
Each region in pRegions is copied from the specified region of the
source image to the specified region of the destination buffer.
If the VkFormat of srcImage is a
multi-planar image
format, regions of each plane to be a source of a copy must be specified
separately using the pRegions member of the VkBufferImageCopy
structure.
In this case, the aspectMask of imageSubresource must be
VK_IMAGE_ASPECT_PLANE_0_BIT, VK_IMAGE_ASPECT_PLANE_1_BIT, or
VK_IMAGE_ASPECT_PLANE_2_BIT.
For the purposes of vkCmdCopyBufferToImage, each plane of a
multi-planar image is treated as having the format listed in
Compatible formats of planes of multi-planar formats for the plane identified by the
aspectMask of the corresponding subresource.
This applies both to VkFormat and to coordinates used in the copy,
which correspond to texels in the plane rather than how these texels map
to coordinates in the image as a whole.
For both vkCmdCopyBufferToImage and vkCmdCopyImageToBuffer, each
element of pRegions is a structure defined as:
typedef struct VkBufferImageCopy {
VkDeviceSize bufferOffset;
uint32_t bufferRowLength;
uint32_t bufferImageHeight;
VkImageSubresourceLayers imageSubresource;
VkOffset3D imageOffset;
VkExtent3D imageExtent;
} VkBufferImageCopy;
-
bufferOffsetis the offset in bytes from the start of the buffer object where the image data is copied from or to. -
bufferRowLengthandbufferImageHeightspecify the data in buffer memory as a subregion of a larger two- or three-dimensional image, and control the addressing calculations of data in buffer memory. If either of these values is zero, that aspect of the buffer memory is considered to be tightly packed according to theimageExtent. -
imageSubresourceis a VkImageSubresourceLayers used to specify the specific image subresources of the image used for the source or destination image data. -
imageOffsetselects the initialx,y,zoffsets in texels of the sub-region of the source or destination image data. -
imageExtentis the size in texels of the image to copy inwidth,heightanddepth.
When copying to or from a depth or stencil aspect, the data in buffer memory uses a layout that is a (mostly) tightly packed representation of the depth or stencil data. Specifically:
-
data copied to or from the stencil aspect of any depth/stencil format is tightly packed with one
VK_FORMAT_S8_UINTvalue per texel. -
data copied to or from the depth aspect of a
VK_FORMAT_D16_UNORMorVK_FORMAT_D16_UNORM_S8_UINTformat is tightly packed with oneVK_FORMAT_D16_UNORMvalue per texel. -
data copied to or from the depth aspect of a
VK_FORMAT_D32_SFLOATorVK_FORMAT_D32_SFLOAT_S8_UINTformat is tightly packed with oneVK_FORMAT_D32_SFLOATvalue per texel. -
data copied to or from the depth aspect of a
VK_FORMAT_X8_D24_UNORM_PACK32orVK_FORMAT_D24_UNORM_S8_UINTformat is packed with one 32-bit word per texel with the D24 value in the LSBs of the word, and undefined values in the eight MSBs.
|
Note
To copy both the depth and stencil aspects of a depth/stencil format, two
entries in |
Because depth or stencil aspect buffer to image copies may require format conversions on some implementations, they are not supported on queues that do not support graphics. When copying to a depth aspect, the data in buffer memory must be in the the range [0,1] or undefined results occur.
Copies are done layer by layer starting with image layer
baseArrayLayer member of imageSubresource.
layerCount layers are copied from the source image or to the
destination image.
18.4.1. Buffer and Image Addressing
Pseudocode for image/buffer addressing is:
rowLength = region->bufferRowLength;
if (rowLength == 0)
rowLength = region->imageExtent.width;
imageHeight = region->bufferImageHeight;
if (imageHeight == 0)
imageHeight = region->imageExtent.height;
elementSize = <element size of the format of the src/dstImage>;
address of (x,y,z) = region->bufferOffset + (((z * imageHeight) + y) * rowLength + x) * elementSize;
where x,y,z range from (0,0,0) to region->imageExtent.{width,height,depth}.
Note that imageOffset does not affect addressing calculations for
buffer memory.
Instead, bufferOffset can be used to select the starting address in
buffer memory.
For block-compression formats, all parameters are still specified in texels rather than compressed texel blocks, but the addressing math operates on whole compressed texel blocks. Pseudocode for compressed copy addressing is:
rowLength = region->bufferRowLength;
if (rowLength == 0)
rowLength = region->imageExtent.width;
imageHeight = region->bufferImageHeight;
if (imageHeight == 0)
imageHeight = region->imageExtent.height;
compressedTexelBlockSizeInBytes = <compressed texel block size taken from the src/dstImage>;
rowLength /= compressedTexelBlockWidth;
imageHeight /= compressedTexelBlockHeight;
address of (x,y,z) = region->bufferOffset + (((z * imageHeight) + y) * rowLength + x) * compressedTexelBlockSizeInBytes;
where x,y,z range from (0,0,0) to region->imageExtent.{width/compressedTexelBlockWidth,height/compressedTexelBlockHeight,depth/compressedTexelBlockDepth}.
Copying to or from block-compressed images is typically done in multiples of
the compressed texel block size.
For this reason the imageExtent must be a multiple of the compressed
texel block dimension.
There is one exception to this rule which is required to handle compressed
images created with dimensions that are not a multiple of the compressed
texel block dimensions:
-
If
imageExtent.widthis not a multiple of the compressed texel block width, then (imageExtent.width+imageOffset.x) must equal the image subresource width. -
If
imageExtent.heightis not a multiple of the compressed texel block height, then (imageExtent.height+imageOffset.y) must equal the image subresource height. -
If
imageExtent.depthis not a multiple of the compressed texel block depth, then (imageExtent.depth+imageOffset.z) must equal the image subresource depth.
This allows the last compressed texel block of the image in each non-multiple dimension to be included as a source or destination of the copy.
18.5. Image Copies with Scaling
To copy regions of a source image into a destination image, potentially performing format conversion, arbitrary scaling, and filtering, call:
void vkCmdBlitImage(
VkCommandBuffer commandBuffer,
VkImage srcImage,
VkImageLayout srcImageLayout,
VkImage dstImage,
VkImageLayout dstImageLayout,
uint32_t regionCount,
const VkImageBlit* pRegions,
VkFilter filter);
-
commandBufferis the command buffer into which the command will be recorded. -
srcImageis the source image. -
srcImageLayoutis the layout of the source image subresources for the blit. -
dstImageis the destination image. -
dstImageLayoutis the layout of the destination image subresources for the blit. -
regionCountis the number of regions to blit. -
pRegionsis a pointer to an array of VkImageBlit structures specifying the regions to blit. -
filteris a VkFilter specifying the filter to apply if the blits require scaling.
vkCmdBlitImage must not be used for multisampled source or
destination images.
Use vkCmdResolveImage for this purpose.
As the sizes of the source and destination extents can differ in any dimension, texels in the source extent are scaled and filtered to the destination extent. Scaling occurs via the following operations:
-
For each destination texel, the integer coordinate of that texel is converted to an unnormalized texture coordinate, using the effective inverse of the equations described in unnormalized to integer conversion:
-
ubase = i + ½
-
vbase = j + ½
-
wbase = k + ½
-
-
These base coordinates are then offset by the first destination offset:
-
uoffset = ubase - xdst0
-
voffset = vbase - ydst0
-
woffset = wbase - zdst0
-
aoffset = a -
baseArrayCountdst
-
-
The scale is determined from the source and destination regions, and applied to the offset coordinates:
-
scale_u = (xsrc1 - xsrc0) / (xdst1 - xdst0)
-
scale_v = (ysrc1 - ysrc0) / (ydst1 - ydst0)
-
scale_w = (zsrc1 - zsrc0) / (zdst1 - zdst0)
-
uscaled = uoffset * scaleu
-
vscaled = voffset * scalev
-
wscaled = woffset * scalew
-
-
Finally the source offset is added to the scaled coordinates, to determine the final unnormalized coordinates used to sample from
srcImage:-
u = uscaled + xsrc0
-
v = vscaled + ysrc0
-
w = wscaled + zsrc0
-
q =
mipLevel -
a = aoffset +
baseArrayCountsrc
-
These coordinates are used to sample from the source image, as described in
Image Operations chapter, with the filter mode equal to that
of filter, a mipmap mode of VK_SAMPLER_MIPMAP_MODE_NEAREST and
an address mode of VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE.
Implementations must clamp at the edge of the source image, and may
additionally clamp to the edge of the source region.
|
Note
Due to allowable rounding errors in the generation of the source texture coordinates, it is not always possible to guarantee exactly which source texels will be sampled for a given blit. As rounding errors are implementation dependent, the exact results of a blitting operation are also implementation dependent. |
Blits are done layer by layer starting with the baseArrayLayer member
of srcSubresource for the source and dstSubresource for the
destination.
layerCount layers are blitted to the destination image.
3D textures are blitted slice by slice.
Slices in the source region bounded by srcOffsets[0].z and
srcOffsets[1].z are copied to slices in the destination region
bounded by dstOffsets[0].z and dstOffsets[1].z.
For each destination slice, a source z coordinate is linearly interpolated
between srcOffsets[0].z and srcOffsets[1].z.
If the filter parameter is VK_FILTER_LINEAR then the value
sampled from the source image is taken by doing linear filtering using the
interpolated z coordinate.
If filter parameter is VK_FILTER_NEAREST then value sampled from
the source image is taken from the single nearest slice (with undefined
rounding mode).
The following filtering and conversion rules apply:
-
Integer formats can only be converted to other integer formats with the same signedness.
-
No format conversion is supported between depth/stencil images. The formats must match.
-
Format conversions on unorm, snorm, unscaled and packed float formats of the copied aspect of the image are performed by first converting the pixels to float values.
-
For sRGB source formats, nonlinear RGB values are converted to linear representation prior to filtering.
-
After filtering, the float values are first clamped and then cast to the destination image format. In case of sRGB destination format, linear RGB values are converted to nonlinear representation before writing the pixel to the image.
Signed and unsigned integers are converted by first clamping to the representable range of the destination format, then casting the value.
The VkImageBlit structure is defined as:
typedef struct VkImageBlit {
VkImageSubresourceLayers srcSubresource;
VkOffset3D srcOffsets[2];
VkImageSubresourceLayers dstSubresource;
VkOffset3D dstOffsets[2];
} VkImageBlit;
-
srcSubresourceis the subresource to blit from. -
srcOffsetsis an array of two VkOffset3D structures specifying the bounds of the source region withinsrcSubresource. -
dstSubresourceis the subresource to blit into. -
dstOffsetsis an array of two VkOffset3D structures specifying the bounds of the destination region withindstSubresource.
For each element of the pRegions array, a blit operation is performed
the specified source and destination regions.
18.6. Resolving Multisample Images
To resolve a multisample image to a non-multisample image, call:
void vkCmdResolveImage(
VkCommandBuffer commandBuffer,
VkImage srcImage,
VkImageLayout srcImageLayout,
VkImage dstImage,
VkImageLayout dstImageLayout,
uint32_t regionCount,
const VkImageResolve* pRegions);
-
commandBufferis the command buffer into which the command will be recorded. -
srcImageis the source image. -
srcImageLayoutis the layout of the source image subresources for the resolve. -
dstImageis the destination image. -
dstImageLayoutis the layout of the destination image subresources for the resolve. -
regionCountis the number of regions to resolve. -
pRegionsis a pointer to an array of VkImageResolve structures specifying the regions to resolve.
During the resolve the samples corresponding to each pixel location in the source are converted to a single sample before being written to the destination. If the source formats are floating-point or normalized types, the sample values for each pixel are resolved in an implementation-dependent manner. If the source formats are integer types, a single sample’s value is selected for each pixel.
srcOffset and dstOffset select the initial x, y, and
z offsets in texels of the sub-regions of the source and destination
image data.
extent is the size in texels of the source image to resolve in
width, height and depth.
Resolves are done layer by layer starting with baseArrayLayer member
of srcSubresource for the source and dstSubresource for the
destination.
layerCount layers are resolved to the destination image.
The VkImageResolve structure is defined as:
typedef struct VkImageResolve {
VkImageSubresourceLayers srcSubresource;
VkOffset3D srcOffset;
VkImageSubresourceLayers dstSubresource;
VkOffset3D dstOffset;
VkExtent3D extent;
} VkImageResolve;
-
srcSubresourceanddstSubresourceare VkImageSubresourceLayers structures specifying the image subresources of the images used for the source and destination image data, respectively. Resolve of depth/stencil images is not supported. -
srcOffsetanddstOffsetselect the initialx,y, andzoffsets in texels of the sub-regions of the source and destination image data. -
extentis the size in texels of the source image to resolve inwidth,heightanddepth.
18.7. Buffer Markers
To write a 32-bit marker value into a buffer as a pipelined operation, call:
void vkCmdWriteBufferMarkerAMD(
VkCommandBuffer commandBuffer,
VkPipelineStageFlagBits pipelineStage,
VkBuffer dstBuffer,
VkDeviceSize dstOffset,
uint32_t marker);
-
commandBufferis the command buffer into which the command will be recorded. -
pipelineStageis one of the VkPipelineStageFlagBits values, specifying the pipeline stage whose completion triggers the marker write. -
dstBufferis the buffer where the marker will be written to. -
dstOffsetis the byte offset into the buffer where the marker will be written to. -
markeris the 32-bit value of the marker.
The command will write the 32-bit marker value into the buffer only after
all preceding commands have finished executing up to at least the specified
pipeline stage.
This includes the completion of other preceding
vkCmdWriteBufferMarkerAMD commands so long as their specified pipeline
stages occur either at the same time or earlier than this command’s
specified pipelineStage.
While consecutive buffer marker writes with the same pipelineStage
parameter are implicitly complete in submission order, memory and execution
dependencies between buffer marker writes and other operations must still be
explicitly ordered using synchronization commands.
The access scope for buffer marker writes falls under the
VK_ACCESS_TRANSFER_WRITE_BIT, and the pipeline stages for identifying
the synchronization scope must include both pipelineStage and
VK_PIPELINE_STAGE_TRANSFER_BIT.
|
Note
Similar to |
|
Note
Implementations may only support a limited number of pipelined marker write operations in flight at a given time, thus excessive number of marker write operations may degrade command execution performance. |
19. Drawing Commands
Drawing commands (commands with Draw in the name) provoke work in a
graphics pipeline.
Drawing commands are recorded into a command buffer and when executed by a
queue, will produce work which executes according to the bound graphics
pipeline.
A graphics pipeline must be bound to a command buffer before any drawing
commands are recorded in that command buffer.
Each draw is made up of zero or more vertices and zero or more instances,
which are processed by the device and result in the assembly of primitives.
Primitives are assembled according to the pInputAssemblyState member
of the VkGraphicsPipelineCreateInfo structure, which is of type
VkPipelineInputAssemblyStateCreateInfo:
typedef struct VkPipelineInputAssemblyStateCreateInfo {
VkStructureType sType;
const void* pNext;
VkPipelineInputAssemblyStateCreateFlags flags;
VkPrimitiveTopology topology;
VkBool32 primitiveRestartEnable;
} VkPipelineInputAssemblyStateCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
topologyis a VkPrimitiveTopology defining the primitive topology, as described below. -
primitiveRestartEnablecontrols whether a special vertex index value is treated as restarting the assembly of primitives. This enable only applies to indexed draws (vkCmdDrawIndexed and vkCmdDrawIndexedIndirect), and the special index value is either 0xFFFFFFFF when theindexTypeparameter ofvkCmdBindIndexBufferis equal toVK_INDEX_TYPE_UINT32, or 0xFFFF whenindexTypeis equal toVK_INDEX_TYPE_UINT16. Primitive restart is not allowed for “list” topologies.
Restarting the assembly of primitives discards the most recent index values
if those elements formed an incomplete primitive, and restarts the primitive
assembly using the subsequent indices, but only assembling the immediately
following element through the end of the originally specified elements.
The primitive restart index value comparison is performed before adding the
vertexOffset value to the index value.
typedef VkFlags VkPipelineInputAssemblyStateCreateFlags;
VkPipelineInputAssemblyStateCreateFlags is a bitmask type for setting
a mask, but is currently reserved for future use.
19.1. Primitive Topologies
Primitive topology determines how consecutive vertices are organized into primitives, and determines the type of primitive that is used at the beginning of the graphics pipeline. The effective topology for later stages of the pipeline is altered by tessellation or geometry shading (if either is in use) and depends on the execution modes of those shaders. Supported topologies are defined by VkPrimitiveTopology and include:
typedef enum VkPrimitiveTopology {
VK_PRIMITIVE_TOPOLOGY_POINT_LIST = 0,
VK_PRIMITIVE_TOPOLOGY_LINE_LIST = 1,
VK_PRIMITIVE_TOPOLOGY_LINE_STRIP = 2,
VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST = 3,
VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP = 4,
VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN = 5,
VK_PRIMITIVE_TOPOLOGY_LINE_LIST_WITH_ADJACENCY = 6,
VK_PRIMITIVE_TOPOLOGY_LINE_STRIP_WITH_ADJACENCY = 7,
VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST_WITH_ADJACENCY = 8,
VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP_WITH_ADJACENCY = 9,
VK_PRIMITIVE_TOPOLOGY_PATCH_LIST = 10,
} VkPrimitiveTopology;
Each primitive topology, and its construction from a list of vertices, is summarized below with a supporting diagram. In each diagram, the numbered points show the sequencing of vertices in order within the vertex arrays; however the positions chosen are arbitrary and for illustration only. Vertices connected with solid lines belong to the main primitives. In the primitive types with adjacency, the vertices connected by dashed lines are the adjacent vertices that are accessible in a geometry shader.
|
Note
The terminology “vertex i ” means “the vertex with index i in the ordered list of vertices defining this primitive”. |
|
Note
Depending on the polygon mode, a polygon
primitive generated from a drawing command with |
19.1.1. Point Lists
A series of individual points are specified with topology
VK_PRIMITIVE_TOPOLOGY_POINT_LIST.
Each vertex defines a separate point.
19.1.2. Line Lists
Lists of line segments, with each segment defined by a pair of vertices, are
specified with topology VK_PRIMITIVE_TOPOLOGY_LINE_LIST.
The first two vertices define the first segment, with subsequent pairs of
vertices each defining one more segment.
If the number of vertices is odd, then the last vertex is ignored.
19.1.3. Line Strips
A series of one or more connected line segments are specified with
topology VK_PRIMITIVE_TOPOLOGY_LINE_STRIP.
In this case, the first vertex specifies the first segment’s start point
while the second vertex specifies the first segment’s endpoint and the
second segment’s start point.
In general, vertex i (for i > 0) specifies the beginning of the
ith segment and the end of the previous segment.
The last vertex specifies the end of the last segment.
If only one vertex is specified, then no primitive is generated.
19.1.4. Triangle Lists
Lists of separate triangles are specified with topology
VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST.
In this case, vertices 3 i, 3 i + 1, and 3 i + 2
(in that order) determine a triangle for each i = 0, 1, …, n-1,
where there are 3 n + k vertices drawn.
k is either 0, 1, or 2; if k is not zero, the final k
vertices are ignored.
19.1.5. Triangle Strips
A triangle strip is a series of triangles connected along shared edges, and
is specified with topology VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP.
In this case, the first three vertices define the first triangle, and their
order is significant.
Each subsequent vertex defines a new triangle using that point along with
the last two vertices from the previous triangle.
If fewer than three vertices are specified, no primitive is produced.
The order of vertices in successive triangles changes as shown in the figure
below, so that all triangle faces have the same orientation.
19.1.6. Triangle Fans
A triangle fan is specified with topology
VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN.
It is similar to a triangle strip, but changes the vertex replaced from the
previous triangle so that all triangles in the fan share a common vertex.
19.1.7. Line Lists With Adjacency
Lines with adjacency are specified with topology
VK_PRIMITIVE_TOPOLOGY_LINE_LIST_WITH_ADJACENCY, and are independent
line segments where each endpoint has a corresponding adjacent vertex that
is accessible in a geometry shader.
If a geometry shader is not active, the adjacent vertices are ignored.
A line segment is drawn from vertex 4 i + 1 to vertex 4 i + 2 for each i = 0, 1, …, n-1, where there are 4 n + k vertices. k is either 0, 1, 2, or 3; if k is not zero, the final k vertices are ignored. For line segment i, vertices 4 i and 4 i + 3 vertices are considered adjacent to vertices 4 i + 1 and 4 i + 2, respectively.
19.1.8. Line Strips With Adjacency
Line strips with adjacency are specified with topology
VK_PRIMITIVE_TOPOLOGY_LINE_STRIP_WITH_ADJACENCY and are similar to
line strips, except that each line segment has a pair of adjacent vertices
that are accessible in a geometry shader.
If a geometry shader is not active, the adjacent vertices are ignored.
A line segment is drawn from vertex i + 1 vertex to vertex i + 2 for each i = 0, 1, …, n-1, where there are n + 3 vertices. If there are fewer than four vertices, all vertices are ignored. For line segment i, vertices i and i + 3 are considered adjacent to vertices i + 1 and i + 2, respectively.
19.1.9. Triangle Lists With Adjacency
Triangles with adjacency are specified with topology
VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST_WITH_ADJACENCY, and are similar to
separate triangles except that each triangle edge has an adjacent vertex
that is accessible in a geometry shader.
If a geometry shader is not active, the adjacent vertices are ignored.
Vertices 6 i, 6 i + 2, and 6 i + 4 (in that order) determine a triangle for each i = 0, 1, …, n-1, where there are 6 n+k vertices. k is either 0, 1, 2, 3, 4, or 5; if k is non-zero, the final k vertices are ignored. For triangle i, vertices 6 i + 1, 6 i + 3, and 6 i + 5 vertices are considered adjacent to edges from vertex 6 i to 6 i + 2, from 6 i + 2 to 6 i + 4, and from 6 i + 4 to 6 i vertices, respectively.
19.1.10. Triangle Strips With Adjacency
Triangle strips with adjacency are specified with topology
VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP_WITH_ADJACENCY, and are similar
to triangle strips except that each triangle edge has an adjacent vertex
that is accessible in a geometry shader.
If a geometry shader is not active, the adjacent vertices are ignored.
In triangle strips with adjacency, n triangles are drawn where there are 2 (n + 2) + k vertices. k is either 0 or 1; if k is 1, the final vertex is ignored. If there are fewer than 6 vertices, the entire primitive is ignored.
The table below illustrates the vertices and order used to draw each triangle, and which vertices are considered adjacent to each edge of those triangles. Each triangle is drawn using the vertices whose numbers are in the 1st, 2nd, and 3rd columns under Primitive Vertices, in that order. The vertices in the 1/2, 2/3, and 3/1 columns under Adjacent Vertices are considered adjacent to the edges from the first to the second, from the second to the third, and from the third to the first vertex of the triangle, respectively. The six rows correspond to six cases: the first and only triangle (i = 0, n = 1), the first triangle of several (i = 0, n > 0), odd middle triangles (i = 1, 3, 5 …), even middle triangles (i = 2, 4, 6, …), and special cases for the last triangle, when i is either even or odd. For the purposes of this table, both the first vertex and first triangle are numbered 0.
| Primitive Vertices | Adjacent Vertices | |||||
|---|---|---|---|---|---|---|
Primitive |
1st |
2nd |
3rd |
1/2 |
2/3 |
3/1 |
only (i = 0, n = 1) |
0 |
2 |
4 |
1 |
5 |
3 |
first (i = 0) |
0 |
2 |
4 |
1 |
6 |
3 |
middle (i odd) |
2 i + 2 |
2 i |
2 i + 4 |
2 i-2 |
2 i + 3 |
2 i + 6 |
middle (i even) |
2 i |
2 i + 2 |
2 i + 4 |
2 i-2 |
2 i + 6 |
2 i + 3 |
last (i=n-1, i odd) |
2 i + 2 |
2 i |
2 i + 4 |
2 i-2 |
2 i + 3 |
2 i + 5 |
last (i=n-1, i even) |
2 i |
2 i + 2 |
2 i + 4 |
2 i-2 |
2 i + 5 |
2 i + 3 |
19.1.11. Separate Patches
Separate patches are specified with topology
VK_PRIMITIVE_TOPOLOGY_PATCH_LIST.
A patch is an ordered collection of vertices used for
primitive tessellation.
The vertices comprising a patch have no implied geometric ordering, and are
used by tessellation shaders and the fixed-function tessellator to generate
new point, line, or triangle primitives.
Each patch in the series has a fixed number of vertices, specified by the
patchControlPoints member of the
VkPipelineTessellationStateCreateInfo structure passed to
vkCreateGraphicsPipelines.
Once assembled and vertex shaded, these patches are provided as input to the
tessellation control shader stage.
If the number of vertices in a patch is given by v, vertices v × i through v × i + v - 1 (in that order) determine a patch for each i = 0, 1, …, n-1, where there are v × n + k vertices. k is in the range [0, v - 1]; if k is not zero, the final k vertices are ignored.
19.2. Primitive Order
Primitives generated by drawing commands progress through the stages of the graphics pipeline in primitive order. Primitive order is initially determined in the following way:
-
Submission order determines the initial ordering
-
For indirect draw commands, the order in which accessed instances of the VkDrawIndirectCommand are stored in
buffer, from lower indirect buffer addresses to higher addresses. -
If a draw command includes multiple instances, the order in which instances are executed, from lower numbered instances to higher.
-
The order in which primitives are specified by a draw command:
-
For non-indexed draws, from vertices with a lower numbered
vertexIndexto a higher numberedvertexIndex. -
For indexed draws, vertices sourced from a lower index buffer addresses to higher addresses.
-
Within this order implementations further sort primitives:
-
If tessellation shading is active, by an implementation-dependent order of new primitives generated by tessellation.
-
If geometry shading is active, by the order new primitives are generated by geometry shading.
-
If the polygon mode is not
VK_POLYGON_MODE_FILL, orVK_POLYGON_MODE_FILL_RECTANGLE_NV, by an implementation-dependent ordering of the new primitives generated within the original primitive.
Primitive order is later used to define rasterization order, which determines the order in which fragments output results to a framebuffer.
19.3. Programmable Primitive Shading
Once primitives are assembled, they proceed to the vertex shading stage of the pipeline. If the draw includes multiple instances, then the set of primitives is sent to the vertex shading stage multiple times, once for each instance.
It is undefined whether vertex shading occurs on vertices that are discarded as part of incomplete primitives, but if it does occur then it operates as if they were vertices in complete primitives and such invocations can have side effects.
Vertex shading receives two per-vertex inputs from the primitive assembly
stage - the vertexIndex and the instanceIndex.
How these values are generated is defined below, with each command.
Drawing commands fall roughly into two categories:
-
Non-indexed drawing commands present a sequential
vertexIndexto the vertex shader. The sequential index is generated automatically by the device (see Fixed-Function Vertex Processing for details on both specifying the vertex attributes indexed byvertexIndex, as well as binding vertex buffers containing those attributes to a command buffer). These commands are: -
Indexed drawing commands read index values from an index buffer and use this to compute the
vertexIndexvalue for the vertex shader. These commands are:
To bind an index buffer to a command buffer, call:
void vkCmdBindIndexBuffer(
VkCommandBuffer commandBuffer,
VkBuffer buffer,
VkDeviceSize offset,
VkIndexType indexType);
-
commandBufferis the command buffer into which the command is recorded. -
bufferis the buffer being bound. -
offsetis the starting offset in bytes withinbufferused in index buffer address calculations. -
indexTypeis a VkIndexType value specifying whether indices are treated as 16 bits or 32 bits.
Possible values of vkCmdBindIndexBuffer::indexType, specifying
the size of indices, are:
typedef enum VkIndexType {
VK_INDEX_TYPE_UINT16 = 0,
VK_INDEX_TYPE_UINT32 = 1,
} VkIndexType;
-
VK_INDEX_TYPE_UINT16specifies that indices are 16-bit unsigned integer values. -
VK_INDEX_TYPE_UINT32specifies that indices are 32-bit unsigned integer values.
The parameters for each drawing command are specified directly in the command or read from buffer memory, depending on the command. Drawing commands that source their parameters from buffer memory are known as indirect drawing commands.
All drawing commands interact with the Robust Buffer Access feature.
To record a non-indexed draw, call:
void vkCmdDraw(
VkCommandBuffer commandBuffer,
uint32_t vertexCount,
uint32_t instanceCount,
uint32_t firstVertex,
uint32_t firstInstance);
-
commandBufferis the command buffer into which the command is recorded. -
vertexCountis the number of vertices to draw. -
instanceCountis the number of instances to draw. -
firstVertexis the index of the first vertex to draw. -
firstInstanceis the instance ID of the first instance to draw.
When the command is executed, primitives are assembled using the current
primitive topology and vertexCount consecutive vertex indices with the
first vertexIndex value equal to firstVertex.
The primitives are drawn instanceCount times with instanceIndex
starting with firstInstance and increasing sequentially for each
instance.
The assembled primitives execute the bound graphics pipeline.
To record an indexed draw, call:
void vkCmdDrawIndexed(
VkCommandBuffer commandBuffer,
uint32_t indexCount,
uint32_t instanceCount,
uint32_t firstIndex,
int32_t vertexOffset,
uint32_t firstInstance);
-
commandBufferis the command buffer into which the command is recorded. -
indexCountis the number of vertices to draw. -
instanceCountis the number of instances to draw. -
firstIndexis the base index within the index buffer. -
vertexOffsetis the value added to the vertex index before indexing into the vertex buffer. -
firstInstanceis the instance ID of the first instance to draw.
When the command is executed, primitives are assembled using the current
primitive topology and indexCount vertices whose indices are retrieved
from the index buffer.
The index buffer is treated as an array of tightly packed unsigned integers
of size defined by the vkCmdBindIndexBuffer::indexType parameter
with which the buffer was bound.
The first vertex index is at an offset of firstIndex * indexSize
+ offset within the bound index buffer, where offset is the
offset specified by vkCmdBindIndexBuffer and indexSize is the
byte size of the type specified by indexType.
Subsequent index values are retrieved from consecutive locations in the
index buffer.
Indices are first compared to the primitive restart value, then zero
extended to 32 bits (if the indexType is VK_INDEX_TYPE_UINT16)
and have vertexOffset added to them, before being supplied as the
vertexIndex value.
The primitives are drawn instanceCount times with instanceIndex
starting with firstInstance and increasing sequentially for each
instance.
The assembled primitives execute the bound graphics pipeline.
To record a non-indexed indirect draw, call:
void vkCmdDrawIndirect(
VkCommandBuffer commandBuffer,
VkBuffer buffer,
VkDeviceSize offset,
uint32_t drawCount,
uint32_t stride);
-
commandBufferis the command buffer into which the command is recorded. -
bufferis the buffer containing draw parameters. -
offsetis the byte offset intobufferwhere parameters begin. -
drawCountis the number of draws to execute, and can be zero. -
strideis the byte stride between successive sets of draw parameters.
vkCmdDrawIndirect behaves similarly to vkCmdDraw except that the
parameters are read by the device from a buffer during execution.
drawCount draws are executed by the command, with parameters taken
from buffer starting at offset and increasing by stride
bytes for each successive draw.
The parameters of each draw are encoded in an array of
VkDrawIndirectCommand structures.
If drawCount is less than or equal to one, stride is ignored.
The VkDrawIndirectCommand structure is defined as:
typedef struct VkDrawIndirectCommand {
uint32_t vertexCount;
uint32_t instanceCount;
uint32_t firstVertex;
uint32_t firstInstance;
} VkDrawIndirectCommand;
-
vertexCountis the number of vertices to draw. -
instanceCountis the number of instances to draw. -
firstVertexis the index of the first vertex to draw. -
firstInstanceis the instance ID of the first instance to draw.
The members of VkDrawIndirectCommand have the same meaning as the
similarly named parameters of vkCmdDraw.
To record a non-indexed draw call with a draw call count sourced from a buffer, call:
void vkCmdDrawIndirectCountKHR(
VkCommandBuffer commandBuffer,
VkBuffer buffer,
VkDeviceSize offset,
VkBuffer countBuffer,
VkDeviceSize countBufferOffset,
uint32_t maxDrawCount,
uint32_t stride);
-
commandBufferis the command buffer into which the command is recorded. -
bufferis the buffer containing draw parameters. -
offsetis the byte offset intobufferwhere parameters begin. -
countBufferis the buffer containing the draw count. -
countBufferOffsetis the byte offset intocountBufferwhere the draw count begins. -
maxDrawCountspecifies the maximum number of draws that will be executed. The actual number of executed draw calls is the minimum of the count specified incountBufferandmaxDrawCount. -
strideis the byte stride between successive sets of draw parameters.
vkCmdDrawIndirectCountKHR behaves similarly to vkCmdDrawIndirect
except that the draw count is read by the device from a buffer during
execution.
The command will read an unsigned 32-bit integer from countBuffer
located at countBufferOffset and use this as the draw count.
To record a non-indexed draw call with a draw call count sourced from a buffer, call:
void vkCmdDrawIndirectCountAMD(
VkCommandBuffer commandBuffer,
VkBuffer buffer,
VkDeviceSize offset,
VkBuffer countBuffer,
VkDeviceSize countBufferOffset,
uint32_t maxDrawCount,
uint32_t stride);
-
commandBufferis the command buffer into which the command is recorded. -
bufferis the buffer containing draw parameters. -
offsetis the byte offset intobufferwhere parameters begin. -
countBufferis the buffer containing the draw count. -
countBufferOffsetis the byte offset intocountBufferwhere the draw count begins. -
maxDrawCountspecifies the maximum number of draws that will be executed. The actual number of executed draw calls is the minimum of the count specified incountBufferandmaxDrawCount. -
strideis the byte stride between successive sets of draw parameters.
vkCmdDrawIndirectCountAMD behaves similarly to vkCmdDrawIndirect
except that the draw count is read by the device from a buffer during
execution.
The command will read an unsigned 32-bit integer from countBuffer
located at countBufferOffset and use this as the draw count.
To record an indexed indirect draw, call:
void vkCmdDrawIndexedIndirect(
VkCommandBuffer commandBuffer,
VkBuffer buffer,
VkDeviceSize offset,
uint32_t drawCount,
uint32_t stride);
-
commandBufferis the command buffer into which the command is recorded. -
bufferis the buffer containing draw parameters. -
offsetis the byte offset intobufferwhere parameters begin. -
drawCountis the number of draws to execute, and can be zero. -
strideis the byte stride between successive sets of draw parameters.
vkCmdDrawIndexedIndirect behaves similarly to vkCmdDrawIndexed
except that the parameters are read by the device from a buffer during
execution.
drawCount draws are executed by the command, with parameters taken
from buffer starting at offset and increasing by stride
bytes for each successive draw.
The parameters of each draw are encoded in an array of
VkDrawIndexedIndirectCommand structures.
If drawCount is less than or equal to one, stride is ignored.
The VkDrawIndexedIndirectCommand structure is defined as:
typedef struct VkDrawIndexedIndirectCommand {
uint32_t indexCount;
uint32_t instanceCount;
uint32_t firstIndex;
int32_t vertexOffset;
uint32_t firstInstance;
} VkDrawIndexedIndirectCommand;
-
indexCountis the number of vertices to draw. -
instanceCountis the number of instances to draw. -
firstIndexis the base index within the index buffer. -
vertexOffsetis the value added to the vertex index before indexing into the vertex buffer. -
firstInstanceis the instance ID of the first instance to draw.
The members of VkDrawIndexedIndirectCommand have the same meaning as
the similarly named parameters of vkCmdDrawIndexed.
To record an indexed draw call with a draw call count sourced from a buffer, call:
void vkCmdDrawIndexedIndirectCountKHR(
VkCommandBuffer commandBuffer,
VkBuffer buffer,
VkDeviceSize offset,
VkBuffer countBuffer,
VkDeviceSize countBufferOffset,
uint32_t maxDrawCount,
uint32_t stride);
-
commandBufferis the command buffer into which the command is recorded. -
bufferis the buffer containing draw parameters. -
offsetis the byte offset intobufferwhere parameters begin. -
countBufferis the buffer containing the draw count. -
countBufferOffsetis the byte offset intocountBufferwhere the draw count begins. -
maxDrawCountspecifies the maximum number of draws that will be executed. The actual number of executed draw calls is the minimum of the count specified incountBufferandmaxDrawCount. -
strideis the byte stride between successive sets of draw parameters.
vkCmdDrawIndexedIndirectCountKHR behaves similarly to
vkCmdDrawIndexedIndirect except that the draw count is read by the
device from a buffer during execution.
The command will read an unsigned 32-bit integer from countBuffer
located at countBufferOffset and use this as the draw count.
To record an indexed draw call with a draw call count sourced from a buffer, call:
void vkCmdDrawIndexedIndirectCountAMD(
VkCommandBuffer commandBuffer,
VkBuffer buffer,
VkDeviceSize offset,
VkBuffer countBuffer,
VkDeviceSize countBufferOffset,
uint32_t maxDrawCount,
uint32_t stride);
-
commandBufferis the command buffer into which the command is recorded. -
bufferis the buffer containing draw parameters. -
offsetis the byte offset intobufferwhere parameters begin. -
countBufferis the buffer containing the draw count. -
countBufferOffsetis the byte offset intocountBufferwhere the draw count begins. -
maxDrawCountspecifies the maximum number of draws that will be executed. The actual number of executed draw calls is the minimum of the count specified incountBufferandmaxDrawCount. -
strideis the byte stride between successive sets of draw parameters.
vkCmdDrawIndexedIndirectCountAMD behaves similarly to
vkCmdDrawIndexedIndirect except that the draw count is read by the
device from a buffer during execution.
The command will read an unsigned 32-bit integer from countBuffer
located at countBufferOffset and use this as the draw count.
20. Fixed-Function Vertex Processing
Vertex fetching is controlled via configurable state, as a logically distinct graphics pipeline stage.
20.1. Vertex Attributes
Vertex shaders can define input variables, which receive vertex attribute
data transferred from one or more VkBuffer(s) by drawing commands.
Vertex shader input variables are bound to buffers via an indirect binding
where the vertex shader associates a vertex input attribute number with
each variable, vertex input attributes are associated to vertex input
bindings on a per-pipeline basis, and vertex input bindings are associated
with specific buffers on a per-draw basis via the
vkCmdBindVertexBuffers command.
Vertex input attribute and vertex input binding descriptions also contain
format information controlling how data is extracted from buffer memory and
converted to the format expected by the vertex shader.
There are VkPhysicalDeviceLimits::maxVertexInputAttributes
number of vertex input attributes and
VkPhysicalDeviceLimits::maxVertexInputBindings number of vertex
input bindings (each referred to by zero-based indices), where there are at
least as many vertex input attributes as there are vertex input bindings.
Applications can store multiple vertex input attributes interleaved in a
single buffer, and use a single vertex input binding to access those
attributes.
In GLSL, vertex shaders associate input variables with a vertex input
attribute number using the location layout qualifier.
The component layout qualifier associates components of a vertex shader
input variable with components of a vertex input attribute.
// Assign location M to variableName
layout (location=M, component=2) in vec2 variableName;
// Assign locations [N,N+L) to the array elements of variableNameArray
layout (location=N) in vec4 variableNameArray[L];
In SPIR-V, vertex shaders associate input variables with a vertex input
attribute number using the Location decoration.
The Component decoration associates components of a vertex shader input
variable with components of a vertex input attribute.
The Location and Component decorations are specified via the
OpDecorate instruction.
...
%1 = OpExtInstImport "GLSL.std.450"
...
OpName %9 "variableName"
OpName %15 "variableNameArray"
OpDecorate %18 BuiltIn VertexIndex
OpDecorate %19 BuiltIn InstanceIndex
OpDecorate %9 Location M
OpDecorate %9 Component 2
OpDecorate %15 Location N
...
%2 = OpTypeVoid
%3 = OpTypeFunction %2
%6 = OpTypeFloat 32
%7 = OpTypeVector %6 2
%8 = OpTypePointer Input %7
%9 = OpVariable %8 Input
%10 = OpTypeVector %6 4
%11 = OpTypeInt 32 0
%12 = OpConstant %11 L
%13 = OpTypeArray %10 %12
%14 = OpTypePointer Input %13
%15 = OpVariable %14 Input
...
20.1.1. Attribute Location and Component Assignment
Vertex shaders allow Location and Component decorations on input
variable declarations.
The Location decoration specifies which vertex input attribute is used
to read and interpret the data that a variable will consume.
The Component decoration allows the location to be more finely
specified for scalars and vectors, down to the individual components within
a location that are consumed.
The components within a location are 0, 1, 2, and 3.
A variable starting at component N will consume components N, N+1, N+2, …
up through its size.
For single precision types, it is invalid if the sequence of components gets
larger than 3.
When a vertex shader input variable declared using a scalar or vector 32-bit
data type is assigned a location, its value(s) are taken from the components
of the input attribute specified with the corresponding
VkVertexInputAttributeDescription::location.
The components used depend on the type of variable and the Component
decoration specified in the variable declaration, as identified in
Input attribute components accessed by 32-bit input variables.
Any 32-bit scalar or vector input will consume a single location.
For 32-bit data types, missing components are filled in with default values
as described below.
| 32-bit data type | Component decoration |
Components consumed |
|---|---|---|
scalar |
0 or unspecified |
(x, o, o, o) |
scalar |
1 |
(o, y, o, o) |
scalar |
2 |
(o, o, z, o) |
scalar |
3 |
(o, o, o, w) |
two-component vector |
0 or unspecified |
(x, y, o, o) |
two-component vector |
1 |
(o, y, z, o) |
two-component vector |
2 |
(o, o, z, w) |
three-component vector |
0 or unspecified |
(x, y, z, o) |
three-component vector |
1 |
(o, y, z, w) |
four-component vector |
0 or unspecified |
(x, y, z, w) |
Components indicated by “o” are available for use by other input variables which are sourced from the same attribute, and if used, are either filled with the corresponding component from the input format (if present), or the default value.
When a vertex shader input variable declared using a 32-bit floating point
matrix type is assigned a location i, its values are taken from
consecutive input attributes starting with the corresponding
VkVertexInputAttributeDescription::location.
Such matrices are treated as an array of column vectors with values taken
from the input attributes identified in Input attributes accessed by 32-bit input matrix variables.
The VkVertexInputAttributeDescription::format must be specified
with a VkFormat that corresponds to the appropriate type of column
vector.
The Component decoration must not be used with matrix types.
| Data type | Column vector type | Locations consumed | Components consumed |
|---|---|---|---|
mat2 |
two-component vector |
i, i+1 |
(x, y, o, o), (x, y, o, o) |
mat2x3 |
three-component vector |
i, i+1 |
(x, y, z, o), (x, y, z, o) |
mat2x4 |
four-component vector |
i, i+1 |
(x, y, z, w), (x, y, z, w) |
mat3x2 |
two-component vector |
i, i+1, i+2 |
(x, y, o, o), (x, y, o, o), (x, y, o, o) |
mat3 |
three-component vector |
i, i+1, i+2 |
(x, y, z, o), (x, y, z, o), (x, y, z, o) |
mat3x4 |
four-component vector |
i, i+1, i+2 |
(x, y, z, w), (x, y, z, w), (x, y, z, w) |
mat4x2 |
two-component vector |
i, i+1, i+2, i+3 |
(x, y, o, o), (x, y, o, o), (x, y, o, o), (x, y, o, o) |
mat4x3 |
three-component vector |
i, i+1, i+2, i+3 |
(x, y, z, o), (x, y, z, o), (x, y, z, o), (x, y, z, o) |
mat4 |
four-component vector |
i, i+1, i+2, i+3 |
(x, y, z, w), (x, y, z, w), (x, y, z, w), (x, y, z, w) |
Components indicated by “o” are available for use by other input variables which are sourced from the same attribute, and if used, are either filled with the corresponding component from the input (if present), or the default value.
When a vertex shader input variable declared using a scalar or vector 64-bit
data type is assigned a location i, its values are taken from consecutive
input attributes starting with the corresponding
VkVertexInputAttributeDescription::location.
The locations and components used depend on the type of variable and the
Component decoration specified in the variable declaration, as
identified in Input attribute locations and components accessed by 64-bit input variables.
For 64-bit data types, no default attribute values are provided.
Input variables must not use more components than provided by the
attribute.
Input attributes which have one- or two-component 64-bit formats will
consume a single location.
Input attributes which have three- or four-component 64-bit formats will
consume two consecutive locations.
A 64-bit scalar data type will consume two components, and a 64-bit
two-component vector data type will consume all four components available
within a location.
A three- or four-component 64-bit data type must not specify a component.
A three-component 64-bit data type will consume all four components of the
first location and components 0 and 1 of the second location.
This leaves components 2 and 3 available for other component-qualified
declarations.
A four-component 64-bit data type will consume all four components of the
first location and all four components of the second location.
It is invalid for a scalar or two-component 64-bit data type to specify a
component of 1 or 3.
| Input format | Locations consumed | 64-bit data type | Location decoration |
Component decoration |
32-bit components consumed |
|---|---|---|---|---|---|
R64 |
i |
scalar |
i |
0 or unspecified |
(x, y, -, -) |
R64G64 |
i |
scalar |
i |
0 or unspecified |
(x, y, o, o) |
scalar |
i |
2 |
(o, o, z, w) |
||
two-component vector |
i |
0 or unspecified |
(x, y, z, w) |
||
R64G64B64 |
i, i+1 |
scalar |
i |
0 or unspecified |
(x, y, o, o), (o, o, -, -) |
scalar |
i |
2 |
(o, o, z, w), (o, o, -, -) |
||
scalar |
i+1 |
0 or unspecified |
(o, o, o, o), (x, y, -, -) |
||
two-component vector |
i |
0 or unspecified |
(x, y, z, w), (o, o, -, -) |
||
three-component vector |
i |
unspecified |
(x, y, z, w), (x, y, -, -) |
||
R64G64B64A64 |
i, i+1 |
scalar |
i |
0 or unspecified |
(x, y, o, o), (o, o, o, o) |
scalar |
i |
2 |
(o, o, z, w), (o, o, o, o) |
||
scalar |
i+1 |
0 or unspecified |
(o, o, o, o), (x, y, o, o) |
||
scalar |
i+1 |
2 |
(o, o, o, o), (o, o, z, w) |
||
two-component vector |
i |
0 or unspecified |
(x, y, z, w), (o, o, o, o) |
||
two-component vector |
i+1 |
0 or unspecified |
(o, o, o, o), (x, y, z, w) |
||
three-component vector |
i |
unspecified |
(x, y, z, w), (x, y, o, o) |
||
four-component vector |
i |
unspecified |
(x, y, z, w), (x, y, z, w) |
Components indicated by “o” are available for use by other input variables which are sourced from the same attribute. Components indicated by “-” are not available for input variables as there are no default values provided for 64-bit data types, and there is no data provided by the input format.
When a vertex shader input variable declared using a 64-bit floating-point matrix type is assigned a location i, its values are taken from consecutive input attribute locations. Such matrices are treated as an array of column vectors with values taken from the input attributes as shown in Input attribute locations and components accessed by 64-bit input variables. Each column vector starts at the location immediately following the last location of the previous column vector. The number of attributes and components assigned to each matrix is determined by the matrix dimensions and ranges from two to eight locations.
When a vertex shader input variable declared using an array type is assigned
a location, its values are taken from consecutive input attributes starting
with the corresponding
VkVertexInputAttributeDescription::location.
The number of attributes and components assigned to each element are
determined according to the data type of the array elements and
Component decoration (if any) specified in the declaration of the
array, as described above.
Each element of the array, in order, is assigned to consecutive locations,
but all at the same specified component within each location.
Only input variables declared with the data types and component decorations as specified above are supported. Location aliasing is causing two variables to have the same location number. Component aliasing is assigning the same (or overlapping) component number for two location aliases. Location aliasing is allowed only if it does not cause component aliasing. Further, when location aliasing, the aliases sharing the location must all have the same SPIR-V floating-point component type or all have the same width integer-type components.
20.2. Vertex Input Description
Applications specify vertex input attribute and vertex input binding
descriptions as part of graphics pipeline creation.
The VkGraphicsPipelineCreateInfo::pVertexInputState points to a
structure of type VkPipelineVertexInputStateCreateInfo.
The VkPipelineVertexInputStateCreateInfo structure is defined as:
typedef struct VkPipelineVertexInputStateCreateInfo {
VkStructureType sType;
const void* pNext;
VkPipelineVertexInputStateCreateFlags flags;
uint32_t vertexBindingDescriptionCount;
const VkVertexInputBindingDescription* pVertexBindingDescriptions;
uint32_t vertexAttributeDescriptionCount;
const VkVertexInputAttributeDescription* pVertexAttributeDescriptions;
} VkPipelineVertexInputStateCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
vertexBindingDescriptionCountis the number of vertex binding descriptions provided inpVertexBindingDescriptions. -
pVertexBindingDescriptionsis a pointer to an array ofVkVertexInputBindingDescriptionstructures. -
vertexAttributeDescriptionCountis the number of vertex attribute descriptions provided inpVertexAttributeDescriptions. -
pVertexAttributeDescriptionsis a pointer to an array ofVkVertexInputAttributeDescriptionstructures.
typedef VkFlags VkPipelineVertexInputStateCreateFlags;
VkPipelineVertexInputStateCreateFlags is a bitmask type for setting a
mask, but is currently reserved for future use.
Each vertex input binding is specified by an instance of the
VkVertexInputBindingDescription structure.
The VkVertexInputBindingDescription structure is defined as:
typedef struct VkVertexInputBindingDescription {
uint32_t binding;
uint32_t stride;
VkVertexInputRate inputRate;
} VkVertexInputBindingDescription;
-
bindingis the binding number that this structure describes. -
strideis the distance in bytes between two consecutive elements within the buffer. -
inputRateis a VkVertexInputRate value specifying whether vertex attribute addressing is a function of the vertex index or of the instance index.
Possible values of VkVertexInputBindingDescription::inputRate,
specifying the rate at which vertex attributes are pulled from buffers, are:
typedef enum VkVertexInputRate {
VK_VERTEX_INPUT_RATE_VERTEX = 0,
VK_VERTEX_INPUT_RATE_INSTANCE = 1,
} VkVertexInputRate;
-
VK_VERTEX_INPUT_RATE_VERTEXspecifies that vertex attribute addressing is a function of the vertex index. -
VK_VERTEX_INPUT_RATE_INSTANCEspecifies that vertex attribute addressing is a function of the instance index.
Each vertex input attribute is specified by an instance of the
VkVertexInputAttributeDescription structure.
The VkVertexInputAttributeDescription structure is defined as:
typedef struct VkVertexInputAttributeDescription {
uint32_t location;
uint32_t binding;
VkFormat format;
uint32_t offset;
} VkVertexInputAttributeDescription;
-
locationis the shader binding location number for this attribute. -
bindingis the binding number which this attribute takes its data from. -
formatis the size and type of the vertex attribute data. -
offsetis a byte offset of this attribute relative to the start of an element in the vertex input binding.
To bind vertex buffers to a command buffer for use in subsequent draw commands, call:
void vkCmdBindVertexBuffers(
VkCommandBuffer commandBuffer,
uint32_t firstBinding,
uint32_t bindingCount,
const VkBuffer* pBuffers,
const VkDeviceSize* pOffsets);
-
commandBufferis the command buffer into which the command is recorded. -
firstBindingis the index of the first vertex input binding whose state is updated by the command. -
bindingCountis the number of vertex input bindings whose state is updated by the command. -
pBuffersis a pointer to an array of buffer handles. -
pOffsetsis a pointer to an array of buffer offsets.
The values taken from elements i of pBuffers and pOffsets
replace the current state for the vertex input binding
firstBinding + i, for i in [0,
bindingCount).
The vertex input binding is updated to start at the offset indicated by
pOffsets[i] from the start of the buffer pBuffers[i].
All vertex input attributes that use each of these bindings will use these
updated addresses in their address calculations for subsequent draw
commands.
20.3. Vertex Attribute Divisor in Instanced Rendering
If the pNext chain of VkPipelineVertexInputStateCreateInfo
includes a VkPipelineVertexInputDivisorStateCreateInfoEXT structure,
then that structure controls how vertex attributes are assigned to an
instance when instanced rendering is enabled.
The VkPipelineVertexInputDivisorStateCreateInfoEXT structure is
defined as:
typedef struct VkPipelineVertexInputDivisorStateCreateInfoEXT {
VkStructureType sType;
const void* pNext;
uint32_t vertexBindingDivisorCount;
const VkVertexInputBindingDivisorDescriptionEXT* pVertexBindingDivisors;
} VkPipelineVertexInputDivisorStateCreateInfoEXT;
-
sTypeis the type of this structure -
pNextisNULLor a pointer to an extension-specific structure -
vertexBindingDivisorCountis the number of elements in thepVertexBindingDivisorsarray. -
pVertexBindingDivisorsis a pointer to an array ofVkVertexInputBindingDivisorDescriptionEXTstructures, which specifies the divisor value for each binding.
The individual divisor values per binding are specified using the
VkVertexInputBindingDivisorDescriptionEXT structure which is defined
as:
typedef struct VkVertexInputBindingDivisorDescriptionEXT {
uint32_t binding;
uint32_t divisor;
} VkVertexInputBindingDivisorDescriptionEXT;
-
bindingis the binding number for which the divisor is specified. -
divisoris the the number of successive instances that will use the same value of the vertex attribute when instanced rendering is enabled. For example, if the divisor is N, the same vertex attribute will applied to N successive instances before moving on to the next vertex attribute. If a value of 0 is used for the divisor, then the first vertex attribute will be applied to all instances. The maximum value of divisor is implementation dependent and can be queried usingVkPhysicalDeviceVertexAttributeDivisorPropertiesEXT::maxVertexAttribDivisor.
If this structure is not used to define a divisor value for an attribute then the divisor has a logical default value of 1.
The address of each attribute for each vertexIndex and
instanceIndex is calculated as follows:
-
Let
attribDescbe the member ofVkPipelineVertexInputStateCreateInfo::pVertexAttributeDescriptionswithVkVertexInputAttributeDescription::locationequal to the vertex input attribute number. -
Let
bindingDescbe the member ofVkPipelineVertexInputStateCreateInfo::pVertexBindingDescriptionswithVkVertexInputAttributeDescription::bindingequal toattribDesc.binding. -
Let
vertexIndexbe the index of the vertex within the draw (a value betweenfirstVertexandfirstVertex+vertexCountforvkCmdDraw, or a value taken from the index buffer forvkCmdDrawIndexed), and letinstanceIndexbe the instance number of the draw (a value betweenfirstInstanceandfirstInstance+instanceCount). -
Let
divisorbe the member ofVkPipelineVertexInputDivisorStateCreateInfoEXT::pVertexBindingDivisorswithVkVertexInputBindingDivisorDescriptionEXT::bindingequal toattribDesc.binding.
bufferBindingAddress = buffer[binding].baseAddress + offset[binding];
if (bindingDesc.inputRate == VK_VERTEX_INPUT_RATE_VERTEX)
vertexOffset = vertexIndex * bindingDesc.stride;
else
if (divisor == 0)
vertexOffset = 0;
else
vertexOffset = (instanceIndex / divisor) * bindingDesc.stride;
attribAddress = bufferBindingAddress + vertexOffset + attribDesc.offset;
For each attribute, raw data is extracted starting at attribAddress and is
converted from the VkVertexInputAttributeDescription’s format to
either to floating-point, unsigned integer, or signed integer based on the
base type of the format; the base type of the format must match the base
type of the input variable in the shader.
If format is a packed format, attribAddress must be a multiple of
the size in bytes of the whole attribute data type as described in
Packed Formats.
Otherwise, attribAddress must be a multiple of the size in bytes of the
component type indicated by format (see Formats).
If the format does not include G, B, or A components, then those are filled
with (0,0,1) as needed (using either 1.0f or integer 1 based on the
format) for attributes that are not 64-bit data types.
The number of components in the vertex shader input variable need not
exactly match the number of components in the format.
If the vertex shader has fewer components, the extra components are
discarded.
20.4. Example
To create a graphics pipeline that uses the following vertex description:
struct Vertex
{
float x, y, z, w;
uint8_t u, v;
};
The application could use the following set of structures:
const VkVertexInputBindingDescription binding =
{
0, // binding
sizeof(Vertex), // stride
VK_VERTEX_INPUT_RATE_VERTEX // inputRate
};
const VkVertexInputAttributeDescription attributes[] =
{
{
0, // location
binding.binding, // binding
VK_FORMAT_R32G32B32A32_SFLOAT, // format
0 // offset
},
{
1, // location
binding.binding, // binding
VK_FORMAT_R8G8_UNORM, // format
4 * sizeof(float) // offset
}
};
const VkPipelineVertexInputStateCreateInfo viInfo =
{
VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_CREATE_INFO, // sType
NULL, // pNext
0, // flags
1, // vertexBindingDescriptionCount
&binding, // pVertexBindingDescriptions
2, // vertexAttributeDescriptionCount
&attributes[0] // pVertexAttributeDescriptions
};
21. Tessellation
Tessellation involves three pipeline stages. First, a tessellation control shader transforms control points of a patch and can produce per-patch data. Second, a fixed-function tessellator generates multiple primitives corresponding to a tessellation of the patch in (u,v) or (u,v,w) parameter space. Third, a tessellation evaluation shader transforms the vertices of the tessellated patch, for example to compute their positions and attributes as part of the tessellated surface. The tessellator is enabled when the pipeline contains both a tessellation control shader and a tessellation evaluation shader.
21.1. Tessellator
If a pipeline includes both tessellation shaders (control and evaluation),
the tessellator consumes each input patch (after vertex shading) and
produces a new set of independent primitives (points, lines, or triangles).
These primitives are logically produced by subdividing a geometric primitive
(rectangle or triangle) according to the per-patch outer and inner
tessellation levels written by the tessellation control shader.
These levels are specified using the built-in
variables TessLevelOuter and TessLevelInner, respectively.
This subdivision is performed in an implementation-dependent manner.
If no tessellation shaders are present in the pipeline, the tessellator is
disabled and incoming primitives are passed through without modification.
The type of subdivision performed by the tessellator is specified by an
OpExecutionMode instruction in the tessellation evaluation or
tessellation control shader using one of execution modes Triangles,
Quads, and IsoLines.
Other tessellation-related execution modes can also be specified in either
the tessellation control or tessellation evaluation shaders, and if they are
specified in both then the modes must be the same.
Tessellation execution modes include:
-
Triangles,Quads, andIsoLines. These control the type of subdivision and topology of the output primitives. One mode must be set in at least one of the tessellation shader stages. -
VertexOrderCwandVertexOrderCcw. These control the orientation of triangles generated by the tessellator. One mode must be set in at least one of the tessellation shader stages. -
PointMode. Controls generation of points rather than triangles or lines. This functionality defaults to disabled, and is enabled if either shader stage includes the execution mode. -
SpacingEqual,SpacingFractionalEven, andSpacingFractionalOdd. Controls the spacing of segments on the edges of tessellated primitives. One mode must be set in at least one of the tessellation shader stages. -
OutputVertices. Controls the size of the output patch of the tessellation control shader. One value must be set in at least one of the tessellation shader stages.
For triangles, the tessellator subdivides a triangle primitive into smaller
triangles.
For quads, the tessellator subdivides a rectangle primitive into smaller
triangles.
For isolines, the tessellator subdivides a rectangle primitive into a
collection of line segments arranged in strips stretching across the
rectangle in the u dimension (i.e. the coordinates in TessCoord
are of the form (0,x) through (1,x) for all tessellation evaluation shader
invocations that share a line).
Each vertex produced by the tessellator has an associated (u,v,w) or (u,v)
position in a normalized parameter space, with parameter values in the range
[0,1], as illustrated
in figures Domain parameterization for tessellation primitive modes (upper-left origin) and
Domain parameterization for tessellation primitive modes (lower-left origin).
The domain space can have either an upper-left or lower-left origin,
selected by the domainOrigin member of
VkPipelineTessellationDomainOriginStateCreateInfo.
For triangles, the vertex’s position is a barycentric coordinate (u,v,w), where u + v + w = 1.0, and indicates the relative influence of the three vertices of the triangle on the position of the vertex. For quads and isolines, the position is a (u,v) coordinate indicating the relative horizontal and vertical position of the vertex relative to the subdivided rectangle. The subdivision process is explained in more detail in subsequent sections.
21.2. Tessellator Patch Discard
A patch is discarded by the tessellator if any relevant outer tessellation level is less than or equal to zero.
Patches will also be discarded if any relevant outer tessellation level corresponds to a floating-point NaN (not a number) in implementations supporting NaN.
No new primitives are generated and the tessellation evaluation shader is
not executed for patches that are discarded.
For Quads, all four outer levels are relevant.
For Triangles and IsoLines, only the first three or two outer
levels, respectively, are relevant.
Negative inner levels will not cause a patch to be discarded; they will be
clamped as described below.
21.3. Tessellator Spacing
Each of the tessellation levels is used to determine the number and spacing
of segments used to subdivide a corresponding edge.
The method used to derive the number and spacing of segments is specified by
an OpExecutionMode in the tessellation control or tessellation
evaluation shader using one of the identifiers SpacingEqual,
SpacingFractionalEven, or SpacingFractionalOdd.
If SpacingEqual is used, the floating-point tessellation level is first
clamped to [1, maxLevel], where maxLevel is the
implementation-dependent maximum tessellation level
(VkPhysicalDeviceLimits::maxTessellationGenerationLevel).
The result is rounded up to the nearest integer n, and the
corresponding edge is divided into n segments of equal length in (u,v)
space.
If SpacingFractionalEven is used, the tessellation level is first
clamped to [2, maxLevel] and then rounded up to the nearest even
integer n.
If SpacingFractionalOdd is used, the tessellation level is clamped to
[1, maxLevel - 1] and then rounded up to the nearest odd integer
n.
If n is one, the edge will not be subdivided.
Otherwise, the corresponding edge will be divided into n - 2 segments
of equal length, and two additional segments of equal length that are
typically shorter than the other segments.
The length of the two additional segments relative to the others will
decrease monotonically with n - f, where f is the clamped
floating-point tessellation level.
When n - f is zero, the additional segments will have equal length to
the other segments.
As n - f approaches 2.0, the relative length of the additional
segments approaches zero.
The two additional segments must be placed symmetrically on opposite sides
of the subdivided edge.
The relative location of these two segments is implementation-dependent, but
must be identical for any pair of subdivided edges with identical values of
f.
When the tessellator produces triangles (in the Triangles or Quads
modes), the orientation of all triangles is specified with an
OpExecutionMode of VertexOrderCw or VertexOrderCcw in the
tessellation control or tessellation evaluation shaders.
If the order is VertexOrderCw, the vertices of all generated triangles
will have clockwise ordering in (u,v) or (u,v,w) space.
If the order is VertexOrderCcw, the vertices will have
counter-clockwise ordering.
If the tessellation domain has an upper-left origin, the vertices of a triangle have counter-clockwise ordering if
-
a = u0 v1 - u1 v0 + u1 v2 - u2 v1 + u2 v0 - u0 v2
is negative, and clockwise ordering if a is positive. ui and vi are the u and v coordinates in normalized parameter space of the ith vertex of the triangle. If the tessellation domain has a lower-left origin, the vertices of a triangle have counter-clockwise ordering if a is positive, and clockwise ordering if a is negative.
|
Note
The value a is proportional (with a positive factor) to the signed area of the triangle. In |
For all primitive modes, the tessellator is capable of generating points
instead of lines or triangles.
If the tessellation control or tessellation evaluation shader specifies the
OpExecutionMode PointMode, the primitive generator will generate
one point for each distinct vertex produced by tessellation.
Otherwise, the tessellator will produce a collection of line segments or
triangles according to the primitive mode.
When tessellating triangles or quads in point mode with fractional odd
spacing, the tessellator may produce interior vertices that are
positioned on the edge of the patch if an inner tessellation level is less
than or equal to one.
Such vertices are considered distinct from vertices produced by subdividing
the outer edge of the patch, even if there are pairs of vertices with
identical coordinates.
21.4. Tessellation Primitive Ordering
Few guarantees are provided for the relative ordering of primitives produced by tessellation, as they pertain to primitive order.
-
The output primitives generated from each input primitive are passed to subsequent pipeline stages in an implementation-dependent order.
-
All output primitives generated from a given input primitive are passed to subsequent pipeline stages before any output primitives generated from subsequent input primitives.
21.5. Triangle Tessellation
If the tessellation primitive mode is Triangles, an equilateral
triangle is subdivided into a collection of triangles covering the area of
the original triangle.
First, the original triangle is subdivided into a collection of concentric
equilateral triangles.
The edges of each of these triangles are subdivided, and the area between
each triangle pair is filled by triangles produced by joining the vertices
on the subdivided edges.
The number of concentric triangles and the number of subdivisions along each
triangle except the outermost is derived from the first inner tessellation
level.
The edges of the outermost triangle are subdivided independently, using the
first, second, and third outer tessellation levels to control the number of
subdivisions of the u = 0 (left), v = 0 (bottom), and w =
0 (right) edges, respectively.
The second inner tessellation level and the fourth outer tessellation level
have no effect in this mode.
If the first inner tessellation level and all three outer tessellation levels are exactly one after clamping and rounding, only a single triangle with (u,v,w) coordinates of (0,0,1), (1,0,0), and (0,1,0) is generated. If the inner tessellation level is one and any of the outer tessellation levels is greater than one, the inner tessellation level is treated as though it were originally specified as 1 + ε and will result in a two- or three-segment subdivision depending on the tessellation spacing. When used with fractional odd spacing, the three-segment subdivision may produce inner vertices positioned on the edge of the triangle.
If any tessellation level is greater than one, tessellation begins by producing a set of concentric inner triangles and subdividing their edges. First, the three outer edges are temporarily subdivided using the clamped and rounded first inner tessellation level and the specified tessellation spacing, generating n segments. For the outermost inner triangle, the inner triangle is degenerate — a single point at the center of the triangle — if n is two. Otherwise, for each corner of the outer triangle, an inner triangle corner is produced at the intersection of two lines extended perpendicular to the corner’s two adjacent edges running through the vertex of the subdivided outer edge nearest that corner. If n is three, the edges of the inner triangle are not subdivided and is the final triangle in the set of concentric triangles. Otherwise, each edge of the inner triangle is divided into n - 2 segments, with the n - 1 vertices of this subdivision produced by intersecting the inner edge with lines perpendicular to the edge running through the n - 1 innermost vertices of the subdivision of the outer edge. Once the outermost inner triangle is subdivided, the previous subdivision process repeats itself, using the generated triangle as an outer triangle. This subdivision process is illustrated in Inner Triangle Tessellation.
Once all the concentric triangles are produced and their edges are subdivided, the area between each pair of adjacent inner triangles is filled completely with a set of non-overlapping triangles. In this subdivision, two of the three vertices of each triangle are taken from adjacent vertices on a subdivided edge of one triangle; the third is one of the vertices on the corresponding edge of the other triangle. If the innermost triangle is degenerate (i.e., a point), the triangle containing it is subdivided into six triangles by connecting each of the six vertices on that triangle with the center point. If the innermost triangle is not degenerate, that triangle is added to the set of generated triangles as-is.
After the area corresponding to any inner triangles is filled, the tessellator generates triangles to cover the area between the outermost triangle and the outermost inner triangle. To do this, the temporary subdivision of the outer triangle edge above is discarded. Instead, the u = 0, v = 0, and w = 0 edges are subdivided according to the first, second, and third outer tessellation levels, respectively, and the tessellation spacing. The original subdivision of the first inner triangle is retained. The area between the outer and first inner triangles is completely filled by non-overlapping triangles as described above. If the first (and only) inner triangle is degenerate, a set of triangles is produced by connecting each vertex on the outer triangle edges with the center point.
After all triangles are generated, each vertex in the subdivided triangle is assigned a barycentric (u,v,w) coordinate based on its location relative to the three vertices of the outer triangle.
The algorithm used to subdivide the triangular domain in (u,v,w) space into individual triangles is implementation-dependent. However, the set of triangles produced will completely cover the domain, and no portion of the domain will be covered by multiple triangles.
The order in which the vertices for a given output triangle is generated is implementation-dependent. However, when depicted in a manner similar to Inner Triangle Tessellation, the order of the vertices in each generated triangle will be either all clockwise or all counter-clockwise, according to the vertex order layout declaration.
21.6. Quad Tessellation
If the tessellation primitive mode is Quads, a rectangle is subdivided
into a collection of triangles covering the area of the original rectangle.
First, the original rectangle is subdivided into a regular mesh of
rectangles, where the number of rectangles along the u = 0 and u
= 1 (vertical) and v = 0 and v = 1 (horizontal) edges are
derived from the first and second inner tessellation levels, respectively.
All rectangles, except those adjacent to one of the outer rectangle edges,
are decomposed into triangle pairs.
The outermost rectangle edges are subdivided independently, using the first,
second, third, and fourth outer tessellation levels to control the number of
subdivisions of the u = 0 (left), v = 0 (bottom), u = 1
(right), and v = 1 (top) edges, respectively.
The area between the inner rectangles of the mesh and the outer rectangle
edges are filled by triangles produced by joining the vertices on the
subdivided outer edges to the vertices on the edge of the inner rectangle
mesh.
If both clamped inner tessellation levels and all four clamped outer tessellation levels are exactly one, only a single triangle pair covering the outer rectangle is generated. Otherwise, if either clamped inner tessellation level is one, that tessellation level is treated as though it were originally specified as 1 + ε and will result in a two- or three-segment subdivision depending on the tessellation spacing. When used with fractional odd spacing, the three-segment subdivision may produce inner vertices positioned on the edge of the rectangle.
If any tessellation level is greater than one, tessellation begins by subdividing the u = 0 and u = 1 edges of the outer rectangle into m segments using the clamped and rounded first inner tessellation level and the tessellation spacing. The v = 0 and v = 1 edges are subdivided into n segments using the second inner tessellation level. Each vertex on the u = 0 and v = 0 edges are joined with the corresponding vertex on the u = 1 and v = 1 edges to produce a set of vertical and horizontal lines that divide the rectangle into a grid of smaller rectangles. The primitive generator emits a pair of non-overlapping triangles covering each such rectangle not adjacent to an edge of the outer rectangle. The boundary of the region covered by these triangles forms an inner rectangle, the edges of which are subdivided by the grid vertices that lie on the edge. If either m or n is two, the inner rectangle is degenerate, and one or both of the rectangle’s edges consist of a single point. This subdivision is illustrated in Figure Inner Quad Tessellation.
After the area corresponding to the inner rectangle is filled, the tessellator must produce triangles to cover the area between the inner and outer rectangles. To do this, the subdivision of the outer rectangle edge above is discarded. Instead, the u = 0, v = 0, u = 1, and v = 1 edges are subdivided according to the first, second, third, and fourth outer tessellation levels, respectively, and the tessellation spacing. The original subdivision of the inner rectangle is retained. The area between the outer and inner rectangles is completely filled by non-overlapping triangles. Two of the three vertices of each triangle are adjacent vertices on a subdivided edge of one rectangle; the third is one of the vertices on the corresponding edge of the other triangle. If either edge of the innermost rectangle is degenerate, the area near the corresponding outer edges is filled by connecting each vertex on the outer edge with the single vertex making up the inner edge.
The algorithm used to subdivide the rectangular domain in (u,v) space into individual triangles is implementation-dependent. However, the set of triangles produced will completely cover the domain, and no portion of the domain will be covered by multiple triangles.
The order in which the vertices for a given output triangle is generated is implementation-dependent. However, when depicted in a manner similar to Inner Quad Tessellation, the order of the vertices in each generated triangle will be either all clockwise or all counter-clockwise, according to the vertex order layout declaration.
21.7. Isoline Tessellation
If the tessellation primitive mode is IsoLines, a set of independent
horizontal line segments is drawn.
The segments are arranged into connected strips called isolines, where the
vertices of each isoline have a constant v coordinate and u coordinates
covering the full range [0,1].
The number of isolines generated is derived from the first outer
tessellation level; the number of segments in each isoline is derived from
the second outer tessellation level.
Both inner tessellation levels and the third and fourth outer tessellation
levels have no effect in this mode.
As with quad tessellation above, isoline tessellation begins with a rectangle. The u = 0 and u = 1 edges of the rectangle are subdivided according to the first outer tessellation level. For the purposes of this subdivision, the tessellation spacing mode is ignored and treated as equal_spacing. An isoline is drawn connecting each vertex on the u = 0 rectangle edge to the corresponding vertex on the u = 1 rectangle edge, except that no line is drawn between (0,1) and (1,1). If the number of isolines on the subdivided u = 0 and u = 1 edges is n, this process will result in n equally spaced lines with constant v coordinates of 0, \(\frac{1}{n}, \frac{2}{n}, \ldots, \frac{n-1}{n}\).
Each of the n isolines is then subdivided according to the second outer tessellation level and the tessellation spacing, resulting in m line segments. Each segment of each line is emitted by the tessellator.
The order in which the vertices for a given output line is generated is implementation-dependent.
21.8. Tessellation Pipeline State
The pTessellationState member of VkGraphicsPipelineCreateInfo
points to a structure of type VkPipelineTessellationStateCreateInfo.
The VkPipelineTessellationStateCreateInfo structure is defined as:
typedef struct VkPipelineTessellationStateCreateInfo {
VkStructureType sType;
const void* pNext;
VkPipelineTessellationStateCreateFlags flags;
uint32_t patchControlPoints;
} VkPipelineTessellationStateCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
patchControlPointsnumber of control points per patch.
typedef VkFlags VkPipelineTessellationStateCreateFlags;
VkPipelineTessellationStateCreateFlags is a bitmask type for setting a
mask, but is currently reserved for future use.
The VkPipelineTessellationDomainOriginStateCreateInfo structure is
defined as:
typedef struct VkPipelineTessellationDomainOriginStateCreateInfo {
VkStructureType sType;
const void* pNext;
VkTessellationDomainOrigin domainOrigin;
} VkPipelineTessellationDomainOriginStateCreateInfo;
or the equivalent
typedef VkPipelineTessellationDomainOriginStateCreateInfo VkPipelineTessellationDomainOriginStateCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
domainOrigincontrols the origin of the tessellation domain space, and is of type VkTessellationDomainOrigin.
If the VkPipelineTessellationDomainOriginStateCreateInfo structure is
included in the pNext chain of
VkPipelineTessellationStateCreateInfo, it controls the origin of the
tessellation domain.
If this structure is not present, it is as if domainOrigin were
VK_TESSELLATION_DOMAIN_ORIGIN_UPPER_LEFT.
The possible tessellation domain origins are specified by the VkTessellationDomainOrigin enumeration:
typedef enum VkTessellationDomainOrigin {
VK_TESSELLATION_DOMAIN_ORIGIN_UPPER_LEFT = 0,
VK_TESSELLATION_DOMAIN_ORIGIN_LOWER_LEFT = 1,
VK_TESSELLATION_DOMAIN_ORIGIN_UPPER_LEFT_KHR = VK_TESSELLATION_DOMAIN_ORIGIN_UPPER_LEFT,
VK_TESSELLATION_DOMAIN_ORIGIN_LOWER_LEFT_KHR = VK_TESSELLATION_DOMAIN_ORIGIN_LOWER_LEFT,
} VkTessellationDomainOrigin;
or the equivalent
typedef VkTessellationDomainOrigin VkTessellationDomainOriginKHR;
-
VK_TESSELLATION_DOMAIN_ORIGIN_UPPER_LEFTspecifies that the origin of the domain space is in the upper left corner, as shown in figure Domain parameterization for tessellation primitive modes (upper-left origin). -
VK_TESSELLATION_DOMAIN_ORIGIN_LOWER_LEFTspecifies that the origin of the domain space is in the lower left corner, as shown in figure Domain parameterization for tessellation primitive modes (lower-left origin).
This enum affects how the VertexOrderCw and VertexOrderCcw
tessellation execution modes are interpreted, since the winding is defined
relative to the orientation of the domain.
22. Geometry Shading
The geometry shader operates on a group of vertices and their associated data assembled from a single input primitive, and emits zero or more output primitives and the group of vertices and their associated data required for each output primitive. Geometry shading is enabled when a geometry shader is included in the pipeline.
22.1. Geometry Shader Input Primitives
Each geometry shader invocation has access to all vertices in the primitive
(and their associated data), which are presented to the shader as an array
of inputs.
The input primitive type expected by the geometry shader is specified with
an OpExecutionMode instruction in the geometry shader, and must be
compatible with the primitive topology used by primitive assembly (if
tessellation is not in use) or must match the type of primitive generated
by the tessellation primitive generator (if tessellation is in use).
Compatibility is defined below, with each input primitive type.
The input primitive types accepted by a geometry shader are:
- Points
-
Geometry shaders that operate on points use an
OpExecutionModeinstruction specifying theInputPointsinput mode. Such a shader is valid only when the pipeline primitive topology isVK_PRIMITIVE_TOPOLOGY_POINT_LIST(if tessellation is not in use) or if tessellation is in use and the tessellation evaluation shader usesPointMode. There is only a single input vertex available for each geometry shader invocation. However, inputs to the geometry shader are still presented as an array, but this array has a length of one. - Lines
-
Geometry shaders that operate on line segments are generated by including an
OpExecutionModeinstruction with theInputLinesmode. Such a shader is valid only for theVK_PRIMITIVE_TOPOLOGY_LINE_LIST, andVK_PRIMITIVE_TOPOLOGY_LINE_STRIPprimitive topologies (if tessellation is not in use) or if tessellation is in use and the tessellation mode isIsolines. There are two input vertices available for each geometry shader invocation. The first vertex refers to the vertex at the beginning of the line segment and the second vertex refers to the vertex at the end of the line segment. - Lines with Adjacency
-
Geometry shaders that operate on line segments with adjacent vertices are generated by including an
OpExecutionModeinstruction with theInputLinesAdjacencymode. Such a shader is valid only for theVK_PRIMITIVE_TOPOLOGY_LINES_WITH_ADJACENCYandVK_PRIMITIVE_TOPOLOGY_LINE_STRIP_WITH_ADJACENCYprimitive topologies and must not be used when tessellation is in use.In this mode, there are four vertices available for each geometry shader invocation. The second vertex refers to attributes of the vertex at the beginning of the line segment and the third vertex refers to the vertex at the end of the line segment. The first and fourth vertices refer to the vertices adjacent to the beginning and end of the line segment, respectively.
- Triangles
-
Geometry shaders that operate on triangles are created by including an
OpExecutionModeinstruction with theTrianglesmode. Such a shader is valid when the pipeline topology isVK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST,VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP, orVK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN(if tessellation is not in use) or when tessellation is in use and the tessellation mode isTrianglesorQuads.In this mode, there are three vertices available for each geometry shader invocation. The first, second, and third vertices refer to attributes of the first, second, and third vertex of the triangle, respectively.
- Triangles with Adjacency
-
Geometry shaders that operate on triangles with adjacent vertices are created by including an
OpExecutionModeinstruction with theInputTrianglesAdjacencymode. Such a shader is valid when the pipeline topology isVK_PRIMITIVE_TOPOLOGY_TRIANGLES_WITH_ADJACENCYorVK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP_WITH_ADJACENCY, and must not be used when tessellation is in use.In this mode, there are six vertices available for each geometry shader invocation. The first, third and fifth vertices refer to attributes of the first, second and third vertex of the triangle, respectively. The second, fourth and sixth vertices refer to attributes of the vertices adjacent to the edges from the first to the second vertex, from the second to the third vertex, and from the third to the first vertex, respectively.
22.2. Geometry Shader Output Primitives
A geometry shader generates primitives in one of three output modes: points,
line strips, or triangle strips.
The primitive mode is specified in the shader using an OpExecutionMode
instruction with the OutputPoints, OutputLineStrip or
OutputTriangleStrip modes, respectively.
Each geometry shader must include exactly one output primitive mode.
The vertices output by the geometry shader are assembled into points, lines, or triangles based on the output primitive type and the resulting primitives are then further processed as described in Rasterization. If the number of vertices emitted by the geometry shader is not sufficient to produce a single primitive, vertices corresponding to incomplete primitives are not processed by subsequent pipeline stages. The number of vertices output by the geometry shader is limited to a maximum count specified in the shader.
The maximum output vertex count is specified in the shader using an
OpExecutionMode instruction with the mode set to OutputVertices
and the maximum number of vertices that will be produced by the geometry
shader specified as a literal.
Each geometry shader must specify a maximum output vertex count.
22.3. Multiple Invocations of Geometry Shaders
Geometry shaders can be invoked more than one time for each input
primitive.
This is known as geometry shader instancing and is requested by including
an OpExecutionMode instruction with mode specified as
Invocations and the number of invocations specified as an integer
literal.
In this mode, the geometry shader will execute n times for each input
primitive, where n is the number of invocations specified in the
OpExecutionMode instruction.
The instance number is available to each invocation as a built-in input
using InvocationId.
22.4. Geometry Shader Primitive Ordering
Limited guarantees are provided for the relative ordering of primitives produced by a geometry shader, as they pertain to primitive order.
-
For instanced geometry shaders, the output primitives generated from each input primitive are passed to subsequent pipeline stages using the invocation number to order the primitives, from least to greatest.
-
All output primitives generated from a given input primitive are passed to subsequent pipeline stages before any output primitives generated from subsequent input primitives.
22.5. Geometry Shader Passthrough
A geometry shader that uses the PassthroughNV decoration on a variable
in its input interface is considered a passthrough geometry shader.
Output primitives in a passthrough geometry shader must have the same
topology as the input primitive and are not produced by emitting vertices.
The vertices of the output primitive have two different types of attributes,
per-vertex and per-primitive.
Geometry shader input variables with PassthroughNV decoration are
considered to produce per-vertex outputs, where values for each output
vertex are copied from the corresponding input vertex.
Any built-in or user-defined geometry shader outputs are considered
per-primitive in a passthrough geometry shader, where a single output value
is copied to all output vertices.
The remainder of this section details the usage of the PassthroughNV
decoration and modifications to the interface matching rules when using
passthrough geometry shaders.
22.5.1. PassthroughNV Decoration
Decorating a geometry shader input variable with the PassthroughNV
decoration indicates that values of this input are copied through to the
corresponding vertex of the output primitive.
Input variables and block members which do not have the PassthroughNV
decoration are consumed by the geometry shader without being passed through
to subsequent stages.
The PassthroughNV decoration must only be used within a geometry
shader.
Any variable decorated with PassthroughNV must be declared using the
Input storage class.
The PassthroughNV decoration must not be used with any of:
-
an input primitive type other than
InputPoints,InputLines, orTriangles, as specified by the mode forOpExecutionMode. -
an invocation count other than one, as specified by the
Invocationsmode forOpExecutionMode. -
an
OpEntryPointwhich statically uses theOpEmitVertexorOpEndPrimitiveinstructions. -
a variable decorated with the
InvocationIdbuilt-in decoration. -
a variable decorated with the
PrimitiveIdbuilt-in decoration that is declared using theInputstorage class.
22.5.2. Passthrough Interface Matching
When a passthrough geometry shader is in use, the Interface Matching rules involving the geometry shader input and output interfaces operate as described in this section.
For the purposes of matching passthrough geometry shader inputs with outputs
of the previous pipeline stages, the PassthroughNV decoration is
ignored.
For the purposes of matching the outputs of the geometry shader with
subsequent pipeline stages, each input variable with the PassthroughNV
decoration is considered to add an equivalent output variable with the same
type, decoration (other than PassthroughNV), number, and declaration
order on the output interface.
The output variable declaration corresponding to an input variable decorated
with PassthroughNV will be identical to the input declaration, except
that the outermost array dimension of such variables is removed.
The output block declaration corresponding to an input block decorated with
PassthroughNV or having members decorated with PassthroughNV will
be identical to the input declaration, except that the outermost array
dimension of such declaration is removed.
If an input block is decorated with PassthroughNV, the equivalent
output block contains all the members of the input block.
Otherwise, the equivalent output block contains only those input block
members decorated with PassthroughNV.
All members of the corresponding output block are assigned Location and
Component decorations identical to those assigned to the corresponding
input block members.
Output variables and blocks generated from inputs decorated with
PassthroughNV will only exist for the purposes of interface matching;
these declarations are not available to geometry shader code or listed in
the module interface.
For the purposes of component counting, passthrough geometry shaders count
all statically used input variable components declared with the
PassthroughNV decoration as output components as well, since their
values will be copied to the output primitive produced by the geometry
shader.
23. Fixed-Function Vertex Post-Processing
After programmable vertex processing, the following fixed-function operations are applied to vertices of the resulting primitives:
-
Viewport swizzle (see Viewport Swizzle)
-
Flat shading (see Flat Shading).
-
Primitive clipping, including client-defined half-spaces (see Primitive Clipping).
-
Shader output attribute clipping (see Clipping Shader Outputs).
-
Clip space W scaling (see Controlling Viewport W Scaling).
-
Perspective division on clip coordinates (see Coordinate Transformations).
-
Viewport mapping, including depth range scaling (see Controlling the Viewport).
-
Front face determination for polygon primitives (see Basic Polygon Rasterization).
|
editing-note
TODO:Odd that this one link to a different chapter is in this list. |
Next, rasterization is performed on primitives as described in chapter Rasterization.
23.1. Viewport Swizzle
Each primitive sent to a given viewport has a swizzle and optional negation
applied to its clip coordinates.
The swizzle that is applied depends on the viewport index, and is controlled
by the VkPipelineViewportSwizzleStateCreateInfoNV pipeline state:
typedef struct VkPipelineViewportSwizzleStateCreateInfoNV {
VkStructureType sType;
const void* pNext;
VkPipelineViewportSwizzleStateCreateFlagsNV flags;
uint32_t viewportCount;
const VkViewportSwizzleNV* pViewportSwizzles;
} VkPipelineViewportSwizzleStateCreateInfoNV;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
viewportCountis the number of viewport swizzles used by the pipeline. -
pViewportSwizzlesis a pointer to an array of VkViewportSwizzleNV structures, defining the viewport swizzles.
typedef VkFlags VkPipelineViewportSwizzleStateCreateFlagsNV;
VkPipelineViewportSwizzleStateCreateFlagsNV is a bitmask type for
setting a mask, but is currently reserved for future use.
The VkPipelineViewportSwizzleStateCreateInfoNV state is set by adding
an instance of this structure to the pNext chain of an instance of the
VkPipelineViewportStateCreateInfo structure and setting the graphics
pipeline state with vkCreateGraphicsPipelines.
Each viewport specified from 0 to viewportCount - 1 has its x,y,z,w
swizzle state set to the corresponding x, y, z and w
in the VkViewportSwizzleNV structure.
Each component is of type VkViewportCoordinateSwizzleNV, which
determines the type of swizzle for that component.
The value of x computes the new x component of the position as:
if (x == VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_X_NV) x' = x; if (x == VK_VIEWPORT_COORDINATE_SWIZZLE_NEGATIVE_X_NV) x' = -x; if (x == VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_Y_NV) x' = y; if (x == VK_VIEWPORT_COORDINATE_SWIZZLE_NEGATIVE_Y_NV) x' = -y; if (x == VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_Z_NV) x' = z; if (x == VK_VIEWPORT_COORDINATE_SWIZZLE_NEGATIVE_Z_NV) x' = -z; if (x == VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_W_NV) x' = w; if (x == VK_VIEWPORT_COORDINATE_SWIZZLE_NEGATIVE_W_NV) x' = -w;
Similar selections are performed for the y, z, and w
coordinates.
This swizzling is applied before clipping and perspective divide.
If the swizzle for an active viewport index is not specified, the swizzle
for x is VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_X_NV, y
is VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_Y_NV, z is
VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_Z_NV and w is
VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_W_NV.
Viewport swizzle parameters are specified by setting the pNext pointer
of VkGraphicsPipelineCreateInfo to point to an instance of
VkPipelineViewportSwizzleStateCreateInfoNV.
VkPipelineViewportSwizzleStateCreateInfoNV uses
VkViewportSwizzleNV to set the viewport swizzle parameters.
The VkViewportSwizzleNV structure is defined as:
typedef struct VkViewportSwizzleNV {
VkViewportCoordinateSwizzleNV x;
VkViewportCoordinateSwizzleNV y;
VkViewportCoordinateSwizzleNV z;
VkViewportCoordinateSwizzleNV w;
} VkViewportSwizzleNV;
-
xis a VkViewportCoordinateSwizzleNV value specifying the swizzle operation to apply to the x component of the primitive -
yis a VkViewportCoordinateSwizzleNV value specifying the swizzle operation to apply to the y component of the primitive -
zis a VkViewportCoordinateSwizzleNV value specifying the swizzle operation to apply to the z component of the primitive -
wis a VkViewportCoordinateSwizzleNV value specifying the swizzle operation to apply to the w component of the primitive
Possible values of the VkViewportSwizzleNV::x, y, z,
and w members, specifying swizzling of the corresponding components of
primitives, are:
typedef enum VkViewportCoordinateSwizzleNV {
VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_X_NV = 0,
VK_VIEWPORT_COORDINATE_SWIZZLE_NEGATIVE_X_NV = 1,
VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_Y_NV = 2,
VK_VIEWPORT_COORDINATE_SWIZZLE_NEGATIVE_Y_NV = 3,
VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_Z_NV = 4,
VK_VIEWPORT_COORDINATE_SWIZZLE_NEGATIVE_Z_NV = 5,
VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_W_NV = 6,
VK_VIEWPORT_COORDINATE_SWIZZLE_NEGATIVE_W_NV = 7,
} VkViewportCoordinateSwizzleNV;
These values are described in detail in Viewport Swizzle.
23.2. Flat Shading
Flat shading a vertex output attribute means to assign all vertices of the primitive the same value for that output.
The output values assigned are those of the provoking vertex of the primitive. The provoking vertex depends on the primitive topology, and is generally the “first” vertex of the primitive. For primitives not processed by tessellation or geometry shaders, the provoking vertex is selected from the input vertices according to the following table.
Primitive type of primitive i |
Provoking vertex number |
|
i |
|
2 i |
|
i |
|
3 i |
|
i |
|
i + 1 |
|
4 i + 1 |
|
i + 1 |
|
6 i |
|
2 i |
Flat shading is applied to those vertex attributes that
match fragment input attributes which
are decorated as Flat.
If a geometry shader is active, the output primitive topology is either points, line strips, or triangle strips, and the selection of the provoking vertex behaves according to the corresponding row of the table. If a tessellation evaluation shader is active and a geometry shader is not active, the provoking vertex is undefined but must be one of the vertices of the primitive.
23.3. Primitive Clipping
Primitives are culled against the cull volume and then clipped to the clip volume. In clip coordinates, the view volume is defined by:
This view volume can be further restricted by as many as
VkPhysicalDeviceLimits::maxClipDistances client-defined
half-spaces.
The cull volume is the intersection of up to
VkPhysicalDeviceLimits::maxCullDistances client-defined
half-spaces (if no client-defined cull half-spaces are enabled, culling
against the cull volume is skipped).
A shader must write a single cull distance for each enabled cull half-space
to elements of the CullDistance array.
If the cull distance for any enabled cull half-space is negative for all of
the vertices of the primitive under consideration, the primitive is
discarded.
Otherwise the primitive is clipped against the clip volume as defined below.
The clip volume is the intersection of up to
VkPhysicalDeviceLimits::maxClipDistances client-defined
half-spaces with the view volume (if no client-defined clip half-spaces are
enabled, the clip volume is the view volume).
A shader must write a single clip distance for each enabled clip half-space
to elements of the ClipDistance array.
Clip half-space i is then given by the set of points satisfying the
inequality
-
ci(P) ≥ 0
where ci(P) is the clip distance i at point P. For point primitives, ci(P) is simply the clip distance for the vertex in question. For line and triangle primitives, per-vertex clip distances are interpolated using a weighted mean, with weights derived according to the algorithms described in sections Basic Line Segment Rasterization and Basic Polygon Rasterization, using the perspective interpolation equations.
The number of client-defined clip and cull half-spaces that are enabled is
determined by the explicit size of the built-in arrays ClipDistance and
CullDistance, respectively, declared as an output in the interface of
the entry point of the final shader stage before clipping.
Depth clamping is enabled or disabled via the depthClampEnable enable
of the VkPipelineRasterizationStateCreateInfo structure.
If depth clamping is enabled, the plane equation
-
0 ≤ zc ≤ wc
(see the clip volume definition above) is ignored by view volume clipping (effectively, there is no near or far plane clipping).
If the primitive under consideration is a point or line segment, then clipping passes it unchanged if its vertices lie entirely within the clip volume.
Possible values of
VkPhysicalDevicePointClippingProperties::pointClippingBehavior,
specifying clipping behavior of a point primitive whose vertex lies outside
the clip volume, are:
typedef enum VkPointClippingBehavior {
VK_POINT_CLIPPING_BEHAVIOR_ALL_CLIP_PLANES = 0,
VK_POINT_CLIPPING_BEHAVIOR_USER_CLIP_PLANES_ONLY = 1,
VK_POINT_CLIPPING_BEHAVIOR_ALL_CLIP_PLANES_KHR = VK_POINT_CLIPPING_BEHAVIOR_ALL_CLIP_PLANES,
VK_POINT_CLIPPING_BEHAVIOR_USER_CLIP_PLANES_ONLY_KHR = VK_POINT_CLIPPING_BEHAVIOR_USER_CLIP_PLANES_ONLY,
} VkPointClippingBehavior;
or the equivalent
typedef VkPointClippingBehavior VkPointClippingBehaviorKHR;
-
VK_POINT_CLIPPING_BEHAVIOR_ALL_CLIP_PLANESspecifies that the primitive is discarded if the vertex lies outside any clip plane, including the planes bounding the view volume. -
VK_POINT_CLIPPING_BEHAVIOR_USER_CLIP_PLANES_ONLYspecifies that the primitive is discarded only if the vertex lies outside any user clip plane.
If either of a line segment’s vertices lie outside of the clip volume, the line segment may be clipped, with new vertex coordinates computed for each vertex that lies outside the clip volume. A clipped line segment endpoint lies on both the original line segment and the boundary of the clip volume.
This clipping produces a value, 0 ≤ t ≤ 1, for each clipped vertex. If the coordinates of a clipped vertex are P and the original vertices’ coordinates are P1 and P2, then t is given by
-
P = t P1 + (1-t) P2.
|
editing-note
This is weird - it gives P, not t. |
t is used to clip vertex output attributes as described in Clipping Shader Outputs.
If the primitive is a polygon, it passes unchanged if every one of its edges lie entirely inside the clip volume, and it is discarded if every one of its edges lie entirely outside the clip volume. If the edges of the polygon intersect the boundary of the clip volume, the intersecting edges are reconnected by new edges that lie along the boundary of the clip volume - in some cases requiring the introduction of new vertices into a polygon.
If a polygon intersects an edge of the clip volume’s boundary, the clipped polygon must include a point on this boundary edge.
Primitives rendered with user-defined half-spaces must satisfy a complementarity criterion. Suppose a series of primitives is drawn where each vertex i has a single specified clip distance di (or a number of similarly specified clip distances, if multiple half-spaces are enabled). Next, suppose that the same series of primitives are drawn again with each such clip distance replaced by -di (and the graphics pipeline is otherwise the same). In this case, primitives must not be missing any pixels, and pixels must not be drawn twice in regions where those primitives are cut by the clip planes.
23.4. Clipping Shader Outputs
Next, vertex output attributes are clipped. The output values associated with a vertex that lies within the clip volume are unaffected by clipping. If a primitive is clipped, however, the output values assigned to vertices produced by clipping are clipped.
Let the output values assigned to the two vertices P1 and P2 of an unclipped edge be c1 and c2. The value of t (see Primitive Clipping) for a clipped point P is used to obtain the output value associated with P as
-
c = t c1 + (1-t) c2.
(Multiplying an output value by a scalar means multiplying each of x, y, z, and w by the scalar.)
Since this computation is performed in clip space before division by wc, clipped output values are perspective-correct.
Polygon clipping creates a clipped vertex along an edge of the clip volume’s boundary. This situation is handled by noting that polygon clipping proceeds by clipping against one half-space at a time. Output value clipping is done in the same way, so that clipped points always occur at the intersection of polygon edges (possibly already clipped) with the clip volume’s boundary.
For vertex output attributes whose matching fragment input attributes are
decorated with NoPerspective, the value of t used to obtain the
output value associated with P will be adjusted to produce results
that vary linearly in framebuffer space.
Output attributes of integer or unsigned integer type must always be flat shaded. Flat shaded attributes are constant over the primitive being rasterized (see Basic Line Segment Rasterization and Basic Polygon Rasterization), and no interpolation is performed. The output value c is taken from either c1 or c2, since flat shading has already occurred and the two values are identical.
23.5. Controlling Viewport W Scaling
If viewport W scaling is enabled, the W component of the clip coordinate is modified by the provided coefficients from the corresponding viewport as follows.
-
wc' = xcoeff xc + ycoeff yc + wc
The VkPipelineViewportWScalingStateCreateInfoNV structure is defined
as:
typedef struct VkPipelineViewportWScalingStateCreateInfoNV {
VkStructureType sType;
const void* pNext;
VkBool32 viewportWScalingEnable;
uint32_t viewportCount;
const VkViewportWScalingNV* pViewportWScalings;
} VkPipelineViewportWScalingStateCreateInfoNV;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
viewportWScalingEnablecontrols whether viewport W scaling is enabled. -
viewportCountis the number of viewports used by W scaling, and must match the number of viewports in the pipeline if viewport W scaling is enabled. -
pViewportWScalingsis a pointer to an array ofVkViewportWScalingNVstructures, which define the W scaling parameters for the corresponding viewport. If the viewport W scaling state is dynamic, this member is ignored.
The VkPipelineViewportWScalingStateCreateInfoNV state is set by adding
an instance of this structure to the pNext chain of an instance of the
VkPipelineViewportStateCreateInfo structure and setting the graphics
pipeline state with vkCreateGraphicsPipelines.
If the bound pipeline state object was not created with the
VK_DYNAMIC_STATE_VIEWPORT_W_SCALING_NV dynamic state enabled, viewport
W scaling parameters are specified using the pViewportWScalings
member of VkPipelineViewportWScalingStateCreateInfoNV in the pipeline
state object.
If the pipeline state object was created with the
VK_DYNAMIC_STATE_VIEWPORT_W_SCALING_NV dynamic state enabled, the
viewport transformation parameters are dynamically set and changed with the
command:
void vkCmdSetViewportWScalingNV(
VkCommandBuffer commandBuffer,
uint32_t firstViewport,
uint32_t viewportCount,
const VkViewportWScalingNV* pViewportWScalings);
-
commandBufferis the command buffer into which the command will be recorded. -
firstViewportis the index of the first viewport whose parameters are updated by the command. -
viewportCountis the number of viewports whose parameters are updated by the command. -
pViewportWScalingsis a pointer to an array of VkViewportWScalingNV structures specifying viewport parameters.
The viewport parameters taken from element i of
pViewportWScalings replace the current state for the viewport index
firstViewport + i, for i in [0,
viewportCount).
Both VkPipelineViewportWScalingStateCreateInfoNV and
vkCmdSetViewportWScalingNV use VkViewportWScalingNV to set the
viewport transformation parameters.
The VkViewportWScalingNV structure is defined as:
typedef struct VkViewportWScalingNV {
float xcoeff;
float ycoeff;
} VkViewportWScalingNV;
-
xcoeffandycoeffare the viewport’s W scaling factor for x and y respectively.
23.6. Coordinate Transformations
Clip coordinates for a vertex result from shader execution, which yields a
vertex coordinate Position.
Perspective division on clip coordinates yields normalized device coordinates, followed by a viewport transformation (see Controlling the Viewport) to convert these coordinates into framebuffer coordinates.
If a vertex in clip coordinates has a position given by
then the vertex’s normalized device coordinates are
23.7. Controlling the Viewport
The viewport transformation is determined by the selected viewport’s width and height in pixels, px and py, respectively, and its center (ox, oy) (also in pixels), as well as its depth range min and max determining a depth range scale value pz and a depth range bias value oz (defined below). The vertex’s framebuffer coordinates (xf, yf, zf) are given by
-
xf = (px / 2) xd + ox
-
yf = (py / 2) yd + oy
-
zf = pz × zd + oz
Multiple viewports are available, numbered zero up to
VkPhysicalDeviceLimits::maxViewports minus one.
The number of viewports used by a pipeline is controlled by the
viewportCount member of the VkPipelineViewportStateCreateInfo
structure used in pipeline creation.
The VkPipelineViewportStateCreateInfo structure is defined as:
typedef struct VkPipelineViewportStateCreateInfo {
VkStructureType sType;
const void* pNext;
VkPipelineViewportStateCreateFlags flags;
uint32_t viewportCount;
const VkViewport* pViewports;
uint32_t scissorCount;
const VkRect2D* pScissors;
} VkPipelineViewportStateCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
viewportCountis the number of viewports used by the pipeline. -
pViewportsis a pointer to an array of VkViewport structures, defining the viewport transforms. If the viewport state is dynamic, this member is ignored. -
scissorCountis the number of scissors and must match the number of viewports. -
pScissorsis a pointer to an array ofVkRect2Dstructures which define the rectangular bounds of the scissor for the corresponding viewport. If the scissor state is dynamic, this member is ignored.
typedef VkFlags VkPipelineViewportStateCreateFlags;
VkPipelineViewportStateCreateFlags is a bitmask type for setting a
mask, but is currently reserved for future use.
A vertex processing stage may direct each primitive to zero or more
viewports.
The destination viewports for a primitive are selected by the last active
vertex processing stage that has an output variable decorated with
ViewportIndex (selecting a single viewport) or ViewportMaskNV
(selecting multiple viewports).
The viewport transform uses the viewport corresponding to either the value
assigned to ViewportIndex or one of the bits set in
ViewportMaskNV, and taken from an implementation-dependent vertex of
each primitive.
If ViewportIndex or any of the bits in ViewportMaskNV are outside
the range zero to viewportCount minus one for a primitive, or if the
last active vertex processing stage did not assign a value to either
ViewportIndex or ViewportMaskNV for all vertices of a primitive
due to flow control, the results of the viewport transformation of the
vertices of such primitives are undefined.
If the last vertex processing stage does not have an output decorated with
ViewportIndex or ViewportMaskNV, the viewport numbered zero is
used by the viewport transformation.
A single vertex can be used in more than one individual primitive, in
primitives such as VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP.
In this case, the viewport transformation is applied separately for each
primitive.
If the bound pipeline state object was not created with the
VK_DYNAMIC_STATE_VIEWPORT dynamic state enabled, viewport
transformation parameters are specified using the pViewports member of
VkPipelineViewportStateCreateInfo in the pipeline state object.
If the pipeline state object was created with the
VK_DYNAMIC_STATE_VIEWPORT dynamic state enabled, the viewport
transformation parameters are dynamically set and changed with the command:
void vkCmdSetViewport(
VkCommandBuffer commandBuffer,
uint32_t firstViewport,
uint32_t viewportCount,
const VkViewport* pViewports);
-
commandBufferis the command buffer into which the command will be recorded. -
firstViewportis the index of the first viewport whose parameters are updated by the command. -
viewportCountis the number of viewports whose parameters are updated by the command. -
pViewportsis a pointer to an array of VkViewport structures specifying viewport parameters.
The viewport parameters taken from element i of pViewports
replace the current state for the viewport index firstViewport
+ i, for i in [0, viewportCount).
Both VkPipelineViewportStateCreateInfo and vkCmdSetViewport use
VkViewport to set the viewport transformation parameters.
The VkViewport structure is defined as:
typedef struct VkViewport {
float x;
float y;
float width;
float height;
float minDepth;
float maxDepth;
} VkViewport;
-
xandyare the viewport’s upper left corner (x,y). -
widthandheightare the viewport’s width and height, respectively. -
minDepthandmaxDepthare the depth range for the viewport. It is valid forminDepthto be greater than or equal tomaxDepth.
The framebuffer depth coordinate zf may be represented using
either a fixed-point or floating-point representation.
However, a floating-point representation must be used if the depth/stencil
attachment has a floating-point depth component.
If an m-bit fixed-point representation is used, we assume that it
represents each value \(\frac{k}{2^m - 1}\), where k ∈ {
0, 1, …, 2m-1 }, as k (e.g. 1.0 is represented in binary as a
string of all ones).
The viewport parameters shown in the above equations are found from these values as
-
ox =
x+width/ 2 -
oy =
y+height/ 2 -
oz =
minDepth -
px =
width -
py =
height -
pz =
maxDepth-minDepth.
The application can specify a negative term for height, which has the
effect of negating the y coordinate in clip space before performing the
transform.
When using a negative height, the application should also adjust the
y value to point to the lower left corner of the viewport instead of
the upper left corner.
Using the negative height allows the application to avoid having to
negate the y component of the Position output from the last vertex
processing stage in shaders that also target other graphics APIs.
The width and height of the implementation-dependent maximum viewport dimensions must be greater than or equal to the width and height of the largest image which can be created and attached to a framebuffer.
The floating-point viewport bounds are represented with an implementation-dependent precision.
24. Rasterization
Rasterization is the process by which a primitive is converted to a two-dimensional image. Each point of this image contains associated data such as depth, color, or other attributes.
Rasterizing a primitive begins by determining which squares of an integer grid in framebuffer coordinates are occupied by the primitive, and assigning one or more depth values to each such square. This process is described below for points, lines, and polygons.
A grid square, including its (x,y) framebuffer coordinates, z (depth), and associated data added by fragment shaders, is called a fragment. A fragment is located by its upper left corner, which lies on integer grid coordinates.
Rasterization operations also refer to a fragment’s sample locations, which are offset by subpixel fractional values from its upper left corner. The rasterization rules for points, lines, and triangles involve testing whether each sample location is inside the primitive. Fragments need not actually be square, and rasterization rules are not affected by the aspect ratio of fragments. Display of non-square grids, however, will cause rasterized points and line segments to appear fatter in one direction than the other.
We assume that fragments are square, since it simplifies antialiasing and texturing. After rasterization, fragments are processed by the early per-fragment tests, if enabled.
Several factors affect rasterization, including the members of
VkPipelineRasterizationStateCreateInfo and
VkPipelineMultisampleStateCreateInfo.
The VkPipelineRasterizationStateCreateInfo structure is defined as:
typedef struct VkPipelineRasterizationStateCreateInfo {
VkStructureType sType;
const void* pNext;
VkPipelineRasterizationStateCreateFlags flags;
VkBool32 depthClampEnable;
VkBool32 rasterizerDiscardEnable;
VkPolygonMode polygonMode;
VkCullModeFlags cullMode;
VkFrontFace frontFace;
VkBool32 depthBiasEnable;
float depthBiasConstantFactor;
float depthBiasClamp;
float depthBiasSlopeFactor;
float lineWidth;
} VkPipelineRasterizationStateCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
depthClampEnablecontrols whether to clamp the fragment’s depth values instead of clipping primitives to the z planes of the frustum, as described in Primitive Clipping. -
rasterizerDiscardEnablecontrols whether primitives are discarded immediately before the rasterization stage. -
polygonModeis the triangle rendering mode. See VkPolygonMode. -
cullModeis the triangle facing direction used for primitive culling. See VkCullModeFlagBits. -
frontFaceis a VkFrontFace value specifying the front-facing triangle orientation to be used for culling. -
depthBiasEnablecontrols whether to bias fragment depth values. -
depthBiasConstantFactoris a scalar factor controlling the constant depth value added to each fragment. -
depthBiasClampis the maximum (or minimum) depth bias of a fragment. -
depthBiasSlopeFactoris a scalar factor applied to a fragment’s slope in depth bias calculations. -
lineWidthis the width of rasterized line segments.
The application can also add a
VkPipelineRasterizationStateRasterizationOrderAMD structure to the
pNext chain of a VkPipelineRasterizationStateCreateInfo
structure.
This structure enables selecting the rasterization order to use when
rendering with the corresponding graphics pipeline as described in
Rasterization Order.
typedef VkFlags VkPipelineRasterizationStateCreateFlags;
VkPipelineRasterizationStateCreateFlags is a bitmask type for setting
a mask, but is currently reserved for future use.
The VkPipelineMultisampleStateCreateInfo structure is defined as:
typedef struct VkPipelineMultisampleStateCreateInfo {
VkStructureType sType;
const void* pNext;
VkPipelineMultisampleStateCreateFlags flags;
VkSampleCountFlagBits rasterizationSamples;
VkBool32 sampleShadingEnable;
float minSampleShading;
const VkSampleMask* pSampleMask;
VkBool32 alphaToCoverageEnable;
VkBool32 alphaToOneEnable;
} VkPipelineMultisampleStateCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
rasterizationSamplesis a VkSampleCountFlagBits specifying the number of samples per pixel used in rasterization. -
sampleShadingEnablecan be used to enable Sample Shading. -
minSampleShadingspecifies a minimum fraction of sample shading ifsampleShadingEnableis set toVK_TRUE. -
pSampleMaskis a bitmask of static coverage information that is ANDed with the coverage information generated during rasterization, as described in Sample Mask. -
alphaToCoverageEnablecontrols whether a temporary coverage value is generated based on the alpha component of the fragment’s first color output as specified in the Multisample Coverage section. -
alphaToOneEnablecontrols whether the alpha component of the fragment’s first color output is replaced with one as described in Multisample Coverage.
typedef VkFlags VkPipelineMultisampleStateCreateFlags;
VkPipelineMultisampleStateCreateFlags is a bitmask type for setting a
mask, but is currently reserved for future use.
Rasterization only produces fragments corresponding to pixels in the framebuffer. Fragments which would be produced by application of any of the primitive rasterization rules described below but which lie outside the framebuffer are not produced, nor are they processed by any later stage of the pipeline, including any of the early per-fragment tests described in Early Per-Fragment Tests.
Surviving fragments are processed by fragment shaders. Fragment shaders determine associated data for fragments, and can also modify or replace their assigned depth values.
If the subpass for which this pipeline is being created uses color and/or
depth/stencil attachments, then rasterizationSamples must be the same
as the maximum of the sample counts of those subpass attachments.
If the subpass for which this pipeline is being created does not use color
or depth/stencil attachments, rasterizationSamples must follow the
rules for a zero-attachment subpass.
24.1. Discarding Primitives Before Rasterization
Primitives are discarded before rasterization if the
rasterizerDiscardEnable member of
VkPipelineRasterizationStateCreateInfo is enabled.
When enabled, primitives are discarded after they are processed by the last
active shader stage in the pipeline before rasterization.
24.2. Rasterization Order
Within a subpass of a render pass instance, for a given (x,y,layer,sample) sample location, the following operations are guaranteed to execute in rasterization order, for each separate primitive that includes that sample location:
Each of these operations is atomically executed for each primitive and sample location.
Execution of these operations for each primitive in a subpass occurs in an order determined by the application.
The rasterization order to use for a graphics pipeline is specified by
adding a VkPipelineRasterizationStateRasterizationOrderAMD structure
to the pNext chain of a VkPipelineRasterizationStateCreateInfo
structure.
The VkPipelineRasterizationStateRasterizationOrderAMD structure is
defined as:
typedef struct VkPipelineRasterizationStateRasterizationOrderAMD {
VkStructureType sType;
const void* pNext;
VkRasterizationOrderAMD rasterizationOrder;
} VkPipelineRasterizationStateRasterizationOrderAMD;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
rasterizationOrderis a VkRasterizationOrderAMD value specifying the primitive rasterization order to use.
If the VK_AMD_rasterization_order device extension is not enabled or
the application does not request a particular rasterization order through
specifying a VkPipelineRasterizationStateRasterizationOrderAMD
structure then the rasterization order used by the graphics pipeline
defaults to VK_RASTERIZATION_ORDER_STRICT_AMD.
Possible values of
VkPipelineRasterizationStateRasterizationOrderAMD::rasterizationOrder,
specifying the primitive rasterization order, are:
typedef enum VkRasterizationOrderAMD {
VK_RASTERIZATION_ORDER_STRICT_AMD = 0,
VK_RASTERIZATION_ORDER_RELAXED_AMD = 1,
} VkRasterizationOrderAMD;
-
VK_RASTERIZATION_ORDER_STRICT_AMDspecifies that operations for each primitive in a subpass must occur in primitive order. -
VK_RASTERIZATION_ORDER_RELAXED_AMDspecifies that operations for each primitive in a subpass may not occur in primitive order.
24.3. Multisampling
Multisampling is a mechanism to antialias all Vulkan primitives: points, lines, and polygons. The technique is to sample all primitives multiple times at each pixel. Each sample in each framebuffer attachment has storage for a color, depth, and/or stencil value, such that per-fragment operations apply to each sample independently. The color sample values can be later resolved to a single color (see Resolving Multisample Images and the Render Pass chapter for more details on how to resolve multisample images to non-multisample images).
Vulkan defines rasterization rules for single-sample modes in a way that is equivalent to a multisample mode with a single sample in the center of each pixel.
Each fragment includes a coverage value with rasterizationSamples bits
(see Sample Mask).
Each fragment includes rasterizationSamples depth values and sets of
associated data.
An implementation may choose to assign the same associated data to more
than one sample.
The location for evaluating such associated data may be anywhere within the
pixel including the pixel center or any of the sample locations.
When rasterizationSamples is VK_SAMPLE_COUNT_1_BIT, the pixel
center must be used.
The different associated data values need not all be evaluated at the same
location.
Each pixel fragment thus consists of integer x and y grid coordinates,
rasterizationSamples depth values and sets of associated data, and a
coverage value with rasterizationSamples bits.
It is understood that each pixel has rasterizationSamples locations
associated with it.
These locations are exact positions, rather than regions or areas, and each
is referred to as a sample point.
The sample points associated with a pixel must be located inside or on the
boundary of the unit square that is considered to bound the pixel.
Furthermore, the relative locations of sample points may be identical for
each pixel in the framebuffer, or they may differ.
If the current pipeline includes a fragment shader with one or more
variables in its interface decorated with Sample and Input, the
data associated with those variables will be assigned independently for each
sample.
The values for each sample must be evaluated at the location of the sample.
The data associated with any other variables not decorated with Sample
and Input need not be evaluated independently for each sample.
If the standardSampleLocations member of VkPhysicalDeviceLimits
is VK_TRUE, then the sample counts VK_SAMPLE_COUNT_1_BIT,
VK_SAMPLE_COUNT_2_BIT, VK_SAMPLE_COUNT_4_BIT,
VK_SAMPLE_COUNT_8_BIT, and VK_SAMPLE_COUNT_16_BIT have sample
locations as listed in the following table, with the ith entry in
the table corresponding to bit i in the sample masks.
VK_SAMPLE_COUNT_32_BIT and VK_SAMPLE_COUNT_64_BIT do not have
standard sample locations.
Locations are defined relative to an origin in the upper left corner of the
pixel.
|
|
|
|
|
(0.5,0.5) |
(0.25,0.25) |
(0.375, 0.125) |
(0.5625, 0.3125) |
(0.5625, 0.5625) |
Color images created with multiple samples per pixel use a compression
technique where there are two arrays of data associated with each pixel.
The first array contains one element per sample where each element stores an
index to the second array defining the fragment mask of the pixel.
The second array contains one element per color fragment and each element
stores a unique color value in the format of the image.
With this compression technique it’s not always necessary to actually use
unique storage locations for each color sample: when multiple samples share
the same color value the fragment mask may have two samples referring to
the same color fragment.
The number of color fragments is determined by the samples member of
the VkImageCreateInfo structure used to create the image.
The VK_AMD_shader_fragment_mask device extension provides shader
instructions enabling the application to get direct access to the fragment
mask and the individual color fragment values.
24.4. Custom Sample Locations
Applications can also control the sample locations used for rasterization.
If the pNext chain of the VkPipelineMultisampleStateCreateInfo
structure specified at pipeline creation time includes an instance of the
VkPipelineSampleLocationsStateCreateInfoEXT structure, then that
structure controls the sample locations used when rasterizing primitives
with the pipeline.
The VkPipelineSampleLocationsStateCreateInfoEXT structure is defined
as:
typedef struct VkPipelineSampleLocationsStateCreateInfoEXT {
VkStructureType sType;
const void* pNext;
VkBool32 sampleLocationsEnable;
VkSampleLocationsInfoEXT sampleLocationsInfo;
} VkPipelineSampleLocationsStateCreateInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
sampleLocationsEnablecontrols whether custom sample locations are used. IfsampleLocationsEnableisVK_FALSE, the default sample locations are used and the values specified insampleLocationsInfoare ignored. -
sampleLocationsInfois the sample locations to use during rasterization ifsampleLocationsEnableisVK_TRUEand the graphics pipeline isn’t created withVK_DYNAMIC_STATE_SAMPLE_LOCATIONS_EXT.
The VkSampleLocationsInfoEXT structure is defined as:
typedef struct VkSampleLocationsInfoEXT {
VkStructureType sType;
const void* pNext;
VkSampleCountFlagBits sampleLocationsPerPixel;
VkExtent2D sampleLocationGridSize;
uint32_t sampleLocationsCount;
const VkSampleLocationEXT* pSampleLocations;
} VkSampleLocationsInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
sampleLocationsPerPixelis a VkSampleCountFlagBits specifying the number of sample locations per pixel. -
sampleLocationGridSizeis the size of the sample location grid to select custom sample locations for. -
sampleLocationsCountis the number of sample locations inpSampleLocations. -
pSampleLocationsis an array ofsampleLocationsCountVkSampleLocationEXT structures.
This structure can be used either to specify the sample locations to be
used for rendering or to specify the set of sample locations an image
subresource has been last rendered with for the purposes of layout
transitions of depth/stencil images created with
VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT.
The sample locations in pSampleLocations specify
sampleLocationsPerPixel number of sample locations for each pixel in
the grid of the size specified in sampleLocationGridSize.
The sample location for sample i at the pixel grid location
(x,y) is taken from pSampleLocations[(x + y *
sampleLocationGridSize.width)
* sampleLocationsPerPixel + i].
The VkSampleLocationEXT structure is defined as:
typedef struct VkSampleLocationEXT {
float x;
float y;
} VkSampleLocationEXT;
-
xis the horizontal coordinate of the sample’s location. -
yis the vertical coordinate of the sample’s location.
The domain space of the sample location coordinates has an upper-left origin within the pixel in framebuffer space.
The values specified in a VkSampleLocationEXT structure are always
clamped to the implementation-dependent sample location coordinate range
[sampleLocationCoordinateRange[0],sampleLocationCoordinateRange[1]]
that can be queried by chaining the
VkPhysicalDeviceSampleLocationsPropertiesEXT structure to the
pNext chain of VkPhysicalDeviceProperties2.
The custom sample locations used for rasterization when
VkPipelineSampleLocationsStateCreateInfoEXT::sampleLocationsEnable
is VK_TRUE are specified by the
VkPipelineSampleLocationsStateCreateInfoEXT::sampleLocationsInfo
property of the bound graphics pipeline, if the pipeline was not created
with VK_DYNAMIC_STATE_SAMPLE_LOCATIONS_EXT enabled.
Otherwise, the sample locations used for rasterization are set by calling
vkCmdSetSampleLocationsEXT:
void vkCmdSetSampleLocationsEXT(
VkCommandBuffer commandBuffer,
const VkSampleLocationsInfoEXT* pSampleLocationsInfo);
-
commandBufferis the command buffer into which the command will be recorded. -
pSampleLocationsInfois the sample locations state to set.
24.5. Sample Shading
Sample shading can be used to specify a minimum number of unique samples to
process for each fragment.
If sample shading is enabled an implementation must provide a minimum of
max(⌈ minSampleShadingFactor × totalSamples
⌉, 1) unique associated data for each fragment, where
minSampleShadingFactor is the minimum fraction of sample shading and
totalSamples is
the number of samples of the color attachments used in the subpass or, if
the subpass does not use any color attachments,
the value of
VkPipelineMultisampleStateCreateInfo::pname.rasterizationSamples
specified at pipeline creation time.
These are associated with the samples in an implementation-dependent manner.
When minSampleShadingFactor is 1.0, a separate set of associated data
are evaluated for each sample, and each set of values is evaluated at the
sample location.
Sample shading is enabled for a graphics pipeline:
-
If the interface of the fragment shader entry point of the graphics pipeline includes an input variable decorated with
SampleIdorSamplePosition. In this caseminSampleShadingFactortakes the value 1.0. -
Else if the
sampleShadingEnablemember of the VkPipelineMultisampleStateCreateInfo structure specified when creating the graphics pipeline is set toVK_TRUE. In this caseminSampleShadingFactortakes the value of VkPipelineMultisampleStateCreateInfo::minSampleShading.
Otherwise, sample shading is considered disabled.
24.6. Points
A point is drawn by generating a set of fragments in the shape of a square
centered around the vertex of the point.
Each vertex has an associated point size that controls the width/height of
that square.
The point size is taken from the (potentially clipped) shader built-in
PointSize written by:
-
the geometry shader, if active;
-
the tessellation evaluation shader, if active and no geometry shader is active;
-
the vertex shader, otherwise
and clamped to the implementation-dependent point size range
[pointSizeRange[0],pointSizeRange[1]].
If the value written to PointSize is less than or equal to zero, or if
no value was written to PointSize, results are undefined.
Not all point sizes need be supported, but the size 1.0 must be supported.
The range of supported sizes and the size of evenly-spaced gradations within
that range are implementation-dependent.
The range and gradations are obtained from the pointSizeRange and
pointSizeGranularity members of VkPhysicalDeviceLimits.
If, for instance, the size range is from 0.1 to 2.0 and the gradation size
is 0.1, then the size 0.1, 0.2, …, 1.9, 2.0 are supported.
Additional point sizes may also be supported.
There is no requirement that these sizes be equally spaced.
If an unsupported size is requested, the nearest supported size is used
instead.
24.6.1. Basic Point Rasterization
Point rasterization produces a fragment for each framebuffer pixel with one or more sample points that intersect a region centered at the point’s (xf,yf). This region is a square with side equal to the current point size. Coverage bits that correspond to sample points that intersect the region are 1, other coverage bits are 0.
All fragments produced in rasterizing a point are assigned the same
associated data, which are those of the vertex corresponding to the point.
However, the fragment shader built-in PointCoord contains point sprite
texture coordinates.
The s and t point sprite texture coordinates vary from zero to
one across the point horizontally left-to-right and top-to-bottom,
respectively.
The following formulas are used to evaluate s and t:
where size is the point’s size, (xp,yp) is the location at which
the point sprite coordinates are evaluated - this may be the framebuffer
coordinates of the pixel center (i.e. at the half-integer) or the location
of a sample, and (xf,yf) is the exact, unrounded framebuffer
coordinate of the vertex for the point.
When rasterizationSamples is VK_SAMPLE_COUNT_1_BIT, the pixel
center must be used.
24.7. Line Segments
A line is drawn by generating a set of fragments overlapping a rectangle centered on the line segment. Each line segment has an associated width that controls the width of that rectangle.
The line width is specified by the
VkPipelineRasterizationStateCreateInfo::lineWidth property of
the currently active pipeline, if the pipeline was not created with
VK_DYNAMIC_STATE_LINE_WIDTH enabled.
Otherwise, the line width is set by calling vkCmdSetLineWidth:
void vkCmdSetLineWidth(
VkCommandBuffer commandBuffer,
float lineWidth);
-
commandBufferis the command buffer into which the command will be recorded. -
lineWidthis the width of rasterized line segments.
Not all line widths need be supported for line segment rasterization, but
width 1.0 antialiased segments must be provided.
The range and gradations are obtained from the lineWidthRange and
lineWidthGranularity members of VkPhysicalDeviceLimits.
If, for instance, the size range is from 0.1 to 2.0 and the gradation size
is 0.1, then the size 0.1, 0.2, …, 1.9, 2.0 are supported.
Additional line widths may also be supported.
There is no requirement that these widths be equally spaced.
If an unsupported width is requested, the nearest supported width is used
instead.
24.7.1. Basic Line Segment Rasterization
Rasterized line segments produce fragments which intersect a rectangle centered on the line segment. Two of the edges are parallel to the specified line segment; each is at a distance of one-half the current width from that segment in directions perpendicular to the direction of the line. The other two edges pass through the line endpoints and are perpendicular to the direction of the specified line segment. Coverage bits that correspond to sample points that intersect the rectangle are 1, other coverage bits are 0.
Next we specify how the data associated with each rasterized fragment are
obtained.
Let pr = (xd, yd) be the framebuffer coordinates at which
associated data are evaluated.
This may be the pixel center of a fragment or the location of a sample
within the fragment.
When rasterizationSamples is VK_SAMPLE_COUNT_1_BIT, the pixel
center must be used.
Let pa = (xa, ya) and pb = (xb,yb) be
initial and final endpoints of the line segment, respectively.
Set
(Note that t = 0 at p_a and t = 1 at pb. Also note that this calculation projects the vector from pa to pr onto the line, and thus computes the normalized distance of the fragment along the line.)
The value of an associated datum f for the fragment, whether it be a shader output or the clip w coordinate, must be determined using perspective interpolation:
where fa and fb are the data associated with the starting and ending endpoints of the segment, respectively; wa and wb are the clip w coordinates of the starting and ending endpoints of the segments, respectively.
Depth values for lines must be determined using linear interpolation:
-
z = (1 - t) za + t zb
where za and zb are the depth values of the starting and ending endpoints of the segment, respectively.
The NoPerspective and Flat
interpolation decorations can be used
with fragment shader inputs to declare how they are interpolated.
When neither decoration is applied, perspective interpolation is performed as described above.
When the NoPerspective decoration is used, linear interpolation is performed in the same fashion as for depth values,
as described above.
When the Flat decoration is used, no interpolation is performed, and
outputs are taken from the corresponding input value of the
provoking vertex corresponding to that
primitive.
The above description documents the preferred method of line rasterization,
and must be used when the implementation advertises the strictLines
limit in VkPhysicalDeviceLimits as VK_TRUE.
When strictLines is VK_FALSE, the edges of the lines are
generated as a parallelogram surrounding the original line.
The major axis is chosen by noting the axis in which there is the greatest
distance between the line start and end points.
If the difference is equal in both directions then the X axis is chosen as
the major axis.
Edges 2 and 3 are aligned to the minor axis and are centered on the
endpoints of the line as in Non strict lines, and each is
lineWidth long.
Edges 0 and 1 are parallel to the line and connect the endpoints of edges 2
and 3.
Coverage bits that correspond to sample points that intersect the
parallelogram are 1, other coverage bits are 0.
Samples that fall exactly on the edge of the parallelogram follow the polygon rasterization rules.
Interpolation occurs as if the parallelogram was decomposed into two triangles where each pair of vertices at each end of the line has identical attributes.
24.8. Polygons
A polygon results from the decomposition of a triangle strip, triangle fan or a series of independent triangles. Like points and line segments, polygon rasterization is controlled by several variables in the VkPipelineRasterizationStateCreateInfo structure.
24.8.1. Basic Polygon Rasterization
The first step of polygon rasterization is to determine whether the triangle is back-facing or front-facing. This determination is made based on the sign of the (clipped or unclipped) polygon’s area computed in framebuffer coordinates. One way to compute this area is:
where \(x_f^i\) and \(y_f^i\) are the x and y framebuffer coordinates of the ith vertex of the n-vertex polygon (vertices are numbered starting at zero for the purposes of this computation) and i ⊕ 1 is (i + 1) mod n.
The interpretation of the sign of a is determined by the
VkPipelineRasterizationStateCreateInfo::frontFace property of
the currently active pipeline.
Possible values are:
typedef enum VkFrontFace {
VK_FRONT_FACE_COUNTER_CLOCKWISE = 0,
VK_FRONT_FACE_CLOCKWISE = 1,
} VkFrontFace;
-
VK_FRONT_FACE_COUNTER_CLOCKWISEspecifies that a triangle with positive area is considered front-facing. -
VK_FRONT_FACE_CLOCKWISEspecifies that a triangle with negative area is considered front-facing.
Any triangle which is not front-facing is back-facing, including zero-area triangles.
Once the orientation of triangles is determined, they are culled according
to the VkPipelineRasterizationStateCreateInfo::cullMode property
of the currently active pipeline.
Possible values are:
typedef enum VkCullModeFlagBits {
VK_CULL_MODE_NONE = 0,
VK_CULL_MODE_FRONT_BIT = 0x00000001,
VK_CULL_MODE_BACK_BIT = 0x00000002,
VK_CULL_MODE_FRONT_AND_BACK = 0x00000003,
} VkCullModeFlagBits;
-
VK_CULL_MODE_NONEspecifies that no triangles are discarded -
VK_CULL_MODE_FRONT_BITspecifies that front-facing triangles are discarded -
VK_CULL_MODE_BACK_BITspecifies that back-facing triangles are discarded -
VK_CULL_MODE_FRONT_AND_BACKspecifies that all triangles are discarded.
Following culling, fragments are produced for any triangles which have not been discarded.
typedef VkFlags VkCullModeFlags;
VkCullModeFlags is a bitmask type for setting a mask of zero or more
VkCullModeFlagBits.
The rule for determining which fragments are produced by polygon rasterization is called point sampling. The two-dimensional projection obtained by taking the x and y framebuffer coordinates of the polygon’s vertices is formed. Fragments are produced for any pixels for which any sample points lie inside of this polygon. Coverage bits that correspond to sample points that satisfy the point sampling criteria are 1, other coverage bits are 0. Special treatment is given to a sample whose sample location lies on a polygon edge. In such a case, if two polygons lie on either side of a common edge (with identical endpoints) on which a sample point lies, then exactly one of the polygons must result in a covered sample for that fragment during rasterization. As for the data associated with each fragment produced by rasterizing a polygon, we begin by specifying how these values are produced for fragments in a triangle. Define barycentric coordinates for a triangle. Barycentric coordinates are a set of three numbers, a, b, and c, each in the range [0,1], with a + b + c = 1. These coordinates uniquely specify any point p within the triangle or on the triangle’s boundary as
-
p = a pa + b pb + c pc
where pa, pb, and pc are the vertices of the triangle. a, b, and c are determined by:
where A(lmn) denotes the area in framebuffer coordinates of the triangle with vertices l, m, and n.
Denote an associated datum at pa, pb, or pc as fa, fb, or fc, respectively.
The value of an associated datum f for a fragment produced by rasterizing a triangle, whether it be a shader output or the clip w coordinate, must be determined using perspective interpolation:
where wa, wb, and wc are the clip w
coordinates of pa, pb, and pc, respectively.
a, b, and c are the barycentric coordinates of the
location at which the data are produced - this must be a pixel center or
the location of a sample.
When rasterizationSamples is VK_SAMPLE_COUNT_1_BIT, the pixel
center must be used.
Depth values for triangles must be determined using linear interpolation:
-
z = a za + b zb + c zc
where za, zb, and zc are the depth values of pa, pb, and pc, respectively.
The NoPerspective and Flat
interpolation decorations can be used
with fragment shader inputs to declare how they are interpolated.
When neither decoration is applied, perspective interpolation is performed as described above.
When the NoPerspective decoration is used,
linear interpolation is performed in the
same fashion as for depth values, as described above.
When the Flat decoration is used, no interpolation is performed, and
outputs are taken from the corresponding input value of the
provoking vertex corresponding to that
primitive.
When the VK_AMD_shader_explicit_vertex_parameter device extension is
enabled the CustomInterpAMD interpolation decoration can also be used with fragment shader inputs
which indicate that the decorated inputs can only be accessed by the
extended instruction InterpolateAtVertexAMD and allows accessing the
value of the inputs for individual vertices of the primitive.
For a polygon with more than three edges, such as are produced by clipping a triangle, a convex combination of the values of the datum at the polygon’s vertices must be used to obtain the value assigned to each fragment produced by the rasterization algorithm. That is, it must be the case that at every fragment
where n is the number of vertices in the polygon and fi is the value of f at vertex i. For each i, 0 ≤ ai ≤ 1 and \(\sum_{i=1}^{n}a_i = 1\). The values of ai may differ from fragment to fragment, but at vertex i, ai = 1 and aj = 0 for j ≠ i.
|
Note
One algorithm that achieves the required behavior is to triangulate a polygon (without adding any vertices) and then treat each triangle individually as already discussed. A scan-line rasterizer that linearly interpolates data along each edge and then linearly interpolates data across each horizontal span from edge to edge also satisfies the restrictions (in this case, the numerator and denominator of equation [triangle_perspective_interpolation] are iterated independently and a division performed for each fragment). |
24.8.2. Polygon Mode
Possible values of the
VkPipelineRasterizationStateCreateInfo::polygonMode property of
the currently active pipeline, specifying the method of rasterization for
polygons, are:
typedef enum VkPolygonMode {
VK_POLYGON_MODE_FILL = 0,
VK_POLYGON_MODE_LINE = 1,
VK_POLYGON_MODE_POINT = 2,
VK_POLYGON_MODE_FILL_RECTANGLE_NV = 1000153000,
} VkPolygonMode;
-
VK_POLYGON_MODE_POINTspecifies that polygon vertices are drawn as points. -
VK_POLYGON_MODE_LINEspecifies that polygon edges are drawn as line segments. -
VK_POLYGON_MODE_FILLspecifies that polygons are rendered using the polygon rasterization rules in this section. -
VK_POLYGON_MODE_FILL_RECTANGLE_NVspecifies that polygons are rendered using polygon rasterization rules, modified to consider a sample within the primitive if the sample location is inside the axis-aligned bounding box of the triangle after projection. Note that the barycentric weights used in attribute interpolation can extend outside the range [0,1] when these primitives are shaded. Special treatment is given to a sample position on the boundary edge of the bounding box. In such a case, if two rectangles lie on either side of a common edge (with identical endpoints) on which a sample position lies, then exactly one of the triangles must produce a fragment that covers that sample during rasterization.Polygons rendered in
VK_POLYGON_MODE_FILL_RECTANGLE_NVmode may be clipped by the frustum or by user clip planes. If clipping is applied, the triangle is culled rather than clipped.Area calculation and facingness are determined for
VK_POLYGON_MODE_FILL_RECTANGLE_NVmode using the triangle’s vertices.
These modes affect only the final rasterization of polygons: in particular, a polygon’s vertices are shaded and the polygon is clipped and possibly culled before these modes are applied.
24.8.3. Depth Bias
The depth values of all fragments generated by the rasterization of a
polygon can be offset by a single value that is computed for that polygon.
This behavior is controlled by the depthBiasEnable,
depthBiasConstantFactor, depthBiasClamp, and
depthBiasSlopeFactor members of
VkPipelineRasterizationStateCreateInfo, or by the corresponding
parameters to the vkCmdSetDepthBias command if depth bias state is
dynamic.
void vkCmdSetDepthBias(
VkCommandBuffer commandBuffer,
float depthBiasConstantFactor,
float depthBiasClamp,
float depthBiasSlopeFactor);
-
commandBufferis the command buffer into which the command will be recorded. -
depthBiasConstantFactoris a scalar factor controlling the constant depth value added to each fragment. -
depthBiasClampis the maximum (or minimum) depth bias of a fragment. -
depthBiasSlopeFactoris a scalar factor applied to a fragment’s slope in depth bias calculations.
If depthBiasEnable is VK_FALSE, no depth bias is applied and the
fragment’s depth values are unchanged.
depthBiasSlopeFactor scales the maximum depth slope of the polygon,
and depthBiasConstantFactor scales an implementation-dependent
constant that relates to the usable resolution of the depth buffer.
The resulting values are summed to produce the depth bias value which is
then clamped to a minimum or maximum value specified by
depthBiasClamp.
depthBiasSlopeFactor, depthBiasConstantFactor, and
depthBiasClamp can each be positive, negative, or zero.
The maximum depth slope m of a triangle is
where (xf, yf, zf) is a point on the triangle. m may be approximated as
The minimum resolvable difference r is an implementation-dependent
parameter that depends on the depth buffer representation.
It is the smallest difference in framebuffer coordinate z values that
is guaranteed to remain distinct throughout polygon rasterization and in the
depth buffer.
All pairs of fragments generated by the rasterization of two polygons with
otherwise identical vertices, but zf values that differ by
r, will have distinct depth values.
For fixed-point depth buffer representations, r is constant throughout the range of the entire depth buffer. For floating-point depth buffers, there is no single minimum resolvable difference. In this case, the minimum resolvable difference for a given polygon is dependent on the maximum exponent, e, in the range of z values spanned by the primitive. If n is the number of bits in the floating-point mantissa, the minimum resolvable difference, r, for the given primitive is defined as
-
r = 2e-n
If a triangle is rasterized using the
VK_POLYGON_MODE_FILL_RECTANGLE_NV polygon mode, then this minimum
resolvable difference may not be resolvable for samples outside of the
triangle, where the depth is extrapolated.
If no depth buffer is present, r is undefined.
The bias value o for a polygon is
m is computed as described above. If the depth buffer uses a fixed-point representation, m is a function of depth values in the range [0,1], and o is applied to depth values in the same range.
For fixed-point depth buffers, fragment depth values are always limited to
the range [0,1] by clamping after depth bias addition is performed.
Unless the VK_EXT_depth_range_unrestricted extension is enabled,
fragment depth values are clamped even when the depth buffer uses a
floating-point representation.
24.8.4. Conservative Rasterization
Polygon rasterization can be made conservative by setting
conservativeRasterizationMode to
VK_CONSERVATIVE_RASTERIZATION_MODE_OVERESTIMATE_EXT or
VK_CONSERVATIVE_RASTERIZATION_MODE_UNDERESTIMATE_EXT in
VkPipelineRasterizationConservativeStateCreateInfoEXT.
The VkPipelineRasterizationConservativeStateCreateInfoEXT state is set
by adding an instance of this structure to the pNext chain of an
instance of the VkPipelineRasterizationStateCreateInfo structure when
creating the graphics pipeline.
Enabling these modes also affects line and point rasterization if the
implementation sets
VkPhysicalDeviceConservativeRasterizationPropertiesEXT::conservativePointAndLineRasterization
to VK_TRUE.
VkPipelineRasterizationConservativeStateCreateInfoEXT is defined as:
typedef struct VkPipelineRasterizationConservativeStateCreateInfoEXT {
VkStructureType sType;
const void* pNext;
VkPipelineRasterizationConservativeStateCreateFlagsEXT flags;
VkConservativeRasterizationModeEXT conservativeRasterizationMode;
float extraPrimitiveOverestimationSize;
} VkPipelineRasterizationConservativeStateCreateInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
conservativeRasterizationModeis the conservative rasterization mode to use. -
extraPrimitiveOverestimationSizeis the extra size in pixels to increase the generating primitive during conservative rasterization at each of its edges inXandYequally in screen space beyond the base overestimation specified inVkPhysicalDeviceConservativeRasterizationPropertiesEXT::primitiveOverestimationSize.
typedef VkFlags VkPipelineRasterizationConservativeStateCreateFlagsEXT;
VkPipelineRasterizationConservativeStateCreateFlagsEXT is a bitmask
type for setting a mask, but is currently reserved for future use.
Possible values of
VkPipelineRasterizationConservativeStateCreateInfoEXT::conservativeRasterizationMode,
specifying the conservative rasterization mode are:
typedef enum VkConservativeRasterizationModeEXT {
VK_CONSERVATIVE_RASTERIZATION_MODE_DISABLED_EXT = 0,
VK_CONSERVATIVE_RASTERIZATION_MODE_OVERESTIMATE_EXT = 1,
VK_CONSERVATIVE_RASTERIZATION_MODE_UNDERESTIMATE_EXT = 2,
} VkConservativeRasterizationModeEXT;
-
VK_CONSERVATIVE_RASTERIZATION_MODE_DISABLED_EXTspecifies that conservative rasterization is disabled and rasterization proceeds as normal. -
VK_CONSERVATIVE_RASTERIZATION_MODE_OVERESTIMATE_EXTspecifies that conservative rasterization is enabled in overestimation mode. -
VK_CONSERVATIVE_RASTERIZATION_MODE_UNDERESTIMATE_EXTspecifies that conservative rasterization is enabled in underestimation mode.
When overestimate conservative rasterization is enabled, rather than
evaluating coverage at individual sample locations, a determination is made
of whether any portion of the pixel (including its edges and corners) is
covered by the primitive.
If any portion of the pixel is covered, then all bits of the coverage sample
mask for the fragment are enabled.
If the implementation supports
VkPhysicalDeviceConservativeRasterizationPropertiesEXT::conservativeRasterizationPostDepthCoverage
and the
PostDepthCoverage
execution mode is specified the SampleMask built-in input variable will
reflect the coverage after the early per-fragment depth and stencil tests
are applied.
For the purposes of evaluating which pixels are covered by the primitive,
implementations can increase the size of the primitive by up to
VkPhysicalDeviceConservativeRasterizationPropertiesEXT::primitiveOverestimationSize
pixels at each of the primitive edges.
This may increase the number of fragments generated by this primitive and
represents an overestimation of the pixel coverage.
This overestimation size can be increased further by setting the
extraPrimitiveOverestimationSize value above 0.0 in steps of
VkPhysicalDeviceConservativeRasterizationPropertiesEXT::extraPrimitiveOverestimationSizeGranularity
up to and including
VkPhysicalDeviceConservativeRasterizationPropertiesEXT::extraPrimitiveOverestimationSize.
This will: further increase the number of fragments generated by this
primitive.
The actual precision of the overestimation size used for conservative
rasterization may vary between implementations and produce results that
only approximate the primitiveOverestimationSize and
extraPrimitiveOverestimationSizeGranularity properties.
For triangles if VK_CONSERVATIVE_RASTERIZATION_MODE_OVERESTIMATE_EXT
is enabled, fragments will be generated if the primitive area covers any
portion of the pixel, including its edges or corners.
The tie-breaking rule described in Basic Polygon
Rasterization does not apply during conservative rasterization and
coverage is set for all fragments generated from shared edges of polygons.
Degenerate triangles that evaluate to zero area after rasterization, even
for pixels that contain a vertex or edge of the zero-area polygon, will be
culled if
VkPhysicalDeviceConservativeRasterizationPropertiesEXT::degenerateTrianglesRasterized
is VK_FALSE or will generate fragments if
degenerateTrianglesRasterized is VK_TRUE.
The fragment input values for these degenerate triangles take their
attribute and depth values from the provoking vertex.
Degenerate triangles are considered backfacing and the application can
enable backface culling if desired.
Triangles that are zero area before rasterization may be culled regardless.
For lines if VK_CONSERVATIVE_RASTERIZATION_MODE_OVERESTIMATE_EXT is
enabled, and the implementation sets
VkPhysicalDeviceConservativeRasterizationPropertiesEXT::conservativePointAndLineRasterization
to VK_TRUE, fragments will be generated if the line covers any portion
of the pixel, including its edges or corners.
Degenerate lines that evaluate to zero length after rasterization will be
culled if
VkPhysicalDeviceConservativeRasterizationPropertiesEXT::degenerateLinesRasterized
is VK_FALSE or will generate fragments if
degenerateLinesRasterized is VK_TRUE.
The fragments input values for these degenerate lines take their attribute
and depth values from the provoking vertex.
Lines that are zero length before rasterization may be culled regardless.
For points if VK_CONSERVATIVE_RASTERIZATION_MODE_OVERESTIMATE_EXT is
enabled, and the implementation sets
VkPhysicalDeviceConservativeRasterizationPropertiesEXT::conservativePointAndLineRasterization
to VK_TRUE, fragments will be generated if the point square covers any
portion of the pixel square, including its edges or corners.
When underestimate conservative rasterization is enabled, rather than
evaluating coverage at individual sample locations, a determination is made
of whether all of the pixel (including its edges and corners) is covered by
the primitive.
If the entire pixel is covered, then a fragment is generated with all bits
of its coverage sample mask enabled, otherwise the fragment is discarded
even if some portion of the pixel is covered.
If the implementation supports
VkPhysicalDeviceConservativeRasterizationPropertiesEXT::conservativeRasterizationPostDepthCoverage
and the
PostDepthCoverage
execution mode is specified the SampleMask built-in input variable will
reflect the coverage after the early per-fragment depth and stencil tests
are applied.
For triangles, if VK_CONSERVATIVE_RASTERIZATION_MODE_UNDERESTIMATE_EXT
is enabled, fragments will only be generated if they are fully covered by
the generating primitive, including its edges and corners.
For lines, if VK_CONSERVATIVE_RASTERIZATION_MODE_UNDERESTIMATE_EXT is
enabled, fragments will be generated if the entire pixel, including its
edges and corners is covered by the line.
For points, if VK_CONSERVATIVE_RASTERIZATION_MODE_UNDERESTIMATE_EXT is
enabled, fragments will only be generated for pixel squares that are fully
covered by the point square.
For both overestimate and underestimate conservative rasterization modes a
pixel square that is fully covered by the generating primitive must set
FullyCoveredEXT to VK_TRUE if the implementation enables the
VkPhysicalDeviceConservativeRasterizationPropertiesEXT::fullyCoveredFragmentShaderInputVariable
feature.
25. Fragment Operations
Fragment operations execute on a per-fragment or per-sample basis, affecting whether or how a fragment or sample is written to the framebuffer. Some operations execute before fragment shading, and others after. Fragment operations always adhere to rasterization order.
25.1. Early Per-Fragment Tests
Once fragments are produced by rasterization, a number of per-fragment operations are performed prior to fragment shader execution. If a fragment is discarded during any of these operations, it will not be processed by any subsequent stage, including fragment shader execution.
The scissor test and sample mask generation are both always performed during early fragment tests.
Fragment operations are performed in the following order:
-
the discard rectangles test (see Discard Rectangles Test)
-
the scissor test (see Scissor Test)
-
multisample fragment operations (see Sample Mask)
If early per-fragment operations are enabled by the fragment shader, these operations are also performed:
If post-depth coverage operation is
enabled by the fragment
shader, the SampleMask
coverage is determined after the early stencil and depth tests.
25.2. Discard Rectangles Test
The discard rectangles test determines if fragment’s framebuffer coordinates
(xf,yf) are inclusive or exclusive to a set of discard-space
rectangles.
The discard rectangles are set with the
VkPipelineDiscardRectangleStateCreateInfoEXT pipeline state, which is
defined as:
typedef struct VkPipelineDiscardRectangleStateCreateInfoEXT {
VkStructureType sType;
const void* pNext;
VkPipelineDiscardRectangleStateCreateFlagsEXT flags;
VkDiscardRectangleModeEXT discardRectangleMode;
uint32_t discardRectangleCount;
const VkRect2D* pDiscardRectangles;
} VkPipelineDiscardRectangleStateCreateInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
discardRectangleModeis the mode used to determine whether fragments that lie within the discard rectangle are discarded or not. -
discardRectangleCountis the number of discard rectangles used by the pipeline. -
pDiscardRectanglesis a pointer to an array of VkRect2D structures, defining the discard rectangles. If the discard rectangle state is dynamic, this member is ignored.
typedef VkFlags VkPipelineDiscardRectangleStateCreateFlagsEXT;
VkPipelineDiscardRectangleStateCreateFlagsEXT is a bitmask type for
setting a mask, but is currently reserved for future use.
The VkPipelineDiscardRectangleStateCreateInfoEXT state is set by
adding an instance of this structure to the pNext chain of an instance
of the VkGraphicsPipelineCreateInfo structure and setting the graphics
pipeline state with vkCreateGraphicsPipelines.
If the bound pipeline state object was not created with the
VK_DYNAMIC_STATE_DISCARD_RECTANGLE_EXT dynamic state enabled, discard
rectangles are specified using the pDiscardRectangles member of
VkPipelineDiscardRectangleStateCreateInfoEXT linked to the pipeline
state object.
If the pipeline state object was created with the
VK_DYNAMIC_STATE_DISCARD_RECTANGLE_EXT dynamic state enabled, the
discard rectangles are dynamically set and changed with the command:
void vkCmdSetDiscardRectangleEXT(
VkCommandBuffer commandBuffer,
uint32_t firstDiscardRectangle,
uint32_t discardRectangleCount,
const VkRect2D* pDiscardRectangles);
-
commandBufferis the command buffer into which the command will be recorded. -
firstDiscardRectangleis the index of the first discard rectangle whose state is updated by the command. -
discardRectangleCountis the number of discard rectangles whose state are updated by the command. -
pDiscardRectanglesis a pointer to an array of VkRect2D structures specifying discard rectangles.
The discard rectangle taken from element i of pDiscardRectangles
replace the current state for the discard rectangle index
firstDiscardRectangle + i, for i in [0,
discardRectangleCount).
The VkOffset2D::x and VkOffset2D::y values of the
discard rectangle VkRect2D specify the upper-left origin of the
discard rectangle box.
The lower-right corner of the discard rectangle box is specified as the
VkExtent2D::width and VkExtent2D::height from the
upper-left origin.
If offset.x ≤ xf < offset.x +
extent.width and offset.y ≤ yf < offset.y
+ extent.height for the selected discard rectangle, then the
fragment is within the discard rectangle box.
When the discard rectangle mode is
VK_DISCARD_RECTANGLE_MODE_INCLUSIVE_EXT a fragment within at least one
of the active discard rectangle boxes passes the discard rectangle test;
otherwise the fragment fails the discard rectangle test and is discarded.
When the discard rectangle mode is
VK_DISCARD_RECTANGLE_MODE_EXCLUSIVE_EXT a fragment within at least one
of the active discard rectangle boxes fails the discard rectangle test, and
the fragment is discarded; otherwise the fragment passes the discard
rectangles test.
The discard rectangles test only applies to drawing commands,
not to other commands like clears or copies.
Possible values of
VkPipelineDiscardRectangleStateCreateInfoEXT::discardRectangleMode,
specifying the behavior of the discard rectangle test, are:
typedef enum VkDiscardRectangleModeEXT {
VK_DISCARD_RECTANGLE_MODE_INCLUSIVE_EXT = 0,
VK_DISCARD_RECTANGLE_MODE_EXCLUSIVE_EXT = 1,
} VkDiscardRectangleModeEXT;
-
VK_DISCARD_RECTANGLE_MODE_INCLUSIVE_EXTspecifies that a fragment within any discard rectangle satisfies the test. -
VK_DISCARD_RECTANGLE_MODE_EXCLUSIVE_EXTspecifies that a fragment not within any of the discard rectangles satisfies the test.
25.3. Scissor Test
The scissor test determines if a fragment’s framebuffer coordinates
(xf,yf) lie within the scissor rectangle corresponding to the
viewport index (see Controlling the Viewport)
used by the primitive that generated the fragment.
If the pipeline state object is created without
VK_DYNAMIC_STATE_SCISSOR enabled then the scissor rectangles are set
by the VkPipelineViewportStateCreateInfo state of the pipeline state
object.
Otherwise, to dynamically set the scissor rectangles call:
void vkCmdSetScissor(
VkCommandBuffer commandBuffer,
uint32_t firstScissor,
uint32_t scissorCount,
const VkRect2D* pScissors);
-
commandBufferis the command buffer into which the command will be recorded. -
firstScissoris the index of the first scissor whose state is updated by the command. -
scissorCountis the number of scissors whose rectangles are updated by the command. -
pScissorsis a pointer to an array of VkRect2D structures defining scissor rectangles.
The scissor rectangles taken from element i of pScissors replace
the current state for the scissor index firstScissor + i,
for i in [0, scissorCount).
Each scissor rectangle is described by a VkRect2D structure, with the
offset.x and offset.y values determining the upper left corner
of the scissor rectangle, and the extent.width and extent.height
values determining the size in pixels.
If offset.x ≤ xf < offset.x +
extent.width and offset.y ≤ yf < offset.y
+ extent.height for the selected scissor rectangle, then the
scissor test passes.
Otherwise, the test fails and the fragment is discarded.
For points, lines, and polygons, the scissor rectangle for a primitive is
selected in the same manner as the viewport (see
Controlling the Viewport).
The scissor rectangles test only applies to drawing commands,
not to other commands like clears or copies.
It is legal for offset.x + extent.width or
offset.y + extent.height to exceed the dimensions of
the framebuffer - the scissor test still applies as defined above.
Rasterization does not produce fragments outside of the framebuffer, so such
fragments never have the scissor test performed on them.
The scissor test is always performed. Applications can effectively disable the scissor test by specifying a scissor rectangle that encompasses the entire framebuffer.
25.4. Sample Mask
This step modifies fragment coverage values based on the values in the
pSampleMask array member of
VkPipelineMultisampleStateCreateInfo, as described previously in
section Graphics Pipelines.
pSampleMask contains an array of static coverage information that is
ANDed with the coverage information generated during rasterization.
Bits that are zero disable coverage for the corresponding sample.
Bit B of mask word M corresponds to sample 32 × M
+ B.
The array is sized to a length of ⌈ rasterizationSamples /
32 ⌉ words.
If pSampleMask is NULL, it is treated as if the mask has all bits
enabled, i.e. no coverage is removed from fragments.
The elements of the sample mask array are of type VkSampleMask,
each representing 32 bits of coverage information:
typedef uint32_t VkSampleMask;
25.5. Early Fragment Test Mode
The depth bounds test, stencil test, depth test, and occlusion query sample counting are performed before fragment shading if and only if early fragment tests are enabled by the fragment shader (see Early Fragment Tests). When early per-fragment operations are enabled, these operations are performed prior to fragment shader execution, and the stencil buffer, depth buffer, and occlusion query sample counts will be updated accordingly; these operations will not be performed again after fragment shader execution.
If a pipeline’s fragment shader has early fragment tests disabled, these operations are performed only after fragment program execution, in the order described below. If a pipeline does not contain a fragment shader, these operations are performed only once.
If early fragment tests are enabled, any depth value computed by the fragment shader has no effect. Additionally, the depth test (including depth writes), stencil test (including stencil writes) and sample counting operations are performed even for fragments or samples that would be discarded after fragment shader execution due to per-fragment operations such as alpha-to-coverage tests, or due to the fragment being discarded by the shader itself.
25.6. Late Per-Fragment Tests
After programmable fragment processing, per-fragment operations are performed before blending and color output to the framebuffer.
A fragment is produced by rasterization with framebuffer coordinates of (xf,yf) and depth z, as described in Rasterization. The fragment is then modified by programmable fragment processing, which adds associated data as described in Shaders. The fragment is then further modified, and possibly discarded by the late per-fragment operations described in this chapter. Finally, if the fragment was not discarded, it is used to update the framebuffer at the fragment’s framebuffer coordinates for any samples that remain covered.
The depth bounds test, stencil test, and depth test are performed for each pixel sample, rather than just once for each fragment. Stencil and depth operations are performed for a pixel sample only if that sample’s fragment coverage bit is a value of 1 when the fragment executes the corresponding stage of the graphics pipeline. If the corresponding coverage bit is 0, no operations are performed for that sample. Failure of the depth bounds, stencil, or depth test results in termination of the processing of that sample by means of disabling coverage for that sample, rather than discarding of the fragment. If, at any point, a fragment’s coverage becomes zero for all samples, then the fragment is discarded. All operations are performed on the depth and stencil values stored in the depth/stencil attachment of the framebuffer. The contents of the color attachments are not modified at this point.
The depth bounds test, stencil test, depth test, and occlusion query operations described in Depth Bounds Test, Stencil Test, Depth Test, Sample Counting are instead performed prior to fragment processing, as described in Early Fragment Test Mode, if requested by the fragment shader.
25.7. Mixed attachment samples
Special rules apply to per-fragment operations when the number of samples of the color attachments differs from the number of samples of the depth/stencil attachment used in a subpass.
Let C be the number of color attachment samples and D be the number of depth/stencil attachment samples used by a given subpass.
If C < D then only the first C number of samples are guaranteed
to have a corresponding fragment shader invocation and thus a corresponding
color output value, unless the fragment shaders produce inputs to the late
per-fragment tests (e.g. by outputting to a variable decorated with the
FragDepth built-in decoration).
Implementations are allowed to produce fragment shader invocations for
samples with indices greater than or equal to C but (other than
potential side effects) the color outputs of fragment shader invocations
corresponding to such samples are discarded.
25.8. Multisample Coverage
If a fragment shader is active and its entry point’s interface includes a
built-in output variable decorated with SampleMask and also decorated
with OverrideCoverageNV the fragment coverage is replaced with the
sample mask bits set in the shader.
Otherwise if the built-in output variable decorated with SampleMask is
not also decorated with OverrideCoverageNV then the fragment coverage
is ANDed with the bits of the sample mask to generate a new fragment
coverage value.
If such a fragment shader did not assign a value to SampleMask due to
flow of control, the value ANDed with the fragment coverage is
undefined.
If no fragment shader is active, or if the active fragment shader does not
include SampleMask in its interface, the fragment coverage is not
modified.
Next, the fragment alpha and coverage values are modified based on the
alphaToCoverageEnable and alphaToOneEnable members of the
VkPipelineMultisampleStateCreateInfo structure.
All alpha values in this section refer only to the alpha component of the
fragment shader output that has a Location and Index decoration of
zero (see the Fragment Output Interface
section).
If that shader output has an integer or unsigned integer type, then these
operations are skipped.
If alphaToCoverageEnable is enabled, a temporary coverage value with
rasterizationSamples bits is generated where each bit is determined by
the fragment’s alpha value.
The temporary coverage value is then ANDed with the fragment coverage value
to generate a new fragment coverage value.
No specific algorithm is specified for converting the alpha value to a temporary coverage mask. It is intended that the number of 1’s in this value be proportional to the alpha value (clamped to [0,1]), with all 1’s corresponding to a value of 1.0 and all 0’s corresponding to 0.0. The algorithm may be different at different pixel locations.
|
Note
Using different algorithms at different pixel location may help to avoid artifacts caused by regular coverage sample locations. |
Next, if alphaToOneEnable is enabled, each alpha value is replaced by
the maximum representable alpha value for fixed-point color buffers, or by
1.0 for floating-point buffers.
Otherwise, the alpha values are not changed.
25.9. Depth and Stencil Operations
Pipeline state controlling the depth bounds tests,
stencil test, and depth test is
specified through the members of the
VkPipelineDepthStencilStateCreateInfo structure.
The VkPipelineDepthStencilStateCreateInfo structure is defined as:
typedef struct VkPipelineDepthStencilStateCreateInfo {
VkStructureType sType;
const void* pNext;
VkPipelineDepthStencilStateCreateFlags flags;
VkBool32 depthTestEnable;
VkBool32 depthWriteEnable;
VkCompareOp depthCompareOp;
VkBool32 depthBoundsTestEnable;
VkBool32 stencilTestEnable;
VkStencilOpState front;
VkStencilOpState back;
float minDepthBounds;
float maxDepthBounds;
} VkPipelineDepthStencilStateCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
depthTestEnablecontrols whether depth testing is enabled. -
depthWriteEnablecontrols whether depth writes are enabled whendepthTestEnableisVK_TRUE. Depth writes are always disabled whendepthTestEnableisVK_FALSE. -
depthCompareOpis the comparison operator used in the depth test. -
depthBoundsTestEnablecontrols whether depth bounds testing is enabled. -
stencilTestEnablecontrols whether stencil testing is enabled. -
frontandbackcontrol the parameters of the stencil test. -
minDepthBoundsandmaxDepthBoundsdefine the range of values used in the depth bounds test.
typedef VkFlags VkPipelineDepthStencilStateCreateFlags;
VkPipelineDepthStencilStateCreateFlags is a bitmask type for setting a
mask, but is currently reserved for future use.
25.10. Depth Bounds Test
The depth bounds test conditionally disables coverage of a sample based on
the outcome of a comparison between the value za in the depth
attachment at location (xf,yf) (for the appropriate sample) and a
range of values.
The test is enabled or disabled by the depthBoundsTestEnable member of
VkPipelineDepthStencilStateCreateInfo: If the pipeline state object is
created without the VK_DYNAMIC_STATE_DEPTH_BOUNDS dynamic state
enabled then the range of values used in the depth bounds test are defined
by the minDepthBounds and maxDepthBounds members of the
VkPipelineDepthStencilStateCreateInfo structure.
Otherwise, to dynamically set the depth bounds range values call:
void vkCmdSetDepthBounds(
VkCommandBuffer commandBuffer,
float minDepthBounds,
float maxDepthBounds);
-
commandBufferis the command buffer into which the command will be recorded. -
minDepthBoundsis the lower bound of the range of depth values used in the depth bounds test. -
maxDepthBoundsis the upper bound of the range.
If minDepthBounds ≤ za ≤ maxDepthBounds}, then
the depth bounds test passes.
Otherwise, the test fails and the sample’s coverage bit is cleared in the
fragment.
If there is no depth framebuffer attachment or if the depth bounds test is
disabled, it is as if the depth bounds test always passes.
25.11. Stencil Test
The stencil test conditionally disables coverage of a sample based on the
outcome of a comparison between the stencil value in the depth/stencil
attachment at location (xf,yf) (for the appropriate sample) and a
reference value.
The stencil test also updates the value in the stencil attachment, depending
on the test state, the stencil value and the stencil write masks.
The test is enabled or disabled by the stencilTestEnable member of
VkPipelineDepthStencilStateCreateInfo.
When disabled, the stencil test and associated modifications are not made, and the sample’s coverage is not modified.
The stencil test is controlled with the front and back members
of VkPipelineDepthStencilStateCreateInfo which are of type
VkStencilOpState.
The VkStencilOpState structure is defined as:
typedef struct VkStencilOpState {
VkStencilOp failOp;
VkStencilOp passOp;
VkStencilOp depthFailOp;
VkCompareOp compareOp;
uint32_t compareMask;
uint32_t writeMask;
uint32_t reference;
} VkStencilOpState;
-
failOpis a VkStencilOp value specifying the action performed on samples that fail the stencil test. -
passOpis a VkStencilOp value specifying the action performed on samples that pass both the depth and stencil tests. -
depthFailOpis a VkStencilOp value specifying the action performed on samples that pass the stencil test and fail the depth test. -
compareOpis a VkCompareOp value specifying the comparison operator used in the stencil test. -
compareMaskselects the bits of the unsigned integer stencil values participating in the stencil test. -
writeMaskselects the bits of the unsigned integer stencil values updated by the stencil test in the stencil framebuffer attachment. -
referenceis an integer reference value that is used in the unsigned stencil comparison.
There are two sets of stencil-related state, the front stencil state set and the back stencil state set. Stencil tests and writes use the front set of stencil state when processing front-facing fragments and use the back set of stencil state when processing back-facing fragments. Fragments rasterized from non-polygon primitives (points and lines) are always considered front-facing. Fragments rasterized from polygon primitives inherit their facingness from the polygon, even if the polygon is rasterized as points or lines due to the current VkPolygonMode. Whether a polygon is front- or back-facing is determined in the same manner used for face culling (see Basic Polygon Rasterization).
The operation of the stencil test is also affected by the compareMask,
writeMask, and reference members of VkStencilOpState set
in the pipeline state object if the pipeline state object is created without
the VK_DYNAMIC_STATE_STENCIL_COMPARE_MASK,
VK_DYNAMIC_STATE_STENCIL_WRITE_MASK, and
VK_DYNAMIC_STATE_STENCIL_REFERENCE dynamic states enabled,
respectively.
If the pipeline state object is created with the
VK_DYNAMIC_STATE_STENCIL_COMPARE_MASK dynamic state enabled, then to
dynamically set the stencil compare mask call:
void vkCmdSetStencilCompareMask(
VkCommandBuffer commandBuffer,
VkStencilFaceFlags faceMask,
uint32_t compareMask);
-
commandBufferis the command buffer into which the command will be recorded. -
faceMaskis a bitmask of VkStencilFaceFlagBits specifying the set of stencil state for which to update the compare mask. -
compareMaskis the new value to use as the stencil compare mask.
Bits which can be set in the
vkCmdSetStencilCompareMask::faceMask parameter, and similar
parameters of other commands specifying which stencil state to update
stencil masks for, are:
typedef enum VkStencilFaceFlagBits {
VK_STENCIL_FACE_FRONT_BIT = 0x00000001,
VK_STENCIL_FACE_BACK_BIT = 0x00000002,
VK_STENCIL_FRONT_AND_BACK = 0x00000003,
} VkStencilFaceFlagBits;
-
VK_STENCIL_FACE_FRONT_BITspecifies that only the front set of stencil state is updated. -
VK_STENCIL_FACE_BACK_BITspecifies that only the back set of stencil state is updated. -
VK_STENCIL_FRONT_AND_BACKis the combination ofVK_STENCIL_FACE_FRONT_BITandVK_STENCIL_FACE_BACK_BIT, and specifies that both sets of stencil state are updated.
typedef VkFlags VkStencilFaceFlags;
VkStencilFaceFlags is a bitmask type for setting a mask of zero or
more VkStencilFaceFlagBits.
If the pipeline state object is created with the
VK_DYNAMIC_STATE_STENCIL_WRITE_MASK dynamic state enabled, then to
dynamically set the stencil write mask call:
void vkCmdSetStencilWriteMask(
VkCommandBuffer commandBuffer,
VkStencilFaceFlags faceMask,
uint32_t writeMask);
-
commandBufferis the command buffer into which the command will be recorded. -
faceMaskis a bitmask of VkStencilFaceFlagBits specifying the set of stencil state for which to update the write mask, as described above for vkCmdSetStencilCompareMask. -
writeMaskis the new value to use as the stencil write mask.
If the pipeline state object is created with the
VK_DYNAMIC_STATE_STENCIL_REFERENCE dynamic state enabled, then to
dynamically set the stencil reference value call:
void vkCmdSetStencilReference(
VkCommandBuffer commandBuffer,
VkStencilFaceFlags faceMask,
uint32_t reference);
-
commandBufferis the command buffer into which the command will be recorded. -
faceMaskis a bitmask of VkStencilFaceFlagBits specifying the set of stencil state for which to update the reference value, as described above for vkCmdSetStencilCompareMask. -
referenceis the new value to use as the stencil reference value.
reference is an integer reference value that is used in the unsigned
stencil comparison.
The reference value used by stencil comparison must be within the range
[0,2s-1] , where s is the number of bits in the stencil
framebuffer attachment, otherwise the reference value is considered
undefined.
The s least significant bits of compareMask are bitwise
ANDed with both the reference and the stored stencil value, and the
resulting masked values are those that participate in the comparison
controlled by compareOp.
Let R be the masked reference value and S be the masked stored
stencil value.
Possible values of VkStencilOpState::compareOp, specifying the stencil
comparison function, are:
typedef enum VkCompareOp {
VK_COMPARE_OP_NEVER = 0,
VK_COMPARE_OP_LESS = 1,
VK_COMPARE_OP_EQUAL = 2,
VK_COMPARE_OP_LESS_OR_EQUAL = 3,
VK_COMPARE_OP_GREATER = 4,
VK_COMPARE_OP_NOT_EQUAL = 5,
VK_COMPARE_OP_GREATER_OR_EQUAL = 6,
VK_COMPARE_OP_ALWAYS = 7,
} VkCompareOp;
-
VK_COMPARE_OP_NEVERspecifies that the test never passes. -
VK_COMPARE_OP_LESSspecifies that the test passes when R < S. -
VK_COMPARE_OP_EQUALspecifies that the test passes when R = S. -
VK_COMPARE_OP_LESS_OR_EQUALspecifies that the test passes when R ≤ S. -
VK_COMPARE_OP_GREATERspecifies that the test passes when R > S. -
VK_COMPARE_OP_NOT_EQUALspecifies that the test passes when R ≠ S. -
VK_COMPARE_OP_GREATER_OR_EQUALspecifies that the test passes when R ≥ S. -
VK_COMPARE_OP_ALWAYSspecifies that the test always passes.
Possible values of the failOp, passOp, and depthFailOp
members of VkStencilOpState, specifying what happens to the stored
stencil value if this or certain subsequent tests fail or pass, are:
typedef enum VkStencilOp {
VK_STENCIL_OP_KEEP = 0,
VK_STENCIL_OP_ZERO = 1,
VK_STENCIL_OP_REPLACE = 2,
VK_STENCIL_OP_INCREMENT_AND_CLAMP = 3,
VK_STENCIL_OP_DECREMENT_AND_CLAMP = 4,
VK_STENCIL_OP_INVERT = 5,
VK_STENCIL_OP_INCREMENT_AND_WRAP = 6,
VK_STENCIL_OP_DECREMENT_AND_WRAP = 7,
} VkStencilOp;
-
VK_STENCIL_OP_KEEPkeeps the current value. -
VK_STENCIL_OP_ZEROsets the value to 0. -
VK_STENCIL_OP_REPLACEsets the value toreference. -
VK_STENCIL_OP_INCREMENT_AND_CLAMPincrements the current value and clamps to the maximum representable unsigned value. -
VK_STENCIL_OP_DECREMENT_AND_CLAMPdecrements the current value and clamps to 0. -
VK_STENCIL_OP_INVERTbitwise-inverts the current value. -
VK_STENCIL_OP_INCREMENT_AND_WRAPincrements the current value and wraps to 0 when the maximum value would have been exceeded. -
VK_STENCIL_OP_DECREMENT_AND_WRAPdecrements the current value and wraps to the maximum possible value when the value would go below 0.
For purposes of increment and decrement, the stencil bits are considered as an unsigned integer.
If the stencil test fails, the sample’s coverage bit is cleared in the fragment. If there is no stencil framebuffer attachment, stencil modification cannot occur, and it is as if the stencil tests always pass.
If the stencil test passes, the writeMask member of the
VkStencilOpState structures controls how the updated stencil value is
written to the stencil framebuffer attachment.
The least significant s bits of writeMask, where s is the
number of bits in the stencil framebuffer attachment, specify an integer
mask.
Where a 1 appears in this mask, the corresponding bit in the stencil
value in the depth/stencil attachment is written; where a 0 appears,
the bit is not written.
The writeMask value uses either the front-facing or back-facing state
based on the facingness of the fragment.
Fragments generated by front-facing primitives use the front mask and
fragments generated by back-facing primitives use the back mask.
25.12. Depth Test
The depth test conditionally disables coverage of a sample based on the
outcome of a comparison between the fragment’s depth value at the sample
location and the sample’s depth value in the depth/stencil attachment at
location (xf,yf).
The comparison is enabled or disabled with the depthTestEnable member
of the VkPipelineDepthStencilStateCreateInfo structure.
When disabled, the depth comparison and subsequent possible updates to the
value of the depth component of the depth/stencil attachment are bypassed
and the fragment is passed to the next operation.
The stencil value, however, can be modified as indicated above as if the
depth test passed.
If enabled, the comparison takes place and the depth/stencil attachment
value can subsequently be modified.
The comparison is specified with the depthCompareOp member of
VkPipelineDepthStencilStateCreateInfo.
Let zf be the incoming fragment’s depth value for a sample,
and let za be the depth/stencil attachment value in memory for that
sample.
The depth test passes under the following conditions:
-
VK_COMPARE_OP_NEVER: the test never passes. -
VK_COMPARE_OP_LESS: the test passes when zf < za. -
VK_COMPARE_OP_EQUAL: the test passes when zf = za. -
VK_COMPARE_OP_LESS_OR_EQUAL: the test passes when zf ≤ za. -
VK_COMPARE_OP_GREATER: the test passes when zf > za. -
VK_COMPARE_OP_NOT_EQUAL: the test passes when zf ≠ za. -
VK_COMPARE_OP_GREATER_OR_EQUAL: the test passes when zf ≥ za. -
VK_COMPARE_OP_ALWAYS: the test always passes.
If VkPipelineRasterizationStateCreateInfo::depthClampEnable is
enabled, before the incoming fragment’s zf is compared to
za, zf is clamped to [min(n,f),max(n,f)],
where n and f are the minDepth and maxDepth depth
range values of the viewport used by this fragment, respectively.
If the depth test fails, the sample’s coverage bit is cleared in the fragment. The stencil value at the sample’s location is updated according to the function currently in effect for depth test failure.
If the depth test passes, the sample’s (possibly clamped) zf
value is conditionally written to the depth framebuffer attachment based on
the depthWriteEnable member of
VkPipelineDepthStencilStateCreateInfo.
If depthWriteEnable is VK_TRUE the value is written, and if it
is VK_FALSE the value is not written.
If the depth framebuffer attachment is a fixed-point format and the depth
value is outside of the 0.0 to 1.0 range the depth value is clamped
between 0.0 and 1.0 inclusive before writing.
The stencil value at the sample’s location is updated according to the
function currently in effect for depth test success.
If there is no depth framebuffer attachment, it is as if the depth test always passes.
25.13. Sample Counting
Occlusion queries use query pool entries to track the number of samples that pass all the per-fragment tests. The mechanism of collecting an occlusion query value is described in Occlusion Queries.
The occlusion query sample counter increments by one for each sample with a coverage value of 1 in each fragment that survives all the per-fragment tests, including scissor, sample mask, alpha to coverage, stencil, and depth tests.
25.14. Fragment Coverage To Color
If the pNext chain of VkPipelineMultisampleStateCreateInfo
includes a VkPipelineCoverageToColorStateCreateInfoNV structure, then
that structure controls whether the fragment coverage is substituted for a
fragment color output and, if so, which output is replaced.
The VkPipelineCoverageToColorStateCreateInfoNV structure is defined
as:
typedef struct VkPipelineCoverageToColorStateCreateInfoNV {
VkStructureType sType;
const void* pNext;
VkPipelineCoverageToColorStateCreateFlagsNV flags;
VkBool32 coverageToColorEnable;
uint32_t coverageToColorLocation;
} VkPipelineCoverageToColorStateCreateInfoNV;
-
sTypeis the type of this structure -
pNextisNULLor a pointer to an extension-specific structure -
flagsis reserved for future use. -
coverageToColorEnablecontrols whether the fragment coverage value replaces a fragment color output. -
coverageToColorLocationcontrols which fragment shader color output value is replaced.
If coverageToColorEnable is VK_TRUE, the fragment coverage
information is treated as a bitmask with one bit for each sample (as in the
Sample Mask section), and this bitmask replaces the
first component of the color value corresponding to the fragment shader
output location with Location equal to coverageToColorLocation
and Index equal to zero.
If the color attachment format has fewer bits than the sample coverage, the
low bits of the sample coverage bitmask are taken without any clamping.
If the color attachment format has more bits than the sample coverage, the
high bits of the sample coverage bitmask are filled with zeros.
If Sample Shading is in use, the coverage bitmask only has bits set for samples that correspond to the fragment shader invocation that shades those samples.
This pipeline stage occurs after sample counting and before blending, and is
always performed after fragment shading regardless of the setting of
EarlyFragmentTests.
If coverageToColorEnable is VK_FALSE, these operations are
skipped.
If this structure is not present, it is as if coverageToColorEnable is
VK_FALSE.
typedef VkFlags VkPipelineCoverageToColorStateCreateFlagsNV;
VkPipelineCoverageToColorStateCreateFlagsNV is a bitmask type for
setting a mask, but is currently reserved for future use.
25.15. Coverage Reduction
Coverage reduction generates a color sample mask from the coverage mask, with one bit for each sample in the color attachment(s) for the subpass. If a bit in the color sample mask is 0, then blending and writing to the framebuffer are not performed for that sample.
If the pipeline’s
VkPipelineMultisampleStateCreateInfo::rasterizationSamples is
greater than one and the VkAttachmentDescription::samples of the
color attachments is one, then the fragment’s coverage is reduced from
rasterizationSamples bits to a single bit, where the color sample mask
is 1 if any bit in the fragment’s coverage is on, and 0 otherwise.
If the pipeline’s
VkPipelineMultisampleStateCreateInfo::rasterizationSamples is
greater than the VkAttachmentDescription::samples of the color
attachments in the subpass, then the fragment’s coverage is reduced from
rasterizationSamples bits to a color sample mask with
VkAttachmentDescription::samples bits.
There is an implementation-dependent association of raster samples to color
samples.
The reduced color sample mask is computed such that the bit for each color
sample is 1 if any of the associated bits in the fragment’s coverage is on,
and 0 otherwise.
25.15.1. Coverage Modulation
As part of coverage reduction, fragment color values can also be modulated (multiplied) by a value that is a function of fraction of covered rasterization samples associated with that color sample.
Pipeline state controlling coverage reduction is specified through the
members of the VkPipelineCoverageModulationStateCreateInfoNV
structure.
The VkPipelineCoverageModulationStateCreateInfoNV structure is defined
as:
typedef struct VkPipelineCoverageModulationStateCreateInfoNV {
VkStructureType sType;
const void* pNext;
VkPipelineCoverageModulationStateCreateFlagsNV flags;
VkCoverageModulationModeNV coverageModulationMode;
VkBool32 coverageModulationTableEnable;
uint32_t coverageModulationTableCount;
const float* pCoverageModulationTable;
} VkPipelineCoverageModulationStateCreateInfoNV;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
coverageModulationModecontrols which color components are modulated and is of type VkCoverageModulationModeNV. -
coverageModulationTableEnablecontrols whether the modulation factor is looked up from a table inpCoverageModulationTable. -
coverageModulationTableCountis the number of elements inpCoverageModulationTable. -
pCoverageModulationTableis a table of modulation factors containing a value for each number of covered samples.
If coverageModulationTableEnable is VK_FALSE, then for each
color sample the associated bits of the fragment’s coverage are counted and
divided by the number of associated bits to produce a modulation factor
R in the range (0,1] (a value of zero would have been killed due
to a color coverage of 0).
Specifically:
-
N = value of
rasterizationSamples -
M = value of VkAttachmentDescription::
samplesfor any color attachments -
R = popcount(associated coverage bits) / (N / M)
If coverageModulationTableEnable is VK_TRUE, the value R
is computed using a programmable lookup table.
The lookup table has N / M elements, and the element of the table is
selected by:
-
R =
pCoverageModulationTable[popcount(associated coverage bits)-1]
Note that the table does not have an entry for popcount(associated coverage bits) = 0, because such samples would have been killed.
The values of pCoverageModulationTable may be rounded to an
implementation-dependent precision, which is at least as fine as 1 /
N, and clamped to [0,1].
For each color attachment with a floating point or normalized color format,
each fragment output color value is replicated to M values which can
each be modulated (multiplied) by that color sample’s associated value of
R.
Which components are modulated is controlled by
coverageModulationMode.
If this structure is not present, it is as if coverageModulationMode is
VK_COVERAGE_MODULATION_MODE_NONE_NV.
typedef VkFlags VkPipelineCoverageModulationStateCreateFlagsNV;
VkPipelineCoverageModulationStateCreateFlagsNV is a bitmask type for
setting a mask, but is currently reserved for future use.
Possible values of
VkPipelineCoverageModulationStateCreateInfoNV::coverageModulationMode,
specifying which color components are modulated, are:
typedef enum VkCoverageModulationModeNV {
VK_COVERAGE_MODULATION_MODE_NONE_NV = 0,
VK_COVERAGE_MODULATION_MODE_RGB_NV = 1,
VK_COVERAGE_MODULATION_MODE_ALPHA_NV = 2,
VK_COVERAGE_MODULATION_MODE_RGBA_NV = 3,
} VkCoverageModulationModeNV;
-
VK_COVERAGE_MODULATION_MODE_NONE_NVspecifies that no components are multiplied by the modulation factor. -
VK_COVERAGE_MODULATION_MODE_RGB_NVspecifies that the red, green, and blue components are multiplied by the modulation factor. -
VK_COVERAGE_MODULATION_MODE_ALPHA_NVspecifies that the alpha component is multiplied by the modulation factor. -
VK_COVERAGE_MODULATION_MODE_RGBA_NVspecifies that all components are multiplied by the modulation factor.
26. The Framebuffer
26.1. Blending
Blending combines the incoming source fragment’s R, G, B, and A values with the destination R, G, B, and A values of each sample stored in the framebuffer at the fragment’s (xf,yf) location. Blending is performed for each pixel sample, rather than just once for each fragment.
Source and destination values are combined according to the blend operation, quadruplets of source and destination weighting factors determined by the blend factors, and a blend constant, to obtain a new set of R, G, B, and A values, as described below.
Blending is computed and applied separately to each color attachment used by the subpass, with separate controls for each attachment.
Prior to performing the blend operation, signed and unsigned normalized fixed-point color components undergo an implied conversion to floating-point as specified by Conversion from Normalized Fixed-Point to Floating-Point. Blending computations are treated as if carried out in floating-point, and basic blend operations are performed with a precision and dynamic range no lower than that used to represent destination components. Advanced blending operations are performed with a precision and dynamic range no lower than the smaller of that used to represent destination components or that used to represent 16-bit floating-point values.
Blending applies only to fixed-point and floating-point color attachments. If the color attachment has an integer format, blending is not applied.
The pipeline blend state is included in the
VkPipelineColorBlendStateCreateInfo structure during graphics pipeline
creation:
The VkPipelineColorBlendStateCreateInfo structure is defined as:
typedef struct VkPipelineColorBlendStateCreateInfo {
VkStructureType sType;
const void* pNext;
VkPipelineColorBlendStateCreateFlags flags;
VkBool32 logicOpEnable;
VkLogicOp logicOp;
uint32_t attachmentCount;
const VkPipelineColorBlendAttachmentState* pAttachments;
float blendConstants[4];
} VkPipelineColorBlendStateCreateInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
logicOpEnablecontrols whether to apply Logical Operations. -
logicOpselects which logical operation to apply. -
attachmentCountis the number ofVkPipelineColorBlendAttachmentStateelements inpAttachments. This value must equal thecolorAttachmentCountfor the subpass in which this pipeline is used. -
pAttachments: is a pointer to array of per target attachment states. -
blendConstantsis an array of four values used as the R, G, B, and A components of the blend constant that are used in blending, depending on the blend factor.
Each element of the pAttachments array is a
VkPipelineColorBlendAttachmentState structure specifying per-target
blending state for each individual color attachment.
If the independent blending feature
is not enabled on the device, all VkPipelineColorBlendAttachmentState
elements in the pAttachments array must be identical.
typedef VkFlags VkPipelineColorBlendStateCreateFlags;
VkPipelineColorBlendStateCreateFlags is a bitmask type for setting a
mask, but is currently reserved for future use.
The VkPipelineColorBlendAttachmentState structure is defined as:
typedef struct VkPipelineColorBlendAttachmentState {
VkBool32 blendEnable;
VkBlendFactor srcColorBlendFactor;
VkBlendFactor dstColorBlendFactor;
VkBlendOp colorBlendOp;
VkBlendFactor srcAlphaBlendFactor;
VkBlendFactor dstAlphaBlendFactor;
VkBlendOp alphaBlendOp;
VkColorComponentFlags colorWriteMask;
} VkPipelineColorBlendAttachmentState;
-
blendEnablecontrols whether blending is enabled for the corresponding color attachment. If blending is not enabled, the source fragment’s color for that attachment is passed through unmodified. -
srcColorBlendFactorselects which blend factor is used to determine the source factors (Sr,Sg,Sb). -
dstColorBlendFactorselects which blend factor is used to determine the destination factors (Dr,Dg,Db). -
colorBlendOpselects which blend operation is used to calculate the RGB values to write to the color attachment. -
srcAlphaBlendFactorselects which blend factor is used to determine the source factor Sa. -
dstAlphaBlendFactorselects which blend factor is used to determine the destination factor Da. -
alphaBlendOpselects which blend operation is use to calculate the alpha values to write to the color attachment. -
colorWriteMaskis a bitmask of VkColorComponentFlagBits specifying which of the R, G, B, and/or A components are enabled for writing, as described for the Color Write Mask.
26.1.1. Blend Factors
The source and destination color and alpha blending factors are selected from the enum:
typedef enum VkBlendFactor {
VK_BLEND_FACTOR_ZERO = 0,
VK_BLEND_FACTOR_ONE = 1,
VK_BLEND_FACTOR_SRC_COLOR = 2,
VK_BLEND_FACTOR_ONE_MINUS_SRC_COLOR = 3,
VK_BLEND_FACTOR_DST_COLOR = 4,
VK_BLEND_FACTOR_ONE_MINUS_DST_COLOR = 5,
VK_BLEND_FACTOR_SRC_ALPHA = 6,
VK_BLEND_FACTOR_ONE_MINUS_SRC_ALPHA = 7,
VK_BLEND_FACTOR_DST_ALPHA = 8,
VK_BLEND_FACTOR_ONE_MINUS_DST_ALPHA = 9,
VK_BLEND_FACTOR_CONSTANT_COLOR = 10,
VK_BLEND_FACTOR_ONE_MINUS_CONSTANT_COLOR = 11,
VK_BLEND_FACTOR_CONSTANT_ALPHA = 12,
VK_BLEND_FACTOR_ONE_MINUS_CONSTANT_ALPHA = 13,
VK_BLEND_FACTOR_SRC_ALPHA_SATURATE = 14,
VK_BLEND_FACTOR_SRC1_COLOR = 15,
VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR = 16,
VK_BLEND_FACTOR_SRC1_ALPHA = 17,
VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA = 18,
} VkBlendFactor;
The semantics of each enum value is described in the table below:
| VkBlendFactor | RGB Blend Factors (Sr,Sg,Sb) or (Dr,Dg,Db) | Alpha Blend Factor (Sa or Da) |
|---|---|---|
|
(0,0,0) |
0 |
|
(1,1,1) |
1 |
|
(Rs0,Gs0,Bs0) |
As0 |
|
(1-Rs0,1-Gs0,1-Bs0) |
1-As0 |
|
(Rd,Gd,Bd) |
Ad |
|
(1-Rd,1-Gd,1-Bd) |
1-Ad |
|
(As0,As0,As0) |
As0 |
|
(1-As0,1-As0,1-As0) |
1-As0 |
|
(Ad,Ad,Ad) |
Ad |
|
(1-Ad,1-Ad,1-Ad) |
1-Ad |
|
(Rc,Gc,Bc) |
Ac |
|
(1-Rc,1-Gc,1-Bc) |
1-Ac |
|
(Ac,Ac,Ac) |
Ac |
|
(1-Ac,1-Ac,1-Ac) |
1-Ac |
|
(f,f,f); f = min(As0,1-Ad) |
1 |
|
(Rs1,Gs1,Bs1) |
As1 |
|
(1-Rs1,1-Gs1,1-Bs1) |
1-As1 |
|
(As1,As1,As1) |
As1 |
|
(1-As1,1-As1,1-As1) |
1-As1 |
In this table, the following conventions are used:
-
Rs0,Gs0,Bs0 and As0 represent the first source color R, G, B, and A components, respectively, for the fragment output location corresponding to the color attachment being blended.
-
Rs1,Gs1,Bs1 and As1 represent the second source color R, G, B, and A components, respectively, used in dual source blending modes, for the fragment output location corresponding to the color attachment being blended.
-
Rd,Gd,Bd and Ad represent the R, G, B, and A components of the destination color. That is, the color currently in the corresponding color attachment for this fragment/sample.
-
Rc,Gc,Bc and Ac represent the blend constant R, G, B, and A components, respectively.
If the pipeline state object is created without the
VK_DYNAMIC_STATE_BLEND_CONSTANTS dynamic state enabled then the blend
constant (Rc,Gc,Bc,Ac) is specified via the
blendConstants member of VkPipelineColorBlendStateCreateInfo.
Otherwise, to dynamically set and change the blend constant, call:
void vkCmdSetBlendConstants(
VkCommandBuffer commandBuffer,
const float blendConstants[4]);
-
commandBufferis the command buffer into which the command will be recorded. -
blendConstantsis an array of four values specifying the R, G, B, and A components of the blend constant color used in blending, depending on the blend factor.
26.1.2. Dual-Source Blending
Blend factors that use the secondary color input
(Rs1,Gs1,Bs1,As1) (VK_BLEND_FACTOR_SRC1_COLOR,
VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR,
VK_BLEND_FACTOR_SRC1_ALPHA, and
VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA) may consume implementation
resources that could otherwise be used for rendering to multiple color
attachments.
Therefore, the number of color attachments that can be used in a
framebuffer may be lower when using dual-source blending.
Dual-source blending is only supported if the
dualSrcBlend feature is enabled.
The maximum number of color attachments that can be used in a subpass when
using dual-source blending functions is implementation-dependent and is
reported as the maxFragmentDualSrcAttachments member of
VkPhysicalDeviceLimits.
When using a fragment shader with dual-source blending functions, the color
outputs are bound to the first and second inputs of the blender using the
Index decoration, as described in Fragment
Output Interface.
If the second color input to the blender is not written in the shader, or if
no output is bound to the second input of a blender, the result of the
blending operation is not defined.
26.1.3. Blend Operations
Once the source and destination blend factors have been selected, they along with the source and destination components are passed to the blending operations. RGB and alpha components can use different operations. Possible values of VkBlendOp, specifying the operations, are:
typedef enum VkBlendOp {
VK_BLEND_OP_ADD = 0,
VK_BLEND_OP_SUBTRACT = 1,
VK_BLEND_OP_REVERSE_SUBTRACT = 2,
VK_BLEND_OP_MIN = 3,
VK_BLEND_OP_MAX = 4,
VK_BLEND_OP_ZERO_EXT = 1000148000,
VK_BLEND_OP_SRC_EXT = 1000148001,
VK_BLEND_OP_DST_EXT = 1000148002,
VK_BLEND_OP_SRC_OVER_EXT = 1000148003,
VK_BLEND_OP_DST_OVER_EXT = 1000148004,
VK_BLEND_OP_SRC_IN_EXT = 1000148005,
VK_BLEND_OP_DST_IN_EXT = 1000148006,
VK_BLEND_OP_SRC_OUT_EXT = 1000148007,
VK_BLEND_OP_DST_OUT_EXT = 1000148008,
VK_BLEND_OP_SRC_ATOP_EXT = 1000148009,
VK_BLEND_OP_DST_ATOP_EXT = 1000148010,
VK_BLEND_OP_XOR_EXT = 1000148011,
VK_BLEND_OP_MULTIPLY_EXT = 1000148012,
VK_BLEND_OP_SCREEN_EXT = 1000148013,
VK_BLEND_OP_OVERLAY_EXT = 1000148014,
VK_BLEND_OP_DARKEN_EXT = 1000148015,
VK_BLEND_OP_LIGHTEN_EXT = 1000148016,
VK_BLEND_OP_COLORDODGE_EXT = 1000148017,
VK_BLEND_OP_COLORBURN_EXT = 1000148018,
VK_BLEND_OP_HARDLIGHT_EXT = 1000148019,
VK_BLEND_OP_SOFTLIGHT_EXT = 1000148020,
VK_BLEND_OP_DIFFERENCE_EXT = 1000148021,
VK_BLEND_OP_EXCLUSION_EXT = 1000148022,
VK_BLEND_OP_INVERT_EXT = 1000148023,
VK_BLEND_OP_INVERT_RGB_EXT = 1000148024,
VK_BLEND_OP_LINEARDODGE_EXT = 1000148025,
VK_BLEND_OP_LINEARBURN_EXT = 1000148026,
VK_BLEND_OP_VIVIDLIGHT_EXT = 1000148027,
VK_BLEND_OP_LINEARLIGHT_EXT = 1000148028,
VK_BLEND_OP_PINLIGHT_EXT = 1000148029,
VK_BLEND_OP_HARDMIX_EXT = 1000148030,
VK_BLEND_OP_HSL_HUE_EXT = 1000148031,
VK_BLEND_OP_HSL_SATURATION_EXT = 1000148032,
VK_BLEND_OP_HSL_COLOR_EXT = 1000148033,
VK_BLEND_OP_HSL_LUMINOSITY_EXT = 1000148034,
VK_BLEND_OP_PLUS_EXT = 1000148035,
VK_BLEND_OP_PLUS_CLAMPED_EXT = 1000148036,
VK_BLEND_OP_PLUS_CLAMPED_ALPHA_EXT = 1000148037,
VK_BLEND_OP_PLUS_DARKER_EXT = 1000148038,
VK_BLEND_OP_MINUS_EXT = 1000148039,
VK_BLEND_OP_MINUS_CLAMPED_EXT = 1000148040,
VK_BLEND_OP_CONTRAST_EXT = 1000148041,
VK_BLEND_OP_INVERT_OVG_EXT = 1000148042,
VK_BLEND_OP_RED_EXT = 1000148043,
VK_BLEND_OP_GREEN_EXT = 1000148044,
VK_BLEND_OP_BLUE_EXT = 1000148045,
} VkBlendOp;
The semantics of each basic blend operations is described in the table below:
| VkBlendOp | RGB Components | Alpha Component |
|---|---|---|
|
R = Rs0 × Sr + Rd × Dr |
A = As0 × Sa + Ad × Da |
|
R = Rs0 × Sr - Rd × Dr |
A = As0 × Sa - Ad × Da |
|
R = Rd × Dr - Rs0 × Sr |
A = Ad × Da - As0 × Sa |
|
R = min(Rs0,Rd) |
A = min(As0,Ad) |
|
R = max(Rs0,Rd) |
A = max(As0,Ad) |
In this table, the following conventions are used:
-
Rs0, Gs0, Bs0 and As0 represent the first source color R, G, B, and A components, respectively.
-
Rd, Gd, Bd and Ad represent the R, G, B, and A components of the destination color. That is, the color currently in the corresponding color attachment for this fragment/sample.
-
Sr, Sg, Sb and Sa represent the source blend factor R, G, B, and A components, respectively.
-
Dr, Dg, Db and Da represent the destination blend factor R, G, B, and A components, respectively.
The blending operation produces a new set of values R, G, B and A, which are written to the framebuffer attachment. If blending is not enabled for this attachment, then R, G, B and A are assigned Rs0, Gs0, Bs0 and As0, respectively.
If the color attachment is fixed-point, the components of the source and destination values and blend factors are each clamped to [0,1] or [-1,1] respectively for an unsigned normalized or signed normalized color attachment prior to evaluating the blend operations. If the color attachment is floating-point, no clamping occurs.
If the numeric format of a framebuffer attachment uses sRGB encoding, the R, G, and B destination color values (after conversion from fixed-point to floating-point) are considered to be encoded for the sRGB color space and hence are linearized prior to their use in blending. Each R, G, and B component is converted from nonlinear to linear as described in the “sRGB EOTF” section of the Khronos Data Format Specification. If the format is not sRGB, no linearization is performed.
If the numeric format of a framebuffer attachment uses sRGB encoding, then the final R, G and B values are converted into the nonlinear sRGB representation before being written to the framebuffer attachment as described in the “sRGB EOTF -1” section of the Khronos Data Format Specification.
If the framebuffer color attachment numeric format is not sRGB encoded then the resulting cs values for R, G and B are unmodified. The value of A is never sRGB encoded. That is, the alpha component is always stored in memory as linear.
If the framebuffer color attachment is VK_ATTACHMENT_UNUSED, no writes
are performed through that attachment.
Framebuffer color attachments greater than or equal to
VkSubpassDescription::colorAttachmentCount perform no writes.
26.1.4. Advanced Blend Operations
The advanced blend operations are those listed in tables f/X/Y/Z Advanced Blend Operations, Hue-Saturation-Luminosity Advanced Blend Operations, and Additional RGB Blend Operations.
If the pNext chain of VkPipelineColorBlendStateCreateInfo
includes a VkPipelineColorBlendAdvancedStateCreateInfoEXT structure,
then that structure includes parameters that affect advanced blend
operations.
The VkPipelineColorBlendAdvancedStateCreateInfoEXT structure is
defined as:
typedef struct VkPipelineColorBlendAdvancedStateCreateInfoEXT {
VkStructureType sType;
const void* pNext;
VkBool32 srcPremultiplied;
VkBool32 dstPremultiplied;
VkBlendOverlapEXT blendOverlap;
} VkPipelineColorBlendAdvancedStateCreateInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
srcPremultipliedspecifies whether the source color of the blend operation is treated as premultiplied. -
dstPremultipliedspecifies whether the destination color of the blend operation is treated as premultiplied. -
blendOverlapis a VkBlendOverlapEXT value specifying how the source and destination sample’s coverage is correlated.
If this structure is not present, srcPremultiplied and
dstPremultiplied are both considered to be VK_TRUE, and
blendOverlap is considered to be
VK_BLEND_OVERLAP_UNCORRELATED_EXT.
When using one of the operations in table f/X/Y/Z Advanced Blend Operations or Hue-Saturation-Luminosity Advanced Blend Operations, blending is performed according to the following equations:
where the function f and terms X, Y, and Z are specified in the table.
The R, G, and B components of the source color used for blending are derived
according to srcPremultiplied.
If srcPremultiplied is set to VK_TRUE, the fragment color
components are considered to have been premultiplied by the A component
prior to blending.
The base source color (Rs',Gs',Bs') is obtained by dividing
through by the A component:
If srcPremultiplied is VK_FALSE, the fragment color components
are used as the base color:
The R, G, and B components of the destination color used for blending are
derived according to dstPremultiplied.
If dstPremultiplied is set to VK_TRUE, the destination
components are considered to have been premultiplied by the A component
prior to blending.
The base destination color (Rd',Gd',Bd') is obtained by dividing
through by the A component:
If dstPremultiplied is VK_FALSE, the destination color
components are used as the base color:
When blending using advanced blend operations, we expect that the R, G, and B components of premultiplied source and destination color inputs be stored as the product of non-premultiplied R, G, and B component values and the A component of the color. If any R, G, or B component of a premultiplied input color is non-zero and the A component is zero, the color is considered ill-formed, and the corresponding component of the blend result is undefined.
The weighting functions p0, p1, and p2 are defined in table Advanced Blend Overlap Modes. In these functions, the A components of the source and destination colors are taken to indicate the portion of the pixel covered by the fragment (source) and the fragments previously accumulated in the pixel (destination). The functions p0, p1, and p2 approximate the relative portion of the pixel covered by the intersection of the source and destination, covered only by the source, and covered only by the destination, respectively.
Possible values of
VkPipelineColorBlendAdvancedStateCreateInfoEXT::blendOverlap,
specifying the blend overlap functions, are:
typedef enum VkBlendOverlapEXT {
VK_BLEND_OVERLAP_UNCORRELATED_EXT = 0,
VK_BLEND_OVERLAP_DISJOINT_EXT = 1,
VK_BLEND_OVERLAP_CONJOINT_EXT = 2,
} VkBlendOverlapEXT;
-
VK_BLEND_OVERLAP_UNCORRELATED_EXTspecifies that there is no correlation between the source and destination coverage. -
VK_BLEND_OVERLAP_CONJOINT_EXTspecifies that the source and destination coverage are considered to have maximal overlap. -
VK_BLEND_OVERLAP_DISJOINT_EXTspecifies that the source and destination coverage are considered to have minimal overlap.
| Overlap Mode | Weighting Equations |
|---|---|
|
\[ \begin{aligned}
p_0(A_s,A_d) & = A_sA_d \\
p_1(A_s,A_d) & = A_s(1-A_d) \\
p_2(A_s,A_d) & = A_d(1-A_s) \\
\end{aligned}\]
|
|
\[ \begin{aligned}
p_0(A_s,A_d) & = min(A_s,A_d) \\
p_1(A_s,A_d) & = max(A_s-A_d,0) \\
p_2(A_s,A_d) & = max(A_d-A_s,0) \\
\end{aligned}\]
|
|
\[ \begin{aligned}
p_0(A_s,A_d) & = max(A_s+A_d-1,0) \\
p_1(A_s,A_d) & = min(A_s,1-A_d) \\
p_2(A_s,A_d) & = min(A_d,1-A_s) \\
\end{aligned}\]
|
| Mode | Blend Coefficients |
|---|---|
|
\[ \begin{aligned}
(X,Y,Z) & = (0,0,0) \\
f(C_s,C_d) & = 0
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,0) \\
f(C_s,C_d) & = C_s
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,0,1) \\
f(C_s,C_d) & = C_d
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & = C_s
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & = C_d
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,0,0) \\
f(C_s,C_d) & = C_s
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,0,0) \\
f(C_s,C_d) & = C_d
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (0,1,0) \\
f(C_s,C_d) & = 0
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (0,0,1) \\
f(C_s,C_d) & = 0
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,0,1) \\
f(C_s,C_d) & = C_s
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,0) \\
f(C_s,C_d) & = C_d
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (0,1,1) \\
f(C_s,C_d) & = 0
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & = C_sC_d
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & = C_s+C_d-C_sC_d
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & =
\begin{cases}
2 C_sC_d & C_d \leq 0.5 \\
1-2 (1-C_s)(1-C_d) & \text{otherwise}
\end{cases}
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & = min(C_s,C_d)
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & = max(C_s,C_d)
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & =
\begin{cases}
0 & C_d \leq 0 \\
min(1,\frac{C_d}{1-C_s}) & C_d \gt 0 \text{ and } C_s \lt 1 \\
1 & C_d \gt 0 \text{ and } C_s \geq 1
\end{cases}
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & =
\begin{cases}
1 & C_d \geq 1 \\
1 - min(1,\frac{1-C_d}{C_s}) & C_d \lt 1 \text{ and } C_s \gt 0 \\
0 & C_d \lt 1 \text{ and } C_s \leq 0
\end{cases}
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & =
\begin{cases}
2 C_sC_d & C_s \leq 0.5 \\
1-2 (1-C_s)(1-C_d) & \text{otherwise}
\end{cases}
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & =
\begin{cases}
C_d-(1-2 C_s)C_d(1-C_d) & C_s \leq 0.5 \\
C_d+(2 C_s-1)C_d((16 C_d-12)C_d+3) & C_s \gt 0.5 \text{ and } C_d \leq 0.25 \\
C_d+(2 C_s-1)(\sqrt{C_d}-C_d) & C_s \gt 0.5 \text{ and } C_d \gt 0.25
\end{cases}
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & = \lvert C_d-C_s \rvert
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & = C_s+C_d-2C_sC_d
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,0,1) \\
f(C_s,C_d) & = 1-C_d
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,0,1) \\
f(C_s,C_d) & = C_s(1-C_d)
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & =
\begin{cases}
C_s+C_d & C_s+C_d \leq 1 \\
1 & \text{otherwise}
\end{cases}
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & =
\begin{cases}
C_s+C_d-1 & C_s+C_d \gt 1 \\
0 & \text{otherwise}
\end{cases}
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & =
\begin{cases}
1-min(1,\frac{1-C_d}{2C_s}) & 0 \lt C_s \lt 0.5 \\
0 & C_s \leq 0 \\
min(1,\frac{C_d}{2(1-C_s)}) & 0.5 \leq C_s \lt 1 \\
1 & C_s \geq 1
\end{cases}
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & =
\begin{cases}
1 & 2C_s+C_d \gt 2 \\
2C_s+C_d-1 & 1 \lt 2C_s+C_d \leq 2 \\
0 & 2C_s+C_d \leq 1
\end{cases}
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & =
\begin{cases}
0 & 2C_s-1 \gt C_d \text{ and } C_s \lt 0.5 \\
2C_s-1 & 2C_s-1 \gt C_d \text{ and } C_s \geq 0.5 \\
2C_s & 2C_s-1 \leq C_d \text{ and } C_s \lt 0.5C_d \\
C_d & 2C_s-1 \leq C_d \text{ and } C_s \geq 0.5C_d
\end{cases}
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & =
\begin{cases}
0 & C_s+C_d \lt 1 \\
1 & \text{otherwise}
\end{cases}
\end{aligned}\]
|
When using one of the HSL blend operations in table Hue-Saturation-Luminosity Advanced Blend Operations as the blend operation, the RGB color components produced by the function f are effectively obtained by converting both the non-premultiplied source and destination colors to the HSL (hue, saturation, luminosity) color space, generating a new HSL color by selecting H, S, and L components from the source or destination according to the blend operation, and then converting the result back to RGB. In the equations below, a blended RGB color is produced according to the following pseudocode:
float minv3(vec3 c) {
return min(min(c.r, c.g), c.b);
}
float maxv3(vec3 c) {
return max(max(c.r, c.g), c.b);
}
float lumv3(vec3 c) {
return dot(c, vec3(0.30, 0.59, 0.11));
}
float satv3(vec3 c) {
return maxv3(c) - minv3(c);
}
// If any color components are outside [0,1], adjust the color to
// get the components in range.
vec3 ClipColor(vec3 color) {
float lum = lumv3(color);
float mincol = minv3(color);
float maxcol = maxv3(color);
if (mincol < 0.0) {
color = lum + ((color-lum)*lum) / (lum-mincol);
}
if (maxcol > 1.0) {
color = lum + ((color-lum)*lum) / (maxcol-lum);
}
return color;
}
// Take the base RGB color <cbase> and override its luminosity
// with that of the RGB color <clum>.
vec3 SetLum(vec3 cbase, vec3 clum) {
float lbase = lumv3(cbase);
float llum = lumv3(clum);
float ldiff = llum - lbase;
vec3 color = cbase + vec3(ldiff);
return ClipColor(color);
}
// Take the base RGB color <cbase> and override its saturation with
// that of the RGB color <csat>. The override the luminosity of the
// result with that of the RGB color <clum>.
vec3 SetLumSat(vec3 cbase, vec3 csat, vec3 clum)
{
float minbase = minv3(cbase);
float sbase = satv3(cbase);
float ssat = satv3(csat);
vec3 color;
if (sbase > 0) {
// Equivalent (modulo rounding errors) to setting the
// smallest (R,G,B) component to 0, the largest to <ssat>,
// and interpolating the "middle" component based on its
// original value relative to the smallest/largest.
color = (cbase - minbase) * ssat / sbase;
} else {
color = vec3(0.0);
}
return SetLum(color, clum);
}
| Mode | Result |
|---|---|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & = SetLumSat(C_s,C_d,C_d)
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & = SetLumSat(C_d,C_s,C_d)
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & = SetLum(C_s,C_d)
\end{aligned}\]
|
|
\[ \begin{aligned}
(X,Y,Z) & = (1,1,1) \\
f(C_s,C_d) & = SetLum(C_d,C_s)
\end{aligned}\]
|
When using one of the operations in table
Additional RGB Blend
Operations as the blend operation, the source and destination colors used
by these blending operations are interpreted according to
srcPremultiplied and dstPremultiplied.
The blending operations below are evaluated where the RGB source and
destination color components are both considered to have been premultiplied
by the corresponding A component.
| Mode | Result |
|---|---|
|
\[ \begin{aligned}
(R,G,B,A) = ( & R_s'+R_d', \\
& G_s'+G_d', \\
& B_s'+B_d', \\
& A_s+A_d)
\end{aligned}\]
|
|
\[ \begin{aligned}
(R,G,B,A) = ( & min(1,R_s'+R_d'), \\
& min(1,G_s'+G_d'), \\
& min(1,B_s'+B_d'), \\
& min(1,A_s+A_d))
\end{aligned}\]
|
|
\[ \begin{aligned}
(R,G,B,A) = ( & min(min(1,A_s+A_d),R_s'+R_d'), \\
& min(min(1,A_s+A_d),G_s'+G_d'), \\
& min(min(1,A_s+A_d),B_s'+B_d'), \\
& min(1,A_s+A_d))
\end{aligned}\]
|
|
\[ \begin{aligned}
(R,G,B,A) = ( & max(0,min(1,A_s+A_d)-((A_s-R_s')+(A_d-R_d'))), \\
& max(0,min(1,A_s+A_d)-((A_s-G_s')+(A_d-G_d'))), \\
& max(0,min(1,A_s+A_d)-((A_s-B_s')+(A_d-B_d'))), \\
& min(1,A_s+A_d))
\end{aligned}\]
|
|
\[ \begin{aligned}
(R,G,B,A) = ( & R_d'-R_s', \\
& G_d'-G_s', \\
& B_d'-B_s', \\
& A_d-A_s)
\end{aligned}\]
|
|
\[ \begin{aligned}
(R,G,B,A) = ( & max(0,R_d'-R_s'), \\
& max(0,G_d'-G_s'), \\
& max(0,B_d'-B_s'), \\
& max(0,A_d-A_s))
\end{aligned}\]
|
|
\[ \begin{aligned}
(R,G,B,A) = ( & \frac{A_d}{2} + 2(R_d'-\frac{A_d}{2})(R_s'-\frac{A_s}{2}), \\
& \frac{A_d}{2} + 2(G_d'-\frac{A_d}{2})(G_s'-\frac{A_s}{2}), \\
& \frac{A_d}{2} + 2(B_d'-\frac{A_d}{2})(B_s'-\frac{A_s}{2}), \\
& A_d)
\end{aligned}\]
|
|
\[ \begin{aligned}
(R,G,B,A) = ( & A_s(1-R_d') + (1-A_s)R_d', \\
& A_s(1-G_d') + (1-A_s)G_d', \\
& A_s(1-B_d') + (1-A_s)B_d', \\
& A_s+A_d-A_sA_d)
\end{aligned}\]
|
|
\[ \begin{aligned}
(R,G,B,A) & = (R_s', G_d', B_d', A_d)
\end{aligned}\]
|
|
\[ \begin{aligned}
(R,G,B,A) & = (R_d', G_s', B_d', A_d)
\end{aligned}\]
|
|
\[ \begin{aligned}
(R,G,B,A) & = (R_d', G_d', B_s', A_d)
\end{aligned}\]
|
26.2. Logical Operations
The application can enable a logical operation between the fragment’s color values and the existing value in the framebuffer attachment. This logical operation is applied prior to updating the framebuffer attachment. Logical operations are applied only for signed and unsigned integer and normalized integer framebuffers. Logical operations are not applied to floating-point or sRGB format color attachments.
Logical operations are controlled by the logicOpEnable and
logicOp members of VkPipelineColorBlendStateCreateInfo.
If logicOpEnable is VK_TRUE, then a logical operation selected
by logicOp is applied between each color attachment and the fragment’s
corresponding output value, and blending of all attachments is treated as if
it were disabled.
Any attachments using color formats for which logical operations are not
supported simply pass through the color values unmodified.
The logical operation is applied independently for each of the red, green,
blue, and alpha components.
The logicOp is selected from the following operations:
typedef enum VkLogicOp {
VK_LOGIC_OP_CLEAR = 0,
VK_LOGIC_OP_AND = 1,
VK_LOGIC_OP_AND_REVERSE = 2,
VK_LOGIC_OP_COPY = 3,
VK_LOGIC_OP_AND_INVERTED = 4,
VK_LOGIC_OP_NO_OP = 5,
VK_LOGIC_OP_XOR = 6,
VK_LOGIC_OP_OR = 7,
VK_LOGIC_OP_NOR = 8,
VK_LOGIC_OP_EQUIVALENT = 9,
VK_LOGIC_OP_INVERT = 10,
VK_LOGIC_OP_OR_REVERSE = 11,
VK_LOGIC_OP_COPY_INVERTED = 12,
VK_LOGIC_OP_OR_INVERTED = 13,
VK_LOGIC_OP_NAND = 14,
VK_LOGIC_OP_SET = 15,
} VkLogicOp;
The logical operations supported by Vulkan are summarized in the following table in which
-
¬ is bitwise invert,
-
∧ is bitwise and,
-
∨ is bitwise or,
-
⊕ is bitwise exclusive or,
-
s is the fragment’s Rs0, Gs0, Bs0 or As0 component value for the fragment output corresponding to the color attachment being updated, and
-
d is the color attachment’s R, G, B or A component value:
| Mode | Operation |
|---|---|
|
0 |
|
s ∧ d |
|
s ∧ ¬ d |
|
s |
|
¬ s ∧ d |
|
d |
|
s ⊕ d |
|
s ∨ d |
|
¬ (s ∨ d) |
|
¬ (s ⊕ d) |
|
¬ d |
|
s ∨ ¬ d |
|
¬ s |
|
¬ s ∨ d |
|
¬ (s ∧ d) |
|
all 1s |
The result of the logical operation is then written to the color attachment as controlled by the component write mask, described in Blend Operations.
26.3. Color Write Mask
Bits which can be set in
VkPipelineColorBlendAttachmentState::colorWriteMask to determine
whether the final color values R, G, B and A are written to the
framebuffer attachment are:
typedef enum VkColorComponentFlagBits {
VK_COLOR_COMPONENT_R_BIT = 0x00000001,
VK_COLOR_COMPONENT_G_BIT = 0x00000002,
VK_COLOR_COMPONENT_B_BIT = 0x00000004,
VK_COLOR_COMPONENT_A_BIT = 0x00000008,
} VkColorComponentFlagBits;
-
VK_COLOR_COMPONENT_R_BITspecifies that the R value is written to the color attachment for the appropriate sample. Otherwise, the value in memory is unmodified. -
VK_COLOR_COMPONENT_G_BITspecifies that the G value is written to the color attachment for the appropriate sample. Otherwise, the value in memory is unmodified. -
VK_COLOR_COMPONENT_B_BITspecifies that the B value is written to the color attachment for the appropriate sample. Otherwise, the value in memory is unmodified. -
VK_COLOR_COMPONENT_A_BITspecifies that the A value is written to the color attachment for the appropriate sample. Otherwise, the value in memory is unmodified.
The color write mask operation is applied regardless of whether blending is enabled.
typedef VkFlags VkColorComponentFlags;
VkColorComponentFlags is a bitmask type for setting a mask of zero or
more VkColorComponentFlagBits.
27. Dispatching Commands
Dispatching commands (commands with Dispatch in the name) provoke
work in a compute pipeline.
Dispatching commands are recorded into a command buffer and when executed by
a queue, will produce work which executes according to the bound compute
pipeline.
A compute pipeline must be bound to a command buffer before any dispatch
commands are recorded in that command buffer.
To record a dispatch, call:
void vkCmdDispatch(
VkCommandBuffer commandBuffer,
uint32_t groupCountX,
uint32_t groupCountY,
uint32_t groupCountZ);
-
commandBufferis the command buffer into which the command will be recorded. -
groupCountXis the number of local workgroups to dispatch in the X dimension. -
groupCountYis the number of local workgroups to dispatch in the Y dimension. -
groupCountZis the number of local workgroups to dispatch in the Z dimension.
When the command is executed, a global workgroup consisting of groupCountX × groupCountY × groupCountZ local workgroups is assembled.
To record an indirect command dispatch, call:
void vkCmdDispatchIndirect(
VkCommandBuffer commandBuffer,
VkBuffer buffer,
VkDeviceSize offset);
-
commandBufferis the command buffer into which the command will be recorded. -
bufferis the buffer containing dispatch parameters. -
offsetis the byte offset intobufferwhere parameters begin.
vkCmdDispatchIndirect behaves similarly to vkCmdDispatch except
that the parameters are read by the device from a buffer during execution.
The parameters of the dispatch are encoded in a
VkDispatchIndirectCommand structure taken from buffer starting
at offset.
The VkDispatchIndirectCommand structure is defined as:
typedef struct VkDispatchIndirectCommand {
uint32_t x;
uint32_t y;
uint32_t z;
} VkDispatchIndirectCommand;
-
xis the number of local workgroups to dispatch in the X dimension. -
yis the number of local workgroups to dispatch in the Y dimension. -
zis the number of local workgroups to dispatch in the Z dimension.
The members of VkDispatchIndirectCommand have the same meaning as the
corresponding parameters of vkCmdDispatch.
To record a dispatch using non-zero base values for the components of
WorkgroupId, call:
void vkCmdDispatchBase(
VkCommandBuffer commandBuffer,
uint32_t baseGroupX,
uint32_t baseGroupY,
uint32_t baseGroupZ,
uint32_t groupCountX,
uint32_t groupCountY,
uint32_t groupCountZ);
or the equivalent command
void vkCmdDispatchBaseKHR(
VkCommandBuffer commandBuffer,
uint32_t baseGroupX,
uint32_t baseGroupY,
uint32_t baseGroupZ,
uint32_t groupCountX,
uint32_t groupCountY,
uint32_t groupCountZ);
-
commandBufferis the command buffer into which the command will be recorded. -
baseGroupXis the start value for the X component ofWorkgroupId. -
baseGroupYis the start value for the Y component ofWorkgroupId. -
baseGroupZis the start value for the Z component ofWorkgroupId. -
groupCountXis the number of local workgroups to dispatch in the X dimension. -
groupCountYis the number of local workgroups to dispatch in the Y dimension. -
groupCountZis the number of local workgroups to dispatch in the Z dimension.
When the command is executed, a global workgroup consisting of
groupCountX × groupCountY × groupCountZ local workgroups
is assembled, with WorkgroupId values ranging from [baseGroup,
baseGroup + groupCount) in each component.
vkCmdDispatch is equivalent to
vkCmdDispatchBase(0,0,0,groupCountX,groupCountY,groupCountZ).
28. Device-Generated Commands
This chapter discusses the generation of command buffer content on the device. These principle steps are to be taken to generate commands on the device:
-
Make resource bindings accessible for the device via registering in an
VkObjectTableNVX. -
Define via
VkIndirectCommandsLayoutNVXthe sequence of commands which should be generated. -
Fill one or more
VkBufferwith the appropriate content that gets interpreted byVkIndirectCommandsLayoutNVX. -
Reserve command space via vkCmdReserveSpaceForCommandsNVX in a secondary
VkCommandBufferwhere the generated commands should be recorded. -
Generate the actual commands via vkCmdProcessCommandsNVX passing all required data.
Execution of such generated commands can either be triggered directly with
the generation process, or by executing the secondary VkCommandBuffer
that was chosen as optional target.
The latter allows re-using generated commands as well.
Similar to VkDescriptorSet, special care should be taken for the
lifetime of resources referenced in VkObjectTableNVX, which may be
accessed at either generation or execution time.
vkCmdProcessCommandsNVX executes in a separate logical pipeline from either graphics or compute. When generating commands into a secondary command buffer, the command generation must be explicitly synchronized against the secondary command buffer’s execution. When not using a secondary command buffer, the command generation is automatically synchronized against the command execution.
28.1. Features and Limitations
To query the support of related features and limitations, call:
void vkGetPhysicalDeviceGeneratedCommandsPropertiesNVX(
VkPhysicalDevice physicalDevice,
VkDeviceGeneratedCommandsFeaturesNVX* pFeatures,
VkDeviceGeneratedCommandsLimitsNVX* pLimits);
-
physicalDeviceis the handle to the physical device whose properties will be queried. -
pFeaturespoints to an instance of the VkDeviceGeneratedCommandsFeaturesNVX structure, that will be filled with returned information. -
pLimitspoints to an instance of the VkDeviceGeneratedCommandsLimitsNVX structure, that will be filled with returned information.
The VkDeviceGeneratedCommandsFeaturesNVX structure is defined as:
typedef struct VkDeviceGeneratedCommandsFeaturesNVX {
VkStructureType sType;
const void* pNext;
VkBool32 computeBindingPointSupport;
} VkDeviceGeneratedCommandsFeaturesNVX;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
computeBindingPointSupportspecifies whether theVkObjectTableNVXsupports entries withVK_OBJECT_ENTRY_USAGE_GRAPHICS_BIT_NVXbit set andVkIndirectCommandsLayoutNVXsupportsVK_PIPELINE_BIND_POINT_COMPUTE.
The VkDeviceGeneratedCommandsLimitsNVX structure is defined as:
typedef struct VkDeviceGeneratedCommandsLimitsNVX {
VkStructureType sType;
const void* pNext;
uint32_t maxIndirectCommandsLayoutTokenCount;
uint32_t maxObjectEntryCounts;
uint32_t minSequenceCountBufferOffsetAlignment;
uint32_t minSequenceIndexBufferOffsetAlignment;
uint32_t minCommandsTokenBufferOffsetAlignment;
} VkDeviceGeneratedCommandsLimitsNVX;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
maxIndirectCommandsLayoutTokenCountthe maximum number of tokens inVkIndirectCommandsLayoutNVX. -
maxObjectEntryCountsthe maximum number of entries per resource type inVkObjectTableNVX. -
minSequenceCountBufferOffsetAlignmentthe minimum alignment for memory addresses optionally used invkCmdProcessCommandsNVX. -
minSequenceIndexBufferOffsetAlignmentthe minimum alignment for memory addresses optionally used invkCmdProcessCommandsNVX. -
minCommandsTokenBufferOffsetAlignmentthe minimum alignment for memory addresses optionally used invkCmdProcessCommandsNVX.
28.2. Binding Object Table
The device-side bindings are registered inside a table:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkObjectTableNVX)
This is required as the CPU-side object pointers, for example when binding a
VkPipeline or VkDescriptorSet, cannot be used by the device.
The combination of VkObjectTableNVX and uint32_t table indices
stored inside a VkBuffer serve that purpose during device command
generation.
At creation time the table is defined with a fixed amount of registration
slots for the individual resource types.
A detailed resource binding can then later be registered via
vkRegisterObjectsNVX at any uint32_t index below the allocated
maximum.
28.2.1. Table Creation
To create object tables, call:
VkResult vkCreateObjectTableNVX(
VkDevice device,
const VkObjectTableCreateInfoNVX* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkObjectTableNVX* pObjectTable);
-
deviceis the logical device that creates the object table. -
pCreateInfois a pointer to an instance of theVkObjectTableCreateInfoNVXstructure containing parameters affecting creation of the table. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pObjectTablepoints to aVkObjectTableNVXhandle in which the resulting object table is returned.
The VkObjectTableCreateInfoNVX structure is defined as:
typedef struct VkObjectTableCreateInfoNVX {
VkStructureType sType;
const void* pNext;
uint32_t objectCount;
const VkObjectEntryTypeNVX* pObjectEntryTypes;
const uint32_t* pObjectEntryCounts;
const VkObjectEntryUsageFlagsNVX* pObjectEntryUsageFlags;
uint32_t maxUniformBuffersPerDescriptor;
uint32_t maxStorageBuffersPerDescriptor;
uint32_t maxStorageImagesPerDescriptor;
uint32_t maxSampledImagesPerDescriptor;
uint32_t maxPipelineLayouts;
} VkObjectTableCreateInfoNVX;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
objectCountis the number of entry configurations that the object table supports. -
pObjectEntryTypesis an array of VkObjectEntryTypeNVX values providing the entry type of a given configuration. -
pObjectEntryCountsis an array of counts of how many objects can be registered in the table. -
pObjectEntryUsageFlagsis an array of bitmasks of VkObjectEntryUsageFlagBitsNVX specifying the binding usage of the entry. -
maxUniformBuffersPerDescriptoris the maximum number ofVK_DESCRIPTOR_TYPE_UNIFORM_BUFFERorVK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMICused by any single registeredVkDescriptorSetin this table. -
maxStorageBuffersPerDescriptoris the maximum number ofVK_DESCRIPTOR_TYPE_STORAGE_BUFFERorVK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMICused by any single registeredVkDescriptorSetin this table. -
maxStorageImagesPerDescriptoris the maximum number ofVK_DESCRIPTOR_TYPE_STORAGE_IMAGEorVK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFERused by any single registeredVkDescriptorSetin this table. -
maxSampledImagesPerDescriptoris the maximum number ofVK_DESCRIPTOR_TYPE_SAMPLER,VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER,VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFERorVK_DESCRIPTOR_TYPE_INPUT_ATTACHMENTused by any single registeredVkDescriptorSetin this table. -
maxPipelineLayoutsis the maximum number of uniqueVkPipelineLayoutused by any registeredVkDescriptorSetorVkPipelinein this table.
Possible values of elements of the
VkObjectTableCreateInfoNVX::pObjectEntryTypes array, specifying
the entry type of a configuration, are:
typedef enum VkObjectEntryTypeNVX {
VK_OBJECT_ENTRY_TYPE_DESCRIPTOR_SET_NVX = 0,
VK_OBJECT_ENTRY_TYPE_PIPELINE_NVX = 1,
VK_OBJECT_ENTRY_TYPE_INDEX_BUFFER_NVX = 2,
VK_OBJECT_ENTRY_TYPE_VERTEX_BUFFER_NVX = 3,
VK_OBJECT_ENTRY_TYPE_PUSH_CONSTANT_NVX = 4,
} VkObjectEntryTypeNVX;
-
VK_OBJECT_ENTRY_TYPE_DESCRIPTOR_SET_NVXspecifies aVkDescriptorSetresource entry that is registered viaVkObjectTableDescriptorSetEntryNVX. -
VK_OBJECT_ENTRY_TYPE_PIPELINE_NVXspecifies aVkPipelineresource entry that is registered viaVkObjectTablePipelineEntryNVX. -
VK_OBJECT_ENTRY_TYPE_INDEX_BUFFER_NVXspecifies aVkBufferresource entry that is registered viaVkObjectTableIndexBufferEntryNVX. -
VK_OBJECT_ENTRY_TYPE_VERTEX_BUFFER_NVXspecifies aVkBufferresource entry that is registered viaVkObjectTableVertexBufferEntryNVX. -
VK_OBJECT_ENTRY_TYPE_PUSH_CONSTANT_NVXspecifies the resource entry is registered viaVkObjectTablePushConstantEntryNVX.
Bits which can be set in elements of the
VkObjectTableCreateInfoNVX::pObjectEntryUsageFlags array,
specifying binding usage of an entry, are:
typedef enum VkObjectEntryUsageFlagBitsNVX {
VK_OBJECT_ENTRY_USAGE_GRAPHICS_BIT_NVX = 0x00000001,
VK_OBJECT_ENTRY_USAGE_COMPUTE_BIT_NVX = 0x00000002,
} VkObjectEntryUsageFlagBitsNVX;
-
VK_OBJECT_ENTRY_USAGE_GRAPHICS_BIT_NVXspecifies that the resource is bound toVK_PIPELINE_BIND_POINT_GRAPHICS -
VK_OBJECT_ENTRY_USAGE_COMPUTE_BIT_NVXspecifies that the resource is bound toVK_PIPELINE_BIND_POINT_COMPUTE
typedef VkFlags VkObjectEntryUsageFlagsNVX;
VkObjectEntryUsageFlagsNVX is a bitmask type for setting a mask of
zero or more VkObjectEntryUsageFlagBitsNVX.
To destroy an object table, call:
void vkDestroyObjectTableNVX(
VkDevice device,
VkObjectTableNVX objectTable,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the table. -
objectTableis the table to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
28.2.2. Registering Objects
Resource bindings of Vulkan objects are registered at an arbitrary
uint32_t index within an object table.
As long as the object table references such objects, they must not be
deleted.
VkResult vkRegisterObjectsNVX(
VkDevice device,
VkObjectTableNVX objectTable,
uint32_t objectCount,
const VkObjectTableEntryNVX* const* ppObjectTableEntries,
const uint32_t* pObjectIndices);
-
deviceis the logical device that creates the object table. -
objectTableis the table for which the resources are registered. -
objectCountis the number of resources to register. -
ppObjectTableEntriesprovides an array for detailed binding informations, each array element is a pointer to a struct of typeVkObjectTablePipelineEntryNVX,VkObjectTableDescriptorSetEntryNVX,VkObjectTableVertexBufferEntryNVX,VkObjectTableIndexBufferEntryNVXorVkObjectTablePushConstantEntryNVX(see below for details). -
pObjectIndicesare the indices at which each resource is registered.
Common to all resource entries are:
typedef struct VkObjectTableEntryNVX {
VkObjectEntryTypeNVX type;
VkObjectEntryUsageFlagsNVX flags;
} VkObjectTableEntryNVX;
-
typedefines the entry type -
flagsdefines whichVkPipelineBindPointthe resource can be used with. Some entry types allow only a single flag to be set.
typedef struct VkObjectTablePipelineEntryNVX {
VkObjectEntryTypeNVX type;
VkObjectEntryUsageFlagsNVX flags;
VkPipeline pipeline;
} VkObjectTablePipelineEntryNVX;
-
pipelinespecifies theVkPipelinethat this resource entry references.
typedef struct VkObjectTableDescriptorSetEntryNVX {
VkObjectEntryTypeNVX type;
VkObjectEntryUsageFlagsNVX flags;
VkPipelineLayout pipelineLayout;
VkDescriptorSet descriptorSet;
} VkObjectTableDescriptorSetEntryNVX;
-
pipelineLayoutspecifies theVkPipelineLayoutthat thedescriptorSetis used with. -
descriptorSetspecifies theVkDescriptorSetthat can be bound with this entry.
typedef struct VkObjectTableVertexBufferEntryNVX {
VkObjectEntryTypeNVX type;
VkObjectEntryUsageFlagsNVX flags;
VkBuffer buffer;
} VkObjectTableVertexBufferEntryNVX;
-
bufferspecifies theVkBufferthat can be bound as vertex bufer
typedef struct VkObjectTableIndexBufferEntryNVX {
VkObjectEntryTypeNVX type;
VkObjectEntryUsageFlagsNVX flags;
VkBuffer buffer;
VkIndexType indexType;
} VkObjectTableIndexBufferEntryNVX;
-
bufferspecifies theVkBufferthat can be bound as index buffer -
indexTypespecifies theVkIndexTypeused with this index buffer
typedef struct VkObjectTablePushConstantEntryNVX {
VkObjectEntryTypeNVX type;
VkObjectEntryUsageFlagsNVX flags;
VkPipelineLayout pipelineLayout;
VkShaderStageFlags stageFlags;
} VkObjectTablePushConstantEntryNVX;
-
pipelineLayoutspecifies theVkPipelineLayoutthat the pushconstants are used with -
stageFlagsspecifies theVkShaderStageFlagsthat the pushconstants are used with
Use the following command to unregister resources from an object table:
VkResult vkUnregisterObjectsNVX(
VkDevice device,
VkObjectTableNVX objectTable,
uint32_t objectCount,
const VkObjectEntryTypeNVX* pObjectEntryTypes,
const uint32_t* pObjectIndices);
-
deviceis the logical device that creates the object table. -
objectTableis the table from which the resources are unregistered. -
objectCountis the number of resources being removed from the object table. -
pObjectEntryTypeprovides an array ofVkObjectEntryTypeNVXfor the resources being removed. -
pObjectIndicesprovides the array of object indices to be removed.
28.3. Indirect Commands Layout
The device-side command generation happens through an iterative processing of an atomic sequence comprised of command tokens, which are represented by:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkIndirectCommandsLayoutNVX)
28.3.1. Tokenized Command Processing
The processing is in principle illustrated below:
void cmdProcessSequence(cmd, objectTable, indirectCommandsLayout, pIndirectCommandsTokens, s)
{
for (c = 0; c < indirectCommandsLayout.tokenCount; c++)
{
indirectCommandsLayout.pTokens[c].command (cmd, objectTable, pIndirectCommandsTokens[c], s);
}
}
void cmdProcessAllSequences(cmd, objectTable, indirectCommandsLayout, pIndirectCommandsTokens, sequencesCount)
{
for (s = 0; s < sequencesCount; s++)
{
cmdProcessSequence(cmd, objectTable, indirectCommandsLayout, pIndirectCommandsTokens, s);
}
}
The processing of each sequence is considered stateless, therefore all state
changes must occur prior work provoking commands within the sequence.
A single sequence is either strictly targeting
VK_PIPELINE_BIND_POINT_GRAPHICS or
VK_PIPELINE_BIND_POINT_COMPUTE.
The primary input data for each token is provided through VkBuffer
content at command generation time using vkCmdProcessCommandsNVX,
however some functional arguments, for example binding sets, are specified
at layout creation time.
The input size is different for each token.
Possible values of those elements of the
VkIndirectCommandsLayoutCreateInfoNVX::pTokens array which
specify command tokens (other elements of the array specify command
parameters) are:
typedef enum VkIndirectCommandsTokenTypeNVX {
VK_INDIRECT_COMMANDS_TOKEN_TYPE_PIPELINE_NVX = 0,
VK_INDIRECT_COMMANDS_TOKEN_TYPE_DESCRIPTOR_SET_NVX = 1,
VK_INDIRECT_COMMANDS_TOKEN_TYPE_INDEX_BUFFER_NVX = 2,
VK_INDIRECT_COMMANDS_TOKEN_TYPE_VERTEX_BUFFER_NVX = 3,
VK_INDIRECT_COMMANDS_TOKEN_TYPE_PUSH_CONSTANT_NVX = 4,
VK_INDIRECT_COMMANDS_TOKEN_TYPE_DRAW_INDEXED_NVX = 5,
VK_INDIRECT_COMMANDS_TOKEN_TYPE_DRAW_NVX = 6,
VK_INDIRECT_COMMANDS_TOKEN_TYPE_DISPATCH_NVX = 7,
} VkIndirectCommandsTokenTypeNVX;
| Token type | Equivalent command |
|---|---|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
The VkIndirectCommandsLayoutTokenNVX structure specifies details to
the function arguments that need to be known at layout creation time:
typedef struct VkIndirectCommandsLayoutTokenNVX {
VkIndirectCommandsTokenTypeNVX tokenType;
uint32_t bindingUnit;
uint32_t dynamicCount;
uint32_t divisor;
} VkIndirectCommandsLayoutTokenNVX;
-
typespecifies the token command type. -
bindingUnithas a different meaning depending on the type, please refer pseudo code further down for details. -
dynamicCounthas a different meaning depending on the type, please refer pseudo code further down for details. -
divisordefines the rate at which the input data buffers are accessed.
The VkIndirectCommandsTokenNVX structure specifies the input data for
a token at processing time.
typedef struct VkIndirectCommandsTokenNVX {
VkIndirectCommandsTokenTypeNVX tokenType;
VkBuffer buffer;
VkDeviceSize offset;
} VkIndirectCommandsTokenNVX;
-
tokenTypespecifies the token command type. -
bufferspecifies theVkBufferstoring the functional arguments for each squence. These argumetns can be written by the device. -
offsetspecified an offset intobufferwhere the arguments start.
The following code provides detailed information on how an individual sequence is processed:
void cmdProcessSequence(cmd, objectTable, indirectCommandsLayout, pIndirectCommandsTokens, s)
{
for (uint32_t c = 0; c < indirectCommandsLayout.tokenCount; c++){
input = pIndirectCommandsTokens[c];
i = s / indirectCommandsLayout.pTokens[c].divisor;
switch(input.type){
VK_INDIRECT_COMMANDS_TOKEN_TYPE_PIPELINE_NVX:
size_t stride = sizeof(uint32_t);
uint32_t* data = input.buffer.pointer( input.offset + stride * i );
uint32_t object = data[0];
vkCmdBindPipeline(cmd, indirectCommandsLayout.pipelineBindPoint,
objectTable.pipelines[ object ].pipeline);
break;
VK_INDIRECT_COMMANDS_TOKEN_TYPE_DESCRIPTOR_SET_NVX:
size_t stride = sizeof(uint32_t) + sizeof(uint32_t) * indirectCommandsLayout.pTokens[c].dynamicCount;
uint32_t* data = input.buffer.pointer( input.offset + stride * i);
uint32_t object = data[0];
vkCmdBindDescriptorSets(cmd, indirectCommandsLayout.pipelineBindPoint,
objectTable.descriptorsets[ object ].layout,
indirectCommandsLayout.pTokens[ c ].bindingUnit,
1, &objectTable.descriptorsets[ object ].descriptorSet,
indirectCommandsLayout.pTokens[ c ].dynamicCount, data + 1);
break;
VK_INDIRECT_COMMANDS_TOKEN_TYPE_PUSH_CONSTANT_NVX:
size_t stride = sizeof(uint32_t) + indirectCommandsLayout.pTokens[c].dynamicCount;
uint32_t* data = input.buffer.pointer( input.offset + stride * i );
uint32_t object = data[0];
vkCmdPushConstants(cmd,
objectTable.pushconstants[ object ].layout,
objectTable.pushconstants[ object ].stageFlags,
indirectCommandsLayout.pTokens[ c ].bindingUnit, indirectCommandsLayout.pTokens[c].dynamicCount, data + 1);
break;
VK_INDIRECT_COMMANDS_TOKEN_TYPE_INDEX_BUFFER_NVX:
size_t s tride = sizeof(uint32_t) + sizeof(uint32_t) * indirectCommandsLayout.pTokens[c].dynamicCount;
uint32_t* data = input.buffer.pointer( input.offset + stride * i );
uint32_t object = data[0];
vkCmdBindIndexBuffer(cmd,
objectTable.vertexbuffers[ object ].buffer,
indirectCommandsLayout.pTokens[ c ].dynamicCount ? data[1] : 0,
objectTable.vertexbuffers[ object ].indexType);
break;
VK_INDIRECT_COMMANDS_TOKEN_TYPE_VERTEX_BUFFER_NVX:
size_t stride = sizeof(uint32_t) + sizeof(uint32_t) * indirectCommandsLayout.pTokens[c].dynamicCount;
uint32_t* data = input.buffer.pointer( input.offset + stride * i );
uint32_t object = data[0];
vkCmdBindVertexBuffers(cmd,
indirectCommandsLayout.pTokens[ c ].bindingUnit, 1,
&objectTable.vertexbuffers[ object ].buffer,
indirectCommandsLayout.pTokens[ c ].dynamicCount ? data + 1 : {0}); // device size handled as uint32_t
break;
VK_INDIRECT_COMMANDS_TOKEN_TYPE_DRAW_INDEXED_NVX:
vkCmdDrawIndexedIndirect(cmd,
input.buffer,
sizeof(VkDrawIndexedIndirectCommand) * i + input.offset, 1, 0);
break;
VK_INDIRECT_COMMANDS_TOKEN_TYPE_DRAW_NVX:
vkCmdDrawIndirect(cmd,
input.buffer,
sizeof(VkDrawIndirectCommand) * i + input.offset, 1, 0);
break;
VK_INDIRECT_COMMANDS_TOKEN_TYPE_DISPATCH_NVX:
vkCmdDispatchIndirect(cmd,
input.buffer,
sizeof(VkDispatchIndirectCommand) * i + input.offset);
break;
}
}
}
28.3.2. Creation and Deletion
Indirect command layouts are created by:
VkResult vkCreateIndirectCommandsLayoutNVX(
VkDevice device,
const VkIndirectCommandsLayoutCreateInfoNVX* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkIndirectCommandsLayoutNVX* pIndirectCommandsLayout);
-
deviceis the logical device that creates the indirect command layout. -
pCreateInfois a pointer to an instance of theVkIndirectCommandsLayoutCreateInfoNVXstructure containing parameters affecting creation of the indirect command layout. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pIndirectCommandsLayoutpoints to aVkIndirectCommandsLayoutNVXhandle in which the resulting indirect command layout is returned.
The VkIndirectCommandsLayoutCreateInfoNVX structure is defined as:
typedef struct VkIndirectCommandsLayoutCreateInfoNVX {
VkStructureType sType;
const void* pNext;
VkPipelineBindPoint pipelineBindPoint;
VkIndirectCommandsLayoutUsageFlagsNVX flags;
uint32_t tokenCount;
const VkIndirectCommandsLayoutTokenNVX* pTokens;
} VkIndirectCommandsLayoutCreateInfoNVX;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
pipelineBindPointis theVkPipelineBindPointthat this layout targets. -
flagsis a bitmask of VkIndirectCommandsLayoutUsageFlagBitsNVX specifying usage hints of this layout. -
tokenCountis the length of the individual command sequnce. -
pTokensis an array describing each command token in detail. See VkIndirectCommandsTokenTypeNVX and VkIndirectCommandsLayoutTokenNVX below for details.
The following code illustrates some of the key flags:
void cmdProcessAllSequences(cmd, objectTable, indirectCommandsLayout, pIndirectCommandsTokens, sequencesCount, indexbuffer, indexbufferoffset)
{
for (s = 0; s < sequencesCount; s++)
{
sequence = s;
if (indirectCommandsLayout.flags & VK_INDIRECT_COMMANDS_LAYOUT_USAGE_UNORDERED_SEQUENCES_BIT_NVX) {
sequence = incoherent_implementation_dependent_permutation[ sequence ];
}
if (indirectCommandsLayout.flags & VK_INDIRECT_COMMANDS_LAYOUT_USAGE_INDEXED_SEQUENCES_BIT_NVX) {
sequence = indexbuffer.load_uint32( sequence * sizeof(uint32_t) + indexbufferoffset);
}
cmdProcessSequence( cmd, objectTable, indirectCommandsLayout, pIndirectCommandsTokens, sequence );
}
}
Bits which can be set in
VkIndirectCommandsLayoutCreateInfoNVX::flags, specifying usage
hints of an indirect command layout, are:
typedef enum VkIndirectCommandsLayoutUsageFlagBitsNVX {
VK_INDIRECT_COMMANDS_LAYOUT_USAGE_UNORDERED_SEQUENCES_BIT_NVX = 0x00000001,
VK_INDIRECT_COMMANDS_LAYOUT_USAGE_SPARSE_SEQUENCES_BIT_NVX = 0x00000002,
VK_INDIRECT_COMMANDS_LAYOUT_USAGE_EMPTY_EXECUTIONS_BIT_NVX = 0x00000004,
VK_INDIRECT_COMMANDS_LAYOUT_USAGE_INDEXED_SEQUENCES_BIT_NVX = 0x00000008,
} VkIndirectCommandsLayoutUsageFlagBitsNVX;
-
VK_INDIRECT_COMMANDS_LAYOUT_USAGE_UNORDERED_SEQUENCES_BIT_NVXspecifies that the processing of sequences can happen at an implementation-dependent order, which is not guaranteed to be coherent across multiple invocations. -
VK_INDIRECT_COMMANDS_LAYOUT_USAGE_SPARSE_SEQUENCES_BIT_NVXspecifies that there is likely a high difference between allocated number of sequences and actually used. -
VK_INDIRECT_COMMANDS_LAYOUT_USAGE_EMPTY_EXECUTIONS_BIT_NVXspecifies that there are likely many draw or dispatch calls that are zero-sized (zero grid dimension, no primitives to render). -
VK_INDIRECT_COMMANDS_LAYOUT_USAGE_INDEXED_SEQUENCES_BIT_NVXspecifies that the input data for the sequences is not implicitly indexed from 0..sequencesUsed but a user providedVkBufferencoding the index is provided.
typedef VkFlags VkIndirectCommandsLayoutUsageFlagsNVX;
VkIndirectCommandsLayoutUsageFlagsNVX is a bitmask type for setting a
mask of zero or more VkIndirectCommandsLayoutUsageFlagBitsNVX.
Indirect command layouts are destroyed by:
void vkDestroyIndirectCommandsLayoutNVX(
VkDevice device,
VkIndirectCommandsLayoutNVX indirectCommandsLayout,
const VkAllocationCallbacks* pAllocator);
-
deviceis the logical device that destroys the layout. -
indirectCommandsLayoutis the table to destroy. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
28.4. Indirect Commands Generation
Command space for generated commands recorded into a secondary command buffer must be reserved by calling:
void vkCmdReserveSpaceForCommandsNVX(
VkCommandBuffer commandBuffer,
const VkCmdReserveSpaceForCommandsInfoNVX* pReserveSpaceInfo);
-
commandBufferis the secondary command buffer in which the space for device-generated commands is reserved. -
pProcessCommandsInfois a pointer to an instance of the vkCmdReserveSpaceForCommandsNVX structure containing parameters affecting the reservation of command buffer space.
typedef struct VkCmdReserveSpaceForCommandsInfoNVX {
VkStructureType sType;
const void* pNext;
VkObjectTableNVX objectTable;
VkIndirectCommandsLayoutNVX indirectCommandsLayout;
uint32_t maxSequencesCount;
} VkCmdReserveSpaceForCommandsInfoNVX;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
objectTableis theVkObjectTableNVXto be used for the generation process. Only registered objects at the time vkCmdReserveSpaceForCommandsNVX is called, will be taken into account for the reservation. -
indirectCommandsLayoutis theVkIndirectCommandsLayoutNVXthat must also be used at generation time. -
maxSequencesCountis the maximum number of sequences for which command buffer space will be reserved.
The generated commands will behave as if they were recorded within the call
to vkCmdReserveSpaceForCommandsNVX, that means they can inherit state
defined in the command buffer prior this call.
However, given the stateless nature of the generated sequences, they will
not affect commands after the reserved space.
Treat the state that can be affected by the provided
VkIndirectCommandsLayoutNVX as undefined.
The actual generation on the device is handled with:
void vkCmdProcessCommandsNVX(
VkCommandBuffer commandBuffer,
const VkCmdProcessCommandsInfoNVX* pProcessCommandsInfo);
-
commandBufferis the primary command buffer in which the generation process takes space. -
pProcessCommandsInfois a pointer to an instance of the VkCmdProcessCommandsInfoNVX structure containing parameters affecting the processing of commands.
typedef struct VkCmdProcessCommandsInfoNVX {
VkStructureType sType;
const void* pNext;
VkObjectTableNVX objectTable;
VkIndirectCommandsLayoutNVX indirectCommandsLayout;
uint32_t indirectCommandsTokenCount;
const VkIndirectCommandsTokenNVX* pIndirectCommandsTokens;
uint32_t maxSequencesCount;
VkCommandBuffer targetCommandBuffer;
VkBuffer sequencesCountBuffer;
VkDeviceSize sequencesCountOffset;
VkBuffer sequencesIndexBuffer;
VkDeviceSize sequencesIndexOffset;
} VkCmdProcessCommandsInfoNVX;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
objectTableis theVkObjectTableNVXto be used for the generation process. Only registered objects at the time vkCmdReserveSpaceForCommandsNVX is called, will be taken into account for the reservation. -
indirectCommandsLayoutis theVkIndirectCommandsLayoutNVXthat provides the command sequence to generate. -
indirectCommandsTokenCountdefines the number of input tokens used. -
pIndirectCommandsTokensprovides an array of VkIndirectCommandsTokenNVX that reference the input data for each token command. -
maxSequencesCountis the maximum number of sequences for which command buffer space will be reserved. IfsequencesCountBufferis VK_NULL_HANDLE, this is also the actual number of sequences generated. -
targetCommandBuffercan be the secondaryVkCommandBufferin which the commands should be recorded. IftargetCommandBufferisNULLan implicit reservation as well as execution takes place on the processingVkCommandBuffer. -
sequencesCountBuffercan beVkBufferfrom which the actual amount of sequences is sourced from asuint32_tvalue. -
sequencesCountOffsetis the byte offset intosequencesCountBufferwhere the count value is stored. -
sequencesIndexBuffermust be set ifindirectCommandsLayout’sVK_INDIRECT_COMMANDS_LAYOUT_USAGE_INDEXED_SEQUENCES_BITis set and provides the used sequence indices asuint32_tarray. Otherwise it must be VK_NULL_HANDLE. -
sequencesIndexOffsetis the byte offset intosequencesIndexBufferwhere the index values start.
Referencing the functions defined in Indirect Commands Layout,
vkCmdProcessCommandsNVX behaves as:
// For targetCommandBuffers the existing reservedSpace is reset & overwritten.
VkCommandBuffer cmd = targetCommandBuffer ?
targetCommandBuffer.reservedSpace :
commandBuffer;
uint32_t sequencesCount = sequencesCountBuffer ?
min(maxSequencesCount, sequencesCountBuffer.load_uint32(sequencesCountOffset) :
maxSequencesCount;
cmdProcessAllSequences(cmd, objectTable,
indirectCommandsLayout, pIndirectCommandsTokens,
sequencesCount,
sequencesIndexBuffer, sequencesIndexOffset);
// The stateful commands within indirectCommandsLayout will not
// affect the state of subsequent commands in the target
// command buffer (cmd)
|
Note
It is important to note that the state that may be affected through generated commands must be considered undefined for the commands following them. It is not possible to setup generated state and provoking work that uses this state outside of the generated sequence. |
29. Sparse Resources
As documented in Resource Memory Association,
VkBuffer and VkImage resources in Vulkan must be bound
completely and contiguously to a single VkDeviceMemory object.
This binding must be done before the resource is used, and the binding is
immutable for the lifetime of the resource.
Sparse resources relax these restrictions and provide these additional features:
-
Sparse resources can be bound non-contiguously to one or more
VkDeviceMemoryallocations. -
Sparse resources can be re-bound to different memory allocations over the lifetime of the resource.
-
Sparse resources can have descriptors generated and used orthogonally with memory binding commands.
29.1. Sparse Resource Features
Sparse resources have several features that must be enabled explicitly at
resource creation time.
The features are enabled by including bits in the flags parameter of
VkImageCreateInfo or VkBufferCreateInfo.
Each feature also has one or more corresponding feature enables specified in
VkPhysicalDeviceFeatures.
-
Sparse binding is the base feature, and provides the following capabilities:
-
Resources can be bound at some defined (sparse block) granularity.
-
The entire resource must be bound to memory before use regardless of regions actually accessed.
-
No specific mapping of image region to memory offset is defined, i.e. the location that each texel corresponds to in memory is implementation-dependent.
-
Sparse buffers have a well-defined mapping of buffer range to memory range, where an offset into a range of the buffer that is bound to a single contiguous range of memory corresponds to an identical offset within that range of memory.
-
Requested via the
VK_IMAGE_CREATE_SPARSE_BINDING_BITandVK_BUFFER_CREATE_SPARSE_BINDING_BITbits. -
A sparse image created using
VK_IMAGE_CREATE_SPARSE_BINDING_BIT(but notVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT) supports all formats that non-sparse usage supports, and supports bothVK_IMAGE_TILING_OPTIMALandVK_IMAGE_TILING_LINEARtiling.
-
-
Sparse Residency builds on (and requires) the
sparseBindingfeature. It includes the following capabilities:-
Resources do not have to be completely bound to memory before use on the device.
-
Images have a prescribed sparse image block layout, allowing specific rectangular regions of the image to be bound to specific offsets in memory allocations.
-
Consistency of access to unbound regions of the resource is defined by the absence or presence of
VkPhysicalDeviceSparseProperties::residencyNonResidentStrict. If this property is present, accesses to unbound regions of the resource are well defined and behave as if the data bound is populated with all zeros; writes are discarded. When this property is absent, accesses are considered safe, but reads will return undefined values. -
Requested via the
VK_IMAGE_CREATE_SPARSE_RESIDENCY_BITandVK_BUFFER_CREATE_SPARSE_RESIDENCY_BITbits. -
Sparse residency support is advertised on a finer grain via the following features:
-
sparseResidencyBuffer: Support for creatingVkBufferobjects with theVK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT. -
sparseResidencyImage2D: Support for creating 2D single-sampledVkImageobjects withVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT. -
sparseResidencyImage3D: Support for creating 3DVkImageobjects withVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT. -
sparseResidency2Samples: Support for creating 2DVkImageobjects with 2 samples andVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT. -
sparseResidency4Samples: Support for creating 2DVkImageobjects with 4 samples andVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT. -
sparseResidency8Samples: Support for creating 2DVkImageobjects with 8 samples andVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT. -
sparseResidency16Samples: Support for creating 2DVkImageobjects with 16 samples andVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT.
Implementations supporting
sparseResidencyImage2Dare only required to support sparse 2D, single-sampled images. Support for sparse 3D and MSAA images is optional and can be enabled viasparseResidencyImage3D,sparseResidency2Samples,sparseResidency4Samples,sparseResidency8Samples, andsparseResidency16Samples. -
-
A sparse image created using
VK_IMAGE_CREATE_SPARSE_RESIDENCY_BITsupports all non-compressed color formats with power-of-two element size that non-sparse usage supports. Additional formats may also be supported and can be queried via vkGetPhysicalDeviceSparseImageFormatProperties.VK_IMAGE_TILING_LINEARtiling is not supported.
-
-
Sparse aliasing provides the following capability that can be enabled per resource:
Allows physical memory ranges to be shared between multiple locations in the same sparse resource or between multiple sparse resources, with each binding of a memory location observing a consistent interpretation of the memory contents.
See Sparse Memory Aliasing for more information.
29.2. Sparse Buffers and Fully-Resident Images
Both VkBuffer and VkImage objects created with the
VK_IMAGE_CREATE_SPARSE_BINDING_BIT or
VK_BUFFER_CREATE_SPARSE_BINDING_BIT bits can be thought of as a
linear region of address space.
In the VkImage case if VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT is
not used, this linear region is entirely opaque, meaning that there is no
application-visible mapping between texel location and memory offset.
Unless VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT or
VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT are also used, the entire
resource must be bound to one or more VkDeviceMemory objects before
use.
29.2.1. Sparse Buffer and Fully-Resident Image Block Size
The sparse block size in bytes for sparse buffers and fully-resident images
is reported as VkMemoryRequirements::alignment.
alignment represents both the memory alignment requirement and the
binding granularity (in bytes) for sparse resources.
29.3. Sparse Partially-Resident Buffers
VkBuffer objects created with the
VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT bit allow the buffer to be made
only partially resident.
Partially resident VkBuffer objects are allocated and bound
identically to VkBuffer objects using only the
VK_BUFFER_CREATE_SPARSE_BINDING_BIT feature.
The only difference is the ability for some regions of the buffer to be
unbound during device use.
29.4. Sparse Partially-Resident Images
VkImage objects created with the
VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT bit allow specific rectangular
regions of the image called sparse image blocks to be bound to specific
ranges of memory.
This allows the application to manage residency at either image subresource
or sparse image block granularity.
Each image subresource (outside of the mip tail)
starts on a sparse block boundary and has dimensions that are integer
multiples of the corresponding dimensions of the sparse image block.
|
Note
Applications can use these types of images to control LOD based on total memory consumption. If memory pressure becomes an issue the application can unbind and disable specific mipmap levels of images without having to recreate resources or modify texel data of unaffected levels. The application can also use this functionality to access subregions of the image in a “megatexture” fashion. The application can create a large image and only populate the region of the image that is currently being used in the scene. |
29.4.1. Accessing Unbound Regions
The following member of VkPhysicalDeviceSparseProperties affects how
data in unbound regions of sparse resources are handled by the
implementation:
-
residencyNonResidentStrict
If this property is not present, reads of unbound regions of the image will return undefined values. Both reads and writes are still considered safe and will not affect other resources or populated regions of the image.
If this property is present, all reads of unbound regions of the image will behave as if the region was bound to memory populated with all zeros; writes will be discarded.
Formatted accesses to unbound memory may still alter some component values in the natural way for those accesses, e.g. substituting a value of one for alpha in formats that do not have an alpha component.
Example: Reading the alpha component of an unbacked VK_FORMAT_R8_UNORM
image will return a value of 1.0f.
See Physical Device Enumeration for instructions for retrieving physical device properties.
29.4.2. Mip Tail Regions
Sparse images created using VK_IMAGE_CREATE_SPARSE_BINDING_BIT
(without also using VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT) have no
specific mapping of image region or image subresource to memory offset
defined, so the entire image can be thought of as a linear opaque address
region.
However, images created with VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT do
have a prescribed sparse image block layout, and hence each image
subresource must start on a sparse block boundary.
Within each array layer, the set of mip levels that have a smaller size than
the sparse block size in bytes are grouped together into a mip tail
region.
If the VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT flag is present in
the flags member of VkSparseImageFormatProperties, for the
image’s format, then any mip level which has dimensions that are not
integer multiples of the corresponding dimensions of the sparse image block,
and all subsequent mip levels, are also included in the mip tail region.
The following member of VkPhysicalDeviceSparseProperties may affect
how the implementation places mip levels in the mip tail region:
-
residencyAlignedMipSize
Each mip tail region is bound to memory as an opaque region (i.e. must be bound using a VkSparseImageOpaqueMemoryBindInfo structure) and may be of a size greater than or equal to the sparse block size in bytes. This size is guaranteed to be an integer multiple of the sparse block size in bytes.
An implementation may choose to allow each array-layer’s mip tail region to
be bound to memory independently or require that all array-layer’s mip tail
regions be treated as one.
This is dictated by VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT in
VkSparseImageMemoryRequirements::flags.
The following diagrams depict how
VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT and
VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT alter memory usage and
requirements.
In the absence of VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT and
VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT, each array layer contains a
mip tail region containing texel data for all mip levels smaller than the
sparse image block in any dimension.
Mip levels that are as large or larger than a sparse image block in all dimensions can be bound individually. Right-edges and bottom-edges of each level are allowed to have partially used sparse blocks. Any bound partially-used-sparse-blocks must still have their full sparse block size in bytes allocated in memory.
When VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT is present all array
layers will share a single mip tail region.
|
Note
The mip tail regions are presented here in 2D arrays simply for figure size reasons. Each mip tail is logically a single array of sparse blocks with an implementation-dependent mapping of texels or compressed texel blocks to sparse blocks. |
When VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT is present the first
mip level that would contain partially used sparse blocks begins the mip
tail region.
This level and all subsequent levels are placed in the mip tail.
Only the first N mip levels whose dimensions are an exact multiple of
the sparse image block dimensions can be bound and unbound on a sparse
block basis.
|
Note
The mip tail region is presented here in a 2D array simply for figure size reasons. It is logically a single array of sparse blocks with an implementation-dependent mapping of texels or compressed texel blocks to sparse blocks. |
When both VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT and
VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT are present the constraints
from each of these flags are in effect.
29.4.3. Standard Sparse Image Block Shapes
Standard sparse image block shapes define a standard set of dimensions for sparse image blocks that depend on the format of the image. Layout of texels or compressed texel blocks within a sparse image block is implementation dependent. All currently defined standard sparse image block shapes are 64 KB in size.
For block-compressed formats (e.g. VK_FORMAT_BC5_UNORM_BLOCK), the
texel size is the size of the compressed texel block (e.g. 128-bit for
BC5) thus the dimensions of the standard sparse image block shapes
apply in terms of compressed texel blocks.
|
Note
For block-compressed formats, the dimensions of a sparse image block in terms of texels can be calculated by multiplying the sparse image block dimensions by the compressed texel block dimensions. |
| TEXEL SIZE (bits) | Block Shape (2D) | Block Shape (3D) |
|---|---|---|
8-Bit |
256 × 256 × 1 |
64 × 32 × 32 |
16-Bit |
256 × 128 × 1 |
32 × 32 × 32 |
32-Bit |
128 × 128 × 1 |
32 × 32 × 16 |
64-Bit |
128 × 64 × 1 |
32 × 16 × 16 |
128-Bit |
64 × 64 × 1 |
16 × 16 × 16 |
| TEXEL SIZE (bits) | Block Shape (2X) | Block Shape (4X) | Block Shape (8X) | Block Shape (16X) |
|---|---|---|---|---|
8-Bit |
128 × 256 × 1 |
128 × 128 × 1 |
64 × 128 × 1 |
64 × 64 × 1 |
16-Bit |
128 × 128 × 1 |
128 × 64 × 1 |
64 × 64 × 1 |
64 × 32 × 1 |
32-Bit |
64 × 128 × 1 |
64 × 64 × 1 |
32 × 64 × 1 |
32 × 32 × 1 |
64-Bit |
64 × 64 × 1 |
64 × 32 × 1 |
32 × 32 × 1 |
32 × 16 × 1 |
128-Bit |
32 × 64 × 1 |
32 × 32 × 1 |
16 × 32 × 1 |
16 × 16 × 1 |
Implementations that support the standard sparse image block shape for all
formats listed in the Standard Sparse Image Block Shapes (Single Sample) and
Standard Sparse Image Block Shapes (MSAA) tables may advertise the following
VkPhysicalDeviceSparseProperties:
-
residencyStandard2DBlockShape -
residencyStandard2DMultisampleBlockShape -
residencyStandard3DBlockShape
Reporting each of these features does not imply that all possible image types are supported as sparse. Instead, this indicates that no supported sparse image of the corresponding type will use custom sparse image block dimensions for any formats that have a corresponding standard sparse image block shape.
29.4.4. Custom Sparse Image Block Shapes
An implementation that does not support a standard image block shape for a
particular sparse partially-resident image may choose to support a custom
sparse image block shape for it instead.
The dimensions of such a custom sparse image block shape are reported in
VkSparseImageFormatProperties::imageGranularity.
As with standard sparse image block shapes, the size in bytes of the custom
sparse image block shape will be reported in
VkMemoryRequirements::alignment.
Custom sparse image block dimensions are reported through
vkGetPhysicalDeviceSparseImageFormatProperties and
vkGetImageSparseMemoryRequirements.
An implementation must not support both the standard sparse image block shape and a custom sparse image block shape for the same image. The standard sparse image block shape must be used if it is supported.
29.4.5. Multiple Aspects
Partially resident images are allowed to report separate sparse properties for different aspects of the image. One example is for depth/stencil images where the implementation separates the depth and stencil data into separate planes. Another reason for multiple aspects is to allow the application to manage memory allocation for implementation-private metadata associated with the image. See the figure below:
|
Note
The mip tail regions are presented here in 2D arrays simply for figure size reasons. Each mip tail is logically a single array of sparse blocks with an implementation-dependent mapping of texels or compressed texel blocks to sparse blocks. |
In the figure above the depth, stencil, and metadata aspects all have unique
sparse properties.
The per-texel stencil data is ¼ the size of the depth data,
hence the stencil sparse blocks include 4 × the number of
texels.
The sparse block size in bytes for all of the aspects is identical and
defined by VkMemoryRequirements::alignment.
Metadata
The metadata aspect of an image has the following constraints:
-
All metadata is reported in the mip tail region of the metadata aspect.
-
All metadata must be bound prior to device use of the sparse image.
29.5. Sparse Memory Aliasing
By default sparse resources have the same aliasing rules as non-sparse resources. See Memory Aliasing for more information.
VkDevice objects that have the
sparseResidencyAliased feature
enabled are able to use the VK_BUFFER_CREATE_SPARSE_ALIASED_BIT and
VK_IMAGE_CREATE_SPARSE_ALIASED_BIT flags for resource creation.
These flags allow resources to access physical memory bound into multiple
locations within one or more sparse resources in a data consistent
fashion.
This means that reading physical memory from multiple aliased locations will
return the same value.
Care must be taken when performing a write operation to aliased physical memory. Memory dependencies must be used to separate writes to one alias from reads or writes to another alias. Writes to aliased memory that are not properly guarded against accesses to different aliases will have undefined results for all accesses to the aliased memory.
Applications that wish to make use of data consistent sparse memory aliasing must abide by the following guidelines:
-
All sparse resources that are bound to aliased physical memory must be created with the
VK_BUFFER_CREATE_SPARSE_ALIASED_BIT/VK_IMAGE_CREATE_SPARSE_ALIASED_BITflag. -
All resources that access aliased physical memory must interpret the memory in the same way. This implies the following:
-
Buffers and images cannot alias the same physical memory in a data consistent fashion. The physical memory ranges must be used exclusively by buffers or used exclusively by images for data consistency to be guaranteed.
-
Memory in sparse image mip tail regions cannot access aliased memory in a data consistent fashion.
-
Sparse images that alias the same physical memory must have compatible formats and be using the same sparse image block shape in order to access aliased memory in a data consistent fashion.
-
Failure to follow any of the above guidelines will require the application to abide by the normal, non-sparse resource aliasing rules. In this case memory cannot be accessed in a data consistent fashion.
|
Note
Enabling sparse resource memory aliasing can be a way to lower physical memory use, but it may reduce performance on some implementations. An application developer can test on their target HW and balance the memory / performance trade-offs measured. |
29.6. Sparse Resource Implementation Guidelines
29.7. Sparse Resource API
The APIs related to sparse resources are grouped into the following categories:
29.7.1. Physical Device Features
Some sparse-resource related features are reported and enabled in
VkPhysicalDeviceFeatures.
These features must be supported and enabled on the VkDevice object
before applications can use them.
See Physical Device Features for information on how to
get and set enabled device features, and for more detailed explanations of
these features.
Sparse Physical Device Features
-
sparseBinding: Support for creatingVkBufferandVkImageobjects with theVK_BUFFER_CREATE_SPARSE_BINDING_BITandVK_IMAGE_CREATE_SPARSE_BINDING_BITflags, respectively. -
sparseResidencyBuffer: Support for creatingVkBufferobjects with theVK_BUFFER_CREATE_SPARSE_RESIDENCY_BITflag. -
sparseResidencyImage2D: Support for creating 2D single-sampledVkImageobjects withVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT. -
sparseResidencyImage3D: Support for creating 3DVkImageobjects withVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT. -
sparseResidency2Samples: Support for creating 2DVkImageobjects with 2 samples andVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT. -
sparseResidency4Samples: Support for creating 2DVkImageobjects with 4 samples andVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT. -
sparseResidency8Samples: Support for creating 2DVkImageobjects with 8 samples andVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT. -
sparseResidency16Samples: Support for creating 2DVkImageobjects with 16 samples andVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT. -
sparseResidencyAliased: Support for creatingVkBufferandVkImageobjects with theVK_BUFFER_CREATE_SPARSE_ALIASED_BITandVK_IMAGE_CREATE_SPARSE_ALIASED_BITflags, respectively.
29.7.2. Physical Device Sparse Properties
Some features of the implementation are not possible to disable, and are
reported to allow applications to alter their sparse resource usage
accordingly.
These read-only capabilities are reported in the
VkPhysicalDeviceProperties::sparseProperties member, which is a
structure of type VkPhysicalDeviceSparseProperties.
The VkPhysicalDeviceSparseProperties structure is defined as:
typedef struct VkPhysicalDeviceSparseProperties {
VkBool32 residencyStandard2DBlockShape;
VkBool32 residencyStandard2DMultisampleBlockShape;
VkBool32 residencyStandard3DBlockShape;
VkBool32 residencyAlignedMipSize;
VkBool32 residencyNonResidentStrict;
} VkPhysicalDeviceSparseProperties;
-
residencyStandard2DBlockShapeisVK_TRUEif the physical device will access all single-sample 2D sparse resources using the standard sparse image block shapes (based on image format), as described in the Standard Sparse Image Block Shapes (Single Sample) table. If this property is not supported the value returned in theimageGranularitymember of theVkSparseImageFormatPropertiesstructure for single-sample 2D images is not required to match the standard sparse image block dimensions listed in the table. -
residencyStandard2DMultisampleBlockShapeisVK_TRUEif the physical device will access all multisample 2D sparse resources using the standard sparse image block shapes (based on image format), as described in the Standard Sparse Image Block Shapes (MSAA) table. If this property is not supported, the value returned in theimageGranularitymember of theVkSparseImageFormatPropertiesstructure for multisample 2D images is not required to match the standard sparse image block dimensions listed in the table. -
residencyStandard3DBlockShapeisVK_TRUEif the physical device will access all 3D sparse resources using the standard sparse image block shapes (based on image format), as described in the Standard Sparse Image Block Shapes (Single Sample) table. If this property is not supported, the value returned in theimageGranularitymember of theVkSparseImageFormatPropertiesstructure for 3D images is not required to match the standard sparse image block dimensions listed in the table. -
residencyAlignedMipSizeisVK_TRUEif images with mip level dimensions that are not integer multiples of the corresponding dimensions of the sparse image block may be placed in the mip tail. If this property is not reported, only mip levels with dimensions smaller than theimageGranularitymember of theVkSparseImageFormatPropertiesstructure will be placed in the mip tail. If this property is reported the implementation is allowed to returnVK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BITin theflagsmember ofVkSparseImageFormatProperties, indicating that mip level dimensions that are not integer multiples of the corresponding dimensions of the sparse image block will be placed in the mip tail. -
residencyNonResidentStrictspecifies whether the physical device can consistently access non-resident regions of a resource. If this property isVK_TRUE, access to non-resident regions of resources will be guaranteed to return values as if the resource were populated with 0; writes to non-resident regions will be discarded.
29.7.3. Sparse Image Format Properties
Given that certain aspects of sparse image support, including the sparse image block dimensions, may be implementation-dependent, vkGetPhysicalDeviceSparseImageFormatProperties can be used to query for sparse image format properties prior to resource creation. This command is used to check whether a given set of sparse image parameters is supported and what the sparse image block shape will be.
Sparse Image Format Properties API
The VkSparseImageFormatProperties structure is defined as:
typedef struct VkSparseImageFormatProperties {
VkImageAspectFlags aspectMask;
VkExtent3D imageGranularity;
VkSparseImageFormatFlags flags;
} VkSparseImageFormatProperties;
-
aspectMaskis a bitmask VkImageAspectFlagBits specifying which aspects of the image the properties apply to. -
imageGranularityis the width, height, and depth of the sparse image block in texels or compressed texel blocks. -
flagsis a bitmask of VkSparseImageFormatFlagBits specifying additional information about the sparse resource.
Bits which can be set in VkSparseImageFormatProperties::flags,
specifying additional information about the sparse resource, are:
typedef enum VkSparseImageFormatFlagBits {
VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT = 0x00000001,
VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT = 0x00000002,
VK_SPARSE_IMAGE_FORMAT_NONSTANDARD_BLOCK_SIZE_BIT = 0x00000004,
} VkSparseImageFormatFlagBits;
-
VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BITspecifies that the image uses a single mip tail region for all array layers. -
VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BITspecifies that the first mip level whose dimensions are not integer multiples of the corresponding dimensions of the sparse image block begins the mip tail region. -
VK_SPARSE_IMAGE_FORMAT_NONSTANDARD_BLOCK_SIZE_BITspecifies that the image uses non-standard sparse image block dimensions, and theimageGranularityvalues do not match the standard sparse image block dimensions for the given format.
typedef VkFlags VkSparseImageFormatFlags;
VkSparseImageFormatFlags is a bitmask type for setting a mask of zero
or more VkSparseImageFormatFlagBits.
vkGetPhysicalDeviceSparseImageFormatProperties returns an array of
VkSparseImageFormatProperties.
Each element will describe properties for one set of image aspects that are
bound simultaneously in the image.
This is usually one element for each aspect in the image, but for
interleaved depth/stencil images there is only one element describing the
combined aspects.
void vkGetPhysicalDeviceSparseImageFormatProperties(
VkPhysicalDevice physicalDevice,
VkFormat format,
VkImageType type,
VkSampleCountFlagBits samples,
VkImageUsageFlags usage,
VkImageTiling tiling,
uint32_t* pPropertyCount,
VkSparseImageFormatProperties* pProperties);
-
physicalDeviceis the physical device from which to query the sparse image capabilities. -
formatis the image format. -
typeis the dimensionality of image. -
samplesis the number of samples per texel as defined in VkSampleCountFlagBits. -
usageis a bitmask describing the intended usage of the image. -
tilingis the tiling arrangement of the data elements in memory. -
pPropertyCountis a pointer to an integer related to the number of sparse format properties available or queried, as described below. -
pPropertiesis eitherNULLor a pointer to an array of VkSparseImageFormatProperties structures.
If pProperties is NULL, then the number of sparse format properties
available is returned in pPropertyCount.
Otherwise, pPropertyCount must point to a variable set by the user to
the number of elements in the pProperties array, and on return the
variable is overwritten with the number of structures actually written to
pProperties.
If pPropertyCount is less than the number of sparse format properties
available, at most pPropertyCount structures will be written.
If VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT is not supported for the given
arguments, pPropertyCount will be set to zero upon return, and no data
will be written to pProperties.
Multiple aspects are returned for depth/stencil images that are implemented
as separate planes by the implementation.
The depth and stencil data planes each have unique
VkSparseImageFormatProperties data.
Depth/stencil images with depth and stencil data interleaved into a single
plane will return a single VkSparseImageFormatProperties structure
with the aspectMask set to VK_IMAGE_ASPECT_DEPTH_BIT |
VK_IMAGE_ASPECT_STENCIL_BIT.
vkGetPhysicalDeviceSparseImageFormatProperties2 returns an array of
VkSparseImageFormatProperties2.
Each element will describe properties for one set of image aspects that are
bound simultaneously in the image.
This is usually one element for each aspect in the image, but for
interleaved depth/stencil images there is only one element describing the
combined aspects.
void vkGetPhysicalDeviceSparseImageFormatProperties2(
VkPhysicalDevice physicalDevice,
const VkPhysicalDeviceSparseImageFormatInfo2* pFormatInfo,
uint32_t* pPropertyCount,
VkSparseImageFormatProperties2* pProperties);
or the equivalent command
void vkGetPhysicalDeviceSparseImageFormatProperties2KHR(
VkPhysicalDevice physicalDevice,
const VkPhysicalDeviceSparseImageFormatInfo2* pFormatInfo,
uint32_t* pPropertyCount,
VkSparseImageFormatProperties2* pProperties);
-
physicalDeviceis the physical device from which to query the sparse image capabilities. -
pFormatInfois a pointer to a structure of type VkPhysicalDeviceSparseImageFormatInfo2 containing input parameters to the command. -
pPropertyCountis a pointer to an integer related to the number of sparse format properties available or queried, as described below. -
pPropertiesis eitherNULLor a pointer to an array of VkSparseImageFormatProperties2 structures.
vkGetPhysicalDeviceSparseImageFormatProperties2 behaves identically to
vkGetPhysicalDeviceSparseImageFormatProperties, with the ability to
return extended information by adding extension structures to the
pNext chain of its pProperties parameter.
The VkPhysicalDeviceSparseImageFormatInfo2 structure is defined as:
typedef struct VkPhysicalDeviceSparseImageFormatInfo2 {
VkStructureType sType;
const void* pNext;
VkFormat format;
VkImageType type;
VkSampleCountFlagBits samples;
VkImageUsageFlags usage;
VkImageTiling tiling;
} VkPhysicalDeviceSparseImageFormatInfo2;
or the equivalent
typedef VkPhysicalDeviceSparseImageFormatInfo2 VkPhysicalDeviceSparseImageFormatInfo2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
formatis the image format. -
typeis the dimensionality of image. -
samplesis the number of samples per texel as defined in VkSampleCountFlagBits. -
usageis a bitmask describing the intended usage of the image. -
tilingis the tiling arrangement of the data elements in memory.
The VkSparseImageFormatProperties2 structure is defined as:
typedef struct VkSparseImageFormatProperties2 {
VkStructureType sType;
void* pNext;
VkSparseImageFormatProperties properties;
} VkSparseImageFormatProperties2;
or the equivalent
typedef VkSparseImageFormatProperties2 VkSparseImageFormatProperties2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
propertiesis a structure of type VkSparseImageFormatProperties which is populated with the same values as in vkGetPhysicalDeviceSparseImageFormatProperties.
29.7.4. Sparse Resource Creation
Sparse resources require that one or more sparse feature flags be specified
(as part of the VkPhysicalDeviceFeatures structure described
previously in the Physical Device Features
section) at CreateDevice time.
When the appropriate device features are enabled, the
VK_BUFFER_CREATE_SPARSE_* and VK_IMAGE_CREATE_SPARSE_* flags
can be used.
See vkCreateBuffer and vkCreateImage for details of the resource
creation APIs.
|
Note
Specifying |
29.7.5. Sparse Resource Memory Requirements
Sparse resources have specific memory requirements related to binding sparse
memory.
These memory requirements are reported differently for VkBuffer
objects and VkImage objects.
Buffer and Fully-Resident Images
Buffers (both fully and partially resident) and fully-resident images can
be bound to memory using only the data from VkMemoryRequirements.
For all sparse resources the VkMemoryRequirements::alignment
member specifies both the bindable sparse block size in bytes and required
alignment of VkDeviceMemory.
Partially Resident Images
Partially resident images have a different method for binding memory.
As with buffers and fully resident images, the
VkMemoryRequirements::alignment field specifies the bindable
sparse block size in bytes for the image.
Requesting sparse memory requirements for VkImage objects using
vkGetImageSparseMemoryRequirements will return an array of one or more
VkSparseImageMemoryRequirements structures.
Each structure describes the sparse memory requirements for a group of
aspects of the image.
The sparse image must have been created using the
VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT flag to retrieve valid sparse
image memory requirements.
Sparse Image Memory Requirements
The VkSparseImageMemoryRequirements structure is defined as:
typedef struct VkSparseImageMemoryRequirements {
VkSparseImageFormatProperties formatProperties;
uint32_t imageMipTailFirstLod;
VkDeviceSize imageMipTailSize;
VkDeviceSize imageMipTailOffset;
VkDeviceSize imageMipTailStride;
} VkSparseImageMemoryRequirements;
-
formatProperties.aspectMaskis the set of aspects of the image that this sparse memory requirement applies to. This will usually have a single aspect specified. However, depth/stencil images may have depth and stencil data interleaved in the same sparse block, in which case bothVK_IMAGE_ASPECT_DEPTH_BITandVK_IMAGE_ASPECT_STENCIL_BITwould be present. -
formatProperties.imageGranularitydescribes the dimensions of a single bindable sparse image block in texel units. For aspectVK_IMAGE_ASPECT_METADATA_BIT, all dimensions will be zero. All metadata is located in the mip tail region. -
formatProperties.flagsis a bitmask of VkSparseImageFormatFlagBits:-
If
VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BITis set the image uses a single mip tail region for all array layers. -
If
VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BITis set the dimensions of mip levels must be integer multiples of the corresponding dimensions of the sparse image block for levels not located in the mip tail. -
If
VK_SPARSE_IMAGE_FORMAT_NONSTANDARD_BLOCK_SIZE_BITis set the image uses non-standard sparse image block dimensions. TheformatProperties.imageGranularityvalues do not match the standard sparse image block dimension corresponding to the image’s format.
-
-
imageMipTailFirstLodis the first mip level at which image subresources are included in the mip tail region. -
imageMipTailSizeis the memory size (in bytes) of the mip tail region. IfformatProperties.flagscontainsVK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT, this is the size of the whole mip tail, otherwise this is the size of the mip tail of a single array layer. This value is guaranteed to be a multiple of the sparse block size in bytes. -
imageMipTailOffsetis the opaque memory offset used with VkSparseImageOpaqueMemoryBindInfo to bind the mip tail region(s). -
imageMipTailStrideis the offset stride between each array-layer’s mip tail, ifformatProperties.flagsdoes not containVK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT(otherwise the value is undefined).
To query sparse memory requirements for an image, call:
void vkGetImageSparseMemoryRequirements(
VkDevice device,
VkImage image,
uint32_t* pSparseMemoryRequirementCount,
VkSparseImageMemoryRequirements* pSparseMemoryRequirements);
-
deviceis the logical device that owns the image. -
imageis theVkImageobject to get the memory requirements for. -
pSparseMemoryRequirementCountis a pointer to an integer related to the number of sparse memory requirements available or queried, as described below. -
pSparseMemoryRequirementsis eitherNULLor a pointer to an array ofVkSparseImageMemoryRequirementsstructures.
If pSparseMemoryRequirements is NULL, then the number of sparse
memory requirements available is returned in
pSparseMemoryRequirementCount.
Otherwise, pSparseMemoryRequirementCount must point to a variable set
by the user to the number of elements in the pSparseMemoryRequirements
array, and on return the variable is overwritten with the number of
structures actually written to pSparseMemoryRequirements.
If pSparseMemoryRequirementCount is less than the number of sparse
memory requirements available, at most pSparseMemoryRequirementCount
structures will be written.
If the image was not created with VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
then pSparseMemoryRequirementCount will be set to zero and
pSparseMemoryRequirements will not be written to.
|
Note
It is legal for an implementation to report a larger value in
|
To query sparse memory requirements for an image, call:
void vkGetImageSparseMemoryRequirements2(
VkDevice device,
const VkImageSparseMemoryRequirementsInfo2* pInfo,
uint32_t* pSparseMemoryRequirementCount,
VkSparseImageMemoryRequirements2* pSparseMemoryRequirements);
or the equivalent command
void vkGetImageSparseMemoryRequirements2KHR(
VkDevice device,
const VkImageSparseMemoryRequirementsInfo2* pInfo,
uint32_t* pSparseMemoryRequirementCount,
VkSparseImageMemoryRequirements2* pSparseMemoryRequirements);
-
deviceis the logical device that owns the image. -
pInfois a pointer to an instance of theVkImageSparseMemoryRequirementsInfo2structure containing parameters required for the memory requirements query. -
pSparseMemoryRequirementCountis a pointer to an integer related to the number of sparse memory requirements available or queried, as described below. -
pSparseMemoryRequirementsis eitherNULLor a pointer to an array ofVkSparseImageMemoryRequirements2structures.
The VkImageSparseMemoryRequirementsInfo2 structure is defined as:
typedef struct VkImageSparseMemoryRequirementsInfo2 {
VkStructureType sType;
const void* pNext;
VkImage image;
} VkImageSparseMemoryRequirementsInfo2;
or the equivalent
typedef VkImageSparseMemoryRequirementsInfo2 VkImageSparseMemoryRequirementsInfo2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
imageis the image to query.
The VkSparseImageMemoryRequirements2 structure is defined as:
typedef struct VkSparseImageMemoryRequirements2 {
VkStructureType sType;
void* pNext;
VkSparseImageMemoryRequirements memoryRequirements;
} VkSparseImageMemoryRequirements2;
or the equivalent
typedef VkSparseImageMemoryRequirements2 VkSparseImageMemoryRequirements2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
memoryRequirementsis a structure of type VkSparseImageMemoryRequirements describing the memory requirements of the sparse image.
29.7.6. Binding Resource Memory
Non-sparse resources are backed by a single physical allocation prior to
device use (via vkBindImageMemory or vkBindBufferMemory), and
their backing must not be changed.
On the other hand, sparse resources can be bound to memory non-contiguously
and these bindings can be altered during the lifetime of the resource.
|
Note
It is important to note that freeing a Implementations must ensure that no access to physical memory owned by the system or another process will occur in this scenario. In other words, accessing resources bound to freed memory may result in application termination, but must not result in system termination or in reading non-process-accessible memory. |
Sparse memory bindings execute on a queue that includes the
VK_QUEUE_SPARSE_BINDING_BIT bit.
Applications must use synchronization primitives to
guarantee that other queues do not access ranges of memory concurrently with
a binding change.
Accessing memory in a range while it is being rebound results in undefined
behavior.
It is valid to access other ranges of the same resource while a bind
operation is executing.
|
Note
Implementations must provide a guarantee that simultaneously binding sparse blocks while another queue accesses those same sparse blocks via a sparse resource must not access memory owned by another process or otherwise corrupt the system. |
While some implementations may include VK_QUEUE_SPARSE_BINDING_BIT
support in queue families that also include graphics and compute support,
other implementations may only expose a
VK_QUEUE_SPARSE_BINDING_BIT-only queue family.
In either case, applications must use synchronization
primitives to explicitly request any ordering dependencies between sparse
memory binding operations and other graphics/compute/transfer operations, as
sparse binding operations are not automatically ordered against command
buffer execution, even within a single queue.
When binding memory explicitly for the VK_IMAGE_ASPECT_METADATA_BIT
the application must use the VK_SPARSE_MEMORY_BIND_METADATA_BIT in
the VkSparseMemoryBind::flags field when binding memory.
Binding memory for metadata is done the same way as binding memory for the
mip tail, with the addition of the VK_SPARSE_MEMORY_BIND_METADATA_BIT
flag.
Binding the mip tail for any aspect must only be performed using
VkSparseImageOpaqueMemoryBindInfo.
If formatProperties.flags contains
VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT, then it can be bound with
a single VkSparseMemoryBind structure, with resourceOffset =
imageMipTailOffset and size = imageMipTailSize.
If formatProperties.flags does not contain
VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT then the offset for the mip
tail in each array layer is given as:
arrayMipTailOffset = imageMipTailOffset + arrayLayer * imageMipTailStride;
and the mip tail can be bound with layerCount VkSparseMemoryBind
structures, each using size = imageMipTailSize and
resourceOffset = arrayMipTailOffset as defined above.
Sparse memory binding is handled by the following APIs and related data structures.
Sparse Memory Binding Functions
The VkSparseMemoryBind structure is defined as:
typedef struct VkSparseMemoryBind {
VkDeviceSize resourceOffset;
VkDeviceSize size;
VkDeviceMemory memory;
VkDeviceSize memoryOffset;
VkSparseMemoryBindFlags flags;
} VkSparseMemoryBind;
-
resourceOffsetis the offset into the resource. -
sizeis the size of the memory region to be bound. -
memoryis theVkDeviceMemoryobject that the range of the resource is bound to. Ifmemoryis VK_NULL_HANDLE, the range is unbound. -
memoryOffsetis the offset into theVkDeviceMemoryobject to bind the resource range to. Ifmemoryis VK_NULL_HANDLE, this value is ignored. -
flagsis a bitmask of VkSparseMemoryBindFlagBits specifying usage of the binding operation.
The binding range [resourceOffset, resourceOffset +
size) has different constraints based on flags.
If flags contains VK_SPARSE_MEMORY_BIND_METADATA_BIT, the
binding range must be within the mip tail region of the metadata aspect.
This metadata region is defined by:
-
metadataRegion = [base, base +
imageMipTailSize) -
base =
imageMipTailOffset+imageMipTailStride× n
and imageMipTailOffset, imageMipTailSize, and
imageMipTailStride values are from the
VkSparseImageMemoryRequirements corresponding to the metadata aspect
of the image, and n is a valid array layer index for the image,
imageMipTailStride is considered to be zero for aspects where
VkSparseImageMemoryRequirements::formatProperties.flags contains
VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT.
If flags does not contain VK_SPARSE_MEMORY_BIND_METADATA_BIT,
the binding range must be within the range
[0,VkMemoryRequirements::size).
Bits which can be set in VkSparseMemoryBind::flags, specifying
usage of a sparse memory binding operation, are:
typedef enum VkSparseMemoryBindFlagBits {
VK_SPARSE_MEMORY_BIND_METADATA_BIT = 0x00000001,
} VkSparseMemoryBindFlagBits;
-
VK_SPARSE_MEMORY_BIND_METADATA_BITspecifies that the memory being bound is only for the metadata aspect.
typedef VkFlags VkSparseMemoryBindFlags;
VkSparseMemoryBindFlags is a bitmask type for setting a mask of zero
or more VkSparseMemoryBindFlagBits.
Memory is bound to VkBuffer objects created with the
VK_BUFFER_CREATE_SPARSE_BINDING_BIT flag using the following
structure:
typedef struct VkSparseBufferMemoryBindInfo {
VkBuffer buffer;
uint32_t bindCount;
const VkSparseMemoryBind* pBinds;
} VkSparseBufferMemoryBindInfo;
-
bufferis theVkBufferobject to be bound. -
bindCountis the number ofVkSparseMemoryBindstructures in thepBindsarray. -
pBindsis a pointer to array ofVkSparseMemoryBindstructures.
Memory is bound to opaque regions of VkImage objects created with the
VK_IMAGE_CREATE_SPARSE_BINDING_BIT flag using the following structure:
typedef struct VkSparseImageOpaqueMemoryBindInfo {
VkImage image;
uint32_t bindCount;
const VkSparseMemoryBind* pBinds;
} VkSparseImageOpaqueMemoryBindInfo;
-
imageis theVkImageobject to be bound. -
bindCountis the number ofVkSparseMemoryBindstructures in thepBindsarray. -
pBindsis a pointer to array ofVkSparseMemoryBindstructures.
|
Note
This operation is normally used to bind memory to fully-resident sparse images or for mip tail regions of partially resident images. However, it can also be used to bind memory for the entire binding range of partially resident images. In case When |
|
editing-note
(Jon) The preceding NOTE refers to |
Memory can be bound to sparse image blocks of VkImage objects created
with the VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT flag using the following
structure:
typedef struct VkSparseImageMemoryBindInfo {
VkImage image;
uint32_t bindCount;
const VkSparseImageMemoryBind* pBinds;
} VkSparseImageMemoryBindInfo;
-
imageis theVkImageobject to be bound -
bindCountis the number ofVkSparseImageMemoryBindstructures in pBinds array -
pBindsis a pointer to array ofVkSparseImageMemoryBindstructures
The VkSparseImageMemoryBind structure is defined as:
typedef struct VkSparseImageMemoryBind {
VkImageSubresource subresource;
VkOffset3D offset;
VkExtent3D extent;
VkDeviceMemory memory;
VkDeviceSize memoryOffset;
VkSparseMemoryBindFlags flags;
} VkSparseImageMemoryBind;
-
subresourceis the aspectMask and region of interest in the image. -
offsetare the coordinates of the first texel within the image subresource to bind. -
extentis the size in texels of the region within the image subresource to bind. The extent must be a multiple of the sparse image block dimensions, except when binding sparse image blocks along the edge of an image subresource it can instead be such that any coordinate ofoffset+extentequals the corresponding dimensions of the image subresource. -
memoryis theVkDeviceMemoryobject that the sparse image blocks of the image are bound to. Ifmemoryis VK_NULL_HANDLE, the sparse image blocks are unbound. -
memoryOffsetis an offset intoVkDeviceMemoryobject. Ifmemoryis VK_NULL_HANDLE, this value is ignored. -
flagsare sparse memory binding flags.
To submit sparse binding operations to a queue, call:
VkResult vkQueueBindSparse(
VkQueue queue,
uint32_t bindInfoCount,
const VkBindSparseInfo* pBindInfo,
VkFence fence);
-
queueis the queue that the sparse binding operations will be submitted to. -
bindInfoCountis the number of elements in thepBindInfoarray. -
pBindInfois an array of VkBindSparseInfo structures, each specifying a sparse binding submission batch. -
fenceis an optional handle to a fence to be signaled. Iffenceis not VK_NULL_HANDLE, it defines a fence signal operation.
vkQueueBindSparse is a queue submission
command, with each batch defined by an element of pBindInfo as an
instance of the VkBindSparseInfo structure.
Batches begin execution in the order they appear in pBindInfo, but
may complete out of order.
Within a batch, a given range of a resource must not be bound more than once. Across batches, if a range is to be bound to one allocation and offset and then to another allocation and offset, then the application must guarantee (usually using semaphores) that the binding operations are executed in the correct order, as well as to order binding operations against the execution of command buffer submissions.
As no operation to vkQueueBindSparse causes any pipeline stage to access memory, synchronization primitives used in this command effectively only define execution dependencies.
Additional information about fence and semaphore operation is described in the synchronization chapter.
The VkBindSparseInfo structure is defined as:
typedef struct VkBindSparseInfo {
VkStructureType sType;
const void* pNext;
uint32_t waitSemaphoreCount;
const VkSemaphore* pWaitSemaphores;
uint32_t bufferBindCount;
const VkSparseBufferMemoryBindInfo* pBufferBinds;
uint32_t imageOpaqueBindCount;
const VkSparseImageOpaqueMemoryBindInfo* pImageOpaqueBinds;
uint32_t imageBindCount;
const VkSparseImageMemoryBindInfo* pImageBinds;
uint32_t signalSemaphoreCount;
const VkSemaphore* pSignalSemaphores;
} VkBindSparseInfo;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
waitSemaphoreCountis the number of semaphores upon which to wait before executing the sparse binding operations for the batch. -
pWaitSemaphoresis a pointer to an array of semaphores upon which to wait on before the sparse binding operations for this batch begin execution. If semaphores to wait on are provided, they define a semaphore wait operation. -
bufferBindCountis the number of sparse buffer bindings to perform in the batch. -
pBufferBindsis a pointer to an array of VkSparseBufferMemoryBindInfo structures. -
imageOpaqueBindCountis the number of opaque sparse image bindings to perform. -
pImageOpaqueBindsis a pointer to an array of VkSparseImageOpaqueMemoryBindInfo structures, indicating opaque sparse image bindings to perform. -
imageBindCountis the number of sparse image bindings to perform. -
pImageBindsis a pointer to an array of VkSparseImageMemoryBindInfo structures, indicating sparse image bindings to perform. -
signalSemaphoreCountis the number of semaphores to be signaled once the sparse binding operations specified by the structure have completed execution. -
pSignalSemaphoresis a pointer to an array of semaphores which will be signaled when the sparse binding operations for this batch have completed execution. If semaphores to be signaled are provided, they define a semaphore signal operation.
If the pNext chain of VkBindSparseInfo includes a
VkDeviceGroupBindSparseInfo structure, then that structure includes
device indices specifying which instance of the resources and memory are
bound.
The VkDeviceGroupBindSparseInfo structure is defined as:
typedef struct VkDeviceGroupBindSparseInfo {
VkStructureType sType;
const void* pNext;
uint32_t resourceDeviceIndex;
uint32_t memoryDeviceIndex;
} VkDeviceGroupBindSparseInfo;
or the equivalent
typedef VkDeviceGroupBindSparseInfo VkDeviceGroupBindSparseInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
resourceDeviceIndexis a device index indicating which instance of the resource is bound. -
memoryDeviceIndexis a device index indicating which instance of the memory the resource instance is bound to.
These device indices apply to all buffer and image memory binds included in
the batch that points to this structure.
The semaphore waits and signals for the batch are executed only by the
physical device specified by the resourceDeviceIndex.
If this structure is not present, resourceDeviceIndex and
memoryDeviceIndex are assumed to be zero.
29.8. Examples
The following examples illustrate basic creation of sparse images and binding them to physical memory.
29.8.1. Basic Sparse Resources
This basic example creates a normal VkImage object but uses
fine-grained memory allocation to back the resource with multiple memory
ranges.
VkDevice device;
VkQueue queue;
VkImage sparseImage;
VkAllocationCallbacks* pAllocator = NULL;
VkMemoryRequirements memoryRequirements = {};
VkDeviceSize offset = 0;
VkSparseMemoryBind binds[MAX_CHUNKS] = {}; // MAX_CHUNKS is NOT part of Vulkan
uint32_t bindCount = 0;
// ...
// Allocate image object
const VkImageCreateInfo sparseImageInfo =
{
VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO, // sType
NULL, // pNext
VK_IMAGE_CREATE_SPARSE_BINDING_BIT | ..., // flags
...
};
vkCreateImage(device, &sparseImageInfo, pAllocator, &sparseImage);
// Get memory requirements
vkGetImageMemoryRequirements(
device,
sparseImage,
&memoryRequirements);
// Bind memory in fine-grained fashion, find available memory ranges
// from potentially multiple VkDeviceMemory pools.
// (Illustration purposes only, can be optimized for perf)
while (memoryRequirements.size && bindCount < MAX_CHUNKS)
{
VkSparseMemoryBind* pBind = &binds[bindCount];
pBind->resourceOffset = offset;
AllocateOrGetMemoryRange(
device,
&memoryRequirements,
&pBind->memory,
&pBind->memoryOffset,
&pBind->size);
// memory ranges must be sized as multiples of the alignment
assert(IsMultiple(pBind->size, memoryRequirements.alignment));
assert(IsMultiple(pBind->memoryOffset, memoryRequirements.alignment));
memoryRequirements.size -= pBind->size;
offset += pBind->size;
bindCount++;
}
// Ensure all image has backing
if (memoryRequirements.size)
{
// Error condition - too many chunks
}
const VkSparseImageOpaqueMemoryBindInfo opaqueBindInfo =
{
sparseImage, // image
bindCount, // bindCount
binds // pBinds
};
const VkBindSparseInfo bindSparseInfo =
{
VK_STRUCTURE_TYPE_BIND_SPARSE_INFO, // sType
NULL, // pNext
...
1, // imageOpaqueBindCount
&opaqueBindInfo, // pImageOpaqueBinds
...
};
// vkQueueBindSparse is externally synchronized per queue object.
AcquireQueueOwnership(queue);
// Actually bind memory
vkQueueBindSparse(queue, 1, &bindSparseInfo, VK_NULL_HANDLE);
ReleaseQueueOwnership(queue);
29.8.2. Advanced Sparse Resources
This more advanced example creates an arrayed color attachment / texture image and binds only LOD zero and the required metadata to physical memory.
VkDevice device;
VkQueue queue;
VkImage sparseImage;
VkAllocationCallbacks* pAllocator = NULL;
VkMemoryRequirements memoryRequirements = {};
uint32_t sparseRequirementsCount = 0;
VkSparseImageMemoryRequirements* pSparseReqs = NULL;
VkSparseMemoryBind binds[MY_IMAGE_ARRAY_SIZE] = {};
VkSparseImageMemoryBind imageBinds[MY_IMAGE_ARRAY_SIZE] = {};
uint32_t bindCount = 0;
// Allocate image object (both renderable and sampleable)
const VkImageCreateInfo sparseImageInfo =
{
VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO, // sType
NULL, // pNext
VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT | ..., // flags
...
VK_FORMAT_R8G8B8A8_UNORM, // format
...
MY_IMAGE_ARRAY_SIZE, // arrayLayers
...
VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT |
VK_IMAGE_USAGE_SAMPLED_BIT, // usage
...
};
vkCreateImage(device, &sparseImageInfo, pAllocator, &sparseImage);
// Get memory requirements
vkGetImageMemoryRequirements(
device,
sparseImage,
&memoryRequirements);
// Get sparse image aspect properties
vkGetImageSparseMemoryRequirements(
device,
sparseImage,
&sparseRequirementsCount,
NULL);
pSparseReqs = (VkSparseImageMemoryRequirements*)
malloc(sparseRequirementsCount * sizeof(VkSparseImageMemoryRequirements));
vkGetImageSparseMemoryRequirements(
device,
sparseImage,
&sparseRequirementsCount,
pSparseReqs);
// Bind LOD level 0 and any required metadata to memory
for (uint32_t i = 0; i < sparseRequirementsCount; ++i)
{
if (pSparseReqs[i].formatProperties.aspectMask &
VK_IMAGE_ASPECT_METADATA_BIT)
{
// Metadata must not be combined with other aspects
assert(pSparseReqs[i].formatProperties.aspectMask ==
VK_IMAGE_ASPECT_METADATA_BIT);
if (pSparseReqs[i].formatProperties.flags &
VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT)
{
VkSparseMemoryBind* pBind = &binds[bindCount];
pBind->memorySize = pSparseReqs[i].imageMipTailSize;
bindCount++;
// ... Allocate memory range
pBind->resourceOffset = pSparseReqs[i].imageMipTailOffset;
pBind->memoryOffset = /* allocated memoryOffset */;
pBind->memory = /* allocated memory */;
pBind->flags = VK_SPARSE_MEMORY_BIND_METADATA_BIT;
}
else
{
// Need a mip tail region per array layer.
for (uint32_t a = 0; a < sparseImageInfo.arrayLayers; ++a)
{
VkSparseMemoryBind* pBind = &binds[bindCount];
pBind->memorySize = pSparseReqs[i].imageMipTailSize;
bindCount++;
// ... Allocate memory range
pBind->resourceOffset = pSparseReqs[i].imageMipTailOffset +
(a * pSparseReqs[i].imageMipTailStride);
pBind->memoryOffset = /* allocated memoryOffset */;
pBind->memory = /* allocated memory */
pBind->flags = VK_SPARSE_MEMORY_BIND_METADATA_BIT;
}
}
}
else
{
// resource data
VkExtent3D lod0BlockSize =
{
AlignedDivide(
sparseImageInfo.extent.width,
pSparseReqs[i].formatProperties.imageGranularity.width);
AlignedDivide(
sparseImageInfo.extent.height,
pSparseReqs[i].formatProperties.imageGranularity.height);
AlignedDivide(
sparseImageInfo.extent.depth,
pSparseReqs[i].formatProperties.imageGranularity.depth);
}
size_t totalBlocks =
lod0BlockSize.width *
lod0BlockSize.height *
lod0BlockSize.depth;
// Each block is the same size as the alignment requirement,
// calculate total memory size for level 0
VkDeviceSize lod0MemSize = totalBlocks * memoryRequirements.alignment;
// Allocate memory for each array layer
for (uint32_t a = 0; a < sparseImageInfo.arrayLayers; ++a)
{
// ... Allocate memory range
VkSparseImageMemoryBind* pBind = &imageBinds[a];
pBind->subresource.aspectMask = pSparseReqs[i].formatProperties.aspectMask;
pBind->subresource.mipLevel = 0;
pBind->subresource.arrayLayer = a;
pBind->offset = (VkOffset3D){0, 0, 0};
pBind->extent = sparseImageInfo.extent;
pBind->memoryOffset = /* allocated memoryOffset */;
pBind->memory = /* allocated memory */;
pBind->flags = 0;
}
}
free(pSparseReqs);
}
const VkSparseImageOpaqueMemoryBindInfo opaqueBindInfo =
{
sparseImage, // image
bindCount, // bindCount
binds // pBinds
};
const VkSparseImageMemoryBindInfo imageBindInfo =
{
sparseImage, // image
sparseImageInfo.arrayLayers, // bindCount
imageBinds // pBinds
};
const VkBindSparseInfo bindSparseInfo =
{
VK_STRUCTURE_TYPE_BIND_SPARSE_INFO, // sType
NULL, // pNext
...
1, // imageOpaqueBindCount
&opaqueBindInfo, // pImageOpaqueBinds
1, // imageBindCount
&imageBindInfo, // pImageBinds
...
};
// vkQueueBindSparse is externally synchronized per queue object.
AcquireQueueOwnership(queue);
// Actually bind memory
vkQueueBindSparse(queue, 1, &bindSparseInfo, VK_NULL_HANDLE);
ReleaseQueueOwnership(queue);
30. Window System Integration (WSI)
This chapter discusses the window system integration (WSI) between the Vulkan API and the various forms of displaying the results of rendering to a user. Since the Vulkan API can be used without displaying results, WSI is provided through the use of optional Vulkan extensions. This chapter provides an overview of WSI. See the appendix for additional details of each WSI extension, including which extensions must be enabled in order to use each of the functions described in this chapter.
30.1. WSI Platform
A platform is an abstraction for a window system, OS, etc. Some examples include MS Windows, Android, and Wayland. The Vulkan API may be integrated in a unique manner for each platform.
The Vulkan API does not define any type of platform object. Platform-specific WSI extensions are defined, which contain platform-specific functions for using WSI. Use of these extensions is guarded by preprocessor symbols as defined in the Window System-Specific Header Control appendix.
In order for an application to be compiled to use WSI with a given platform, it must either:
-
#define the appropriate preprocessor symbol prior to including the
vulkan.hheader file, or -
include
vulkan_core.hand any native platform headers, followed by the appropriate platform-specific header.
The preprocessor symbols and platform-specific headers are defined in the Window System Extensions and Headers table.
Each platform-specific extension is an instance extension.
The application must enable instance extensions with vkCreateInstance
before using them.
30.2. WSI Surface
Native platform surface or window objects are abstracted by surface objects,
which are represented by VkSurfaceKHR handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkSurfaceKHR)
The VK_KHR_surface extension declares the VkSurfaceKHR object, and
provides a function for destroying VkSurfaceKHR objects.
Separate platform-specific extensions each provide a function for creating a
VkSurfaceKHR object for the respective platform.
From the application’s perspective this is an opaque handle, just like the
handles of other Vulkan objects.
|
Note
On certain platforms, the Vulkan loader and ICDs may have conventions that
treat the handle as a pointer to a struct that contains the
platform-specific information about the surface.
This will be described in the documentation for the loader-ICD interface,
and in the |
|
editing-note
TODO: Consider replacing the above note editing note with a pointer to the loader spec when it exists. However, the information is not relevant to users of the API nor does it affect conformance of a Vulkan implementation to this spec. |
30.2.1. Android Platform
To create a VkSurfaceKHR object for an Android native window, call:
VkResult vkCreateAndroidSurfaceKHR(
VkInstance instance,
const VkAndroidSurfaceCreateInfoKHR* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkSurfaceKHR* pSurface);
-
instanceis the instance to associate the surface with. -
pCreateInfois a pointer to an instance of theVkAndroidSurfaceCreateInfoKHRstructure containing parameters affecting the creation of the surface object. -
pAllocatoris the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation). -
pSurfacepoints to aVkSurfaceKHRhandle in which the created surface object is returned.
During the lifetime of a surface created using a particular
ANativeWindow handle any attempts to create another surface for the
same ANativeWindow and any attempts to connect to the same
ANativeWindow through other platform mechanisms will fail.
|
Note
In particular, only one |
If successful, vkCreateAndroidSurfaceKHR increments the
ANativeWindow’s reference count, and vkDestroySurfaceKHR will
decrement it.
On Android, when a swapchain’s imageExtent does not match the
surface’s currentExtent, the presentable images will be scaled to the
surface’s dimensions during presentation.
minImageExtent is (1,1), and maxImageExtent is the maximum
image size supported by the consumer.
For the system compositor, currentExtent is the window size (i.e. the
consumer’s preferred size).
The VkAndroidSurfaceCreateInfoKHR structure is defined as:
typedef struct VkAndroidSurfaceCreateInfoKHR {
VkStructureType sType;
const void* pNext;
VkAndroidSurfaceCreateFlagsKHR flags;
struct ANativeWindow* window;
} VkAndroidSurfaceCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
windowis a pointer to theANativeWindowto associate the surface with.
30.2.2. Mir Platform
To create a VkSurfaceKHR object for a Mir window, call:
VkResult vkCreateMirSurfaceKHR(
VkInstance instance,
const VkMirSurfaceCreateInfoKHR* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkSurfaceKHR* pSurface);
-
instanceis the instance to associate the surface with. -
pCreateInfois a pointer to an instance of the VkMirSurfaceCreateInfoKHR structure containing parameters affecting the creation of the surface object. -
pAllocatoris the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation). -
pSurfacepoints to aVkSurfaceKHRhandle in which the created surface object is returned.
The VkMirSurfaceCreateInfoKHR structure is defined as:
typedef struct VkMirSurfaceCreateInfoKHR {
VkStructureType sType;
const void* pNext;
VkMirSurfaceCreateFlagsKHR flags;
MirConnection* connection;
MirSurface* mirSurface;
} VkMirSurfaceCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
connectionandsurfaceare pointers to theMirConnectionandMirSurfacefor the window to associate the surface with.
On Mir, when a swapchain’s imageExtent does not match the surface’s
currentExtent, the presentable images will be scaled to the surface’s
dimensions during presentation.
minImageExtent is (1,1), and maxImageExtent is the maximum
supported surface size.
30.2.3. Wayland Platform
To create a VkSurfaceKHR object for a Wayland surface, call:
VkResult vkCreateWaylandSurfaceKHR(
VkInstance instance,
const VkWaylandSurfaceCreateInfoKHR* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkSurfaceKHR* pSurface);
-
instanceis the instance to associate the surface with. -
pCreateInfois a pointer to an instance of the VkWaylandSurfaceCreateInfoKHR structure containing parameters affecting the creation of the surface object. -
pAllocatoris the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation). -
pSurfacepoints to aVkSurfaceKHRhandle in which the created surface object is returned.
The VkWaylandSurfaceCreateInfoKHR structure is defined as:
typedef struct VkWaylandSurfaceCreateInfoKHR {
VkStructureType sType;
const void* pNext;
VkWaylandSurfaceCreateFlagsKHR flags;
struct wl_display* display;
struct wl_surface* surface;
} VkWaylandSurfaceCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
displayandsurfaceare pointers to the Waylandwl_displayandwl_surfaceto associate the surface with.
On Wayland, currentExtent is undefined (0xFFFFFFFF, 0xFFFFFFFF).
Whatever the application sets a swapchain’s imageExtent to will be the
size of the window, after the first image is presented.
minImageExtent is (1,1), and maxImageExtent is the maximum
supported surface size.
Any calls to vkGetPhysicalDeviceSurfacePresentModesKHR on a surface
created with vkCreateWaylandSurfaceKHR are required to return
VK_PRESENT_MODE_MAILBOX_KHR as one of the valid present modes.
Some Vulkan functions may send protocol over the specified wl_display
connection when using a swapchain or presentable images created from a
VkSurfaceKHR referring to a wl_surface.
Applications must therefore ensure that both the wl_display and the
wl_surface remain valid for the lifetime of any VkSwapchainKHR
objects created from a particular wl_display and wl_surface.
Also, calling vkQueuePresentKHR will result in Vulkan sending
wl_surface.commit requests to the underlying wl_surface of each
VkSwapchainKHR objects referenced by pPresentInfo.
If the swapchain is created with a present mode of
VK_PRESENT_MODE_MAILBOX_KHR or VK_PRESENT_MODE_IMMEDIATE_KHR,
then the corresponding wl_surface.attach, wl_surface.damage, and
wl_surface.commit request must be issued by the implementation during
the call to vkQueuePresentKHR and must not be issued by the
implementation outside of vkQueuePresentKHR.
This ensures that any Wayland requests sent by the client after the call to
vkQueuePresentKHR returns will be received by the compositor after the
wl_surface.commit.
Regardless of the mode of swapchain creation, a new wl_event_queue
must be created for each successful vkCreateWaylandSurfaceKHR call,
and every Wayland object created by the implementation must be assigned to
this event queue.
If the platform provides Wayland 1.11 or greater, this must be implemented
by the use of Wayland proxy object wrappers, to avoid race conditions.
If the application wishes to synchronize any window changes with a
particular frame, such requests must be sent to the Wayland display server
prior to calling vkQueuePresentKHR.
For full control over interactions between Vulkan rendering and other
Wayland protocol requests and events, a present mode of
VK_PRESENT_MODE_MAILBOX_KHR should be used.
30.2.4. Win32 Platform
To create a VkSurfaceKHR object for a Win32 window, call:
VkResult vkCreateWin32SurfaceKHR(
VkInstance instance,
const VkWin32SurfaceCreateInfoKHR* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkSurfaceKHR* pSurface);
-
instanceis the instance to associate the surface with. -
pCreateInfois a pointer to an instance of theVkWin32SurfaceCreateInfoKHRstructure containing parameters affecting the creation of the surface object. -
pAllocatoris the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation). -
pSurfacepoints to aVkSurfaceKHRhandle in which the created surface object is returned.
The VkWin32SurfaceCreateInfoKHR structure is defined as:
typedef struct VkWin32SurfaceCreateInfoKHR {
VkStructureType sType;
const void* pNext;
VkWin32SurfaceCreateFlagsKHR flags;
HINSTANCE hinstance;
HWND hwnd;
} VkWin32SurfaceCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
hinstanceandhwndare the Win32HINSTANCEandHWNDfor the window to associate the surface with.
With Win32, minImageExtent, maxImageExtent, and
currentExtent must always equal the window size.
The currentExtent of a Win32 surface must have both width and
height greater than 0, or both of them 0.
|
Note
Due to above restrictions, it is only possible to create a new swapchain on
this platform with The window size may become (0, 0) on this platform (e.g. when the window is minimized), and so a swapchain cannot be created until the size changes. |
30.2.5. XCB Platform
To create a VkSurfaceKHR object for an X11 window, using the XCB
client-side library, call:
VkResult vkCreateXcbSurfaceKHR(
VkInstance instance,
const VkXcbSurfaceCreateInfoKHR* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkSurfaceKHR* pSurface);
-
instanceis the instance to associate the surface with. -
pCreateInfois a pointer to an instance of theVkXcbSurfaceCreateInfoKHRstructure containing parameters affecting the creation of the surface object. -
pAllocatoris the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation). -
pSurfacepoints to aVkSurfaceKHRhandle in which the created surface object is returned.
The VkXcbSurfaceCreateInfoKHR structure is defined as:
typedef struct VkXcbSurfaceCreateInfoKHR {
VkStructureType sType;
const void* pNext;
VkXcbSurfaceCreateFlagsKHR flags;
xcb_connection_t* connection;
xcb_window_t window;
} VkXcbSurfaceCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
connectionis a pointer to anxcb_connection_tto the X server. -
windowis thexcb_window_tfor the X11 window to associate the surface with.
With Xcb, minImageExtent, maxImageExtent, and
currentExtent must always equal the window size.
The currentExtent of an Xcb surface must have both width and
height greater than 0, or both of them 0.
|
Note
Due to above restrictions, it is only possible to create a new swapchain on
this platform with The window size may become (0, 0) on this platform (e.g. when the window is minimized), and so a swapchain cannot be created until the size changes. |
Some Vulkan functions may send protocol over the specified xcb connection when using a swapchain or presentable images created from a VkSurfaceKHR referring to an xcb window. Applications must therefore ensure the xcb connection is available to Vulkan for the duration of any functions that manipulate such swapchains or their presentable images, and any functions that build or queue command buffers that operate on such presentable images. Specifically, applications using Vulkan with xcb-based swapchains must
-
Avoid holding a server grab on an xcb connection while waiting for Vulkan operations to complete using a swapchain derived from a different xcb connection referring to the same X server instance. Failing to do so may result in deadlock.
30.2.6. Xlib Platform
To create a VkSurfaceKHR object for an X11 window, using the Xlib
client-side library, call:
VkResult vkCreateXlibSurfaceKHR(
VkInstance instance,
const VkXlibSurfaceCreateInfoKHR* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkSurfaceKHR* pSurface);
-
instanceis the instance to associate the surface with. -
pCreateInfois a pointer to an instance of theVkXlibSurfaceCreateInfoKHRstructure containing the parameters affecting the creation of the surface object. -
pAllocatoris the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation). -
pSurfacepoints to aVkSurfaceKHRhandle in which the created surface object is returned.
The VkXlibSurfaceCreateInfoKHR structure is defined as:
typedef struct VkXlibSurfaceCreateInfoKHR {
VkStructureType sType;
const void* pNext;
VkXlibSurfaceCreateFlagsKHR flags;
Display* dpy;
Window window;
} VkXlibSurfaceCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
dpyis a pointer to an XlibDisplayconnection to the X server. -
windowis an XlibWindowto associate the surface with.
With Xlib, minImageExtent, maxImageExtent, and
currentExtent must always equal the window size.
The currentExtent of an Xlib surface must have both width and
height greater than 0, or both of them 0.
|
Note
Due to above restrictions, it is only possible to create a new swapchain on
this platform with The window size may become (0, 0) on this platform (e.g. when the window is minimized), and so a swapchain cannot be created until the size changes. |
Some Vulkan functions may send protocol over the specified Xlib
Display connection when using a swapchain or presentable images created
from a VkSurfaceKHR referring to an Xlib window.
Applications must therefore ensure the display connection is available to
Vulkan for the duration of any functions that manipulate such swapchains or
their presentable images, and any functions that build or queue command
buffers that operate on such presentable images.
Specifically, applications using Vulkan with Xlib-based swapchains must
-
Avoid holding a server grab on a display connection while waiting for Vulkan operations to complete using a swapchain derived from a different display connection referring to the same X server instance. Failing to do so may result in deadlock.
Some implementations may require threads to implement some presentation
modes so applications must call XInitThreads() before calling any
other Xlib functions.
30.2.7. iOS Platform
To create a VkSurfaceKHR object for an iOS UIView, call:
VkResult vkCreateIOSSurfaceMVK(
VkInstance instance,
const VkIOSSurfaceCreateInfoMVK* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkSurfaceKHR* pSurface);
-
instanceis the instance with which to associate the surface. -
pCreateInfois a pointer to an instance of the VkIOSSurfaceCreateInfoMVK structure containing parameters affecting the creation of the surface object. -
pAllocatoris the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation). -
pSurfacepoints to aVkSurfaceKHRhandle in which the created surface object is returned.
The VkIOSSurfaceCreateInfoMVK structure is defined as:
typedef struct VkIOSSurfaceCreateInfoMVK {
VkStructureType sType;
const void* pNext;
VkIOSSurfaceCreateFlagsMVK flags;
const void* pView;
} VkIOSSurfaceCreateInfoMVK;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
pViewis a reference to aUIViewobject which will display this surface. ThisUIViewmust be backed by aCALayerinstance of typeCAMetalLayer.
30.2.8. macOS Platform
To create a VkSurfaceKHR object for a macOS NSView, call:
VkResult vkCreateMacOSSurfaceMVK(
VkInstance instance,
const VkMacOSSurfaceCreateInfoMVK* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkSurfaceKHR* pSurface);
-
instanceis the instance with which to associate the surface. -
pCreateInfois a pointer to an instance of the VkMacOSSurfaceCreateInfoMVK structure containing parameters affecting the creation of the surface object. -
pAllocatoris the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation). -
pSurfacepoints to aVkSurfaceKHRhandle in which the created surface object is returned.
The VkMacOSSurfaceCreateInfoMVK structure is defined as:
typedef struct VkMacOSSurfaceCreateInfoMVK {
VkStructureType sType;
const void* pNext;
VkMacOSSurfaceCreateFlagsMVK flags;
const void* pView;
} VkMacOSSurfaceCreateInfoMVK;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
pViewis a reference to aNSViewobject which will display this surface. ThisNSViewmust be backed by aCALayerinstance of typeCAMetalLayer.
30.2.9. VI Platform
To create a VkSurfaceKHR object for an nn::vi::Layer,
query the layer’s native handle using
nn::vi::GetNativeWindow, and then call:
VkResult vkCreateViSurfaceNN(
VkInstance instance,
const VkViSurfaceCreateInfoNN* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkSurfaceKHR* pSurface);
-
instanceis the instance with which to associate the surface. -
pCreateInfois a pointer to an instance of theVkViSurfaceCreateInfoNNstructure containing parameters affecting the creation of the surface object. -
pAllocatoris the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation). -
pSurfacepoints to aVkSurfaceKHRhandle in which the created surface object is returned.
During the lifetime of a surface created using a particular
nn::vi::NativeWindowHandle any attempts to create another
surface for the same nn::vi::Layer and any attempts to
connect to the same nn::vi::Layer through other platform
mechanisms will have undefined results.
The currentExtent of a VI surface is always undefined.
Applications are expected to choose an appropriate size for the swapchain’s
imageExtent (e.g., by matching the the result of a call to
nn::vi::GetDisplayResolution).
The VkViSurfaceCreateInfoNN structure is defined as:
typedef struct VkViSurfaceCreateInfoNN {
VkStructureType sType;
const void* pNext;
VkViSurfaceCreateFlagsNN flags;
void* window;
} VkViSurfaceCreateInfoNN;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use. -
windowis thenn::vi::NativeWindowHandlefor thenn::vi::Layerwith which to associate the surface.
30.2.10. Platform-Independent Information
Once created, VkSurfaceKHR objects can be used in this and other
extensions, in particular the VK_KHR_swapchain extension.
Several WSI functions return VK_ERROR_SURFACE_LOST_KHR if the surface
becomes no longer available.
After such an error, the surface (and any child swapchain, if one exists)
should be destroyed, as there is no way to restore them to a not-lost
state.
Applications may attempt to create a new VkSurfaceKHR using the same
native platform window object, but whether such re-creation will succeed is
platform-dependent and may depend on the reason the surface became
unavailable.
A lost surface does not otherwise cause devices to be
lost.
To destroy a VkSurfaceKHR object, call:
void vkDestroySurfaceKHR(
VkInstance instance,
VkSurfaceKHR surface,
const VkAllocationCallbacks* pAllocator);
-
instanceis the instance used to create the surface. -
surfaceis the surface to destroy. -
pAllocatoris the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation).
Destroying a VkSurfaceKHR merely severs the connection between Vulkan
and the native surface, and does not imply destroying the native surface,
closing a window, or similar behavior.
30.3. Presenting Directly to Display Devices
In some environments applications can also present Vulkan rendering
directly to display devices without using an intermediate windowing system.
This can be useful for embedded applications, or implementing the
rendering/presentation backend of a windowing system using Vulkan.
The VK_KHR_display extension provides the functionality necessary to
enumerate display devices and create VkSurfaceKHR objects that target
displays.
30.3.1. Display Enumeration
Displays are represented by VkDisplayKHR handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDisplayKHR)
Various functions are provided for enumerating the available display devices present on a Vulkan physical device. To query information about the available displays, call:
VkResult vkGetPhysicalDeviceDisplayPropertiesKHR(
VkPhysicalDevice physicalDevice,
uint32_t* pPropertyCount,
VkDisplayPropertiesKHR* pProperties);
-
physicalDeviceis a physical device. -
pPropertyCountis a pointer to an integer related to the number of display devices available or queried, as described below. -
pPropertiesis eitherNULLor a pointer to an array ofVkDisplayPropertiesKHRstructures.
If pProperties is NULL, then the number of display devices available
for physicalDevice is returned in pPropertyCount.
Otherwise, pPropertyCount must point to a variable set by the user to
the number of elements in the pProperties array, and on return the
variable is overwritten with the number of structures actually written to
pProperties.
If the value of pPropertyCount is less than the number of display
devices for physicalDevice, at most pPropertyCount structures
will be written.
If pPropertyCount is smaller than the number of display devices
available for physicalDevice, VK_INCOMPLETE will be returned
instead of VK_SUCCESS to indicate that not all the available values
were returned.
The VkDisplayPropertiesKHR structure is defined as:
typedef struct VkDisplayPropertiesKHR {
VkDisplayKHR display;
const char* displayName;
VkExtent2D physicalDimensions;
VkExtent2D physicalResolution;
VkSurfaceTransformFlagsKHR supportedTransforms;
VkBool32 planeReorderPossible;
VkBool32 persistentContent;
} VkDisplayPropertiesKHR;
-
displayis a handle that is used to refer to the display described here. This handle will be valid for the lifetime of the Vulkan instance. -
displayNameis a pointer to a NULL-terminated string containing the name of the display. Generally, this will be the name provided by the display’s EDID. It can beNULLif no suitable name is available. If notNULL, the memory it points to must remain accessible as long asdisplayis valid. -
physicalDimensionsdescribes the physical width and height of the visible portion of the display, in millimeters. -
physicalResolutiondescribes the physical, native, or preferred resolution of the display.
|
Note
For devices which have no natural value to return here, implementations should return the maximum resolution supported. |
-
supportedTransformstells which transforms are supported by this display. This will contain one or more of the bits fromVkSurfaceTransformFlagsKHR. -
planeReorderPossibletells whether the planes on this display can have their z order changed. If this isVK_TRUE, the application can re-arrange the planes on this display in any order relative to each other. -
persistentContenttells whether the display supports self-refresh/internal buffering. If this is true, the application can submit persistent present operations on swapchains created against this display.
|
Note
Persistent presents may have higher latency, and may use less power when the screen content is updated infrequently, or when only a portion of the screen needs to be updated in most frames. |
To query information about the available displays, call:
VkResult vkGetPhysicalDeviceDisplayProperties2KHR(
VkPhysicalDevice physicalDevice,
uint32_t* pPropertyCount,
VkDisplayProperties2KHR* pProperties);
-
physicalDeviceis a physical device. -
pPropertyCountis a pointer to an integer related to the number of display devices available or queried, as described below. -
pPropertiesis eitherNULLor a pointer to an array ofVkDisplayProperties2KHRstructures.
vkGetPhysicalDeviceDisplayProperties2KHR behaves similarly to
vkGetPhysicalDeviceDisplayPropertiesKHR, with the ability to return
extended information via chained output structures.
The VkDisplayProperties2KHR structure is defined as:
typedef struct VkDisplayProperties2KHR {
VkStructureType sType;
void* pNext;
VkDisplayPropertiesKHR displayProperties;
} VkDisplayProperties2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
displayPropertiesis an instance of the VkDisplayPropertiesKHR structure.
Acquiring and Releasing Displays
On some platforms, access to displays is limited to a single process or native driver instance. On such platforms, some or all of the displays may not be available to Vulkan if they are already in use by a native windowing system or other application.
To acquire permission to directly access a display in Vulkan from an X11 server, call:
VkResult vkAcquireXlibDisplayEXT(
VkPhysicalDevice physicalDevice,
Display* dpy,
VkDisplayKHR display);
-
physicalDeviceThe physical device the display is on. -
dpyA connection to the X11 server that currently ownsdisplay. -
displayThe display the caller wishes to control in Vulkan.
All permissions necessary to control the display are granted to the Vulkan
instance associated with physicalDevice until the display is released
or the X11 connection specified by dpy is terminated.
Permission to access the display may be temporarily revoked during periods
when the X11 server from which control was acquired itself looses access to
display.
During such periods, operations which require access to the display must
fail with an approriate error code.
If the X11 server associated with dpy does not own display, or
if permission to access it has already been acquired by another entity, the
call must return the error code VK_ERROR_INITIALIZATION_FAILED.
|
Note
One example of when an X11 server loses access to a display is when it loses ownership of its virtual terminal. |
When acquiring displays from an X11 server, an application may also wish to
enumerate and identify them using a native handle rather than a
VkDisplayKHR handle.
To determine the VkDisplayKHR handle corresponding to an X11 RandR
Output, call:
VkResult vkGetRandROutputDisplayEXT(
VkPhysicalDevice physicalDevice,
Display* dpy,
RROutput rrOutput,
VkDisplayKHR* pDisplay);
-
physicalDeviceThe physical device to query the display handle on. -
dpyA connection to the X11 server from whichrrOutputwas queried. -
rrOutputAn X11 RandR output ID. -
pDisplayThe corresponding VkDisplayKHR handle will be returned here.
If there is no VkDisplayKHR corresponding to rrOutput on
physicalDevice, VK_NULL_HANDLE must be returned in
pDisplay.
To release a previously acquired display, call:
VkResult vkReleaseDisplayEXT(
VkPhysicalDevice physicalDevice,
VkDisplayKHR display);
-
physicalDeviceThe physical device the display is on. -
displayThe display to release control of.
Display Planes
Images are presented to individual planes on a display. Devices must support at least one plane on each display. Planes can be stacked and blended to composite multiple images on one display. Devices may support only a fixed stacking order and fixed mapping between planes and displays, or they may allow arbitrary application specified stacking orders and mappings between planes and displays. To query the properties of device display planes, call:
VkResult vkGetPhysicalDeviceDisplayPlanePropertiesKHR(
VkPhysicalDevice physicalDevice,
uint32_t* pPropertyCount,
VkDisplayPlanePropertiesKHR* pProperties);
-
physicalDeviceis a physical device. -
pPropertyCountis a pointer to an integer related to the number of display planes available or queried, as described below. -
pPropertiesis eitherNULLor a pointer to an array ofVkDisplayPlanePropertiesKHRstructures.
If pProperties is NULL, then the number of display planes available
for physicalDevice is returned in pPropertyCount.
Otherwise, pPropertyCount must point to a variable set by the user to
the number of elements in the pProperties array, and on return the
variable is overwritten with the number of structures actually written to
pProperties.
If the value of pPropertyCount is less than the number of display
planes for physicalDevice, at most pPropertyCount structures
will be written.
The VkDisplayPlanePropertiesKHR structure is defined as:
typedef struct VkDisplayPlanePropertiesKHR {
VkDisplayKHR currentDisplay;
uint32_t currentStackIndex;
} VkDisplayPlanePropertiesKHR;
-
currentDisplayis the handle of the display the plane is currently associated with. If the plane is not currently attached to any displays, this will beVK_NULL_HANDLE. -
currentStackIndexis the current z-order of the plane. This will be between 0 and the value returned byvkGetPhysicalDeviceDisplayPlanePropertiesKHRinpPropertyCount.
To query the properties of a device’s display planes, call:
VkResult vkGetPhysicalDeviceDisplayPlaneProperties2KHR(
VkPhysicalDevice physicalDevice,
uint32_t* pPropertyCount,
VkDisplayPlaneProperties2KHR* pProperties);
-
physicalDeviceis a physical device. -
pPropertyCountis a pointer to an integer related to the number of display planes available or queried, as described below. -
pPropertiesis eitherNULLor a pointer to an array ofVkDisplayPlaneProperties2KHRstructures.
vkGetPhysicalDeviceDisplayPlaneProperties2KHR behaves similarly to
vkGetPhysicalDeviceDisplayPlanePropertiesKHR, with the ability to
return extended information via chained output structures.
The VkDisplayPlaneProperties2KHR structure is defined as:
typedef struct VkDisplayPlaneProperties2KHR {
VkStructureType sType;
void* pNext;
VkDisplayPlanePropertiesKHR displayPlaneProperties;
} VkDisplayPlaneProperties2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
displayPlanePropertiesis an instance of the VkDisplayPlanePropertiesKHR structure.
To determine which displays a plane is usable with, call
VkResult vkGetDisplayPlaneSupportedDisplaysKHR(
VkPhysicalDevice physicalDevice,
uint32_t planeIndex,
uint32_t* pDisplayCount,
VkDisplayKHR* pDisplays);
-
physicalDeviceis a physical device. -
planeIndexis the plane which the application wishes to use, and must be in the range [0, physical device plane count - 1]. -
pDisplayCountis a pointer to an integer related to the number of displays available or queried, as described below. -
pDisplaysis eitherNULLor a pointer to an array ofVkDisplayKHRhandles.
If pDisplays is NULL, then the number of displays usable with the
specified planeIndex for physicalDevice is returned in
pDisplayCount.
Otherwise, pDisplayCount must point to a variable set by the user to
the number of elements in the pDisplays array, and on return the
variable is overwritten with the number of handles actually written to
pDisplays.
If the value of pDisplayCount is less than the number of display
planes for physicalDevice, at most pDisplayCount handles will be
written.
If pDisplayCount is smaller than the number of displays usable with
the specified planeIndex for physicalDevice, VK_INCOMPLETE
will be returned instead of VK_SUCCESS to indicate that not all the
available values were returned.
Additional properties of displays are queried using specialized query functions.
Display Modes
Display modes are represented by VkDisplayModeKHR handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDisplayModeKHR)
Each display has one or more supported modes associated with it by default. These built-in modes are queried by calling:
VkResult vkGetDisplayModePropertiesKHR(
VkPhysicalDevice physicalDevice,
VkDisplayKHR display,
uint32_t* pPropertyCount,
VkDisplayModePropertiesKHR* pProperties);
-
physicalDeviceis the physical device associated withdisplay. -
displayis the display to query. -
pPropertyCountis a pointer to an integer related to the number of display modes available or queried, as described below. -
pPropertiesis eitherNULLor a pointer to an array ofVkDisplayModePropertiesKHRstructures.
If pProperties is NULL, then the number of display modes available
on the specified display for physicalDevice is returned in
pPropertyCount.
Otherwise, pPropertyCount must point to a variable set by the user to
the number of elements in the pProperties array, and on return the
variable is overwritten with the number of structures actually written to
pProperties.
If the value of pPropertyCount is less than the number of display
modes for physicalDevice, at most pPropertyCount structures will
be written.
If pPropertyCount is smaller than the number of display modes
available on the specified display for physicalDevice,
VK_INCOMPLETE will be returned instead of VK_SUCCESS to indicate
that not all the available values were returned.
The VkDisplayModePropertiesKHR structure is defined as:
typedef struct VkDisplayModePropertiesKHR {
VkDisplayModeKHR displayMode;
VkDisplayModeParametersKHR parameters;
} VkDisplayModePropertiesKHR;
-
displayModeis a handle to the display mode described in this structure. This handle will be valid for the lifetime of the Vulkan instance. -
parametersis aVkDisplayModeParametersKHRstructure describing the display parameters associated withdisplayMode.
To query the properties of a device’s built-in display modes, call:
VkResult vkGetDisplayModeProperties2KHR(
VkPhysicalDevice physicalDevice,
VkDisplayKHR display,
uint32_t* pPropertyCount,
VkDisplayModeProperties2KHR* pProperties);
-
physicalDeviceis the physical device associated withdisplay. -
displayis the display to query. -
pPropertyCountis a pointer to an integer related to the number of display modes available or queried, as described below. -
pPropertiesis eitherNULLor a pointer to an array ofVkDisplayModeProperties2KHRstructures.
vkGetDisplayModeProperties2KHR behaves similarly to
vkGetDisplayModePropertiesKHR, with the ability to return extended
information via chained output structures.
The VkDisplayModeProperties2KHR structure is defined as:
typedef struct VkDisplayModeProperties2KHR {
VkStructureType sType;
void* pNext;
VkDisplayModePropertiesKHR displayModeProperties;
} VkDisplayModeProperties2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
displayModePropertiesis an instance of the VkDisplayModePropertiesKHR structure.
The VkDisplayModeParametersKHR structure is defined as:
typedef struct VkDisplayModeParametersKHR {
VkExtent2D visibleRegion;
uint32_t refreshRate;
} VkDisplayModeParametersKHR;
-
visibleRegionis the 2D extents of the visible region. -
refreshRateis auint32_tthat is the number of times the display is refreshed each second multiplied by 1000.
|
Note
For example, a 60Hz display mode would report a |
Additional modes may also be created by calling:
VkResult vkCreateDisplayModeKHR(
VkPhysicalDevice physicalDevice,
VkDisplayKHR display,
const VkDisplayModeCreateInfoKHR* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkDisplayModeKHR* pMode);
-
physicalDeviceis the physical device associated withdisplay. -
displayis the display to create an additional mode for. -
pCreateInfois a VkDisplayModeCreateInfoKHR structure describing the new mode to create. -
pAllocatoris the allocator used for host memory allocated for the display mode object when there is no more specific allocator available (see Memory Allocation). -
pModereturns the handle of the mode created.
The VkDisplayModeCreateInfoKHR structure is defined as:
typedef struct VkDisplayModeCreateInfoKHR {
VkStructureType sType;
const void* pNext;
VkDisplayModeCreateFlagsKHR flags;
VkDisplayModeParametersKHR parameters;
} VkDisplayModeCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use, and must be zero. -
parametersis aVkDisplayModeParametersKHRstructure describing the display parameters to use in creating the new mode. If the parameters are not compatible with the specified display, the implementation must returnVK_ERROR_INITIALIZATION_FAILED.
Applications that wish to present directly to a display must select which layer, or “plane” of the display they wish to target, and a mode to use with the display. Each display supports at least one plane. The capabilities of a given mode and plane combination are determined by calling:
VkResult vkGetDisplayPlaneCapabilitiesKHR(
VkPhysicalDevice physicalDevice,
VkDisplayModeKHR mode,
uint32_t planeIndex,
VkDisplayPlaneCapabilitiesKHR* pCapabilities);
-
physicalDeviceis the physical device associated withdisplay -
modeis the display mode the application intends to program when using the specified plane. Note this parameter also implicitly specifies a display. -
planeIndexis the plane which the application intends to use with the display, and is less than the number of display planes supported by the device. -
pCapabilitiesis a pointer to a VkDisplayPlaneCapabilitiesKHR structure in which the capabilities are returned.
The VkDisplayPlaneCapabilitiesKHR structure is defined as:
typedef struct VkDisplayPlaneCapabilitiesKHR {
VkDisplayPlaneAlphaFlagsKHR supportedAlpha;
VkOffset2D minSrcPosition;
VkOffset2D maxSrcPosition;
VkExtent2D minSrcExtent;
VkExtent2D maxSrcExtent;
VkOffset2D minDstPosition;
VkOffset2D maxDstPosition;
VkExtent2D minDstExtent;
VkExtent2D maxDstExtent;
} VkDisplayPlaneCapabilitiesKHR;
-
supportedAlphais a bitmask of VkDisplayPlaneAlphaFlagBitsKHR describing the supported alpha blending modes. -
minSrcPositionis the minimum source rectangle offset supported by this plane using the specified mode. -
maxSrcPositionis the maximum source rectangle offset supported by this plane using the specified mode. Thexandycomponents ofmaxSrcPositionmust each be greater than or equal to thexandycomponents ofminSrcPosition, respectively. -
minSrcExtentis the minimum source rectangle size supported by this plane using the specified mode. -
maxSrcExtentis the maximum source rectangle size supported by this plane using the specified mode. -
minDstPosition,maxDstPosition,minDstExtent,maxDstExtentall have similar semantics to their corresponding*Src*equivalents, but apply to the output region within the mode rather than the input region within the source image. Unlike the*Src*offsets,minDstPositionandmaxDstPositionmay contain negative values.
The minimum and maximum position and extent fields describe the
implementation limits, if any, as they apply to the specified display mode
and plane.
Vendors may support displaying a subset of a swapchain’s presentable images
on the specified display plane.
This is expressed by returning minSrcPosition, maxSrcPosition,
minSrcExtent, and maxSrcExtent values that indicate a range of
possible positions and sizes may be used to specify the region within the
presentable images that source pixels will be read from when creating a
swapchain on the specified display mode and plane.
Vendors may also support mapping the presentable images’ content to a
subset or superset of the visible region in the specified display mode.
This is expressed by returning minDstPosition, maxDstPosition,
minDstExtent and maxDstExtent values that indicate a range of
possible positions and sizes may be used to describe the region within the
display mode that the source pixels will be mapped to.
Other vendors may support only a 1-1 mapping between pixels in the
presentable images and the display mode.
This may be indicated by returning (0,0) for minSrcPosition,
maxSrcPosition, minDstPosition, and maxDstPosition, and
(display mode width, display mode height) for minSrcExtent,
maxSrcExtent, minDstExtent, and maxDstExtent.
These values indicate the limits of the implementation’s individual fields.
Not all combinations of values within the offset and extent ranges returned
in VkDisplayPlaneCapabilitiesKHR are guaranteed to be supported.
Vendors may still fail presentation requests that specify unsupported
combinations.
To query the capabilities of a given mode and plane combination, call:
VkResult vkGetDisplayPlaneCapabilities2KHR(
VkPhysicalDevice physicalDevice,
const VkDisplayPlaneInfo2KHR* pDisplayPlaneInfo,
VkDisplayPlaneCapabilities2KHR* pCapabilities);
-
physicalDeviceis the physical device associated withpDisplayPlaneInfo. -
pDisplayPlaneInfois a pointer to an instance of the VkDisplayPlaneInfo2KHR structure describing the plane and mode. -
pCapabilitiesis a pointer to a VkDisplayPlaneCapabilities2KHR structure in which the capabilities are returned.
vkGetDisplayPlaneCapabilities2KHR behaves similarly to
vkGetDisplayPlaneCapabilitiesKHR, with the ability to specify extended
inputs via chained input structures, and to return extended information via
chained output structures.
The VkDisplayPlaneInfo2KHR structure is defined as:
typedef struct VkDisplayPlaneInfo2KHR {
VkStructureType sType;
const void* pNext;
VkDisplayModeKHR mode;
uint32_t planeIndex;
} VkDisplayPlaneInfo2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
modeis the display mode the application intends to program when using the specified plane.
|
Note
This parameter also implicitly specifies a display. |
-
planeIndexis the plane which the application intends to use with the display.
The members of VkDisplayPlaneInfo2KHR correspond to the arguments to
vkGetDisplayPlaneCapabilitiesKHR, with sType and pNext
added for extensibility.
The VkDisplayPlaneCapabilities2KHR structure is defined as:
typedef struct VkDisplayPlaneCapabilities2KHR {
VkStructureType sType;
void* pNext;
VkDisplayPlaneCapabilitiesKHR capabilities;
} VkDisplayPlaneCapabilities2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
capabilitiesis an instance of the VkDisplayPlaneCapabilitiesKHR structure.
30.3.2. Display Control
To set the power state of a display, call:
VkResult vkDisplayPowerControlEXT(
VkDevice device,
VkDisplayKHR display,
const VkDisplayPowerInfoEXT* pDisplayPowerInfo);
-
deviceis a logical device associated withdisplay. -
displayis the display whose power state is modified. -
pDisplayPowerInfois an instance of VkDisplayPowerInfoEXT specifying the new power state ofdisplay.
The VkDisplayPowerInfoEXT structure is defined as:
typedef struct VkDisplayPowerInfoEXT {
VkStructureType sType;
const void* pNext;
VkDisplayPowerStateEXT powerState;
} VkDisplayPowerInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
powerStateis a VkDisplayPowerStateEXT value specifying the new power state of the display.
Possible values of VkDisplayPowerInfoEXT::powerState, specifying
the new power state of a display, are:
typedef enum VkDisplayPowerStateEXT {
VK_DISPLAY_POWER_STATE_OFF_EXT = 0,
VK_DISPLAY_POWER_STATE_SUSPEND_EXT = 1,
VK_DISPLAY_POWER_STATE_ON_EXT = 2,
} VkDisplayPowerStateEXT;
-
VK_DISPLAY_POWER_STATE_OFF_EXTspecifies that the display is powered down. -
VK_DISPLAY_POWER_STATE_SUSPEND_EXTspecifies that the display is put into a low power mode, from which it may be able to transition back toVK_DISPLAY_POWER_STATE_ON_EXTmore quickly than if it were inVK_DISPLAY_POWER_STATE_OFF_EXT. This state may be the same asVK_DISPLAY_POWER_STATE_OFF_EXT. -
VK_DISPLAY_POWER_STATE_ON_EXTspecifies that the display is powered on.
30.3.3. Display Surfaces
A complete display configuration includes a mode, one or more display planes
and any parameters describing their behavior, and parameters describing some
aspects of the images associated with those planes.
Display surfaces describe the configuration of a single plane within a
complete display configuration.
To create a VkSurfaceKHR structure for a display surface, call:
VkResult vkCreateDisplayPlaneSurfaceKHR(
VkInstance instance,
const VkDisplaySurfaceCreateInfoKHR* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkSurfaceKHR* pSurface);
-
instanceis the instance corresponding to the physical device the targeted display is on. -
pCreateInfois a pointer to an instance of the VkDisplaySurfaceCreateInfoKHR structure specifying which mode, plane, and other parameters to use, as described below. -
pAllocatoris the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation). -
pSurfacepoints to aVkSurfaceKHRhandle in which the created surface is returned.
The VkDisplaySurfaceCreateInfoKHR structure is defined as:
typedef struct VkDisplaySurfaceCreateInfoKHR {
VkStructureType sType;
const void* pNext;
VkDisplaySurfaceCreateFlagsKHR flags;
VkDisplayModeKHR displayMode;
uint32_t planeIndex;
uint32_t planeStackIndex;
VkSurfaceTransformFlagBitsKHR transform;
float globalAlpha;
VkDisplayPlaneAlphaFlagBitsKHR alphaMode;
VkExtent2D imageExtent;
} VkDisplaySurfaceCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis reserved for future use, and must be zero. -
displayModeis a VkDisplayModeKHR handle specifying the mode to use when displaying this surface. -
planeIndexis the plane on which this surface appears. -
planeStackIndexis the z-order of the plane. -
transformis a VkSurfaceTransformFlagBitsKHR value specifying the transformation to apply to images as part of the scanout operation. -
globalAlphais the global alpha value. This value is ignored ifalphaModeis notVK_DISPLAY_PLANE_ALPHA_GLOBAL_BIT_KHR. -
alphaModeis a VkDisplayPlaneAlphaFlagBitsKHR value specifying the type of alpha blending to use. -
imageExtentThe size of the presentable images to use with the surface.
|
Note
Creating a display surface must not modify the state of the displays, planes, or other resources it names. For example, it must not apply the specified mode to be set on the associated display. Application of display configuration occurs as a side effect of presenting to a display surface. |
Possible values of VkDisplaySurfaceCreateInfoKHR::alphaMode,
specifying the type of alpha blending to use on a display, are:
typedef enum VkDisplayPlaneAlphaFlagBitsKHR {
VK_DISPLAY_PLANE_ALPHA_OPAQUE_BIT_KHR = 0x00000001,
VK_DISPLAY_PLANE_ALPHA_GLOBAL_BIT_KHR = 0x00000002,
VK_DISPLAY_PLANE_ALPHA_PER_PIXEL_BIT_KHR = 0x00000004,
VK_DISPLAY_PLANE_ALPHA_PER_PIXEL_PREMULTIPLIED_BIT_KHR = 0x00000008,
} VkDisplayPlaneAlphaFlagBitsKHR;
-
VK_DISPLAY_PLANE_ALPHA_OPAQUE_BIT_KHRspecifies that the source image will be treated as opaque. -
VK_DISPLAY_PLANE_ALPHA_GLOBAL_BIT_KHRspecifies that a global alpha value must be specified that will be applied to all pixels in the source image. -
VK_DISPLAY_PLANE_ALPHA_PER_PIXEL_BIT_KHRspecifies that the alpha value will be determined by the alpha channel of the source image’s pixels. If the source format contains no alpha values, no blending will be applied. The source alpha values are not premultiplied into the source image’s other color channels. -
VK_DISPLAY_PLANE_ALPHA_PER_PIXEL_PREMULTIPLIED_BIT_KHRis equivalent toVK_DISPLAY_PLANE_ALPHA_PER_PIXEL_BIT_KHR, except the source alpha values are assumed to be premultiplied into the source image’s other color channels.
typedef VkFlags VkDisplayPlaneAlphaFlagsKHR;
VkDisplayPlaneAlphaFlagsKHR is a bitmask type for setting a mask of
zero or more VkDisplayPlaneAlphaFlagBitsKHR.
30.4. Querying for WSI Support
Not all physical devices will include WSI support. Within a physical device, not all queue families will support presentation. WSI support and compatibility can be determined in a platform-neutral manner (which determines support for presentation to a particular surface object) and additionally may be determined in platform-specific manners (which determine support for presentation on the specified physical device but do not guarantee support for presentation to a particular surface object).
To determine whether a queue family of a physical device supports presentation to a given surface, call:
VkResult vkGetPhysicalDeviceSurfaceSupportKHR(
VkPhysicalDevice physicalDevice,
uint32_t queueFamilyIndex,
VkSurfaceKHR surface,
VkBool32* pSupported);
-
physicalDeviceis the physical device. -
queueFamilyIndexis the queue family. -
surfaceis the surface. -
pSupportedis a pointer to aVkBool32, which is set toVK_TRUEto indicate support, andVK_FALSEotherwise.
30.4.1. Android Platform
On Android, all physical devices and queue families must be capable of presentation with any native window. As a result there is no Android-specific query for these capabilities.
30.4.2. Mir Platform
To determine whether a queue family of a physical device supports presentation to the Mir compositor, call:
VkBool32 vkGetPhysicalDeviceMirPresentationSupportKHR(
VkPhysicalDevice physicalDevice,
uint32_t queueFamilyIndex,
MirConnection* connection);
-
physicalDeviceis the physical device. -
queueFamilyIndexis the queue family index. -
connectionis a pointer to theMirConnection, and identifies the desired Mir compositor.
This platform-specific function can be called prior to creating a surface.
30.4.3. Wayland Platform
To determine whether a queue family of a physical device supports presentation to a Wayland compositor, call:
VkBool32 vkGetPhysicalDeviceWaylandPresentationSupportKHR(
VkPhysicalDevice physicalDevice,
uint32_t queueFamilyIndex,
struct wl_display* display);
-
physicalDeviceis the physical device. -
queueFamilyIndexis the queue family index. -
displayis a pointer to thewl_displayassociated with a Wayland compositor.
This platform-specific function can be called prior to creating a surface.
30.4.4. Win32 Platform
To determine whether a queue family of a physical device supports presentation to the Microsoft Windows desktop, call:
VkBool32 vkGetPhysicalDeviceWin32PresentationSupportKHR(
VkPhysicalDevice physicalDevice,
uint32_t queueFamilyIndex);
-
physicalDeviceis the physical device. -
queueFamilyIndexis the queue family index.
This platform-specific function can be called prior to creating a surface.
30.4.5. XCB Platform
To determine whether a queue family of a physical device supports presentation to an X11 server, using the XCB client-side library, call:
VkBool32 vkGetPhysicalDeviceXcbPresentationSupportKHR(
VkPhysicalDevice physicalDevice,
uint32_t queueFamilyIndex,
xcb_connection_t* connection,
xcb_visualid_t visual_id);
-
physicalDeviceis the physical device. -
queueFamilyIndexis the queue family index. -
connectionis a pointer to anxcb_connection_tto the X server.visual_idis an X11 visual (xcb_visualid_t).
This platform-specific function can be called prior to creating a surface.
30.4.6. Xlib Platform
To determine whether a queue family of a physical device supports presentation to an X11 server, using the Xlib client-side library, call:
VkBool32 vkGetPhysicalDeviceXlibPresentationSupportKHR(
VkPhysicalDevice physicalDevice,
uint32_t queueFamilyIndex,
Display* dpy,
VisualID visualID);
-
physicalDeviceis the physical device. -
queueFamilyIndexis the queue family index. -
dpyis a pointer to an XlibDisplayconnection to the server. -
visualIdis an X11 visual (VisualID).
This platform-specific function can be called prior to creating a surface.
30.4.7. iOS Platform
On iOS, all physical devices and queue families must be capable of presentation with any layer. As a result there is no iOS-specific query for these capabilities.
30.4.8. macOS Platform
On macOS, all physical devices and queue families must be capable of presentation with any layer. As a result there is no macOS-specific query for these capabilities.
30.4.9. VI Platform
On VI, all physical devices and queue families must be capable of presentation with any layer. As a result there is no VI-specific query for these capabilities.
30.5. Surface Queries
The capabilities of a swapchain targetting a surface are the intersection of the capabilities of the WSI platform, the native window or display, and the physical device. The resulting capabilities can be obtained with the queries listed below in this section. Capabilities that correspond to image creation parameters are not independent of each other: combinations of parameters that are not supported as reported by vkGetPhysicalDeviceImageFormatProperties are not supported by the surface on that physical device, even if the capabilities taken individually are supported as part of some other parameter combinations.
To query the basic capabilities of a surface, needed in order to create a swapchain, call:
VkResult vkGetPhysicalDeviceSurfaceCapabilitiesKHR(
VkPhysicalDevice physicalDevice,
VkSurfaceKHR surface,
VkSurfaceCapabilitiesKHR* pSurfaceCapabilities);
-
physicalDeviceis the physical device that will be associated with the swapchain to be created, as described for vkCreateSwapchainKHR. -
surfaceis the surface that will be associated with the swapchain. -
pSurfaceCapabilitiesis a pointer to an instance of the VkSurfaceCapabilitiesKHR structure in which the capabilities are returned.
The VkSurfaceCapabilitiesKHR structure is defined as:
typedef struct VkSurfaceCapabilitiesKHR {
uint32_t minImageCount;
uint32_t maxImageCount;
VkExtent2D currentExtent;
VkExtent2D minImageExtent;
VkExtent2D maxImageExtent;
uint32_t maxImageArrayLayers;
VkSurfaceTransformFlagsKHR supportedTransforms;
VkSurfaceTransformFlagBitsKHR currentTransform;
VkCompositeAlphaFlagsKHR supportedCompositeAlpha;
VkImageUsageFlags supportedUsageFlags;
} VkSurfaceCapabilitiesKHR;
-
minImageCountis the minimum number of images the specified device supports for a swapchain created for the surface, and will be at least one. -
maxImageCountis the maximum number of images the specified device supports for a swapchain created for the surface, and will be either 0, or greater than or equal tominImageCount. A value of 0 means that there is no limit on the number of images, though there may be limits related to the total amount of memory used by presentable images. -
currentExtentis the current width and height of the surface, or the special value (0xFFFFFFFF, 0xFFFFFFFF) indicating that the surface size will be determined by the extent of a swapchain targeting the surface. -
minImageExtentcontains the smallest valid swapchain extent for the surface on the specified device. Thewidthandheightof the extent will each be less than or equal to the correspondingwidthandheightofcurrentExtent, unlesscurrentExtenthas the special value described above. -
maxImageExtentcontains the largest valid swapchain extent for the surface on the specified device. Thewidthandheightof the extent will each be greater than or equal to the correspondingwidthandheightofminImageExtent. Thewidthandheightof the extent will each be greater than or equal to the correspondingwidthandheightofcurrentExtent, unlesscurrentExtenthas the special value described above. -
maxImageArrayLayersis the maximum number of layers presentable images can have for a swapchain created for this device and surface, and will be at least one. -
supportedTransformsis a bitmask of VkSurfaceTransformFlagBitsKHR indicating the presentation transforms supported for the surface on the specified device. At least one bit will be set. -
currentTransformis VkSurfaceTransformFlagBitsKHR value indicating the surface’s current transform relative to the presentation engine’s natural orientation. -
supportedCompositeAlphais a bitmask of VkCompositeAlphaFlagBitsKHR, representing the alpha compositing modes supported by the presentation engine for the surface on the specified device, and at least one bit will be set. Opaque composition can be achieved in any alpha compositing mode by either using an image format that has no alpha component, or by ensuring that all pixels in the presentable images have an alpha value of 1.0. -
supportedUsageFlagsis a bitmask of VkImageUsageFlagBits representing the ways the application can use the presentable images of a swapchain created with VkPresentModeKHR set toVK_PRESENT_MODE_IMMEDIATE_KHR,VK_PRESENT_MODE_MAILBOX_KHR,VK_PRESENT_MODE_FIFO_KHRorVK_PRESENT_MODE_FIFO_RELAXED_KHRfor the surface on the specified device.VK_IMAGE_USAGE_COLOR_ATTACHMENT_BITmust be included in the set but implementations may support additional usages.
|
Note
Supported usage flags of a presentable image when using
|
|
Note
Formulas such as min(N, |
To query the basic capabilities of a surface defined by the core or extensions, call:
VkResult vkGetPhysicalDeviceSurfaceCapabilities2KHR(
VkPhysicalDevice physicalDevice,
const VkPhysicalDeviceSurfaceInfo2KHR* pSurfaceInfo,
VkSurfaceCapabilities2KHR* pSurfaceCapabilities);
-
physicalDeviceis the physical device that will be associated with the swapchain to be created, as described for vkCreateSwapchainKHR. -
pSurfaceInfopoints to an instance of the VkPhysicalDeviceSurfaceInfo2KHR structure, describing the surface and other fixed parameters that would be consumed by vkCreateSwapchainKHR. -
pSurfaceCapabilitiespoints to an instance of the VkSurfaceCapabilities2KHR structure in which the capabilities are returned.
vkGetPhysicalDeviceSurfaceCapabilities2KHR behaves similarly to
vkGetPhysicalDeviceSurfaceCapabilitiesKHR, with the ability to specify
extended inputs via chained input structures, and to return extended
information via chained output structures.
The VkPhysicalDeviceSurfaceInfo2KHR structure is defined as:
typedef struct VkPhysicalDeviceSurfaceInfo2KHR {
VkStructureType sType;
const void* pNext;
VkSurfaceKHR surface;
} VkPhysicalDeviceSurfaceInfo2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
surfaceis the surface that will be associated with the swapchain.
The members of VkPhysicalDeviceSurfaceInfo2KHR correspond to the
arguments to vkGetPhysicalDeviceSurfaceCapabilitiesKHR, with
sType and pNext added for extensibility.
The VkSurfaceCapabilities2KHR structure is defined as:
typedef struct VkSurfaceCapabilities2KHR {
VkStructureType sType;
void* pNext;
VkSurfaceCapabilitiesKHR surfaceCapabilities;
} VkSurfaceCapabilities2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
surfaceCapabilitiesis a structure of type VkSurfaceCapabilitiesKHR describing the capabilities of the specified surface.
The VkSharedPresentSurfaceCapabilitiesKHR structure is defined as:
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
sharedPresentSupportedUsageFlagsis a bitmask of VkImageUsageFlagBits representing the ways the application can use the shared presentable image from a swapchain created with VkPresentModeKHR set toVK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHRorVK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHRfor the surface on the specified device.VK_IMAGE_USAGE_COLOR_ATTACHMENT_BITmust be included in the set but implementations may support additional usages.
To query the basic capabilities of a surface, needed in order to create a swapchain, call:
VkResult vkGetPhysicalDeviceSurfaceCapabilities2EXT(
VkPhysicalDevice physicalDevice,
VkSurfaceKHR surface,
VkSurfaceCapabilities2EXT* pSurfaceCapabilities);
-
physicalDeviceis the physical device that will be associated with the swapchain to be created, as described for vkCreateSwapchainKHR. -
surfaceis the surface that will be associated with the swapchain. -
pSurfaceCapabilitiesis a pointer to an instance of the VkSurfaceCapabilities2EXT structure in which the capabilities are returned.
vkGetPhysicalDeviceSurfaceCapabilities2EXT behaves similarly to
vkGetPhysicalDeviceSurfaceCapabilitiesKHR, with the ability to return
extended information by adding extension structures to the pNext chain
of its pSurfaceCapabilities parameter.
The VkSurfaceCapabilities2EXT structure is defined as:
typedef struct VkSurfaceCapabilities2EXT {
VkStructureType sType;
void* pNext;
uint32_t minImageCount;
uint32_t maxImageCount;
VkExtent2D currentExtent;
VkExtent2D minImageExtent;
VkExtent2D maxImageExtent;
uint32_t maxImageArrayLayers;
VkSurfaceTransformFlagsKHR supportedTransforms;
VkSurfaceTransformFlagBitsKHR currentTransform;
VkCompositeAlphaFlagsKHR supportedCompositeAlpha;
VkImageUsageFlags supportedUsageFlags;
VkSurfaceCounterFlagsEXT supportedSurfaceCounters;
} VkSurfaceCapabilities2EXT;
All members of VkSurfaceCapabilities2EXT are identical to the
corresponding members of VkSurfaceCapabilitiesKHR where one exists.
The remaining members are:
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
supportedSurfaceCountersis a bitmask of VkSurfaceCounterFlagBitsEXT indicating the supported surface counter types.
Bits which can be set in
VkSurfaceCapabilities2EXT::supportedSurfaceCounters, indicating
supported surface counter types, are:
typedef enum VkSurfaceCounterFlagBitsEXT {
VK_SURFACE_COUNTER_VBLANK_EXT = 0x00000001,
} VkSurfaceCounterFlagBitsEXT;
-
VK_SURFACE_COUNTER_VBLANK_EXTspecifies a counter incrementing once every time a vertical blanking period occurs on the display associated with the surface.
typedef VkFlags VkSurfaceCounterFlagsEXT;
VkSurfaceCounterFlagsEXT is a bitmask type for setting a mask of zero
or more VkSurfaceCounterFlagBitsEXT.
Bits which may be set in
VkSurfaceCapabilitiesKHR::supportedTransforms indicating the
presentation transforms supported for the surface on the specified device,
and possible values of
VkSurfaceCapabilitiesKHR::currentTransform is indicating the
surface’s current transform relative to the presentation engine’s natural
orientation, are:
typedef enum VkSurfaceTransformFlagBitsKHR {
VK_SURFACE_TRANSFORM_IDENTITY_BIT_KHR = 0x00000001,
VK_SURFACE_TRANSFORM_ROTATE_90_BIT_KHR = 0x00000002,
VK_SURFACE_TRANSFORM_ROTATE_180_BIT_KHR = 0x00000004,
VK_SURFACE_TRANSFORM_ROTATE_270_BIT_KHR = 0x00000008,
VK_SURFACE_TRANSFORM_HORIZONTAL_MIRROR_BIT_KHR = 0x00000010,
VK_SURFACE_TRANSFORM_HORIZONTAL_MIRROR_ROTATE_90_BIT_KHR = 0x00000020,
VK_SURFACE_TRANSFORM_HORIZONTAL_MIRROR_ROTATE_180_BIT_KHR = 0x00000040,
VK_SURFACE_TRANSFORM_HORIZONTAL_MIRROR_ROTATE_270_BIT_KHR = 0x00000080,
VK_SURFACE_TRANSFORM_INHERIT_BIT_KHR = 0x00000100,
} VkSurfaceTransformFlagBitsKHR;
-
VK_SURFACE_TRANSFORM_IDENTITY_BIT_KHRspecifies that image content is presented without being transformed. -
VK_SURFACE_TRANSFORM_ROTATE_90_BIT_KHRspecifies that image content is rotated 90 degrees clockwise. -
VK_SURFACE_TRANSFORM_ROTATE_180_BIT_KHRspecifies that image content is rotated 180 degrees clockwise. -
VK_SURFACE_TRANSFORM_ROTATE_270_BIT_KHRspecifies that image content is rotated 270 degrees clockwise. -
VK_SURFACE_TRANSFORM_HORIZONTAL_MIRROR_BIT_KHRspecifies that image content is mirrored horizontally. -
VK_SURFACE_TRANSFORM_HORIZONTAL_MIRROR_ROTATE_90_BIT_KHRspecifies that image content is mirrored horizontally, then rotated 90 degrees clockwise. -
VK_SURFACE_TRANSFORM_HORIZONTAL_MIRROR_ROTATE_180_BIT_KHRspecifies that image content is mirrored horizontally, then rotated 180 degrees clockwise. -
VK_SURFACE_TRANSFORM_HORIZONTAL_MIRROR_ROTATE_270_BIT_KHRspecifies that image content is mirrored horizontally, then rotated 270 degrees clockwise. -
VK_SURFACE_TRANSFORM_INHERIT_BIT_KHRspecifies that the presentation transform is not specified, and is instead determined by platform-specific considerations and mechanisms outside Vulkan.
typedef VkFlags VkSurfaceTransformFlagsKHR;
VkSurfaceTransformFlagsKHR is a bitmask type for setting a mask of
zero or more VkSurfaceTransformFlagBitsKHR.
The supportedCompositeAlpha member is of type
VkCompositeAlphaFlagBitsKHR, which contains the following values:
typedef enum VkCompositeAlphaFlagBitsKHR {
VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR = 0x00000001,
VK_COMPOSITE_ALPHA_PRE_MULTIPLIED_BIT_KHR = 0x00000002,
VK_COMPOSITE_ALPHA_POST_MULTIPLIED_BIT_KHR = 0x00000004,
VK_COMPOSITE_ALPHA_INHERIT_BIT_KHR = 0x00000008,
} VkCompositeAlphaFlagBitsKHR;
These values are described as follows:
-
VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR: The alpha channel, if it exists, of the images is ignored in the compositing process. Instead, the image is treated as if it has a constant alpha of 1.0. -
VK_COMPOSITE_ALPHA_PRE_MULTIPLIED_BIT_KHR: The alpha channel, if it exists, of the images is respected in the compositing process. The non-alpha channels of the image are expected to already be multiplied by the alpha channel by the application. -
VK_COMPOSITE_ALPHA_POST_MULTIPLIED_BIT_KHR: The alpha channel, if it exists, of the images is respected in the compositing process. The non-alpha channels of the image are not expected to already be multiplied by the alpha channel by the application; instead, the compositor will multiply the non-alpha channels of the image by the alpha channel during compositing. -
VK_COMPOSITE_ALPHA_INHERIT_BIT_KHR: The way in which the presentation engine treats the alpha channel in the images is unknown to the Vulkan API. Instead, the application is responsible for setting the composite alpha blending mode using native window system commands. If the application does not set the blending mode using native window system commands, then a platform-specific default will be used.
typedef VkFlags VkCompositeAlphaFlagsKHR;
VkCompositeAlphaFlagsKHR is a bitmask type for setting a mask of zero
or more VkCompositeAlphaFlagBitsKHR.
To query the supported swapchain format-color space pairs for a surface, call:
VkResult vkGetPhysicalDeviceSurfaceFormatsKHR(
VkPhysicalDevice physicalDevice,
VkSurfaceKHR surface,
uint32_t* pSurfaceFormatCount,
VkSurfaceFormatKHR* pSurfaceFormats);
-
physicalDeviceis the physical device that will be associated with the swapchain to be created, as described for vkCreateSwapchainKHR. -
surfaceis the surface that will be associated with the swapchain. -
pSurfaceFormatCountis a pointer to an integer related to the number of format pairs available or queried, as described below. -
pSurfaceFormatsis eitherNULLor a pointer to an array ofVkSurfaceFormatKHRstructures.
If pSurfaceFormats is NULL, then the number of format pairs
supported for the given surface is returned in
pSurfaceFormatCount.
The number of format pairs supported will be greater than or equal to 1.
Otherwise, pSurfaceFormatCount must point to a variable set by the
user to the number of elements in the pSurfaceFormats array, and on
return the variable is overwritten with the number of structures actually
written to pSurfaceFormats.
If the value of pSurfaceFormatCount is less than the number of format
pairs supported, at most pSurfaceFormatCount structures will be
written.
If pSurfaceFormatCount is smaller than the number of format pairs
supported for the given surface, VK_INCOMPLETE will be returned
instead of VK_SUCCESS to indicate that not all the available values
were returned.
The VkSurfaceFormatKHR structure is defined as:
typedef struct VkSurfaceFormatKHR {
VkFormat format;
VkColorSpaceKHR colorSpace;
} VkSurfaceFormatKHR;
-
formatis a VkFormat that is compatible with the specified surface. -
colorSpaceis a presentation VkColorSpaceKHR that is compatible with the surface.
To query the supported swapchain format tuples for a surface, call:
VkResult vkGetPhysicalDeviceSurfaceFormats2KHR(
VkPhysicalDevice physicalDevice,
const VkPhysicalDeviceSurfaceInfo2KHR* pSurfaceInfo,
uint32_t* pSurfaceFormatCount,
VkSurfaceFormat2KHR* pSurfaceFormats);
-
physicalDeviceis the physical device that will be associated with the swapchain to be created, as described for vkCreateSwapchainKHR. -
pSurfaceInfopoints to an instance of the VkPhysicalDeviceSurfaceInfo2KHR structure, describing the surface and other fixed parameters that would be consumed by vkCreateSwapchainKHR. -
pSurfaceFormatCountis a pointer to an integer related to the number of format tuples available or queried, as described below. -
pSurfaceFormatsis eitherNULLor a pointer to an array of VkSurfaceFormat2KHR structures.
If pSurfaceFormats is NULL, then the number of format tuples
supported for the given surface is returned in
pSurfaceFormatCount.
The number of format tuples supported will be greater than or equal to 1.
Otherwise, pSurfaceFormatCount must point to a variable set by the
user to the number of elements in the pSurfaceFormats array, and on
return the variable is overwritten with the number of structures actually
written to pSurfaceFormats.
If the value of pSurfaceFormatCount is less than the number of format
tuples supported, at most pSurfaceFormatCount structures will be
written.
If pSurfaceFormatCount is smaller than the number of format tuples
supported for the surface parameters described in pSurfaceInfo,
VK_INCOMPLETE will be returned instead of VK_SUCCESS to indicate
that not all the available values were returned.
The VkSurfaceFormat2KHR structure is defined as:
typedef struct VkSurfaceFormat2KHR {
VkStructureType sType;
void* pNext;
VkSurfaceFormatKHR surfaceFormat;
} VkSurfaceFormat2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
surfaceFormatis an instance of VkSurfaceFormatKHR describing a format-color space pair that is compatible with the specified surface.
While the format of a presentable image refers to the encoding of each
pixel, the colorSpace determines how the presentation engine
interprets the pixel values.
A color space in this document refers to a specific color space (defined by
the chromaticities of its primaries and a white point in CIE Lab), and a
transfer function that is applied before storing or transmitting color data
in the given color space.
Possible values of VkSurfaceFormatKHR::colorSpace, specifying
supported color spaces of a presentation engine, are:
typedef enum VkColorSpaceKHR {
VK_COLOR_SPACE_SRGB_NONLINEAR_KHR = 0,
VK_COLOR_SPACE_DISPLAY_P3_NONLINEAR_EXT = 1000104001,
VK_COLOR_SPACE_EXTENDED_SRGB_LINEAR_EXT = 1000104002,
VK_COLOR_SPACE_DCI_P3_LINEAR_EXT = 1000104003,
VK_COLOR_SPACE_DCI_P3_NONLINEAR_EXT = 1000104004,
VK_COLOR_SPACE_BT709_LINEAR_EXT = 1000104005,
VK_COLOR_SPACE_BT709_NONLINEAR_EXT = 1000104006,
VK_COLOR_SPACE_BT2020_LINEAR_EXT = 1000104007,
VK_COLOR_SPACE_HDR10_ST2084_EXT = 1000104008,
VK_COLOR_SPACE_DOLBYVISION_EXT = 1000104009,
VK_COLOR_SPACE_HDR10_HLG_EXT = 1000104010,
VK_COLOR_SPACE_ADOBERGB_LINEAR_EXT = 1000104011,
VK_COLOR_SPACE_ADOBERGB_NONLINEAR_EXT = 1000104012,
VK_COLOR_SPACE_PASS_THROUGH_EXT = 1000104013,
VK_COLOR_SPACE_EXTENDED_SRGB_NONLINEAR_EXT = 1000104014,
} VkColorSpaceKHR;
-
VK_COLOR_SPACE_SRGB_NONLINEAR_KHRspecifies support for the sRGB color space. -
VK_COLOR_SPACE_DISPLAY_P3_NONLINEAR_EXTspecifies support for the Display-P3 color space and applies an sRGB-like transfer function (defined below). -
VK_COLOR_SPACE_EXTENDED_SRGB_LINEAR_EXTspecifies support for the extended sRGB color space and applies a linear transfer function. -
VK_COLOR_SPACE_EXTENDED_SRGB_NONLINEAR_EXTspecifies support for the extended sRGB color space and applies an sRGB transfer function. -
VK_COLOR_SPACE_DCI_P3_LINEAR_EXTspecifies support for the DCI-P3 color space and applies a linear OETF. -
VK_COLOR_SPACE_DCI_P3_NONLINEAR_EXTspecifies support for the DCI-P3 color space and applies the Gamma 2.6 OETF. -
VK_COLOR_SPACE_BT709_LINEAR_EXTspecifies support for the BT709 color space and applies a linear OETF. -
VK_COLOR_SPACE_BT709_NONLINEAR_EXTspecifies support for the BT709 color space and applies the SMPTE 170M OETF. -
VK_COLOR_SPACE_BT2020_LINEAR_EXTspecifies support for the BT2020 color space and applies a linear OETF. -
VK_COLOR_SPACE_HDR10_ST2084_EXTspecifies support for the HDR10 (BT2020 color) space and applies the SMPTE ST2084 Perceptual Quantizer (PQ) OETF. -
VK_COLOR_SPACE_DOLBYVISION_EXTspecifies support for the Dolby Vision (BT2020 color space), proprietary encoding, and applies the SMPTE ST2084 OETF. -
VK_COLOR_SPACE_HDR10_HLG_EXTspecifies support for the HDR10 (BT2020 color space) and applies the Hybrid Log Gamma (HLG) OETF. -
VK_COLOR_SPACE_ADOBERGB_LINEAR_EXTspecifies support for the AdobeRGB color space and applies a linear OETF. -
VK_COLOR_SPACE_ADOBERGB_NONLINEAR_EXTspecifies support for the AdobeRGB color space and applies the Gamma 2.2 OETF. -
VK_COLOR_SPACE_PASS_THROUGH_EXTspecifies that color components are used “as is”. This is intended to allow applications to supply data for color spaces not described here.
The color components of Non-linear color space swap chain images have had the appropriate transfer function applied. Vulkan requires that all implementations support the sRGB transfer function when using an SRGB pixel format. Other transfer functions, such as SMPTE 170M or SMPTE2084, must not be performed by the implementation, but can be performed by the application shader. This extension defines enums for VkColorSpaceKHR that correspond to the following color spaces:
| Name | Red Primary | Green Primary | Blue Primary | White-point | Transfer function |
|---|---|---|---|---|---|
DCI-P3 |
0.680, 0.320 |
0.265, 0.690 |
0.150, 0.060 |
0.3127, 0.3290 (D65) |
Gamma 2.6 |
Display-P3 |
0.680, 0.320 |
0.265, 0.690 |
0.150, 0.060 |
0.3127, 0.3290 (D65) |
Display-P3 |
BT709 |
0.640, 0.330 |
0.300, 0.600 |
0.150, 0.060 |
0.3127, 0.3290 (D65) |
SMPTE 170M |
sRGB |
0.640, 0.330 |
0.300, 0.600 |
0.150, 0.060 |
0.3127, 0.3290 (D65) |
sRGB |
extended sRGB |
0.640, 0.330 |
0.300, 0.600 |
0.150, 0.060 |
0.3127, 0.3290 (D65) |
extended sRGB |
HDR10_ST2084 |
0.708, 0.292 |
0.170, 0.797 |
0.131, 0.046 |
0.3127, 0.3290 (D65) |
ST2084 |
DOLBYVISION |
0.708, 0.292 |
0.170, 0.797 |
0.131, 0.046 |
0.3127, 0.3290 (D65) |
ST2084 |
HDR10_HLG |
0.708, 0.292 |
0.170, 0.797 |
0.131, 0.046 |
0.3127, 0.3290 (D65) |
HLG |
AdobeRGB |
0.640, 0.330 |
0.210, 0.710 |
0.150, 0.060 |
0.3127, 0.3290 (D65) |
AdobeRGB |
For Opto-Electrical Transfer Function (OETF), unless otherwise specified, the values of L and E are defined as:
L - linear luminance of image \(0 \leq L \leq 1\) for conventional colorimetry
E - corresponding electrical signal (value stored in memory)
30.5.1. sRGB transfer function
30.5.2. Display-P3 EOTF
\(a = 0.948\)
\(b = 0.052\)
\(c = 0.077\)
30.5.3. Display-P3 OETF
|
Note
For most uses, the sRGB OETF is equivalent. |
30.5.4. Extended sRGB OETF
L - luminance of image is within [-0.6038, 7.5913].
E can be negative and/or > 1. That is how extended sRGB specifies colors outside the standard sRGB gamut. This means extended sRGB needs a floating point pixel format to cover the intended color range.
30.5.5. SMPTE 170M OETF
\(\alpha = 1.099 \text{ and } \beta = 0.018 \text{ for 10-bits and
less per sample system (the values given in Rec.
709)}\)
\(\alpha = 1.0993 \text{ and } \beta = 0.0181 \text{ for 12-bits
per sample system}\)
30.5.6. SMPTE ST2084 OETF (Inverse-EOTF)
where:
\(m_1 = 2610 / 4096 \times \frac{1}{4} = 0.1593017578125\)
\(m_2 = 2523 / 4096 \times 128 = 78.84375\)
\(c_1 = 3424 / 4096 = 0.8359375 = c3 - c2 + 1\)
\(c_2 = 2413 / 4096 \times 32 = 18.8515625\)
\(c_3 = 2392 / 4096 \times 32 = 18.6875\)
30.5.7. Hybrid Log Gamma (HLG)
L — is the signal normalized by the reference white level
r — is the reference white level and has a signal value of 0.5
a = 0.17883277 and b = 0.28466892 and c = 0.55991073
30.5.8. Adobe RGB (1998) OETF
\(E = L^\frac{1}{2.19921875}\)
30.5.9. Gamma 2.6 OETF
\(E = L^\frac{1}{2.6}\)
An implementation supporting this extension indicates support for these color spaces via VkSurfaceFormatKHR structures returned from vkGetPhysicalDeviceSurfaceFormatsKHR.
Specifying the supported surface color space when calling vkCreateSwapchainKHR will create a swapchain using that color space.
Vulkan requires that all implementations support the sRGB Opto-Electrical Transfer Function (OETF) and Electro-optical transfer function (EOTF) when using an SRGB pixel format. Other transfer functions, such as SMPTE 170M, must not be performed by the implementation, but can be performed by the application shader.
If pSurfaceFormats includes an entry whose value for colorSpace
is VK_COLOR_SPACE_SRGB_NONLINEAR_KHR and whose value for format
is a UNORM (or SRGB) format and the corresponding SRGB (or UNORM) format is
a color renderable format for VK_IMAGE_TILING_OPTIMAL, then
pSurfaceFormats must also contain an entry with the same value for
colorSpace and format equal to the corresponding SRGB (or UNORM)
format.
|
Note
If |
|
Note
In the initial release of the |
To query the supported presentation modes for a surface, call:
VkResult vkGetPhysicalDeviceSurfacePresentModesKHR(
VkPhysicalDevice physicalDevice,
VkSurfaceKHR surface,
uint32_t* pPresentModeCount,
VkPresentModeKHR* pPresentModes);
-
physicalDeviceis the physical device that will be associated with the swapchain to be created, as described for vkCreateSwapchainKHR. -
surfaceis the surface that will be associated with the swapchain. -
pPresentModeCountis a pointer to an integer related to the number of presentation modes available or queried, as described below. -
pPresentModesis eitherNULLor a pointer to an array of VkPresentModeKHR values, indicating the supported presentation modes.
If pPresentModes is NULL, then the number of presentation modes
supported for the given surface is returned in
pPresentModeCount.
Otherwise, pPresentModeCount must point to a variable set by the user
to the number of elements in the pPresentModes array, and on return
the variable is overwritten with the number of values actually written to
pPresentModes.
If the value of pPresentModeCount is less than the number of
presentation modes supported, at most pPresentModeCount values will be
written.
If pPresentModeCount is smaller than the number of presentation modes
supported for the given surface, VK_INCOMPLETE will be returned
instead of VK_SUCCESS to indicate that not all the available values
were returned.
Possible values of elements of the
vkGetPhysicalDeviceSurfacePresentModesKHR::pPresentModes array,
indicating the supported presentation modes for a surface, are:
typedef enum VkPresentModeKHR {
VK_PRESENT_MODE_IMMEDIATE_KHR = 0,
VK_PRESENT_MODE_MAILBOX_KHR = 1,
VK_PRESENT_MODE_FIFO_KHR = 2,
VK_PRESENT_MODE_FIFO_RELAXED_KHR = 3,
VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR = 1000111000,
VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR = 1000111001,
} VkPresentModeKHR;
-
VK_PRESENT_MODE_IMMEDIATE_KHRspecifies that the presentation engine does not wait for a vertical blanking period to update the current image, meaning this mode may result in visible tearing. No internal queuing of presentation requests is needed, as the requests are applied immediately. -
VK_PRESENT_MODE_MAILBOX_KHRspecifies that the presentation engine waits for the next vertical blanking period to update the current image. Tearing cannot be observed. An internal single-entry queue is used to hold pending presentation requests. If the queue is full when a new presentation request is received, the new request replaces the existing entry, and any images associated with the prior entry become available for re-use by the application. One request is removed from the queue and processed during each vertical blanking period in which the queue is non-empty. -
VK_PRESENT_MODE_FIFO_KHRspecifies that the presentation engine waits for the next vertical blanking period to update the current image. Tearing cannot be observed. An internal queue is used to hold pending presentation requests. New requests are appended to the end of the queue, and one request is removed from the beginning of the queue and processed during each vertical blanking period in which the queue is non-empty. This is the only value ofpresentModethat is required to be supported. -
VK_PRESENT_MODE_FIFO_RELAXED_KHRspecifies that the presentation engine generally waits for the next vertical blanking period to update the current image. If a vertical blanking period has already passed since the last update of the current image then the presentation engine does not wait for another vertical blanking period for the update, meaning this mode may result in visible tearing in this case. This mode is useful for reducing visual stutter with an application that will mostly present a new image before the next vertical blanking period, but may occasionally be late, and present a new image just after the next vertical blanking period. An internal queue is used to hold pending presentation requests. New requests are appended to the end of the queue, and one request is removed from the beginning of the queue and processed during or after each vertical blanking period in which the queue is non-empty. -
VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHRspecifies that the presentation engine and application have concurrent access to a single image, which is referred to as a shared presentable image. The presentation engine is only required to update the current image after a new presentation request is received. Therefore the application must make a presentation request whenever an update is required. However, the presentation engine may update the current image at any point, meaning this mode may result in visible tearing. -
VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHRspecifies that the presentation engine and application have concurrent access to a single image, which is referred to as a shared presentable image. The presentation engine periodically updates the current image on its regular refresh cycle. The application is only required to make one initial presentation request, after which the presentation engine must update the current image without any need for further presentation requests. The application can indicate the image contents have been updated by making a presentation request, but this does not guarantee the timing of when it will be updated. This mode may result in visible tearing if rendering to the image is not timed correctly.
The supported VkImageUsageFlagBits of the presentable images of a swapchain created for a surface may differ depending on the presentation mode, and can be determined as per the table below:
| Presentation mode | Image usage flags |
|---|---|
|
VkSurfaceCapabilitiesKHR:: |
|
VkSurfaceCapabilitiesKHR:: |
|
VkSurfaceCapabilitiesKHR:: |
|
VkSurfaceCapabilitiesKHR:: |
|
VkSharedPresentSurfaceCapabilitiesKHR:: |
|
VkSharedPresentSurfaceCapabilitiesKHR:: |
|
Note
For reference, the mode indicated by |
30.6. Device Group Queries
A logical device that represents multiple physical devices may support presenting from images on more than one physical device, or combining images from multiple physical devices.
To query these capabilities, call:
VkResult vkGetDeviceGroupPresentCapabilitiesKHR(
VkDevice device,
VkDeviceGroupPresentCapabilitiesKHR* pDeviceGroupPresentCapabilities);
-
deviceis the logical device. -
pDeviceGroupPresentCapabilitiesis a pointer to a structure of type VkDeviceGroupPresentCapabilitiesKHR that is filled with the logical device’s capabilities.
The VkDeviceGroupPresentCapabilitiesKHR structure is defined as:
typedef struct VkDeviceGroupPresentCapabilitiesKHR {
VkStructureType sType;
const void* pNext;
uint32_t presentMask[VK_MAX_DEVICE_GROUP_SIZE];
VkDeviceGroupPresentModeFlagsKHR modes;
} VkDeviceGroupPresentCapabilitiesKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
presentMaskis an array of masks, where the mask at element i is non-zero if physical device i has a presentation engine, and where bit j is set in element i if physical device i can present swapchain images from physical device j. If element i is non-zero, then bit i must be set. -
modesis a bitmask of VkDeviceGroupPresentModeFlagBitsKHR indicating which device group presentation modes are supported.
modes always has VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_BIT_KHR set.
The present mode flags are also used when presenting an image, in
VkDeviceGroupPresentInfoKHR::mode.
If a device group only includes a single physical device, then modes
must equal VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_BIT_KHR.
Bits which may be set in
VkDeviceGroupPresentCapabilitiesKHR::modes to indicate which
device group presentation modes are supported are:
typedef enum VkDeviceGroupPresentModeFlagBitsKHR {
VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_BIT_KHR = 0x00000001,
VK_DEVICE_GROUP_PRESENT_MODE_REMOTE_BIT_KHR = 0x00000002,
VK_DEVICE_GROUP_PRESENT_MODE_SUM_BIT_KHR = 0x00000004,
VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_MULTI_DEVICE_BIT_KHR = 0x00000008,
} VkDeviceGroupPresentModeFlagBitsKHR;
-
VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_BIT_KHRspecifies that any physical device with a presentation engine can present its own swapchain images. -
VK_DEVICE_GROUP_PRESENT_MODE_REMOTE_BIT_KHRspecifies that any physical device with a presentation engine can present swapchain images from any physical device in itspresentMask. -
VK_DEVICE_GROUP_PRESENT_MODE_SUM_BIT_KHRspecifies that any physical device with a presentation engine can present the sum of swapchain images from any physical devices in itspresentMask. -
VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_MULTI_DEVICE_BIT_KHRspecifies that multiple physical devices with a presentation engine can each present their own swapchain images.
typedef VkFlags VkDeviceGroupPresentModeFlagsKHR;
VkDeviceGroupPresentModeFlagsKHR is a bitmask type for setting a mask
of zero or more VkDeviceGroupPresentModeFlagBitsKHR.
Some surfaces may not be capable of using all the device group present modes.
To query the supported device group present modes for a particular surface, call:
VkResult vkGetDeviceGroupSurfacePresentModesKHR(
VkDevice device,
VkSurfaceKHR surface,
VkDeviceGroupPresentModeFlagsKHR* pModes);
-
deviceis the logical device. -
surfaceis the surface. -
pModesis a pointer to a value of typeVkDeviceGroupPresentModeFlagsKHRthat is filled with the supported device group present modes for the surface.
The modes returned by this command are not invariant, and may change in response to the surface being moved, resized, or occluded. These modes must be a subset of the modes returned by vkGetDeviceGroupPresentCapabilitiesKHR.
When using VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_MULTI_DEVICE_BIT_KHR,
the application may need to know which regions of the surface are used when
presenting locally on each physical device.
Presentation of swapchain images to this surface need only have valid
contents in the regions returned by this command.
To query a set of rectangles used in presentation on the physical device, call:
VkResult vkGetPhysicalDevicePresentRectanglesKHR(
VkPhysicalDevice physicalDevice,
VkSurfaceKHR surface,
uint32_t* pRectCount,
VkRect2D* pRects);
-
physicalDeviceis the physical device. -
surfaceis the surface. -
pRectCountis a pointer to an integer related to the number of rectangles available or queried, as described below. -
pRectsis eitherNULLor a pointer to an array ofVkRect2Dstructures.
If pRects is NULL, then the number of rectangles used when
presenting the given surface is returned in pRectCount.
Otherwise, pRectCount must point to a variable set by the user to the
number of elements in the pRects array, and on return the variable is
overwritten with the number of structures actually written to pRects.
If the value of pRectCount is less than the number of rectangles, at
most pRectCount structures will be written.
If pRectCount is smaller than the number of rectangles used for the
given surface, VK_INCOMPLETE will be returned instead of
VK_SUCCESS to indicate that not all the available values were
returned.
The values returned by this command are not invariant, and may change in response to the surface being moved, resized, or occluded.
The rectangles returned by this command must not overlap.
30.7. Display Timing Queries
Traditional game and real-time-animation applications frequently use
VK_PRESENT_MODE_FIFO_KHR so that presentable images are updated during
the vertical blanking period of a given refresh cycle (RC) of the
presentation engine’s display.
This avoids the visual anomaly known as tearing.
However, synchronizing the presentation of images with the RC does not prevent all forms of visual anomalies. Stuttering occurs when the geometry for each presentable image isn’t accurately positioned for when that image will be displayed. The geometry may appear to move too little some RCs, and too much for others. Sometimes the animation appears to freeze, when the same image is used for more than one RC.
In order to minimize stuttering, an application needs to correctly position
their geometry for when the presentable image will be displayed to the user.
To accomplish this, applications need various timing information about the
presentation engine’s display.
They need to know when presentable images were actually presented, and when
they could have been presented.
Applications also need to tell the presentation engine to display an image
no sooner than a given time.
This can allow the application’s animation to look smooth to the user, with
no stuttering.
The VK_GOOGLE_display_timing extension allows an application to satisfy
these needs.
The presentation engine’s display typically refreshes the pixels that are displayed to the user on a periodic basis. The period may be fixed or variable. In many cases, the presentation engine is associated with fixed refresh rate (FRR) display technology, with a fixed refresh rate (RR, e.g. 60Hz). In some cases, the presentation engine is associated with variable refresh rate (VRR) display technology, where each refresh cycle (RC) can vary in length. This extension treats VRR displays as if they are FRR.
To query the duration of a refresh cycle (RC) for the presentation engine’s display, call:
VkResult vkGetRefreshCycleDurationGOOGLE(
VkDevice device,
VkSwapchainKHR swapchain,
VkRefreshCycleDurationGOOGLE* pDisplayTimingProperties);
-
deviceis the device associated withswapchain. -
swapchainis the swapchain to obtain the refresh duration for. -
pDisplayTimingPropertiesis a pointer to an instance of theVkRefreshCycleDurationGOOGLEstructure.
The VkRefreshCycleDurationGOOGLE structure is defined as:
typedef struct VkRefreshCycleDurationGOOGLE {
uint64_t refreshDuration;
} VkRefreshCycleDurationGOOGLE;
-
refreshDurationis the number of nanoseconds from the start of one refresh cycle to the next.
|
Note
The rate at which an application renders and presents new images is known as
the image present rate (IPR, aka frame rate).
The inverse of IPR, or the duration between each image present, is the image
present duration (IPD).
In order to provide a smooth, stutter-free animation, an application will
want its IPD to be a multiple of In order to determine a target IPD for a display (i.e. a multiple of
Adjustments to an application’s IPD may be needed because different views of
an application’s geometry can take different amounts of time to render.
For example, looking at the sky may take less time to render than looking at
multiple, complex items in a room.
In general, it is good to not frequently change IPD, as that can cause
visual anomalies.
Adjustments to a larger IPD because of late images should happen quickly,
but adjustments to a smaller IPD should only happen if the
|
The implementation will maintain a limited amount of history of timing
information about previous presents.
Because of the asynchronous nature of the presentation engine, the timing
information for a given vkQueuePresentKHR command will become
available some time later.
These time values can be asynchronously queried, and will be returned if
available.
All time values are in nanoseconds, relative to a monotonically-increasing
clock (e.g. CLOCK_MONOTONIC (see clock_gettime(2)) on Android and Linux).
To asynchronously query the presentation engine, for newly-available timing information about one or more previous presents to a given swapchain, call:
VkResult vkGetPastPresentationTimingGOOGLE(
VkDevice device,
VkSwapchainKHR swapchain,
uint32_t* pPresentationTimingCount,
VkPastPresentationTimingGOOGLE* pPresentationTimings);
-
deviceis the device associated withswapchain. -
swapchainis the swapchain to obtain presentation timing information duration for. -
pPresentationTimingCountis a pointer to an integer related to the number ofVkPastPresentationTimingGOOGLEstructures to query, as described below. -
pPresentationTimingsis eitherNULLor a pointer to an an array ofVkPastPresentationTimingGOOGLEstructures.
If pPresentationTimings is NULL, then the number of newly-available
timing records for the given swapchain is returned in
pPresentationTimingCount.
Otherwise, pPresentationTimingCount must point to a variable set by
the user to the number of elements in the pPresentationTimings array,
and on return the variable is overwritten with the number of structures
actually written to pPresentationTimings.
If the value of pPresentationTimingCount is less than the number of
newly-available timing records, at most pPresentationTimingCount
structures will be written.
If pPresentationTimingCount is smaller than the number of
newly-available timing records for the given swapchain,
VK_INCOMPLETE will be returned instead of VK_SUCCESS to indicate
that not all the available values were returned.
The VkPastPresentationTimingGOOGLE structure is defined as:
typedef struct VkPastPresentationTimingGOOGLE {
uint32_t presentID;
uint64_t desiredPresentTime;
uint64_t actualPresentTime;
uint64_t earliestPresentTime;
uint64_t presentMargin;
} VkPastPresentationTimingGOOGLE;
-
presentIDis an application-provided value that was given to a previousvkQueuePresentKHRcommand via VkPresentTimeGOOGLE::presentID(see below). It can be used to uniquely identify a previous present with the vkQueuePresentKHR command. -
desiredPresentTimeis an application-provided value that was given to a previous vkQueuePresentKHR command via VkPresentTimeGOOGLE::desiredPresentTime. If non-zero, it was used by the application to indicate that an image not be presented any sooner thandesiredPresentTime. -
actualPresentTimeis the time when the image of theswapchainwas actually displayed. -
earliestPresentTimeis the time when the image of theswapchaincould have been displayed. This may differ fromactualPresentTimeif the application requested that the image be presented no sooner than VkPresentTimeGOOGLE::desiredPresentTime. -
presentMarginis an indication of how early thevkQueuePresentKHRcommand was processed compared to how soon it needed to be processed, and still be presented atearliestPresentTime.
The results for a given swapchain and presentID are only
returned once from vkGetPastPresentationTimingGOOGLE.
The application can use the VkPastPresentationTimingGOOGLE values to
occasionally adjust its timing.
For example, if actualPresentTime is later than expected (e.g. one
refreshDuration late), the application may increase its target IPD to
a higher multiple of refreshDuration (e.g. decrease its frame rate
from 60Hz to 30Hz).
If actualPresentTime and earliestPresentTime are consistently
different, and if presentMargin is consistently large enough, the
application may decrease its target IPD to a smaller multiple of
refreshDuration (e.g. increase its frame rate from 30Hz to 60Hz).
If actualPresentTime and earliestPresentTime are same, and if
presentMargin is consistently high, the application may delay the
start of its input-render-present loop in order to decrease the latency
between user input and the corresponding present (always leaving some margin
in case a new image takes longer to render than the previous image).
An application that desires its target IPD to always be the same as
refreshDuration, can also adjust features until
actualPresentTime is never late and presentMargin is
satisfactory.
The full VK_GOOGLE_display_timing extension semantics are described for
swapchains created with VK_PRESENT_MODE_FIFO_KHR.
For example, non-zero values of
VkPresentTimeGOOGLE::desiredPresentTime must be honored, and
vkGetPastPresentationTimingGOOGLE should return a
VkPastPresentationTimingGOOGLE structure with valid values for all
images presented with vkQueuePresentKHR.
The semantics for other present modes are as follows:
-
VK_PRESENT_MODE_IMMEDIATE_KHR. The presentation engine may ignore non-zero values ofVkPresentTimeGOOGLE::desiredPresentTimein favor of presenting immediately. The value ofVkPastPresentationTimingGOOGLE::earliestPresentTimemust be the same asVkPastPresentationTimingGOOGLE::actualPresentTime, which should be when the presentation engine displayed the image. -
VK_PRESENT_MODE_MAILBOX_KHR. The intention of using this present mode with this extension is to handle cases where an image is presented late, and the next image is presented soon enough to replace it at the next vertical blanking period. For images that are displayed to the user, the value ofVkPastPresentationTimingGOOGLE::actualPresentTimemust be when the image was displayed. For images that are not displayed to the user,vkGetPastPresentationTimingGOOGLEmay not return aVkPastPresentationTimingGOOGLEstructure, or it may return return aVkPastPresentationTimingGOOGLEstructure with the value of zero for bothVkPastPresentationTimingGOOGLE::actualPresentTimeandVkPastPresentationTimingGOOGLE::earliestPresentTime. It is possible that an application can submit images withVkPresentTimeGOOGLE::desiredPresentTimevalues such that new images may not be displayed. For example, ifVkPresentTimeGOOGLE::desiredPresentTimeis far enough in the future that an image is not presented beforevkQueuePresentKHRis called to present another image, the first image will not be displayed to the user. If the application continues to do that, the presentation may not display new images. -
VK_PRESENT_MODE_FIFO_RELAXED_KHR. For images that are presented in time to be displayed at the next vertical blanking period, the semantics are identical as forVK_PRESENT_MODE_FIFO_RELAXED_KHR. For images that are presented late, and are displayed after the start of the vertical blanking period (i.e. with tearing), the values ofVkPastPresentationTimingGOOGLEmay be treated as if the image was displayed at the start of the vertical blanking period, or may be treated the same as forVK_PRESENT_MODE_IMMEDIATE_KHR.
30.8. WSI Swapchain
A swapchain object (a.k.a.
swapchain) provides the ability to present rendering results to a surface.
Swapchain objects are represented by VkSwapchainKHR handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkSwapchainKHR)
A swapchain is an abstraction for an array of presentable images that are
associated with a surface.
The presentable images are represented by VkImage objects created by
the platform.
One image (which can be an array image for multiview/stereoscopic-3D
surfaces) is displayed at a time, but multiple images can be queued for
presentation.
An application renders to the image, and then queues the image for
presentation to the surface.
A native window cannot be associated with more than one non-retired swapchain at a time. Further, swapchains cannot be created for native windows that have a non-Vulkan graphics API surface associated with them.
|
Note
The presentation engine is an abstraction for the platform’s compositor or display engine. The presentation engine may be synchronous or asynchronous with respect to the application and/or logical device. Some implementations may use the device’s graphics queue or dedicated presentation hardware to perform presentation. |
The presentable images of a swapchain are owned by the presentation engine.
An application can acquire use of a presentable image from the presentation
engine.
Use of a presentable image must occur only after the image is returned by
vkAcquireNextImageKHR, and before it is presented by
vkQueuePresentKHR.
This includes transitioning the image layout and rendering commands.
An application can acquire use of a presentable image with
vkAcquireNextImageKHR.
After acquiring a presentable image and before modifying it, the application
must use a synchronization primitive to ensure that the presentation engine
has finished reading from the image.
The application can then transition the image’s layout, queue rendering
commands to it, etc.
Finally, the application presents the image with vkQueuePresentKHR,
which releases the acquisition of the image.
The presentation engine controls the order in which presentable images are acquired for use by the application.
|
Note
This allows the platform to handle situations which require out-of-order return of images after presentation. At the same time, it allows the application to generate command buffers referencing all of the images in the swapchain at initialization time, rather than in its main loop. |
How this all works is described below.
If a swapchain is created with presentMode set to either
VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR or
VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR, a single presentable
image can be acquired, referred to as a shared presentable image.
A shared presentable image may be concurrently accessed by the application
and the presentation engine, without transitioning the image’s layout after
it is initially presented.
-
With
VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR, the presentation engine is only required to update to the latest contents of a shared presentable image after a present. The application must callvkQueuePresentKHRto guarantee an update. However, the presentation engine may update from it at any time. -
With
VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR, the presentation engine will automatically present the latest contents of a shared presentable image during every refresh cycle. The application is only required to make one initial call tovkQueuePresentKHR, after which the presentation engine will update from it without any need for further present calls. The application can indicate the image contents have been updated by callingvkQueuePresentKHR, but this does not guarantee the timing of when updates will occur.
The presentation engine may access a shared presentable image at any time after it is first presented. To avoid tearing, an application should coordinate access with the presentation engine. This requires presentation engine timing information through platform-specific mechanisms and ensuring that color attachment writes are made available during the portion of the presentation engine’s refresh cycle they are intended for.
|
Note
The |
In order to query a swapchain’s status when rendering to a shared presentable image, call:
VkResult vkGetSwapchainStatusKHR(
VkDevice device,
VkSwapchainKHR swapchain);
-
deviceis the device associated withswapchain. -
swapchainis the swapchain to query.
The possible return values for vkGetSwapchainStatusKHR should be
interpreted as follows:
-
VK_SUCCESSspecifies the presentation engine is presenting the contents of the shared presentable image, as per the swapchain’s VkPresentModeKHR. -
VK_SUBOPTIMAL_KHRthe swapchain no longer matches the surface properties exactly, but the presentation engine is presenting the contents of the shared presentable image, as per the swapchain’s VkPresentModeKHR. -
VK_ERROR_OUT_OF_DATE_KHRthe surface has changed in such a way that it is no longer compatible with the swapchain. -
VK_ERROR_SURFACE_LOST_KHRthe surface is no longer available.
|
Note
The swapchain state may be cached by implementations, so applications
should regularly call |
To create a swapchain, call:
VkResult vkCreateSwapchainKHR(
VkDevice device,
const VkSwapchainCreateInfoKHR* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkSwapchainKHR* pSwapchain);
-
deviceis the device to create the swapchain for. -
pCreateInfois a pointer to an instance of the VkSwapchainCreateInfoKHR structure specifying the parameters of the created swapchain. -
pAllocatoris the allocator used for host memory allocated for the swapchain object when there is no more specific allocator available (see Memory Allocation). -
pSwapchainis a pointer to aVkSwapchainKHRhandle in which the created swapchain object will be returned.
The VkSwapchainCreateInfoKHR structure is defined as:
typedef struct VkSwapchainCreateInfoKHR {
VkStructureType sType;
const void* pNext;
VkSwapchainCreateFlagsKHR flags;
VkSurfaceKHR surface;
uint32_t minImageCount;
VkFormat imageFormat;
VkColorSpaceKHR imageColorSpace;
VkExtent2D imageExtent;
uint32_t imageArrayLayers;
VkImageUsageFlags imageUsage;
VkSharingMode imageSharingMode;
uint32_t queueFamilyIndexCount;
const uint32_t* pQueueFamilyIndices;
VkSurfaceTransformFlagBitsKHR preTransform;
VkCompositeAlphaFlagBitsKHR compositeAlpha;
VkPresentModeKHR presentMode;
VkBool32 clipped;
VkSwapchainKHR oldSwapchain;
} VkSwapchainCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis a bitmask of VkSwapchainCreateFlagBitsKHR indicating parameters of the swapchain creation. -
surfaceis the surface onto which the swapchain will present images. If the creation succeeds, the swapchain becomes associated withsurface. -
minImageCountis the minimum number of presentable images that the application needs. The implementation will either create the swapchain with at least that many images, or it will fail to create the swapchain. -
imageFormatis a VkFormat value specifying the format the swapchain image(s) will be created with. -
imageColorSpaceis a VkColorSpaceKHR value specifying the way the swapchain interprets image data. -
imageExtentis the size (in pixels) of the swapchain image(s). The behavior is platform-dependent if the image extent does not match the surface’scurrentExtentas returned byvkGetPhysicalDeviceSurfaceCapabilitiesKHR.
|
Note
On some platforms, it is normal that |
-
imageArrayLayersis the number of views in a multiview/stereo surface. For non-stereoscopic-3D applications, this value is 1. -
imageUsageis a bitmask of VkImageUsageFlagBits describing the intended usage of the (acquired) swapchain images. -
imageSharingModeis the sharing mode used for the image(s) of the swapchain. -
queueFamilyIndexCountis the number of queue families having access to the image(s) of the swapchain whenimageSharingModeisVK_SHARING_MODE_CONCURRENT. -
pQueueFamilyIndicesis an array of queue family indices having access to the images(s) of the swapchain whenimageSharingModeisVK_SHARING_MODE_CONCURRENT. -
preTransformis a VkSurfaceTransformFlagBitsKHR value describing the transform, relative to the presentation engine’s natural orientation, applied to the image content prior to presentation. If it does not match thecurrentTransformvalue returned byvkGetPhysicalDeviceSurfaceCapabilitiesKHR, the presentation engine will transform the image content as part of the presentation operation. -
compositeAlphais a VkCompositeAlphaFlagBitsKHR value indicating the alpha compositing mode to use when this surface is composited together with other surfaces on certain window systems. -
presentModeis the presentation mode the swapchain will use. A swapchain’s present mode determines how incoming present requests will be processed and queued internally. -
clippedspecifies whether the Vulkan implementation is allowed to discard rendering operations that affect regions of the surface that are not visible.-
If set to
VK_TRUE, the presentable images associated with the swapchain may not own all of their pixels. Pixels in the presentable images that correspond to regions of the target surface obscured by another window on the desktop, or subject to some other clipping mechanism will have undefined content when read back. Pixel shaders may not execute for these pixels, and thus any side effects they would have had will not occur.VK_TRUEvalue does not guarantee any clipping will occur, but allows more optimal presentation methods to be used on some platforms. -
If set to
VK_FALSE, presentable images associated with the swapchain will own all of the pixels they contain.
-
|
Note
Applications should set this value to |
-
oldSwapchainis VK_NULL_HANDLE, or the existing non-retired swapchain currently associated withsurface. Providing a validoldSwapchainmay aid in the resource reuse, and also allows the application to still present any images that are already acquired from it.
Upon calling vkCreateSwapchainKHR with an oldSwapchain that is
not VK_NULL_HANDLE, oldSwapchain is retired — even if creation
of the new swapchain fails.
The new swapchain is created in the non-retired state whether or not
oldSwapchain is VK_NULL_HANDLE.
Upon calling vkCreateSwapchainKHR with an oldSwapchain that is
not VK_NULL_HANDLE, any images from oldSwapchain that are not
acquired by the application may be freed by the implementation, which may
occur even if creation of the new swapchain fails.
The application can destroy oldSwapchain to free all memory
associated with oldSwapchain.
|
Note
Multiple retired swapchains can be associated with the same
After The application can continue to use a shared presentable image obtained
from |
Bits which can be set in VkSwapchainCreateInfoKHR::flags,
specifying parameters of swapchain creation, are:
typedef enum VkSwapchainCreateFlagBitsKHR {
VK_SWAPCHAIN_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT_KHR = 0x00000001,
VK_SWAPCHAIN_CREATE_PROTECTED_BIT_KHR = 0x00000002,
} VkSwapchainCreateFlagBitsKHR;
-
VK_SWAPCHAIN_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT_KHRspecifies that images created from the swapchain (i.e. with theswapchainmember of VkImageSwapchainCreateInfoKHR set to this swapchain’s handle) must useVK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT. -
VK_SWAPCHAIN_CREATE_PROTECTED_BIT_KHRspecifies that images created from the swapchain are protected images.
typedef VkFlags VkSwapchainCreateFlagsKHR;
VkSwapchainCreateFlagsKHR is a bitmask type for setting a mask of zero
or more VkSwapchainCreateFlagBitsKHR.
If the pNext chain of VkSwapchainCreateInfoKHR includes a
VkDeviceGroupSwapchainCreateInfoKHR structure, then that structure
includes a set of device group present modes that the swapchain can be used
with.
The VkDeviceGroupSwapchainCreateInfoKHR structure is defined as:
typedef struct VkDeviceGroupSwapchainCreateInfoKHR {
VkStructureType sType;
const void* pNext;
VkDeviceGroupPresentModeFlagsKHR modes;
} VkDeviceGroupSwapchainCreateInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
modesis a bitfield of modes that the swapchain can be used with.
If this structure is not present, modes is considered to be
VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_BIT_KHR.
To enable surface counters when creating a swapchain, add
VkSwapchainCounterCreateInfoEXT to the pNext chain of
VkSwapchainCreateInfoKHR.
VkSwapchainCounterCreateInfoEXT is defined as:
typedef struct VkSwapchainCounterCreateInfoEXT {
VkStructureType sType;
const void* pNext;
VkSurfaceCounterFlagsEXT surfaceCounters;
} VkSwapchainCounterCreateInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
surfaceCountersis a bitmask of VkSurfaceCounterFlagBitsEXT specifying surface counters to enable for the swapchain.
The requested counters become active when the first presentation command for the associated swapchain is processed by the presentation engine. To query the value of an active counter, use:
VkResult vkGetSwapchainCounterEXT(
VkDevice device,
VkSwapchainKHR swapchain,
VkSurfaceCounterFlagBitsEXT counter,
uint64_t* pCounterValue);
-
deviceis theVkDeviceassociated withswapchain. -
swapchainis the swapchain from which to query the counter value. -
counteris the counter to query. -
pCounterValuewill return the current value of the counter.
If a counter is not available because the swapchain is out of date, the
implementation may return VK_ERROR_OUT_OF_DATE_KHR.
As mentioned above, if vkCreateSwapchainKHR succeeds, it will return a
handle to a swapchain that contains an array of at least minImageCount
presentable images.
While acquired by the application, presentable images can be used in any
way that equivalent non-presentable images can be used.
A presentable image is equivalent to a non-presentable image created with
the following VkImageCreateInfo parameters:
VkImageCreateInfo Field |
Value |
|---|---|
|
all other bits are unset |
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|
|
1 |
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The surface must not be destroyed until after the swapchain is
destroyed.
If oldSwapchain is VK_NULL_HANDLE, and the native window
referred to by surface is already associated with a Vulkan swapchain,
VK_ERROR_NATIVE_WINDOW_IN_USE_KHR must be returned.
If the native window referred to by surface is already associated with
a non-Vulkan graphics API surface, VK_ERROR_NATIVE_WINDOW_IN_USE_KHR
must be returned.
The native window referred to by surface must not become associated
with a non-Vulkan graphics API surface before all associated Vulkan
swapchains have been destroyed.
Like core functions, several WSI functions, including
vkCreateSwapchainKHR return VK_ERROR_DEVICE_LOST if the logical
device was lost.
See Lost Device.
As with most core objects, VkSwapchainKHR is a child of the device and
is affected by the lost state; it must be destroyed before destroying the
VkDevice.
However, VkSurfaceKHR is not a child of any VkDevice and is not
otherwise affected by the lost device.
After successfully recreating a VkDevice, the same VkSurfaceKHR
can be used to create a new VkSwapchainKHR, provided the previous one
was destroyed.
|
Note
As mentioned in Lost Device, after a lost
device event, the |
To destroy a swapchain object call:
void vkDestroySwapchainKHR(
VkDevice device,
VkSwapchainKHR swapchain,
const VkAllocationCallbacks* pAllocator);
-
deviceis theVkDeviceassociated withswapchain. -
swapchainis the swapchain to destroy. -
pAllocatoris the allocator used for host memory allocated for the swapchain object when there is no more specific allocator available (see Memory Allocation).
The application must not destroy a swapchain until after completion of all
outstanding operations on images that were acquired from the swapchain.
swapchain and all associated VkImage handles are destroyed, and
must not be acquired or used any more by the application.
The memory of each VkImage will only be freed after that image is no
longer used by the presentation engine.
For example, if one image of the swapchain is being displayed in a window,
the memory for that image may not be freed until the window is destroyed,
or another swapchain is created for the window.
Destroying the swapchain does not invalidate the parent VkSurfaceKHR,
and a new swapchain can be created with it.
When a swapchain associated with a display surface is destroyed, if the image most recently presented to the display surface is from the swapchain being destroyed, then either any display resources modified by presenting images from any swapchain associated with the display surface must be reverted by the implementation to their state prior to the first present performed on one of these swapchains, or such resources must be left in their current state.
To obtain the array of presentable images associated with a swapchain, call:
VkResult vkGetSwapchainImagesKHR(
VkDevice device,
VkSwapchainKHR swapchain,
uint32_t* pSwapchainImageCount,
VkImage* pSwapchainImages);
-
deviceis the device associated withswapchain. -
swapchainis the swapchain to query. -
pSwapchainImageCountis a pointer to an integer related to the number of presentable images available or queried, as described below. -
pSwapchainImagesis eitherNULLor a pointer to an array ofVkImagehandles.
If pSwapchainImages is NULL, then the number of presentable images
for swapchain is returned in pSwapchainImageCount.
Otherwise, pSwapchainImageCount must point to a variable set by the
user to the number of elements in the pSwapchainImages array, and on
return the variable is overwritten with the number of structures actually
written to pSwapchainImages.
If the value of pSwapchainImageCount is less than the number of
presentable images for swapchain, at most pSwapchainImageCount
structures will be written.
If pSwapchainImageCount is smaller than the number of presentable
images for swapchain, VK_INCOMPLETE will be returned instead of
VK_SUCCESS to indicate that not all the available values were
returned.
|
Note
By knowing all presentable images used in the swapchain, the application can create command buffers that reference these images prior to entering its main rendering loop. |
The implementation will have already allocated and bound the memory backing
the VkImages returned by vkGetSwapchainImagesKHR.
The memory for each image will not alias with the memory for other images or
with any VkDeviceMemory object.
As such, performing any operation affecting the binding of memory to a
presentable image results in undefined behavior.
All presentable images are initially in the VK_IMAGE_LAYOUT_UNDEFINED
layout, thus before using presentable images, the application must
transition them to a valid layout for the intended use.
Further, the lifetime of presentable images is controlled by the implementation so destroying a presentable image with vkDestroyImage results in undefined behavior. See vkDestroySwapchainKHR for further details on the lifetime of presentable images.
Images can also be created by using vkCreateImage with
VkImageSwapchainCreateInfoKHR and bound to swapchain memory using
vkBindImageMemory2KHR with VkBindImageMemorySwapchainInfoKHR.
These images can be used anywhere swapchain images are used, and are useful
in logical devices with multiple physical devices to create peer memory
bindings of swapchain memory.
These images and bindings have no effect on what memory is presented.
Unlike images retrieved from vkGetSwapchainImagesKHR, these images
must be destroyed with vkDestroyImage.
To acquire an available presentable image to use, and retrieve the index of that image, call:
VkResult vkAcquireNextImageKHR(
VkDevice device,
VkSwapchainKHR swapchain,
uint64_t timeout,
VkSemaphore semaphore,
VkFence fence,
uint32_t* pImageIndex);
-
deviceis the device associated withswapchain. -
swapchainis the non-retired swapchain from which an image is being acquired. -
timeoutspecifies how long the function waits, in nanoseconds, if no image is available. -
semaphoreis VK_NULL_HANDLE or a semaphore to signal. -
fenceis VK_NULL_HANDLE or a fence to signal. -
pImageIndexis a pointer to auint32_tthat is set to the index of the next image to use (i.e. an index into the array of images returned byvkGetSwapchainImagesKHR).
When successful, vkAcquireNextImageKHR acquires a presentable image
from swapchain that an application can use, and sets
pImageIndex to the index of that image within the swapchain.
The presentation engine may not have finished reading from the image at the
time it is acquired, so the application must use semaphore and/or
fence to ensure that the image layout and contents are not modified
until the presentation engine reads have completed.
The order in which images are acquired is implementation-dependent, and may
be different than the order the images were presented.
If timeout is zero, then vkAcquireNextImageKHR does not wait,
and will either successfully acquire an image, or fail and return
VK_NOT_READY if no image is available.
If the specified timeout period expires before an image is acquired,
vkAcquireNextImageKHR returns VK_TIMEOUT.
If timeout is UINT64_MAX, the timeout period is treated as
infinite, and vkAcquireNextImageKHR will block until an image is
acquired or an error occurs.
An image will eventually be acquired if the number of images that the
application has currently acquired (but not yet presented) is less than or
equal to the difference between the number of images in swapchain and
the value of VkSurfaceCapabilitiesKHR::minImageCount.
If the number of currently acquired images is greater than this,
vkAcquireNextImage should not be called; if it is, timeout
must not be UINT64_MAX.
If an image is acquired successfully, vkAcquireNextImage must either
return VK_SUCCESS, or VK_SUBOPTIMAL_KHR if the swapchain no
longer matches the surface properties exactly, but can still be used for
presentation.
|
Note
This may happen, for example, if the platform surface has been resized but the platform is able to scale the presented images to the new size to produce valid surface updates. It is up to the application to decide whether it prefers to continue using the current swapchain in this state, or to re-create the swapchain to better match the platform surface properties. |
If the swapchain images no longer match native surface properties, either
VK_SUBOPTIMAL_KHR or VK_ERROR_OUT_OF_DATE_KHR must be returned.
If VK_ERROR_OUT_OF_DATE_KHR is returned, no image is acquired and
attempts to present previously acquired images to the swapchain will also
fail with VK_ERROR_OUT_OF_DATE_KHR.
Applications need to create a new swapchain for the surface to continue
presenting if VK_ERROR_OUT_OF_DATE_KHR is returned.
If device loss occurs (see Lost Device) before
the timeout has expired, vkAcquireNextImageKHR must return in finite
time with either one of the allowed success codes, or
VK_ERROR_DEVICE_LOST.
If semaphore is not VK_NULL_HANDLE, the semaphore must be
unsignaled, with no signal or wait operations pending.
It will become signaled when the application can use the image.
|
Note
Use of |
If fence is not equal to VK_NULL_HANDLE, the fence must be
unsignaled, with no signal operations pending.
It will become signaled when the application can use the image.
|
Note
Applications should not rely on |
An application must wait until either the semaphore or fence is
signaled before accessing the image’s data.
|
Note
When the presentable image will be accessed by some stage S, the recommended idiom for ensuring correct synchronization is:
|
After a successful return, the image indicated by pImageIndex and its
data will be unmodified compared to when it was presented.
|
Note
Exclusive ownership of presentable images corresponding to a swapchain
created with |
The possible return values for vkAcquireNextImageKHR depend on the
timeout provided:
-
VK_SUCCESSis returned if an image became available. -
VK_ERROR_SURFACE_LOST_KHRif the surface becomes no longer available. -
VK_NOT_READYis returned iftimeoutis zero and no image was available. -
VK_TIMEOUTis returned iftimeoutis greater than zero and less thanUINT64_MAX, and no image became available within the time allowed. -
VK_SUBOPTIMAL_KHRis returned if an image became available, and the swapchain no longer matches the surface properties exactly, but can still be used to present to the surface successfully.
|
Note
This may happen, for example, if the platform surface has been resized but the platform is able to scale the presented images to the new size to produce valid surface updates. It is up to the application to decide whether it prefers to continue using the current swapchain indefinitely or temporarily in this state, or to re-create the swapchain to better match the platform surface properties. |
-
VK_ERROR_OUT_OF_DATE_KHRis returned if the surface has changed in such a way that it is no longer compatible with the swapchain, and further presentation requests using the swapchain will fail. Applications must query the new surface properties and recreate their swapchain if they wish to continue presenting to the surface.
If the native surface and presented image sizes no longer match,
presentation may fail.
If presentation does succeed, parts of the native surface may be undefined,
parts of the presented image may have been clipped before presentation,
and/or the image may have been scaled (uniformly or not uniformly) before
presentation.
It is the application’s responsibility to detect surface size changes and
react appropriately.
If presentation fails because of a mismatch in the surface and presented
image sizes, a VK_ERROR_OUT_OF_DATE_KHR error will be returned.
To acquire an available presentable image to use, and retrieve the index of that image, call:
VkResult vkAcquireNextImage2KHR(
VkDevice device,
const VkAcquireNextImageInfoKHR* pAcquireInfo,
uint32_t* pImageIndex);
-
deviceis the device associated withswapchain. -
pAcquireInfois a pointer to a structure of type VkAcquireNextImageInfoKHR containing parameters of the acquire. -
pImageIndexis a pointer to auint32_tthat is set to the index of the next image to use.
The VkAcquireNextImageInfoKHR structure is defined as:
typedef struct VkAcquireNextImageInfoKHR {
VkStructureType sType;
const void* pNext;
VkSwapchainKHR swapchain;
uint64_t timeout;
VkSemaphore semaphore;
VkFence fence;
uint32_t deviceMask;
} VkAcquireNextImageInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
swapchainis a non-retired swapchain from which an image is acquired. -
timeoutspecifies how long the function waits, in nanoseconds, if no image is available. -
semaphoreisVK_NULL_HANDLEor a semaphore to signal. -
fenceisVK_NULL_HANDLEor a fence to signal. -
deviceMaskis a mask of physical devices for which the swapchain image will be ready to use when the semaphore or fence is signaled.
If vkAcquireNextImageKHR is used, the device mask is considered to include all physical devices in the logical device.
|
Note
vkAcquireNextImage2KHR signals at most one semaphore, even if the
application requests waiting for multiple physical devices to be ready via
the |
After queueing all rendering commands and transitioning the image to the correct layout, to queue an image for presentation, call:
VkResult vkQueuePresentKHR(
VkQueue queue,
const VkPresentInfoKHR* pPresentInfo);
-
queueis a queue that is capable of presentation to the target surface’s platform on the same device as the image’s swapchain. -
pPresentInfois a pointer to an instance of the VkPresentInfoKHR structure specifying the parameters of the presentation.
|
Note
There is no requirement for an application to present images in the same order that they were acquired - applications can arbitrarily present any image that is currently acquired. |
Any writes to memory backing the images referenced by the
pImageIndices and pSwapchains members of pPresentInfo,
that are available before vkQueuePresentKHR is executed, are
automatically made visible to the read access performed by the presentation
engine.
This automatic visibility operation for an image happens-after the semaphore
signal operation, and happens-before the presentation engine accesses the
image.
Queueing an image for presentation defines a set of queue operations, including waiting on the semaphores and submitting a presentation request to the presentation engine. However, the scope of this set of queue operations does not include the actual processing of the image by the presentation engine.
If vkQueuePresentKHR fails to enqueue the corresponding set of queue
operations, it may return VK_ERROR_OUT_OF_HOST_MEMORY or
VK_ERROR_OUT_OF_DEVICE_MEMORY.
If it does, the implementation must ensure that the state and contents of
any resources or synchronization primitives referenced is unaffected by the
call or its failure.
If vkQueuePresentKHR fails in such a way that the implementation is
unable to make that guarantee, the implementation must return
VK_ERROR_DEVICE_LOST.
However, if the presentation request is rejected by the presentation engine
with an error VK_ERROR_OUT_OF_DATE_KHR or
VK_ERROR_SURFACE_LOST_KHR, the set of queue operations are still
considered to be enqueued and thus any semaphore to be waited on gets
unsignaled when the corresponding queue operation is complete.
The VkPresentInfoKHR structure is defined as:
typedef struct VkPresentInfoKHR {
VkStructureType sType;
const void* pNext;
uint32_t waitSemaphoreCount;
const VkSemaphore* pWaitSemaphores;
uint32_t swapchainCount;
const VkSwapchainKHR* pSwapchains;
const uint32_t* pImageIndices;
VkResult* pResults;
} VkPresentInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
waitSemaphoreCountis the number of semaphores to wait for before issuing the present request. The number may be zero. -
pWaitSemaphores, if notNULL, is an array ofVkSemaphoreobjects withwaitSemaphoreCountentries, and specifies the semaphores to wait for before issuing the present request. -
swapchainCountis the number of swapchains being presented to by this command. -
pSwapchainsis an array ofVkSwapchainKHRobjects withswapchainCountentries. A given swapchain must not appear in this list more than once. -
pImageIndicesis an array of indices into the array of each swapchain’s presentable images, withswapchainCountentries. Each entry in this array identifies the image to present on the corresponding entry in thepSwapchainsarray. -
pResultsis an array of VkResult typed elements withswapchainCountentries. Applications that do not need per-swapchain results can useNULLforpResults. If non-NULL, each entry inpResultswill be set to the VkResult for presenting the swapchain corresponding to the same index inpSwapchains.
Before an application can present an image, the image’s layout must be
transitioned to the VK_IMAGE_LAYOUT_PRESENT_SRC_KHR
layout, or for a shared presentable image the
VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR
layout.
|
Note
When transitioning the image to
|
When the VK_KHR_incremental_present extension is enabled, additional
fields can be specified that allow an application to specify that only
certain rectangular regions of the presentable images of a swapchain are
changed.
This is an optimization hint that a presentation engine may use to only
update the region of a surface that is actually changing.
The application still must ensure that all pixels of a presented image
contain the desired values, in case the presentation engine ignores this
hint.
An application can provide this hint by including the
VkPresentRegionsKHR structure in the pNext chain of the
VkPresentInfoKHR structure.
The VkPresentRegionsKHR structure is defined as:
typedef struct VkPresentRegionsKHR {
VkStructureType sType;
const void* pNext;
uint32_t swapchainCount;
const VkPresentRegionKHR* pRegions;
} VkPresentRegionsKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
swapchainCountis the number of swapchains being presented to by this command. -
pRegionsisNULLor a pointer to an array ofVkPresentRegionKHRelements withswapchainCountentries. If notNULL, each element ofpRegionscontains the region that has changed since the last present to the swapchain in the corresponding entry in theVkPresentInfoKHR::pSwapchainsarray.
For a given image and swapchain, the region to present is specified by the
VkPresentRegionKHR structure, which is defined as:
typedef struct VkPresentRegionKHR {
uint32_t rectangleCount;
const VkRectLayerKHR* pRectangles;
} VkPresentRegionKHR;
-
rectangleCountis the number of rectangles inpRectangles, or zero if the entire image has changed and should be presented. -
pRectanglesis eitherNULLor a pointer to an array ofVkRectLayerKHRstructures. TheVkRectLayerKHRstructure is the framebuffer coordinates, plus layer, of a portion of a presentable image that has changed and must be presented. If non-NULL, each entry inpRectanglesis a rectangle of the given image that has changed since the last image was presented to the given swapchain.
The VkRectLayerKHR structure is defined as:
typedef struct VkRectLayerKHR {
VkOffset2D offset;
VkExtent2D extent;
uint32_t layer;
} VkRectLayerKHR;
-
offsetis the origin of the rectangle, in pixels. -
extentis the size of the rectangle, in pixels. -
layeris the layer of the image. For images with only one layer, the value oflayermust be 0.
Some platforms allow the size of a surface to change, and then scale the
pixels of the image to fit the surface.
VkRectLayerKHR specifies pixels of the swapchain’s image(s), which
will be constant for the life of the swapchain.
When the VK_KHR_display_swapchain extension is enabled additional fields
can be specified when presenting an image to a swapchain by setting
VkPresentInfoKHR::pNext to point to an instance of the
VkDisplayPresentInfoKHR structure.
The VkDisplayPresentInfoKHR structure is defined as:
typedef struct VkDisplayPresentInfoKHR {
VkStructureType sType;
const void* pNext;
VkRect2D srcRect;
VkRect2D dstRect;
VkBool32 persistent;
} VkDisplayPresentInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
srcRectis a rectangular region of pixels to present. It must be a subset of the image being presented. IfVkDisplayPresentInfoKHRis not specified, this region will be assumed to be the entire presentable image. -
dstRectis a rectangular region within the visible region of the swapchain’s display mode. IfVkDisplayPresentInfoKHRis not specified, this region will be assumed to be the entire visible region of the visible region of the swapchain’s mode. If the specified rectangle is a subset of the display mode’s visible region, content from display planes below the swapchain’s plane will be visible outside the rectangle. If there are no planes below the swapchain’s, the area outside the specified rectangle will be black. If portions of the specified rectangle are outside of the display’s visible region, pixels mapping only to those portions of the rectangle will be discarded. -
persistent: If this isVK_TRUE, the display engine will enable buffered mode on displays that support it. This allows the display engine to stop sending content to the display until a new image is presented. The display will instead maintain a copy of the last presented image. This allows less power to be used, but may increase presentation latency. IfVkDisplayPresentInfoKHRis not specified, persistent mode will not be used.
If the extent of the srcRect and dstRect are not equal, the
presented pixels will be scaled accordingly.
If the pNext chain of VkPresentInfoKHR includes a
VkDeviceGroupPresentInfoKHR structure, then that structure includes an
array of device masks and a device group present mode.
The VkDeviceGroupPresentInfoKHR structure is defined as:
typedef struct VkDeviceGroupPresentInfoKHR {
VkStructureType sType;
const void* pNext;
uint32_t swapchainCount;
const uint32_t* pDeviceMasks;
VkDeviceGroupPresentModeFlagBitsKHR mode;
} VkDeviceGroupPresentInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
swapchainCountis zero or the number of elements inpDeviceMasks. -
pDeviceMasksis an array of device masks, one for each element of VkPresentInfoKHR::pSwapchains. -
modeis the device group present mode that will be used for this present.
If mode is VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_BIT_KHR, then each
element of pDeviceMasks selects which instance of the swapchain image
is presented.
Each element of pDeviceMasks must have exactly one bit set, and the
corresponding physical device must have a presentation engine as reported
by VkDeviceGroupPresentCapabilitiesKHR.
If mode is VK_DEVICE_GROUP_PRESENT_MODE_REMOTE_BIT_KHR, then
each element of pDeviceMasks selects which instance of the swapchain
image is presented.
Each element of pDeviceMasks must have exactly one bit set, and some
physical device in the logical device must include that bit in its
VkDeviceGroupPresentCapabilitiesKHR::presentMask.
If mode is VK_DEVICE_GROUP_PRESENT_MODE_SUM_BIT_KHR, then each
element of pDeviceMasks selects which instances of the swapchain image
are component-wise summed and the sum of those images is presented.
If the sum in any component is outside the representable range, the value of
that component is undefined.
Each element of pDeviceMasks must have a value for which all set bits
are set in one of the elements of
VkDeviceGroupPresentCapabilitiesKHR::presentMask.
If mode is
VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_MULTI_DEVICE_BIT_KHR, then each
element of pDeviceMasks selects which instance(s) of the swapchain
images are presented.
For each bit set in each element of pDeviceMasks, the corresponding
physical device must have a presentation engine as reported by
VkDeviceGroupPresentCapabilitiesKHR.
If VkDeviceGroupPresentInfoKHR is not provided or swapchainCount
is zero then the masks are considered to be 1.
If VkDeviceGroupPresentInfoKHR is not provided, mode is
considered to be VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_BIT_KHR.
When the VK_GOOGLE_display_timing extension is enabled, additional
fields can be specified that allow an application to specify the earliest
time that an image should be displayed.
This allows an application to avoid stutter that is caused by an image being
displayed earlier than planned.
Such stuttering can occur with both fixed and variable-refresh-rate
displays, because stuttering occurs when the geometry is not correctly
positioned for when the image is displayed.
An application can instruct the presentation engine that an image should
not be displayed earlier than a specified time by including the
VkPresentTimesInfoGOOGLE structure in the pNext chain of the
VkPresentInfoKHR structure.
The VkPresentTimesInfoGOOGLE structure is defined as:
typedef struct VkPresentTimesInfoGOOGLE {
VkStructureType sType;
const void* pNext;
uint32_t swapchainCount;
const VkPresentTimeGOOGLE* pTimes;
} VkPresentTimesInfoGOOGLE;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
swapchainCountis the number of swapchains being presented to by this command. -
pTimesisNULLor a pointer to an array ofVkPresentTimeGOOGLEelements withswapchainCountentries. If notNULL, each element ofpTimescontains the earliest time to present the image corresponding to the entry in theVkPresentInfoKHR::pImageIndicesarray.
The VkPresentTimeGOOGLE structure is defined as:
typedef struct VkPresentTimeGOOGLE {
uint32_t presentID;
uint64_t desiredPresentTime;
} VkPresentTimeGOOGLE;
-
presentIDis an application-provided identification value, that can be used with the results of vkGetPastPresentationTimingGOOGLE, in order to uniquely identify this present. In order to be useful to the application, it should be unique within some period of time that is meaningful to the application. -
desiredPresentTimespecifies that the image given should not be displayed to the user any earlier than this time.desiredPresentTimeis a time in nanoseconds, relative to a monotonically-increasing clock (e.g.CLOCK_MONOTONIC(see clock_gettime(2)) on Android and Linux). A value of zero specifies that the presentation engine may display the image at any time. This is useful when the application desires to providepresentID, but doesn’t need a specificdesiredPresentTime.
vkQueuePresentKHR, releases the acquisition of the images referenced
by imageIndices.
The queue family corresponding to the queue vkQueuePresentKHR is
executed on must have ownership of the presented images as defined in
Resource Sharing.
vkQueuePresentKHR does not alter the queue family ownership, but the
presented images must not be used again before they have been reacquired
using vkAcquireNextImageKHR.
The processing of the presentation happens in issue order with other queue operations, but semaphores have to be used to ensure that prior rendering and other commands in the specified queue complete before the presentation begins. The presentation command itself does not delay processing of subsequent commands on the queue, however, presentation requests sent to a particular queue are always performed in order. Exact presentation timing is controlled by the semantics of the presentation engine and native platform in use.
If an image is presented to a swapchain created from a display surface, the mode of the associated display will be updated, if necessary, to match the mode specified when creating the display surface. The mode switch and presentation of the specified image will be performed as one atomic operation.
The result codes VK_ERROR_OUT_OF_DATE_KHR and VK_SUBOPTIMAL_KHR
have the same meaning when returned by vkQueuePresentKHR as they do
when returned by vkAcquireNextImageKHR.
If multiple swapchains are presented, the result code is determined applying
the following rules in order:
-
If the device is lost,
VK_ERROR_DEVICE_LOSTis returned. -
If any of the target surfaces are no longer available the error
VK_ERROR_SURFACE_LOST_KHRis returned. -
If any of the presents would have a result of
VK_ERROR_OUT_OF_DATE_KHRif issued separately thenVK_ERROR_OUT_OF_DATE_KHRis returned. -
If any of the presents would have a result of
VK_SUBOPTIMAL_KHRif issued separately thenVK_SUBOPTIMAL_KHRis returned. -
Otherwise
VK_SUCCESSis returned.
Presentation is a read-only operation that will not affect the content of
the presentable images.
Upon reacquiring the image and transitioning it away from the
VK_IMAGE_LAYOUT_PRESENT_SRC_KHR layout, the contents will be the same
as they were prior to transitioning the image to the present source layout
and presenting it.
However, if a mechanism other than Vulkan is used to modify the platform
window associated with the swapchain, the content of all presentable images
in the swapchain becomes undefined.
|
Note
The application can continue to present any acquired images from a retired
swapchain as long as the swapchain has not entered a state that causes
vkQueuePresentKHR to return |
30.9. Hdr Metadata
To improve color reproduction of content it is useful to have information
that can be used to better reproduce the colors as seen on the mastering
display.
That information can be provided to an implementation by calling
vkSetHdrMetadataEXT.
The metadata will be applied to the specified VkSwapchainKHR objects
at the next vkQueuePresentKHR call using that VkSwapchainKHR
object.
The metadata will persist until a subsequent vkSetHdrMetadataEXT
changes it.
The definitions below are from the associated SMPTE 2086, CTA 861.3 and CIE
15:2004 specifications.
The definition of vkSetHdrMetadataEXT is:
void vkSetHdrMetadataEXT(
VkDevice device,
uint32_t swapchainCount,
const VkSwapchainKHR* pSwapchains,
const VkHdrMetadataEXT* pMetadata);
-
deviceis the logical device where the swapchain(s) were created. -
swapchainCountis the number of swapchains included inpSwapchains. -
pSwapchainsis a pointer to the array ofswapchainCountVkSwapchainKHRhandles. -
pMetadatais a pointer to the array ofswapchainCountVkHdrMetadataEXTstructures.
typedef struct VkXYColorEXT {
float x;
float y;
} VkXYColorEXT;
Chromaticity coordinates x and y are as specified in CIE 15:2004 “Calculation of chromaticity coordinates” (Section 7.3) and are limited to between 0 and 1 for real colors for the mastering display.
typedef struct VkHdrMetadataEXT {
VkStructureType sType;
const void* pNext;
VkXYColorEXT displayPrimaryRed;
VkXYColorEXT displayPrimaryGreen;
VkXYColorEXT displayPrimaryBlue;
VkXYColorEXT whitePoint;
float maxLuminance;
float minLuminance;
float maxContentLightLevel;
float maxFrameAverageLightLevel;
} VkHdrMetadataEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
displayPrimaryRedis the mastering display’s red primary in chromaticity coordinates -
displayPrimaryGreenis the mastering display’s green primary in chromaticity coordinates -
displayPrimaryBlueis the mastering display’s blue primary in chromaticity coordinates -
whitePointis the mastering display’s white-point in chromaticity coordinates -
maxLuminanceis the maximum luminance of the mastering display in nits -
minLuminanceis the minimum luminance of the mastering display in nits -
maxContentLightLevelis content’s maximum luminance in nits -
maxFrameAverageLightLevelis the maximum frame average light level in nits
|
Note
The validity and use of this data is outside the scope of Vulkan and thus no Valid Usage is given. |
31. Extended Functionality
Additional functionality may be provided by layers or extensions. A layer cannot add or modify Vulkan commands, while an extension may do so.
The set of layers to enable is specified when creating an instance, and those layers are able to intercept any Vulkan command dispatched to that instance or any of its child objects.
Extensions can operate at either the instance or device extension scope. Enabled instance extensions are able to affect the operation of the instance and any of its child objects, while device extensions may only be available on a subset of physical devices, must be individually enabled per-device, and only affect the operation of the devices where they are enabled.
|
Note
Examples of these might be:
|
31.1. Layers
When a layer is enabled, it inserts itself into the call chain for Vulkan commands the layer is interested in. A common use of layers is to validate application behavior during development. For example, the implementation will not check that Vulkan enums used by the application fall within allowed ranges. Instead, a validation layer would do those checks and flag issues. This avoids a performance penalty during production use of the application because those layers would not be enabled in production.
Vulkan layers may wrap object handles (i.e. return a different handle value to the application than that generated by the implementation). This is generally discouraged, as it increases the probability of incompatibilities with new extensions. The validation layers wrap handles in order to track the proper use and destruction of each object. See the “Vulkan Loader Specification and Architecture Overview” document for additional information.
To query the available layers, call:
VkResult vkEnumerateInstanceLayerProperties(
uint32_t* pPropertyCount,
VkLayerProperties* pProperties);
-
pPropertyCountis a pointer to an integer related to the number of layer properties available or queried, as described below. -
pPropertiesis eitherNULLor a pointer to an array of VkLayerProperties structures.
If pProperties is NULL, then the number of layer properties
available is returned in pPropertyCount.
Otherwise, pPropertyCount must point to a variable set by the user to
the number of elements in the pProperties array, and on return the
variable is overwritten with the number of structures actually written to
pProperties.
If pPropertyCount is less than the number of layer properties
available, at most pPropertyCount structures will be written.
If pPropertyCount is smaller than the number of layers available,
VK_INCOMPLETE will be returned instead of VK_SUCCESS, to
indicate that not all the available layer properties were returned.
The list of available layers may change at any time due to actions outside
of the Vulkan implementation, so two calls to
vkEnumerateInstanceLayerProperties with the same parameters may
return different results, or retrieve different pPropertyCount values
or pProperties contents.
Once an instance has been created, the layers enabled for that instance will
continue to be enabled and valid for the lifetime of that instance, even if
some of them become unavailable for future instances.
The VkLayerProperties structure is defined as:
typedef struct VkLayerProperties {
char layerName[VK_MAX_EXTENSION_NAME_SIZE];
uint32_t specVersion;
uint32_t implementationVersion;
char description[VK_MAX_DESCRIPTION_SIZE];
} VkLayerProperties;
-
layerNameis a null-terminated UTF-8 string specifying the name of the layer. Use this name in theppEnabledLayerNamesarray passed in the VkInstanceCreateInfo structure to enable this layer for an instance. -
specVersionis the Vulkan version the layer was written to, encoded as described in the API Version Numbers and Semantics section. -
implementationVersionis the version of this layer. It is an integer, increasing with backward compatible changes. -
descriptionis a null-terminated UTF-8 string providing additional details that can be used by the application to identify the layer.
To enable a layer, the name of the layer should be added to the
ppEnabledLayerNames member of VkInstanceCreateInfo when creating
a VkInstance.
Loader implementations may provide mechanisms outside the Vulkan API for
enabling specific layers.
Layers enabled through such a mechanism are implicitly enabled, while
layers enabled by including the layer name in the ppEnabledLayerNames
member of VkInstanceCreateInfo are explicitly enabled.
Except where otherwise specified, implicitly enabled and explicitly enabled
layers differ only in the way they are enabled.
Explicitly enabling a layer that is implicitly enabled has no additional
effect.
31.1.1. Device Layer Deprecation
Previous versions of this specification distinguished between instance and
device layers.
Instance layers were only able to intercept commands that operate on
VkInstance and VkPhysicalDevice, except they were not able to
intercept vkCreateDevice.
Device layers were enabled for individual devices when they were created,
and could only intercept commands operating on that device or its child
objects.
Device-only layers are now deprecated, and this specification no longer distinguishes between instance and device layers. Layers are enabled during instance creation, and are able to intercept all commands operating on that instance or any of its child objects. At the time of deprecation there were no known device-only layers and no compelling reason to create one.
In order to maintain compatibility with implementations released prior to
device-layer deprecation, applications should still enumerate and enable
device layers.
The behavior of vkEnumerateDeviceLayerProperties and valid usage of
the ppEnabledLayerNames member of VkDeviceCreateInfo maximizes
compatibility with applications written to work with the previous
requirements.
To enumerate device layers, call:
VkResult vkEnumerateDeviceLayerProperties(
VkPhysicalDevice physicalDevice,
uint32_t* pPropertyCount,
VkLayerProperties* pProperties);
-
pPropertyCountis a pointer to an integer related to the number of layer properties available or queried. -
pPropertiesis eitherNULLor a pointer to an array of VkLayerProperties structures.
If pProperties is NULL, then the number of layer properties
available is returned in pPropertyCount.
Otherwise, pPropertyCount must point to a variable set by the user to
the number of elements in the pProperties array, and on return the
variable is overwritten with the number of structures actually written to
pProperties.
If pPropertyCount is less than the number of layer properties
available, at most pPropertyCount structures will be written.
If pPropertyCount is smaller than the number of layers available,
VK_INCOMPLETE will be returned instead of VK_SUCCESS, to
indicate that not all the available layer properties were returned.
The list of layers enumerated by vkEnumerateDeviceLayerProperties
must be exactly the sequence of layers enabled for the instance.
The members of VkLayerProperties for each enumerated layer must be
the same as the properties when the layer was enumerated by
vkEnumerateInstanceLayerProperties.
The ppEnabledLayerNames and enabledLayerCount members of
VkDeviceCreateInfo are deprecated and their values must be ignored by
implementations.
However, for compatibility, only an empty list of layers or a list that
exactly matches the sequence enabled at instance creation time are valid,
and validation layers should issue diagnostics for other cases.
Regardless of the enabled layer list provided in VkDeviceCreateInfo,
the sequence of layers active for a device will be exactly the sequence of
layers enabled when the parent instance was created.
31.2. Extensions
Extensions may define new Vulkan commands, structures, and enumerants.
For compilation purposes, the interfaces defined by registered extensions,
including new structures and enumerants as well as function pointer types
for new commands, are defined in the Khronos-supplied vulkan_core.h
together with the core API.
However, commands defined by extensions may not be available for static
linking - in which case function pointers to these commands should be
queried at runtime as described in Command Function Pointers.
Extensions may be provided by layers as well as by a Vulkan implementation.
Because extensions may extend or change the behavior of the Vulkan API, extension authors should add support for their extensions to the Khronos validation layers. This is especially important for new commands whose parameters have been wrapped by the validation layers. See the “Vulkan Loader Specification and Architecture Overview” document for additional information.
|
Note
Valid Usage sections for individual commands and structures do not currently contain which extensions have to be enabled in order to make their use valid, although it might do so in the future. It is defined only in the Valid Usage for Extensions section. |
To query the available instance extensions, call:
VkResult vkEnumerateInstanceExtensionProperties(
const char* pLayerName,
uint32_t* pPropertyCount,
VkExtensionProperties* pProperties);
-
pLayerNameis eitherNULLor a pointer to a null-terminated UTF-8 string naming the layer to retrieve extensions from. -
pPropertyCountis a pointer to an integer related to the number of extension properties available or queried, as described below. -
pPropertiesis eitherNULLor a pointer to an array of VkExtensionProperties structures.
When pLayerName parameter is NULL, only extensions provided by the
Vulkan implementation or by implicitly enabled layers are returned.
When pLayerName is the name of a layer, the instance extensions
provided by that layer are returned.
If pProperties is NULL, then the number of extensions properties
available is returned in pPropertyCount.
Otherwise, pPropertyCount must point to a variable set by the user to
the number of elements in the pProperties array, and on return the
variable is overwritten with the number of structures actually written to
pProperties.
If pPropertyCount is less than the number of extension properties
available, at most pPropertyCount structures will be written.
If pPropertyCount is smaller than the number of extensions available,
VK_INCOMPLETE will be returned instead of VK_SUCCESS, to
indicate that not all the available properties were returned.
Because the list of available layers may change externally between calls to
vkEnumerateInstanceExtensionProperties, two calls may retrieve
different results if a pLayerName is available in one call but not in
another.
The extensions supported by a layer may also change between two calls, e.g.
if the layer implementation is replaced by a different version between those
calls.
To enable an instance extension, the name of the extension should be added
to the ppEnabledExtensionNames member of VkInstanceCreateInfo
when creating a VkInstance.
Enabling an extension does not change behavior of functionality exposed by the core Vulkan API or any other extension, other than making valid the use of the commands, enums and structures defined by that extension.
To query the extensions available to a given physical device, call:
VkResult vkEnumerateDeviceExtensionProperties(
VkPhysicalDevice physicalDevice,
const char* pLayerName,
uint32_t* pPropertyCount,
VkExtensionProperties* pProperties);
-
physicalDeviceis the physical device that will be queried. -
pLayerNameis eitherNULLor a pointer to a null-terminated UTF-8 string naming the layer to retrieve extensions from. -
pPropertyCountis a pointer to an integer related to the number of extension properties available or queried, and is treated in the same fashion as the vkEnumerateInstanceExtensionProperties::pPropertyCountparameter. -
pPropertiesis eitherNULLor a pointer to an array of VkExtensionProperties structures.
When pLayerName parameter is NULL, only extensions provided by the
Vulkan implementation or by implicitly enabled layers are returned.
When pLayerName is the name of a layer, the device extensions provided
by that layer are returned.
The VkExtensionProperties structure is defined as:
typedef struct VkExtensionProperties {
char extensionName[VK_MAX_EXTENSION_NAME_SIZE];
uint32_t specVersion;
} VkExtensionProperties;
-
extensionNameis a null-terminated string specifying the name of the extension. -
specVersionis the version of this extension. It is an integer, incremented with backward compatible changes.
31.2.1. Instance Extensions and Device Extensions
This section provides some guidelines and rules for when to expose new functionality as an instance extension, as a device extension, or as both. The decision depends on the scope of the new functionality; such as whether it extends instance-level or device-level functionality. All Vulkan commands, structures, and enumerants are considered either instance-level, physical-device-level, or device-level.
New instance-level extension functionality must be structured within an
instance extension.
New device-level extension functionality may be structured within a device
extension.
Vulkan 1.0 initially required all new physical-device-level extension
functionality to be structured within an instance extension.
In order to avoid using an instance extension, which often requires loader
support, physical-device-level extension functionality may be implemented
within device extensions (which must depend on the
VK_KHR_get_physical_device_properties2 extension, or on Vulkan 1.1 or
later).
31.3. Extension Dependencies
Some extensions are dependent on other extensions to function. To enable extensions with dependencies, such required extensions must also be enabled through the same API mechanisms when creating an instance with vkCreateInstance or a device with vkCreateDevice. Each extension which has such dependencies documents them in the appendix summarizing that extension.
If an extension is supported (as queried by vkEnumerateInstanceExtensionProperties or vkEnumerateDeviceExtensionProperties), then required extensions of that extension must also be supported for the same instance or physical device.
Any device extension that has an instance extension dependency that is not enabled by vkCreateInstance is considered to be unsupported, hence it must not be returned by vkEnumerateDeviceExtensionProperties for any VkPhysicalDevice child of the instance.
31.4. Extension Compatibility
By default, all extensions are considered compatible with each other and any core API version, unless otherwise stated. Thus enabling such extensions does not otherwise alter the behavior of the application.
Each extension that is mutually exclusive or otherwise incompatible with
another extension or set of extensions documents them in the appendix summarizing that extension and has a corresponding Valid Usage
statement disallowing enabling such an incompatible combination of
extensions at VkInstance creation time or VkDevice creation
time, depending on the type of extensions participating in the interaction.
32. Features, Limits, and Formats
Vulkan is designed to support a wide variety of implementations, and as such there are a number of features, limits, and formats which are not supported on all implementations. Features describe functionality which is optional and which must be explicitly enabled before use. Limits describe implementation-dependent minimums, maximums, and other device characteristics that an application may need to be aware of. Supported buffer and image formats may vary across implementations. A minimum set of format features are guaranteed, but others must be explicitly queried before use to ensure they are supported by the implementation.
|
Note
The features and limits are reported via basic structures (that is
VkPhysicalDeviceFeatures and VkPhysicalDeviceLimits), as well as
extensible structures ( |
32.1. Features
The Specification defines a set of optional features that may be supported by a Vulkan implementation. Support for features is reported and enabled on a per-feature basis. Features are properties of the physical device.
To query supported features, call:
void vkGetPhysicalDeviceFeatures(
VkPhysicalDevice physicalDevice,
VkPhysicalDeviceFeatures* pFeatures);
-
physicalDeviceis the physical device from which to query the supported features. -
pFeaturesis a pointer to a VkPhysicalDeviceFeatures structure in which the physical device features are returned. For each feature, a value ofVK_TRUEspecifies that the feature is supported on this physical device, andVK_FALSEspecifies that the feature is not supported.
Fine-grained features used by a logical device must be enabled at
VkDevice creation time.
If a feature is enabled that the physical device does not support,
VkDevice creation will fail.
If an application uses a feature without enabling it at VkDevice
creation time, the device behavior is undefined.
The validation layer will warn if features are used without being enabled.
The fine-grained features are enabled by passing a pointer to the
VkPhysicalDeviceFeatures structure via the pEnabledFeatures
member of the VkDeviceCreateInfo structure that is passed into the
vkCreateDevice call.
If a member of pEnabledFeatures is set to VK_TRUE or
VK_FALSE, then the device will be created with the indicated feature
enabled or disabled, respectively.
Features can also be enabled by using the VkPhysicalDeviceFeatures2
structure.
If an application wishes to enable all features supported by a device, it
can simply pass in the VkPhysicalDeviceFeatures structure that was
previously returned by vkGetPhysicalDeviceFeatures.
To disable an individual feature, the application can set the desired
member to VK_FALSE in the same structure.
Setting pEnabledFeatures to NULL
and not including a VkPhysicalDeviceFeatures2 in the pNext
member of VkDeviceCreateInfo
is equivalent to setting all members of the structure to VK_FALSE.
|
Note
Some features, such as |
To query supported features defined by the core or extensions, call:
void vkGetPhysicalDeviceFeatures2(
VkPhysicalDevice physicalDevice,
VkPhysicalDeviceFeatures2* pFeatures);
or the equivalent command
void vkGetPhysicalDeviceFeatures2KHR(
VkPhysicalDevice physicalDevice,
VkPhysicalDeviceFeatures2* pFeatures);
-
physicalDeviceis the physical device from which to query the supported features. -
pFeaturesis a pointer to a VkPhysicalDeviceFeatures2 structure in which the physical device features are returned.
Each structure in pFeatures and its pNext chain contain members
corresponding to fine-grained features.
vkGetPhysicalDeviceFeatures2 writes each member to a boolean value
indicating whether that feature is supported.
The VkPhysicalDeviceFeatures2 structure is defined as:
typedef struct VkPhysicalDeviceFeatures2 {
VkStructureType sType;
void* pNext;
VkPhysicalDeviceFeatures features;
} VkPhysicalDeviceFeatures2;
or the equivalent
typedef VkPhysicalDeviceFeatures2 VkPhysicalDeviceFeatures2KHR;
The VkPhysicalDeviceFeatures2 structure is defined as:
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
featuresis a structure of type VkPhysicalDeviceFeatures describing the fine-grained features of the Vulkan 1.0 API.
The pNext chain of this structure is used to extend the structure with
features defined by extensions.
This structure can be used in vkGetPhysicalDeviceFeatures2 or can be
in the pNext chain of a VkDeviceCreateInfo structure, in which
case it controls which features are enabled in the device in lieu of
pEnabledFeatures.
The VkPhysicalDeviceFeatures structure is defined as:
typedef struct VkPhysicalDeviceFeatures {
VkBool32 robustBufferAccess;
VkBool32 fullDrawIndexUint32;
VkBool32 imageCubeArray;
VkBool32 independentBlend;
VkBool32 geometryShader;
VkBool32 tessellationShader;
VkBool32 sampleRateShading;
VkBool32 dualSrcBlend;
VkBool32 logicOp;
VkBool32 multiDrawIndirect;
VkBool32 drawIndirectFirstInstance;
VkBool32 depthClamp;
VkBool32 depthBiasClamp;
VkBool32 fillModeNonSolid;
VkBool32 depthBounds;
VkBool32 wideLines;
VkBool32 largePoints;
VkBool32 alphaToOne;
VkBool32 multiViewport;
VkBool32 samplerAnisotropy;
VkBool32 textureCompressionETC2;
VkBool32 textureCompressionASTC_LDR;
VkBool32 textureCompressionBC;
VkBool32 occlusionQueryPrecise;
VkBool32 pipelineStatisticsQuery;
VkBool32 vertexPipelineStoresAndAtomics;
VkBool32 fragmentStoresAndAtomics;
VkBool32 shaderTessellationAndGeometryPointSize;
VkBool32 shaderImageGatherExtended;
VkBool32 shaderStorageImageExtendedFormats;
VkBool32 shaderStorageImageMultisample;
VkBool32 shaderStorageImageReadWithoutFormat;
VkBool32 shaderStorageImageWriteWithoutFormat;
VkBool32 shaderUniformBufferArrayDynamicIndexing;
VkBool32 shaderSampledImageArrayDynamicIndexing;
VkBool32 shaderStorageBufferArrayDynamicIndexing;
VkBool32 shaderStorageImageArrayDynamicIndexing;
VkBool32 shaderClipDistance;
VkBool32 shaderCullDistance;
VkBool32 shaderFloat64;
VkBool32 shaderInt64;
VkBool32 shaderInt16;
VkBool32 shaderResourceResidency;
VkBool32 shaderResourceMinLod;
VkBool32 sparseBinding;
VkBool32 sparseResidencyBuffer;
VkBool32 sparseResidencyImage2D;
VkBool32 sparseResidencyImage3D;
VkBool32 sparseResidency2Samples;
VkBool32 sparseResidency4Samples;
VkBool32 sparseResidency8Samples;
VkBool32 sparseResidency16Samples;
VkBool32 sparseResidencyAliased;
VkBool32 variableMultisampleRate;
VkBool32 inheritedQueries;
} VkPhysicalDeviceFeatures;
The members of the VkPhysicalDeviceFeatures structure describe the
following features:
-
robustBufferAccessspecifies that accesses to buffers are bounds-checked against the range of the buffer descriptor (as determined byVkDescriptorBufferInfo::range,VkBufferViewCreateInfo::range, or the size of the buffer). Out of bounds accesses must not cause application termination, and the effects of shader loads, stores, and atomics must conform to an implementation-dependent behavior as described below.-
A buffer access is considered to be out of bounds if any of the following are true:
-
The pointer was formed by
OpImageTexelPointerand the coordinate is less than zero or greater than or equal to the number of whole elements in the bound range. -
The pointer was not formed by
OpImageTexelPointerand the object pointed to is not wholly contained within the bound range. This includes accesses performed via variable pointers where the buffer descriptor being accessed cannot be statically determined. Uninitialized pointers and pointers equal toOpConstantNullare treated as pointing to a zero-sized object, so all accesses through such pointers are considered to be out of bounds.NoteIf a SPIR-V
OpLoadinstruction loads a structure and the tail end of the structure is out of bounds, then all members of the structure are considered out of bounds even if the members at the end are not statically used. -
If any buffer access in a given SPIR-V block is determined to be out of bounds, then any other access of the same type (load, store, or atomic) in the same SPIR-V block that accesses an address less than 16 bytes away from the out of bounds address may also be considered out of bounds.
-
-
Out-of-bounds buffer loads will return any of the following values:
-
Values from anywhere within the memory range(s) bound to the buffer (possibly including bytes of memory past the end of the buffer, up to the end of the bound range).
-
Zero values, or (0,0,0,x) vectors for vector reads where x is a valid value represented in the type of the vector components and may be any of:
-
0, 1, or the maximum representable positive integer value, for signed or unsigned integer components
-
0.0 or 1.0, for floating-point components
-
-
-
Out-of-bounds writes may modify values within the memory range(s) bound to the buffer, but must not modify any other memory.
-
Out-of-bounds atomics may modify values within the memory range(s) bound to the buffer, but must not modify any other memory, and return an undefined value.
-
Vertex input attributes are considered out of bounds if the offset of the attribute in the bound vertex buffer range plus the size of the attribute is greater than either:
-
vertexBufferRangeSize, ifbindingStride== 0; or -
(
vertexBufferRangeSize- (vertexBufferRangeSize%bindingStride))
where
vertexBufferRangeSizeis the byte size of the memory range bound to the vertex buffer binding andbindingStrideis the byte stride of the corresponding vertex input binding. Further, if any vertex input attribute using a specific vertex input binding is out of bounds, then all vertex input attributes using that vertex input binding for that vertex shader invocation are considered out of bounds.-
If a vertex input attribute is out of bounds, it will be assigned one of the following values:
-
Values from anywhere within the memory range(s) bound to the buffer, converted according to the format of the attribute.
-
Zero values, format converted according to the format of the attribute.
-
Zero values, or (0,0,0,x) vectors, as described above.
-
-
-
If
robustBufferAccessis not enabled, out of bounds accesses may corrupt any memory within the process and cause undefined behavior up to and including application termination.
-
-
fullDrawIndexUint32specifies the full 32-bit range of indices is supported for indexed draw calls when using a VkIndexType ofVK_INDEX_TYPE_UINT32.maxDrawIndexedIndexValueis the maximum index value that may be used (aside from the primitive restart index, which is always 232-1 when the VkIndexType isVK_INDEX_TYPE_UINT32). If this feature is supported,maxDrawIndexedIndexValuemust be 232-1; otherwise it must be no smaller than 224-1. See maxDrawIndexedIndexValue. -
imageCubeArrayspecifies whether image views with a VkImageViewType ofVK_IMAGE_VIEW_TYPE_CUBE_ARRAYcan be created, and that the correspondingSampledCubeArrayandImageCubeArraySPIR-V capabilities can be used in shader code. -
independentBlendspecifies whether theVkPipelineColorBlendAttachmentStatesettings are controlled independently per-attachment. If this feature is not enabled, theVkPipelineColorBlendAttachmentStatesettings for all color attachments must be identical. Otherwise, a differentVkPipelineColorBlendAttachmentStatecan be provided for each bound color attachment. -
geometryShaderspecifies whether geometry shaders are supported. If this feature is not enabled, theVK_SHADER_STAGE_GEOMETRY_BITandVK_PIPELINE_STAGE_GEOMETRY_SHADER_BITenum values must not be used. This also specifies whether shader modules can declare theGeometrycapability. -
tessellationShaderspecifies whether tessellation control and evaluation shaders are supported. If this feature is not enabled, theVK_SHADER_STAGE_TESSELLATION_CONTROL_BIT,VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT,VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT,VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT, andVK_STRUCTURE_TYPE_PIPELINE_TESSELLATION_STATE_CREATE_INFOenum values must not be used. This also specifies whether shader modules can declare theTessellationcapability. -
sampleRateShadingspecifies whether Sample Shading and multisample interpolation are supported. If this feature is not enabled, thesampleShadingEnablemember of theVkPipelineMultisampleStateCreateInfostructure must be set toVK_FALSEand theminSampleShadingmember is ignored. This also specifies whether shader modules can declare theSampleRateShadingcapability. -
dualSrcBlendspecifies whether blend operations which take two sources are supported. If this feature is not enabled, theVK_BLEND_FACTOR_SRC1_COLOR,VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR,VK_BLEND_FACTOR_SRC1_ALPHA, andVK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHAenum values must not be used as source or destination blending factors. See Dual-Source Blending. -
logicOpspecifies whether logic operations are supported. If this feature is not enabled, thelogicOpEnablemember of theVkPipelineColorBlendStateCreateInfostructure must be set toVK_FALSE, and thelogicOpmember is ignored. -
multiDrawIndirectspecifies whether multiple draw indirect is supported. If this feature is not enabled, thedrawCountparameter to thevkCmdDrawIndirectandvkCmdDrawIndexedIndirectcommands must be 0 or 1. ThemaxDrawIndirectCountmember of theVkPhysicalDeviceLimitsstructure must also be 1 if this feature is not supported. See maxDrawIndirectCount. -
drawIndirectFirstInstancespecifies whether indirect draw calls support thefirstInstanceparameter. If this feature is not enabled, thefirstInstancemember of allVkDrawIndirectCommandandVkDrawIndexedIndirectCommandstructures that are provided to thevkCmdDrawIndirectandvkCmdDrawIndexedIndirectcommands must be 0. -
depthClampspecifies whether depth clamping is supported. If this feature is not enabled, thedepthClampEnablemember of theVkPipelineRasterizationStateCreateInfostructure must be set toVK_FALSE. Otherwise, settingdepthClampEnabletoVK_TRUEwill enable depth clamping. -
depthBiasClampspecifies whether depth bias clamping is supported. If this feature is not enabled, thedepthBiasClampmember of theVkPipelineRasterizationStateCreateInfostructure must be set to 0.0 unless theVK_DYNAMIC_STATE_DEPTH_BIASdynamic state is enabled, and thedepthBiasClampparameter tovkCmdSetDepthBiasmust be set to 0.0. -
fillModeNonSolidspecifies whether point and wireframe fill modes are supported. If this feature is not enabled, theVK_POLYGON_MODE_POINTandVK_POLYGON_MODE_LINEenum values must not be used. -
depthBoundsspecifies whether depth bounds tests are supported. If this feature is not enabled, thedepthBoundsTestEnablemember of theVkPipelineDepthStencilStateCreateInfostructure must be set toVK_FALSE. WhendepthBoundsTestEnableis set toVK_FALSE, theminDepthBoundsandmaxDepthBoundsmembers of theVkPipelineDepthStencilStateCreateInfostructure are ignored. -
wideLinesspecifies whether lines with width other than 1.0 are supported. If this feature is not enabled, thelineWidthmember of theVkPipelineRasterizationStateCreateInfostructure must be set to 1.0 unless theVK_DYNAMIC_STATE_LINE_WIDTHdynamic state is enabled, and thelineWidthparameter tovkCmdSetLineWidthmust be set to 1.0. When this feature is supported, the range and granularity of supported line widths are indicated by thelineWidthRangeandlineWidthGranularitymembers of theVkPhysicalDeviceLimitsstructure, respectively. -
largePointsspecifies whether points with size greater than 1.0 are supported. If this feature is not enabled, only a point size of 1.0 written by a shader is supported. The range and granularity of supported point sizes are indicated by thepointSizeRangeandpointSizeGranularitymembers of theVkPhysicalDeviceLimitsstructure, respectively. -
alphaToOnespecifies whether the implementation is able to replace the alpha value of the color fragment output from the fragment shader with the maximum representable alpha value for fixed-point colors or 1.0 for floating-point colors. If this feature is not enabled, then thealphaToOneEnablemember of theVkPipelineMultisampleStateCreateInfostructure must be set toVK_FALSE. Otherwise settingalphaToOneEnabletoVK_TRUEwill enable alpha-to-one behavior. -
multiViewportspecifies whether more than one viewport is supported. If this feature is not enabled, theviewportCountandscissorCountmembers of theVkPipelineViewportStateCreateInfostructure must be set to 1. Similarly, theviewportCountparameter to thevkCmdSetViewportcommand and thescissorCountparameter to thevkCmdSetScissorcommand must be 1, and thefirstViewportparameter to thevkCmdSetViewportcommand and thefirstScissorparameter to thevkCmdSetScissorcommand must be 0. -
samplerAnisotropyspecifies whether anisotropic filtering is supported. If this feature is not enabled, theanisotropyEnablemember of theVkSamplerCreateInfostructure must beVK_FALSE. -
textureCompressionETC2specifies whether all of the ETC2 and EAC compressed texture formats are supported. If this feature is enabled, then theVK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT,VK_FORMAT_FEATURE_BLIT_SRC_BITandVK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BITfeatures must be supported inoptimalTilingFeaturesfor the following formats:-
VK_FORMAT_ETC2_R8G8B8_UNORM_BLOCK -
VK_FORMAT_ETC2_R8G8B8_SRGB_BLOCK -
VK_FORMAT_ETC2_R8G8B8A1_UNORM_BLOCK -
VK_FORMAT_ETC2_R8G8B8A1_SRGB_BLOCK -
VK_FORMAT_ETC2_R8G8B8A8_UNORM_BLOCK -
VK_FORMAT_ETC2_R8G8B8A8_SRGB_BLOCK -
VK_FORMAT_EAC_R11_UNORM_BLOCK -
VK_FORMAT_EAC_R11_SNORM_BLOCK -
VK_FORMAT_EAC_R11G11_UNORM_BLOCK -
VK_FORMAT_EAC_R11G11_SNORM_BLOCK
vkGetPhysicalDeviceFormatProperties and vkGetPhysicalDeviceImageFormatProperties can be used to check for additional supported properties of individual formats.
-
-
textureCompressionASTC_LDRspecifies whether all of the ASTC LDR compressed texture formats are supported. If this feature is enabled, then theVK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT,VK_FORMAT_FEATURE_BLIT_SRC_BITandVK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BITfeatures must be supported inoptimalTilingFeaturesfor the following formats:-
VK_FORMAT_ASTC_4x4_UNORM_BLOCK -
VK_FORMAT_ASTC_4x4_SRGB_BLOCK -
VK_FORMAT_ASTC_5x4_UNORM_BLOCK -
VK_FORMAT_ASTC_5x4_SRGB_BLOCK -
VK_FORMAT_ASTC_5x5_UNORM_BLOCK -
VK_FORMAT_ASTC_5x5_SRGB_BLOCK -
VK_FORMAT_ASTC_6x5_UNORM_BLOCK -
VK_FORMAT_ASTC_6x5_SRGB_BLOCK -
VK_FORMAT_ASTC_6x6_UNORM_BLOCK -
VK_FORMAT_ASTC_6x6_SRGB_BLOCK -
VK_FORMAT_ASTC_8x5_UNORM_BLOCK -
VK_FORMAT_ASTC_8x5_SRGB_BLOCK -
VK_FORMAT_ASTC_8x6_UNORM_BLOCK -
VK_FORMAT_ASTC_8x6_SRGB_BLOCK -
VK_FORMAT_ASTC_8x8_UNORM_BLOCK -
VK_FORMAT_ASTC_8x8_SRGB_BLOCK -
VK_FORMAT_ASTC_10x5_UNORM_BLOCK -
VK_FORMAT_ASTC_10x5_SRGB_BLOCK -
VK_FORMAT_ASTC_10x6_UNORM_BLOCK -
VK_FORMAT_ASTC_10x6_SRGB_BLOCK -
VK_FORMAT_ASTC_10x8_UNORM_BLOCK -
VK_FORMAT_ASTC_10x8_SRGB_BLOCK -
VK_FORMAT_ASTC_10x10_UNORM_BLOCK -
VK_FORMAT_ASTC_10x10_SRGB_BLOCK -
VK_FORMAT_ASTC_12x10_UNORM_BLOCK -
VK_FORMAT_ASTC_12x10_SRGB_BLOCK -
VK_FORMAT_ASTC_12x12_UNORM_BLOCK -
VK_FORMAT_ASTC_12x12_SRGB_BLOCK
vkGetPhysicalDeviceFormatProperties and vkGetPhysicalDeviceImageFormatProperties can be used to check for additional supported properties of individual formats.
-
-
textureCompressionBCspecifies whether all of the BC compressed texture formats are supported. If this feature is enabled, then theVK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT,VK_FORMAT_FEATURE_BLIT_SRC_BITandVK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BITfeatures must be supported inoptimalTilingFeaturesfor the following formats:-
VK_FORMAT_BC1_RGB_UNORM_BLOCK -
VK_FORMAT_BC1_RGB_SRGB_BLOCK -
VK_FORMAT_BC1_RGBA_UNORM_BLOCK -
VK_FORMAT_BC1_RGBA_SRGB_BLOCK -
VK_FORMAT_BC2_UNORM_BLOCK -
VK_FORMAT_BC2_SRGB_BLOCK -
VK_FORMAT_BC3_UNORM_BLOCK -
VK_FORMAT_BC3_SRGB_BLOCK -
VK_FORMAT_BC4_UNORM_BLOCK -
VK_FORMAT_BC4_SNORM_BLOCK -
VK_FORMAT_BC5_UNORM_BLOCK -
VK_FORMAT_BC5_SNORM_BLOCK -
VK_FORMAT_BC6H_UFLOAT_BLOCK -
VK_FORMAT_BC6H_SFLOAT_BLOCK -
VK_FORMAT_BC7_UNORM_BLOCK -
VK_FORMAT_BC7_SRGB_BLOCK
vkGetPhysicalDeviceFormatProperties and vkGetPhysicalDeviceImageFormatProperties can be used to check for additional supported properties of individual formats.
-
-
occlusionQueryPrecisespecifies whether occlusion queries returning actual sample counts are supported. Occlusion queries are created in aVkQueryPoolby specifying thequeryTypeofVK_QUERY_TYPE_OCCLUSIONin theVkQueryPoolCreateInfostructure which is passed tovkCreateQueryPool. If this feature is enabled, queries of this type can enableVK_QUERY_CONTROL_PRECISE_BITin theflagsparameter tovkCmdBeginQuery. If this feature is not supported, the implementation supports only boolean occlusion queries. When any samples are passed, boolean queries will return a non-zero result value, otherwise a result value of zero is returned. When this feature is enabled andVK_QUERY_CONTROL_PRECISE_BITis set, occlusion queries will report the actual number of samples passed. -
pipelineStatisticsQueryspecifies whether the pipeline statistics queries are supported. If this feature is not enabled, queries of typeVK_QUERY_TYPE_PIPELINE_STATISTICScannot be created, and none of the VkQueryPipelineStatisticFlagBits bits can be set in thepipelineStatisticsmember of theVkQueryPoolCreateInfostructure. -
vertexPipelineStoresAndAtomicsspecifies whether storage buffers and images support stores and atomic operations in the vertex, tessellation, and geometry shader stages. If this feature is not enabled, all storage image, storage texel buffers, and storage buffer variables used by these stages in shader modules must be decorated with theNonWriteabledecoration (or thereadonlymemory qualifier in GLSL). -
fragmentStoresAndAtomicsspecifies whether storage buffers and images support stores and atomic operations in the fragment shader stage. If this feature is not enabled, all storage image, storage texel buffers, and storage buffer variables used by the fragment stage in shader modules must be decorated with theNonWriteabledecoration (or thereadonlymemory qualifier in GLSL). -
shaderTessellationAndGeometryPointSizespecifies whether thePointSizebuilt-in decoration is available in the tessellation control, tessellation evaluation, and geometry shader stages. If this feature is not enabled, members decorated with thePointSizebuilt-in decoration must not be read from or written to and all points written from a tessellation or geometry shader will have a size of 1.0. This also specifies whether shader modules can declare theTessellationPointSizecapability for tessellation control and evaluation shaders, or if the shader modules can declare theGeometryPointSizecapability for geometry shaders. An implementation supporting this feature must also support one or both of thetessellationShaderorgeometryShaderfeatures. -
shaderImageGatherExtendedspecifies whether the extended set of image gather instructions are available in shader code. If this feature is not enabled, theOpImage*Gatherinstructions do not support theOffsetandConstOffsetsoperands. This also specifies whether shader modules can declare theImageGatherExtendedcapability. -
shaderStorageImageExtendedFormatsspecifies whether the extended storage image formats are available in shader code. If this feature is not enabled, the formats requiring theStorageImageExtendedFormatscapability are not supported for storage images. This also specifies whether shader modules can declare theStorageImageExtendedFormatscapability. -
shaderStorageImageMultisamplespecifies whether multisampled storage images are supported. If this feature is not enabled, images that are created with ausagethat includesVK_IMAGE_USAGE_STORAGE_BITmust be created withsamplesequal toVK_SAMPLE_COUNT_1_BIT. This also specifies whether shader modules can declare theStorageImageMultisamplecapability. -
shaderStorageImageReadWithoutFormatspecifies whether storage images require a format qualifier to be specified when reading from storage images. If this feature is not enabled, theOpImageReadinstruction must not have anOpTypeImageofUnknown. This also specifies whether shader modules can declare theStorageImageReadWithoutFormatcapability. -
shaderStorageImageWriteWithoutFormatspecifies whether storage images require a format qualifier to be specified when writing to storage images. If this feature is not enabled, theOpImageWriteinstruction must not have anOpTypeImageofUnknown. This also specifies whether shader modules can declare theStorageImageWriteWithoutFormatcapability. -
shaderUniformBufferArrayDynamicIndexingspecifies whether arrays of uniform buffers can be indexed by dynamically uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type ofVK_DESCRIPTOR_TYPE_UNIFORM_BUFFERorVK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMICmust be indexed only by constant integral expressions when aggregated into arrays in shader code. This also specifies whether shader modules can declare theUniformBufferArrayDynamicIndexingcapability. -
shaderSampledImageArrayDynamicIndexingspecifies whether arrays of samplers or sampled images can be indexed by dynamically uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type ofVK_DESCRIPTOR_TYPE_SAMPLER,VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, orVK_DESCRIPTOR_TYPE_SAMPLED_IMAGEmust be indexed only by constant integral expressions when aggregated into arrays in shader code. This also specifies whether shader modules can declare theSampledImageArrayDynamicIndexingcapability. -
shaderStorageBufferArrayDynamicIndexingspecifies whether arrays of storage buffers can be indexed by dynamically uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type ofVK_DESCRIPTOR_TYPE_STORAGE_BUFFERorVK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMICmust be indexed only by constant integral expressions when aggregated into arrays in shader code. This also specifies whether shader modules can declare theStorageBufferArrayDynamicIndexingcapability. -
shaderStorageImageArrayDynamicIndexingspecifies whether arrays of storage images can be indexed by dynamically uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type ofVK_DESCRIPTOR_TYPE_STORAGE_IMAGEmust be indexed only by constant integral expressions when aggregated into arrays in shader code. This also specifies whether shader modules can declare theStorageImageArrayDynamicIndexingcapability. -
shaderClipDistancespecifies whether clip distances are supported in shader code. If this feature is not enabled, any members decorated with theClipDistancebuilt-in decoration must not be read from or written to in shader modules. This also specifies whether shader modules can declare theClipDistancecapability. -
shaderCullDistancespecifies whether cull distances are supported in shader code. If this feature is not enabled, any members decorated with theCullDistancebuilt-in decoration must not be read from or written to in shader modules. This also specifies whether shader modules can declare theCullDistancecapability. -
shaderFloat64specifies whether 64-bit floats (doubles) are supported in shader code. If this feature is not enabled, 64-bit floating-point types must not be used in shader code. This also specifies whether shader modules can declare theFloat64capability. -
shaderInt64specifies whether 64-bit integers (signed and unsigned) are supported in shader code. If this feature is not enabled, 64-bit integer types must not be used in shader code. This also specifies whether shader modules can declare theInt64capability. -
shaderInt16specifies whether 16-bit integers (signed and unsigned) are supported in shader code. If this feature is not enabled, 16-bit integer types must not be used in shader code. This also specifies whether shader modules can declare theInt16capability. -
shaderResourceResidencyspecifies whether image operations that return resource residency information are supported in shader code. If this feature is not enabled, theOpImageSparse* instructions must not be used in shader code. This also specifies whether shader modules can declare theSparseResidencycapability. The feature requires at least one of thesparseResidency*features to be supported. -
shaderResourceMinLodspecifies whether image operations that specify the minimum resource LOD are supported in shader code. If this feature is not enabled, theMinLodimage operand must not be used in shader code. This also specifies whether shader modules can declare theMinLodcapability. -
sparseBindingspecifies whether resource memory can be managed at opaque sparse block level instead of at the object level. If this feature is not enabled, resource memory must be bound only on a per-object basis using thevkBindBufferMemoryandvkBindImageMemorycommands. In this case, buffers and images must not be created withVK_BUFFER_CREATE_SPARSE_BINDING_BITandVK_IMAGE_CREATE_SPARSE_BINDING_BITset in theflagsmember of theVkBufferCreateInfoandVkImageCreateInfostructures, respectively. Otherwise resource memory can be managed as described in Sparse Resource Features. -
sparseResidencyBufferspecifies whether the device can access partially resident buffers. If this feature is not enabled, buffers must not be created withVK_BUFFER_CREATE_SPARSE_RESIDENCY_BITset in theflagsmember of theVkBufferCreateInfostructure. -
sparseResidencyImage2Dspecifies whether the device can access partially resident 2D images with 1 sample per pixel. If this feature is not enabled, images with animageTypeofVK_IMAGE_TYPE_2Dandsamplesset toVK_SAMPLE_COUNT_1_BITmust not be created withVK_IMAGE_CREATE_SPARSE_RESIDENCY_BITset in theflagsmember of theVkImageCreateInfostructure. -
sparseResidencyImage3Dspecifies whether the device can access partially resident 3D images. If this feature is not enabled, images with animageTypeofVK_IMAGE_TYPE_3Dmust not be created withVK_IMAGE_CREATE_SPARSE_RESIDENCY_BITset in theflagsmember of theVkImageCreateInfostructure. -
sparseResidency2Samplesspecifies whether the physical device can access partially resident 2D images with 2 samples per pixel. If this feature is not enabled, images with animageTypeofVK_IMAGE_TYPE_2Dandsamplesset toVK_SAMPLE_COUNT_2_BITmust not be created withVK_IMAGE_CREATE_SPARSE_RESIDENCY_BITset in theflagsmember of theVkImageCreateInfostructure. -
sparseResidency4Samplesspecifies whether the physical device can access partially resident 2D images with 4 samples per pixel. If this feature is not enabled, images with animageTypeofVK_IMAGE_TYPE_2Dandsamplesset toVK_SAMPLE_COUNT_4_BITmust not be created withVK_IMAGE_CREATE_SPARSE_RESIDENCY_BITset in theflagsmember of theVkImageCreateInfostructure. -
sparseResidency8Samplesspecifies whether the physical device can access partially resident 2D images with 8 samples per pixel. If this feature is not enabled, images with animageTypeofVK_IMAGE_TYPE_2Dandsamplesset toVK_SAMPLE_COUNT_8_BITmust not be created withVK_IMAGE_CREATE_SPARSE_RESIDENCY_BITset in theflagsmember of theVkImageCreateInfostructure. -
sparseResidency16Samplesspecifies whether the physical device can access partially resident 2D images with 16 samples per pixel. If this feature is not enabled, images with animageTypeofVK_IMAGE_TYPE_2Dandsamplesset toVK_SAMPLE_COUNT_16_BITmust not be created withVK_IMAGE_CREATE_SPARSE_RESIDENCY_BITset in theflagsmember of theVkImageCreateInfostructure. -
sparseResidencyAliasedspecifies whether the physical device can correctly access data aliased into multiple locations. If this feature is not enabled, theVK_BUFFER_CREATE_SPARSE_ALIASED_BITandVK_IMAGE_CREATE_SPARSE_ALIASED_BITenum values must not be used inflagsmembers of theVkBufferCreateInfoandVkImageCreateInfostructures, respectively. -
variableMultisampleRatespecifies whether all pipelines that will be bound to a command buffer during a subpass with no attachments must have the same value forVkPipelineMultisampleStateCreateInfo::rasterizationSamples. If set toVK_TRUE, the implementation supports variable multisample rates in a subpass with no attachments. If set toVK_FALSE, then all pipelines bound in such a subpass must have the same multisample rate. This has no effect in situations where a subpass uses any attachments. -
inheritedQueriesspecifies whether a secondary command buffer may be executed while a query is active.
The VkPhysicalDeviceVariablePointerFeatures structure is defined as:
typedef struct VkPhysicalDeviceVariablePointerFeatures {
VkStructureType sType;
void* pNext;
VkBool32 variablePointersStorageBuffer;
VkBool32 variablePointers;
} VkPhysicalDeviceVariablePointerFeatures;
or the equivalent
typedef VkPhysicalDeviceVariablePointerFeatures VkPhysicalDeviceVariablePointerFeaturesKHR;
The members of the VkPhysicalDeviceVariablePointerFeatures structure
describe the following features:
-
variablePointersStorageBufferspecifies whether the implementation supports the SPIR-VVariablePointersStorageBuffercapability. When this feature is not enabled, shader modules must not declare theSPV_KHR_variable_pointersextension or theVariablePointersStorageBuffercapability. -
variablePointersspecifies whether the implementation supports the SPIR-VVariablePointerscapability. When this feature is not enabled, shader modules must not declare theVariablePointerscapability.
If the VkPhysicalDeviceVariablePointerFeatures structure is included
in the pNext chain of VkPhysicalDeviceFeatures2, it is filled
with values indicating whether each feature is supported.
VkPhysicalDeviceVariablePointerFeatures can also be used in the
pNext chain of VkDeviceCreateInfo to enable the features.
The VkPhysicalDeviceMultiviewFeatures structure is defined as:
typedef struct VkPhysicalDeviceMultiviewFeatures {
VkStructureType sType;
void* pNext;
VkBool32 multiview;
VkBool32 multiviewGeometryShader;
VkBool32 multiviewTessellationShader;
} VkPhysicalDeviceMultiviewFeatures;
or the equivalent
typedef VkPhysicalDeviceMultiviewFeatures VkPhysicalDeviceMultiviewFeaturesKHR;
The members of the VkPhysicalDeviceMultiviewFeatures structure
describe the following features:
-
multiviewspecifies whether the implementation supports multiview rendering within a render pass. If this feature is not enabled, the view mask of each subpass must always be zero. -
multiviewGeometryShaderspecifies whether the implementation supports multiview rendering within a render pass, with geometry shaders. If this feature is not enabled, then a pipeline compiled against a subpass with a non-zero view mask must not include a geometry shader. -
multiviewTessellationShaderspecifies whether the implementation supports multiview rendering within a render pass, with tessellation shaders. If this feature is not enabled, then a pipeline compiled against a subpass with a non-zero view mask must not include any tessellation shaders.
If the VkPhysicalDeviceMultiviewFeatures structure is included in the
pNext chain of VkPhysicalDeviceFeatures2, it is filled with
values indicating whether each feature is supported.
VkPhysicalDeviceMultiviewFeatures can also be used in the pNext
chain of VkDeviceCreateInfo to enable the features.
To query 16-bit storage features additionally supported call
vkGetPhysicalDeviceFeatures2 with a
VkPhysicalDevice16BitStorageFeatures structure included in the
pNext chain of its pFeatures parameter.
The VkPhysicalDevice16BitStorageFeatures structure can also be in the
pNext chain of a VkDeviceCreateInfo structure, in which case it
controls which additional features are enabled in the device.
The VkPhysicalDevice16BitStorageFeatures structure is defined as:
typedef struct VkPhysicalDevice16BitStorageFeatures {
VkStructureType sType;
void* pNext;
VkBool32 storageBuffer16BitAccess;
VkBool32 uniformAndStorageBuffer16BitAccess;
VkBool32 storagePushConstant16;
VkBool32 storageInputOutput16;
} VkPhysicalDevice16BitStorageFeatures;
or the equivalent
typedef VkPhysicalDevice16BitStorageFeatures VkPhysicalDevice16BitStorageFeaturesKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
storageBuffer16BitAccessspecifies whether objects in theStorageBufferstorage class with theBlockdecoration can have 16-bit integer and 16-bit floating-point members. If this feature is not enabled, 16-bit integer or 16-bit floating-point members must not be used in such objects. This also specifies whether shader modules can declare theStorageBuffer16BitAccesscapability. -
uniformAndStorageBuffer16BitAccessspecifies whether objects in theUniformstorage class with theBlockdecoration and in theStorageBufferstorage class with the same decoration can have 16-bit integer and 16-bit floating-point members. If this feature is not enabled, 16-bit integer or 16-bit floating-point members must not be used in such objects. This also specifies whether shader modules can declare theUniformAndStorageBuffer16BitAccesscapability. -
storagePushConstant16specifies whether objects in thePushConstantstorage class can have 16-bit integer and 16-bit floating-point members. If this feature is not enabled, 16-bit integer or floating-point members must not be used in such objects. This also specifies whether shader modules can declare theStoragePushConstant16capability. -
storageInputOutput16specifies whether objects in theInputandOutputstorage classes can have 16-bit integer and 16-bit floating-point members. If this feature is not enabled, 16-bit integer or 16-bit floating-point members must not be used in such objects. This also specifies whether shader modules can declare theStorageInputOutput16capability.
The VkPhysicalDeviceSamplerYcbcrConversionFeatures structure is
defined as:
typedef struct VkPhysicalDeviceSamplerYcbcrConversionFeatures {
VkStructureType sType;
void* pNext;
VkBool32 samplerYcbcrConversion;
} VkPhysicalDeviceSamplerYcbcrConversionFeatures;
or the equivalent
typedef VkPhysicalDeviceSamplerYcbcrConversionFeatures VkPhysicalDeviceSamplerYcbcrConversionFeaturesKHR;
The members of the VkPhysicalDeviceSamplerYcbcrConversionFeatures
structure describe the following feature:
-
samplerYcbcrConversionspecifies whether the implementation supports sampler Y’CBCR conversion. IfsamplerYcbcrConversionisVK_FALSE, sampler Y’CBCR conversion is not supported, and samplers using sampler Y’CBCR conversion must not be used.
The VkPhysicalDeviceProtectedMemoryFeatures structure is defined as:
typedef struct VkPhysicalDeviceProtectedMemoryFeatures {
VkStructureType sType;
void* pNext;
VkBool32 protectedMemory;
} VkPhysicalDeviceProtectedMemoryFeatures;
-
protectedMemoryspecifies whether protected memory is supported.
If the VkPhysicalDeviceProtectedMemoryFeatures structure is included
in the pNext chain of VkPhysicalDeviceFeatures2, it is filled
with a value indicating whether the feature is supported.
The VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT structure is
defined as:
typedef struct VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT {
VkStructureType sType;
void* pNext;
VkBool32 advancedBlendCoherentOperations;
} VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT;
The members of the VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT
structure describe the following features:
-
advancedBlendCoherentOperationsspecifies whether blending using advanced blend operations is guaranteed to execute atomically and in primitive order. If this isVK_TRUE,VK_ACCESS_COLOR_ATTACHMENT_READ_NONCOHERENT_BIT_EXTis treated the same asVK_ACCESS_COLOR_ATTACHMENT_READ_BIT, and advanced blending needs no additional synchronization over basic blending. If this isVK_FALSE, then memory dependencies are required to guarantee order between two advanced blending operations that occur on the same sample.
If the VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT structure is
included in the pNext chain of VkPhysicalDeviceFeatures2, it is
filled with values indicating whether each feature is supported.
VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT can also be used in
pNext chain of VkDeviceCreateInfo to enable the features.
The VkPhysicalDeviceShaderDrawParameterFeatures structure is defined
as:
typedef struct VkPhysicalDeviceShaderDrawParameterFeatures {
VkStructureType sType;
void* pNext;
VkBool32 shaderDrawParameters;
} VkPhysicalDeviceShaderDrawParameterFeatures;
If the VkPhysicalDeviceShaderDrawParameterFeatures structure is
included in the pNext chain of VkPhysicalDeviceFeatures2, it is
filled with a value indicating whether the feature is supported.
The VkPhysicalDeviceDescriptorIndexingFeaturesEXT structure is defined
as:
typedef struct VkPhysicalDeviceDescriptorIndexingFeaturesEXT {
VkStructureType sType;
void* pNext;
VkBool32 shaderInputAttachmentArrayDynamicIndexing;
VkBool32 shaderUniformTexelBufferArrayDynamicIndexing;
VkBool32 shaderStorageTexelBufferArrayDynamicIndexing;
VkBool32 shaderUniformBufferArrayNonUniformIndexing;
VkBool32 shaderSampledImageArrayNonUniformIndexing;
VkBool32 shaderStorageBufferArrayNonUniformIndexing;
VkBool32 shaderStorageImageArrayNonUniformIndexing;
VkBool32 shaderInputAttachmentArrayNonUniformIndexing;
VkBool32 shaderUniformTexelBufferArrayNonUniformIndexing;
VkBool32 shaderStorageTexelBufferArrayNonUniformIndexing;
VkBool32 descriptorBindingUniformBufferUpdateAfterBind;
VkBool32 descriptorBindingSampledImageUpdateAfterBind;
VkBool32 descriptorBindingStorageImageUpdateAfterBind;
VkBool32 descriptorBindingStorageBufferUpdateAfterBind;
VkBool32 descriptorBindingUniformTexelBufferUpdateAfterBind;
VkBool32 descriptorBindingStorageTexelBufferUpdateAfterBind;
VkBool32 descriptorBindingUpdateUnusedWhilePending;
VkBool32 descriptorBindingPartiallyBound;
VkBool32 descriptorBindingVariableDescriptorCount;
VkBool32 runtimeDescriptorArray;
} VkPhysicalDeviceDescriptorIndexingFeaturesEXT;
The members of the VkPhysicalDeviceDescriptorIndexingFeaturesEXT
structure describe the following features:
-
shaderInputAttachmentArrayDynamicIndexingindicates whether arrays of input attachments can be indexed by dynamically uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type ofVK_DESCRIPTOR_TYPE_INPUT_ATTACHMENTmust be indexed only by constant integral expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare theInputAttachmentArrayDynamicIndexingEXTcapability. -
shaderUniformTexelBufferArrayDynamicIndexingindicates whether arrays of uniform texel buffers can be indexed by dynamically uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type ofVK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFERmust be indexed only by constant integral expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare theUniformTexelBufferArrayDynamicIndexingEXTcapability. -
shaderStorageTexelBufferArrayDynamicIndexingindicates whether arrays of storage texel buffers can be indexed by dynamically uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type ofVK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFERmust be indexed only by constant integral expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare theStorageTexelBufferArrayDynamicIndexingEXTcapability. -
shaderUniformBufferArrayNonUniformIndexingindicates whether arrays of uniform buffers can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type ofVK_DESCRIPTOR_TYPE_UNIFORM_BUFFERorVK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMICmust not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare theUniformBufferArrayNonUniformIndexingEXTcapability. -
shaderSampledImageArrayNonUniformIndexingindicates whether arrays of samplers or sampled images can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type ofVK_DESCRIPTOR_TYPE_SAMPLER,VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, orVK_DESCRIPTOR_TYPE_SAMPLED_IMAGEmust not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare theSampledImageArrayNonUniformIndexingEXTcapability. -
shaderStorageBufferArrayNonUniformIndexingindicates whether arrays of storage buffers can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type ofVK_DESCRIPTOR_TYPE_STORAGE_BUFFERorVK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMICmust not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare theStorageBufferArrayNonUniformIndexingEXTcapability. -
shaderStorageImageArrayNonUniformIndexingindicates whether arrays of storage images can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type ofVK_DESCRIPTOR_TYPE_STORAGE_IMAGEmust not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare theStorageImageArrayNonUniformIndexingEXTcapability. -
shaderInputAttachmentArrayNonUniformIndexingindicates whether arrays of input attachments can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type ofVK_DESCRIPTOR_TYPE_INPUT_ATTACHMENTmust not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare theInputAttachmentArrayNonUniformIndexingEXTcapability. -
shaderUniformTexelBufferArrayNonUniformIndexingindicates whether arrays of uniform texel buffers can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type ofVK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFERmust not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare theUniformTexelBufferArrayNonUniformIndexingEXTcapability. -
shaderStorageTexelBufferArrayNonUniformIndexingindicates whether arrays of storage texel buffers can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type ofVK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFERmust not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare theStorageTexelBufferArrayNonUniformIndexingEXTcapability. -
descriptorBindingUniformBufferUpdateAfterBindindicates whether the implementation supports updating uniform buffer descriptors after a set is bound. If this feature is not enabled,VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT_EXTmust not be used withVK_DESCRIPTOR_TYPE_UNIFORM_BUFFER. -
descriptorBindingSampledImageUpdateAfterBindindicates whether the implementation supports updating sampled image descriptors after a set is bound. If this feature is not enabled,VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT_EXTmust not be used withVK_DESCRIPTOR_TYPE_SAMPLER,VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, orVK_DESCRIPTOR_TYPE_SAMPLED_IMAGE. -
descriptorBindingStorageImageUpdateAfterBindindicates whether the implementation supports updating storage image descriptors after a set is bound. If this feature is not enabled,VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT_EXTmust not be used withVK_DESCRIPTOR_TYPE_STORAGE_IMAGE. -
descriptorBindingStorageBufferUpdateAfterBindindicates whether the implementation supports updating storage buffer descriptors after a set is bound. If this feature is not enabled,VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT_EXTmust not be used withVK_DESCRIPTOR_TYPE_STORAGE_BUFFER. -
descriptorBindingUniformTexelBufferUpdateAfterBindindicates whether the implementation supports updating uniform texel buffer descriptors after a set is bound. If this feature is not enabled,VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT_EXTmust not be used withVK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER. -
descriptorBindingStorageTexelBufferUpdateAfterBindindicates whether the implementation supports updating storage texel buffer descriptors after a set is bound. If this feature is not enabled,VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT_EXTmust not be used withVK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER. -
descriptorBindingUpdateUnusedWhilePendingindicates whether the implementation supports updating descriptors while the set is in use. If this feature is not enabled,VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT_EXTmust not be used. -
descriptorBindingPartiallyBoundindicates whether the implementation supports statically using a descriptor set binding in which some descriptors are not valid. If this feature is not enabled,VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT_EXTmust not be used. -
descriptorBindingVariableDescriptorCountindicates whether the implementation supports descriptor sets with a variable-sized last binding. If this feature is not enabled,VK_DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT_EXTmust not be used. -
runtimeDescriptorArrayindicates whether the implementation supports the SPIR-V RuntimeDescriptorArrayEXT capability. If this feature is not enabled, descriptors must not be declared in runtime arrays.
If the VkPhysicalDeviceDescriptorIndexingFeaturesEXT structure is
included in the pNext chain of VkPhysicalDeviceFeatures2KHR, it
is filled with values indicating whether each feature is supported.
VkPhysicalDeviceDescriptorIndexingFeaturesEXT can also be used in the
pNext chain of VkDeviceCreateInfo to enable features.
32.1.1. Feature Requirements
All Vulkan graphics implementations must support the following features:
-
variablePointersStorageBuffer, if theVK_KHR_variable_pointersextension is supported. -
If the
VK_EXT_descriptor_indexingextension is supported:
All other features defined in the Specification are optional.
32.2. Limits
There are a variety of implementation-dependent limits.
The VkPhysicalDeviceLimits are properties of the physical device.
These are available in the limits member of the
VkPhysicalDeviceProperties structure which is returned from
vkGetPhysicalDeviceProperties.
The VkPhysicalDeviceLimits structure is defined as:
typedef struct VkPhysicalDeviceLimits {
uint32_t maxImageDimension1D;
uint32_t maxImageDimension2D;
uint32_t maxImageDimension3D;
uint32_t maxImageDimensionCube;
uint32_t maxImageArrayLayers;
uint32_t maxTexelBufferElements;
uint32_t maxUniformBufferRange;
uint32_t maxStorageBufferRange;
uint32_t maxPushConstantsSize;
uint32_t maxMemoryAllocationCount;
uint32_t maxSamplerAllocationCount;
VkDeviceSize bufferImageGranularity;
VkDeviceSize sparseAddressSpaceSize;
uint32_t maxBoundDescriptorSets;
uint32_t maxPerStageDescriptorSamplers;
uint32_t maxPerStageDescriptorUniformBuffers;
uint32_t maxPerStageDescriptorStorageBuffers;
uint32_t maxPerStageDescriptorSampledImages;
uint32_t maxPerStageDescriptorStorageImages;
uint32_t maxPerStageDescriptorInputAttachments;
uint32_t maxPerStageResources;
uint32_t maxDescriptorSetSamplers;
uint32_t maxDescriptorSetUniformBuffers;
uint32_t maxDescriptorSetUniformBuffersDynamic;
uint32_t maxDescriptorSetStorageBuffers;
uint32_t maxDescriptorSetStorageBuffersDynamic;
uint32_t maxDescriptorSetSampledImages;
uint32_t maxDescriptorSetStorageImages;
uint32_t maxDescriptorSetInputAttachments;
uint32_t maxVertexInputAttributes;
uint32_t maxVertexInputBindings;
uint32_t maxVertexInputAttributeOffset;
uint32_t maxVertexInputBindingStride;
uint32_t maxVertexOutputComponents;
uint32_t maxTessellationGenerationLevel;
uint32_t maxTessellationPatchSize;
uint32_t maxTessellationControlPerVertexInputComponents;
uint32_t maxTessellationControlPerVertexOutputComponents;
uint32_t maxTessellationControlPerPatchOutputComponents;
uint32_t maxTessellationControlTotalOutputComponents;
uint32_t maxTessellationEvaluationInputComponents;
uint32_t maxTessellationEvaluationOutputComponents;
uint32_t maxGeometryShaderInvocations;
uint32_t maxGeometryInputComponents;
uint32_t maxGeometryOutputComponents;
uint32_t maxGeometryOutputVertices;
uint32_t maxGeometryTotalOutputComponents;
uint32_t maxFragmentInputComponents;
uint32_t maxFragmentOutputAttachments;
uint32_t maxFragmentDualSrcAttachments;
uint32_t maxFragmentCombinedOutputResources;
uint32_t maxComputeSharedMemorySize;
uint32_t maxComputeWorkGroupCount[3];
uint32_t maxComputeWorkGroupInvocations;
uint32_t maxComputeWorkGroupSize[3];
uint32_t subPixelPrecisionBits;
uint32_t subTexelPrecisionBits;
uint32_t mipmapPrecisionBits;
uint32_t maxDrawIndexedIndexValue;
uint32_t maxDrawIndirectCount;
float maxSamplerLodBias;
float maxSamplerAnisotropy;
uint32_t maxViewports;
uint32_t maxViewportDimensions[2];
float viewportBoundsRange[2];
uint32_t viewportSubPixelBits;
size_t minMemoryMapAlignment;
VkDeviceSize minTexelBufferOffsetAlignment;
VkDeviceSize minUniformBufferOffsetAlignment;
VkDeviceSize minStorageBufferOffsetAlignment;
int32_t minTexelOffset;
uint32_t maxTexelOffset;
int32_t minTexelGatherOffset;
uint32_t maxTexelGatherOffset;
float minInterpolationOffset;
float maxInterpolationOffset;
uint32_t subPixelInterpolationOffsetBits;
uint32_t maxFramebufferWidth;
uint32_t maxFramebufferHeight;
uint32_t maxFramebufferLayers;
VkSampleCountFlags framebufferColorSampleCounts;
VkSampleCountFlags framebufferDepthSampleCounts;
VkSampleCountFlags framebufferStencilSampleCounts;
VkSampleCountFlags framebufferNoAttachmentsSampleCounts;
uint32_t maxColorAttachments;
VkSampleCountFlags sampledImageColorSampleCounts;
VkSampleCountFlags sampledImageIntegerSampleCounts;
VkSampleCountFlags sampledImageDepthSampleCounts;
VkSampleCountFlags sampledImageStencilSampleCounts;
VkSampleCountFlags storageImageSampleCounts;
uint32_t maxSampleMaskWords;
VkBool32 timestampComputeAndGraphics;
float timestampPeriod;
uint32_t maxClipDistances;
uint32_t maxCullDistances;
uint32_t maxCombinedClipAndCullDistances;
uint32_t discreteQueuePriorities;
float pointSizeRange[2];
float lineWidthRange[2];
float pointSizeGranularity;
float lineWidthGranularity;
VkBool32 strictLines;
VkBool32 standardSampleLocations;
VkDeviceSize optimalBufferCopyOffsetAlignment;
VkDeviceSize optimalBufferCopyRowPitchAlignment;
VkDeviceSize nonCoherentAtomSize;
} VkPhysicalDeviceLimits;
-
maxImageDimension1Dis the maximum dimension (width) supported for all images created with animageTypeofVK_IMAGE_TYPE_1D. -
maxImageDimension2Dis the maximum dimension (widthorheight) supported for all images created with animageTypeofVK_IMAGE_TYPE_2Dand withoutVK_IMAGE_CREATE_CUBE_COMPATIBLE_BITset inflags. -
maxImageDimension3Dis the maximum dimension (width,height, ordepth) supported for all images created with animageTypeofVK_IMAGE_TYPE_3D. -
maxImageDimensionCubeis the maximum dimension (widthorheight) supported for all images created with animageTypeofVK_IMAGE_TYPE_2Dand withVK_IMAGE_CREATE_CUBE_COMPATIBLE_BITset inflags. -
maxImageArrayLayersis the maximum number of layers (arrayLayers) for an image. -
maxTexelBufferElementsis the maximum number of addressable texels for a buffer view created on a buffer which was created with theVK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BITorVK_BUFFER_USAGE_STORAGE_TEXEL_BUFFER_BITset in theusagemember of theVkBufferCreateInfostructure. -
maxUniformBufferRangeis the maximum value that can be specified in therangemember of any VkDescriptorBufferInfo structures passed to a call to vkUpdateDescriptorSets for descriptors of typeVK_DESCRIPTOR_TYPE_UNIFORM_BUFFERorVK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC. -
maxStorageBufferRangeis the maximum value that can be specified in therangemember of any VkDescriptorBufferInfo structures passed to a call to vkUpdateDescriptorSets for descriptors of typeVK_DESCRIPTOR_TYPE_STORAGE_BUFFERorVK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC. -
maxPushConstantsSizeis the maximum size, in bytes, of the pool of push constant memory. For each of the push constant ranges indicated by thepPushConstantRangesmember of theVkPipelineLayoutCreateInfostructure, (offset+size) must be less than or equal to this limit. -
maxMemoryAllocationCountis the maximum number of device memory allocations, as created by vkAllocateMemory, which can simultaneously exist. -
maxSamplerAllocationCountis the maximum number of sampler objects, as created by vkCreateSampler, which can simultaneously exist on a device. -
bufferImageGranularityis the granularity, in bytes, at which buffer or linear image resources, and optimal image resources can be bound to adjacent offsets in the sameVkDeviceMemoryobject without aliasing. See Buffer-Image Granularity for more details. -
sparseAddressSpaceSizeis the total amount of address space available, in bytes, for sparse memory resources. This is an upper bound on the sum of the size of all sparse resources, regardless of whether any memory is bound to them. -
maxBoundDescriptorSetsis the maximum number of descriptor sets that can be simultaneously used by a pipeline. AllDescriptorSetdecorations in shader modules must have a value less thanmaxBoundDescriptorSets. See Descriptor Sets. -
maxPerStageDescriptorSamplersis the maximum number of samplers that can be accessible to a single shader stage in a pipeline layout. Descriptors with a type ofVK_DESCRIPTOR_TYPE_SAMPLERorVK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLERcount against this limit. Only descriptors in descriptor set layouts created without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set count against this limit. A descriptor is accessible to a shader stage when thestageFlagsmember of theVkDescriptorSetLayoutBindingstructure has the bit for that shader stage set. See Sampler and Combined Image Sampler. -
maxPerStageDescriptorUniformBuffersis the maximum number of uniform buffers that can be accessible to a single shader stage in a pipeline layout. Descriptors with a type ofVK_DESCRIPTOR_TYPE_UNIFORM_BUFFERorVK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMICcount against this limit. Only descriptors in descriptor set layouts created without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set count against this limit. A descriptor is accessible to a shader stage when thestageFlagsmember of theVkDescriptorSetLayoutBindingstructure has the bit for that shader stage set. See Uniform Buffer and Dynamic Uniform Buffer. -
maxPerStageDescriptorStorageBuffersis the maximum number of storage buffers that can be accessible to a single shader stage in a pipeline layout. Descriptors with a type ofVK_DESCRIPTOR_TYPE_STORAGE_BUFFERorVK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMICcount against this limit. Only descriptors in descriptor set layouts created without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set count against this limit. A descriptor is accessible to a pipeline shader stage when thestageFlagsmember of theVkDescriptorSetLayoutBindingstructure has the bit for that shader stage set. See Storage Buffer and Dynamic Storage Buffer. -
maxPerStageDescriptorSampledImagesis the maximum number of sampled images that can be accessible to a single shader stage in a pipeline layout. Descriptors with a type ofVK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER,VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE, orVK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFERcount against this limit. Only descriptors in descriptor set layouts created without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set count against this limit. A descriptor is accessible to a pipeline shader stage when thestageFlagsmember of theVkDescriptorSetLayoutBindingstructure has the bit for that shader stage set. See Combined Image Sampler, Sampled Image, and Uniform Texel Buffer. -
maxPerStageDescriptorStorageImagesis the maximum number of storage images that can be accessible to a single shader stage in a pipeline layout. Descriptors with a type ofVK_DESCRIPTOR_TYPE_STORAGE_IMAGE, orVK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFERcount against this limit. Only descriptors in descriptor set layouts created without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set count against this limit. A descriptor is accessible to a pipeline shader stage when thestageFlagsmember of theVkDescriptorSetLayoutBindingstructure has the bit for that shader stage set. See Storage Image, and Storage Texel Buffer. -
maxPerStageDescriptorInputAttachmentsis the maximum number of input attachments that can be accessible to a single shader stage in a pipeline layout. Descriptors with a type ofVK_DESCRIPTOR_TYPE_INPUT_ATTACHMENTcount against this limit. Only descriptors in descriptor set layouts created without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set count against this limit. A descriptor is accessible to a pipeline shader stage when thestageFlagsmember of theVkDescriptorSetLayoutBindingstructure has the bit for that shader stage set. These are only supported for the fragment stage. See Input Attachment. -
maxPerStageResourcesis the maximum number of resources that can be accessible to a single shader stage in a pipeline layout. Descriptors with a type ofVK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER,VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE,VK_DESCRIPTOR_TYPE_STORAGE_IMAGE,VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER,VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER,VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,VK_DESCRIPTOR_TYPE_STORAGE_BUFFER,VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC,VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC, orVK_DESCRIPTOR_TYPE_INPUT_ATTACHMENTcount against this limit. Only descriptors in descriptor set layouts created without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set count against this limit. For the fragment shader stage the framebuffer color attachments also count against this limit. -
maxDescriptorSetSamplersis the maximum number of samplers that can be included in descriptor bindings in a pipeline layout across all pipeline shader stages and descriptor set numbers. Descriptors with a type ofVK_DESCRIPTOR_TYPE_SAMPLERorVK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLERcount against this limit. Only descriptors in descriptor set layouts created without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set count against this limit. See Sampler and Combined Image Sampler. -
maxDescriptorSetUniformBuffersis the maximum number of uniform buffers that can be included in descriptor bindings in a pipeline layout across all pipeline shader stages and descriptor set numbers. Descriptors with a type ofVK_DESCRIPTOR_TYPE_UNIFORM_BUFFERorVK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMICcount against this limit. Only descriptors in descriptor set layouts created without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set count against this limit. See Uniform Buffer and Dynamic Uniform Buffer. -
maxDescriptorSetUniformBuffersDynamicis the maximum number of dynamic uniform buffers that can be included in descriptor bindings in a pipeline layout across all pipeline shader stages and descriptor set numbers. Descriptors with a type ofVK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMICcount against this limit. Only descriptors in descriptor set layouts created without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set count against this limit. See Dynamic Uniform Buffer. -
maxDescriptorSetStorageBuffersis the maximum number of storage buffers that can be included in descriptor bindings in a pipeline layout across all pipeline shader stages and descriptor set numbers. Descriptors with a type ofVK_DESCRIPTOR_TYPE_STORAGE_BUFFERorVK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMICcount against this limit. Only descriptors in descriptor set layouts created without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set count against this limit. See Storage Buffer and Dynamic Storage Buffer. -
maxDescriptorSetStorageBuffersDynamicis the maximum number of dynamic storage buffers that can be included in descriptor bindings in a pipeline layout across all pipeline shader stages and descriptor set numbers. Descriptors with a type ofVK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMICcount against this limit. Only descriptors in descriptor set layouts created without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set count against this limit. See Dynamic Storage Buffer. -
maxDescriptorSetSampledImagesis the maximum number of sampled images that can be included in descriptor bindings in a pipeline layout across all pipeline shader stages and descriptor set numbers. Descriptors with a type ofVK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER,VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE, orVK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFERcount against this limit. Only descriptors in descriptor set layouts created without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set count against this limit. See Combined Image Sampler, Sampled Image, and Uniform Texel Buffer. -
maxDescriptorSetStorageImagesis the maximum number of storage images that can be included in descriptor bindings in a pipeline layout across all pipeline shader stages and descriptor set numbers. Descriptors with a type ofVK_DESCRIPTOR_TYPE_STORAGE_IMAGE, orVK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFERcount against this limit. Only descriptors in descriptor set layouts created without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set count against this limit. See Storage Image, and Storage Texel Buffer. -
maxDescriptorSetInputAttachmentsis the maximum number of input attachments that can be included in descriptor bindings in a pipeline layout across all pipeline shader stages and descriptor set numbers. Descriptors with a type ofVK_DESCRIPTOR_TYPE_INPUT_ATTACHMENTcount against this limit. Only descriptors in descriptor set layouts created without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set count against this limit. See Input Attachment. -
maxVertexInputAttributesis the maximum number of vertex input attributes that can be specified for a graphics pipeline. These are described in the array ofVkVertexInputAttributeDescriptionstructures that are provided at graphics pipeline creation time via thepVertexAttributeDescriptionsmember of theVkPipelineVertexInputStateCreateInfostructure. See Vertex Attributes and Vertex Input Description. -
maxVertexInputBindingsis the maximum number of vertex buffers that can be specified for providing vertex attributes to a graphics pipeline. These are described in the array ofVkVertexInputBindingDescriptionstructures that are provided at graphics pipeline creation time via thepVertexBindingDescriptionsmember of theVkPipelineVertexInputStateCreateInfostructure. Thebindingmember ofVkVertexInputBindingDescriptionmust be less than this limit. See Vertex Input Description. -
maxVertexInputAttributeOffsetis the maximum vertex input attribute offset that can be added to the vertex input binding stride. Theoffsetmember of theVkVertexInputAttributeDescriptionstructure must be less than or equal to this limit. See Vertex Input Description. -
maxVertexInputBindingStrideis the maximum vertex input binding stride that can be specified in a vertex input binding. Thestridemember of theVkVertexInputBindingDescriptionstructure must be less than or equal to this limit. See Vertex Input Description. -
maxVertexOutputComponentsis the maximum number of components of output variables which can be output by a vertex shader. See Vertex Shaders. -
maxTessellationGenerationLevelis the maximum tessellation generation level supported by the fixed-function tessellation primitive generator. See Tessellation. -
maxTessellationPatchSizeis the maximum patch size, in vertices, of patches that can be processed by the tessellation control shader and tessellation primitive generator. ThepatchControlPointsmember of theVkPipelineTessellationStateCreateInfostructure specified at pipeline creation time and the value provided in theOutputVerticesexecution mode of shader modules must be less than or equal to this limit. See Tessellation. -
maxTessellationControlPerVertexInputComponentsis the maximum number of components of input variables which can be provided as per-vertex inputs to the tessellation control shader stage. -
maxTessellationControlPerVertexOutputComponentsis the maximum number of components of per-vertex output variables which can be output from the tessellation control shader stage. -
maxTessellationControlPerPatchOutputComponentsis the maximum number of components of per-patch output variables which can be output from the tessellation control shader stage. -
maxTessellationControlTotalOutputComponentsis the maximum total number of components of per-vertex and per-patch output variables which can be output from the tessellation control shader stage. -
maxTessellationEvaluationInputComponentsis the maximum number of components of input variables which can be provided as per-vertex inputs to the tessellation evaluation shader stage. -
maxTessellationEvaluationOutputComponentsis the maximum number of components of per-vertex output variables which can be output from the tessellation evaluation shader stage. -
maxGeometryShaderInvocationsis the maximum invocation count supported for instanced geometry shaders. The value provided in theInvocationsexecution mode of shader modules must be less than or equal to this limit. See Geometry Shading. -
maxGeometryInputComponentsis the maximum number of components of input variables which can be provided as inputs to the geometry shader stage. -
maxGeometryOutputComponentsis the maximum number of components of output variables which can be output from the geometry shader stage. -
maxGeometryOutputVerticesis the maximum number of vertices which can be emitted by any geometry shader. -
maxGeometryTotalOutputComponentsis the maximum total number of components of output, across all emitted vertices, which can be output from the geometry shader stage. -
maxFragmentInputComponentsis the maximum number of components of input variables which can be provided as inputs to the fragment shader stage. -
maxFragmentOutputAttachmentsis the maximum number of output attachments which can be written to by the fragment shader stage. -
maxFragmentDualSrcAttachmentsis the maximum number of output attachments which can be written to by the fragment shader stage when blending is enabled and one of the dual source blend modes is in use. See Dual-Source Blending and dualSrcBlend. -
maxFragmentCombinedOutputResourcesis the total number of storage buffers, storage images, and output buffers which can be used in the fragment shader stage. -
maxComputeSharedMemorySizeis the maximum total storage size, in bytes, of all variables declared with theWorkgroupLocalstorage class in shader modules (or with thesharedstorage qualifier in GLSL) in the compute shader stage. -
maxComputeWorkGroupCount[3] is the maximum number of local workgroups that can be dispatched by a single dispatch command. These three values represent the maximum number of local workgroups for the X, Y, and Z dimensions, respectively. The workgroup count parameters to the dispatch commands must be less than or equal to the corresponding limit. See Dispatching Commands. -
maxComputeWorkGroupInvocationsis the maximum total number of compute shader invocations in a single local workgroup. The product of the X, Y, and Z sizes as specified by theLocalSizeexecution mode in shader modules and by the object decorated by theWorkgroupSizedecoration must be less than or equal to this limit. -
maxComputeWorkGroupSize[3] is the maximum size of a local compute workgroup, per dimension. These three values represent the maximum local workgroup size in the X, Y, and Z dimensions, respectively. Thex,y, andzsizes specified by theLocalSizeexecution mode and by the object decorated by theWorkgroupSizedecoration in shader modules must be less than or equal to the corresponding limit. -
subPixelPrecisionBitsis the number of bits of subpixel precision in framebuffer coordinates xf and yf. See Rasterization. -
subTexelPrecisionBitsis the number of bits of precision in the division along an axis of an image used for minification and magnification filters. 2subTexelPrecisionBitsis the actual number of divisions along each axis of the image represented. Sub-texel values calculated during image sampling will snap to these locations when generating the filtered results. -
mipmapPrecisionBitsis the number of bits of division that the LOD calculation for mipmap fetching get snapped to when determining the contribution from each mip level to the mip filtered results. 2mipmapPrecisionBitsis the actual number of divisions.NoteFor example, if this value is 2 bits then when linearly filtering between two levels, each level could: contribute: 0%, 33%, 66%, or 100% (this is just an example and the amount of contribution should be covered by different equations in the spec).
-
maxDrawIndexedIndexValueis the maximum index value that can be used for indexed draw calls when using 32-bit indices. This excludes the primitive restart index value of 0xFFFFFFFF. See fullDrawIndexUint32. -
maxDrawIndirectCountis the maximum draw count that is supported for indirect draw calls. See multiDrawIndirect. -
maxSamplerLodBiasis the maximum absolute sampler LOD bias. The sum of themipLodBiasmember of theVkSamplerCreateInfostructure and theBiasoperand of image sampling operations in shader modules (or 0 if noBiasoperand is provided to an image sampling operation) are clamped to the range [-maxSamplerLodBias,+maxSamplerLodBias]. See [samplers-mipLodBias]. -
maxSamplerAnisotropyis the maximum degree of sampler anisotropy. The maximum degree of anisotropic filtering used for an image sampling operation is the minimum of themaxAnisotropymember of theVkSamplerCreateInfostructure and this limit. See [samplers-maxAnisotropy]. -
maxViewportsis the maximum number of active viewports. TheviewportCountmember of theVkPipelineViewportStateCreateInfostructure that is provided at pipeline creation must be less than or equal to this limit. -
maxViewportDimensions[2] are the maximum viewport dimensions in the X (width) and Y (height) dimensions, respectively. The maximum viewport dimensions must be greater than or equal to the largest image which can be created and used as a framebuffer attachment. See Controlling the Viewport. -
viewportBoundsRange[2] is the [minimum, maximum] range that the corners of a viewport must be contained in. This range must be at least [-2 ×size, 2 ×size- 1], wheresize= max(maxViewportDimensions[0],maxViewportDimensions[1]). See Controlling the Viewport.NoteThe intent of the
viewportBoundsRangelimit is to allow a maximum sized viewport to be arbitrarily shifted relative to the output target as long as at least some portion intersects. This would give a bounds limit of [-size+ 1, 2 ×size- 1] which would allow all possible non-empty-set intersections of the output target and the viewport. Since these numbers are typically powers of two, picking the signed number range using the smallest possible number of bits ends up with the specified range. -
viewportSubPixelBitsis the number of bits of subpixel precision for viewport bounds. The subpixel precision that floating-point viewport bounds are interpreted at is given by this limit. -
minMemoryMapAlignmentis the minimum required alignment, in bytes, of host visible memory allocations within the host address space. When mapping a memory allocation with vkMapMemory, subtractingoffsetbytes from the returned pointer will always produce an integer multiple of this limit. See Host Access to Device Memory Objects. -
minTexelBufferOffsetAlignmentis the minimum required alignment, in bytes, for theoffsetmember of theVkBufferViewCreateInfostructure for texel buffers. When a buffer view is created for a buffer which was created withVK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BITorVK_BUFFER_USAGE_STORAGE_TEXEL_BUFFER_BITset in theusagemember of theVkBufferCreateInfostructure, theoffsetmust be an integer multiple of this limit. -
minUniformBufferOffsetAlignmentis the minimum required alignment, in bytes, for theoffsetmember of theVkDescriptorBufferInfostructure for uniform buffers. When a descriptor of typeVK_DESCRIPTOR_TYPE_UNIFORM_BUFFERorVK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMICis updated, theoffsetmust be an integer multiple of this limit. Similarly, dynamic offsets for uniform buffers must be multiples of this limit. -
minStorageBufferOffsetAlignmentis the minimum required alignment, in bytes, for theoffsetmember of theVkDescriptorBufferInfostructure for storage buffers. When a descriptor of typeVK_DESCRIPTOR_TYPE_STORAGE_BUFFERorVK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMICis updated, theoffsetmust be an integer multiple of this limit. Similarly, dynamic offsets for storage buffers must be multiples of this limit. -
minTexelOffsetis the minimum offset value for theConstOffsetimage operand of any of theOpImageSample* orOpImageFetch* image instructions. -
maxTexelOffsetis the maximum offset value for theConstOffsetimage operand of any of theOpImageSample* orOpImageFetch* image instructions. -
minTexelGatherOffsetis the minimum offset value for theOffsetorConstOffsetsimage operands of any of theOpImage*Gatherimage instructions. -
maxTexelGatherOffsetis the maximum offset value for theOffsetorConstOffsetsimage operands of any of theOpImage*Gatherimage instructions. -
minInterpolationOffsetis the minimum negative offset value for theoffsetoperand of theInterpolateAtOffsetextended instruction. -
maxInterpolationOffsetis the maximum positive offset value for theoffsetoperand of theInterpolateAtOffsetextended instruction. -
subPixelInterpolationOffsetBitsis the number of subpixel fractional bits that thexandyoffsets to theInterpolateAtOffsetextended instruction may be rounded to as fixed-point values. -
maxFramebufferWidthis the maximum width for a framebuffer. Thewidthmember of theVkFramebufferCreateInfostructure must be less than or equal to this limit. -
maxFramebufferHeightis the maximum height for a framebuffer. Theheightmember of theVkFramebufferCreateInfostructure must be less than or equal to this limit. -
maxFramebufferLayersis the maximum layer count for a layered framebuffer. Thelayersmember of theVkFramebufferCreateInfostructure must be less than or equal to this limit. -
framebufferColorSampleCountsis a bitmask1 of VkSampleCountFlagBits indicating the color sample counts that are supported for all framebuffer color attachments with floating- or fixed-point formats. There is no limit that specifies the color sample counts that are supported for all color attachments with integer formats. -
framebufferDepthSampleCountsis a bitmask1 of VkSampleCountFlagBits indicating the supported depth sample counts for all framebuffer depth/stencil attachments, when the format includes a depth component. -
framebufferStencilSampleCountsis a bitmask1 of VkSampleCountFlagBits indicating the supported stencil sample counts for all framebuffer depth/stencil attachments, when the format includes a stencil component. -
framebufferNoAttachmentsSampleCountsis a bitmask1 of VkSampleCountFlagBits indicating the supported sample counts for a framebuffer with no attachments. -
maxColorAttachmentsis the maximum number of color attachments that can be used by a subpass in a render pass. ThecolorAttachmentCountmember of theVkSubpassDescriptionstructure must be less than or equal to this limit. -
sampledImageColorSampleCountsis a bitmask1 of VkSampleCountFlagBits indicating the sample counts supported for all 2D images created withVK_IMAGE_TILING_OPTIMAL,usagecontainingVK_IMAGE_USAGE_SAMPLED_BIT, and a non-integer color format. -
sampledImageIntegerSampleCountsis a bitmask1 of VkSampleCountFlagBits indicating the sample counts supported for all 2D images created withVK_IMAGE_TILING_OPTIMAL,usagecontainingVK_IMAGE_USAGE_SAMPLED_BIT, and an integer color format. -
sampledImageDepthSampleCountsis a bitmask1 of VkSampleCountFlagBits indicating the sample counts supported for all 2D images created withVK_IMAGE_TILING_OPTIMAL,usagecontainingVK_IMAGE_USAGE_SAMPLED_BIT, and a depth format. -
sampledImageStencilSampleCountsis a bitmask1 of VkSampleCountFlagBits indicating the sample supported for all 2D images created withVK_IMAGE_TILING_OPTIMAL,usagecontainingVK_IMAGE_USAGE_SAMPLED_BIT, and a stencil format. -
storageImageSampleCountsis a bitmask1 of VkSampleCountFlagBits indicating the sample counts supported for all 2D images created withVK_IMAGE_TILING_OPTIMAL, andusagecontainingVK_IMAGE_USAGE_STORAGE_BIT. -
maxSampleMaskWordsis the maximum number of array elements of a variable decorated with theSampleMaskbuilt-in decoration. -
timestampComputeAndGraphicsspecifies support for timestamps on all graphics and compute queues. If this limit is set toVK_TRUE, all queues that advertise theVK_QUEUE_GRAPHICS_BITorVK_QUEUE_COMPUTE_BITin theVkQueueFamilyProperties::queueFlagssupportVkQueueFamilyProperties::timestampValidBitsof at least 36. See Timestamp Queries. -
timestampPeriodis the number of nanoseconds required for a timestamp query to be incremented by 1. See Timestamp Queries. -
maxClipDistancesis the maximum number of clip distances that can be used in a single shader stage. The size of any array declared with theClipDistancebuilt-in decoration in a shader module must be less than or equal to this limit. -
maxCullDistancesis the maximum number of cull distances that can be used in a single shader stage. The size of any array declared with theCullDistancebuilt-in decoration in a shader module must be less than or equal to this limit. -
maxCombinedClipAndCullDistancesis the maximum combined number of clip and cull distances that can be used in a single shader stage. The sum of the sizes of any pair of arrays declared with theClipDistanceandCullDistancebuilt-in decoration used by a single shader stage in a shader module must be less than or equal to this limit. -
discreteQueuePrioritiesis the number of discrete priorities that can be assigned to a queue based on the value of each member ofVkDeviceQueueCreateInfo::pQueuePriorities. This must be at least 2, and levels must be spread evenly over the range, with at least one level at 1.0, and another at 0.0. See Queue Priority. -
pointSizeRange[2] is the range [minimum,maximum] of supported sizes for points. Values written to variables decorated with thePointSizebuilt-in decoration are clamped to this range. -
lineWidthRange[2] is the range [minimum,maximum] of supported widths for lines. Values specified by thelineWidthmember of theVkPipelineRasterizationStateCreateInfoor thelineWidthparameter tovkCmdSetLineWidthare clamped to this range. -
pointSizeGranularityis the granularity of supported point sizes. Not all point sizes in the range defined bypointSizeRangeare supported. This limit specifies the granularity (or increment) between successive supported point sizes. -
lineWidthGranularityis the granularity of supported line widths. Not all line widths in the range defined bylineWidthRangeare supported. This limit specifies the granularity (or increment) between successive supported line widths. -
strictLinesspecifies whether lines are rasterized according to the preferred method of rasterization. If set toVK_FALSE, lines may be rasterized under a relaxed set of rules. If set toVK_TRUE, lines are rasterized as per the strict definition. See Basic Line Segment Rasterization. -
standardSampleLocationsspecifies whether rasterization uses the standard sample locations as documented in Multisampling. If set toVK_TRUE, the implementation uses the documented sample locations. If set toVK_FALSE, the implementation may use different sample locations. -
optimalBufferCopyOffsetAlignmentis the optimal buffer offset alignment in bytes forvkCmdCopyBufferToImageandvkCmdCopyImageToBuffer. The per texel alignment requirements are enforced, but applications should use the optimal alignment for optimal performance and power use. -
optimalBufferCopyRowPitchAlignmentis the optimal buffer row pitch alignment in bytes forvkCmdCopyBufferToImageandvkCmdCopyImageToBuffer. Row pitch is the number of bytes between texels with the same X coordinate in adjacent rows (Y coordinates differ by one). The per texel alignment requirements are enforced, but applications should use the optimal alignment for optimal performance and power use. -
nonCoherentAtomSizeis the size and alignment in bytes that bounds concurrent access to host-mapped device memory. -
VkPhysicalDeviceDiscardRectanglePropertiesEXT::
maxDiscardRectanglesis the maximum number of active discard rectangles. This limit can be queried by setting thepNextpointer from a VkPhysicalDeviceProperties2 object to an instance of VkPhysicalDeviceDiscardRectanglePropertiesEXT and usingvkGetPhysicalDeviceProperties2to fill out the members. -
VkPhysicalDevicePointClippingProperties::
pointClippingBehaviordefines the clipping behavior of points. This limit can be queried by setting thepNextpointer from a VkPhysicalDeviceProperties2 object to an instance of VkPhysicalDevicePointClippingProperties and usingvkGetPhysicalDeviceProperties2to fill out the members. -
VkPhysicalDeviceVertexAttributeDivisorPropertiesEXT::maxVertexAttribDivisoris the maximum value of the number of instances that will repeat the value of vertex attribute data when instanced rendering is enabled. This limit can be queried by setting thepNextpointer from a VkPhysicalDeviceProperties2 object to an instance of VkPhysicalDeviceVertexAttributeDivisorPropertiesEXT and usingvkGetPhysicalDeviceProperties2to fill out the members.
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-
For all bitmasks of VkSampleCountFlagBits, the sample count limits defined above represent the minimum supported sample counts for each image type. Individual images may support additional sample counts, which are queried using vkGetPhysicalDeviceImageFormatProperties as described in Supported Sample Counts.
Bits which may be set in the sample count limits returned by VkPhysicalDeviceLimits, as well as in other queries and structures representing image sample counts, are:
typedef enum VkSampleCountFlagBits {
VK_SAMPLE_COUNT_1_BIT = 0x00000001,
VK_SAMPLE_COUNT_2_BIT = 0x00000002,
VK_SAMPLE_COUNT_4_BIT = 0x00000004,
VK_SAMPLE_COUNT_8_BIT = 0x00000008,
VK_SAMPLE_COUNT_16_BIT = 0x00000010,
VK_SAMPLE_COUNT_32_BIT = 0x00000020,
VK_SAMPLE_COUNT_64_BIT = 0x00000040,
} VkSampleCountFlagBits;
-
VK_SAMPLE_COUNT_1_BITspecifies an image with one sample per pixel. -
VK_SAMPLE_COUNT_2_BITspecifies an image with 2 samples per pixel. -
VK_SAMPLE_COUNT_4_BITspecifies an image with 4 samples per pixel. -
VK_SAMPLE_COUNT_8_BITspecifies an image with 8 samples per pixel. -
VK_SAMPLE_COUNT_16_BITspecifies an image with 16 samples per pixel. -
VK_SAMPLE_COUNT_32_BITspecifies an image with 32 samples per pixel. -
VK_SAMPLE_COUNT_64_BITspecifies an image with 64 samples per pixel.
typedef VkFlags VkSampleCountFlags;
VkSampleCountFlags is a bitmask type for setting a mask of zero or
more VkSampleCountFlagBits.
The VkPhysicalDevicePushDescriptorPropertiesKHR structure is defined
as:
typedef struct VkPhysicalDevicePushDescriptorPropertiesKHR {
VkStructureType sType;
void* pNext;
uint32_t maxPushDescriptors;
} VkPhysicalDevicePushDescriptorPropertiesKHR;
The members of the VkPhysicalDevicePushDescriptorPropertiesKHR
structure describe the following implementation-dependent limits:
The VkPhysicalDeviceMultiviewProperties structure is defined as:
typedef struct VkPhysicalDeviceMultiviewProperties {
VkStructureType sType;
void* pNext;
uint32_t maxMultiviewViewCount;
uint32_t maxMultiviewInstanceIndex;
} VkPhysicalDeviceMultiviewProperties;
or the equivalent
typedef VkPhysicalDeviceMultiviewProperties VkPhysicalDeviceMultiviewPropertiesKHR;
The members of the VkPhysicalDeviceMultiviewProperties structure
describe the following implementation-dependent limits:
If the VkPhysicalDeviceMultiviewProperties structure is included in
the pNext chain of VkPhysicalDeviceProperties2, it is filled
with the implementation-dependent limits.
The VkPhysicalDeviceDiscardRectanglePropertiesEXT structure is defined
as:
typedef struct VkPhysicalDeviceDiscardRectanglePropertiesEXT {
VkStructureType sType;
void* pNext;
uint32_t maxDiscardRectangles;
} VkPhysicalDeviceDiscardRectanglePropertiesEXT;
The members of the VkPhysicalDeviceDiscardRectanglePropertiesEXT
structure describe the following implementation-dependent limits:
-
maxDiscardRectanglesis the maximum number of discard rectangles that can be specified.
If the VkPhysicalDeviceDiscardRectanglePropertiesEXT structure is
included in the pNext chain of VkPhysicalDeviceProperties2, it
is filled with the implementation-dependent limits.
The VkPhysicalDeviceSampleLocationsPropertiesEXT structure is defined
as:
typedef struct VkPhysicalDeviceSampleLocationsPropertiesEXT {
VkStructureType sType;
void* pNext;
VkSampleCountFlags sampleLocationSampleCounts;
VkExtent2D maxSampleLocationGridSize;
float sampleLocationCoordinateRange[2];
uint32_t sampleLocationSubPixelBits;
VkBool32 variableSampleLocations;
} VkPhysicalDeviceSampleLocationsPropertiesEXT;
The members of the VkPhysicalDeviceSampleLocationsPropertiesEXT
structure describe the following implementation-dependent limits:
-
sampleLocationSampleCountsis a bitmask of VkSampleCountFlagBits indicating the sample counts supporting custom sample locations. -
maxSampleLocationGridSizeis the maximum size of the pixel grid in which sample locations can vary that is supported for all sample counts insampleLocationSampleCounts. -
sampleLocationCoordinateRange[2] is the range of supported sample location coordinates. -
sampleLocationSubPixelBitsis the number of bits of subpixel precision for sample locations. -
variableSampleLocationsspecifies whether the sample locations used by all pipelines that will be bound to a command buffer during a subpass must match. If set toVK_TRUE, the implementation supports variable sample locations in a subpass. If set toVK_FALSE, then the sample locations must stay constant in each subpass.
If the VkPhysicalDeviceSampleLocationsPropertiesEXT structure is
included in the pNext chain of VkPhysicalDeviceProperties2, it
is filled with the implementation-dependent limits.
The VkPhysicalDeviceExternalMemoryHostPropertiesEXT structure is
defined as:
typedef struct VkPhysicalDeviceExternalMemoryHostPropertiesEXT {
VkStructureType sType;
void* pNext;
VkDeviceSize minImportedHostPointerAlignment;
} VkPhysicalDeviceExternalMemoryHostPropertiesEXT;
The members of the VkPhysicalDeviceExternalMemoryHostPropertiesEXT
structure describe the following implementation-dependent limits:
If the VkPhysicalDeviceExternalMemoryHostPropertiesEXT structure is
included in the pNext chain of VkPhysicalDeviceProperties2KHR,
it is filled with the implementation-dependent limits.
The VkPhysicalDeviceMultiviewPerViewAttributesPropertiesNVX structure
is defined as:
typedef struct VkPhysicalDeviceMultiviewPerViewAttributesPropertiesNVX {
VkStructureType sType;
void* pNext;
VkBool32 perViewPositionAllComponents;
} VkPhysicalDeviceMultiviewPerViewAttributesPropertiesNVX;
The members of the
VkPhysicalDeviceMultiviewPerViewAttributesPropertiesNVX structure
describe the following implementation-dependent limits:
If the VkPhysicalDeviceMultiviewPerViewAttributesPropertiesNVX
structure is included in the pNext chain of
VkPhysicalDeviceProperties2, it is filled with the
implementation-dependent limits.
The VkPhysicalDevicePointClippingProperties structure is defined as:
typedef struct VkPhysicalDevicePointClippingProperties {
VkStructureType sType;
void* pNext;
VkPointClippingBehavior pointClippingBehavior;
} VkPhysicalDevicePointClippingProperties;
or the equivalent
typedef VkPhysicalDevicePointClippingProperties VkPhysicalDevicePointClippingPropertiesKHR;
The members of the VkPhysicalDevicePointClippingProperties structure
describe the following implementation-dependent limit:
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
pointClippingBehavioris the point clipping behavior supported by the implementation, and is of type VkPointClippingBehavior.
If the VkPhysicalDevicePointClippingProperties structure is included
in the pNext chain of VkPhysicalDeviceProperties2, it is filled
with the implementation-dependent limits.
The VkPhysicalDeviceSubgroupProperties structure is defined as:
typedef struct VkPhysicalDeviceSubgroupProperties {
VkStructureType sType;
void* pNext;
uint32_t subgroupSize;
VkShaderStageFlags supportedStages;
VkSubgroupFeatureFlags supportedOperations;
VkBool32 quadOperationsInAllStages;
} VkPhysicalDeviceSubgroupProperties;
The members of the VkPhysicalDeviceSubgroupProperties structure
describe the following implementation-dependent limits:
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
subgroupSizeis the number of invocations in each subgroup. This will match anySubgroupSizedecorated variable used in any shader module created on this device.subgroupSizeis at least 1 if any of the physical device’s queues supportVK_QUEUE_GRAPHICS_BITorVK_QUEUE_COMPUTE_BIT. -
supportedStagesis a bitfield of VkShaderStageFlagBits describing the shader stages that subgroup operations are supported in.supportedStageswill have theVK_SHADER_STAGE_COMPUTE_BITbit set if any of any of the physical device’s queues supportVK_QUEUE_COMPUTE_BIT. -
supportedOperationsis a bitmask of VkSubgroupFeatureFlagBits specifying the sets of subgroup operations supported on this device.supportedOperationswill have theVK_SUBGROUP_FEATURE_BASIC_BITbit set if any of the physical device’s queues supportVK_QUEUE_GRAPHICS_BITorVK_QUEUE_COMPUTE_BIT. -
quadOperationsInAllStagesis a boolean that specifies whether quad subgroup operations are available in all stages, or are restricted to fragment and compute stages.
If the VkPhysicalDeviceSubgroupProperties structure is included in the
pNext chain of VkPhysicalDeviceProperties2, it is filled with
the implementation-dependent limits.
Bits which can be set in
VkPhysicalDeviceSubgroupProperties::supportedOperations to
specify supported subgroup operations are:
typedef enum VkSubgroupFeatureFlagBits {
VK_SUBGROUP_FEATURE_BASIC_BIT = 0x00000001,
VK_SUBGROUP_FEATURE_VOTE_BIT = 0x00000002,
VK_SUBGROUP_FEATURE_ARITHMETIC_BIT = 0x00000004,
VK_SUBGROUP_FEATURE_BALLOT_BIT = 0x00000008,
VK_SUBGROUP_FEATURE_SHUFFLE_BIT = 0x00000010,
VK_SUBGROUP_FEATURE_SHUFFLE_RELATIVE_BIT = 0x00000020,
VK_SUBGROUP_FEATURE_CLUSTERED_BIT = 0x00000040,
VK_SUBGROUP_FEATURE_QUAD_BIT = 0x00000080,
VK_SUBGROUP_FEATURE_PARTITIONED_BIT_NV = 0x00000100,
} VkSubgroupFeatureFlagBits;
-
VK_SUBGROUP_FEATURE_BASIC_BITspecifies the device will accept SPIR-V shader modules that contain theGroupNonUniformcapability. -
VK_SUBGROUP_FEATURE_VOTE_BITspecifies the device will accept SPIR-V shader modules that contain theGroupNonUniformVotecapability. -
VK_SUBGROUP_FEATURE_ARITHMETIC_BITspecifies the device will accept SPIR-V shader modules that contain theGroupNonUniformArithmeticcapability. -
VK_SUBGROUP_FEATURE_BALLOT_BITspecifies the device will accept SPIR-V shader modules that contain theGroupNonUniformBallotcapability. -
VK_SUBGROUP_FEATURE_SHUFFLE_BITspecifies the device will accept SPIR-V shader modules that contain theGroupNonUniformShufflecapability. -
VK_SUBGROUP_FEATURE_SHUFFLE_RELATIVE_BITspecifies the device will accept SPIR-V shader modules that contain theGroupNonUniformShuffleRelativecapability. -
VK_SUBGROUP_FEATURE_CLUSTERED_BITspecifies the device will accept SPIR-V shader modules that contain theGroupNonUniformClusteredcapability. -
VK_SUBGROUP_FEATURE_QUAD_BITspecifies the device will accept SPIR-V shader modules that contain theGroupNonUniformQuadcapability. -
VK_SUBGROUP_FEATURE_PARTITIONED_BIT_NVspecifies the device will accept SPIR-V shader modules that contain theGroupNonUniformPartitionedNVcapability.
typedef VkFlags VkSubgroupFeatureFlags;
VkSubgroupFeatureFlags is a bitmask type for setting a mask of zero or
more VkSubgroupFeatureFlagBits.
The VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT structure is
defined as:
typedef struct VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT {
VkStructureType sType;
void* pNext;
uint32_t advancedBlendMaxColorAttachments;
VkBool32 advancedBlendIndependentBlend;
VkBool32 advancedBlendNonPremultipliedSrcColor;
VkBool32 advancedBlendNonPremultipliedDstColor;
VkBool32 advancedBlendCorrelatedOverlap;
VkBool32 advancedBlendAllOperations;
} VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT;
The members of the VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT
structure describe the following implementation-dependent limits:
-
advancedBlendMaxColorAttachmentsis one greater than the highest color attachment index that can be used in a subpass, for a pipeline that uses an advanced blend operation. -
advancedBlendIndependentBlendspecifies whether advanced blend operations can vary per-attachment. -
advancedBlendNonPremultipliedSrcColorspecifies whether the source color can be treated as non-premultiplied. If this isVK_FALSE, then VkPipelineColorBlendAdvancedStateCreateInfoEXT::srcPremultipliedmust beVK_TRUE. -
advancedBlendNonPremultipliedDstColorspecifies whether the destination color can be treated as non-premultiplied. If this isVK_FALSE, then VkPipelineColorBlendAdvancedStateCreateInfoEXT::dstPremultipliedmust beVK_TRUE. -
advancedBlendCorrelatedOverlapspecifies whether the overlap mode can be treated as correlated. If this isVK_FALSE, then VkPipelineColorBlendAdvancedStateCreateInfoEXT::blendOverlapmust beVK_BLEND_OVERLAP_UNCORRELATED_EXT. -
advancedBlendAllOperationsspecifies whether all advanced blend operation enums are supported. See the valid usage of VkPipelineColorBlendAttachmentState.
If the VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT structure
is included in the pNext chain of VkPhysicalDeviceProperties2,
it is filled with the implementation-dependent limits.
The VkPhysicalDeviceVertexAttributeDivisorPropertiesEXT structure is
defined as:
typedef struct VkPhysicalDeviceVertexAttributeDivisorPropertiesEXT {
VkStructureType sType;
void* pNext;
uint32_t maxVertexAttribDivisor;
} VkPhysicalDeviceVertexAttributeDivisorPropertiesEXT;
The members of the VkPhysicalDeviceVertexAttributeDivisorPropertiesEXT
structure describe the following implementation-dependent limits:
The VkPhysicalDeviceSamplerFilterMinmaxPropertiesEXT structure is
defined as:
typedef struct VkPhysicalDeviceSamplerFilterMinmaxPropertiesEXT {
VkStructureType sType;
void* pNext;
VkBool32 filterMinmaxSingleComponentFormats;
VkBool32 filterMinmaxImageComponentMapping;
} VkPhysicalDeviceSamplerFilterMinmaxPropertiesEXT;
The members of the VkPhysicalDeviceSamplerFilterMinmaxPropertiesEXT
structure describe the following implementation-dependent limits:
-
filterMinmaxSingleComponentFormatsis a boolean value indicating whether a minimum set of required formats support min/max filtering. -
filterMinmaxImageComponentMappingis a boolean value indicating whether the implementation supports non-identity component mapping of the image when doing min/max filtering.
If the VkPhysicalDeviceSamplerFilterMinmaxPropertiesEXT structure is
included in the pNext chain of VkPhysicalDeviceProperties2, it
is filled with the implementation-dependent limits.
If filterMinmaxSingleComponentFormats is VK_TRUE, the following
formats must support the
VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_MINMAX_BIT_EXT feature with
VK_IMAGE_TILING_OPTIMAL, if they support
VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT.
-
VK_FORMAT_R8_UNORM -
VK_FORMAT_R8_SNORM -
VK_FORMAT_R16_UNORM -
VK_FORMAT_R16_SNORM -
VK_FORMAT_R16_SFLOAT -
VK_FORMAT_R32_SFLOAT -
VK_FORMAT_D16_UNORM -
VK_FORMAT_X8_D24_UNORM_PACK32 -
VK_FORMAT_D32_SFLOAT -
VK_FORMAT_D16_UNORM_S8_UINT -
VK_FORMAT_D24_UNORM_S8_UINT -
VK_FORMAT_D32_SFLOAT_S8_UINT
If the format is a depth/stencil format, this bit only specifies that the depth aspect (not the stencil aspect) of an image of this format supports min/max filtering, and that min/max filtering of the depth aspect is supported when depth compare is disabled in the sampler.
If filterMinmaxImageComponentMapping is VK_FALSE the component
mapping of the image view used with min/max filtering must have been
created with the r component set to
VK_COMPONENT_SWIZZLE_IDENTITY.
Only the r component of the sampled image value is defined and the
other component values are undefined.
If filterMinmaxImageComponentMapping is VK_TRUE this restriction
does not apply and image component mapping works as normal.
The VkPhysicalDeviceProtectedMemoryProperties structure is defined as:
typedef struct VkPhysicalDeviceProtectedMemoryProperties {
VkStructureType sType;
void* pNext;
VkBool32 protectedNoFault;
} VkPhysicalDeviceProtectedMemoryProperties;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
protectedNoFaultspecifies whether the undefined behavior will not include process termination or device loss. IfprotectedNoFaultisVK_FALSE, undefined behavior may include process termination or device loss. IfprotectedNoFaultisVK_TRUE, undefined behavior will not include process termination or device loss.
If the VkPhysicalDeviceProtectedMemoryProperties structure is included
in the pNext chain of VkPhysicalDeviceProperties2, it is filled
with a value indicating the implementation-dependent behavior.
The VkPhysicalDeviceMaintenance3Properties structure is defined as:
typedef struct VkPhysicalDeviceMaintenance3Properties {
VkStructureType sType;
void* pNext;
uint32_t maxPerSetDescriptors;
VkDeviceSize maxMemoryAllocationSize;
} VkPhysicalDeviceMaintenance3Properties;
or the equivalent
typedef VkPhysicalDeviceMaintenance3Properties VkPhysicalDeviceMaintenance3PropertiesKHR;
The members of the VkPhysicalDeviceMaintenance3Properties structure
describe the following implementation-dependent limits:
-
maxPerSetDescriptorsis a maximum number of descriptors (summed over all descriptor types) in a single descriptor set that is guaranteed to satisfy any implementation-dependent constraints on the size of a descriptor set itself. Applications can query whether a descriptor set that goes beyond this limit is supported using vkGetDescriptorSetLayoutSupport. -
maxMemoryAllocationSizeis the maximum size of a memory allocation that can be created, even if there is more space available in the heap.
If the VkPhysicalDeviceMaintenance3Properties structure is included in
the pNext chain of VkPhysicalDeviceProperties2, it is filled
with the implementation-dependent limits.
The VkPhysicalDeviceDescriptorIndexingPropertiesEXT structure is
defined as:
typedef struct VkPhysicalDeviceDescriptorIndexingPropertiesEXT {
VkStructureType sType;
void* pNext;
uint32_t maxUpdateAfterBindDescriptorsInAllPools;
VkBool32 shaderUniformBufferArrayNonUniformIndexingNative;
VkBool32 shaderSampledImageArrayNonUniformIndexingNative;
VkBool32 shaderStorageBufferArrayNonUniformIndexingNative;
VkBool32 shaderStorageImageArrayNonUniformIndexingNative;
VkBool32 shaderInputAttachmentArrayNonUniformIndexingNative;
VkBool32 robustBufferAccessUpdateAfterBind;
VkBool32 quadDivergentImplicitLod;
uint32_t maxPerStageDescriptorUpdateAfterBindSamplers;
uint32_t maxPerStageDescriptorUpdateAfterBindUniformBuffers;
uint32_t maxPerStageDescriptorUpdateAfterBindStorageBuffers;
uint32_t maxPerStageDescriptorUpdateAfterBindSampledImages;
uint32_t maxPerStageDescriptorUpdateAfterBindStorageImages;
uint32_t maxPerStageDescriptorUpdateAfterBindInputAttachments;
uint32_t maxPerStageUpdateAfterBindResources;
uint32_t maxDescriptorSetUpdateAfterBindSamplers;
uint32_t maxDescriptorSetUpdateAfterBindUniformBuffers;
uint32_t maxDescriptorSetUpdateAfterBindUniformBuffersDynamic;
uint32_t maxDescriptorSetUpdateAfterBindStorageBuffers;
uint32_t maxDescriptorSetUpdateAfterBindStorageBuffersDynamic;
uint32_t maxDescriptorSetUpdateAfterBindSampledImages;
uint32_t maxDescriptorSetUpdateAfterBindStorageImages;
uint32_t maxDescriptorSetUpdateAfterBindInputAttachments;
} VkPhysicalDeviceDescriptorIndexingPropertiesEXT;
The members of the VkPhysicalDeviceDescriptorIndexingPropertiesEXT
structure describe the following implementation-dependent limits:
-
maxUpdateAfterBindDescriptorsInAllPoolsis the maximum number of descriptors (summed over all descriptor types) that can be created across all pools that are created with theVK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT_EXTbit set. Pool creation may fail when this limit is exceeded, or when the space this limit represents can’t satisfy a pool creation due to fragmentation. -
shaderUniformBufferArrayNonUniformIndexingNativeis a boolean value indicating whether uniform buffer descriptors natively support nonuniform indexing. If this isVK_FALSE, then a single dynamic instance of an instruction that nonuniformly indexes an array of uniform buffers may execute multiple times in order to access all the descriptors. -
shaderSampledImageArrayNonUniformIndexingNativeis a boolean value indicating whether sampler and image descriptors natively support nonuniform indexing. If this isVK_FALSE, then a single dynamic instance of an instruction that nonuniformly indexes an array of samplers or images may execute multiple times in order to access all the descriptors. -
shaderStorageBufferArrayNonUniformIndexingNativeis a boolean value indicating whether storage buffer descriptors natively support nonuniform indexing. If this isVK_FALSE, then a single dynamic instance of an instruction that nonuniformly indexes an array of storage buffers may execute multiple times in order to access all the descriptors. -
shaderStorageImageArrayNonUniformIndexingNativeis a boolean value indicating whether storage image descriptors natively support nonuniform indexing. If this isVK_FALSE, then a single dynamic instance of an instruction that nonuniformly indexes an array of storage images may execute multiple times in order to access all the descriptors. -
shaderInputAttachmentArrayNonUniformIndexingNativeis a boolean value indicating whether input attachment descriptors natively support nonuniform indexing. If this isVK_FALSE, then a single dynamic instance of an instruction that nonuniformly indexes an array of input attachments may execute multiple times in order to access all the descriptors. -
robustBufferAccessUpdateAfterBindis a boolean value indicating whetherrobustBufferAccesscan be enabled in a device simultaneously withdescriptorBindingUniformBufferUpdateAfterBind,descriptorBindingStorageBufferUpdateAfterBind,descriptorBindingUniformTexelBufferUpdateAfterBind, and/ordescriptorBindingStorageTexelBufferUpdateAfterBind. If this isVK_FALSE, then eitherrobustBufferAccessmust be disabled or all of these update-after-bind features must be disabled. -
quadDivergentImplicitLodis a boolean value indicating whether implicit level of detail calculations for image operations have well-defined results when the image and/or sampler objects used for the instruction are not uniform within a quad. See Derivative Image Operations. -
maxPerStageDescriptorUpdateAfterBindSamplersis similar tomaxPerStageDescriptorSamplersbut counts descriptors from descriptor sets created with or without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set. -
maxPerStageDescriptorUpdateAfterBindUniformBuffersis similar tomaxPerStageDescriptorUniformBuffersbut counts descriptors from descriptor sets created with or without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set. -
maxPerStageDescriptorUpdateAfterBindStorageBuffersis similar tomaxPerStageDescriptorStorageBuffersbut counts descriptors from descriptor sets created with or without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set. -
maxPerStageDescriptorUpdateAfterBindSampledImagesis similar tomaxPerStageDescriptorSampledImagesbut counts descriptors from descriptor sets created with or without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set. -
maxPerStageDescriptorUpdateAfterBindStorageImagesis similar tomaxPerStageDescriptorStorageImagesbut counts descriptors from descriptor sets created with or without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set. -
maxPerStageDescriptorUpdateAfterBindInputAttachmentsis similar tomaxPerStageDescriptorInputAttachmentsbut counts descriptors from descriptor sets created with or without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set. -
maxPerStageUpdateAfterBindResourcesis similar tomaxPerStageResourcesbut counts descriptors from descriptor sets created with or without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set. -
maxDescriptorSetUpdateAfterBindSamplersis similar tomaxDescriptorSetSamplersbut counts descriptors from descriptor sets created with or without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set. -
maxDescriptorSetUpdateAfterBindUniformBuffersis similar tomaxDescriptorSetUniformBuffersbut counts descriptors from descriptor sets created with or without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set. -
maxDescriptorSetUpdateAfterBindUniformBuffersDynamicis similar tomaxDescriptorSetUniformBuffersDynamicbut counts descriptors from descriptor sets created with or without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set. -
maxDescriptorSetUpdateAfterBindStorageBuffersis similar tomaxDescriptorSetStorageBuffersbut counts descriptors from descriptor sets created with or without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set. -
maxDescriptorSetUpdateAfterBindStorageBuffersDynamicis similar tomaxDescriptorSetStorageBuffersDynamicbut counts descriptors from descriptor sets created with or without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set. -
maxDescriptorSetUpdateAfterBindSampledImagesis similar tomaxDescriptorSetSampledImagesbut counts descriptors from descriptor sets created with or without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set. -
maxDescriptorSetUpdateAfterBindStorageImagesis similar tomaxDescriptorSetStorageImagesbut counts descriptors from descriptor sets created with or without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set. -
maxDescriptorSetUpdateAfterBindInputAttachmentsis similar tomaxDescriptorSetInputAttachmentsbut counts descriptors from descriptor sets created with or without theVK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXTbit set.
If the VkPhysicalDeviceDescriptorIndexingPropertiesEXT structure is
included in the pNext chain of VkPhysicalDeviceProperties2KHR,
it is filled with the implementation-dependent limits.
The VkPhysicalDeviceConservativeRasterizationPropertiesEXT structure
is defined as:
typedef struct VkPhysicalDeviceConservativeRasterizationPropertiesEXT {
VkStructureType sType;
void* pNext;
float primitiveOverestimationSize;
float maxExtraPrimitiveOverestimationSize;
float extraPrimitiveOverestimationSizeGranularity;
VkBool32 primitiveUnderestimation;
VkBool32 conservativePointAndLineRasterization;
VkBool32 degenerateTrianglesRasterized;
VkBool32 degenerateLinesRasterized;
VkBool32 fullyCoveredFragmentShaderInputVariable;
VkBool32 conservativeRasterizationPostDepthCoverage;
} VkPhysicalDeviceConservativeRasterizationPropertiesEXT;
The members of the
VkPhysicalDeviceConservativeRasterizationPropertiesEXT structure
describe the following implementation-dependent limits:
-
primitiveOverestimationSizeis the size in pixels the generating primitive is increased at each of its edges during conservative rasterization overestimation mode. Even with a size of 0.0, conservative rasterization overestimation rules still apply and if any part of the pixel rectangle is covered by the generating primitive, fragments are generated for the entire pixel. However implementations may make the pixel coverage area even more conservative by increasing the size of the generating primitive. -
maxExtraPrimitiveOverestimationSizeis the maximum size in pixels of extra overestimation the implementation supports in the pipeline state. A value of 0.0 means the implementation does not support any additional overestimation of the generating primitive during conservative rasterization. A value above 0.0 allows the application to further increase the size of the generating primitive during conservative rasterization overestimation. -
extraPrimitiveOverestimationSizeGranularityis the granularity of extra overestimation that can be specified in the pipeline state between 0.0 andmaxExtraPrimitiveOverestimationSizeinclusive. A value of 0.0 means the implementation can use the smallest representable non-zero value in the screen space pixel fixed-point grid. -
primitiveUnderestimationis true if the implementation supports theVK_CONSERVATIVE_RASTERIZATION_MODE_UNDERESTIMATE_EXTconservative rasterization mode in addition toVK_CONSERVATIVE_RASTERIZATION_MODE_OVERESTIMATE_EXT. Otherwise the implementation only supportsVK_CONSERVATIVE_RASTERIZATION_MODE_OVERESTIMATE_EXT. -
conservativePointAndLineRasterizationis true if the implementation supports conservative rasterization of point and line primitives as well as triangle primitives. Otherwise the implementation only supports triangle primitives. -
degenerateTrianglesRasterizedis false if the implementation culls primitives generated from triangles that become zero area after they are quantized to the fixed-point rasterization pixel grid.degenerateTrianglesRasterizedis true if these primitives are not culled and the provoking vertex attributes and depth value are used for the fragments. The primitive area calculation is done on the primitive generated from the clipped triangle if applicable. Zero area primitives are backfacing and the application can enable backface culling if desired. -
degenerateLinesRasterizedis false if the implementation culls lines that become zero length after they are quantized to the fixed-point rasterization pixel grid.degenerateLinesRasterizedis true if zero length lines are not culled and the provoking vertex attributes and depth value are used for the fragments. -
fullyCoveredFragmentShaderInputVariableis true if the implementation supports the SPIR-V builtin fragment shader input variable FullyCoveredEXT which specifies that conservative rasterization is enabled and the fragment pixel square is fully covered by the generating primitive. -
conservativeRasterizationPostDepthCoverageis true if the implementation supports conservative rasterization with thePostDepthCoverageexecution mode enabled. When supported theSampleMaskbuilt-in input variable will reflect the coverage after the early per-fragment depth and stencil tests are applied even when conservative rasterization is enabled. OtherwisePostDepthCoverageexecution mode must not be used when conservative rasterization is enabled.
If the VkPhysicalDeviceConservativeRasterizationPropertiesEXT
structure is included in the pNext chain of
VkPhysicalDeviceProperties2KHR, it is filled with the
implementation-dependent limits and properties.
The VkPhysicalDeviceShaderCorePropertiesAMD structure is defined as:
typedef struct VkPhysicalDeviceShaderCorePropertiesAMD {
VkStructureType sType;
void* pNext;
uint32_t shaderEngineCount;
uint32_t shaderArraysPerEngineCount;
uint32_t computeUnitsPerShaderArray;
uint32_t simdPerComputeUnit;
uint32_t wavefrontsPerSimd;
uint32_t wavefrontSize;
uint32_t sgprsPerSimd;
uint32_t minSgprAllocation;
uint32_t maxSgprAllocation;
uint32_t sgprAllocationGranularity;
uint32_t vgprsPerSimd;
uint32_t minVgprAllocation;
uint32_t maxVgprAllocation;
uint32_t vgprAllocationGranularity;
} VkPhysicalDeviceShaderCorePropertiesAMD;
The members of the VkPhysicalDeviceShaderCorePropertiesAMD structure
describe the following implementation-dependent limits:
-
shaderEngineCountis an unsigned integer value indicating the number of shader engines found inside the shader core of the physical device. -
shaderArraysPerEngineCountis an unsigned integer value indicating the number of shader arrays inside a shader engine. Each shader array has its own scan converter, set of compute units, and a render back end (color and depth buffers). Shader arrays within a shader engine share shader processor input (wave launcher) and shader export (export buffer) units. Currently, a shader engine can have one or two shader arrays. -
computeUnitsPerShaderArrayis an unsigned integer value indicating the number of compute units within a shader array. A compute unit houses a set of SIMDs along with a sequencer module and a local data store. -
simdPerComputeUnitis an unsigned integer value indicating the number of SIMDs inside a compute unit. Each SIMD processes a single instruction at a time. -
wavefrontSizeis an unsigned integer value indicating the number of channels (or threads) in a wavefront. -
sgprsPerSimdis an unsigned integer value indicating the number of physical Scalar General Purpose Registers (SGPRs) per SIMD. -
minSgprAllocationis an unsigned integer value indicating the minimum number of SGPRs allocated for a wave. -
maxSgprAllocationis an unsigned integer value indicating the maximum number of SGPRs allocated for a wave. -
sgprAllocationGranularityis an unsigned integer value indicating the granularity of SGPR allocation for a wave. -
vgprsPerSimdis an unsigned integer value indicating the number of physical Vector General Purpose Registers (VGPRs) per SIMD. -
minVgprAllocationis an unsigned integer value indicating the minimum number of VGPRs allocated for a wave. -
maxVgprAllocationis an unsigned integer value indicating the maximum number of VGPRs allocated for a wave. -
vgprAllocationGranularityis an unsigned integer value indicating the granularity of VGPR allocation for a wave.
If the VkPhysicalDeviceShaderCorePropertiesAMD structure is included
in the pNext chain of VkPhysicalDeviceProperties2, it is filled
with the implementation-dependent limits.
32.2.1. Limit Requirements
The following table specifies the required minimum/maximum for all Vulkan graphics implementations. Where a limit corresponds to a fine-grained device feature which is optional, the feature name is listed with two required limits, one when the feature is supported and one when it is not supported. If an implementation supports a feature, the limits reported are the same whether or not the feature is enabled.
| Type | Limit | Feature |
|---|---|---|
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
sparseBinding |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
- |
|
|
- |
|
|
|
|
|
- |
|
|
- |
3 × |
|
- |
|
|
- |
3 × |
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
|
|
|
|
|
|
- |
|
|
|
|
|
|
2 × |
|
- |
2 × |
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
- |
|
|
- |
|
|
- |
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
|
- |
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
|
|
|
|
- |
|
|
- |
|
|
- |
|
|
|
|
|
|
|
|
|
|
|
- |
2 × |
|
|
2 × |
|
|
|
|
|
|
|
|
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
- |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Limit | Unsupported Limit | Supported Limit | Limit Type1 |
|---|---|---|---|
|
- |
4096 |
min |
|
- |
4096 |
min |
|
- |
256 |
min |
|
- |
4096 |
min |
|
- |
256 |
min |
|
- |
65536 |
min |
|
- |
16384 |
min |
|
- |
227 |
min |
|
- |
128 |
min |
|
- |
4096 |
min |
|
- |
4000 |
min |
|
- |
131072 |
max |
|
0 |
231 |
min |
|
- |
4 |
min |
|
- |
16 |
min |
|
- |
12 |
min |
|
- |
4 |
min |
|
- |
16 |
min |
|
- |
4 |
min |
|
- |
4 |
min |
|
- |
128 2 |
min |
|
- |
96 8 |
min, n × PerStage |
|
- |
72 8 |
min, n × PerStage |
|
- |
8 |
min |
|
- |
24 8 |
min, n × PerStage |
|
- |
4 |
min |
|
- |
96 8 |
min, n × PerStage |
|
- |
24 8 |
min, n × PerStage |
|
- |
4 |
min |
|
- |
16 |
min |
|
- |
16 |
min |
|
- |
2047 |
min |
|
- |
2048 |
min |
|
- |
64 |
min |
|
0 |
64 |
min |
|
0 |
32 |
min |
|
0 |
64 |
min |
|
0 |
64 |
min |
|
0 |
120 |
min |
|
0 |
2048 |
min |
|
0 |
64 |
min |
|
0 |
64 |
min |
|
0 |
32 |
min |
|
0 |
64 |
min |
|
0 |
64 |
min |
|
0 |
256 |
min |
|
0 |
1024 |
min |
|
- |
64 |
min |
|
- |
4 |
min |
|
0 |
1 |
min |
|
- |
4 |
min |
|
- |
16384 |
min |
|
- |
(65535,65535,65535) |
min |
|
- |
128 |
min |
|
- |
(128,128,64) |
min |
|
- |
4 |
min |
|
- |
4 |
min |
|
- |
4 |
min |
|
224-1 |
232-1 |
min |
|
1 |
216-1 |
min |
|
- |
2 |
min |
|
1 |
16 |
min |
|
1 |
16 |
min |
|
- |
(4096,4096) 3 |
min |
|
- |
(-8192,8191) 4 |
(max,min) |
|
- |
0 |
min |
|
- |
64 |
min |
|
- |
256 |
max |
|
- |
256 |
max |
|
- |
256 |
max |
|
- |
-8 |
max |
|
- |
7 |
min |
|
0 |
-8 |
max |
|
0 |
7 |
min |
|
0.0 |
-0.5 5 |
max |
|
0.0 |
0.5 - (1 ULP) 5 |
min |
|
0 |
4 5 |
min |
|
- |
4096 |
min |
|
- |
4096 |
min |
|
- |
256 |
min |
|
- |
( |
min |
|
- |
( |
min |
|
- |
( |
min |
|
- |
( |
min |
|
- |
4 |
min |
|
- |
( |
min |
|
- |
|
min |
|
- |
( |
min |
|
- |
( |
min |
|
|
( |
min |
|
- |
1 |
min |
|
- |
- |
implementation dependent |
|
- |
- |
duration |
|
0 |
8 |
min |
|
0 |
8 |
min |
|
0 |
8 |
min |
|
- |
2 |
min |
|
(1.0,1.0) |
(1.0,64.0 - ULP)6 |
(max,min) |
|
(1.0,1.0) |
(1.0,8.0 - ULP)7 |
(max,min) |
|
0.0 |
1.0 6 |
max, fixed point increment |
|
0.0 |
1.0 7 |
max, fixed point increment |
|
- |
- |
implementation dependent |
|
- |
- |
implementation dependent |
|
- |
- |
recommendation |
|
- |
- |
recommendation |
|
- |
256 |
max |
|
- |
32 |
min |
|
- |
6 |
min |
|
- |
227-1 |
min |
|
0 |
4 |
min |
|
- |
|
min |
|
- |
(1,1) |
min |
|
- |
(0.0, 0.9375) |
(max,min) |
|
- |
4 |
min |
|
- |
false |
implementation dependent |
|
- |
65536 |
max |
|
- |
- |
implementation dependent |
|
- |
- |
implementation dependent |
|
- |
- |
implementation dependent |
|
- |
1 |
min |
|
- |
false |
implementation dependent |
|
- |
false |
implementation dependent |
|
- |
false |
implementation dependent |
|
- |
false |
implementation dependent |
|
- |
false |
implementation dependent |
|
- |
1024 |
min |
|
- |
230 |
min |
|
- |
0.0 |
min |
|
- |
0.0 |
min |
|
- |
0.0 |
min |
|
- |
false |
implementation dependent |
|
- |
false |
implementation dependent |
|
- |
false |
implementation dependent |
|
- |
false |
implementation dependent |
|
- |
false |
implementation dependent |
|
- |
false |
implementation dependent |
|
- |
500000 |
min |
|
- |
false |
implementation dependent |
|
- |
false |
implementation dependent |
|
- |
false |
implementation dependent |
|
- |
false |
implementation dependent |
|
- |
false |
implementation dependent |
|
- |
500000 9 |
min |
|
- |
12 9 |
min |
|
- |
500000 9 |
min |
|
- |
500000 9 |
min |
|
- |
500000 9 |
min |
|
- |
500000 9 |
min |
|
- |
500000 9 |
min |
|
- |
500000 9 |
min |
|
- |
96 8 9 |
min, n × PerStage |
|
- |
8 9 |
min |
|
- |
500000 9 |
min |
|
- |
4 9 |
min |
|
- |
500000 9 |
min |
|
- |
500000 9 |
min |
|
- |
500000 9 |
min |
|
- |
216-1 |
min |
- 1
-
The Limit Type column specifies the limit is either the minimum limit all implementations must support or the maximum limit all implementations must support. For bitmasks a minimum limit is the least bits all implementations must set, but they may have additional bits set beyond this minimum.
- 2
-
The
maxPerStageResourcesmust be at least the smallest of the following:-
the sum of the
maxPerStageDescriptorUniformBuffers,maxPerStageDescriptorStorageBuffers,maxPerStageDescriptorSampledImages,maxPerStageDescriptorStorageImages,maxPerStageDescriptorInputAttachments,maxColorAttachmentslimits, or -
128.
It may not be possible to reach this limit in every stage.
-
- 3
-
See
maxViewportDimensionsfor the required relationship to other limits. - 4
-
See
viewportBoundsRangefor the required relationship to other limits. - 5
-
The values
minInterpolationOffsetandmaxInterpolationOffsetdescribe the closed interval of supported interpolation offsets: [minInterpolationOffset,maxInterpolationOffset]. The ULP is determined bysubPixelInterpolationOffsetBits. IfsubPixelInterpolationOffsetBitsis 4, this provides increments of (1/24) = 0.0625, and thus the range of supported interpolation offsets would be [-0.5, 0.4375]. - 6
-
The point size ULP is determined by
pointSizeGranularity. If thepointSizeGranularityis 0.125, the range of supported point sizes must be at least [1.0, 63.875]. - 7
-
The line width ULP is determined by
lineWidthGranularity. If thelineWidthGranularityis 0.0625, the range of supported line widths must be at least [1.0, 7.9375]. - 8
-
The minimum
maxDescriptorSet*limit is n times the corresponding specification minimummaxPerStageDescriptor*limit, where n is the number of shader stages supported by the VkPhysicalDevice. If all shader stages are supported, n = 6 (vertex, tessellation control, tessellation evaluation, geometry, fragment, compute). - 9
-
The
UpdateAfterBinddescriptor limits must each be greater than or equal to the correspondingnon-UpdateAfterBind limit.
32.3. Additional Multisampling Capabilities
In addition to the minimum capabilities described in the previous section (Limits), implementations may support additional multisampling capabilities specific to a particular sample count.
To query additional sample count specific multisampling capabilities, call:
void vkGetPhysicalDeviceMultisamplePropertiesEXT(
VkPhysicalDevice physicalDevice,
VkSampleCountFlagBits samples,
VkMultisamplePropertiesEXT* pMultisampleProperties);
-
physicalDeviceis the physical device from which to query the additional multisampling capabilities. -
samplesis the sample count to query the capabilities for. -
pMultisamplePropertiesis a pointer to a structure of type VkMultisamplePropertiesEXT, in which information about the additional multisampling capabilities specific to the sample count is returned.
The VkMultisamplePropertiesEXT structure is defined as
typedef struct VkMultisamplePropertiesEXT {
VkStructureType sType;
void* pNext;
VkExtent2D maxSampleLocationGridSize;
} VkMultisamplePropertiesEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
maxSampleLocationGridSizeis the maximum size of the pixel grid in which sample locations can vary.
If the sample count for which additional multisampling capabilities are
requested using vkGetPhysicalDeviceMultisamplePropertiesEXT is set
in VkPhysicalDeviceSampleLocationsEXT::
sampleLocationSampleCounts the width and height members
of VkMultisamplePropertiesEXT::maxSampleLocationGridSize must
be greater than or equal to the corresponding members of
VkPhysicalDeviceSampleLocationsEXT::
maxSampleLocationGridSize,
respectively, otherwise both members must be 0.
32.4. Formats
The features for the set of formats (VkFormat) supported by the implementation are queried individually using the vkGetPhysicalDeviceFormatProperties command.
32.4.1. Format Definition
Image formats which can be passed to, and may be returned from Vulkan commands, are:
typedef enum VkFormat {
VK_FORMAT_UNDEFINED = 0,
VK_FORMAT_R4G4_UNORM_PACK8 = 1,
VK_FORMAT_R4G4B4A4_UNORM_PACK16 = 2,
VK_FORMAT_B4G4R4A4_UNORM_PACK16 = 3,
VK_FORMAT_R5G6B5_UNORM_PACK16 = 4,
VK_FORMAT_B5G6R5_UNORM_PACK16 = 5,
VK_FORMAT_R5G5B5A1_UNORM_PACK16 = 6,
VK_FORMAT_B5G5R5A1_UNORM_PACK16 = 7,
VK_FORMAT_A1R5G5B5_UNORM_PACK16 = 8,
VK_FORMAT_R8_UNORM = 9,
VK_FORMAT_R8_SNORM = 10,
VK_FORMAT_R8_USCALED = 11,
VK_FORMAT_R8_SSCALED = 12,
VK_FORMAT_R8_UINT = 13,
VK_FORMAT_R8_SINT = 14,
VK_FORMAT_R8_SRGB = 15,
VK_FORMAT_R8G8_UNORM = 16,
VK_FORMAT_R8G8_SNORM = 17,
VK_FORMAT_R8G8_USCALED = 18,
VK_FORMAT_R8G8_SSCALED = 19,
VK_FORMAT_R8G8_UINT = 20,
VK_FORMAT_R8G8_SINT = 21,
VK_FORMAT_R8G8_SRGB = 22,
VK_FORMAT_R8G8B8_UNORM = 23,
VK_FORMAT_R8G8B8_SNORM = 24,
VK_FORMAT_R8G8B8_USCALED = 25,
VK_FORMAT_R8G8B8_SSCALED = 26,
VK_FORMAT_R8G8B8_UINT = 27,
VK_FORMAT_R8G8B8_SINT = 28,
VK_FORMAT_R8G8B8_SRGB = 29,
VK_FORMAT_B8G8R8_UNORM = 30,
VK_FORMAT_B8G8R8_SNORM = 31,
VK_FORMAT_B8G8R8_USCALED = 32,
VK_FORMAT_B8G8R8_SSCALED = 33,
VK_FORMAT_B8G8R8_UINT = 34,
VK_FORMAT_B8G8R8_SINT = 35,
VK_FORMAT_B8G8R8_SRGB = 36,
VK_FORMAT_R8G8B8A8_UNORM = 37,
VK_FORMAT_R8G8B8A8_SNORM = 38,
VK_FORMAT_R8G8B8A8_USCALED = 39,
VK_FORMAT_R8G8B8A8_SSCALED = 40,
VK_FORMAT_R8G8B8A8_UINT = 41,
VK_FORMAT_R8G8B8A8_SINT = 42,
VK_FORMAT_R8G8B8A8_SRGB = 43,
VK_FORMAT_B8G8R8A8_UNORM = 44,
VK_FORMAT_B8G8R8A8_SNORM = 45,
VK_FORMAT_B8G8R8A8_USCALED = 46,
VK_FORMAT_B8G8R8A8_SSCALED = 47,
VK_FORMAT_B8G8R8A8_UINT = 48,
VK_FORMAT_B8G8R8A8_SINT = 49,
VK_FORMAT_B8G8R8A8_SRGB = 50,
VK_FORMAT_A8B8G8R8_UNORM_PACK32 = 51,
VK_FORMAT_A8B8G8R8_SNORM_PACK32 = 52,
VK_FORMAT_A8B8G8R8_USCALED_PACK32 = 53,
VK_FORMAT_A8B8G8R8_SSCALED_PACK32 = 54,
VK_FORMAT_A8B8G8R8_UINT_PACK32 = 55,
VK_FORMAT_A8B8G8R8_SINT_PACK32 = 56,
VK_FORMAT_A8B8G8R8_SRGB_PACK32 = 57,
VK_FORMAT_A2R10G10B10_UNORM_PACK32 = 58,
VK_FORMAT_A2R10G10B10_SNORM_PACK32 = 59,
VK_FORMAT_A2R10G10B10_USCALED_PACK32 = 60,
VK_FORMAT_A2R10G10B10_SSCALED_PACK32 = 61,
VK_FORMAT_A2R10G10B10_UINT_PACK32 = 62,
VK_FORMAT_A2R10G10B10_SINT_PACK32 = 63,
VK_FORMAT_A2B10G10R10_UNORM_PACK32 = 64,
VK_FORMAT_A2B10G10R10_SNORM_PACK32 = 65,
VK_FORMAT_A2B10G10R10_USCALED_PACK32 = 66,
VK_FORMAT_A2B10G10R10_SSCALED_PACK32 = 67,
VK_FORMAT_A2B10G10R10_UINT_PACK32 = 68,
VK_FORMAT_A2B10G10R10_SINT_PACK32 = 69,
VK_FORMAT_R16_UNORM = 70,
VK_FORMAT_R16_SNORM = 71,
VK_FORMAT_R16_USCALED = 72,
VK_FORMAT_R16_SSCALED = 73,
VK_FORMAT_R16_UINT = 74,
VK_FORMAT_R16_SINT = 75,
VK_FORMAT_R16_SFLOAT = 76,
VK_FORMAT_R16G16_UNORM = 77,
VK_FORMAT_R16G16_SNORM = 78,
VK_FORMAT_R16G16_USCALED = 79,
VK_FORMAT_R16G16_SSCALED = 80,
VK_FORMAT_R16G16_UINT = 81,
VK_FORMAT_R16G16_SINT = 82,
VK_FORMAT_R16G16_SFLOAT = 83,
VK_FORMAT_R16G16B16_UNORM = 84,
VK_FORMAT_R16G16B16_SNORM = 85,
VK_FORMAT_R16G16B16_USCALED = 86,
VK_FORMAT_R16G16B16_SSCALED = 87,
VK_FORMAT_R16G16B16_UINT = 88,
VK_FORMAT_R16G16B16_SINT = 89,
VK_FORMAT_R16G16B16_SFLOAT = 90,
VK_FORMAT_R16G16B16A16_UNORM = 91,
VK_FORMAT_R16G16B16A16_SNORM = 92,
VK_FORMAT_R16G16B16A16_USCALED = 93,
VK_FORMAT_R16G16B16A16_SSCALED = 94,
VK_FORMAT_R16G16B16A16_UINT = 95,
VK_FORMAT_R16G16B16A16_SINT = 96,
VK_FORMAT_R16G16B16A16_SFLOAT = 97,
VK_FORMAT_R32_UINT = 98,
VK_FORMAT_R32_SINT = 99,
VK_FORMAT_R32_SFLOAT = 100,
VK_FORMAT_R32G32_UINT = 101,
VK_FORMAT_R32G32_SINT = 102,
VK_FORMAT_R32G32_SFLOAT = 103,
VK_FORMAT_R32G32B32_UINT = 104,
VK_FORMAT_R32G32B32_SINT = 105,
VK_FORMAT_R32G32B32_SFLOAT = 106,
VK_FORMAT_R32G32B32A32_UINT = 107,
VK_FORMAT_R32G32B32A32_SINT = 108,
VK_FORMAT_R32G32B32A32_SFLOAT = 109,
VK_FORMAT_R64_UINT = 110,
VK_FORMAT_R64_SINT = 111,
VK_FORMAT_R64_SFLOAT = 112,
VK_FORMAT_R64G64_UINT = 113,
VK_FORMAT_R64G64_SINT = 114,
VK_FORMAT_R64G64_SFLOAT = 115,
VK_FORMAT_R64G64B64_UINT = 116,
VK_FORMAT_R64G64B64_SINT = 117,
VK_FORMAT_R64G64B64_SFLOAT = 118,
VK_FORMAT_R64G64B64A64_UINT = 119,
VK_FORMAT_R64G64B64A64_SINT = 120,
VK_FORMAT_R64G64B64A64_SFLOAT = 121,
VK_FORMAT_B10G11R11_UFLOAT_PACK32 = 122,
VK_FORMAT_E5B9G9R9_UFLOAT_PACK32 = 123,
VK_FORMAT_D16_UNORM = 124,
VK_FORMAT_X8_D24_UNORM_PACK32 = 125,
VK_FORMAT_D32_SFLOAT = 126,
VK_FORMAT_S8_UINT = 127,
VK_FORMAT_D16_UNORM_S8_UINT = 128,
VK_FORMAT_D24_UNORM_S8_UINT = 129,
VK_FORMAT_D32_SFLOAT_S8_UINT = 130,
VK_FORMAT_BC1_RGB_UNORM_BLOCK = 131,
VK_FORMAT_BC1_RGB_SRGB_BLOCK = 132,
VK_FORMAT_BC1_RGBA_UNORM_BLOCK = 133,
VK_FORMAT_BC1_RGBA_SRGB_BLOCK = 134,
VK_FORMAT_BC2_UNORM_BLOCK = 135,
VK_FORMAT_BC2_SRGB_BLOCK = 136,
VK_FORMAT_BC3_UNORM_BLOCK = 137,
VK_FORMAT_BC3_SRGB_BLOCK = 138,
VK_FORMAT_BC4_UNORM_BLOCK = 139,
VK_FORMAT_BC4_SNORM_BLOCK = 140,
VK_FORMAT_BC5_UNORM_BLOCK = 141,
VK_FORMAT_BC5_SNORM_BLOCK = 142,
VK_FORMAT_BC6H_UFLOAT_BLOCK = 143,
VK_FORMAT_BC6H_SFLOAT_BLOCK = 144,
VK_FORMAT_BC7_UNORM_BLOCK = 145,
VK_FORMAT_BC7_SRGB_BLOCK = 146,
VK_FORMAT_ETC2_R8G8B8_UNORM_BLOCK = 147,
VK_FORMAT_ETC2_R8G8B8_SRGB_BLOCK = 148,
VK_FORMAT_ETC2_R8G8B8A1_UNORM_BLOCK = 149,
VK_FORMAT_ETC2_R8G8B8A1_SRGB_BLOCK = 150,
VK_FORMAT_ETC2_R8G8B8A8_UNORM_BLOCK = 151,
VK_FORMAT_ETC2_R8G8B8A8_SRGB_BLOCK = 152,
VK_FORMAT_EAC_R11_UNORM_BLOCK = 153,
VK_FORMAT_EAC_R11_SNORM_BLOCK = 154,
VK_FORMAT_EAC_R11G11_UNORM_BLOCK = 155,
VK_FORMAT_EAC_R11G11_SNORM_BLOCK = 156,
VK_FORMAT_ASTC_4x4_UNORM_BLOCK = 157,
VK_FORMAT_ASTC_4x4_SRGB_BLOCK = 158,
VK_FORMAT_ASTC_5x4_UNORM_BLOCK = 159,
VK_FORMAT_ASTC_5x4_SRGB_BLOCK = 160,
VK_FORMAT_ASTC_5x5_UNORM_BLOCK = 161,
VK_FORMAT_ASTC_5x5_SRGB_BLOCK = 162,
VK_FORMAT_ASTC_6x5_UNORM_BLOCK = 163,
VK_FORMAT_ASTC_6x5_SRGB_BLOCK = 164,
VK_FORMAT_ASTC_6x6_UNORM_BLOCK = 165,
VK_FORMAT_ASTC_6x6_SRGB_BLOCK = 166,
VK_FORMAT_ASTC_8x5_UNORM_BLOCK = 167,
VK_FORMAT_ASTC_8x5_SRGB_BLOCK = 168,
VK_FORMAT_ASTC_8x6_UNORM_BLOCK = 169,
VK_FORMAT_ASTC_8x6_SRGB_BLOCK = 170,
VK_FORMAT_ASTC_8x8_UNORM_BLOCK = 171,
VK_FORMAT_ASTC_8x8_SRGB_BLOCK = 172,
VK_FORMAT_ASTC_10x5_UNORM_BLOCK = 173,
VK_FORMAT_ASTC_10x5_SRGB_BLOCK = 174,
VK_FORMAT_ASTC_10x6_UNORM_BLOCK = 175,
VK_FORMAT_ASTC_10x6_SRGB_BLOCK = 176,
VK_FORMAT_ASTC_10x8_UNORM_BLOCK = 177,
VK_FORMAT_ASTC_10x8_SRGB_BLOCK = 178,
VK_FORMAT_ASTC_10x10_UNORM_BLOCK = 179,
VK_FORMAT_ASTC_10x10_SRGB_BLOCK = 180,
VK_FORMAT_ASTC_12x10_UNORM_BLOCK = 181,
VK_FORMAT_ASTC_12x10_SRGB_BLOCK = 182,
VK_FORMAT_ASTC_12x12_UNORM_BLOCK = 183,
VK_FORMAT_ASTC_12x12_SRGB_BLOCK = 184,
VK_FORMAT_G8B8G8R8_422_UNORM = 1000156000,
VK_FORMAT_B8G8R8G8_422_UNORM = 1000156001,
VK_FORMAT_G8_B8_R8_3PLANE_420_UNORM = 1000156002,
VK_FORMAT_G8_B8R8_2PLANE_420_UNORM = 1000156003,
VK_FORMAT_G8_B8_R8_3PLANE_422_UNORM = 1000156004,
VK_FORMAT_G8_B8R8_2PLANE_422_UNORM = 1000156005,
VK_FORMAT_G8_B8_R8_3PLANE_444_UNORM = 1000156006,
VK_FORMAT_R10X6_UNORM_PACK16 = 1000156007,
VK_FORMAT_R10X6G10X6_UNORM_2PACK16 = 1000156008,
VK_FORMAT_R10X6G10X6B10X6A10X6_UNORM_4PACK16 = 1000156009,
VK_FORMAT_G10X6B10X6G10X6R10X6_422_UNORM_4PACK16 = 1000156010,
VK_FORMAT_B10X6G10X6R10X6G10X6_422_UNORM_4PACK16 = 1000156011,
VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_420_UNORM_3PACK16 = 1000156012,
VK_FORMAT_G10X6_B10X6R10X6_2PLANE_420_UNORM_3PACK16 = 1000156013,
VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_422_UNORM_3PACK16 = 1000156014,
VK_FORMAT_G10X6_B10X6R10X6_2PLANE_422_UNORM_3PACK16 = 1000156015,
VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_444_UNORM_3PACK16 = 1000156016,
VK_FORMAT_R12X4_UNORM_PACK16 = 1000156017,
VK_FORMAT_R12X4G12X4_UNORM_2PACK16 = 1000156018,
VK_FORMAT_R12X4G12X4B12X4A12X4_UNORM_4PACK16 = 1000156019,
VK_FORMAT_G12X4B12X4G12X4R12X4_422_UNORM_4PACK16 = 1000156020,
VK_FORMAT_B12X4G12X4R12X4G12X4_422_UNORM_4PACK16 = 1000156021,
VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_420_UNORM_3PACK16 = 1000156022,
VK_FORMAT_G12X4_B12X4R12X4_2PLANE_420_UNORM_3PACK16 = 1000156023,
VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_422_UNORM_3PACK16 = 1000156024,
VK_FORMAT_G12X4_B12X4R12X4_2PLANE_422_UNORM_3PACK16 = 1000156025,
VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_444_UNORM_3PACK16 = 1000156026,
VK_FORMAT_G16B16G16R16_422_UNORM = 1000156027,
VK_FORMAT_B16G16R16G16_422_UNORM = 1000156028,
VK_FORMAT_G16_B16_R16_3PLANE_420_UNORM = 1000156029,
VK_FORMAT_G16_B16R16_2PLANE_420_UNORM = 1000156030,
VK_FORMAT_G16_B16_R16_3PLANE_422_UNORM = 1000156031,
VK_FORMAT_G16_B16R16_2PLANE_422_UNORM = 1000156032,
VK_FORMAT_G16_B16_R16_3PLANE_444_UNORM = 1000156033,
VK_FORMAT_PVRTC1_2BPP_UNORM_BLOCK_IMG = 1000054000,
VK_FORMAT_PVRTC1_4BPP_UNORM_BLOCK_IMG = 1000054001,
VK_FORMAT_PVRTC2_2BPP_UNORM_BLOCK_IMG = 1000054002,
VK_FORMAT_PVRTC2_4BPP_UNORM_BLOCK_IMG = 1000054003,
VK_FORMAT_PVRTC1_2BPP_SRGB_BLOCK_IMG = 1000054004,
VK_FORMAT_PVRTC1_4BPP_SRGB_BLOCK_IMG = 1000054005,
VK_FORMAT_PVRTC2_2BPP_SRGB_BLOCK_IMG = 1000054006,
VK_FORMAT_PVRTC2_4BPP_SRGB_BLOCK_IMG = 1000054007,
VK_FORMAT_G8B8G8R8_422_UNORM_KHR = VK_FORMAT_G8B8G8R8_422_UNORM,
VK_FORMAT_B8G8R8G8_422_UNORM_KHR = VK_FORMAT_B8G8R8G8_422_UNORM,
VK_FORMAT_G8_B8_R8_3PLANE_420_UNORM_KHR = VK_FORMAT_G8_B8_R8_3PLANE_420_UNORM,
VK_FORMAT_G8_B8R8_2PLANE_420_UNORM_KHR = VK_FORMAT_G8_B8R8_2PLANE_420_UNORM,
VK_FORMAT_G8_B8_R8_3PLANE_422_UNORM_KHR = VK_FORMAT_G8_B8_R8_3PLANE_422_UNORM,
VK_FORMAT_G8_B8R8_2PLANE_422_UNORM_KHR = VK_FORMAT_G8_B8R8_2PLANE_422_UNORM,
VK_FORMAT_G8_B8_R8_3PLANE_444_UNORM_KHR = VK_FORMAT_G8_B8_R8_3PLANE_444_UNORM,
VK_FORMAT_R10X6_UNORM_PACK16_KHR = VK_FORMAT_R10X6_UNORM_PACK16,
VK_FORMAT_R10X6G10X6_UNORM_2PACK16_KHR = VK_FORMAT_R10X6G10X6_UNORM_2PACK16,
VK_FORMAT_R10X6G10X6B10X6A10X6_UNORM_4PACK16_KHR = VK_FORMAT_R10X6G10X6B10X6A10X6_UNORM_4PACK16,
VK_FORMAT_G10X6B10X6G10X6R10X6_422_UNORM_4PACK16_KHR = VK_FORMAT_G10X6B10X6G10X6R10X6_422_UNORM_4PACK16,
VK_FORMAT_B10X6G10X6R10X6G10X6_422_UNORM_4PACK16_KHR = VK_FORMAT_B10X6G10X6R10X6G10X6_422_UNORM_4PACK16,
VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_420_UNORM_3PACK16_KHR = VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_420_UNORM_3PACK16,
VK_FORMAT_G10X6_B10X6R10X6_2PLANE_420_UNORM_3PACK16_KHR = VK_FORMAT_G10X6_B10X6R10X6_2PLANE_420_UNORM_3PACK16,
VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_422_UNORM_3PACK16_KHR = VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_422_UNORM_3PACK16,
VK_FORMAT_G10X6_B10X6R10X6_2PLANE_422_UNORM_3PACK16_KHR = VK_FORMAT_G10X6_B10X6R10X6_2PLANE_422_UNORM_3PACK16,
VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_444_UNORM_3PACK16_KHR = VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_444_UNORM_3PACK16,
VK_FORMAT_R12X4_UNORM_PACK16_KHR = VK_FORMAT_R12X4_UNORM_PACK16,
VK_FORMAT_R12X4G12X4_UNORM_2PACK16_KHR = VK_FORMAT_R12X4G12X4_UNORM_2PACK16,
VK_FORMAT_R12X4G12X4B12X4A12X4_UNORM_4PACK16_KHR = VK_FORMAT_R12X4G12X4B12X4A12X4_UNORM_4PACK16,
VK_FORMAT_G12X4B12X4G12X4R12X4_422_UNORM_4PACK16_KHR = VK_FORMAT_G12X4B12X4G12X4R12X4_422_UNORM_4PACK16,
VK_FORMAT_B12X4G12X4R12X4G12X4_422_UNORM_4PACK16_KHR = VK_FORMAT_B12X4G12X4R12X4G12X4_422_UNORM_4PACK16,
VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_420_UNORM_3PACK16_KHR = VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_420_UNORM_3PACK16,
VK_FORMAT_G12X4_B12X4R12X4_2PLANE_420_UNORM_3PACK16_KHR = VK_FORMAT_G12X4_B12X4R12X4_2PLANE_420_UNORM_3PACK16,
VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_422_UNORM_3PACK16_KHR = VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_422_UNORM_3PACK16,
VK_FORMAT_G12X4_B12X4R12X4_2PLANE_422_UNORM_3PACK16_KHR = VK_FORMAT_G12X4_B12X4R12X4_2PLANE_422_UNORM_3PACK16,
VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_444_UNORM_3PACK16_KHR = VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_444_UNORM_3PACK16,
VK_FORMAT_G16B16G16R16_422_UNORM_KHR = VK_FORMAT_G16B16G16R16_422_UNORM,
VK_FORMAT_B16G16R16G16_422_UNORM_KHR = VK_FORMAT_B16G16R16G16_422_UNORM,
VK_FORMAT_G16_B16_R16_3PLANE_420_UNORM_KHR = VK_FORMAT_G16_B16_R16_3PLANE_420_UNORM,
VK_FORMAT_G16_B16R16_2PLANE_420_UNORM_KHR = VK_FORMAT_G16_B16R16_2PLANE_420_UNORM,
VK_FORMAT_G16_B16_R16_3PLANE_422_UNORM_KHR = VK_FORMAT_G16_B16_R16_3PLANE_422_UNORM,
VK_FORMAT_G16_B16R16_2PLANE_422_UNORM_KHR = VK_FORMAT_G16_B16R16_2PLANE_422_UNORM,
VK_FORMAT_G16_B16_R16_3PLANE_444_UNORM_KHR = VK_FORMAT_G16_B16_R16_3PLANE_444_UNORM,
} VkFormat;
-
VK_FORMAT_UNDEFINEDspecifies that the format is not specified. -
VK_FORMAT_R4G4_UNORM_PACK8specifies a two-component, 8-bit packed unsigned normalized format that has a 4-bit R component in bits 4..7, and a 4-bit G component in bits 0..3. -
VK_FORMAT_R4G4B4A4_UNORM_PACK16specifies a four-component, 16-bit packed unsigned normalized format that has a 4-bit R component in bits 12..15, a 4-bit G component in bits 8..11, a 4-bit B component in bits 4..7, and a 4-bit A component in bits 0..3. -
VK_FORMAT_B4G4R4A4_UNORM_PACK16specifies a four-component, 16-bit packed unsigned normalized format that has a 4-bit B component in bits 12..15, a 4-bit G component in bits 8..11, a 4-bit R component in bits 4..7, and a 4-bit A component in bits 0..3. -
VK_FORMAT_R5G6B5_UNORM_PACK16specifies a three-component, 16-bit packed unsigned normalized format that has a 5-bit R component in bits 11..15, a 6-bit G component in bits 5..10, and a 5-bit B component in bits 0..4. -
VK_FORMAT_B5G6R5_UNORM_PACK16specifies a three-component, 16-bit packed unsigned normalized format that has a 5-bit B component in bits 11..15, a 6-bit G component in bits 5..10, and a 5-bit R component in bits 0..4. -
VK_FORMAT_R5G5B5A1_UNORM_PACK16specifies a four-component, 16-bit packed unsigned normalized format that has a 5-bit R component in bits 11..15, a 5-bit G component in bits 6..10, a 5-bit B component in bits 1..5, and a 1-bit A component in bit 0. -
VK_FORMAT_B5G5R5A1_UNORM_PACK16specifies a four-component, 16-bit packed unsigned normalized format that has a 5-bit B component in bits 11..15, a 5-bit G component in bits 6..10, a 5-bit R component in bits 1..5, and a 1-bit A component in bit 0. -
VK_FORMAT_A1R5G5B5_UNORM_PACK16specifies a four-component, 16-bit packed unsigned normalized format that has a 1-bit A component in bit 15, a 5-bit R component in bits 10..14, a 5-bit G component in bits 5..9, and a 5-bit B component in bits 0..4. -
VK_FORMAT_R8_UNORMspecifies a one-component, 8-bit unsigned normalized format that has a single 8-bit R component. -
VK_FORMAT_R8_SNORMspecifies a one-component, 8-bit signed normalized format that has a single 8-bit R component. -
VK_FORMAT_R8_USCALEDspecifies a one-component, 8-bit unsigned scaled integer format that has a single 8-bit R component. -
VK_FORMAT_R8_SSCALEDspecifies a one-component, 8-bit signed scaled integer format that has a single 8-bit R component. -
VK_FORMAT_R8_UINTspecifies a one-component, 8-bit unsigned integer format that has a single 8-bit R component. -
VK_FORMAT_R8_SINTspecifies a one-component, 8-bit signed integer format that has a single 8-bit R component. -
VK_FORMAT_R8_SRGBspecifies a one-component, 8-bit unsigned normalized format that has a single 8-bit R component stored with sRGB nonlinear encoding. -
VK_FORMAT_R8G8_UNORMspecifies a two-component, 16-bit unsigned normalized format that has an 8-bit R component in byte 0, and an 8-bit G component in byte 1. -
VK_FORMAT_R8G8_SNORMspecifies a two-component, 16-bit signed normalized format that has an 8-bit R component in byte 0, and an 8-bit G component in byte 1. -
VK_FORMAT_R8G8_USCALEDspecifies a two-component, 16-bit unsigned scaled integer format that has an 8-bit R component in byte 0, and an 8-bit G component in byte 1. -
VK_FORMAT_R8G8_SSCALEDspecifies a two-component, 16-bit signed scaled integer format that has an 8-bit R component in byte 0, and an 8-bit G component in byte 1. -
VK_FORMAT_R8G8_UINTspecifies a two-component, 16-bit unsigned integer format that has an 8-bit R component in byte 0, and an 8-bit G component in byte 1. -
VK_FORMAT_R8G8_SINTspecifies a two-component, 16-bit signed integer format that has an 8-bit R component in byte 0, and an 8-bit G component in byte 1. -
VK_FORMAT_R8G8_SRGBspecifies a two-component, 16-bit unsigned normalized format that has an 8-bit R component stored with sRGB nonlinear encoding in byte 0, and an 8-bit G component stored with sRGB nonlinear encoding in byte 1. -
VK_FORMAT_R8G8B8_UNORMspecifies a three-component, 24-bit unsigned normalized format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, and an 8-bit B component in byte 2. -
VK_FORMAT_R8G8B8_SNORMspecifies a three-component, 24-bit signed normalized format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, and an 8-bit B component in byte 2. -
VK_FORMAT_R8G8B8_USCALEDspecifies a three-component, 24-bit unsigned scaled format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, and an 8-bit B component in byte 2. -
VK_FORMAT_R8G8B8_SSCALEDspecifies a three-component, 24-bit signed scaled format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, and an 8-bit B component in byte 2. -
VK_FORMAT_R8G8B8_UINTspecifies a three-component, 24-bit unsigned integer format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, and an 8-bit B component in byte 2. -
VK_FORMAT_R8G8B8_SINTspecifies a three-component, 24-bit signed integer format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, and an 8-bit B component in byte 2. -
VK_FORMAT_R8G8B8_SRGBspecifies a three-component, 24-bit unsigned normalized format that has an 8-bit R component stored with sRGB nonlinear encoding in byte 0, an 8-bit G component stored with sRGB nonlinear encoding in byte 1, and an 8-bit B component stored with sRGB nonlinear encoding in byte 2. -
VK_FORMAT_B8G8R8_UNORMspecifies a three-component, 24-bit unsigned normalized format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, and an 8-bit R component in byte 2. -
VK_FORMAT_B8G8R8_SNORMspecifies a three-component, 24-bit signed normalized format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, and an 8-bit R component in byte 2. -
VK_FORMAT_B8G8R8_USCALEDspecifies a three-component, 24-bit unsigned scaled format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, and an 8-bit R component in byte 2. -
VK_FORMAT_B8G8R8_SSCALEDspecifies a three-component, 24-bit signed scaled format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, and an 8-bit R component in byte 2. -
VK_FORMAT_B8G8R8_UINTspecifies a three-component, 24-bit unsigned integer format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, and an 8-bit R component in byte 2. -
VK_FORMAT_B8G8R8_SINTspecifies a three-component, 24-bit signed integer format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, and an 8-bit R component in byte 2. -
VK_FORMAT_B8G8R8_SRGBspecifies a three-component, 24-bit unsigned normalized format that has an 8-bit B component stored with sRGB nonlinear encoding in byte 0, an 8-bit G component stored with sRGB nonlinear encoding in byte 1, and an 8-bit R component stored with sRGB nonlinear encoding in byte 2. -
VK_FORMAT_R8G8B8A8_UNORMspecifies a four-component, 32-bit unsigned normalized format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, an 8-bit B component in byte 2, and an 8-bit A component in byte 3. -
VK_FORMAT_R8G8B8A8_SNORMspecifies a four-component, 32-bit signed normalized format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, an 8-bit B component in byte 2, and an 8-bit A component in byte 3. -
VK_FORMAT_R8G8B8A8_USCALEDspecifies a four-component, 32-bit unsigned scaled format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, an 8-bit B component in byte 2, and an 8-bit A component in byte 3. -
VK_FORMAT_R8G8B8A8_SSCALEDspecifies a four-component, 32-bit signed scaled format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, an 8-bit B component in byte 2, and an 8-bit A component in byte 3. -
VK_FORMAT_R8G8B8A8_UINTspecifies a four-component, 32-bit unsigned integer format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, an 8-bit B component in byte 2, and an 8-bit A component in byte 3. -
VK_FORMAT_R8G8B8A8_SINTspecifies a four-component, 32-bit signed integer format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, an 8-bit B component in byte 2, and an 8-bit A component in byte 3. -
VK_FORMAT_R8G8B8A8_SRGBspecifies a four-component, 32-bit unsigned normalized format that has an 8-bit R component stored with sRGB nonlinear encoding in byte 0, an 8-bit G component stored with sRGB nonlinear encoding in byte 1, an 8-bit B component stored with sRGB nonlinear encoding in byte 2, and an 8-bit A component in byte 3. -
VK_FORMAT_B8G8R8A8_UNORMspecifies a four-component, 32-bit unsigned normalized format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, an 8-bit R component in byte 2, and an 8-bit A component in byte 3. -
VK_FORMAT_B8G8R8A8_SNORMspecifies a four-component, 32-bit signed normalized format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, an 8-bit R component in byte 2, and an 8-bit A component in byte 3. -
VK_FORMAT_B8G8R8A8_USCALEDspecifies a four-component, 32-bit unsigned scaled format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, an 8-bit R component in byte 2, and an 8-bit A component in byte 3. -
VK_FORMAT_B8G8R8A8_SSCALEDspecifies a four-component, 32-bit signed scaled format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, an 8-bit R component in byte 2, and an 8-bit A component in byte 3. -
VK_FORMAT_B8G8R8A8_UINTspecifies a four-component, 32-bit unsigned integer format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, an 8-bit R component in byte 2, and an 8-bit A component in byte 3. -
VK_FORMAT_B8G8R8A8_SINTspecifies a four-component, 32-bit signed integer format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, an 8-bit R component in byte 2, and an 8-bit A component in byte 3. -
VK_FORMAT_B8G8R8A8_SRGBspecifies a four-component, 32-bit unsigned normalized format that has an 8-bit B component stored with sRGB nonlinear encoding in byte 0, an 8-bit G component stored with sRGB nonlinear encoding in byte 1, an 8-bit R component stored with sRGB nonlinear encoding in byte 2, and an 8-bit A component in byte 3. -
VK_FORMAT_A8B8G8R8_UNORM_PACK32specifies a four-component, 32-bit packed unsigned normalized format that has an 8-bit A component in bits 24..31, an 8-bit B component in bits 16..23, an 8-bit G component in bits 8..15, and an 8-bit R component in bits 0..7. -
VK_FORMAT_A8B8G8R8_SNORM_PACK32specifies a four-component, 32-bit packed signed normalized format that has an 8-bit A component in bits 24..31, an 8-bit B component in bits 16..23, an 8-bit G component in bits 8..15, and an 8-bit R component in bits 0..7. -
VK_FORMAT_A8B8G8R8_USCALED_PACK32specifies a four-component, 32-bit packed unsigned scaled integer format that has an 8-bit A component in bits 24..31, an 8-bit B component in bits 16..23, an 8-bit G component in bits 8..15, and an 8-bit R component in bits 0..7. -
VK_FORMAT_A8B8G8R8_SSCALED_PACK32specifies a four-component, 32-bit packed signed scaled integer format that has an 8-bit A component in bits 24..31, an 8-bit B component in bits 16..23, an 8-bit G component in bits 8..15, and an 8-bit R component in bits 0..7. -
VK_FORMAT_A8B8G8R8_UINT_PACK32specifies a four-component, 32-bit packed unsigned integer format that has an 8-bit A component in bits 24..31, an 8-bit B component in bits 16..23, an 8-bit G component in bits 8..15, and an 8-bit R component in bits 0..7. -
VK_FORMAT_A8B8G8R8_SINT_PACK32specifies a four-component, 32-bit packed signed integer format that has an 8-bit A component in bits 24..31, an 8-bit B component in bits 16..23, an 8-bit G component in bits 8..15, and an 8-bit R component in bits 0..7. -
VK_FORMAT_A8B8G8R8_SRGB_PACK32specifies a four-component, 32-bit packed unsigned normalized format that has an 8-bit A component in bits 24..31, an 8-bit B component stored with sRGB nonlinear encoding in bits 16..23, an 8-bit G component stored with sRGB nonlinear encoding in bits 8..15, and an 8-bit R component stored with sRGB nonlinear encoding in bits 0..7. -
VK_FORMAT_A2R10G10B10_UNORM_PACK32specifies a four-component, 32-bit packed unsigned normalized format that has a 2-bit A component in bits 30..31, a 10-bit R component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit B component in bits 0..9. -
VK_FORMAT_A2R10G10B10_SNORM_PACK32specifies a four-component, 32-bit packed signed normalized format that has a 2-bit A component in bits 30..31, a 10-bit R component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit B component in bits 0..9. -
VK_FORMAT_A2R10G10B10_USCALED_PACK32specifies a four-component, 32-bit packed unsigned scaled integer format that has a 2-bit A component in bits 30..31, a 10-bit R component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit B component in bits 0..9. -
VK_FORMAT_A2R10G10B10_SSCALED_PACK32specifies a four-component, 32-bit packed signed scaled integer format that has a 2-bit A component in bits 30..31, a 10-bit R component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit B component in bits 0..9. -
VK_FORMAT_A2R10G10B10_UINT_PACK32specifies a four-component, 32-bit packed unsigned integer format that has a 2-bit A component in bits 30..31, a 10-bit R component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit B component in bits 0..9. -
VK_FORMAT_A2R10G10B10_SINT_PACK32specifies a four-component, 32-bit packed signed integer format that has a 2-bit A component in bits 30..31, a 10-bit R component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit B component in bits 0..9. -
VK_FORMAT_A2B10G10R10_UNORM_PACK32specifies a four-component, 32-bit packed unsigned normalized format that has a 2-bit A component in bits 30..31, a 10-bit B component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit R component in bits 0..9. -
VK_FORMAT_A2B10G10R10_SNORM_PACK32specifies a four-component, 32-bit packed signed normalized format that has a 2-bit A component in bits 30..31, a 10-bit B component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit R component in bits 0..9. -
VK_FORMAT_A2B10G10R10_USCALED_PACK32specifies a four-component, 32-bit packed unsigned scaled integer format that has a 2-bit A component in bits 30..31, a 10-bit B component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit R component in bits 0..9. -
VK_FORMAT_A2B10G10R10_SSCALED_PACK32specifies a four-component, 32-bit packed signed scaled integer format that has a 2-bit A component in bits 30..31, a 10-bit B component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit R component in bits 0..9. -
VK_FORMAT_A2B10G10R10_UINT_PACK32specifies a four-component, 32-bit packed unsigned integer format that has a 2-bit A component in bits 30..31, a 10-bit B component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit R component in bits 0..9. -
VK_FORMAT_A2B10G10R10_SINT_PACK32specifies a four-component, 32-bit packed signed integer format that has a 2-bit A component in bits 30..31, a 10-bit B component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit R component in bits 0..9. -
VK_FORMAT_R16_UNORMspecifies a one-component, 16-bit unsigned normalized format that has a single 16-bit R component. -
VK_FORMAT_R16_SNORMspecifies a one-component, 16-bit signed normalized format that has a single 16-bit R component. -
VK_FORMAT_R16_USCALEDspecifies a one-component, 16-bit unsigned scaled integer format that has a single 16-bit R component. -
VK_FORMAT_R16_SSCALEDspecifies a one-component, 16-bit signed scaled integer format that has a single 16-bit R component. -
VK_FORMAT_R16_UINTspecifies a one-component, 16-bit unsigned integer format that has a single 16-bit R component. -
VK_FORMAT_R16_SINTspecifies a one-component, 16-bit signed integer format that has a single 16-bit R component. -
VK_FORMAT_R16_SFLOATspecifies a one-component, 16-bit signed floating-point format that has a single 16-bit R component. -
VK_FORMAT_R16G16_UNORMspecifies a two-component, 32-bit unsigned normalized format that has a 16-bit R component in bytes 0..1, and a 16-bit G component in bytes 2..3. -
VK_FORMAT_R16G16_SNORMspecifies a two-component, 32-bit signed normalized format that has a 16-bit R component in bytes 0..1, and a 16-bit G component in bytes 2..3. -
VK_FORMAT_R16G16_USCALEDspecifies a two-component, 32-bit unsigned scaled integer format that has a 16-bit R component in bytes 0..1, and a 16-bit G component in bytes 2..3. -
VK_FORMAT_R16G16_SSCALEDspecifies a two-component, 32-bit signed scaled integer format that has a 16-bit R component in bytes 0..1, and a 16-bit G component in bytes 2..3. -
VK_FORMAT_R16G16_UINTspecifies a two-component, 32-bit unsigned integer format that has a 16-bit R component in bytes 0..1, and a 16-bit G component in bytes 2..3. -
VK_FORMAT_R16G16_SINTspecifies a two-component, 32-bit signed integer format that has a 16-bit R component in bytes 0..1, and a 16-bit G component in bytes 2..3. -
VK_FORMAT_R16G16_SFLOATspecifies a two-component, 32-bit signed floating-point format that has a 16-bit R component in bytes 0..1, and a 16-bit G component in bytes 2..3. -
VK_FORMAT_R16G16B16_UNORMspecifies a three-component, 48-bit unsigned normalized format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, and a 16-bit B component in bytes 4..5. -
VK_FORMAT_R16G16B16_SNORMspecifies a three-component, 48-bit signed normalized format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, and a 16-bit B component in bytes 4..5. -
VK_FORMAT_R16G16B16_USCALEDspecifies a three-component, 48-bit unsigned scaled integer format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, and a 16-bit B component in bytes 4..5. -
VK_FORMAT_R16G16B16_SSCALEDspecifies a three-component, 48-bit signed scaled integer format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, and a 16-bit B component in bytes 4..5. -
VK_FORMAT_R16G16B16_UINTspecifies a three-component, 48-bit unsigned integer format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, and a 16-bit B component in bytes 4..5. -
VK_FORMAT_R16G16B16_SINTspecifies a three-component, 48-bit signed integer format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, and a 16-bit B component in bytes 4..5. -
VK_FORMAT_R16G16B16_SFLOATspecifies a three-component, 48-bit signed floating-point format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, and a 16-bit B component in bytes 4..5. -
VK_FORMAT_R16G16B16A16_UNORMspecifies a four-component, 64-bit unsigned normalized format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, a 16-bit B component in bytes 4..5, and a 16-bit A component in bytes 6..7. -
VK_FORMAT_R16G16B16A16_SNORMspecifies a four-component, 64-bit signed normalized format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, a 16-bit B component in bytes 4..5, and a 16-bit A component in bytes 6..7. -
VK_FORMAT_R16G16B16A16_USCALEDspecifies a four-component, 64-bit unsigned scaled integer format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, a 16-bit B component in bytes 4..5, and a 16-bit A component in bytes 6..7. -
VK_FORMAT_R16G16B16A16_SSCALEDspecifies a four-component, 64-bit signed scaled integer format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, a 16-bit B component in bytes 4..5, and a 16-bit A component in bytes 6..7. -
VK_FORMAT_R16G16B16A16_UINTspecifies a four-component, 64-bit unsigned integer format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, a 16-bit B component in bytes 4..5, and a 16-bit A component in bytes 6..7. -
VK_FORMAT_R16G16B16A16_SINTspecifies a four-component, 64-bit signed integer format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, a 16-bit B component in bytes 4..5, and a 16-bit A component in bytes 6..7. -
VK_FORMAT_R16G16B16A16_SFLOATspecifies a four-component, 64-bit signed floating-point format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, a 16-bit B component in bytes 4..5, and a 16-bit A component in bytes 6..7. -
VK_FORMAT_R32_UINTspecifies a one-component, 32-bit unsigned integer format that has a single 32-bit R component. -
VK_FORMAT_R32_SINTspecifies a one-component, 32-bit signed integer format that has a single 32-bit R component. -
VK_FORMAT_R32_SFLOATspecifies a one-component, 32-bit signed floating-point format that has a single 32-bit R component. -
VK_FORMAT_R32G32_UINTspecifies a two-component, 64-bit unsigned integer format that has a 32-bit R component in bytes 0..3, and a 32-bit G component in bytes 4..7. -
VK_FORMAT_R32G32_SINTspecifies a two-component, 64-bit signed integer format that has a 32-bit R component in bytes 0..3, and a 32-bit G component in bytes 4..7. -
VK_FORMAT_R32G32_SFLOATspecifies a two-component, 64-bit signed floating-point format that has a 32-bit R component in bytes 0..3, and a 32-bit G component in bytes 4..7. -
VK_FORMAT_R32G32B32_UINTspecifies a three-component, 96-bit unsigned integer format that has a 32-bit R component in bytes 0..3, a 32-bit G component in bytes 4..7, and a 32-bit B component in bytes 8..11. -
VK_FORMAT_R32G32B32_SINTspecifies a three-component, 96-bit signed integer format that has a 32-bit R component in bytes 0..3, a 32-bit G component in bytes 4..7, and a 32-bit B component in bytes 8..11. -
VK_FORMAT_R32G32B32_SFLOATspecifies a three-component, 96-bit signed floating-point format that has a 32-bit R component in bytes 0..3, a 32-bit G component in bytes 4..7, and a 32-bit B component in bytes 8..11. -
VK_FORMAT_R32G32B32A32_UINTspecifies a four-component, 128-bit unsigned integer format that has a 32-bit R component in bytes 0..3, a 32-bit G component in bytes 4..7, a 32-bit B component in bytes 8..11, and a 32-bit A component in bytes 12..15. -
VK_FORMAT_R32G32B32A32_SINTspecifies a four-component, 128-bit signed integer format that has a 32-bit R component in bytes 0..3, a 32-bit G component in bytes 4..7, a 32-bit B component in bytes 8..11, and a 32-bit A component in bytes 12..15. -
VK_FORMAT_R32G32B32A32_SFLOATspecifies a four-component, 128-bit signed floating-point format that has a 32-bit R component in bytes 0..3, a 32-bit G component in bytes 4..7, a 32-bit B component in bytes 8..11, and a 32-bit A component in bytes 12..15. -
VK_FORMAT_R64_UINTspecifies a one-component, 64-bit unsigned integer format that has a single 64-bit R component. -
VK_FORMAT_R64_SINTspecifies a one-component, 64-bit signed integer format that has a single 64-bit R component. -
VK_FORMAT_R64_SFLOATspecifies a one-component, 64-bit signed floating-point format that has a single 64-bit R component. -
VK_FORMAT_R64G64_UINTspecifies a two-component, 128-bit unsigned integer format that has a 64-bit R component in bytes 0..7, and a 64-bit G component in bytes 8..15. -
VK_FORMAT_R64G64_SINTspecifies a two-component, 128-bit signed integer format that has a 64-bit R component in bytes 0..7, and a 64-bit G component in bytes 8..15. -
VK_FORMAT_R64G64_SFLOATspecifies a two-component, 128-bit signed floating-point format that has a 64-bit R component in bytes 0..7, and a 64-bit G component in bytes 8..15. -
VK_FORMAT_R64G64B64_UINTspecifies a three-component, 192-bit unsigned integer format that has a 64-bit R component in bytes 0..7, a 64-bit G component in bytes 8..15, and a 64-bit B component in bytes 16..23. -
VK_FORMAT_R64G64B64_SINTspecifies a three-component, 192-bit signed integer format that has a 64-bit R component in bytes 0..7, a 64-bit G component in bytes 8..15, and a 64-bit B component in bytes 16..23. -
VK_FORMAT_R64G64B64_SFLOATspecifies a three-component, 192-bit signed floating-point format that has a 64-bit R component in bytes 0..7, a 64-bit G component in bytes 8..15, and a 64-bit B component in bytes 16..23. -
VK_FORMAT_R64G64B64A64_UINTspecifies a four-component, 256-bit unsigned integer format that has a 64-bit R component in bytes 0..7, a 64-bit G component in bytes 8..15, a 64-bit B component in bytes 16..23, and a 64-bit A component in bytes 24..31. -
VK_FORMAT_R64G64B64A64_SINTspecifies a four-component, 256-bit signed integer format that has a 64-bit R component in bytes 0..7, a 64-bit G component in bytes 8..15, a 64-bit B component in bytes 16..23, and a 64-bit A component in bytes 24..31. -
VK_FORMAT_R64G64B64A64_SFLOATspecifies a four-component, 256-bit signed floating-point format that has a 64-bit R component in bytes 0..7, a 64-bit G component in bytes 8..15, a 64-bit B component in bytes 16..23, and a 64-bit A component in bytes 24..31. -
VK_FORMAT_B10G11R11_UFLOAT_PACK32specifies a three-component, 32-bit packed unsigned floating-point format that has a 10-bit B component in bits 22..31, an 11-bit G component in bits 11..21, an 11-bit R component in bits 0..10. See Unsigned 10-Bit Floating-Point Numbers and Unsigned 11-Bit Floating-Point Numbers. -
VK_FORMAT_E5B9G9R9_UFLOAT_PACK32specifies a three-component, 32-bit packed unsigned floating-point format that has a 5-bit shared exponent in bits 27..31, a 9-bit B component mantissa in bits 18..26, a 9-bit G component mantissa in bits 9..17, and a 9-bit R component mantissa in bits 0..8. -
VK_FORMAT_D16_UNORMspecifies a one-component, 16-bit unsigned normalized format that has a single 16-bit depth component. -
VK_FORMAT_X8_D24_UNORM_PACK32specifies a two-component, 32-bit format that has 24 unsigned normalized bits in the depth component and, optionally:, 8 bits that are unused. -
VK_FORMAT_D32_SFLOATspecifies a one-component, 32-bit signed floating-point format that has 32-bits in the depth component. -
VK_FORMAT_S8_UINTspecifies a one-component, 8-bit unsigned integer format that has 8-bits in the stencil component. -
VK_FORMAT_D16_UNORM_S8_UINTspecifies a two-component, 24-bit format that has 16 unsigned normalized bits in the depth component and 8 unsigned integer bits in the stencil component. -
VK_FORMAT_D24_UNORM_S8_UINTspecifies a two-component, 32-bit packed format that has 8 unsigned integer bits in the stencil component, and 24 unsigned normalized bits in the depth component. -
VK_FORMAT_D32_SFLOAT_S8_UINTspecifies a two-component format that has 32 signed float bits in the depth component and 8 unsigned integer bits in the stencil component. There are optionally: 24-bits that are unused. -
VK_FORMAT_BC1_RGB_UNORM_BLOCKspecifies a three-component, block-compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGB texel data. This format has no alpha and is considered opaque. -
VK_FORMAT_BC1_RGB_SRGB_BLOCKspecifies a three-component, block-compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGB texel data with sRGB nonlinear encoding. This format has no alpha and is considered opaque. -
VK_FORMAT_BC1_RGBA_UNORM_BLOCKspecifies a four-component, block-compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGB texel data, and provides 1 bit of alpha. -
VK_FORMAT_BC1_RGBA_SRGB_BLOCKspecifies a four-component, block-compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGB texel data with sRGB nonlinear encoding, and provides 1 bit of alpha. -
VK_FORMAT_BC2_UNORM_BLOCKspecifies a four-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data with the first 64 bits encoding alpha values followed by 64 bits encoding RGB values. -
VK_FORMAT_BC2_SRGB_BLOCKspecifies a four-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data with the first 64 bits encoding alpha values followed by 64 bits encoding RGB values with sRGB nonlinear encoding. -
VK_FORMAT_BC3_UNORM_BLOCKspecifies a four-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data with the first 64 bits encoding alpha values followed by 64 bits encoding RGB values. -
VK_FORMAT_BC3_SRGB_BLOCKspecifies a four-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data with the first 64 bits encoding alpha values followed by 64 bits encoding RGB values with sRGB nonlinear encoding. -
VK_FORMAT_BC4_UNORM_BLOCKspecifies a one-component, block-compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized red texel data. -
VK_FORMAT_BC4_SNORM_BLOCKspecifies a one-component, block-compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of signed normalized red texel data. -
VK_FORMAT_BC5_UNORM_BLOCKspecifies a two-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RG texel data with the first 64 bits encoding red values followed by 64 bits encoding green values. -
VK_FORMAT_BC5_SNORM_BLOCKspecifies a two-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of signed normalized RG texel data with the first 64 bits encoding red values followed by 64 bits encoding green values. -
VK_FORMAT_BC6H_UFLOAT_BLOCKspecifies a three-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned floating-point RGB texel data. -
VK_FORMAT_BC6H_SFLOAT_BLOCKspecifies a three-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of signed floating-point RGB texel data. -
VK_FORMAT_BC7_UNORM_BLOCKspecifies a four-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data. -
VK_FORMAT_BC7_SRGB_BLOCKspecifies a four-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components. -
VK_FORMAT_ETC2_R8G8B8_UNORM_BLOCKspecifies a three-component, ETC2 compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGB texel data. This format has no alpha and is considered opaque. -
VK_FORMAT_ETC2_R8G8B8_SRGB_BLOCKspecifies a three-component, ETC2 compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGB texel data with sRGB nonlinear encoding. This format has no alpha and is considered opaque. -
VK_FORMAT_ETC2_R8G8B8A1_UNORM_BLOCKspecifies a four-component, ETC2 compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGB texel data, and provides 1 bit of alpha. -
VK_FORMAT_ETC2_R8G8B8A1_SRGB_BLOCKspecifies a four-component, ETC2 compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGB texel data with sRGB nonlinear encoding, and provides 1 bit of alpha. -
VK_FORMAT_ETC2_R8G8B8A8_UNORM_BLOCKspecifies a four-component, ETC2 compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data with the first 64 bits encoding alpha values followed by 64 bits encoding RGB values. -
VK_FORMAT_ETC2_R8G8B8A8_SRGB_BLOCKspecifies a four-component, ETC2 compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data with the first 64 bits encoding alpha values followed by 64 bits encoding RGB values with sRGB nonlinear encoding applied. -
VK_FORMAT_EAC_R11_UNORM_BLOCKspecifies a one-component, ETC2 compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized red texel data. -
VK_FORMAT_EAC_R11_SNORM_BLOCKspecifies a one-component, ETC2 compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of signed normalized red texel data. -
VK_FORMAT_EAC_R11G11_UNORM_BLOCKspecifies a two-component, ETC2 compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RG texel data with the first 64 bits encoding red values followed by 64 bits encoding green values. -
VK_FORMAT_EAC_R11G11_SNORM_BLOCKspecifies a two-component, ETC2 compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of signed normalized RG texel data with the first 64 bits encoding red values followed by 64 bits encoding green values. -
VK_FORMAT_ASTC_4x4_UNORM_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data. -
VK_FORMAT_ASTC_4x4_SRGB_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components. -
VK_FORMAT_ASTC_5x4_UNORM_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 5×4 rectangle of unsigned normalized RGBA texel data. -
VK_FORMAT_ASTC_5x4_SRGB_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 5×4 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components. -
VK_FORMAT_ASTC_5x5_UNORM_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 5×5 rectangle of unsigned normalized RGBA texel data. -
VK_FORMAT_ASTC_5x5_SRGB_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 5×5 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components. -
VK_FORMAT_ASTC_6x5_UNORM_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 6×5 rectangle of unsigned normalized RGBA texel data. -
VK_FORMAT_ASTC_6x5_SRGB_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 6×5 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components. -
VK_FORMAT_ASTC_6x6_UNORM_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 6×6 rectangle of unsigned normalized RGBA texel data. -
VK_FORMAT_ASTC_6x6_SRGB_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 6×6 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components. -
VK_FORMAT_ASTC_8x5_UNORM_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes an 8×5 rectangle of unsigned normalized RGBA texel data. -
VK_FORMAT_ASTC_8x5_SRGB_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes an 8×5 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components. -
VK_FORMAT_ASTC_8x6_UNORM_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes an 8×6 rectangle of unsigned normalized RGBA texel data. -
VK_FORMAT_ASTC_8x6_SRGB_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes an 8×6 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components. -
VK_FORMAT_ASTC_8x8_UNORM_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes an 8×8 rectangle of unsigned normalized RGBA texel data. -
VK_FORMAT_ASTC_8x8_SRGB_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes an 8×8 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components. -
VK_FORMAT_ASTC_10x5_UNORM_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×5 rectangle of unsigned normalized RGBA texel data. -
VK_FORMAT_ASTC_10x5_SRGB_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×5 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components. -
VK_FORMAT_ASTC_10x6_UNORM_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×6 rectangle of unsigned normalized RGBA texel data. -
VK_FORMAT_ASTC_10x6_SRGB_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×6 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components. -
VK_FORMAT_ASTC_10x8_UNORM_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×8 rectangle of unsigned normalized RGBA texel data. -
VK_FORMAT_ASTC_10x8_SRGB_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×8 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components. -
VK_FORMAT_ASTC_10x10_UNORM_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×10 rectangle of unsigned normalized RGBA texel data. -
VK_FORMAT_ASTC_10x10_SRGB_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×10 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components. -
VK_FORMAT_ASTC_12x10_UNORM_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 12×10 rectangle of unsigned normalized RGBA texel data. -
VK_FORMAT_ASTC_12x10_SRGB_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 12×10 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components. -
VK_FORMAT_ASTC_12x12_UNORM_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 12×12 rectangle of unsigned normalized RGBA texel data. -
VK_FORMAT_ASTC_12x12_SRGB_BLOCKspecifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 12×12 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components. -
VK_FORMAT_G8B8G8R8_422_UNORMspecifies a four-component, 32-bit format containing a pair of G components, an R component, and a B component, collectively encoding a 2×1 rectangle of unsigned normalized RGB texel data. One G value is present at each i coordinate, with the B and R values shared across both G values and thus recorded at half the horizontal resolution of the image. This format has an 8-bit G component for the even i coordinate in byte 0, an 8-bit B component in byte 1, an 8-bit G component for the odd i coordinate in byte 2, and an 8-bit R component in byte 3. Images in this format must be defined with a width that is a multiple of two. For the purposes of the constraints on copy extents, this format is treated as a compressed format with a 2×1 compressed texel block. -
VK_FORMAT_B8G8R8G8_422_UNORMspecifies a four-component, 32-bit format containing a pair of G components, an R component, and a B component, collectively encoding a 2×1 rectangle of unsigned normalized RGB texel data. One G value is present at each i coordinate, with the B and R values shared across both G values and thus recorded at half the horizontal resolution of the image. This format has an 8-bit B component in byte 0, an 8-bit G component for the even i coordinate in byte 1, an 8-bit R component in byte 2, and an 8-bit G component for the odd i coordinate in byte 3. Images in this format must be defined with a width that is a multiple of two. For the purposes of the constraints on copy extents, this format is treated as a compressed format with a 2×1 compressed texel block. -
VK_FORMAT_G8_B8_R8_3PLANE_420_UNORMspecifies a unsigned normalized multi-planar format that has an 8-bit G component in plane 0, an 8-bit B component in plane 1, and an 8-bit R component in plane 2. The horizontal and vertical dimensions of the R and B planes are halved relative to the image dimensions, and each R and B component is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\) and \(\lfloor j_G \times 0.5 \rfloor = j_B = j_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane,VK_IMAGE_ASPECT_PLANE_1_BITfor the B plane, andVK_IMAGE_ASPECT_PLANE_2_BITfor the R plane. Images in this format must be defined with a width and height that is a multiple of two. -
VK_FORMAT_G8_B8R8_2PLANE_420_UNORMspecifies a unsigned normalized multi-planar format that has an 8-bit G component in plane 0, and a two-component, 16-bit BR plane 1 consisting of an 8-bit B component in byte 0 and an 8-bit R component in byte 1. The horizontal and vertical dimensions of the BR plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\) and \(\lfloor j_G \times 0.5 \rfloor = j_B = j_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane, andVK_IMAGE_ASPECT_PLANE_1_BITfor the BR plane. Images in this format must be defined with a width and height that is a multiple of two. -
VK_FORMAT_G8_B8_R8_3PLANE_422_UNORMspecifies a unsigned normalized multi-planar format that has an 8-bit G component in plane 0, an 8-bit B component in plane 1, and an 8-bit R component in plane 2. The horizontal dimension of the R and B plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane,VK_IMAGE_ASPECT_PLANE_1_BITfor the B plane, andVK_IMAGE_ASPECT_PLANE_2_BITfor the R plane. Images in this format must be defined with a width that is a multiple of two. -
VK_FORMAT_G8_B8R8_2PLANE_422_UNORMspecifies a unsigned normalized multi-planar format that has an 8-bit G component in plane 0, and a two-component, 16-bit BR plane 1 consisting of an 8-bit B component in byte 0 and an 8-bit R component in byte 1. The horizontal dimensions of the BR plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane, andVK_IMAGE_ASPECT_PLANE_1_BITfor the BR plane. Images in this format must be defined with a width that is a multiple of two. -
VK_FORMAT_G8_B8_R8_3PLANE_444_UNORMspecifies a unsigned normalized multi-planar format that has an 8-bit G component in plane 0, an 8-bit B component in plane 1, and an 8-bit R component in plane 2. Each plane has the same dimensions and each R, G and B component contributes to a single texel. The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane,VK_IMAGE_ASPECT_PLANE_1_BITfor the B plane, andVK_IMAGE_ASPECT_PLANE_2_BITfor the R plane. -
VK_FORMAT_R10X6_UNORM_PACK16specifies a one-component, 16-bit unsigned normalized format that has a single 10-bit R component in the top 10 bits of a 16-bit word, with the bottom 6 bits set to 0. -
VK_FORMAT_R10X6G10X6_UNORM_2PACK16specifies a two-component, 32-bit unsigned normalized format that has a 10-bit R component in the top 10 bits of the word in bytes 0..1, and a 10-bit G component in the top 10 bits of the word in bytes 2..3, with the bottom 6 bits of each word set to 0. -
VK_FORMAT_R10X6G10X6B10X6A10X6_UNORM_4PACK16specifies a four-component, 64-bit unsigned normalized format that has a 10-bit R component in the top 10 bits of the word in bytes 0..1, a 10-bit G component in the top 10 bits of the word in bytes 2..3, a 10-bit B component in the top 10 bits of the word in bytes 4..5, and a 10-bit A component in the top 10 bits of the word in bytes 6..7, with the bottom 6 bits of each word set to 0. -
VK_FORMAT_G10X6B10X6G10X6R10X6_422_UNORM_4PACK16specifies a four-component, 64-bit format containing a pair of G components, an R component, and a B component, collectively encoding a 2×1 rectangle of unsigned normalized RGB texel data. One G value is present at each i coordinate, with the B and R values shared across both G values and thus recorded at half the horizontal resolution of the image. This format has a 10-bit G component for the even i coordinate in the top 10 bits of the word in bytes 0..1, a 10-bit B component in the top 10 bits of the word in bytes 2..3, a 10-bit G component for the odd i coordinate in the top 10 bits of the word in bytes 4..5, and a 10-bit R component in the top 10 bits of the word in bytes 6..7, with the bottom 6 bits of each word set to 0. Images in this format must be defined with a width that is a multiple of two. For the purposes of the constraints on copy extents, this format is treated as a compressed format with a 2×1 compressed texel block. -
VK_FORMAT_B10X6G10X6R10X6G10X6_422_UNORM_4PACK16specifies a four-component, 64-bit format containing a pair of G components, an R component, and a B component, collectively encoding a 2×1 rectangle of unsigned normalized RGB texel data. One G value is present at each i coordinate, with the B and R values shared across both G values and thus recorded at half the horizontal resolution of the image. This format has a 10-bit B component in the top 10 bits of the word in bytes 0..1, a 10-bit G component for the even i coordinate in the top 10 bits of the word in bytes 2..3, a 10-bit R component in the top 10 bits of the word in bytes 4..5, and a 10-bit G component for the odd i coordinate in the top 10 bits of the word in bytes 6..7, with the bottom 6 bits of each word set to 0. Images in this format must be defined with a width that is a multiple of two. For the purposes of the constraints on copy extents, this format is treated as a compressed format with a 2×1 compressed texel block. -
VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_420_UNORM_3PACK16specifies a unsigned normalized multi-planar format that has a 10-bit G component in the top 10 bits of each 16-bit word of plane 0, a 10-bit B component in the top 10 bits of each 16-bit word of plane 1, and a 10-bit R component in the top 10 bits of each 16-bit word of plane 2, with the bottom 6 bits of each word set to 0. The horizontal and vertical dimensions of the R and B planes are halved relative to the image dimensions, and each R and B component is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\) and \(\lfloor j_G \times 0.5 \rfloor = j_B = j_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane,VK_IMAGE_ASPECT_PLANE_1_BITfor the B plane, andVK_IMAGE_ASPECT_PLANE_2_BITfor the R plane. Images in this format must be defined with a width and height that is a multiple of two. -
VK_FORMAT_G10X6_B10X6R10X6_2PLANE_420_UNORM_3PACK16specifies a unsigned normalized multi-planar format that has a 10-bit G component in the top 10 bits of each 16-bit word of plane 0, and a two-component, 32-bit BR plane 1 consisting of a 10-bit B component in the top 10 bits of the word in bytes 0..1, and a 10-bit R component in the top 10 bits of the word in bytes 2..3, the bottom 6 bits of each word set to 0. The horizontal and vertical dimensions of the BR plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\) and \(\lfloor j_G \times 0.5 \rfloor = j_B = j_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane, andVK_IMAGE_ASPECT_PLANE_1_BITfor the BR plane. Images in this format must be defined with a width and height that is a multiple of two. -
VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_422_UNORM_3PACK16specifies a unsigned normalized multi-planar format that has a 10-bit G component in the top 10 bits of each 16-bit word of plane 0, a 10-bit B component in the top 10 bits of each 16-bit word of plane 1, and a 10-bit R component in the top 10 bits of each 16-bit word of plane 2, with the bottom 6 bits of each word set to 0. The horizontal dimension of the R and B plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane,VK_IMAGE_ASPECT_PLANE_1_BITfor the B plane, andVK_IMAGE_ASPECT_PLANE_2_BITfor the R plane. Images in this format must be defined with a width that is a multiple of two. -
VK_FORMAT_G10X6_B10X6R10X6_2PLANE_422_UNORM_3PACK16specifies a unsigned normalized multi-planar format that has a 10-bit G component in the top 10 bits of each 16-bit word of plane 0, and a two-component, 32-bit BR plane 1 consisting of a 10-bit B component in the top 10 bits of the word in bytes 0..1, and a 10-bit R component in the top 10 bits of the word in bytes 2..3, the bottom 6 bits of each word set to 0. The horizontal dimensions of the BR plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane, andVK_IMAGE_ASPECT_PLANE_1_BITfor the BR plane. Images in this format must be defined with a width that is a multiple of two. -
VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_444_UNORM_3PACK16specifies a unsigned normalized multi-planar format that has a 10-bit G component in the top 10 bits of each 16-bit word of plane 0, a 10-bit B component in the top 10 bits of each 16-bit word of plane 1, and a 10-bit R component in the top 10 bits of each 16-bit word of plane 2, with the bottom 6 bits of each word set to 0. Each plane has the same dimensions and each R, G and B component contributes to a single texel. The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane,VK_IMAGE_ASPECT_PLANE_1_BITfor the B plane, andVK_IMAGE_ASPECT_PLANE_2_BITfor the R plane. -
VK_FORMAT_R12X4_UNORM_PACK16specifies a one-component, 16-bit unsigned normalized format that has a single 12-bit R component in the top 12 bits of a 16-bit word, with the bottom 4 bits set to 0. -
VK_FORMAT_R12X4G12X4_UNORM_2PACK16specifies a two-component, 32-bit unsigned normalized format that has a 12-bit R component in the top 12 bits of the word in bytes 0..1, and a 12-bit G component in the top 12 bits of the word in bytes 2..3, with the bottom 4 bits of each word set to 0. -
VK_FORMAT_R12X4G12X4B12X4A12X4_UNORM_4PACK16specifies a four-component, 64-bit unsigned normalized format that has a 12-bit R component in the top 12 bits of the word in bytes 0..1, a 12-bit G component in the top 12 bits of the word in bytes 2..3, a 12-bit B component in the top 12 bits of the word in bytes 4..5, and a 12-bit A component in the top 12 bits of the word in bytes 6..7, with the bottom 4 bits of each word set to 0. -
VK_FORMAT_G12X4B12X4G12X4R12X4_422_UNORM_4PACK16specifies a four-component, 64-bit format containing a pair of G components, an R component, and a B component, collectively encoding a 2×1 rectangle of unsigned normalized RGB texel data. One G value is present at each i coordinate, with the B and R values shared across both G values and thus recorded at half the horizontal resolution of the image. This format has a 12-bit G component for the even i coordinate in the top 12 bits of the word in bytes 0..1, a 12-bit B component in the top 12 bits of the word in bytes 2..3, a 12-bit G component for the odd i coordinate in the top 12 bits of the word in bytes 4..5, and a 12-bit R component in the top 12 bits of the word in bytes 6..7, with the bottom 4 bits of each word set to 0. Images in this format must be defined with a width that is a multiple of two. For the purposes of the constraints on copy extents, this format is treated as a compressed format with a 2×1 compressed texel block. -
VK_FORMAT_B12X4G12X4R12X4G12X4_422_UNORM_4PACK16specifies a four-component, 64-bit format containing a pair of G components, an R component, and a B component, collectively encoding a 2×1 rectangle of unsigned normalized RGB texel data. One G value is present at each i coordinate, with the B and R values shared across both G values and thus recorded at half the horizontal resolution of the image. This format has a 12-bit B component in the top 12 bits of the word in bytes 0..1, a 12-bit G component for the even i coordinate in the top 12 bits of the word in bytes 2..3, a 12-bit R component in the top 12 bits of the word in bytes 4..5, and a 12-bit G component for the odd i coordinate in the top 12 bits of the word in bytes 6..7, with the bottom 4 bits of each word set to 0. Images in this format must be defined with a width that is a multiple of two. For the purposes of the constraints on copy extents, this format is treated as a compressed format with a 2×1 compressed texel block. -
VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_420_UNORM_3PACK16specifies a unsigned normalized multi-planar format that has a 12-bit G component in the top 12 bits of each 16-bit word of plane 0, a 12-bit B component in the top 12 bits of each 16-bit word of plane 1, and a 12-bit R component in the top 12 bits of each 16-bit word of plane 2, with the bottom 4 bits of each word set to 0. The horizontal and vertical dimensions of the R and B planes are halved relative to the image dimensions, and each R and B component is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\) and \(\lfloor j_G \times 0.5 \rfloor = j_B = j_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane,VK_IMAGE_ASPECT_PLANE_1_BITfor the B plane, andVK_IMAGE_ASPECT_PLANE_2_BITfor the R plane. Images in this format must be defined with a width and height that is a multiple of two. -
VK_FORMAT_G12X4_B12X4R12X4_2PLANE_420_UNORM_3PACK16specifies a unsigned normalized multi-planar format that has a 12-bit G component in the top 12 bits of each 16-bit word of plane 0, and a two-component, 32-bit BR plane 1 consisting of a 12-bit B component in the top 12 bits of the word in bytes 0..1, and a 12-bit R component in the top 12 bits of the word in bytes 2..3, the bottom 4 bits of each word set to 0. The horizontal and vertical dimensions of the BR plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\) and \(\lfloor j_G \times 0.5 \rfloor = j_B = j_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane, andVK_IMAGE_ASPECT_PLANE_1_BITfor the BR plane. Images in this format must be defined with a width and height that is a multiple of two. -
VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_422_UNORM_3PACK16specifies a unsigned normalized multi-planar format that has a 12-bit G component in the top 12 bits of each 16-bit word of plane 0, a 12-bit B component in the top 12 bits of each 16-bit word of plane 1, and a 12-bit R component in the top 12 bits of each 16-bit word of plane 2, with the bottom 4 bits of each word set to 0. The horizontal dimension of the R and B plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane,VK_IMAGE_ASPECT_PLANE_1_BITfor the B plane, andVK_IMAGE_ASPECT_PLANE_2_BITfor the R plane. Images in this format must be defined with a width that is a multiple of two. -
VK_FORMAT_G12X4_B12X4R12X4_2PLANE_422_UNORM_3PACK16specifies a unsigned normalized multi-planar format that has a 12-bit G component in the top 12 bits of each 16-bit word of plane 0, and a two-component, 32-bit BR plane 1 consisting of a 12-bit B component in the top 12 bits of the word in bytes 0..1, and a 12-bit R component in the top 12 bits of the word in bytes 2..3, the bottom 4 bits of each word set to 0. The horizontal dimensions of the BR plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane, andVK_IMAGE_ASPECT_PLANE_1_BITfor the BR plane. Images in this format must be defined with a width that is a multiple of two. -
VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_444_UNORM_3PACK16specifies a unsigned normalized multi-planar format that has a 12-bit G component in the top 12 bits of each 16-bit word of plane 0, a 12-bit B component in the top 12 bits of each 16-bit word of plane 1, and a 12-bit R component in the top 12 bits of each 16-bit word of plane 2, with the bottom 4 bits of each word set to 0. Each plane has the same dimensions and each R, G and B component contributes to a single texel. The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane,VK_IMAGE_ASPECT_PLANE_1_BITfor the B plane, andVK_IMAGE_ASPECT_PLANE_2_BITfor the R plane. -
VK_FORMAT_G16B16G16R16_422_UNORMspecifies a four-component, 64-bit format containing a pair of G components, an R component, and a B component, collectively encoding a 2×1 rectangle of unsigned normalized RGB texel data. One G value is present at each i coordinate, with the B and R values shared across both G values and thus recorded at half the horizontal resolution of the image. This format has a 16-bit G component for the even i coordinate in the word in bytes 0..1, a 16-bit B component in the word in bytes 2..3, a 16-bit G component for the odd i coordinate in the word in bytes 4..5, and a 16-bit R component in the word in bytes 6..7. Images in this format must be defined with a width that is a multiple of two. For the purposes of the constraints on copy extents, this format is treated as a compressed format with a 2×1 compressed texel block. -
VK_FORMAT_B16G16R16G16_422_UNORMspecifies a four-component, 64-bit format containing a pair of G components, an R component, and a B component, collectively encoding a 2×1 rectangle of unsigned normalized RGB texel data. One G value is present at each i coordinate, with the B and R values shared across both G values and thus recorded at half the horizontal resolution of the image. This format has a 16-bit B component in the word in bytes 0..1, a 16-bit G component for the even i coordinate in the word in bytes 2..3, a 16-bit R component in the word in bytes 4..5, and a 16-bit G component for the odd i coordinate in the word in bytes 6..7. Images in this format must be defined with a width that is a multiple of two. For the purposes of the constraints on copy extents, this format is treated as a compressed format with a 2×1 compressed texel block. -
VK_FORMAT_G16_B16_R16_3PLANE_420_UNORMspecifies a unsigned normalized multi-planar format that has a 16-bit G component in each 16-bit word of plane 0, a 16-bit B component in each 16-bit word of plane 1, and a 16-bit R component in each 16-bit word of plane 2. The horizontal and vertical dimensions of the R and B planes are halved relative to the image dimensions, and each R and B component is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\) and \(\lfloor j_G \times 0.5 \rfloor = j_B = j_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane,VK_IMAGE_ASPECT_PLANE_1_BITfor the B plane, andVK_IMAGE_ASPECT_PLANE_2_BITfor the R plane. Images in this format must be defined with a width and height that is a multiple of two. -
VK_FORMAT_G16_B16R16_2PLANE_420_UNORMspecifies a unsigned normalized multi-planar format that has a 16-bit G component in each 16-bit word of plane 0, and a two-component, 32-bit BR plane 1 consisting of a 16-bit B component in the word in bytes 0..1, and a 16-bit R component in the word in bytes 2..3. The horizontal and vertical dimensions of the BR plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\) and \(\lfloor j_G \times 0.5 \rfloor = j_B = j_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane, andVK_IMAGE_ASPECT_PLANE_1_BITfor the BR plane. Images in this format must be defined with a width and height that is a multiple of two. -
VK_FORMAT_G16_B16_R16_3PLANE_422_UNORMspecifies a unsigned normalized multi-planar format that has a 16-bit G component in each 16-bit word of plane 0, a 16-bit B component in each 16-bit word of plane 1, and a 16-bit R component in each 16-bit word of plane 2. The horizontal dimension of the R and B plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane,VK_IMAGE_ASPECT_PLANE_1_BITfor the B plane, andVK_IMAGE_ASPECT_PLANE_2_BITfor the R plane. Images in this format must be defined with a width that is a multiple of two. -
VK_FORMAT_G16_B16R16_2PLANE_422_UNORMspecifies a unsigned normalized multi-planar format that has a 16-bit G component in each 16-bit word of plane 0, and a two-component, 32-bit BR plane 1 consisting of a 16-bit B component in the word in bytes 0..1, and a 16-bit R component in the word in bytes 2..3. The horizontal dimensions of the BR plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane, andVK_IMAGE_ASPECT_PLANE_1_BITfor the BR plane. Images in this format must be defined with a width that is a multiple of two. -
VK_FORMAT_G16_B16_R16_3PLANE_444_UNORMspecifies a unsigned normalized multi-planar format that has a 16-bit G component in each 16-bit word of plane 0, a 16-bit B component in each 16-bit word of plane 1, and a 16-bit R component in each 16-bit word of plane 2. Each plane has the same dimensions and each R, G and B component contributes to a single texel. The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, usingVK_IMAGE_ASPECT_PLANE_0_BITfor the G plane,VK_IMAGE_ASPECT_PLANE_1_BITfor the B plane, andVK_IMAGE_ASPECT_PLANE_2_BITfor the R plane.
Compatible formats of planes of multi-planar formats
Individual planes of multi-planar formats are compatible with single-plane formats if they occupy the same number of bits per data element. In the following table, individual planes of a multi-planar format are compatible with the format listed against the relevant plane index for that multi-planar format.
| Plane | Compatible format for plane | Width relative to the width w of the plane with the largest dimensions | Height relative to the height h of the plane with the largest dimensions |
|---|---|---|---|
|
|||
0 |
|
w |
h |
1 |
|
w/2 |
h/2 |
2 |
|
w/2 |
h/2 |
|
|||
0 |
|
w |
h |
1 |
|
w/2 |
h/2 |
|
|||
0 |
|
w |
h |
1 |
|
w/2 |
h |
2 |
|
w/2 |
h |
|
|||
0 |
|
w |
h |
1 |
|
w/2 |
h |
|
|||
0 |
|
w |
h |
1 |
|
w |
h |
2 |
|
w |
h |
|
|||
0 |
|
w |
h |
1 |
|
w/2 |
h/2 |
2 |
|
w/2 |
h/2 |
|
|||
0 |
|
w |
h |
1 |
|
w/2 |
h/2 |
|
|||
0 |
|
w |
h |
1 |
|
w/2 |
h |
2 |
|
w/2 |
h |
|
|||
0 |
|
w |
h |
1 |
|
w/2 |
h |
|
|||
0 |
|
w |
h |
1 |
|
w |
h |
2 |
|
w |
h |
|
|||
0 |
|
w |
h |
1 |
|
w/2 |
h/2 |
2 |
|
w/2 |
h/2 |
|
|||
0 |
|
w |
h |
1 |
|
w/2 |
h/2 |
|
|||
0 |
|
w |
h |
1 |
|
w/2 |
h |
2 |
|
w/2 |
h |
|
|||
0 |
|
w |
h |
1 |
|
w/2 |
h |
|
|||
0 |
|
w |
h |
1 |
|
w |
h |
2 |
|
w |
h |
|
|||
0 |
|
w |
h |
1 |
|
w/2 |
h/2 |
2 |
|
w/2 |
h/2 |
|
|||
0 |
|
w |
h |
1 |
|
w/2 |
h/2 |
|
|||
0 |
|
w |
h |
1 |
|
w/2 |
h |
2 |
|
w/2 |
h |
|
|||
0 |
|
w |
h |
1 |
|
w/2 |
h |
|
|||
0 |
|
w |
h |
1 |
|
w |
h |
2 |
|
w |
h |
Packed Formats
For the purposes of address alignment when accessing buffer memory containing vertex attribute or texel data, the following formats are considered packed - whole texels or attributes are stored in a single data element, rather than individual components occupying a single data element:
-
-
VK_FORMAT_R4G4_UNORM_PACK8
-
-
Packed into 16-bit data types:
-
VK_FORMAT_R4G4B4A4_UNORM_PACK16 -
VK_FORMAT_B4G4R4A4_UNORM_PACK16 -
VK_FORMAT_R5G6B5_UNORM_PACK16 -
VK_FORMAT_B5G6R5_UNORM_PACK16 -
VK_FORMAT_R5G5B5A1_UNORM_PACK16 -
VK_FORMAT_B5G5R5A1_UNORM_PACK16 -
VK_FORMAT_A1R5G5B5_UNORM_PACK16
-
-
Packed into 32-bit data types:
-
VK_FORMAT_A8B8G8R8_UNORM_PACK32 -
VK_FORMAT_A8B8G8R8_SNORM_PACK32 -
VK_FORMAT_A8B8G8R8_USCALED_PACK32 -
VK_FORMAT_A8B8G8R8_SSCALED_PACK32 -
VK_FORMAT_A8B8G8R8_UINT_PACK32 -
VK_FORMAT_A8B8G8R8_SINT_PACK32 -
VK_FORMAT_A8B8G8R8_SRGB_PACK32 -
VK_FORMAT_A2R10G10B10_UNORM_PACK32 -
VK_FORMAT_A2R10G10B10_SNORM_PACK32 -
VK_FORMAT_A2R10G10B10_USCALED_PACK32 -
VK_FORMAT_A2R10G10B10_SSCALED_PACK32 -
VK_FORMAT_A2R10G10B10_UINT_PACK32 -
VK_FORMAT_A2R10G10B10_SINT_PACK32 -
VK_FORMAT_A2B10G10R10_UNORM_PACK32 -
VK_FORMAT_A2B10G10R10_SNORM_PACK32 -
VK_FORMAT_A2B10G10R10_USCALED_PACK32 -
VK_FORMAT_A2B10G10R10_SSCALED_PACK32 -
VK_FORMAT_A2B10G10R10_UINT_PACK32 -
VK_FORMAT_A2B10G10R10_SINT_PACK32 -
VK_FORMAT_B10G11R11_UFLOAT_PACK32 -
VK_FORMAT_E5B9G9R9_UFLOAT_PACK32 -
VK_FORMAT_X8_D24_UNORM_PACK32
-
Identification of Formats
A “format” is represented by a single enum value. The name of a format is usually built up by using the following pattern:
VK_FORMAT_{component-format|compression-scheme}_{numeric-format}
The component-format indicates either the size of the R, G, B, and A components (if they are present) in the case of a color format, or the size of the depth (D) and stencil (S) components (if they are present) in the case of a depth/stencil format (see below). An X indicates a component that is unused, but may be present for padding.
| Numeric format | Description |
|---|---|
|
The components are unsigned normalized values in the range [0,1] |
|
The components are signed normalized values in the range [-1,1] |
|
The components are unsigned integer values that get converted to floating-point in the range [0,2n-1] |
|
The components are signed integer values that get converted to floating-point in the range [-2n-1,2n-1-1] |
|
The components are unsigned integer values in the range [0,2n-1] |
|
The components are signed integer values in the range [-2n-1,2n-1-1] |
|
The components are unsigned floating-point numbers (used by packed, shared exponent, and some compressed formats) |
|
The components are signed floating-point numbers |
|
The R, G, and B components are unsigned normalized values that represent values using sRGB nonlinear encoding, while the A component (if one exists) is a regular unsigned normalized value |
The suffix _PACKnn indicates that the format is packed into an
underlying type with nn bits.
The suffix _mPACKnn is a short-hand that indicates that the format has
several components (which may or may not be stored in separate planes)
that are each packed into an underlying type with nn bits.
The suffix _BLOCK indicates that the format is a block-compressed
format, with the representation of multiple pixels encoded interdependently
within a region.
| Compression scheme | Description |
|---|---|
|
Block Compression. See Block-Compressed Image Formats. |
|
Ericsson Texture Compression. See ETC Compressed Image Formats. |
|
ETC2 Alpha Compression. See ETC Compressed Image Formats. |
|
Adaptive Scalable Texture Compression (LDR Profile). See ASTC Compressed Image Formats. |
For multi-planar images, the components in separate planes are separated
by underscores, and the number of planes is indicated by the addition of a
_2PLANE or _3PLANE suffix.
Similarly, the separate aspects of depth-stencil formats are separated by
underscores, although these are not considered separate planes.
Formats are suffixed by _422 to indicate that planes other than the
first are reduced in size by a factor of two horizontally or that the R and
B values appear at half the horizontal frequency of the G values, _420
to indicate that planes other than the first are reduced in size by a factor
of two both horizontally and vertically, and _444 for consistency to
indicate that all three planes of a three-planar image are the same size.
|
Note
No common format has a single plane containing both R and B channels but does not store these channels at reduced horizontal resolution. |
Representation
Color formats must be represented in memory in exactly the form indicated by the format’s name. This means that promoting one format to another with more bits per component and/or additional components must not occur for color formats. Depth/stencil formats have more relaxed requirements as discussed below. Each format has an element size, the number of bytes used to stored one element or one compressed block, with the value of the element size listed in VkFormat.
The representation of non-packed formats is that the first component specified in the name of the format is in the lowest memory addresses and the last component specified is in the highest memory addresses. See Byte mappings for non-packed/compressed color formats. The in-memory ordering of bytes within a component is determined by the host endianness.
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | ← Byte |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
R |
|
|||||||||||||||
R |
G |
|
||||||||||||||
R |
G |
B |
|
|||||||||||||
B |
G |
R |
|
|||||||||||||
R |
G |
B |
A |
|
||||||||||||
B |
G |
R |
A |
|
||||||||||||
G0 |
B |
G1 |
R |
|
||||||||||||
B |
G0 |
R |
G1 |
|
||||||||||||
R |
|
|||||||||||||||
R |
G |
|
||||||||||||||
R |
G |
B |
|
|||||||||||||
R |
G |
B |
A |
|
||||||||||||
G0 |
B |
G1 |
R |
|
||||||||||||
B |
G0 |
R |
G1 |
|
||||||||||||
R |
|
|||||||||||||||
R |
G |
|
||||||||||||||
R |
G |
B |
|
|||||||||||||
R |
G |
B |
A |
|
||||||||||||
R |
|
|||||||||||||||
R |
G |
|
||||||||||||||
|
||||||||||||||||
|
||||||||||||||||
Packed formats store multiple components within one underlying type. The bit representation is that the first component specified in the name of the format is in the most-significant bits and the last component specified is in the least-significant bits of the underlying type. The in-memory ordering of bytes comprising the underlying type is determined by the host endianness.
| Bit | |||||||
|---|---|---|---|---|---|---|---|
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
|
|||||||
R |
G |
||||||
3 |
2 |
1 |
0 |
3 |
2 |
1 |
0 |
| Bit | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
15 |
14 |
13 |
12 |
11 |
10 |
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
|
|||||||||||||||
R |
G |
B |
A |
||||||||||||
3 |
2 |
1 |
0 |
3 |
2 |
1 |
0 |
3 |
2 |
1 |
0 |
3 |
2 |
1 |
0 |
|
|||||||||||||||
B |
G |
R |
A |
||||||||||||
3 |
2 |
1 |
0 |
3 |
2 |
1 |
0 |
3 |
2 |
1 |
0 |
3 |
2 |
1 |
0 |
|
|||||||||||||||
R |
G |
B |
|||||||||||||
4 |
3 |
2 |
1 |
0 |
5 |
4 |
3 |
2 |
1 |
0 |
4 |
3 |
2 |
1 |
0 |
|
|||||||||||||||
B |
G |
R |
|||||||||||||
4 |
3 |
2 |
1 |
0 |
5 |
4 |
3 |
2 |
1 |
0 |
4 |
3 |
2 |
1 |
0 |
|
|||||||||||||||
R |
G |
B |
A |
||||||||||||
4 |
3 |
2 |
1 |
0 |
4 |
3 |
2 |
1 |
0 |
4 |
3 |
2 |
1 |
0 |
0 |
|
|||||||||||||||
B |
G |
R |
A |
||||||||||||
4 |
3 |
2 |
1 |
0 |
4 |
3 |
2 |
1 |
0 |
4 |
3 |
2 |
1 |
0 |
0 |
|
|||||||||||||||
A |
R |
G |
B |
||||||||||||
0 |
4 |
3 |
2 |
1 |
0 |
4 |
3 |
2 |
1 |
0 |
4 |
3 |
2 |
1 |
0 |
|
|||||||||||||||
R |
X |
||||||||||||||
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
5 |
4 |
3 |
2 |
1 |
0 |
|
|||||||||||||||
R |
X |
||||||||||||||
11 |
10 |
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
3 |
2 |
1 |
0 |
| Bit | |||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
31 |
30 |
29 |
28 |
27 |
26 |
25 |
24 |
23 |
22 |
21 |
20 |
19 |
18 |
17 |
16 |
15 |
14 |
13 |
12 |
11 |
10 |
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
|
|||||||||||||||||||||||||||||||
A |
B |
G |
R |
||||||||||||||||||||||||||||
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
|
|||||||||||||||||||||||||||||||
A |
R |
G |
B |
||||||||||||||||||||||||||||
1 |
0 |
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
|
|||||||||||||||||||||||||||||||
A |
B |
G |
R |
||||||||||||||||||||||||||||
1 |
0 |
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
|
|||||||||||||||||||||||||||||||
B |
G |
R |
|||||||||||||||||||||||||||||
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
10 |
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
10 |
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
|
|||||||||||||||||||||||||||||||
E |
B |
G |
R |
||||||||||||||||||||||||||||
4 |
3 |
2 |
1 |
0 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
|
|||||||||||||||||||||||||||||||
X |
D |
||||||||||||||||||||||||||||||
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
23 |
22 |
21 |
20 |
19 |
18 |
17 |
16 |
15 |
14 |
13 |
12 |
11 |
10 |
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
Depth/Stencil Formats
Depth/stencil formats are considered opaque and need not be stored in the exact number of bits per texel or component ordering indicated by the format enum. However, implementations must not substitute a different depth or stencil precision than that described in the format (e.g. D16 must not be implemented as D24 or D32).
Format Compatibility Classes
Uncompressed color formats are compatible with each other if they occupy the same number of bits per data element. Compressed color formats are compatible with each other if the only difference between them is the numerical type of the uncompressed pixels (e.g. signed vs. unsigned, or SRGB vs. UNORM encoding). Each depth/stencil format is only compatible with itself. In the following table, all the formats in the same row are compatible.
| Class | Formats |
|---|---|
8-bit |
|
16-bit |
|
24-bit |
|
32-bit |
|
32-bit G8B8G8R8 |
|
32-bit B8G8R8G8 |
|
48-bit |
|
64-bit |
|
64-bit R10G10B10A10 |
|
64-bit G10B10G10R10 |
|
64-bit B10G10R10G10 |
|
64-bit R12G12B12A12 |
|
64-bit G12B12G12R12 |
|
64-bit B12G12R12G12 |
|
64-bit G16B16G16R16 |
|
64-bit B16G16R16G16 |
|
96-bit |
|
128-bit |
|
192-bit |
|
256-bit |
|
BC1_RGB |
|
BC1_RGBA |
|
BC2 |
|
BC3 |
|
BC4 |
|
BC5 |
|
BC6H |
|
BC7 |
|
ETC2_RGB |
|
ETC2_RGBA |
|
ETC2_EAC_RGBA |
|
EAC_R |
|
EAC_RG |
|
ASTC_4x4 |
|
ASTC_5x4 |
|
ASTC_5x5 |
|
ASTC_6x5 |
|
ASTC_6x6 |
|
ASTC_8x5 |
|
ASTC_8x6 |
|
ASTC_8x8 |
|
ASTC_10x5 |
|
ASTC_10x6 |
|
ASTC_10x8 |
|
ASTC_10x10 |
|
ASTC_12x10 |
|
ASTC_12x12 |
|
D16 |
|
D24 |
|
D32 |
|
S8 |
|
D16S8 |
|
D24S8 |
|
D32S8 |
|
8-bit 3-plane 420 |
|
8-bit 2-plane 420 |
|
8-bit 3-plane 422 |
|
8-bit 2-plane 422 |
|
8-bit 3-plane 444 |
|
10-bit 3-plane 420 |
|
10-bit 2-plane 420 |
|
10-bit 3-plane 422 |
|
10-bit 2-plane 422 |
|
10-bit 3-plane 444 |
|
12-bit 3-plane 420 |
|
12-bit 2-plane 420 |
|
12-bit 3-plane 422 |
|
12-bit 2-plane 422 |
|
12-bit 3-plane 444 |
|
16-bit 3-plane 420 |
|
16-bit 2-plane 420 |
|
16-bit 3-plane 422 |
|
16-bit 2-plane 422 |
|
16-bit 3-plane 444 |
|
32.4.2. Format Properties
To query supported format features which are properties of the physical device, call:
void vkGetPhysicalDeviceFormatProperties(
VkPhysicalDevice physicalDevice,
VkFormat format,
VkFormatProperties* pFormatProperties);
-
physicalDeviceis the physical device from which to query the format properties. -
formatis the format whose properties are queried. -
pFormatPropertiesis a pointer to a VkFormatProperties structure in which physical device properties forformatare returned.
The VkFormatProperties structure is defined as:
typedef struct VkFormatProperties {
VkFormatFeatureFlags linearTilingFeatures;
VkFormatFeatureFlags optimalTilingFeatures;
VkFormatFeatureFlags bufferFeatures;
} VkFormatProperties;
-
linearTilingFeaturesis a bitmask of VkFormatFeatureFlagBits specifying features supported by images created with atilingparameter ofVK_IMAGE_TILING_LINEAR. -
optimalTilingFeaturesis a bitmask of VkFormatFeatureFlagBits specifying features supported by images created with atilingparameter ofVK_IMAGE_TILING_OPTIMAL. -
bufferFeaturesis a bitmask of VkFormatFeatureFlagBits specifying features supported by buffers.
|
Note
If no format feature flags are supported, the format itself is not supported, and images of that format cannot be created. |
If format is a block-compression format, then buffers must not
support any features for the format.
Bits which can be set in the VkFormatProperties features
linearTilingFeatures, optimalTilingFeatures, and
bufferFeatures are:
typedef enum VkFormatFeatureFlagBits {
VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT = 0x00000001,
VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT = 0x00000002,
VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT = 0x00000004,
VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BIT = 0x00000008,
VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT = 0x00000010,
VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_ATOMIC_BIT = 0x00000020,
VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT = 0x00000040,
VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT = 0x00000080,
VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT = 0x00000100,
VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT = 0x00000200,
VK_FORMAT_FEATURE_BLIT_SRC_BIT = 0x00000400,
VK_FORMAT_FEATURE_BLIT_DST_BIT = 0x00000800,
VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT = 0x00001000,
VK_FORMAT_FEATURE_TRANSFER_SRC_BIT = 0x00004000,
VK_FORMAT_FEATURE_TRANSFER_DST_BIT = 0x00008000,
VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT = 0x00020000,
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BIT = 0x00040000,
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_SEPARATE_RECONSTRUCTION_FILTER_BIT = 0x00080000,
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT = 0x00100000,
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_FORCEABLE_BIT = 0x00200000,
VK_FORMAT_FEATURE_DISJOINT_BIT = 0x00400000,
VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT = 0x00800000,
VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_IMG = 0x00002000,
VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_MINMAX_BIT_EXT = 0x00010000,
VK_FORMAT_FEATURE_TRANSFER_SRC_BIT_KHR = VK_FORMAT_FEATURE_TRANSFER_SRC_BIT,
VK_FORMAT_FEATURE_TRANSFER_DST_BIT_KHR = VK_FORMAT_FEATURE_TRANSFER_DST_BIT,
VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT_KHR = VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT,
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BIT_KHR = VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BIT,
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_SEPARATE_RECONSTRUCTION_FILTER_BIT_KHR = VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_SEPARATE_RECONSTRUCTION_FILTER_BIT,
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT_KHR = VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT,
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_FORCEABLE_BIT_KHR = VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_FORCEABLE_BIT,
VK_FORMAT_FEATURE_DISJOINT_BIT_KHR = VK_FORMAT_FEATURE_DISJOINT_BIT,
VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT_KHR = VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT,
} VkFormatFeatureFlagBits;
The following bits may be set in linearTilingFeatures and
optimalTilingFeatures, specifying that the features are supported by
images or image views created with the queried
vkGetPhysicalDeviceFormatProperties::format:
-
VK_FORMAT_FEATURE_SAMPLED_IMAGE_BITspecifies that an image view can be sampled from. -
VK_FORMAT_FEATURE_STORAGE_IMAGE_BITspecifies that an image view can be used as a storage images. -
VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BITspecifies that an image view can be used as storage image that supports atomic operations. -
VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BITspecifies that an image view can be used as a framebuffer color attachment and as an input attachment. -
VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BITspecifies that an image view can be used as a framebuffer color attachment that supports blending and as an input attachment. -
VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BITspecifies that an image view can be used as a framebuffer depth/stencil attachment and as an input attachment. -
VK_FORMAT_FEATURE_BLIT_SRC_BITspecifies that an image can be used assrcImagefor thevkCmdBlitImagecommand. -
VK_FORMAT_FEATURE_BLIT_DST_BITspecifies that an image can be used asdstImagefor thevkCmdBlitImagecommand. -
VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BITspecifies that ifVK_FORMAT_FEATURE_SAMPLED_IMAGE_BITis also set, an image view can be used with a sampler that has either ofmagFilterorminFilterset toVK_FILTER_LINEAR, ormipmapModeset toVK_SAMPLER_MIPMAP_MODE_LINEAR. IfVK_FORMAT_FEATURE_BLIT_SRC_BITis also set, an image can be used as thesrcImageto vkCmdBlitImage with afilterofVK_FILTER_LINEAR. This bit must only be exposed for formats that also support theVK_FORMAT_FEATURE_SAMPLED_IMAGE_BITorVK_FORMAT_FEATURE_BLIT_SRC_BIT.If the format being queried is a depth/stencil format, this bit only specifies that the depth aspect (not the stencil aspect) of an image of this format supports linear filtering, and that linear filtering of the depth aspect is supported whether depth compare is enabled in the sampler or not. If this bit is not present, linear filtering with depth compare disabled is unsupported and linear filtering with depth compare enabled is supported, but may compute the filtered value in an implementation-dependent manner which differs from the normal rules of linear filtering. The resulting value must be in the range [0,1] and should be proportional to, or a weighted average of, the number of comparison passes or failures.
-
VK_FORMAT_FEATURE_TRANSFER_SRC_BITspecifies that an image can be used as a source image for copy commands. -
VK_FORMAT_FEATURE_TRANSFER_DST_BITspecifies that an image can be used as a destination image for copy commands and clear commands. -
VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_MINMAX_BIT_EXTspecifiesVkImagecan be used as a sampled image with a min or max VkSamplerReductionModeEXT. This bit must only be exposed for formats that also support theVK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT. -
VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_IMGspecifies thatVkImagecan be used with a sampler that has either ofmagFilterorminFilterset toVK_FILTER_CUBIC_IMG, or be the source image for a blit withfilterset toVK_FILTER_CUBIC_IMG. This bit must only be exposed for formats that also support theVK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT. If the format being queried is a depth/stencil format, this only specifies that the depth aspect is cubic filterable. -
VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BITspecifies that an application can define a sampler Y’CBCR conversion using this format as a source, and that an image of this format can be used with aVkSamplerYcbcrConversionCreateInfoxChromaOffsetand/oryChromaOffsetofVK_CHROMA_LOCATION_MIDPOINT. Otherwise bothxChromaOffsetandyChromaOffsetmust beVK_CHROMA_LOCATION_COSITED_EVEN. If a format does not incorporate chroma downsampling (it is not a “422” or “420” format) but the implementation supports sampler Y’CBCR conversion for this format, the implementation must setVK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT. -
VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BITspecifies that an application can define a sampler Y’CBCR conversion using this format as a source, and that an image of this format can be used with aVkSamplerYcbcrConversionCreateInfoxChromaOffsetand/oryChromaOffsetofVK_CHROMA_LOCATION_COSITED_EVEN. Otherwise bothxChromaOffsetandyChromaOffsetmust beVK_CHROMA_LOCATION_MIDPOINT. If neitherVK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BITnorVK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BITis set, the application must not define a sampler Y’CBCR conversion using this format as a source. -
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BITspecifies that the format can do linear sampler filtering (min/magFilter) whilst sampler Y’CBCR conversion is enabled. -
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_SEPARATE_RECONSTRUCTION_FILTER_BITspecifies that the format can have different chroma, min, and mag filters. -
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BITspecifies that reconstruction is explicit, as described in Chroma Reconstruction. If this bit is not present, reconstruction is implicit by default. -
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_FORCEABLE_BITspecifies that reconstruction can be forcibly made explicit by setting VkSamplerYcbcrConversionCreateInfo::forceExplicitReconstructiontoVK_TRUE. -
VK_FORMAT_FEATURE_DISJOINT_BITspecifies that a multi-planar image can have theVK_IMAGE_CREATE_DISJOINT_BITset during image creation. An implementation must not setVK_FORMAT_FEATURE_DISJOINT_BITfor single-plane formats.
The following bits may be set in bufferFeatures, specifying that the
features are supported by buffers or buffer
views created with the queried
vkGetPhysicalDeviceProperties::format:
-
VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BITspecifies that the format can be used to create a buffer view that can be bound to aVK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFERdescriptor. -
VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BITspecifies that the format can be used to create a buffer view that can be bound to aVK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFERdescriptor. -
VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_ATOMIC_BITspecifies that atomic operations are supported onVK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFERwith this format. -
VK_FORMAT_FEATURE_VERTEX_BUFFER_BITspecifies that the format can be used as a vertex attribute format (VkVertexInputAttributeDescription::format).
typedef VkFlags VkFormatFeatureFlags;
VkFormatFeatureFlags is a bitmask type for setting a mask of zero or
more VkFormatFeatureFlagBits.
To query supported format features which are properties of the physical device, call:
void vkGetPhysicalDeviceFormatProperties2(
VkPhysicalDevice physicalDevice,
VkFormat format,
VkFormatProperties2* pFormatProperties);
or the equivalent command
void vkGetPhysicalDeviceFormatProperties2KHR(
VkPhysicalDevice physicalDevice,
VkFormat format,
VkFormatProperties2* pFormatProperties);
-
physicalDeviceis the physical device from which to query the format properties. -
formatis the format whose properties are queried. -
pFormatPropertiesis a pointer to a VkFormatProperties2 structure in which physical device properties forformatare returned.
vkGetPhysicalDeviceFormatProperties2 behaves similarly to
vkGetPhysicalDeviceFormatProperties, with the ability to return
extended information in a pNext chain of output structures.
The VkFormatProperties2 structure is defined as:
typedef struct VkFormatProperties2 {
VkStructureType sType;
void* pNext;
VkFormatProperties formatProperties;
} VkFormatProperties2;
or the equivalent
typedef VkFormatProperties2 VkFormatProperties2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
formatPropertiesis a structure of type VkFormatProperties describing features supported by the requested format.
32.4.3. Required Format Support
Implementations must support at least the following set of features on the listed formats. For images, these features must be supported for every VkImageType (including arrayed and cube variants) unless otherwise noted. These features are supported on existing formats without needing to advertise an extension or needing to explicitly enable them. Support for additional functionality beyond the requirements listed here is queried using the vkGetPhysicalDeviceFormatProperties command.
The following tables show which feature bits must be supported for each
format.
Formats that are required to support
VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT must also support
VK_FORMAT_FEATURE_TRANSFER_SRC_BIT and
VK_FORMAT_FEATURE_TRANSFER_DST_BIT.
✓ |
This feature must be supported on the named format |
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VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_IMG must be
supported for the following formats:
-
VK_FORMAT_R4G4_UNORM_PACK8 -
VK_FORMAT_R4G4B4A4_UNORM_PACK16 -
VK_FORMAT_B4G4R4A4_UNORM_PACK16 -
VK_FORMAT_R5G6B5_UNORM_PACK16 -
VK_FORMAT_B5G6R5_UNORM_PACK16 -
VK_FORMAT_R5G5B5A1_UNORM_PACK16 -
VK_FORMAT_B5G5R5A1_UNORM_PACK16 -
VK_FORMAT_A1R5G5B5_UNORM_PACK16 -
VK_FORMAT_R8_UNORM -
VK_FORMAT_R8_SNORM -
VK_FORMAT_R8_SRGB -
VK_FORMAT_R8G8_UNORM -
VK_FORMAT_R8G8_SNORM -
VK_FORMAT_R8G8_SRGB -
VK_FORMAT_R8G8B8_UNORM -
VK_FORMAT_R8G8B8_SNORM -
VK_FORMAT_R8G8B8_SRGB -
VK_FORMAT_B8G8R8_UNORM -
VK_FORMAT_B8G8R8_SNORM -
VK_FORMAT_B8G8R8_SRGB -
VK_FORMAT_R8G8B8A8_UNORM -
VK_FORMAT_R8G8B8A8_SNORM -
VK_FORMAT_R8G8B8A8_SRGB -
VK_FORMAT_B8G8R8A8_UNORM -
VK_FORMAT_B8G8R8A8_SNORM -
VK_FORMAT_B8G8R8A8_SRGB -
VK_FORMAT_A8B8G8R8_UNORM_PACK32 -
VK_FORMAT_A8B8G8R8_SNORM_PACK32 -
VK_FORMAT_A8B8G8R8_USCALED_PACK32 -
VK_FORMAT_A8B8G8R8_SSCALED_PACK32 -
VK_FORMAT_A8B8G8R8_UINT_PACK32 -
VK_FORMAT_A8B8G8R8_SINT_PACK32 -
VK_FORMAT_A8B8G8R8_SRGB_PACK32
If ETC2 compressed formats are supported, the following additional formats
must support VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_IMG:
-
VK_FORMAT_ETC2_R8G8B8_UNORM_BLOCK -
VK_FORMAT_ETC2_R8G8B8_SRGB_BLOCK -
VK_FORMAT_ETC2_R8G8B8A1_UNORM_BLOCK -
VK_FORMAT_ETC2_R8G8B8A1_SRGB_BLOCK -
VK_FORMAT_ETC2_R8G8B8A8_UNORM_BLOCK -
VK_FORMAT_ETC2_R8G8B8A8_SRGB_BLOCK
To be used with VkImageView with subresourceRange.aspectMask =
VK_IMAGE_ASPECT_COLOR_BIT, sampler
Y’CBCR conversion must be enabled for the following formats:
Format must be supported if VkPhysicalDeviceSamplerYcbcrConversionFeatures is enabled |
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32.5. Additional Image Capabilities
In addition to the minimum capabilities described in the previous sections (Limits and Formats), implementations may support additional capabilities for certain types of images. For example, larger dimensions or additional sample counts for certain image types, or additional capabilities for linear tiling format images.
To query additional capabilities specific to image types, call:
VkResult vkGetPhysicalDeviceImageFormatProperties(
VkPhysicalDevice physicalDevice,
VkFormat format,
VkImageType type,
VkImageTiling tiling,
VkImageUsageFlags usage,
VkImageCreateFlags flags,
VkImageFormatProperties* pImageFormatProperties);
-
physicalDeviceis the physical device from which to query the image capabilities. -
formatis a VkFormat value specifying the image format, corresponding to VkImageCreateInfo::format. -
typeis a VkImageType value specifying the image type, corresponding to VkImageCreateInfo::imageType. -
tilingis a VkImageTiling value specifying the image tiling, corresponding to VkImageCreateInfo::tiling. -
usageis a bitmask of VkImageUsageFlagBits specifying the intended usage of the image, corresponding to VkImageCreateInfo::usage. -
flagsis a bitmask of VkImageCreateFlagBits specifying additional parameters of the image, corresponding to VkImageCreateInfo::flags. -
pImageFormatPropertiespoints to an instance of the VkImageFormatProperties structure in which capabilities are returned.
The format, type, tiling, usage, and flags
parameters correspond to parameters that would be consumed by
vkCreateImage (as members of VkImageCreateInfo).
If format is not a supported image format, or if the combination of
format, type, tiling, usage, and flags is not
supported for images, then vkGetPhysicalDeviceImageFormatProperties
returns VK_ERROR_FORMAT_NOT_SUPPORTED.
The limitations on an image format that are reported by
vkGetPhysicalDeviceImageFormatProperties have the following property:
if usage1 and usage2 of type VkImageUsageFlags are such that
the bits set in usage1 are a subset of the bits set in usage2, and
flags1 and flags2 of type VkImageCreateFlags are such that
the bits set in flags1 are a subset of the bits set in flags2,
then the limitations for usage1 and flags1 must be no more strict
than the limitations for usage2 and flags2, for all values of
format, type, and tiling.
The VkImageFormatProperties structure is defined as:
typedef struct VkImageFormatProperties {
VkExtent3D maxExtent;
uint32_t maxMipLevels;
uint32_t maxArrayLayers;
VkSampleCountFlags sampleCounts;
VkDeviceSize maxResourceSize;
} VkImageFormatProperties;
-
maxExtentare the maximum image dimensions. See the Allowed Extent Values section below for how these values are constrained bytype. -
maxMipLevelsis the maximum number of mipmap levels.maxMipLevelsmust be equal to ⌈log2(max(width,height,depth))⌉ + 1, wherewidth,height, anddepthare taken from the corresponding members ofmaxExtent, except when one of the following conditions is true, in which case it may instead be1:-
vkGetPhysicalDeviceImageFormatProperties::tilingwasVK_IMAGE_TILING_LINEAR -
the VkPhysicalDeviceImageFormatInfo2::
pNextchain included an instance of VkPhysicalDeviceExternalImageFormatInfo with a handle type included in thehandleTypesmember for which mipmap image support is not required
-
-
maxArrayLayersis the maximum number of array layers.maxArrayLayersmust either be equal to 1 or be greater than or equal to themaxImageArrayLayersmember of VkPhysicalDeviceLimits. A value of 1 is valid only iftilingisVK_IMAGE_TILING_LINEARor iftypeisVK_IMAGE_TYPE_3D. -
sampleCountsis a bitmask of VkSampleCountFlagBits specifying all the supported sample counts for this image as described below. -
maxResourceSizeis an upper bound on the total image size in bytes, inclusive of all image subresources. Implementations may have an address space limit on total size of a resource, which is advertised by this property.maxResourceSizemust be at least 231.
|
Note
There is no mechanism to query the size of an image before creating it, to
compare that size against |
If the combination of parameters to
vkGetPhysicalDeviceImageFormatProperties is not supported by the
implementation for use in vkCreateImage, then all members of
VkImageFormatProperties will be filled with zero.
|
Note
Filling |
To determine the image capabilities compatible with an external memory handle type, call:
VkResult vkGetPhysicalDeviceExternalImageFormatPropertiesNV(
VkPhysicalDevice physicalDevice,
VkFormat format,
VkImageType type,
VkImageTiling tiling,
VkImageUsageFlags usage,
VkImageCreateFlags flags,
VkExternalMemoryHandleTypeFlagsNV externalHandleType,
VkExternalImageFormatPropertiesNV* pExternalImageFormatProperties);
-
physicalDeviceis the physical device from which to query the image capabilities -
formatis the image format, corresponding to VkImageCreateInfo::format. -
typeis the image type, corresponding to VkImageCreateInfo::imageType. -
tilingis the image tiling, corresponding to VkImageCreateInfo::tiling. -
usageis the intended usage of the image, corresponding to VkImageCreateInfo::usage. -
flagsis a bitmask describing additional parameters of the image, corresponding to VkImageCreateInfo::flags. -
externalHandleTypeis either one of the bits from VkExternalMemoryHandleTypeFlagBitsNV, or 0. -
pExternalImageFormatPropertiespoints to an instance of the VkExternalImageFormatPropertiesNV structure in which capabilities are returned.
If externalHandleType is 0,
pExternalImageFormatProperties::imageFormatProperties will return the
same values as a call to vkGetPhysicalDeviceImageFormatProperties, and
the other members of pExternalImageFormatProperties will all be 0.
Otherwise, they are filled in as described for
VkExternalImageFormatPropertiesNV.
The VkExternalImageFormatPropertiesNV structure is defined as:
typedef struct VkExternalImageFormatPropertiesNV {
VkImageFormatProperties imageFormatProperties;
VkExternalMemoryFeatureFlagsNV externalMemoryFeatures;
VkExternalMemoryHandleTypeFlagsNV exportFromImportedHandleTypes;
VkExternalMemoryHandleTypeFlagsNV compatibleHandleTypes;
} VkExternalImageFormatPropertiesNV;
-
imageFormatPropertieswill be filled in as when calling vkGetPhysicalDeviceImageFormatProperties, but the values returned may vary depending on the external handle type requested. -
externalMemoryFeaturesis a bitmask of VkExternalMemoryFeatureFlagBitsNV, indicating properties of the external memory handle type (vkGetPhysicalDeviceExternalImageFormatPropertiesNV::externalHandleType) being queried, or 0 if the external memory handle type is 0. -
exportFromImportedHandleTypesis a bitmask of VkExternalMemoryHandleTypeFlagBitsNV containing a bit set for every external handle type that may be used to create memory from which the handles of the type specified in vkGetPhysicalDeviceExternalImageFormatPropertiesNV::externalHandleTypecan be exported, or 0 if the external memory handle type is 0. -
compatibleHandleTypesis a bitmask of VkExternalMemoryHandleTypeFlagBitsNV containing a bit set for every external handle type that may be specified simultaneously with the handle type specified by vkGetPhysicalDeviceExternalImageFormatPropertiesNV::externalHandleTypewhen calling vkAllocateMemory, or 0 if the external memory handle type is 0.compatibleHandleTypeswill always contain vkGetPhysicalDeviceExternalImageFormatPropertiesNV::externalHandleType
Bits which can be set in
VkExternalMemoryFeatureFlagBitsNV::externalMemoryFeatures,
indicating properties of the external memory handle type, are:
typedef enum VkExternalMemoryFeatureFlagBitsNV {
VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT_NV = 0x00000001,
VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT_NV = 0x00000002,
VK_EXTERNAL_MEMORY_FEATURE_IMPORTABLE_BIT_NV = 0x00000004,
} VkExternalMemoryFeatureFlagBitsNV;
-
VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT_NVspecifies that external memory of the specified type must be created as a dedicated allocation when used in the manner specified. -
VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT_NVspecifies that the implementation supports exporting handles of the specified type. -
VK_EXTERNAL_MEMORY_FEATURE_IMPORTABLE_BIT_NVspecifies that the implementation supports importing handles of the specified type.
typedef VkFlags VkExternalMemoryFeatureFlagsNV;
VkExternalMemoryFeatureFlagsNV is a bitmask type for setting a mask of
zero or more VkExternalMemoryFeatureFlagBitsNV.
To query additional capabilities specific to image types, call:
VkResult vkGetPhysicalDeviceImageFormatProperties2(
VkPhysicalDevice physicalDevice,
const VkPhysicalDeviceImageFormatInfo2* pImageFormatInfo,
VkImageFormatProperties2* pImageFormatProperties);
or the equivalent command
VkResult vkGetPhysicalDeviceImageFormatProperties2KHR(
VkPhysicalDevice physicalDevice,
const VkPhysicalDeviceImageFormatInfo2* pImageFormatInfo,
VkImageFormatProperties2* pImageFormatProperties);
-
physicalDeviceis the physical device from which to query the image capabilities. -
pImageFormatInfopoints to an instance of the VkPhysicalDeviceImageFormatInfo2 structure, describing the parameters that would be consumed by vkCreateImage. -
pImageFormatPropertiespoints to an instance of the VkImageFormatProperties2 structure in which capabilities are returned.
vkGetPhysicalDeviceImageFormatProperties2 behaves similarly to
vkGetPhysicalDeviceImageFormatProperties, with the ability to return
extended information in a pNext chain of output structures.
The VkPhysicalDeviceImageFormatInfo2 structure is defined as:
typedef struct VkPhysicalDeviceImageFormatInfo2 {
VkStructureType sType;
const void* pNext;
VkFormat format;
VkImageType type;
VkImageTiling tiling;
VkImageUsageFlags usage;
VkImageCreateFlags flags;
} VkPhysicalDeviceImageFormatInfo2;
or the equivalent
typedef VkPhysicalDeviceImageFormatInfo2 VkPhysicalDeviceImageFormatInfo2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. ThepNextchain ofVkPhysicalDeviceImageFormatInfo2is used to provide additional image parameters tovkGetPhysicalDeviceImageFormatProperties2. -
formatis a VkFormat value indicating the image format, corresponding to VkImageCreateInfo::format. -
typeis a VkImageType value indicating the image type, corresponding to VkImageCreateInfo::imageType. -
tilingis a VkImageTiling value indicating the image tiling, corresponding to VkImageCreateInfo::tiling. -
usageis a bitmask of VkImageUsageFlagBits indicating the intended usage of the image, corresponding to VkImageCreateInfo::usage. -
flagsis a bitmask of VkImageCreateFlagBits indicating additional parameters of the image, corresponding to VkImageCreateInfo::flags.
The members of VkPhysicalDeviceImageFormatInfo2 correspond to the
arguments to vkGetPhysicalDeviceImageFormatProperties, with
sType and pNext added for extensibility.
The VkImageFormatProperties2 structure is defined as:
typedef struct VkImageFormatProperties2 {
VkStructureType sType;
void* pNext;
VkImageFormatProperties imageFormatProperties;
} VkImageFormatProperties2;
or the equivalent
typedef VkImageFormatProperties2 VkImageFormatProperties2KHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. ThepNextchain ofVkImageFormatProperties2is used to allow the specification of additional capabilities to be returned fromvkGetPhysicalDeviceImageFormatProperties2. -
imageFormatPropertiesis an instance of a VkImageFormatProperties structure in which capabilities are returned.
If the combination of parameters to
vkGetPhysicalDeviceImageFormatProperties2 is not supported by the
implementation for use in vkCreateImage, then all members of
imageFormatProperties will be filled with zero.
|
Note
Filling |
To determine if texture gather functions that take explicit LOD and/or bias
argument values can be used with a given image format, add
VkImageFormatProperties2 to the pNext chain of the
VkPhysicalDeviceImageFormatInfo2 structure and
VkTextureLODGatherFormatPropertiesAMD to the pNext chain of the
VkImageFormatProperties2 structure.
The VkTextureLODGatherFormatPropertiesAMD structure is defined as:
typedef struct VkTextureLODGatherFormatPropertiesAMD {
VkStructureType sType;
void* pNext;
VkBool32 supportsTextureGatherLODBiasAMD;
} VkTextureLODGatherFormatPropertiesAMD;
-
sTypeis the type of this structure. -
pNextisNULL. -
supportsTextureGatherLODBiasAMDtells if the image format can be used with texture gather bias/LOD functions, as introduced by theVK_AMD_texture_gather_bias_lodextension. This field is set by the implementation. User-specified value is ignored.
To determine the image capabilities compatible with an external memory
handle type, add VkPhysicalDeviceExternalImageFormatInfo to the
pNext chain of the VkPhysicalDeviceImageFormatInfo2 structure
and VkExternalImageFormatProperties to the pNext chain of the
VkImageFormatProperties2 structure.
The VkPhysicalDeviceExternalImageFormatInfo structure is defined as:
typedef struct VkPhysicalDeviceExternalImageFormatInfo {
VkStructureType sType;
const void* pNext;
VkExternalMemoryHandleTypeFlagBits handleType;
} VkPhysicalDeviceExternalImageFormatInfo;
or the equivalent
typedef VkPhysicalDeviceExternalImageFormatInfo VkPhysicalDeviceExternalImageFormatInfoKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
handleTypeis a VkExternalMemoryHandleTypeFlagBits value specifying the memory handle type that will be used with the memory associated with the image.
If handleType is 0, vkGetPhysicalDeviceImageFormatProperties2
will behave as if VkPhysicalDeviceExternalImageFormatInfo was not
present, and VkExternalImageFormatProperties will be ignored.
If handleType is not compatible with the format, type,
tiling, usage, and flags specified in
VkPhysicalDeviceImageFormatInfo2, then
vkGetPhysicalDeviceImageFormatProperties2 returns
VK_ERROR_FORMAT_NOT_SUPPORTED.
Possible values of
VkPhysicalDeviceExternalImageFormatInfo::handleType, specifying
an external memory handle type, are:
typedef enum VkExternalMemoryHandleTypeFlagBits {
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_FD_BIT = 0x00000001,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT = 0x00000002,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT = 0x00000004,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT = 0x00000008,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_KMT_BIT = 0x00000010,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_HEAP_BIT = 0x00000020,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT = 0x00000040,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_DMA_BUF_BIT_EXT = 0x00000200,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID = 0x00000400,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_ALLOCATION_BIT_EXT = 0x00000080,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_MAPPED_FOREIGN_MEMORY_BIT_EXT = 0x00000100,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_FD_BIT_KHR = VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_FD_BIT,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_KHR = VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT_KHR = VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT_KHR = VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_KMT_BIT_KHR = VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_KMT_BIT,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_HEAP_BIT_KHR = VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_HEAP_BIT,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT_KHR = VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT,
} VkExternalMemoryHandleTypeFlagBits;
or the equivalent
typedef VkExternalMemoryHandleTypeFlagBits VkExternalMemoryHandleTypeFlagBitsKHR;
-
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_FD_BITspecifies a POSIX file descriptor handle that has only limited valid usage outside of Vulkan and other compatible APIs. It must be compatible with the POSIX system callsdup,dup2,close, and the non-standard system calldup3. Additionally, it must be transportable over a socket using anSCM_RIGHTScontrol message. It owns a reference to the underlying memory resource represented by its Vulkan memory object. -
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BITspecifies an NT handle that has only limited valid usage outside of Vulkan and other compatible APIs. It must be compatible with the functionsDuplicateHandle,CloseHandle,CompareObjectHandles,GetHandleInformation, andSetHandleInformation. It owns a reference to the underlying memory resource represented by its Vulkan memory object. -
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_KMT_BITspecifies a global share handle that has only limited valid usage outside of Vulkan and other compatible APIs. It is not compatible with any native APIs. It does not own a reference to the underlying memory resource represented its Vulkan memory object, and will therefore become invalid when all Vulkan memory objects associated with it are destroyed. -
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BITspecifies an NT handle returned byIDXGIResource1::CreateSharedHandlereferring to a Direct3D 10 or 11 texture resource. It owns a reference to the memory used by the Direct3D resource. -
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_KMT_BITspecifies a global share handle returned byIDXGIResource::GetSharedHandlereferring to a Direct3D 10 or 11 texture resource. It does not own a reference to the underlying Direct3D resource, and will therefore become invalid when all Vulkan memory objects and Direct3D resources associated with it are destroyed. -
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_HEAP_BITspecifies an NT handle returned byID3D12Device::CreateSharedHandlereferring to a Direct3D 12 heap resource. It owns a reference to the resources used by the Direct3D heap. -
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BITspecifies an NT handle returned byID3D12Device::CreateSharedHandlereferring to a Direct3D 12 committed resource. It owns a reference to the memory used by the Direct3D resource. -
VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_ALLOCATION_BIT_EXTspecifies a host pointer returned by a host memory allocation command. It does not own a reference to the underlying memory resource, and will therefore become invalid if the host memory is freed. -
VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_MAPPED_FOREIGN_MEMORY_BIT_EXTspecifies a host pointer to host mapped foreign memory. It does not own a reference to the underlying memory resource, and will therefore become invalid if the foreign memory is unmapped or otherwise becomes no longer available. -
VK_EXTERNAL_MEMORY_HANDLE_TYPE_DMA_BUF_BIT_EXTis a file descriptor for a Linux dma_buf. It owns a reference to the underlying memory resource represented by its Vulkan memory object. -
VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROIDspecifies anAHardwareBufferobject defined by the Android NDK. See Android Hardware Buffers for more details of this handle type.
Some external memory handle types can only be shared within the same underlying physical device and/or the same driver version, as defined in the following table:
Handle type |
|
|
|
Must match |
Must match |
|
Must match |
Must match |
|
Must match |
Must match |
|
Must match |
Must match |
|
Must match |
Must match |
|
Must match |
Must match |
|
Must match |
Must match |
|
No restriction |
No restriction |
|
No restriction |
No restriction |
|
No restriction |
No restriction |
|
No restriction |
No restriction |
|
Note
The above table does not restrict the drivers and devices with which
|
|
Note
Even though the above table does not restrict the drivers and devices with
which |
typedef VkFlags VkExternalMemoryHandleTypeFlags;
or the equivalent
typedef VkExternalMemoryHandleTypeFlags VkExternalMemoryHandleTypeFlagsKHR;
VkExternalMemoryHandleTypeFlags is a bitmask type for setting a mask
of zero or more VkExternalMemoryHandleTypeFlagBits.
The VkExternalImageFormatProperties structure is defined as:
typedef struct VkExternalImageFormatProperties {
VkStructureType sType;
void* pNext;
VkExternalMemoryProperties externalMemoryProperties;
} VkExternalImageFormatProperties;
or the equivalent
typedef VkExternalImageFormatProperties VkExternalImageFormatPropertiesKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
externalMemoryPropertiesis an instance of the VkExternalMemoryProperties structure specifying various capabilities of the external handle type when used with the specified image creation parameters.
The VkExternalMemoryProperties structure is defined as:
typedef struct VkExternalMemoryProperties {
VkExternalMemoryFeatureFlags externalMemoryFeatures;
VkExternalMemoryHandleTypeFlags exportFromImportedHandleTypes;
VkExternalMemoryHandleTypeFlags compatibleHandleTypes;
} VkExternalMemoryProperties;
or the equivalent
typedef VkExternalMemoryProperties VkExternalMemoryPropertiesKHR;
-
externalMemoryFeaturesis a bitmask of VkExternalMemoryFeatureFlagBits specifying the features ofhandleType. -
exportFromImportedHandleTypesis a bitmask of VkExternalMemoryHandleTypeFlagBits specifying which types of imported handlehandleTypecan be exported from. -
compatibleHandleTypesis a bitmask of VkExternalMemoryHandleTypeFlagBits specifying handle types which can be specified at the same time ashandleTypewhen creating an image compatible with external memory.
compatibleHandleTypes must include at least handleType.
Inclusion of a handle type in compatibleHandleTypes does not imply the
values returned in VkImageFormatProperties2 will be the same when
VkPhysicalDeviceExternalImageFormatInfo::handleType is set to
that type.
The application is responsible for querying the capabilities of all handle
types intended for concurrent use in a single image and intersecting them to
obtain the compatible set of capabilities.
Bits which may be set in
VkExternalMemoryProperties::externalMemoryFeatures, specifying
features of an external memory handle type, are:
typedef enum VkExternalMemoryFeatureFlagBits {
VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT = 0x00000001,
VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT = 0x00000002,
VK_EXTERNAL_MEMORY_FEATURE_IMPORTABLE_BIT = 0x00000004,
VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT_KHR = VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT,
VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT_KHR = VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT,
VK_EXTERNAL_MEMORY_FEATURE_IMPORTABLE_BIT_KHR = VK_EXTERNAL_MEMORY_FEATURE_IMPORTABLE_BIT,
} VkExternalMemoryFeatureFlagBits;
or the equivalent
typedef VkExternalMemoryFeatureFlagBits VkExternalMemoryFeatureFlagBitsKHR;
-
VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BITspecifies that images or buffers created with the specified parameters and handle type must use the mechanisms defined in theVK_NV_dedicated_allocationextension to create (or import) a dedicated allocation for the image or buffer. -
VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BITspecifies that handles of this type can be exported from Vulkan memory objects. -
VK_INTERNAL_MEMORY_FEATURE_IMPORTABLE_BITspecifies that handles of this type can be imported as Vulkan memory objects.
Because their semantics in external APIs roughly align with that of an image
or buffer with a dedicated allocation in Vulkan, implementations are
required to report VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT for
the following external handle types:
-
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT -
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_KMT_BIT -
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT -
VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROIDfor images only
Implementations must not report
VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT for buffers with
external handle type
VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID.
typedef VkFlags VkExternalMemoryFeatureFlags;
or the equivalent
typedef VkExternalMemoryFeatureFlags VkExternalMemoryFeatureFlagsKHR;
VkExternalMemoryFeatureFlags is a bitmask type for setting a mask of
zero or more VkExternalMemoryFeatureFlagBits.
To determine the number of combined image samplers required to support a
multi-planar format, add VkSamplerYcbcrConversionImageFormatProperties
to the pNext chain of the VkImageFormatProperties2 structure in
a call to vkGetPhysicalDeviceImageFormatProperties2.
The VkSamplerYcbcrConversionImageFormatProperties structure is defined
as:
typedef struct VkSamplerYcbcrConversionImageFormatProperties {
VkStructureType sType;
void* pNext;
uint32_t combinedImageSamplerDescriptorCount;
} VkSamplerYcbcrConversionImageFormatProperties;
or the equivalent
typedef VkSamplerYcbcrConversionImageFormatProperties VkSamplerYcbcrConversionImageFormatPropertiesKHR;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
combinedImageSamplerDescriptorCountis the number of combined image sampler descriptors that the implementation uses to access the format.
combinedImageSamplerDescriptorCount affects only the count towards the
maxDescriptorSetSamplers, maxDescriptorSetSampledImages,
maxPerStageDescriptorSamplers, and
maxPerStageDescriptorSampledImages limits, and does not affect binding
numbers in the VkDescriptorSetLayoutBinding.
combinedImageSamplerDescriptorCount is a number between 1 and the
number of planes in the format.
To obtain optimal Android hardware buffer usage flags for specific image
creation parameters, attach an instance of
VkAndroidHardwareBufferUsageANDROID to the pNext chain of a
VkImageFormatProperties2 structure passed to
vkGetPhysicalDeviceImageFormatProperties2.
This structure is defined as:
typedef struct VkAndroidHardwareBufferUsageANDROID {
VkStructureType sType;
void* pNext;
uint64_t androidHardwareBufferUsage;
} VkAndroidHardwareBufferUsageANDROID;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
androidHardwareBufferUsagereturns the the Android hardware buffer usage flags.
The androidHardwareBufferUsage field must include Android hardware
buffer usage flags listed in the
AHardwareBuffer Usage
Equivalence table when the corresponding Vulkan image usage or image
creation flags are included in the usage or flags fields of
VkPhysicalDeviceImageFormatInfo2.
It must include at least one GPU usage flag
(AHARDWAREBUFFER_USAGE_GPU_*), even if none of the corresponding Vulkan
usages or flags are requested.
|
Note
Requiring at least one GPU usage flag ensures that Android hardware buffer memory will be allocated in a memory pool accessible to the Vulkan implementation, and that specializing the memory layout based on usage flags doesn’t prevent it from being compatible with Vulkan. Implementations may avoid unnecessary restrictions caused by this requirement by using vendor usage flags to indicate that only the Vulkan uses indicated in VkImageFormatProperties2 are required. |
32.5.1. Supported Sample Counts
vkGetPhysicalDeviceImageFormatProperties returns a bitmask of
VkSampleCountFlagBits in sampleCounts specifying the supported
sample counts for the image parameters.
sampleCounts will be set to VK_SAMPLE_COUNT_1_BIT if at least
one of the following conditions is true:
-
tilingisVK_IMAGE_TILING_LINEAR -
typeis notVK_IMAGE_TYPE_2D -
flagscontainsVK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT -
Neither the
VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BITflag nor theVK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BITflag inVkFormatProperties::optimalTilingFeaturesreturned by vkGetPhysicalDeviceFormatProperties is set -
VkPhysicalDeviceExternalImageFormatInfoKHR::handleTypeis an external handle type for which multisampled image support is not required.
Otherwise, the bits set in sampleCounts will be the sample counts
supported for the specified values of usage and format.
For each bit set in usage, the supported sample counts relate to the
limits in VkPhysicalDeviceLimits as follows:
-
If
usageincludesVK_IMAGE_USAGE_COLOR_ATTACHMENT_BITandformatis a floating- or fixed-point color format, a superset ofVkPhysicalDeviceLimits::framebufferColorSampleCounts -
If
usageincludesVK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT, andformatincludes a depth aspect, a superset ofVkPhysicalDeviceLimits::framebufferDepthSampleCounts -
If
usageincludesVK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT, andformatincludes a stencil aspect, a superset ofVkPhysicalDeviceLimits::framebufferStencilSampleCounts -
If
usageincludesVK_IMAGE_USAGE_SAMPLED_BIT, andformatincludes a color aspect, a superset ofVkPhysicalDeviceLimits::sampledImageColorSampleCounts -
If
usageincludesVK_IMAGE_USAGE_SAMPLED_BIT, andformatincludes a depth aspect, a superset ofVkPhysicalDeviceLimits::sampledImageDepthSampleCounts -
If
usageincludesVK_IMAGE_USAGE_SAMPLED_BIT, andformatis an integer format, a superset ofVkPhysicalDeviceLimits::sampledImageIntegerSampleCounts -
If
usageincludesVK_IMAGE_USAGE_STORAGE_BIT, a superset ofVkPhysicalDeviceLimits::storageImageSampleCounts
If multiple bits are set in usage, sampleCounts will be the
intersection of the per-usage values described above.
If none of the bits described above are set in usage, then there is no
corresponding limit in VkPhysicalDeviceLimits.
In this case, sampleCounts must include at least
VK_SAMPLE_COUNT_1_BIT.
32.5.2. Allowed Extent Values Based On Image Type
Implementations may support extent values larger than the required minimum/maximum values for certain types of images subject to the constraints below.
|
Note
Implementations must support images with dimensions up to the required minimum/maximum values for all types of images. It follows that the query for additional capabilities must return extent values that are at least as large as the required values. |
For VK_IMAGE_TYPE_1D:
-
maxExtent.width≥ VkPhysicalDeviceLimits.maxImageDimension1D -
maxExtent.height= 1 -
maxExtent.depth= 1
For VK_IMAGE_TYPE_2D when flags does not contain
VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT:
-
maxExtent.width≥ VkPhysicalDeviceLimits.maxImageDimension2D -
maxExtent.height≥ VkPhysicalDeviceLimits.maxImageDimension2D -
maxExtent.depth= 1
For VK_IMAGE_TYPE_2D when flags contains
VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT:
-
maxExtent.width≥ VkPhysicalDeviceLimits.maxImageDimensionCube -
maxExtent.height≥ VkPhysicalDeviceLimits.maxImageDimensionCube -
maxExtent.depth= 1
For VK_IMAGE_TYPE_3D:
-
maxExtent.width≥ VkPhysicalDeviceLimits.maxImageDimension3D -
maxExtent.height≥ VkPhysicalDeviceLimits.maxImageDimension3D -
maxExtent.depth≥ VkPhysicalDeviceLimits.maxImageDimension3D
32.6. Additional Buffer Capabilities
In addition to the capabilities described in the previous sections (Limits and Formats), implementations may support additional buffer capabilities.
To query the external handle types supported by buffers, call:
void vkGetPhysicalDeviceExternalBufferProperties(
VkPhysicalDevice physicalDevice,
const VkPhysicalDeviceExternalBufferInfo* pExternalBufferInfo,
VkExternalBufferProperties* pExternalBufferProperties);
or the equivalent command
void vkGetPhysicalDeviceExternalBufferPropertiesKHR(
VkPhysicalDevice physicalDevice,
const VkPhysicalDeviceExternalBufferInfo* pExternalBufferInfo,
VkExternalBufferProperties* pExternalBufferProperties);
-
physicalDeviceis the physical device from which to query the buffer capabilities. -
pExternalBufferInfopoints to an instance of the VkPhysicalDeviceExternalBufferInfo structure, describing the parameters that would be consumed by vkCreateBuffer. -
pExternalBufferPropertiespoints to an instance of the VkExternalBufferProperties structure in which capabilities are returned.
The VkPhysicalDeviceExternalBufferInfo structure is defined as:
typedef struct VkPhysicalDeviceExternalBufferInfo {
VkStructureType sType;
const void* pNext;
VkBufferCreateFlags flags;
VkBufferUsageFlags usage;
VkExternalMemoryHandleTypeFlagBits handleType;
} VkPhysicalDeviceExternalBufferInfo;
or the equivalent
typedef VkPhysicalDeviceExternalBufferInfo VkPhysicalDeviceExternalBufferInfoKHR;
-
sTypeis the type of this structure -
pNextis NULL or a pointer to an extension-specific structure. -
flagsis a bitmask of VkBufferCreateFlagBits describing additional parameters of the buffer, corresponding to VkBufferCreateInfo::flags. -
usageis a bitmask of VkBufferUsageFlagBits describing the intended usage of the buffer, corresponding to VkBufferCreateInfo::usage. -
handleTypeis a VkExternalMemoryHandleTypeFlagBits value specifying the memory handle type that will be used with the memory associated with the buffer.
The VkExternalBufferProperties structure is defined as:
typedef struct VkExternalBufferProperties {
VkStructureType sType;
void* pNext;
VkExternalMemoryProperties externalMemoryProperties;
} VkExternalBufferProperties;
or the equivalent
typedef VkExternalBufferProperties VkExternalBufferPropertiesKHR;
-
sTypeis the type of this structure -
pNextis NULL or a pointer to an extension-specific structure. -
externalMemoryPropertiesis an instance of the VkExternalMemoryProperties structure specifying various capabilities of the external handle type when used with the specified buffer creation parameters.
32.7. Optional Semaphore Capabilities
Semaphores may support import and export of their payload to external handles. To query the external handle types supported by semaphores, call:
void vkGetPhysicalDeviceExternalSemaphoreProperties(
VkPhysicalDevice physicalDevice,
const VkPhysicalDeviceExternalSemaphoreInfo* pExternalSemaphoreInfo,
VkExternalSemaphoreProperties* pExternalSemaphoreProperties);
or the equivalent command
void vkGetPhysicalDeviceExternalSemaphorePropertiesKHR(
VkPhysicalDevice physicalDevice,
const VkPhysicalDeviceExternalSemaphoreInfo* pExternalSemaphoreInfo,
VkExternalSemaphoreProperties* pExternalSemaphoreProperties);
-
physicalDeviceis the physical device from which to query the semaphore capabilities. -
pExternalSemaphoreInfopoints to an instance of the VkPhysicalDeviceExternalSemaphoreInfo structure, describing the parameters that would be consumed by vkCreateSemaphore. -
pExternalSemaphorePropertiespoints to an instance of the VkExternalSemaphoreProperties structure in which capabilities are returned.
The VkPhysicalDeviceExternalSemaphoreInfo structure is defined as:
typedef struct VkPhysicalDeviceExternalSemaphoreInfo {
VkStructureType sType;
const void* pNext;
VkExternalSemaphoreHandleTypeFlagBits handleType;
} VkPhysicalDeviceExternalSemaphoreInfo;
or the equivalent
typedef VkPhysicalDeviceExternalSemaphoreInfo VkPhysicalDeviceExternalSemaphoreInfoKHR;
-
sTypeis the type of this structure -
pNextis NULL or a pointer to an extension-specific structure. -
handleTypeis a VkExternalSemaphoreHandleTypeFlagBits value specifying the external semaphore handle type for which capabilities will be returned.
Bits which may be set in
VkPhysicalDeviceExternalSemaphoreInfo::handleType, specifying an
external semaphore handle type, are:
typedef enum VkExternalSemaphoreHandleTypeFlagBits {
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BIT = 0x00000001,
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT = 0x00000002,
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT = 0x00000004,
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT = 0x00000008,
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT = 0x00000010,
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BIT_KHR = VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BIT,
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT_KHR = VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT,
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT_KHR = VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT,
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT_KHR = VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT,
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT_KHR = VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT,
} VkExternalSemaphoreHandleTypeFlagBits;
or the equivalent
typedef VkExternalSemaphoreHandleTypeFlagBits VkExternalSemaphoreHandleTypeFlagBitsKHR;
-
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BITspecifies a POSIX file descriptor handle that has only limited valid usage outside of Vulkan and other compatible APIs. It must be compatible with the POSIX system callsdup,dup2,close, and the non-standard system calldup3. Additionally, it must be transportable over a socket using anSCM_RIGHTScontrol message. It owns a reference to the underlying synchronization primitive represented by its Vulkan semaphore object. -
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BITspecifies an NT handle that has only limited valid usage outside of Vulkan and other compatible APIs. It must be compatible with the functionsDuplicateHandle,CloseHandle,CompareObjectHandles,GetHandleInformation, andSetHandleInformation. It owns a reference to the underlying synchronization primitive represented by its Vulkan semaphore object. -
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BITspecifies a global share handle that has only limited valid usage outside of Vulkan and other compatible APIs. It is not compatible with any native APIs. It does not own a reference to the underlying synchronization primitive represented its Vulkan semaphore object, and will therefore become invalid when all Vulkan semaphore objects associated with it are destroyed. -
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BITspecifies an NT handle returned byID3D12Device::CreateSharedHandlereferring to a Direct3D 12 fence. It owns a reference to the underlying synchronization primitive associated with the Direct3D fence. -
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BITspecifies a POSIX file descriptor handle to a Linux Sync File or Android Fence object. It can be used with any native API accepting a valid sync file or fence as input. It owns a reference to the underlying synchronization primitive associated with the file descriptor. Implementations which support importing this handle type must accept any type of sync or fence FD supported by the native system they are running on.
|
Note
Handles of type |
Some external semaphore handle types can only be shared within the same underlying physical device and/or the same driver version, as defined in the following table:
Handle type |
|
|
|
Must match |
Must match |
|
Must match |
Must match |
|
Must match |
Must match |
|
Must match |
Must match |
|
No restriction |
No restriction |
typedef VkFlags VkExternalSemaphoreHandleTypeFlags;
or the equivalent
typedef VkExternalSemaphoreHandleTypeFlags VkExternalSemaphoreHandleTypeFlagsKHR;
VkExternalSemaphoreHandleTypeFlags is a bitmask type for setting a
mask of zero or more VkExternalSemaphoreHandleTypeFlagBits.
The VkExternalSemaphoreProperties structure is defined as:
typedef struct VkExternalSemaphoreProperties {
VkStructureType sType;
void* pNext;
VkExternalSemaphoreHandleTypeFlags exportFromImportedHandleTypes;
VkExternalSemaphoreHandleTypeFlags compatibleHandleTypes;
VkExternalSemaphoreFeatureFlags externalSemaphoreFeatures;
} VkExternalSemaphoreProperties;
or the equivalent
typedef VkExternalSemaphoreProperties VkExternalSemaphorePropertiesKHR;
-
exportFromImportedHandleTypesis a bitmask of VkExternalSemaphoreHandleTypeFlagBits specifying which types of imported handlehandleTypecan be exported from. -
compatibleHandleTypesis a bitmask of VkExternalSemaphoreHandleTypeFlagBits specifying handle types which can be specified at the same time ashandleTypewhen creating a semaphore. -
externalSemaphoreFeaturesis a bitmask of VkExternalSemaphoreFeatureFlagBits describing the features ofhandleType.
If handleType is not supported by the implementation, then
VkExternalSemaphoreProperties::externalSemaphoreFeatures will be
set to zero.
Possible values of
VkExternalSemaphoreProperties::externalSemaphoreFeatures,
specifying the features of an external semaphore handle type, are:
typedef enum VkExternalSemaphoreFeatureFlagBits {
VK_EXTERNAL_SEMAPHORE_FEATURE_EXPORTABLE_BIT = 0x00000001,
VK_EXTERNAL_SEMAPHORE_FEATURE_IMPORTABLE_BIT = 0x00000002,
VK_EXTERNAL_SEMAPHORE_FEATURE_EXPORTABLE_BIT_KHR = VK_EXTERNAL_SEMAPHORE_FEATURE_EXPORTABLE_BIT,
VK_EXTERNAL_SEMAPHORE_FEATURE_IMPORTABLE_BIT_KHR = VK_EXTERNAL_SEMAPHORE_FEATURE_IMPORTABLE_BIT,
} VkExternalSemaphoreFeatureFlagBits;
or the equivalent
typedef VkExternalSemaphoreFeatureFlagBits VkExternalSemaphoreFeatureFlagBitsKHR;
-
VK_EXTERNAL_SEMAPHORE_FEATURE_EXPORTABLE_BITspecifies that handles of this type can be exported from Vulkan semaphore objects. -
VK_EXTERNAL_SEMAPHORE_FEATURE_IMPORTABLE_BITspecifies that handles of this type can be imported as Vulkan semaphore objects.
typedef VkFlags VkExternalSemaphoreFeatureFlags;
or the equivalent
typedef VkExternalSemaphoreFeatureFlags VkExternalSemaphoreFeatureFlagsKHR;
VkExternalSemaphoreFeatureFlags is a bitmask type for setting a mask
of zero or more VkExternalSemaphoreFeatureFlagBits.
32.8. Optional Fence Capabilities
Fences may support import and export of their payload to external handles. To query the external handle types supported by fences, call:
void vkGetPhysicalDeviceExternalFenceProperties(
VkPhysicalDevice physicalDevice,
const VkPhysicalDeviceExternalFenceInfo* pExternalFenceInfo,
VkExternalFenceProperties* pExternalFenceProperties);
or the equivalent command
void vkGetPhysicalDeviceExternalFencePropertiesKHR(
VkPhysicalDevice physicalDevice,
const VkPhysicalDeviceExternalFenceInfo* pExternalFenceInfo,
VkExternalFenceProperties* pExternalFenceProperties);
-
physicalDeviceis the physical device from which to query the fence capabilities. -
pExternalFenceInfopoints to an instance of the VkPhysicalDeviceExternalFenceInfo structure, describing the parameters that would be consumed by vkCreateFence. -
pExternalFencePropertiespoints to an instance of the VkExternalFenceProperties structure in which capabilities are returned.
The VkPhysicalDeviceExternalFenceInfo structure is defined as:
typedef struct VkPhysicalDeviceExternalFenceInfo {
VkStructureType sType;
const void* pNext;
VkExternalFenceHandleTypeFlagBits handleType;
} VkPhysicalDeviceExternalFenceInfo;
or the equivalent
typedef VkPhysicalDeviceExternalFenceInfo VkPhysicalDeviceExternalFenceInfoKHR;
-
sTypeis the type of this structure -
pNextis NULL or a pointer to an extension-specific structure. -
handleTypeis a VkExternalFenceHandleTypeFlagBits value indicating an external fence handle type for which capabilities will be returned.
|
Note
Handles of type |
Bits which may be set in
VkPhysicalDeviceExternalFenceInfo::handleType, and in the
exportFromImportedHandleTypes and compatibleHandleTypes members
of VkExternalFenceProperties, to indicate external fence handle types,
are:
typedef enum VkExternalFenceHandleTypeFlagBits {
VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_FD_BIT = 0x00000001,
VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BIT = 0x00000002,
VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT = 0x00000004,
VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT = 0x00000008,
VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_FD_BIT_KHR = VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_FD_BIT,
VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BIT_KHR = VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BIT,
VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT_KHR = VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT,
VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT_KHR = VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT,
} VkExternalFenceHandleTypeFlagBits;
or the equivalent
typedef VkExternalFenceHandleTypeFlagBits VkExternalFenceHandleTypeFlagBitsKHR;
-
VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_FD_BITspecifies a POSIX file descriptor handle that has only limited valid usage outside of Vulkan and other compatible APIs. It must be compatible with the POSIX system callsdup,dup2,close, and the non-standard system calldup3. Additionally, it must be transportable over a socket using anSCM_RIGHTScontrol message. It owns a reference to the underlying synchronization primitive represented by its Vulkan fence object. -
VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BITspecifies an NT handle that has only limited valid usage outside of Vulkan and other compatible APIs. It must be compatible with the functionsDuplicateHandle,CloseHandle,CompareObjectHandles,GetHandleInformation, andSetHandleInformation. It owns a reference to the underlying synchronization primitive represented by its Vulkan fence object. -
VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BITspecifies a global share handle that has only limited valid usage outside of Vulkan and other compatible APIs. It is not compatible with any native APIs. It does not own a reference to the underlying synchronization primitive represented by its Vulkan fence object, and will therefore become invalid when all Vulkan fence objects associated with it are destroyed. -
VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BITspecifies a POSIX file descriptor handle to a Linux Sync File or Android Fence. It can be used with any native API accepting a valid sync file or fence as input. It owns a reference to the underlying synchronization primitive associated with the file descriptor. Implementations which support importing this handle type must accept any type of sync or fence FD supported by the native system they are running on.
Some external fence handle types can only be shared within the same underlying physical device and/or the same driver version, as defined in the following table:
Handle type |
|
|
|
Must match |
Must match |
|
Must match |
Must match |
|
Must match |
Must match |
|
No restriction |
No restriction |
typedef VkFlags VkExternalFenceHandleTypeFlags;
or the equivalent
typedef VkExternalFenceHandleTypeFlags VkExternalFenceHandleTypeFlagsKHR;
VkExternalFenceHandleTypeFlags is a bitmask type for setting a mask of
zero or more VkExternalFenceHandleTypeFlagBits.
The VkExternalFenceProperties structure is defined as:
typedef struct VkExternalFenceProperties {
VkStructureType sType;
void* pNext;
VkExternalFenceHandleTypeFlags exportFromImportedHandleTypes;
VkExternalFenceHandleTypeFlags compatibleHandleTypes;
VkExternalFenceFeatureFlags externalFenceFeatures;
} VkExternalFenceProperties;
or the equivalent
typedef VkExternalFenceProperties VkExternalFencePropertiesKHR;
-
exportFromImportedHandleTypesis a bitmask of VkExternalFenceHandleTypeFlagBits indicating which types of imported handlehandleTypecan be exported from. -
compatibleHandleTypesis a bitmask of VkExternalFenceHandleTypeFlagBits specifying handle types which can be specified at the same time ashandleTypewhen creating a fence. -
externalFenceFeaturesis a bitmask of VkExternalFenceFeatureFlagBits indicating the features ofhandleType.
If handleType is not supported by the implementation, then
VkExternalFenceProperties::externalFenceFeatures will be set to
zero.
Bits which may be set in
VkExternalFenceProperties::externalFenceFeatures, indicating
features of a fence external handle type, are:
typedef enum VkExternalFenceFeatureFlagBits {
VK_EXTERNAL_FENCE_FEATURE_EXPORTABLE_BIT = 0x00000001,
VK_EXTERNAL_FENCE_FEATURE_IMPORTABLE_BIT = 0x00000002,
VK_EXTERNAL_FENCE_FEATURE_EXPORTABLE_BIT_KHR = VK_EXTERNAL_FENCE_FEATURE_EXPORTABLE_BIT,
VK_EXTERNAL_FENCE_FEATURE_IMPORTABLE_BIT_KHR = VK_EXTERNAL_FENCE_FEATURE_IMPORTABLE_BIT,
} VkExternalFenceFeatureFlagBits;
or the equivalent
typedef VkExternalFenceFeatureFlagBits VkExternalFenceFeatureFlagBitsKHR;
-
VK_EXTERNAL_FENCE_FEATURE_EXPORTABLE_BITspecifies handles of this type can be exported from Vulkan fence objects. -
VK_EXTERNAL_FENCE_FEATURE_IMPORTABLE_BITspecifies handles of this type can be imported to Vulkan fence objects.
typedef VkFlags VkExternalFenceFeatureFlags;
or the equivalent
typedef VkExternalFenceFeatureFlags VkExternalFenceFeatureFlagsKHR;
VkExternalFenceFeatureFlags is a bitmask type for setting a mask of
zero or more VkExternalFenceFeatureFlagBits.
33. Debugging
To aid developers in tracking down errors in the application’s use of Vulkan, particularly in combination with an external debugger or profiler, debugging extensions may be available.
The VkObjectType enumeration defines values, each of which corresponds to a specific Vulkan handle type. These values can be used to associate debug information with a particular type of object through one or more extensions.
typedef enum VkObjectType {
VK_OBJECT_TYPE_UNKNOWN = 0,
VK_OBJECT_TYPE_INSTANCE = 1,
VK_OBJECT_TYPE_PHYSICAL_DEVICE = 2,
VK_OBJECT_TYPE_DEVICE = 3,
VK_OBJECT_TYPE_QUEUE = 4,
VK_OBJECT_TYPE_SEMAPHORE = 5,
VK_OBJECT_TYPE_COMMAND_BUFFER = 6,
VK_OBJECT_TYPE_FENCE = 7,
VK_OBJECT_TYPE_DEVICE_MEMORY = 8,
VK_OBJECT_TYPE_BUFFER = 9,
VK_OBJECT_TYPE_IMAGE = 10,
VK_OBJECT_TYPE_EVENT = 11,
VK_OBJECT_TYPE_QUERY_POOL = 12,
VK_OBJECT_TYPE_BUFFER_VIEW = 13,
VK_OBJECT_TYPE_IMAGE_VIEW = 14,
VK_OBJECT_TYPE_SHADER_MODULE = 15,
VK_OBJECT_TYPE_PIPELINE_CACHE = 16,
VK_OBJECT_TYPE_PIPELINE_LAYOUT = 17,
VK_OBJECT_TYPE_RENDER_PASS = 18,
VK_OBJECT_TYPE_PIPELINE = 19,
VK_OBJECT_TYPE_DESCRIPTOR_SET_LAYOUT = 20,
VK_OBJECT_TYPE_SAMPLER = 21,
VK_OBJECT_TYPE_DESCRIPTOR_POOL = 22,
VK_OBJECT_TYPE_DESCRIPTOR_SET = 23,
VK_OBJECT_TYPE_FRAMEBUFFER = 24,
VK_OBJECT_TYPE_COMMAND_POOL = 25,
VK_OBJECT_TYPE_SAMPLER_YCBCR_CONVERSION = 1000156000,
VK_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE = 1000085000,
VK_OBJECT_TYPE_SURFACE_KHR = 1000000000,
VK_OBJECT_TYPE_SWAPCHAIN_KHR = 1000001000,
VK_OBJECT_TYPE_DISPLAY_KHR = 1000002000,
VK_OBJECT_TYPE_DISPLAY_MODE_KHR = 1000002001,
VK_OBJECT_TYPE_DEBUG_REPORT_CALLBACK_EXT = 1000011000,
VK_OBJECT_TYPE_OBJECT_TABLE_NVX = 1000086000,
VK_OBJECT_TYPE_INDIRECT_COMMANDS_LAYOUT_NVX = 1000086001,
VK_OBJECT_TYPE_DEBUG_UTILS_MESSENGER_EXT = 1000128000,
VK_OBJECT_TYPE_VALIDATION_CACHE_EXT = 1000160000,
VK_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_KHR = VK_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE,
VK_OBJECT_TYPE_SAMPLER_YCBCR_CONVERSION_KHR = VK_OBJECT_TYPE_SAMPLER_YCBCR_CONVERSION,
} VkObjectType;
| VkObjectType | Vulkan Handle Type |
|---|---|
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If this Specification was generated with any such extensions included, they will be described in the remainder of this chapter.
33.1. Debug Utilities
Vulkan provides flexible debugging utilities for debugging an application.
The Object Debug Annotation section describes how to associate either a name or binary data with a specific Vulkan object.
The Queue Labels section describes how to annotate and group the work submitted to a queue.
The Command Buffer Labels section describes how to associate logical elements of the scene with commands in a VkCommandBuffer.
The Debug Messengers section describes how to create debug messenger objects associated with an application supplied callback to capture debug messages from a variety of Vulkan components.
33.1.1. Object Debug Annotation
It can be useful for an application to provide its own content relative to a specific Vulkan object. The following commands allow application developers to associate user-defined information with Vulkan objects.
Object Naming
An object can be provided a user-defined name by calling
vkSetDebugUtilsObjectNameEXT as defined below.
VkResult vkSetDebugUtilsObjectNameEXT(
VkDevice device,
const VkDebugUtilsObjectNameInfoEXT* pNameInfo);
-
deviceis the device that created the object. -
pNameInfois a pointer to an instance of the VkDebugUtilsObjectNameInfoEXT structure specifying the parameters of the name to set on the object.
The VkDebugUtilsObjectNameInfoEXT structure is defined as:
typedef struct VkDebugUtilsObjectNameInfoEXT {
VkStructureType sType;
const void* pNext;
VkObjectType objectType;
uint64_t objectHandle;
const char* pObjectName;
} VkDebugUtilsObjectNameInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
objectTypeis a VkObjectType specifying the type of the object to be named. -
objectHandleis the object to be named. -
pObjectNameis a null-terminated UTF-8 string specifying the name to apply toobjectHandle.
Applications may change the name associated with an object simply by
calling vkSetDebugUtilsObjectNameEXT again with a new string.
If pObjectName is an empty string, then any previously set name is
removed.
Object Data Association
In addition to setting a name for an object, debugging and validation layers may have uses for additional binary data on a per-object basis that have no other place in the Vulkan API.
For example, a VkShaderModule could have additional debugging data
attached to it to aid in offline shader tracing.
Additional data can be attached to an object by calling
vkSetDebugUtilsObjectTagEXT as defined below.
VkResult vkSetDebugUtilsObjectTagEXT(
VkDevice device,
const VkDebugUtilsObjectTagInfoEXT* pTagInfo);
-
deviceis the device that created the object. -
pTagInfois a pointer to an instance of the VkDebugUtilsObjectTagInfoEXT structure specifying the parameters of the tag to attach to the object.
The VkDebugUtilsObjectTagInfoEXT structure is defined as:
typedef struct VkDebugUtilsObjectTagInfoEXT {
VkStructureType sType;
const void* pNext;
VkObjectType objectType;
uint64_t objectHandle;
uint64_t tagName;
size_t tagSize;
const void* pTag;
} VkDebugUtilsObjectTagInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
objectTypeis a VkObjectType specifying the type of the object to be named. -
objectHandleis the object to be tagged. -
tagNameis a numerical identifier of the tag. -
tagSizeis the number of bytes of data to attach to the object. -
pTagis an array oftagSizebytes containing the data to be associated with the object.
The tagName parameter gives a name or identifier to the type of data
being tagged.
This can be used by debugging layers to easily filter for only data that can
be used by that implementation.
33.1.2. Queue Labels
All Vulkan work must be submitted using queues. It is possible for an application to use multiple queues, each containing multiple command buffers, when performing work. It can be useful to identify which queue, or even where in a queue, something has occurred.
To begin identifying a region using a debug label inside a queue, you may use the vkQueueBeginDebugUtilsLabelEXT command.
Then, when the region of interest has passed, you may end the label region using vkQueueEndDebugUtilsLabelEXT.
Additionally, a single debug label may be inserted at any time using vkQueueInsertDebugUtilsLabelEXT.
A queue debug label region is opened by calling:
void vkQueueBeginDebugUtilsLabelEXT(
VkQueue queue,
const VkDebugUtilsLabelEXT* pLabelInfo);
-
queueis the queue in which to start a debug label region. -
pLabelInfois a pointer to an instance of the VkDebugUtilsLabelEXT structure specifying the parameters of the label region to open.
The VkDebugUtilsLabelEXT structure is defined as:
typedef struct VkDebugUtilsLabelEXT {
VkStructureType sType;
const void* pNext;
const char* pLabelName;
float color[4];
} VkDebugUtilsLabelEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
pLabelNameis a pointer to a null-terminated UTF-8 string that contains the name of the label. -
coloris an optional RGBA color value that can be associated with the label. A particular implementation may choose to ignore this color value. The values contain RGBA values in order, in the range 0.0 to 1.0. If all elements incolorare set to 0.0 then it is ignored.
A queue debug label region is closed by calling:
void vkQueueEndDebugUtilsLabelEXT(
VkQueue queue);
-
queueis the queue in which a debug label region should be closed.
The calls to vkQueueBeginDebugUtilsLabelEXT and vkQueueEndDebugUtilsLabelEXT must be matched and balanced.
A single label can be inserted into a queue by calling:
void vkQueueInsertDebugUtilsLabelEXT(
VkQueue queue,
const VkDebugUtilsLabelEXT* pLabelInfo);
-
queueis the queue into which a debug label will be inserted. -
pLabelInfois a pointer to an instance of the VkDebugUtilsLabelEXT structure specifying the parameters of the label to insert.
33.1.3. Command Buffer Labels
Typical Vulkan applications will submit many command buffers in each frame, with each command buffer containing a large number of individual commands. Being able to logically annotate regions of command buffers that belong together as well as hierarchically subdivide the frame is important to a developer’s ability to navigate the commands viewed holistically.
To identify the beginning of a debug label region in a command buffer, vkCmdBeginDebugUtilsLabelEXT can be used as defined below.
To indicate the end of a debug label region in a command buffer, vkCmdEndDebugUtilsLabelEXT can be used.
To insert a single command buffer debug label inside of a command buffer, vkCmdInsertDebugUtilsLabelEXT can be used as defined below.
A command buffer debug label region can be opened by calling:
void vkCmdBeginDebugUtilsLabelEXT(
VkCommandBuffer commandBuffer,
const VkDebugUtilsLabelEXT* pLabelInfo);
-
commandBufferis the command buffer into which the command is recorded. -
pLabelInfois a pointer to an instance of the VkDebugUtilsLabelEXT structure specifying the parameters of the label region to open.
A command buffer label region can be closed by calling:
void vkCmdEndDebugUtilsLabelEXT(
VkCommandBuffer commandBuffer);
-
commandBufferis the command buffer into which the command is recorded.
An application may open a debug label region in one command buffer and close it in another, or otherwise split debug label regions across multiple command buffers or multiple queue submissions. When viewed from the linear series of submissions to a single queue, the calls to vkCmdBeginDebugUtilsLabelEXT and vkCmdEndDebugUtilsLabelEXT must be matched and balanced.
A single debug label can be inserted into a command buffer by calling:
void vkCmdInsertDebugUtilsLabelEXT(
VkCommandBuffer commandBuffer,
const VkDebugUtilsLabelEXT* pLabelInfo);
-
commandBufferis the command buffer into which the command is recorded. -
pInfois a pointer to an instance of the VkDebugUtilsLabelEXT structure specifying the parameters of the label to insert.
33.1.4. Debug Messengers
Vulkan allows an application to register multiple callbacks with any Vulkan component wishing to report debug information. Some callbacks may log the information to a file, others may cause a debug break point or other application defined behavior. A primary producer of callback messages are the validation layers. An application can register callbacks even when no validation layers are enabled, but they will only be called for the Vulkan loader and, if implemented, other layer and driver events.
A VkDebugUtilsMessengerEXT is a messenger object which handles passing
along debug messages to a provided debug callback.
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDebugUtilsMessengerEXT)
The debug messenger will provide detailed feedback on the application’s use of Vulkan when events of interest occur. When an event of interest does occur, the debug messenger will submit a debug message to the debug callback that was provided during its creation. Additionally, the debug messenger is responsible with filtering out debug messages that the callback isn’t interested in and will only provide desired debug messages.
A debug messenger triggers a debug callback with a debug message when an event of interest occurs. To create a debug messenger which will trigger a debug callback, call:
VkResult vkCreateDebugUtilsMessengerEXT(
VkInstance instance,
const VkDebugUtilsMessengerCreateInfoEXT* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkDebugUtilsMessengerEXT* pMessenger);
-
instancethe instance the messenger will be used with. -
pCreateInfopoints to a VkDebugUtilsMessengerCreateInfoEXT structure which contains the callback pointer as well as defines the conditions under which this messenger will trigger the callback. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pMessengeris a pointer to record theVkDebugUtilsMessengerEXTobject created.
The definition of VkDebugUtilsMessengerCreateInfoEXT is:
typedef struct VkDebugUtilsMessengerCreateInfoEXT {
VkStructureType sType;
const void* pNext;
VkDebugUtilsMessengerCreateFlagsEXT flags;
VkDebugUtilsMessageSeverityFlagsEXT messageSeverity;
VkDebugUtilsMessageTypeFlagsEXT messageType;
PFN_vkDebugUtilsMessengerCallbackEXT pfnUserCallback;
void* pUserData;
} VkDebugUtilsMessengerCreateInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis 0 and reserved for future use. -
messageSeverityis a bitmask of VkDebugUtilsMessageSeverityFlagBitsEXT specifying which severity of event(s) will cause this callback to be called. -
messageTypesis a bitmask of VkDebugUtilsMessageTypeFlagBitsEXT specifying which type of event(s) will cause this callback to be called. -
pfnUserCallbackis the application callback function to call. -
pUserDatais user data to be passed to the callback.
For each VkDebugUtilsMessengerEXT that is created the
VkDebugUtilsMessengerCreateInfoEXT::messageSeverity and
VkDebugUtilsMessengerCreateInfoEXT::messageTypes determine when
that VkDebugUtilsMessengerCreateInfoEXT::pfnUserCallback is
called.
The process to determine if the user’s pfnUserCallback is triggered when an
event occurs is as follows:
-
The implementation will perform a bitwise AND of the event’s VkDebugUtilsMessageSeverityFlagBitsEXT with the
messageSeverityprovided during creation of the VkDebugUtilsMessengerEXT object.-
If the value is 0, the message is skipped.
-
-
The implementation will perform bitwise AND of the event’s VkDebugUtilsMessageTypeFlagBitsEXT with the
messageTypeprovided during the creation of the VkDebugUtilsMessengerEXT object.-
If the value is 0, the message is skipped.
-
-
The callback will trigger a debug message for the current event
The callback will come directly from the component that detected the event, unless some other layer intercepts the calls for its own purposes (filter them in a different way, log to a system error log, etc.).
An application can receive multiple callbacks if multiple
VkDebugUtilsMessengerEXT objects are created.
A callback will always be executed in the same thread as the originating
Vulkan call.
A callback can be called from multiple threads simultaneously (if the application is making Vulkan calls from multiple threads).
Bits which can be set in
VkDebugUtilsMessengerCreateInfoEXT::messageSeverity, specifying
event severities which cause a debug messenger to call the callback, are:
typedef enum VkDebugUtilsMessageSeverityFlagBitsEXT {
VK_DEBUG_UTILS_MESSAGE_SEVERITY_VERBOSE_BIT_EXT = 0x00000001,
VK_DEBUG_UTILS_MESSAGE_SEVERITY_INFO_BIT_EXT = 0x00000010,
VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT = 0x00000100,
VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT = 0x00001000,
} VkDebugUtilsMessageSeverityFlagBitsEXT;
-
VK_DEBUG_UTILS_MESSAGE_SEVERITY_VERBOSE_BIT_EXTspecifies the most verbose output indicating all diagnostic messages from the Vulkan loader, layers, and drivers should be captured. -
VK_DEBUG_UTILS_MESSAGE_SEVERITY_INFO_BIT_EXTspecifies an informational message such as resource details that may be handy when debugging an application. -
VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXTspecifies use of Vulkan that may expose an app bug. Such cases may not be immediately harmful, such as a fragment shader outputting to a location with no attachment. Other cases may point to behavior that is almost certainly bad when unintended such as using an image whose memory has not been filled. In general if you see a warning but you know that the behavior is intended/desired, then simply ignore the warning. -
VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXTspecifies that an error that may cause undefined results, including an application crash.
|
Note
The values of For example:
In addition, space has been left between the enums to allow for later addition of new severities in between the existing values. |
Bits which can be set in
VkDebugUtilsMessengerCreateInfoEXT::messageTypes, specifying
event types which cause a debug messenger to call the callback, are:
typedef enum VkDebugUtilsMessageTypeFlagBitsEXT {
VK_DEBUG_UTILS_MESSAGE_TYPE_GENERAL_BIT_EXT = 0x00000001,
VK_DEBUG_UTILS_MESSAGE_TYPE_VALIDATION_BIT_EXT = 0x00000002,
VK_DEBUG_UTILS_MESSAGE_TYPE_PERFORMANCE_BIT_EXT = 0x00000004,
} VkDebugUtilsMessageTypeFlagBitsEXT;
-
VK_DEBUG_UTILS_MESSAGE_TYPE_GENERAL_BIT_EXTspecifies that some general event has occurred. This is typically a non-specification, non-performance event. -
VK_DEBUG_UTILS_MESSAGE_TYPE_VALIDATION_BIT_EXTspecifies that something has occurred during validation against the Vulkan specification that may indicate invalid behavior. -
VK_DEBUG_UTILS_MESSAGE_TYPE_PERFORMANCE_BIT_EXTspecifies a potentially non-optimal use of Vulkan, e.g. using vkCmdClearColorImage when setting VkAttachmentDescription::loadOptoVK_ATTACHMENT_LOAD_OP_CLEARwould have worked.
The prototype for the
VkDebugUtilsMessengerCreateInfoEXT::pfnUserCallback function
implemented by the application is:
typedef VkBool32 (VKAPI_PTR *PFN_vkDebugUtilsMessengerCallbackEXT)(
VkDebugUtilsMessageSeverityFlagBitsEXT messageSeverity,
VkDebugUtilsMessageTypeFlagsEXT messageType,
const VkDebugUtilsMessengerCallbackDataEXT* pCallbackData,
void* pUserData);
-
messageSeverityspecifies the VkDebugUtilsMessageSeverityFlagBitsEXT that triggered this callback. -
messageTypesspecifies the VkDebugUtilsMessageTypeFlagBitsEXT that triggered this callback. -
pCallbackDatacontains all the callback related data in the VkDebugUtilsMessengerCallbackDataEXT structure. -
pUserDatais the user data provided when the VkDebugUtilsMessengerEXT was created.
The callback must not call vkDestroyDebugUtilsMessengerEXT.
The callback returns a VkBool32, which is interpreted in a
layer-specified manner.
The application should always return VK_FALSE.
The VK_TRUE value is reserved for use in layer development.
The definition of VkDebugUtilsMessengerCallbackDataEXT is:
typedef struct VkDebugUtilsMessengerCallbackDataEXT {
VkStructureType sType;
const void* pNext;
VkDebugUtilsMessengerCallbackDataFlagsEXT flags;
const char* pMessageIdName;
int32_t messageIdNumber;
const char* pMessage;
uint32_t queueLabelCount;
VkDebugUtilsLabelEXT* pQueueLabels;
uint32_t cmdBufLabelCount;
VkDebugUtilsLabelEXT* pCmdBufLabels;
uint32_t objectCount;
VkDebugUtilsObjectNameInfoEXT* pObjects;
} VkDebugUtilsMessengerCallbackDataEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis 0 and reserved for future use. -
pMessageIdNameis a null-terminated string that identifies the the particular message ID that is associated with the provided message. If the message corresponds to a validation layer message, then this string may contain the portion of the Vulkan specification that is believed to have been violated. -
messageIdNumberis the ID number of the triggering message. If the message corresponds to a validation layer message, then this number is related to the internal number associated with the message being triggered. -
pMessageis a null-terminated string detailing the trigger conditions. -
queueLabelCountis a count of items contained in thepQueueLabelsarray. -
pQueueLabelsis NULL or a pointer to an array of VkDebugUtilsLabelEXT active in the currentVkQueueat the time the callback was triggered. Refer to Queue Labels for more information. -
cmdBufLabelCountis a count of items contained in thepCmdBufLabelsarray. -
pCmdBufLabelsis NULL or a pointer to an array of VkDebugUtilsLabelEXT active in the currentVkCommandBufferat the time the callback was triggered. Refer to Command Buffer Labels for more information. -
objectCountis a count of items contained in thepObjectsarray. -
pObjectsis a pointer to an array of VkDebugUtilsObjectNameInfoEXT objects related to the detected issue. The array is roughly in order or importance, but the 0th element is always guaranteed to be the most important object for this message.
|
Note
This structure should only be considered valid during the lifetime of the triggered callback. |
Since adding queue and command buffer labels behaves like pushing and
popping onto a stack, the order of both pQueueLabels and
pCmdBufLabels is based on the order the labels were defined.
The result is that the first label in either pQueueLabels or
pCmdBufLabels will be the first defined (and therefore the oldest)
while the last label in each list will be the most recent.
|
Note
Likewise, |
There may be times that a user wishes to intentionally submit a debug message. To do this, call:
void vkSubmitDebugUtilsMessageEXT(
VkInstance instance,
VkDebugUtilsMessageSeverityFlagBitsEXT messageSeverity,
VkDebugUtilsMessageTypeFlagsEXT messageTypes,
const VkDebugUtilsMessengerCallbackDataEXT* pCallbackData);
-
instanceis the debug stream’sVkInstance. -
messageSeverityis the VkDebugUtilsMessageSeverityFlagBitsEXT severity of this event/message. -
messageTypesis a bitmask of VkDebugUtilsMessageTypeFlagBitsEXT specifying which type of event(s) to identify with this message. -
pCallbackDatacontains all the callback related data in the VkDebugUtilsMessengerCallbackDataEXT structure.
The call will propagate through the layers and generate callback(s) as
indicated by the message’s flags.
The parameters are passed on to the callback in addition to the
pUserData value that was defined at the time the messenger was
registered.
To destroy a VkDebugUtilsMessengerEXT object, call:
void vkDestroyDebugUtilsMessengerEXT(
VkInstance instance,
VkDebugUtilsMessengerEXT messenger,
const VkAllocationCallbacks* pAllocator);
-
instancethe instance where the callback was created. -
messengertheVkDebugUtilsMessengerEXTobject to destroy.messengeris an externally synchronized object and must not be used on more than one thread at a time. This means thatvkDestroyDebugUtilsMessengerEXTmust not be called when a callback is active. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
33.2. Debug Markers
Debug markers provide a flexible way for debugging and validation layers to receive annotation and debug information.
The Object Annotation section describes how to associate a name or binary data with a Vulkan object.
The Command Buffer Markers section describes how to associate logical elements of the scene with commands in the command buffer.
33.2.1. Object Annotation
The commands in this section allow application developers to associate user-defined information with Vulkan objects at will.
An object can be given a user-friendly name by calling:
VkResult vkDebugMarkerSetObjectNameEXT(
VkDevice device,
const VkDebugMarkerObjectNameInfoEXT* pNameInfo);
-
deviceis the device that created the object. -
pNameInfois a pointer to an instance of the VkDebugMarkerObjectNameInfoEXT structure specifying the parameters of the name to set on the object.
The VkDebugMarkerObjectNameInfoEXT structure is defined as:
typedef struct VkDebugMarkerObjectNameInfoEXT {
VkStructureType sType;
const void* pNext;
VkDebugReportObjectTypeEXT objectType;
uint64_t object;
const char* pObjectName;
} VkDebugMarkerObjectNameInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
objectTypeis a VkDebugReportObjectTypeEXT specifying the type of the object to be named. -
objectis the object to be named. -
pObjectNameis a null-terminated UTF-8 string specifying the name to apply toobject.
Applications may change the name associated with an object simply by
calling vkDebugMarkerSetObjectNameEXT again with a new string.
To remove a previously set name, pObjectName should be set to an
empty string.
In addition to setting a name for an object, debugging and validation layers
may have uses for additional binary data on a per-object basis that has no
other place in the Vulkan API.
For example, a VkShaderModule could have additional debugging data
attached to it to aid in offline shader tracing.
To attach data to an object, call:
VkResult vkDebugMarkerSetObjectTagEXT(
VkDevice device,
const VkDebugMarkerObjectTagInfoEXT* pTagInfo);
-
deviceis the device that created the object. -
pTagInfois a pointer to an instance of the VkDebugMarkerObjectTagInfoEXT structure specifying the parameters of the tag to attach to the object.
The VkDebugMarkerObjectTagInfoEXT structure is defined as:
typedef struct VkDebugMarkerObjectTagInfoEXT {
VkStructureType sType;
const void* pNext;
VkDebugReportObjectTypeEXT objectType;
uint64_t object;
uint64_t tagName;
size_t tagSize;
const void* pTag;
} VkDebugMarkerObjectTagInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
objectTypeis a VkDebugReportObjectTypeEXT specifying the type of the object to be named. -
objectis the object to be tagged. -
tagNameis a numerical identifier of the tag. -
tagSizeis the number of bytes of data to attach to the object. -
pTagis an array oftagSizebytes containing the data to be associated with the object.
The tagName parameter gives a name or identifier to the type of data
being tagged.
This can be used by debugging layers to easily filter for only data that can
be used by that implementation.
33.2.2. Command Buffer Markers
Typical Vulkan applications will submit many command buffers in each frame, with each command buffer containing a large number of individual commands. Being able to logically annotate regions of command buffers that belong together as well as hierarchically subdivide the frame is important to a developer’s ability to navigate the commands viewed holistically.
The marker commands vkCmdDebugMarkerBeginEXT and
vkCmdDebugMarkerEndEXT define regions of a series of commands that are
grouped together, and they can be nested to create a hierarchy.
The vkCmdDebugMarkerInsertEXT command allows insertion of a single
label within a command buffer.
A marker region can be opened by calling:
void vkCmdDebugMarkerBeginEXT(
VkCommandBuffer commandBuffer,
const VkDebugMarkerMarkerInfoEXT* pMarkerInfo);
-
commandBufferis the command buffer into which the command is recorded. -
pMarkerInfois a pointer to an instance of the VkDebugMarkerMarkerInfoEXT structure specifying the parameters of the marker region to open.
The VkDebugMarkerMarkerInfoEXT structure is defined as:
typedef struct VkDebugMarkerMarkerInfoEXT {
VkStructureType sType;
const void* pNext;
const char* pMarkerName;
float color[4];
} VkDebugMarkerMarkerInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
pMarkerNameis a pointer to a null-terminated UTF-8 string that contains the name of the marker. -
coloris an optional RGBA color value that can be associated with the marker. A particular implementation may choose to ignore this color value. The values contain RGBA values in order, in the range 0.0 to 1.0. If all elements incolorare set to 0.0 then it is ignored.
A marker region can be closed by calling:
void vkCmdDebugMarkerEndEXT(
VkCommandBuffer commandBuffer);
-
commandBufferis the command buffer into which the command is recorded.
An application may open a marker region in one command buffer and close it
in another, or otherwise split marker regions across multiple command
buffers or multiple queue submissions.
When viewed from the linear series of submissions to a single queue, the
calls to vkCmdDebugMarkerBeginEXT and vkCmdDebugMarkerEndEXT
must be matched and balanced.
A single marker label can be inserted into a command buffer by calling:
void vkCmdDebugMarkerInsertEXT(
VkCommandBuffer commandBuffer,
const VkDebugMarkerMarkerInfoEXT* pMarkerInfo);
-
commandBufferis the command buffer into which the command is recorded. -
pMarkerInfois a pointer to an instance of the VkDebugMarkerMarkerInfoEXT structure specifying the parameters of the marker to insert.
33.3. Debug Report Callbacks
Debug report callbacks are represented by VkDebugReportCallbackEXT
handles:
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDebugReportCallbackEXT)
Debug report callbacks give more detailed feedback on the application’s use of Vulkan when events of interest occur.
To register a debug report callback, an application uses vkCreateDebugReportCallbackEXT.
VkResult vkCreateDebugReportCallbackEXT(
VkInstance instance,
const VkDebugReportCallbackCreateInfoEXT* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkDebugReportCallbackEXT* pCallback);
-
instancethe instance the callback will be logged on. -
pCreateInfopoints to a VkDebugReportCallbackCreateInfoEXT structure which defines the conditions under which this callback will be called. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter. -
pCallbackis a pointer to record theVkDebugReportCallbackEXTobject created.
The definition of VkDebugReportCallbackCreateInfoEXT is:
typedef struct VkDebugReportCallbackCreateInfoEXT {
VkStructureType sType;
const void* pNext;
VkDebugReportFlagsEXT flags;
PFN_vkDebugReportCallbackEXT pfnCallback;
void* pUserData;
} VkDebugReportCallbackCreateInfoEXT;
-
sTypeis the type of this structure. -
pNextisNULLor a pointer to an extension-specific structure. -
flagsis a bitmask of VkDebugReportFlagBitsEXT specifying which event(s) will cause this callback to be called. -
pfnCallbackis the application callback function to call. -
pUserDatais user data to be passed to the callback.
For each VkDebugReportCallbackEXT that is created the
VkDebugReportCallbackCreateInfoEXT::flags determine when that
VkDebugReportCallbackCreateInfoEXT::pfnCallback is called.
When an event happens, the implementation will do a bitwise AND of the
event’s VkDebugReportFlagBitsEXT flags to each
VkDebugReportCallbackEXT object’s flags.
For each non-zero result the corresponding callback will be called.
The callback will come directly from the component that detected the event,
unless some other layer intercepts the calls for its own purposes (filter
them in a different way, log to a system error log, etc.).
An application may receive multiple callbacks if multiple
VkDebugReportCallbackEXT objects were created.
A callback will always be executed in the same thread as the originating
Vulkan call.
A callback may be called from multiple threads simultaneously (if the application is making Vulkan calls from multiple threads).
Bits which can be set in
VkDebugReportCallbackCreateInfoEXT::flags, specifying events
which cause a debug report, are:
typedef enum VkDebugReportFlagBitsEXT {
VK_DEBUG_REPORT_INFORMATION_BIT_EXT = 0x00000001,
VK_DEBUG_REPORT_WARNING_BIT_EXT = 0x00000002,
VK_DEBUG_REPORT_PERFORMANCE_WARNING_BIT_EXT = 0x00000004,
VK_DEBUG_REPORT_ERROR_BIT_EXT = 0x00000008,
VK_DEBUG_REPORT_DEBUG_BIT_EXT = 0x00000010,
} VkDebugReportFlagBitsEXT;
-
VK_DEBUG_REPORT_ERROR_BIT_EXTspecifies that an error that may cause undefined results, including an application crash. -
VK_DEBUG_REPORT_WARNING_BIT_EXTspecifies use of Vulkan that may expose an app bug. Such cases may not be immediately harmful, such as a fragment shader outputting to a location with no attachment. Other cases may point to behavior that is almost certainly bad when unintended such as using an image whose memory has not been filled. In general if you see a warning but you know that the behavior is intended/desired, then simply ignore the warning. -
VK_DEBUG_REPORT_PERFORMANCE_WARNING_BIT_EXTspecifies a potentially non-optimal use of Vulkan, e.g. using vkCmdClearColorImage when setting VkAttachmentDescription::loadOptoVK_ATTACHMENT_LOAD_OP_CLEARwould have worked. -
VK_DEBUG_REPORT_INFORMATION_BIT_EXTspecifies an informational message such as resource details that may be handy when debugging an application. -
VK_DEBUG_REPORT_DEBUG_BIT_EXTspecifies diagnostic information from the implementation and layers.
typedef VkFlags VkDebugReportFlagsEXT;
VkDebugReportFlagsEXT is a bitmask type for setting a mask of zero or
more VkDebugReportFlagBitsEXT.
The prototype for the
VkDebugReportCallbackCreateInfoEXT::pfnCallback function
implemented by the application is:
typedef VkBool32 (VKAPI_PTR *PFN_vkDebugReportCallbackEXT)(
VkDebugReportFlagsEXT flags,
VkDebugReportObjectTypeEXT objectType,
uint64_t object,
size_t location,
int32_t messageCode,
const char* pLayerPrefix,
const char* pMessage,
void* pUserData);
-
flagsspecifies the VkDebugReportFlagBitsEXT that triggered this callback. -
objectTypeis a VkDebugReportObjectTypeEXT value specifying the type of object being used or created at the time the event was triggered. -
objectis the object where the issue was detected. IfobjectTypeisVK_DEBUG_REPORT_OBJECT_TYPE_UNKNOWN_EXT,objectis undefined. -
locationis a component (layer, driver, loader) defined value that specifies the location of the trigger. This is an optional value. -
messageCodeis a layer-defined value indicating what test triggered this callback. -
pLayerPrefixis a null-terminated string that is an abbreviation of the name of the component making the callback.pLayerPrefixis only valid for the duration of the callback. -
pMessageis a null-terminated string detailing the trigger conditions.pMessageis only valid for the duration of the callback. -
pUserDatais the user data given when the VkDebugReportCallbackEXT was created.
The callback must not call vkDestroyDebugReportCallbackEXT.
The callback returns a VkBool32, which is interpreted in a
layer-specified manner.
The application should always return VK_FALSE.
The VK_TRUE value is reserved for use in layer development.
object must be a Vulkan object or VK_NULL_HANDLE.
If objectType is not VK_DEBUG_REPORT_OBJECT_TYPE_UNKNOWN_EXT and
object is not VK_NULL_HANDLE, object must be a Vulkan
object of the corresponding type associated with objectType as defined
in VkDebugReportObjectTypeEXT and Vulkan Handle Relationship.
Possible values passed to the objectType parameter of the callback
function specified by
VkDebugReportCallbackCreateInfoEXT::pfnCallback, specifying the
type of object handle being reported, are:
typedef enum VkDebugReportObjectTypeEXT {
VK_DEBUG_REPORT_OBJECT_TYPE_UNKNOWN_EXT = 0,
VK_DEBUG_REPORT_OBJECT_TYPE_INSTANCE_EXT = 1,
VK_DEBUG_REPORT_OBJECT_TYPE_PHYSICAL_DEVICE_EXT = 2,
VK_DEBUG_REPORT_OBJECT_TYPE_DEVICE_EXT = 3,
VK_DEBUG_REPORT_OBJECT_TYPE_QUEUE_EXT = 4,
VK_DEBUG_REPORT_OBJECT_TYPE_SEMAPHORE_EXT = 5,
VK_DEBUG_REPORT_OBJECT_TYPE_COMMAND_BUFFER_EXT = 6,
VK_DEBUG_REPORT_OBJECT_TYPE_FENCE_EXT = 7,
VK_DEBUG_REPORT_OBJECT_TYPE_DEVICE_MEMORY_EXT = 8,
VK_DEBUG_REPORT_OBJECT_TYPE_BUFFER_EXT = 9,
VK_DEBUG_REPORT_OBJECT_TYPE_IMAGE_EXT = 10,
VK_DEBUG_REPORT_OBJECT_TYPE_EVENT_EXT = 11,
VK_DEBUG_REPORT_OBJECT_TYPE_QUERY_POOL_EXT = 12,
VK_DEBUG_REPORT_OBJECT_TYPE_BUFFER_VIEW_EXT = 13,
VK_DEBUG_REPORT_OBJECT_TYPE_IMAGE_VIEW_EXT = 14,
VK_DEBUG_REPORT_OBJECT_TYPE_SHADER_MODULE_EXT = 15,
VK_DEBUG_REPORT_OBJECT_TYPE_PIPELINE_CACHE_EXT = 16,
VK_DEBUG_REPORT_OBJECT_TYPE_PIPELINE_LAYOUT_EXT = 17,
VK_DEBUG_REPORT_OBJECT_TYPE_RENDER_PASS_EXT = 18,
VK_DEBUG_REPORT_OBJECT_TYPE_PIPELINE_EXT = 19,
VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_SET_LAYOUT_EXT = 20,
VK_DEBUG_REPORT_OBJECT_TYPE_SAMPLER_EXT = 21,
VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_POOL_EXT = 22,
VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_SET_EXT = 23,
VK_DEBUG_REPORT_OBJECT_TYPE_FRAMEBUFFER_EXT = 24,
VK_DEBUG_REPORT_OBJECT_TYPE_COMMAND_POOL_EXT = 25,
VK_DEBUG_REPORT_OBJECT_TYPE_SURFACE_KHR_EXT = 26,
VK_DEBUG_REPORT_OBJECT_TYPE_SWAPCHAIN_KHR_EXT = 27,
VK_DEBUG_REPORT_OBJECT_TYPE_DEBUG_REPORT_CALLBACK_EXT_EXT = 28,
VK_DEBUG_REPORT_OBJECT_TYPE_DISPLAY_KHR_EXT = 29,
VK_DEBUG_REPORT_OBJECT_TYPE_DISPLAY_MODE_KHR_EXT = 30,
VK_DEBUG_REPORT_OBJECT_TYPE_OBJECT_TABLE_NVX_EXT = 31,
VK_DEBUG_REPORT_OBJECT_TYPE_INDIRECT_COMMANDS_LAYOUT_NVX_EXT = 32,
VK_DEBUG_REPORT_OBJECT_TYPE_VALIDATION_CACHE_EXT_EXT = 33,
VK_DEBUG_REPORT_OBJECT_TYPE_SAMPLER_YCBCR_CONVERSION_EXT = 1000156000,
VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_EXT = 1000085000,
VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_KHR_EXT = VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_EXT,
VK_DEBUG_REPORT_OBJECT_TYPE_SAMPLER_YCBCR_CONVERSION_KHR_EXT = VK_DEBUG_REPORT_OBJECT_TYPE_SAMPLER_YCBCR_CONVERSION_EXT,
} VkDebugReportObjectTypeEXT;
| VkDebugReportObjectTypeEXT | Vulkan Handle Type |
|---|---|
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Unknown/Undefined Handle |
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Note
The primary expected use of |
To inject its own messages into the debug stream, call:
void vkDebugReportMessageEXT(
VkInstance instance,
VkDebugReportFlagsEXT flags,
VkDebugReportObjectTypeEXT objectType,
uint64_t object,
size_t location,
int32_t messageCode,
const char* pLayerPrefix,
const char* pMessage);
-
instanceis the debug stream’sVkInstance. -
flagsspecifies the VkDebugReportFlagBitsEXT classification of this event/message. -
objectTypeis a VkDebugReportObjectTypeEXT specifying the type of object being used or created at the time the event was triggered. -
objectthis is the object where the issue was detected.objectcan beVK_NULL_HANDLEif there is no object associated with the event. -
locationis an application defined value. -
messageCodeis an application defined value. -
pLayerPrefixis the abbreviation of the component making this event/message. -
pMessageis a null-terminated string detailing the trigger conditions.
The call will propagate through the layers and generate callback(s) as
indicated by the message’s flags.
The parameters are passed on to the callback in addition to the
pUserData value that was defined at the time the callback was
registered.
To destroy a VkDebugReportCallbackEXT object, call:
void vkDestroyDebugReportCallbackEXT(
VkInstance instance,
VkDebugReportCallbackEXT callback,
const VkAllocationCallbacks* pAllocator);
-
instancethe instance where the callback was created. -
callbacktheVkDebugReportCallbackEXTobject to destroy.callbackis an externally synchronized object and must not be used on more than one thread at a time. This means thatvkDestroyDebugReportCallbackEXTmust not be called when a callback is active. -
pAllocatorcontrols host memory allocation as described in the Memory Allocation chapter.
Appendix A: Vulkan Environment for SPIR-V
Shaders for Vulkan are defined by the Khronos SPIR-V Specification as well as the Khronos SPIR-V Extended Instructions for GLSL Specification. This appendix defines additional SPIR-V requirements applying to Vulkan shaders.
Versions and Formats
A Vulkan 1.1 implementation must support the 1.0, 1.1, 1.2, and 1.3 versions of SPIR-V and the 1.0 version of the SPIR-V Extended Instructions for GLSL.
A SPIR-V module passed into vkCreateShaderModule is interpreted as a series of 32-bit words in host endianness, with literal strings packed as described in section 2.2 of the SPIR-V Specification. The first few words of the SPIR-V module must be a magic number and a SPIR-V version number, as described in section 2.3 of the SPIR-V Specification.
Capabilities
Implementations must support the following capability operands declared by
OpCapability:
If the implementation supports any of the optional features described in the Features chapter, then the capability operand(s) corresponding to that feature must also be supported.
| SPIR-V OpCapability | Vulkan feature or extension name |
|---|---|
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The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_KHR_variable_pointers SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_AMD_shader_explicit_vertex_parameter SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_AMD_gcn_shader SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_AMD_gpu_shader_half_float SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_AMD_gpu_shader_int16 SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_AMD_shader_ballot SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_AMD_shader_fragment_mask SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_AMD_shader_image_load_store_lod SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_AMD_shader_trinary_minmax SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_AMD_texture_gather_bias_lod SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_KHR_shader_draw_parameters SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the
SPV_KHR_16bit_storage
SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the
SPV_KHR_storage_buffer_storage_class
SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_KHR_post_depth_coverage SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_EXT_shader_stencil_export SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_KHR_shader_ballot SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_KHR_subgroup_vote SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_NV_sample_mask_override_coverage SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_NV_geometry_shader_passthrough SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_NV_viewport_array2 SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_EXT_shader_viewport_index_layer SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that
uses the SPV_NVX_multiview_per_view_attributes SPIR-V extension.
The application can pass a SPIR-V module to vkCreateShaderModule that uses the SPV_EXT_descriptor_indexing SPIR-V extension.
The application must not pass a SPIR-V module containing any of the following to vkCreateShaderModule:
-
any OpCapability not listed above,
-
an unsupported capability, or
-
a capability which corresponds to a Vulkan feature or extension which has not been enabled.
Validation Rules within a Module
A SPIR-V module passed to vkCreateShaderModule must conform to the following rules:
-
Every entry point must have no return value and accept no arguments.
-
Recursion: The static function-call graph for an entry point must not contain cycles.
-
The Logical addressing model must be selected.
-
Scope for execution must be limited to:
-
Workgroup
-
Subgroup
-
-
Scope for memory must be limited to:
-
Device
-
Workgroup
-
Subgroup
-
Invocation
-
-
Scope for Non Uniform Group Operations must be limited to:
-
Subgroup
-
-
Storage Class must be limited to:
-
UniformConstant
-
Input
-
Uniform
-
Output
-
Workgroup
-
Private
-
Function
-
PushConstant
-
Image
-
StorageBuffer
-
-
Memory semantics must obey the following rules:
-
Acquire must not be used with
OpAtomicStore. -
Release must not be used with
OpAtomicLoad. -
AcquireRelease must not be used with
OpAtomicStoreorOpAtomicLoad. -
Sequentially consistent atomics and barriers are not supported and SequentiallyConsistent is treated as AcquireRelease. SequentiallyConsistent should not be used.
-
OpMemoryBarriermust use one of Acquire, Release, AcquireRelease, or SequentiallyConsistent and must include at least one storage class. -
If the semantics for
OpControlBarrierincludes one of Acquire, Release, AcquireRelease, or SequentiallyConsistent, then it must include at least one storage class. -
SubgroupMemory, CrossWorkgroupMemory, and AtomicCounterMemory are ignored.
-
-
Any
OpVariablewith anInitializeroperand must have one of the following as itsStorageClassoperand:-
Output
-
Private
-
Function
-
-
The
OriginLowerLeftexecution mode must not be used; fragment entry points must declareOriginUpperLeft. -
The
PixelCenterIntegerexecution mode must not be used. Pixels are always centered at half-integer coordinates. -
Images
-
OpTypeImagemust declare a scalar 32-bit float or 32-bit integer type for the “Sampled Type”. (RelaxedPrecisioncan be applied to a sampling instruction and to the variable holding the result of a sampling instruction.) -
OpTypeImagemust have a “Sampled” operand of 1 (sampled image) or 2 (storage image). -
If shaderStorageImageReadWithoutFormat is not enabled and an
OpTypeImagehas “Image Format” operand ofUnknown, any variables created with the given type must be decorated withNonReadable. -
If shaderStorageImageWriteWithoutFormat is not enabled and an
OpTypeImagehas “Image Format” operand ofUnknown, any variables created with the given type must be decorated withNonWriteable. -
OpImageQuerySizeLod, andOpImageQueryLevelsmust only consume an “Image” operand whose type has its “Sampled” operand set to 1. -
The (u,v) coordinates used for a
SubpassDatamust be the <id> of a constant vector (0,0), or if a layer coordinate is used, must be a vector that was formed with constant 0 for the u and v components. -
The “Depth” operand of
OpTypeImageis ignored.
-
-
Decorations
-
The
GLSLSharedandGLSLPackeddecorations must not be used. -
The
Flat,NoPerspective,Sample, andCentroiddecorations must not be used on variables with storage class other thanInputor on variables used in the interface of non-fragment shader entry points. -
The
Patchdecoration must not be used on variables in the interface of a vertex, geometry, or fragment shader stage’s entry point. -
The
ViewportRelativeNVdecoration must only be used on a variable decorated withLayerin the vertex, tessellation evaluation, or geometry shader stages. -
The
ViewportRelativeNVdecoration must not be used unless a variable decorated with one ofViewportIndexorViewportMaskNVis also statically used by the sameOpEntryPoint. -
The
ViewportMaskNVandViewportIndexdecorations must not both be statically used by one or moreOpEntryPoint’s that form the vertex processing stages of a graphics pipeline. -
Only the round-to-nearest-even and the round-to-zero rounding modes can be used for the
FPRoundingModedecoration. -
The
FPRoundingModedecoration can only be used for the floating-point conversion instructions as described in theSPV_KHR_16bit_storageSPIR-V extension.
-
-
OpTypeRuntimeArraymust only be used for:-
the last member of an
OpTypeStructthat is in theStorageBufferstorage class decorated asBlock, or that is in theUniformstorage class decorated asBufferBlock. -
If the
RuntimeDescriptorArrayEXTcapability is supported, an array of variables with storage classUniform,StorageBuffer, orUniformConstant, or for the outermost dimension of an array of arrays of such variables.
-
-
Linkage: See Shader Interfaces for additional linking and validation rules.
-
If
OpControlBarrieris used in fragment, vertex, tessellation evaluation, or geometry stages, the execution Scope must beSubgroup. -
Compute Shaders
-
For each compute shader entry point, either a
LocalSizeexecution mode or an object decorated with theWorkgroupSizedecoration must be specified.
-
-
“Result Type” for Non Uniform Group Operations must be limited to 32-bit float, 32-bit integer, boolean, or vectors of these types. If the
Float64capability is enabled, double and vector of double types are also permitted. -
“Mask” for
OpGroupNonUniformShuffleXormust be a specialization constant or a constant, or if the dynamic instance is called within a loop construct it must be one of:-
A specialization constant.
-
A constant.
-
An arthimetic operation whose operands are 1., 2., or 4.
-
A phi node whose operands are 1., 2., or 3.
-
-
If
OpGroupNonUniformBallotBitCountis used, the group operation must be one of:-
Reduce
-
InclusiveScan
-
ExclusiveScan
-
-
Atomic instructions must declare a scalar 32-bit integer type for the Result Type and the type of the value pointed to by Pointer.
-
If an instruction loads from or stores to a resource (including atomics and image instructions) and the resource descriptor being accessed is not dynamically uniform, then the operand corresponding to that resource (e.g. the pointer or sampled image operand) must be decorated with
NonUniformEXT.
Precision and Operation of SPIR-V Instructions
The following rules apply to both single and double-precision floating point instructions:
-
Positive and negative infinities and positive and negative zeros are generated as dictated by IEEE 754, but subject to the precisions allowed in the following table.
-
Dividing a non-zero by a zero results in the appropriately signed IEEE 754 infinity.
-
Any denormalized value input into a shader or potentially generated by any instruction in a shader may be flushed to 0.
-
The rounding mode cannot be set and is undefined.
-
NaNs may not be generated. Instructions that operate on a NaN may not result in a NaN.
-
Support for signaling NaNs is optional and exceptions are never raised.
The precision of double-precision instructions is at least that of single precision. For single precision (32 bit) instructions, precisions are required to be at least as follows, unless decorated with RelaxedPrecision:
| Instruction | Precision |
|---|---|
|
Correctly rounded. |
|
Correctly rounded. |
|
Correctly rounded. |
|
Correct result. |
|
Correct result. |
|
Correct result. |
|
Correct result. |
|
Correct result. |
|
2.5 ULP for b in the range [2-126, 2126]. |
conversions between types |
Correctly rounded. |
| Instruction | Precision |
|---|---|
|
Inherited from |
|
3 + 2 × |x| ULP. |
|
3 ULP outside the range [0.5, 2.0]. Absolute error < 2-21 inside the range [0.5, 2.0]. |
|
Inherited from |
|
Inherited from 1.0 / |
|
2 ULP. |
GLSL.std.450 extended instructions specifically defined in terms of the above instructions inherit the above errors. GLSL.std.450 extended instructions not listed above and not defined in terms of the above have undefined precision. These include, for example, the trigonometric functions and determinant.
For the OpSRem and OpSMod instructions, if either operand is
negative the result is undefined.
|
Note
While the |
Images which are read from or written to by shaders must have SPIR-V image formats compatible with the Vulkan image formats backing the image under the circumstances described for texture image validation. The compatibile formats are:
| SPIR-V Image Format | Compatible Vulkan Format |
|---|---|
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Appendix B: Compressed Image Formats
The compressed texture formats used by Vulkan are described in the specifically identified sections of the Khronos Data Format Specification, version 1.1.
Unless otherwise described, the quantities encoded in these compressed formats are treated as normalized, unsigned values.
Those formats listed as sRGB-encoded have in-memory representations of R, G and B components which are nonlinearly-encoded as R', G', and B'; any alpha component is unchanged. As part of filtering, the nonlinear R', G', and B' values are converted to linear R, G, and B components; any alpha component is unchanged. The conversion between linear and nonlinear encoding is performed as described in the “KHR_DF_TRANSFER_SRGB” section of the Khronos Data Format Specification.
Block-Compressed Image Formats
| VkFormat | Khronos Data Format Specification description |
|---|---|
Formats described in the “S3TC Compressed Texture Image Formats” chapter |
|
|
BC1 with no alpha |
|
BC1 with no alpha, sRGB-encoded |
|
BC1 with alpha |
|
BC1 with alpha, sRGB-encoded |
|
BC2 |
|
BC2, sRGB-encoded |
|
BC3 |
|
BC3, sRGB-encoded |
Formats described in the “RGTC Compressed Texture Image Formats” chapter |
|
|
BC4 unsigned |
|
BC4 signed |
|
BC5 unsigned |
|
BC5 signed |
Formats described in the “BPTC Compressed Texture Image Formats” chapter |
|
|
BC6H (unsigned version) |
|
BC6H (signed version) |
|
BC7 |
|
BC7, sRGB-encoded |
ETC Compressed Image Formats
The following formats are described in the “ETC2 Compressed Texture Image Formats” chapter of the Khronos Data Format Specification.
| VkFormat | Khronos Data Format Specification description |
|---|---|
|
RGB ETC2 |
|
RGB ETC2 with sRGB encoding |
|
RGB ETC2 with punch-through alpha |
|
RGB ETC2 with punch-through alpha and sRGB |
|
RGBA ETC2 |
|
RGBA ETC2 with sRGB encoding |
|
Unsigned R11 EAC |
|
Signed R11 EAC |
|
Unsigned RG11 EAC |
|
Signed RG11 EAC |
ASTC Compressed Image Formats
ASTC formats are described in the “ASTC Compressed Texture Image Formats” chapter of the Khronos Data Format Specification.
| VkFormat | Compressed texel block dimensions | sRGB-encoded |
|---|---|---|
|
4 × 4 |
No |
|
4 × 4 |
Yes |
|
5 × 4 |
No |
|
5 × 4 |
Yes |
|
5 × 5 |
No |
|
5 × 5 |
Yes |
|
6 × 5 |
No |
|
6 × 5 |
Yes |
|
6 × 6 |
No |
|
6 × 6 |
Yes |
|
8 × 5 |
No |
|
8 × 5 |
Yes |
|
8 × 6 |
No |
|
8 × 6 |
Yes |
|
8 × 8 |
No |
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8 × 8 |
Yes |
|
10 × 5 |
No |
|
10 × 5 |
Yes |
|
10 × 6 |
No |
|
10 × 6 |
Yes |
|
10 × 8 |
No |
|
10 × 8 |
Yes |
|
10 × 10 |
No |
|
10 × 10 |
Yes |
|
12 × 10 |
No |
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12 × 10 |
Yes |
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12 × 12 |
No |
|
12 × 12 |
Yes |
Appendix C: Core Revisions (Informative)
New minor versions of the Vulkan API are defined periodically by the Khronos Vulkan Working Group. These consist of some amount of additional functionality added to the core API, some of which may be promoted from extensions, other parts of which may be new. Extensions that are promoted in this way typically have their functionality replicated directly in the core, but with extension suffixes dropped. The existing values with suffixes are still present in the API itself as aliases of the original extension functionality. Any differences between the core and extension version of the functionality will be documented in the extension appendix, and mentioned briefly in the version description in this appendix.
It’s possible to build the specification for earlier versions, but to aid readability of the latest versions, this appendix gives an overview of the changes as compared to earlier versions.
Version 1.1
Vulkan Version 1.1 promoted a number of key extensions into the core API:
The only changes to the functionality added by these extensions were to
VK_KHR_shader_draw_parameters, which had a
feature bit added to determine
support in the core API, and
variablePointersStorageBuffer from VK_KHR_variable_pointers was
made optional.
Additionally, Vulkan 1.1 added support for subgroup operations, protected memory, and a new command to enumerate the instance version.
New Object Types
-
VkDescriptorUpdateTemplate
-
VkSamplerYcbcrConversion
New Defines
-
VK_API_VERSION_1_1
New Enum Constants
-
Extending VkBufferCreateFlagBits:
-
VK_BUFFER_CREATE_PROTECTED_BIT
-
-
Extending VkCommandPoolCreateFlagBits:
-
VK_COMMAND_POOL_CREATE_PROTECTED_BIT
-
-
Extending VkDependencyFlagBits:
-
VK_DEPENDENCY_DEVICE_GROUP_BIT -
VK_DEPENDENCY_VIEW_LOCAL_BIT
-
-
Extending VkDeviceQueueCreateFlagBits:
-
VK_DEVICE_QUEUE_CREATE_PROTECTED_BIT
-
-
Extending VkFormat:
-
VK_FORMAT_G8B8G8R8_422_UNORM -
VK_FORMAT_B8G8R8G8_422_UNORM -
VK_FORMAT_G8_B8_R8_3PLANE_420_UNORM -
VK_FORMAT_G8_B8R8_2PLANE_420_UNORM -
VK_FORMAT_G8_B8_R8_3PLANE_422_UNORM -
VK_FORMAT_G8_B8R8_2PLANE_422_UNORM -
VK_FORMAT_G8_B8_R8_3PLANE_444_UNORM -
VK_FORMAT_R10X6_UNORM_PACK16 -
VK_FORMAT_R10X6G10X6_UNORM_2PACK16 -
VK_FORMAT_R10X6G10X6B10X6A10X6_UNORM_4PACK16 -
VK_FORMAT_G10X6B10X6G10X6R10X6_422_UNORM_4PACK16 -
VK_FORMAT_B10X6G10X6R10X6G10X6_422_UNORM_4PACK16 -
VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_420_UNORM_3PACK16 -
VK_FORMAT_G10X6_B10X6R10X6_2PLANE_420_UNORM_3PACK16 -
VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_422_UNORM_3PACK16 -
VK_FORMAT_G10X6_B10X6R10X6_2PLANE_422_UNORM_3PACK16 -
VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_444_UNORM_3PACK16 -
VK_FORMAT_R12X4_UNORM_PACK16 -
VK_FORMAT_R12X4G12X4_UNORM_2PACK16 -
VK_FORMAT_R12X4G12X4B12X4A12X4_UNORM_4PACK16 -
VK_FORMAT_G12X4B12X4G12X4R12X4_422_UNORM_4PACK16 -
VK_FORMAT_B12X4G12X4R12X4G12X4_422_UNORM_4PACK16 -
VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_420_UNORM_3PACK16 -
VK_FORMAT_G12X4_B12X4R12X4_2PLANE_420_UNORM_3PACK16 -
VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_422_UNORM_3PACK16 -
VK_FORMAT_G12X4_B12X4R12X4_2PLANE_422_UNORM_3PACK16 -
VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_444_UNORM_3PACK16 -
VK_FORMAT_G16B16G16R16_422_UNORM -
VK_FORMAT_B16G16R16G16_422_UNORM -
VK_FORMAT_G16_B16_R16_3PLANE_420_UNORM -
VK_FORMAT_G16_B16R16_2PLANE_420_UNORM -
VK_FORMAT_G16_B16_R16_3PLANE_422_UNORM -
VK_FORMAT_G16_B16R16_2PLANE_422_UNORM -
VK_FORMAT_G16_B16_R16_3PLANE_444_UNORM
-
-
Extending VkFormatFeatureFlagBits:
-
VK_FORMAT_FEATURE_TRANSFER_SRC_BIT -
VK_FORMAT_FEATURE_TRANSFER_DST_BIT -
VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT -
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BIT -
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_SEPARATE_RECONSTRUCTION_FILTER_BIT -
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT -
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_FORCEABLE_BIT -
VK_FORMAT_FEATURE_DISJOINT_BIT -
VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT
-
-
Extending VkImageAspectFlagBits:
-
VK_IMAGE_ASPECT_PLANE_0_BIT -
VK_IMAGE_ASPECT_PLANE_1_BIT -
VK_IMAGE_ASPECT_PLANE_2_BIT
-
-
Extending VkImageCreateFlagBits:
-
VK_IMAGE_CREATE_ALIAS_BIT -
VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT -
VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT -
VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT -
VK_IMAGE_CREATE_EXTENDED_USAGE_BIT -
VK_IMAGE_CREATE_PROTECTED_BIT -
VK_IMAGE_CREATE_DISJOINT_BIT
-
-
Extending VkImageCreateFlagBits:
-
VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL -
VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL
-
-
Extending VkMemoryHeapFlagBits:
-
VK_MEMORY_HEAP_MULTI_INSTANCE_BIT
-
-
Extending VkMemoryPropertyFlagBits:
-
VK_MEMORY_PROPERTY_PROTECTED_BIT
-
-
Extending VkObjectType:
-
VK_OBJECT_TYPE_SAMPLER_YCBCR_CONVERSION -
VK_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE
-
-
Extending VkPipelineCreateFlagBits:
-
VK_PIPELINE_CREATE_VIEW_INDEX_FROM_DEVICE_INDEX_BIT -
VK_PIPELINE_CREATE_DISPATCH_BASE
-
-
Extending VkQueueFlagBits:
-
VK_QUEUE_PROTECTED_BIT
-
-
Extending VkResult:
-
VK_ERROR_OUT_OF_POOL_MEMORY -
VK_ERROR_INVALID_EXTERNAL_HANDLE
-
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SUBGROUP_PROPERTIES -
VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_INFO -
VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_INFO -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_16BIT_STORAGE_FEATURES -
VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS -
VK_STRUCTURE_TYPE_MEMORY_DEDICATED_ALLOCATE_INFO -
VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_FLAGS_INFO -
VK_STRUCTURE_TYPE_DEVICE_GROUP_RENDER_PASS_BEGIN_INFO -
VK_STRUCTURE_TYPE_DEVICE_GROUP_COMMAND_BUFFER_BEGIN_INFO -
VK_STRUCTURE_TYPE_DEVICE_GROUP_SUBMIT_INFO -
VK_STRUCTURE_TYPE_DEVICE_GROUP_BIND_SPARSE_INFO -
VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_DEVICE_GROUP_INFO -
VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_DEVICE_GROUP_INFO -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_GROUP_PROPERTIES -
VK_STRUCTURE_TYPE_DEVICE_GROUP_DEVICE_CREATE_INFO -
VK_STRUCTURE_TYPE_BUFFER_MEMORY_REQUIREMENTS_INFO_2 -
VK_STRUCTURE_TYPE_IMAGE_MEMORY_REQUIREMENTS_INFO_2 -
VK_STRUCTURE_TYPE_IMAGE_SPARSE_MEMORY_REQUIREMENTS_INFO_2 -
VK_STRUCTURE_TYPE_MEMORY_REQUIREMENTS_2 -
VK_STRUCTURE_TYPE_SPARSE_IMAGE_MEMORY_REQUIREMENTS_2 -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FEATURES_2 -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2 -
VK_STRUCTURE_TYPE_FORMAT_PROPERTIES_2 -
VK_STRUCTURE_TYPE_IMAGE_FORMAT_PROPERTIES_2 -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_FORMAT_INFO_2 -
VK_STRUCTURE_TYPE_QUEUE_FAMILY_PROPERTIES_2 -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PROPERTIES_2 -
VK_STRUCTURE_TYPE_SPARSE_IMAGE_FORMAT_PROPERTIES_2 -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SPARSE_IMAGE_FORMAT_INFO_2 -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_POINT_CLIPPING_PROPERTIES -
VK_STRUCTURE_TYPE_RENDER_PASS_INPUT_ATTACHMENT_ASPECT_CREATE_INFO -
VK_STRUCTURE_TYPE_IMAGE_VIEW_USAGE_CREATE_INFO -
VK_STRUCTURE_TYPE_PIPELINE_TESSELLATION_DOMAIN_ORIGIN_STATE_CREATE_INFO -
VK_STRUCTURE_TYPE_RENDER_PASS_MULTIVIEW_CREATE_INFO -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_FEATURES -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PROPERTIES -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTER_FEATURES -
VK_STRUCTURE_TYPE_PROTECTED_SUBMIT_INFO -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROTECTED_MEMORY_FEATURES -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROTECTED_MEMORY_PROPERTIES -
VK_STRUCTURE_TYPE_DEVICE_QUEUE_INFO_2 -
VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_CREATE_INFO -
VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_INFO -
VK_STRUCTURE_TYPE_BIND_IMAGE_PLANE_MEMORY_INFO -
VK_STRUCTURE_TYPE_IMAGE_PLANE_MEMORY_REQUIREMENTS_INFO -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLER_YCBCR_CONVERSION_FEATURES -
VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_IMAGE_FORMAT_PROPERTIES -
VK_STRUCTURE_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_CREATE_INFO -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_IMAGE_FORMAT_INFO -
VK_STRUCTURE_TYPE_EXTERNAL_IMAGE_FORMAT_PROPERTIES -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_BUFFER_INFO -
VK_STRUCTURE_TYPE_EXTERNAL_BUFFER_PROPERTIES -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ID_PROPERTIES -
VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_BUFFER_CREATE_INFO -
VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO -
VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_FENCE_INFO -
VK_STRUCTURE_TYPE_EXTERNAL_FENCE_PROPERTIES -
VK_STRUCTURE_TYPE_EXPORT_FENCE_CREATE_INFO -
VK_STRUCTURE_TYPE_EXPORT_SEMAPHORE_CREATE_INFO -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_SEMAPHORE_INFO -
VK_STRUCTURE_TYPE_EXTERNAL_SEMAPHORE_PROPERTIES -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MAINTENANCE_3_PROPERTIES -
VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_SUPPORT -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_DRAW_PARAMETER_FEATURES
-
New Enums
New Structures
New Functions
Appendix D: Layers & Extensions (Informative)
Extensions to the Vulkan API can be defined by authors, groups of authors, and the Khronos Vulkan Working Group. In order not to compromise the readability of the Vulkan Specification, the core Specification does not incorporate most extensions. The online Registry of extensions is available at URL
and allows generating versions of the Specification incorporating different extensions.
Most of the content previously in this appendix does not specify use of specific Vulkan extensions and layers, but rather specifies the processes by which extensions and layers are created. As of version 1.0.21 of the Vulkan Specification, this content has been migrated to the Vulkan Documentation and Extensions document. Authors creating extensions and layers must follow the mandatory procedures in that document.
The remainder of this appendix documents a set of extensions chosen when this document was built. Versions of the Specification published in the Registry include:
-
Core API + mandatory extensions required of all Vulkan implementations.
-
Core API + all registered and published Khronos (
KHR) extensions. -
Core API + all registered and published extensions.
Extensions are grouped as Khronos KHR, multivendor EXT, and then
alphabetically by author ID.
Within each group, extensions are listed in alphabetical order by their
name.
|
Note
As of the initial Vulkan 1.1 public release, the Some vendors may use an alternate author ID ending in |
VK_KHR_16bit_storage
- Name String
-
VK_KHR_16bit_storage - Extension Type
-
Device extension
- Registered Extension Number
-
84
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_storage_buffer_storage_class
-
- Contact
-
-
Jan-Harald Fredriksen @janharaldfredriksen-arm
-
- Last Modified Date
-
2017-09-05
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
This extension requires SPV_KHR_16bit_storage
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Alexander Galazin, ARM
-
Jan-Harald Fredriksen, ARM
-
Joerg Wagner, ARM
-
Neil Henning, Codeplay
-
Jeff Bolz, Nvidia
-
Daniel Koch, Nvidia
-
David Neto, Google
-
John Kessenich, Google
-
The VK_KHR_16bit_storage extension allows use of 16-bit types in shader
input and output interfaces, and push constant blocks.
This extension introduces several new optional features which map to SPIR-V
capabilities and allow access to 16-bit data in Block-decorated objects
in the Uniform and the StorageBuffer storage classes, and objects
in the PushConstant storage class.
This extension allows 16-bit variables to be declared and used as
user-defined shader inputs and outputs but does not change location
assignment and component assignment rules.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_16BIT_STORAGE_FEATURES_KHR
-
New Structures
New SPIR-V Capabilities
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Issues
Version History
-
Revision 1, 2017-03-23 (Alexander Galazin)
-
Initial draft
-
VK_KHR_android_surface
- Name String
-
VK_KHR_android_surface - Extension Type
-
Instance extension
- Registered Extension Number
-
9
- Revision
-
6
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_surface
-
- Contact
-
-
Jesse Hall @critsec
-
- Last Modified Date
-
2016-01-14
- IP Status
-
No known IP claims.
- Contributors
-
-
Patrick Doane, Blizzard
-
Jason Ekstrand, Intel
-
Ian Elliott, LunarG
-
Courtney Goeltzenleuchter, LunarG
-
Jesse Hall, Google
-
James Jones, NVIDIA
-
Antoine Labour, Google
-
Jon Leech, Khronos
-
David Mao, AMD
-
Norbert Nopper, Freescale
-
Alon Or-bach, Samsung
-
Daniel Rakos, AMD
-
Graham Sellers, AMD
-
Ray Smith, ARM
-
Jeff Vigil, Qualcomm
-
Chia-I Wu, LunarG
-
The VK_KHR_android_surface extension is an instance extension.
It provides a mechanism to create a VkSurfaceKHR object (defined by
the VK_KHR_surface extension) that refers to an ANativeWindow,
Android’s native surface type.
The ANativeWindow represents the producer endpoint of any buffer queue,
regardless of consumer endpoint.
Common consumer endpoints for ANativeWindows are the system window
compositor, video encoders, and application-specific compositors importing
the images through a SurfaceTexture.
New Object Types
None
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_ANDROID_SURFACE_CREATE_INFO_KHR
-
New Enums
None
New Structures
New Functions
Issues
1) Does Android need a way to query for compatibility between a particular physical device (and queue family?) and a specific Android display?
RESOLVED: No. Currently on Android, any physical device is expected to be able to present to the system compositor, and all queue families must support the necessary image layout transitions and synchronization operations.
Version History
-
Revision 1, 2015-09-23 (Jesse Hall)
-
Initial draft.
-
-
Revision 2, 2015-10-26 (Ian Elliott)
-
Renamed from VK_EXT_KHR_android_surface to VK_KHR_android_surface.
-
-
Revision 3, 2015-11-03 (Daniel Rakos)
-
Added allocation callbacks to surface creation function.
-
-
Revision 4, 2015-11-10 (Jesse Hall)
-
Removed VK_ERROR_INVALID_ANDROID_WINDOW_KHR.
-
-
Revision 5, 2015-11-28 (Daniel Rakos)
-
Updated the surface create function to take a pCreateInfo structure.
-
-
Revision 6, 2016-01-14 (James Jones)
-
Moved VK_ERROR_NATIVE_WINDOW_IN_USE_KHR from the VK_KHR_android_surface to the VK_KHR_surface extension.
-
VK_KHR_bind_memory2
- Name String
-
VK_KHR_bind_memory2 - Extension Type
-
Device extension
- Registered Extension Number
-
158
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Tobias Hector @tobski
-
- Last Modified Date
-
2017-09-05
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Jeff Bolz, NVIDIA
-
Tobias Hector, Imagination Technologies
-
This extension provides versions of vkBindBufferMemory and vkBindImageMemory that allow multiple bindings to be performed at once, and are extensible.
This extension also introduces VK_IMAGE_CREATE_ALIAS_BIT_KHR, which
allows “identical” images that alias the same memory to interpret the
contents consistently, even across image layout changes.
New Object Types
None.
New Enum Constants
-
Extending
VkStructureType:-
VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_INFO_KHR -
VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_INFO_KHR
-
-
Extending
VkImageCreateFlagBits:-
VK_IMAGE_CREATE_ALIAS_BIT_KHR
-
New Enums
None.
New Structures
New Functions
New Built-In Variables
None.
New SPIR-V Capabilities
None.
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Issues
None.
Version History
-
Revision 1, 2017-05-19 (Tobias Hector)
-
Pulled bind memory functions into their own extension
-
VK_KHR_dedicated_allocation
- Name String
-
VK_KHR_dedicated_allocation - Extension Type
-
Device extension
- Registered Extension Number
-
128
- Revision
-
3
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_get_memory_requirements2
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2017-09-05
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Jeff Bolz, NVIDIA
-
Jason Ekstrand, Intel
-
This extension enables resources to be bound to a dedicated allocation,
rather than suballocated.
For any particular resource, applications can query whether a dedicated
allocation is recommended, in which case using a dedicated allocation may
improve the performance of access to that resource.
Normal device memory allocations must support multiple resources per
allocation, memory aliasing and sparse binding, which could interfere with
some optimizations.
Applications should query the implementation for when a dedicated allocation
may be beneficial by adding VkMemoryDedicatedRequirementsKHR to the
pNext chain of the VkMemoryRequirements2 structure passed as the
pMemoryRequirements parameter to a call to
vkGetBufferMemoryRequirements2 or vkGetImageMemoryRequirements2.
Certain external handle types and external images or buffers may also
depend on dedicated allocations on implementations that associate image or
buffer metadata with OS-level memory objects.
This extension adds a two small structures to memory requirements querying and memory allocation: a new structure that flags whether an image/buffer should have a dedicated allocation, and a structure indicating the image or buffer that an allocation will be bound to.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS_KHR -
VK_STRUCTURE_TYPE_MEMORY_DEDICATED_ALLOCATE_INFO_KHR
-
New Enums
None.
New Structures
New Functions
None.
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Issues
None.
Examples
// Create an image with a dedicated allocation based on the
// implementation's preference
VkImageCreateInfo imageCreateInfo =
{
// Image creation parameters
};
VkImage image;
VkResult result = vkCreateImage(
device,
&imageCreateInfo,
NULL, // pAllocator
&image);
VkMemoryDedicatedRequirementsKHR dedicatedRequirements =
{
VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS_KHR,
NULL, // pNext
};
VkMemoryRequirements2 memoryRequirements =
{
VK_STRUCTURE_TYPE_MEMORY_REQUIREMENTS_2,
&dedicatedRequirements, // pNext
};
const VkImageMemoryRequirementsInfo2 imageRequirementsInfo =
{
VK_STRUCTURE_TYPE_IMAGE_MEMORY_REQUIREMENTS_INFO_2,
NULL, // pNext
image
};
vkGetImageMemoryRequirements2(
device,
&imageRequirementsInfo,
&memoryRequirements);
if (dedicatedRequirements.prefersDedicatedAllocation) {
// Allocate memory with VkMemoryDedicatedAllocateInfoKHR::image
// pointing to the image we are allocating the memory for
VkMemoryDedicatedAllocateInfoKHR dedicatedInfo =
{
VK_STRUCTURE_TYPE_MEMORY_DEDICATED_ALLOCATE_INFO_KHR, // sType
NULL, // pNext
image, // image
VK_NULL_HANDLE, // buffer
};
VkMemoryAllocateInfo memoryAllocateInfo =
{
VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO, // sType
&dedicatedInfo, // pNext
memoryRequirements.size, // allocationSize
FindMemoryTypeIndex(memoryRequirements.memoryTypeBits), // memoryTypeIndex
};
VkDeviceMemory memory;
vkAllocateMemory(
device,
&memoryAllocateInfo,
NULL, // pAllocator
&memory);
// Bind the image to the memory
vkBindImageMemory(
device,
image,
memory,
0);
} else {
// Take the normal memory sub-allocation path
}
Version History
-
Revision 1, 2017-02-27 (James Jones)
-
Copy content from VK_NV_dedicated_allocation
-
Add some references to external object interactions to the overview.
-
-
Revision 2, 2017-03-27 (Jason Ekstrand)
-
Rework the extension to be query-based
-
-
Revision 3, 2017-07-31 (Jason Ekstrand)
-
Clarify that memory objects created with VkMemoryDedicatedAllocateInfoKHR can only have the specified resource bound and no others.
-
VK_KHR_descriptor_update_template
- Name String
-
VK_KHR_descriptor_update_template - Extension Type
-
Device extension
- Registered Extension Number
-
86
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Markus Tavenrath @mtavenrath
-
- Last Modified Date
-
2017-09-05
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Interacts with
VK_KHR_push_descriptor -
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Jeff Bolz, NVIDIA
-
Michael Worcester, Imagination Technologies
-
Applications may wish to update a fixed set of descriptors in a large number of descriptors sets very frequently, i.e. during initializaton phase or if it’s required to rebuild descriptor sets for each frame. For those cases it’s also not unlikely that all information required to update a single descriptor set is stored in a single struct. This extension provides a way to update a fixed set of descriptors in a single VkDescriptorSet with a pointer to a user defined data structure which describes the new descriptors.
New Object Types
New Enum Constants
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_CREATE_INFO_KHR
New Functions
Promotion to Vulkan 1.1
vkCmdPushDescriptorSetWithTemplateKHR is included as an interaction
with VK_KHR_push_descriptor.
If Vulkan 1.1 and VK_KHR_push_descriptor are supported, this is included by
VK_KHR_push_descriptor.
The base functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Version History
-
Revision 1, 2016-01-11 (Markus Tavenrath)
-
Initial draft
-
VK_KHR_device_group
- Name String
-
VK_KHR_device_group - Extension Type
-
Device extension
- Registered Extension Number
-
61
- Revision
-
3
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_device_group_creation
-
- Contact
-
-
Jeff Bolz @jeffbolznv
-
- Last Modified Date
-
2017-10-06
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Jeff Bolz, NVIDIA
-
Tobias Hector, Imagination Technologies
-
This extension provides functionality to use a logical device that consists
of multiple physical devices, as created with the
VK_KHR_device_group_creation extension.
A device group can allocate memory across the subdevices, bind memory from
one subdevice to a resource on another subdevice, record command buffers
where some work executes on an arbitrary subset of the subdevices, and
potentially present a swapchain image from one or more subdevices.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_FLAGS_INFO_KHR -
VK_STRUCTURE_TYPE_DEVICE_GROUP_RENDER_PASS_BEGIN_INFO_KHR -
VK_STRUCTURE_TYPE_DEVICE_GROUP_COMMAND_BUFFER_BEGIN_INFO_KHR -
VK_STRUCTURE_TYPE_DEVICE_GROUP_SUBMIT_INFO_KHR -
VK_STRUCTURE_TYPE_DEVICE_GROUP_BIND_SPARSE_INFO_KHR -
VK_STRUCTURE_TYPE_DEVICE_GROUP_PRESENT_CAPABILITIES_KHR -
VK_STRUCTURE_TYPE_IMAGE_SWAPCHAIN_CREATE_INFO_KHR -
VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_SWAPCHAIN_INFO_KHR -
VK_STRUCTURE_TYPE_ACQUIRE_NEXT_IMAGE_INFO_KHR -
VK_STRUCTURE_TYPE_DEVICE_GROUP_PRESENT_INFO_KHR -
VK_STRUCTURE_TYPE_DEVICE_GROUP_SWAPCHAIN_CREATE_INFO_KHR -
VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_DEVICE_GROUP_INFO_KHR -
VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_DEVICE_GROUP_INFO_KHR
-
-
Extending VkImageCreateFlagBits
-
VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT_KHR
-
-
Extending VkPipelineCreateFlagBits
-
VK_PIPELINE_CREATE_VIEW_INDEX_FROM_DEVICE_INDEX_BIT_KHR -
VK_PIPELINE_CREATE_DISPATCH_BASE_KHR
-
-
Extending VkDependencyFlagBits
-
VK_DEPENDENCY_DEVICE_GROUP_BIT_KHR
-
-
Extending VkSwapchainCreateFlagBitsKHR
-
VK_SWAPCHAIN_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT_KHR
-
New Enums
New Structures
New Functions
New Built-In Variables
New SPIR-V Capabilities
Promotion to Vulkan 1.1
The following enums, types and commands are included as interactions with
VK_KHR_swapchain:
-
VK_STRUCTURE_TYPE_DEVICE_GROUP_PRESENT_CAPABILITIES_KHR -
VK_STRUCTURE_TYPE_IMAGE_SWAPCHAIN_CREATE_INFO_KHR -
VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_SWAPCHAIN_INFO_KHR -
VK_STRUCTURE_TYPE_ACQUIRE_NEXT_IMAGE_INFO_KHR -
VK_STRUCTURE_TYPE_DEVICE_GROUP_PRESENT_INFO_KHR -
VK_STRUCTURE_TYPE_DEVICE_GROUP_SWAPCHAIN_CREATE_INFO_KHR -
VK_SWAPCHAIN_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT_KHR
If Vulkan 1.1 and VK_KHR_swapchain are supported, these are included by VK_KHR_swapchain.
The base functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Issues
None.
Examples
TODO
Version History
-
Revision 1, 2016-10-19 (Jeff Bolz)
-
Internal revisions
-
-
Revision 2, 2017-05-19 (Tobias Hector)
-
Removed extended memory bind functions to VK_KHR_bind_memory2, added dependency on that extension, and device-group-specific structs for those functions.
-
-
Revision 3, 2017-10-06 (Ian Elliott)
-
Corrected Vulkan 1.1 interactions with the WSI extensions. All Vulkan 1.1 WSI interactions are with the VK_KHR_swapchain extension.
-
-
Revision 4, 2017-10-10 (Jeff Bolz)
-
Rename "SFR" bits and structure members to use the phrase "split instance bind regions".
-
VK_KHR_device_group_creation
- Name String
-
VK_KHR_device_group_creation - Extension Type
-
Instance extension
- Registered Extension Number
-
71
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Jeff Bolz @jeffbolznv
-
- Last Modified Date
-
2016-10-19
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Jeff Bolz, NVIDIA
-
This extension provides instance-level commands to enumerate groups of
physical devices, and to create a logical device from a subset of one of
those groups.
Such a logical device can then be used with new features in the
VK_KHR_device_group extension.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_GROUP_PROPERTIES_KHR
-
-
Extending VkMemoryHeapFlagBits
-
VK_MEMORY_HEAP_MULTI_INSTANCE_BIT_KHR
-
New Enums
None.
New Functions
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Issues
None.
Examples
VkDeviceCreateInfo devCreateInfo = { VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO };
// (not shown) fill out devCreateInfo as usual.
uint32_t deviceGroupCount = 0;
VkPhysicalDeviceGroupPropertiesKHR *props = NULL;
// Query the number of device groups
vkEnumeratePhysicalDeviceGroupsKHR(g_vkInstance, &deviceGroupCount, NULL);
// Allocate and initialize structures to query the device groups
props = (VkPhysicalDeviceGroupPropertiesKHR *)malloc(deviceGroupCount*sizeof(VkPhysicalDeviceGroupPropertiesKHR));
for (i = 0; i < deviceGroupCount; ++i) {
props[i].sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_GROUP_PROPERTIES_KHR;
props[i].pNext = NULL;
}
vkEnumeratePhysicalDeviceGroupsKHR(g_vkInstance, &deviceGroupCount, props);
// If the first device group has more than one physical device. create
// a logical device using all of the physical devices.
VkDeviceGroupDeviceCreateInfoKHR deviceGroupInfo = { VK_STRUCTURE_TYPE_DEVICE_GROUP_DEVICE_CREATE_INFO_KHR };
if (props[0].physicalDeviceCount > 1) {
deviceGroupInfo.physicalDeviceCount = props[0].physicalDeviceCount;
deviceGroupInfo.pPhysicalDevices = props[0].physicalDevices;
devCreateInfo.pNext = &deviceGroupInfo;
}
vkCreateDevice(props[0].physicalDevices[0], &devCreateInfo, NULL, &g_vkDevice);
free(props);
Version History
-
Revision 1, 2016-10-19 (Jeff Bolz)
-
Internal revisions
-
VK_KHR_display
- Name String
-
VK_KHR_display - Extension Type
-
Instance extension
- Registered Extension Number
-
3
- Revision
-
21
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_surface
-
- Contact
-
-
James Jones @cubanismo,Norbert Nopper @FslNopper
-
- Last Modified Date
-
2017-03-13
- IP Status
-
No known IP claims.
- Contributors
-
-
James Jones, NVIDIA
-
Norbert Nopper, Freescale
-
Jeff Vigil, Qualcomm
-
Daniel Rakos, AMD
-
This extension provides the API to enumerate displays and available modes on a given device.
New Object Types
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_DISPLAY_MODE_CREATE_INFO_KHR -
VK_STRUCTURE_TYPE_DISPLAY_SURFACE_CREATE_INFO_KHR
-
New Enums
New Structures
New Functions
Issues
1) Which properties of a mode should be fixed in the mode info vs. settable in some other function when setting the mode? E.g., do we need to double the size of the mode pool to include both stereo and non-stereo modes? YUV and RGB scanout even if they both take RGB input images? BGR vs. RGB input? etc.
PROPOSED RESOLUTION: Many modern displays support at most a handful of resolutions and timings natively. Other “modes” are expected to be supported using scaling hardware on the display engine or GPU. Other properties, such as rotation and mirroring should not require duplicating hardware modes just to express all combinations. Further, these properties may be implemented on a per-display or per-overlay granularity.
To avoid the exponential growth of modes as mutable properties are added, as
was the case with EGLConfig/WGL pixel formats/GLXFBConfig, this
specification should separate out hardware properties and configurable state
into separate objects.
Modes and overlay planes will express capabilities of the hardware, while a
separate structure will allow applications to configure scaling, rotation,
mirroring, color keys, LUT values, alpha masks, etc.
for a given swapchain independent of the mode in use.
Constraints on these settings will be established by properties of the
immutable objects.
Note the resolution of this issue may affect issue 5 as well.
2) What properties of a display itself are useful?
PROPOSED RESOLUTION: This issue is too broad. It was meant to prompt general discussion, but resolving this issue amounts to completing this specification. All interesting properties should be included. The issue will remain as a placeholder since removing it would make it hard to parse existing discussion notes that refer to issues by number.
3) How are multiple overlay planes within a display or mode enumerated?
PROPOSED RESOLUTION: They are referred to by an index. Each display will report the number of overlay planes it contains.
4) Should swapchains be created relative to a mode or a display?
PROPOSED RESOLUTION: When using this extension, swapchains are created relative to a mode and a plane. The mode implies the display object the swapchain will present to. If the specified mode is not the display’s current mode, the new mode will be applied when the first image is presented to the swapchain, and the default operating system mode, if any, will be restored when the swapchain is destroyed.
5) Should users query generic ranges from displays and construct their own modes explicitly using those constraints rather than querying a fixed set of modes (Most monitors only have one real “mode” these days, even though many support relatively arbitrary scaling, either on the monitor side or in the GPU display engine, making “modes” something of a relic/compatibility construct).
PROPOSED RESOLUTION: Expose both. Display info structures will expose a set of predefined modes, as well as any attributes necessary to construct a customized mode.
6) Is it fine if we return the display and display mode handles in the structure used to query their properties?
PROPOSED RESOLUTION: Yes.
7) Is there a possibility that not all displays of a device work with all of the present queues of a device? If yes, how do we determine which displays work with which present queues?
PROPOSED RESOLUTION: No known hardware has such limitations, but
determining such limitations is supported automatically using the existing
VK_KHR_surface and VK_KHR_swapchain query mechanisms.
8) Should all presentation need to be done relative to an overlay plane, or can a display mode + display be used alone to target an output?
PROPOSED RESOLUTION: Require specifying a plane explicitly.
9) Should displays have an associated window system display, such as an
HDC or Display*?
PROPOSED RESOLUTION: No.
Displays are independent of any windowing system in use on the system.
Further, neither HDC nor Display* refer to a physical display
object.
10) Are displays queried from a physical GPU or from a device instance?
PROPOSED RESOLUTION: Developers prefer to query modes directly from the physical GPU so they can use display information as an input to their device selection algorithms prior to device creation. This avoids the need to create dummy device instances to enumerate displays.
This preference must be weighed against the extra initialization that must be done by driver vendors prior to device instance creation to support this usage.
11) Should displays and/or modes be dispatchable objects? If functions are to take displays, overlays, or modes as their first parameter, they must be dispatchable objects as defined in Khronos bug 13529. If they are not added to the list of dispatchable objects, functions operating on them must take some higher-level object as their first parameter. There is no performance case against making them dispatchable objects, but they would be the first extension objects to be dispatchable.
PROPOSED RESOLUTION: Do not make displays or modes dispatchable. They will dispatch based on their associated physical device.
12) Should hardware cursor capabilities be exposed?
PROPOSED RESOLUTION: Defer. This could be a separate extension on top of the base WSI specs.
|
editing-note
There appears to be a missing sentence for the first part of issue 13 here. |
if they are one physical display device to an end user, but may internally be implemented as two side-by-side displays using the same display engine (and sometimes cabling) resources as two physically separate display devices.
RESOLVED: Tiled displays will appear as a single display object in this API.
14) Should the raw EDID data be included in the display information?
RESOLVED: No. A future extension could be added which reports the EDID if necessary. This may be complicated by the outcome of issue 13.
15) Should min and max scaling factor capabilities of overlays be exposed?
RESOLVED: Yes. This is exposed indirectly by allowing applications to query the min/max position and extent of the source and destination regions from which image contents are fetched by the display engine when using a particular mode and overlay pair.
16) Should devices be able to expose planes that can be moved between displays? If so, how?
RESOLVED: Yes. Applications can determine which displays a given plane supports using vkGetDisplayPlaneSupportedDisplaysKHR.
17) Should there be a way to destroy display modes? If so, does it support destroying “built in” modes?
RESOLVED: Not in this extension. A future extension could add this functionality.
18) What should the lifetime of display and built-in display mode objects be?
RESOLVED: The lifetime of the instance. These objects cannot be destroyed. A future extension may be added to expose a way to destroy these objects and/or support display hotplug.
19) Should persistent mode for smart panels be enabled/disabled at swapchain creation time, or on a per-present basis.
RESOLVED: On a per-present basis.
Examples
|
Note
The example code for the |
Version History
-
Revision 1, 2015-02-24 (James Jones)
-
Initial draft
-
-
Revision 2, 2015-03-12 (Norbert Nopper)
-
Added overlay enumeration for a display.
-
-
Revision 3, 2015-03-17 (Norbert Nopper)
-
Fixed typos and namings as discussed in Bugzilla.
-
Reordered and grouped functions.
-
Added functions to query count of display, mode and overlay.
-
Added native display handle, which is maybe needed on some platforms to create a native Window.
-
-
Revision 4, 2015-03-18 (Norbert Nopper)
-
Removed primary and virtualPostion members (see comment of James Jones in Bugzilla).
-
Added native overlay handle to info structure.
-
Replaced , with ; in struct.
-
-
Revision 6, 2015-03-18 (Daniel Rakos)
-
Added WSI extension suffix to all items.
-
Made the whole API more "Vulkanish".
-
Replaced all functions with a single vkGetDisplayInfoKHR function to better match the rest of the API.
-
Made the display, display mode, and overlay objects be first class objects, not subclasses of VkBaseObject as they do not support the common functions anyways.
-
Renamed *Info structures to *Properties.
-
Removed overlayIndex field from VkOverlayProperties as there is an implicit index already as a result of moving to a "Vulkanish" API.
-
Displays are not get through device, but through physical GPU to match the rest of the Vulkan API. Also this is something ISVs explicitly requested.
-
Added issue (6) and (7).
-
-
Revision 7, 2015-03-25 (James Jones)
-
Added an issues section
-
Added rotation and mirroring flags
-
-
Revision 8, 2015-03-25 (James Jones)
-
Combined the duplicate issues sections introduced in last change.
-
Added proposed resolutions to several issues.
-
-
Revision 9, 2015-04-01 (Daniel Rakos)
-
Rebased extension against Vulkan 0.82.0
-
-
Revision 10, 2015-04-01 (James Jones)
-
Added issues (10) and (11).
-
Added more straw-man issue resolutions, and cleaned up the proposed resolution for issue (4).
-
Updated the rotation and mirroring enums to have proper bitmask semantics.
-
-
Revision 11, 2015-04-15 (James Jones)
-
Added proposed resolution for issues (1) and (2).
-
Added issues (12), (13), (14), and (15)
-
Removed pNativeHandle field from overlay structure.
-
Fixed small compilation errors in example code.
-
-
Revision 12, 2015-07-29 (James Jones)
-
Rewrote the guts of the extension against the latest WSI swapchain specifications and the latest Vulkan API.
-
Address overlay planes by their index rather than an object handle and refer to them as "planes" rather than "overlays" to make it slightly clearer that even a display with no "overlays" still has at least one base "plane" that images can be displayed on.
-
Updated most of the issues.
-
Added an "extension type" section to the specification header.
-
Re-used the VK_EXT_KHR_surface surface transform enumerations rather than redefining them here.
-
Updated the example code to use the new semantics.
-
-
Revision 13, 2015-08-21 (Ian Elliott)
-
Renamed this extension and all of its enumerations, types, functions, etc. This makes it compliant with the proposed standard for Vulkan extensions.
-
Switched from "revision" to "version", including use of the VK_MAKE_VERSION macro in the header file.
-
-
Revision 14, 2015-09-01 (James Jones)
-
Restore single-field revision number.
-
-
Revision 15, 2015-09-08 (James Jones)
-
Added alpha flags enum.
-
Added premultiplied alpha support.
-
-
Revision 16, 2015-09-08 (James Jones)
-
Added description section to the spec.
-
Added issues 16 - 18.
-
-
Revision 17, 2015-10-02 (James Jones)
-
Planes are now a property of the entire device rather than individual displays. This allows planes to be moved between multiple displays on devices that support it.
-
Added a function to create a VkSurfaceKHR object describing a display plane and mode to align with the new per-platform surface creation conventions.
-
Removed detailed mode timing data. It was agreed that the mode extents and refresh rate are sufficient for current use cases. Other information could be added back2 in as an extension if it is needed in the future.
-
Added support for smart/persistent/buffered display devices.
-
-
Revision 18, 2015-10-26 (Ian Elliott)
-
Renamed from VK_EXT_KHR_display to VK_KHR_display.
-
-
Revision 19, 2015-11-02 (James Jones)
-
Updated example code to match revision 17 changes.
-
-
Revision 20, 2015-11-03 (Daniel Rakos)
-
Added allocation callbacks to creation functions.
-
-
Revision 21, 2015-11-10 (Jesse Hall)
-
Added VK_DISPLAY_PLANE_ALPHA_OPAQUE_BIT_KHR, and use VkDisplayPlaneAlphaFlagBitsKHR for VkDisplayPlanePropertiesKHR::alphaMode instead of VkDisplayPlaneAlphaFlagsKHR, since it only represents one mode.
-
Added reserved flags bitmask to VkDisplayPlanePropertiesKHR.
-
Use VkSurfaceTransformFlagBitsKHR instead of obsolete VkSurfaceTransformKHR.
-
Renamed vkGetDisplayPlaneSupportedDisplaysKHR parameters for clarity.
-
-
Revision 22, 2015-12-18 (James Jones)
-
Added missing "planeIndex" parameter to vkGetDisplayPlaneSupportedDisplaysKHR()
-
-
Revision 23, 2017-03-13 (James Jones)
-
Closed all remaining issues. The specification and implementations have been shipping with the proposed resolutions for some time now.
-
Removed the sample code and noted it has been integrated into the official Vulkan SDK cube demo.
-
VK_KHR_display_swapchain
- Name String
-
VK_KHR_display_swapchain - Extension Type
-
Device extension
- Registered Extension Number
-
4
- Revision
-
9
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_swapchain -
Requires
VK_KHR_display
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2017-03-13
- IP Status
-
No known IP claims.
- Contributors
-
-
James Jones, NVIDIA
-
Jeff Vigil, Qualcomm
-
Jesse Hall, Google
-
This extension provides an API to create a swapchain directly on a device’s display without any underlying window system.
New Object Types
None
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_DISPLAY_PRESENT_INFO_KHR
-
-
Extending VkResult:
-
VK_ERROR_INCOMPATIBLE_DISPLAY_KHR
-
New Enums
None
New Structures
New Functions
Issues
1) Should swapchains sharing images each hold a reference to the images, or should it be up to the application to destroy the swapchains and images in an order that avoids the need for reference counting?
RESOLVED: Take a reference. The lifetime of presentable images is already complex enough.
2) Should the srcRect/dstRect parameters be specified as part of
the present command, or at swapchain creation time?
RESOLVED: As part of the presentation command. This allows moving and scaling the image on the screen without the need to respecify the mode or create a new swapchain and presentable images.
3) Should srcRect/dstRect be specified as rects, or separate
offset/extent values?
RESOLVED: As rects. Specifying them separately might make it easier for hardware to expose support for one but not the other, but in such cases applications must just take care to obey the reported capabilities and not use non-zero offsets or extents that require scaling, as appropriate.
4) How can applications create multiple swapchains that use the same images?
RESOLVED: By calling vkCreateSharedSwapchainsKHR.
An earlier resolution used vkCreateSwapchainKHR, chaining multiple
VkSwapchainCreateInfoKHR structures through pNext.
In order to allow each swapchain to also allow other extension structs, a
level of indirection was used: VkSwapchainCreateInfoKHR::pNext
pointed to a different structure, which had both an sType/pNext
for additional extensions, and also had a pointer to the next
VkSwapchainCreateInfoKHR structure.
The number of swapchains to be created could only be found by walking this
linked list of alternating structures, and the pSwapchains out
parameter was reinterpreted to be an array of VkSwapchainKHR handles.
Another option considered was a method to specify a “shared” swapchain when creating a new swapchain, such that groups of swapchains using the same images could be built up one at a time. This was deemed unusable because drivers need to know all of the displays an image will be used on when determining which internal formats and layouts to use for that image.
Examples
|
Note
The example code for the |
Version History
-
Revision 1, 2015-07-29 (James Jones)
-
Initial draft
-
-
Revision 2, 2015-08-21 (Ian Elliott)
-
Renamed this extension and all of its enumerations, types, functions, etc. This makes it compliant with the proposed standard for Vulkan extensions.
-
Switched from "revision" to "version", including use of the VK_MAKE_VERSION macro in the header file.
-
-
Revision 3, 2015-09-01 (James Jones)
-
Restore single-field revision number.
-
-
Revision 4, 2015-09-08 (James Jones)
-
Allow creating multiple swap chains that share the same images using a single call to vkCreateSwapChainKHR().
-
-
Revision 5, 2015-09-10 (Alon Or-bach)
-
Removed underscores from SWAP_CHAIN in two enums.
-
-
Revision 6, 2015-10-02 (James Jones)
-
Added support for smart panels/buffered displays.
-
-
Revision 7, 2015-10-26 (Ian Elliott)
-
Renamed from VK_EXT_KHR_display_swapchain to VK_KHR_display_swapchain.
-
-
Revision 8, 2015-11-03 (Daniel Rakos)
-
Updated sample code based on the changes to VK_KHR_swapchain.
-
-
Revision 9, 2015-11-10 (Jesse Hall)
-
Replaced VkDisplaySwapchainCreateInfoKHR with vkCreateSharedSwapchainsKHR, changing resolution of issue #4.
-
-
Revision 10, 2017-03-13 (James Jones)
-
Closed all remaining issues. The specification and implementations have been shipping with the proposed resolutions for some time now.
-
Removed the sample code and noted it has been integrated into the official Vulkan SDK cube demo.
-
VK_KHR_draw_indirect_count
- Name String
-
VK_KHR_draw_indirect_count - Extension Type
-
Device extension
- Registered Extension Number
-
170
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Piers Daniell @pdaniell-nv
-
- Status
-
Draft
- Last Modified Date
-
2017-08-25
- IP Status
-
No known IP claims.
- Contributors
-
-
Matthaeus G. Chajdas, AMD
-
Derrick Owens, AMD
-
Graham Sellers, AMD
-
Daniel Rakos, AMD
-
Dominik Witczak, AMD
-
Piers Daniell, NVIDIA
-
This extension is based off the VK_AMD_draw_indirect_count extension. This extension allows an application to source the number of draw calls for indirect draw calls from a buffer. This enables applications to generate arbitrary amounts of draw commands and execute them without host intervention.
New Functions
Version History
-
Revision 1, 2017-08-25 (Piers Daniell)
-
Initial draft based off VK_AMD_draw_indirect_count
-
VK_KHR_external_fence
- Name String
-
VK_KHR_external_fence - Extension Type
-
Device extension
- Registered Extension Number
-
114
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_external_fence_capabilities
-
- Contact
-
-
Jesse Hall @critsec
-
- Last Modified Date
-
2017-05-08
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Jesse Hall, Google
-
James Jones, NVIDIA
-
Jeff Juliano, NVIDIA
-
Cass Everitt, Oculus
-
Contributors to
VK_KHR_external_semaphore
-
An application using external memory may wish to synchronize access to that memory using fences. This extension enables an application to create fences from which non-Vulkan handles that reference the underlying synchronization primitive can be exported.
New Object Types
None.
New Enum Constants
-
VK_STRUCTURE_TYPE_EXPORT_FENCE_CREATE_INFO_KHR
New Enums
New Structs
New Functions
None.
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Issues
This extension borrows concepts, semantics, and language from
VK_KHR_external_semaphore.
That extension’s issues apply equally to this extension.
VK_KHR_external_fence_capabilities
- Name String
-
VK_KHR_external_fence_capabilities - Extension Type
-
Instance extension
- Registered Extension Number
-
113
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Jesse Hall @critsec
-
- Last Modified Date
-
2017-05-08
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Jesse Hall, Google
-
James Jones, NVIDIA
-
Jeff Juliano, NVIDIA
-
Cass Everitt, Oculus
-
Contributors to
VK_KHR_external_semaphore_capabilities
-
An application may wish to reference device fences in multiple Vulkan logical devices or instances, in multiple processes, and/or in multiple APIs. This extension provides a set of capability queries and handle definitions that allow an application to determine what types of “external” fence handles an implementation supports for a given set of use cases.
New Object Types
None.
New Enum Constants
-
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_FENCE_INFO_KHR -
VK_STRUCTURE_TYPE_EXTERNAL_FENCE_PROPERTIES_KHR -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ID_PROPERTIES_KHR -
VK_LUID_SIZE_KHR
New Structs
New Functions
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Issues
None.
VK_KHR_external_fence_fd
- Name String
-
VK_KHR_external_fence_fd - Extension Type
-
Device extension
- Registered Extension Number
-
116
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_external_fence
-
- Contact
-
-
Jesse Hall @critsec
-
- Last Modified Date
-
2017-05-08
- IP Status
-
No known IP claims.
- Contributors
-
-
Jesse Hall, Google
-
James Jones, NVIDIA
-
Jeff Juliano, NVIDIA
-
Cass Everitt, Oculus
-
Contributors to
VK_KHR_external_semaphore_fd
-
An application using external memory may wish to synchronize access to that memory using fences. This extension enables an application to export fence payload to and import fence payload from POSIX file descriptors.
New Object Types
None.
New Enum Constants
-
VK_STRUCTURE_TYPE_IMPORT_FENCE_FD_INFO_KHR -
VK_STRUCTURE_TYPE_FENCE_GET_FD_INFO_KHR
New Enums
None.
New Structs
New Functions
Issues
This extension borrows concepts, semantics, and language from
VK_KHR_external_semaphore_fd.
That extension’s issues apply equally to this extension.
VK_KHR_external_fence_win32
- Name String
-
VK_KHR_external_fence_win32 - Extension Type
-
Device extension
- Registered Extension Number
-
115
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_external_fence
-
- Contact
-
-
Jesse Hall @critsec
-
- Last Modified Date
-
2017-05-08
- IP Status
-
No known IP claims.
- Contributors
-
-
Jesse Hall, Google
-
James Jones, NVIDIA
-
Jeff Juliano, NVIDIA
-
Cass Everitt, Oculus
-
Contributors to
VK_KHR_external_semaphore_win32
-
An application using external memory may wish to synchronize access to that memory using fences. This extension enables an application to export fence payload to and import fence payload from Windows handles.
New Object Types
None.
New Enum Constants
-
VK_STRUCTURE_TYPE_IMPORT_FENCE_WIN32_HANDLE_INFO_KHR -
VK_STRUCTURE_TYPE_EXPORT_FENCE_WIN32_HANDLE_INFO_KHR -
VK_STRUCTURE_TYPE_FENCE_GET_WIN32_HANDLE_INFO_KHR
New Enums
None.
New Structs
New Functions
Issues
This extension borrows concepts, semantics, and language from
VK_KHR_external_semaphore_win32.
That extension’s issues apply equally to this extension.
1) Should D3D12 fence handle types be supported, like they are for semaphores?
RESOLVED: No.
Doing so would require extending the fence signal and wait operations to
provide values to signal / wait for, like VkD3D12FenceSubmitInfoKHR
does.
A D3D12 fence can be signaled by importing it into a VkSemaphore
instead of a VkFence, and applications can check status or wait on the
D3D12 fence using non-Vulkan APIs.
The convenience of being able to do these operations on VkFence
objects doesn’t justify the extra API complexity.
VK_KHR_external_memory
- Name String
-
VK_KHR_external_memory - Extension Type
-
Device extension
- Registered Extension Number
-
73
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_external_memory_capabilities
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2016-10-20
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Interacts with
VK_KHR_dedicated_allocation. -
Interacts with
VK_NV_dedicated_allocation. -
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Jason Ekstrand, Intel
-
Ian Elliot, Google
-
Jesse Hall, Google
-
Tobias Hector, Imagination Technologies
-
James Jones, NVIDIA
-
Jeff Juliano, NVIDIA
-
Matthew Netsch, Qualcomm Technologies, Inc.
-
Daniel Rakos, AMD
-
Carsten Rohde, NVIDIA
-
Ray Smith, ARM
-
Chad Versace, Google
-
An application may wish to reference device memory in multiple Vulkan logical devices or instances, in multiple processes, and/or in multiple APIs. This extension enables an application to export non-Vulkan handles from Vulkan memory objects such that the underlying resources can be referenced outside the scope of the Vulkan logical device that created them.
New Object Types
None.
New Enum Constants
-
VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_BUFFER_CREATE_INFO_KHR -
VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO_KHR -
VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO_KHR -
VK_QUEUE_FAMILY_EXTERNAL_KHR -
VK_ERROR_INVALID_EXTERNAL_HANDLE_KHR
New Enums
None.
New Structs
New Functions
None.
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Issues
1) How do applications correlate two physical devices across process or Vulkan instance boundaries?
RESOLVED: New device ID fields have been introduced by
VK_KHR_external_memory_capabilities.
These fields, combined with the existing
VkPhysicalDeviceProperties::driverVersion field can be used to
identify compatible devices across processes, drivers, and APIs.
VkPhysicalDeviceProperties::pipelineCacheUUID is not sufficient
for this purpose because despite its description in the specification, it
need only identify a unique pipeline cache format in practice.
Multiple devices may be able to use the same pipeline cache data, and hence
it would be desirable for all of them to have the same pipeline cache UUID.
However, only the same concrete physical device can be used when sharing
memory, so an actual unique device ID was introduced.
Further, the pipeline cache UUID was specific to Vulkan, but correlation
with other, non-extensible APIs is required to enable interoperation with
those APIs.
2) If memory objects are shared between processes and APIs, is this considered aliasing according to the rules outlined in the Memory Aliasing section?
RESOLVED: Yes. Applications must take care to obey all restrictions imposed on aliased resources when using memory across multiple Vulkan instances or other APIs.
3) Are new image layouts or metadata required to specify image layouts and layout transitions compatible with non-Vulkan APIs, or with other instances of the same Vulkan driver?
RESOLVED: Separate instances of the same Vulkan driver running on the same GPU should have identical internal layout semantics, so applications have the tools they need to ensure views of images are consistent between the two instances. Other APIs will fall into two categories: Those that are Vulkan- compatible, and those that are Vulkan-incompatible. Vulkan-incompatible APIs will require the image to be in the GENERAL layout whenever they are accessing them.
Note this does not attempt to address cross-device transitions, nor transitions to engines on the same device which are not visible within the Vulkan API. Both of these are beyond the scope of this extension.
4) Is a new barrier flag or operation of some type needed to prepare external memory for handoff to another Vulkan instance or API and/or receive it from another instance or API?
RESOLVED: Yes. Some implementations need to perform additional cache management when transitioning memory between address spaces, and other APIs, instances, or processes may operate in a separate address space. Options for defining this transition include:
-
A new structure that can be added to the
pNextlist in VkMemoryBarrier, VkBufferMemoryBarrier, and VkImageMemoryBarrier. -
A new bit in VkAccessFlags that can be set to indicate an “external” access.
-
A new bit in VkDependencyFlags
-
A new special queue family that represents an “external” queue.
A new structure has the advantage that the type of external transition can
be described in as much detail as necessary.
However, there is not currently a known need for anything beyond
differentiating external vs.
internal accesses, so this is likely an over-engineered solution.
The access flag bit has the advantage that it can be applied at buffer,
image, or global granularity, and semantically it maps pretty well to the
operation being described.
Additionally, the API already includes VK_ACCESS_MEMORY_READ_BIT and
VK_ACCESS_MEMORY_WRITE_BIT which appear to be intended for this
purpose.
However, there is no obvious pipeline stage that would correspond to an
external access, and therefore no clear way to use
VK_ACCESS_MEMORY_READ_BIT or VK_ACCESS_MEMORY_WRITE_BIT.
VkDependencyFlags and VkPipelineStageFlags operate at command
granularity rather than image or buffer granularity, which would make an
entire pipeline barrier an internal→external or external→internal barrier.
This may not be a problem in practice, but seems like the wrong scope.
Another downside of VkDependencyFlags is that it lacks inherent
directionality: There are not src and dst variants of it in the
barrier or dependency description semantics, so two bits might need to be
added to describe both internal→external and external→internal
transitions.
Transitioning a resource to a special queue family corresponds well with the
operation of transitioning to a separate Vulkan instance, in that both
operations ideally include scheduling a barrier on both sides of the
transition: Both the releasing and the acquiring queue or process.
Using a special queue family requires adding an additional reserved queue
family index.
Re-using VK_QUEUE_FAMILY_IGNORED would have left it unclear how to
transition a concurrent usage resource from one process to another, since
the semantics would have likely been equivalent to the currently-ignored
transition of
VK_QUEUE_FAMILY_IGNORED → VK_QUEUE_FAMILY_IGNORED.
Fortunately, creating a new reserved queue family index is not invasive.
Based on the above analysis, the approach of transitioning to a special “external” queue family was chosen.
5) Do internal driver memory arrangements and/or other internal driver image properties need to be exported and imported when sharing images across processes or APIs.
RESOLVED: Some vendors claim this is necessary on their implementations, but it was determined that the security risks of allowing opaque meta data to be passed from applications to the driver were too high. Therefore, implementations which require metadata will need to associate it with the objects represented by the external handles, and rely on the dedicated allocation mechanism to associate the exported and imported memory objects with a single image or buffer.
6) Most prior interoperation and cross-process sharing APIs have been based on image-level sharing. Should Vulkan sharing be based on memory-object sharing or image sharing?
RESOLVED: These extensions have assumed memory-level sharing is the correct granularity. Vulkan is a lower-level API than most prior APIs, and as such attempts to closely align with to the underlying primitives of the hardware and system-level drivers it abstracts. In general, the resource that holds the backing store for both images and buffers of various types is memory. Images and buffers are merely metadata containing brief descriptions of the layout of bits within that memory.
Because memory object-based sharing is aligned with the overall Vulkan API design, it exposes the full power of Vulkan on external objects. External memory can be used as backing for sparse images, for example, whereas such usage would be awkward at best with a sharing mechanism based on higher-level primitives such as images. Further, aligning the mechanism with the API in this way provides some hope of trivial compatibility with future API enhancements. If new objects backed by memory objects are added to the API, they too can be used across processes with minimal additions to the base external memory APIs.
Earlier APIs implemented interop at a higher level, and this necessitated entirely separate sharing APIs for images and buffers. To co-exist and interoperate with those APIs, the Vulkan external sharing mechanism must accomodate their model. However, if it can be agreed that memory-based sharing is the more desirable and forward-looking design, legacy interoperation considerations can be considered another reason to favor memory-based sharing: While native and legacy driver primitives that may be used to implement sharing may not be as low-level as the API here suggests, raw memory is still the least common denominator among the types. Image-based sharing can be cleanly derived from a set of base memory- object sharing APIs with minimal effort, whereas image-based sharing does not generalize well to buffer or raw-memory sharing. Therefore, following the general Vulkan design principle of minimalism, it is better to expose even interopability with image-based native and external primitives via the memory sharing API, and place sufficient limits on their usage to ensure they can be used only as backing for equivalent Vulkan images. This provides a consistent API for applications regardless of which platform or external API they are targeting, which makes development of multi-API and multi-platform applications simpler.
7) Should Vulkan define a common external handle type and provide Vulkan functions to facilitate cross-process sharing of such handles rather than relying on native handles to define the external objects?
RESOLVED: No. Cross-process sharing of resources is best left to native platforms. There are myriad security and extensibility issues with such a mechanism, and attempting to re-solve all those issues within Vulkan does not align with Vulkan’s purpose as a graphics API. If desired, such a mechanism could be built as a layer or helper library on top of the opaque native handle defined in this family of extensions.
8) Must implementations provide additional guarantees about state implicitly included in memory objects for those memory objects that may be exported?
RESOLVED: Implementations must ensure that sharing memory objects does not transfer any information between the exporting and importing instances and APIs other than that required to share the data contained in the memory objects explicitly shared. As specific examples, data from previously freed memory objects that used the same underlying physical memory, and data from memory obects using adjacent physical memory must not be visible to applications importing an exported memory object.
9) Must implementations validate external handles the application provides as input to memory import operations?
RESOLVED: Implementations must return an error to the application if the provided memory handle cannot be used to complete the requested import operation. However, implementations need not validate handles are of the exact type specified by the application.
VK_KHR_external_memory_capabilities
- Name String
-
VK_KHR_external_memory_capabilities - Extension Type
-
Instance extension
- Registered Extension Number
-
72
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2016-10-17
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Interacts with
VK_KHR_dedicated_allocation. -
Interacts with
VK_NV_dedicated_allocation. -
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Ian Elliot, Google
-
Jesse Hall, Google
-
James Jones, NVIDIA
-
An application may wish to reference device memory in multiple Vulkan logical devices or instances, in multiple processes, and/or in multiple APIs. This extension provides a set of capability queries and handle definitions that allow an application to determine what types of “external” memory handles an implementation supports for a given set of use cases.
New Object Types
None.
New Enum Constants
-
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_IMAGE_FORMAT_INFO_KHR -
VK_STRUCTURE_TYPE_EXTERNAL_IMAGE_FORMAT_PROPERTIES_KHR -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_BUFFER_INFO_KHR -
VK_STRUCTURE_TYPE_EXTERNAL_BUFFER_PROPERTIES_KHR -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ID_PROPERTIES_KHR -
VK_LUID_SIZE_KHR
New Structs
New Functions
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Issues
1) Why do so many external memory capabilities need to be queried on a per-memory-handle-type basis?
PROPOSED RESOLUTION: This is because some handle types are based on OS-native objects that have far more limited capabilities than the very generic Vulkan memory objects. Not all memory handle types can name memory objects that support 3D images, for example. Some handle types cannot even support the deferred image and memory binding behavior of Vulkan and require specifying the image when allocating or importing the memory object.
2) Do the VkExternalImageFormatPropertiesKHR and VkExternalBufferPropertiesKHR structs need to include a list of memory type bits that support the given handle type?
PROPOSED RESOLUTION: No. The memory types that don’t support the handle types will simply be filtered out of the results returned by vkGetImageMemoryRequirements and vkGetBufferMemoryRequirements when a set of handle types was specified at image or buffer creation time.
3) Should the non-opaque handle types be moved to their own extension?
PROPOSED RESOLUTION: Perhaps. However, defining the handle type bits does very little and does not require any platform-specific types on its own, and it’s easier to maintain the bitfield values in a single extension for now. Presumably more handle types could be added by separate extensions though, and it would be midly weird to have some platform-specific ones defined in the core spec and some in extensions
4) Do we need a D3D11_TILEPOOL type?
PROPOSED RESOLUTION: No. This is technically possible, but the synchronization is awkward. D3D11 surfaces must be synchronized using shared mutexes, and these synchronization primitives are shared by the entire memory object, so D3D11 shared allocations divided among multiple buffer and image bindings may be difficult to synchronize.
5) Should the Windows 7-compatible handle types be named “KMT” handles or “GLOBAL_SHARE” handles?
PROPOSED RESOLUTION: KMT, simply because it is more concise.
6) How do applications identify compatible devices and drivers across instance, process, and API boundaries when sharing memory?
PROPOSED RESOLUTION: New device properties are exposed that allow applications to correctly correlate devices and drivers. A device and driver UUID that must both match to ensure sharing compatibility between two Vulkan instances, or a Vulkan instance and an extensible external API are added. To allow correlating with Direct3D devices, a device LUID is added that corresponds to a DXGI adapter LUID. A driver ID is not needed for Direct3D because mismatched driver component versions are not a currently supported configuration on the Windows OS. Should support for such configurations be introduced at the OS level, further Vulkan extensions would be needed to correlate userspace component builds.
VK_KHR_external_memory_fd
- Name String
-
VK_KHR_external_memory_fd - Extension Type
-
Device extension
- Registered Extension Number
-
75
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_external_memory
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2016-10-21
- IP Status
-
No known IP claims.
- Contributors
-
-
James Jones, NVIDIA
-
Jeff Juliano, NVIDIA
-
An application may wish to reference device memory in multiple Vulkan logical devices or instances, in multiple processes, and/or in multiple APIs. This extension enables an application to export POSIX file descriptor handles from Vulkan memory objects and to import Vulkan memory objects from POSIX file descriptor handles exported from other Vulkan memory objects or from similar resources in other APIs.
New Object Types
None.
New Enum Constants
-
VK_STRUCTURE_TYPE_IMPORT_MEMORY_FD_INFO_KHR -
VK_STRUCTURE_TYPE_MEMORY_FD_PROPERTIES_KHR -
VK_STRUCTURE_TYPE_MEMORY_GET_FD_INFO_KHR
New Enums
None.
New Functions
Issues
1) Does the application need to close the file descriptor returned by vkGetMemoryFdKHR?
RESOLVED: Yes, unless it is passed back in to a driver instance to import the memory. A successful get call transfers ownership of the file descriptor to the application, and a successful import transfers it back to the driver. Destroying the original memory object will not close the file descriptor or remove its reference to the underlying memory resource associated with it.
2) Do drivers ever need to expose multiple file descriptors per memory object?
RESOLVED: No. This would indicate there are actually multiple memory objects, rather than a single memory object.
3) How should the valid size and memory type for POSIX file descriptor memory handles created outside of Vulkan be specified?
RESOLVED: The valid memory types are queried directly from the external handle. The size will be specified by future extensions that introduce such external memory handle types.
VK_KHR_external_memory_win32
- Name String
-
VK_KHR_external_memory_win32 - Extension Type
-
Device extension
- Registered Extension Number
-
74
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_external_memory
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2016-10-21
- IP Status
-
No known IP claims.
- Contributors
-
-
James Jones, NVIDIA
-
Jeff Juliano, NVIDIA
-
Carsten Rohde, NVIDIA
-
An application may wish to reference device memory in multiple Vulkan logical devices or instances, in multiple processes, and/or in multiple APIs. This extension enables an application to export Windows handles from Vulkan memory objects and to import Vulkan memory objects from Windows handles exported from other Vulkan memory objects or from similar resources in other APIs.
New Object Types
None.
New Enum Constants
-
VK_STRUCTURE_TYPE_IMPORT_MEMORY_WIN32_HANDLE_INFO_KHR -
VK_STRUCTURE_TYPE_EXPORT_MEMORY_WIN32_HANDLE_INFO_KHR -
VK_STRUCTURE_TYPE_MEMORY_WIN32_HANDLE_PROPERTIES_KHR -
VK_STRUCTURE_TYPE_MEMORY_GET_WIN32_HANDLE_INFO_KHR
New Enums
None.
New Structs
New Functions
Issues
1) Do applications need to call CloseHandle() on the values returned
from vkGetMemoryWin32HandleKHR when handleType is
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_KHR?
|
editing-note
(Jon) This issue refers to a token from
|
RESOLVED: Yes, unless it is passed back in to another driver instance to import the object. A successful get call transfers ownership of the handle to the application. Destroying the memory object will not destroy the handle or the handle’s reference to the underlying memory resource.
2) Should the language regarding KMT/Windows 7 handles be moved to a separate extension so that it can be deprecated over time?
RESOLVED: No. Support for them can be deprecated by drivers if they choose, by no longer returning them in the supported handle types of the instance level queries.
3) How should the valid size and memory type for windows memory handles created outside of Vulkan be specified?
RESOLVED: The valid memory types are queried directly from the external handle. The size is determined by the associated image or buffer memory requirements for external handle types that require dedicated allocations, and by the size specified when creating the object from which the handle was exported for other external handle types.
VK_KHR_external_semaphore
- Name String
-
VK_KHR_external_semaphore - Extension Type
-
Device extension
- Registered Extension Number
-
78
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2016-10-21
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Jason Ekstrand, Intel
-
Jesse Hall, Google
-
Tobias Hector, Imagination Technologies
-
James Jones, NVIDIA
-
Jeff Juliano, NVIDIA
-
Matthew Netsch, Qualcomm Technologies, Inc.
-
Ray Smith, ARM
-
Chad Versace, Google
-
An application using external memory may wish to synchronize access to that memory using semaphores. This extension enables an application to create semaphores from which non-Vulkan handles that reference the underlying synchronization primitive can be exported.
New Object Types
None.
New Enum Constants
-
VK_STRUCTURE_TYPE_EXPORT_SEMAPHORE_CREATE_INFO_KHR -
VK_ERROR_INVALID_EXTERNAL_HANDLE_KHR
New Enums
New Structs
New Functions
None.
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Issues
1) Should there be restrictions on what side effects can occur when waiting on imported semaphores that are in an invalid state?
RESOLVED: Yes. Normally, validating such state would be the responsibility of the application, and the implementation would be free to enter an undefined state if valid usage rules were violated. However, this could cause security concerns when using imported semaphores, as it would require the importing application to trust the exporting application to ensure the state is valid. Requiring this level of trust is undesireable for many potential use cases.
2) Must implementations validate external handles the application provides as input to semaphore state import operations?
RESOLVED: Implementations must return an error to the application if the provided semaphore state handle cannot be used to complete the requested import operation. However, implementations need not validate handles are of the exact type specified by the application.
VK_KHR_external_semaphore_capabilities
- Name String
-
VK_KHR_external_semaphore_capabilities - Extension Type
-
Instance extension
- Registered Extension Number
-
77
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2016-10-20
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Jesse Hall, Google
-
James Jones, NVIDIA
-
Jeff Juliano, NVIDIA
-
An application may wish to reference device semaphores in multiple Vulkan logical devices or instances, in multiple processes, and/or in multiple APIs. This extension provides a set of capability queries and handle definitions that allow an application to determine what types of “external” semaphore handles an implementation supports for a given set of use cases.
New Object Types
None.
New Enum Constants
-
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_SEMAPHORE_INFO_KHR -
VK_STRUCTURE_TYPE_EXTERNAL_SEMAPHORE_PROPERTIES_KHR -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ID_PROPERTIES_KHR -
VK_LUID_SIZE_KHR
New Structs
New Functions
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Issues
VK_KHR_external_semaphore_fd
- Name String
-
VK_KHR_external_semaphore_fd - Extension Type
-
Device extension
- Registered Extension Number
-
80
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_external_semaphore
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2016-10-21
- IP Status
-
No known IP claims.
- Contributors
-
-
Jesse Hall, Google
-
James Jones, NVIDIA
-
Jeff Juliano, NVIDIA
-
Carsten Rohde, NVIDIA
-
An application using external memory may wish to synchronize access to that memory using semaphores. This extension enables an application to export semaphore payload to and import semaphore payload from POSIX file descriptors.
New Object Types
None.
New Enum Constants
-
VK_STRUCTURE_TYPE_IMPORT_SEMAPHORE_FD_INFO_KHR -
VK_STRUCTURE_TYPE_SEMAPHORE_GET_FD_INFO_KHR
New Enums
None.
New Structs
New Functions
Issues
1) Does the application need to close the file descriptor returned by vkGetSemaphoreFdKHR?
RESOLVED: Yes, unless it is passed back in to a driver instance to import the semaphore. A successful get call transfers ownership of the file descriptor to the application, and a successful import transfers it back to the driver. Destroying the original semaphore object will not close the file descriptor or remove its reference to the underlying semaphore resource associated with it.
VK_KHR_external_semaphore_win32
- Name String
-
VK_KHR_external_semaphore_win32 - Extension Type
-
Device extension
- Registered Extension Number
-
79
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_external_semaphore
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2016-10-21
- IP Status
-
No known IP claims.
- Contributors
-
-
James Jones, NVIDIA
-
Jeff Juliano, NVIDIA
-
Carsten Rohde, NVIDIA
-
An application using external memory may wish to synchronize access to that memory using semaphores. This extension enables an application to export semaphore payload to and import semaphore payload from Windows handles.
New Object Types
None.
New Enum Constants
-
VK_STRUCTURE_TYPE_IMPORT_SEMAPHORE_WIN32_HANDLE_INFO_KHR -
VK_STRUCTURE_TYPE_EXPORT_SEMAPHORE_WIN32_HANDLE_INFO_KHR -
VK_STRUCTURE_TYPE_D3D12_FENCE_SUBMIT_INFO_KHR -
VK_STRUCTURE_TYPE_SEMAPHORE_GET_WIN32_HANDLE_INFO_KHR
New Enums
None.
New Structs
New Functions
Issues
1) Do applications need to call CloseHandle() on the values returned
from vkGetSemaphoreWin32HandleKHR when handleType is
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT_KHR?
RESOLVED: Yes, unless it is passed back in to another driver instance to import the object. A successful get call transfers ownership of the handle to the application. Destroying the semaphore object will not destroy the handle or the handle’s reference to the underlying semaphore resource.
2) Should the language regarding KMT/Windows 7 handles be moved to a separate extension so that it can be deprecated over time?
RESOLVED: No. Support for them can be deprecated by drivers if they choose, by no longer returning them in the supported handle types of the instance level queries.
3) Should applications be allowed to specify additional object attributes for shared handles?
RESOLVED: Yes. Applications will be allowed to provide similar attributes to those they would to any other handle creation API.
4) How do applications communicate the desired fence values to use with
D3D12_FENCE-based Vulkan semaphores?
RESOLVED: There are a couple of options. The values for the signaled and reset states could be communicated up front when creating the object and remain static for the life of the Vulkan semaphore, or they could be specified using auxiliary structures when submitting semaphore signal and wait operations, similar to what is done with the keyed mutex extensions. The latter is more flexible and consistent with the keyed mutex usage, but the former is a much simpler API.
Since Vulkan tends to favor flexibility and consistency over simplicity, a new structure specifying D3D12 fence acquire and release values is added to the vkQueueSubmit function.
VK_KHR_get_display_properties2
- Name String
-
VK_KHR_get_display_properties2 - Extension Type
-
Instance extension
- Registered Extension Number
-
122
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_display
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2017-02-21
- IP Status
-
No known IP claims.
- Contributors
-
-
Ian Elliott, Google
-
James Jones, NVIDIA
-
This extension provides new entry points to query device display properties and capabilities in a way that can be easily extended by other extensions, without introducing any further entry points. This extension can be considered the VK_KHR_display equivalent of the VK_KHR_get_physical_device_properties2 extension.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_DISPLAY_PROPERTIES_2_KHR -
VK_STRUCTURE_TYPE_DISPLAY_PLANE_PROPERTIES_2_KHR -
VK_STRUCTURE_TYPE_DISPLAY_MODE_PROPERTIES_2_KHR -
VK_STRUCTURE_TYPE_DISPLAY_PLANE_INFO_2_KHR -
VK_STRUCTURE_TYPE_DISPLAY_PLANE_CAPABILITIES_2_KHR
-
New Enums
None.
New Structures
New Functions
Issues
1) What should this extension be named?
RESOLVED: VK_KHR_get_display_properties2. Other alternatives:
-
VK_KHR_display2
-
One extension, combined with VK_KHR_surface_capabilites2.
2) Should extensible input structs be added for these new functions:
RESOLVED:
-
vkGetPhysicalDeviceDisplayProperties2KHR: No. The only current input is a VkPhysicalDevice. Other inputs wouldn’t make sense.
-
vkGetPhysicalDeviceDisplayPlaneProperties2KHR: No. The only current input is a VkPhysicalDevice. Other inputs wouldn’t make sense.
-
vkGetDisplayModeProperties2KHR: No. The only curent inputs are a VkPhysicalDevice and a VkDisplayModeKHR. Other inputs wouldn’t make sense.
3) Should additional display query functions be extended?
RESOLVED:
-
vkGetDisplayPlaneSupportedDisplaysKHR: No. Extensions should instead extend vkGetDisplayPlaneCapabilitiesKHR().
Version History
-
Revision 1, 2017-02-21 (James Jones)
-
Initial draft.
-
VK_KHR_get_memory_requirements2
- Name String
-
VK_KHR_get_memory_requirements2 - Extension Type
-
Device extension
- Registered Extension Number
-
147
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Jason Ekstrand @jekstrand
-
- Last Modified Date
-
2017-09-05
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Jason Ekstrand, Intel
-
Jeff Bolz, NVIDIA
-
Jesse Hall, Google
-
This extension provides new entry points to query memory requirements of
images and buffers in a way that can be easily extended by other extensions,
without introducing any further entry points.
The Vulkan 1.0 VkMemoryRequirements and
VkSparseImageMemoryRequirements structures do not include a
sType/pNext, this extension wraps them in new structures with
sType/pNext so an application can query a chain of memory
requirements structures by constructing the chain and letting the
implementation fill them in.
A new command is added for each vkGet*MemoryRequrements command in
core Vulkan 1.0.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_BUFFER_MEMORY_REQUIREMENTS_INFO_2_KHR -
VK_STRUCTURE_TYPE_IMAGE_MEMORY_REQUIREMENTS_INFO_2_KHR -
VK_STRUCTURE_TYPE_IMAGE_SPARSE_MEMORY_REQUIREMENTS_INFO_2_KHR -
VK_STRUCTURE_TYPE_MEMORY_REQUIREMENTS_2_KHR -
VK_STRUCTURE_TYPE_SPARSE_IMAGE_MEMORY_REQUIREMENTS_2_KHR
-
New Enums
None.
New Structures
New Functions
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Issues
None.
Version History
-
Revision 1, 2017-03-23 (Jason Ekstrand)
-
Internal revisions
-
VK_KHR_get_physical_device_properties2
- Name String
-
VK_KHR_get_physical_device_properties2 - Extension Type
-
Instance extension
- Registered Extension Number
-
60
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Jeff Bolz @jeffbolznv
-
- Last Modified Date
-
2017-09-05
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Jeff Bolz, NVIDIA
-
Ian Elliott, Google
-
This extension provides new entry points to query device features, device
properties, and format properties in a way that can be easily extended by
other extensions, without introducing any further entry points.
The Vulkan 1.0 feature/limit/formatproperty structures do not include
sType/pNext members.
This extension wraps them in new structures with sType/pNext
members, so an application can query a chain of feature/limit/formatproperty
structures by constructing the chain and letting the implementation fill
them in.
A new command is added for each vkGetPhysicalDevice* command in core
Vulkan 1.0.
The new feature structure (and a chain of extension structures) can also be
passed in to device creation to enable features.
This extension also allows applications to use the physical-device components of device extensions before vkCreateDevice is called.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FEATURES_2_KHR -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2_KHR -
VK_STRUCTURE_TYPE_FORMAT_PROPERTIES_2_KHR -
VK_STRUCTURE_TYPE_IMAGE_FORMAT_PROPERTIES_2_KHR -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_FORMAT_INFO_2_KHR -
VK_STRUCTURE_TYPE_QUEUE_FAMILY_PROPERTIES_2_KHR -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PROPERTIES_2_KHR -
VK_STRUCTURE_TYPE_SPARSE_IMAGE_FORMAT_PROPERTIES_2_KHR -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SPARSE_IMAGE_FORMAT_INFO_2_KHR
-
New Enums
None.
New Structures
New Functions
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Issues
None.
Examples
// Get features with a hypothetical future extension.
VkHypotheticalExtensionFeaturesKHR hypotheticalFeatures =
{
VK_STRUCTURE_TYPE_HYPOTHETICAL_FEATURES_KHR, // sType
NULL, // pNext
};
VkPhysicalDeviceFeatures2KHR features =
{
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FEATURES_2_KHR, // sType
&hypotheticalFeatures, // pNext
};
// After this call, features and hypotheticalFeatures have been filled out.
vkGetPhysicalDeviceFeatures2KHR(physicalDevice, &features);
// Properties/limits can be chained and queried similarly.
// Enable some features:
VkHypotheticalExtensionFeaturesKHR enabledHypotheticalFeatures =
{
VK_STRUCTURE_TYPE_HYPOTHETICAL_FEATURES_KHR, // sType
NULL, // pNext
};
VkPhysicalDeviceFeatures2KHR enabledFeatures =
{
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FEATURES_2_KHR, // sType
&enabledHypotheticalFeatures, // pNext
};
enabledFeatures.features.xyz = VK_TRUE;
enabledHypotheticalFeatures.abc = VK_TRUE;
VkDeviceCreateInfo deviceCreateInfo =
{
VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO, // sType
&enabledFeatures, // pNext
...
NULL, // pEnabledFeatures
}
VkDevice device;
vkCreateDevice(physicalDevice, &deviceCreateInfo, NULL, &device);
Version History
-
Revision 1, 2016-09-12 (Jeff Bolz)
-
Internal revisions
-
-
Revision 2, 2016-11-02 (Ian Elliott)
-
Added ability for applications to use the physical-device components of device extensions before vkCreateDevice is called.
-
VK_KHR_get_surface_capabilities2
- Name String
-
VK_KHR_get_surface_capabilities2 - Extension Type
-
Instance extension
- Registered Extension Number
-
120
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_surface
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2017-02-27
- IP Status
-
No known IP claims.
- Contributors
-
-
Ian Elliott, Google
-
James Jones, NVIDIA
-
Alon Or-bach, Samsung
-
This extension provides new entry points to query device surface
capabilities in a way that can be easily extended by other extensions,
without introducing any further entry points.
This extension can be considered the VK_KHR_surface equivalent of the
VK_KHR_get_physical_device_properties2 extension.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SURFACE_INFO_2_KHR -
VK_STRUCTURE_TYPE_SURFACE_CAPABILITIES_2_KHR -
VK_STRUCTURE_TYPE_SURFACE_FORMAT_2_KHR
-
New Enums
None.
Issues
1) What should this extension be named?
RESOLVED: VK_KHR_get_surface_capabilities2.
Other alternatives:
-
VK_KHR_surface2 -
One extension, combining a separate display-specific query extension.
2) Should additional WSI query functions be extended?
RESOLVED:
-
vkGetPhysicalDeviceSurfaceCapabilitiesKHR: Yes. The need for this motivated the extension.
-
vkGetPhysicalDeviceSurfaceSupportKHR: No. Currently only has boolean output. Extensions should instead extend vkGetPhysicalDeviceSurfaceCapabilities2KHR.
-
vkGetPhysicalDeviceSurfacePresentModesKHR: No. Recent discussion concluded this introduced too much variability for applications to deal with. Extensions should instead extend vkGetPhysicalDeviceSurfaceCapabilities2KHR.
-
vkGetPhysicalDeviceXlibPresentationSupportKHR: Not in this extension.
-
vkGetPhysicalDeviceXcbPresentationSupportKHR: Not in this extension.
-
vkGetPhysicalDeviceWaylandPresentationSupportKHR: Not in this extension.
-
vkGetPhysicalDeviceMirPresentationSupportKHR: Not in this extension.
-
vkGetPhysicalDeviceWin32PresentationSupportKHR: Not in this extension.
Version History
-
Revision 1, 2017-02-27 (James Jones)
-
Initial draft.
-
VK_KHR_image_format_list
- Name String
-
VK_KHR_image_format_list - Extension Type
-
Device extension
- Registered Extension Number
-
148
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Jason Ekstrand @jekstrand
-
- Last Modified Date
-
2017-03-20
- IP Status
-
No known IP claims.
- Contributors
-
-
Jason Ekstrand, Intel
-
Jan-Harald Fredriksen, ARM
-
Jeff Bolz, NVIDIA
-
Jeff Leger, Qualcomm
-
Neil Henning, Codeplay
-
On some implementations, setting the
VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT on image creation can cause access
to that image to perform worse than an equivalent image created without
VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT because the implementation does not
know what view formats will be paired with the image.
This extension allows an application to provide the list of all formats that can be used with an image when it is created. The implementation may then be able to create a more efficient image that supports the subset of formats required by the application without having to support all formats in the format compatibility class of the image format.
New Object Types
None.
New Enum Constants
-
VK_STRUCTURE_TYPE_IMAGE_FORMAT_LIST_CREATE_INFO_KHR
New Enums
None.
New Structs
New Functions
None.
Issues
VK_KHR_incremental_present
- Name String
-
VK_KHR_incremental_present - Extension Type
-
Device extension
- Registered Extension Number
-
85
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_swapchain
-
- Contact
-
-
Ian Elliott @ianelliottus
-
- Last Modified Date
-
2016-11-02
- IP Status
-
No known IP claims.
- Contributors
-
-
Ian Elliott, Google
-
Jesse Hall, Google
-
Alon Or-bach, Samsung
-
James Jones, NVIDIA
-
Daniel Rakos, AMD
-
Ray Smith, ARM
-
Mika Isojarvi, Google
-
Jeff Juliano, NVIDIA
-
Jeff Bolz, NVIDIA
-
This device extension extends vkQueuePresentKHR, from the
VK_KHR_swapchain extension, allowing an application to specify a list
of rectangular, modified regions of each image to present.
This should be used in situations where an application is only changing a
small portion of the presentable images within a swapchain, since it enables
the presentation engine to avoid wasting time presenting parts of the
surface that haven’t changed.
This extension is leveraged from the EGL_KHR_swap_buffers_with_damage extension.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PRESENT_REGIONS_KHR
-
New Enums
None.
New Structures
New Functions
None.
Examples
None.
Issues
1) How should we handle steroescopic-3D swapchains? We need to add a layer
for each rectangle.
One approach is to create another struct that contains the VkRect2D
plus layer, and have VkPresentRegionsKHR point to an array of that
struct.
Another approach is to have two parallel arrays, pRectangles and
pLayers, where pRectangles[i] and pLayers[i] must be used
together.
Which approach should we use, and if the array of a new structure, what
should that be called?
RESOLVED: Create a new structure, which is a VkRect2D plus a layer, and will be called VkRectLayerKHR.
2) Where is the origin of the VkRectLayerKHR?
RESOLVED: The upper left corner of the presentable image(s) of the swapchain, per the definition of framebuffer coordinates.
3) Does the rectangular region, VkRectLayerKHR, specify pixels of the swapchain’s image(s), or of the surface?
RESOLVED: Of the image(s). Some presentation engines may scale the pixels of a swapchain’s image(s) to the size of the surface. The size of the swapchain’s image(s) will be consistent, where the size of the surface may vary over time.
4) What if all of the rectangles for a given swapchain contain a width and/or height of zero?
RESOLVED: The application is indicating that no pixels changed since the last present. The presentation engine may use such a hint and not update any pixels for the swapchain. However, all other semantics of vkQueuePresentKHR must still be honored, including waiting for semaphores to signal.
Version History
-
Revision 1, 2016-11-02 (Ian Elliott)
-
Internal revisions
-
VK_KHR_maintenance1
- Name String
-
VK_KHR_maintenance1 - Extension Type
-
Device extension
- Registered Extension Number
-
70
- Revision
-
2
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Piers Daniell @pdaniell-nv
-
- Last Modified Date
-
2018-03-13
- Interactions and External Dependencies
-
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Dan Ginsburg, Valve
-
Daniel Koch, NVIDIA
-
Daniel Rakos, AMD
-
Jan-Harald Fredriksen, ARM
-
Jason Ekstrand, Intel
-
Jeff Bolz, NVIDIA
-
Jesse Hall, Google
-
John Kessenich, Google
-
Michael Worcester, Imagination Technologies
-
Neil Henning, Codeplay Software Ltd.
-
Piers Daniell, NVIDIA
-
Slawomir Grajewski, Intel
-
Tobias Hector, Imagination Technologies
-
Tom Olson, ARM
-
VK_KHR_maintenance1 adds a collection of minor features that were
intentionally left out or overlooked from the original Vulkan 1.0 release.
The new features are as follows:
-
Allow 2D and 2D array image views to be created from 3D images, which can then be used as color framebuffer attachments. This allows applications to render to slices of a 3D image.
-
Support vkCmdCopyImage between 2D array layers and 3D slices. This extension allows copying from layers of a 2D array image to slices of a 3D image and vice versa.
-
Allow negative height to be specified in the VkViewport::
heightfield to perform y-inversion of the clip-space to framebuffer-space transform. This allows apps to avoid having to usegl_Position.y = -gl_Position.yin shaders also targeting other APIs. -
Allow implementations to express support for doing just transfers and clears of image formats that they otherwise support no other format features for. This is done by adding new format feature flags
VK_FORMAT_FEATURE_TRANSFER_SRC_BIT_KHRandVK_FORMAT_FEATURE_TRANSFER_DST_BIT_KHR. -
Support vkCmdFillBuffer on transfer-only queues. Previously vkCmdFillBuffer was defined to only work on command buffers allocated from command pools which support graphics or compute queues. It is now allowed on queues that just support transfer operations.
-
Fix the inconsistency of how error conditions are returned between the vkCreateGraphicsPipelines and vkCreateComputePipelines functions and the vkAllocateDescriptorSets and vkAllocateCommandBuffers functions.
-
Add new
VK_ERROR_OUT_OF_POOL_MEMORY_KHRerror so implementations can give a more precise reason for vkAllocateDescriptorSets failures. -
Add a new command vkTrimCommandPoolKHR which gives the implementation an opportunity to release any unused command pool memory back to the system.
New Object Types
None.
New Enum Constants
-
VK_ERROR_OUT_OF_POOL_MEMORY_KHR -
VK_FORMAT_FEATURE_TRANSFER_SRC_BIT_KHR -
VK_FORMAT_FEATURE_TRANSFER_DST_BIT_KHR -
VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT_KHR
New Enums
None.
New Structures
None.
New Functions
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Issues
-
Are viewports with zero height allowed?
RESOLVED: Yes, although they have low utility.
Version History
-
Revision 1, 2016-10-26 (Piers Daniell)
-
Internal revisions
-
-
Revision 2, 2018-03-13 (Jon Leech)
-
Add issue for zero-height viewports
-
VK_KHR_maintenance2
- Name String
-
VK_KHR_maintenance2 - Extension Type
-
Device extension
- Registered Extension Number
-
118
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Michael Worcester @michaelworcester
-
- Last Modified Date
-
2017-09-05
- Interactions and External Dependencies
-
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Michael Worcester, Imagination Technologies
-
Stuart Smith, Imagination Technologies
-
Jeff Bolz, NVIDIA
-
Daniel Koch, NVIDIA
-
Jan-Harald Fredriksen, ARM
-
Daniel Rakos, AMD
-
Neil Henning, Codeplay
-
Piers Daniell, NVIDIA
-
VK_KHR_maintenance2 adds a collection of minor features that were
intentionally left out or overlooked from the original Vulkan 1.0 release.
The new features are as follows:
-
Allow the application to specify which aspect of an input attachment might be read for a given subpass.
-
Allow implementations to express the clipping behavior of points.
-
Allow creating images with usage flags that may not be supported for the base image’s format, but are supported for image views of the image that have a different but compatible format.
-
Allow creating uncompressed image views of compressed images.
-
Allow the application to select between an upper-left and lower-left origin for the tessellation domain space.
-
Adds two new image layouts for depth stencil images to allow either the depth or stencil aspect to be read-only while the other aspect is writable.
Input Attachment Specification
Input attachment specification allows an application to specify which aspect
of a multi-aspect image (e.g. a combined depth stencil format) will be
accessed via a subpassLoad operation.
On some implementations there may be a performance penalty if the implementation does not know (at vkCreateRenderPass time) which aspect(s) of multi-aspect images can be be accessed as input attachments.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_RENDER_PASS_INPUT_ATTACHMENT_ASPECT_CREATE_INFO_KHR -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_POINT_CLIPPING_PROPERTIES_KHR -
VK_STRUCTURE_TYPE_IMAGE_VIEW_USAGE_CREATE_INFO_KHR -
VK_STRUCTURE_TYPE_PIPELINE_TESSELLATION_DOMAIN_ORIGIN_STATE_CREATE_INFO_KHR
-
-
Extending VkImageCreateFlagBits:
-
VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT_KHR -
VK_IMAGE_CREATE_EXTENDED_USAGE_BIT_KHR
-
-
Extending VkImageLayout
-
VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL_KHR -
VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL_KHR
-
-
VK_POINT_CLIPPING_BEHAVIOR_ALL_CLIP_PLANES_KHR -
VK_POINT_CLIPPING_BEHAVIOR_USER_CLIP_PLANES_ONLY_KHR
New Structures
New Functions
None.
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Input Attachment Specification Example
Consider the case where a render pass has two subpasses and two attachments.
Attachment 0 has the format VK_FORMAT_D24_UNORM_S8_UINT, attachment 1
has some color format.
Subpass 0 writes to attachment 0, subpass 1 reads only the depth information from attachment 0 (using inputAttachmentRead) and writes to attachment 1.
VkInputAttachmentAspectReferenceKHR references[] = {
{
.subpass = 1,
.inputAttachmentIndex = 0,
.aspectMask = VK_IMAGE_ASPECT_DEPTH_BIT
}
};
VkRenderPassInputAttachmentAspectCreateInfoKHR specifyAspects = {
.sType = VK_STRUCTURE_TYPE_RENDER_PASS_INPUT_ATTACHMENT_ASPECT_CREATE_INFO_KHR,
.pNext = NULL,
.aspectReferenceCount = 1,
.pAspectReferences = references
};
VkRenderPassCreateInfo createInfo = {
...
.pNext = &specifyAspects,
...
}
vkCreateRenderPass(...);
Issues
1) What is the default tessellation domain origin?
RESOLVED: Vulkan 1.0 originally inadvertently documented a lower-left origin, but the conformance tests and all implementations implemented an upper-left origin. This extension adds a control to select between lower-left (for compatibility with OpenGL) and upper-left, and we retroactively fix unextended Vulkan to have a default of an upper-left origin.
Version History
-
Revision 1, 2017-04-28
VK_KHR_maintenance3
- Name String
-
VK_KHR_maintenance3 - Extension Type
-
Device extension
- Registered Extension Number
-
169
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Jeff Bolz @jeffbolznv
-
- Status
-
Draft
- Last Modified Date
-
2017-09-05
- Interactions and External Dependencies
-
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Jeff Bolz, NVIDIA
-
VK_KHR_maintenance3 adds a collection of minor features that were
intentionally left out or overlooked from the original Vulkan 1.0 release.
The new features are as follows:
-
A limit on the maximum number of descriptors that are supported in a single descriptor set layout. Some implementations have a limit on the total size of descriptors in a set, which can’t be expressed in terms of the limits in Vulkan 1.0.
-
A limit on the maximum size of a single memory allocation. Some platforms have kernel interfaces that limit the maximum size of an allocation.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MAINTENANCE_3_PROPERTIES_KHR -
VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_SUPPORT_KHR
-
New Enums
None.
New Functions
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Issues
None.
Version History
-
Revision 1, 2017-08-22
VK_KHR_mir_surface
- Name String
-
VK_KHR_mir_surface - Extension Type
-
Instance extension
- Registered Extension Number
-
8
- Revision
-
4
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_surface
-
- Contact
-
-
Jesse Hall @critsec,Ian Elliott @ianelliottus
-
- Last Modified Date
-
2015-11-28
- IP Status
-
No known IP claims.
- Contributors
-
-
Patrick Doane, Blizzard
-
Jason Ekstrand, Intel
-
Ian Elliott, LunarG
-
Courtney Goeltzenleuchter, LunarG
-
Jesse Hall, Google
-
James Jones, NVIDIA
-
Antoine Labour, Google
-
Jon Leech, Khronos
-
David Mao, AMD
-
Norbert Nopper, Freescale
-
Alon Or-bach, Samsung
-
Daniel Rakos, AMD
-
Graham Sellers, AMD
-
Ray Smith, ARM
-
Jeff Vigil, Qualcomm
-
Chia-I Wu, LunarG
-
The VK_KHR_mir_surface extension is an instance extension.
It provides a mechanism to create a VkSurfaceKHR object (defined by
the VK_KHR_surface extension) that refers to a Mir surface, as well as
a query to determine support for rendering to the windows desktop.
New Object Types
None
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_MIR_SURFACE_CREATE_INFO_KHR
-
New Enums
None
New Structures
Issues
1) Does Mir need a way to query for compatibility between a particular physical device (and queue family?) and a specific Mir connection, screen, window, etc.?
RESOLVED: Yes, vkGetPhysicalDeviceMirPresentationSupportKHR was added to address this.
Version History
-
Revision 1, 2015-09-23 (Jesse Hall)
-
Initial draft, based on the previous contents of VK_EXT_KHR_swapchain (later renamed VK_EXT_KHR_surface).
-
-
Revision 2, 2015-10-02 (James Jones)
-
Added vkGetPhysicalDeviceMirPresentationSupportKHR to resolve issue #1.
-
-
Revision 3, 2015-10-26 (Ian Elliott)
-
Renamed from VK_EXT_KHR_mir_surface to VK_KHR_mir_surface.
-
-
Revision 4, 2015-11-28 (Daniel Rakos)
-
Updated the surface create function to take a pCreateInfo structure.
-
VK_KHR_multiview
- Name String
-
VK_KHR_multiview - Extension Type
-
Device extension
- Registered Extension Number
-
54
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Jeff Bolz @jeffbolznv
-
- Last Modified Date
-
2016-10-28
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Jeff Bolz, NVIDIA
-
This extension has the same goal as the OpenGL ES GL_OVR_multiview extension - it enables rendering to multiple “views” by recording a single set of commands to be executed with slightly different behavior for each view. It includes a concise way to declare a render pass with multiple views, and gives implementations freedom to render the views in the most efficient way possible.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_RENDER_PASS_MULTIVIEW_CREATE_INFO_KHR -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_FEATURES_KHR -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PROPERTIES_KHR
-
-
Extending VkDependencyFlagBits
-
VK_DEPENDENCY_VIEW_LOCAL_BIT_KHR
-
New Enums
None.
New Structures
New Functions
None.
New Built-In Variables
New SPIR-V Capabilities
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Issues
None.
Examples
None.
Version History
-
Revision 1, 2016-10-28 (Jeff Bolz)
-
Internal revisions
-
VK_KHR_push_descriptor
- Name String
-
VK_KHR_push_descriptor - Extension Type
-
Device extension
- Registered Extension Number
-
81
- Revision
-
2
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Jeff Bolz @jeffbolznv
-
- Last Modified Date
-
2017-09-12
- IP Status
-
No known IP claims.
- Contributors
-
-
Jeff Bolz, NVIDIA
-
Michael Worcester, Imagination Technologies
-
This extension allows descriptors to be written into the command buffer, while the implementation is responsible for managing their memory. Push descriptors may enable easier porting from older APIs and in some cases can be more efficient than writing descriptors into descriptor sets.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PUSH_DESCRIPTOR_PROPERTIES_KHR
-
-
Extending VkDescriptorSetLayoutCreateFlagBits
-
VK_DESCRIPTOR_SET_LAYOUT_CREATE_PUSH_DESCRIPTOR_BIT_KHR
-
-
Extending VkDescriptorUpdateTemplateType
-
VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHR=== New Enums
-
None.
New Structures
Issues
None.
Examples
None.
Version History
-
Revision 1, 2016-10-15 (Jeff Bolz)
-
Internal revisions
-
-
Revision 2, 2017-09-12 (Tobias Hector)
-
Added interactions with Vulkan 1.1
-
VK_KHR_relaxed_block_layout
- Name String
-
VK_KHR_relaxed_block_layout - Extension Type
-
Device extension
- Registered Extension Number
-
145
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
John Kessenich @johnkslang
-
- Last Modified Date
-
2017-03-26
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
John Kessenich, Google
-
The VK_KHR_relaxed_block_layout extension allows implementations to
indicate they can support more variation in block Offset decorations.
For example, placing a vector of three floats at an offset of 16*N + 4.
See Offset and Stride Assignment for details.
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Version History
-
Revision 1, 2017-03-26 (JohnK)
VK_KHR_sampler_mirror_clamp_to_edge
- Name String
-
VK_KHR_sampler_mirror_clamp_to_edge - Extension Type
-
Device extension
- Registered Extension Number
-
15
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Tobias Hector @tobski
-
- Last Modified Date
-
2016-02-16
- Contributors
-
-
Tobias Hector, Imagination Technologies
-
VK_KHR_sampler_mirror_clamp_to_edge extends the set of sampler address
modes to include an additional mode
(VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE) that effectively uses a
texture map twice as large as the original image in which the additional
half of the new image is a mirror image of the original image.
This new mode relaxes the need to generate images whose opposite edges match by using the original image to generate a matching “mirror image”. This mode allows the texture to be mirrored only once in the negative s, t, and r directions.
New Enum Constants
-
Extending VkSamplerAddressMode:
-
VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE
-
Example
Creating a sampler with the new address mode in each dimension
VkSamplerCreateInfo createInfo =
{
VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO // sType
// Other members set to application-desired values
};
createInfo.addressModeU = VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE;
createInfo.addressModeV = VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE;
createInfo.addressModeW = VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE;
VkSampler sampler;
VkResult result = vkCreateSampler(
device,
&createInfo,
&sampler);
Version History
-
Revision 1, 2016-02-16 (Tobias Hector)
-
Initial draft
-
VK_KHR_sampler_ycbcr_conversion
- Name String
-
VK_KHR_sampler_ycbcr_conversion - Extension Type
-
Device extension
- Registered Extension Number
-
157
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_maintenance1 -
Requires
VK_KHR_bind_memory2 -
Requires
VK_KHR_get_memory_requirements2
-
- Contact
-
-
Andrew Garrard @fluppeteer
-
- Last Modified Date
-
2017-08-11
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Promoted to Vulkan 1.1 Core
-
This extension interacts with
VK_EXT_debug_report
-
- Contributors
-
-
Andrew Garrard, Samsung Electronics
-
Tobias Hector, Imagination Technologies
-
James Jones, NVIDIA
-
Daniel Koch, NVIDIA
-
Daniel Rakos, AMD
-
Romain Guy, Google
-
Jesse Hall, Google
-
Tom Cooksey, ARM Ltd
-
Jeff Leger, Qualcomm Technologies, Inc
-
Jan-Harald Fredriksen, ARM Ltd
-
Jan Outters, Samsung Electronics
-
Alon Or-bach, Samsung Electronics
-
Michael Worcester, Imagination Technologies
-
Jeff Bolz, NVIDIA
-
Tony Zlatinski, NVIDIA
-
Matthew Netsch, Qualcomm Technologies, Inc
-
This extension provides the ability to perform specified color space conversions during texture sampling operations. It also adds a selection of multi-planar formats, including the ability to bind memory to the planes of an image collectively or separately.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_CREATE_INFO_KHR -
VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_INFO_KHR -
VK_STRUCTURE_TYPE_BIND_IMAGE_PLANE_MEMORY_INFO_KHR -
VK_STRUCTURE_TYPE_IMAGE_PLANE_MEMORY_REQUIREMENTS_INFO_KHR -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLER_YCBCR_CONVERSION_FEATURES_KHR
-
-
Extending VkFormat:
-
VK_FORMAT_G8B8G8R8_422_UNORM_KHR -
VK_FORMAT_B8G8R8G8_422_UNORM_KHR -
VK_FORMAT_G8_B8_R8_3PLANE_420_UNORM_KHR -
VK_FORMAT_G8_B8R8_2PLANE_420_UNORM_KHR -
VK_FORMAT_G8_B8_R8_3PLANE_422_UNORM_KHR -
VK_FORMAT_G8_B8R8_2PLANE_422_UNORM_KHR -
VK_FORMAT_G8_B8_R8_3PLANE_444_UNORM_KHR -
VK_FORMAT_R10X6_UNORM_PACK16_KHR -
VK_FORMAT_R10X6G10X6_UNORM_2PACK16_KHR -
VK_FORMAT_R10X6G10X6B10X6A10X6_UNORM_4PACK16_KHR -
VK_FORMAT_G10X6B10X6G10X6R10X6_422_UNORM_4PACK16_KHR -
VK_FORMAT_B10X6G10X6R10X6G10X6_422_UNORM_4PACK16_KHR -
VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_420_UNORM_3PACK16_KHR -
VK_FORMAT_G10X6_B10X6R10X6_2PLANE_420_UNORM_3PACK16_KHR -
VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_422_UNORM_3PACK16_KHR -
VK_FORMAT_G10X6_B10X6R10X6_2PLANE_422_UNORM_3PACK16_KHR -
VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_444_UNORM_3PACK16_KHR -
VK_FORMAT_R12X4_UNORM_PACK16_KHR -
VK_FORMAT_R12X4G12X4_UNORM_2PACK16_KHR -
VK_FORMAT_R12X4G12X4B12X4A12X4_UNORM_4PACK16_KHR -
VK_FORMAT_G12X4B12X4G12X4R12X4_422_UNORM_4PACK16_KHR -
VK_FORMAT_B12X4G12X4R12X4G12X4_422_UNORM_4PACK16_KHR -
VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_420_UNORM_3PACK16_KHR -
VK_FORMAT_G12X4_B12X4R12X4_2PLANE_420_UNORM_3PACK16_KHR -
VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_422_UNORM_3PACK16_KHR -
VK_FORMAT_G12X4_B12X4R12X4_2PLANE_422_UNORM_3PACK16_KHR -
VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_444_UNORM_3PACK16_KHR -
VK_FORMAT_G16B16G16R16_422_UNORM_KHR -
VK_FORMAT_B16G16R16G16_422_UNORM_KHR -
VK_FORMAT_G16_B16_R16_3PLANE_420_UNORM_KHR -
VK_FORMAT_G16_B16R16_2PLANE_420_UNORM_KHR -
VK_FORMAT_G16_B16_R16_3PLANE_422_UNORM_KHR -
VK_FORMAT_G16_B16R16_2PLANE_422_UNORM_KHR -
VK_FORMAT_G16_B16_R16_3PLANE_444_UNORM_KHR
-
-
Extending VkImageAspectFlagBits:
-
VK_IMAGE_ASPECT_PLANE_0_BIT_KHR -
VK_IMAGE_ASPECT_PLANE_1_BIT_KHR -
VK_IMAGE_ASPECT_PLANE_2_BIT_KHR
-
-
Extending VkImageCreateFlagBits:
-
VK_IMAGE_CREATE_DISJOINT_BIT_KHR
-
-
Extending VkFormatFeatureFlagBits:
-
VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT_KHR -
VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT_KHR -
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BIT_KHR -
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_SEPARATE_RECONSTRUCTION_FILTER_BIT_KHR -
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT_KHR -
VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_FORCEABLE_BIT_KHR -
VK_FORMAT_FEATURE_DISJOINT_BIT_KHR
-
New Structures
New Objects
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
Version History
-
Revision 1, 2017-01-24 (Andrew Garrard)
-
Initial draft
-
-
Revision 2, 2017-01-25 (Andrew Garrard)
-
After initial feedback
-
-
Revision 3, 2017-01-27 (Andrew Garrard)
-
Higher bit depth formats, renaming, swizzle
-
-
Revision 4, 2017-02-22 (Andrew Garrard)
-
Added query function, formats as RGB, clarifications
-
-
Revision 5, 2017-04 (Andrew Garrard)
-
Simplified query and removed output conversions
-
-
Version 6, 2017-4-24 (Andrew Garrard)
-
Tidying, incorporated new image query, restored transfer functions
-
-
Version 7, 2017-04-25 (Andrew Garrard)
-
Added cosited option/midpoint requirement for formats, "bypassConversion"
-
-
Version 8, 2017-04-25 (Andrew Garrard)
-
Simplified further
-
-
Version 9, 2017-04-27 (Andrew Garrard)
-
Disjoint no more
-
-
Version 10, 2017-04-28 (Andrew Garrard)
-
Restored disjoint
-
-
Version 11, 2017-04-29 (Andrew Garrard)
-
Now Ycbcr conversion, and KHR
-
-
Version 12, 2017-06-06 (Andrew Garrard)
-
Added conversion to image view creation
-
-
Version 13, 2017-07-13 (Andrew Garrard)
-
Allowed cosited-only chroma samples for formats
-
-
Version 14, 2017-08-11 (Andrew Garrard)
-
Reflected quantization changes in BT.2100-1
-
VK_KHR_shader_draw_parameters
- Name String
-
VK_KHR_shader_draw_parameters - Extension Type
-
Device extension
- Registered Extension Number
-
64
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Daniel Koch @dgkoch
-
- Last Modified Date
-
2017-09-05
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Requires the SPV_KHR_shader_draw_parameters SPIR-V extension.
-
Requires GL_ARB_shader_draw_parameters for GLSL source languages.
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Daniel Koch, NVIDIA Corporation
-
Jeff Bolz, NVIDIA
-
Daniel Rakos, AMD
-
Jan-Harald Fredriksen, ARM
-
John Kessenich, Google
-
Stuart Smith, IMG
-
This extension adds support for the following SPIR-V extension in Vulkan:
-
SPV_KHR_shader_draw_parameters
The extension provides access to three additional built-in shader variables in Vulkan:
-
BaseInstance, which contains thefirstInstanceparameter passed to draw commands, -
BaseVertex, which contains thefirstVertex/vertexOffsetparameter passed to draw commands, and -
DrawIndex, which contains the index of the draw call currently being processed from an indirect draw call.
When using GLSL source-based shader languages, the following variables from GL_ARB_shader_draw_parameters can map to these SPIR-V built-in decorations:
-
in int gl_BaseInstanceARB;→BaseInstance, -
in int gl_BaseVertexARB;→BaseVertex, and -
in int gl_DrawIDARB;→DrawIndex.
New Object Types
None.
New Enum Constants
None.
New Enums
None.
New Structures
None.
New Functions
None.
New Built-In Variables
New SPIR-V Capabilities
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, however a feature bit was added to distinguish whether it’s actually available or not.
Issues
1) Is this the same functionality as GL_ARB_shader_draw_parameters?
RESOLVED: It’s actually a superset as it also adds in support for arrayed drawing commands.
In GL for GL_ARB_shader_draw_parameters, gl_BaseVertexARB holds the
integer value passed to the parameter to the command that resulted in the
current shader invocation.
In the case where the command has no baseVertex parameter, the value of
gl_BaseVertexARB is zero.
This means that gl_BaseVertexARB = baseVertex (for
glDrawElements commands with baseVertex) or 0.
In particular there are no glDrawArrays commands that take a
baseVertex parameter.
Now in Vulkan, we have BaseVertex = vertexOffset (for indexed
drawing commands) or firstVertex (for arrayed drawing commands), and
so Vulkan’s version is really a superset of GL functionality.
Version History
-
Revision 1, 2016-10-05 (Daniel Koch)
-
Internal revisions
-
VK_KHR_shared_presentable_image
- Name String
-
VK_KHR_shared_presentable_image - Extension Type
-
Device extension
- Registered Extension Number
-
112
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_swapchain -
Requires
VK_KHR_get_surface_capabilities2
-
- Contact
-
-
Alon Or-bach @alonorbach
-
- Last Modified Date
-
2017-03-20
- IP Status
-
No known IP claims.
- Contributors
-
-
Alon Or-bach, Samsung Electronics
-
Ian Elliott, Google
-
Jesse Hall, Google
-
Pablo Ceballos, Google
-
Chris Forbes, Google
-
Jeff Juliano, NVIDIA
-
James Jones, NVIDIA
-
Daniel Rakos, AMD
-
Tobias Hector, Imagination Technologies
-
Graham Connor, Imagination Technologies
-
Michael Worcester, Imagination Technologies
-
Cass Everitt, Oculus
-
Johannes Van Waveren, Oculus
-
This extension extends VK_KHR_swapchain to enable creation of a shared
presentable image.
This allows the application to use the image while the presention engine is
accessing it, in order to reduce the latency between rendering and
presentation.
New Object Types
None.
New Enum Constants
-
Extending VkPresentModeKHR:
-
VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR -
VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR
-
-
Extending VkImageLayout:
-
VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR
-
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_SHARED_PRESENT_SURFACE_CAPABILITIES_KHR
-
New Enums
None.
New Structures
New Functions
Issues
1) Should we allow a Vulkan WSI swapchain to toggle between normal usage and shared presentation usage?
RESOLVED: No. WSI swapchains are typically recreated with new properties instead of having their properties changed. This can also save resources, assuming that fewer images are needed for shared presentation, and assuming that most VR applications do not need to switch between normal and shared usage.
2) Should we have a query for determining how the presentation engine refresh is triggered?
RESOLVED: Yes. This is done via which presentation modes a surface supports.
3) Should the object representing a shared presentable image be an extension of a VkSwapchainKHR or a separate object?
RESOLVED: Extension of a swapchain due to overlap in creation properties and to allow common functionality between shared and normal presentable images and swapchains.
4) What should we call the extension and the new structures it creates?
RESOLVED: Shared presentable image / shared present.
5) Should the minImageCount and presentMode values of the
VkSwapchainCreateInfoKHR be ignored, or required to be compatible
values?
RESOLVED: minImageCount must be set to 1, and presentMode
should be set to either VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR or
VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR.
6) What should the layout of the shared presentable image be?
RESOLVED: After acquiring the shared presentable image, the application
must transition it to the VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR layout
prior to it being used.
After this intial transition, any image usage that was requested during
swapchain creation can be performed on the image without layout transitions
being performed.
7) Do we need a new API for the trigger to refresh new content?
RESOLVED: vkQueuePresentKHR to act as API to trigger a refresh, as will allow combination with other compatible extensions to vkQueuePresentKHR.
8) How should an application detect a VK_ERROR_OUT_OF_DATE_KHR error
on a swapchain using the VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR
present mode?
RESOLVED: Introduce vkGetSwapchainStatusKHR to allow applications to query the status of a swapchain using a shared presentation mode.
9) What should subsequent calls to vkQueuePresentKHR for
VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR swapchains be defined to
do?
RESOLVED: State that implementations may use it as a hint for updated content.
10) Can the ownership of a shared presentable image be transferred to a different queue?
RESOLVED: No.
It is not possible to transfer ownership of a shared presentable image
obtained from a swapchain created using VK_SHARING_MODE_EXCLUSIVE
after it has been presented.
11) How should vkQueueSubmit behave if a command buffer uses an image
from an VK_ERROR_OUT_OF_DATE_KHR swapchain?
RESOLVED: vkQueueSubmit is expected to return the
VK_ERROR_DEVICE_LOST error.
12) Can Vulkan provide any guarantee on the order of rendering, to enable beam chasing?
RESOLVED: This could be achieved via use of render passes to ensure strip rendering.
Version History
-
Revision 1, 2017-03-20 (Alon Or-bach)
-
Internal revisions
-
VK_KHR_storage_buffer_storage_class
- Name String
-
VK_KHR_storage_buffer_storage_class - Extension Type
-
Device extension
- Registered Extension Number
-
132
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Alexander Galazin @alegal-arm
-
- Last Modified Date
-
2017-09-05
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
This extension requires the SPV_KHR_storage_buffer_storage_class SPIR-V extension.
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
Alexander Galazin, ARM
-
David Neto, Google
-
This extension adds support for the following SPIR-V extension in Vulkan:
-
SPV_KHR_storage_buffer_storage_class
This extension provides a new SPIR-V StorageBuffer storage class.
A Block-decorated object in this class is equivalent to a
BufferBlock-decorated object in the Uniform storage class.
New Enum Constants
None.
New Structures
None.
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1.
Issues
None.
Version History
-
Revision 1, 2017-03-23 (Alexander Galazin)
-
Initial draft
-
VK_KHR_surface
- Name String
-
VK_KHR_surface - Extension Type
-
Instance extension
- Registered Extension Number
-
1
- Revision
-
25
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
James Jones @cubanismo,Ian Elliott @ianelliottus
-
- Last Modified Date
-
2016-08-25
- IP Status
-
No known IP claims.
- Contributors
-
-
Patrick Doane, Blizzard
-
Ian Elliott, LunarG
-
Jesse Hall, Google
-
James Jones, NVIDIA
-
David Mao, AMD
-
Norbert Nopper, Freescale
-
Alon Or-bach, Samsung
-
Daniel Rakos, AMD
-
Graham Sellers, AMD
-
Jeff Vigil, Qualcomm
-
Chia-I Wu, LunarG
-
Jason Ekstrand, Intel
-
The VK_KHR_surface extension is an instance extension.
It introduces VkSurfaceKHR objects, which abstract native platform
surface or window objects for use with Vulkan.
It also provides a way to determine whether a queue family in a physical
device supports presenting to particular surface.
Separate extensions for each platform provide the mechanisms for creating
VkSurfaceKHR objects, but once created they may be used in this and
other platform-independent extensions, in particular the
VK_KHR_swapchain extension.
New Object Types
New Enum Constants
-
Extending VkResult:
-
VK_ERROR_SURFACE_LOST_KHR -
VK_ERROR_NATIVE_WINDOW_IN_USE_KHR
-
New Enums
New Structures
New Functions
Examples
|
Note
The example code for the |
Issues
1) Should this extension include a method to query whether a physical device supports presenting to a specific window or native surface on a given platform?
RESOLVED: Yes. Without this, applications would need to create a device instance to determine whether a particular window can be presented to. Knowing that a device supports presentation to a platform in general is not sufficient, as a single machine might support multiple seats, or instances of the platform that each use different underlying physical devices. Additionally, on some platforms, such as the X Window System, different drivers and devices might be used for different windows depending on which section of the desktop they exist on.
2) Should the vkGetPhysicalDeviceSurfaceCapabilitiesKHR,
vkGetPhysicalDeviceSurfaceFormatsKHR, and
vkGetPhysicalDeviceSurfacePresentModesKHR functions from
VK_KHR_swapchain be modified to operate on physical devices and moved
to this extension to implement the resolution of issue 1?
RESOLVED: No, separate query functions are needed, as the purposes served
are similar but incompatible.
The vkGetPhysicalDeviceSurface*KHR functions return information that
could potentially depend on an initialized device.
For example, the formats supported for presentation to the surface might
vary depending on which device extensions are enabled.
The query introduced to resolve issue 1 should be used only to query generic
driver or platform properties.
The physical device parameter is intended to serve only as an identifier
rather than a stateful object.
3) Should Vulkan include support Xlib or XCB as the API for accessing the X Window System platform?
RESOLVED: Both. XCB is a more modern and efficient API, but Xlib usage is deeply ingrained in many applications and likely will remain in use for the foreseeable future. Not all drivers necessarily need to support both, but including both as options in the core specification will probably encourage support, which should in turn ease adoption of the Vulkan API in older codebases. Additionally, the performance improvements possible with XCB likely will not have a measurable impact on the performance of Vulkan presentation and other minimal window system interactions defined here.
4) Should the GBM platform be included in the list of platform enums?
RESOLVED: Deferred, and will be addressed with a platform-specific extension to be written in the future.
Version History
-
Revision 1, 2015-05-20 (James Jones)
-
Initial draft, based on LunarG KHR spec, other KHR specs, patches attached to bugs.
-
-
Revision 2, 2015-05-22 (Ian Elliott)
-
Created initial Description section.
-
Removed query for whether a platform requires the use of a queue for presentation, since it was decided that presentation will always be modeled as being part of the queue.
-
Fixed typos and other minor mistakes.
-
-
Revision 3, 2015-05-26 (Ian Elliott)
-
Improved the Description section.
-
-
Revision 4, 2015-05-27 (James Jones)
-
Fixed compilation errors in example code.
-
-
Revision 5, 2015-06-01 (James Jones)
-
Added issues 1 and 2 and made related spec updates.
-
-
Revision 6, 2015-06-01 (James Jones)
-
Merged the platform type mappings table previously removed from VK_KHR_swapchain with the platform description table in this spec.
-
Added issues 3 and 4 documenting choices made when building the initial list of native platforms supported.
-
-
Revision 7, 2015-06-11 (Ian Elliott)
-
Updated table 1 per input from the KHR TSG.
-
Updated issue 4 (GBM) per discussion with Daniel Stone. He will create a platform-specific extension sometime in the future.
-
-
Revision 8, 2015-06-17 (James Jones)
-
Updated enum-extending values using new convention.
-
Fixed the value of VK_SURFACE_PLATFORM_INFO_TYPE_SUPPORTED_KHR.
-
-
Revision 9, 2015-06-17 (James Jones)
-
Rebased on Vulkan API version 126.
-
-
Revision 10, 2015-06-18 (James Jones)
-
Marked issues 2 and 3 resolved.
-
-
Revision 11, 2015-06-23 (Ian Elliott)
-
Examples now show use of function pointers for extension functions.
-
Eliminated extraneous whitespace.
-
-
Revision 12, 2015-07-07 (Daniel Rakos)
-
Added error section describing when each error is expected to be reported.
-
Replaced the term "queue node index" with "queue family index" in the spec as that is the agreed term to be used in the latest version of the core header and spec.
-
Replaced bool32_t with VkBool32.
-
-
Revision 13, 2015-08-06 (Daniel Rakos)
-
Updated spec against latest core API header version.
-
-
Revision 14, 2015-08-20 (Ian Elliott)
-
Renamed this extension and all of its enumerations, types, functions, etc. This makes it compliant with the proposed standard for Vulkan extensions.
-
Switched from "revision" to "version", including use of the VK_MAKE_VERSION macro in the header file.
-
Did miscellaneous cleanup, etc.
-
-
Revision 15, 2015-08-20 (Ian Elliott—porting a 2015-07-29 change from James Jones)
-
Moved the surface transform enums here from VK_WSI_swapchain so they could be re-used by VK_WSI_display.
-
-
Revision 16, 2015-09-01 (James Jones)
-
Restore single-field revision number.
-
-
Revision 17, 2015-09-01 (James Jones)
-
Fix example code compilation errors.
-
-
Revision 18, 2015-09-26 (Jesse Hall)
-
Replaced VkSurfaceDescriptionKHR with the VkSurfaceKHR object, which is created via layered extensions. Added VkDestroySurfaceKHR.
-
-
Revision 19, 2015-09-28 (Jesse Hall)
-
Renamed from VK_EXT_KHR_swapchain to VK_EXT_KHR_surface.
-
-
Revision 20, 2015-09-30 (Jeff Vigil)
-
Add error result VK_ERROR_SURFACE_LOST_KHR.
-
-
Revision 21, 2015-10-15 (Daniel Rakos)
-
Updated the resolution of issue #2 and include the surface capability queries in this extension.
-
Renamed SurfaceProperties to SurfaceCapabilities as it better reflects that the values returned are the capabilities of the surface on a particular device.
-
Other minor cleanup and consistency changes.
-
-
Revision 22, 2015-10-26 (Ian Elliott)
-
Renamed from VK_EXT_KHR_surface to VK_KHR_surface.
-
-
Revision 23, 2015-11-03 (Daniel Rakos)
-
Added allocation callbacks to vkDestroySurfaceKHR.
-
-
Revision 24, 2015-11-10 (Jesse Hall)
-
Removed VkSurfaceTransformKHR. Use VkSurfaceTransformFlagBitsKHR instead.
-
Rename VkSurfaceCapabilitiesKHR member maxImageArraySize to maxImageArrayLayers.
-
-
Revision 25, 2016-01-14 (James Jones)
-
Moved VK_ERROR_NATIVE_WINDOW_IN_USE_KHR from the VK_KHR_android_surface to the VK_KHR_surface extension.
-
-
2016-08-23 (Ian Elliott)
-
Update the example code, to not have so many characters per line, and to split out a new example to show how to obtain function pointers.
-
-
2016-08-25 (Ian Elliott)
-
A note was added at the beginning of the example code, stating that it will be removed from future versions of the appendix.
-
VK_KHR_swapchain
- Name String
-
VK_KHR_swapchain - Extension Type
-
Device extension
- Registered Extension Number
-
2
- Revision
-
70
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_surface
-
- Contact
-
-
James Jones @cubanismo,Ian Elliott @ianelliottus
-
- Last Modified Date
-
2017-10-06
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Interacts with Vulkan 1.1
-
- Contributors
-
-
Patrick Doane, Blizzard
-
Ian Elliott, LunarG
-
Jesse Hall, Google
-
Mathias Heyer, NVIDIA
-
James Jones, NVIDIA
-
David Mao, AMD
-
Norbert Nopper, Freescale
-
Alon Or-bach, Samsung
-
Daniel Rakos, AMD
-
Graham Sellers, AMD
-
Jeff Vigil, Qualcomm
-
Chia-I Wu, LunarG
-
Jason Ekstrand, Intel
-
Matthaeus G. Chajdas, AMD
-
Ray Smith, ARM
-
The VK_KHR_swapchain extension is the device-level companion to the
VK_KHR_surface extension.
It introduces VkSwapchainKHR objects, which provide the ability to
present rendering results to a surface.
New Object Types
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_SWAPCHAIN_CREATE_INFO_KHR -
VK_STRUCTURE_TYPE_PRESENT_INFO_KHR -
VK_STRUCTURE_TYPE_DEVICE_GROUP_PRESENT_CAPABILITIES_KHR -
VK_STRUCTURE_TYPE_IMAGE_SWAPCHAIN_CREATE_INFO_KHR -
VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_SWAPCHAIN_INFO_KHR -
VK_STRUCTURE_TYPE_ACQUIRE_NEXT_IMAGE_INFO_KHR -
VK_STRUCTURE_TYPE_DEVICE_GROUP_PRESENT_INFO_KHR -
VK_STRUCTURE_TYPE_DEVICE_GROUP_SWAPCHAIN_CREATE_INFO_KHR
-
-
Extending VkImageLayout:
-
VK_IMAGE_LAYOUT_PRESENT_SRC_KHR
-
-
Extending VkResult:
-
VK_SUBOPTIMAL_KHR -
VK_ERROR_OUT_OF_DATE_KHR
-
New Structures
New Functions
Issues
1) Does this extension allow the application to specify the memory backing of the presentable images?
RESOLVED: No. Unlike standard images, the implementation will allocate the memory backing of the presentable image.
2) What operations are allowed on presentable images?
RESOLVED: This is determined by the image usage flags specified when creating the presentable image’s swapchain.
3) Does this extension support MSAA presentable images?
RESOLVED: No. Presentable images are always single-sampled. Multi-sampled rendering must use regular images. To present the rendering results the application must manually resolve the multi- sampled image to a single-sampled presentable image prior to presentation.
4) Does this extension support stereo/multi-view presentable images?
RESOLVED: Yes.
The number of views associated with a presentable image is determined by the
imageArrayLayers specified when creating a swapchain.
All presentable images in a given swapchain use the same array size.
5) Are the layers of stereo presentable images half-sized?
RESOLVED: No. The image extents always match those requested by the application.
6) Do the “present” and “acquire next image” commands operate on a queue? If not, do they need to include explicit semaphore objects to interlock them with queue operations?
RESOLVED: The present command operates on a queue. The image ownership operation it represents happens in order with other operations on the queue, so no explicit semaphore object is required to synchronize its actions.
Applications may want to acquire the next image in separate threads from those in which they manage their queue, or in multiple threads. To make such usage easier, the acquire next image command takes a semaphore to signal as a method of explicit synchronization. The application must later queue a wait for this semaphore before queuing execution of any commands using the image.
7) Does vkAcquireNextImageKHR block if no images are available?
RESOLVED: The command takes a timeout parameter.
Special values for the timeout are 0, which makes the call a non-blocking
operation, and UINT64_MAX, which blocks indefinitely.
Values in between will block for up to the specified time.
The call will return when an image becomes available or an error occurs.
It may, but is not required to, return before the specified timeout expires
if the swapchain becomes out of date.
8) Can multiple presents be queued using one vkQueuePresentKHR call?
RESOLVED: Yes. VkPresentInfoKHR contains a list of swapchains and corresponding image indices that will be presented. When supported, all presentations queued with a single vkQueuePresentKHR call will be applied atomically as one operation. The same swapchain must not appear in the list more than once. Later extensions may provide applications stronger guarantees of atomicity for such present operations, and/or allow them to query whether atomic presentation of a particular group of swapchains is possible.
9) How do the presentation and acquire next image functions notify the application the targeted surface has changed?
RESOLVED: Two new result codes are introduced for this purpose:
-
VK_SUBOPTIMAL_KHR- Presentation will still succeed, subject to the window resize behavior, but the swapchain is no longer configured optimally for the surface it targets. Applications should query updated surface information and recreate their swapchain at the next convenient opportunity. -
VK_ERROR_OUT_OF_DATE_KHR- Failure. The swapchain is no longer compatible with the surface it targets. The application must query updated surface information and recreate the swapchain before presentation will succeed.
These can be returned by both vkAcquireNextImageKHR and vkQueuePresentKHR.
10) Does the vkAcquireNextImageKHR command return a semaphore to the application via an output parameter, or accept a semaphore to signal from the application as an object handle parameter?
RESOLVED: Accept a semaphore to signal as an object handle. This avoids the need to specify whether the application must destroy the semaphore or whether it is owned by the swapchain, and if the latter, what its lifetime is and whether it can be re-used for other operations once it is received from vkAcquireNextImageKHR.
11) What types of swapchain queuing behavior should be exposed? Options include swap interval specification, mailbox/most recent vs. FIFO queue management, targeting specific vertical blank intervals or absolute times for a given present operation, and probably others. For some of these, whether they are specified at swapchain creation time or as per-present parameters needs to be decided as well.
RESOLVED: The base swapchain extension will expose 3 possible behaviors (of which, FIFO will always be supported):
-
Immediate present: Does not wait for vertical blanking period to update the current image, likely resulting in visible tearing. No internal queue is used. Present requests are applied immediately.
-
Mailbox queue: Waits for the next vertical blanking period to update the current image. No tearing should be observed. An internal single-entry queue is used to hold pending presentation requests. If the queue is full when a new presentation request is received, the new request replaces the existing entry, and any images associated with the prior entry become available for re-use by the application.
-
FIFO queue: Waits for the next vertical blanking period to update the current image. No tearing should be observed. An internal queue containing
numSwapchainImages- 1 entries is used to hold pending presentation requests. New requests are appended to the end of the queue, and one request is removed from the beginning of the queue and processed during each vertical blanking period in which the queue is non-empty
Not all surfaces will support all of these modes, so the modes supported will be returned using a surface info query. All surfaces must support the FIFO queue mode. Applications must choose one of these modes up front when creating a swapchain. Switching modes can be accomplished by recreating the swapchain.
12) Can VK_PRESENT_MODE_MAILBOX_KHR provide non-blocking guarantees
for vkAcquireNextImageKHR? If so, what is the proper criteria?
RESOLVED: Yes. The difficulty is not immediately obvious here. Naively, if at least 3 images are requested, mailbox mode should always have an image available for the application if the application does not own any images when the call to vkAcquireNextImageKHR was made. However, some presentation engines may have more than one “current” image, and would still need to block in some cases. The right requirement appears to be that if the application allocates the surface’s minimum number of images + 1 then it is guaranteed non-blocking behavior when it does not currently own any images.
13) Is there a way to create and initialize a new swapchain for a surface
that has generated a VK_SUBOPTIMAL_KHR return code while still using
the old swapchain?
RESOLVED: Not as part of this specification. This could be useful to allow the application to create an “optimal” replacement swapchain and rebuild all its command buffers using it in a background thread at a low priority while continuing to use the “suboptimal” swapchain in the main thread. It could probably use the same “atomic replace” semantics proposed for recreating direct-to-device swapchains without incurring a mode switch. However, after discussion, it was determined some platforms probably could not support concurrent swapchains for the same surface though, so this will be left out of the base KHR extensions. A future extension could add this for platforms where it is supported.
14) Should there be a special value for
VkSurfaceCapabilitiesKHR::maxImageCount to indicate there are no
practical limits on the number of images in a swapchain?
RESOLVED: Yes. There where often be cases where there is no practical limit to the number of images in a swapchain other than the amount of available resources (I.e., memory) in the system. Trying to derive a hard limit from things like memory size is prone to failure. It is better in such cases to leave it to applications to figure such soft limits out via trial/failure iterations.
15) Should there be a special value for
VkSurfaceCapabilitiesKHR::currentExtent to indicate the size of
the platform surface is undefined?
RESOLVED: Yes. On some platforms (Wayland, for example), the surface size is defined by the images presented to it rather than the other way around.
16) Should there be a special value for
VkSurfaceCapabilitiesKHR::maxImageExtent to indicate there is no
practical limit on the surface size?
RESOLVED: No. It seems unlikely such a system would exist. 0 could be used to indicate the platform places no limits on the extents beyond those imposed by Vulkan for normal images, but this query could just as easily return those same limits, so a special “unlimited” value does not seem useful for this field.
17) How should surface rotation and mirroring be exposed to applications? How do they specify rotation and mirroring transforms applied prior to presentation?
RESOLVED: Applications can query both the supported and current transforms
of a surface.
Both are specified relative to the device’s “natural” display rotation and
direction.
The supported transforms indicates which orientations the presentation
engine accepts images in.
For example, a presentation engine that does not support transforming
surfaces as part of presentation, and which is presenting to a surface that
is displayed with a 90-degree rotation, would return only one supported
transform bit: VK_SURFACE_TRANSFORM_ROT90_BIT_KHR.
Applications must transform their rendering by the transform they specify
when creating the swapchain in preTransform field.
18) Can surfaces ever not support VK_MIRROR_NONE? Can they support
vertical and horizontal mirroring simultaneously? Relatedly, should
VK_MIRROR_NONE[_BIT] be zero, or bit one, and should applications be
allowed to specify multiple pre and current mirror transform bits, or
exactly one?
RESOLVED: Since some platforms may not support presenting with a transform
other than the native window’s current transform, and prerotation/mirroring
are specified relative to the device’s natural rotation and direction,
rather than relative to the surface’s current rotation and direction, it is
necessary to express lack of support for no mirroring.
To allow this, the MIRROR_NONE enum must occupy a bit in the flags.
Since MIRROR_NONE must be a bit in the bitmask rather than a bitmask
with no values set, allowing more than one bit to be set in the bitmask
would make it possible to describe undefined transforms such as
VK_MIRROR_NONE_BIT | VK_MIRROR_HORIZONTAL_BIT, or a transform
that includes both “no mirroring” and “horizontal mirroring”
simultaneously.
Therefore, it is desirable to allow specifying all supported mirroring
transforms using only one bit.
The question then becomes, should there be a
VK_MIRROR_HORIZONTAL_AND_VERTICAL_BIT to represent a simultaneous
horizontal and vertical mirror transform? However, such a transform is
equivalent to a 180 degree rotation, so presentation engines and
applications that wish to support or use such a transform can express it
through rotation instead.
Therefore, 3 exclusive bits are sufficient to express all needed mirroring
transforms.
19) Should support for sRGB be required?
RESOLVED: In the advent of UHD and HDR display devices, proper color space information is vital to the display pipeline represented by the swapchain. The app can discover the supported format/color-space pairs and select a pair most suited to its rendering needs. Currently only the sRGB color space is supported, future extensions may provide support for more color spaces. See issues 23 and 24.
20) Is there a mechanism to modify or replace an existing swapchain with one targeting the same surface?
RESOLVED: Yes. This is described above in the text.
21) Should there be a way to set prerotation and mirroring using native APIs when presenting using a Vulkan swapchain?
RESOLVED: Yes.
The transforms that can be expressed in this extension are a subset of those
possible on native platforms.
If a platform exposes a method to specify the transform of presented images
for a given surface using native methods and exposes more transforms or
other properties for surfaces than Vulkan supports, it might be impossible,
difficult, or inconvenient to set some of those properties using Vulkan KHR
extensions and some using the native interfaces.
To avoid overwriting properties set using native commands when presenting
using a Vulkan swapchain, the application can set the pretransform to
“inherit”, in which case the current native properties will be used, or if
none are available, a platform-specific default will be used.
Platforms that do not specify a reasonable default or do not provide native
mechanisms to specify such transforms should not include the inherit bits in
the supportedTransforms bitmask they return in
VkSurfaceCapabilitiesKHR.
22) Should the content of presentable images be clipped by objects obscuring their target surface?
RESOLVED: Applications can choose which behavior they prefer. Allowing the content to be clipped could enable more optimal presentation methods on some platforms, but some applications might rely on the content of presentable images to perform techniques such as partial updates or motion blurs.
23) What is the purpose of specifying a VkColorSpaceKHR along with VkFormat when creating a swapchain?
RESOLVED: While Vulkan itself is color space agnostic (e.g. even the
meaning of R, G, B and A can be freely defined by the rendering
application), the swapchain eventually will have to present the images on a
display device with specific color reproduction characteristics.
If any color space transformations are necessary before an image can be
displayed, the color space of the presented image must be known to the
swapchain.
A swapchain will only support a restricted set of color format and -space
pairs.
This set can be discovered via vkGetPhysicalDeviceSurfaceFormatsKHR.
As it can be expected that most display devices support the sRGB color
space, at least one format/color-space pair has to be exposed, where the
color space is VK_COLOR_SPACE_SRGB_NONLINEAR.
24) How are sRGB formats and the sRGB color space related?
RESOLVED: While Vulkan exposes a number of SRGB texture formats, using
such formats does not guarantee working in a specific color space.
It merely means that the hardware can directly support applying the
non-linear transfer functions defined by the sRGB standard color space when
reading from or writing to images of that these formats.
Still, it is unlikely that a swapchain will expose a *_SRGB format
along with any color space other than VK_COLOR_SPACE_SRGB_NONLINEAR.
On the other hand, non-*_SRGB formats will be very likely exposed in
pair with a SRGB color space.
This means, the hardware will not apply any transfer function when reading
from or writing to such images, yet they will still be presented on a device
with sRGB display characteristics.
In this case the application is responsible for applying the transfer
function, for instance by using shader math.
25) How are the lifetime of surfaces and swapchains targeting them related?
RESOLVED: A surface must outlive any swapchains targeting it. A VkSurfaceKHR owns the binding of the native window to the Vulkan driver.
26) How can the client control the way the alpha channel of swapchain images is treated by the presentation engine during compositing?
RESOLVED: We should add new enum values to allow the client to negotiate
with the presentation engine on how to treat image alpha values during the
compositing process.
Since not all platforms can practically control this through the Vulkan
driver, a value of VK_COMPOSITE_ALPHA_INHERIT_BIT_KHR is provided like
for surface transforms.
27) Is vkCreateSwapchainKHR the right function to return
VK_ERROR_NATIVE_WINDOW_IN_USE_KHR, or should the various
platform-specific VkSurfaceKHR factory functions catch this error
earlier?
RESOLVED: For most platforms, the VkSurfaceKHR structure is a simple container holding the data that identifies a native window or other object representing a surface on a particular platform. For the surface factory functions to return this error, they would likely need to register a reference on the native objects with the native display server somehow, and ensure no other such references exist. Surfaces were not intended to be that heavyweight.
Swapchains are intended to be the objects that directly manipulate native windows and communicate with the native presentation mechanisms. Swapchains will already need to communicate with the native display server to negotiate allocation and/or presentation of presentable images for a native surface. Therefore, it makes more sense for swapchain creation to be the point at which native object exclusivity is enforced. Platforms may choose to enforce further restrictions on the number of VkSurfaceKHR objects that may be created for the same native window if such a requirement makes sense on a particular platform, but a global requirement is only sensible at the swapchain level.
Examples
|
Note
The example code for the |
Version History
-
Revision 1, 2015-05-20 (James Jones)
-
Initial draft, based on LunarG KHR spec, other KHR specs, patches attached to bugs.
-
-
Revision 2, 2015-05-22 (Ian Elliott)
-
Made many agreed-upon changes from 2015-05-21 KHR TSG meeting. This includes using only a queue for presentation, and having an explicit function to acquire the next image.
-
Fixed typos and other minor mistakes.
-
-
Revision 3, 2015-05-26 (Ian Elliott)
-
Improved the Description section.
-
Added or resolved issues that were found in improving the Description. For example, pSurfaceDescription is used consistently, instead of sometimes using pSurface.
-
-
Revision 4, 2015-05-27 (James Jones)
-
Fixed some grammatical errors and typos
-
Filled in the description of imageUseFlags when creating a swapchain.
-
Added a description of swapInterval.
-
Replaced the paragraph describing the order of operations on a queue for image ownership and presentation.
-
-
Revision 5, 2015-05-27 (James Jones)
-
Imported relevant issues from the (abandoned) vk_wsi_persistent_swapchain_images extension.
-
Added issues 6 and 7, regarding behavior of the acquire next image and present commands with respect to queues.
-
Updated spec language and examples to align with proposed resolutions to issues 6 and 7.
-
-
Revision 6, 2015-05-27 (James Jones)
-
Added issue 8, regarding atomic presentation of multiple swapchains
-
Updated spec language and examples to align with proposed resolution to issue 8.
-
-
Revision 7, 2015-05-27 (James Jones)
-
Fixed compilation errors in example code, and made related spec fixes.
-
-
Revision 8, 2015-05-27 (James Jones)
-
Added issue 9, and the related VK_SUBOPTIMAL_KHR result code.
-
Renamed VK_OUT_OF_DATE_KHR to VK_ERROR_OUT_OF_DATE_KHR.
-
-
Revision 9, 2015-05-27 (James Jones)
-
Added inline proposed resolutions (marked with [JRJ]) to some XXX questions/issues. These should be moved to the issues section in a subsequent update if the proposals are adopted.
-
-
Revision 10, 2015-05-28 (James Jones)
-
Converted vkAcquireNextImageKHR back to a non-queue operation that uses a VkSemaphore object for explicit synchronization.
-
Added issue 10 to determine whether vkAcquireNextImageKHR generates or returns semaphores, or whether it operates on a semaphore provided by the application.
-
-
Revision 11, 2015-05-28 (James Jones)
-
Marked issues 6, 7, and 8 resolved.
-
Renamed VkSurfaceCapabilityPropertiesKHR to VkSurfacePropertiesKHR to better convey the mutable nature of the info it contains.
-
-
Revision 12, 2015-05-28 (James Jones)
-
Added issue 11 with a proposed resolution, and the related issue 12.
-
Updated various sections of the spec to match the proposed resolution to issue 11.
-
-
Revision 13, 2015-06-01 (James Jones)
-
Moved some structures to VK_EXT_KHR_swap_chain to resolve the spec’s issues 1 and 2.
-
-
Revision 14, 2015-06-01 (James Jones)
-
Added code for example 4 demonstrating how an application might make use of the two different present and acquire next image KHR result codes.
-
Added issue 13.
-
-
Revision 15, 2015-06-01 (James Jones)
-
Added issues 14 - 16 and related spec language.
-
Fixed some spelling errors.
-
Added language describing the meaningful return values for vkAcquireNextImageKHR and vkQueuePresentKHR.
-
-
Revision 16, 2015-06-02 (James Jones)
-
Added issues 17 and 18, as well as related spec language.
-
Removed some erroneous text added by mistake in the last update.
-
-
Revision 17, 2015-06-15 (Ian Elliott)
-
Changed special value from "-1" to "0" so that the data types can be unsigned.
-
-
Revision 18, 2015-06-15 (Ian Elliott)
-
Clarified the values of VkSurfacePropertiesKHR::minImageCount and the timeout parameter of the vkAcquireNextImageKHR function.
-
-
Revision 19, 2015-06-17 (James Jones)
-
Misc. cleanup. Removed resolved inline issues and fixed typos.
-
Fixed clarification of VkSurfacePropertiesKHR::minImageCount made in version 18.
-
Added a brief "Image Ownership" definition to the list of terms used in the spec.
-
-
Revision 20, 2015-06-17 (James Jones)
-
Updated enum-extending values using new convention.
-
-
Revision 21, 2015-06-17 (James Jones)
-
Added language describing how to use VK_IMAGE_LAYOUT_PRESENT_SOURCE_KHR.
-
Cleaned up an XXX comment regarding the description of which queues vkQueuePresentKHR can be used on.
-
-
Revision 22, 2015-06-17 (James Jones)
-
Rebased on Vulkan API version 126.
-
-
Revision 23, 2015-06-18 (James Jones)
-
Updated language for issue 12 to read as a proposed resolution.
-
Marked issues 11, 12, 13, 16, and 17 resolved.
-
Temporarily added links to the relevant bugs under the remaining unresolved issues.
-
Added issues 19 and 20 as well as proposed resolutions.
-
-
Revision 24, 2015-06-19 (Ian Elliott)
-
Changed special value for VkSurfacePropertiesKHR::currentExtent back to "-1" from "0". This value will never need to be unsigned, and "0" is actually a legal value.
-
-
Revision 25, 2015-06-23 (Ian Elliott)
-
Examples now show use of function pointers for extension functions.
-
Eliminated extraneous whitespace.
-
-
Revision 26, 2015-06-25 (Ian Elliott)
-
Resolved Issues 9 & 10 per KHR TSG meeting.
-
-
Revision 27, 2015-06-25 (James Jones)
-
Added oldSwapchain member to VkSwapchainCreateInfoKHR.
-
-
Revision 28, 2015-06-25 (James Jones)
-
Added the "inherit" bits to the rotation and mirroring flags and the associated issue 21.
-
-
Revision 29, 2015-06-25 (James Jones)
-
Added the "clipped" flag to VkSwapchainCreateInfoKHR, and the associated issue 22.
-
Specified that presenting an image does not modify it.
-
-
Revision 30, 2015-06-25 (James Jones)
-
Added language to the spec that clarifies the behavior of vkCreateSwapchainKHR() when the oldSwapchain field of VkSwapchainCreateInfoKHR is not NULL.
-
-
Revision 31, 2015-06-26 (Ian Elliott)
-
Example of new VkSwapchainCreateInfoKHR members, "oldSwapchain" and "clipped".
-
Example of using VkSurfacePropertiesKHR::{min|max}ImageCount to set VkSwapchainCreateInfoKHR::minImageCount.
-
Rename vkGetSurfaceInfoKHR()'s 4th parameter to "pDataSize", for consistency with other functions.
-
Add macro with C-string name of extension (just to header file).
-
-
Revision 32, 2015-06-26 (James Jones)
-
Minor adjustments to the language describing the behavior of "oldSwapchain"
-
Fixed the version date on my previous two updates.
-
-
Revision 33, 2015-06-26 (Jesse Hall)
-
Add usage flags to VkSwapchainCreateInfoKHR
-
-
Revision 34, 2015-06-26 (Ian Elliott)
-
Rename vkQueuePresentKHR()'s 2nd parameter to "pPresentInfo", for consistency with other functions.
-
-
Revision 35, 2015-06-26 (Jason Ekstrand)
-
Merged the VkRotationFlagBitsKHR and VkMirrorFlagBitsKHR enums into a single VkSurfaceTransformFlagBitsKHR enum.
-
-
Revision 36, 2015-06-26 (Jason Ekstrand)
-
Added a VkSurfaceTransformKHR enum that is not a bitmask. Each value in VkSurfaceTransformKHR corresponds directly to one of the bits in VkSurfaceTransformFlagBitsKHR so transforming from one to the other is easy. Having a separate enum means that currentTransform and preTransform are now unambiguous by definition.
-
-
Revision 37, 2015-06-29 (Ian Elliott)
-
Corrected one of the signatures of vkAcquireNextImageKHR, which had the last two parameters switched from what it is elsewhere in the specification and header files.
-
-
Revision 38, 2015-06-30 (Ian Elliott)
-
Corrected a typo in description of the vkGetSwapchainInfoKHR() function.
-
Corrected a typo in header file comment for VkPresentInfoKHR::sType.
-
-
Revision 39, 2015-07-07 (Daniel Rakos)
-
Added error section describing when each error is expected to be reported.
-
Replaced bool32_t with VkBool32.
-
-
Revision 40, 2015-07-10 (Ian Elliott)
-
Updated to work with version 138 of the "vulkan.h" header. This includes declaring the VkSwapchainKHR type using the new VK_DEFINE_NONDISP_HANDLE macro, and no longer extending VkObjectType (which was eliminated).
-
-
Revision 41 2015-07-09 (Mathias Heyer)
-
Added color space language.
-
-
Revision 42, 2015-07-10 (Daniel Rakos)
-
Updated query mechanism to reflect the convention changes done in the core spec.
-
Removed "queue" from the name of VK_STRUCTURE_TYPE_QUEUE_PRESENT_INFO_KHR to be consistent with the established naming convention.
-
Removed reference to the no longer existing VkObjectType enum.
-
-
Revision 43, 2015-07-17 (Daniel Rakos)
-
Added support for concurrent sharing of swapchain images across queue families.
-
Updated sample code based on recent changes
-
-
Revision 44, 2015-07-27 (Ian Elliott)
-
Noted that support for VK_PRESENT_MODE_FIFO_KHR is required. That is ICDs may optionally support IMMEDIATE and MAILBOX, but must support FIFO.
-
-
Revision 45, 2015-08-07 (Ian Elliott)
-
Corrected a typo in spec file (type and variable name had wrong case for the imageColorSpace member of the VkSwapchainCreateInfoKHR struct).
-
Corrected a typo in header file (last parameter in PFN_vkGetSurfacePropertiesKHR was missing "KHR" at the end of type: VkSurfacePropertiesKHR).
-
-
Revision 46, 2015-08-20 (Ian Elliott)
-
Renamed this extension and all of its enumerations, types, functions, etc. This makes it compliant with the proposed standard for Vulkan extensions.
-
Switched from "revision" to "version", including use of the VK_MAKE_VERSION macro in the header file.
-
Made improvements to several descriptions.
-
Changed the status of several issues from PROPOSED to RESOLVED, leaving no unresolved issues.
-
Resolved several TODOs, did miscellaneous cleanup, etc.
-
-
Revision 47, 2015-08-20 (Ian Elliott—porting a 2015-07-29 change from James Jones)
-
Moved the surface transform enums to VK_WSI_swapchain so they could be re-used by VK_WSI_display.
-
-
Revision 48, 2015-09-01 (James Jones)
-
Various minor cleanups.
-
-
Revision 49, 2015-09-01 (James Jones)
-
Restore single-field revision number.
-
-
Revision 50, 2015-09-01 (James Jones)
-
Update Example #4 to include code that illustrates how to use the oldSwapchain field.
-
-
Revision 51, 2015-09-01 (James Jones)
-
Fix example code compilation errors.
-
-
Revision 52, 2015-09-08 (Matthaeus G. Chajdas)
-
Corrected a typo.
-
-
Revision 53, 2015-09-10 (Alon Or-bach)
-
Removed underscore from SWAP_CHAIN left in VK_STRUCTURE_TYPE_SWAPCHAIN_CREATE_INFO_KHR.
-
-
Revision 54, 2015-09-11 (Jesse Hall)
-
Described the execution and memory coherence requirements for image transitions to and from VK_IMAGE_LAYOUT_PRESENT_SOURCE_KHR.
-
-
Revision 55, 2015-09-11 (Ray Smith)
-
Added errors for destroying and binding memory to presentable images
-
-
Revision 56, 2015-09-18 (James Jones)
-
Added fence argument to vkAcquireNextImageKHR
-
Added example of how to meter a host thread based on presentation rate.
-
-
Revision 57, 2015-09-26 (Jesse Hall)
-
Replace VkSurfaceDescriptionKHR with VkSurfaceKHR.
-
Added issue 25 with agreed resolution.
-
-
Revision 58, 2015-09-28 (Jesse Hall)
-
Renamed from VK_EXT_KHR_device_swapchain to VK_EXT_KHR_swapchain.
-
-
Revision 59, 2015-09-29 (Ian Elliott)
-
Changed vkDestroySwapchainKHR() to return void.
-
-
Revision 60, 2015-10-01 (Jeff Vigil)
-
Added error result VK_ERROR_SURFACE_LOST_KHR.
-
-
Revision 61, 2015-10-05 (Jason Ekstrand)
-
Added the VkCompositeAlpha enum and corresponding structure fields.
-
-
Revision 62, 2015-10-12 (Daniel Rakos)
-
Added VK_PRESENT_MODE_FIFO_RELAXED_KHR.
-
-
Revision 63, 2015-10-15 (Daniel Rakos)
-
Moved surface capability queries to VK_EXT_KHR_surface.
-
-
Revision 64, 2015-10-26 (Ian Elliott)
-
Renamed from VK_EXT_KHR_swapchain to VK_KHR_swapchain.
-
-
Revision 65, 2015-10-28 (Ian Elliott)
-
Added optional pResult member to VkPresentInfoKHR, so that per-swapchain results can be obtained from vkQueuePresentKHR().
-
-
Revision 66, 2015-11-03 (Daniel Rakos)
-
Added allocation callbacks to create and destroy functions.
-
Updated resource transition language.
-
Updated sample code.
-
-
Revision 67, 2015-11-10 (Jesse Hall)
-
Add reserved flags bitmask to VkSwapchainCreateInfoKHR.
-
Modify naming and member ordering to match API style conventions, and so the VkSwapchainCreateInfoKHR image property members mirror corresponding VkImageCreateInfo members but with an 'image' prefix.
-
Make VkPresentInfoKHR::pResults non-const; it is an output array parameter.
-
Make pPresentInfo parameter to vkQueuePresentKHR const.
-
-
Revision 68, 2016-04-05 (Ian Elliott)
-
Moved the "validity" include for vkAcquireNextImage to be in its proper place, after the prototype and list of parameters.
-
Clarified language about presentable images, including how they are acquired, when applications can and cannot use them, etc. As part of this, removed language about "ownership" of presentable images, and replaced it with more-consistent language about presentable images being "acquired" by the application.
-
-
2016-08-23 (Ian Elliott)
-
Update the example code, to use the final API command names, to not have so many characters per line, and to split out a new example to show how to obtain function pointers. This code is more similar to the LunarG "cube" demo program.
-
-
2016-08-25 (Ian Elliott)
-
A note was added at the beginning of the example code, stating that it will be removed from future versions of the appendix.
-
-
Revision 69, 2017-09-07 (Tobias Hector)
-
Added interactions with Vulkan 1.1
-
-
Revision 70, 2017-10-06 (Ian Elliott)
-
Corrected interactions with Vulkan 1.1
-
VK_KHR_variable_pointers
- Name String
-
VK_KHR_variable_pointers - Extension Type
-
Device extension
- Registered Extension Number
-
121
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_storage_buffer_storage_class
-
- Contact
-
-
Jesse Hall @critsec
-
- Last Modified Date
-
2017-09-05
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Requires the SPV_KHR_variable_pointers SPIR-V extension.
-
Promoted to Vulkan 1.1 Core
-
- Contributors
-
-
John Kessenich, Google
-
Neil Henning, Codeplay
-
David Neto, Google
-
Daniel Koch, Nvidia
-
Graeme Leese, Broadcom
-
Weifeng Zhang, Qualcomm
-
Stephen Clarke, Imagination Technologies
-
Jason Ekstrand, Intel
-
Jesse Hall, Google
-
The VK_KHR_variable_pointers extension allows implementations to indicate
their level of support for the SPV_KHR_variable_pointers SPIR-V extension.
The SPIR-V extension allows shader modules to use invocation-private
pointers into uniform and/or storage buffers, where the pointer values can
be dynamic and non-uniform.
The SPV_KHR_variable_pointers extension introduces two capabilities.
The first, VariablePointersStorageBuffer, must be supported by all
implementations of this extension.
The second, VariablePointers, is optional.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTER_FEATURES_KHR
-
New Structures
New SPIR-V Capabilities
Promotion to Vulkan 1.1
All functionality in this extension is included in core Vulkan 1.1, with the
KHR suffix omitted, however support for the
variablePointersStorageBuffer feature is made optional.
The original type, enum and command names are still available as aliases of
the core functionality.
Issues
1) Do we need an optional property for the SPIR-V
VariablePointersStorageBuffer capability or should it be mandatory when
this extension is advertised?
RESOLVED: Add it as a distinct feature, but make support mandatory. Adding it as a feature makes the extension easier to include in a future core API version. In the extension, the feature is mandatory, so that presence of the extension guarantees some functionality. When included in a core API version, the feature would be optional.
2) Can support for these capabilities vary between shader stages?
RESOLVED: No, if the capability is supported in any stage it must be supported in all stages.
3) Should the capabilities be features or limits?
RESOLVED: Features, primarily for consistency with other similar extensions.
Version History
-
Revision 1, 2017-03-14 (Jesse Hall and John Kessenich)
-
Internal revisions
-
VK_KHR_wayland_surface
- Name String
-
VK_KHR_wayland_surface - Extension Type
-
Instance extension
- Registered Extension Number
-
7
- Revision
-
6
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_surface
-
- Contact
-
-
Jesse Hall @critsec,Ian Elliott @ianelliottus
-
- Last Modified Date
-
2015-11-28
- IP Status
-
No known IP claims.
- Contributors
-
-
Patrick Doane, Blizzard
-
Jason Ekstrand, Intel
-
Ian Elliott, LunarG
-
Courtney Goeltzenleuchter, LunarG
-
Jesse Hall, Google
-
James Jones, NVIDIA
-
Antoine Labour, Google
-
Jon Leech, Khronos
-
David Mao, AMD
-
Norbert Nopper, Freescale
-
Alon Or-bach, Samsung
-
Daniel Rakos, AMD
-
Graham Sellers, AMD
-
Ray Smith, ARM
-
Jeff Vigil, Qualcomm
-
Chia-I Wu, LunarG
-
The VK_KHR_wayland_surface extension is an instance extension.
It provides a mechanism to create a VkSurfaceKHR object (defined by
the VK_KHR_surface extension) that refers to a Wayland
wl_surface, as well as a query to determine support for rendering to a
Wayland compositor.
New Object Types
None
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_WAYLAND_SURFACE_CREATE_INFO_KHR
-
New Enums
None
New Structures
Issues
1) Does Wayland need a way to query for compatibility between a particular
physical device and a specific Wayland display? This would be a more general
query than vkGetPhysicalDeviceSurfaceSupportKHR: if the
Wayland-specific query returned VK_TRUE for a (VkPhysicalDevice,
struct wl_display*) pair, then the physical device could be assumed to
support presentation to any VkSurfaceKHR for surfaces on the display.
RESOLVED: Yes. vkGetPhysicalDeviceWaylandPresentationSupportKHR was added to address this issue.
2) Should we require surfaces created with vkCreateWaylandSurfaceKHR
to support the VK_PRESENT_MODE_MAILBOX_KHR present mode?
RESOLVED: Yes.
Wayland is an inherently mailbox window system and mailbox support is
required for some Wayland compositor interactions to work as expected.
While handling these interactions may be possible with
VK_PRESENT_MODE_FIFO_KHR, it is much more difficult to do without
deadlock and requiring all Wayland applications to be able to support
implementations which only support VK_PRESENT_MODE_FIFO_KHR would be
an onerous restriction on application developers.
Version History
-
Revision 1, 2015-09-23 (Jesse Hall)
-
Initial draft, based on the previous contents of VK_EXT_KHR_swapchain (later renamed VK_EXT_KHR_surface).
-
-
Revision 2, 2015-10-02 (James Jones)
-
Added vkGetPhysicalDeviceWaylandPresentationSupportKHR() to resolve issue #1.
-
Adjusted wording of issue #1 to match the agreed-upon solution.
-
Renamed "window" parameters to "surface" to match Wayland conventions.
-
-
Revision 3, 2015-10-26 (Ian Elliott)
-
Renamed from VK_EXT_KHR_wayland_surface to VK_KHR_wayland_surface.
-
-
Revision 4, 2015-11-03 (Daniel Rakos)
-
Added allocation callbacks to vkCreateWaylandSurfaceKHR.
-
-
Revision 5, 2015-11-28 (Daniel Rakos)
-
Updated the surface create function to take a pCreateInfo structure.
-
-
Revision 6, 2017-02-08 (Jason Ekstrand)
-
Added the requirement that implementations support
VK_PRESENT_MODE_MAILBOX_KHR. -
Added wording about interactions between vkQueuePresentKHR and the Wayland requests sent to the compositor.
-
VK_KHR_win32_keyed_mutex
- Name String
-
VK_KHR_win32_keyed_mutex - Extension Type
-
Device extension
- Registered Extension Number
-
76
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_external_memory_win32
-
- Contact
-
-
Carsten Rohde @crohde
-
- Last Modified Date
-
2016-10-21
- IP Status
-
No known IP claims.
- Contributors
-
-
James Jones, NVIDIA
-
Jeff Juliano, NVIDIA
-
Carsten Rohde, NVIDIA
-
Applications that wish to import Direct3D 11 memory objects into the Vulkan API may wish to use the native keyed mutex mechanism to synchronize access to the memory between Vulkan and Direct3D. This extension provides a way for an application to access the keyed mutex associated with an imported Vulkan memory object when submitting command buffers to a queue.
New Object Types
None.
New Enum Constants
-
VK_STRUCTURE_TYPE_WIN32_KEYED_MUTEX_ACQUIRE_RELEASE_INFO_KHR
New Enums
None.
New Structs
New Functions
None.
Issues
None.
VK_KHR_win32_surface
- Name String
-
VK_KHR_win32_surface - Extension Type
-
Instance extension
- Registered Extension Number
-
10
- Revision
-
6
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_surface
-
- Contact
-
-
Jesse Hall @critsec,Ian Elliott @ianelliottus
-
- Last Modified Date
-
2017-04-24
- IP Status
-
No known IP claims.
- Contributors
-
-
Patrick Doane, Blizzard
-
Jason Ekstrand, Intel
-
Ian Elliott, LunarG
-
Courtney Goeltzenleuchter, LunarG
-
Jesse Hall, Google
-
James Jones, NVIDIA
-
Antoine Labour, Google
-
Jon Leech, Khronos
-
David Mao, AMD
-
Norbert Nopper, Freescale
-
Alon Or-bach, Samsung
-
Daniel Rakos, AMD
-
Graham Sellers, AMD
-
Ray Smith, ARM
-
Jeff Vigil, Qualcomm
-
Chia-I Wu, LunarG
-
The VK_KHR_win32_surface extension is an instance extension.
It provides a mechanism to create a VkSurfaceKHR object (defined by
the VK_KHR_surface extension) that refers to a Win32 HWND, as
well as a query to determine support for rendering to the windows desktop.
New Object Types
None
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_WIN32_SURFACE_CREATE_INFO_KHR
-
New Enums
None
New Structures
Issues
1) Does Win32 need a way to query for compatibility between a particular physical device and a specific screen? Compatibility between a physical device and a window generally only depends on what screen the window is on. However, there is not an obvious way to identify a screen without already having a window on the screen.
RESOLVED: No. While it may be useful, there is not a clear way to do this on Win32. However, a method was added to query support for presenting to the windows desktop as a whole.
2) If a native window object (HWND) is used by one graphics API, and
then is later used by a different graphics API (one of which is Vulkan), can
these uses interfere with each other?
RESOLVED: Yes.
Uses of a window object by multiple graphics APIs results in undefined behavior. Such behavior may succeed when using one Vulkan implementation but fail when using a different Vulkan implementation. Potential failures include:
-
Creating then destroying a flip presentation model DXGI swapchain on a window object can prevent vkCreateSwapchainKHR from succeeding on the same window object.
-
Creating then destroying a VkSwapchainKHR on a window object can prevent creation of a bitblt model DXGI swapchain on the same window object.
-
Creating then destroying a VkSwapchainKHR on a window object can effectively
SetPixelFormatto a different format than the format chosen by an OpenGL application. -
Creating then destroying a VkSwapchainKHR on a window object on one VkPhysicalDevice can prevent vkCreateSwapchainKHR from succeeding on the same window object, but on a different VkPhysicalDevice that is associated with a different Vulkan ICD.
In all cases the problem can be worked around by creating a new window object.
Technical details include:
-
Creating a DXGI swapchain over a window object can alter the object for the remainder of its lifetime. The alteration persists even after the DXGI swapchain has been destroyed. This alteration can make it impossible for a conformant Vulkan implementation to create a VkSwapchainKHR over the same window object. Mention of this alteration can be found in the remarks section of the MSDN documentation for
DXGI_SWAP_EFFECT. -
Calling GDI’s
SetPixelFormat(needed by OpenGL’s WGL layer) on a window object alters the object for the remainder of its lifetime. The MSDN documentation forSetPixelFormatexplains that a window object’s pixel format can be set only one time. -
Creating a VkSwapchainKHR over a window object can alter the object for the remaining life of its lifetime. Either of the above alterations may occur as a side-effect of VkSwapchainKHR.
Version History
-
Revision 1, 2015-09-23 (Jesse Hall)
-
Initial draft, based on the previous contents of VK_EXT_KHR_swapchain (later renamed VK_EXT_KHR_surface).
-
-
Revision 2, 2015-10-02 (James Jones)
-
Added presentation support query for win32 desktops.
-
-
Revision 3, 2015-10-26 (Ian Elliott)
-
Renamed from VK_EXT_KHR_win32_surface to VK_KHR_win32_surface.
-
-
Revision 4, 2015-11-03 (Daniel Rakos)
-
Added allocation callbacks to vkCreateWin32SurfaceKHR.
-
-
Revision 5, 2015-11-28 (Daniel Rakos)
-
Updated the surface create function to take a pCreateInfo structure.
-
-
Revision 6, 2017-04-24 (Jeff Juliano)
-
Add issue 2 addressing reuse of a native window object in a different Graphics API, or by a different Vulkan ICD.
-
VK_KHR_xcb_surface
- Name String
-
VK_KHR_xcb_surface - Extension Type
-
Instance extension
- Registered Extension Number
-
6
- Revision
-
6
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_surface
-
- Contact
-
-
Jesse Hall @critsec,Ian Elliott @ianelliottus
-
- Last Modified Date
-
2015-11-28
- IP Status
-
No known IP claims.
- Contributors
-
-
Patrick Doane, Blizzard
-
Jason Ekstrand, Intel
-
Ian Elliott, LunarG
-
Courtney Goeltzenleuchter, LunarG
-
Jesse Hall, Google
-
James Jones, NVIDIA
-
Antoine Labour, Google
-
Jon Leech, Khronos
-
David Mao, AMD
-
Norbert Nopper, Freescale
-
Alon Or-bach, Samsung
-
Daniel Rakos, AMD
-
Graham Sellers, AMD
-
Ray Smith, ARM
-
Jeff Vigil, Qualcomm
-
Chia-I Wu, LunarG
-
The VK_KHR_xcb_surface extension is an instance extension.
It provides a mechanism to create a VkSurfaceKHR object (defined by
the VK_KHR_surface extension) that refers to an X11 Window, using
the XCB client-side library, as well as a query to determine support for
rendering via XCB.
New Object Types
None
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_XCB_SURFACE_CREATE_INFO_KHR
-
New Enums
None
New Structures
Issues
1) Does XCB need a way to query for compatibility between a particular
physical device and a specific screen? This would be a more general query
than vkGetPhysicalDeviceSurfaceSupportKHR: If it returned
VK_TRUE, then the physical device could be assumed to support
presentation to any window on that screen.
RESOLVED: Yes, this is needed for toolkits that want to create a VkDevice before creating a window. To ensure the query is reliable, it must be made against a particular X visual rather than the screen in general.
Version History
-
Revision 1, 2015-09-23 (Jesse Hall)
-
Initial draft, based on the previous contents of VK_EXT_KHR_swapchain (later renamed VK_EXT_KHR_surface).
-
-
Revision 2, 2015-10-02 (James Jones)
-
Added presentation support query for an (xcb_connection_t*, xcb_visualid_t) pair.
-
Removed "root" parameter from CreateXcbSurfaceKHR(), as it is redundant when a window on the same screen is specified as well.
-
Adjusted wording of issue #1 and added agreed upon resolution.
-
-
Revision 3, 2015-10-14 (Ian Elliott)
-
Removed "root" parameter from CreateXcbSurfaceKHR() in one more place.
-
-
Revision 4, 2015-10-26 (Ian Elliott)
-
Renamed from VK_EXT_KHR_xcb_surface to VK_KHR_xcb_surface.
-
-
Revision 5, 2015-10-23 (Daniel Rakos)
-
Added allocation callbacks to vkCreateXcbSurfaceKHR.
-
-
Revision 6, 2015-11-28 (Daniel Rakos)
-
Updated the surface create function to take a pCreateInfo structure.
-
VK_KHR_xlib_surface
- Name String
-
VK_KHR_xlib_surface - Extension Type
-
Instance extension
- Registered Extension Number
-
5
- Revision
-
6
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_surface
-
- Contact
-
-
Jesse Hall @critsec,Ian Elliott @ianelliottus
-
- Last Modified Date
-
2015-11-28
- IP Status
-
No known IP claims.
- Contributors
-
-
Patrick Doane, Blizzard
-
Jason Ekstrand, Intel
-
Ian Elliott, LunarG
-
Courtney Goeltzenleuchter, LunarG
-
Jesse Hall, Google
-
James Jones, NVIDIA
-
Antoine Labour, Google
-
Jon Leech, Khronos
-
David Mao, AMD
-
Norbert Nopper, Freescale
-
Alon Or-bach, Samsung
-
Daniel Rakos, AMD
-
Graham Sellers, AMD
-
Ray Smith, ARM
-
Jeff Vigil, Qualcomm
-
Chia-I Wu, LunarG
-
The VK_KHR_xlib_surface extension is an instance extension.
It provides a mechanism to create a VkSurfaceKHR object (defined by
the VK_KHR_surface extension) that refers to an X11 Window, using
the Xlib client-side library, as well as a query to determine support for
rendering via Xlib.
New Object Types
None
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_XLIB_SURFACE_CREATE_INFO_KHR
-
New Enums
None
New Structures
Issues
1) Does X11 need a way to query for compatibility between a particular
physical device and a specific screen? This would be a more general query
than vkGetPhysicalDeviceSurfaceSupportKHR : if it returned
VK_TRUE, then the physical device could be assumed to support
presentation to any window on that screen.
RESOLVED: Yes, this is needed for toolkits that want to create a VkDevice before creating a window. To ensure the query is reliable, it must be made against a particular X visual rather than the screen in general.
Version History
-
Revision 1, 2015-09-23 (Jesse Hall)
-
Initial draft, based on the previous contents of VK_EXT_KHR_swapchain (later renamed VK_EXT_KHR_surface).
-
-
Revision 2, 2015-10-02 (James Jones)
-
Added presentation support query for (Display*, VisualID) pair.
-
Removed "root" parameter from CreateXlibSurfaceKHR(), as it is redundant when a window on the same screen is specified as well.
-
Added appropriate X errors.
-
Adjusted wording of issue #1 and added agreed upon resolution.
-
-
Revision 3, 2015-10-14 (Ian Elliott)
-
Renamed this extension from VK_EXT_KHR_x11_surface to VK_EXT_KHR_xlib_surface.
-
-
Revision 4, 2015-10-26 (Ian Elliott)
-
Renamed from VK_EXT_KHR_xlib_surface to VK_KHR_xlib_surface.
-
-
Revision 5, 2015-11-03 (Daniel Rakos)
-
Added allocation callbacks to vkCreateXlibSurfaceKHR.
-
-
Revision 6, 2015-11-28 (Daniel Rakos)
-
Updated the surface create function to take a pCreateInfo structure.
-
VK_EXT_acquire_xlib_display
- Name String
-
VK_EXT_acquire_xlib_display - Extension Type
-
Instance extension
- Registered Extension Number
-
90
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_EXT_direct_mode_display
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2016-12-13
- IP Status
-
No known IP claims.
- Contributors
-
-
Dave Airlie, Red Hat
-
Pierre Boudier, NVIDIA
-
James Jones, NVIDIA
-
Damien Leone, NVIDIA
-
Pierre-Loup Griffais, Valve
-
Liam Middlebrook, NVIDIA
-
Daniel Vetter, Intel
-
This extension allows an application to take exclusive control on a display currently associated with an X11 screen. When control is acquired, the display will be deassociated from the X11 screen until control is released or the specified display connection is closed. Essentially, the X11 screen will behave as if the monitor has been unplugged until control is released.
New Enum Constants
None.
New Enums
None.
New Structures
None.
New Functions
Issues
1) Should vkAcquireXlibDisplayEXT take an RandR display ID, or a Vulkan display handle as input?
RESOLVED: A Vulkan display handle. Otherwise there would be no way to specify handles to displays that had been “blacklisted” or prevented from being included in the X11 display list by some native platform or vendor-specific mechanism.
2) How does an application figure out which RandR display corresponds to a Vulkan display?
RESOLVED: A new function, vkGetRandROutputDisplayEXT, is introduced for this purpose.
3) Should vkGetRandROutputDisplayEXT be part of this extension, or a general Vulkan + RandR or Vulkan + Xlib extension?
RESOLVED: To avoid yet another extension, include it in this extension.
Version History
-
Revision 1, 2016-12-13 (James Jones)
-
Initial draft
-
VK_EXT_blend_operation_advanced
- Name String
-
VK_EXT_blend_operation_advanced - Extension Type
-
Device extension
- Registered Extension Number
-
149
- Revision
-
2
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Jeff Bolz @jeffbolznv
-
- Last Modified Date
-
2017-06-12
- Contributors
-
-
Jeff Bolz, NVIDIA
-
This extension adds a number of “advanced” blending operations that can be used to perform new color blending operations, many of which are more complex than the standard blend modes provided by unextended Vulkan. This extension requires different styles of usage, depending on the level of hardware support and the enabled features:
-
If VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT::
advancedBlendCoherentOperationsisVK_FALSE, the new blending operations are supported, but a memory dependency must separate each advanced blend operation on a given sample.VK_ACCESS_COLOR_ATTACHMENT_READ_NONCOHERENT_BIT_EXTis used to synchronize reads using advanced blend operations. -
If VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT::
advancedBlendCoherentOperationsisVK_TRUE, advanced blend operations obey primitive order just like basic blend operations.
In unextended Vulkan, the set of blending operations is limited, and can be
expressed very simply.
The VK_BLEND_OP_MIN and VK_BLEND_OP_MAX blend operations simply
compute component-wise minimums or maximums of source and destination color
components.
The VK_BLEND_OP_ADD, VK_BLEND_OP_SUBTRACT, and
VK_BLEND_OP_REVERSE_SUBTRACT modes multiply the source and destination
colors by source and destination factors and either add the two products
together or subtract one from the other.
This limited set of operations supports many common blending operations but
precludes the use of more sophisticated transparency and blending operations
commonly available in many dedicated imaging APIs.
This extension provides a number of new “advanced” blending operations.
Unlike traditional blending operations using VK_BLEND_OP_ADD, these
blending equations do not use source and destination factors specified by
VkBlendFactor.
Instead, each blend operation specifies a complete equation based on the
source and destination colors.
These new blend operations are used for both RGB and alpha components; they
must not be used to perform separate RGB and alpha blending (via different
values of color and alpha VkBlendOp).
These blending operations are performed using premultiplied colors, where
RGB colors can be considered premultiplied or non-premultiplied by alpha,
according to the srcPremultiplied and dstPremultiplied members
of VkPipelineColorBlendAdvancedStateCreateInfoEXT.
If a color is considered non-premultiplied, the (R,G,B) color components are
multiplied by the alpha component prior to blending.
For non-premultiplied color components in the range [0,1], the
corresponding premultiplied color component would have values in the range
[0 × A, 1 × A].
Many of these advanced blending equations are formulated where the result of
blending source and destination colors with partial coverage have three
separate contributions: from the portions covered by both the source and the
destination, from the portion covered only by the source, and from the
portion covered only by the destination.
The blend parameter
VkPipelineColorBlendAdvancedStateCreateInfoEXT::blendOverlap
can be used to specify a correlation between source and destination pixel
coverage.
If set to VK_BLEND_OVERLAP_CONJOINT_EXT, the source and destination
are considered to have maximal overlap, as would be the case if drawing two
objects on top of each other.
If set to VK_BLEND_OVERLAP_DISJOINT_EXT, the source and destination
are considered to have minimal overlap, as would be the case when rendering
a complex polygon tessellated into individual non-intersecting triangles.
If set to VK_BLEND_OVERLAP_UNCORRELATED_EXT, the source and
destination coverage are assumed to have no spatial correlation within the
pixel.
In addition to the coherency issues on implementations not supporting
advancedBlendCoherentOperations, this extension has several
limitations worth noting.
First, the new blend operations have a limit on the number of color
attachments they can be used with, as indicated by
VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT::advancedBlendMaxColorAttachments.
Additionally, blending precision may be limited to 16-bit floating-point,
which may result in a loss of precision and dynamic range for framebuffer
formats with 32-bit floating-point components, and in a loss of precision
for formats with 12- and 16-bit signed or unsigned normalized integer
components.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BLEND_OPERATION_ADVANCED_FEATURES_EXT -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BLEND_OPERATION_ADVANCED_PROPERTIES_EXT -
VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_ADVANCED_STATE_CREATE_INFO_EXT
-
-
Extending VkAccessFlagBits:
-
VK_ACCESS_COLOR_ATTACHMENT_READ_NONCOHERENT_BIT_EXT
-
-
Extending VkBlendOp:
-
VK_BLEND_OP_ZERO_EXT -
VK_BLEND_OP_SRC_EXT -
VK_BLEND_OP_DST_EXT -
VK_BLEND_OP_SRC_OVER_EXT -
VK_BLEND_OP_DST_OVER_EXT -
VK_BLEND_OP_SRC_IN_EXT -
VK_BLEND_OP_DST_IN_EXT -
VK_BLEND_OP_SRC_OUT_EXT -
VK_BLEND_OP_DST_OUT_EXT -
VK_BLEND_OP_SRC_ATOP_EXT -
VK_BLEND_OP_DST_ATOP_EXT -
VK_BLEND_OP_XOR_EXT -
VK_BLEND_OP_MULTIPLY_EXT -
VK_BLEND_OP_SCREEN_EXT -
VK_BLEND_OP_OVERLAY_EXT -
VK_BLEND_OP_DARKEN_EXT -
VK_BLEND_OP_LIGHTEN_EXT -
VK_BLEND_OP_COLORDODGE_EXT -
VK_BLEND_OP_COLORBURN_EXT -
VK_BLEND_OP_HARDLIGHT_EXT -
VK_BLEND_OP_SOFTLIGHT_EXT -
VK_BLEND_OP_DIFFERENCE_EXT -
VK_BLEND_OP_EXCLUSION_EXT -
VK_BLEND_OP_INVERT_EXT -
VK_BLEND_OP_INVERT_RGB_EXT -
VK_BLEND_OP_LINEARDODGE_EXT -
VK_BLEND_OP_LINEARBURN_EXT -
VK_BLEND_OP_VIVIDLIGHT_EXT -
VK_BLEND_OP_LINEARLIGHT_EXT -
VK_BLEND_OP_PINLIGHT_EXT -
VK_BLEND_OP_HARDMIX_EXT -
VK_BLEND_OP_HSL_HUE_EXT -
VK_BLEND_OP_HSL_SATURATION_EXT -
VK_BLEND_OP_HSL_COLOR_EXT -
VK_BLEND_OP_HSL_LUMINOSITY_EXT -
VK_BLEND_OP_PLUS_EXT -
VK_BLEND_OP_PLUS_CLAMPED_EXT -
VK_BLEND_OP_PLUS_CLAMPED_ALPHA_EXT -
VK_BLEND_OP_PLUS_DARKER_EXT -
VK_BLEND_OP_MINUS_EXT -
VK_BLEND_OP_MINUS_CLAMPED_EXT -
VK_BLEND_OP_CONTRAST_EXT -
VK_BLEND_OP_INVERT_OVG_EXT -
VK_BLEND_OP_RED_EXT -
VK_BLEND_OP_GREEN_EXT -
VK_BLEND_OP_BLUE_EXT
-
New Enums
New Structures
New Functions
None.
Issues
None.
Version History
-
Revisions 1-2, 2017-06-12 (Jeff Bolz)
-
Internal revisions
-
VK_EXT_conservative_rasterization
- Name String
-
VK_EXT_conservative_rasterization - Extension Type
-
Device extension
- Registered Extension Number
-
102
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Piers Daniell @pdaniell-nv
-
- Last Modified Data
-
2017-08-28
- Contributors
-
-
Daniel Koch, NVIDIA
-
Daniel Rakos, AMD
-
Jeff Bolz, NVIDIA
-
Slawomir Grajewski, Intel
-
Stu Smith, Imagination Technologies
-
This extension adds a new rasterization mode called conservative rasterization. There are two modes of conservative rasterization; overestimation and underestimation.
When overestimation is enabled, if any part of the primitive, including its edges, covers any part of the rectangular pixel area, including its sides, then a fragment is generated with all coverage samples turned on. This extension allows for some variation in implementations by accounting for differences in overestimation, where the generating primitive size is increased at each of its edges by some sub-pixel amount to further increase conservative pixel coverage. Implementations can allow the application to specify an extra overestimation beyond the base overestimation the implementation already does. It also allows implementations to either cull degenerate primitives or rasterize them.
When underestimation is enabled, fragments are only generated if the rectangular pixel area is fully covered by the generating primitive. If supported by the implementation, when a pixel rectangle is fully covered the fragment shader input variable builtin called FullyCoveredEXT is set to true. The shader variable works in either overestimation or underestimation mode.
Implementations can process degenerate triangles and lines by either discarding them or generating conservative fragments for them. Degenerate triangles are those that end up with zero area after the rasterizer quantizes them to the fixed-point pixel grid. Degenerate lines are those with zero length after quantization.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_CONSERVATIVE_RASTERIZATION_PROPERTIES_EXT -
VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_CONSERVATIVE_STATE_CREATE_INFO_EXT
-
New Structures
New Functions
None.
Issues
None.
Version History
-
Revision 1, 2017-08-28 (Piers Daniell)
-
Internal revisions
-
VK_EXT_debug_marker
- Name String
-
VK_EXT_debug_marker - Extension Type
-
Device extension
- Registered Extension Number
-
23
- Revision
-
4
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_EXT_debug_report
-
- Contact
-
-
Baldur Karlsson @baldurk
-
- Last Modified Date
-
2017-01-31
- IP Status
-
No known IP claims.
- Contributors
-
-
Baldur Karlsson
-
Dan Ginsburg, Valve
-
Jon Ashburn, LunarG
-
Kyle Spagnoli, NVIDIA
-
The VK_EXT_debug_marker extension is a device extension.
It introduces concepts of object naming and tagging, for better tracking of
Vulkan objects, as well as additional commands for recording annotations of
named sections of a workload to aid organization and offline analysis in
external tools.
New Object Types
None
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_DEBUG_MARKER_OBJECT_NAME_INFO_EXT -
VK_STRUCTURE_TYPE_DEBUG_MARKER_OBJECT_TAG_INFO_EXT -
VK_STRUCTURE_TYPE_DEBUG_MARKER_MARKER_INFO_EXT
-
New Enums
None
New Structures
New Functions
Examples
Example 1
Associate a name with an image, for easier debugging in external tools or with validation layers that can print a friendly name when referring to objects in error messages.
extern VkDevice device;
extern VkImage image;
// Must call extension functions through a function pointer:
PFN_vkDebugMarkerSetObjectNameEXT pfnDebugMarkerSetObjectNameEXT = (PFN_vkDebugMarkerSetObjectNameEXT)vkGetDeviceProcAddr(device, "vkDebugMarkerSetObjectNameEXT");
// Set a name on the image
const VkDebugMarkerObjectNameInfoEXT imageNameInfo =
{
VK_STRUCTURE_TYPE_DEBUG_MARKER_OBJECT_NAME_INFO_EXT, // sType
NULL, // pNext
VK_DEBUG_REPORT_OBJECT_TYPE_IMAGE_EXT, // objectType
(uint64_t)image, // object
"Brick Diffuse Texture", // pObjectName
};
pfnDebugMarkerSetObjectNameEXT(device, &imageNameInfo);
// A subsequent error might print:
// Image 'Brick Diffuse Texture' (0xc0dec0dedeadbeef) is used in a
// command buffer with no memory bound to it.
Example 2
Annotating regions of a workload with naming information so that offline analysis tools can display a more usable visualisation of the commands submitted.
extern VkDevice device;
extern VkCommandBuffer commandBuffer;
// Must call extension functions through a function pointer:
PFN_vkCmdDebugMarkerBeginEXT pfnCmdDebugMarkerBeginEXT = (PFN_vkCmdDebugMarkerBeginEXT)vkGetDeviceProcAddr(device, "vkCmdDebugMarkerBeginEXT");
PFN_vkCmdDebugMarkerEndEXT pfnCmdDebugMarkerEndEXT = (PFN_vkCmdDebugMarkerEndEXT)vkGetDeviceProcAddr(device, "vkCmdDebugMarkerEndEXT");
PFN_vkCmdDebugMarkerInsertEXT pfnCmdDebugMarkerInsertEXT = (PFN_vkCmdDebugMarkerInsertEXT)vkGetDeviceProcAddr(device, "vkCmdDebugMarkerInsertEXT");
// Describe the area being rendered
const VkDebugMarkerMarkerInfoEXT houseMarker =
{
VK_STRUCTURE_TYPE_DEBUG_MARKER_MARKER_INFO_EXT, // sType
NULL, // pNext
"Brick House", // pMarkerName
{ 1.0f, 0.0f, 0.0f, 1.0f }, // color
};
// Start an annotated group of calls under the 'Brick House' name
pfnCmdDebugMarkerBeginEXT(commandBuffer, &houseMarker);
{
// A mutable structure for each part being rendered
VkDebugMarkerMarkerInfoEXT housePartMarker =
{
VK_STRUCTURE_TYPE_DEBUG_MARKER_MARKER_INFO_EXT, // sType
NULL, // pNext
NULL, // pMarkerName
{ 0.0f, 0.0f, 0.0f, 0.0f }, // color
};
// Set the name and insert the marker
housePartMarker.pMarkerName = "Walls";
pfnCmdDebugMarkerInsertEXT(commandBuffer, &housePartMarker);
// Insert the drawcall for the walls
vkCmdDrawIndexed(commandBuffer, 1000, 1, 0, 0, 0);
// Insert a recursive region for two sets of windows
housePartMarker.pMarkerName = "Windows";
pfnCmdDebugMarkerBeginEXT(commandBuffer, &housePartMarker);
{
vkCmdDrawIndexed(commandBuffer, 75, 6, 1000, 0, 0);
vkCmdDrawIndexed(commandBuffer, 100, 2, 1450, 0, 0);
}
pfnCmdDebugMarkerEndEXT(commandBuffer);
housePartMarker.pMarkerName = "Front Door";
pfnCmdDebugMarkerInsertEXT(commandBuffer, &housePartMarker);
vkCmdDrawIndexed(commandBuffer, 350, 1, 1650, 0, 0);
housePartMarker.pMarkerName = "Roof";
pfnCmdDebugMarkerInsertEXT(commandBuffer, &housePartMarker);
vkCmdDrawIndexed(commandBuffer, 500, 1, 2000, 0, 0);
}
// End the house annotation started above
pfnCmdDebugMarkerEndEXT(commandBuffer);
Issues
1) Should the tag or name for an object be specified using the pNext
parameter in the object’s Vk*CreateInfo structure?
RESOLVED: No.
While this fits with other Vulkan patterns and would allow more type safety
and future proofing against future objects, it has notable downsides.
In particular passing the name at Vk*CreateInfo time does not allow
renaming, prevents late binding of naming information, and does not allow
naming of implicitly created objects such as queues and swapchain images.
2) Should the command annotation functions vkCmdDebugMarkerBeginEXT and vkCmdDebugMarkerEndEXT support the ability to specify a color?
RESOLVED: Yes. The functions have been expanded to take an optional color which can be used at will by implementations consuming the command buffer annotations in their visualisation.
3) Should the functions added in this extension accept an extensible structure as their parameter for a more flexible API, as opposed to direct function parameters? If so, which functions?
RESOLVED: Yes.
All functions have been modified to take a structure type with extensible
pNext pointer, to allow future extensions to add additional annotation
information in the same commands.
Version History
-
Revision 1, 2016-02-24 (Baldur Karlsson)
-
Initial draft, based on LunarG marker spec
-
-
Revision 2, 2016-02-26 (Baldur Karlsson)
-
Renamed Dbg to DebugMarker in function names
-
Allow markers in secondary command buffers under certain circumstances
-
Minor language tweaks and edits
-
-
Revision 3, 2016-04-23 (Baldur Karlsson)
-
Reorganise spec layout to closer match desired organisation
-
Added optional color to markers (both regions and inserted labels)
-
Changed functions to take extensible structs instead of direct function parameters
-
-
Revision 4, 2017-01-31 (Baldur Karlsson)
-
Added explicit dependency on VK_EXT_debug_report
-
Moved definition of VkDebugReportObjectTypeEXT to debug report chapter.
-
Fixed typo in dates in revision history
-
VK_EXT_debug_report
- Name String
-
VK_EXT_debug_report - Extension Type
-
Instance extension
- Registered Extension Number
-
12
- Revision
-
9
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Courtney Goeltzenleuchter @courtney-g
-
- Last Modified Date
-
2017-09-12
- IP Status
-
No known IP claims.
- Contributors
-
-
Courtney Goeltzenleuchter, LunarG
-
Dan Ginsburg, Valve
-
Jon Ashburn, LunarG
-
Mark Lobodzinski, LunarG
-
Due to the nature of the Vulkan interface, there is very little error
information available to the developer and application.
By enabling optional validation layers and using the VK_EXT_debug_report
extension, developers can obtain much more detailed feedback on the
application’s use of Vulkan.
This extension defines a way for layers and the implementation to call back
to the application for events of interest to the application.
New Object Types
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_DEBUG_REPORT_CALLBACK_CREATE_INFO_EXT
-
-
Extending VkResult:
-
VK_ERROR_VALIDATION_FAILED_EXT
-
New Structures
New Functions
New Function Pointers
Examples
VK_EXT_debug_report allows an application to register multiple callbacks
with the validation layers.
Some callbacks may log the information to a file, others may cause a debug
break point or other application defined behavior.
An application can register callbacks even when no validation layers are
enabled, but they will only be called for loader and, if implemented, driver
events.
To capture events that occur while creating or destroying an instance an
application can link a VkDebugReportCallbackCreateInfoEXT structure
to the pNext element of the VkInstanceCreateInfo structure given
to vkCreateInstance.
This callback is only valid for the duration of the vkCreateInstance
and the vkDestroyInstance call.
Use vkCreateDebugReportCallbackEXT to create persistent callback
objects.
Example uses: Create three callback objects.
One will log errors and warnings to the debug console using Windows
OutputDebugString.
The second will cause the debugger to break at that callback when an error
happens and the third will log warnings to stdout.
VkResult res;
VkDebugReportCallbackEXT cb1, cb2, cb3;
VkDebugReportCallbackCreateInfoEXT callback1 = {
VK_STRUCTURE_TYPE_DEBUG_REPORT_CALLBACK_CREATE_INFO_EXT, // sType
NULL, // pNext
VK_DEBUG_REPORT_ERROR_BIT_EXT | // flags
VK_DEBUG_REPORT_WARNING_BIT_EXT,
myOutputDebugString, // pfnCallback
NULL // pUserData
};
res = vkCreateDebugReportCallbackEXT(instance, &callback1, &cb1);
if (res != VK_SUCCESS)
/* Do error handling for VK_ERROR_OUT_OF_MEMORY */
callback.flags = VK_DEBUG_REPORT_ERROR_BIT_EXT;
callback.pfnCallback = myDebugBreak;
callback.pUserData = NULL;
res = vkCreateDebugReportCallbackEXT(instance, &callback, &cb2);
if (res != VK_SUCCESS)
/* Do error handling for VK_ERROR_OUT_OF_MEMORY */
VkDebugReportCallbackCreateInfoEXT callback3 = {
VK_STRUCTURE_TYPE_DEBUG_REPORT_CALLBACK_CREATE_INFO_EXT, // sType
NULL, // pNext
VK_DEBUG_REPORT_WARNING_BIT_EXT, // flags
mystdOutLogger, // pfnCallback
NULL // pUserData
};
res = vkCreateDebugReportCallbackEXT(instance, &callback3, &cb3);
if (res != VK_SUCCESS)
/* Do error handling for VK_ERROR_OUT_OF_MEMORY */
...
/* remove callbacks when cleaning up */
vkDestroyDebugReportCallbackEXT(instance, cb1);
vkDestroyDebugReportCallbackEXT(instance, cb2);
vkDestroyDebugReportCallbackEXT(instance, cb3);
|
Note
In the initial release of the |
|
Note
In the initial release of the |
Issues
1) What is the hierarchy / seriousness of the message flags? E.g.
ERROR > WARN > PERF_WARN …
RESOLVED: There is no specific hierarchy. Each bit is independent and should be checked via bitwise AND. For example:
if (localFlags & VK_DEBUG_REPORT_ERROR_BIT_EXT) {
process error message
}
if (localFlags & VK_DEBUG_REPORT_DEBUG_BIT_EXT) {
process debug message
}
The validation layers do use them in a hierarchical way (ERROR >
WARN > PERF, WARN > DEBUG > INFO) and they (at
least at the time of this writing) only set one bit at a time.
But it is not a requirement of this extension.
It is possible that a layer may intercept and change, or augment the flags with extension values the application’s debug report handler may not be familiar with, so it is important to treat each flag independently.
2) Should there be a VU requiring
VkDebugReportCallbackCreateInfoEXT::flags to be non-zero?
RESOLVED: It may not be very useful, but we do not need VU statement
requiring the VkDebugReportCallbackCreateInfoEXT::msgFlags at
create-time to be non-zero.
One can imagine that apps may prefer it as it allows them to set the mask as
desired - including nothing - at runtime without having to check.
3) What is the difference between VK_DEBUG_REPORT_DEBUG_BIT_EXT and
VK_DEBUG_REPORT_INFORMATION_BIT_EXT?
RESOLVED: VK_DEBUG_REPORT_DEBUG_BIT_EXT specifies information that
could be useful debugging the Vulkan implementation itself.
Version History
-
Revision 1, 2015-05-20 (Courtney Goetzenleuchter)
-
Initial draft, based on LunarG KHR spec, other KHR specs
-
-
Revision 2, 2016-02-16 (Courtney Goetzenleuchter)
-
Update usage, documentation
-
-
Revision 3, 2016-06-14 (Courtney Goetzenleuchter)
-
Update VK_EXT_DEBUG_REPORT_SPEC_VERSION to indicate added support for vkCreateInstance and vkDestroyInstance
-
-
Revision 4, 2016-12-08 (Mark Lobodzinski)
-
Added Display_KHR, DisplayModeKHR extension objects
-
Added ObjectTable_NVX, IndirectCommandsLayout_NVX extension objects
-
Bumped spec revision
-
Retroactively added version history
-
-
Revision 5, 2017-01-31 (Baldur Karlsson)
-
Moved definition of VkDebugReportObjectTypeEXT from debug marker chapter
-
-
Revision 6, 2017-01-31 (Baldur Karlsson)
-
Added VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_KHR_EXT
-
-
Revision 7, 2017-04-20 (Courtney Goeltzenleuchter)
-
Clarify wording and address questions from developers.
-
-
Revision 8, 2017-04-21 (Courtney Goeltzenleuchter)
-
Remove unused enum VkDebugReportErrorEXT
-
-
Revision 9, 2017-09-12 (Tobias Hector)
-
Added interactions with Vulkan 1.1
-
VK_EXT_debug_utils
- Name String
-
VK_EXT_debug_utils - Extension Type
-
Instance extension
- Registered Extension Number
-
129
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Mark Young @marky-lunarg
-
- Last Modified Date
-
2017-09-14
- Revision
-
1
- IP Status
-
No known IP claims.
- Dependencies
-
-
This extension is written against version 1.0 of the Vulkan API.
-
Requires VkObjectType
-
- Contributors
-
-
Mark Young, LunarG
-
Baldur Karlsson
-
Ian Elliott, Google
-
Courtney Goeltzenleuchter, Google
-
Karl Schultz, LunarG
-
Mark Lobodzinski, LunarG
-
Mike Schuchardt, LunarG
-
Jaakko Konttinen, AMD
-
Dan Ginsburg, Valve Software
-
Rolando Olivares, Epic Games
-
Dan Baker, Oxide Games
-
Kyle Spagnoli, NVIDIA
-
Jon Ashburn, LunarG
-
Due to the nature of the Vulkan interface, there is very little error
information available to the developer and application.
By using the VK_EXT_debug_utils extension, developers can obtain more
information.
When combined with validation layers, even more detailed feedback on the
application’s use of Vulkan will be provided.
This extension provides the following capabilities:
-
The ability to create a debug messenger which will pass along debug messages to an application supplied callback.
-
The ability to identify specific Vulkan objects using a name or tag to improve tracking.
-
The ability to identify specific sections within a
VkQueueorVkCommandBufferusing labels to aid organization and offline analysis in external tools.
The main difference between this extension and VK_EXT_debug_report and
VK_EXT_debug_marker is that those extensions use
VkDebugReportObjectTypeEXT to identify objects.
This extension uses the core VkObjectType in place of
VkDebugReportObjectTypeEXT.
The primary reason for this move is that no future object type handle
enumeration values will be added to VkDebugReportObjectTypeEXT since
the creation of VkObjectType.
In addition, this extension combines the functionality of both
VK_EXT_debug_report and VK_EXT_debug_marker by allowing object
name and debug markers (now called labels) to be returned to the
application’s callback function.
This should assist in clarifying the details of a debug message including:
what objects are involved and potentially which location within a VkQueue or
VkCommandBuffer the message occurred.
New Object Types
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_DEBUG_UTILS_OBJECT_NAME_INFO_EXT -
VK_STRUCTURE_TYPE_DEBUG_UTILS_OBJECT_TAG_INFO_EXT -
VK_STRUCTURE_TYPE_DEBUG_UTILS_LABEL_EXT -
VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CALLBACK_DATA_EXT -
VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CREATE_INFO_EXT
-
-
Extending VkResult:
-
VK_ERROR_VALIDATION_FAILED_EXT
-
New Structures
New Functions
New Function Pointers
Examples
Example 1
VK_EXT_debug_utils allows an application to register multiple callbacks
with any Vulkan component wishing to report debug information.
Some callbacks may log the information to a file, others may cause a debug
break point or other application defined behavior.
An application can register callbacks even when no validation layers are
enabled, but they will only be called for loader and, if implemented, driver
events.
To capture events that occur while creating or destroying an instance an
application can link a VkDebugUtilsMessengerCreateInfoEXT structure
to the pNext element of the VkInstanceCreateInfo structure given
to vkCreateInstance.
This callback is only valid for the duration of the vkCreateInstance
and the vkDestroyInstance call.
Use vkCreateDebugUtilsMessengerEXT to create persistent callback
objects.
Example uses: Create three callback objects.
One will log errors and warnings to the debug console using Windows
OutputDebugString.
The second will cause the debugger to break at that callback when an error
happens and the third will log warnings to stdout.
extern VkInstance instance;
VkResult res;
VkDebugUtilsMessengerEXT cb1, cb2, cb3;
// Must call extension functions through a function pointer:
PFN_vkCreateDebugUtilsMessengerEXT pfnCreateDebugUtilsMessengerEXT = (PFN_vkCreateDebugUtilsMessengerEXT)vkGetDeviceProcAddr(device, "vkCreateDebugUtilsMessengerEXT");
PFN_vkDestroyDebugUtilsMessengerEXT pfnDestroyDebugUtilsMessengerEXT = (PFN_vkDestroyDebugUtilsMessengerEXT)vkGetDeviceProcAddr(device, "vkDestroyDebugUtilsMessengerEXT");
VkDebugUtilsMessengeCreateInfoEXT callback1 = {
VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CREATE_INFO_EXT, // sType
NULL, // pNext
0, // flags
VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT | // messageSeverity
VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT,
VK_DEBUG_UTILS_MESSAGE_TYPE_GENERAL_BIT_EXT | // messageType
VK_DEBUG_UTILS_MESSAGE_TYPE_VALIDATION_BIT_EXT,
myOutputDebugString, // pfnUserCallback
NULL // pUserData
};
res = pfnCreateDebugUtilsMessengerEXT(instance, &callback1, &cb1);
if (res != VK_SUCCESS) {
// Do error handling for VK_ERROR_OUT_OF_MEMORY
}
callback1.messageSeverity = VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT;
callback1.pfnCallback = myDebugBreak;
callback1.pUserData = NULL;
res = pfnCreateDebugUtilsMessengerEXT(instance, &callback1, &cb2);
if (res != VK_SUCCESS) {
// Do error handling for VK_ERROR_OUT_OF_MEMORY
}
VkDebugUtilsMessengerCreateInfoEXT callback3 = {
VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CREATE_INFO_EXT, // sType
NULL, // pNext
0, // flags
VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT, // messageSeverity
VK_DEBUG_UTILS_MESSAGE_TYPE_GENERAL_BIT_EXT | // messageType
VK_DEBUG_UTILS_MESSAGE_TYPE_VALIDATION_BIT_EXT,
mystdOutLogger, // pfnUserCallback
NULL // pUserData
};
res = pfnCreateDebugUtilsMessengerEXT(instance, &callback3, &cb3);
if (res != VK_SUCCESS) {
// Do error handling for VK_ERROR_OUT_OF_MEMORY
}
...
// Remove callbacks when cleaning up
pfnDestroyDebugUtilsMessengerEXT(instance, cb1);
pfnDestroyDebugUtilsMessengerEXT(instance, cb2);
pfnDestroyDebugUtilsMessengerEXT(instance, cb3);
Example 2
Associate a name with an image, for easier debugging in external tools or with validation layers that can print a friendly name when referring to objects in error messages.
extern VkDevice device;
extern VkImage image;
// Must call extension functions through a function pointer:
PFN_vkSetDebugUtilsObjectNameEXT pfnSetDebugUtilsObjectNameEXT = (PFN_vkSetDebugUtilsObjectNameEXT)vkGetDeviceProcAddr(device, "vkSetDebugUtilsObjectNameEXT");
// Set a name on the image
const VkDebugUtilsObjectNameInfoEXT imageNameInfo =
{
VK_STRUCTURE_TYPE_DEBUG_UTILS_OBJECT_NAME_INFO_EXT, // sType
NULL, // pNext
VK_OBJECT_TYPE_IMAGE, // objectType
(uint64_t)image, // object
"Brick Diffuse Texture", // pObjectName
};
pfnSetDebugUtilsObjectNameEXT(device, &imageNameInfo);
// A subsequent error might print:
// Image 'Brick Diffuse Texture' (0xc0dec0dedeadbeef) is used in a
// command buffer with no memory bound to it.
Example 3
Annotating regions of a workload with naming information so that offline analysis tools can display a more usable visualization of the commands submitted.
extern VkDevice device;
extern VkCommandBuffer commandBuffer;
// Must call extension functions through a function pointer:
PFN_vkQueueBeginDebugUtilsLabelEXT pfnQueueBeginDebugUtilsLabelEXT = (PFN_vkQueueBeginDebugUtilsLabelEXT)vkGetDeviceProcAddr(device, "vkQueueBeginDebugUtilsLabelEXT");
PFN_vkQueueEndDebugUtilsLabelEXT pfnQueueEndDebugUtilsLabelEXT = (PFN_vkQueueEndDebugUtilsLabelEXT)vkGetDeviceProcAddr(device, "vkQueueEndDebugUtilsLabelEXT");
PFN_vkCmdBeginDebugUtilsLabelEXT pfnCmdBeginDebugUtilsLabelEXT = (PFN_vkCmdBeginDebugUtilsLabelEXT)vkGetDeviceProcAddr(device, "vkCmdBeginDebugUtilsLabelEXT");
PFN_vkCmdEndDebugUtilsLabelEXT pfnCmdEndDebugUtilsLabelEXT = (PFN_vkCmdEndDebugUtilsLabelEXT)vkGetDeviceProcAddr(device, "vkCmdEndDebugUtilsLabelEXT");
PFN_vkCmdInsertDebugUtilsLabelEXT pfnCmdInsertDebugUtilsLabelEXT = (PFN_vkCmdInsertDebugUtilsLabelEXT)vkGetDeviceProcAddr(device, "vkCmdInsertDebugUtilsLabelEXT");
// Describe the area being rendered
const VkDebugUtilsLabelEXT houseLabel =
{
VK_STRUCTURE_TYPE_DEBUG_UTILS_LABEL_EXT, // sType
NULL, // pNext
"Brick House", // pLabelName
{ 1.0f, 0.0f, 0.0f, 1.0f }, // color
};
// Start an annotated group of calls under the 'Brick House' name
pfnCmdBeginDebugUtilsLabelEXT(commandBuffer, &houseLabel);
{
// A mutable structure for each part being rendered
VkDebugUtilsLabelEXT housePartLabel =
{
VK_STRUCTURE_TYPE_DEBUG_UTILS_LABEL_EXT, // sType
NULL, // pNext
NULL, // pLabelName
{ 0.0f, 0.0f, 0.0f, 0.0f }, // color
};
// Set the name and insert the marker
housePartLabel.pLabelName = "Walls";
pfnCmdInsertDebugUtilsLabelEXT(commandBuffer, &housePartLabel);
// Insert the drawcall for the walls
vkCmdDrawIndexed(commandBuffer, 1000, 1, 0, 0, 0);
// Insert a recursive region for two sets of windows
housePartLabel.pLabelName = "Windows";
pfnCmdBeginDebugUtilsLabelEXT(commandBuffer, &housePartLabel);
{
vkCmdDrawIndexed(commandBuffer, 75, 6, 1000, 0, 0);
vkCmdDrawIndexed(commandBuffer, 100, 2, 1450, 0, 0);
}
pfnCmdEndDebugUtilsLabelEXT(commandBuffer);
housePartLabel.pLabelName = "Front Door";
pfnCmdInsertDebugUtilsLabelEXT(commandBuffer, &housePartLabel);
vkCmdDrawIndexed(commandBuffer, 350, 1, 1650, 0, 0);
housePartLabel.pLabelName = "Roof";
pfnCmdInsertDebugUtilsLabelEXT(commandBuffer, &housePartLabel);
vkCmdDrawIndexed(commandBuffer, 500, 1, 2000, 0, 0);
}
// End the house annotation started above
pfnCmdEndDebugUtilsLabelEXT(commandBuffer);
// Do other work
vkEndCommandBuffer(commandBuffer);
// Describe the queue being used
const VkDebugUtilsLabelEXT queueLabel =
{
VK_STRUCTURE_TYPE_DEBUG_UTILS_LABEL_EXT, // sType
NULL, // pNext
"Main Render Work", // pLabelName
{ 0.0f, 1.0f, 0.0f, 1.0f }, // color
};
// Identify the queue label region
pfnQueueBeginDebugUtilsLabelEXT(queue, &queueLabel);
// Submit the work for the main render thread
const VkCommandBuffer cmd_bufs[] = {commandBuffer};
VkSubmitInfo submit_info = {.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO,
.pNext = NULL,
.waitSemaphoreCount = 0,
.pWaitSemaphores = NULL,
.pWaitDstStageMask = NULL,
.commandBufferCount = 1,
.pCommandBuffers = cmd_bufs,
.signalSemaphoreCount = 0,
.pSignalSemaphores = NULL};
vkQueueSubmit(queue, 1, &submit_info, fence);
// End the queue label region
pfnQueueEndDebugUtilsLabelEXT(queue);
Issues
1) Should we just name this extension VK_EXT_debug_report2
RESOLVED: No. There is enough additional changes to the structures to break backwards compatibility. So, a new name was decided that would not indicate any interaction with the previous extension.
2) Will validation layers immediately support all the new features.
RESOLVED: Not immediately. As one can imagine, there is a lot of work involved with converting the validation layer logging over to the new functionality. Basic logging, as seen in the origin VK_EXT_debug_report extension will be made available immediately. However, adding the labels and object names will take time. Since the priority for Khronos at this time is to continue focusing on Valid Usage statements, it may take a while before the new functionality is fully exposed.
3) If the validation layers won’t expose the new functionality immediately, then what’s the point of this extension?
RESOLVED: We needed a replacement for VK_EXT_debug_report because the VkDebugReportObjectTypeEXT enumeration will no longer be updated and any new objects will need to be debugged using the new functionality provided by this extension.
4) Should this extension be split into two separate parts (1 extension that is an instance extension providing the callback functionality, and another device extension providing the general debug marker and annotation functionality)?
RESOLVED: No, the functionality for this extension is too closely related. If we did split up the extension, where would the structures and enums live, and how would you define that the device behavior in the instance extension is really only valid if the device extension is enabled, and the functionality is passed in. It’s cleaner to just define this all as an instance extension, plus it allows the application to enable all debug functionality provided with one enable string during vkCreateInstance.
Version History
-
Revision 1, 2017-09-14 (Mark Young and all listed Contributors)
-
Initial draft, based on VK_EXT_debug_report and VK_EXT_debug_marker in addition to previous feedback supplied from various companies including Valve, Epic, and Oxide games.
-
VK_EXT_depth_range_unrestricted
- Name String
-
VK_EXT_depth_range_unrestricted - Extension Type
-
Device extension
- Registered Extension Number
-
14
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Piers Daniell @pdaniell-nv
-
- Last Modified Date
-
2017-06-22
- Contributors
-
-
Daniel Koch, NVIDIA
-
Jeff Bolz, NVIDIA
-
This extension removes the VkViewport minDepth and
maxDepth restrictions that the values must be between 0.0 and 1.0,
inclusive.
It also removes the same restriction on
VkPipelineDepthStencilStateCreateInfo minDepthBounds and
maxDepthBounds.
Finally it removes the restriction on the depth value in
VkClearDepthStencilValue.
New Object Types
None.
New Enum Constants
None.
New Enums
None.
New Structures
None.
New Functions
None.
Issues
1) How do VkViewport minDepth and maxDepth values outside
of the 0.0 to 1.0 range interact with
Primitive Clipping?
RESOLVED: The behavior described in Primitive
Clipping still applies.
If depth clamping is disabled the depth values are still clipped to 0
≤ zc ≤ wc before the viewport transform.
If depth clamping is enabled the above equation is ignored and the depth
values are instead clamped to the VkViewport minDepth and
maxDepth values, which in the case of this extension can be outside of
the 0.0 to 1.0 range.
2) What happens if a resulting depth fragment is outside of the 0.0 to
1.0 range and the depth buffer is fixed-point rather than floating-point?
RESOLVED: The supported range of a fixed-point depth buffer is 0.0 to
1.0 and depth fragments are clamped to this range.
Version History
-
Revision 1, 2017-06-22 (Piers Daniell)
-
Internal revisions
-
VK_EXT_descriptor_indexing
- Name String
-
VK_EXT_descriptor_indexing - Extension Type
-
Device extension
- Registered Extension Number
-
162
- Revision
-
2
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_maintenance3
-
- Contact
-
-
Jeff Bolz @jeffbolznv
-
- Status
-
Complete
- Last Modified Data
-
2017-10-02
- Contributors
-
-
Jeff Bolz, NVIDIA
-
Daniel Rakos, AMD
-
Slawomir Grajewski, Intel
-
Tobias Hector, Imagination Technologies
-
This extension adds several small features which together enable
applications to create large descriptor sets containing substantially all of
their resources, and selecting amongst those resources with dynamic
(non-uniform) indexes in the shader.
There are feature enables and SPIR-V capabilities for non-uniform descriptor
indexing in the shader, and non-uniform indexing in the shader requires use
of a new NonUniformEXT decoration defined in the
SPV_EXT_descriptor_indexing SPIR-V extension.
There are descriptor set layout binding creation flags enabling several
features:
-
Descriptors can be updated after they are bound to a command buffer, such that the execution of the command buffer reflects the most recent update to the descriptors.
-
Descriptors that are not used by any pending command buffers can be updated, which enables writing new descriptors for frame N+1 while frame N is executing.
-
Relax the requirement that all descriptors in a binding that is "statically used" must be valid, such that descriptors that are not accessed by a submission need not be valid and can be updated while that submission is executing.
-
The final binding in a descriptor set layout can have a variable size (and unsized arrays of resources are allowed in the GL_EXT_nonuniform_qualifier and SPV_EXT_descriptor_indexing extensions).
Note that it is valid for multiple descriptor arrays in a shader to use the same set and binding number, as long as they are all compatible with the descriptor type in the pipeline layout. This means a single array binding in the descriptor set can serve multiple texture dimensionalities, or an array of buffer descriptors can be used with multiple different block layouts.
There are new descriptor set layout and descriptor pool creation flags that
are required to opt in to the update-after-bind functionality, and there are
separate maxPerStage* and maxDescriptorSet* limits that apply to
these descriptor set layouts which may be much higher than the pre-existing
limits.
The old limits only count descriptors in non-updateAfterBind descriptor set
layouts, and the new limits count descriptors in all descriptor set layouts
in the pipeline layout.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_BINDING_FLAGS_CREATE_INFO_EXT -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_FEATURES_EXT -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_PROPERTIES_EXT -
VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_ALLOCATE_INFO_EXT -
VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_LAYOUT_SUPPORT_EXT
-
-
Extending VkDescriptorPoolCreateFlagBits:
-
VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT_EXT
-
-
Extending VkDescriptorSetLayoutCreateFlagBits:
-
VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXT
-
-
Extending VkResult:
-
VK_ERROR_FRAGMENTATION_EXT
-
New Enums
New Structures
New Functions
None.
Issues
None.
Version History
-
Revision 1, 2017-07-26 (Jeff Bolz)
-
Internal revisions
-
VK_EXT_direct_mode_display
- Name String
-
VK_EXT_direct_mode_display - Extension Type
-
Instance extension
- Registered Extension Number
-
89
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_display
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2016-12-13
- IP Status
-
No known IP claims.
- Contributors
-
-
Pierre Boudier, NVIDIA
-
James Jones, NVIDIA
-
Damien Leone, NVIDIA
-
Pierre-Loup Griffais, Valve
-
Liam Middlebrook, NVIDIA
-
This is extension, along with related platform exentions, allows applications to take exclusive control of displays associated with a native windowing system. This is especially useful for virtual reality applications that wish to hide HMDs (head mounted displays) from the native platform’s display management system, desktop, and/or other applications.
New Enum Constants
None.
New Enums
None.
New Structures
None.
New Functions
Issues
1) Should this extension and its related platform-specific extensions
leverage VK_KHR_display, or provide separate equivalent interfaces.
RESOLVED: Use VK_KHR_display concepts and objects.
VK_KHR_display can be used to enumerate all displays on the system,
including those attached to/in use by a window system or native platform,
but VK_KHR_display_swapchain will fail to create a swapchain on in-use
displays.
This extension and its platform-specific children will allow applications to
grab in-use displays away from window systems and/or native platforms,
allowing them to be used with VK_KHR_display_swapchain.
2) Are separate calls needed to acquire displays and enable direct mode?
RESOLVED: No, these operations happen in one combined command. Acquiring a display puts it into direct mode.
Version History
-
Revision 1, 2016-12-13 (James Jones)
-
Initial draft
-
VK_EXT_discard_rectangles
- Name String
-
VK_EXT_discard_rectangles - Extension Type
-
Device extension
- Registered Extension Number
-
100
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Piers Daniell @pdaniell-nv
-
- Last Modified Date
-
2016-12-22
- Interactions and External Dependencies
-
-
Interacts with VK_KHR_device_group
-
Interacts with Vulkan 1.1
-
- Contributors
-
-
Daniel Koch, NVIDIA
-
Jeff Bolz, NVIDIA
-
This extension provides additional orthogonally aligned “discard rectangles” specified in framebuffer-space coordinates that restrict rasterization of all points, lines and triangles.
From zero to an implementation-dependent limit (specified by
maxDiscardRectangles) number of discard rectangles can be operational
at once.
When one or more discard rectangles are active, rasterized fragments can
either survive if the fragment is within any of the operational discard
rectangles (VK_DISCARD_RECTANGLE_MODE_INCLUSIVE_EXT mode) or be
rejected if the fragment is within any of the operational discard rectangles
(VK_DISCARD_RECTANGLE_MODE_EXCLUSIVE_EXT mode).
These discard rectangles operate orthogonally to the existing scissor test functionality. The discard rectangles can be different for each physical device in a device group by specifying the device mask and setting discard rectangle dynamic state.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DISCARD_RECTANGLE_PROPERTIES_EXT -
VK_STRUCTURE_TYPE_PIPELINE_DISCARD_RECTANGLE_STATE_CREATE_INFO_EXT
-
-
Extending VkDynamicState
-
VK_DYNAMIC_STATE_DISCARD_RECTANGLE_EXT
-
New Structures
New Functions
Issues
None.
Version History
-
Revision 1, 2016-12-22 (Piers Daniell)
-
Internal revisions
-
VK_EXT_display_control
- Name String
-
VK_EXT_display_control - Extension Type
-
Device extension
- Registered Extension Number
-
92
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_EXT_display_surface_counter -
Requires
VK_KHR_swapchain
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2016-12-13
- IP Status
-
No known IP claims.
- Contributors
-
-
Pierre Boudier, NVIDIA
-
James Jones, NVIDIA
-
Damien Leone, NVIDIA
-
Pierre-Loup Griffais, Valve
-
Daniel Vetter, Intel
-
This extension defines a set of utility functions for use with the
VK_KHR_display and VK_KHR_display_swapchain extensions.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_DISPLAY_POWER_INFO_EXT -
VK_STRUCTURE_TYPE_DEVICE_EVENT_INFO_EXT -
VK_STRUCTURE_TYPE_DISPLAY_EVENT_INFO_EXT -
VK_STRUCTURE_TYPE_SWAPCHAIN_COUNTER_CREATE_INFO_EXT
-
New Structures
New Functions
Issues
1) Should this extension add an explicit “WaitForVsync” API or a fence signaled at vsync that the application can wait on?
RESOLVED: A fence. A separate API could later be provided that allows exporting the fence to a native object that could be inserted into standard run loops on POSIX and Windows systems.
2) Should callbacks be added for a vsync event, or in general to monitor events in Vulkan?
RESOLVED: No, fences should be used. Some events are generated by interrupts which are managed in the kernel. In order to use a callback provided by the application, drivers would need to have the userspace driver spawn threads that would wait on the kernel event, and hence the callbacks could be difficult for the application to synchronize with its other work given they would arrive on a foreign thread.
3) Should vblank or scanline events be exposed?
RESOLVED: Vblank events. Scanline events could be added by a separate extension, but the latency of processing an interrupt and waking up a userspace event is high enough that the accuracy of a scanline event would be rather low. Further, per-scanline interrupts are not supported by all hardware.
Version History
-
Revision 1, 2016-12-13 (James Jones)
-
Initial draft
-
VK_EXT_display_surface_counter
- Name String
-
VK_EXT_display_surface_counter - Extension Type
-
Instance extension
- Registered Extension Number
-
91
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_display
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2016-12-13
- IP Status
-
No known IP claims.
- Contributors
-
-
Pierre Boudier, NVIDIA
-
James Jones, NVIDIA
-
Damien Leone, NVIDIA
-
Pierre-Loup Griffais, Valve
-
Daniel Vetter, Intel
-
This is extension defines a vertical blanking period counter associated with display surfaces. It provides a mechanism to query support for such a counter from a VkSurfaceKHR object.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_SURFACE_CAPABILITIES_2_EXT
-
New Structures
New Functions
Issues
None.
Version History
-
Revision 1, 2016-12-13 (James Jones)
-
Initial draft
-
VK_EXT_external_memory_dma_buf
- Name String
-
VK_EXT_external_memory_dma_buf - Extension Type
-
Device extension
- Registered Extension Number
-
126
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_external_memory_fd
-
- Contact
-
-
Chad Versace @chadversary
-
- Last Modified Date
-
2017-10-10
- IP Status
-
No known IP claims.
- Contributors
-
-
Chad Versace, Google
-
James Jones, NVIDIA
-
Jason Ekstrand, Intel
-
A dma_buf is a type of file descriptor, defined by the Linux kernel, that allows sharing memory across kernel device drivers and across processes. This extension enables applications to import a dma_buf as VkDeviceMemory; to export VkDeviceMemory as a dma_buf; and to create VkBuffer objects that can be bound to that memory.
New Enum Constants
-
Extending VkExternalMemoryHandleTypeFlagBitsKHR:
-
VK_EXTERNAL_MEMORY_HANDLE_TYPE_DMA_BUF_BIT_EXT
-
Issues
1. How does the application, when creating a VkImage that it intends to bind to dma_buf VkDeviceMemory that contains an externally produced image, specify the memory layout (such as row pitch and DRM format modifier) of the VkImage? In other words, how does the application achieve behavior comparable to that provided by EGL_EXT_image_dma_buf_import and EGL_EXT_image_dma_buf_import_modifiers?
+
RESOLVED. Features comparable to those in EGL_EXT_image_dma_buf_import and EGL_EXT_image_dma_buf_import_modifiers will be provided by an extension layered atop this one.
2. Without the ability to specify the memory layout of external dma_buf images, how is this extension useful?
+
RESOLVED.
This extension provides exactly one new feature: the ability to
import/export between dma_bufs and VkDeviceMemory.
This feature, together with features provided by
VK_KHR_external_memory_fd, is sufficient to bind a VkBuffer to
dma_buf.
Version History
-
Revision 1, 2017-10-10 (Chad Versace)
-
Squashed internal revisions
-
VK_EXT_external_memory_host
- Name String
-
VK_EXT_external_memory_host - Extension Type
-
Device extension
- Registered Extension Number
-
179
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_external_memory
-
- Contact
-
-
Daniel Rakos @drakos-amd
-
- Last Modified Date
-
2017-11-10
- IP Status
-
No known IP claims.
- Contributors
-
-
Jaakko Konttinen, AMD
-
David Mao, AMD
-
Daniel Rakos, AMD
-
Tobias Hector, Imagination Technologies
-
Jason Ekstrand, Intel
-
James Jones, NVIDIA
-
This extension enables an application to import host allocations and host mapped foreign device memory to Vulkan memory objects.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_IMPORT_MEMORY_HOST_POINTER_INFO_EXT -
VK_STRUCTURE_TYPE_MEMORY_HOST_POINTER_PROPERTIES_EXT -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_MEMORY_HOST_PROPERTIES_EXT
-
-
Extending VkExternalMemoryHandleTypeFlagBitsKHR:
-
VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_ALLOCATION_BIT_EXT -
VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_MAPPED_FOREIGN_MEMORY_BIT_EXT
-
New Enums
None.
New Structs
New Functions
Issues
1) What memory type has to be used to import host pointers?
RESOLVED: Depends on the implementation. Applications have to use the new vkGetMemoryHostPointerPropertiesEXT command to query the supported memory types for a particular host pointer. The reported memory types may include memory types that come from a memory heap that is otherwise not usable for regular memory object allocation and thus such a heap’s size may be zero.
2) Can the application still access the contents of the host allocation after importing?
RESOLVED: Yes. However, usual synchronization requirements apply.
3) Can the application free the host allocation?
RESOLVED: No, it violates valid usage conditions. Using the memory object imported from a host allocation that’s already freed thus results in undefined behavior.
4) Is vkMapMemory expected to return the same host address which was specified when importing it to the memory object?
RESOLVED: No. Implementations are allowed to return the same address but it’s not required. Some implementations might return a different virtual mapping of the allocation, although the same physical pages will be used.
5) Is there any limitation on the alignment of the host pointer and/or size?
RESOLVED: Yes.
Both the address and the size have to be an integer multiple of
minImportedHostPointerAlignment.
In addition, some platforms and foreign devices may have additional
restrictions.
6) Can the same host allocation be imported multiple times into a given physical device?
RESOLVED: No, at least not guaranteed by this extension. Some platforms do not allow locking the same physical pages for device access multiple times, so attempting to do it may result in undefined behavior.
7) Does this extension support exporting the new handle type?
RESOLVED: No.
8) Should we include the possibility to import host mapped foreign device memory using this API?
RESOLVED: Yes, through a separate handle type. Implementations are still allowed to support only one of the handle types introduced by this extension by not returning import support for a particular handle type as returned in VkExternalMemoryPropertiesKHR.
Version History
-
Revision 1, 2017-11-10 (Daniel Rakos)
-
Internal revisions
-
VK_EXT_global_priority
- Name String
-
VK_EXT_global_priority - Extension Type
-
Device extension
- Registered Extension Number
-
175
- Revision
-
2
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Andres Rodriguez @lostgoat
-
- Last Modified Date
-
2017-10-06
- IP Status
-
No known IP claims.
- Contributors
-
-
Andres Rodriguez, Valve
-
Pierre-Loup Griffais, Valve
-
Dan Ginsburg, Valve
-
Mitch Singer, AMD
-
In Vulkan, users can specify device-scope queue priorities.
In some cases it may be useful to extend this concept to a system-wide
scope.
This extension provides a mechanism for caller’s to set their system-wide
priority.
The default queue priority is VK_QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT.
The driver implementation will attempt to skew hardware resource allocation in favour of the higher-priority task. Therefore, higher-priority work may retain similar latency and throughput characteristics even if the system is congested with lower priority work.
The global priority level of a queue shall take predence over the
per-process queue priority
(VkDeviceQueueCreateInfo::pQueuePriorities).
Abuse of this feature may result in starving the rest of the system from
hardware resources.
Therefore, the driver implementation may deny requests to acquire a priority
above the default priority (VK_QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT) if
the caller does not have sufficient privileges.
In this scenario VK_ERROR_NOT_PERMITTED_EXT is returned.
The driver implementation may fail the queue allocation request if resources
required to complete the operation have been exhausted (either by the same
process or a different process).
In this scenario VK_ERROR_INITIALIZATION_FAILED is returned.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_DEVICE_QUEUE_GLOBAL_PRIORITY_CREATE_INFO_EXT
-
-
Extending VkResult:
-
VK_ERROR_NOT_PERMITTED_EXT
-
New Enums
New Structures
New Functions
None.
Issues
None.
Version History
-
Revision 2, 2017-11-03 (Andres Rodriguez)
-
Fixed VkQueueGlobalPriorityEXT missing _EXT suffix
-
-
Revision 1, 2017-10-06 (Andres Rodriguez)
-
First version.
-
VK_EXT_hdr_metadata
- Name String
-
VK_EXT_hdr_metadata - Extension Type
-
Device extension
- Registered Extension Number
-
106
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_swapchain
-
- Contact
-
-
Courtney Goeltzenleuchter @courtney-g
-
- Last Modified Date
-
2017-03-04
- IP Status
-
No known IP claims.
- Contributors
-
-
Courtney Goeltzenleuchter, Google
-
This extension defines two new structures and a function to assign SMPTE
(the Society of Motion Picture and Television Engineers) 2086 metadata and
CTA (Consumer Technology Assocation) 861.3 metadata to a swapchain.
The metadata includes the color primaries, white point, and luminance range
of the mastering display, which all together define the color volume that
contains all the possible colors the mastering display can produce.
The mastering display is the display where creative work is done and
creative intent is established.
To preserve such creative intent as much as possible and achieve consistent
color reproduction on different viewing displays, it is useful for the
display pipeline to know the color volume of the original mastering display
where content was created or tuned.
This avoids performing unnecessary mapping of colors that are not
displayable on the original mastering display.
The metadata also includes the maxContentLightLevel and
maxFrameAverageLightLevel as defined by CTA 861.3.
While the general purpose of the metadata is to assist in the transformation between different color volumes of different displays and help achieve better color reproduction, it is not in the scope of this extension to define how exactly the metadata should be used in such a process. It is up to the implementation to determine how to make use of the metadata.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_HDR_METADATA_EXT
-
New Structures
New Functions
Issues
1) Do we need a query function?
PROPOSED: No, Vulkan does not provide queries for state that the application can track on its own.
2) Should we specify default if not specified by the application?
PROPOSED: No, that leaves the default up to the display.
Version History
-
Revision 1, 2016-12-27 (Courtney Goeltzenleuchter)
-
Initial version
-
VK_EXT_post_depth_coverage
- Name String
-
VK_EXT_post_depth_coverage - Extension Type
-
Device extension
- Registered Extension Number
-
156
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Daniel Koch @dgkoch
-
- Last Modified Date
-
2017-07-17
- Interactions and External Dependencies
-
-
This extension requires the SPV_KHR_post_depth_coverage SPIR-V extension.
-
This extension requires GL_ARB_post_depth_coverage or GL_EXT_post_depth_coverage for GLSL-based source languages.
-
- Contributors
-
-
Jeff Bolz, NVIDIA
-
This extension adds support for the following SPIR-V extension in Vulkan:
-
SPV_KHR_post_depth_coverage
which allows the fragment shader to control whether values in the
SampleMask built-in input variable reflect the coverage after the
early per-fragment depth and stencil tests are applied.
This extension adds a new PostDepthCoverage execution mode under the
SampleMaskPostDepthCoverage capability.
When this mode is specified along with EarlyFragmentTests, the value of
an input variable decorated with the
SampleMask built-in
reflects the coverage after the early fragment
tests are applied.
Otherwise, it reflects the coverage before the depth and stencil tests.
When using GLSL source-based shading languages, the post_depth_coverage
layout qualifier from GL_ARB_post_depth_coverage or
GL_EXT_post_depth_coverage maps to the PostDepthCoverage execution
mode.
New Object Types
None.
New Enum Constants
None.
New Enums
None.
New Structures
None.
New Functions
None.
New Built-In Variables
None.
New Variable Decoration
None.
New SPIR-V Capabilities
Issues
None yet.
Version History
-
Revision 1, 2017-07-17 (Daniel Koch)
-
Internal revisions
-
VK_EXT_queue_family_foreign
- Name String
-
VK_EXT_queue_family_foreign - Extension Type
-
Device extension
- Registered Extension Number
-
127
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_external_memory
-
- Contact
-
-
Chad Versace @chadversary
-
- Last Modified Date
-
2017-11-01
- IP Status
-
No known IP claims.
- Contributors
-
-
Chad Versace, Google
-
James Jones, NVIDIA
-
Jason Ekstrand, Intel
-
Jesse Hall, Google
-
Daniel Rakos, AMD
-
Ray Smith, ARM
-
This extension defines a special queue family,
VK_QUEUE_FAMILY_FOREIGN_EXT, which can be used to transfer ownership
of resources backed by external memory to foreign, external queues.
This is similar to VK_QUEUE_FAMILY_EXTERNAL_KHR, defined in
VK_KHR_external_memory.
The key differences between the two are:
-
The queues represented by
VK_QUEUE_FAMILY_EXTERNAL_KHRmust share the same physical device and the same driver version as the current VkInstance.VK_QUEUE_FAMILY_FOREIGN_EXThas no such restrictions. It can represent devices and drivers from other vendors, and can even represent non-Vulkan-capable devices. -
All resources backed by external memory support
VK_QUEUE_FAMILY_EXTERNAL_KHR. Support forVK_QUEUE_FAMILY_FOREIGN_EXTis more restrictive. -
Applications should expect transitions to/from
VK_QUEUE_FAMILY_FOREIGN_EXTto be more expensive than transitions to/fromVK_QUEUE_FAMILY_EXTERNAL_KHR.
New Enum Constants
-
Special constants:
-
VK_QUEUE_FAMILY_FOREIGN_EXT
-
Version History
-
Revision 1, 2017-11-01 (Chad Versace)
-
Squashed internal revisions
-
VK_EXT_sample_locations
- Name String
-
VK_EXT_sample_locations - Extension Type
-
Device extension
- Registered Extension Number
-
144
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Daniel Rakos @drakos-amd
-
- Last Modified Date
-
2017-08-02
- Contributors
-
-
Mais Alnasser, AMD
-
Matthaeus G. Chajdas, AMD
-
Maciej Jesionowski, AMD
-
Daniel Rakos, AMD
-
Slawomir Grajewski, Intel
-
Jeff Bolz, NVIDIA
-
Bill Licea-Kane, Qualcomm
-
This extension allows an application to modify the locations of samples within a pixel used in rasterization. Additionally, it allows applications to specify different sample locations for each pixel in a group of adjacent pixels, which can increase antialiasing quality (particularly if a custom resolve shader is used that takes advantage of these different locations).
It is common for implementations to optimize the storage of depth values by storing values that can be used to reconstruct depth at each sample location, rather than storing separate depth values for each sample. For example, the depth values from a single triangle may be represented using plane equations. When the depth value for a sample is needed, it is automatically evaluated at the sample location. Modifying the sample locations causes the reconstruction to no longer evaluate the same depth values as when the samples were originally generated, thus the depth aspect of a depth/stencil attachment must be cleared before rendering to it using different sample locations.
Some implementations may need to evaluate depth image values while performing image layout transitions. To accommodate this, instances of the VkSampleLocationsInfoEXT structure can be specified for each situation where an explicit or automatic layout transition has to take place. VkSampleLocationsInfoEXT can be chained from VkImageMemoryBarrier structures to provide sample locations for layout transitions performed by vkCmdWaitEvents and vkCmdPipelineBarrier calls, and VkRenderPassSampleLocationsBeginInfoEXT can be chained from VkRenderPassBeginInfo to provide sample locations for layout transitions performed implicitly by a render pass instance.
New Object Types
None.
New Enum Constants
-
Extending VkImageCreateFlagBits:
-
VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT
-
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_SAMPLE_LOCATIONS_INFO_EXT -
VK_STRUCTURE_TYPE_RENDER_PASS_SAMPLE_LOCATIONS_BEGIN_INFO_EXT -
VK_STRUCTURE_TYPE_PIPELINE_SAMPLE_LOCATIONS_STATE_CREATE_INFO_EXT -
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLE_LOCATIONS_PROPERTIES_EXT -
VK_STRUCTURE_TYPE_MULTISAMPLE_PROPERTIES_EXT
-
-
Extending VkDynamicState:
-
VK_DYNAMIC_STATE_SAMPLE_LOCATIONS_EXT
-
New Enums
None.
New Structures
Issues
None.
Version History
-
Revision 1, 2017-08-02 (Daniel Rakos)
-
Internal revisions
-
VK_EXT_sampler_filter_minmax
- Name String
-
VK_EXT_sampler_filter_minmax - Extension Type
-
Device extension
- Registered Extension Number
-
131
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Jeff Bolz @jeffbolznv
-
- Last Modified Date
-
2017-05-19
- IP Status
-
No known IP claims.
- Contributors
-
-
Jeff Bolz, NVIDIA
-
Piers Daniell, NVIDIA
-
In unextended Vulkan, minification and magnification filters such as LINEAR allow sampled image lookups to return a filtered texel value produced by computing a weighted average of a collection of texels in the neighborhood of the texture coordinate provided.
This extension provides a new sampler parameter which allows applications to produce a filtered texel value by computing a component-wise minimum (MIN) or maximum (MAX) of the texels that would normally be averaged. The reduction mode is orthogonal to the minification and magnification filter parameters. The filter parameters are used to identify the set of texels used to produce a final filtered value; the reduction mode identifies how these texels are combined.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLER_FILTER_MINMAX_PROPERTIES_EXT -
VK_STRUCTURE_TYPE_SAMPLER_REDUCTION_MODE_CREATE_INFO_EXT
-
-
Extending VkFormatFeatureFlagBits
-
VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_MINMAX_BIT_EXT
-
New Enums
New Functions
None.
New Built-In Variables
None.
New SPIR-V Capabilities
None.
Issues
None.
Examples
None.
Version History
-
Revision 2, 2017-05-19 (Piers Daniell)
-
Renamed to EXT
-
-
Revision 1, 2017-03-25 (Jeff Bolz)
-
Internal revisions
-
VK_EXT_shader_stencil_export
- Name String
-
VK_EXT_shader_stencil_export - Extension Type
-
Device extension
- Registered Extension Number
-
141
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Dominik Witczak @dominikwitczakamd
-
- Last Modified Date
-
2017-07-19
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Requires the SPV_EXT_shader_stencil_export SPIR-V extension.
-
- Contributors
-
-
Dominik Witczak, AMD
-
Daniel Rakos, AMD
-
Rex Xu, AMD
-
This extension adds support for the SPIR-V extension SPV_EXT_shader_stencil_export, providing a mechanism whereby a shader may generate the stencil reference value per invocation. When stencil testing is enabled, this allows the test to be performed against the value generated in the shader.
Version History
-
Revision 1, 2017-07-19 (Dominik Witczak)
-
Initial draft
-
VK_EXT_shader_subgroup_ballot
- Name String
-
VK_EXT_shader_subgroup_ballot - Extension Type
-
Device extension
- Registered Extension Number
-
65
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Daniel Koch @dgkoch
-
- Last Modified Date
-
2016-11-28
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
This extension requires the SPV_KHR_shader_ballot SPIR-V extension.
-
This extension requires the GL_ARB_shader_ballot extension for GLSL source languages.
-
- Contributors
-
-
Jeff Bolz, NVIDIA
-
Neil Henning, Codeplay
-
Daniel Koch, NVIDIA Corporation
-
This extension adds support for the following SPIR-V extension in Vulkan:
-
SPV_KHR_shader_ballot
This extension provides the ability for a group of invocations, which execute in parallel, to do limited forms of cross-invocation communication via a group broadcast of a invocation value, or broadcast of a bitarray representing a predicate value from each invocation in the group.
This extension provides access to a number of additional built-in shader variables in Vulkan:
-
SubgroupEqMaskKHR, which contains the subgroup mask of the current subgroup invocation, -
SubgroupGeMaskKHR, which contains the subgroup mask of the invocations greater than or equal to the current invocation, -
SubgroupGtMaskKHR, which contains the subgroup mask of the invocations greater than the current invocation, -
SubgroupLeMaskKHR, which contains the subgroup mask of the invocations less than or equal to the current invocation, -
SubgroupLtMaskKHR, which contains the subgroup mask of the invocations less than the current invocation, -
SubgroupLocalInvocationId, which contains the index of an invocation within a subgroup, and -
SubgroupSize, which contains the maximum number of invocations in a subgroup.
Additionally, this extension provides access to the new SPIR-V instructions:
-
OpSubgroupBallotKHR, -
OpSubgroupFirstInvocationKHR, and -
OpSubgroupReadInvocationKHR,
When using GLSL source-based shader languages, the following variables and shader functions from GL_ARB_shader_ballot can map to these SPIR-V built-in decorations and instructions:
-
in uint64_t gl_SubGroupEqMaskARB;→SubgroupEqMaskKHR, -
in uint64_t gl_SubGroupGeMaskARB;→SubgroupGeMaskKHR, -
in uint64_t gl_SubGroupGtMaskARB;→SubgroupGtMaskKHR, -
in uint64_t gl_SubGroupLeMaskARB;→SubgroupLeMaskKHR, -
in uint64_t gl_SubGroupLtMaskARB;→SubgroupLtMaskKHR, -
in uint gl_SubGroupInvocationARB;→SubgroupLocalInvocationId, -
uniform uint gl_SubGroupSizeARB;→SubgroupSize, -
ballotARB() →OpSubgroupBallotKHR, -
readFirstInvocationARB() →OpSubgroupFirstInvocationKHR, and -
readInvocationARB() →OpSubgroupReadInvocationKHR.
New Object Types
None.
New Enum Constants
None.
New Enums
None.
New Structures
None.
New Functions
None.
New Built-In Variables
New SPIR-V Capabilities
Issues
None.
Version History
-
Revision 1, 2016-11-28 (Daniel Koch)
-
Initial draft
-
VK_EXT_shader_subgroup_vote
- Name String
-
VK_EXT_shader_subgroup_vote - Extension Type
-
Device extension
- Registered Extension Number
-
66
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Daniel Koch @dgkoch
-
- Last Modified Date
-
2016-11-28
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
This extension requires the SPV_KHR_subgroup_vote SPIR-V extension.
-
This extension requires the GL_ARB_shader_group_vote extension for GLSL source languages.
-
- Contributors
-
-
Neil Henning, Codeplay
-
Daniel Koch, NVIDIA Corporation
-
This extension adds support for the following SPIR-V extension in Vulkan:
-
SPV_KHR_subgroup_vote
This extension provides new SPIR-V instructions:
-
OpSubgroupAllKHR, -
OpSubgroupAnyKHR, and -
OpSubgroupAllEqualKHR.
to compute the composite of a set of boolean conditions across a group of shader invocations that are running concurrently (a subgroup). These composite results may be used to execute shaders more efficiently on a VkPhysicalDevice.
When using GLSL source-based shader languages, the following shader functions from GL_ARB_shader_group_vote can map to these SPIR-V instructions:
-
anyInvocationARB() →OpSubgroupAnyKHR, -
allInvocationsARB() →OpSubgroupAllKHR, and -
allInvocationsEqualARB() →OpSubgroupAllEqualKHR.
The subgroup across which the boolean conditions are evaluated is implementation-dependent, and this extension provides no guarantee over how individual shader invocations are assigned to subgroups. In particular, a subgroup has no necessary relationship with the compute shader local workgroup — any pair of shader invocations in a compute local workgroup may execute in different subgroups as used by these instructions.
Compute shaders operate on an explicitly specified group of threads (a local workgroup), but many implementations will also group non-compute shader invocations and execute them concurrently. When executing code like
if (condition) {
result = do_fast_path();
} else {
result = do_general_path();
}
where condition diverges between invocations, an implementation might
first execute do_fast_path() for the invocations where condition
is true and leave the other invocations dormant.
Once do_fast_path() returns, it might call do_general_path() for
invocations where condition is false and leave the other
invocations dormant.
In this case, the shader executes both the fast and the general path and
might be better off just using the general path for all invocations.
This extension provides the ability to avoid divergent execution by evaluating a condition across an entire subgroup using code like:
if (allInvocationsARB(condition)) {
result = do_fast_path();
} else {
result = do_general_path();
}
The built-in function allInvocationsARB() will return the same value
for all invocations in the group, so the group will either execute
do_fast_path() or do_general_path(), but never both.
For example, shader code might want to evaluate a complex function
iteratively by starting with an approximation of the result and then
refining the approximation.
Some input values may require a small number of iterations to generate an
accurate result (do_fast_path) while others require a larger number
(do_general_path).
In another example, shader code might want to evaluate a complex function
(do_general_path) that can be greatly simplified when assuming a
specific value for one of its inputs (do_fast_path).
New Object Types
None.
New Enum Constants
None.
New Enums
None.
New Structures
None.
New Functions
None.
New Built-In Variables
None.
New SPIR-V Capabilities
Issues
None.
Version History
-
Revision 1, 2016-11-28 (Daniel Koch)
-
Initial draft
-
VK_EXT_shader_viewport_index_layer
- Name String
-
VK_EXT_shader_viewport_index_layer - Extension Type
-
Device extension
- Registered Extension Number
-
163
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Daniel Koch @dgkoch
-
- Last Modified Date
-
2017-08-08
- Interactions and External Dependencies
-
-
This extension requires the SPV_EXT_shader_viewport_index_layer SPIR-V extension.
-
This extension requires the GL_ARB_shader_viewport_layer_array, GL_AMD_vertex_shader_layer, GL_AMD_vertex_shader_viewport_index, or GL_NV_viewport_array2 extensions for GLSL source languages.
-
This extension requires the
multiViewportfeature. -
This extension interacts with the
tessellationShaderfeature.
-
- Contributors
-
-
Piers Daniell, NVIDIA
-
Jeff Bolz, NVIDIA
-
Jan-Harald Fredriksen, ARM
-
Daniel Rakos, AMD
-
Slawomir Grajeswki, Intel
-
This extension adds support for the ShaderViewportIndexLayerEXT
capability from the SPV_EXT_shader_viewport_index_layer extension in
Vulkan.
This extension allows variables decorated with the Layer and
ViewportIndex built-ins to be exported from vertex or tessellation
shaders, using the ShaderViewportIndexLayerEXT capability.
When using GLSL source-based shading languages, the gl_ViewportIndex
and gl_Layer built-in variables map to the SPIR-V ViewportIndex
and Layer built-in decorations, respectively.
Behaviour of these variables is extended as described in the
GL_ARB_shader_viewport_layer_array (or the precursor
GL_AMD_vertex_shader_layer, GL_AMD_vertex_shader_viewport_index, and
GL_NV_viewport_array2 extensions).
|
Note
The |
New Object Types
None.
New Enum Constants
None.
New Enums
None.
New Structures
None.
New Functions
None.
New or Modified Built-In Variables
-
(modified)
Layer -
(modified)
ViewportIndex
New Variable Decoration
None.
New SPIR-V Capabilities
Issues
None yet!
Version History
-
Revision 1, 2017-08-08 (Daniel Koch)
-
Internal drafts
-
VK_EXT_swapchain_colorspace
- Name String
-
VK_EXT_swapchain_colorspace - Extension Type
-
Instance extension
- Registered Extension Number
-
105
- Revision
-
3
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_surface
-
- Contact
-
-
Courtney Goeltzenleuchter @courtney-g
-
- Last Modified Date
-
2017-03-15
- IP Status
-
No known IP claims.
- Contributors
-
-
Courtney Goeltzenleuchter, Google
-
New Enum Constants
-
Extending VkColorSpaceKHR:
-
VK_COLOR_SPACE_DISPLAY_P3_NONLINEAR_EXT- supports the Display-P3 color space and applies an sRGB-like transfer function. -
VK_COLOR_SPACE_EXTENDED_SRGB_LINEAR_EXT- supports the extended sRGB color space and applies a linear transfer function. -
VK_COLOR_SPACE_EXTENDED_SRGB_NONLINEAR_EXT- supports the extended sRGB color space with an sRGB nonlinear transfer function. -
VK_COLOR_SPACE_DCI_P3_LINEAR_EXT- supports the DCI-P3 color space and applies a linear OETF. -
VK_COLOR_SPACE_DCI_P3_NONLINEAR_EXT- supports the DCI-P3 color space and applies the Gamma 2.6 OETF. -
VK_COLOR_SPACE_BT709_LINEAR_EXT- supports the BT709 color space and applies a linear transfer function. -
VK_COLOR_SPACE_BT709_NONLINEAR_EXT- supports the BT709 color space and applies the SMPTE 170M OETF. -
VK_COLOR_SPACE_BT2020_LINEAR_EXT- supports the BT2020 color space and applies a linear OETF. -
VK_COLOR_SPACE_HDR10_ST2084_EXT- supports HDR10 (BT2020 color space and applies the SMPTE ST2084 Perceptual Quantizer (PQ) OETF). -
VK_COLOR_SPACE_DOLBYVISION_EXT- supports Dolby Vision (BT2020 color space, proprietary encoding, and applies the SMPTE ST2084 OETF). -
VK_COLOR_SPACE_HDR10_HLG_EXT- supports HDR10 (BT2020 color space and applies the Hybrid Log Gamma (HLG) OETF). -
VK_COLOR_SPACE_ADOBERGB_LINEAR_EXT- supports the AdobeRGB color space and applies a linear OETF. -
VK_COLOR_SPACE_ADOBERGB_NONLINEAR_EXT- supports the AdobeRGB color space and applies the Gamma 2.2 OETF. -
VK_COLOR_SPACE_PASS_THROUGH_EXT- color components used “as is”. Intended to allow application to supply data for color spaces not described here.
-
Issues
1) Does the spec need to specify which kinds of image formats support the color spaces?
RESOLVED: Pixel format is independent of color space (though some color spaces really want / need floating point color components to be useful). Therefore, do not plan on documenting what formats support which colorspaces. An application can call vkGetPhysicalDeviceSurfaceFormatsKHR to query what a particular implementation supports.
2) How does application determine if HW supports appropriate transfer function for a colorspace?
RESOLVED: Extension indicates that implementation must not do the OETF encoding if it is not sRGB. That responsibility falls to the application shaders. Any other native OETF / EOTF functions supported by an implementation can be described by separate extension.
Version History
-
Revision 1, 2016-12-27 (Courtney Goeltzenleuchter)
-
Initial version
-
-
Revision 2, 2017-01-19 (Courtney Goeltzenleuchter)
-
Add pass through and multiple options for BT2020.
-
Clean up some issues with equations not displaying properly.
-
-
Revision 3, 2017-06-23 (Courtney Goeltzenleuchter)
-
Add extended sRGB non-linear enum.
-
VK_EXT_validation_flags
- Name String
-
VK_EXT_validation_flags - Extension Type
-
Instance extension
- Registered Extension Number
-
62
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Tobin Ehlis @tobine
-
- Last Modified Date
-
2016-09-06
- IP Status
-
No known IP claims.
- Contributors
-
-
Tobin Ehlis, Google
-
Courtney Goeltzenleuchter, Google
-
This extension provides the VkValidationFlagsEXT struct that can be
included in the pNext chain of the VkInstanceCreateInfo
structure passed as the pCreateInfo parameter of
vkCreateInstance.
The new struct contains an array of VkValidationCheckEXT values that
will be disabled by the validation layers.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_VALIDATION_FLAGS_EXT
-
New Enums
New Structures
New Functions
None.
Issues
None.
Version History
-
Revision 1, 2016-08-26 (Courtney Goeltzenleuchter)
-
Initial draft
-
VK_EXT_validation_cache
- Name String
-
VK_EXT_validation_cache - Extension Type
-
Device extension
- Registered Extension Number
-
161
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Cort Stratton @cdwfs
-
- Last Modified Date
-
2017-08-29
- IP Status
-
No known IP claims.
- Contributors
-
-
Cort Stratton, Google
-
Chris Forbes, Google
-
This extension provides a mechanism for caching the results of potentially expensive internal validation operations across multiple runs of a Vulkan application. At the core is the VkValidationCacheEXT object type, which is managed similarly to the existing VkPipelineCache.
The new struct VkShaderModuleValidationCacheCreateInfoEXT can be
included in the pNext chain at vkCreateShaderModule time.
It contains a VkValidationCacheEXT to use when validating the
VkShaderModule.
New Object Types
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_VALIDATION_CACHE_CREATE_INFO_EXT -
VK_STRUCTURE_TYPE_SHADER_MODULE_VALIDATION_CACHE_CREATE_INFO_EXT
-
New Functions
Issues
None.
Version History
-
Revision 1, 2017-08-29 (Cort Stratton)
-
Initial draft
-
VK_EXT_vertex_attribute_divisor
- Name String
-
VK_EXT_vertex_attribute_divisor - Extension Type
-
Device extension
- Registered Extension Number
-
191
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Vikram Kushwaha @vkushwaha
-
- Last Modified Date
-
2018-02-08
- IP Status
-
No known IP claims.
- Contributors
-
-
Vikram Kushwaha, NVIDIA
-
This extension allows instance-rate vertex attributes to be repeated for certain number of instances instead of advancing for every instance when instanced rendering is enabled.
New Object Types
None.
New Enum Constants
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VERTEX_ATTRIBUTE_DIVISOR_PROPERTIES_EXT -
VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_DIVISOR_STATE_CREATE_INFO_EXT
New Enums
None.
New Structures
New Functions
None.
Issues
None.
Examples
To create a vertex binding such that the first binding uses instanced rendering and the same attribute is used for every 4 draw instances, an application could use the following set of structures:
const VkVertexInputBindingDivisorDescriptionEXT divisorDesc =
{
0,
4
};
const VkPipelineVertexInputDivisorStateCreateInfoEXT divisorInfo =
{
VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_DIVISOR_STATE_CREATE_INFO_EXT, // sType
NULL, // pNext
1, // vertexBindingDivisorCount
&divisorDesc // pVertexBindingDivisors
}
const VkVertexInputBindingDescription binding =
{
0, // binding
sizeof(Vertex), // stride
VK_VERTEX_INPUT_RATE_INSTANCE // inputRate
};
const VkPipelineVertexInputStateCreateInfo viInfo =
{
VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_CREATE_INFO, // sType
&divisorInfo, // pNext
...
};
//...
Version History
-
Revision 1, 2017-12-04 (Vikram Kushwaha)
-
First Version
-
VK_AMD_buffer_marker
- Name String
-
VK_AMD_buffer_marker - Extension Type
-
Device extension
- Registered Extension Number
-
180
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Daniel Rakos @drakos-amd
-
- Last Modified Date
-
2018-01-26
- IP Status
-
No known IP claims.
- Contributors
-
-
Matthaeus G. Chajdas, AMD
-
Jaakko Konttinen, AMD
-
Daniel Rakos, AMD
-
This extension adds a new operation to execute pipelined writes of small
marker values into a VkBuffer object.
The primary purpose of these markers is to facilitate the development of debugging tools for tracking which pipelined command contributed to device loss.
New Object Types
None.
New Enum Constants
None.
New Enums
None.
New Structures
None.
New Functions
Examples
None.
Version History
-
Revision 1, 2018-01-26 (Jaakko Konttinen)
-
Initial revision
-
VK_AMD_draw_indirect_count
- Name String
-
VK_AMD_draw_indirect_count - Extension Type
-
Device extension
- Registered Extension Number
-
34
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Daniel Rakos @drakos-amd
-
- Last Modified Date
-
2016-08-23
- IP Status
-
No known IP claims.
- Contributors
-
-
Matthaeus G. Chajdas, AMD
-
Derrick Owens, AMD
-
Graham Sellers, AMD
-
Daniel Rakos, AMD
-
Dominik Witczak, AMD
-
This extension allows an application to source the number of draw calls for indirect draw calls from a buffer. This enables applications to generate arbitrary amounts of draw commands and execute them without host intervention.
New Functions
Version History
-
Revision 2, 2016-08-23 (Dominik Witczak)
-
Minor fixes
-
-
Revision 1, 2016-07-21 (Matthaeus Chajdas)
-
Initial draft
-
VK_AMD_gcn_shader
- Name String
-
VK_AMD_gcn_shader - Extension Type
-
Device extension
- Registered Extension Number
-
26
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Dominik Witczak @dominikwitczakamd
-
- Last Modified Date
-
2016-05-30
- IP Status
-
No known IP claims.
- Contributors
-
-
Dominik Witczak, AMD
-
Daniel Rakos, AMD
-
Rex Xu, AMD
-
Graham Sellers, AMD
-
This extension adds support for the following SPIR-V extension in Vulkan:
|
editing-note
Shouldn’t the SPV extension be in the Interactions and External Dependencies block? |
Version History
-
Revision 1, 2016-05-30 (Dominik Witczak)
-
Initial draft
-
VK_AMD_gpu_shader_half_float
- Name String
-
VK_AMD_gpu_shader_half_float - Extension Type
-
Device extension
- Registered Extension Number
-
37
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Dominik Witczak @dominikwitczakamd
-
- Last Modified Date
-
2016-09-21
- IP Status
-
No known IP claims.
- Contributors
-
-
Daniel Rakos, AMD
-
Dominik Witczak, AMD
-
Donglin Wei, AMD
-
Graham Sellers, AMD
-
Qun Lin, AMD
-
Rex Xu, AMD
-
This extension adds support for the following SPIR-V extension in Vulkan:
|
editing-note
Shouldn’t the SPV extension be in the Interactions and External Dependencies block? |
Version History
-
Revision 1, 2019-09-21 (Dominik Witczak)
-
Initial draft
-
VK_AMD_gpu_shader_int16
- Name String
-
VK_AMD_gpu_shader_int16 - Extension Type
-
Device extension
- Registered Extension Number
-
133
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Qun Lin, AMD @linqun
-
- Last Modified Date
-
2017-06-08
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Requires the SPV_AMD_gpu_shader_int16 SPIR-V extension.
-
- Contributors
-
-
Daniel Rakos, AMD
-
Dominik Witczak, AMD
-
Matthaeus G. Chajdas, AMD
-
Rex Xu, AMD
-
Timothy Lottes, AMD
-
Zhi Cai, AMD
-
This extension adds support for the following SPIR-V extension in Vulkan:
-
SPV_AMD_gpu_shader_int16
Version History
-
Revision 1, 2017-06-18 (Dominik Witczak)
-
First version.
-
VK_AMD_mixed_attachment_samples
- Name String
-
VK_AMD_mixed_attachment_samples - Extension Type
-
Device extension
- Registered Extension Number
-
137
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Matthaeus G. Chajdas @anteru
-
- Last Modified Date
-
2017-07-24
- Contributors
-
-
Mais Alnasser, AMD
-
Matthaeus G. Chajdas, AMD
-
Maciej Jesionowski, AMD
-
Daniel Rakos, AMD
-
This extension enables applications to use multisampled rendering with a depth/stencil sample count that is larger than the color sample count. Having a depth/stencil sample count larger than the color sample count allows maintaining geometry and coverage information at a higher sample rate than color information. All samples are depth/stencil tested, but only the first color sample count number of samples get a corresponding color output.
New Object Types
None.
New Enum Constants
None.
New Enums
None.
New Structures
None.
New Functions
None.
Issues
None.
Version History
-
Revision 1, 2017-07-24 (Daniel Rakos)
-
Internal revisions
-
VK_AMD_negative_viewport_height
- Name String
-
VK_AMD_negative_viewport_height - Extension Type
-
Device extension
- Registered Extension Number
-
36
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Matthaeus G. Chajdas @anteru
-
- Last Modified Date
-
2016-09-02
- IP Status
-
No known IP claims.
- Contributors
-
-
Matthaeus G. Chajdas, AMD
-
Graham Sellers, AMD
-
Baldur Karlsson
-
- Interactions and External Dependencies
-
-
Deprecated by VK_KHR_maintenance1
-
Deprecated by Vulkan 1.1
-
This extension allows an application to specify a negative viewport height. The result is that the viewport transformation will flip along the y-axis.
-
Allow negative height to be specified in the slink::VkViewport::
heightfield to perform y-inversion of the clip-space to framebuffer-space transform. This allows apps to avoid having to use gl_Position.y = -gl_Position.y in shaders also targeting other APIs.
Deprecation by VK_KHR_maintenance1 and Vulkan 1.1
Functionality in this extension is included in VK_KHR_maintenance1 and
Vulkan 1.1.
Due to some slight behavioral differences, this extension must not be
enabled alongside VK_KHR_maintenance1, or in an instance created with
version 1.1 or later requested in VkApplicationInfo::apiVersion.
Version History
-
Revision 1, 2016-09-02 (Matthaeus Chajdas)
-
Initial draft
-
VK_AMD_rasterization_order
- Name String
-
VK_AMD_rasterization_order - Extension Type
-
Device extension
- Registered Extension Number
-
19
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Daniel Rakos @drakos-amd
-
- Last Modified Date
-
2016-04-25
- IP Status
-
No known IP claims.
- Contributors
-
-
Matthaeus G. Chajdas, AMD
-
Jaakko Konttinen, AMD
-
Daniel Rakos, AMD
-
Graham Sellers, AMD
-
Dominik Witczak, AMD
-
This extension introduces the possibility for the application to control the order of primitive rasterization. In unextended Vulkan, the following stages are guaranteed to execute in API order:
-
depth bounds test
-
stencil test, stencil op, and stencil write
-
depth test and depth write
-
occlusion queries
-
blending, logic op, and color write
This extension enables applications to opt into a relaxed, implementation defined primitive rasterization order that may allow better parallel processing of primitives and thus enabling higher primitive throughput. It is applicable in cases where the primitive rasterization order is known to not affect the output of the rendering or any differences caused by a different rasterization order are not a concern from the point of view of the application’s purpose.
A few examples of cases when using the relaxed primitive rasterization order would not have an effect on the final rendering:
-
If the primitives rendered are known to not overlap in framebuffer space.
-
If depth testing is used with a comparison operator of
VK_COMPARE_OP_LESS,VK_COMPARE_OP_LESS_OR_EQUAL,VK_COMPARE_OP_GREATER, orVK_COMPARE_OP_GREATER_OR_EQUAL, and the primitives rendered are known to not overlap in clip space. -
If depth testing is not used and blending is enabled for all attachments with a commutative blend operator.
New Object Types
None
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_RASTERIZATION_ORDER_AMD
-
New Enums
New Structures
New Functions
None
Issues
1) How is this extension useful to application developers?
RESOLVED: Allows them to increase primitive throughput for cases when strict API order rasterization is not important due to the nature of the content, the configuration used, or the requirements towards the output of the rendering.
2) How does this extension interact with content optimizations aiming to reduce overdraw by appropriately ordering the input primitives?
RESOLVED: While the relaxed rasterization order might somewhat limit the effectiveness of such content optimizations, most of the benefits of it are expected to be retained even when the relaxed rasterization order is used, so applications should still apply these optimizations even if they intend to use the extension.
3) Are there any guarantees about the primitive rasterization order when using the new relaxed mode?
RESOLVED: No. In this case the rasterization order is completely implementation dependent, but in practice it is expected to partially still follow the order of incoming primitives.
4) Does the new relaxed rasterization order have any adverse effect on repeatability and other invariance rules of the API?
RESOLVED: Yes, in the sense that it extends the list of exceptions when the repeatability requirement does not apply.
Examples
None
Issues
None
Version History
-
Revision 1, 2016-04-25 (Daniel Rakos)
-
Initial draft.
-
VK_AMD_shader_ballot
- Name String
-
VK_AMD_shader_ballot - Extension Type
-
Device extension
- Registered Extension Number
-
38
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Dominik Witczak @dominikwitczakamd
-
- Last Modified Date
-
2016-09-19
- IP Status
-
No known IP claims.
- Contributors
-
-
Qun Lin, AMD
-
Graham Sellers, AMD
-
Daniel Rakos, AMD
-
Rex Xu, AMD
-
Dominik Witczak, AMD
-
Matthäus G. Chajdas, AMD
-
This extension adds support for the following SPIR-V extension in Vulkan:
|
editing-note
Shouldn’t the SPV extension be in the Interactions and External Dependencies block? |
Version History
-
Revision 1, 2016-09-19 (Dominik Witczak)
-
Initial draft
-
VK_AMD_shader_core_properties
- Name String
-
VK_AMD_shader_core_properties - Extension Type
-
Device extension
- Registered Extension Number
-
186
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Martin Dinkov @mdinkov
-
- Last Modified Date
-
2018-02-15
- IP Status
-
No known IP claims.
- Contributors
-
-
Martin Dinkov, AMD
-
Matthaeus Chajdas, AMD
-
This extension exposes shader core properties for a target physical device through the VK_KHR_get_physical_device_properties2 extension. Please refer to the example below for proper usage.
New Object Types
None.
New Enum Constants
-
Extending
VkStructureType:-
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_CORE_PROPERTIES_AMD
-
New Enums
None.
New Structures
New Functions
None.
Examples
This example retrieves the shader core properties for a physical device.
extern VkInstance instance;
PFN_vkGetPhysicalDeviceProperties2 pfnVkGetPhysicalDeviceProperties2 =
reinterpret_cast<PFN_vkGetPhysicalDeviceProperties2>
(vkGetInstanceProcAddr(instance, "vkGetPhysicalDeviceProperties2") );
VkPhysicalDeviceProperties2 general_props;
VkPhysicalDeviceShaderCorePropertiesAMD shader_core_properties;
shader_core_properties.pNext = nullptr;
shader_core_properties.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_CORE_PROPERTIES_AMD;
general_props.pNext = &shader_core_properties;
general_props.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2;
// After this call, shader_core_properties has been populated
pfnVkGetPhysicalDeviceProperties2(device, &general_props);
printf("Number of shader engines: %d\n",
m_shader_core_properties.shader_engine_count =
shader_core_properties.shaderEngineCount;
printf("Number of shader arrays: %d\n",
m_shader_core_properties.shader_arrays_per_engine_count =
shader_core_properties.shaderArraysPerEngineCount;
printf("Number of CUs per shader array: %d\n",
m_shader_core_properties.compute_units_per_shader_array =
shader_core_properties.computeUnitsPerShaderArray;
printf("Number of SIMDs per compute unit: %d\n",
m_shader_core_properties.simd_per_compute_unit =
shader_core_properties.simdPerComputeUnit;
printf("Number of wavefront slots in each SIMD: %d\n",
m_shader_core_properties.wavefronts_per_simd =
shader_core_properties.wavefrontsPerSimd;
printf("Number of threads per wavefront: %d\n",
m_shader_core_properties.wavefront_size =
shader_core_properties.wavefrontSize;
printf("Number of physical SGPRs per SIMD: %d\n",
m_shader_core_properties.sgprs_per_simd =
shader_core_properties.sgprsPerSimd;
printf("Minimum number of SGPRs that can be allocated by a wave: %d\n",
m_shader_core_properties.min_sgpr_allocation =
shader_core_properties.minSgprAllocation;
printf("Number of available SGPRs: %d\n",
m_shader_core_properties.max_sgpr_allocation =
shader_core_properties.maxSgprAllocation;
printf("SGPRs are allocated in groups of this size: %d\n",
m_shader_core_properties.sgpr_allocation_granularity =
shader_core_properties.sgprAllocationGranularity;
printf("Number of physical VGPRs per SIMD: %d\n",
m_shader_core_properties.vgprs_per_simd =
shader_core_properties.vgprsPerSimd;
printf("Minimum number of VGPRs that can be allocated by a wave: %d\n",
m_shader_core_properties.min_vgpr_allocation =
shader_core_properties.minVgprAllocation;
printf("Number of available VGPRs: %d\n",
m_shader_core_properties.max_vgpr_allocation =
shader_core_properties.maxVgprAllocation;
printf("VGPRs are allocated in groups of this size: %d\n",
m_shader_core_properties.vgpr_allocation_granularity =
shader_core_properties.vgprAllocationGranularity;
Version History
-
Revision 1, 2018-02-15 (Martin Dinkov)
-
Initial draft.
-
VK_AMD_shader_explicit_vertex_parameter
- Name String
-
VK_AMD_shader_explicit_vertex_parameter - Extension Type
-
Device extension
- Registered Extension Number
-
22
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Qun Lin, AMD @linqun
-
- Last Modified Date
-
2016-05-10
- IP Status
-
No known IP claims.
- Contributors
-
-
Matthaeus G. Chajdas, AMD
-
Qun Lin, AMD
-
Daniel Rakos, AMD
-
Graham Sellers, AMD
-
Rex Xu, AMD
-
This extension adds support for the following SPIR-V extension in Vulkan:
|
editing-note
Shouldn’t the SPV extension be in the Interactions and External Dependencies block? |
Version History
-
Revision 1, 2016-05-10 (Daniel Rakos)
-
Initial draft
-
VK_AMD_shader_fragment_mask
- Name String
-
VK_AMD_shader_fragment_mask - Extension Type
-
Device extension
- Registered Extension Number
-
138
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Aaron Hagan @AaronHaganAMD
-
- Last Modified Date
-
2017-08-16
- IP Status
-
No known IP claims.
- Dependencies
-
-
Requires the SPV_AMD_shader_fragment_mask SPIR-V extension.
-
- Contributors
-
-
Aaron Hagan, AMD
-
Daniel Rakos, AMD
-
Timothy Lottes, AMD
-
This extension provides efficient read access to the fragment mask in compressed multisampled color surfaces. The fragment mask is a lookup table that associates color samples with color fragment values.
From a shader, the fragment mask can be fetched with a call to
fragmentMaskFetchAMD, which returns a single uint where each
subsequent four bits specify the color fragment index corresponding to the
color sample, starting from the least significant bit.
For example, when eight color samples are used, the color fragment index for
color sample 0 will be in bits 0-3 of the fragment mask, for color sample 7
the index will be in bits 28-31.
The color fragment for a particular color sample may then be fetched with
the corresponding fragment mask value using the fragmentFetchAMD shader
function.
New Object Types
None.
New Enum Constants
None.
New Enums
None.
New SPIR-V Capabilities
New Structures
None.
New Functions
None.
Examples
This example shows a shader that queries the fragment mask from a multisampled compressed surface and uses it to query fragment values.
#version 450 core
#extension GL_AMD_shader_fragment_mask: enable
layout(binding = 0) uniform sampler2DMS s2DMS;
layout(binding = 1) uniform isampler2DMSArray is2DMSArray;
layout(binding = 2, input_attachment_index = 0) uniform usubpassInputMS usubpassMS;
layout(location = 0) out vec4 fragColor;
void main()
{
vec4 fragOne = vec4(0.0);
uint fragMask = fragmentMaskFetchAMD(s2DMS, ivec2(2, 3));
uint fragIndex = (fragMask & 0xF0) >> 4;
fragOne += fragmentFetchAMD(s2DMS, ivec2(2, 3), 1);
fragMask = fragmentMaskFetchAMD(is2DMSArray, ivec3(2, 3, 1));
fragIndex = (fragMask & 0xF0) >> 4;
fragOne += fragmentFetchAMD(is2DMSArray, ivec3(2, 3, 1), fragIndex);
fragMask = fragmentMaskFetchAMD(usubpassMS);
fragIndex = (fragMask & 0xF0) >> 4;
fragOne += fragmentFetchAMD(usubpassMS, fragIndex);
fragColor = fragOne;
}
Version History
-
Revision 1, 2017-08-16 (Aaron Hagan)
-
Initial draft
-
VK_AMD_shader_image_load_store_lod
- Name String
-
VK_AMD_shader_image_load_store_lod - Extension Type
-
Device extension
- Registered Extension Number
-
47
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Dominik Witczak @dominikwitczakamd
-
- Last Modified Date
-
2017-08-21
- Interactions and External Dependencies
-
-
This extension requires the SPV_AMD_shader_image_load_store_lod SPIR-V extension.
-
This extension requires GL_AMD_shader_image_load_store_lod for GLSL-based source languages.
-
- IP Status
-
No known IP claims.
- Contributors
-
-
Dominik Witczak, AMD
-
Qun Lin, AMD
-
Rex Xu, AMD
-
This extension adds support for the following SPIR-V extension in Vulkan:
Version History
-
Revision 1, 2017-08-21 (Dominik Witczak)
-
Initial draft
-
VK_AMD_shader_info
- Name String
-
VK_AMD_shader_info - Extension Type
-
Device extension
- Registered Extension Number
-
43
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Jaakko Konttinen @jaakkoamd
-
- Last Modified Date
-
2017-10-09
- IP Status
-
No known IP claims.
- Contributors
-
-
Jaakko Konttinen, AMD
-
This extension adds a way to query certain information about a compiled shader which is part of a pipeline. This information may include shader disassembly, shader binary and various statistics about a shader’s resource usage.
While this extension provides a mechanism for extracting this information, the details regarding the contents or format of this information are not specified by this extension and may be provided by the vendor externally.
Furthermore, all information types are optionally supported, and users should not assume every implementation supports querying every type of information.
New Object Types
None.
New Enum Constants
None.
New Enums
New Structures
New Functions
Examples
This example extracts the register usage of a fragment shader within a particular graphics pipeline:
extern VkDevice device;
extern VkPipeline gfxPipeline;
PFN_vkGetShaderInfoAMD pfnGetShaderInfoAMD = (PFN_vkGetShaderInfoAMD)vkGetDeviceProcAddr(
device, "vkGetShaderInfoAMD");
VkShaderStatisticsInfoAMD statistics = {};
size_t dataSize = sizeof(statistics);
if (pfnGetShaderInfoAMD(device,
gfxPipeline,
VK_SHADER_STAGE_FRAGMENT_BIT,
VK_SHADER_INFO_TYPE_STATISTICS_AMD,
&dataSize,
&statistics) == VK_SUCCESS)
{
printf("VGPR usage: %d\n", statistics.resourceUsage.numUsedVgprs);
printf("SGPR usage: %d\n", statistics.resourceUsage.numUsedSgprs);
}
The following example continues the previous example by subsequently attempting to query and print shader disassembly about the fragment shader:
// Query disassembly size (if available)
if (pfnGetShaderInfoAMD(device,
gfxPipeline,
VK_SHADER_STAGE_FRAGMENT_BIT,
VK_SHADER_INFO_TYPE_DISASSEMBLY_AMD,
&dataSize,
nullptr) == VK_SUCCESS)
{
printf("Fragment shader disassembly:\n");
void* disassembly = malloc(dataSize);
// Query disassembly and print
if (pfnGetShaderInfoAMD(device,
gfxPipeline,
VK_SHADER_STAGE_FRAGMENT_BIT,
VK_SHADER_INFO_TYPE_DISASSEMBLY_AMD,
&dataSize,
disassembly) == VK_SUCCESS)
{
printf((char*)disassembly);
}
free(disassembly);
}
Version History
-
Revision 1, 2017-10-09 (Jaakko Konttinen)
-
Initial revision
-
VK_AMD_shader_trinary_minmax
- Name String
-
VK_AMD_shader_trinary_minmax - Extension Type
-
Device extension
- Registered Extension Number
-
21
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Qun Lin, AMD @linqun
-
- Last Modified Date
-
2016-05-10
- IP Status
-
No known IP claims.
- Contributors
-
-
Matthaeus G. Chajdas, AMD
-
Qun Lin, AMD
-
Daniel Rakos, AMD
-
Graham Sellers, AMD
-
Rex Xu, AMD
-
This extension adds support for the following SPIR-V extension in Vulkan:
|
editing-note
Shouldn’t the SPV extension be in the Interactions and External Dependencies block? |
Version History
-
Revision 1, 2016-05-10 (Daniel Rakos)
-
Initial draft
-
VK_AMD_texture_gather_bias_lod
- Name String
-
VK_AMD_texture_gather_bias_lod - Extension Type
-
Device extension
- Registered Extension Number
-
42
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Rex Xu @amdrexu
-
- Last Modified Date
-
2017-03-21
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Requires the SPV_AMD_texture_gather_bias_lod SPIR-V extension.
-
- Contributors
-
-
Dominik Witczak, AMD
-
Daniel Rakos, AMD
-
Graham Sellers, AMD
-
Matthaeus G. Chajdas, AMD
-
Qun Lin, AMD
-
Rex Xu, AMD
-
Timothy Lottes, AMD
-
This extension adds two related features.
Firstly, support for the following SPIR-V extension in Vulkan is added:
-
SPV_AMD_texture_gather_bias_lod
Secondly, the extension allows the application to query which formats can be used together with the new function prototypes introduced by the SPIR-V extension.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_TEXTURE_LOD_GATHER_FORMAT_PROPERTIES_AMD
-
New Enums
None.
New SPIR-V Capabilities
New Structures
New Functions
None.
Examples
struct VkTextureLODGatherFormatPropertiesAMD
{
VkStructureType sType;
const void* pNext;
VkBool32 supportsTextureGatherLODBiasAMD;
};
// ----------------------------------------------------------------------------------------
// How to detect if an image format can be used with the new function prototypes.
VkPhysicalDeviceImageFormatInfo2 formatInfo;
VkImageFormatProperties2 formatProps;
VkTextureLODGatherFormatPropertiesAMD textureLODGatherSupport;
textureLODGatherSupport.sType = VK_STRUCTURE_TYPE_TEXTURE_LOD_GATHER_FORMAT_PROPERTIES_AMD;
textureLODGatherSupport.pNext = nullptr;
formatInfo.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_FORMAT_INFO_2;
formatInfo.pNext = nullptr;
formatInfo.format = ...;
formatInfo.type = ...;
formatInfo.tiling = ...;
formatInfo.usage = ...;
formatInfo.flags = ...;
formatProps.sType = VK_STRUCTURE_TYPE_IMAGE_FORMAT_PROPERTIES_2;
formatProps.pNext = &textureLODGatherSupport;
vkGetPhysicalDeviceImageFormatProperties2(physical_device, &formatInfo, &formatProps);
if (textureLODGatherSupport.supportsTextureGatherLODBiasAMD == VK_TRUE)
{
// physical device supports SPV_AMD_texture_gather_bias_lod for the specified
// format configuration.
}
else
{
// physical device does not support SPV_AMD_texture_gather_bias_lod for the
// specified format configuration.
}
Version History
-
Revision 1, 2017-03-21 (Dominik Witczak)
-
Initial draft
-
VK_ANDROID_external_memory_android_hardware_buffer
- Name String
-
VK_ANDROID_external_memory_android_hardware_buffer - Extension Type
-
Device extension
- Registered Extension Number
-
130
- Revision
-
3
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_sampler_ycbcr_conversion -
Requires
VK_KHR_external_memory -
Requires
VK_EXT_queue_family_foreign
-
- Contact
-
-
Jesse Hall @critsec
-
- Status
-
Draft
- Last Modified Date
-
2018-03-04
- IP Status
-
No known IP claims.
- Contributors
-
-
Ray Smith, ARM
-
Chad Versace, Google
-
Jesse Hall, Google
-
Tobias Hector, Imagination
-
James Jones, NVIDIA
-
Tony Zlatinski, NVIDIA
-
Matthew Netsch, Qualcomm
-
Andrew Garrard, Samsung
-
This extension enables an application to import Android AHardwareBuffer objects created outside of the Vulkan device into Vulkan memory objects, where they can be bound to images and buffers. It also allows exporting an AHardwareBuffer from a Vulkan memory object for symmetry with other operating systems. But since not all AHardwareBuffer usages and formats have Vulkan equivalents, exporting from Vulkan provides strictly less functionality than creating the AHardwareBuffer externally and importing it.
Some AHardwareBuffer images have implementation-defined external formats that may not correspond to Vulkan formats. Sampler Y’CbCr conversion can be used to sample from these images and convert them to a known colorspace.
New Object Types
None.
New Enum Constants
-
VK_STRUCTURE_TYPE_ANDROID_HARDWARE_BUFFER_USAGE_ANDROID -
VK_STRUCTURE_TYPE_ANDROID_HARDWARE_BUFFER_PROPERTIES_ANDROID -
VK_STRUCTURE_TYPE_ANDROID_HARDWARE_BUFFER_FORMAT_PROPERTIES_ANDROID -
VK_STRUCTURE_TYPE_IMPORT_ANDROID_HARDWARE_BUFFER_INFO_ANDROID -
VK_STRUCTURE_TYPE_MEMORY_GET_ANDROID_HARDWARE_BUFFER_INFO_ANDROID -
VK_STRUCTURE_TYPE_EXTERNAL_FORMAT_ANDROID -
VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID
New Enums
None.
New Structs
Issues
1) Other external memory objects are represented as weakly-typed handles (e.g. Win32 HANDLE or POSIX file descriptor), and require a handle type parameter along with handles. AHardwareBuffer is strongly typed, so naming the handle type is redundant. Does symmetry justify adding handle type parameters/fields anyway?
RESOLVED: No. The handle type is already provided in places that treat external memory objects generically. In the places we would add it, the application code that would have to provide the handle type value is already dealing with AHardwareBuffer-specific commands/structures; the extra symmetry wouldn’t be enough to make that code generic.
2) The internal layout and therefore size of a AHardwareBuffer image may depend on native usage flags that don’t have corresponding Vulkan counterparts. Do we provide this info to vkCreateImage somehow, or allow the allocation size reported by vkGetImageMemoryRequirements to be approximate?
RESOLVED: Allow the allocation size to be unspecified when allocating the memory. It has to work this way for exported image memory anyway, since AHardwareBuffer allocation happens in vkAllocateMemory, and internally is performed by a separate HAL, not the Vulkan implementation itself. There is a similar issue with vkGetImageSubresourceLayout: the layout is determined by the allocator HAL, so it isn’t known until the image is bound to memory.
3) Should the result of sampling an external-format image with the suggested Y’CbCr conversion parameters yield the same results as using a samplerExternalOES in OpenGL ES?
RESOLVED: This would be desirable, so that apps converting from OpenGL ES to Vulkan could get the same output given the same input. But since sampling and conversion from Y’CbCr images is so loosely defined in OpenGL ES, multiple implementations do it in a way that doesn’t conform to Vulkan’s requirements. Modifying the OpenGL ES implementation would be difficult, and would change the output of existing unmodified applications. Changing the output only for applications that are being modified gives developers the chance to notice and mitigate any problems. Implementations are encouraged to minimize differences as much as possible without causing compatibility problems for existing OpenGL ES applications or violating Vulkan requirements.
4) Should AHardwareBuffers with AHARDWAREBUFFER_USAGE_CPU_* usage be mappable in Vulkan? Should it be possible to export AHardwareBuffers with such usage?
RESOLVED: Optional, and mapping in Vulkan is not the same as
AHardwareBuffer_lock.
The semantics of these are different: mapping in memory is persistent, just
gives a raw view of the memory contents, and doesn’t involve ownership.
AHardwareBuffer_lock gives the host exclusive access to the buffer, is
temporary, and allows for reformatting copy-in/copy-out.
Implementations aren’t required to support host-visible memory types for
imported Android hardware buffers or resources backed by them.
If a host-visible memory type is supported and used, the memory can be
mapped in Vulkan, but doing so follows Vulkan semantics: it’s just a raw
view of the data and doesn’t imply ownership (this means implementations
must not internally call AHardwareBuffer_lock to implement
vkMapMemory, or assume the application has done so).
Implementations aren’t required to support linear-tiled images backed by
Android hardware buffers, even if the AHardwareBuffer has CPU usage.
There is no reliable way to allocate memory in Vulkan that can be exported
to a AHardwareBuffer with CPU usage.
5) Android may add new AHardwareBuffer formats and usage flags over time. Can reference to them be added to this extension, or do they need a new extension?
RESOLVED: This extension can document the interaction between the new AHB formats/usages and existing Vulkan features. No new Vulkan features or implementation requirements can be added. The extension version number will be incremented when this additional documentation is added, but the version number doesn’t indicate that an implementaiton supports Vulkan memory or resources that map to the new AHardwareBuffer features: support for that must be queried with vkGetPhysicalDeviceImageFormatProperties2 or is implied by successfully allocating a AHardwareBuffer outside of Vulkan that uses the new feature and has a GPU usage flag.
In essence, these are new features added to a new Android API level, rather than new Vulkan features. The extension will only document how existing Vulkan features map to that new Android feature.
VK_GOOGLE_display_timing
- Name String
-
VK_GOOGLE_display_timing - Extension Type
-
Device extension
- Registered Extension Number
-
93
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_swapchain
-
- Contact
-
-
Ian Elliott @ianelliottus
-
- Last Modified Date
-
2017-02-14
- IP Status
-
No known IP claims.
- Contributors
-
-
Ian Elliott, Google
-
Jesse Hall, Google
-
This device extension allows an application that uses the
VK_KHR_swapchain extension to obtain information about the
presentation engine’s display, to obtain timing information about each
present, and to schedule a present to happen no earlier than a desired time.
An application can use this to minimize various visual anomalies (e.g.
stuttering).
Traditional game and real-time animation applications need to correctly position their geometry for when the presentable image will be presented to the user. To accomplish this, applications need various timing information about the presentation engine’s display. They need to know when presentable images were actually presented, and when they could have been presented. Applications also need to tell the presentation engine to display an image no sooner than a given time. This allows the application to avoid stuttering, so the animation looks smooth to the user.
This extension treats variable-refresh-rate (VRR) displays as if they are fixed-refresh-rate (FRR) displays.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PRESENT_TIMES_INFO_GOOGLE
-
New Enums
None.
New Structures
Issues
None.
Examples
|
Note
The example code for the this extension (like the |
Version History
-
Revision 1, 2017-02-14 (Ian Elliott)
-
Internal revisions
-
VK_IMG_filter_cubic
- Name String
-
VK_IMG_filter_cubic - Extension Type
-
Device extension
- Registered Extension Number
-
16
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Tobias Hector @tobski
-
- Last Modified Date
-
2016-02-23
- Contributors
-
-
Tobias Hector, Imagination Technologies
-
VK_IMG_filter_cubic adds an additional, high quality cubic filtering mode
to Vulkan, using a Catmull-Rom bicubic filter.
Performing this kind of filtering can be done in a shader by using 16
samples and a number of instructions, but this can be inefficient.
The cubic filter mode exposes an optimized high quality texture sampling
using fixed texture sampling functionality.
New Enum Constants
-
Extending VkFilter:
-
VK_FILTER_CUBIC_IMG
-
-
Extending VkFormatFeatureFlagBits
-
VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_IMG
-
Example
Creating a sampler with the new filter for both magnification and minification
VkSamplerCreateInfo createInfo =
{
VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO // sType
// Other members set to application-desired values
};
createInfo.magFilter = VK_FILTER_CUBIC_IMG;
createInfo.minFilter = VK_FILTER_CUBIC_IMG;
VkSampler sampler;
VkResult result = vkCreateSampler(
device,
&createInfo,
&sampler);
Version History
-
Revision 1, 2016-02-23 (Tobias Hector)
-
Initial version
-
VK_MVK_ios_surface
- Name String
-
VK_MVK_ios_surface - Extension Type
-
Instance extension
- Registered Extension Number
-
123
- Revision
-
2
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_surface
-
- Contact
-
-
Bill Hollings @billhollings
-
- Last Modified Date
-
2017-02-24
- IP Status
-
No known IP claims.
- Contributors
-
-
Bill Hollings, The Brenwill Workshop Ltd.
-
The VK_MVK_ios_surface extension is an instance extension.
It provides a mechanism to create a VkSurfaceKHR object (defined by
the VK_KHR_surface extension) that refers to a UIView, the native
surface type of iOS, which is underpinned by a CAMetalLayer, to support
rendering to the surface using Apple’s Metal framework.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_IOS_SURFACE_CREATE_INFO_MVK
-
New Enums
None.
New Structures
New Functions
Issues
None.
Version History
-
Revision 1, 2017-02-15 (Bill Hollings)
-
Initial draft.
-
-
Revision 2, 2017-02-24 (Bill Hollings)
-
Minor syntax fix to emphasize firm requirement for UIView to be backed by a CAMetalLayer.
-
VK_MVK_macos_surface
- Name String
-
VK_MVK_macos_surface - Extension Type
-
Instance extension
- Registered Extension Number
-
124
- Revision
-
2
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_surface
-
- Contact
-
-
Bill Hollings @billhollings
-
- Last Modified Date
-
2017-02-24
- IP Status
-
No known IP claims.
- Contributors
-
-
Bill Hollings, The Brenwill Workshop Ltd.
-
The VK_MVK_macos_surface extension is an instance extension.
It provides a mechanism to create a VkSurfaceKHR object (defined by
the VK_KHR_surface extension) that refers to an NSView, the
native surface type of macOS, which is underpinned by a CAMetalLayer,
to support rendering to the surface using Apple’s Metal framework.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_MACOS_SURFACE_CREATE_INFO_MVK
-
New Enums
None.
New Structures
New Functions
Issues
None.
Version History
-
Revision 1, 2017-02-15 (Bill Hollings)
-
Initial draft.
-
-
Revision 2, 2017-02-24 (Bill Hollings)
-
Minor syntax fix to emphasize firm requirement for NSView to be backed by a CAMetalLayer.
-
VK_NN_vi_surface
- Name String
-
VK_NN_vi_surface - Extension Type
-
Instance extension
- Registered Extension Number
-
63
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_surface
-
- Contact
-
-
Mathias Heyer gitlab:@mheyer
-
- Last Modified Date
-
2016-12-02
- IP Status
-
No known IP claims.
- Contributors
-
-
Mathias Heyer, NVIDIA
-
Michael Chock, NVIDIA
-
Yasuhiro Yoshioka, Nintendo
-
Daniel Koch, NVIDIA
-
The VK_NN_vi_surface extension is an instance extension.
It provides a mechanism to create a VkSurfaceKHR object (defined by
the VK_KHR_surface extension) associated with an
nn::vi::Layer.
New Object Types
None
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_VI_SURFACE_CREATE_INFO_NN
-
New Enums
None
New Structures
New Functions
Issues
1) Does VI need a way to query for compatibility between a particular physical device (and queue family?) and a specific VI display?
RESOLVED: No. It is currently always assumed that the device and display will always be compatible.
2) VkViSurfaceCreateInfoNN::pWindow is intended to store an
nn::vi::NativeWindowHandle, but its declared type is a bare
void* to store the window handle.
Why the discrepancy?
RESOLVED: It is for C compatibility.
The definition for the VI native window handle type is defined inside the
nn::vi C++ namespace.
This prevents its use in C source files.
nn::vi::NativeWindowHandle is always defined to be
void*, so this extension uses void* to match.
Version History
-
Revision 1, 2016-12-2 (Michael Chock)
-
Initial draft.
-
VK_NV_clip_space_w_scaling
- Name String
-
VK_NV_clip_space_w_scaling - Extension Type
-
Device extension
- Registered Extension Number
-
88
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Eric Werness @ewerness-nv
-
- Last Modified Date
-
2017-02-15
- Contributors
-
-
Eric Werness, NVIDIA
-
Kedarnath Thangudu, NVIDIA
-
Virtual Reality (VR) applications often involve a post-processing step to apply a “barrel” distortion to the rendered image to correct the “pincushion” distortion introduced by the optics in a VR device. The barrel distorted image has lower resolution along the edges compared to the center. Since the original image is rendered at high resolution, which is uniform across the complete image, a lot of pixels towards the edges do not make it to the final post-processed image.
This extension provides a mechanism to render VR scenes at a non-uniform resolution, in particular a resolution that falls linearly from the center towards the edges. This is achieved by scaling the w coordinate of the vertices in the clip space before perspective divide. The clip space w coordinate of the vertices can be offset as of a function of x and y coordinates as follows:
w' = w + Ax + By
In the intended use case for viewport position scaling, an application should use a set of four viewports, one for each of the four quadrants of a Cartesian coordinate system. Each viewport is set to the dimension of the image, but is scissored to the quadrant it represents. The application should specify A and B coefficients of the w-scaling equation above, that have the same value, but different signs, for each of the viewports. The signs of A and B should match the signs of x and y for the quadrant that they represent such that the value of w' will always be greater than or equal to the original w value for the entire image. Since the offset to w, (Ax + By), is always positive, and increases with the absolute values of x and y, the effective resolution will fall off linearly from the center of the image to its edges.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_W_SCALING_STATE_CREATE_INFO_NV
-
-
Extending VkDynamicState:
-
VK_DYANMIC_STATE_VIEWPORT_W_SCALING_NV
-
New Enums
None.
New Structures
New Functions
Issues
1) Is the pipeline struct name too long?
RESOLVED: It fits with the naming convention.
2) Separate W scaling section or fold into coordinate transformations?
RESOLVED: Leaving it as its own section for now.
Examples
VkViewport viewports[4];
VkRect2D scissors[4];
VkViewportWScalingNV scalings[4];
for (int i = 0; i < 4; i++) {
int x = (i & 2) ? 0 : currentWindowWidth / 2;
int y = (i & 1) ? 0 : currentWindowHeight / 2;
viewports[i].x = 0;
viewports[i].y = 0;
viewports[i].width = currentWindowWidth;
viewports[i].height = currentWindowHeight;
viewports[i].minDepth = 0.0f;
viewports[i].maxDepth = 1.0f;
scissors[i].offset.x = x;
scissors[i].offset.y = y;
scissors[i].extent.width = currentWindowWidth/2;
scissors[i].extent.height = currentWindowHeight/2;
const float factor = 0.15;
scalings[i].xcoeff = ((i & 2) ? -1.0 : 1.0) * factor;
scalings[i].ycoeff = ((i & 1) ? -1.0 : 1.0) * factor;
}
VkPipelineViewportWScalingStateCreateInfoNV vpWScalingStateInfo = { VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_W_SCALING_STATE_CREATE_INFO_NV };
vpWScalingStateInfo.viewportWScalingEnable = VK_TRUE;
vpWScalingStateInfo.viewportCount = 4;
vpWScalingStateInfo.pViewportWScalings = &scalings[0];
VkPipelineViewportStateCreateInfo vpStateInfo = { VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO };
vpStateInfo.viewportCount = 4;
vpStateInfo.pViewports = &viewports[0];
vpStateInfo.scissorCount = 4;
vpStateInfo.pScissors = &scissors[0];
vpStateInfo.pNext = &vpWScalingStateInfo;
Example shader to read from a w-scaled texture:
// Vertex Shader
// Draw a triangle that covers the whole screen
const vec4 positions[3] = vec4[3](vec4(-1, -1, 0, 1),
vec4( 3, -1, 0, 1),
vec4(-1, 3, 0, 1));
out vec2 uv;
void main()
{
vec4 pos = positions[ gl_VertexID ];
gl_Position = pos;
uv = pos.xy;
}
// Fragment Shader
uniform sampler2D tex;
uniform float xcoeff;
uniform float ycoeff;
out vec4 Color;
in vec2 uv;
void main()
{
// Handle uv as if upper right quadrant
vec2 uvabs = abs(uv);
// unscale: transform w-scaled image into an unscaled image
// scale: transform unscaled image int a w-scaled image
float unscale = 1.0 / (1 + xcoeff * uvabs.x + xcoeff * uvabs.y);
//float scale = 1.0 / (1 - xcoeff * uvabs.x - xcoeff * uvabs.y);
vec2 P = vec2(unscale * uvabs.x, unscale * uvabs.y);
// Go back to the right quadrant
P *= sign(uv);
Color = texture(tex, P * 0.5 + 0.5);
}
Version History
-
Revision 1, 2017-02-15 (Eric Werness)
-
Internal revisions
-
VK_NV_dedicated_allocation
- Name String
-
VK_NV_dedicated_allocation - Extension Type
-
Device extension
- Registered Extension Number
-
27
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Jeff Bolz @jeffbolznv
-
- Last Modified Date
-
2016-05-31
- IP Status
-
No known IP claims.
- Contributors
-
-
Jeff Bolz, NVIDIA
-
This extension allows device memory to be allocated for a particular buffer or image resource, which on some devices can significantly improve the performance of that resource. Normal device memory allocations must support memory aliasing and sparse binding, which could interfere with optimizations like framebuffer compression or efficient page table usage. This is important for render targets and very large resources, but need not (and probably should not) be used for smaller resources that can benefit from suballocation.
This extension adds a few small structures to resource creation and memory allocation: a new structure that flags whether am image/buffer will have a dedicated allocation, and a structure indicating the image or buffer that an allocation will be bound to.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_IMAGE_CREATE_INFO_NV -
VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_BUFFER_CREATE_INFO_NV -
VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_MEMORY_ALLOCATE_INFO_NV
-
New Enums
None.
New Structures
New Functions
None.
Issues
None.
Examples
// Create an image with
// VkDedicatedAllocationImageCreateInfoNV::dedicatedAllocation
// set to VK_TRUE
VkDedicatedAllocationImageCreateInfoNV dedicatedImageInfo =
{
VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_IMAGE_CREATE_INFO_NV, // sType
NULL, // pNext
VK_TRUE, // dedicatedAllocation
};
VkImageCreateInfo imageCreateInfo =
{
VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO, // sType
&dedicatedImageInfo // pNext
// Other members set as usual
};
VkImage image;
VkResult result = vkCreateImage(
device,
&imageCreateInfo,
NULL, // pAllocator
&image);
VkMemoryRequirements memoryRequirements;
vkGetImageMemoryRequirements(
device,
image,
&memoryRequirements);
// Allocate memory with VkDedicatedAllocationMemoryAllocateInfoNV::image
// pointing to the image we are allocating the memory for
VkDedicatedAllocationMemoryAllocateInfoNV dedicatedInfo =
{
VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_MEMORY_ALLOCATE_INFO_NV, // sType
NULL, // pNext
image, // image
VK_NULL_HANDLE, // buffer
};
VkMemoryAllocateInfo memoryAllocateInfo =
{
VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO, // sType
&dedicatedInfo, // pNext
memoryRequirements.size, // allocationSize
FindMemoryTypeIndex(memoryRequirements.memoryTypeBits), // memoryTypeIndex
};
VkDeviceMemory memory;
vkAllocateMemory(
device,
&memoryAllocateInfo,
NULL, // pAllocator
&memory);
// Bind the image to the memory
vkBindImageMemory(
device,
image,
memory,
0);
Version History
-
Revision 1, 2016-05-31 (Jeff Bolz)
-
Internal revisions
-
VK_NV_external_memory_capabilities
- Name String
-
VK_NV_external_memory_capabilities - Extension Type
-
Instance extension
- Registered Extension Number
-
56
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2016-08-19
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
Interacts with Vulkan 1.1.
-
Interacts with
VK_KHR_dedicated_allocation. -
Interacts with
VK_NV_dedicated_allocation.
-
- Contributors
-
-
James Jones, NVIDIA
-
Applications may wish to import memory from the Direct 3D API, or export memory to other Vulkan instances. This extension provides a set of capability queries that allow applications determine what types of win32 memory handles an implementation supports for a given set of use cases.
New Object Types
None.
New Enum Constants
None.
New Structs
New Functions
Issues
1) Why do so many external memory capabilities need to be queried on a per-memory-handle-type basis?
RESOLVED: This is because some handle types are based on OS-native objects that have far more limited capabilities than the very generic Vulkan memory objects. Not all memory handle types can name memory objects that support 3D images, for example. Some handle types cannot even support the deferred image and memory binding behavior of Vulkan and require specifying the image when allocating or importing the memory object.
2) Does the VkExternalImageFormatPropertiesNV struct need to include a list of memory type bits that support the given handle type?
RESOLVED: No. The memory types that do not support the handle types will simply be filtered out of the results returned by vkGetImageMemoryRequirements when a set of handle types was specified at image creation time.
3) Should the non-opaque handle types be moved to their own extension?
RESOLVED: Perhaps. However, defining the handle type bits does very little and does not require any platform-specific types on its own, and it is easier to maintain the bitmask values in a single extension for now. Presumably more handle types could be added by separate extensions though, and it would be midly weird to have some platform-specific ones defined in the core spec and some in extensions
VK_NV_external_memory
- Name String
-
VK_NV_external_memory - Extension Type
-
Device extension
- Registered Extension Number
-
57
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_NV_external_memory_capabilities
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2016-08-19
- IP Status
-
No known IP claims.
- Contributors
-
-
James Jones, NVIDIA
-
Carsten Rohde, NVIDIA
-
Applications may wish to export memory to other Vulkan instances or other APIs, or import memory from other Vulkan instances or other APIs to enable Vulkan workloads to be split up across application module, process, or API boundaries. This extension enables applications to create exportable Vulkan memory objects such that the underlying resources can be referenced outside the Vulkan instance that created them.
New Object Types
None.
New Enum Constants
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO_NV -
VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO_NV
New Enums
None.
New Structures
New Functions
None.
Issues
1) If memory objects are shared between processes and APIs, is this considered aliasing according to the rules outlined in the Memory Aliasing section?
RESOLVED: Yes, but strict exceptions to the rules are added to allow some forms of aliasing in these cases. Further, other extensions may build upon these new aliasing rules to define specific support usage within Vulkan for imported native memory objects, or memory objects from other APIs.
2) Are new image layouts or metadata required to specify image layouts and layout transitions compatible with non-Vulkan APIs, or with other instances of the same Vulkan driver?
RESOLVED: No.
Separate instances of the same Vulkan driver running on the same GPU should
have identical internal layout semantics, so applictions have the tools they
need to ensure views of images are consistent between the two instances.
Other APIs will fall into two categories: Those that are Vulkan compatible
(a term to be defined by subsequent interopability extensions), or Vulkan
incompatible.
When sharing images with Vulkan incompatible APIs, the Vulkan image must be
transitioned to the VK_IMAGE_LAYOUT_GENERAL layout before handing it
off to the external API.
Note this does not attempt to address cross-device transitions, nor transitions to engines on the same device which are not visible within the Vulkan API. Both of these are beyond the scope of this extension.
Examples
// TODO: Write some sample code here.
Version History
-
Revision 1, 2016-08-19 (James Jones)
-
Initial draft
-
VK_NV_external_memory_win32
- Name String
-
VK_NV_external_memory_win32 - Extension Type
-
Device extension
- Registered Extension Number
-
58
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_NV_external_memory
-
- Contact
-
-
James Jones @cubanismo
-
- Last Modified Date
-
2016-08-19
- IP Status
-
No known IP claims.
- Contributors
-
-
James Jones, NVIDIA
-
Carsten Rohde, NVIDIA
-
Applications may wish to export memory to other Vulkan instances or other APIs, or import memory from other Vulkan instances or other APIs to enable Vulkan workloads to be split up across application module, process, or API boundaries. This extension enables win32 applications to export win32 handles from Vulkan memory objects such that the underlying resources can be referenced outside the Vulkan instance that created them, and import win32 handles created in the Direct3D API to Vulkan memory objects.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_IMPORT_MEMORY_WIN32_HANDLE_INFO_NV -
VK_STRUCTURE_TYPE_EXPORT_MEMORY_WIN32_HANDLE_INFO_NV
-
New Enums
None.
New Structures
New Functions
Issues
1) If memory objects are shared between processes and APIs, is this considered aliasing according to the rules outlined in the Memory Aliasing section?
RESOLVED: Yes, but strict exceptions to the rules are added to allow some forms of aliasing in these cases. Further, other extensions may build upon these new aliasing rules to define specific support usage within Vulkan for imported native memory objects, or memory objects from other APIs.
2) Are new image layouts or metadata required to specify image layouts and layout transitions compatible with non-Vulkan APIs, or with other instances of the same Vulkan driver?
RESOLVED: No.
Separate instances of the same Vulkan driver running on the same GPU should
have identical internal layout semantics, so applictions have the tools they
need to ensure views of images are consistent between the two instances.
Other APIs will fall into two categories: Those that are Vulkan compatible
(a term to be defined by subsequent interopability extensions), or Vulkan
incompatible.
When sharing images with Vulkan incompatible APIs, the Vulkan image must be
transitioned to the VK_IMAGE_LAYOUT_GENERAL layout before handing it
off to the external API.
Note this does not attempt to address cross-device transitions, nor transitions to engines on the same device which are not visible within the Vulkan API. Both of these are beyond the scope of this extension.
3) Do applications need to call CloseHandle() on the values returned
from vkGetMemoryWin32HandleNV when handleType is
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_NV?
RESOLVED: Yes, unless it is passed back in to another driver instance to import the object. A successful get call transfers ownership of the handle to the application, while an import transfers ownership to the associated driver. Destroying the memory object will not destroy the handle or the handle’s reference to the underlying memory resource.
Examples
//
// Create an exportable memory object and export an external
// handle from it.
//
// Pick an external format and handle type.
static const VkFormat format = VK_FORMAT_R8G8B8A8_UNORM;
static const VkExternalMemoryHandleTypeFlagsNV handleType =
VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_NV;
extern VkPhysicalDevice physicalDevice;
extern VkDevice device;
VkPhysicalDeviceMemoryProperties memoryProperties;
VkExternalImageFormatPropertiesNV properties;
VkExternalMemoryImageCreateInfoNV externalMemoryImageCreateInfo;
VkDedicatedAllocationImageCreateInfoNV dedicatedImageCreateInfo;
VkImageCreateInfo imageCreateInfo;
VkImage image;
VkMemoryRequirements imageMemoryRequirements;
uint32_t numMemoryTypes;
uint32_t memoryType;
VkExportMemoryAllocateInfoNV exportMemoryAllocateInfo;
VkDedicatedAllocationMemoryAllocateInfoNV dedicatedAllocationInfo;
VkMemoryAllocateInfo memoryAllocateInfo;
VkDeviceMemory memory;
VkResult result;
HANDLE memoryHnd;
// Figure out how many memory types the device supports
vkGetPhysicalDeviceMemoryProperties(physicalDevice,
&memoryProperties);
numMemoryTypes = memoryProperties.memoryTypeCount;
// Check the external handle type capabilities for the chosen format
// Exportable 2D image support with at least 1 mip level, 1 array
// layer, and VK_SAMPLE_COUNT_1_BIT using optimal tiling and supporting
// texturing and color rendering is required.
result = vkGetPhysicalDeviceExternalImageFormatPropertiesNV(
physicalDevice,
format,
VK_IMAGE_TYPE_2D,
VK_IMAGE_TILING_OPTIMAL,
VK_IMAGE_USAGE_SAMPLED_BIT |
VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT,
0,
handleType,
&properties);
if ((result != VK_SUCCESS) ||
!(properties.externalMemoryFeatures &
VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT_NV)) {
abort();
}
// Set up the external memory image creation info
memset(&externalMemoryImageCreateInfo,
0, sizeof(externalMemoryImageCreateInfo));
externalMemoryImageCreateInfo.sType =
VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO_NV;
externalMemoryImageCreateInfo.handleTypes = handleType;
if (properties.externalMemoryFeatures &
VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT_NV) {
memset(&dedicatedImageCreateInfo, 0, sizeof(dedicatedImageCreateInfo));
dedicatedImageCreateInfo.sType =
VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_IMAGE_CREATE_INFO_NV;
dedicatedImageCreateInfo.dedicatedAllocation = VK_TRUE;
externalMemoryImageCreateInfo.pNext = &dedicatedImageCreateInfo;
}
// Set up the core image creation info
memset(&imageCreateInfo, 0, sizeof(imageCreateInfo));
imageCreateInfo.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO;
imageCreateInfo.pNext = &externalMemoryImageCreateInfo;
imageCreateInfo.format = format;
imageCreateInfo.extent.width = 64;
imageCreateInfo.extent.height = 64;
imageCreateInfo.extent.depth = 1;
imageCreateInfo.mipLevels = 1;
imageCreateInfo.arrayLayers = 1;
imageCreateInfo.samples = VK_SAMPLE_COUNT_1_BIT;
imageCreateInfo.tiling = VK_IMAGE_TILING_OPTIMAL;
imageCreateInfo.usage = VK_IMAGE_USAGE_SAMPLED_BIT |
VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;
imageCreateInfo.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
imageCreateInfo.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
vkCreateImage(device, &imageCreateInfo, NULL, &image);
vkGetImageMemoryRequirements(device,
image,
&imageMemoryRequirements);
// For simplicity, just pick the first compatible memory type.
for (memoryType = 0; memoryType < numMemoryTypes; memoryType++) {
if ((1 << memoryType) & imageMemoryRequirements.memoryTypeBits) {
break;
}
}
// At least one memory type must be supported given the prior external
// handle capability check.
assert(memoryType < numMemoryTypes);
// Allocate the external memory object.
memset(&exportMemoryAllocateInfo, 0, sizeof(exportMemoryAllocateInfo));
exportMemoryAllocateInfo.sType =
VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO_NV;
exportMemoryAllocateInfo.handleTypes = handleType;
if (properties.externalMemoryFeatures &
VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT_NV) {
memset(&dedicatedAllocationInfo, 0, sizeof(dedicatedAllocationInfo));
dedicatedAllocationInfo.sType =
VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_MEMORY_ALLOCATE_INFO_NV;
dedicatedAllocationInfo.image = image;
exportMemoryAllocateInfo.pNext = &dedicatedAllocationInfo;
}
memset(&memoryAllocateInfo, 0, sizeof(memoryAllocateInfo));
memoryAllocateInfo.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
memoryAllocateInfo.pNext = &exportMemoryAllocateInfo;
memoryAllocateInfo.allocationSize = imageMemoryRequirements.size;
memoryAllocateInfo.memoryTypeIndex = memoryType;
vkAllocateMemory(device, &memoryAllocateInfo, NULL, &memory);
if (!(properties.externalMemoryFeatures &
VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT_NV)) {
vkBindImageMemory(device, image, memory, 0);
}
// Get the external memory opaque FD handle
vkGetMemoryWin32HandleNV(device, memory, &memoryHnd);
Version History
-
Revision 1, 2016-08-11 (James Jones)
-
Initial draft
-
VK_NV_fill_rectangle
- Name String
-
VK_NV_fill_rectangle - Extension Type
-
Device extension
- Registered Extension Number
-
154
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Jeff Bolz @jeffbolznv
-
- Last Modified Date
-
2017-05-22
- Contributors
-
-
Jeff Bolz, NVIDIA
-
This extension adds a new VkPolygonMode enum where a triangle is
rasterized by computing and filling its axis-aligned screen-space bounding
box, disregarding the actual triangle edges.
This can be useful for drawing a rectangle without being split into two
triangles with an internal edge.
It is also useful to minimize the number of primitives that need to be
drawn, particularly for a user interface.
New Object Types
None.
New Enum Constants
-
Extending VkPolygonMode
-
VK_POLYGON_MODE_FILL_RECTANGLE_NV
-
New Enums
None.
New Structures
None.
New Functions
None.
Issues
None.
Version History
-
Revision 1, 2017-05-22 (Jeff Bolz)
-
Internal revisions
-
VK_NV_fragment_coverage_to_color
- Name String
-
VK_NV_fragment_coverage_to_color - Extension Type
-
Device extension
- Registered Extension Number
-
150
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Jeff Bolz @jeffbolznv
-
- Last Modified Date
-
2017-05-21
- Contributors
-
-
Jeff Bolz, NVIDIA
-
This extension allows the fragment coverage value, represented as an integer
bitmask, to be substituted for a color output being written to a
single-component color attachment with integer components (e.g.
VK_FORMAT_R8_UINT).
The functionality provided by this extension is different from simply
writing the SampleMask fragment shader output, in that the coverage
value written to the framebuffer is taken after stencil test and depth test,
as well as after fragment operations such as alpha-to-coverage.
This functionality may be useful for deferred rendering algorithms, where the second pass needs to know which samples belong to which original fragments.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PIPELINE_COVERAGE_TO_COLOR_STATE_CREATE_INFO_NV
-
New Structures
New Functions
None.
Issues
None.
Version History
-
Revision 1, 2017-05-21 (Jeff Bolz)
-
Internal revisions
-
VK_NV_framebuffer_mixed_samples
- Name String
-
VK_NV_framebuffer_mixed_samples - Extension Type
-
Device extension
- Registered Extension Number
-
153
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Jeff Bolz @jeffbolznv
-
- Last Modified Date
-
2017-06-04
- Contributors
-
-
Jeff Bolz, NVIDIA
-
This extension allows multisample rendering with a raster and depth/stencil sample count that is larger than the color sample count. Rasterization and the results of the depth and stencil tests together determine the portion of a pixel that is “covered”. It can be useful to evaluate coverage at a higher frequency than color samples are stored. This coverage is then “reduced” to a collection of covered color samples, each having an opacity value corresponding to the fraction of the color sample covered. The opacity can optionally be blended into individual color samples.
Rendering with fewer color samples than depth/stencil samples greatly reduces the amount of memory and bandwidth consumed by the color buffer. However, converting the coverage values into opacity introduces artifacts where triangles share edges and may not be suitable for normal triangle mesh rendering.
One expected use case for this functionality is Stencil-then-Cover path rendering (similar to the OpenGL GL_NV_path_rendering extension). The stencil step determines the coverage (in the stencil buffer) for an entire path at the higher sample frequency, and then the cover step draws the path into the lower frequency color buffer using the coverage information to antialias path edges. With this two-step process, internal edges are fully covered when antialiasing is applied and there is no corruption on these edges.
The key features of this extension are:
-
It allows render pass and framebuffer objects to be created where the number of samples in the depth/stencil attachment in a subpass is a multiple of the number of samples in the color attachments in the subpass.
-
A coverage reduction step is added to Fragment Operations which converts a set of covered raster/depth/stencil samples to a set of color samples that perform blending and color writes. The coverage reduction step also includes an optional coverage modulation step, multiplying color values by a fractional opacity corresponding to the number of associated raster/depth/stencil samples covered.
New Object Types
None.
New Enum Constants
None.
New Structures
New Functions
None.
Issues
None.
Version History
-
Revision 1, 2017-06-04 (Jeff Bolz)
-
Internal revisions
-
VK_NV_geometry_shader_passthrough
- Name String
-
VK_NV_geometry_shader_passthrough - Extension Type
-
Device extension
- Registered Extension Number
-
96
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Daniel Koch @dgkoch
-
- Last Modified Date
-
2017-02-15
- Interactions and External Dependencies
-
-
This extension requires the SPV_NV_geometry_shader_passthrough SPIR-V extension.
-
This extension requires the GL_NV_geometry_shader_passthrough extension for GLSL source languages.
-
This extension requires the
geometryShaderfeature.
-
- Contributors
-
-
Piers Daniell, NVIDIA
-
Jeff Bolz, NVIDIA
-
This extension adds support for the following SPIR-V extension in Vulkan:
-
SPV_NV_geometry_shader_passthrough
Geometry shaders provide the ability for applications to process each
primitive sent through the graphics pipeline using a programmable shader.
However, one common use case treats them largely as a “passthrough”.
In this use case, the bulk of the geometry shader code simply copies inputs
from each vertex of the input primitive to corresponding outputs in the
vertices of the output primitive.
Such shaders might also compute values for additional built-in or
user-defined per-primitive attributes (e.g., Layer) to be assigned to
all the vertices of the output primitive.
This extension provides access to the PassthroughNV decoration under
the GeometryShaderPassthroughNV capability.
Adding this to a geometry shader input variable specifies that the values of
this input are copied to the corresponding vertex of the output primitive.
When using GLSL source-based shading languages, the passthrough layout
qualifier from GL_NV_geometry_shader_passthrough maps to the
PassthroughNV decoration.
To use the passthrough layout, in GLSL the
GL_NV_geometry_shader_passthrough extension must be enabled.
Behaviour is described in the GL_NV_geometry_shader_passthrough extension
specification.
New Object Types
None.
New Enum Constants
None.
New Enums
None.
New Structures
None.
New Functions
None.
New Built-In Variables
None.
New Variable Decoration
New SPIR-V Capabilities
Issues
1) Should we require or allow a passthrough geometry shader to specify the output layout qualifiers for the output primitive type and maximum vertex count in the SPIR-V?
RESOLVED: Yes they should be required in the SPIR-V. Per GL_NV_geometry_shader_passthrough they are not permitted in the GLSL source shader, but SPIR-V is lower-level. It is straightforward for the GLSL compiler to infer them from the input primitive type and to explicitly emit them in the SPIR-V according to the following table.
| Input Layout | Implied Output Layout |
|---|---|
points |
|
lines |
|
triangles |
|
2) How does interface matching work with passthrough geometry shaders?
RESOLVED: This is described in Passthrough Interface Matching.
In GL when using passthough geometry shaders in separable mode, all inputs
must also be explicitly assigned location layout qualifiers.
In Vulkan all SPIR-V shader inputs (except built-ins) must also have
location decorations specified.
Redeclarations of built-in varables that add the passthrough layout
qualifier are exempted from the rule requiring location assignment because
built-in variables do not have locations and are matched by BuiltIn
decoration.
Sample Code
Consider the following simple geometry shader in unextended GLSL:
layout(triangles) in;
layout(triangle_strip) out;
layout(max_vertices=3) out;
in Inputs {
vec2 texcoord;
vec4 baseColor;
} v_in[];
out Outputs {
vec2 texcoord;
vec4 baseColor;
};
void main()
{
int layer = compute_layer();
for (int i = 0; i < 3; i++) {
gl_Position = gl_in[i].gl_Position;
texcoord = v_in[i].texcoord;
baseColor = v_in[i].baseColor;
gl_Layer = layer;
EmitVertex();
}
}
In this shader, the inputs gl_Position, Inputs.texcoord, and
Inputs.baseColor are simply copied from the input vertex to the
corresponding output vertex.
The only “interesting” work done by the geometry shader is computing and
emitting a gl_Layer value for the primitive.
The following geometry shader, using this extension, is equivalent:
#extension GL_NV_geometry_shader_passthrough : require
layout(triangles) in;
// No output primitive layout qualifiers required.
// Redeclare gl_PerVertex to pass through "gl_Position".
layout(passthrough) in gl_PerVertex {
vec4 gl_Position;
} gl_in[];
// Declare "Inputs" with "passthrough" to automatically copy members.
layout(passthrough) in Inputs {
vec2 texcoord;
vec4 baseColor;
} v_in[];
// No output block declaration required.
void main()
{
// The shader simply computes and writes gl_Layer. We don't
// loop over three vertices or call EmitVertex().
gl_Layer = compute_layer();
}
Version History
-
Revision 1, 2017-02-15 (Daniel Koch)
-
Internal revisions
-
VK_NV_glsl_shader
- Name String
-
VK_NV_glsl_shader - Extension Type
-
Device extension
- Registered Extension Number
-
13
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Piers Daniell @pdaniell-nv
-
- Last Modified Date
-
2016-02-14
- IP Status
-
No known IP claims.
- Contributors
-
-
Piers Daniell, NVIDIA
-
This extension allows GLSL shaders written to the GL_KHR_vulkan_glsl extension specification to be used instead of SPIR-V. The implementation will automatically detect whether the shader is SPIR-V or GLSL, and compile it appropriately.
New Object Types
New Enum Constants
-
Extending VkResult:
-
VK_ERROR_INVALID_SHADER_NV
-
New Enums
New Structures
New Functions
Issues
Examples
Example 1
Passing in GLSL code
char const vss[] =
"#version 450 core\n"
"layout(location = 0) in vec2 aVertex;\n"
"layout(location = 1) in vec4 aColor;\n"
"out vec4 vColor;\n"
"void main()\n"
"{\n"
" vColor = aColor;\n"
" gl_Position = vec4(aVertex, 0, 1);\n"
"}\n"
;
VkShaderModuleCreateInfo vertexShaderInfo = { VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO };
vertexShaderInfo.codeSize = sizeof vss;
vertexShaderInfo.pCode = vss;
VkShaderModule vertexShader;
vkCreateShaderModule(device, &vertexShaderInfo, 0, &vertexShader);
Version History
-
Revision 1, 2016-02-14 (Piers Daniell)
-
Initial draft
-
VK_NV_sample_mask_override_coverage
- Name String
-
VK_NV_sample_mask_override_coverage - Extension Type
-
Device extension
- Registered Extension Number
-
95
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Piers Daniell @pdaniell-nv
-
- Last Modified Date
-
2016-12-08
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
This extension requires the SPV_NV_sample_mask_override_coverage SPIR-V extension.
-
This extension requires the GL_NV_sample_mask_override_coverage extension for GLSL source languages.
-
- Contributors
-
-
Daniel Koch, NVIDIA
-
Jeff Bolz, NVIDIA
-
This extension adds support for the following SPIR-V extension in Vulkan:
-
SPV_NV_sample_mask_override_coverage
The extension provides access to the OverrideCoverageNV decoration
under the SampleMaskOverrideCoverageNV capability.
Adding this decoration to a variable with the SampleMask builtin
decoration allows the shader to modify the coverage mask and affect which
samples are used to process the fragment.
When using GLSL source-based shader languages, the override_coverage
layout qualifier from GL_NV_sample_mask_override_coverage maps to the
OverrideCoverageNV decoration.
To use the override_coverage layout qualifier in GLSL the
GL_NV_sample_mask_override_coverage extension must be enabled.
Behavior is described in the GL_NV_sample_mask_override_coverage extension
spec.
New Object Types
None.
New Enum Constants
None.
New Enums
None.
New Structures
None.
New Functions
None.
New Built-In Variables
None.
New Variable Decoration
New SPIR-V Capabilities
Issues
None.
Version History
-
Revision 1, 2016-12-08 (Piers Daniell)
-
Internal revisions
-
VK_NV_shader_subgroup_partitioned
- Name String
-
VK_NV_shader_subgroup_partitioned - Extension Type
-
Device extension
- Registered Extension Number
-
199
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.1
-
- Contact
-
-
Jeff Bolz @jeffbolznv
-
- Last Modified Date
-
2018-03-17
- Contributors
-
-
Jeff Bolz, NVIDIA
-
This extension enables support for a new class of subgroup operations via
the
GL_NV_shader_subgroup_partitioned
GLSL extension and
SPV_NV_shader_subgroup_partitioned
SPIR-V extension.
Support for these new operations is advertised via the
VK_SUBGROUP_FEATURE_PARTITIONED_BIT_NV bit.
This extension requires Vulkan 1.1, for general subgroup support.
New Object Types
None.
New Enum Constants
-
Extending VkSubgroupFeatureFlagBits:
-
VK_SUBGROUP_FEATURE_PARTITIONED_BIT_NV
-
New Enums
None.
New Structures
None.
New Functions
None.
Issues
None.
Version History
-
Revision 1, 2018-03-17 (Jeff Bolz)
-
Internal revisions
-
VK_NV_viewport_array2
- Name String
-
VK_NV_viewport_array2 - Extension Type
-
Device extension
- Registered Extension Number
-
97
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Daniel Koch @dgkoch
-
- Last Modified Date
-
2017-02-15
- Interactions and External Dependencies
-
-
This extension requires the SPV_NV_viewport_array2 SPIR-V extension.
-
This extension requires the GL_NV_viewport_array2 extension for GLSL source languages.
-
This extension requires the
geometryShaderandmultiViewportfeatures. -
This extension interacts with the
tessellationShaderfeature.
-
- Contributors
-
-
Piers Daniell, NVIDIA
-
Jeff Bolz, NVIDIA
-
This extension adds support for the following SPIR-V extension in Vulkan:
-
SPV_NV_viewport_array2
which allows a single primitive to be broadcast to multiple viewports and/or
multiple layers.
A new shader built-in output ViewportMaskNV is provided, which allows a
single primitive to be output to multiple viewports simultaneously.
Also, a new SPIR-V decoration is added to control whether the effective
viewport index is added into the variable decorated with the Layer
built-in decoration.
These capabilities allow a single primitive to be output to multiple layers
simultaneously.
This extension allows variables decorated with the Layer and
ViewportIndex built-ins to be exported from vertex or tessellation
shaders, using the ShaderViewportIndexLayerNV capability.
This extension adds a new ViewportMaskNV built-in decoration that is
available for output variables in vertex, tessellation evaluation, and
geometry shaders, and a new ViewportRelativeNV decoration that can be
added on variables decorated with Layer when using the
ShaderViewportMaskNV capability.
When using GLSL source-based shading languages, the gl_ViewportMask[]
built-in output variable and viewport_relative layout qualifier from
GL_NV_viewport_array2 map to the ViewportMaskNV and
ViewportRelativeNV decorations, respectively.
Behaviour is described in the GL_NV_viewport_array2 extension
specificiation.
|
Note
The |
New Object Types
None.
New Enum Constants
None.
New Enums
None.
New Structures
None.
New Functions
None.
New or Modified Built-In Variables
-
(modified)
Layer -
(modified)
ViewportIndex
New Variable Decoration
New SPIR-V Capabilities
Issues
None yet!
Version History
-
Revision 1, 2017-02-15 (Daniel Koch)
-
Internal revisions
-
VK_NV_viewport_swizzle
- Name String
-
VK_NV_viewport_swizzle - Extension Type
-
Device extension
- Registered Extension Number
-
99
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Piers Daniell @pdaniell-nv
-
- Last Modified Date
-
2016-12-22
- Interactions and External Dependencies
-
-
This extension requires
multiViewportandgeometryShaderfeatures to be useful.
-
- Contributors
-
-
Daniel Koch, NVIDIA
-
Jeff Bolz, NVIDIA
-
This extension provides a new per-viewport swizzle that can modify the position of primitives sent to each viewport. New viewport swizzle state is added for each viewport, and a new position vector is computed for each vertex by selecting from and optionally negating any of the four components of the original position vector.
This new viewport swizzle is useful for a number of algorithms, including single-pass cubemap rendering (broadcasting a primitive to multiple faces and reorienting the vertex position for each face) and voxel rasterization. The per-viewport component remapping and negation provided by the swizzle allows application code to re-orient three-dimensional geometry with a view along any of the X, Y, or Z axes. If a perspective projection and depth buffering is required, 1/W buffering should be used, as described in the single-pass cubemap rendering example in the “Issues” section below.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_SWIZZLE_STATE_CREATE_INFO_NV
-
New Structures
New Functions
None.
Issues
1) Where does viewport swizzling occur in the pipeline?
RESOLVED: Despite being associated with the viewport, viewport swizzling must happen prior to the viewport transform. In particular, it needs to be performed before clipping and perspective division.
The viewport mask expansion (VK_NV_viewport_array2) and the viewport
swizzle could potentially be performed before or after transform feedback,
but feeding back several viewports worth of primitives with different
swizzles doesn’t seem particularly useful.
This specification applies the viewport mask and swizzle after transform
feedback, and makes primitive queries only count each primitive once.
2) Any interesting examples of how this extension,
VK_NV_viewport_array2, and VK_NV_geometry_shader_passthrough can
be used together in practice?
RESOLVED: One interesting use case for this extension is for single-pass
rendering to a cubemap.
In this example, the application would attach a cubemap texture to a layered
FBO where the six cube faces are treated as layers.
Vertices are sent through the vertex shader without applying a projection
matrix, where the gl_Position output is (x,y,z,1) and the center
of the cubemap is at (0,0,0).
With unextended Vulkan, one could have a conventional instanced geometry
shader that looks something like the following:
layout(invocations = 6) in; // separate invocation per face
layout(triangles) in;
layout(triangle_strip) out;
layout(max_vertices = 3) out;
in Inputs {
vec2 texcoord;
vec3 normal;
vec4 baseColor;
} v[];
out Outputs {
vec2 texcoord;
vec3 normal;
vec4 baseColor;
};
void main()
{
int face = gl_InvocationID; // which face am I?
// Project gl_Position for each vertex onto the cube map face.
vec4 positions[3];
for (int i = 0; i < 3; i++) {
positions[i] = rotate(gl_in[i].gl_Position, face);
}
// If the primitive doesn't project onto this face, we're done.
if (shouldCull(positions)) {
return;
}
// Otherwise, emit a copy of the input primitive to the
// appropriate face (using gl_Layer).
for (int i = 0; i < 3; i++) {
gl_Layer = face;
gl_Position = positions[i];
texcoord = v[i].texcoord;
normal = v[i].normal;
baseColor = v[i].baseColor;
EmitVertex();
}
}
With passthrough geometry shaders, this can be done using a much simpler shader:
layout(triangles) in;
layout(passthrough) in Inputs {
vec2 texcoord;
vec3 normal;
vec4 baseColor;
}
layout(passthrough) in gl_PerVertex {
vec4 gl_Position;
} gl_in[];
layout(viewport_relative) out int gl_Layer;
void main()
{
// Figure out which faces the primitive projects onto and
// generate a corresponding viewport mask.
uint mask = 0;
for (int i = 0; i < 6; i++) {
if (!shouldCull(face)) {
mask |= 1U << i;
}
}
gl_ViewportMask = mask;
gl_Layer = 0;
}
The application code is set up so that each of the six cube faces has a
separate viewport (numbered 0 to 5).
Each face also has a separate swizzle, programmed via the
VkPipelineViewportSwizzleStateCreateInfoNV pipeline state.
The viewport swizzle feature performs the coordinate transformation handled
by the rotate() function in the original shader.
The viewport_relative layout qualifier says that the viewport number (0
to 5) is added to the base gl_Layer value of 0 to determine which layer
(cube face) the primitive should be sent to.
Note that the use of the passed through input normal in this example
suggests that the fragment shader in this example would perform an operation
like per-fragment lighting.
The viewport swizzle would transform the position to be face-relative, but
normal would remain in the original coordinate system.
It seems likely that the fragment shader in either version of the example
would want to perform lighting in the original coordinate system.
It would likely do this by reconstructing the position of the fragment in
the original coordinate system using gl_FragCoord, a constant or
uniform holding the size of the cube face, and the input
gl_ViewportIndex (or gl_Layer), which identifies the cube face.
Since the value of normal is in the original coordinate system, it
would not need to be modified as part of this coordinate transformation.
Note that while the rotate() operation in the regular geometry shader
above could include an arbitrary post-rotation projection matrix, the
viewport swizzle does not support arbitrary math.
To get proper projection, 1/W buffering should be used.
To do this:
1. Program the viewport swizzles to move the pre-projection W eye coordinate (typically 1.0) into the Z coordinate of the swizzle output and the eye coordinate component used for depth into the W coordinate. For example, the viewport corresponding to the +Z face might use a swizzle of (+X, -Y, +W, +Z). The Z normalized device coordinate computed after swizzling would then be z'/w' = 1/Zeye.
2.
On NVIDIA implementations supporting floating-point depth buffers with
values outside [0,1], prevent unwanted near plane clipping by enabling
depthClampEnable.
Ensure that the depth clamp doesn’t mess up depth testing by programming the
depth range to very large values, such as minDepthBounds=-z,
maxDepthBounds=+z, where z = 2127.
It should be possible to use IEEE infinity encodings also (0xFF800000 for
-INF, 0x7F800000 for +INF).
Even when near/far clipping is disabled, primitives extending behind the eye
will still be clipped because one or more vertices will have a negative
W coordinate and fail X/Y clipping tests.
On other implementations, scale X, Y, and Z eye coordinates so that vertices on the near plane have a post-swizzle W coordinate of 1.0. For example, if the near plane is at Zeye = 1/256, scale X, Y, and Z by 256.
3.
Adjust depth testing to reflect the fact that 1/W values are large
near the eye and small away from the eye.
Clear the depth buffer to zero (infinitely far away) and use a depth test of
VK_COMPARE_OP_GREATER instead of VK_COMPARE_OP_LESS.
Version History
-
Revision 1, 2016-12-22 (Piers Daniell)
-
Internal revisions
-
VK_NV_win32_keyed_mutex
- Name String
-
VK_NV_win32_keyed_mutex - Extension Type
-
Device extension
- Registered Extension Number
-
59
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_NV_external_memory_win32
-
- Contact
-
-
Carsten Rohde @crohde
-
- Last Modified Date
-
2016-08-19
- IP Status
-
No known IP claims.
- Contributors
-
-
James Jones, NVIDIA
-
Carsten Rohde, NVIDIA
-
Applications that wish to import Direct3D 11 memory objects into the Vulkan API may wish to use the native keyed mutex mechanism to synchronize access to the memory between Vulkan and Direct3D. This extension provides a way for an application to access the keyed mutex associated with an imported Vulkan memory object when submitting command buffers to a queue.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_WIN32_KEYED_MUTEX_ACQUIRE_RELEASE_INFO_NV
-
New Enums
None.
New Structures
New Functions
None.
Issues
None.
Examples
//
// Import a memory object from Direct3D 11, and synchronize
// access to it in Vulkan using keyed mutex objects.
//
extern VkPhysicalDevice physicalDevice;
extern VkDevice device;
extern HANDLE sharedNtHandle;
static const VkFormat format = VK_FORMAT_R8G8B8A8_UNORM;
static const VkExternalMemoryHandleTypeFlagsNV handleType =
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_IMAGE_BIT_NV;
VkPhysicalDeviceMemoryProperties memoryProperties;
VkExternalImageFormatPropertiesNV properties;
VkExternalMemoryImageCreateInfoNV externalMemoryImageCreateInfo;
VkImageCreateInfo imageCreateInfo;
VkImage image;
VkMemoryRequirements imageMemoryRequirements;
uint32_t numMemoryTypes;
uint32_t memoryType;
VkImportMemoryWin32HandleInfoNV importMemoryInfo;
VkMemoryAllocateInfo memoryAllocateInfo;
VkDeviceMemory mem;
VkResult result;
// Figure out how many memory types the device supports
vkGetPhysicalDeviceMemoryProperties(physicalDevice,
&memoryProperties);
numMemoryTypes = memoryProperties.memoryTypeCount;
// Check the external handle type capabilities for the chosen format
// Importable 2D image support with at least 1 mip level, 1 array
// layer, and VK_SAMPLE_COUNT_1_BIT using optimal tiling and supporting
// texturing and color rendering is required.
result = vkGetPhysicalDeviceExternalImageFormatPropertiesNV(
physicalDevice,
format,
VK_IMAGE_TYPE_2D,
VK_IMAGE_TILING_OPTIMAL,
VK_IMAGE_USAGE_SAMPLED_BIT |
VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT,
0,
handleType,
&properties);
if ((result != VK_SUCCESS) ||
!(properties.externalMemoryFeatures &
VK_EXTERNAL_MEMORY_FEATURE_IMPORTABLE_BIT_NV)) {
abort();
}
// Set up the external memory image creation info
memset(&externalMemoryImageCreateInfo,
0, sizeof(externalMemoryImageCreateInfo));
externalMemoryImageCreateInfo.sType =
VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO_NV;
externalMemoryImageCreateInfo.handleTypes = handleType;
// Set up the core image creation info
memset(&imageCreateInfo, 0, sizeof(imageCreateInfo));
imageCreateInfo.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO;
imageCreateInfo.pNext = &externalMemoryImageCreateInfo;
imageCreateInfo.format = format;
imageCreateInfo.extent.width = 64;
imageCreateInfo.extent.height = 64;
imageCreateInfo.extent.depth = 1;
imageCreateInfo.mipLevels = 1;
imageCreateInfo.arrayLayers = 1;
imageCreateInfo.samples = VK_SAMPLE_COUNT_1_BIT;
imageCreateInfo.tiling = VK_IMAGE_TILING_OPTIMAL;
imageCreateInfo.usage = VK_IMAGE_USAGE_SAMPLED_BIT |
VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;
imageCreateInfo.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
imageCreateInfo.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
vkCreateImage(device, &imageCreateInfo, NULL, &image);
vkGetImageMemoryRequirements(device,
image,
&imageMemoryRequirements);
// For simplicity, just pick the first compatible memory type.
for (memoryType = 0; memoryType < numMemoryTypes; memoryType++) {
if ((1 << memoryType) & imageMemoryRequirements.memoryTypeBits) {
break;
}
}
// At least one memory type must be supported given the prior external
// handle capability check.
assert(memoryType < numMemoryTypes);
// Allocate the external memory object.
memset(&exportMemoryAllocateInfo, 0, sizeof(exportMemoryAllocateInfo));
exportMemoryAllocateInfo.sType =
VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO_NV;
importMemoryInfo.handleTypes = handleType;
importMemoryInfo.handle = sharedNtHandle;
memset(&memoryAllocateInfo, 0, sizeof(memoryAllocateInfo));
memoryAllocateInfo.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
memoryAllocateInfo.pNext = &exportMemoryAllocateInfo;
memoryAllocateInfo.allocationSize = imageMemoryRequirements.size;
memoryAllocateInfo.memoryTypeIndex = memoryType;
vkAllocateMemory(device, &memoryAllocateInfo, NULL, &mem);
vkBindImageMemory(device, image, mem, 0);
...
const uint64_t acquireKey = 1;
const uint32_t timeout = INFINITE;
const uint64_t releaseKey = 2;
VkWin32KeyedMutexAcquireReleaseInfoNV keyedMutex =
{ VK_STRUCTURE_TYPE_WIN32_KEYED_MUTEX_ACQUIRE_RELEASE_INFO_NV };
keyedMutex.acquireCount = 1;
keyedMutex.pAcquireSyncs = &mem;
keyedMutex.pAcquireKeys = &acquireKey;
keyedMutex.pAcquireTimeoutMilliseconds = &timeout;
keyedMutex.releaseCount = 1;
keyedMutex.pReleaseSyncs = &mem;
keyedMutex.pReleaseKeys = &releaseKey;
VkSubmitInfo submit_info = { VK_STRUCTURE_TYPE_SUBMIT_INFO, &keyedMutex };
submit_info.commandBufferCount = 1;
submit_info.pCommandBuffers = &cmd_buf;
vkQueueSubmit(queue, 1, &submit_info, VK_NULL_HANDLE);
Version History
-
Revision 2, 2016-08-11 (James Jones)
-
Updated sample code based on the NV external memory extensions.
-
Renamed from NVX to NV extension.
-
Added Overview and Description sections.
-
Updated sample code to use the NV external memory extensions.
-
-
Revision 1, 2016-06-14 (Carsten Rohde)
-
Initial draft.
-
VK_NVX_device_generated_commands
- Name String
-
VK_NVX_device_generated_commands - Extension Type
-
Device extension
- Registered Extension Number
-
87
- Revision
-
3
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
- Contact
-
-
Christoph Kubisch @pixeljetstream
-
- Last Modified Date
-
2017-07-25
- Contributors
-
-
Pierre Boudier, NVIDIA
-
Christoph Kubisch, NVIDIA
-
Mathias Schott, NVIDIA
-
Jeff Bolz, NVIDIA
-
Eric Werness, NVIDIA
-
Detlef Roettger, NVIDIA
-
Daniel Koch, NVIDIA
-
Chris Hebert, NVIDIA
-
This extension allows the device to generate a number of critical commands for command buffers.
When rendering a large number of objects, the device can be leveraged to implement a number of critical functions, like updating matrices, or implementing occlusion culling, frustum culling, front to back sorting, etc. Implementing those on the device does not require any special extension, since an application is free to define its own data structure, and just process them using shaders.
However, if the application desires to quickly kick off the rendering of the final stream of objects, then unextended Vulkan forces the application to read back the processed stream and issue graphics command from the host. For very large scenes, the synchronization overhead, and cost to generate the command buffer can become the bottleneck. This extension allows an application to generate a device side stream of state changes and commands, and convert it efficiently into a command buffer without having to read it back on the host.
Furthermore, it allows incremental changes to such command buffers by manipulating only partial sections of a command stream — for example pipeline bindings. Unextended Vulkan requires re-creation of entire command buffers in such scenario, or updates synchronized on the host.
The intended usage for this extension is for the application to:
-
create its objects as in unextended Vulkan
-
create a VkObjectTableNVX, and register the various Vulkan objects that are needed to evaluate the input parameters.
-
create a VkIndirectCommandsLayoutNVX, which lists the VkIndirectCommandsTokenTypeNVX it wants to dynamically change as atomic command sequence. This step likely involves some internal device code compilation, since the intent is for the GPU to generate the command buffer in the pipeline.
-
fill the input buffers with the data for each of the inputs it needs. Each input is an array that will be filled with an index in the object table, instead of using CPU pointers.
-
set up a target secondary command buffer
-
reserve command buffer space via vkCmdReserveSpaceForCommandsNVX in a target command buffer at the position you want the generated commands to be executed.
-
call vkCmdProcessCommandsNVX to create the actual device commands for all sequences based on the array contents into a provided target command buffer.
-
execute the target command buffer like a regular secondary command buffer
For each draw/dispatch, the following can be specified:
-
a different pipeline state object
-
a number of descriptor sets, with dynamic offsets
-
a number of vertex buffer bindings, with an optional dynamic offset
-
a different index buffer, with an optional dynamic offset
Applications should register a small number of objects, and use dynamic offsets whenever possible.
While the GPU can be faster than a CPU to generate the commands, it may not happen asynchronously, therefore the primary use-case is generating “less” total work (occlusion culling, classification to use specialized shaders, etc.).
New Object Types
New Flag Types
New Enum Constants
Extending VkStructureType:
-
VK_STRUCTURE_TYPE_OBJECT_TABLE_CREATE_INFO_NVX -
VK_STRUCTURE_TYPE_INDIRECT_COMMANDS_LAYOUT_CREATE_INFO_NVX -
VK_STRUCTURE_TYPE_CMD_PROCESS_COMMANDS_INFO_NVX -
VK_STRUCTURE_TYPE_CMD_RESERVE_SPACE_FOR_COMMANDS_INFO_NVX -
VK_STRUCTURE_TYPE_DEVICE_GENERATED_COMMANDS_LIMITS_NVX -
VK_STRUCTURE_TYPE_DEVICE_GENERATED_COMMANDS_FEATURES_NVX
Extending VkPipelineStageFlagBits:
-
VK_PIPELINE_STAGE_COMMAND_PROCESS_BIT_NVX
Extending VkAccessFlagBits:
-
VK_ACCESS_COMMAND_PROCESS_READ_BIT_NVX -
VK_ACCESS_COMMAND_PROCESS_WRITE_BIT_NVX
New Enums
New Structures
New Functions
Issues
1) How to name this extension ?
RESOLVED: VK_NVX_device_generated_commands
As usual, one of the hardest issues ;)
Alternatives: VK_gpu_commands, VK_execute_commands,
VK_device_commands, VK_device_execute_commands, VK_device_execute,
VK_device_created_commands, VK_device_recorded_commands,
VK_device_generated_commands
2) Should we use serial tokens or redundant sequence description?
Similarly to VkPipeline, signatures have the most likelihood to be cross-vendor adoptable. They also benefit from being processable in parallel.
3) How to name sequence description
ExecuteCommandSignature is a bit long.
Maybe just ExecuteSignature, or actually more following Vulkan
nomenclature: VkIndirectCommandsLayoutNVX.
4) Do we want to provide indirectCommands inputs with layout or at
indirectCommands time?
Separate layout from data as Vulkan does.
Provide full flexibilty for indirectCommands.
5) Should the input be provided as SoA or AoS?
It is desirable for the application to reuse the list of objects and render them with some kind of an override. This can be done by just selecting a different input for a push constant or a descriptor set, if they are defined as independent arrays. If the data was interleaved, this would not be as easily possible.
Allowing input divisors can also reduce the conservative command buffer allocation.
6) How do we know the size of the GPU command buffer generated by vkCmdProcessCommandsNVX ?
maxSequenceCount can give an upper estimate, even if the actual count
is sourced from the gpu buffer at (buffer, countOffset).
As such maxSequenceCount must always be set correctly.
Developers are encouraged to make well use the
VkIndirectCommandsLayoutNVX’s pTokens[].divisor, as they allow
less conservative storage costs.
Especially pipeline changes on a per-draw basis can be costly memory wise.
7) How to deal with dynamic offsets in DescriptorSets?
Maybe additional token VK_EXECUTE_DESCRIPTOR_SET_OFFSET_COMMAND_NVX
that works for a “single dynamic buffer” descriptor set and then use (32
bit tableEntry + 32bit offset)
added dynamicCount field, variable sized input
8) Should we allow updates to the object table, similar to DescriptorSet?
Desired yes, people may change “material” shaders and not want to recreate the entire register table. However the developer must ensure to not overwrite a registered objectIndex while it is still being used.
9) Should we allow dynamic state changes?
Seems a bit excessive for “per-draw” type of scenario, but GPU could partition work itself with viewport/scissor…
10) How do we allow re-using already “filled” indirectCommands
buffers?
just use a VkCommandBuffer for the output, and it can be reused easily.
11) How portable should such re-use be?
Same as secondary command buffer
12) Should sequenceOrdered be part of IndirectCommandsLayout or vkCmdProcessCommandsNVX?
Seems better for IndirectCommandsLayout, as that is when most heavy lifting in terms of internal device code generation is done.
13) Under which conditions is vkCmdProcessCommandsNVX legal?
Options:
a) on the host command buffer like a regular draw call
b) vkCmdProcessCommandsNVX makes use VkCommandBufferBeginInfo and serves as vkBeginCommandBuffer / vkEndCommandBuffer implicitly.
c) The targetCommandbuffer must be inside the “begin” state already
at the moment of being passed.
This very likely suggests a new VkCommandBufferUsageFlags
VK_COMMAND_BUFFER_USAGE_DEVICE_GENERATED_BIT.
d) The targetCommandbuffer must reserve space via a new function.
used a) and d).
14) What if different pipelines have different DescriptorSetLayouts at a
certain set unit that mismatches in token.dynamicCount?
Considered legal, as long as the maximum dynamic count of all used DescriptorSetLayouts is provided.
15) Should we add “strides” to input arrays, so that “Array of Structures” type setups can be supported more easily?
Maybe provide a usage flag for packed tokens stream (all inputs from same buffer, implicit stride).
No, given performance test was worse.
16) Should we allow re-using the target command buffer directly, without need to reset command buffer?
YES: new api vkCmdReserveSpaceForCommandsNVX.
17) Is vkCmdProcessCommandsNVX copying the input data or referencing it ?
There are multiple implementations possible:
-
one could have some emulation code that parse the inputs, and generates an output command buffer, therefore copying the inputs.
-
one could just reference the inputs, and have the processing done in pipe at execution time.
If the data is mandated to be copied, then it puts a penalty on implementation that could process the inputs directly in pipe. If the data is “referenced”, then it allows both types of implementation
The inputs are “referenced”, and should not be modified after the call to vkCmdProcessCommandsNVX and until after the rendering of the target command buffer is finished.
18) Why is this NVX and not NV?
To allow early experimentation and feedback. We expect that a version with a refined design as multi-vendor variant will follow up.
19) Should we make the availability for each token type a device limit?
Only distinguish between graphics/compute for now, further splitting up may lead to too much fractioning.
20) When can the objectTable be modified?
Similar to the other inputs for vkCmdProcessCommandsNVX, only when all device access via vkCmdProcessCommandsNVX or execution of target command buffer has completed can an object at a given objectIndex be unregistered or re-registered again.
21) Which buffer usage flags are required for the buffers referenced by vkCmdProcessCommandsNVX
reuse existing VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT
-
VkCmdProcessCommandsInfoNVX::
sequencesCountBuffer -
VkCmdProcessCommandsInfoNVX::
sequencesIndexBuffer -
VkIndirectCommandsTokenNVX::
buffer
22) In which pipeline stage do the device generated command expansion happen?
vkCmdProcessCommandsNVX is treated as if it occurs in a separate
logical pipeline from either graphics or compute, and that pipeline only
includes VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT, a new stage
VK_PIPELINE_STAGE_COMMAND_PROCESS_BIT_NVX, and
VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT.
This new stage has two corresponding new access types,
VK_ACCESS_COMMAND_PROCESS_READ_BIT_NVX and
VK_ACCESS_COMMAND_PROCESS_WRITE_BIT_NVX, used to synchronize reading
the buffer inputs and writing the command buffer memory output.
The output written in the target command buffer is considered to be consumed
by the VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT pipeline stage.
Thus, to synchronize from writing the input buffers to executing vkCmdProcessCommandsNVX, use:
-
dstStageMask=VK_PIPELINE_STAGE_COMMAND_PROCESS_BIT_NVX -
dstAccessMask=VK_ACCESS_COMMAND_PROCESS_READ_BIT_NVX
To synchronize from executing vkCmdProcessCommandsNVX to executing the generated commands, use
-
srcStageMask=VK_PIPELINE_STAGE_COMMAND_PROCESS_BIT_NVX -
srcAccessMask=VK_ACCESS_COMMAND_PROCESS_WRITE_BIT_NVX -
dstStageMask=VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT -
dstAccessMask=VK_ACCESS_INDIRECT_COMMAND_READ_BIT
When vkCmdProcessCommandsNVX is used with a targetCommandBuffer
of NULL, the generated commands are immediately executed and there is
implicit synchronization between generation and execution.
23) What if most token data is “static”, but we frequently want to render a subsection?
added “sequencesIndexBuffer”. This allows to easier sort and filter what should actually be processed.
Example Code
Open-Source samples illustrating the usage of the extension can be found at the following locations:
// setup secondary command buffer
vkBeginCommandBuffer(generatedCmdBuffer, &beginInfo);
... setup its state as usual
// insert the reservation (there can only be one per command buffer)
// where the generated calls should be filled into
VkCmdReserveSpaceForCommandsInfoNVX reserveInfo = { VK_STRUCTURE_TYPE_CMD_RESERVE_SPACE_FOR_COMMANDS_INFO_NVX };
reserveInfo.objectTable = objectTable;
reserveInfo.indirectCommandsLayout = deviceGeneratedLayout;
reserveInfo.maxSequencesCount = myCount;
vkCmdReserveSpaceForCommandsNVX(generatedCmdBuffer, &reserveInfo);
vkEndCommandBuffer(generatedCmdBuffer);
// trigger the generation at some point in another primary command buffer
VkCmdProcessCommandsInfoNVX processInfo = { VK_STRUCTURE_TYPE_CMD_PROCESS_COMMANDS_INFO_NVX };
processInfo.objectTable = objectTable;
processInfo.indirectCommandsLayout = deviceGeneratedLayout;
processInfo.maxSequencesCount = myCount;
// set the target of the generation (if null we would directly execute with mainCmd)
processInfo.targetCommandBuffer = generatedCmdBuffer;
// provide input data
processInfo.indirectCommandsTokenCount = 3;
processInfo.pIndirectCommandsTokens = myTokens;
// If you modify the input buffer data referenced by VkCmdProcessCommandsInfoNVX,
// ensure you have added the appropriate barriers prior generation process.
// When regenerating the content of the same reserved space, ensure prior operations have completed
VkMemoryBarrier memoryBarrier = { VK_STRUCTURE_TYPE_MEMORY_BARRIER };
memoryBarrier.srcAccessMask = ...;
memoryBarrier.dstAccessMask = VK_ACCESS_COMMAND_PROCESS_READ_BIT_NVX;
vkCmdPipelineBarrier(mainCmd,
/*srcStageMask*/VK_PIPELINE_STAGE_ALL_COMMANDS_BIT,
/*dstStageMask*/VK_PIPELINE_STAGE_COMMAND_PROCESS_BIT_NVX,
/*dependencyFlags*/0,
/*memoryBarrierCount*/1,
/*pMemoryBarriers*/&memoryBarrier,
...);
vkCmdProcessCommandsNVX(mainCmd, &processInfo);
...
// execute the secondary command buffer and ensure the processing that modifies command-buffer content
// has completed
memoryBarrier.srcAccessMask = VK_ACCESS_COMMAND_PROCESS_WRITE_BIT_NVX;
memoryBarrier.dstAccessMask = VK_ACCESS_INDIRECT_COMMAND_READ_BIT;
vkCmdPipelineBarrier(mainCmd,
/*srcStageMask*/VK_PIPELINE_STAGE_COMMAND_PROCESS_BIT_NVX,
/*dstStageMask*/VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT,
/*dependencyFlags*/0,
/*memoryBarrierCount*/1,
/*pMemoryBarriers*/&memoryBarrier,
...)
vkCmdExecuteCommands(mainCmd, 1, &generatedCmdBuffer);
Version History
-
Revision 3, 2017-07-25 (Chris Hebert)
-
Correction to specification of dynamicCount for push_constant token in VkIndirectCommandsLayoutNVX. Stride was incorrectly computed as dynamicCount was not treated as byte size.
-
-
Revision 2, 2017-06-01 (Christoph Kubisch)
-
header compatibility break: add missing _TYPE to VkIndirectCommandsTokenTypeNVX and VkObjectEntryTypeNVX enums to follow Vulkan naming convention
-
behavior clarification: only allow a single work provoking token per sequence when creating a VkIndirectCommandsLayoutNVX
-
-
Revision 1, 2016-10-31 (Christoph Kubisch)
-
Initial draft
-
VK_NVX_multiview_per_view_attributes
- Name String
-
VK_NVX_multiview_per_view_attributes - Extension Type
-
Device extension
- Registered Extension Number
-
98
- Revision
-
1
- Extension and Version Dependencies
-
-
Requires Vulkan 1.0
-
Requires
VK_KHR_multiview
-
- Contact
-
-
Jeff Bolz @jeffbolznv
-
- Last Modified Date
-
2017-01-13
- IP Status
-
No known IP claims.
- Interactions and External Dependencies
-
-
This extension requires the SPV_NVX_multiview_per_view_attributes SPIR-V extension.
-
This extension requires the GL_NVX_multiview_per_view_attributes extension for GLSL source languages.
-
This extension interacts with
VK_NV_viewport_array2.
-
- Contributors
-
-
Jeff Bolz, NVIDIA
-
Daniel Koch, NVIDIA
-
This extension adds a new way to write shaders to be used with multiview subpasses, where the attributes for all views are written out by a single invocation of the vertex processing stages. Related SPIR-V and GLSL extensions SPV_NVX_multiview_per_view_attributes and GL_NVX_multiview_per_view_attributes introduce per-view position and viewport mask attributes arrays, and this extension defines how those per-view attribute arrays are interpreted by Vulkan. Pipelines using per-view attributes may only execute the vertex processing stages once for all views rather than once per-view, which reduces redundant shading work.
A subpass creation flag controls whether the subpass uses this extension. A subpass must either exclusively use this extension or not use it at all.
Some Vulkan implementations only support the position attribute varying between views in the X component. A subpass can declare via a second creation flag whether all pipelines compiled for this subpass will obey this restriction.
Shaders that use the new per-view outputs (e.g. gl_PositionPerViewNV)
must also write the non-per-view output (gl_Position), and the values
written must be such that gl_Position =
gl_PositionPerViewNV[gl_ViewIndex] for all views in the subpass.
Implementations are free to either use the per-view outputs or the
non-per-view outputs, whichever would be more efficient.
If VK_NV_viewport_array2 is not also supported and enabled, the
per-view viewport mask must not be used.
New Object Types
None.
New Enum Constants
-
Extending VkStructureType
-
VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PER_VIEW_ATTRIBUTES_PROPERTIES_NVX
-
-
Extending VkSubpassDescriptionFlagBits
-
VK_SUBPASS_DESCRIPTION_PER_VIEW_ATTRIBUTES_BIT_NVX -
VK_SUBPASS_DESCRIPTION_PER_VIEW_POSITION_X_ONLY_BIT_NVX
-
New Enums
None.
New Structures
New Functions
None.
New Built-In Variables
New SPIR-V Capabilities
Issues
None.
Examples
#version 450 core
#extension GL_KHX_multiview : enable
#extension GL_NVX_multiview_per_view_attributes : enable
layout(location = 0) in vec4 position;
layout(set = 0, binding = 0) uniform Block { mat4 mvpPerView[2]; } buf;
void main()
{
// Output both per-view positions and gl_Position as a function
// of gl_ViewIndex
gl_PositionPerViewNV[0] = buf.mvpPerView[0] * position;
gl_PositionPerViewNV[1] = buf.mvpPerView[1] * position;
gl_Position = buf.mvpPerView[gl_ViewIndex] * position;
}
Version History
-
Revision 1, 2017-01-13 (Jeff Bolz)
-
Internal revisions
-
Appendix E: API Boilerplate
This appendix defines Vulkan API features that are infrastructure required for a complete functional description of Vulkan, but do not logically belong elsewhere in the Specification.
Vulkan Header Files
Vulkan is defined as an API in the C99 language.
Khronos provides a corresponding set of header files for applications using
the API, which may be used in either C or C++ code.
The interface descriptions in the specification are the same as the
interfaces defined in these header files, and both are derived from the
vk.xml XML API Registry, which is the canonical machine-readable
description of the Vulkan API.
The Registry, scripts used for processing it into various forms, and
documentation of the registry schema are available as described at
https://www.khronos.org/registry/vulkan/#apiregistry .
Language bindings for other languages can be defined using the information in the Specification and the Registry. Khronos does not provide any such bindings, but third-party developers have created some additional bindings.
Vulkan Combined API Header vulkan.h (Informative)
Applications normally will include the header vulkan.h.
In turn, vulkan.h always includes the following headers:
-
vk_platform.h, defining platform-specific macros and headers. -
vulkan_core.h, defining APIs for the Vulkan core and all registered extensions other than window system-specific extensions.
In addition, specific preprocessor macros defined at the time vulkan.h is
included cause header files for the corresponding window system-specific extension interfaces to be included.
Vulkan Platform-Specific Header vk_platform.h (Informative)
Platform-specific macros and interfaces are defined in vk_platform.h.
These macros are used to control platform-dependent behavior, and their
exact definitions are under the control of specific platforms and Vulkan
implementations.
Platform-Specific Calling Conventions
On many platforms the following macros are empty strings, causing platform- and compiler-specific default calling conventions to be used.
VKAPI_ATTR is a macro placed before the return type in Vulkan API
function declarations.
This macro controls calling conventions for C++11 and GCC/Clang-style
compilers.
VKAPI_CALL is a macro placed after the return type in Vulkan API
function declarations.
This macro controls calling conventions for MSVC-style compilers.
VKAPI_PTR is a macro placed between the '(' and '*' in Vulkan API
function pointer declarations.
This macro also controls calling conventions, and typically has the same
definition as VKAPI_ATTR or VKAPI_CALL, depending on the
compiler.
With these macros, a Vulkan function declaration takes the form of:
VKAPI_ATTR <return_type> VKAPI_CALL <command_name>(<command_parameters>);
Additionaly, a Vulkan function pointer type declaration takes the form of:
typedef <return_type> (VKAPI_PTR *PFN_<command_name>)(<command_parameters>);
Platform-Specific Header Control
If the VK_NO_STDINT_H macro is defined by the application at compile
time, extended integer types used by the Vulkan API, such as uint8_t,
must also be defined by the application.
Otherwise, the Vulkan headers will not compile.
If VK_NO_STDINT_H is not defined, the system <stdint.h> is used to
define these types.
There is a fallback path when Microsoft Visual Studio version 2008 and
earlier versions are detected at compile time.
Vulkan Core API Header vulkan_core.h
Applications that do not make use of window system-specific extensions may
simply include vulkan_core.h instead of vulkan.h, although there is
usually no reason to do so.
In addition to the Vulkan API, vulkan_core.h also defines a small number
of C preprocessor macros that are described below.
Vulkan Version Number Macros
API Version Numbers are packed into integers. These macros manipulate version numbers in useful ways.
VK_VERSION_MAJOR extracts the API major version number from a packed
version number:
#define VK_VERSION_MAJOR(version) ((uint32_t)(version) >> 22)
VK_VERSION_MINOR extracts the API minor version number from a packed
version number:
#define VK_VERSION_MINOR(version) (((uint32_t)(version) >> 12) & 0x3ff)
VK_VERSION_PATCH extracts the API patch version number from a packed
version number:
#define VK_VERSION_PATCH(version) ((uint32_t)(version) & 0xfff)
VK_API_VERSION_1_0 returns the API version number for Vulkan 1.0.
The patch version number in this macro will always be zero.
The supported patch version for a physical device can be queried with
vkGetPhysicalDeviceProperties.
// Vulkan 1.0 version number
#define VK_API_VERSION_1_0 VK_MAKE_VERSION(1, 0, 0)// Patch version should always be set to 0
VK_API_VERSION_1_1 returns the API version number for Vulkan 1.1.
The patch version number in this macro will always be zero.
The supported patch version for a physical device can be queried with
vkGetPhysicalDeviceProperties.
// Vulkan 1.1 version number
#define VK_API_VERSION_1_1 VK_MAKE_VERSION(1, 1, 0)// Patch version should always be set to 0
VK_API_VERSION is now commented out of vulkan_core.h and cannot be
used.
// DEPRECATED: This define has been removed. Specific version defines (e.g. VK_API_VERSION_1_0), or the VK_MAKE_VERSION macro, should be used instead.
//#define VK_API_VERSION VK_MAKE_VERSION(1, 0, 0) // Patch version should always be set to 0
VK_MAKE_VERSION constructs an API version number.
#define VK_MAKE_VERSION(major, minor, patch) \
(((major) << 22) | ((minor) << 12) | (patch))
-
majoris the major version number. -
minoris the minor version number. -
patchis the patch version number.
This macro can be used when constructing the
VkApplicationInfo::apiVersion parameter passed to
vkCreateInstance.
Vulkan Header File Version Number
VK_HEADER_VERSION is the version number of the vulkan_core.h header.
This value is kept synchronized with the patch version of the released
Specification.
// Version of this file
#define VK_HEADER_VERSION 76
Vulkan Handle Macros
VK_DEFINE_HANDLE defines a dispatchable handle type.
#define VK_DEFINE_HANDLE(object) typedef struct object##_T* object;
-
objectis the name of the resulting C type.
The only dispatchable handle types are those related to device and instance management, such as VkDevice.
VK_DEFINE_NON_DISPATCHABLE_HANDLE defines a
non-dispatchable handle type.
#if !defined(VK_DEFINE_NON_DISPATCHABLE_HANDLE)
#if defined(__LP64__) || defined(_WIN64) || (defined(__x86_64__) && !defined(__ILP32__) ) || defined(_M_X64) || defined(__ia64) || defined (_M_IA64) || defined(__aarch64__) || defined(__powerpc64__)
#define VK_DEFINE_NON_DISPATCHABLE_HANDLE(object) typedef struct object##_T *object;
#else
#define VK_DEFINE_NON_DISPATCHABLE_HANDLE(object) typedef uint64_t object;
#endif
#endif
-
objectis the name of the resulting C type.
Most Vulkan handle types, such as VkBuffer, are non-dispatchable.
|
Note
The |
VK_NULL_HANDLE is a reserved value representing a non-valid object
handle.
It may be passed to and returned from Vulkan commands only when
specifically allowed.
#define VK_NULL_HANDLE 0
Window System-Specific Header Control (Informative)
To use a Vulkan extension supporting a platform-specific window system, header files for that window systems must be included at compile time, or platform-specific types must be forward-declared. The Vulkan header files cannot determine whether or not an external header is available at compile time, so platform-specific extensions are provided in separate headers from the core API and platform-independent extensions, allowing applications to decide which ones should be defined and how the external headers are included.
Extensions dependent on particular sets of platform headers, or that
forward-declare platform-specific types, are declared in a header named for
that platform.
Before including these platform-specific Vulkan headers, applications must
include both vulkan_core.h and any external native headers the platform
extensions depend on.
As a convenience for applications that do not need the flexibility of
separate platform-specific Vulkan headers, vulkan.h includes
vulkan_core.h, and then conditionally includes platform-specific Vulkan
headers and the external headers they depend on.
Applications control which platform-specific headers are included by
#defining macros before including vulkan.h.
The correspondence between platform-specific extensions, external headers
they require, the platform-specific header which declares them, and the
preprocessor macros which enable inclusion by vulkan.h are shown in the
following table.
| Extension Name | Window System Name | Platform-specific Header | Required External Headers | Controlling vulkan.h Macro |
|---|---|---|---|---|
Android |
|
None |
|
|
Mir |
|
|
|
|
Wayland |
|
|
|
|
|
Microsoft Windows |
|
|
|
X11 Xcb |
|
|
|
|
X11 Xlib |
|
|
|
|
X11 XRAndR |
|
|
|
|
iOS |
|
None |
|
|
macOS |
|
None |
|
|
VI |
|
None |
|
|
Note
This section describes the purpose of the headers independently of the specific underlying functionality of the window system extensions themselves. Each extension name will only link to a description of that extension when viewing a specification built with that extension included. |
Appendix F: Invariance
The Vulkan specification is not pixel exact. It therefore does not guarantee an exact match between images produced by different Vulkan implementations. However, the specification does specify exact matches, in some cases, for images produced by the same implementation. The purpose of this appendix is to identify and provide justification for those cases that require exact matches.
Repeatability
The obvious and most fundamental case is repeated issuance of a series of Vulkan commands. For any given Vulkan and framebuffer state vector, and for any Vulkan command, the resulting Vulkan and framebuffer state must be identical whenever the command is executed on that initial Vulkan and framebuffer state. This repeatability requirement does not apply when using shaders containing side effects (image and buffer variable stores and atomic operations), because these memory operations are not guaranteed to be processed in a defined order.
The repeatability requirement does not apply for rendering done using a
graphics pipeline that uses VK_RASTERIZATION_ORDER_RELAXED_AMD.
One purpose of repeatability is avoidance of visual artifacts when a double-buffered scene is redrawn. If rendering is not repeatable, swapping between two buffers rendered with the same command sequence may result in visible changes in the image. Such false motion is distracting to the viewer. Another reason for repeatability is testability.
Repeatability, while important, is a weak requirement. Given only repeatability as a requirement, two scenes rendered with one (small) polygon changed in position might differ at every pixel. Such a difference, while within the law of repeatability, is certainly not within its spirit. Additional invariance rules are desirable to ensure useful operation.
Multi-pass Algorithms
Invariance is necessary for a whole set of useful multi-pass algorithms. Such algorithms render multiple times, each time with a different Vulkan mode vector, to eventually produce a result in the framebuffer. Examples of these algorithms include:
-
“Erasing” a primitive from the framebuffer by redrawing it, either in a different color or using the XOR logical operation.
-
Using stencil operations to compute capping planes.
Invariance Rules
For a given Vulkan device:
Rule 1 For any given Vulkan and framebuffer state vector, and for any given Vulkan command, the resulting Vulkan and framebuffer state must be identical each time the command is executed on that initial Vulkan and framebuffer state.
Rule 2 Changes to the following state values have no side effects (the use of any other state value is not affected by the change):
Required:
-
Color and depth/stencil attachment contents
-
Scissor parameters (other than enable)
-
Write masks (color, depth, stencil)
-
Clear values (color, depth, stencil)
Strongly suggested:
-
Stencil parameters (other than enable)
-
Depth test parameters (other than enable)
-
Blend parameters (other than enable)
-
Logical operation parameters (other than enable)
Corollary 1 Fragment generation is invariant with respect to the state values listed in Rule 2.
Rule 3 The arithmetic of each per-fragment operation is invariant except with respect to parameters that directly control it.
Corollary 2 Images rendered into different color attachments of the same framebuffer, either simultaneously or separately using the same command sequence, are pixel identical.
Rule 4 Identical pipelines will produce the same result when run multiple times with the same input. The wording “Identical pipelines” means VkPipeline objects that have been created with identical SPIR-V binaries and identical state, which are then used by commands executed using the same Vulkan state vector. Invariance is relaxed for shaders with side effects, such as performing stores or atomics.
Rule 5 All fragment shaders that either conditionally or unconditionally
assign FragCoord.z to FragDepth are depth-invariant with
respect to each other, for those fragments where the assignment to
FragDepth actually is done.
If a sequence of Vulkan commands specifies primitives to be rendered with shaders containing side effects (image and buffer variable stores and atomic operations), invariance rules are relaxed. In particular, rule 1, corollary 2, and rule 4 do not apply in the presence of shader side effects.
The following weaker versions of rules 1 and 4 apply to Vulkan commands involving shader side effects:
Rule 6 For any given Vulkan and framebuffer state vector, and for any given Vulkan command, the contents of any framebuffer state not directly or indirectly affected by results of shader image or buffer variable stores or atomic operations must be identical each time the command is executed on that initial Vulkan and framebuffer state.
Rule 7 Identical pipelines will produce the same result when run multiple times with the same input as long as:
-
shader invocations do not use image atomic operations;
-
no framebuffer memory is written to more than once by image stores, unless all such stores write the same value; and
-
no shader invocation, or other operation performed to process the sequence of commands, reads memory written to by an image store.
|
Note
The OpenGL spec has the following invariance rule: Consider a primitive p' obtained by translating a primitive p through an offset (x, y) in window coordinates, where x and y are integers. As long as neither p' nor p is clipped, it must be the case that each fragment f' produced from p' is identical to a corresponding fragment f from p except that the center of f' is offset by (x, y) from the center of f. This rule does not apply to Vulkan and is an intentional difference from OpenGL. |
When any sequence of Vulkan commands triggers shader invocations that perform image stores or atomic operations, and subsequent Vulkan commands read the memory written by those shader invocations, these operations must be explicitly synchronized.
Tessellation Invariance
When using a pipeline containing tessellation evaluation shaders, the fixed-function tessellation primitive generator consumes the input patch specified by an application and emits a new set of primitives. The following invariance rules are intended to provide repeatability guarantees. Additionally, they are intended to allow an application with a carefully crafted tessellation evaluation shader to ensure that the sets of triangles generated for two adjacent patches have identical vertices along shared patch edges, avoiding “cracks” caused by minor differences in the positions of vertices along shared edges.
Rule 1 When processing two patches with identical outer and inner tessellation levels, the tessellation primitive generator will emit an identical set of point, line, or triangle primitives as long as the pipeline used to process the patch primitives has tessellation evaluation shaders specifying the same tessellation mode, spacing, vertex order, and point mode decorations. Two sets of primitives are considered identical if and only if they contain the same number and type of primitives and the generated tessellation coordinates for the vertex numbered m of the primitive numbered n are identical for all values of m and n.
Rule 2 The set of vertices generated along the outer edge of the subdivided primitive in triangle and quad tessellation, and the tessellation coordinates of each, depends only on the corresponding outer tessellation level and the spacing decorations in the tessellation shaders of the pipeline.
Rule 3 The set of vertices generated when subdividing any outer primitive edge is always symmetric. For triangle tessellation, if the subdivision generates a vertex with tessellation coordinates of the form (0, x, 1-x), (x, 0, 1-x), or (x, 1-x, 0), it will also generate a vertex with coordinates of exactly (0, 1-x, x), (1-x, 0, x), or (1-x, x, 0), respectively. For quad tessellation, if the subdivision generates a vertex with coordinates of (x, 0) or (0, x), it will also generate a vertex with coordinates of exactly (1-x, 0) or (0, 1-x), respectively. For isoline tessellation, if it generates vertices at (0, x) and (1, x) where x is not zero, it will also generate vertices at exactly (0, 1-x) and (1, 1-x), respectively.
Rule 4 The set of vertices generated when subdividing outer edges in triangular and quad tessellation must be independent of the specific edge subdivided, given identical outer tessellation levels and spacing. For example, if vertices at (x, 1 - x, 0) and (1-x, x, 0) are generated when subdividing the w = 0 edge in triangular tessellation, vertices must be generated at (x, 0, 1-x) and (1-x, 0, x) when subdividing an otherwise identical v = 0 edge. For quad tessellation, if vertices at (x, 0) and (1-x, 0) are generated when subdividing the v = 0 edge, vertices must be generated at (0, x) and (0, 1-x) when subdividing an otherwise identical u = 0 edge.
Rule 5 When processing two patches that are identical in all respects enumerated in rule 1 except for vertex order, the set of triangles generated for triangle and quad tessellation must be identical except for vertex and triangle order. For each triangle n1 produced by processing the first patch, there must be a triangle n2 produced when processing the second patch each of whose vertices has the same tessellation coordinates as one of the vertices in n1.
Rule 6 When processing two patches that are identical in all respects enumerated in rule 1 other than matching outer tessellation levels and/or vertex order, the set of interior triangles generated for triangle and quad tessellation must be identical in all respects except for vertex and triangle order. For each interior triangle n1 produced by processing the first patch, there must be a triangle n2 produced when processing the second patch each of whose vertices has the same tessellation coordinates as one of the vertices in n1. A triangle produced by the tessellator is considered an interior triangle if none of its vertices lie on an outer edge of the subdivided primitive.
Rule 7 For quad and triangle tessellation, the set of triangles connecting an inner and outer edge depends only on the inner and outer tessellation levels corresponding to that edge and the spacing decorations.
Rule 8 The value of all defined components of TessCoord will be in
the range [0, 1].
Additionally, for any defined component x of TessCoord, the results
of computing 1.0-x in a tessellation evaluation shader will be exact.
If any floating-point values in the range [0, 1] fail to satisfy this
property, such values must not be used as tessellation coordinate
components.
Glossary
The terms defined in this section are used consistently throughout this Specification and may be used with or without capitalization.
- Accessible (Descriptor Binding)
-
A descriptor binding is accessible to a shader stage if that stage is included in the
stageFlagsof the descriptor binding. Descriptors using that binding can only be used by stages in which they are accessible. - Acquire Operation (Resource)
-
An operation that acquires ownership of an image subresource or buffer range.
- Adjacent Vertex
-
A vertex in an adjacency primitive topology that is not part of a given primitive, but is accessible in geometry shaders.
- Advanced Blend Operation
-
Blending performed using one of the blend operation enums introduced by the
VK_EXT_blend_operation_advancedextension. See Advanced Blending Operations. - Aliased Range (Memory)
-
A range of a device memory allocation that is bound to multiple resources simultaneously.
- Allocation Scope
-
An association of a host memory allocation to a parent object or command, where the allocation’s lifetime ends before or at the same time as the parent object is freed or destroyed, or during the parent command.
- API Order
-
A set of ordering rules that govern how primitives in draw commands affect the framebuffer.
- Aspect (Image)
-
An image may contain multiple kinds, or aspects, of data for each pixel, where each aspect is used in a particular way by the pipeline and may be stored differently or separately from other aspects. For example, the color components of an image format make up the color aspect of the image, and may be used as a framebuffer color attachment. Some operations, like depth testing, operate only on specific aspects of an image. Others operations, like image/buffer copies, only operate on one aspect at a time.
- Attachment (Render Pass)
-
A zero-based integer index name used in render pass creation to refer to a framebuffer attachment that is accessed by one or more subpasses. The index also refers to an attachment description which includes information about the properties of the image view that will later be attached.
- Availability Operation
-
An operation that causes the values generated by specified memory write accesses to become available for future access.
- Available
-
A state of values written to memory that allows them to be made visible.
- Back-Facing
-
See Facingness.
- Batch
-
A single structure submitted to a queue as part of a queue submission command, describing a set of queue operations to execute.
- Backwards Compatibility
-
A given version of the API is backwards compatible with an earlier version if an application, relying only on valid behavior and functionality defined by the earlier specification, is able to correctly run against each version without any modification. This assumes no active attempt by that application to not run when it detects a different version.
- Full Compatibility
-
A given version of the API is fully compatible with another version if an application, relying only on valid behavior and functionality defined by either of those specifications, is able to correctly run against each version without any modification. This assumes no active attempt by that application to not run when it detects a different version.
- Binding (Memory)
-
An association established between a range of a resource object and a range of a memory object. These associations determine the memory locations affected by operations performed on elements of a resource object. Memory bindings are established using the vkBindBufferMemory command for non-sparse buffer objects, using the vkBindImageMemory command for non-sparse image objects, and using the vkQueueBindSparse command for sparse resources.
- Blend Constant
-
Four floating point (RGBA) values used as an input to blending.
- Blending
-
Arithmetic operations between a fragment color value and a value in a color attachment that produce a final color value to be written to the attachment.
- Buffer
-
A resource that represents a linear array of data in device memory. Represented by a VkBuffer object.
- Buffer View
-
An object that represents a range of a specific buffer, and state that controls how the contents are interpreted. Represented by a VkBufferView object.
- Built-In Variable
-
A variable decorated in a shader, where the decoration makes the variable take values provided by the execution environment or values that are generated by fixed-function pipeline stages.
- Built-In Interface Block
-
A block defined in a shader that contains only variables decorated with built-in decorations, and is used to match against other shader stages.
- Clip Coordinates
-
The homogeneous coordinate space that vertex positions (
Positiondecoration) are written in by vertex processing stages. - Clip Distance
-
A built-in output from vertex processing stages that defines a clip half-space against which the primitive is clipped.
- Clip Volume
-
The intersection of the view volume with all clip half-spaces.
- Color Attachment
-
A subpass attachment point, or image view, that is the target of fragment color outputs and blending.
- Color Fragment
-
A unique color value within a pixel of a multisampled color image. The fragment mask will contain indices to the color fragment.
- Color Renderable Format
-
A VkFormat where
VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BITis set in theoptimalTilingFeaturesorlinearTilingFeaturesfield of VkFormatProperties::optimalTilingFeatures returned by vkGetPhysicalDeviceFormatProperties, depending on the tiling used. - Color Sample Mask
-
A bitfield associated with a fragment, with one bit for each sample in the color attachment(s). Samples are considered to be covered based on the result of the Coverage Reduction stage. Uncovered samples do not write to color attachments.
- Combined Image Sampler
-
A descriptor type that includes both a sampled image and a sampler.
- Command Buffer
-
An object that records commands to be submitted to a queue. Represented by a VkCommandBuffer object.
- Command Pool
-
An object that command buffer memory is allocated from, and that owns that memory. Command pools aid multithreaded performance by enabling different threads to use different allocators, without internal synchronization on each use. Represented by a VkCommandPool object.
- Compatible Allocator
-
When allocators are compatible, allocations from each allocator can be freed by the other allocator.
- Compatible Image Formats
-
When formats are compatible, images created with one of the formats can have image views created from it using any of the compatible formats. Also see Size-Compatible Image Formats.
- Compatible Queues
-
Queues within a queue family. Compatible queues have identical properties.
- Component (Format)
-
A distinct part of a format. Depth, stencil, and color channels (e.g. R, G, B, A), are all separate components.
- Compressed Texel Block
-
An element of an image having a block-compressed format, comprising a rectangular block of texel values that are encoded as a single value in memory. Compressed texel blocks of a particular block-compressed format have a corresponding width, height, and depth that define the dimensions of these elements in units of texels, and a size in bytes of the encoding in memory.
- Coverage
-
A bitfield associated with a fragment, where each bit is associated to a rasterization sample. Samples are initially considered to be covered based on the result of rasterization, and then coverage can subsequently be turned on or off by other fragment operations or the fragment shader. Uncovered samples do not write to framebuffer attachments.
- Cull Distance
-
A built-in output from vertex processing stages that defines a cull half-space where the primitive is rejected if all vertices have a negative value for the same cull distance.
- Cull Volume
-
The intersection of the view volume with all cull half-spaces.
- Decoration (SPIR-V)
-
Auxiliary information such as built-in variables, stream numbers, invariance, interpolation type, relaxed precision, etc., added to variables or structure-type members through decorations.
- Depth/Stencil Attachment
-
A subpass attachment point, or image view, that is the target of depth and/or stencil test operations and writes.
- Depth/Stencil Format
-
A VkFormat that includes depth and/or stencil components.
- Depth/Stencil Image (or ImageView)
-
A VkImage (or VkImageView) with a depth/stencil format.
- Derivative Group
-
A set of fragment shader invocations that cooperate to compute derivatives, including implicit derivatives for sampled image operations.
- Descriptor
-
Information about a resource or resource view written into a descriptor set that is used to access the resource or view from a shader.
- Descriptor Binding
-
An entry in a descriptor set layout corresponding to zero or more descriptors of a single descriptor type in a set. Defined by a VkDescriptorSetLayoutBinding structure.
- Descriptor Pool
-
An object that descriptor sets are allocated from, and that owns the storage of those descriptor sets. Descriptor pools aid multithreaded performance by enabling different threads to use different allocators, without internal synchronization on each use. Represented by a VkDescriptorPool object.
- Descriptor Set
-
An object that resource descriptors are written into via the API, and that can be bound to a command buffer such that the descriptors contained within it can be accessed from shaders. Represented by a VkDescriptorSet object.
- Descriptor Set Layout
-
An object that defines the set of resources (types and counts) and their relative arrangement (in the binding namespace) within a descriptor set. Used when allocating descriptor sets and when creating pipeline layouts. Represented by a VkDescriptorSetLayout object.
- Device
-
The processor(s) and execution environment that perform tasks requested by the application via the Vulkan API.
- Device Group
-
A set of physical devices that support accessing each other’s memory and recording a single command buffer that can be executed on all the physical devices.
- Device Index
-
A zero-based integer that identifies one physical device from a logical device. A device index is valid if it is less than the number of physical devices in the logical device.
- Device Mask
-
A bitmask where each bit represents one device index. A device mask value is valid if every bit that is set in the mask is at a bit position that is less than the number of physical devices in the logical device.
- Device Memory
-
Memory accessible to the device. Represented by a VkDeviceMemory object.
- Device-Level Command
-
Any command that is dispatched from a logical device, or from a child object of a logical device.
- Device-Level Functionality
-
All device-level commands and objects, and their structures, enumerated types, and enumerants.
- Device-Level Object
-
Logical device objects and their child objects. For example, VkDevice, VkQueue, and VkCommandBuffer objects are device-level objects.
- Device-Local Memory
-
Memory that is connected to the device, and may be more performant for device access than host-local memory.
- Direct Drawing Commands
-
Drawing commands that take all their parameters as direct arguments to the command (and not sourced via structures in buffer memory as the indirect drawing commands). Includes vkCmdDraw, and vkCmdDrawIndexed.
- Disjoint
-
Disjoint planes are image planes to which memory is bound independently.
A disjoint image consists of multiple disjoint planes, and is created with theVK_IMAGE_CREATE_DISJOINT_BITbit set. - Dispatchable Handle
-
A handle of a pointer handle type which may be used by layers as part of intercepting API commands. The first argument to each Vulkan command is a dispatchable handle type.
- Dispatching Commands
-
Commands that provoke work using a compute pipeline. Includes vkCmdDispatch and vkCmdDispatchIndirect.
- Drawing Commands
-
Commands that provoke work using a graphics pipeline. Includes vkCmdDraw, vkCmdDrawIndexed, vkCmdDrawIndirect, vkCmdDrawIndirectCountKHR, vkCmdDrawIndexedIndirectCountKHR, vkCmdDrawIndirectCountAMD, vkCmdDrawIndexedIndirectCountAMD, and vkCmdDrawIndexedIndirect.
- Duration (Command)
-
The duration of a Vulkan command refers to the interval between calling the command and its return to the caller.
- Dynamic Storage Buffer
-
A storage buffer whose offset is specified each time the storage buffer is bound to a command buffer via a descriptor set.
- Dynamic Uniform Buffer
-
A uniform buffer whose offset is specified each time the uniform buffer is bound to a command buffer via a descriptor set.
- Dynamically Uniform
-
See Dynamically Uniform in section 2.2 “Terms” of the Khronos SPIR-V Specification.
- Element Size
-
The size (in bytes) used to store one element of an uncompressed format or the size (in bytes) used to store one block of a block-compressed format.
- Explicitly-Enabled Layer
-
A layer enabled by the application by adding it to the enabled layer list in vkCreateInstance or vkCreateDevice.
- Event
-
A synchronization primitive that is signaled when execution of previous commands complete through a specified set of pipeline stages. Events can be waited on by the device and polled by the host. Represented by a VkEvent object.
- Executable State (Command Buffer)
-
A command buffer that has ended recording commands and can be executed. See also Initial State and Recording State.
- Execution Dependency
-
A dependency that guarantees that certain pipeline stages’ work for a first set of commands has completed execution before certain pipeline stages’ work for a second set of commands begins execution. This is accomplished via pipeline barriers, subpass dependencies, events, or implicit ordering operations.
- Execution Dependency Chain
-
A sequence of execution dependencies that transitively act as a single execution dependency.
- Explicit chroma reconstruction
-
An implementation of sampler Y’CBCR conversion which reconstructs reduced-resolution chroma samples to luma resolution and then separately performs texture sample interpolation. This is distinct from an implicit implementation, which incorporates chroma sample reconstruction into texture sample interpolation.
- Extension Scope
-
The set of objects and commands that can be affected by an extension. Extensions are either device scope or instance scope.
- External Handle
-
A resource handle which has meaning outside of a specific Vulkan device or its parent instance. External handles may be used to share resources between multiple Vulkan devices in different instances, or between Vulkan and other APIs. Some external handle types correspond to platform-defined handles, in which case the resource may outlive any particular Vulkan device or instance and may be transferred between processes, or otherwise manipulated via functionality defined by the platform for that handle type.
- External synchronization
-
A type of synchronization required of the application, where parameters defined to be externally synchronized must not be used simultaneously in multiple threads.
- Facingness (Polygon)
-
A classification of a polygon as either front-facing or back-facing, depending on the orientation (winding order) of its vertices.
- Facingness (Fragment)
-
A fragment is either front-facing or back-facing, depending on the primitive it was generated from. If the primitive was a polygon (regardless of polygon mode), the fragment inherits the facingness of the polygon. All other fragments are front-facing.
- Fence
-
A synchronization primitive that is signaled when a set of batches or sparse binding operations complete execution on a queue. Fences can be waited on by the host. Represented by a VkFence object.
- Flat Shading
-
A property of a vertex attribute that causes the value from a single vertex (the provoking vertex) to be used for all vertices in a primitive, and for interpolation of that attribute to return that single value unaltered.
- Fragment Input Attachment Interface
-
Variables with
UniformConstantstorage class and a decoration ofInputAttachmentIndexthat are statically used by a fragment shader’s entry point, which receive values from input attachments. - Fragment Mask
-
A lookup table that associates color samples with color fragment values.
- Fragment Output Interface
-
A fragment shader entry point’s variables with
Outputstorage class, which output to color and/or depth/stencil attachments. - Framebuffer
-
A collection of image views and a set of dimensions that, in conjunction with a render pass, define the inputs and outputs used by drawing commands. Represented by a VkFramebuffer object.
- Framebuffer Attachment
-
One of the image views used in a framebuffer.
- Framebuffer Coordinates
-
A coordinate system in which adjacent pixels’ coordinates differ by 1 in x and/or y, with (0,0) in the upper left corner and pixel centers at half-integers.
- Framebuffer-Space
-
Operating with respect to framebuffer coordinates.
- Framebuffer-Local
-
A framebuffer-local dependency guarantees that only for a single framebuffer region, the first set of operations happens-before the second set of operations.
- Framebuffer-Global
-
A framebuffer-global dependency guarantees that for all framebuffer regions, the first set of operations happens-before the second set of operations.
- Framebuffer Region
-
A framebuffer region is a set of sample (x, y, layer, sample) coordinates that is a subset of the entire framebuffer.
- Front-Facing
-
See Facingness.
- Global Workgroup
-
A collection of local workgroups dispatched by a single dispatch command.
- Handle
-
An opaque integer or pointer value used to refer to a Vulkan object. Each object type has a unique handle type.
- Happen-after
-
A transitive, irreflexive and antisymmetric ordering relation between operations. An execution dependency with a source of A and a destination of B enforces that B happens-after A. The inverse relation of happens-before.
- Happen-before
-
A transitive, irreflexive and antisymmetric ordering relation between operations. An execution dependency with a source of A and a destination of B enforces that A happens-before B. The inverse relation of happens-after.
- Helper Invocation
-
A fragment shader invocation that is created solely for the purposes of evaluating derivatives for use in non-helper fragment shader invocations, and which does not have side effects.
- Host
-
The processor(s) and execution environment that the application runs on, and that the Vulkan API is exposed on.
- Host Mapped Foreign Memory
-
Memory owned by a foreign device that is mapped for host access.
- Host Memory
-
Memory not accessible to the device, used to store implementation data structures.
- Host-Accessible Subresource
-
A buffer, or a linear image subresource in either the
VK_IMAGE_LAYOUT_PREINITIALIZEDorVK_IMAGE_LAYOUT_GENERALlayout. Host-accessible subresources have a well-defined addressing scheme which can be used by the host. - Host-Local Memory
-
Memory that is not local to the device, and may be less performant for device access than device-local memory.
- Host-Visible Memory
-
Device memory that can be mapped on the host and can be read and written by the host.
- Identically Defined Objects
-
Objects of the same type where all arguments to their creation or allocation functions, with the exception of
pAllocator, are-
Vulkan handles which refer to the same object or
-
identical scalar or enumeration values or
-
Host pointers which point to an array of values or structures which also satisfy these three constraints.
-
- Image
-
A resource that represents a multi-dimensional formatted interpretation of device memory. Represented by a VkImage object.
- Image Subresource
-
A specific mipmap level and layer of an image.
- Image Subresource Range
-
A set of image subresources that are contiguous mipmap levels and layers.
- Image View
-
An object that represents an image subresource range of a specific image, and state that controls how the contents are interpreted. Represented by a VkImageView object.
- Immutable Sampler
-
A sampler descriptor provided at descriptor set layout creation time, and that is used for that binding in all descriptor sets allocated from the layout, and cannot be changed.
- Implicit chroma reconstruction
-
An implementation of sampler Y’CBCR conversion which reconstructs the reduced-resolution chroma samples directly at the sample point, as part of the normal texture sampling operation. This is distinct from an explicit chroma reconstruction implementation, which reconstructs the reduced-resolution chroma samples to the resolution of the luma samples, then filters the result as part of texture sample interpolation.
- Implicitly-Enabled Layer
-
A layer enabled by a loader-defined mechanism outside the Vulkan API, rather than explicitly by the application during instance or device creation.
- Index Buffer
-
A buffer bound via vkCmdBindIndexBuffer which is the source of index values used to fetch vertex attributes for a vkCmdDrawIndexed or vkCmdDrawIndexedIndirect command.
- Indexed Drawing Commands
-
Drawing commands which use an index buffer as the source of index values used to fetch vertex attributes for a drawing command. Includes vkCmdDrawIndexed, vkCmdDrawIndexedIndirectCountKHR, vkCmdDrawIndexedIndirectCountAMD, and vkCmdDrawIndexedIndirect.
- Indirect Commands
-
Drawing or dispatching commands that source some of their parameters from structures in buffer memory. Includes vkCmdDrawIndirect, vkCmdDrawIndexedIndirect, vkCmdDrawIndirectCountKHR, vkCmdDrawIndexedIndirectCountKHR, vkCmdDrawIndirectCountAMD, vkCmdDrawIndexedIndirectCountAMD, and vkCmdDispatchIndirect.
- Indirect Commands Layout
-
A definition of a sequence of commands, that are generated on the device via vkCmdProcessCommandsNVX. Each sequence is comprised of multiple VkIndirectCommandsTokenTypeNVX, which represent a subset of traditional command buffer commands. Represented as VkIndirectCommandsLayoutNVX.
- Indirect Drawing Commands
-
Drawing commands that source some of their parameters from structures in buffer memory. Includes vkCmdDrawIndirect, vkCmdDrawIndirectCountKHR, vkCmdDrawIndexedIndirectCountKHR, vkCmdDrawIndirectCountAMD, vkCmdDrawIndexedIndirectCountAMD, and vkCmdDrawIndexedIndirect.
- Initial State (Command Buffer)
-
A command buffer that has not begun recording commands. See also Recorded State and Executable State.
- Input Attachment
-
A descriptor type that represents an image view, and supports unfiltered read-only access in a shader, only at the fragment’s location in the view.
- Instance
-
The top-level Vulkan object, which represents the application’s connection to the implementation. Represented by a VkInstance object.
- Instance-Level Command
-
Any command that is dispatched from an instance, or from a child object of an instance, except for physical devices and their children.
- Instance-Level Functionality
-
All instance-level commands and objects, and their structures, enumerated types, and enumerants.
- Instance-Level Object
-
High-level Vulkan objects, which are not physical devices, nor children of physical devices. For example, VkInstance is an instance-level object.
- Instance (Memory)
-
In a logical device representing more than one physical device, some device memory allocations have the requested amount of memory allocated multiple times, once for each physical device in a device mask. Each such replicated allocation is an instance of the device memory.
- Instance (Resource)
-
In a logical device representing more than one physical device, buffer and image resources exist on all physical devices but can be bound to memory differently on each. Each such replicated resource is an instance of the resource.
- Internal Synchronization
-
A type of synchronization required of the implementation, where parameters not defined to be externally synchronized may require internal mutexing to avoid multithreaded race conditions.
- Invocation (Shader)
-
A single execution of an entry point in a SPIR-V module. For example, a single vertex’s execution of a vertex shader or a single fragment’s execution of a fragment shader.
- Invocation Group
-
A set of shader invocations that are executed in parallel and that must execute the same control flow path in order for control flow to be considered dynamically uniform.
- Linear Resource
-
A resource is linear if it is a VkBuffer, or a VkImage created with
VK_IMAGE_TILING_LINEAR. A resource is non-linear if it is a VkImage created withVK_IMAGE_TILING_OPTIMAL. - Local Workgroup
-
A collection of compute shader invocations invoked by a single dispatch command, which share data via
WorkgroupLocalvariables and can synchronize with each other. - Logical Device
-
An object that represents the application’s interface to the physical device. The logical device is the parent of most Vulkan objects. Represented by a VkDevice object.
- Logical Operation
-
Bitwise operations between a fragment color value and a value in a color attachment, that produce a final color value to be written to the attachment.
- Lost Device
-
A state that a logical device may be in as a result of unrecoverable implementation errors, or other exceptional conditions.
- Mappable
-
See Host-Visible Memory.
- Memory Dependency
-
A memory dependency is an execution dependency which includes availability and visibility operations such that:
-
The first set of operations happens-before the availability operation
-
The availability operation happens-before the visibility operation
-
The visibility operation happens-before the second set of operations
-
- Memory Heap
-
A region of memory from which device memory allocations can be made.
- Memory Type
-
An index used to select a set of memory properties (e.g. mappable, cached) for a device memory allocation.
- Mip Tail Region
-
The set of mipmap levels of a sparse residency texture that are too small to fill a sparse block, and that must all be bound to memory collectively and opaquely.
- Multi-planar
-
A multi-planar format (or “planar format”) is an image format consisting of more than one plane, identifiable with a
_2PLANEor_3PLANEcomponent to the format name and listed in Formats requiring sampler Y’CBCR conversion forVK_IMAGE_ASPECT_COLOR_BITimage views. A multi-planar image (or “planar image”) is an image of a multi-planar format. - Non-Dispatchable Handle
-
A handle of an integer handle type. Handle values may not be unique, even for two objects of the same type.
- Non-Indexed Drawing Commands
-
Drawing commands for which the vertex attributes are sourced in linear order from the vertex input attributes for a drawing command (i.e. they do not use an index buffer). Includes vkCmdDraw, vkCmdDrawIndirectCountKHR, vkCmdDrawIndirectCountAMD, and vkCmdDrawIndirect.
- Normalized
-
A value that is interpreted as being in the range [0,1] as a result of being implicitly divided by some other value.
- Normalized Device Coordinates
-
A coordinate space after perspective division is applied to clip coordinates, and before the viewport transformation converts to framebuffer coordinates.
- Object Table
-
A binding table for various resources (VkPipeline, VkBuffer, VkDescriptorSet), so that they can be referenced in device-generated command processing. Represented as VkObjectTableNVX. Entries are registered or unregistered via
uint32_tindices. - Overlapped Range (Aliased Range)
-
The aliased range of a device memory allocation that intersects a given image subresource of an image or range of a buffer.
- Ownership (Resource)
-
If an entity (e.g. a queue family) has ownership of a resource, access to that resource is well-defined for access by that entity.
- Packed Format
-
A format whose components are stored as a single data element in memory, with their relative locations defined within that element.
- Passthrough Geometry Shader
-
A geometry shader which uses the
PassthroughNVdecoration on a variable in its input interface. Output primitives in a passthrough geometry shader always have the same topology as the input primitive and are not produced by emitting vertices. - Payload
-
Importable or exportable reference to the internal data of an object in Vulkan.
- Peer Memory
-
An instance of memory corresponding to a different physical device than the physical device performing the memory access, in a logical device that represents multiple physical devices.
- Physical Device
-
An object that represents a single device in the system. Represented by a VkPhysicalDevice object.
- Physical-Device-Level Command
-
Any command that is dispatched from a physical device.
- Physical-Device-Level Functionality
-
All physical-device-level commands and objects, and their structures, enumerated types, and enumerants.
- Physical-Device-Level Object
-
Physical device objects. For example, VkPhysicalDevice is a physical-device-level object.
- Pipeline
-
An object that controls how graphics or compute work is executed on the device. A pipeline includes one or more shaders, as well as state controlling any non-programmable stages of the pipeline. Represented by a VkPipeline object.
- Pipeline Barrier
-
An execution and/or memory dependency recorded as an explicit command in a command buffer, that forms a dependency between the previous and subsequent commands.
- Pipeline Cache
-
An object that can be used to collect and retrieve information from pipelines as they are created, and can be populated with previously retrieved information in order to accelerate pipeline creation. Represented by a VkPipelineCache object.
- Pipeline Layout
-
An object that defines the set of resources (via a collection of descriptor set layouts) and push constants used by pipelines that are created using the layout. Used when creating a pipeline and when binding descriptor sets and setting push constant values. Represented by a VkPipelineLayout object.
- Pipeline Stage
-
A logically independent execution unit that performs some of the operations defined by an action command.
pNextChain-
A set of structures chained together through their
pNextmembers. - Planar
-
See multi-planar.
- Plane
-
An image plane is part of the representation of an image, containing a subset of the color channels required to represent the texels in the image and with a contiguous mapping of coordinates to bound memory. Most images consist only of a single plane, but some formats spread the channels across multiple image planes. The host-accessible properties of each image plane are accessed in a linear layout using vkGetImageSubresourceLayout. If a multi-planar image is created with the
VK_IMAGE_CREATE_DISJOINT_BITbit set, the image is described as disjoint, and its planes are therefore are bound to memory independently. - Point Sampling (Rasterization)
-
A rule that determines whether a fragment sample location is covered by a polygon primitive by testing whether the sample location is in the interior of the polygon in framebuffer-space, or on the boundary of the polygon according to the tie-breaking rules.
- Presentable image
-
A
VkImageobject obtained from aVkSwapchainKHRused to present to aVkSurfaceKHRobject. - Preserve Attachment
-
One of a list of attachments in a subpass description that is not read or written by the subpass, but that is read or written on earlier and later subpasses and whose contents must be preserved through this subpass.
- Primary Command Buffer
-
A command buffer that can execute secondary command buffers, and can be submitted directly to a queue.
- Primitive Topology
-
State that controls how vertices are assembled into primitives, e.g. as lists of triangles, strips of lines, etc..
- Promoted
-
An extension whose interfaces are later made available as part of a core version of the API, with the author ID suffixes removed, is said to be promoted to that core version. Minor differences, such as making the availability of specific features from the extension supported only if a corresponding feature bit is enabled, may still exist.
- Protected Buffer
-
A buffer to which protected device memory can be bound.
- Protected-capable Device Queue
-
A device queue to which protected command buffers can be submitted.
- Protected Command Buffer
-
A command buffer which can be submitted to a protected-capable device queue.
- Protected Device Memory
-
Device memory which can be visible to the device but must not be visible to the host.
- Protected Image
-
An image to which protected device memory can be bound.
- Provoking Vertex
-
The vertex in a primitive from which flat shaded attribute values are taken. This is generally the “first” vertex in the primitive, and depends on the primitive topology.
- Push Constants
-
A small bank of values writable via the API and accessible in shaders. Push constants allow the application to set values used in shaders without creating buffers or modifying and binding descriptor sets for each update.
- Push Constant Interface
-
The set of variables with
PushConstantstorage class that are statically used by a shader entry point, and which receive values from push constant commands. - Push Descriptors
-
Descriptors that are written directly into a command buffer rather than into a descriptor set. Push descriptors allow the application to set descriptors used in shaders without allocating or modifying descriptor sets for each update.
- Descriptor Update Template
-
An object that specifies a mapping from descriptor update information in host memory to elements in a descriptor set, which helps enable more efficient descriptor set updates.
- Query Pool
-
An object that contains a number of query entries and their associated state and results. Represented by a VkQueryPool object.
- Queue
-
An object that executes command buffers and sparse binding operations on a device. Represented by a VkQueue object.
- Queue Family
-
A set of queues that have common properties and support the same functionality, as advertised in VkQueueFamilyProperties.
- Queue Operation
-
A unit of work to be executed by a specific queue on a device, submitted via a queue submission command. Each queue submission command details the specific queue operations that occur as a result of calling that command. Queue operations typically include work that is specific to each command, and synchronization tasks.
- Queue Submission
-
Zero or more batches and an optional fence to be signaled, passed to a command for execution on a queue. See the Devices and Queues chapter for more information.
- Recording State (Command Buffer)
-
A command buffer that is ready to record commands. See also Initial State and Executable State.
- Release Operation (Resource)
-
An operation that releases ownership of an image subresource or buffer range.
- Render Pass
-
An object that represents a set of framebuffer attachments and phases of rendering using those attachments. Represented by a VkRenderPass object.
- Render Pass Instance
-
A use of a render pass in a command buffer.
- Required Extensions
-
Extensions that must be enabled alongside extensions dependent on them (see Extension Dependencies).
- Reset (Command Buffer)
-
Resetting a command buffer discards any previously recorded commands and puts a command buffer in the initial state.
- Residency Code
-
An integer value returned by sparse image instructions, indicating whether any sparse unbound texels were accessed.
- Resolve Attachment
-
A subpass attachment point, or image view, that is the target of a multisample resolve operation from the corresponding color attachment at the end of the subpass.
- Retired Swapchain
-
A swapchain that has been used as the
oldSwapchainparameter to vkCreateSwapchainKHR. Images cannot be acquired from a retired swapchain, however images that were acquired (but not presented) before the swapchain was retired can be presented. - Sampled Image
-
A descriptor type that represents an image view, and supports filtered (sampled) and unfiltered read-only access in a shader.
- Sampler
-
An object that contains state that controls how sampled image data is sampled (or filtered) when accessed in a shader. Also a descriptor type describing the object. Represented by a VkSampler object.
- Secondary Command Buffer
-
A command buffer that can be executed by a primary command buffer, and must not be submitted directly to a queue.
- Self-Dependency
-
A subpass dependency from a subpass to itself, i.e. with
srcSubpassequal todstSubpass. A self-dependency is not automatically performed during a render pass instance, rather a subset of it can be performed via vkCmdPipelineBarrier during the subpass. - Semaphore
-
A synchronization primitive that supports signal and wait operations, and can be used to synchronize operations within a queue or across queues. Represented by a VkSemaphore object.
- Shader
-
Instructions selected (via an entry point) from a shader module, which are executed in a shader stage.
- Shader Code
-
A stream of instructions used to describe the operation of a shader.
- Shader Module
-
A collection of shader code, potentially including several functions and entry points, that is used to create shaders in pipelines. Represented by a VkShaderModule object.
- Shader Stage
-
A stage of the graphics or compute pipeline that executes shader code.
- Shared presentable image
-
A presentable image created from a swapchain with VkPresentModeKHR set to either
VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHRorVK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR. - Side Effect
-
A store to memory or atomic operation on memory from a shader invocation.
- Single-plane format
-
A format that is not multi-planar.
- Size-Compatible Image Formats
-
When a compressed image format and an uncompressed image format are size-compatible, it means that the element size of the uncompressed format must equal the element size (compressed texel block size) of the compressed format.
- Sparse Block
-
An element of a sparse resource that can be independently bound to memory. Sparse blocks of a particular sparse resource have a corresponding size in bytes that they use in the bound memory.
- Sparse Image Block
-
A sparse block in a sparse partially-resident image. In addition to the sparse block size in bytes, sparse image blocks have a corresponding width, height, and depth that define the dimensions of these elements in units of texels or compressed texel blocks, the latter being used in case of sparse images having a block-compressed format.
- Sparse Unbound Texel
-
A texel read from a region of a sparse texture that does not have memory bound to it.
- Static Use
-
An object in a shader is statically used by a shader entry point if any function in the entry point’s call tree contains an instruction using the object. Static use is used to constrain the set of descriptors used by a shader entry point.
- Storage Buffer
-
A descriptor type that represents a buffer, and supports reads, writes, and atomics in a shader.
- Storage Image
-
A descriptor type that represents an image view, and supports unfiltered loads, stores, and atomics in a shader.
- Storage Texel Buffer
-
A descriptor type that represents a buffer view, and supports unfiltered, formatted reads, writes, and atomics in a shader.
- Subgroup
-
A set of shader invocations that can synchronize and share data with each other efficiently. In compute shaders, the local workgroup is a superset of the subgroup.
- Subgroup Mask
-
A bitmask for all invocations in the current subgroup with one bit per invocation, starting with the least significant bit in the first vector component, continuing to the last bit (less than
SubgroupSize) in the last required vector component. - Subpass
-
A phase of rendering within a render pass, that reads and writes a subset of the attachments.
- Subpass Dependency
-
An execution and/or memory dependency between two subpasses described as part of render pass creation, and automatically performed between subpasses in a render pass instance. A subpass dependency limits the overlap of execution of the pair of subpasses, and can provide guarantees of memory coherence between accesses in the subpasses.
- Subpass Description
-
Lists of attachment indices for input attachments, color attachments, depth/stencil attachment, resolve attachments, and preserve attachments used by the subpass in a render pass.
- Subset (Self-Dependency)
-
A subset of a self-dependency is a pipeline barrier performed during the subpass of the self-dependency, and whose stage masks and access masks each contain a subset of the bits set in the identically named mask in the self-dependency.
- Texel Coordinate System
-
One of three coordinate systems (normalized, unnormalized, integer) that define how texel coordinates are interpreted in an image or a specific mipmap level of an image.
- Uniform Texel Buffer
-
A descriptor type that represents a buffer view, and supports unfiltered, formatted, read-only access in a shader.
- Uniform Buffer
-
A descriptor type that represents a buffer, and supports read-only access in a shader.
- Unnormalized
-
A value that is interpreted according to its conventional interpretation, and is not normalized.
- Unprotected Buffer
-
A buffer to which unprotected device memory can be bound.
- Unprotected Command Buffer
-
A command buffer which can be submitted to an unprotected device queue or a protected-capable device queue.
- Unprotected Device Memory
-
Device memory which can be visible to the device and can be visible to the host.
- Unprotected Image
-
An image to which unprotected device memory can be bound.
- User-Defined Variable Interface
-
A shader entry point’s variables with
InputorOutputstorage class that are not built-in variables. - Vertex Input Attribute
-
A graphics pipeline resource that produces input values for the vertex shader by reading data from a vertex input binding and converting it to the attribute’s format.
- Validation Cache
-
An object that can be used to collect and retrieve validation results from the validation layers, and can be populated with previously retrieved results in order to accelerate the validation process. Represented by a VkValidationCacheEXT object.
- Vertex Input Binding
-
A graphics pipeline resource that is bound to a buffer and includes state that affects addressing calculations within that buffer.
- Vertex Input Interface
-
A vertex shader entry point’s variables with
Inputstorage class, which receive values from vertex input attributes. - Vertex Processing Stages
-
A set of shader stages that comprises the vertex shader, tessellation control shader, tessellation evaluation shader, and geometry shader stages.
- View Mask
-
When multiview is enabled, a view mask is a property of a subpass controlling which views the rendering commands are broadcast to.
- View Volume
-
A subspace in homogeneous coordinates, corresponding to post-projection x and y values between -1 and +1, and z values between 0 and +1.
- Viewport Transformation
-
A transformation from normalized device coordinates to framebuffer coordinates, based on a viewport rectangle and depth range.
- Visibility Operation
-
An operation that causes available values to become visible to specified memory accesses.
- Visible
-
A state of values written to memory that allows them to be accessed by a set of operations.
Common Abbreviations
Abbreviations and acronyms are sometimes used in the Specification and the API where they are considered clear and commonplace, and are defined here:
- Src
-
Source
- Dst
-
Destination
- Min
-
Minimum
- Max
-
Maximum
- Rect
-
Rectangle
- Info
-
Information
- LOD
-
Level of Detail
- ID
-
Identifier
- UUID
-
Universally Unique Identifier
- Op
-
Operation
- R
-
Red color component
- G
-
Green color component
- B
-
Blue color component
- A
-
Alpha color component
Prefixes
Prefixes are used in the API to denote specific semantic meaning of Vulkan names, or as a label to avoid name clashes, and are explained here:
- VK/Vk/vk
-
Vulkan namespace
All types, commands, enumerants and defines in this specification are prefixed with these two characters. - PFN/pfn
-
Function Pointer
Denotes that a type is a function pointer, or that a variable is of a pointer type. - p
-
Pointer
Variable is a pointer. - vkCmd
-
Commands that record commands in command buffers
These API commands do not result in immediate processing on the device. Instead, they record the requested action in a command buffer for execution when the command buffer is submitted to a queue. - s
-
Structure
Used to denote theVK_STRUCTURE_TYPE*member of each structure insType
Appendix G: Credits (Informative)
Vulkan 1.1 is the result of contributions from many people and companies participating in the Khronos Vulkan Working Group, as well as input from the Vulkan Advisory Panel.
Members of the Working Group, including the company that they represented at the time of their most recent contribution, are listed in the following sections. Some specific contributions made by individuals are listed together with their name.
Working Group Contributors to Vulkan 1.1 and 1.0
-
Adam Jackson, Red Hat
-
Alexander Galazin, Arm
-
Alex Bourd, Qualcomm Technologies, Inc.
-
Alon Or-bach, Samsung Electronics (WSI technical sub-group chair)
-
Andrew Garrard, Samsung Electronics (format wrangler)
-
Andrew Woloszyn, Google
-
Antoine Labour, Google
-
Bill Licea-Kane, Qualcomm Technologies, Inc.
-
Cass Everitt, Oculus VR
-
Chad Versace, Google
-
Christophe Riccio, Unity Technologies
-
Dan Baker, Oxide Games
-
Dan Ginsburg, Valve Software
-
Daniel Johnston, Intel
-
Daniel Koch, NVIDIA (Shader Interfaces; Features, Limits, and Formats)
-
Daniel Rakos, AMD
-
David Airlie, Red Hat
-
David Miller, Miller & Mattson (Vulkan reference card)
-
David Neto, Google
-
Dominik Witczak, AMD
-
Graeme Leese, Broadcom
-
Graham Sellers, AMD
-
Ian Romanick, Intel
-
James Jones, NVIDIA
-
Jan-Harald Fredriksen, Arm
-
Jan Hermes, Continental Corporation
-
Jason Ekstrand, Intel
-
Jeff Bolz, NVIDIA (extensive contributions, exhaustive review and rewrites for technical correctness)
-
Jeff Juliano, NVIDIA
-
Jesse Barker, Unity Technologies
-
Jesse Hall, Google
-
Johannes van Waveren, Oculus VR
-
John Kessenich, Google (SPIR-V and GLSL for Vulkan spec author)
-
John McDonald, Valve Software
-
Jonas Gustavsson, Samsung Electronics
-
Jon Ashburn, LunarG
-
Jon Leech, Independent (XML toolchain, normative language, release wrangler)
-
Jungwoo Kim, Samsung Electronics
-
Kathleen Mattson, Miller & Mattson (Vulkan reference card)
-
Kenneth Benzie, Codeplay Software Ltd.
-
Kerch Holt, NVIDIA (SPIR-V technical sub-group chair)
-
Kristian Kristensen, Intel
-
Mark Lobodzinski, LunarG
-
Mathias Heyer, NVIDIA
-
Mathias Schott, NVIDIA
-
Maurice Ribble, Qualcomm Technologies, Inc.
-
Michael Worcester, Imagination Technologies
-
Mika Isojarvi, Google
-
Mitch Singer, AMD
-
Neil Henning, Codeplay Software Ltd.
-
Neil Trevett, NVIDIA
-
Norbert Nopper, Independent
-
Pierre Boudier, NVIDIA
-
Pierre-Loup Griffais, Valve Software
-
Piers Daniell, NVIDIA (dynamic state, copy commands, memory types)
-
Pyry Haulos, Google (Vulkan conformance test subcommittee chair)
-
Ray Smith, Arm
-
Robert Simpson, Qualcomm Technologies, Inc.
-
Rolando Caloca Olivares, Epic Games
-
Sean Harmer, KDAB Group
-
Shannon Woods, Google
-
Slawomir Cygan, Intel
-
Slawomir Grajewski, Intel
-
Stuart Smith, Imagination Technologies
-
Timothy Lottes, AMD
-
Tobias Hector, Imagination Technologies (validity language and toolchain)
-
Tom Olson, Arm (working group chair)
-
Tony Barbour, LunarG
-
Yanjun Zhang, VeriSilicon
Working Group Contributors to Vulkan 1.1
-
Aaron Greig, Codeplay Software Ltd.
-
Aaron Hagan, AMD
-
Alan Ward, Google
-
Alejandro Piñeiro, Igalia
-
Andres Gomez, Igalia
-
Baldur Karlsson, Independent
-
Barthold Lichtenbelt, NVIDIA
-
Bas Nieuwenhuizen, Google
-
Bill Hollings, Brenwill
-
Colin Riley, AMD
-
Cort Stratton, Google
-
Courtney Goeltzenleuchter, Google
-
Dae Kim, Imagination Technologies
-
Daniel Stone, Collabora
-
David Pinedo, LunarG
-
Dejan Mircevski, Google
-
Dzmitry Malyshau, Mozilla
-
Erika Johnson, LunarG
-
Greg Fischer, LunarG
-
Hans-Kristian Arntzen, Arm
-
Iago Toral, Igalia
-
Ian Elliott, Google
-
Jeff Leger, Qualcomm Technologies, Inc.
-
Jeff Vigil, Samsung Electronics
-
Jens Owen, Google
-
Joe Davis, Samsung Electronics
-
John Zulauf, LunarG
-
Jordan Justen, Intel
-
Jörg Wagner, Arm
-
Kalle Raita, Google
-
Karen Ghavam, LunarG
-
Karl Schultz, LunarG
-
Kenneth Russell, Google
-
Kevin O’Neil, AMD
-
Lauri Ilola, Nokia
-
Lenny Komow, LunarG
-
Lionel Landwerlin, Intel
-
Maciej Jesionowski, AMD
-
Mais Alnasser, AMD
-
Marcin Rogucki, Mobica
-
Mark Callow, Independent
-
Mark Kilgard, NVIDIA
-
Markus Tavenrath, NVIDIA
-
Mark Young, LunarG
-
Matthäus Chajdas, AMD
-
Matt Netsch, Qualcomm Technologies, Inc.
-
Michael O’Hara, AMD
-
Michael Wong, Codeplay Software Ltd.
-
Mike Schuchardt, LunarG
-
Mike Weiblen, LunarG
-
Nicolai Hähnle, AMD
-
Nuno Subtil, NVIDIA
-
Patrick Cozzi, Independent
-
Petros Bantolas, Imagination Technologies
-
Ralph Potter, Codeplay Software Ltd.
-
Rob Barris, NVIDIA
-
Ruihao Zhang, Qualcomm Technologies, Inc.
-
Sorel Bosan, AMD
-
Stephen Huang, Mediatek
-
Tilmann Scheller, Samsung Electronics
-
Tomasz Bednarz, Independent
-
Victor Eruhimov, ???
-
Wolfgang Engel, ???
Working Group Contributors to Vulkan 1.0
-
Adam Śmigielski, Mobica
-
Allen Hux, Intel
-
Andrew Cox, Samsung Electronics
-
Andrew Poole, Samsung Electronics
-
Andrew Rafter, Samsung Electronics
-
Andrew Richards, Codeplay Software Ltd.
-
Aras Pranckevičius, Unity Technologies
-
Ashwin Kolhe, NVIDIA
-
Ben Bowman, Imagination Technologies
-
Benj Lipchak
-
Bill Hollings, The Brenwill Workshop
-
Brent E. Insko, Intel
-
Brian Ellis, Qualcomm Technologies, Inc.
-
Cemil Azizoglu, Canonical
-
Chang-Hyo Yu, Samsung Electronics
-
Chia-I Wu, LunarG
-
Chris Frascati, Qualcomm Technologies, Inc.
-
Cody Northrop, LunarG
-
Courtney Goeltzenleuchter, LunarG
-
Damien Leone, NVIDIA
-
David Mao, AMD
-
David Yu, Pixar
-
Frank (LingJun) Chen, Qualcomm Technologies, Inc.
-
Fred Liao, Mediatek
-
Gabe Dagani, Freescale
-
Graham Connor, Imagination Technologies
-
Hwanyong Lee, Kyungpook National University
-
Ian Elliott, LunarG
-
James Hughes, Oculus VR
-
Jeff Vigil, Qualcomm Technologies, Inc.
-
Jens Owen, LunarG
-
Jeremy Hayes, LunarG
-
Jonathan Hamilton, Imagination Technologies
-
Krzysztof Iwanicki, Samsung Electronics
-
Larry Seiler, Intel
-
Lutz Latta, Lucasfilm
-
Maria Rovatsou, Codeplay Software Ltd.
-
Mark Callow
-
Mateusz Przybylski, Intel
-
Maxim Lukyanov, Samsung Electronics
-
Michael Lentine, Google
-
Michal Pietrasiuk, Intel
-
Mike Stroyan, LunarG
-
Minyoung Son, Samsung Electronics
-
Mythri Venugopal, Samsung Electronics
-
Naveen Leekha, Google
-
Nick Penwarden, Epic Games
-
Niklas Smedberg, Unity Technologies
-
Pat Brown, NVIDIA
-
Patrick Doane, Blizzard Entertainment
-
Peter Lohrmann, Valve Software
-
Piotr Bialecki, Intel
-
Prabindh Sundareson, Samsung Electronics
-
Rob Stepinski, Transgaming
-
Roy Ju, Mediatek
-
Rufus Hamede, Imagination Technologies
-
Sean Ellis, Arm
-
Stefanus Du Toit, Google
-
Steve Hill, Broadcom
-
Steve Viggers, Core Avionics & Industrial Inc.
-
Tim Foley, Intel
-
Timo Suoranta, AMD
-
Tobin Ehlis, LunarG
-
Tomasz Kubale, Intel
-
Wayne Lister, Imagination Technologies
Other Credits
In addition to the Working Group, the Vulkan Advisory Panel members provided important real-world usage information and advice that helped guide design decisions.
Administrative support to the Working Group for Vulkan 1.1 was provided by Khronos staff including Angela Cheng, Ann Thorsnes, Emily Stearns, Liz Maitral, and Dominic Agoro-Ombaka; and by Alex Crabb of Caster Communications.
Administrative support for Vulkan 1.0 was provided by Andrew Riegel, Elizabeth Riegel, Glenn Fredericks, Kathleen Mattson and Michelle Clark of Gold Standard Group.
Technical support was provided by James Riordon, webmaster of Khronos.org and OpenGL.org.