vkCmdSetDescriptorBufferOffsetsEXT(3)

# vkCmdSetDescriptorBufferOffsetsEXT(3) Manual Page

## Name

vkCmdSetDescriptorBufferOffsetsEXT - Setting descriptor buffer offsets in a command buffer

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## C Specification

To set descriptor buffer offsets in a command buffer, call:

    // Provided by VK_EXT_descriptor_buffer
    void vkCmdSetDescriptorBufferOffsetsEXT(
        VkCommandBuffer                             commandBuffer,
        VkPipelineBindPoint                         pipelineBindPoint,
        VkPipelineLayout                            layout,
        uint32_t                                    firstSet,
        uint32_t                                    setCount,
        const uint32_t*                             pBufferIndices,
        const VkDeviceSize*                         pOffsets);

## Parameters

- `commandBuffer` is the command buffer in which the descriptor buffer offsets will be set.

- `pipelineBindPoint` is a VkPipelineBindPoint indicating the type of the pipeline that will use the descriptors.

- `layout` is a VkPipelineLayout object used to program the bindings.

- `firstSet` is the number of the first set to be bound.

- `setCount` is the number of elements in the `pBufferIndices` and `pOffsets` arrays.

- `pBufferIndices` is a pointer to an array of indices into the descriptor buffer binding points set by vkCmdBindDescriptorBuffersEXT.

- `pOffsets` is a pointer to an array of `VkDeviceSize` offsets to apply to the bound descriptor buffers.

## Description

`vkCmdSetDescriptorBufferOffsetsEXT` binds `setCount` pairs of descriptor buffers, specified by indices into the binding points bound using vkCmdBindDescriptorBuffersEXT, and buffer offsets to set numbers [`firstSet`..`firstSet`+`descriptorSetCount`-1] for subsequent bound pipeline commands set by `pipelineBindPoint`. Set [`firstSet` + i] is bound to the descriptor buffer at binding `pBufferIndices`[i] at an offset of `pOffsets`[i]. Any bindings that were previously applied via these sets, or calls to vkCmdBindDescriptorSets, are no longer valid. Other sets will also be invalidated upon calling this command if `layout` differs from the pipeline layout used to bind those other sets, as described in Pipeline Layout Compatibility.

After binding descriptors, applications can modify descriptor memory either by performing writes on the host or with device commands. When descriptor memory is updated with device commands, visibility for the shader stage accessing a descriptor is ensured with the `VK_ACCESS_2_DESCRIPTOR_BUFFER_READ_BIT_EXT` access flag. Implementations must not access resources referenced by these descriptors unless they are dynamically accessed by shaders. Descriptors bound with this call can be undefined if they are not dynamically accessed by shaders.

Implementations may read descriptor data for any statically accessed descriptor if the `binding` in `layout` is not declared with the `VK_DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT` flag. If the `binding` in `layout` is declared with `VK_DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT`, implementations must not read descriptor data that is not dynamically accessed.

Applications must ensure that any descriptor which the implementation may read must be in-bounds of the underlying descriptor buffer binding.

| Note Applications can freely decide how large a variable descriptor buffer binding is, so it may not be safe to read such descriptor payloads statically. The intention of these rules is to allow implementations to speculatively prefetch descriptor payloads where feasible.

Dynamically accessing a resource through descriptor data from an unbound region of a sparse partially-resident buffer will result in invalid descriptor data being read, and therefore undefined behavior.

| Note For descriptors written by the host, visibility is implied through the automatic visibility operation on queue submit, and there is no need to consider `VK_ACCESS_2_DESCRIPTOR_BUFFER_READ_BIT`. Explicit synchronization for descriptors is only required when descriptors are updated on the device.

| Note The requirements above imply that all descriptor bindings have been defined with the equivalent of `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT`, `VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT` and `VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT`, but enabling those features is not required to get this behavior.

Valid Usage

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-None-08060
  The descriptorBuffer feature must be enabled

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-pOffsets-08061
  The offsets in `pOffsets` must be aligned to VkPhysicalDeviceDescriptorBufferPropertiesEXT::`descriptorBufferOffsetAlignment`

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-pOffsets-08063
  The offsets in `pOffsets` must be small enough such that any descriptor binding referenced by `layout` without the `VK_DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT` flag computes a valid address inside the underlying VkBuffer

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-pOffsets-08126
  The offsets in `pOffsets` must be small enough such that any location accessed by a shader as a sampler descriptor must be within VkPhysicalDeviceDescriptorBufferPropertiesEXT::`maxSamplerDescriptorBufferRange` of the sampler descriptor buffer binding

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-pOffsets-08127
  The offsets in `pOffsets` must be small enough such that any location accessed by a shader as a resource descriptor must be within VkPhysicalDeviceDescriptorBufferPropertiesEXT::`maxResourceDescriptorBufferRange` of the resource descriptor buffer binding

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-pBufferIndices-08064
  Each element of `pBufferIndices` must be less than VkPhysicalDeviceDescriptorBufferPropertiesEXT::`maxDescriptorBufferBindings`

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-pBufferIndices-08065
  Each element of `pBufferIndices` must reference a valid descriptor buffer binding set by a previous call to vkCmdBindDescriptorBuffersEXT in `commandBuffer`

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-firstSet-08066
  The sum of `firstSet` and `setCount` must be less than or equal to VkPipelineLayoutCreateInfo::`setLayoutCount` provided when `layout` was created

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-pipelineBindPoint-08067
  `pipelineBindPoint` must be supported by the `commandBuffer`’s parent `VkCommandPool`’s queue family

Valid Usage (Implicit)

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-commandBuffer-parameter
  `commandBuffer` must be a valid VkCommandBuffer handle

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-pipelineBindPoint-parameter
  `pipelineBindPoint` must be a valid VkPipelineBindPoint value

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-layout-parameter
  `layout` must be a valid VkPipelineLayout handle

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-pBufferIndices-parameter
  `pBufferIndices` must be a valid pointer to an array of `setCount` `uint32_t` values

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-pOffsets-parameter
  `pOffsets` must be a valid pointer to an array of `setCount` `VkDeviceSize` values

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-commandBuffer-recording
  `commandBuffer` must be in the recording state

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-commandBuffer-cmdpool
  The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-videocoding
  This command must only be called outside of a video coding scope

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-setCount-arraylength
  `setCount` must be greater than `0`

- VUID-vkCmdSetDescriptorBufferOffsetsEXT-commonparent
  Both of `commandBuffer`, and `layout` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Video Coding Scope | Supported Queue Types | Command Type
--- | --- | --- | --- | ---
Primary Secondary | Both | Outside | Graphics Compute | State

## See Also

VK_EXT_descriptor_buffer, VkCommandBuffer, `VkDeviceSize`, VkPipelineBindPoint, VkPipelineLayout

## Document Notes

For more information, see the Vulkan Specification

This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.

## Copyright

Copyright 2014-2022 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0