VkPhysicalDeviceMeshShaderPropertiesEXT(3)

# VkPhysicalDeviceMeshShaderPropertiesEXT(3) Manual Page

## Name

VkPhysicalDeviceMeshShaderPropertiesEXT - Structure describing mesh shading properties

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## C Specification

The `VkPhysicalDeviceMeshShaderPropertiesEXT` structure is defined as:

    // Provided by VK_EXT_mesh_shader
    typedef struct VkPhysicalDeviceMeshShaderPropertiesEXT {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           maxTaskWorkGroupTotalCount;
        uint32_t           maxTaskWorkGroupCount[3];
        uint32_t           maxTaskWorkGroupInvocations;
        uint32_t           maxTaskWorkGroupSize[3];
        uint32_t           maxTaskPayloadSize;
        uint32_t           maxTaskSharedMemorySize;
        uint32_t           maxTaskPayloadAndSharedMemorySize;
        uint32_t           maxMeshWorkGroupTotalCount;
        uint32_t           maxMeshWorkGroupCount[3];
        uint32_t           maxMeshWorkGroupInvocations;
        uint32_t           maxMeshWorkGroupSize[3];
        uint32_t           maxMeshSharedMemorySize;
        uint32_t           maxMeshPayloadAndSharedMemorySize;
        uint32_t           maxMeshOutputMemorySize;
        uint32_t           maxMeshPayloadAndOutputMemorySize;
        uint32_t           maxMeshOutputComponents;
        uint32_t           maxMeshOutputVertices;
        uint32_t           maxMeshOutputPrimitives;
        uint32_t           maxMeshOutputLayers;
        uint32_t           maxMeshMultiviewViewCount;
        uint32_t           meshOutputPerVertexGranularity;
        uint32_t           meshOutputPerPrimitiveGranularity;
        uint32_t           maxPreferredTaskWorkGroupInvocations;
        uint32_t           maxPreferredMeshWorkGroupInvocations;
        VkBool32           prefersLocalInvocationVertexOutput;
        VkBool32           prefersLocalInvocationPrimitiveOutput;
        VkBool32           prefersCompactVertexOutput;
        VkBool32           prefersCompactPrimitiveOutput;
    } VkPhysicalDeviceMeshShaderPropertiesEXT;

## Members

The members of the `VkPhysicalDeviceMeshShaderPropertiesEXT` structure describe the following implementation-dependent limits:

## Description

- `sType` is a VkStructureType value identifying this structure.

- `pNext` is `NULL` or a pointer to a structure extending this structure.

- `maxTaskWorkGroupTotalCount` is the maximum number of total local workgroups that can be launched by a single mesh tasks drawing command. See https://registry.khronos.org/vulkan/specs/1.3-extensions/html/vkspec.html#drawing-mesh-shading.

- `maxTaskWorkGroupCount`[3] is the maximum number of local workgroups that can be launched by a single mesh tasks drawing 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 drawing commands must be less than or equal to the corresponding limit. The product of these dimensions must be less than or equal to `maxTaskWorkGroupTotalCount`.

- `maxTaskWorkGroupInvocations` is the maximum total number of task shader invocations in a single local workgroup. The product of the X, Y, and Z sizes, as specified by the `LocalSize` or `LocalSizeId` execution mode in shader modules or by the object decorated by the `WorkgroupSize` decoration, must be less than or equal to this limit.

- `maxTaskWorkGroupSize`[3] is the maximum size of a local task workgroup, per dimension. These three values represent the maximum local workgroup size in the X, Y, and Z dimensions, respectively. The `x`, `y`, and `z` sizes, as specified by the `LocalSize` or `LocalSizeId` execution mode or by the object decorated by the `WorkgroupSize` decoration in shader modules, must be less than or equal to the corresponding limit.

- `maxTaskPayloadSize` is the maximum total storage size, in bytes, available for variables declared with the `TaskPayloadWorkgroupEXT` storage class in shader modules in the task shader stage.

- `maxTaskSharedMemorySize` is the maximum total storage size, in bytes, available for variables declared with the `Workgroup` storage class in shader modules in the task shader stage.

- `maxTaskPayloadAndSharedMemorySize` is the maximum total storage size, in bytes, available for variables that are declared with the `TaskPayloadWorkgroupEXT` or `Workgroup` storage class, in shader modules in the task shader stage.

- `maxMeshWorkGroupTotalCount` is the maximum number of local output tasks a single task shader workgroup can emit.

- `maxMeshWorkGroupCount`[3] is the maximum number of local output tasks a single task shader workgroup can emit, per dimension. These three values represent the maximum number of local output tasks for the X, Y, and Z dimensions, respectively. The workgroup count parameters to the `OpEmitMeshTasksEXT` must be less than or equal to the corresponding limit. The product of these dimensions must be less than or equal to `maxMeshWorkGroupTotalCount`.

- `maxMeshWorkGroupInvocations` is the maximum total number of mesh shader invocations in a single local workgroup. The product of the X, Y, and Z sizes, as specified by the `LocalSize` or `LocalSizeId` execution mode in shader modules or by the object decorated by the `WorkgroupSize` decoration, must be less than or equal to this limit.

- `maxMeshWorkGroupSize`[3] is the maximum size of a local mesh workgroup, per dimension. These three values represent the maximum local workgroup size in the X, Y, and Z dimensions, respectively. The `x`, `y`, and `z` sizes, as specified by the `LocalSize` or `LocalSizeId` execution mode or by the object decorated by the `WorkgroupSize` decoration in shader modules, must be less than or equal to the corresponding limit.

- `maxMeshSharedMemorySize` is the maximum total storage size, in bytes, available for variables declared with the `Workgroup` storage class in shader modules in the mesh shader stage.

- `maxMeshPayloadAndSharedMemorySize` is the maximum total storage size, in bytes, available for variables that are declared with the `TaskPayloadWorkgroupEXT` or `Workgroup` storage class in shader modules in the mesh shader stage.

- `maxMeshOutputMemorySize` is the maximum total storage size, in bytes, available for output variables in shader modules in the mesh shader stage, according to the formula in Mesh Shader Output.

- `maxMeshPayloadAndOutputMemorySize` is the maximum total storage size, in bytes, available for variables that are declared with the `TaskPayloadWorkgroupEXT` storage class, or output variables in shader modules in the mesh shader stage, according to the formula in Mesh Shader Output.

- `maxMeshOutputComponents` is the maximum number of components of output variables which can be output from the mesh shader stage.

- `maxMeshOutputVertices` is the maximum number of vertices which can be emitted by a single mesh shader workgroup.

- `maxMeshOutputPrimitives` is the maximum number of primitives which can be emitted by a single mesh shader workgroup.

- `maxMeshOutputLayers` is one greater than the maximum layer index that can be output from the mesh shader stage.

- `maxMeshMultiviewViewCount` is one greater than the maximum view index that can be used by any mesh shader.

- `meshOutputPerVertexGranularity` is the granularity of vertex allocation. The number of output vertices allocated for the mesh shader stage is padded to a multiple of this number. The value can be used to calculate the required storage size for output variables in shader modules in the mesh shader stage, which must be less than or equal to `maxMeshOutputMemorySize`.

- `meshOutputPerPrimitiveGranularity` is the granularity of primitive allocation. The number of output primitives allocated for the mesh shader stage is padded to a multiple of this number. The value can be used to calculate the required storage size for output variables in shader modules in the mesh shader stage, which must be less than or equal to `maxMeshOutputMemorySize`.

- `maxPreferredTaskWorkGroupInvocations` is the maximum number of task shader invocations in a single workgroup that is preferred by the implementation for optimal performance. The value is guaranteed to be a multiple of a supported subgroup size for the task shader stage.

- `maxPreferredMeshWorkGroupInvocations` is the maximum number of mesh shader invocations in a single workgroup that is preferred by the implementation for optimal performance. The value is guaranteed to be a multiple of a supported subgroup size for the mesh shader stage.

- `prefersLocalInvocationVertexOutput` specifies whether writes to the vertex output array in a mesh shader yield best performance when the array index matches `LocalInvocationIndex`.

- `prefersLocalInvocationPrimitiveOutput` specifies whether writes to the primitive output array in a mesh shader yield best performance when the array index matches `LocalInvocationIndex`.

- `prefersCompactVertexOutput` specifies whether output vertices should be compacted after custom culling in the mesh shader for best performance, otherwise keeping the vertices at their original location may be better.

- `prefersCompactPrimitiveOutput` specifies whether output primitives should be compacted after custom culling in the mesh shader for best performance, otherwise the use of `CullPrimitiveEXT` may be better.

If the `VkPhysicalDeviceMeshShaderPropertiesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- VUID-VkPhysicalDeviceMeshShaderPropertiesEXT-sType-sType
  `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MESH_SHADER_PROPERTIES_EXT`

## See Also

VK_EXT_mesh_shader, VkBool32, VkStructureType

## 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 2014-2023 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0