Description

PrimitiveShadingRateKHR

Decorating a variable with the PrimitiveShadingRateKHR built-in decoration will make that variable contain the primitive fragment shading rate.

The value written to the variable decorated with PrimitiveShadingRateKHR by the last pre-rasterization shader stage in the pipeline is used as the primitive fragment shading rate. Outputs in previous shader stages are ignored.

If the last active pre-rasterization shader stage shader entry point’s interface does not include a variable decorated with PrimitiveShadingRateKHR, then it is as if the shader specified a fragment shading rate value of 0, indicating a horizontal and vertical rate of 1 pixel.

Valid Usage

  • VUID-PrimitiveShadingRateKHR-PrimitiveShadingRateKHR-04484
    The PrimitiveShadingRateKHR decoration must be used only within the MeshEXT, MeshNV, Vertex, or Geometry Execution Model

  • VUID-PrimitiveShadingRateKHR-PrimitiveShadingRateKHR-04485
    The variable decorated with PrimitiveShadingRateKHR must be declared using the Output Storage Class

  • VUID-PrimitiveShadingRateKHR-PrimitiveShadingRateKHR-04486
    The variable decorated with PrimitiveShadingRateKHR must be declared as a scalar 32-bit integer value for all supported execution models except MeshEXT

  • VUID-PrimitiveShadingRateKHR-PrimitiveShadingRateKHR-04487
    The value written to PrimitiveShadingRateKHR must include no more than one of Vertical2Pixels and Vertical4Pixels

  • VUID-PrimitiveShadingRateKHR-PrimitiveShadingRateKHR-04488
    The value written to PrimitiveShadingRateKHR must include no more than one of Horizontal2Pixels and Horizontal4Pixels

  • VUID-PrimitiveShadingRateKHR-PrimitiveShadingRateKHR-04489
    The value written to PrimitiveShadingRateKHR must not have any bits set other than those defined by Fragment Shading Rate Flags enumerants in the SPIR-V specification

  • VUID-PrimitiveShadingRateKHR-PrimitiveShadingRateKHR-07059
    The variable decorated with PrimitiveShadingRateKHR within the MeshEXT Execution Model must also be decorated with the PerPrimitiveEXT decoration

  • VUID-PrimitiveShadingRateKHR-PrimitiveShadingRateKHR-10598
    PrimitiveShadingRateKHR within the MeshEXT Execution Model must decorate a scalar 32-bit integer member of a structure decorated as Block, or decorate a variable of type OpTypeArray of 32-bit integer values

  • VUID-PrimitiveShadingRateKHR-PrimitiveShadingRateKHR-10599
    If PrimitiveShadingRateKHR is declared as an array of 32-bit integer values, within the MeshEXT Execution Model, size of the array must match the value specified by OutputPrimitivesEXT

  • VUID-PrimitiveShadingRateKHR-PrimitiveShadingRateKHR-10600
    If PrimitiveShadingRateKHR decorates a member of a structure, the variable declaration of the containing Block type must have an array size that matches the value specified by OutputPrimitivesEXT

  • VUID-PrimitiveShadingRateKHR-PrimitiveShadingRateKHR-12275
    If PrimitiveShadingRateKHR is declared in the MeshEXT Execution Model, the primitiveFragmentShadingRateMeshShader feature must be enabled

See Also

No cross-references are available

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 2014-2026 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0