PatchVertices(3)

# PatchVertices(3) Manual Page

## Name

PatchVertices - Number of vertices in an input patch

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## Description

`PatchVertices`

  Decorating a variable with the `PatchVertices` built-in decoration will make that variable contain the number of vertices in the input patch being processed by the shader. In a Tessellation Control Shader, this is the same as the name:patchControlPoints member of VkPipelineTessellationStateCreateInfo. In a Tessellation Evaluation Shader, `PatchVertices` is equal to the tessellation control output patch size. When the same shader is used in different pipelines where the patch sizes are configured differently, the value of the `PatchVertices` variable will also differ.

Valid Usage

- VUID-PatchVertices-PatchVertices-04308
  The `PatchVertices` decoration must be used only within the `TessellationControl` or `TessellationEvaluation` `Execution` `Model`

- VUID-PatchVertices-PatchVertices-04309
  The variable decorated with `PatchVertices` must be declared using the `Input` `Storage` `Class`

- VUID-PatchVertices-PatchVertices-04310
  The variable decorated with `PatchVertices` must be declared as a scalar 32-bit integer value

## 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 2014-2023 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0