Position(3)

# Position(3) Manual Page

## Name

Position - Vertex position

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## Description

`Position`

  Decorating a variable with the `Position` built-in decoration will make that variable contain the position of the current vertex. In the last pre-rasterization shader stage, the value of the variable decorated with `Position` is used in subsequent primitive assembly, clipping, and rasterization operations.

| Note When `Position` decorates a variable in the `Input` `Storage` `Class`, it contains the data written to the output variable decorated with `Position` from the previous shader stage.

Valid Usage

- VUID-Position-Position-04318
  The `Position` decoration must be used only within the `MeshEXT`, `MeshNV`, `Vertex`, `TessellationControl`, `TessellationEvaluation`, or `Geometry` `Execution` `Model`

- VUID-Position-Position-04319
  The variable decorated with `Position` within the `MeshEXT`, `MeshNV`, or `Vertex` `Execution` `Model` must be declared using the `Output` `Storage` `Class`

- VUID-Position-Position-04320
  The variable decorated with `Position` within the `TessellationControl`, `TessellationEvaluation`, or `Geometry` `Execution` `Model` must not be declared using a `Storage` `Class` other than `Input` or `Output`

- VUID-Position-Position-04321
  The variable decorated with `Position` must be declared as a four-component vector of 32-bit floating-point values

## 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 2014-2022 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0