# TessLevelOuter(3) Manual Page

## Name

TessLevelOuter - Outer tessellation levels

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## Description

`TessLevelOuter`

  Decorating a variable with the `TessLevelOuter` built-in decoration will make that variable contain the outer tessellation levels for the current patch.

  In tessellation control shaders, the variable decorated with `TessLevelOuter` can be written to, controlling the tessellation factors for the resulting patch. These values are used by the tessellator to control primitive tessellation and can be read by tessellation evaluation shaders.

  In tessellation evaluation shaders, the variable decorated with `TessLevelOuter` can read the values written by the tessellation control shader.

Valid Usage

- VUID-TessLevelOuter-TessLevelOuter-04390
  The `TessLevelOuter` decoration must be used only within the `TessellationControl` or `TessellationEvaluation` `Execution` `Model`

- VUID-TessLevelOuter-TessLevelOuter-04391
  The variable decorated with `TessLevelOuter` within the `TessellationControl` `Execution` `Model` must be declared using the `Output` `Storage` `Class`

- VUID-TessLevelOuter-TessLevelOuter-04392
  The variable decorated with `TessLevelOuter` within the `TessellationEvaluation` `Execution` `Model` must be declared using the `Input` `Storage` `Class`

- VUID-TessLevelOuter-TessLevelOuter-04393
  The variable decorated with `TessLevelOuter` must be declared as an array of size four, containing 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 2014-2024 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0