# HelperInvocation(3) Manual Page

## Name

HelperInvocation - Indication of whether a fragment shader is a helper invocation

Loading… please wait.

## Description

`HelperInvocation`

  Decorating a variable with the `HelperInvocation` built-in decoration will make that variable contain whether the current invocation is a helper invocation. This variable is non-zero if the current fragment being shaded is a helper invocation and zero otherwise. A helper invocation is an invocation of the shader that is produced to satisfy internal requirements such as the generation of derivatives.

Note | It is very likely that a helper invocation will have a value of `SampleMask` fragment shader input value that is zero.

Valid Usage

- VUID-HelperInvocation-HelperInvocation-04239
  The `HelperInvocation` decoration must be used only within the `Fragment` `Execution` `Model`

- VUID-HelperInvocation-HelperInvocation-04240
  The variable decorated with `HelperInvocation` must be declared using the `Input` `Storage` `Class`

- VUID-HelperInvocation-HelperInvocation-04241
  The variable decorated with `HelperInvocation` must be declared as a boolean 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 2014-2025 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0