# LaunchIdKHR(3) Manual Page

## Name

LaunchIdKHR - Launch Id for ray shaders

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## Description

`LaunchIdKHR`

  A variable decorated with the `LaunchIdKHR` decoration will specify the index of the work item being processed. One work item is generated for each of the `width` × `height` × `depth` items dispatched by a vkCmdTraceRaysKHR or vkCmdTraceRaysNV command. All shader invocations inherit the same value for variables decorated with `LaunchIdKHR`.

Valid Usage

- VUID-LaunchIdKHR-LaunchIdKHR-04266
  The `LaunchIdKHR` decoration must be used only within the `RayGenerationKHR`, `IntersectionKHR`, `AnyHitKHR`, `ClosestHitKHR`, `MissKHR`, or `CallableKHR` `Execution` `Model`

- VUID-LaunchIdKHR-LaunchIdKHR-04267
  The variable decorated with `LaunchIdKHR` must be declared using the `Input` `Storage` `Class`

- VUID-LaunchIdKHR-LaunchIdKHR-04268
  The variable decorated with `LaunchIdKHR` must be declared as a three-component vector of 32-bit integer 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