# RayTmaxKHR(3) Manual Page

## Name

RayTmaxKHR - Maximum T value of a ray

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## Description

`RayTmaxKHR`

  A variable decorated with the `RayTmaxKHR` decoration will contain the parametric tmax value of the ray being processed. The value is independent of the space in which the ray origin and direction exist. The value is initialized to the parameter passed into the pipeline trace ray instruction.

  The tmax value changes throughout the lifetime of the ray that produced the intersection. In the closest hit shader, the value reflects the closest distance to the intersected primitive. In the any-hit shader, it reflects the distance to the primitive currently being intersected. In the intersection shader, it reflects the distance to the closest primitive intersected so far or the initial value. The value can change in the intersection shader after calling `OpReportIntersectionKHR` if the corresponding any-hit shader does not ignore the intersection. In a miss shader, the value is identical to the parameter passed into the pipeline trace ray instruction.

Valid Usage

- VUID-RayTmaxKHR-RayTmaxKHR-04348
  The `RayTmaxKHR` decoration must be used only within the `IntersectionKHR`, `AnyHitKHR`, `ClosestHitKHR`, or `MissKHR` `Execution` `Model`

- VUID-RayTmaxKHR-RayTmaxKHR-04349
  The variable decorated with `RayTmaxKHR` must be declared using the `Input` `Storage` `Class`

- VUID-RayTmaxKHR-RayTmaxKHR-04350
  The variable decorated with `RayTmaxKHR` must be declared as a scalar 32-bit floating-point 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 2014-2024 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0