# BaseVertex(3) Manual Page

## Name

BaseVertex - First vertex being rendered

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## Description

`BaseVertex`

  Decorating a variable with the `BaseVertex` built-in will make that variable contain the integer value corresponding to the first vertex or vertex offset that was passed to the command that invoked the current vertex shader invocation. For non-indexed drawing commands, this variable is the `firstVertex` parameter to a direct drawing command or the `firstVertex` member of the structure consumed by an indirect drawing command. For indexed drawing commands, this variable is the `vertexOffset` parameter to a direct drawing command or the `vertexOffset` member of the structure consumed by an indirect drawing command.

Valid Usage

- VUID-BaseVertex-BaseVertex-04184
  The `BaseVertex` decoration must be used only within the `Vertex` `Execution` `Model`

- VUID-BaseVertex-BaseVertex-04185
  The variable decorated with `BaseVertex` must be declared using the `Input` `Storage` `Class`

- VUID-BaseVertex-BaseVertex-04186
  The variable decorated with `BaseVertex` must be declared as a scalar 32-bit integer 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