Description

DrawIndex

Decorating a variable with the DrawIndex built-in will make that variable contain the integer value corresponding to the zero-based index of the draw that invoked the current task, mesh, or vertex shader invocation. For indirect drawing commands, DrawIndex begins at zero and increments by one for each draw executed. The number of draws is given by the drawCount parameter. For direct drawing commands, if vkCmdDrawMultiEXT or vkCmdDrawMultiIndexedEXT is used, this variable contains the integer value corresponding to the zero-based index of the draw. Otherwise DrawIndex is always zero. DrawIndex is dynamically uniform.

When task or mesh shaders are used, only the first active stage will have proper access to the variable. The value read by other stages is undefined.

Valid Usage

  • VUID-DrawIndex-DrawIndex-04207
    The DrawIndex decoration must be used only within the Vertex, MeshEXT, TaskEXT, MeshNV, or TaskNV Execution Model

  • VUID-DrawIndex-DrawIndex-04208
    The variable decorated with DrawIndex must be declared using the Input Storage Class

  • VUID-DrawIndex-DrawIndex-04209
    The variable decorated with DrawIndex 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 2014-2024 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0