Name Strings

SPV_KHR_shader_draw_parameters

Contact

See Issues list in the Khronos SPIRV-Headers repository: https://github.com/KhronosGroup/SPIRV-Headers

Contributors

  • Piers Daniell, NVIDIA

  • Kerch Holt, NVIDIA

  • Daniel Koch, NVIDIA

  • Ashwin Kolhe, NVIDIA

Notice

Copyright (c) 2016 The Khronos Group Inc. Copyright terms at http://www.khronos.org/registry/speccopyright.html

Status

  • Complete.

  • Approved by the SPIR-V Working group: 2016-08-02

  • Approved by the Khronos Board of Promoters: 2016-09-30

Version

Last Modified Date

2016-09-20

Revision

6

Dependencies

This extension is written against the SPIR-V Specification, Version 1.1 Revision 1.

This extension requires SPIR-V 1.0.

Overview

This extension provides new built-in variables: BaseVertex, BaseInstance, and DrawIndex, to support the OpenGL GL_ARB_shader_draw_parameters extension in SPIR-V.

The new functionality is enabled under the DrawParameters capability.

Extension Name

To use this extension within a SPIR-V module, the following OpExtension must be present in the module:

OpExtension "SPV_KHR_shader_draw_parameters"

New Capabilities

This extension introduces a new capability:

DrawParameters

New Builtins

Builtin IDs added:

BaseVertex
BaseInstance
DrawIndex

New Instructions

None.

Token Number Assignments

BaseVertex

4424

BaseInstance

4425

DrawIndex

4426

DrawParameters

4427

Modifications to the SPIR-V Specification, Version 1.1

(Modify Section 3.21, BuiltIn to include new builtins)
BuiltIn Required Capability

4424

BaseVertex
Base vertex component of vertex ID. See OpenGL GL_ARB_shader_draw_parameters for more detail.

DrawParameters

4425

BaseInstance
Base instance component of instance ID. See OpenGL GL_ARB_shader_draw_parameters for more detail.

DrawParameters

4426

DrawIndex
Contains the index of the draw currently being processed. See OpenGL GL_ARB_shader_draw_parameters for more detail.

DrawParameters

(Modify Section 3.31, Capability, adding a row to the Capability table)
Capability Depends On

4427

DrawParameters

Shader

Validation Rules

An OpExtension must be added to the SPIR-V for validation layers to check legal use of this extension:

OpExtension "SPV_KHR_shader_draw_parameters"

Issues

None.

Revision History

Rev Date Author Changes

1

2016-05-31

Kerch Holt

Initial revision

2

2016-05-31

Kerch Holt

Removed "BuiltIn" from name (used in header not doc).

3

2016-08-07

Kerch Holt

Added extension number

4

2016-08-19

Daniel Koch

drawID → drawIndex, drop KHR and add DrawParameters

5

2016-09-02

Kerch Holt

Renumbered tokens as per GitLab issue #52 in SPIR-V

6

2016-09-20

Daniel Koch

Fix extension name in validation rules, standardize dates, remove extension number, update contributors