This extension adds support for the following SPIR-V extension in Vulkan:

• SPV_KHR_shader_draw_parameters

The extension provides access to three additional built-in shader variables in Vulkan:

• BaseInstance, containing the firstInstance parameter passed to drawing commands,
• BaseVertex, containing the firstVertex or vertexOffset parameter passed to drawing commands, and
• DrawIndex, containing the index of the draw call currently being processed from an indirect drawing call.

When using GLSL source-based shader languages, the following variables from GL_ARB_shader_draw_parameters can map to these SPIR-V built-in decorations:

• in int gl_BaseInstanceARB; → BaseInstance,
• in int gl_BaseVertexARB; → BaseVertex, and
• in int gl_DrawIDARB; → DrawIndex.

Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1. However, the shaderDrawParameters feature bit was added to distinguish whether it is actually available or not.

VK_KHR_shader_draw_parameters

Name String

VK_KHR_shader_draw_parameters

Extension Type

Device extension

Registered Extension Number

64

Revision

1

Deprecation state

• Promoted to Vulkan 1.1

Contact

• Daniel Koch dgkoch

Other Extension Metadata

Last Modified Date

2017-09-05

IP Status

No known IP claims.

Interactions and External Dependencies

• This extension requires SPV_KHR_shader_draw_parameters
• This extension provides API support for GL_ARB_shader_draw_parameters
• Promoted to Vulkan 1.1 Core

Contributors

• Daniel Koch, NVIDIA Corporation
• Jeff Bolz, NVIDIA
• Daniel Rakos, AMD
• Jan-Harald Fredriksen, ARM
• John Kessenich, Google
• Stuart Smith, IMG