SPV_KHR_shader_ballot Is The First Cross-Vendor SPIR-V Extension

Last week marked the ratification of the first cross-vendor SPIR-V extension, the Khronos intermediate representation used by Vulkan and OpenCL 2.1+.

This first cross-vendor extension to SPIR-V is SPV_KHR_shader_ballot. This extension makes the changes to support the GL_ARB_shader_ballot extension within SPIR-V. ARB_shader_ballot in turn was added to the OpenGL 2015 extensions and is basically for cross-invocation communication.

SPV_KHR_shader_ballot was worked on by developers of NVIDIA, Google, Codeplay, and AMD. Those interested can find this extension documented via Khronos.org, "This extension provides new builtin variable decorations and instructions to support the OpenGL GL_ARB_shader_ballot extension in SPIR-V."

This is the first KHR (official Khronos) SPIR-V extension while the only other extensions in the SPIR-V registry are some AMD extensions.