// Copyright (c) 2018-2020 NVIDIA Corporation
//
// SPDX-License-Identifier: CC-BY-4.0

include::{generated}/meta/{refprefix}VK_EXT_mesh_shader.adoc[]

=== Other Extension Metadata

*Last Modified Date*::
    2022-01-20
*Interactions and External Dependencies*::
  - This extension requires
    {spirv}/EXT/SPV_EXT_mesh_shader.html[`SPV_EXT_mesh_shader`]
  - This extension provides API support for
    https://github.com/KhronosGroup/GLSL/blob/master/extensions/ext/GLSL_EXT_mesh_shader.txt[`GLSL_EXT_mesh_shader`]
  - Interacts with Vulkan 1.1
  - Interacts with `apiext:VK_KHR_multiview`
  - Interacts with `apiext:VK_KHR_fragment_shading_rate`
*Contributors*::
  - Christoph Kubisch, NVIDIA
  - Pat Brown, NVIDIA
  - Jeff Bolz, NVIDIA
  - Daniel Koch, NVIDIA
  - Piers Daniell, NVIDIA
  - Pierre Boudier, NVIDIA
  - Patrick Mours, NVIDIA
  - David Zhao Akeley, NVIDIA
  - Kedarnath Thangudu, NVIDIA
  - Timur Kristóf, Valve
  - Hans-Kristian Arntzen, Valve
  - Philip Rebohle, Valve
  - Mike Blumenkrantz, Valve
  - Slawomir Grajewski, Intel
  - Michal Pietrasiuk, Intel
  - Mariusz Merecki, Intel
  - Tom Olson, ARM
  - Jan-Harald Fredriksen, ARM
  - Sandeep Kakarlapudi, ARM
  - Ruihao Zhang, QUALCOMM
  - Ricardo Garcia, Igalia, S.L.
  - Tobias Hector, AMD
  - Stu Smith, AMD


=== Description

This extension provides a new mechanism allowing applications to generate
collections of geometric primitives via programmable mesh shading.
It is an alternative to the existing programmable primitive shading
pipeline, which relied on generating input primitives by a fixed function
assembler as well as fixed function vertex fetch.

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

  * {spirv}/EXT/SPV_EXT_mesh_shader.html[`SPV_EXT_mesh_shader`]

include::{generated}/interfaces/VK_EXT_mesh_shader.adoc[]


=== New or Modified Built-In Variables

  * <<interfaces-builtin-variables-cullprimitive,CullPrimitiveEXT>>
  * <<interfaces-builtin-variables-primitivepointindices,PrimitivePointIndicesEXT>>
  * <<interfaces-builtin-variables-primitivelineindices,PrimitiveLineIndicesEXT>>
  * <<interfaces-builtin-variables-primitivetriangleindices,PrimitiveTriangleIndicesEXT>>
  * (modified)code:Position
  * (modified)code:PointSize
  * (modified)code:ClipDistance
  * (modified)code:CullDistance
  * (modified)code:PrimitiveId
  * (modified)code:Layer
  * (modified)code:ViewportIndex
  * (modified)code:NumWorkgroups
  * (modified)code:WorkgroupSize
  * (modified)code:WorkgroupId
  * (modified)code:LocalInvocationId
  * (modified)code:GlobalInvocationId
  * (modified)code:LocalInvocationIndex
  * (modified)code:NumSubgroups
  * (modified)code:SubgroupId
  * (modified)code:DrawIndex
  * (modified)code:PrimitiveShadingRateKHR
  * (modified)code:ViewIndex


=== New SPIR-V Capability

  * <<spirvenv-capabilities-table-MeshShadingEXT, code:MeshShadingEXT>>

=== Version History

  * Revision 1, 2022-03-08 (Christoph Kubisch, Daniel Koch, Patrick Mours)
  ** Initial revision