| // Copyright (c) 2018-2020 NVIDIA Corporation |
| // |
| // SPDX-License-Identifier: CC-BY-4.0 |
| |
| include::{generated}/meta/{refprefix}VK_NV_compute_shader_derivatives.txt[] |
| |
| === Other Extension Metadata |
| |
| *Last Modified Date*:: |
| 2018-07-19 |
| *IP Status*:: |
| No known IP claims. |
| *Interactions and External Dependencies*:: |
| - This extension requires |
| {spirv}/NV/SPV_NV_compute_shader_derivatives.html[`SPV_NV_compute_shader_derivatives`] |
| - This extension provides API support for |
| https://github.com/KhronosGroup/GLSL/blob/master/extensions/nv/GLSL_NV_compute_shader_derivatives.txt[`GL_NV_compute_shader_derivatives`] |
| *Contributors*:: |
| - Pat Brown, NVIDIA |
| |
| === Description |
| |
| This extension adds Vulkan support for the |
| {spirv}/NV/SPV_NV_compute_shader_derivatives.html[`SPV_NV_compute_shader_derivatives`] |
| SPIR-V extension. |
| |
| The SPIR-V extension provides two new execution modes, both of which allow |
| compute shaders to use built-ins that evaluate compute derivatives |
| explicitly or implicitly. |
| Derivatives will be computed via differencing over a 2x2 group of shader |
| invocations. |
| The code:DerivativeGroupQuadsNV execution mode assembles shader invocations |
| into 2x2 groups, where each group has x and y coordinates of the local |
| invocation ID of the form (2m+{0,1}, 2n+{0,1}). |
| The code:DerivativeGroupLinearNV execution mode assembles shader invocations |
| into 2x2 groups, where each group has local invocation index values of the |
| form 4m+{0,1,2,3}. |
| |
| include::{generated}/interfaces/VK_NV_compute_shader_derivatives.txt[] |
| |
| === New SPIR-V Capability |
| |
| * <<spirvenv-capabilities-table-ComputeDerivativeGroupQuadsNV,ComputeDerivativeGroupQuadsNV>> |
| * <<spirvenv-capabilities-table-ComputeDerivativeGroupLinearNV,ComputeDerivativeGroupLinearNV>> |
| |
| === Issues |
| |
| (1) Should we specify that the groups of four shader invocations used for |
| derivatives in a compute shader are the same groups of four invocations that |
| form a "`quad`" in shader subgroups? |
| |
| *RESOLVED*: Yes. |
| |
| |
| === Examples |
| |
| None. |
| |
| === Version History |
| |
| * Revision 1, 2018-07-19 (Pat Brown) |
| - Initial draft |
