| // Copyright 2017-2021 The Khronos Group, Inc. |
| // |
| // SPDX-License-Identifier: CC-BY-4.0 |
| |
| include::{generated}/meta/{refprefix}VK_KHR_shader_clock.txt[] |
| |
| === Other Extension Metadata |
| |
| *Last Modified Date*:: |
| 2019-4-25 |
| *IP Status*:: |
| No known IP claims. |
| *Interactions and External Dependencies*:: |
| - This extension requires |
| {spirv}/KHR/SPV_KHR_shader_clock.html[`SPV_KHR_shader_clock`]. |
| - This extension provides API support for |
| https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_shader_clock.txt[`ARB_shader_clock`] |
| and |
| https://github.com/KhronosGroup/GLSL/blob/master/extensions/ext/GL_EXT_shader_realtime_clock.txt[`EXT_shader_realtime_clock`] |
| *Contributors*:: |
| - Aaron Hagan, AMD |
| - Daniel Koch, NVIDIA |
| |
| === Description |
| |
| This extension advertises the SPIR-V code:ShaderClockKHR capability for |
| Vulkan, which allows a shader to query a real-time or monotonically |
| incrementing counter at the subgroup level or across the device level. |
| The two valid SPIR-V scopes for code:OpReadClockKHR are code:Subgroup and |
| code:Device. |
| |
| When using GLSL source-based shading languages, the code:clockRealtime*EXT() |
| timing functions map to the code:OpReadClockKHR instruction with a scope of |
| code:Device, and the code:clock*ARB() timing functions map to the |
| code:OpReadClockKHR instruction with a scope of code:Subgroup. |
| |
| include::{generated}/interfaces/VK_KHR_shader_clock.txt[] |
| |
| === New SPIR-V Capabilities |
| |
| * <<spirvenv-capabilities-table-ShaderClockKHR,ShaderClockKHR>> |
| |
| === Version History |
| |
| * Revision 1, 2019-4-25 (Aaron Hagan) |
| - Initial revision |
