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<?xml version="1.0" encoding="UTF-8"?>
<!-- vi:set sw=2 ts=4: -->
<?xml-stylesheet href="../../extension.xsl" type="text/xsl"?>
<draft href="KHR_parallel_shader_compile/">
<name>KHR_parallel_shader_compile</name>
<contact> <a href="https://www.khronos.org/webgl/public-mailing-list/">WebGL
working group</a> (public_webgl 'at' khronos.org) </contact>
<contributors>
<contributor>Jie Chen, (jie.a.chen 'at' intel.com)</contributor>
<contributor>Geoff Lang, (geofflang 'at' google.com)</contributor>
<contributor>Members of the WebGL working group</contributor>
</contributors>
<number>37</number>
<depends>
<api version="1.0"/>
</depends>
<overview>
<mirrors href="https://www.khronos.org/registry/OpenGL/extensions/KHR/KHR_parallel_shader_compile.txt"
name="KHR_parallel_shader_compile">
</mirrors>
<features>
<feature>
Shader compilation and program linking may be performed in a separate CPU thread. This extension provides a mechanism for the application to provide a hint to limit the number of threads it wants to be used to compile shaders, as well as a query to determine if the compilation process is complete.
</feature>
</features>
</overview>
<idl xml:space="preserve">
[NoInterfaceObject]
interface KHR_parallel_shader_compile {
const GLenum MAX_SHADER_COMPILER_THREADS_KHR = 0x91B0;
const GLenum COMPLETION_STATUS_KHR = 0x91B1;
void maxShaderCompilerThreadsKHR(GLuint count);
};
</idl>
<samplecode xml:space="preserve">
<pre>
var canvas = document.createElement("canvas");
var gl = canvas.getContext("webgl");
var ext = gl.getExtension('KHR_parallel_shader_compile');
if (ext) {
// Just for demo of API usage. Generally it's not needed unless you really
// want to override the implementation-specific maximum.
var threads = gl.getParameter(ext.MAX_SHADER_COMPILER_THREADS_KHR);
ext.maxShaderCompilerThreadsKHR(Math.max(2, threads));
}
var vSource = "attribute vec2 position; void main() { gl_Position = vec4(position, 0, 1); }";
var fSource = "precision mediump float; void main() { gl_FragColor = vec4(1,0,0,1); }";
var vShader = gl.createShader(gl.VERTEX_SHADER);
gl.shaderSource(vShader, vSource);
gl.compileShader(vShader);
var fShader = gl.createShader(gl.FRAGMENT_SHADER);
gl.shaderSource(fShader, fSource);
gl.compileShader(fShader);
var program = gl.createProgram();
gl.attachShader(program, vShader);
gl.attachShader(program, fShader);
gl.linkProgram(program);
function checkToUseProgram() {
if (gl.getProgramParameter(program, gl.LINK_STATUS) == true) {
gl.useProgram(program);
} else {
// error check.
}
}
if (ext) {
function checkCompletion() {
if (gl.getProgramParameter(program, ext.COMPLETION_STATUS_KHR) == true) {
checkToUseProgram();
} else {
requestAnimationFrame(checkCompletion);
}
}
requestAnimationFrame(checkCompletion);
} else {
checkToUseProgram();
}
</pre>
</samplecode>
<history>
<revision date="2018/08/07">
<change>Initial revision.</change>
</revision>
<revision date="2018/09/14">
<change>Moved to draft status.</change>
</revision>
</history>
</draft>
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