Web/API/KHR parallel shader compile

Draft This page is not complete.

The KHR_parallel_shader_compile extension is part of the WebGL API and enables a non-blocking poll operation, so that compile/link status availability (COMPLETION_STATUS_KHR) can be queried without potentially incurring stalls. In other words you can check the status of your shaders compiling without blocking the runtime.

WebGL extensions are available using the WebGLRenderingContext.getExtension() method. For more information, see also Using Extensions in the WebGL tutorial.

Constants

ext.COMPLETION_STATUS_KHR: A GLenum.

Examples

Enable the extension:

var ext = gl.getExtension('KHR_parallel_shader_compile');

In general, best practice with or without the extension is:

// Assuming lists of `shaders` and `programs`:
for (const x of shaders)
    gl.compileShader(x); // Never check compile status unless subsequent linking fails.
for (const x of programs)
    gl.linkProgram(x);

With the extension, apps would be able to poll whether programs have linked without janking, but these are likely to take the same total wall time to link:

// Generator yielding a progress ratio [0.0, 1.0].
// Without the extension, this will jank and only check one program per generation.
function* linkingProgress(programs) {
    const ext = gl.getExtension('KHR_parallel_shader_compile');
    let todo = programs.slice();
    while (todo.length) {
        if (ext) {
            todo = todo.filter(x => !gl.getProgramParameter(x, ext.COMPLETION_STATUS_KHR));
        } else {
            const x = todo.pop();
            gl.getProgramParameter(x, gl.LINK_STATUS);
        }
        if (!todo.length)
            return;
        yield 1.0 - (todo.length / programs.length);
    }
}

Specifications

Specification	Status	Comment
UnknownThe definition of 'KHR_parallel_shader_compile' in that specification.	Unknown	Initial definition.

Browser compatibility

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`KHR_parallel_shader_compile`	Chrome Full support 76	Edge Full support 79	Firefox Full support 80	IE No support No	Opera Full support 63	Safari ?	WebView Android Full support 76	Chrome Android Full support 76	Firefox Android No support No	Opera Android ?	Safari iOS ?	Samsung Internet Android Full support 12.0

Legend

Full support: Full support
No support: No support
Compatibility unknown: Compatibility unknown