KHR_parallel_shader_compile

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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
Unknown
The definition of 'KHR_parallel_shader_compile' in that specification.
Unknown Initial definition.

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
KHR_parallel_shader_compileChrome Full support 76Edge Full support 79Firefox Full support 80IE No support NoOpera Full support 63Safari ? WebView Android Full support 76Chrome Android Full support 76Firefox Android No support NoOpera Android ? Safari iOS ? Samsung Internet Android Full support 12.0

Legend

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

See also