<!DOCTYPE HTML> <html> <head> <title>WebGL in OffscreenCanvas</title> <script src="/tests/SimpleTest/SimpleTest.js"></script> <link rel="stylesheet" href="/tests/SimpleTest/test.css"> </head> <body> <canvas id="c" width="64" height="64"></canvas> <script> SimpleTest.waitForExplicitFinish(); function runTest() { var htmlCanvas = document.getElementById("c"); var worker = new SharedWorker("offscreencanvas.js"); ok(htmlCanvas, "Should have HTML canvas element"); ok(worker, "Web worker successfully created"); ok(htmlCanvas.transferControlToOffscreen, "HTMLCanvasElement has transferControlToOffscreen function"); var offscreenCanvas = htmlCanvas.transferControlToOffscreen(); ok(offscreenCanvas, "Expected transferControlToOffscreen to succeed"); worker.port.start(); // We don't support transferring OffscreenCanvas via shared worker. SimpleTest.doesThrow( function() { worker.port.postMessage({test: 'webgl', canvas: offscreenCanvas}, [offscreenCanvas]); }, "OffscreenCanvas cannot transfer to shared worker" ); SimpleTest.finish(); } SpecialPowers.pushPrefEnv({'set': [ ['gfx.offscreencanvas.enabled', true], ['webgl.force-enabled', true], ]}, runTest); </script> </body> </html>