dynamic_webgl_to_hw_accelerated_canvas.html

<!DOCTYPE html>
<html>
<body>
<script>
var canvas2D = document.createElement("canvas");
var ctx2D = canvas2D.getContext("2d");
var canvas3D = document.createElement('canvas');
var gl = canvas3D.getContext('webgl');
document.body.appendChild(canvas2D);
document.body.appendChild(canvas3D);

if (!gl)
    CanvasRunner.logFatalError("WebGL is not supported or enabled on this platform!");

var dummyCanvas2D = document.createElement("canvas");
var dummyCtx2D = dummyCanvas2D.getContext("2d");

function setSize(canvas2DWidth, canvas2DHeight, webglWidth, webglHeight) {
    canvas2D.width = canvas2DWidth;
    canvas2D.height = canvas2DHeight;
    dummyCanvas2D.width = canvas2DWidth;
    dummyCanvas2D.height = canvas2DWidth;
    canvas3D.width = webglWidth;
    canvas3D.height = webglHeight;
}

function rand(range) {
    return Math.floor(Math.random() * range);
}

function renderWebGL(gl) {
    gl.disable(gl.SCISSOR_TEST);
    gl.enable(gl.SCISSOR_TEST);
    gl.scissor(rand(1024), rand(1024), rand(1024), rand(1024));
    gl.clearColor(Math.random(), Math.random(), Math.random(), 1);
    gl.clear(gl.COLOR_BUFFER_BIT);
}

function doRun() {
    renderWebGL(gl);
    // draw dynamic WebGL
    ctx2D.drawImage(canvas3D, 0, 0);
}

function ensureComplete() {
    // Using destCanvas2D as a source image is just to flush out the content when
    // accelerated 2D canvas is in use.
    dummyCtx2D.drawImage(canvas2D, 0, 0, 1, 1, 0, 0, 1, 1);
}

function completeRun() {
    doRun();
    ensureComplete();
    requestAnimationFrame(completeRun);
}

window.onload = function () {
    setSize(1024, 1024, 1024, 1024);
    completeRun();
}

</script>
</body>
</html>
chromium/tools/perf/page_sets/simple_canvas/dynamic_webgl_to_hw_accelerated_canvas.html
