offscreencanvas-transfer-image-bitmap.js

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function testTransferToImageBitmap(webglContextVersion, bitmap) {

    var internalFormat = "RGBA";

    var pixelFormat = "RGBA";

    var pixelType = "UNSIGNED_BYTE";

    var width = 32;

    var height = 32;

    var canvas = document.createElement("canvas");

    canvas.width = width;

    canvas.height = height;

    var gl = WebGLTestUtils.create3DContext(canvas);

    gl.clearColor(0,0,0,1);

    gl.clearDepth(1);

    gl.disable(gl.BLEND);

    TexImageUtils.setupTexturedQuad(gl, internalFormat);

    gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

    // Enable writes to the RGBA channels

    gl.colorMask(1, 1, 1, 0);

    var texture = gl.createTexture();

    // Bind the texture to texture unit 0

    gl.bindTexture(gl.TEXTURE_2D, texture);

    // Set up texture parameters

    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);

    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);

    var targets = [gl.TEXTURE_2D];

    // Upload the image into the texture

    for (var tt = 0; tt < targets.length; ++tt) {

        gl.texImage2D(targets[tt], 0, gl[internalFormat], gl[pixelFormat], gl[pixelType], bitmap);

    for (var tt = 0; tt < targets.length; ++tt) {

        // Draw the triangles

        gl.clearColor(0, 0, 0, 1);

        gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

        gl.drawArrays(gl.TRIANGLES, 0, 6);

        var buf = new Uint8Array(width * height * 4);

        gl.readPixels(0, 0, width, height, gl.RGBA, gl.UNSIGNED_BYTE, buf);

        _checkCanvas(buf, width, height, webglContextVersion);

function _checkCanvas(buf, width, height, webglContextVersion)

    for (var i = 0; i < width * height; i++) {

        if (buf[i * 4] != 255 || buf[i * 4 + 1] != 255 ||

            buf[i * 4 + 2] != 0 || buf[i * 4 + 3] != 255) {

            testFailed("OffscreenCanvas." + webglContextVersion +

                ": This pixel should be [255, 255, 0, 255], but it is: [" + buf[i * 4] + ", " +

                buf[i * 4 + 1] + ", " + buf[i * 4 + 2] + ", " + buf[i * 4 + 3] + "].");

            return;

    testPassed("TransferToImageBitmap test on OffscreenCanvas." + webglContextVersion + " passed");