<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<script src="/tests/SimpleTest/SimpleTest.js"></script>
<link rel="stylesheet" href="/tests/SimpleTest/test.css">
<script src="webgl-util.js"></script>
<script src="es3-data.js"></script>
<title>WebGL test: test WEBGL_compressed_texture_etc extension</title>
<style>
img {
 border: 1px solid black;
 margin-right: 1em;
}
.testimages {
}

.testimages br {
  clear: both;
}

.testimages > div {
  float: left;
  margin: 1em;
}
</style>
</head>
<body>
<div id="description"></div>
<canvas id="canvas" width="8" height="8"></canvas>
<div id="console"></div>
<script id="vshader" type="x-shader/x-vertex">
    attribute vec4 vPosition;
    attribute vec2 texCoord0;
    varying vec2 texCoord;
    void main() {
        gl_Position = vPosition;
        texCoord = texCoord0;
    }
</script>
<script id="fshader" type="x-shader/x-fragment">
    precision mediump float;
    uniform sampler2D tex;
    varying vec2 texCoord;
    void main() {
        gl_FragData[0] = texture2D(tex, texCoord);
    }
</script>
<script id="fshader-r" type="x-shader/x-fragment">
    precision mediump float;
    uniform sampler2D tex;
    varying vec2 texCoord;
    void main() {
        vec4 pixel = (texture2D(tex, texCoord));
        pixel.r = (pixel.r + 1.0) / 2.0;
        gl_FragData[0] = pixel;
    }
</script>
<script id="fshader-rg" type="x-shader/x-fragment">
    precision mediump float;
    uniform sampler2D tex;
    varying vec2 texCoord;
    void main() {
        vec4 pixel = (texture2D(tex, texCoord));
        pixel.rg = (pixel.rg + 1.0) / 2.0;
        gl_FragData[0] = pixel;
    }
</script>
<script>
"use strict";
var ext = null;
var vao = null;
var gl = null;
var validFormats = {
    COMPRESSED_R11_EAC                        : 0x9270,
    COMPRESSED_SIGNED_R11_EAC                 : 0x9271,
    COMPRESSED_RG11_EAC                       : 0x9272,
    COMPRESSED_SIGNED_RG11_EAC                : 0x9273,
    COMPRESSED_RGB8_ETC2                      : 0x9274,
    COMPRESSED_SRGB8_ETC2                     : 0x9275,
    COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2  : 0x9276,
    COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2 : 0x9277,
    COMPRESSED_RGBA8_ETC2_EAC                 : 0x9278,
    COMPRESSED_SRGB8_ALPHA8_ETC2_EAC          : 0x9279,
};

function setupUnitQuad() {
    var vertexObject = gl.createBuffer();
    gl.bindBuffer(gl.ARRAY_BUFFER, vertexObject);
    gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([
         1.0,  1.0, 0.0,
        -1.0,  1.0, 0.0,
        -1.0, -1.0, 0.0,
         1.0,  1.0, 0.0,
        -1.0, -1.0, 0.0,
         1.0, -1.0, 0.0]), gl.STATIC_DRAW);
    gl.enableVertexAttribArray(0);
    gl.vertexAttribPointer(0, 3, gl.FLOAT, false, 0, 0);

    var vertexObject = gl.createBuffer();
    gl.bindBuffer(gl.ARRAY_BUFFER, vertexObject);
    gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([
        1.0, 1.0,
        0.0, 1.0,
        0.0, 0.0,
        1.0, 1.0,
        0.0, 0.0,
        1.0, 0.0]), gl.STATIC_DRAW);
    gl.enableVertexAttribArray(1);
    gl.vertexAttribPointer(1, 2, gl.FLOAT, false, 0, 0);
}

function runTest() {
    gl = canvas.getContext('webgl', {antialias: false});
    if (!gl) {
        ok(false, "WebGL context does not exist");
    } else {
        ok(true, "WebGL context exists");
        setupUnitQuad();

        // Run tests with extension disabled
        runTestDisabled();

        // Query the extension and store globally so shouldBe can access it
        ext = gl.getExtension("WEBGL_compressed_texture_etc");
        if (!ext) {
            ok(true, "No WEBGL_compressed_texture_etc support -- this is legal");
            runSupportedTest(false);
        } else {
            ok(true, "Successfully enabled WEBGL_compressed_texture_etc extension");

            runSupportedTest(true);
            runTestExtension();
        }
    }
    SimpleTest.finish();
}

function runSupportedTest(extensionEnabled) {
    var supported = gl.getSupportedExtensions();
    if (supported.includes("WEBGL_compressed_texture_etc")) {
        if (extensionEnabled) {
            ok(true, "WEBGL_compressed_texture_etc listed as supported and getExtension succeeded");
        } else {
            ok(false, "WEBGL_compressed_texture_etc listed as supported but getExtension failed");
        }
    } else {
        if (extensionEnabled) {
            ok(false, "WEBGL_compressed_texture_etc not listed as supported but getExtension succeeded");
        } else {
            ok(true, "WEBGL_compressed_texture_etc not listed as supported and getExtension failed -- this is legal");
        }
    }
}

function runTestDisabled() {
    is(gl.getParameter(gl.COMPRESSED_TEXTURE_FORMATS).length, 0,
       "Should be no compressed texture formats");
}

function formatExists(format, supportedFormats) {
    for (var ii = 0; ii < supportedFormats.length; ++ii) {
        if (format == supportedFormats[ii]) {
            ok(true, "supported format " + formatToString(format) + " is exists");
            return;
        }
    }
    ok(false, "supported format " + formatToString(format) + " does not exist");
}

function formatToString(format) {
    for (var p in ext) {
        if (ext[p] == format) {
            return p;
        }
    }
    return "0x" + format.toString(16);
}

function runTestExtension() {
    // check that all format enums exist.
    for (let name in validFormats) {
        is(ext[name], validFormats[name], "format is match");
    }

    let supportedFormats = gl.getParameter(gl.COMPRESSED_TEXTURE_FORMATS);
    // There should be exactly 10 formats
    is(supportedFormats.length, 10, "Should be exactly 10 formats");

    // check that all 10 formats exist
    for (let name in validFormats.length) {
        formatExists(validFormats[name], supportedFormats);
    }

    // Test each format
    testETC2_RGB();
}

function testETC2_RGB() {
    var tests = [
        {
            width: 4,
            height: 4,
            channels: 1,
            data: img_4x4_r11_eac,
            format: ext.COMPRESSED_R11_EAC
        },
        {
            width: 4,
            height: 4,
            channels: 1,
            data: img_4x4_signed_r11_eac,
            format: ext.COMPRESSED_SIGNED_R11_EAC
        },
        {
            width: 4,
            height: 4,
            channels: 2,
            data: img_4x4_rg11_eac,
            format: ext.COMPRESSED_RG11_EAC
        },
        {
            width: 4,
            height: 4,
            channels: 2,
            data: img_4x4_signed_rg11_eac,
            format: ext.COMPRESSED_SIGNED_RG11_EAC
        },
        {
            width: 4,
            height: 4,
            channels: 3,
            data: img_4x4_rgb_etc2,
            format: ext.COMPRESSED_RGB8_ETC2
        },
        {
            width: 4,
            height: 4,
            channels: 3,
            data: img_4x4_rgb_etc2,
            format: ext.COMPRESSED_SRGB8_ETC2
        },
        {
            width: 4,
            height: 4,
            channels: 4,
            data: img_4x4_rgb_punchthrough_etc2,
            format: ext.COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2
        },
        {
            width: 4,
            height: 4,
            channels: 4,
            data: img_4x4_rgb_punchthrough_etc2,
            format: ext.COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2
        },
        {
            width: 4,
            height: 4,
            channels: 4,
            data: img_4x4_rgba_etc2,
            format: ext.COMPRESSED_RGBA8_ETC2_EAC
        },
        {
            width: 4,
            height: 4,
            channels: 4,
            data: img_4x4_rgba_etc2,
            format: ext.COMPRESSED_SRGB8_ALPHA8_ETC2_EAC
        },
        {
            width: 8,
            height: 8,
            channels: 1,
            data: img_8x8_r11_eac,
            format: ext.COMPRESSED_R11_EAC
        },
        {
            width: 8,
            height: 8,
            channels: 1,
            data: img_8x8_signed_r11_eac,
            format: ext.COMPRESSED_SIGNED_R11_EAC
        },
        {
            width: 8,
            height: 8,
            channels: 2,
            data: img_8x8_rg11_eac,
            format: ext.COMPRESSED_RG11_EAC
        },
        {
            width: 8,
            height: 8,
            channels: 2,
            data: img_8x8_signed_rg11_eac,
            format: ext.COMPRESSED_SIGNED_RG11_EAC
        },
        {
            width: 8,
            height: 8,
            channels: 3,
            data: img_8x8_rgb_etc2,
            format: ext.COMPRESSED_RGB8_ETC2
        },
        {
            width: 8,
            height: 8,
            channels: 3,
            data: img_8x8_rgb_etc2,
            format: ext.COMPRESSED_SRGB8_ETC2
        },
        {
            width: 8,
            height: 8,
            channels: 4,
            data: img_8x8_rgb_punchthrough_etc2,
            format: ext.COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2
        },
        {
            width: 8,
            height: 8,
            channels: 4,
            data: img_8x8_rgb_punchthrough_etc2,
            format: ext.COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2
        },
        {
            width: 8,
            height: 8,
            channels: 4,
            data: img_8x8_rgba_etc2,
            format: ext.COMPRESSED_RGBA8_ETC2_EAC
        },
        {
            width: 8,
            height: 8,
            channels: 4,
            data: img_8x8_rgba_etc2,
            format: ext.COMPRESSED_SRGB8_ALPHA8_ETC2_EAC
        },
        {
            width: 32,
            height: 32,
            channels: 1,
            data: img_32x32_r11_eac,
            format: ext.COMPRESSED_R11_EAC
        },
        {
            width: 32,
            height: 32,
            channels: 1,
            data: img_32x32_signed_r11_eac,
            format: ext.COMPRESSED_SIGNED_R11_EAC
        },
        {
            width: 32,
            height: 32,
            channels: 2,
            data: img_32x32_rg11_eac,
            format: ext.COMPRESSED_RG11_EAC
        },
        {
            width: 32,
            height: 32,
            channels: 2,
            data: img_32x32_signed_rg11_eac,
            format: ext.COMPRESSED_SIGNED_RG11_EAC
        },
        {
            width: 32,
            height: 32,
            channels: 3,
            data: img_32x32_rgb_etc2,
            format: ext.COMPRESSED_RGB8_ETC2
        },
        {
            width: 32,
            height: 32,
            channels: 3,
            data: img_32x32_rgb_etc2,
            format: ext.COMPRESSED_SRGB8_ETC2
        },
        {
            width: 32,
            height: 32,
            channels: 4,
            data: img_32x32_rgb_punchthrough_etc2,
            format: ext.COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2
        },
        {
            width: 32,
            height: 32,
            channels: 4,
            data: img_32x32_rgb_punchthrough_etc2,
            format: ext.COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2
        },
        {
            width: 32,
            height: 32,
            channels: 4,
            data: img_32x32_rgba_etc2,
            format: ext.COMPRESSED_RGBA8_ETC2_EAC
        },
        {
            width: 32,
            height: 32,
            channels: 4,
            data: img_32x32_rgba_etc2,
            format: ext.COMPRESSED_SRGB8_ALPHA8_ETC2_EAC
        },
    ];
    testETCTextures(tests);
}

function testETCTextures(tests) {
    for (var ii = 0; ii < tests.length; ++ii) {
        testETCTexture(tests[ii]);
    }
}

/* Return the size of block in bytes */
function getBlockSize(format) {
    switch (format) {
    case ext.COMPRESSED_R11_EAC:
    case ext.COMPRESSED_SIGNED_R11_EAC:
    case ext.COMPRESSED_RGB8_ETC2:
    case ext.COMPRESSED_SRGB8_ETC2:
    case ext.COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2:
    case ext.COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2:
        return 8;
    case ext.COMPRESSED_RG11_EAC:
    case ext.COMPRESSED_SIGNED_RG11_EAC:
    case ext.COMPRESSED_RGBA8_ETC2_EAC:
    case ext.COMPRESSED_SRGB8_ALPHA8_ETC2_EAC:
        return 16
    }
}

function copyRect(data, srcX, srcY, dstX, dstY, width, height, stride) {
  var bytesPerLine = width * 4;
  var srcOffset = srcX * 4 + srcY * stride;
  var dstOffset = dstX * 4 + dstY * stride;
  for (var jj = height; jj > 0; --jj) {
    for (var ii = 0; ii < bytesPerLine; ++ii) {
      data[dstOffset + ii] = data[srcOffset + ii];
    }
    srcOffset += stride;
    dstOffset += stride;
  }
}

function testETCTexture(test) {
    var data = new Uint8Array(test.data.compressed);
    var width = test.width;
    var height = test.height;
    var format = test.format;

    var uncompressedData = new Uint8Array(test.data.decompressed);
    var glErrorShouldBe = (glInner, glError, msg) => {
        msg = msg || "";
        var err = glInner.getError();
        var getGLErrorAsString = error => {
            if (error === glInner.NO_ERROR) {
                return "NO_ERROR";
            }
            for (let name in glInner) {
                if (glInner[name] === error) {
                    return name;
                }
            }
            return error.toString();
        }

        if (err != glError) {
            ok(false, "getError expected: " + getGLErrorAsString(glError) +
                      ". Was " + getGLErrorAsString(err) + " : " + msg);
        } else {
            ok(true, "getError was expected value: " +
                     getGLErrorAsString(glError) + " : " + msg);
        }
    };

    canvas.width = width;
    canvas.height = height;
    gl.viewport(0, 0, width, height);

    var tex = gl.createTexture();
    gl.bindTexture(gl.TEXTURE_2D, tex);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
    gl.compressedTexImage2D(gl.TEXTURE_2D, 0, format, width, height, 0, data);
    glErrorShouldBe(gl, gl.NO_ERROR, "uploading compressed texture");
    gl.generateMipmap(gl.TEXTURE_2D);
    glErrorShouldBe(gl, gl.INVALID_OPERATION, "trying to generate mipmaps from compressed texture");
    if (format == ext.COMPRESSED_SIGNED_R11_EAC) {
      var program = WebGLUtil.createProgramByIds(gl, 'vshader', 'fshader-r');
    } else if (format == ext.COMPRESSED_SIGNED_RG11_EAC) {
      var program = WebGLUtil.createProgramByIds(gl, 'vshader', 'fshader-rg');
    } else {
      var program = WebGLUtil.createProgramByIds(gl, 'vshader', 'fshader');
    }
    gl.bindAttribLocation(program, 0, 'vPosition');
    gl.bindAttribLocation(program, 1, 'texCoord0');
    gl.useProgram(program);

    gl.clearColor(1.0, 1.0, 1.0, 1.0);
    gl.clear(gl.COLOR_BUFFER_BIT);
    gl.drawArrays(gl.TRIANGLES, 0, 6);
    compareRect(width, height, test.channels, width, height, uncompressedData, data, format);

    gl.compressedTexImage2D(gl.TEXTURE_2D, 0, format, width, height, 1, data);
    glErrorShouldBe(gl, gl.INVALID_VALUE, "non 0 border");

    gl.compressedTexImage2D(gl.TEXTURE_2D, 0, format, width + 4, height, 0, data);
    glErrorShouldBe(gl, gl.INVALID_VALUE, "data size does not match dimensions");
    gl.compressedTexImage2D(gl.TEXTURE_2D, 0, format, width, height + 4, 0, data);
    glErrorShouldBe(gl, gl.INVALID_VALUE, "data size does not match dimensions");
    gl.compressedTexImage2D(gl.TEXTURE_2D, 0, format, width - 4, height, 0, data);
    glErrorShouldBe(gl, gl.INVALID_VALUE, "data size does not match dimensions");
    gl.compressedTexImage2D(gl.TEXTURE_2D, 0, format, width, height - 4, 0, data);
    glErrorShouldBe(gl, gl.INVALID_VALUE, "data size does not match dimensions");

    gl.compressedTexImage2D(gl.TEXTURE_2D, 0, format, width - 1, height, 0, data);
    glErrorShouldBe(gl, gl.NO_ERROR, "non multiple-of-4 supported");
    gl.compressedTexImage2D(gl.TEXTURE_2D, 0, format, width - 2, height, 0, data);
    glErrorShouldBe(gl, gl.NO_ERROR, "non multiple-of-4 supported");
    gl.compressedTexImage2D(gl.TEXTURE_2D, 0, format, width, height - 1, 0, data);
    glErrorShouldBe(gl, gl.NO_ERROR, "non multiple-of-4 supported");
    gl.compressedTexImage2D(gl.TEXTURE_2D, 0, format, width, height - 2, 0, data);
    glErrorShouldBe(gl, gl.NO_ERROR, "non multiple-of-4 supported");

    if (width == 4) {
        gl.compressedTexImage2D(gl.TEXTURE_2D, 1, format, 1, height, 0, data);
        glErrorShouldBe(gl, gl.NO_ERROR, "valid dimensions for level > 0");
        gl.compressedTexImage2D(gl.TEXTURE_2D, 1, format, 2, height, 0, data);
        glErrorShouldBe(gl, gl.NO_ERROR, "valid dimensions for level > 0");
    }
    if (height == 4) {
        gl.compressedTexImage2D(gl.TEXTURE_2D, 1, format, width, 1, 0, data);
        glErrorShouldBe(gl, gl.NO_ERROR, "valid dimensions for level > 0");
        gl.compressedTexImage2D(gl.TEXTURE_2D, 1, format, width, 2, 0, data);
        glErrorShouldBe(gl, gl.NO_ERROR, "valid dimensions for level > 0");
    }

    // pick a wrong format that uses the same amount of data.
    var wrongFormat;
    switch (format) {
    case ext.COMPRESSED_R11_EAC:
        wrongFormat = ext.COMPRESSED_SIGNED_R11_EAC;
        break;
    case ext.COMPRESSED_SIGNED_R11_EAC:
        wrongFormat = ext.COMPRESSED_R11_EAC;
        break;
    case ext.COMPRESSED_RG11_EAC:
        wrongFormat = ext.COMPRESSED_SIGNED_RG11_EAC;
        break;
    case ext.COMPRESSED_SIGNED_RG11_EAC:
        wrongFormat = ext.COMPRESSED_RG11_EAC;
        break;
    case ext.COMPRESSED_RGB8_ETC2:
        wrongFormat = ext.COMPRESSED_SRGB8_ETC2;
        break;
    case ext.COMPRESSED_SRGB8_ETC2:
        wrongFormat = ext.COMPRESSED_RGB8_ETC2;
        break;
    case ext.COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2:
        wrongFormat = ext.COMPRESSED_RGB8_ETC2;
        break;
    case ext.COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2:
        wrongFormat = ext.COMPRESSED_RGB8_ETC2;
        break;
    case ext.COMPRESSED_RGBA8_ETC2_EAC:
        wrongFormat = ext.COMPRESSED_SRGB8_ALPHA8_ETC2_EAC;
        break;
    case ext.COMPRESSED_SRGB8_ALPHA8_ETC2_EAC:
        wrongFormat = ext.COMPRESSED_RGBA8_ETC2_EAC;
        break;
    }

    // Restore original texture.
    gl.compressedTexImage2D(gl.TEXTURE_2D, 0, format, width, height, 0, data);
    glErrorShouldBe(gl, gl.NO_ERROR, "uploading compressed texture");

    gl.compressedTexSubImage2D(gl.TEXTURE_2D, 0, 0, 0, width, height, wrongFormat, data);
    glErrorShouldBe(gl, gl.INVALID_OPERATION, "format does not match");

    gl.compressedTexSubImage2D(gl.TEXTURE_2D, 0, 0, 0, width + 4, height, format, data);
    glErrorShouldBe(gl, gl.INVALID_VALUE, "data size does not match dimensions");
    gl.compressedTexSubImage2D(gl.TEXTURE_2D, 0, 0, 0, width, height + 4, format, data);
    glErrorShouldBe(gl, gl.INVALID_VALUE, "data size does not match dimensions");
    gl.compressedTexSubImage2D(gl.TEXTURE_2D, 0, 0, 0, width - 4, height, format, data);
    glErrorShouldBe(gl, gl.INVALID_VALUE, "data size does not match dimensions");
    gl.compressedTexSubImage2D(gl.TEXTURE_2D, 0, 0, 0, width, height - 4, format, data);
    glErrorShouldBe(gl, gl.INVALID_VALUE, "data size does not match dimensions");

    gl.compressedTexImage2D(gl.TEXTURE_2D, 0, format, width, height, 0, data);
    glErrorShouldBe(gl, gl.NO_ERROR, "uploading compressed texture");
    gl.compressedTexSubImage2D(gl.TEXTURE_2D, 0, 0, 0, width - 1, height, format, data);
    glErrorShouldBe(gl, gl.INVALID_OPERATION, "invalid dimensions");
    gl.compressedTexSubImage2D(gl.TEXTURE_2D, 0, 0, 0, width - 2, height, format, data);
    glErrorShouldBe(gl, gl.INVALID_OPERATION, "invalid dimensions");
    gl.compressedTexSubImage2D(gl.TEXTURE_2D, 0, 0, 0, width, height - 1, format, data);
    glErrorShouldBe(gl, gl.INVALID_OPERATION, "invalid dimensions");
    gl.compressedTexSubImage2D(gl.TEXTURE_2D, 0, 0, 0, width, height - 2, format, data);
    glErrorShouldBe(gl, gl.INVALID_OPERATION, "invalid dimensions");

    var subData = new Uint8Array(data.buffer, 0, getBlockSize(format));

    if (width == 8 && height == 8) {
        gl.compressedTexSubImage2D(gl.TEXTURE_2D, 0, 1, 0, 4, 4, format, subData);
        glErrorShouldBe(gl, gl.INVALID_OPERATION, "invalid offset");
        gl.compressedTexSubImage2D(gl.TEXTURE_2D, 0, 0, 1, 4, 4, format, subData);
        glErrorShouldBe(gl, gl.INVALID_OPERATION, "invalid offset");
    }

    if (width < 32 && height < 32) {
        var stride = width * 4;
        for (var yoff = 0; yoff < height; yoff += 4) {
            for (var xoff = 0; xoff < width; xoff += 4) {
                copyRect(uncompressedData, 0, 0, xoff, yoff, 4, 4, stride);
                gl.compressedTexSubImage2D(gl.TEXTURE_2D, 0, xoff, yoff, 4, 4, format, subData);
                glErrorShouldBe(gl, gl.NO_ERROR, "uploading compressed texture");
                gl.clearColor(1.0, 1.0, 1.0, 1.0);
                gl.clear(gl.COLOR_BUFFER_BIT);
                gl.drawArrays(gl.TRIANGLES, 0, 6);
                compareRect(width, height, test.channels, width, height, uncompressedData, data, format);
            }
        }
    }
}

function insertImg(element, caption, img) {
    var div = document.createElement("div");
    div.appendChild(img);
    var label = document.createElement("div");
    label.appendChild(document.createTextNode(caption));
    div.appendChild(label);
    element.appendChild(div);
}

function convertToSRGB(val) {
    var norm = val / 255.0;
    var res = 0;
    if (norm <= 0.04045) {
        res = norm / 12.92;
    } else {
        res = Math.pow(((norm + 0.055)/1.055), 2.4);
    }

    return res * 255.0;
}

function makeImage(imageWidth, imageHeight, dataWidth, data, alpha) {
    var scale = 8;
    var c = document.createElement("canvas");
    c.width = imageWidth * scale;
    c.height = imageHeight * scale;
    var ctx = c.getContext("2d");
    for (var yy = 0; yy < imageHeight; ++yy) {
        for (var xx = 0; xx < imageWidth; ++xx) {
            var offset = (yy * dataWidth + xx) * 4;
            ctx.fillStyle = "rgba(" +
                    data[offset + 0] + "," +
                    data[offset + 1] + "," +
                    data[offset + 2] + "," +
                    (alpha ? data[offset + 3] / 255 : 1) + ")";
            ctx.fillRect(xx * scale, yy * scale, scale, scale);
        }
    }
    var img = document.createElement("img");
    img.src = c.toDataURL();
    return img;
}

function compareRect(actualWidth, actualHeight, actualChannels,
                     dataWidth, dataHeight, expectedData,
                     testData, testFormat)
{
    var actual = new Uint8Array(actualWidth * actualHeight * 4);
    gl.readPixels(
            0, 0, actualWidth, actualHeight, gl.RGBA, gl.UNSIGNED_BYTE, actual);

    var div = document.createElement("div");
    div.className = "testimages";
    var hasAlpha = actualChannels == 4;
    var imgExpected = makeImage(actualWidth, actualHeight, dataWidth, expectedData, hasAlpha);
    var imgActual = makeImage(actualWidth, actualHeight, actualWidth, actual, hasAlpha);
    insertImg(div, "expected", imgExpected);
    insertImg(div, "actual", imgActual);
    div.appendChild(document.createElement('br'));
    document.getElementById("console").appendChild(div);

    var failed = false;
    for (var yy = 0; yy < actualHeight; ++yy) {
        for (var xx = 0; xx < actualWidth; ++xx) {
            var actualOffset = (yy * actualWidth + xx) * 4;
            var expectedOffset = (yy * dataWidth + xx) * 4;
            var expected = expectedData.slice(expectedOffset, expectedOffset + 4);

            var maxDiffPixel = 0;
            switch (testFormat) {
              case ext.COMPRESSED_SRGB8_ETC2:
              case ext.COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2:
              case ext.COMPRESSED_SRGB8_ALPHA8_ETC2_EAC:

                  // Alpha shouldn't do conversion.
                  for (var i = 0; i < 3; ++i) {
                      expected[i] = convertToSRGB(expected[i]);
                  }
                  //fallthrough
              case ext.COMPRESSED_R11_EAC:
              case ext.COMPRESSED_RG11_EAC:
              case ext.COMPRESSED_SIGNED_R11_EAC:
              case ext.COMPRESSED_SIGNED_RG11_EAC:
                  // Due to floating round error, we need fuzzy test here.
                  var maxDiffPixel = 1;
                  break;
              default:
                  var maxDiffPixel = 0;
                  break;
            }

            for (var channel = 0; channel < actualChannels; ++channel) {
                var diff = Math.abs(expected[channel] - actual[actualOffset + channel]);

                if (diff > maxDiffPixel) {
                    failed = true;
                    var was = actual.slice(actualOffset, actualOffset + 4).join();
                    ok(false, 'at (' + xx + ', ' + yy +
                              ') expected: ' + expected.join() + ' was ' + was);
                    break;
                }
            }
        }
    }
    if (!failed) {
        ok(true, "texture rendered correctly");
    }
}

var prefArrArr = [
  ['webgl.enable-draft-extensions', true],
];
var prefEnv = {'set': prefArrArr};
SimpleTest.waitForExplicitFinish();
SpecialPowers.pushPrefEnv(prefEnv, runTest);
</script>
</body>
</html>
