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<canvas id="renderCanvas" width="250" height="250"></canvas>

#renderCanvas {
    border: 5px solid #aaaaaa;
}

var vertexShaderSource =
    `
    attribute vec2 a_Position;
    attribute vec2 a_TexCoord;
    uniform mat4 u_ModelMatrix;
    varying vec2 v_TexCoord;

    void main()
    {
        gl_Position = u_ModelMatrix * vec4(a_Position, 0.0, 1.0);
        v_TexCoord = a_TexCoord;
    }`;

var fragmentShaderSource =
    `
    precision mediump float;
    uniform sampler2D u_Sampler;
    varying vec2 v_TexCoord;

    void main()
    {
        gl_FragColor = texture2D(u_Sampler, v_TexCoord);
    }`;

var gl = document.getElementById("renderCanvas").getContext("webgl");

var vShader = gl.createShader(gl.VERTEX_SHADER);
gl.shaderSource(vShader, vertexShaderSource);
gl.compileShader(vShader);

var fShader = gl.createShader(gl.FRAGMENT_SHADER);
gl.shaderSource(fShader, fragmentShaderSource);
gl.compileShader(fShader);

var program = gl.createProgram();
gl.attachShader(program, vShader);
gl.attachShader(program, fShader);
gl.linkProgram(program);
gl.useProgram(program);

var verticesAndTexCoords = new Float32Array([
    -0.5, 0.5, 0.0, 1.0,    // (x, y), (u, v)
    -0.5, -0.5, 0.0, 0.0,
    0.5, 0.5, 1.0, 1.0,
    0.5, -0.5, 1.0, 0.0
]);

var vbo = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, vbo);
gl.bufferData(gl.ARRAY_BUFFER, verticesAndTexCoords, gl.STATIC_DRAW);

var FSIZE = verticesAndTexCoords.BYTES_PER_ELEMENT;

var a_Position = gl.getAttribLocation(program, "a_Position");
gl.vertexAttribPointer(a_Position, 2, gl.FLOAT, false, 4 * FSIZE, 0);
gl.enableVertexAttribArray(a_Position);

var a_TexCoord = gl.getAttribLocation(program, "a_TexCoord");
gl.vertexAttribPointer(a_TexCoord, 2, gl.FLOAT, false, 4 * FSIZE, 2 * FSIZE);
gl.enableVertexAttribArray(a_TexCoord);

var image = new Image();

image.onload = function()
{
    gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, 1);
    gl.activeTexture(gl.TEXTURE0);

    var texture = gl.createTexture();
    gl.bindTexture(gl.TEXTURE_2D, texture);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
    gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGB, gl.RGB, gl.UNSIGNED_BYTE, image);

    var u_Sampler = gl.getUniformLocation(program, "u_Sampler");
    gl.uniform1i(u_Sampler, 0);

    var modelMatrix = mat4.create();
    mat4.translate(modelMatrix, modelMatrix, vec3.fromValues(0, 0.5, 0));
    mat4.rotateZ(modelMatrix, modelMatrix, 20.0 * Math.PI / 180.0);
    mat4.scale(modelMatrix, modelMatrix, vec3.fromValues(0.5 * 4.0, 0.5, 1));

    var u_ModelMatrix = gl.getUniformLocation(program, "u_ModelMatrix");
    gl.uniformMatrix4fv(u_ModelMatrix, false, modelMatrix);

    gl.clearColor(0.898, 0.984, 0.905, 1.0);
    gl.clear(gl.COLOR_BUFFER_BIT);

    gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
}
image.crossOrigin = "";
image.src = "https://dl.dropboxusercontent.com/s/zssokio89fl5dr5/cyberforum.png";