
<!DOCTYPE html>
<html>
  <head>
    <title>Rendering Test</title>
    <script src="../../../resources/js-test.js"></script>
    <script src="resources/webgl-test.js"> </script>
</head>
<body>
<canvas id="example" width="50" height="50">
There is supposed to be an example drawing here, but it's not important.
</canvas>
<div id="description"></div>
<div id="console"></div>
    <script id="vshader" type="x-shader/x-vertex">
        attribute vec4 vPosition;
        void main()
        {
            gl_Position = vPosition;
        }
    </script>

    <script id="fshader" type="x-shader/x-fragment">
        void main()
        {
            gl_FragColor = vec4(1.0,0.0,0.0,1.0);
        }
    </script>

    <script>
        function fail(x,y, buf, shouldBe)
        {
            var i = (y*50+x) * 4;
            var reason = "pixel at ("+x+","+y+") is ("+buf[i]+","+buf[i+1]+","+buf[i+2]+","+buf[i+3]+"), should be "+shouldBe;
            testFailed(reason);
        }

        function pass()
        {
            testPassed("drawing is correct");
        }

        function init()
        {
            if (window.initNonKhronosFramework) {
                window.initNonKhronosFramework(false);
            }

            gl = initWebGL("example", "vshader", "fshader", [ "vPosition"], [ 0, 0, 0, 1 ], 1);

            var vertexObject = gl.createBuffer();
            gl.bindBuffer(gl.ARRAY_BUFFER, vertexObject);
            gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([ 0,0.5,0, -0.5,-0.5,0, 0.5,-0.5,0 ]), gl.STATIC_DRAW);
            gl.enableVertexAttribArray(0);
            gl.vertexAttribPointer(0, 3, gl.FLOAT, false, 0, 0);

            gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
            gl.drawArrays(gl.TRIANGLES, 0, 3);

            var buf = new Uint8Array(50 * 50 * 4);
            gl.readPixels(0, 0, 50, 50, gl.RGBA, gl.UNSIGNED_BYTE, buf);

            // Test several locations
            // First line should be all black
            for (var i = 0; i < 50; ++i)
                if (buf[i*4] != 0 || buf[i*4+1] != 0 || buf[i*4+2] != 0 || buf[i*4+3] != 255) {
                    fail(i, 0, buf, "(0,0,0,255)");
                    return;
                }

            // Line 15 should be red for at least 10 red pixels starting 20 pixels in
            var offset = (15*50+20) * 4;
            for (var i = 0; i < 10; ++i)
                if (buf[offset+i*4] != 255 || buf[offset+i*4+1] != 0 || buf[offset+i*4+2] != 0 || buf[offset+i*4+3] != 255) {
                    fail(20 + i, 15, buf, "(255,0,0,255)");
                    return;
                }
            // Last line should be all black
            offset = (49*50) * 4;
            for (var i = 0; i < 50; ++i)
                if (buf[offset+i*4] != 0 || buf[offset+i*4+1] != 0 || buf[offset+i*4+2] != 0 || buf[offset+i*4+3] != 255) {
                    fail(i, 49, buf, "(0,0,0,255)");
                    return;
                }

            pass();
       }

       init();
    </script>
</body>
</html>