third_party/WebKit/LayoutTests/fast/canvas/webgl/viewport-unchanged-upon-resize.html

   1 <html>
   2 <head>
   3 <script src="../../../resources/js-test.js"></script>
   4 <script src="resources/webgl-test.js"></script>
   5 <script id="vshader" type="x-shader/x-vertex">
   6 attribute vec3 g_Position;
   7
   8 void main()
   9 {
  10     gl_Position = vec4(g_Position.x, g_Position.y, g_Position.z, 1.0);
  11 }
  12 </script>
  13
  14 <script id="fshader" type="x-shader/x-fragment">
  15 void main()
  16 {
  17     gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
  18 }
  19 </script>
  20
  21 </head>
  22 <body>
  23 <canvas id="example" width="4px" height="4px"></canvas>
  24 <div id="description"></div>
  25 <div id="console"></div>
  26 <script>
  27 description('Verifies that GL viewport does not change when canvas is resized');
  28
  29 var gl = initWebGL("example", "vshader", "fshader", [ "g_Position" ], [ 0, 0, 1, 1 ], 1);
  30
  31 var vertices = new Float32Array([
  32      1.0,  1.0, 0.0,
  33     -1.0,  1.0, 0.0,
  34     -1.0, -1.0, 0.0,
  35      1.0,  1.0, 0.0,
  36     -1.0, -1.0, 0.0,
  37      1.0, -1.0, 0.0]);
  38 var vbo = gl.createBuffer();
  39 gl.bindBuffer(gl.ARRAY_BUFFER, vbo);
  40 gl.bufferData(gl.ARRAY_BUFFER, vertices, gl.STATIC_DRAW);
  41
  42 gl.enableVertexAttribArray(0);
  43 gl.vertexAttribPointer(0, 3, gl.FLOAT, false, 0, 0);
  44
  45 // Clear and set up
  46 gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
  47 gl.useProgram(gl.program);
  48 // Draw the triangle pair to the frame buffer
  49 gl.drawArrays(gl.TRIANGLES, 0, 6);
  50
  51 // Ensure that the frame buffer is red at the sampled pixel
  52 var buf = new Uint8Array(1 * 1 * 4);
  53 gl.readPixels(2, 2, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, buf);
  54 var passed = true;
  55 if (buf[0] != 255 ||
  56     buf[1] != 0 ||
  57     buf[2] != 0 ||
  58     buf[3] != 255) {
  59   testFailed("Pixel at (2, 2) should have been (255, 0, 0, 255), " +
  60              "was (" + buf[0] + ", " + buf[1] + ", " + buf[2] + ", " + buf[3] + ")");
  61   passed = false;
  62 }
  63
  64 if (passed) {
  65   // Now resize the canvas
  66   var canvas = document.getElementById("example");
  67   canvas.width = 8;
  68   canvas.height = 8;
  69   // Do another render
  70   gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
  71   gl.drawArrays(gl.TRIANGLES, 0, 6);
  72   // This time, because we did not change the viewport, it should
  73   // still be (0, 0, 4, 4), so only the lower-left quadrant should
  74   // have been filled.
  75   var buf = new Uint8Array(1 * 1 * 4);
  76   gl.readPixels(6, 6, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, buf);
  77   var passed = true;
  78   if (buf[0] != 0 ||
  79       buf[1] != 0 ||
  80       buf[2] != 255 ||
  81       buf[3] != 255) {
  82     testFailed("Pixel at (6, 6) should have been (0, 0, 255, 255), " +
  83                "was (" + buf[0] + ", " + buf[1] + ", " + buf[2] + ", " + buf[3] + ")");
  84     passed = false;
  85   }
  86 }
  87
  88 if (passed)
  89     testPassed("Viewport correctly did not change size during canvas resize");
  90 </script>
  91 </body>
  92 </html>