third_party/WebKit/LayoutTests/fast/canvas/webgl/renderbuffer-initialization.html

   1 <html>
   2 <head>
   3 <script src="../../../resources/js-test.js"></script>
   4 <script src="resources/webgl-test.js"></script>
   5 <script>
   6 function runTest(gl, width, height)
   7 {
   8
   9     debug('Test whether the WebGL internal buffers have been initialized to 0.');
  10     var totalBytes = width * height * 4;
  11     var buf = new Uint8Array(totalBytes);
  12     gl.readPixels(0, 0, width, height, gl.RGBA, gl.UNSIGNED_BYTE, buf);
  13     if (gl.getError() != gl.NO_ERROR) {
  14         testFailed('GL error detected after readPixels().');
  15         return false;
  16     }
  17     for (var i = 0; i < totalBytes; ++i) {
  18         if (buf[i] != 0) {
  19             testFailed('WebGL internal buffers are dirty.');
  20             return false;
  21         }
  22     }
  23     testPassed('Buffers have been initialized to 0.');
  24
  25     debug('Test whether user created buffers have been initialized to 0.');
  26     var fbo = gl.createFramebuffer();
  27     gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
  28     var colorbuffer = gl.createRenderbuffer();
  29     gl.bindRenderbuffer(gl.RENDERBUFFER, colorbuffer);
  30     gl.renderbufferStorage(gl.RENDERBUFFER, gl.RGBA4, width, height);
  31     if (gl.getError() != gl.NO_ERROR) {
  32         testFailed('GL error detected after renderbufferStorage(internalformat = RGBA4).');
  33         return false;
  34     }
  35     gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.RENDERBUFFER, colorbuffer);
  36     if (gl.checkFramebufferStatus(gl.FRAMEBUFFER) != gl.FRAMEBUFFER_COMPLETE) {
  37         testFailed('Framebuffer incomplete.');
  38         return false;
  39     }
  40     gl.readPixels(0, 0, width, height, gl.RGBA, gl.UNSIGNED_BYTE, buf);
  41     if (gl.getError() != gl.NO_ERROR) {
  42         testFailed('GL error detected after readPixels().');
  43         return false;
  44     }
  45     for (var i = 0; i < totalBytes; ++i) {
  46         if (buf[i] != 0) {
  47             testFailed('User created buffers are dirty.');
  48             return false;
  49         }
  50     }
  51
  52     testPassed('Buffers have been initialized to 0.');
  53     return true;
  54 }
  55 </script>
  56 </head>
  57 <body>
  58 <canvas id="testbed" width="400px" height="400px"></canvas>
  59 <div id="description"></div>
  60 <div id="console"></div>
  61 <script>
  62
  63 description('Verify renderbuffers are initialized to 0 before being read in WebGL');
  64
  65 var canvas = document.getElementById("testbed");
  66 var gl = canvas.getContext("webgl");
  67 if (gl) {
  68     runTest(gl, canvas.width, canvas.height);
  69
  70     // Testing that canvas resizing will clear the buffers with 0 instead of the current clear values.
  71     gl.clearColor(1, 0, 0, 1);
  72     canvas.width += 1;
  73     canvas.height += 1;
  74     runTest(gl, canvas.width, canvas.height);
  75
  76     // Testing buffer clearing won't change the clear values.
  77     var clearColor = gl.getParameter(gl.COLOR_CLEAR_VALUE);
  78     shouldBe("clearColor", "[1, 0, 0, 1]");
  79 } else
  80     testFailed('canvas.getContext() failed');
  81 </script>
  82 </body>
  83 </html>