dom/canvas/test/webgl-conf/checkout/conformance/renderbuffers/renderbuffer-initialization.html

   1 <!--
   2 Copyright (c) 2019 The Khronos Group Inc.
   3 Use of this source code is governed by an MIT-style license that can be
   4 found in the LICENSE.txt file.
   5 -->
   6
   7 <!DOCTYPE html>
   8 <html>
   9 <head>
  10 <meta charset="utf-8">
  11 <link rel="stylesheet" href="../../resources/js-test-style.css"/>
  12 <script src="../../js/js-test-pre.js"></script>
  13 <script src="../../js/webgl-test-utils.js"></script>
  14 </head>
  15 <body>
  16 <canvas id="testbed" width="400" height="400" style="width: 40px; height: 40px;"></canvas>
  17 <div id="description"></div>
  18 <div id="console"></div>
  19 <script>
  20 "use strict";
  21 var wtu = WebGLTestUtils;
  22 description('Verify renderbuffers are initialized to 0 before being read in WebGL');
  23
  24 var gl = wtu.create3DContext("testbed");
  25 if (!gl) {
  26     testFailed('canvas.getContext() failed');
  27 } else {
  28     // Set the clear color to green. It should never show up.
  29     gl.clearColor(0, 1, 0, 1);
  30
  31     runTest(gl, gl.canvas.width, gl.canvas.height, 0);
  32     runTest(gl, gl.canvas.width, gl.canvas.height, 1);
  33     runTest(gl, gl.canvas.width, gl.canvas.height, 0);
  34     runTest(gl, gl.canvas.width, gl.canvas.height, 1);
  35
  36     // Testing buffer clearing won't change the clear values.
  37     var clearColor = gl.getParameter(gl.COLOR_CLEAR_VALUE);
  38     shouldBe("clearColor", "[0, 1, 0, 1]");
  39     wtu.glErrorShouldBe(gl, gl.NO_ERROR, 'should be no errors');
  40 }
  41
  42 function runTest(gl, width, height, order)
  43 {
  44     wtu.checkCanvasRect(gl, 0, 0, width, height, [0,0,0,0],
  45                         "internal buffers have been initialized to 0");
  46
  47     // fill the back buffer so we know that reading below happens from
  48     // the renderbuffer.
  49     gl.clear(gl.COLOR_BUFFER_BIT);
  50
  51     var fbo = gl.createFramebuffer();
  52     gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
  53     var colorbuffer = gl.createRenderbuffer();
  54     gl.bindRenderbuffer(gl.RENDERBUFFER, colorbuffer);
  55     switch (order) {
  56       case 0:
  57         allocStorage(width, height);
  58         attachBuffer(colorbuffer);
  59         break;
  60       case 1:
  61         attachBuffer(colorbuffer);
  62         allocStorage(width, height);
  63         break;
  64     }
  65
  66     function allocStorage(width, height) {
  67       gl.renderbufferStorage(gl.RENDERBUFFER, gl.RGBA4, width, height);
  68       wtu.glErrorShouldBe(gl, gl.NO_ERROR, 'should be no error after renderbufferStorage(internalformat = RGBA4).');
  69     }
  70
  71     function attachBuffer(colorbuffer) {
  72       gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.RENDERBUFFER, colorbuffer);
  73     }
  74
  75     if (gl.checkFramebufferStatus(gl.FRAMEBUFFER) != gl.FRAMEBUFFER_COMPLETE) {
  76         testFailed('Framebuffer incomplete.');
  77         return;
  78     }
  79
  80     wtu.checkCanvasRect(gl, 0, 0, width, height, [0,0,0,0],
  81                         "user buffers have been initialized to 0");
  82
  83     gl.deleteFramebuffer(fbo);
  84     gl.deleteRenderbuffer(colorbuffer);
  85
  86     // this clear should not matter we are about to resize
  87     gl.clear(gl.COLOR_BUFFER_BIT);
  88
  89     gl.canvas.width += 1;
  90     gl.canvas.height += 1;
  91
  92     debug('');
  93 }
  94
  95 var successfullyParsed = true;
  96 </script>
  97 <script src="../../js/js-test-post.js"></script>
  98 </body>
  99 </html>