dom/canvas/test/webgl-conf/checkout/conformance/manual/canvas-no-clear-on-readpixels.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 <title>Check that the canvas is NOT recomposited after calling readPixels</title>
  12 <link rel="stylesheet" href="../../resources/js-test-style.css"/>
  13 <script src="../../js/js-test-pre.js"></script>
  14 <script src="../../js/webgl-test-utils.js"></script>
  15 <style>
  16 canvas {
  17     border: 1px solid black;
  18 }
  19 .correct {
  20     border: 1px solid black;
  21     background-color: #00ff00;
  22 }
  23 </style>
  24 </head>
  25 <body>
  26 <pre>
  27 This test must be run manually.
  28
  29 This test tests that a canvas is NOT cleared
  30 and recomposited after calling readPixels.
  31
  32 You should see a <span class="correct">green rectangle</span>
  33 with black a outline on success.
  34 </pre>
  35 <canvas id='c'></canvas>
  36 <div id="console"></div>
  37 <script>
  38 "use strict";
  39 var wtu = WebGLTestUtils;
  40 var c = document.getElementById("c");
  41 var gl = wtu.create3DContext(c);
  42 gl.clearColor(0,1,0,1);
  43 gl.clear(gl.COLOR_BUFFER_BIT);
  44 wtu.waitForComposite(function() {
  45   gl.readPixels(0, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, new Uint8Array(4));
  46   wtu.glErrorShouldBe(gl, gl.NO_ERROR, "no errors");
  47 });
  48 </script>
  49 </body>
  50 </html>