dom/canvas/test/webgl-conf/checkout/conformance/programs/use-program-crash-with-discard-in-fragment-shader.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>WebGL Program Conformance Tests</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 </head>
  16 <body>
  17 <div id="description"></div>
  18 <div id="console"></div>
  19 <canvas id="canvas" width="2" height="2"> </canvas>
  20 <script id="vertexShader" language="x-shader/x-vertex">
  21 attribute vec4 ATTR0;
  22 void main()
  23 {
  24   gl_Position = ATTR0;
  25 }
  26 </script>
  27 <script id="fragmentShader" language="x-shader/x-fragment">
  28 precision mediump float;
  29 void main()
  30 {
  31   float _Intensity = exp2(gl_FragCoord.w);
  32   if (_Intensity < 0.5) {
  33     discard;
  34   }
  35   gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
  36 }
  37 </script>
  38 <script>
  39 "use strict";
  40 description('Regression test for crash in Mac OS AMD OpenGL driver related to use of discard in fragment shader.<br><br>More specifically, triggering the crash seems to require examination of gl_FragCoord.w, use of exp2, and a call to discard in the fragment shader. Thanks to Sheheryar Zakaria and Michael Braithwaite at Turbulenz for the original test case.<br><a href="https://bugs.webkit.org/show_bug.cgi?id=73932">WebKit bug 73932</a><br>');
  41
  42 debug("");
  43
  44 var wtu = WebGLTestUtils;
  45 var gl = wtu.create3DContext("canvas");
  46 if (!gl) {
  47   testFailed("context does not exist");
  48 } else {
  49   testPassed("context exists");
  50 }
  51
  52 debug("");
  53
  54 var program = wtu.loadProgramFromScript(gl, 'vertexShader', 'fragmentShader');
  55 if (program) {
  56   testPassed("Program linked successfully");
  57 } else {
  58   testFailed("Program failed to link");
  59 }
  60
  61 // Crash occurs here on affected machines
  62 gl.useProgram(program);
  63
  64 // In some browsers, such as Chrome, the above crash only causes a
  65 // lost context event to be dispatched, and not synchronously. To verify
  66 // that everything worked, clear and read back the frame buffer.
  67 gl.clearColor(1.0, 0.0, 0.0, 1.0);
  68 gl.clear(gl.COLOR_BUFFER_BIT);
  69 wtu.checkCanvasRect(gl, 0, 0, 1, 1, [255, 0, 0, 255],
  70     "Color should be red");
  71
  72 var successfullyParsed = true;
  73 </script>
  74 <script src="../../js/js-test-post.js"></script>
  75
  76 </body>
  77 </html>