third_party/WebKit/LayoutTests/fast/canvas/webgl/array-bounds-clamping.html

   1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   2   "http://www.w3.org/TR/html4/loose.dtd">
   3 <html>
   4 <head>
   5 <title>WebGL array bounds clamping conformance test.</title>
   6 <script src="../../../resources/js-test.js"></script>
   7 <script src="resources/webgl-test.js"> </script>
   8 </head>
   9 <body>
  10 <canvas id="example" width="40" height="40" style="width: 40px; height: 40px;"></canvas>
  11 <div id="description"></div>
  12 <div id="console"></div>
  13 <script id="vshader" type="x-shader/x-vertex">
  14 #ifdef GL_ES
  15 precision highp float;
  16 #endif
  17 attribute vec4 vPosition;
  18 attribute float index;
  19 uniform float shades[8];
  20 varying vec4 texColor;
  21 void main()
  22 {
  23     gl_Position = vPosition;
  24     texColor = vec4(shades[int(index)], 0, 0, 1.0);
  25 }
  26 </script>
  27
  28 <script id="fshader" type="x-shader/x-fragment">
  29 #ifdef GL_ES
  30 precision highp float;
  31 #endif
  32 varying vec4 texColor;
  33 void main()
  34 {
  35     gl_FragColor = texColor;
  36 }
  37 </script>
  38
  39 <script>
  40 function init()
  41 {
  42     if (window.initNonKhronosFramework)
  43         window.initNonKhronosFramework(false);
  44
  45     debug("Checks that array access in a shader can not read out of bounds");
  46     debug("");
  47
  48     gl = initWebGL("example", "vshader", "fshader", [ "vPosition", "index" ],
  49                    [ 1, 1, 1, 1 ], 1);
  50
  51     gl.disable(gl.DEPTH_TEST);
  52     gl.disable(gl.BLEND);
  53
  54     var vertexObject = gl.createBuffer();
  55     gl.bindBuffer(gl.ARRAY_BUFFER, vertexObject);
  56     gl.bufferData(gl.ARRAY_BUFFER,
  57                   new Float32Array([ -1,1,0, 1,1,0, -1,-1,0,
  58                                      -1,-1,0, 1,1,0, 1,-1,0 ]),
  59                   gl.STATIC_DRAW);
  60     gl.enableVertexAttribArray(0);
  61     gl.vertexAttribPointer(0, 3, gl.FLOAT, false, 0, 0);
  62
  63     var vertexObject = gl.createBuffer();
  64     gl.bindBuffer(gl.ARRAY_BUFFER, vertexObject);
  65     gl.bufferData(gl.ARRAY_BUFFER,
  66                   // Create an array that exercises well outside the
  67                   // limits on each side, near the limits, and the
  68                   // exact limits.
  69                   // This should be clamped to [0, 0, 0, 7, 7, 7]
  70                   new Float32Array([ -123456789, -1, 0, 7, 8, 123456789]),
  71                   gl.STATIC_DRAW);
  72     gl.enableVertexAttribArray(1);
  73     gl.vertexAttribPointer(1, 1, gl.FLOAT, false, 0, 0);
  74
  75     var loc = gl.getUniformLocation(gl.program, "shades");
  76     gl.uniform1fv(loc, [0.25, 0.5, 0, 0, 0, 0, 0.75, 1]);
  77
  78     checkRedValue(0, 38, 64, "Top left corner should clamp to index 0");
  79     checkRedValue(37, 38, 64, "Inside top right corner should clamp to index 0");
  80     checkRedValue(0, 1, 64, "Inside bottom left corner should clamp to index 0");
  81
  82     checkRedValue(38, 0, 255, "Bottom right corner should clamp to index 7");
  83     checkRedValue(3, 1, 255, "Outside bottom left corner should clamp to index 7");
  84     checkRedValue(38, 37, 255, "Outside top right corner should clamp to index 7");
  85
  86     function checkRedValue(x, y, value, msg) {
  87         gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
  88         gl.drawArrays(gl.TRIANGLES, 0, 6);
  89         gl.flush();
  90         var buf = new Uint8Array(4);
  91         gl.readPixels(x, y, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, buf);
  92         if (buf[0] != value || buf[1] != 0 || buf[2] != 0 || buf[3] != 255) {
  93             debug('expected: rgb(' + value + ', 0, 0, 255) was rgb(' + buf[0] + ', ' + buf[1] + ', ' + buf[2] + ', ' + buf[3] + ')');
  94             testFailed(msg);
  95             return;
  96         }
  97         testPassed(msg);
  98     }
  99 }
 100
 101 init();
 102 </script>
 103 </body>
 104 </html>
 105