tor-browser

The Tor Browser
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test_hidden_alpha.html (4055B)

      1 <!DOCTYPE HTML>
      2 <title>WebGL test: Hidden alpha on no-alpha contexts</title>
      3 <script src='/tests/SimpleTest/SimpleTest.js'></script>
      4 <link rel='stylesheet' href='/tests/SimpleTest/test.css'>
      5 <script src='driver-info.js'></script>
      6 <script src='webgl-util.js'></script>
      7 <body>
      8 <script id='vs' type='x-shader/x-vertex'>
      9  attribute vec2 aPosCoord;
     10 
     11  void main(void) {
     12    gl_Position = vec4(aPosCoord, 0.0, 1.0);
     13  }
     14 </script>
     15 
     16 <script id='fs' type='x-shader/x-fragment'>
     17  precision mediump float;
     18 
     19  void main(void) {
     20    gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
     21  }
     22 </script>
     23 <canvas id='canvas' style='border: none;' width='100' height='100'></canvas>
     24 <script>
     25 
     26 var posCoords_arr = new Float32Array(2 * 4);
     27 var posCoords_buff = null;
     28 function DrawQuad(gl, prog, x0, y0, x1, y1) {
     29  gl.useProgram(prog);
     30 
     31  if (!posCoords_buff) {
     32    posCoords_buff = gl.createBuffer();
     33  }
     34  gl.bindBuffer(gl.ARRAY_BUFFER, posCoords_buff);
     35  posCoords_arr[0] = x0;
     36  posCoords_arr[1] = y0;
     37 
     38  posCoords_arr[2] = x1;
     39  posCoords_arr[3] = y0;
     40 
     41  posCoords_arr[4] = x0;
     42  posCoords_arr[5] = y1;
     43 
     44  posCoords_arr[6] = x1;
     45  posCoords_arr[7] = y1;
     46  gl.bufferData(gl.ARRAY_BUFFER, posCoords_arr, gl.STREAM_DRAW);
     47 
     48  gl.enableVertexAttribArray(prog.aPosCoord);
     49  gl.vertexAttribPointer(prog.aPosCoord, 2, gl.FLOAT, false, 0, 0);
     50 
     51  gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
     52 }
     53 
     54 function DrawSquare(gl, prog, size) {
     55  DrawQuad(gl, prog, -size, -size, size, size);
     56 }
     57 
     58 function Reset(gl) {
     59  gl.canvas.width += 1;
     60  gl.canvas.width -= 1;
     61 }
     62 
     63 function ReadCenterPixel(gl) {
     64  var w = gl.drawingbufferWidth;
     65  var h = gl.drawingbufferHeight;
     66  var ret = new Uint8Array(4);
     67  gl.readPixels(w/2, h/2, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, ret);
     68  return ret;
     69 }
     70 
     71 function Test(gl, prog) {
     72  gl.enable(gl.BLEND);
     73  gl.blendFunc(gl.ZERO, gl.DST_ALPHA);
     74 
     75  var iColor = 64;
     76  var fColor = iColor / 255.0;
     77 
     78  //////////////////
     79 
     80  ok(true, 'clear(R,G,B,0)');
     81 
     82  Reset(gl);
     83 
     84  gl.clearColor(fColor, fColor, fColor, 0.0);
     85  gl.clear(gl.COLOR_BUFFER_BIT);
     86 
     87  var dataURL_pre = gl.canvas.toDataURL();
     88  //console.log('Before blending: ' + dataURL_pre);
     89 
     90  DrawSquare(gl, prog, 0.7);
     91 
     92  var pixel = ReadCenterPixel(gl);
     93  ok(pixel[0] == iColor &&
     94     pixel[1] == iColor &&
     95     pixel[2] == iColor, 'Color should be the same.');
     96  ok(pixel[3] == 255, 'No-alpha should always readback as 1.0 alpha.');
     97 
     98  var dataURL_post = gl.canvas.toDataURL();
     99  //console.log('After blending: ' + dataURL_post);
    100  ok(dataURL_post == dataURL_pre,
    101     'toDataURL should be unchanged after blending.');
    102 
    103  //////////////////
    104 
    105  ok(true, 'mask(R,G,B,0), clear(R,G,B,1)');
    106 
    107  Reset(gl);
    108 
    109  gl.colorMask(true, true, true, false);
    110  gl.clearColor(fColor, fColor, fColor, 1.0);
    111  gl.clear(gl.COLOR_BUFFER_BIT);
    112  gl.colorMask(true, true, true, true);
    113 
    114  dataURL_pre = gl.canvas.toDataURL();
    115  //console.log('Before blending: ' + dataURL_pre);
    116 
    117  DrawSquare(gl, prog, 0.7);
    118 
    119  var pixel = ReadCenterPixel(gl);
    120  ok(pixel[0] == iColor &&
    121     pixel[1] == iColor &&
    122     pixel[2] == iColor, 'Color should be the same.');
    123  ok(pixel[3] == 255, 'No-alpha should always readback as 1.0 alpha.');
    124  ok(gl.getError() == 0, 'Should have no errors.');
    125 
    126  dataURL_post = gl.canvas.toDataURL();
    127  //console.log('After blending: ' + dataURL_post);
    128  ok(dataURL_post == dataURL_pre,
    129     'toDataURL should be unchanged after blending.');
    130 
    131  ok(true, 'Test complete.');
    132  SimpleTest.finish();
    133 }
    134 
    135 (function(){
    136  var canvas = document.getElementById('canvas');
    137  var attribs = {
    138    alpha: false,
    139    antialias: false,
    140    premultipliedAlpha: false,
    141  };
    142  var gl = canvas.getContext('experimental-webgl', attribs);
    143  ok(gl, 'WebGL should work.');
    144  ok(gl.getParameter(gl.ALPHA_BITS) == 0, 'Shouldn\'t have alpha bits.');
    145 
    146  var prog = WebGLUtil.createProgramByIds(gl, 'vs', 'fs');
    147  ok(prog, 'Program should link.');
    148  prog.aPosCoord = gl.getAttribLocation(prog, 'aPosCoord');
    149 
    150  SimpleTest.waitForExplicitFinish();
    151  SimpleTest.requestFlakyTimeout("untriaged");
    152  setTimeout(function(){ Test(gl, prog); }, 500);
    153 })();
    154 
    155 </script>
    156 </body>