third_party/WebKit/LayoutTests/fast/canvas/webgl/read-pixels-pack-alignment.html

   1 <html>
   2 <head>
   3 <script src="../../../resources/js-test.js"></script>
   4 <script src="resources/webgl-test.js"></script>
   5 <script id="vshader" type="x-shader/x-vertex">
   6 attribute vec3 pos;
   7 attribute vec4 colorIn;
   8 varying vec4 color;
   9
  10 void main()
  11 {
  12     color = colorIn;
  13     gl_Position = vec4(pos.xyz, 1.0);
  14 }
  15 </script>
  16
  17 <script id="fshader" type="x-shader/x-fragment">
  18 #ifdef GL_ES
  19 precision mediump float;
  20 #endif
  21 varying vec4 color;
  22
  23 void main()
  24 {
  25     gl_FragColor = color;
  26 }
  27 </script>
  28 </head>
  29 <body>
  30 <canvas id="example" width="32px" height="32px"></canvas>
  31 <div id="description"></div>
  32 <div id="console"></div>
  33 <script>
  34 if (window.internals)
  35     window.internals.settings.setWebGLErrorsToConsoleEnabled(false);
  36
  37 // The below declarations need to be global for "shouldBe" to see them
  38 var gl = null;
  39 var array = null;
  40 var pixel = [ 0, 0, 0, 0 ];
  41 var expectedColor = [ 0, 0, 0, 0 ];
  42
  43 function calculatePixelBytes(format, type)
  44 {
  45     var size = 0;
  46     switch (format) {
  47     case gl.ALPHA:
  48         size = 1;
  49         break;
  50     case gl.RGB:
  51         size = 3;
  52         break;
  53     case gl.RGBA:
  54         size = 4;
  55         break;
  56     default:
  57         return -1;
  58     }
  59     switch (type) {
  60     case gl.UNSIGNED_BYTE:
  61         break;
  62     case gl.UNSIGNED_SHORT_5_6_5:
  63         if (format != gl.RGB)
  64             return -1;
  65         size = 2;
  66         break;
  67     case gl.UNSIGNED_SHORT_4_4_4_4:
  68     case gl.UNSIGNED_SHORT_5_5_5_1:
  69         if (format != gl.RGBA)
  70             return -1;
  71         size = 2;
  72         break;
  73     default:
  74         return -1;
  75     }
  76     return size;
  77 }
  78
  79 function calculatePaddingBytes(bytesPerPixel, packAlignment, width)
  80 {
  81     var padding = 0;
  82     switch (packAlignment) {
  83     case 1:
  84     case 2:
  85     case 4:
  86     case 8:
  87         padding = (bytesPerPixel * width) % packAlignment;
  88         if (padding > 0)
  89             padding = packAlignment - padding;
  90         break;
  91     default:
  92         return -1;
  93     }
  94     return padding;
  95 }
  96
  97 function packColor(format, type, r, g, b, a)
  98 {
  99     // FIXME: not sure if the color packing is correct for UNSIGNED_SHORT_*.
 100     var color = [ 0, 0, 0, 0 ];
 101     switch (type) {
 102     case gl.UNSIGNED_BYTE:
 103         switch (format) {
 104         case gl.ALPHA:
 105             color[0] = a;
 106             break;
 107         case gl.RGB:
 108             color[0] = r;
 109             color[1] = g;
 110             color[2] = b;
 111             break;
 112         case gl.RGBA:
 113             color[0] = r;
 114             color[1] = g;
 115             color[2] = b;
 116             color[3] = a;
 117             break;
 118         default:
 119             return null;
 120         }
 121         break;
 122     case gl.UNSIGNED_SHORT_5_6_5:
 123         if (format != gl.RGB)
 124             return null;
 125         r >>= 3;
 126         g >>= 2;
 127         b >>= 3;
 128         color[0] = (r << 11) + (g << 5) + b;
 129         break;
 130     case gl.UNSIGNED_SHORT_4_4_4_4:
 131         if (format != gl.RGBA)
 132             return null;
 133         r >>= 4;
 134         g >>= 4;
 135         b >>= 4;
 136         a >>= 4;
 137         color[0] = (r << 12) + (g << 8) + (b << 4) + a;
 138         break;
 139     case gl.UNSIGNED_SHORT_5_5_5_1:
 140         if (format != gl.RGBA)
 141             return null;
 142         r >>= 3;
 143         g >>= 3;
 144         b >>= 3;
 145         a >>= 7;
 146         color[0] = (r << 11) + (g << 6) + (b << 1) + a;
 147         break;
 148     Default:
 149         return null;
 150     }
 151     return color;
 152 }
 153
 154 function runTestIteration(format, type, packAlignment, width, height)
 155 {
 156     debug("Testing PACK_ALIGNMENT = " + packAlignment + ", width = " + width + ", height = " + height);
 157     gl.clearColor(1, 0.4, 0, 1);
 158     gl.clear(gl.COLOR_BUFFER_BIT);
 159     gl.pixelStorei(gl.PACK_ALIGNMENT, packAlignment);
 160     glErrorShouldBe(gl, gl.NO_ERROR);
 161     var bytesPerPixel = calculatePixelBytes(format, type);
 162     var padding = calculatePaddingBytes(bytesPerPixel, packAlignment, width);
 163     var size = bytesPerPixel * width * height + padding * (height - 1);
 164     var isShort = false;
 165     switch (type) {
 166     case gl.UNSIGNED_SHORT_5_6_5:
 167     case gl.UNSIGNED_SHORT_4_4_4_4:
 168     case gl.UNSIGNED_SHORT_5_5_5_1:
 169         isShort = true;
 170     }
 171     if (isShort)
 172         size /= 2;
 173     if (size < 0)
 174         size = 0;
 175     if (type == gl.UNSIGNED_BYTE)
 176         array = new Uint8Array(size);
 177     else
 178         array = new Uint16Array(size);
 179     gl.readPixels(0, 0, width, height, format, type, array);
 180     if (width < 0 || height < 0) {
 181         glErrorShouldBe(gl, gl.INVALID_VALUE);
 182         return;
 183     } else {
 184         glErrorShouldBe(gl, gl.NO_ERROR);
 185         if (!array.length)
 186             return;
 187     }
 188     // Check the last pixel of the last row.
 189     var bytesPerRow = width * bytesPerPixel + padding;
 190     var pos = bytesPerRow * (height - 1) + (width - 1) * bytesPerPixel;
 191     var numComponents = bytesPerPixel;
 192     if (isShort) {
 193         pos /= 2;
 194         numComponents /= 2;
 195     }
 196     for (var i = 0; i < numComponents; ++i)
 197         pixel[i] = array[pos + i];
 198     for (var i = numComponents; i < 4; ++i)
 199         pixel[i] = 0;
 200     expectedColor = packColor(format, type, 255, 102, 0, 255);
 201     shouldBeNonNull(expectedColor);
 202     shouldBe("pixel", "expectedColor");
 203 }
 204
 205 description('Verify readPixels() works fine with various PACK_ALIGNMENT values.');
 206
 207 shouldBeNonNull("gl = initWebGL('example', 'vshader', 'fshader', [ 'pos', 'colorIn' ], [ 0, 0, 0, 1 ], 1)");
 208 gl.disable(gl.BLEND);
 209
 210 debug("Testing format = RGBA and type = UNSIGNED_BYTE");
 211 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 1, 1, 2);
 212 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 2, 1, 2);
 213 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 4, 1, 2);
 214 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 8, 1, 2);
 215 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 4, 2, 2);
 216 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 8, 2, 2);
 217 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 4, 3, 2);
 218 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 8, 3, 2);
 219 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 4, 4, 2);
 220 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 8, 4, 2);
 221 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 8, 5, 1);
 222 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 4, 5, 2);
 223 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 8, 5, 2);
 224 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 8, 6, 2);
 225 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 8, 7, 2);
 226 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 8, 8, 2);
 227 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 1, 0, 0);
 228 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 2, 0, 0);
 229 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 4, 0, 0);
 230 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 8, 0, 0);
 231 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 1, -1, 1);
 232 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 2, 1, -1);
 233 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 4, 0, -1);
 234 runTestIteration(gl.RGBA, gl.UNSIGNED_BYTE, 8, -1, -1);
 235 </script>
 236 </body>
 237 </html>