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1 <canvas id="withoutPreserve" width="50" height="50"></canvas> | |
2 <canvas id="withPreserve" width="50" height="50"></canvas> | |
Justin Novosad
2017/01/11 21:40:04
You don't need these.
xlai (Olivia)
2017/01/12 20:04:47
Done.
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3 <script src="../../resources/testharness.js"></script> | |
4 <script src="../../resources/testharnessreport.js"></script> | |
5 <script> | |
6 | |
7 function getPixelsFromOffscreenWebgl(placeHolderCanvasId, preserveFlag) { | |
8 var canvas = document.getElementById(placeHolderCanvasId); | |
Justin Novosad
2017/01/11 21:40:04
Just do:
var canvas = document.createElement('canv
xlai (Olivia)
2017/01/12 20:04:47
Done.
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9 var offscreenCanvas = canvas.transferControlToOffscreen(); | |
10 var gl = offscreenCanvas.getContext("webgl", {preserveDrawingBuffer: preserveF lag}); | |
11 | |
12 // Draw some color on gl and commit | |
13 gl.clearColor(1, 0, 1, 1); | |
14 gl.clear(gl.COLOR_BUFFER_BIT); | |
15 gl.commit(); | |
16 | |
17 var pixels = new Uint8Array(50 * 50 * 4); | |
18 gl.readPixels(0, 0, 50, 50, gl.RGBA, gl.UNSIGNED_BYTE, pixels); | |
19 return pixels; | |
20 } | |
21 | |
22 test(function() { | |
23 var pixelsPreserve = getPixelsFromOffscreenWebgl("withPreserve", true); | |
24 assert_equals(pixelsPreserve[0], 255); | |
25 assert_equals(pixelsPreserve[1], 0); | |
26 assert_equals(pixelsPreserve[2], 255); | |
27 assert_equals(pixelsPreserve[3], 255); | |
28 }, "test if OffscreenCanvas.webgl retains context if preserveDrawingBuffer is tr ue."); | |
29 | |
30 test(function() { | |
31 var pixelsNoPreserve = getPixelsFromOffscreenWebgl("withoutPreserve", false); | |
32 assert_equals(pixelsNoPreserve[0], 0); | |
33 assert_equals(pixelsNoPreserve[1], 0); | |
34 assert_equals(pixelsNoPreserve[2], 0); | |
35 assert_equals(pixelsNoPreserve[3], 0); | |
36 }, "test if OffscreenCanvas.webgl loses context if presereDrawingbuffer is false ."); | |
37 </script> | |
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