dom/canvas/test/webgl-conf/checkout/conformance2/wasm/readpixels-4gb-wasm-memory.html

   1 <!--
   2 Copyright (c) 2023 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 <!DOCTYPE html>
   7 <html>
   8 <head>
   9 <meta charset="utf-8">
  10 <title>gl.readPixels() test to Wasm Memory 4GB in size.</title>
  11 <link rel="stylesheet" href="../../resources/js-test-style.css"/>
  12 <script src="../../js/js-test-pre.js"></script>
  13 <script src="../../js/webgl-test-utils.js"> </script>
  14 </head>
  15 <body>
  16 <canvas id="canvas" width="2" height="2" style="width: 40px; height: 40px;"></canvas>
  17 <div id="description"></div>
  18 <div id="console"></div>
  19 <script>
  20 "use strict";
  21 description(document.title);
  22 debug("Tests that gl.readPixels() can be called on WebAssembly Memory of 4GB in size.");
  23 debug("");
  24 let wtu = WebGLTestUtils;
  25 let gl = wtu.create3DContext("canvas", undefined, 2);
  26
  27 const PAGE = 65536;
  28 const SIZE = 4*1024*1024*1024 - PAGE; // when uint32_t size is max, we can only reach one page short of full 4GB
  29 let view = new Uint8Array(new WebAssembly.Memory({ initial: SIZE/PAGE }).buffer);
  30
  31 // Clear the canvas to a specific color
  32 const expectedColor = [42, 84, 128, 255];
  33 gl.clearColor(expectedColor[0]/255.0, expectedColor[1]/255.0, expectedColor[2]/255.0, expectedColor[3]/255.0);
  34 gl.clear(gl.COLOR_BUFFER_BIT);
  35
  36 // Test that gl.readPixels() can be called with a high offset to Memory
  37 const offset = SIZE - 4;
  38 view.set([0,0,0,0], offset); // For good measure, clear data at offset before reading
  39 gl.readPixels(0, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, view, offset);
  40 wtu.glErrorShouldBe(gl, gl.NO_ERROR);
  41 let obtainedColor = view.subarray(offset, offset+4);
  42 shouldBe('obtainedColor[0]', 'expectedColor[0]');
  43 shouldBe('obtainedColor[1]', 'expectedColor[1]');
  44 shouldBe('obtainedColor[2]', 'expectedColor[2]');
  45 shouldBe('obtainedColor[3]', 'expectedColor[3]');
  46 var successfullyParsed = true;
  47 </script>
  48 <script src="../../js/js-test-post.js"></script>
  49 </body>
  50 </html>