dom/canvas/test/webgl-conf/checkout/extra/lots-of-polys-example.html

   1 <!--
   2 Copyright (c) 2019 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
   7 <!DOCTYPE html>
   8 <html>
   9 <head>
  10 <meta charset="utf-8">
  11 <title>WebGL Lots of polygons example.</title>
  12 <link rel="stylesheet" href="../resources/js-test-style.css"/>
  13 <script src="../js/js-test-pre.js"></script>
  14 <script src="../js/webgl-test-utils.js"> </script>
  15 </head>
  16 <body>
  17 <canvas id="example" width="1024" height="1024" style="width: 40px; height: 40px;">
  18 </canvas>
  19 <div id="description"></div>
  20 <div id="console"></div>
  21 <script>
  22 "use strict";
  23 window.onload = init;
  24 debug("Tests a WebGL program that draws a bunch of large polygons");
  25
  26 function init() {
  27   if (confirm(
  28       "After clicking OK your machine may become unresponsive or crash.")) {
  29     main();
  30   } else {
  31     debug("cancelled");
  32   }
  33 }
  34
  35 function main() {
  36   var wtu = WebGLTestUtils;
  37   var canvas = document.getElementById("example");
  38   canvas.addEventListener("webglcontextlost", function(e) { e.preventDefault(); }, false);
  39   canvas.addEventListener("webglcontextrestored", function(e) { }, false);
  40
  41   var gl = wtu.create3DContext(canvas);
  42   var program = wtu.setupTexturedQuad(gl);
  43
  44   assertMsg(gl.getError() == gl.NO_ERROR, "Should be no errors from setup.");
  45
  46   var tex = gl.createTexture();
  47   gl.enable(gl.BLEND);
  48   gl.disable(gl.DEPTH_TEST);
  49
  50   wtu.fillTexture(gl, tex, 4096, 4096, [0, 192, 128, 255], 0);
  51   wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after creating texture");
  52
  53   gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
  54   gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
  55   gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
  56   gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
  57   wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after setting texture params");
  58
  59   var loc = gl.getUniformLocation(program, "tex");
  60   wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after getting tex locations");
  61   gl.uniform1i(loc, 0);
  62   wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after setting tex uniform");
  63
  64   var numQuads = 100000;
  65   var indexBuf = new ArrayBuffer(numQuads * 6);
  66   var indices = new Uint8Array(indexBuf);
  67   for (var ii = 0; ii < numQuads; ++ii) {
  68     var offset = ii * 6;
  69     indices[offset + 0] = 0;
  70     indices[offset + 1] = 1;
  71     indices[offset + 2] = 2;
  72     indices[offset + 3] = 3;
  73     indices[offset + 4] = 4;
  74     indices[offset + 5] = 5;
  75   }
  76   var indexBuffer = gl.createBuffer();
  77   gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indexBuffer);
  78   gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, indices, gl.STATIC_DRAW);
  79   wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after creating index buffer");
  80   gl.drawElements(gl.TRIANGLES, numQuads * 6, gl.UNSIGNED_BYTE, 0);
  81   wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after drawing");
  82
  83   var successfullyParsed = true;
  84 }
  85 </script>
  86 </body>
  87 </html>
  88
  89