dom/canvas/test/webgl-conf/checkout/extra/slow-shader-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 Slow Shader 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 id="slow" type="text/something-not-javascript">
  22 precision mediump float;
  23 uniform sampler2D tex;
  24 varying vec2 texCoord;
  25 void main() {
  26   gl_FragColor = texture2D(tex, texture2D(tex, texture2D(tex, texCoord).xy).xy);
  27 }
  28 </script>
  29 <script>
  30 "use strict";
  31 window.onload = main;
  32
  33 debug("Tests drawing a very slow shader.");
  34 var wtu = WebGLTestUtils;
  35 var canvas = document.getElementById("example");
  36 canvas.addEventListener("webglcontextlost", function(e) { e.preventDefault(); }, false);
  37 canvas.addEventListener("webglcontextrestored", function(e) { }, false);
  38 var gl = wtu.create3DContext(canvas);
  39 var maxTexSize = gl.getParameter(gl.MAX_TEXTURE_SIZE);
  40 var texSize = Math.min(maxTexSize, 4096);
  41 debug("Max Texture size: " + maxTexSize);
  42 debug("Texture size: " + texSize);
  43 var shaderSource =
  44     document.getElementById("slow").text.replace(/\$size/g, texSize + ".0");
  45 wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after getting a context");
  46 var program = wtu.setupProgram(
  47     gl,
  48     [wtu.simpleTextureVertexShader, shaderSource],
  49     ['vPosition', 'texCoord0'],
  50     [0, 1]);
  51 wtu.setupUnitQuad(gl, 0, 1);
  52 wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after program setup");
  53 var tex = gl.createTexture();
  54 gl.enable(gl.BLEND);
  55 gl.disable(gl.DEPTH_TEST);
  56
  57 wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after creating texture");
  58 debug("preparing...");
  59 var numBytes = texSize * texSize * 4;
  60 var pixelBuf = new ArrayBuffer(numBytes);
  61 var pixels = new Uint8Array(pixelBuf);
  62 for (var ii = 0; ii < numBytes; ++ii) {
  63   pixels[ii] = Math.random() * 255;
  64 }
  65 gl.bindTexture(gl.TEXTURE_2D, tex);
  66 gl.texImage2D(
  67       gl.TEXTURE_2D, 0, gl.RGBA, texSize, texSize, 0,
  68       gl.RGBA, gl.UNSIGNED_BYTE, pixels);
  69 wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after texture setup");
  70
  71 gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
  72 gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
  73 gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT);
  74 gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT);
  75 wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after texture param setting");
  76
  77 var loc = gl.getUniformLocation(program, "tex");
  78 wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after getting tex location");
  79 gl.uniform1i(loc, 0);
  80 wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after setting tex uniform");
  81
  82 var numQuads = 1000;
  83 var indexBuf = new ArrayBuffer(numQuads * 6);
  84 var indices = new Uint8Array(indexBuf);
  85 for (var ii = 0; ii < numQuads; ++ii) {
  86   var offset = ii * 6;
  87   indices[offset + 0] = 0;
  88   indices[offset + 1] = 1;
  89   indices[offset + 2] = 2;
  90   indices[offset + 3] = 3;
  91   indices[offset + 4] = 4;
  92   indices[offset + 5] = 5;
  93 }
  94 var indexBuffer = gl.createBuffer();
  95 gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indexBuffer);
  96 gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, indices, gl.STATIC_DRAW);
  97 wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after setting up indices");
  98
  99 function main () {
 100   if (confirm(
 101       "After clicking OK your machine may become unresponsive or crash.")) {
 102     gl.drawElements(gl.TRIANGLES, numQuads * 6, gl.UNSIGNED_BYTE, 0);
 103     wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after drawing");
 104   } else {
 105     debug("cancelled");
 106   }
 107 }
 108
 109 var successfullyParsed = true;
 110 </script>
 111 </body>
 112 </html>