gecko/content/canvas/test/webgl-conformance/extra/out-of-bounds-uniform-array-access.html

<!--
Copyright (c) 2011 The Chromium Authors. All rights reserved.
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file.
 -->
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
  "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta charset="utf-8">
<title>WebGL ouf of bounds uniform array access.</title>
<link rel="stylesheet" href="../resources/js-test-style.css"/>
<script src="../resources/js-test-pre.js"></script>
<script src="../conformance/resources/webgl-test-utils.js"> </script>
</head>
<body style="background: #666;">
<div id="description"></div>
<div id="console"></div>
<div>elem mult: <span id="elemMultDisplay"></span></div>
<input type="range" id="elemMult" value="4" min="0" max="2048" style="width: 100%;"/>
<div>line width: <span id="lineWidthDisplay"></span></div>
<input type="range" id="lineWidth" value="512" min="0" max="2540" style="width: 100%;"/>
<canvas id="example" width="256" height="256" style="background: black;">
</canvas>
<script id="vshader" type="x-shader/x-vertex">
attribute vec4 vPosition;
varying vec4 v_color;
uniform float lineWidth;
uniform int elemMult;
uniform vec4 someArray[2];
void main()
{
    vec2 texcoord = vec2(vPosition.xy * 0.5 + vec2(0.5, 0.5));
    int index = int(texcoord.x + texcoord.y * lineWidth) * elemMult;
    v_color = someArray[index];
    gl_Position = vPosition;
}
</script>

<script id="fshader" type="x-shader/x-fragment">
precision mediump float;
varying vec4 v_color;
void main()
{
  gl_FragColor = v_color * vec4(1.0 / 256.0, 1.0 / 256.0, 1.0 / 256.0, 1.0 / 256.0) + vec4(0,0,0,0.5);
}
</script>
<script>
window.onload = main;
debug("Tests a WebGL program that accesses out of bounds uniform array elements");

function main() {
  var wtu = WebGLTestUtils;
  var gl = wtu.create3DContext("example");
  var program = wtu.setupProgram(
      gl,
      ['vshader', 'fshader'],
      ['vPosition'], [0]);
  var gridRes = 255;
  wtu.setupQuad(gl, gridRes, 0);
  var lineWidthLoc = gl.getUniformLocation(program, "lineWidth");
  var elemMultLoc = gl.getUniformLocation(program, "elemMult");
  assertMsg(gl.getError() == gl.NO_ERROR, "Should be no errors from setup.");

  var lineWidth = 512;
  var lineWidthElem = document.getElementById("lineWidth");
  var lineWidthDisplayElem = document.getElementById("lineWidthDisplay");

  lineWidthElem.value = lineWidth;

  lineWidthElem.addEventListener('change', function(event) {
      //console.log(event.target.value);
      lineWidth = event.target.value;
      draw();
    }, false);

  var elemMult = 4;
  var elemMultElem = document.getElementById("elemMult");
  var elemMultDisplayElem = document.getElementById("elemMultDisplay");

  elemMultElem.value = elemMult;

  elemMultElem.addEventListener('change', function(event) {
      //console.log(event.target.value);
      elemMult = event.target.value;
      draw();
    }, false);

  draw();

  function draw() {
    lineWidthDisplayElem.innerText = lineWidth;
    elemMultDisplayElem.innerText = elemMult;
    gl.uniform1f(lineWidthLoc, lineWidth);
    gl.uniform1i(elemMultLoc, elemMult);
    gl.drawElements(gl.TRIANGLES, gridRes * gridRes * 6, gl.UNSIGNED_SHORT, 0);
  }

  successfullyParsed = true;
}

</script>
</body>
</html>