<!DOCTYPE HTML>
<title>WebGL test: bug 958723</title>
<script src="/tests/SimpleTest/SimpleTest.js"></script>
<link rel="stylesheet" href="/tests/SimpleTest/test.css">
<script src="driver-info.js"></script>
<script src="webgl-util.js"></script>
<body>
<script>

function TestAttribs(attribs) {
  ok(true, 'Testing attribs: ' + JSON.stringify(attribs));
  var canvas = document.createElement('canvas');
  var gl = canvas.getContext('experimental-webgl', attribs);
  ok(gl, 'No tested attribs should result in failure to create a context');
  if (!gl)
    return;

  var actual = gl.getContextAttributes();

  ok(actual.alpha == attribs.alpha,
     'Resulting `alpha` should match request.');
  ok(actual.premultipliedAlpha == attribs.premultipliedAlpha,
     'Resulting `premultipliedAlpha` should match request.');
  ok(actual.preserveDrawingBuffer == attribs.preserveDrawingBuffer,
     'Resulting `preserveDrawingBuffer` should match request.');

  // "The depth, stencil and antialias attributes, when set to true, are
  // requests, not requirements."
  if (!attribs.antialias) {
    ok(!actual.antialias, 'No `antialias` if not requested.');
  }
  if (!attribs.depth) {
    ok(!actual.depth, 'No `depth` if not requested.');
  }
  if (!attribs.stencil) {
    ok(!actual.stencil, 'No `stencil` if not requested.');
  }

  var hasAlpha = !!gl.getParameter(gl.ALPHA_BITS);
  var hasDepth = !!gl.getParameter(gl.DEPTH_BITS);
  var hasStencil = !!gl.getParameter(gl.STENCIL_BITS);
  var hasAntialias = !!gl.getParameter(gl.SAMPLES);

  ok(hasAlpha == actual.alpha, 'Bits should match `alpha` attrib.');
  ok(hasAntialias == actual.antialias, 'Bits should match `antialias` attrib.');
  ok(hasDepth == actual.depth, 'Bits should match `depth` attrib.');
  ok(hasStencil == actual.stencil, 'Bits should match `stencil` attrib.');
}

function CloneAttribs(attribs) {
  return {
    alpha: attribs.alpha,
    antialias: attribs.antialias,
    depth: attribs.depth,
    premultipliedAlpha: attribs.premultipliedAlpha,
    preserveDrawingBuffer: attribs.preserveDrawingBuffer,
    stencil: attribs.stencil,
  };
}

function SplitForAttrib(list, attrib) {
  var ret = [];

  for (var i in list) {
    var cur = list[i];
    if (cur[attrib])
      throw 'Attrib is already true.';

    var clone = CloneAttribs(cur);
    clone[attrib] = true;

    ret.push(cur);
    ret.push(clone);
  }

  return ret;
}

function GenAttribList() {
  var base = {
    alpha: false,
    antialias: false,
    depth: false,
    premultipliedAlpha: false,
    preserveDrawingBuffer: false,
    stencil: false,
  };
  var list = [base];
  list = SplitForAttrib(list, 'alpha');
  list = SplitForAttrib(list, 'antialias');
  list = SplitForAttrib(list, 'depth');
  list = SplitForAttrib(list, 'premultipliedAlpha');
  list = SplitForAttrib(list, 'preserveDrawingBuffer');
  list = SplitForAttrib(list, 'stencil');

  if (list.length != 1<<6)
    throw 'Attribs list length wrong: ' + list.length;

  return list;
}

var list = GenAttribList();
for (var i in list) {
  var attribs = list[i];
  TestAttribs(attribs);
}

ok(true, 'Test complete.');

</script>

