<!--
Copyright (c) 2019 The Khronos Group Inc.
Use of this source code is governed by an MIT-style license that can be
found in the LICENSE.txt file.
-->

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<link rel="stylesheet" href="../../resources/js-test-style.css"/>
<script src="../../js/js-test-pre.js"></script>
<script src="../../js/webgl-test-utils.js"></script>
<style>
.pattern {
  white-space: nowrap;
  display: inline-block;
}
canvas {
  width:10px;
  height:10px;
}
.square {
  display:inline-block;
  width:10px;
  height:10px;
  background-color:red;
}
</style>
<script>
"use strict";
var wtu = WebGLTestUtils;
function checkResult(ctx1, ctx2, preserve) {
  var imgData1 = ctx1.getImageData(0,0,1,1);
  var imgData2 = ctx2.getImageData(0,0,1,1);
  var correct1 = [255,0,0,255];
  var correct2 = preserve ? [255,0,0,255] : [0,0,0,255];
  var ok1 = true;
  var ok2 = true;
  for (var p = 0; p < 4; ++p) {
    if (imgData1.data[p] != correct1[p])
      ok1 = false;
    if (imgData2.data[p] != correct2[p])
      ok2 = false;
  }
  if (ok1 && ok2)
    testPassed('Rendered ok with preserveDrawingBuffer ' + preserve +'.');
  else
    testFailed('Did not render ok with preserveDrawingBuffer ' + preserve + '.');
  if (preserve) {
    finishTest()
  } else {
    runTest(true);
  }
}

function runTest(preserve) {
  var c1 = document.getElementById('c' + (preserve * 3 + 1));
  var c2 = document.getElementById('c' + (preserve * 3 + 2));
  var c3 = document.getElementById('c' + (preserve * 3 + 3));
  var ctx1 = c1.getContext('2d');
  var ctx2 = c2.getContext('2d');
  var gl = wtu.create3DContext(c3, { alpha:false, preserveDrawingBuffer:preserve });
  if (!gl) {
    testFailed("context does not exist");
    if (preserve) {
      finishTest()
    } else {
      runTest(true);
    }
    return;
  }
  gl.clearColor(1, 0, 0, 1);
  gl.clear(gl.COLOR_BUFFER_BIT);
  ctx1.drawImage(c3, 0, 0);
  wtu.waitForComposite(function() {
    ctx2.drawImage(c3, 0, 0);
    checkResult(ctx1, ctx2, preserve);
  });
}
</script>
</head>
<body>
<div class="pattern">
  <canvas id='c1'></canvas>
  <canvas id='c2'></canvas>
  <canvas id='c3'></canvas>
</div>
<span>should look like</span>
<div class="pattern">
  <div class='square'></div>
  <div class='square' style='background-color:black'></div>
  <div class='square'></div>
</div>
<hr />
<div class="pattern">
  <canvas id='c4'></canvas>
  <canvas id='c5'></canvas>
  <canvas id='c6'></canvas>
</div>
<span>should look like</span>
<div class="pattern">
  <div class='square'></div>
  <div class='square'></div>
  <div class='square'></div>
</div>
<div id="description"></div>
<div id="console"></div>
<script>
"use strict";
description('Verify that preserveDrawingBuffer attribute is honored.');
runTest(false);
var successfullyParsed = true;
shouldBeTrue("successfullyParsed");
</script>
</body>
</html>
