<!--
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">
<title>WebGL Behavior After Alert and Read Pixels Test</title>
<link rel="stylesheet" href="../resources/js-test-style.css"/>
<script src="../../devtools/src/debug/webgl-debug.js"></script>
<script src="../js/js-test-pre.js"></script>
<script src="../js/webgl-test-utils.js"></script>
</head>
<body>
<canvas id="canvas" width="100" height="100"> </canvas>
<div id="description">Verify WebGL behavior after an alert and then a readPixels()</div>
<div id="console"></div>
<script>
"use strict";

function checkPixels(buf, width, height, thresh) {
  for (var yy = 0; yy < height; ++yy) {
    for (var xx = 0; xx < width; ++xx) {
      var offset = (yy * width + xx) * 4;
      if (Math.abs(buf[offset] - 255) > thresh ||
          Math.abs(buf[offset + 1] - 0) > thresh ||
          Math.abs(buf[offset + 2] - 0) > thresh) {
        testFailed("Checking pixels");
        return false;
      }
    }
  }
  testPassed("Checking pixels");
  return true;
}

var wtu = WebGLTestUtils;
var gl = wtu.create3DContext("canvas");
gl.clearColor(1, 0, 0, 1);
gl.clear(gl.COLOR_BUFFER_BIT);
wtu.glErrorShouldBe(gl, gl.NO_ERROR, "setup should succeed");

wtu.checkCanvas(gl, [255, 0, 0, 255], undefined, 3);

alert("Click me to continue");

wtu.glErrorShouldBe(gl, gl.NO_ERROR, "setup should succeed");
wtu.checkCanvas(gl, [255, 0, 0, 255], undefined, 3);

alert("Click me to continue");

gl.clearColor(1, 0, 0, 1);
gl.clear(gl.COLOR_BUFFER_BIT);
wtu.checkCanvas(gl, [255, 0, 0, 255], undefined, 3);

debug("");
var successfullyParsed = true;
</script>
<script src="../js/js-test-post.js"></script>

</body>
</html>
