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Copyright (c) 2019 The Khronos Group Inc.
Use of this source code is governed by an MIT-style license that can be
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<html>
<head>
<meta charset="utf-8">
<title>Test clearBufferfv with alpha:false canvas</title>
<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>
</head>
<body>
<div id="description"></div>
<div id="console"></div>
<canvas id="canvas" width="20" height="20"> </canvas>
<script>
"use strict";
description("This tests the operation of clearBufferfv with the back buffer of an alpha:false canvas.");

function verifyOnePixel(readFormat, readType, arrayType, expectedColor) {
  var buffer = new arrayType(4);
  gl.readPixels(0, 0, 1, 1, readFormat, readType, buffer);
  if (buffer[0] == expectedColor[0] &&
      buffer[1] == expectedColor[1] &&
      buffer[2] == expectedColor[2] &&
      buffer[3] == expectedColor[3]) {
    testPassed("clearBufferfv set the color buffer to the correct value");
  } else {
    testFailed("clearBufferfv failed to work. Expected: " + expectedColor + ", got: " + buffer);
  }
}

function testClearBuffer(func, format, arrayType, readFormat, readType, readArrayType) {
  debug("");
  debug("Testing " + func);

  var srcData = new arrayType([0, 1, 0, 0]);
  gl[func](gl.COLOR, 0, srcData);
  wtu.glErrorShouldBe(gl, gl.NO_ERROR, "clearBuffer with no srcOffset should succeed");
  // Back buffer has no alpha channel
  verifyOnePixel(readFormat, readType, Uint8Array, [0, 255, 0, 255]);
}

var wtu = WebGLTestUtils;
var canvas = document.getElementById("canvas");
var gl = wtu.create3DContext(canvas, { alpha:false }, 2);
if (!gl) {
  testFailed("context does not exist");
} else {
  testPassed("context exists");

  var testCases = [
    {
      func: "clearBufferfv", format: gl.RGBA, arrayType: Float32Array,
      readFormat: gl.RGBA, readType: gl.UNSIGNED_BYTE, readArrayType: Uint8Array,
    },
  ];

  for (var tt = 0; tt < testCases.length; ++tt) {
    var test = testCases[tt];
    if (test.extension && !gl.getExtension(test.extension))
      continue;
    testClearBuffer(test.func, test.format, test.arrayType,
                    test.readFormat, test.readType, test.readArrayType);
  }
}

debug("");
wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no error");
var successfullyParsed = true;

</script>
<script src="../../js/js-test-post.js"></script>

</body>
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