<!--
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 Scissor Test</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>
<style>
canvas {
    border: 1px solid #000;
    width: 64px;
    height: 64px;
}
</style>
</head>
<body>
<canvas id="canvas1" width="16" height="16"> </canvas>
<canvas id="canvas2" width="16" height="16"> </canvas>
<div id="description"></div>
<div id="console"></div>
<script>
"use strict";
description("Check if glScissor setting works.");

var wtu = WebGLTestUtils;

function test(canvas, attribs) {
  var gl = wtu.create3DContext(canvas, attribs);

  function test(func) {
    gl.disable(gl.SCISSOR_TEST);
    gl.clearColor(0,0,0,0);
    gl.clear(gl.COLOR_BUFFER_BIT);
    gl.enable(gl.SCISSOR_TEST);

    var size = 16;
    for (var ii = 0; ii < size; ++ii) {
      // clear a portion of the WebGL drawing buffer
      gl.scissor(ii, ii, 1, 1);
      func();
    }

    for (var ii = 0; ii < size; ++ii) {
      wtu.checkCanvasRect(gl, 0, ii, ii, 1, [0, 0, 0, 0], "should be black");
      wtu.checkCanvasRect(gl, ii, ii, 1, 1, [0, 255, 0, 255], "should be green");
      wtu.checkCanvasRect(gl, ii + 1, ii, size - ii - 1, 1, [0, 0, 0, 0], "should be black");
    }
  }

  if (!gl) {
    testFailed("context does not exist");
  } else {
    testPassed("context exists");

    debug("");
    debug("test with clear");
    test(function() {
      gl.clearColor(0, 1, 0, 1);
      gl.clear(gl.COLOR_BUFFER_BIT);
    });

    wtu.setupColorQuad(gl);

    debug("");
    debug("test with draw");
    test(function() {
      wtu.drawFloatColorQuad(gl, [0, 1, 0, 1]);
    });

    wtu.glErrorShouldBe(gl, gl.NO_ERROR, "there should be no errors");
  }
}

debug("test antialias: false");
test(document.getElementById("canvas1"), {antialias: false});

debug("");
debug("test antialias: true");
test(document.getElementById("canvas2"), {antialias: true});

debug("");
var successfullyParsed = true;

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

</body>
</html>
