<!--
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 Canvas Conformance Tests</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" style="width: 50px; height: 50px;"> </canvas>
<canvas id="canvas2d" width="40" height="40"> </canvas>
<script>
"use strict";

description("This test ensures WebGL implementations interact correctly with the canvas tag.");

debug("");
debug("Canvas.getContext");

var err;
var wtu = WebGLTestUtils;
var canvas = document.getElementById("canvas");
var canvas2d = document.getElementById("canvas2d");
var ctx2d = canvas2d.getContext("2d");
var gl = wtu.create3DContext(canvas);
if (!gl) {
  testFailed("context does not exist");
  finishTest();
} else {
  testPassed("context exists");

  debug("");
  debug("Checking canvas and WebGL interaction");

  // Check that a canvas with no width or height is 300x150 pixels
  shouldBe('canvas.width', '300');
  shouldBe('canvas.height', '150');

  // Check get a 4 value gl parameter as a csv string.
  var getValue4v = function(name) {
    var v = gl.getParameter(name);
    var result = '' +
        v[0] + ',' +
        v[1] + ',' +
        v[2] + ',' +
        v[3];
    return result;
  }

  var getViewport = function() {
    return getValue4v(gl.VIEWPORT);
  }

  var getClearColor = function() {
    return getValue4v(gl.COLOR_CLEAR_VALUE);
  }

  var isAboutEqual = function(a, b) {
    return Math.abs(a - b) < 0.01;
  }

  var isAboutEqualInt = function(a, b) {
    return Math.abs(a - b) < 3;
  }

  var checkCanvasContentIs = function(r3d,g3d,b3d,a3d) {
    var r2d;
    var g2d;
    var b2d;
    var a2d;

    var checkPixel = function(x, y, r3d,g3d,b3d,a3d) {
      var offset = (y * 40 + x) * 4;
      r2d = imgData.data[offset];
      g2d = imgData.data[offset + 1];
      b2d = imgData.data[offset + 2];
      a2d = imgData.data[offset + 3];
      var res = isAboutEqualInt(r2d, r3d) &&
                isAboutEqualInt(g2d, g3d) &&
                isAboutEqualInt(b2d, b3d) &&
                isAboutEqualInt(a2d, a3d);
      if (!res) {
        bufferedLogToConsole('at ' + x + ', ' + y + " (offset " + offset + ") = " + r2d + ", " + g2d + ", " + b2d + ", " + a2d);
      }
      return res;
    }

    var checkPixels = function(r3d,g3d,b3d,a3d) {
      return checkPixel(0, 0, r3d, g3d, b3d, a3d) &&
             checkPixel(0, 39, r3d, g3d, b3d, a3d) &&
             checkPixel(39, 0, r3d, g3d, b3d, a3d) &&
             checkPixel(39, 39, r3d, g3d, b3d, a3d) &&
             checkPixel(0, 0, r3d, g3d, b3d, a3d);
    };

    // Set to just take the color from the 3d canvas
    ctx2d.globalCompositeOperation = 'copy';

    // fill 2d canvas with orange
    ctx2d.fillStyle = "rgb(255,192,128)";
    ctx2d.fillRect (0, 0, 40, 40);

    // get the image data
    var imgData = ctx2d.getImageData(0, 0, 40, 40);

    // check it got cleared.
    if (!checkPixels(255, 192, 128, 255)) {
      testFailed("unable to fill 2d context.");
      return;
    }

    // draw 3d canvas on top.
    ctx2d.drawImage(canvas, 0,0, 40, 40);

    // get the image data
    var imgData = ctx2d.getImageData(0, 0, 40, 40);

    // Check it's the expected color.
    if (!checkPixels(r3d, g3d, b3d, a3d)) {
     testFailed("pixels are " + r2d + "," + g2d + "," + b2d + "," + a2d +
                " expected " + r3d + "," + g3d + "," + b3d + "," + a3d);
    } else {
      testPassed("pixels are " + r3d + "," + g3d + "," + b3d + "," + a3d);
    }
  }

  checkCanvasContentIs(0, 0, 0, 0);
  shouldBe('getViewport()', '"0,0,300,150"');

  // Change the display size of the canvas and check
  // the viewport size does not change.
  debug("");
  debug("change display size of canvas and see that viewport does not change");
  canvas.style.width = "100px";
  canvas.style.height = "25px";
  var intervalId;
  intervalId = window.setInterval(function() {
    if (canvas.clientWidth == 100 &&
        canvas.clientHeight == 25) {
      window.clearInterval(intervalId);
      shouldBe('getViewport()', '"0,0,300,150"');
      shouldBe('canvas.width', '300');
      shouldBe('canvas.height', '150');

      // Change the actual size of the canvas
      // Check that the viewport does not change.
      // Check that the clear color does not change.
      // Check that the color mask does not change.
      debug("");
      debug("change the actual size of the canvas and see that the viewport does not change");
      gl.clearColor(0.25, 0.5, 0.75, 1);
      gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
      checkCanvasContentIs(64, 128, 192, 255);
      gl.colorMask(0,0,0,0);
      wtu.glErrorShouldBe(gl, gl.NO_ERROR, "No GL errors before resizing the canvas");
      canvas.width = 400;
      canvas.height = 10;
      err = gl.getError();
      // Some implementations might lost the context when resizing
      if (err != gl.CONTEXT_LOST_WEBGL) {
        shouldBe("err", "gl.NO_ERROR");
        var v = gl.getParameter(gl.COLOR_CLEAR_VALUE);
        assertMsg(isAboutEqual(v[0], 0.25) &&
                  isAboutEqual(v[1], 0.5) &&
                  isAboutEqual(v[2], 0.75) &&
                  isAboutEqual(v[3], 1),
                  "gl.clearColor should not change after canvas resize");
        v = gl.getParameter(gl.COLOR_WRITEMASK);
        assertMsg(isAboutEqual(v[0], 0) &&
                  isAboutEqual(v[1], 0) &&
                  isAboutEqual(v[2], 0) &&
                  isAboutEqual(v[3], 0),
                  "gl.colorMask should not change after canvas resize");
        shouldBe('getViewport()', '"0,0,300,150"');
        checkCanvasContentIs(0, 0, 0, 0);
      }

      debug("");
      finishTest();
    }
   }, 1000/30);
}
</script>

</body>
</html>
