<!--
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>Verifies than GL framebuffer bindings do not change by toDataURL()</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>
<canvas id="example" width="50" height="50"></canvas>
<div id="description"></div>
<div id="console"></div>
<script>
"use strict";
description("Verifies than GL framebuffer bindings do not change by toDataURL()");

var wtu = WebGLTestUtils;
function test() {
  var glCanvas = document.getElementById("example");
  var gl = wtu.create3DContext(glCanvas, {preserveDrawingBuffer: true, premultipliedAlpha: true});

  if (!gl) {
    testFailed("context does not exist");
    return;
  }

  var program = wtu.setupColorQuad(gl);

  // Clear backbuffer in red.
  gl.clearColor(1.0, 0.0, 0.0, 1.0);
  gl.clear(gl.COLOR_BUFFER_BIT);
  wtu.checkCanvas(gl, [255, 0, 0, 255], "should be red");

  var fbo = gl.createFramebuffer();
  var tex = gl.createTexture();
  gl.bindTexture(gl.TEXTURE_2D, tex);
  gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 50, 50, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
  gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
  gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, tex, 0);
  if (gl.checkFramebufferStatus(gl.FRAMEBUFFER) != gl.FRAMEBUFFER_COMPLETE) {
    return;
  }

  // Clear the FBO in green.
  gl.clearColor(0.0, 1.0, 0.0, 1.0);
  gl.clear(gl.COLOR_BUFFER_BIT);

  // backbuffer is still in red.
  gl.bindFramebuffer(gl.FRAMEBUFFER, null);
  wtu.checkCanvas(gl, [255, 0, 0, 255], "should be red");
  gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);

  // toDataURL() calls must not bind backbuffer.
  glCanvas.toDataURL();
  // Calling twice caused a bug due to wrong cache impl; crbug.com/445848
  glCanvas.toDataURL();
  // It must applies to the FBO, not backbuffer.
  gl.clear(gl.COLOR_BUFFER_BIT);

  // backbuffer must be in red, not green.
  gl.bindFramebuffer(gl.FRAMEBUFFER, null);
  wtu.checkCanvas(gl, [255, 0, 0, 255], "should be red");
}
test();

var successfullyParsed = true;
</script>
<script src="../../js/js-test-post.js"></script>
</body>
</html>
