<!--
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: Check that state is not lost by compositing</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="testbed" width="16" height="16" style="width:50px; height:50px"></canvas>
<div id="description"></div>
<div id="console"></div>
<script>
"use strict";
description();
var wtu = WebGLTestUtils;

function runTest()
{
  var gl = wtu.create3DContext('testbed', { antialias: false });
  if (!gl) {
    testFailed('could not create context');
    return;
  }

  var program = wtu.setupTexturedQuad(gl);
  var tex = gl.createTexture();
  var fb = gl.createFramebuffer();

  var step1 = function() {
    wtu.fillTexture(gl, tex, 1, 1, [0, 255, 0, 255]);
    wtu.clearAndDrawUnitQuad(gl);
    wtu.checkCanvas(gl, [0, 255, 0, 255], "drawing with texture should be green");
  };

  var step2 = function() {
    wtu.clearAndDrawUnitQuad(gl);
    wtu.checkCanvas(gl, [0, 255, 0, 255], "drawing with texture after composite without rebinding should be green");

    // Clear background to red
    gl.clearColor(1, 0, 0, 1);
    gl.clear(gl.COLOR_BUFFER_BIT);

    // Bind framebuffer with green texture.
    gl.bindFramebuffer(gl.FRAMEBUFFER, fb);
    gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, tex, 0);
    wtu.checkCanvasRect(gl, 0, 0, 1, 1, [0, 255, 0, 255], "reading from fbo with attached texture should be green");
  };

  var step3 = function() {
    // Should still have fb bound and reading should be green
    wtu.checkCanvasRect(gl, 0, 0, 1, 1, [0, 255, 0, 255], "reading from fbo after composite without rebinding should be green");
  };

  var steps = [
    step1,
    step2,
    step3,
  ];

  var stepIndex = 0;
  var runNextStep = function() {
    steps[stepIndex++]();
    if (stepIndex == steps.length) {
      wtu.glErrorShouldBe(gl, gl.NO_ERROR, "there should be no errors");
      finishTest();
      return;
    }
    wtu.waitForComposite(runNextStep);
  };
  runNextStep();
}

runTest();
var successfullyParsed = true;
</script>
</body>
</html>

