<!--
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.
-->

<!-- author: Bill Baxter (wbaxter at google.com) -->

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>ANGLE WebGL Shader Conditionals Repro</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="repro" style="border: none;" width="256" height="256"></canvas>
<div id="description"></div>
<div id="console"></div>

<script id="shader-vs" type="x-shader/x-vertex">
attribute vec2 pos;
varying mediump float varA;
void main(void) {
  varA = 0.;
  gl_Position = vec4(pos, 0.0, 1.0);
}
</script>

<script id="shader-fs" type="x-shader/x-fragment">
precision mediump float;
varying float varA;
void main(void) {
  if (varA < -1. || (varA < -1. && varA > 1.)) {
    discard;
  }
  gl_FragColor = vec4(0, 1, 0, 1) + 2. * varA * 2.;
}
</script>

<script id="shader-fs-mutable" type="x-shader/x-fragment">
precision mediump float;
varying float varA;
void main(void) {
  float b = varA;
  if (varA < (b -= 1.) || (varA < b && varA > (b += 2.))) {
    discard;
  }
  gl_FragColor = vec4(0, 1, 0, 1) + 2. * varA * 2.;
}
</script>
<script id="shader-fs-unfolded" type="x-shader/x-fragment">
precision mediump float;
varying float varA;
void main(void) {
  bool s1 = varA < -1.;
  if (!s1) {
    bool s2 = varA < -1.;
    if (s2) {
      s2 = varA > 1.;
    }
    s1 = s2;
  }
  if (s1) {
    discard;
  }
  gl_FragColor = vec4(0, 1, 0, 1) + 2. * varA * 2.;
}
</script>
<script>
"use strict";

description();
debug("");
debug("If things are working correctly, then there will be a green square.");
debug("Otherwise it will be a black void.");
debug("This is a repro for an issue seen on the D3D9 ANGLE implementation of WebGL on Chrome in a shader with a conditional discard, where the conditional is of the form (a || (b && c)).");

var wtu = WebGLTestUtils;
var canvas = document.getElementById("repro");
var gl = wtu.create3DContext(canvas);
if (!gl) {
  testFailed("context does not exist");
} else {
  gl.clearColor(0.0, 0.0, 0.0, 1.0);
  wtu.setupUnitQuad(gl);

  debug("");
  debug("Testing shader with conditional discard");
  gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
  var program = wtu.setupProgram(gl, ["shader-vs", "shader-fs"], ["pos"], undefined, true);
  wtu.drawUnitQuad(gl);
  wtu.checkCanvasRect(gl, 128, 128, 128, 128, [ 0, 255, 0, 255 ], "should be green", 1);

  debug("");
  debug("Testing conditional discard with side-effects in conditions");
  gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
  var programMutable = wtu.setupProgram(gl, ["shader-vs", "shader-fs-mutable"], ["pos"], undefined, true);
  wtu.drawUnitQuad(gl);
  wtu.checkCanvasRect(gl, 128, 128, 128, 128, [ 0, 255, 0, 255 ], "should be green", 1);

  debug("");
  debug("Testing conditional discard with unfolded condition logic");
  gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
  var programMutable = wtu.setupProgram(gl, ["shader-vs", "shader-fs-unfolded"], ["pos"], undefined, true);
  wtu.drawUnitQuad(gl);
  wtu.checkCanvasRect(gl, 128, 128, 128, 128, [ 0, 255, 0, 255 ], "should be green", 1);
}

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