<!--
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 GLSL built in variables Conformance Test</title>
<link rel="stylesheet" href="../../../resources/js-test-style.css"/>
<link rel="stylesheet" href="../../../resources/glsl-feature-tests.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="example" width="2" height="2"> </canvas>
<script id="vshader" type="x-shader/x-vertex">
attribute vec4 a_position;
void main()
{
    gl_Position = a_position;
}
</script>
<script id="vshaderCheck" type="x-shader/x-vertex">
attribute vec4 a_position;
varying vec4 v_color;
void main()
{
    gl_Position = a_position;
    v_color = (gl_$(name) == $(max)) ? vec4(0,1,0,1) : vec4(1,0,0,1);
}
</script>
<script id="fshader" type="x-shader/x-fragment">
precision mediump float;
varying vec4 v_color;
void main()
{
    gl_FragColor = v_color;
}
</script>
<script id="fshaderCheck" type="x-shader/x-fragment">
precision mediump float;
void main()
{
    gl_FragColor = (gl_$(name) == $(max)) ? vec4(0,1,0,1) : vec4(1,0,0,1);
}
</script>
<script>
"use strict";
description();
var wtu = WebGLTestUtils;
var gl = wtu.create3DContext("example");
var contextVersion = wtu.getDefault3DContextVersion();

var variables = [
  { name: 'MaxVertexAttribs',             min:   8, },
  { name: 'MaxVertexUniformVectors',      min: 128, },
  { name: 'MaxVaryingVectors',            min:   8, },
  { name: 'MaxVertexTextureImageUnits',   min:   0, },
  { name: 'MaxCombinedTextureImageUnits', min:   8, },
  { name: 'MaxTextureImageUnits',         min:   8, },
  { name: 'MaxFragmentUniformVectors',    min:  16, },
];

if (contextVersion <= 1) {
  variables.push({ name: 'MaxDrawBuffers', min: 1, max: 1});
} else {
  variables.push({ name: 'MaxDrawBuffers', min: 1, });
}

var toUnderscore = function(str) {
  return str.replace(/([a-z])([A-Z])/g, function (g) { return g[0] + "_" + g[1].toUpperCase() }).toUpperCase();
};

var shaderPairs = [
   [wtu.getScript("vshader"), wtu.getScript("fshaderCheck")],
   [wtu.getScript("vshaderCheck"), wtu.getScript("fshader")],
];

wtu.setupUnitQuad(gl);

variables.forEach(function(variable) {
  debug("");
  debug("Testing gl_" + variable.name);
  if (!variable.max) {
    variable.max = gl.getParameter(gl[toUnderscore(variable.name)]);
    expectTrue(variable.max >= variable.min, "gl.getParameter(gl." + toUnderscore(variable.name) + ") >= " + variable.min);
  }
  shaderPairs.forEach(function(pair) {
    var shaders = [wtu.replaceParams(pair[0], variable), wtu.replaceParams(pair[1], variable)];
    var program = wtu.setupProgram(gl, shaders, ["a_position"], undefined, true);
    wtu.clearAndDrawUnitQuad(gl);
    wtu.checkCanvas(gl, [0, 255, 0, 255], "should be green");
  });
});

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

