<!--
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 Disabled Vertex Attrib Test</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 id="vshader" type="x-shader/x-vertex">
attribute vec4 a_position;
attribute vec4 a_color;
varying vec4 v_color;
bool isCorrectColor(vec4 v) {
  return v.x == 0.0 && v.y == 0.0 && v.z == 0.0 && v.w == 1.0;
}
void main() {
  gl_Position = a_position;
  v_color = isCorrectColor(a_color) ? 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>
"use strict";
var wtu = WebGLTestUtils;
description();

var gl = wtu.create3DContext("example");

var numVertexAttribs = gl.getParameter(gl.MAX_VERTEX_ATTRIBS);
for (var ii = 0; ii < numVertexAttribs; ++ii) {
  var colorLocation = (ii + 1) % numVertexAttribs;
  var positionLocation = colorLocation ? 0 : 1;

  if (positionLocation != 0) {
    // We need to create a new 3d context for testing attrib 0
    // since we've already effected attrib 0 on other tests.
    gl = wtu.create3DContext();
  }

  debug("testing attrib: " + colorLocation);
  var program = wtu.setupProgram(
      gl,
      ['vshader', 'fshader'],
      ['a_position', 'a_color'],
      [positionLocation, colorLocation]);
  var gridRes = 1;
  wtu.setupIndexedQuad(gl, gridRes, positionLocation);
  wtu.clearAndDrawIndexedQuad(gl, gridRes);
  wtu.checkCanvas(gl, [0, 255, 0, 255], "should be green");
}
wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors");

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

</body>
</html>

