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<meta charset="utf-8">
<!--
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.
-->
<link rel="stylesheet" type="text/css" href="../unit.css" />
<script type="application/javascript" src="../unit.js"></script>
<script type="application/javascript" src="../util.js"></script>
<script type="application/javascript">

var verts = [0.0, 0.0, 0.0,   1.0, 0.0, 0.0,   0.0, 1.0, 0.0];
var normals = [0.0, 0.0, 1.0,   0.0, 0.0, 1.0,   0.0, 0.0, 1.0];
var texcoords = [0.0,0.0,  1.0,0.0,  0.0,1.0];
var indices = [0,1,2]

Tests.startUnit = function () {
  var canvas = document.getElementById('gl');
  var gl = wrapGLContext(getGLContext(canvas));
  var prog = new Shader(gl, 'vert', 'frag');
  prog.use();
  var sh = prog.shader.program;
  var v = gl.getAttribLocation(sh, 'Vertex');
  var n = gl.getAttribLocation(sh, 'Normal');
  var t = gl.getAttribLocation(sh, 'Tex');
  return [gl,prog,v,n,t];
}

Tests.setup = function(gl, prog, v,n,t) {
  assert(0 == gl.getError());
  return [gl, prog, v,n,t];
}
Tests.teardown = function(gl, prog, v,n,t) {
  gl.disableVertexAttribArray(v);
  gl.disableVertexAttribArray(n);
  gl.disableVertexAttribArray(t);
}

Tests.endUnit = function(gl, prog, v,n,t) {
  prog.destroy();
}

Tests.testDrawElementsVBO = function(gl, prog, v,n,t) {
    var vbo = new VBO(gl,
                       {size:3, data:Quad.vertices},
                       {elements:true, data:Quad.indices});
  vbo.draw(v);
  assert(gl.NO_ERROR == checkError(gl, "vbo.draw"));
  assertOk(function(){gl.drawElements(gl.TRIANGLES, 5, gl.UNSIGNED_SHORT, 1*2);});
  assertOk(function(){gl.drawElements(gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 0*2);});
  assertOk(function(){gl.drawElements(gl.TRIANGLES, 0, gl.UNSIGNED_SHORT, 2*1);});
  assertOk(function(){gl.drawElements(gl.TRIANGLES, 1, gl.UNSIGNED_SHORT, 5*2);});
  vbo.destroy();
  assert(gl.NO_ERROR == checkError(gl, "vbo.destroy"));
}

Tests.testDrawElementsVBOMulti = function(gl, prog, v,n,t) {
  // creates VBOs for the quad arrays, binds them with
  // vertexAttribPointer and calls drawElements
  var vbo = new VBO(gl,
                    {size:3, data:Quad.vertices},
                    {size:3, data:Quad.normals},
                    {size:2, data:Quad.texcoords},
                    {elements:true, data:Quad.indices});
  vbo.draw(v, n, t);
  assert(gl.NO_ERROR == checkError(gl, "vbo.draw"));
  assertOk(function(){gl.drawElements(gl.TRIANGLES, 5, gl.UNSIGNED_SHORT, 1*2);});
  assertOk(function(){gl.drawElements(gl.TRIANGLES, 0, gl.UNSIGNED_SHORT, 2*2);});
  assertOk(function(){gl.drawElements(gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 0*2);});
  assertOk(function(){gl.drawElements(gl.TRIANGLES, 1, gl.UNSIGNED_SHORT, 5*2);});
  assertGLError(gl, gl.INVALID_OPERATION, "count + offset out of range",
      function(){gl.drawElements(gl.TRIANGLES, 1, gl.UNSIGNED_SHORT, 6*2);});
  assertGLError(gl, gl.INVALID_OPERATION, "count + offset out of range 2",
      function(){gl.drawElements(gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 1*2);});
  gl.bindBuffer(gl.ARRAY_BUFFER, null);
  gl.bindBuffer(gl.ARRAY_BUFFER, vbo.vbos[1]);
  gl.vertexAttribPointer(n, 3, gl.FLOAT, false, 0, 0);
  assertOk(function(){gl.drawElements(gl.TRIANGLES, 5, gl.UNSIGNED_SHORT, 1*2);});
  assertOk(function(){gl.drawElements(gl.TRIANGLES, 0, gl.UNSIGNED_SHORT, 2*2);});
  assertOk(function(){gl.drawElements(gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 0*2);});
  assertOk(function(){gl.drawElements(gl.TRIANGLES, 1, gl.UNSIGNED_SHORT, 5*2);});
  assertGLError(gl, gl.INVALID_OPERATION, "count + offset out of range 3",
      function(){gl.drawElements(gl.TRIANGLES, 1, gl.UNSIGNED_SHORT, 6*2);});
  assertGLError(gl, gl.INVALID_OPERATION, "count + offset out of range 4",
      function(){gl.drawElements(gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 1*2);});
  vbo.destroy();
  assert(gl.NO_ERROR == checkError(gl, "vbo.destroy"));
}


</script>
<script id="vert" type="x-shader/x-vertex">
  attribute vec3 Vertex;
  attribute vec3 Normal;
  attribute vec2 Tex;

  varying vec4 texCoord0;
  void main()
  {
    gl_Position = vec4(Vertex * Normal, 1.0);
    texCoord0 = vec4(Tex,0.0,0.0) + gl_Position;
  }
</script>
<script id="frag" type="x-shader/x-fragment">
  precision mediump float;

  varying vec4 texCoord0;
  void main()
  {
    vec4 c = texCoord0;
    gl_FragColor = c;
  }
</script>


<style>canvas{ position:absolute; }</style>
</head><body>
  <canvas id="gl" width="1" height="1"></canvas>
</body></html>
