text: 
  /*
  ** Copyright (c) 2012 The Khronos Group Inc.
  **
  ** Permission is hereby granted, free of charge, to any person obtaining a
  ** copy of this software and/or associated documentation files (the
  ** "Materials"), to deal in the Materials without restriction, including
  ** without limitation the rights to use, copy, modify, merge, publish,
  ** distribute, sublicense, and/or sell copies of the Materials, and to
  ** permit persons to whom the Materials are furnished to do so, subject to
  ** the following conditions:
  **
  ** The above copyright notice and this permission notice shall be included
  ** in all copies or substantial portions of the Materials.
  **
  ** THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  ** EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  ** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  ** IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
  ** CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  ** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  ** MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS.
  */
  
  
  attribute vec4 gtf_Color;
  attribute vec4 gtf_Vertex;
  uniform mat4 gtf_ModelViewProjectionMatrix;
  varying vec4 color;
  
  void main (void)
  {
  	vec3 c = floor(1.5 * gtf_Color.rgb);   // 1/3 true, 2/3 false
  	color = vec4(vec3(not(bvec3(c))), 1.0);
  	gl_Position = gtf_ModelViewProjectionMatrix * gtf_Vertex;
  }
  