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.
  */
  
  
  #ifdef GL_ES
  precision mediump float;
  #endif
  varying vec4 color;
  
  void main (void)
  {
      const vec2 max_c = vec2(0.5, 0.5);
      vec2 c = color.rg;
      if(c[0] < max_c[0]) c[0] = max_c[0];
      if(c[1] < max_c[1]) c[1] = max_c[1];
  
      gl_FragColor = vec4(c, 0.0, 1.0);
  }
  