The script GLSLConverter.py is a simple python script that can be used to
replace GLSL built-in uniforms into OIV shader API calls. It provides a way
to port shaders that work in Open Inventor 9.x to shaders that work in Open
Inventor 10 as well.

The usage is: python GLSLConverter.py filename

Where filename is the path to a file that needs to be converted, or a folder.
If it is a folder, the script will find every file whose name ends in '.glsl'
and apply the single-file operation on each. After converting, the original 
file name is renamed to filename.origin and the parsed file takes in place of filename.
With the '--remove-original' option, the filename.origin file is removed by the script.

Notes:
- only built-in uniforms exposed in the Open Inventor Shader API are
  replaced and others uniforms should be handled in another way.
- this script works line by line, so if you have a built-in varying
  assignment on multiple lines, it will not work (no replacement will be done).
  Examples:
  { // NOT OK
    gl_FragColor.rgb = color;
    gl_FragColor.a = alpha;
  }
  { // OK
    gl_FragColor = vec4(color, alpha);
  }

  { // NOT OK
    gl_FrontColor = vec4(1.0, 0.0,
                         0.0, 1.0);
  }
  { // OK
    gl_FrontColor = vec4(1.0, 0.0, 0.0, 1.0);
  }
