in these papers you can find more information on my works on blender game engine
Blender Game Engine » 2D Filter » Custom Filter
Custom filters give you the ability to define your own 2d filter using GLSL. its usage is the same as built-in filters, but you must select "Custom Filter" in 2D Filter actuator, then write shader program into Text Editor and then place shader script name on actuator. see Fig 1.
Fig 1. Custom Filter
In Fig 1. you can see GLSL shader program for blue Sepia filter in Text Editor, and Custom Filter actuator that uses this shader program.
Also you can use these uniform variables in your shader program:
Blue Sepia Example:
uniform sampler2D bgl_RenderedTexture;
vec3(0.299, 0.587, 0.114));
If you write a custom shader program, you can send it to me via email.
hamed zaghaghi - hamed.zaghaghi(a) gmail.com