thanks Hyllian, much appreciated!
edit: not to hi-jack this thread but do you have .fx/hlsl variants of those shaders? I could port them myself but if you already have them that would be even better
double-edit: apparently i cant read. I will port them over to .fx 
thanks!
Ok. I don't know much about glsl format, so I think you can do this task.

BTW, here some screenshots I'm getting with this filter:
Original.........................
2x..................................
4x
Original.........................
2x..................................
4x
