There was an older thread about the luminosity shader of the wiki. If i remember correctly they said that this shader only works on level geometry (and indeed it does for me).
In Antwort auf:
or you could use a channel (alpha or r/g/b of another texture) and use the "mul" instruction to let only masked parts be visible
This sounds interesting. But I don't know that much about shader programming and i dont know how time consuming this would be. But if somebody has the time (and desire 
) to make this effect.. this would be great!
