THANK YOU CLINTON! I did not know that you could do that. That opens up doors!
I did the "negative" R, G, B with infinate lights, does the trick, will be handy for compositing rim lights and other effects later on in post production. My theory also is that with Normals, you can create some kind of false GI also in post.
The idea is you get one color, the color you want as the mask for any attribute in post within Blender Composite (say the B 255 value, and that would be the mask for a Z bloom or glow or something, a color bleed, or a rim light)
And.. this would all be rendered out in near realtime.
I still need to work on my pass/shader system... for animations (so the passes change in WS with a click of a button)... it is quite rigorious to set up with all the scripts and all...
Thanks for this Clinton
Ah, the lights are set to the "opposite" by putting in the value 255,0,255 if the other side be 0,255,0. I also put the constant shader in the normal texture to 128,128,128, a mid grey so the lights fit on nicely. Don't forget to delete all other lights.