custom light function in c++

Hello everyone,

I need a projector effect, which projects a colored movie sequence on a wall. Because light functions can only alter the brightness values and not the color values of a light I used the work around with three lights. A red light, a green light and a blue light, which display the red channel, the green channel and the blue channel respectivly. This is working fine as long as you do not activate volumetric lighting. For some reason the colors of the three lights don’t mix correctly in the volume. One color always overlays the other three.

Is there an easy work around to this or do I need to create a custom light function in c++. And if so, would this task exceed the capabilities of a c++ programming beginner like myself?

Or is the feature of light functions which can alter not only the brightness but also the color of a light planed for the next release?

Kind regards,
chrizzo