[Gtkradiant] Realtime lighting approach issues.

[gtkradiant@zerowing.idsoftware.com]

> Perhaps Bert Peers would be so kind as to lend us his BSP 
> renderer source.

I'm not sure how that would help -- it's just a dime-a-dozen
bsp renderer, using the lightmaps embedded in the compiled
.bsp, just like q3a itself ?
Ie, pretty useless without the compilation step.

> I like UnrealEd's approach to the textured 3d view...it just 
> draws the BSP. Any brushes/stuff that's changed get
> rendered as well, unlit.

How about using 3d textures to give a good impression
of light placement and falloff ?  For the cases where
q3map traces for direct-light contribution only, this would
be pretty accurate, save for the shadows.
If 3d textures sound too messy, a combination of a 2d and
1d may work too.

Bert