Controlling radiosity bounces saved to lightmap

[ix-ir]

Does anyone know if it's possible to do a light map compile with bounce and save only the light map data for light bounces after the first with q3map2?

[cha0s]

Afaik, there's no way to do this directly. You could however compile the map twice - once with, and once without bounce - and export the lightmaps of each BSP (-export switch). Then subtract the lightmaps of your BSP without bounce from the one with bounce (with a Photoshop batch, or whatever) and import the result into your BSP again (-import).

I'm not entirely sure why you'd want to do that, though 0_o

[urgrund777]

I could see one reason. We once tested a solution where only indirect lighting was baked, but the source light remained as realtime. So, you got your standard realtime shaders running for the lights, allowing for view dependant effects like specular whilst retaining some nice fill/ambient light with only bounced lighting in the lightmap. ...not really applicable to Q3 though? :S

[$NulL]

Then subtract the lightmaps of your BSP without bounce from the one with bounce (with a Photoshop batch, or whatever)

You have to remember that the lightmap arrangement is recalculated after each bounce, so there's no guarantee that pre and post bounce lightmaps will still be congruent.


You can get q3map2 to save the light entities produced by each bounce stage with the -dump argument, maybe you can get whatever information you want from those.