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environmental cubic lighting

Started by quasty Oct 5, 2006 at 1:12 PM 0 replies 700+ views

Original Post

Oct 5, 2006 at 1:12 PM

Hi, I wanted to reduce the ambient lighting component in my scenario, but add more diversity in lighting without adding more lights. With this premise I stumbled upon "environmental cubic lighting" and this seems to be what I was looking for. As I understood it I've to create somewhat of a cube map-light map and with the normal of a vertex indexed I get a color value of that light-map appropriate to my position? If I want to use this cube map for the lighting of my ambient term, do I've to multiply it with the material attributes (for example gl_FrontMaterial.ambient * CUBE_MAP_PIXEL) or just add it to the final color of my pixel? Any ideas about tools specialized or which can be of some help in the creation of these cubic light map? Is it possible to use something like this also for diffuse and specular models? Not to replace a real lights, but to extend it with a bit of a more complex look? Thank you very much.

Guoshima

Oct 6, 2006 at 2:33 AM

hmm if I get it correct you want to make your ambient look more interesting. The easiest solution, would be I think:
- For static parts of your scene you can use radiosity light maps (created in 3DS Max or you can write your own radiosity renderer). You can use Half Life 2's method to create Radiosity Normal Mapping (see developer part on ATI site. There you can find information about this). RNM allow you to have some sort of normal mapping on pre calculated lighting. This works oké if you exagerate your normal maps a lot. Specular won't be possible like this I'm afraid .. anyone a suggestion for this ?
- For dynamic object you can use the Environment Cube Maps, or Ambient Cube Maps. You can generate these very easily from your radiosity maps, by creating cubemaps at certain spots in your levels (artists place these), and the creation is a preprocess step. Then in game you search for the nearest ambient cubemap for your dynamic object and use the normal to lookup the color. Interpolating between two cubemaps can become hard but there is enough information about this ..

Regards,
Kenzo

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