Custom lights?


Has anybody attempted to model light patterns beyond simple point or spot lights? For example, go to a fancy piece of architecture near you and look at some in-ground light fixtures. The light footprint they emit is probably restricted to some pattern.

I attempted this myself several years go, and basically my solution involved ray-tracing from the light source to the destination surface, and encoding the intensity’s into a texture, in real time. This is fine for one light, but throw in rotations and multiple lights where you have to combine textures it becomes messy.

Does anybody remember Ron Frazier’s per-pixel lighting technique from back in the day of register combiners? He was doing something similar by capturing the pattern in a cube map. I don’t know how this would scale to multiple fixtures. If there was a modern day variation of this, that would be great. I realize there probably is, but I don’t know enough about shaders and so forth.

So any thoughts, ideas, example on how I could model custom light patterns in OpenGL (given I have a file describing light intensity at each angle or something), and that would scale up to support multiple lights?


The simplest way would be to simply project a texture of it, used along with a shadow depth map you could get some pretty decent results.
And it would scale up to a lot of lights.

Rotated vectors in a cube map can give you a nice disco effect.

(staying alive… staying alive…)

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