I've got my path tracer working great for a single light, but I'm having trouble coming up with a solution for scenes with multiple lights. My first thought was to just send a ray to each light and sum up all the contributions. That worked fine, but it was very slow, especially for many lights. I tried researching techniques for working around this, but I found very little. I did find that some renderers weight each light and then pick one based on how much light they might contribute, but I couldn't find any detailed process of how that's actually done.

So my question is, could someone give me an overview of how this might be accomplished, or point me to a resource that goes over multiple lights?

Thank you!

I've got my path tracer working great for a single light, but I'm having trouble coming up with a solution for scenes with multiple lights. My first thought was to just send a ray to each light and sum up all the contributions. That worked fine, but it was very slow, especially for many lights. I tried researching techniques for working around this, but I found very little. I did find that some renderers weight each light and then pick one based on how much light they might contribute, but I couldn't find any detailed process of how that's actually done.

So my question is, could someone give me an overview of how this might be accomplished, or point me to a resource that goes over multiple lights?