Many lights question

One thing I’m not sure how it is done in jme:

  1. When i have 5 lights I understand it right that the scen gets renderd 5 times for each light, yes?
  2. When I have two objects, each attached with one light to it will it be rendered once or twice then? Since basically both lights are independent?
  3. When i havea scene with many obects and two lights with a radius that only intersects a bit what happens? 3 renderings ? 1 per light?

    Question why im asking is, that I need to create a city at night for my game, and wonder if I can use many lights if i either have some kind of partitioning in the scene so each geometry is only lit by one or two.

    Or if it is better to use very low radius for the light so there are only few overlapping lights.

    Or if it doesn’t matter and I have to swap to some kinda of lightmap system.

Its exponential afaik, so you have three render for two lights I think. Deferred rendering only grows linear in terms of performance loss, so you will want to switch to that when its done. Light maps are of course always the best performance but are obviously not as flexible. Still light maps are whats used in most games to get the very detailed rooms etc. one sees sometimes.

does jme support lightmaps ? e.g creating lightmaps when the game starts and then applying them to models ?

Well define support, you can make lightmaps und use them if that#s the question, but I’m pretty sure there is no build in support for that.

Made a few tests:

Actually it mkeas no differe3nce if i have

one light in rootnode and 200 objects

or 200 lights attached each one to one of the 200 objects.

→ Conclusion a high detail City is probaly very much possible at night, but Spatial partitionling must be done with lightsrange/radius in thought, so that at max 2-3 lights radiuses intersect. Then the total light count makes nearly no problems at all.

tralala said:
does jme support lightmaps ? e.g creating lightmaps when the game starts and then applying them to models ?

Lighting and Unshaded material supports lightmaps, but baked light maps, made with another software.
The terrain shader does not support lightmaps