Hi all,
I’m developing a car game and I’l like to add the effect of neon lights glowing under the car model like the pictures linked below. I tried by adding some point lights in child light nodes but, although the visual result was good, this is not fast enough (fps dropped dramatically). Any idea about how this could be implemented efficiently in jme3?
Thank you all.
pic1
Yea every light essentially is another render pass for the objects it is attached to. You can try Deferred Shading as mentioned in this thread. I don’t think the source is available however, but you might be able to beg the author, he’s a nice guy 
You could attach the light to the terrain only, and place it where the car is. Then it will just do that extra pass on the terrain. Or terrain and car. But you don’t want all those lights at the root node, then your whole scene is rendering many times.
Would it be possible to do this as some sort of glow effect rather than actual lighting? That’s a whole area I’m planning to look into actually as I’m wanting the ability to make certain areas of the scene glow but I don’t need a full lighting effect.
It should yeah but I don’t think you get the reflections on the floor.
From what i have learned up to now programming games:
When you see a something which looks realistic, think about how to fake it.
For example if you don’t need lighting the wheels or other cars, why not draw a quad on the floor, ir using something like: http://hub.jmonkeyengine.org/groups/contribution-depot-jme3/forum/topic/projective-texture-mapping/ for drawing a texture on the ground.
Why not use a glowing texture for underneath the car’s model?
Why not both? Projective map a glowmap on the terrain. (And attach a light to the car)
Thank you all for for comments. Finally I implemented it using the projective map technique linked by @zzuegg