Alternatives to point light lighting?

Soooo…



I was playing a game today and noticed that the technique for point lights seemed to NOT be point lights at all.


  1. My initial guess is projective texturing for the light glow, but not totally sure this is (or is not) the case. This could get more expensive than just rendering multiple point lights.
  2. I guess you could use texture splatting and the GPUAnimationFactory shader to produce the same effect (potentially) being as the glow was animated (they were simulating torches).
  3. Create extra geometries to apply the animated textures to. and place them appropriately. This would be a little harder to maintain (depending in the complexity of the scene, however, it would be the easiest way to produce the effect using animated textures and opacity).
  4. Add light placement markers and use a depth buffer to adjust the texture by proximity. This would take less render passes, but the shader would potentially be slower per render…



    Anyone played around with alternate methods of producing light “glow” other than using actual lights? And would you be willing to pass along your approach? At least conceptually?



    Anyways… could be an interesting idea. Gonna play around with it when I have some time but would love some input, ideas, etc for approaches I haven’t considered.
@t0neg0d said:
I was playing a game today and noticed that the technique for point lights seemed to NOT be point lights at all.


Curious what made it seem this way.

Yeah, I’m also curios. Could you post a screenshot or something, I’ve having a hard time picturing what you are getting at :slight_smile:

@pspeed @kwando

The game is Torchlight II… and I’ll grab a quick video on YouTube. You’ll spot what I’m talking about right away, though the effect is just great… it is definitely NOT produced by lights. The edges of the illuminated area are animated in a way that (to me) looks a heck of a lot like a shader based texture deformation (I can spot these a mile away after all the time I spent working with them… they all have a fairly uniform pattern, even when cascaded) Brb with a vid…

Ugh… ok… lots of videos, however, not are high enough quality to be able to see how the lights look… aside from you say… yep… they’re passible, but not actual lights. I did, however see a vid comparing this and Diablo 3. Tbh, I’m fairly sure Diable 3 isn’t using point lights either (from the vid). The player light radius in both are definitely point lights, however fires, torches, magical “glow” effects are not. I’d love to know what you all would guess they might using, because it seems a very inexpensive way of producing lots of small-radius lights that add to the overall atmosphere of the game without killing framerate.



Check out the comparison vid and see whatcha think:



http://youtu.be/Y1Cdd6ZYKIU

I saw lots of baked in lighting with some kind of noise applied. I only watched about a third of the way through.



If there is dynamic lighting that exhibits the effect then I didn’t see it and don’t have time to watch the whole video.

@pspeed said:
I saw lots of baked in lighting with some kind of noise applied. I only watched about a third of the way through.

If there is dynamic lighting that exhibits the effect then I didn't see it and don't have time to watch the whole video.


It's subtle and didn't really come across in the video. Maybe I can capture it in a short video. I'll see what I can do tomorrow.

I think they are using point lights, maybe they are just moving them around and/or varying the radius?

Unless you’re talking about the glows on the light source itself, that’s just a billboarded quad.

The reason I thought baked is because it didn’t look like it was affecting the characters as they walked through it… at least not like a light would. They got the overlay and maybe their overall brightness changed… but not real directional lighting.



It was hard to see, though.