Valve lighting paper from SIGGRAPH 2006

Eric Chadwick

I remember seeing this presentation before, but the paper from last year's SIGGRAPH has some new pictures.

http://ati.amd.com/developer/siggraph06/Mitchell-ShadingInValvesSourceEngine.pdf

I like the "variable luxel density" images, smart. They also showed more pics about their "radiosity" specular effect, comparisons of their ambient cubes to others' diffuse cubes, etc.

Worth another look.

CrazyButcher

oh cool stuff, thx Eric

also from siggraph 06, not lighting but GRASS
http://www.irisa.fr/bunraku/GENS/kboulang/grass.html

however keep in mind following statements "We achieve real-time frame rates with a Pentium D 3 GHz processor and a GeForce 7800 GTX video card, 1024x768 resolution and 4X antialiasing. We obtain 10 to 55 frames per second for the park scene, 20 to 250 frames per second for the football field."

Which means it isn't really game ready yet

Blaizer

Really interesting, thanks a lot Eric and CrazyButcher.

I think that the method of creation of grass can be really optimized for realtime.

Uly

Good reads, thanks guys.

poopinmymouth

What's funny, is that while it looks like they spent a lot of time on it, I didn't notice it one iota in game. I thought the assets looked just like a standard quake 3 game with the ambient turned up, and then some normal maps popped on very lightly. I can notice it in their paper when they show the model with the texture off, in the "before after" shots, but once they apply the texture, it looks very old school to me. Not that I minded playing the game, I liked it, but it's a shame they spent all that time, and it wasn't more noticeable.

ElysiumGX

To me, Valve's games feel more realistic. While many games throw harsh lights and dark shadows everywhere with baked textures to emulate the look of realism, Valve makes these small light adjustments to give their games a more believable atmosphere. It helps to draw you into the story and action.

Eric Chadwick

Which game did you play Ben? HL2's character lighting didn't impress me either. OK here's a shot.


I haven't played Episode One though, from the side-by-side shots in the paper it seems like the lighting has come a long way, like take a look at page 38.

The Half-Lambert looks nice too, I like the soft terminus.

poopinmymouth

I played HL2 and Ep 1, and I didn't even notice that they changed the lighting. I think it might be that they put too much contrast and baked in lighting in the textures, but I also think their shader doesn't capture enough of the volume of the normals/geometry.

That above shot to me, I can barely tell it's not just a model with a diffuse map only. I can see some extra detail in the dude's face, but that's about it as far as per pixel stuff.

MoP

yeah from playing HL2, the only time i noticed normalmaps was on the antlions, and on some environment-mapped tile walls (like they showed in the paper there).

that said, i love how the game looks and the whole style of it, it is very realistic and atmospheric, but IMHO 90% of their normal maps went to waste, seems like a diffuse map would look nearly identical in most cases.

Eric Chadwick

Yeah, that's just HL2, before the new tech.

Could be your hardware too, Jason was saying in the paper that only cards supporting pixel shader 2_b can render the new shader.

Hmmm, want to find some screenshots of Ep1 now.

Eric Chadwick

Hmmm. The shots on Valve's site look like the old lighting to me. I did find this one though, looks like it _could_ be using the new shader. Anyhow, love these tech papers.