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Get it while it's still hot...
Get it while it's still hot...
PGR3 update
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I was pretty sure Laa-Yosh said there was no way ambient occlusion could be done on realtime applications on present or near future architecture... Not saying the guy's lying, i'm saying that it's quite impressive
_phil_ said:you can fake a lot of cases of ambiant occlusion with a very cheap dirtmap,you know ..
Well it looks good.
Anyone remember the Ambient Occlusion demo on PSP? There's certinly trickas that cen be used, but i don't know how dynamic they are. When the car drives out from a high-rise street and next to an open park, how well does the lighting change? I think it could be simulated closely enough with a few different textures and blending between them based on an approximation of the surrounding area.
V3 said:london-boy said:
I was pretty sure Laa-Yosh said there was no way ambient occlusion could be done on realtime applications on present or near future architecture... Not saying the guy's lying, i'm saying that it's quite impressive
Perhaps you should reread what you quoted.
:| just did... ?
london-boy said:
I was pretty sure Laa-Yosh said there was no way ambient occlusion could be done on realtime applications on present or near future architecture... Not saying the guy's lying, i'm saying that it's quite impressive
It says it's being done with a tool ie non realtime. This precalculated data is then plugged into the game engine. Spherical harmonics works the same way using precalculated datasets. It only works on static geometry and in this case it's a wheel.
PC-Engine said:
Oh that explains it
Fake Ambient Occlusion is probably one of the easiest 3D rendering method that could be implemented in a (next-gen) engine.london-boy said:
And in 99% cases, in a game scene, I'd say it would look nigh identical compared to the offline solution.
Spherical Harmonics! That's the technique used in the PSP demo. It looked very effective. I think it was precalculated for the scene on the PSP (rather than precalculated on a development workstation).PC-Engine said:
This could be done, so levels are loaded, lighting calculated, and then you play. Though it might be quicker to pre-calc and save on the game disc. (?)
Spherical harmonics are used in a lot of stuff, and are a very generic mathematical term.Shifty Geezer said:
The technique used in this PSP tech demo should be referred as PRT (Precomputed Radiance Transfer).
Yeah, I know, I'm nitpicking. But nitpicking is cool.
It's precalculated in that you're not calculating it in real time. Like lookup tables for sin and cos from many moons ago. Where you pre-calc it doesn't matter I guess.
I'd guess, in areas of shade (based on proximity of objects?) you'd decrease the alpha of the occlusion map, and vice versa, adding a layer of darkness to the surface.
I'm not allowed to show you the difference between a precalculated static occlusion map and dynamically calculated (raytraced) occlusion... but on characters, it's very very evident.
Edit: that is, using images from our current work, guess it wasn't clear without this bit
Think about this... On the side of a character's body, there's a given amount of indirect lighting from the sky and the enviroment when his arm is raised. As the arm comes down, it slowly starts to occlude this light, and when it's resting near the torso, almost 90% of the light that was previously there is gone. If the incoming light was direct, there'd be a shadow, but I'm talking about indirect light, stuff like an ambient cube map in HL2 or additional fill lights.
Or, on that image for example, there should be a very soft contact shadow under the wheel, where it touches the ground, and an even larger and softer and blurry contact shadow from the car's body; and those 2 contact shadows should be gone if the car gets up in the air somehow.
It is a subbtle but very dramatic effect, exactly because it goes a long way in tying dynamically interacting objects together.
Edit: that is, using images from our current work, guess it wasn't clear without this bit
Think about this... On the side of a character's body, there's a given amount of indirect lighting from the sky and the enviroment when his arm is raised. As the arm comes down, it slowly starts to occlude this light, and when it's resting near the torso, almost 90% of the light that was previously there is gone. If the incoming light was direct, there'd be a shadow, but I'm talking about indirect light, stuff like an ambient cube map in HL2 or additional fill lights.
Or, on that image for example, there should be a very soft contact shadow under the wheel, where it touches the ground, and an even larger and softer and blurry contact shadow from the car's body; and those 2 contact shadows should be gone if the car gets up in the air somehow.
It is a subbtle but very dramatic effect, exactly because it goes a long way in tying dynamically interacting objects together.
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