Global Illumination on next gen
- Thread starter fxtech
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Alejux said:Yes, of course. After all, those images in the link only took 2 to 4 hours to render. I'm sure the PS3 will be able to do it in real-time just fine.
offcourse width some degree of approximation
4 hour on today cpu , about 10 gflop vs 200-300 gflop specialized hardware
Unless that lighting model is free from penalties incurred by increasing scene complexity it may NEVER actually see use in games...
fxtech said:Alejux said:Yes, of course. After all, those images in the link only took 2 to 4 hours to render. I'm sure the PS3 will be able to do it in real-time just fine.
offcourse width some degree of approximation
4 hour on today cpu , about 10 gflop vs 200-300 gflop specialized hardware
It's the software that has to be specialised
Just for fun...
Assume today's general purpose is really, really unspecialized as opposed to specialized hardware, for ease of approximation, assume the GP CPU is only 1 GF 'real work' opposed to 300 GF 'real work' of the specialised hardware.
Assume 4 hours of work by the 1 GF GP CPU...
So the 300 GP system will render a frame in 48 seconds...
Need 14.4 TF to render a frame in 1 second...
Need 432 TF for 30 fps...
passerby said:Just for fun...
Assume today's general purpose is really, really unspecialized as opposed to specialized hardware, for ease of approximation, assume the GP CPU is only 1 GF 'real work' opposed to 300 GF 'real work' of the specialised hardware.
Assume 4 hours of work by the 1 GF GP CPU...
So the 300 GP system will render a frame in 48 seconds...
Need 14.4 TF to render a frame in 1 second...
Need 432 TF for 30 fps...
How about we find more efficient ways to render what we need?
How about we tesselate our geometry really fine (2-3 pixels/poly max) and then calculate lightiing only on a per-vertex basis and then fake it with goraud shading instead.
I would really like to see a game like that. Nevermind per-pixel global illumination or any other buzz-word-of-the-day, just a smooth-meshed world with smooth lighting. That'd be great.
I would really like to see a game like that. Nevermind per-pixel global illumination or any other buzz-word-of-the-day, just a smooth-meshed world with smooth lighting. That'd be great.
Guden Oden said:How about we tesselate our geometry really fine (2-3 pixels/poly max) and then calculate lightiing only on a per-vertex basis and then fake it with goraud shading instead.
I would really like to see a game like that. Nevermind per-pixel global illumination or any other buzz-word-of-the-day, just a smooth-meshed world with smooth lighting. That'd be great.
What you're describing is sounding more like REYES to me!
Guden Oden said:How about we tesselate our geometry really fine (2-3 pixels/poly max) and then calculate lightiing only on a per-vertex basis and then fake it with goraud shading instead.
I would really like to see a game like that. Nevermind per-pixel global illumination or any other buzz-word-of-the-day, just a smooth-meshed world with smooth lighting. That'd be great.
By the time someone comes up with a way of doing tha tproperly, there won't be a need to worry about that, cause eventually pixel and vertex shaders will be the same thing and share the same resources.
We can speculate about a lot of stuff, but one thing is for sure, you won't see any True Global Illumination complex algorithms such as photon mapping, or radiosity next gen. "Simple" (And good) ray tracing seems already out of reach for next gen machines, so expecting caustics calculation in top of it, might be, to say the least, overkill.
On the other hand, you can achieve effects close enough to good GI, without using real GI, you just have to use a precomputed method,
precomputed radiance transfer (a.k.a PRT), using, Spherical Harmonics* lightmaps. The effect is quite satisfying, and it's quite cheap, from a calculation POV.
For instance there's a cool PRT demo for the PSP, a video of it can be found at IGN (It's called, IIRC, Harmonic City), which prove that the effect is not really hard to implement.
Also, Conker Live and Uncut, on Xbox, use also the same technique.
The only problem of this technique, some not so important (for me) lighting errors aside, is the size of those precomputed SHLM.
(*I know some developers here who will cringe when they'll read this word)
On the other hand, you can achieve effects close enough to good GI, without using real GI, you just have to use a precomputed method,
precomputed radiance transfer (a.k.a PRT), using, Spherical Harmonics* lightmaps. The effect is quite satisfying, and it's quite cheap, from a calculation POV.
For instance there's a cool PRT demo for the PSP, a video of it can be found at IGN (It's called, IIRC, Harmonic City), which prove that the effect is not really hard to implement.
Also, Conker Live and Uncut, on Xbox, use also the same technique.
The only problem of this technique, some not so important (for me) lighting errors aside, is the size of those precomputed SHLM.
(*I know some developers here who will cringe when they'll read this word)
What you're describing is almost another of thoses buzz-words-of-the-day, it's REYES.Guden Oden said: