[straaljager]

Originally Posted by Voxilla

I'm still curious how current path tracing optimized for Fermi runs on Kepler.

Probably the same or worse, but that's not really relevant. A GPU path tracer that was developed and optimized on GT200 GPUs using "persistent threads" didn't run well on Fermi either . Unfortunately, every new GPU architecture requires a rewrite of the path tracing code to attain maximum (or even better) performance.

[Voxilla]

The thing is Fermi already had like two architectures:
- GF114 aka GTX 560
- GF110 aka GTX 580
The former has 8 SM the latter has 16 SM, also 256 bus vs 384 bus.
The former also shed compute in favor of graphics.
Now we have the GTX 680, which misleadingly sounds like the GPU is a derivative of GF110, but it is not. GPU marketing department (of both NV and ATI) is rather creative in a sense.
The GTX 680 is based on the GK104 which is like a supercharged GF114, and thus also not very well tuned at compute. Likely there will still be a GK114, think big monster chip, with wide memory bus. As the 28nm process still has too low yield for such a big chip, it has been postponed...

[Voxilla]

Ok, mistake above:
Logically the next big Kepler compute chip would be GK100

GF100 -> GF110 -> GK100 big chip compute optimized
GF104 -> GF114 -> GK104 smaller chip graphics optimized

[lecrab]

One thing that is not clear to me : why do you say that a bidirectional path tracer scales better than rasterization... why do you say that a path tracer scales better than rasterization?

ps: sorry for necro but the topic is interesting

[Dade]

Originally Posted by lecrab

One thing that is not clear to me : why do you say that a bidirectional path tracer scales better than rasterization... why do you say that a path tracer scales better than rasterization?

ps: sorry for necro but the topic is interesting

It is somewhat an old idea, probably based on the fact that ray/triangles intersection algorithm is O(log triangles_count).

I'm not sure if this argument is still valid nowadays.

I prefer arguments based on the quality, scene complexity and easy of use of (bidir) path tracing over classic rasterization. Real-time path tracing is already a viable option for simple scenes and I have yet to see a game engine that can match the quality of good path tracer.

May be my opinion is biased but the renderings of today game engines still look too "fake" to me.