Ray Tracing on Programmable Graphics Hardware (RSX)?

[leechan25]

http://www.ce.chalmers.se/edu/proj/raygpu/index.php?view=home

"During this our resarech we have managed to implement a Ray Tracer running all it's image rendering calculations on a GeForce 6800 GT, using OpenGL and Cg. On this page you will be able to read more about the project and also download our thesis including source code and binaries for the ray tracer."

We should these methods use on the RSX too right with cell as it streamming processor?

 

[3roxor]

Ps3 won't be able to have full scene ray tracing.

 

[nAo]

Why should we use RT?
Sorry...I couldn't resist

 

[SanGreal]

Sure, but its not like its realtime or anything. Infact, this technique was slower than 3d studio.

On a positive note, I have the bhudda figurine he used as one of his examples

 

[Shifty Geezer]

Funny concept. "We've got a great, fast scanline renderer here. Let's make it chug away at raytracing instead!" Notice the severe lack of IQ in the screen-shots. I'm guessing this theory is for speeding up offline raytracing on workstations and has nothing to contribute to the realtime sector at this time.

 

[mckmas8808]

Sure, but its not like its realtime or anything. Infact, this technique was slower than 3d studio.

On a positive note, I have the bhudda figurine he used as one of his examples

You do show us. I would like to see it.

 

[therealskywolf]

Damm man, you keep on insisting in this Ray tracing thing.

 

[SanGreal]

Sure, but its not like its realtime or anything. Infact, this technique was slower than 3d studio.

On a positive note, I have the bhudda figurine he used as one of his examples

You do show us. I would like to see it.

what?

 

[leechan25]

Damm man, you keep on insisting in this Ray tracing thing.

Hey man I just want to what's possible. Problem?

 

[Sonic]

It's of course possible, but not anything remotely nice looking in a real time scene. The sheer power just isn't there even with all the graphical rendering power. Besides, there are easier ways to fake it.

 

[Fox5]

Why should we use RT?
Sorry...I couldn't resist

I have to ask that too, what can we do with ray tracing now that we can't do with shaders?
Especially because I think the demos for PowerVR's MBX looked better than these ray traced ones.

 

[vember]

I have to ask that too, what can we do with ray tracing now that we can't do with shaders?

Correct reflections/refractions of the surrounding world on complex geometry. We can only do that on planes nowadays (or appoximate it with cubemaps).

That's the main one IMO. Ray-tracing is also more efficient in terms of visible/rendered pixels, but since it's so slow that's not really relevant atm.

 

[3roxor]

I have to ask that too, what can we do with ray tracing now that we can't do with shaders?
Especially because I think the demos for PowerVR's MBX looked better than these ray traced ones.

Not much really..
With shaders you can exaggerate dark environments which wouldn't be nearly as dark in real life. Actual ray tracing would ruine sneak games like thief or Mgs etc.

 

[Fox5]

I have to ask that too, what can we do with ray tracing now that we can't do with shaders?
Especially because I think the demos for PowerVR's MBX looked better than these ray traced ones.

Not much really..
With shaders you can exaggerate dark environments which wouldn't be nearly as dark as in real life. Actual ray tracing would ruine sneak games like thief or Mgs etc.

I don't think Metal Gear Solid actually used darkness(or shaders for that matter), though splinter cell sure did.

 

[Inane_Dork]

I would take a real-time radiosity engine over a real-time ray tracing engine any day, but that's just me.

 

[blakjedi]

If its possible on Nv its possible on ATI too

 

[j^aws]

REYES realtime is closer to realisation than full, realtime RT, IMO.

 

[3roxor]

I don't think Metal Gear Solid actually used darkness(or shaders for that matter), though splinter cell sure did.

True, MGS wasn't a good example.

 

[ShootMyMonkey]

I would take a real-time radiosity engine over a real-time ray tracing engine any day, but that's just me.

Well, that's my general argument in favor of raytracing -- that there's more to raytracing than just recursive Whitted direct lighting. Raytracing itself extends well beyond direct illumination, even though extending out there requires obscene processing power.

Aside from the proper reflections/refractions, there's also the camera models since raytracing doesn't require an explicit affine perspective projection scheme, which in turn means there's no real necessaity to transform things into view space. Also, when scanning, you get perspective projection at a per-pixel level instead of per-vertex -- when you get into more complex camera models and extremely large sets, that makes a bigger difference than you might realize.

Even so, doing raytracing on a rasterizer GPU is little more than a pointless academic exercise. As much as it may have the raw floating point power, the linear streaming nature and its slow-ass bandwidth and need for all nature of data shuffling makes it quite a bit slower than software.

 

[nAo]

Even so, doing raytracing on a rasterizer GPU is little more than a pointless academic exercise. As much as it may have the raw floating point power, the linear streaming nature and its slow-ass bandwidth and need for all nature of data shuffling makes it quite a bit slower than software.

Slow-ass bandwith?! what are you talking about?
By the way once we'll have full MIMD pixel pipelines (or ALUs..) RT will be run much faster on GPUs than today.