GPUs Will Process Physics, ATI Says

It would be very nice if you do it. Thanks.

 

scuse the singing + soundquality (ill be getting a soundcound card soon, so will record some more crap)
http://rapidshare.de/files/22790157/video_B.avi.html
http://www.filefactory.com/?b564b1

the asteroids are in the second one.
these vids are from 7 months ago, ive changed the gameplay somewhats its more of a typical shoot-em-up, the main problem with having a thirdperson viewpoint is u cant aim that well (necessary in a fast paced game)
im curious how gears of war solves it, im 99% theyre shooting from the first person view, which may work with fast bullets but what about missiles etc?

 

Firingsquad have posted an interview with Havok regarding the ATI announcement:

 

Very cool zed. Thanks for the links. A couple of questions if you don't mind. You mentioned somewhere that the asteroids would blow up from point of impact. Did you get that too happen?
Is it right to say that each asteroid is unique? and a gameplay question: What is happening when the ship parks near a roid and the green light comes on... mining?

 

FYI, here's a few notes I jotted down from Nvidia's GPGPU talk in the Advanced Visual Effects with OpenGL tutorial at GDC, which I thought might be relevant to this discussion. They're talking about the Havok FX implementation in this case. Unfortunately I didn't get a copy of the actual presentation.

- Each collision requires >1500 pixel shader cycles, and ~100 texture fetches
- Uses CPU for collision detection, GPU for integrating positions/velocities and resolving collisions
- Said collisions tend to be a sparse data set; need to either pixel gather (use dynamic branching) or vertex scatter (render single pixel primitives at particular co-ordinates); which one is better depends on matrix size and distribution of collisions
- Showed a graph of performance vs. collision matrix size, which stair-stepped with every 1k increase in matrix size (appeared to illustrate the effect of thread size for dynamic branching)

And a couple more notes from Havok's GDC presentation on Havok FX:

- Makes collision physics a data parallel task by grouping collisions into sets of unrelated pairs that can be processed in parallel (usually 1000s of pairs per batch), then iterating until all pairs have been processed
- Position/velocity integration is 100% data parallel, collision detection is 70% data parallel, and collision solving is 99% data parallel[/font]

And finally, a link to ATI's white paper on asymmetric physics processing which gives some insight into their approach:
http://www.ati.com/technology/crossfire/promotions/physics/Asymmetric_Physics_Processing_with_ATI_CrossFire.pdf

 

100 texture fetches? Is that correct?

 

This doesn't contain as much detail as we might hope:

http://download.nvidia.com/developer/presentations/2006/gdc/2006-GDC-NVIDIA-Havok_FX.pdf

More struggles with collision capabilities:

http://www.continuousphysics.com/Bullet/phpBB2/viewtopic.php?t=321&sid=daea1fabd4eaaebfb605d18f8f162a60

Jawed

 

cheers
well the videos dont have much relation to what the game is like now, see gameplay footage here
http://www.filefactory.com/?35b6ab (no music, btw im rendering about 200k polygons/frame )
i've had to change it from a 3d shooter where u can move up + down, to a more traditional 2d one where everything happens on the xz plane. the reason for this change was it was to difficult to play, to aim with a 3rd person view is practically impossible to do fast accurately, the only solution was to make a firstperson camera viewpoint (which didnt appeal to me, as i wanted more of an oldskool feel) or implement some autoaim (which i did have in the videos u may notice) personally though i hated autoaim, as it dumbed down the game to much and aint really in the spirit of a shoot-em-up.

asteroid - i dont know about blowing apart from the point of inpact, the explosions aint realistic, im just doing the game 'asteroids' approach replace a larger asteroid with 3 smaller ones at the place of inpact
also the asteroids are procedurally generated so they can be unique but im just creating a pool of 16 different types, for speed reasons

 

ExtremeTech, [H], Xbit, and Techpowerup have headlines about this, with neither of them bothering to notice the job listing is nearly a year old now.

http://www.extremetech.com/article2/0,1558,1979051,00.asp

http://www.hardocp.com/news.html?news=MTk2NTEsLCxobmV3cywsLDE=

http://www.xbitlabs.com/news/multimedia/display/20060620235215.html

http://www.techpowerup.com/index.php?13408

 

Looks like that everybody is searching for something to fill the summer hole.

In this case I should tell you something new but I need to refer to the job listing too. You may remember that the want somebody who have experience with HLSL. HLSL is the one and only shader language for D3D10. Maybe you have heard about the GPGPU sample in the D3D10 part of the SDK. One interesting part of this sample is that it creates a head less device. A new feature that allows using a GPU without output something to a window or screen. So far nothing new at all but after a short question to Microsoft I now know that the spec allows to write D3D10 drivers for non GPU device. Any company can take a strong math copro put it on a card and write a D3D10 driver for it to make it’s power useable with the D3D10 API. This could make DirectPhysic to a D3D10 extension.

 

Demi, did you just suggest that PhysX might be compatible with a new MS DirectPhysics? Sometimes I think you and Ail could sit next to each other and rule the world without anyone else catching 10% of your meaning.

DailyTech has a piece too this morning, but they went up a notch in my (not too high) estimation, as at least they pointed at the fact that the listing is nearly a year old.

Having said that. . .if I was the suspicous type (who, me?), I might wonder if there's a hand in the background somewhere that thought it might be useful to get this some more visibility right now even though they didn't want to show any new facts --but that doesn't mean there aren't some new facts somewhere. . .

 

This is something that is not impossible at all.

At least Microsoft will allow something like this. But I have to add that the person at Microsoft told me too that he is not aware that there is anybody outside the GPU business currently working on a D3D10 driver for their hardware. This mean that the D3D10 driver for the non GPU path is not tested and may not work correctly in the current version of Vista/D3D10.

 

Anyone see much chance this'll work with IGPs someday? It would be nice to get some bonus from otherwise wasted silicon, I don't know, perhaps that could even motivate people using IGPs to get AIBs.

 

Oh btw, hi everyone, long time listener, first time caller

 

"Someday" is so open-ended. At the moment, ATI isn't going below X1600 for physics support, and their current IGPs are all below that.

With next year's DX10 IGP part? Well, could be I suppose. . . I could see that being a "decelerator" tho, depending on the viddy card it was paired with. . .

 

Yes, with Havokfx only requiring SM 3 it seems any DX10 IGP (or Aero capable, maybe?) would be more than sufficient...

notwithstanding. I would expect some acceleration out of a 4 pixel pipe part from one of the big 2, but I guess only if it had batch sizes/ dyn branching/ threading reasonably in line with it's bigger cousins, which probably puts someday quite a few years back. Would anyone hazard a guess as to when we'd see something X1600ish in an IGP?

 

Speed-wise, next year for sure. Maybe even end of this year.

 

From who?

 

All of them. We already have X1300-level stuff, hell even the S3 integrated 4-piper is on that level with much better video to boot (EDIT: sucks in 3D as just measured). So just by logical extrapolation, the additional 30-50% speed till next year sounds realistic, don't you think?

 

Well, I haven't noticed that IGP scales at the same rate/frequency as the top, alas. Of course, I'd prefer that you be right --I've been generally concerned that the gap between the bottom and the top is not a good thing. And Vista would certainly be an opportunity to address it.

ATI's current IGP is a two-piper, not a 4, and that's before you even get into the 3-1 shader thingy with X1600. I notice their next IGP is still described as "X700" core, which still doesn't give a lot of comfort for getting to X1600-level. Will their DX10 part, scheduled for next year, get to that level? I'd like to think so, but aren't prepared to put it in my pocket yet. But that one is certainly "next year", so I was curious who you had in mind for end of this year for that level.

Has anyone benched the S3 one yet?