AMD to Demonstrate GPU Havok Physics Acceleration at GDC

[ShadowFold]

Cell Factor doesn't work on nvidia PhysX. I tried.. And I forgot Cryostasis, but it's really the ONLY game that uses it well.. I remember trying the demo and it was ok, but ran pretty bad on a gtx 280 and didn't really see anything cool besides the mercury, I mean water.

 

[DarkMatter]

No its not. Phsyx is CAPABLE of it, but they simply cant do it. I'll try and explain it more simply.

Path 1: Make the game use a generic physics engine, for people without CUDA (old Nv cards, ATI) - Physx does as little as possible in this example, so that they dont need to duplicate any coding (two physics engines for the same items) - thats when you have items that dont collide together.

path 2: make two engines coded for everything. When physx is enabled everything moves over, and everything can interact with everything else.


If you were strapped for cash and time as a game developer with an unknown, brand new concept for a game... which would you take?

In Mirror's Edge when you walk on a cloth it interacts with your character. That is when extensive PhysX is enabled and when not, I suppose it doesn't interact, because current CPUs don't have enough power to handle that kind of extensive use. If it'd be using another engine, like Havok it wouldn't interact either, you need stream power to do so, be it a GPU or a PPU. So I'm lost and don't know what are you trying to say.

Anyway, in path 1 you can take PhysX just as well as you could take any other, namely Havok, and PhysX is free. If you are not going to make anything special, the free version of PhysX, the one without access to the source code, is just enough.

 

[DaveK]

Woot go Havok! They're Irish Might stop by their office someday.

 

[Mussels]

In Mirror's Edge when you walk on a cloth it interacts with your character. That is when extensive PhysX is enabled and when not, I suppose it doesn't interact, because current CPUs don't have enough power to handle that kind of extensive use. If it'd be using another engine, like Havok it wouldn't interact either, you need stream power to do so, be it a GPU or a PPU. So I'm lost and don't know what are you trying to say.

Anyway, in path 1 you can take PhysX just as well as you could take any other, namely Havok, and PhysX is free. If you are not going to make anything special, the free version of PhysX, the one without access to the source code, is just enough.

alright, my info on the cloth stuff could be wrong.

If you want to test it, test how it works once a few holes are in the cloth - i have a suspicion they're using another physics engine for the collision detection on top of physx (walking on the cloth wont change between physx on and off, for example)

 

[DarkMatter]

Cell Factor doesn't work on nvidia PhysX. I tried.. And I forgot Cryostasis, but it's really the ONLY game that uses it well.. I remember trying the demo and it was ok, but ran pretty bad on a gtx 280 and didn't really see anything cool besides the mercury, I mean water.

It doesn't matter that CellFactor doesn't work on Nvidia PhysX, it's just an example of what a gane with PhysX enabled can do. If the developers wanted, they could port it to Nvidia PhysX.

About Cryostasis I have seen it playing in a 9800GTX+ and it ran well, so I dunno why it ran bad on a GTX280.

Anyway, as I have already said, you won't see any extensive implementation of either of the GPU physics until both GPU companies support them. And that's lame, and I will never never never understand why AMD went the Intel route instead of the PhysX route. I could have understood if they made their own engine, but they took Havok just after discarting PhysX because was propietary and not an open standard, well, what's Havok?? Also the Havok engine will never be optimized to run on GPUs, only in x86, because even Intel's GPU will be x86.

 

[DarkMatter]

alright, my info on the cloth stuff could be wrong.

If you want to test it, test how it works once a few holes are in the cloth - i have a suspicion they're using another physics engine for the collision detection on top of physx (walking on the cloth wont change between physx on and off, for example)

Man it's all physics. Period.

 

[Mussels]

Man it's all physics. Period.

its a very different story if they're using multiple engines, to cover physx flaws.

 

[DarkMatter]

its a very different story if they're using multiple engines, to cover physx flaws.

They are not using two engines. Where have you seen that PhysX has no collision? That's BS, it HAS. It's in the features list and everything.

Complex rigid body object physics system

The rigid body dynamics component enables you to simulate objects with a high degree of realism. It makes use of physics concepts such as reference frames, position, velocity, acceleration, momentum, forces, rotational motion, energy, friction, impulse, collisions, constraints, and so on in order to give you a construction kit with which you can build many types of mechanical devices.

* Collision primitives (sphere, box, capsule, plane, heightfield, convex shape, triangular mesh)
* Various joints types (spherical, revolute, prismatic, cylinders, fixed, distance, pulley, 6DOF)
* Advanced ragdoll, with joints, creation and editing
* Materials and friction model in support of surface collision behavior
* Continuous Collision Detection support for fast moving objects
* Raycast, sweep, trigger, and overlap test collision detection
* Collision groups + Collision Filtering – enable/disable collision detection
* One-way interactions (Body ‘X’ can effect body ‘Y’ but not vice-versa)
* Contact report allowing developers to trigger both alternate actions when specific objects interact or modify behavior of various contacts

http://developer.nvidia.com/object/physx_features.html

 

[Mussels]

They are not using two engines. Where have you seen that PhysX has no collision? That's BS, it HAS. It's in the features list and everything.



http://developer.nvidia.com/object/physx_features.html

you're ignoring what i'm saying.

I'm saying Physx items cant collide with things outside the physx engine - which means they either code two engines (one for Nv physx on and one for off) or they do a hybrid between the two (to make it lower requirements/workable in software)

They arent making 100% of the game world ported entirely the physx, or the damn thing wouldnt run without hardware acceleration!

 

[DarkMatter]

you're ignoring what i'm saying.

I'm saying Physx items cant collide with things outside the physx engine - which means they either code two engines (one for Nv physx on and one for off) or they do a hybrid between the two (to make it lower requirements/workable in software)

They arent making 100% of the game world ported entirely the physx, or the damn thing wouldnt run without hardware acceleration!

And you are not paying attention to anything that I have said in the thread. PhysX DOESN'T REQUIRE hardware at all. It can run in software mode...

 

[Mussels]

And you are not paying attention to anything that I have said in the thread. PhysX DOESN'T REQUIRE hardware at all. It can run in software mode...

i've done that. it runs like crap. even an OC'd Q6600 cant handle it without massive FPS decrease, so its useless on most systems.

 

[btarunr]

i've done that. it runs like crap. even an OC'd Q6600 cant handle it without massive FPS decrease, so its useless on most systems.

My Phenom 9750 seemed pretty comfortable with PhysX Screensaver with 25% particle density.

 

[DarkMatter]

i've done that. it runs like crap. even an OC'd Q6600 cant handle it without massive FPS decrease, so its useless on most systems.

It doesn't run like crap. At all. IF and only if you enable the PhysX checkbox in Mirror's Edge and disable PhysX in the CP, of course it lags. But that's all about GPU PhysX. CPUs can't handle that kind of massive physics.

 

[TheMailMan78]

My Phenom 9750 seemed pretty comfortable with PhysX Screensaver with 25% particle density.

Link to this said screensaver?

 

[Mussels]

It doesn't run like crap. At all. IF and only if you enable the PhysX checkbox in Mirror's Edge and disable PhysX in the CP, of course it lags. But that's all about GPU PhysX. CPUs can't handle that kind of massive physics.

so... you're saying its ok because it runs on a CPU, then your next post saying it doesnt work cause CPU's cant do it? thats... what i said.


How about we just agree to disagree? we're rehashing at this point.

 

[DarkMatter]

so... you're saying its ok because it runs on a CPU, then your next post saying it doesnt work cause CPU's cant do it? thats... what i said.


How about we just agree to disagree? we're rehashing at this point.

Let's see. You don't have to code or have two different engines. The CPU can't handle the massive physics that a GPU can do, so when running in software mode those objects (i.e cloth) are declared as non-physx-enabled objects and that's all. In Mirror's cloth items are replaced with animated flags, and some others just disapear from the game.

BTW, I have just tried disabling PhysX in the CP and running ME with PhysX enabled and it runs perfectly in my Quad, maybe a little bit lower FPSs but that's all.
EDIT: It does lag badly when glass is shot down.

 

[btarunr]

Link to this said screensaver?

Part of the NVIDIA Powerpack. Find it on NVIDIA's website.

 

[Lazzer408]

Here we go again. They been talking Havok since the 1xxx series. I bet Duke Nukem Forever supports it.

 

[DarkMatter]

Here we go again. They been talking Havok since the 1xxx series. I bet Duke Nukem Forever supports it.

PhysX has more chances of being DNF's physics API. It started by using Meqon physics, which was aquired by Ageia so...

@Mussels

Maybe you understand the thing better this way:

The only difference between PhysX hardware enabled and software mode is in the number of enabled objects. It can be directly compared to how the different graphics settings work.

 

[Lazzer408]

It was intended as a joke.

 

[DarkMatter]

It was intended as a joke.

I know. Sorry.

 

[kumquatsrus]

Cell Factor doesn't work on nvidia PhysX. I tried.. And I forgot Cryostasis, but it's really the ONLY game that uses it well.. I remember trying the demo and it was ok, but ran pretty bad on a gtx 280 and didn't really see anything cool besides the mercury, I mean water.

yes, cellfactor doesn't work on nvidia physx. however, cellfactor: revolution does indeed work on nvidia physx. i still play it right now from time to time on my 8800GT sli setup. i tried running the original cellfactor before, and an error message pops up stating that a ppu is not detected. so download the free game (cellfactor revolution, not cellfactor) and check it out for yourself. it should work.

 

[ShadowFold]

Well I don't have my 280(and don't plan on going back..) anymore, but I'm pretty sure I had revolution.

 

[Hayder_Master]

yeeeeeeeeeeeehaaaaaaaaaaaaaa, at last physics from ATI , and i my gift to nvidia is a song from AKON ( SMACK THAT ) .
from me i was think about swap my 4870 with 4870x2 and pick an nvidia card for physics but now time to crossfire my 4870

 

[Hayder_Master]

Yay. another reason to justify me getting my 4870.

you are dumm lucky man mussels , why you don't pick 4870 from the begging