Physics Processor - a technical question

[david.dakota]

Nintendo is rumoured to be including a physics processor into Revolution, which i think is a first in video gaming (at least with the Big Three). This is speculation from a variety sources.

Assuming Nintendo are including a physics processor, what 'jobs' will this processor do? Manage the explosions of a crate? Bullet holes in the wall? These all seem quite graphics orientated to me...

Also, with the current machines, how much processing power is used to create whatever constitutes as 'physics' in a game?

[El_Fuego_Fuerte]

Basically, it's mainly for when things are being knocked around. So, for example, in a game I shoot a crate, and it falls down. That's the physics engine at work. Obviously, it gets a lot more complex than falling crates...a good example being the Half-Life 2 physics engine.

[Pestneb]

basically the PPU chip would have operations built into it that are solely related to physics calculations.
its a bit like saying GPU's could just be done by CPU's, now there are more complex operations, so there's a whole chip dedicated to doing graphics.
although this is as plausible as an AI processor.

[Kurtle Squad]

So why haven't they been used in home consoles before!??! :confused:
Surely they make things seem less gamey!!

[Sooj]

So why haven't they been used in home consoles before!??! :confused:

Mainly because it is/was too expensive.

[Konfucius]

Right, for PC such a card (with 128 MB RAM) costs around 250 to 300$ according to PPU manufacturer AGEIA.

Source: Gamestar.de (http://www.gamestar.de/news/hardware/28527/)

[Kurtle Squad]

Oh right!! Well that's just computer companies ripping people off!

[system_error]

Well now lets say Nintendo wants a PPU - single chip with some embedded RAM and the price goes down into affordable regions. The problem is that games do not automatically gain performance or "real physics" just because there is a chip. It would mean that Nintendo needs a strategic alliance with AGEIA to deliever a reliable and easy SDK for the developers. So far I know only Sony offers AGEIA Middleware (here the Cell architecture does the work not a PPU) - so I guess that Nintendo will not have a PPU.


A PPU is just a chip speeding up calculations which are need for physical information processing. It is nothing special - it is just something nobody needed before. I don't know how complex the AGEIA PPU is but its possibilities range from calculating tin cans way down when you shoot them to movement and deformation of characters. Basicly it could help a CPU out in many ways - you could even use it for non-physic things since some hardware commands might be actually helpfull in other regions of coding. I think a PPU might be a good way too increase overall performance for the Revolution because the CPU could be slower (less MHz) which results in a lower heat output and maybe even a smaller price depending on how expensive the PPU would be.

[Hal_9Million]

The laws of physics in a game are a bit like the laws of physics in the real world. In the real world, the laws of gravity keep you on the ground. In a computer game, grogrammers can decide what amount of gravity there is going to be It can be realistic, or crazy low grav. This is physics in it's simplest form (I think). If I'm not mistaken, a physics engine is designed to allow you to interact with the game. Half-Life 2 is a great example. There is a large amount of interaction with character and objects, and this is handled by the physics engine. Curretnly physics engines are incorporated into the graphics engine. The graphics are handled by the GPU, and therefor there is only so much allowed for a physics engine. By having a PPU, you have a new seperate processor dedicated to physics. Now the GPU can handle purely the graphics, and the seperate PPU can organise the physics. I beleive that physics is the real way forward in games after graphics and it's going to become ever more important. With the new Revolution controller, a PPU could mkae the interaction with the game much more detailed. Lets look at an FPS for example. Currently in these games, you shoot someone, they fall to the ground (physics). You can pick up their gun and fire, and it's going to have a different affect to another (physics). What can you destroy with a gun? Well in most cases other characters. You can make bullet holes, and there is of course the game favorite of destroyable crates, and exploding barrels. For most games that is about it. You do however get the occasional destroyable piece of scenery, but it's quite basic. Physics in the next generations to come should get better and better. Allowing you to blow a hole in any wall you like. Destory a pillar and watch a building fall on you opponent. Of course this can be applied in many differnent games in different ways. I'm not sure but a physics engine may also be able to control things like the number of characters on screen (correct me if I'm wrong) The PPU, if true, is going to give the Revolution an edge on the competition, I think. As neither of the competitors has one, they may not be able to achieve the same physical feats so easily, if at all. To my knowledge this is what a physics is, and what the ppu could do, though I'm pretty sure I'm 80% right. (If anyone has a greater knowledge, please correct my statements)

[Schpickles]

The laws of physics in a game are a bit like the laws of physics in the real world. In the real world, the laws of gravity keep you on the ground. In a computer game, grogrammers can decide what amount of gravity there is going to be It can be realistic, or crazy low grav. This is physics in it's simplest form (I think). If I'm not mistaken, a physics engine is designed to allow you to interact with the game. Half-Life 2 is a great example. There is a large amount of interaction with character and objects, and this is handled by the physics engine. Curretnly physics engines are incorporated into the graphics engine. The graphics are handled by the GPU, and therefor there is only so much allowed for a physics engine. By having a PPU, you have a new seperate processor dedicated to physics. Now the GPU can handle purely the graphics, and the seperate PPU can organise the physics. I beleive that physics is the real way forward in games after graphics and it's going to become ever more important. With the new Revolution controller, a PPU could mkae the interaction with the game much more detailed. Lets look at an FPS for example. Currently in these games, you shoot someone, they fall to the ground (physics). You can pick up their gun and fire, and it's going to have a different affect to another (physics). What can you destroy with a gun? Well in most cases other characters. You can make bullet holes, and there is of course the game favorite of destroyable crates, and exploding barrels. For most games that is about it. You do however get the occasional destroyable piece of scenery, but it's quite basic. Physics in the next generations to come should get better and better. Allowing you to blow a hole in any wall you like. Destory a pillar and watch a building fall on you opponent. Of course this can be applied in many differnent games in different ways. I'm not sure but a physics engine may also be able to control things like the number of characters on screen (correct me if I'm wrong) The PPU, if true, is going to give the Revolution an edge on the competition, I think. As neither of the competitors has one, they may not be able to achieve the same physical feats so easily, if at all. To my knowledge this is what a physics is, and what the ppu could do, though I'm pretty sure I'm 80% right. (If anyone has a greater knowledge, please correct my statements)

You're getting a little carried away there. Like graphics cards, PPUs basically are designed around the calculations required for physics collisions. In the case of graphics cards it's doing calculations such as matrix transforms and rotations which are very maths heavy on a general purpose CPU (i.e. takes several clock cycles) and doing them in very few (sometimes even 1) clock cycle, by using specially wired hardware designed specifically for those types of calculations.

Physics is very similar in terms of having a lot of calculations, and only in recent years have physics simulations become complex enough to warrent having a seperate chip.

Physics calculations is much less about "setting gravity" - that's the sort of thing that you can tweak after a physics simulation is working. The grunt work of physics is working out where objects are colliding or intersecting with each other, working out reaction forces for all of those points, and working out forces acting on joints, pivots etc etc.

If you'd like a (pretty technical) look at what a physics engine entails, have a look at the Open Dynamics Engine at http://www.ode.org/. It's not as cutting edge as the simulations like Novodex and Ageia offer, but it does at least show you the kind of things that physics engines do. I'm using ODE on a project im working on at home, and STALKER based its physics engine on it.

The reason phsyics simulation is now well suited to having a dedicated chip is that there are a hell of a lot of very similar types of calculation going on. GPUs and PPUs would be very badly suited to running an application on - they are designed to do a fixed type of instruction very quickly, lots of times in succession. GPUs started this with very fixed functionality (i.e. the common transform [rotation / repositioning] of vertices and lighting of traingles) and then has grown to shader languages, where the programmer is free to write the small loops of code that are executed over and over and over on a whole bunch of data.

PPUs will provide the grunt work for doing a whole bunch of physics calculations, such as collision, reaction etc. The CPU and main memory will still organise what goes where (as with graphics), but the grunt work of actually churning through the reams of data can now be offloaded, freeing the CPU to work on other things. No doubt by the end of this generation we'll be talking about the same for AI.

For Nintendo, if they aren't going to be packing a multi-core powerhouse CPU as most expect, a PPU would make sense because it would offload a great deal of work from the CPU. It is however unlikely to provide a performance boost over other consoles, who will be dedicating one or more hardware thread to physics simulation. This is actually more flexible as the CPU is general purpose, and the programmer can allocate work as they see fit.

However, at no point have Nintendo themselves indicated this will be the case. Morover, it seems that - like with the last generation - people have clutched wildly at PC specs, not understanding the nature (heat, power, form factor) and costing (3rd party = licensing fees & loss on manufacture & reliance on third parties for parts) of console hardware well themselves. I'd have though that it's more likely that Nintendo will include either a second G3 CPU (for emulating the GameCube and handling system operations) or including hardware dedicated to handling the controller input and translating it to the game world.

I think quite a few people on this board need to lower their expectations for the Nintendo hardware in revolution - it's really not going to be that powerful, because Nintendo can't afford it to be. I'm still guessing G4-equivalent CPU, 256Mb RAM and an evolution of the Flipper GPU... nothing more than that.

**EDIT**

Kudos to System_error's post which did a really good job of explaining this stuff.

Also - might be of interest - from the ODE site there was a link to this: http://www.ode.org/slides/slides.html which is a slideshow of "what is a physics SDK" for non-technical folks.

[DCK]

PPUs are great because they not only take A LOT of work of the CPU, but can do more. You would cripple the X360 CPU by simulating a field of grass waving in the wind, but a PPU could do this reasonably, without involving the CPU in the process.

@ Schpickles
Why do you think a G4 CPU? G5s shouldn't be more expensive and a lot more powerful...

[Cheapshot]

PPUs are great because they not only take A LOT of work of the CPU, but can do more. You would cripple the X360 CPU by simulating a field of grass waving in the wind, but a PPU could do this reasonably, without involving the CPU in the process.

Yeah, I think this is one of the ways how Nintendo are going to acheive PS3 quality visuals with a lower spec machine.

I think Nintendo should go for a PPU in the Revolution; how costly are they however?

[DCK]

Yeah, I think this is one of the ways how Nintendo are going to acheive PS3 quality visuals with a lower spec machine
I'm not sure if the PPU could just do that though ;) I was just giving examples but it should be much better at doing physics than any of the most powerful CPUs. I think it might even outperform Cell on physics works.

[Cheapshot]

I'm not sure if the PPU could just do that though ;) I was just giving examples but it should be much better at doing physics than any of the most powerful CPUs. I think it might even outperform Cell on physics works.

No I said it would be simply helpful to could acheive such visuals, I really want to see this new rendering method; it's got me interested. I think a PPU would be very useful for the very physics heavy games that the controller will probably bring with it's new level of interaction.

[system_error]

I think a PPU would cost Nintendo maybe 30-50$ per console depending on the complexity of the hardware and the amount of RAM.


I also have to disagree with Schpickles I think the PowerPC970FX is the more obvious choice because it offers more power and very low power consumation. That would perfectly match Nintendos small console. But I am not 100% sure since Revolution development started a long time ago and I don't think you can start developing a custom architecture for a "G4" and then simply switch to a "G5".

[DCK]

The G4 is getting out of date now. The GameCube Gekko is G4-based , it's been used in iMacs since 2000, and they've stopped using it since 2004. Their highest end system goes only to 1.42 GHz, only three times that of the Cube.

The Revolution's internal hardware design isn't finished (Retro Studios are getting update after update according to Matt Cassamina) so implementing a G5 is no problem, but they probably already have it in there.

@System_Error
I just backed you up here ;)

[system_error]

It seems you did not understand me. I am quite sure that IBM and Nintendo are working on a custom based PowerPC - and I doubt it is that easy to switch from PowerPC750CXe (that was the Gekko from the Cube) to a PowerPC970FX concerning the custom hardware architecture already made/planned/etc.

[Schpickles]

PPUs are great because they not only take A LOT of work of the CPU, but can do more. You would cripple the X360 CPU by simulating a field of grass waving in the wind, but a PPU could do this reasonably, without involving the CPU in the process.

@ Schpickles
Why do you think a G4 CPU? G5s shouldn't be more expensive and a lot more powerful...

relatively they still are a fair bit more expensive. It's easy to consider all of these parts on a single unit price, and not think in terms of how a manufacturer thinks... £1 per unit is a huge amount of money (£millions) when put up against the initial product run for a console. Think as well that with an upgraded CPU comes a more expensive motherboard aparatus more requirement on RAM busses, and in the G4->G5 case, the need for a more elaborate cooling system and probably a more potent power supply. Per unit this might not sound like an extortionate amount, but they all add up to massive amounts of money for a company the size of Nintendo.

Unlike their competitors, Nintendo like to keep close to the breakeven point on their hardware (often selling it at a profit, in fact), and they'll not want to do that with their new hardware. In their bitter "war for the livingroom", Sony and MS are prepared to take a heavy hit for the sake of the corporation, in order to lever Windows or Blu-Ray into your living room's box-under-the-telly. It's a bit different for Nintendo - they aren't making this product with other products in mind (save their other consoles and games) and therefore it makes less sense for them to take a cost hit on the console.

Back on topic the analogy of the "field of grass" just doesn't stand up - how do you know that a field of grass would floor the CELL or the PPC chip in the Xbox? For all you know, the PPU might be less well suited to it.

Personally, I think that with the cost, heat and form factor requirements (it only exists on a PCI card, currently), Nintendo are highly unlikely to put a PPU in the Revolution... but I wouldn't mind being proved wrong!

[Schpickles]

The G4 is getting out of date now. The GameCube Gekko is G4-based , it's been used in iMacs since 2000, and they've stopped using it since 2004. Their highest end system goes only to 1.42 GHz, only three times that of the Cube.

The Revolution's internal hardware design isn't finished (Retro Studios are getting update after update according to Matt Cassamina) so implementing a G5 is no problem, but they probably already have it in there.

@System_Error
I just backed you up here ;)

GameCube processor was G3 based, not G4 based.

mini macs, iBooks, Powerbooks all still use the G4 CPU. It's only the iMac and the PowerMac that are big enough to accomodate the G5, with its increased heat output.

[DCK]

OK, I was just trying to make a point with the field of grass :P

Anyway, yes the G5 will be a dash more expensive, but the G4 simply doesn't cut it for next gen. Consumers can only get so far as 1.42 GHz in an expensive PowerMac and Nintendo will have to pump it up to 2.5 GHz and/or use multiple cores if they even want to get within acceptable distance of the 360. The G4 wasn't made with those speeds in mind, nor does it do as well in multicore. The G5 is much better in terms of speed and multicore performance. Remember we're talking about mass-produced, customized chips that will only get in production next year. Microsoft has also mentioned their chances of making profit are much better with the new consoles, and they're using three high-end G5 cores. I think the G5 is much more suited for the Revolution.

[kav82]

Oh well, from what I've read I hope that Nintnedo does include a PPU in the Rev now!

[Ginger_Chris]

a PPU isnt really needed at the moment, the physics in games is extreemly simplified, even in say halflife 2, only certain things were moveable, and only in certain ways. Eventually they will be needed, just like graphics cards are needed now. But by then models will actuallt be made up of inidivual "atom" so they will break, shatter and morph realisticly. Itll need about 1000 "atoms" per object minimum, but will make things much more realistic. bullets actually leaving dents in walls as opposed to a leaving a bump mapped texture.

We'll need a PPU then, but now it would be a waste. Especially with none of the competition having it, it would be an unused feature in all cross platform titles, and underused in everything else. An AI procesor is similar, not needed now, but probably will in the future.

[gorrit]

Uhm, that "atoms" comment is just weird... Sure perhaps someday we will have realtime physics using "atoms", but you would need alot more then 1000 "atoms"(if I understand your technical view on these "atoms", and it seems to me that nice working hacks are far better and surely will be used for a long time to come.

We've just entered the gaming age that *will* need PPUs, very many next-gen titles have "advanced"(to be realtime) physics and would get an advantage with a PPU.
One big problem with PPUs tho, is that they are usually tied to a single physics API.

[Ginger_Chris]

I dont mean atoms in a physics sense, god no,(hence the air quotes) but its was the best word i could think of, say a brick in the game was 10 by 15 by 40 units. at each of the corners of each unit was a "atom" think of it more as point within the object. Each of these "atoms" was connected to the 6 adjactent atomes by a linearly flexible bond. If the bond was very flexible, when a virtual force was placed on the object it would apear to bend pretty realistically. If the bond were flexible, andthe force was strong enough then the bonds would shatter, and different bonds would shatter depending on where the force was applied. Thus creating very realistic shattering,bending and even water dynamics can be moddled accurately using this method. Its very processor intensive, and they'll be ways to opptomise it. Its just modeling the games in a very basic way our world is modled. with a PPU chip it would be much more feaseable. and yea, the more "atoms" the more realistic theobject behaves.