How current games and systems render a scene

Consider a theoretical game scene of a box about to explode. The scene also contains a building and a person fleeing the frame. All this data is passed on from the game engine to the CPU for processing. Currently, the CPU keeps all data that requires physics processing. Once the CPU is done with these, it only passes all the graphics computations to the graphics card (aka GPU), which then renders the new position of the object and then outputs the final image or frame

The GPU takes all the graphics data nad renders the scene. However, it is often bottlenecked by a comparatively slower CPU, mainly due to the load placed on the CPU because of the physics and AI calculations. The end-result is a scene that has unrealisitic explosions and physiscs. We cannot expect any more, because CPUs, by design need to be more general purpose, unlike a GPU, which is built solely to process graphics.

How Upcoming Games and PPU-Enabled Systems will Compute and Render a Scene

Consider the same scene being played out in a system that has a CPU, PPU and a GPU. As usual, data from the game is passed on to the CPU, which then sends all graphics computation by itself. However, it now has the help of the PPU (Physics Processing Unit) to perform complex physics calculations for it.

The CPU breaks up the data into it respective parts and sends each processing unit its tasks; it computes AI and then passes physics data to the PPU and graphics computation to GPU for rendering.

Since the PPU is specifically designed to do physics calculations, it can do a much larger number of calculations in a lot less time than the CPU. In current designs, the PPU will receive data for physics processing from the CPU, but if a game is designed to directly interface with PPU driver or software, it may bypass the CPU entirely and this will lead to an even further reduction in the milliseconds of lag that we currently see.

The PPU then calculates the physics and send it to the GPU. The GPU renders the graphics, and then receives AI and physics data from the CPU and PPU respectively - and then renders the whole frame.

Because of the PPU's enhanced physics computations, the blast look more realistic. The same will apply to all in-game fluid dynamics and collisions.

 

 

 

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Sounds both interesting and feasable. However, I have one question. Is this a possible idea to be made realistic, or rather something that is already being produced. I am unclear as to where you are leading this.

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There is already a company that has a physics processing card either created or on the market. The demo's of the card in action are pretty impressive, they have decent graphics but HUGE piles of shrapnel, debris, people, etc being thrown around properly by explosions without any of the stress being put on the processors.

I can see these becomming more common over the next year, probably with some big announcements at E3. Just increasing the horsepower and adding more cores to GPU and CPU's won't be sufficient, they need to start thinking of alternative steps to take if they plan to continue advancing games at the current rate. I'm really excited about the physics card technology if it gets implemented properly.

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Yes, it's is indeed a feasible and interesting idea.

Not only it will take off some strain from the CPU, but it will also (hopefully) allow to compute more realistic physics. As good as they are today, the DO need a lot of work.

By adding one of those cards, developers can start working on physics with less restrictions.

Also, having dedicated hardware for it may mean you can calculate something that would usually take a lot of maths from your part using only a call to the hardware driver with a few parameters, since it can be done at hardware level.

I hope we see some development in this department soon.

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Does it really make a large difference having a PPU if you have a fast CPU? I'm sure a PPU will help performance wise some, but will it act any different?
I was thinking about putting a PPU in my next system just for the hell of it though, but does anyone recommend one?

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I wouldn't invest on a PPU-enabled card any time soon. It's a bit like dual processors, software has to be coded explicitly to take full advantage of it, and most games are still fully coded to work at full throttle on "regular" machines.

Someday, yeah, it'll catch up but until then, I'm saving a couple of bucks.

And having a PPU will not only give better performance but will also allow for more realistic effects since it can do more complex calculations in the same time because it's not worried with anything else.

 

 

 

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Instead of opting for a PPU, wouldn't adding an additional processor be more helpful? That wouldn't then restrict the PPU's usage to only games/apps which require PPU support. What about the newer Dual-Core chips? Will they still fall short of dedicated PPUs?

Also, as a theoretical device this is all well and good, but what will it do for the increased power consumption? Any additional device will always consume more energy and dissipate heat. Are we ready for all this?

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You mean the Ageia processor with PhysX? Check out the demo videos they look too good to be true. Just like what amitbhandari says, huge amounts of debris and shrapnel flying about all over the place, but the processor manages it seamlessly.

But the problem obviously arises when you actually have to write games so that they make use of the PPU. Just like the dual core technology, if the program isn't designed to use 2 processors simultaneously, then we'll have one processor doing all the work and the other one sitting idle all the time while the program is running.

Check out the videos at: http://www.ageia.com/physx_in_action/footage.html

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Isn't the implementation of they PhysX card atm rather shoddy though? As I recall, Ghost Recon Advanced Warfighter experienced a drop in frame rate whenever there were explosions with the PhysX card as compared to without it.

Considering that the PPU card is supposed to do these calculations, I don't see why it should see a drop in frame rate. The debris shots that I have seen looked rather ridiculous and unrealistic as well not to mention that they disappeared really quickly.

Considering the price of the card and since it doesn't really add performance except add a couple of sprinklies, I don't think physics cards just right now are worth it though some of the other demos that use the card in novel ways are interesting (though they still suffered lacklustre performance).

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Haven't heard about that, but this is still new technology. It needs time to sink in. Of course, we can still play high end games with excellent Framerate and resolution with a good graphics card, but with the increasing demand of more and more realistic games, I believe the only way out is to have a PPU which will perform these things much more efficiently than a regular processor.

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