A scientific experiment - Cell does T&L, with MAG

[3D_world]

Greetings everyone. I know many of you are inclined to not believe my inside source - but it has told me, that as a scientific experiment, the Playstation 3 game MAG: Massive Action Game, is employing the Cell processor to do all the Transform and Lighting for the game.

It sort of looks like the source is right, doesn't it? The style of the game - it is different from other games which use GPUs to do Transform and Lighting.

Now what have we learned from this game, about the Cell processor? Given the fact that the game can support 256 online players, that's certainly a technical achievement. Call of Duty 4 supports 16. No other game does 256 online player. But the maps are not that detailed. The game looks like a Quake III era game.

Thus, Cell is not not that good at floating-point ops. 7 SPEs, but with a severely hampered memory bus. Token-ring. No load-store units or branch units. Meaning it stalls on IF and other conditionals. 1 128-bit SIMD unit and 1 double precision floating point unit per core for SIMD, 256 Kbytes of SRAM cache. What is good at floating-point ops? The Power7 architecture. 4 MB of eDRAM cache per core, 1 Altivec/Velocity Engine/VSX 128-bit floating point unit, 4 double precision floating points units, load-store units, a branch unit, etc.

 

[3dcgi]

Even if your source is correct about this game it doesn't prove anything about Cell. Cell is very good at geometry calculations.

 

[3D_world]

Okay after seeing the game in action, I can say it is certainly way more advanced then a Quake 3-era game. What can we gain from this scientific experiment? The following:

1. It is possible to use the CPU to do Transform and Lighting, and creating a very advanced game, in the current generation.

Reason - there are 7 128-bit SIMD units, and 25.6 GB/s of memory bandwidth to power the CPU. Thus very capable.

2. Games which use the CPU to do T&L can support many more players - this one has 256 online human players - the most for any FPS.

Likely reason - the CPU has large caches. It can store the character model vertices on the 2 MB of CPU cache easily. For a GPU - the often-repeated vertex models - 256 models, perhaps 10,000 vertices each, all have to be transferred from the memory each second. On the CPU - you can store the 10,000 polygon base model on cache - which will only take up 240 Kbytes - 1/10th of the total cache.
Thus due to the onboard cache, the CPU is far more efficient at data structures and sorting algorithms. I.e. the often-used data structure - the character model - is simply stored on cache. The GPU has no such stable cache.

 

[3D_world]

Even if your source is correct about this game it doesn't prove anything about Cell. Cell is very good at geometry calculations.

I guess it's exactly as good as can be expected from a CPU with those specifications.

 

[BRiT]

scientific experiment

scientific experiment

You keep on using that word. I do not think it means what you think it means.

 

[3dcgi]

I doubt performing all T&L on the CPU has anything to do with supporting more players. Most games perform collision detection on the CPU already and some PS3 games even rasterize a low resolution version of the scene using Cell which means they perform T&L on it.

 

[Grall]

The OP swings from one far end of the spectrum - Cell is not very good at geometry calculations - to the exact opposite - Cell is very good at geometry calculations - all in the span of two consequtive posts, and using the same dataset (one single game, in this particular case.)

...Some "scientific" experiment this is.

 

[Shifty Geezer]

How on earth do you determine from a screenshot if the TnL is happening on the CPU or GPU?

 

[Mize]

How on earth do you determine from a screenshot if the TnL is happening on the CPU or GPU?

You don't know? CPUs use more traditional, halogen lamps to perform the lighting while GPUs use more efficient LEDs. This results in a slightly "warmer" lighting effect when CPUs do the T&L.

 

[Nesh]

Regardless of Cell, what is amazing about this is the 256 player count. How did they achieve that?

 

[Shifty Geezer]

Regardless of Cell, what is amazing about this is the 256 player count. How did they achieve that?

Efficient coding, LOD, and maps that don't put all 256 players on screen. When there are that many players together, I imagine the framerate crawls, but I've never seen footage or gameplay that puts more than a dozen or two soldiers in view at a time (including some very distant). And if you're not displaying more than the equivalent of 32 players in a COD map, the technical requirements shouldn't be much more. There isn't a magic amount of triangles in a scene in MAG, and there's no need for super special TnL from what I can see. If they did experiment with using Cell instead of the vertex shaders on RSX, which could have a nice nap being wasted silicon in such a scenario, it doesn't obviously accomplish anything.

 

[Grall]

FPS shouldn't neccessarily crawl, even such an early game as that Rare title whatsitscalled had scenes with tens of thousands of animated characters on-screen. Sure, they were tiny so most probably very simple, but this was a long long time ago now (in computer industry years), so with proper coding a comparatively piddly 250 characters shouldn't be a supreme deal on the rendering front as long as there isn't significant overdraw in the 3D engine. If that's the case you could knock your head on the rather low fillrate ceiling of the PS3 of course, but there are many other situations where that is possible, so not really a hindrance for having many players in a game.

The biggest limitation would rather be internet connection bandwidth and server capacity methinks. I assume these games aren't hosted on a PS3, because that many players would easily cap out most peoples' upstream bandwidth. Heck it might well cap out many peoples' downstream connection too... Especially if running on some kind of cellular connection, although considering the often obnoxiously high latency 3G/edge gets I don't know why anyone would want to do that... Heh.

Btw Mize... LOL!

That's a far more scientifically accurate analysis than the OP's, methinks!

 

[Lucid_Dreamer]

Efficient coding, LOD, and maps that don't put all 256 players on screen. When there are that many players together, I imagine the framerate crawls, but I've never seen footage or gameplay that puts more than a dozen or two soldiers in view at a time (including some very distant). And if you're not displaying more than the equivalent of 32 players in a COD map, the technical requirements shouldn't be much more. There isn't a magic amount of triangles in a scene in MAG, and there's no need for super special TnL from what I can see. If they did experiment with using Cell instead of the vertex shaders on RSX, which could have a nice nap being wasted silicon in such a scenario, it doesn't obviously accomplish anything.

Patsu use to talk about this all the time, in the MAG thread. Here is 128 players on screen at one time. It was smooth.

http://beyond3d.com/showpost.php?p=1389190&postcount=603

 

[kagemaru]

It's threads like this that make me double check the address bar to make sure I didn't accidentally load up a Gamefaqs forum.

Patsu use to talk about this all the time, in the MAG thread. Here is 128 players on screen at one time. It was smooth.

http://beyond3d.com/showpost.php?p=1389190&postcount=603

There may be 128 players in that general area, but in no part of that video are there 128 on the screen at one time, or even close. Also unless the game was updated since the last time I played it, it was anything but smooth when the action got heavy.

 

[Gitaroo]

does DUST 514 runs well on PS3? What's the player counts on that.

 

[Mize]

Btw Mize... LOL!
That's a far more scientifically accurate analysis than the OP's, methinks!

I was starting to think nobody noticed

 

[Lucid_Dreamer]

It's threads like this that make me double check the address bar to make sure I didn't accidentally load up a Gamefaqs forum.



There may be 128 players in that general area, but in no part of that video are there 128 on the screen at one time, or even close. Also unless the game was updated since the last time I played it, it was anything but smooth when the action got heavy. Maybe the Sony worshipping altar you have grants your PS3 super powers to render games flawlessly?

Doubting beyond reason, again. There have been group photos of all team members, on GAF. That means 128 players. Here is a better view of the same video. How many can you see at one time and what are they doing? Is it more than you have ever seen together, in a multiplayer game? If not, which one have you seen more in? Are they standing still or moving, shooting, and throwing smoke grenades? Did you notice framerate drops to a crawl?

www.youtube.com/watch?v=OxzjEkQEJ-s

http://www.giantbomb.com/forums/general-discussion/30/mag-128-players-on-screen-gameplay/386559/

 

[Gitaroo]

cant wait to see PS4 handling planet side 2 then.

 

[kagemaru]

Doubting beyond reason, again. There have been group photos of all team members, on GAF. That means 128 players. Here is a better view of the same video. How many can you see at one time and what are they doing? Is it more than you have ever seen together, in a multiplayer game? If not, which one have you seen more in? Are they standing still or moving, shooting, and throwing smoke grenades? Did you notice framerate drops to a crawl?

www.youtube.com/watch?v=OxzjEkQEJ-s

http://www.giantbomb.com/forums/general-discussion/30/mag-128-players-on-screen-gameplay/386559/

It's not a doubt and it's not beyond reason, I know what my eyes see and I know how to count. Any one of us can watch the video and see with our own eyes that there was no part where all 128 players were on the screen at once as you claim. Same could be said for the second video you posted. Not really sure what's so hard to understand.

Also, while I don't like to judge performance on streaming videos, it looked like there were plenty of frame drops in the video you just posted. I know for a fact the game itself had frame drops when I played it.

Not everyone can see frame drops, I've been told by a handful of people that the frame rate in Far Cry 3 is solid when it's anything but solid. So it's ok if you don't have an eye for it.

 

[Shifty Geezer]

Doubting beyond reason, again. There have been group photos of all team members, on GAF. That means 128 players. Here is a better view of the same video. How many can you see at one time and what are they doing?

You can hardly see anything. The ghosting is a mess, making it hard to work out how much is happening and how many are on screen on once and how complex the models are. It's certainly not smoothly animating. There's also just a moment at the beginning where there's clearly ~40 players on screen given health bars, but then they all spread out and you only see a dozen or two on screen at once. There's no measure of LOD or environment complexity versus other titles (you divided the vertex budget between characters and scenery, so if your game targets less than players, you can invest more in scenery and vice versa) so even having 40 characters at a time might not be seriously pushing polycounts.

Is it more than you have ever seen together, in a multiplayer game?

Being multiplayer is immaterial to the requirements of TnL unless you want to design your system to account for GAF coordinated parties. You design assets for a given quality, provide suitable LOD, and manage accordingly regardless of whether troops are positioned by AI or other people.

Here's a crowd vid for you:

OMG! Only the powerz of teh Cell can make this happen! Except it's a 2006 PC game, not only drawing and animating thousands of troops, but managing their AI too. Of course, that's because the GPU is handling the TnL leaving the CPU to calculate AI...

There's nothing remarkable about MAG's vertex throughput or graphics only made possible by the Cell, AFAICS. It'd make far more sense to use Cell to help with vertex culling prior to RSX TnL (players obscured by other players or scenery need not be drawn), using all the hardware available instead of having the vertex units idle.