Digital Foundry Article Technical Discussion Archive [2010]

[N_B]

The SPU are the way.

As he said, they're already being used to help with that.

 

[Yashamaru]

As he said, they're already being used to help with that.

So if i've read correctly his message he stated that the 360 is more powerfull than the PS3 It's sound strange because the cod game are particulary worse on the gfx side with poor shadow and poor texture resolution.
Justify a poor job isn't an explanation of the gap between the two version

 

[Shifty Geezer]

We're not going to enter into a silly, fanboy fuelled console fight here. "Which console is more powerful," isn't welcome. COD:BO is what it is on these platforms, and we can discuss this game. What should have been, because such-and-such a console is the Golden Child of entertainment and can produce quality much better than that other riff-raff urchin of a machine, is not a technical discussion nor in the spirit of B3D. We even have a special guest star contributor in Barbarian! You have a chance to ask a dev about how they went about amking these games and what struggles they faced, which is far more interesting then "this platform has better exclusives than that platform so nyah nyah nyah."

 

[Laa-Yosh]

Thanks Shifty, it's been well past time...

 

[AlNom]

It's also interesting to note that in BO the shadow filtering is worse on PS3, when for MW2 it was the other way round.

From what I've seen, it's simply that the shadow technique wasn't changed from MW2 on PS3 (maybe self shadows did?). On 360 BO, it seems they were able to afford an increase in shadowmap resolution (consider memory, z-fill etc). With regards to filtering, they'd still have to do the four texture fetches (4 samples) so adding a few math ops to smooth them out shouldn't be too bad (in MW2, it looked like just different offsets with no interpolation between the samples).

 

[Laa-Yosh]

By the way, I'd be interested in how complex the shaders can be for a 60fps game. I know a lot of the looks is about carefully tuning the detail in the normal and specular maps and the properties of the specular highlight, but what kind of other complexity is there?

 

[ultragpu]

I understand Barbarian has pointed out how heavily those SPUs have been used but one thing I would like to know is how efficient the SPU codes are in BO? If the game is been developed on PS3 as an exclusive will the result be any different?

 

[Ruskie]

Been playing 360 version for a while but my stupid 360 just got broke...warranty-gone but what i have to say is,when stupid 360 runs it game really runs great,it averages what, 55-56fps while looking really exceptional.Anyway,Barbarian,i just wanted to say that i was very impressed with characters skin and animations,and some great depth of field when for example doing breach.It had some depth feel to it...3dish look.Wondering how did you get it to look so good at 60fps,some games have rather cheap looking one at barely 30fps.What is the cost in ms?:smile:

 

[scently]

Been playing 360 version for a while but my stupid 360 just got broke...warranty-gone but what i have to say is,when stupid 360 runs it game really runs great,it averages what, 55-56fps while looking really exceptional.Anyway,Barbarian,i just wanted to say that i was very impressed with characters skin and animations,and some great depth of field when for example doing breach.It had some depth feel to it...3dish look.Wondering how did you get it to look so good at 60fps,some games have rather cheap looking one at barely 30fps.What is the cost in ms?:smile:

Indeed, the opening cut scene at the Bay of Pigs really impressed me.

 

[scently]

I'm sorry, but your information is just not correct. IW did have access to W@W, but I don't think they cared.
These games are developed over 2 year periods. By the time the other studio is out you are half way through development, IW's engine is quite massive and convoluted. You can't just go grab bunch of code and expect it to work.
For good or bad, the engines have drifted apart, mostly because IW worked in full secrecy and isolation.

Obviously I might be biased in this case, but I personally don't think BO is a step back from MW2.
Everyone has their opinions, and especially when it comes to "looks" I don't know how we can possibly be objective about it. I think BO has fantastic lighting, character work and weapons.

I just want to congratulate you guys, the game looks really good. Better than MW2 IMO, and that was a game that was among my best looking games of 2009.

 

[Shifty Geezer]

If the game is been developed on PS3 as an exclusive will the result be any different?

Inevitably, assuming a suitable talent pool that can make the most of the system, and suitable funding. That's no different to a tailor made suit fitting better than an off-the-peg one.

 

[kagemaru]

thanks again for the insight.

are you allowed to talk about "some" specifics?
for instance on Xbox360: did you use the EDRAM in specific unusual ways to increase performance?

Judging by what we do know, it looks like they aren't really using the EDRAM in any unusual way.

Well my memory is starting to get hazy, been out of the game for a while now But from what I recall msaa on ps3 is affected by both poly count and bandwidth. If I remember right the previous cod game on ps3 hovered between 40 and 60 fps. For you guys, doubling everything up for 3d maybe maybe would have meant 20 to 30fps. 40fps is playable in 2d mode, but 20fps in 3d mode is borderline...so I was thinking maybe to compensate they lowered the poly count of everything and dropped the res to make 3d mode doable. PS3's msaa has a per primitive cost, so every msaa'd poly you draw adds overhead, so less poly's means faster msaa performance. The msaa resolve step is also time consuming on ps3, but with your guys lower res buffer that might have helped it along as well. So it's a guess on my part...but I was thinking that maybe using lower poly assets and a lower res buffer is what made msaa (and 3d) playable for you guys on ps3. For the render targets, they matter if you over saturate one bus. Like if you do everything in vram them the vram bus is getting heavily worked while the dram bus could be snoozing, so you have to split all those work loads across both pools of memory to share the load. Lower res on ps3 will also make it less likely that bus saturation would happen.

But like I said, just a guess...I haven't played the new cod just yet. Although that Pentagon lady does look quite fine I will be getting the game eventually, I love the cod series.

If your guess is right, why not opt for the lower resolution only when 3D is enabled instead of all the time?

I just want to congratulate you guys, the game looks really good. Better than MW2 IMO, and that was a game that was among my best looking games of 2009.

I agree, I'll admit that I'm not the biggest CoD nut, I've still played and enjoyed them all. MW2 blew me away graphically and Black Ops looks even better IMO. The team should be proud

 

[SG79]

So if i've read correctly his message he stated that the 360 is more powerfull than the PS3

That's now what he said though. All he said that the 360 was used in a way that the PS3 couldn't go, which could mean a number of things (he's mentioned memory for one). Exploiting a strength if you will.

 

[TheDoomsdayMonster]

@Barbarian

You say that fitting the ps3 version of BO into memory was an issue, yet you guys neglected to use a form of AA (MLAA obviously) that would have saved you around 18 MB of RAM? Inaddition to saving RAM and Fill Rate, MLAA would have freed up more GPU cycles which could have been used to produce a high frame rate...

No dispect, but using MSAA over MLAA that doesnt make sense given the issues with the ps3's frame rate and memory...unless you are implying that MLAA was not possible because of a lack of left over SPU cycles?

 

[dragonelite]

@Barbarian

You say that fitting the ps3 version of BO into memory was an issue, yet you guys neglected to use a form of AA (MLAA obviously) that would have saved you around 18 MB of RAM? Inaddition to saving RAM and Fill Rate, MLAA would have freed up more GPU cycles which could have been used to produce a high frame rate...

No dispect, but using MSAA over MLAA that doesnt make sense given the issues with the ps3's frame rate and memory...unless you are implying that MLAA was not possible because of a lack of left over SPU cycles?

Yeah he said the spu are used quiet well, so probably not enough cycles over to do Mlaa.

 

[nightshade]

well he did mention that they barely gained anything by disabling MSAA (but how's that even possible ? it effectively means that the MSAA hit was minimal)

Well, of course we considered it. I'm a big MLAA proponent as you might know, However we found negligible gains from turning MSAA off. I know GOW reported massive savings - the only way I can explain the discrepancy is that GOW runs at 720p and maybe it matters more at that resolution.

 

[TheDoomsdayMonster]

Well, as pertains there not being enough cycles leftover on the SPU's, I have a hard time believing that BO uses them more thoroghly than some of Sony's standout 1st party efforts like Killzone 2 (which theorectically could have easily used MLAA had the technique been available for them at that point in time)...

As pertains the BO team not saving much performance by not turning MSAA off, doesnt MSAA require 6ms of GPU time as well making a dent on RAM usage and fill rate? Sorry...but that and not saving much performance doesnt add up.

 

[Neb]

well he did mention that they barely gained anything by disabling MSAA (but how's that even possible ? it effectively means that the MSAA hit was minimal)

It might then mean that Cell is the bottleneck in that situation. Or maybe GPU MSAA logic and bandwidth not being taxed much at 544p res. Just speculation though.

@Barbarian

Is the PC version (on max settings) rendering alphas at sabe res as framebuffer or scale with screen resolution while being lower res or a combo. Also if it scales, does it have a limit (thinking about how triple screen gaming would be affected)?

Some thoughts about games I've had since observing how some games have fixed PP/alpha res while other games have it scales in relation to screen resolution and some games do PP/alphas at framebuffer res. Metro 2033 for example on very high setting does alphas/post-processing at same as framebuffer res and AFAIK atleast upto 2560x1600 res.

 

[Barbarian]

Guys, I'll try to answer questions, but please do understand I can't go into certain specifics. I hate to be vague, but anything I say, might be pulled out of context and tweeted across the globe and have all kinds of unpleasant consequences for me.

There's very little publicly known about the IW/Treyarch's engines, which is a shame, since there are some rather brilliant things about it (and massive amounts of legacy too).
I'll try to get permission on what I can I can't talk about it.
Until then, it's fair to say that there's very little that hasn't been squeezed out. No low hanging fruit as they say. It's one of very few engines that targets 60 fps, and that puts incredible restrictions on the kind of methods/techniques one can use. A lot of the deferred lighting, motion blurs, and other high end sexy effects that KZ and Uncharted do are only possible because they have double the GPU budget to play with (not to mention tons of SPU time to help out as well, which adds a 3rd frame of latency!!!).

 

[Ruskie]

Well, as pertains there not being enough cycles leftover on the SPU's, I have a hard time believing that BO uses them more thoroghly than some of Sony's standout 1st party efforts like Killzone 2 (which theorectically could have easily used MLAA had the technique been available for them at that point in time)...

As pertains the BO team not saving much performance by not turning MSAA off, doesnt MSAA require 6ms of GPU time as well making a dent on RAM usage and fill rate? Sorry...but that and not saving much performance doesnt add up.

While thats true about KZ2 usage of spus i think GG said that in MP, spus workload goes up so they left some unused(at least i think i read it here at b3d).Also,it seems that GG implanted MLAA in KZ3 but they dropped OMB that they had in KZ2 and MP performance with alot of a.i on screen are not really smooth,it can go down to 20fps.Call Of Duty BO on the other hand runs at 60 fps and i dont know if you played it but that game is pretty chaotic while great looking indeed.Lots and lots of a.is on screen at once,lots of explosions all around you and lighting and shadowing can be pretty superb at times.I just played snow level in sp campaign and i have to say that thats possibly best thing i saw running on 360,amazing looking.Especially characters(skin),wet shader on cloth can look pretty nice to.To bad barbarian probably wont be here anytime soon since his posts are used for some articles of different subject.

On MSAA thing i think Joker here explained(barbarian said it to).Cost on ps3 varies from game to game.

http://forum.beyond3d.com/showpost.php?p=1492722&postcount=846

Edit.ups, here He is