Killzone 2 technology discussion thread (renamed)

[Terarrim]

Be very intresting to see the pdf's that come out of GDC, i enjoyed the previous GDC GG PDF's very much.

Be intresting if they do have a percentage load of GPU work done by Cell (if this can be measured). Also as regards to they can push the PS3 even further than KZ2 I would guess this would also be mostly on the Cell side to, I.E. more use of the SPE's (higher than the 60 percent SPU usage for example, or better code giving increased performance after the KZ2 engine learning code, or even possibly a mixture of both.

I would imagine that after this game GG will have a very good idea exactly what they can expect from the Cell supporting the GPU any memory, bandwidth room they have to play with.

While Edge tells devs Cell utilisation, would be intresting from a deisgn perspective to see what bandwidth utilisation with the Internal Cell ring and flexi I/O processing graphical tasks for the GPU (in whatever form the Cell is doing GPU work).

I suppose what I'm getting at is have GG reached bandwidth limits using current SPU for GPU support or is there still plenty of overhead.

 

[TimothyFarrar]

What do you mean by heavy memory handicap? I thought it was only a few MB in favour of the 360 (due to the larger footprint of the PS3 OS).

Exactly, and separate memory pools only handicap those who choose not to use them wisely. A few MB of memory is not a bad trade off for 5x the storage capacity (BR vs DVD) for unique assets, or in the case of a studio not having the ability to fill the BR, having the capacity to duplicate assets to reduce seek time on stream in.

 

[Asher]

Exactly, and separate memory pools only handicap those who choose not to use them wisely. A few MB of memory is not a bad trade off for 5x the storage capacity (BR vs DVD) for unique assets, or in the case of a studio not having the ability to fill the BR, having the capacity to duplicate assets to reduce seek time on stream in.

You mention the storage capacity advantage, but not the storage transfer speed disadvantage associated with Bluray in the PS3? In any case, this is off-topic from the Killzone 2 tech discussion.

 

[joker454]

What do you mean by heavy memory handicap? I thought it was only a few MB in favour of the 360 (due to the larger footprint of the PS3 OS).

Yeah it's because of the memory Sony takes from us. It's significantly more than "a few mb" on our end though, and the more features you use, the more brutal the memory hit becomes.

 

[Statix]

You mention the storage capacity advantage, but not the storage transfer speed disadvantage associated with Bluray in the PS3? In any case, this is off-topic from the Killzone 2 tech discussion.

The optical read speed is at least offset by the universal presence of the harddrive, enabling virtual memory caching on a game-by-game basis. This effectively enables a total data transfer rate of the hard drive + the BD drive.

Yeah it's because of the memory Sony takes from us. It's significantly more than "a few mb" on our end though, and the more features you use, the more brutal the memory hit becomes.

I've heard that this OS overhead has been toned down and optimized significantly in the past year or so. Any truth to that?

 

[Shifty Geezer]

The known story behind the memory usage is that the default base OS level has been reduced, but there are overheads for including features, multiple megabytes to add Friends List support for example. This list of memory requirement made for painful reading, and adding basic functionality gobbled up RAM. Nothing has been heard on the matter since that first discussion though. I hope to Betsy Sony have made savings there, because the listed figures really were insane!

 

[joker454]

The optical read speed is at least offset by the universal presence of the harddrive, enabling virtual memory caching on a game-by-game basis. This effectively enables a total data transfer rate of the hard drive + the BD drive.

That's true although initially you can only load off the blu-ray when you first run the game so there is a speed hit there, unless you went with the mandatory install route. Many go with the mandatory install route because we can't hit Sony's required initial load time requirement with just the blu-ray drive.

More significantly though is that most of us will treat the hdd as optional and assume it's not there. This isn't due to any favoritism or conspiracy theories, but just business realities. Basically for many of us to stay alive, we desperately need to be able to work on the $199 console. Without that, the layoffs and company purges you are seeing happen would have been far more widespread. So as cool as the standard hdd may be, it will be used mostly in an optional manner.

I've heard that this OS overhead has been toned down and optimized significantly in the past year or so. Any truth to that?

Yeah they have steadily been improving it, default memory consumption is much better now than a year or so ago but they still lag behind. Likewise as Shifty says, there are 'optional' memory requirements as well, and those are still harsh.

Resistance 2 is doing this 4xMSAA trick as well as a second pass for even lower resolution particles.

Hmm...you sure R2 is doing it that way? I had to do something on our PS3 title for particles as well as they were taking upwards of 8+ms sometimes (!!!), so I went with a 1/16th sized buffer and a single post process 'cleanup' step (~0.5ms) on that buffer before blending it back. It looks mostly ok but the artifacts I see on what I did look suspiciously similar to what I see on R2's particles as well...

30% for a 60 Hz game might be a good upper bound. I think there was an Insomniac presentation which quoted a high number like this. Cannot remember if it was for early R2 (possibly a 60Hz target then?), might not make given (I think) the shipped R2 is a 30Hz game.

Ah ok, fair enough. I was defaulting to 30hz in my mind. For 60hz I guess 20% or even 30% may be possible, although I'm probably drop the hammer down closer to 20-25% if I could.

As long as CPU/GPU memory access isn't a problem (ie your GPU can write out to CPU memory, or has unified memory, or the CPU can quickly access GPU memory), and the CPU has a serious vector unit (which the SPUs qualify for) with enough bandwidth, then doing post processing CPU side can make sense if you have free CPU time. Sure wouldn't try this on the 360 however. If you go way back to the old SGIs (O2, etc) which had unified memory, you might be doing some post processing CPU side. Likely in the future as GPUs get more CPUified, everything will stay GPU. However if PS4 ends up with both a DX11 class GPU and a lot of new SPUs, you might very well want post SPU side just to find enough to keep them busy.

You know I'm still not 100% sold on splitting post processing between the cpu and gpu. I guess there are cases where it can be done and/or makes sense, but it seems like the bang for the buck you get from the cpu in that regard isn't ideal on this generation. PS3 does have monster vector units, but you would munch up so many of them to do what the gpu would handle easier, not to mention dma bandwidth use, etc... Plus keeping post processing all gpu makes sharing and reuse of post process steps so much easier. Quick example of that, I was bored between projects so I implemented the 'sun shafts' shown in the ShaderX6 book. I think it was 4 or 5 post process steps for that. Easy enough and it looked nice. Then I went back and optimize it. Since all our post process is done in gpu it was easy to reuse some of the data that the sun shafts needed from other steps, and better yet I was able to piggy back some of it on other steps. In the end, the entire sun shafts post process effect ended up only costing me ~0.45ms or so once I reused/reduced/recycled it into the exiting gpu post process pipeline. I was very pleased with that

It still may very well make sense for Killzone 2, but games are always adding more post processing in subsequent versions. So I can't help but wonder if at some point if someone went to the trouble of cpu-i-fying post process that they may run out of cpu and have to start shifting them slowly back to gpu anyways. Maybe I'd be more sold on a 16+ spu PS4, but not sure about this gen.

 

[GuestLV]

to joker454
Finally question is simple : in your honorable opinion can xbox360 achieve the same visual level as PS3 in KZ2?

 

[Laa-Yosh]

IMHO we have yet to see any game squeeze out as much of the X360's potential performance as KZ2 does with the PS3.

Gears is nice, really, but doing nowhere near as much. Perhaps whatever id's doing for a 30fps tech5 based game is going to push the hardware (so not Rage but maybe Doom4). Alan Wake doesn't look that complex either, nor any other exclusive, really.

 

[TimothyFarrar]

Hmm...you sure R2 is doing it that way? I had to do something on our PS3 title for particles as well as they were taking upwards of 8+ms sometimes (!!!), so I went with a 1/16th sized buffer and a single post process 'cleanup' step (~0.5ms) on that buffer before blending it back. It looks mostly ok but the artifacts I see on what I did look suspiciously similar to what I see on R2's particles as well...

Yes, at least in R2 multiplayer the 2x2 pixelization artifacts from the 4xMSAA trick are surely there, as well as low resolution artifacts (and blend back artifacts) from a second particle pass at what might very well be 1/16th sized buffer (but this time not using the 4xMSAA trick during drawing).

I might have to revise my prediction about KZ2's particles.

The 4xMSAA low resolution particle artifacts are clear on this set of August images (appears to be direct framebuffer grabs), http://kotaku.com/5041397/new-killzone-2-screenshots. Look at the first muzzle flash image at 720P. Then check out the rocket image (2x2 pixel blocks). Also seems as if the small high detail particles are directly blending (perhaps into the G-Buffer) at full resolution. R2 does something similar with high detail particles at full resolution.

However, I don't see any post August KZ2 shots with the 4xMSAA artifacts. Could either be doctored for public consumption shots, or that they indeed changed the particle rendering. I see evidence in at least one shot that they might now be drawing to a downsampled buffer and later merging back. View this shot at 720P http://ps3.ign.com/dor/objects/748475/killzone-next-gen/images/killzone-2-20081209055122390.html. Look where the explosion is behind the sandbags, looks more like the Battlefield Bad Company particle upsizing. Perhaps the change was to provide downsize particle rendering which adapts to overdraw by changing resolution.

Also the one who suggested film grain that I was seeing in low resolution particles was right (and it appears applied to the entire screen as a post process), http://ps3.ign.com/dor/objects/748475/killzone-2/images/killzone-2-20081209055139343.html. Looks like film grain is nicely used to hide quantization in the 8-bit tonemapping/2xLDR.

 

[vanquish]

IMHO we have yet to see any game squeeze out as much of the X360's potential performance as KZ2 does with the PS3.

Gears is nice, really, but doing nowhere near as much. Perhaps whatever id's doing for a 30fps tech5 based game is going to push the hardware (so not Rage but maybe Doom4). Alan Wake doesn't look that complex either, nor any other exclusive, really.

I think the problem is that there's no comparable development going on for the 360.
Most exclusives are third party titles that usually don't push the hardware, and there is nothing like Killzone 2. IE A first party title 4 years in the making, with an unlimited budget, running on an engine desgined ground up for the PS3.

Gears 2 took two years two complete (with UT3 released in between) and runs on a MP engine, originally designed for PCs.

And I don't think the 360 can match KZ2 in visuals, because KZ2 visuals depend heavily on deferred rendering which it troublesome on 360. So the 360 might have good looking games, but they will likely be impressive in different ways compared to Killzone 2.

The only really impressive 360 exclusive developer so far has been Rare, and they do multiple simultaneous projects and use a non realistic art style.

 

[Laa-Yosh]

And I don't think the 360 can match KZ2 in visuals, because KZ2 visuals depend heavily on deferred rendering which it troublesome on 360. So the 360 might have good looking games, but they will likely be impressive in different ways compared to Killzone 2.

The only real advantage from deferred rendering in KZ2 is that they can use a few hundred light sources per scene instead of a few dozen at max.

(I dunno how many GTA4 has at any time during the night, but it should be around that; then again, lighting in GTA4 is deferred too, but it does run on the 360.)

What KZ2 visuals depend on actually are tight art direction, high quality and very efficient artwork (texture budget per character seems to be way lower then Gears but most people won't really notice it) and very good post processing. I hope the GDC slides will have some before/after stuff to support my point here. It really adds a lot... You guys just wouldn't believe how crappy our CG stuff looks like straight out of the renderer and how much we add in post, either.

So it actually does come down to the budget. If a talented 360 developer gets a similar amount of time then they could produce something similarly cool.
It's just that MS doesn't really need that right now so they probably won't throw money at it.

 

[joker454]

View this shot at 720P http://ps3.ign.com/dor/objects/748475/killzone-next-gen/images/killzone-2-20081209055122390.html. Look where the explosion is behind the sandbags, looks more like the Battlefield Bad Company particle upsizing.

Good pic, yeah that's a classic upscaled look. I wouldn't be surprised if KZ2 went with 1/16th particle buffers as well given how little detail some of those particles have anyways, and it frees up some ram as well compared to 1/4 size buffers. It makes soft particles cheaper as well, and the overall fillrate hit way more predictable.

Finally question is simple : in your honorable opinion can xbox360 achieve the same visual level as PS3 in KZ2?

Definitely not going there, no more epic threads for me

 

[Nesh]

The only really impressive 360 exclusive developer so far has been Rare, and they do multiple simultaneous projects and use a non realistic art style.

I cant seem to remember an impressive looking title made from Rare to the 360.

No I didnt like Banjo's visuals.

 

[Nano]

I believe it is possible for Xbox 360 to realise a similar visual fidelity one day.

I agree with the point that there really isn't a similar exclusive production for the console in terms of budget, time, and goals. Whereas PS3 not only has KZ2, but other huge developments in the works like WarDevil.

If not by a 1st party developer, a 3rd party like id Software (Doom 4) or Crytek may have a few technical showcases for the platform whether they look better or worse.

I cant seem to remember an impressive looking title made from Rare to the 360.

No I didnt like Banjo's visuals.

Personally I think Viva Pinata, Kameo and PDZ each have some rather cool technical merits, especially considering they weren't the biggest budget productions on 360. IMO they were very pretty titles at the time

 

[Dr. Nick]

Definitely not going there, no more epic threads for me

Aww, you're no fun.

 

[Laa-Yosh]

While I expect a lot from id - and not so much from Crytek, given how they're not used to limited resources - they're going to make a multiplatform game which is already keeping them from pushing the system closer to its limits.

 

[Nano]

Very true.

 

[betan]

The known story behind the memory usage is that the default base OS level has been reduced, but there are overheads for including features, multiple megabytes to add Friends List support for example. This list of memory requirement made for painful reading, and adding basic functionality gobbled up RAM. Nothing has been heard on the matter since that first discussion though. I hope to Betsy Sony have made savings there, because the listed figures really were insane!

Yep they were insane at the time. Don't know the situation now, but cost of many of those features probably aren't really big of a deal considering HDD swap and the fact that most of those interfaces aren't even needed during gameplay. The friendlist for an MP game for example, will only be necessary when you are in the menu before setting up a game or party.

More significantly though is that most of us will treat the hdd as optional and assume it's not there. This isn't due to any favoritism or conspiracy theories, but just business realities. Basically for many of us to stay alive, we desperately need to be able to work on the $199 console. Without that, the layoffs and company purges you are seeing happen would have been far more widespread. So as cool as the standard hdd may be, it will be used mostly in an optional manner.

I sure hope GG or any other PS3 exclusive developer don't treat hdd as optional.

It still may very well make sense for Killzone 2, but games are always adding more post processing in subsequent versions. So I can't help but wonder if at some point if someone went to the trouble of cpu-i-fying post process that they may run out of cpu and have to start shifting them slowly back to gpu anyways. Maybe I'd be more sold on a 16+ spu PS4, but not sure about this gen.

Post processing on SPU is undeniably more troublesome than GPU, but if they ran out of head space for the sequel for some reason, they can always do additional post processing on the GPU.
Maybe even more importantly though, the post processing is not the only thing that's improved in the sequels, one would think. And if anything, people seem to be much better at "running out of gpu" than cpu.

 

[homerdog]

I sure hope GG or any other PS3 exclusive developer don't treat hdd as optional.

Confused me at first too, but I think he was referring to the 360. Unless there is some HDDless PS3 SKU planned that I'm not aware of.