The Game Technology discussion thread *Read first post before posting*

[Billy Idol]

Yeah, nice overview, although a bit old by now

The Catmull-Clark scheme is the industry standard for movie VFX and animation, although different renderers implement different kinds of UV smoothing, which can cause some confusion.

DX11 tesselation is a completely different approach, because it's not using discrete levels of subdivision, it adds new vertices continuously.

Do you have some actual references (links?) about how the DX11 tesselation scheme/algorithm works?

 

[sebbbi]

Incidentally some 360 games do this also when transparency is extreme. I worked on one game where the transparencies were 1/4 sized on the 360 version (I 1/16th them on the PS3 version) which sounds extreme but there was so little detail in these transparencies that no one was gonna notice even when we did many screen fulls of overdraw. I think sebbbi's awesome 360 game Trials HD does it as well, I believe I see artifacts on the explosions. More often than not though, alpha can be considered free on 360 for 'typical' gaming alpha needs.

Yes, we render all the particles in half resolution (using 4xMSAA to "downsample" the depth and color and do the blending). This trick was used, because our GPU processed particle engine can transform/animate/sort/render tens of thousands particles per frame, and all our particles receive lighting (particles are normal mapped and shadow mapped). The amount of overdraw can be huge, and our particle pixel cost is pretty steep. A nice side effect of this technique is that you get pseudo-volumetric look to the particles, as the particle clipping to surfaces is considerably smoothed by the 4xMSAA. There are some slight rendering errors on sharp edges when there is very bright explosion on background, but 4x speed was worth the small sacrifice.

 

[Acert93]

sebbbi, graphically, your game is pretty amazing. I like the compromises you guys made. There are some nitpicks (the bloom and aliasing on the rider needs to be addressed imo; less issues being explosion fire and the pixelated check points). But that is being pretty picky--you guys made a lot of good choices and the end result is really cohesive and looks very nice. Particles look great. Both Trials and LP1 both pretty much validate that a smart quarter buffer with MSAA can make for killer particles that most will never notice the resolution difference. So 4x faster or 4x the detail=win!

I cannot wait to see what you guys do with outdoor/mud/dirt&dust tracks

 

[corduroygt]

Best particle effects I've seen are in KZ2 and they make do with quarter resolution just fine, so I don't know if rendering particles at full res will make a significant improvement in IQ and that bandwidth is better used for something else.

 

[AlNom]

Smoke is a rather low frequency matter so there isn't much detail in the first place. Once you get into higher frequency details (such as fire or lightning or debris or decals etc), there is a line to draw before the upscale becomes noticeable. That will be up to artist discretion and knowledge of the circumstances surrounding the use of those effects - how far away is the effect from the camera, how short a time is the effect...

will make a significant improvement in IQ and that bandwidth is better used for something else.

The idea is that you'd have to be able to display a multitude of effects simultaneously with a very real bandwidth limit, but lowering the res beyond a certain point would create a noticeable disparity with other graphics on-screen or it might be harshly judged in a multiplatform title.

 

[2real4tv]

SSAO is a computational issue, not a memory one. If they wanted to hide lower resolution textures, they would use a detail texture blended with the existing textures...

Is it better texture filtering?

 

[2real4tv]

Smoke is a rather low frequency matter so there isn't much detail in the first place. Once you get into higher frequency details (such as fire or lightning or debris or decals etc), there is a line to draw before the upscale becomes noticeable. That will be up to artist discretion and knowledge of the circumstances surrounding the use of those effects - how far away is the effect from the camera, how short a time is the effect... Smoke doesn't tend to linger very long in KZ2...


The idea is that you'd have to be able to display a multitude of effects simultaneously with a very real bandwidth limit, but lowering the res beyond a certain point would create a noticeable disparity with other graphics on-screen or it might be harshly judged in a multiplatform title.

You sure about that iirc it lingers longer than most games.

 

[brain_stew]

Yeah, I think that 360 would support SSAO regardless of texture quality. It’s not in the PS3 because the current version of Unreal Engine for it does not support SSAO.

Is that correct or do developers not just disable it for performance reasons? Is there any reason why Epic's SSAO implementation wouldn't run on RSX?

 

[2real4tv]

Is that correct or do developers not just disable it for performance reasons? Is there any reason why Epic's SSAO implementation wouldn't run on RSX?

Its fairly new on 360, the first game to have it was GeOW2. The first ps3 to have it was U2(I think).

 

[brain_stew]

Is it better texture filtering?

It looks to me like the PS3 does indeed benefit from better texture filtering but that's not all that's going on here. The base textures are certainly higher resolution in some parts, see the picture with dude's face for example. It could just be a simple texture streaming bug though, UE3 has been notorious for causing errors like this and the mandatory install may have alleviated these problems from the PS3 build.

 

[AlNom]

Ack, it's late. I was thinking of the lighting from grenade explosions being a short time.

 

[Alucardx23]

Is that correct or do developers not just disable it for performance reasons? Is there any reason why Epic's SSAO implementation wouldn't run on RSX?

Don’t really know the reason why SSAO is not supported on PS3, but since Gears 2 there has been a lot of Unreal Engine 3.5 games that support the effect on 360 but not on PS3. What is sure is that the PS3 can do the effect as shown by Uncharted 2.

 

[N_B]

Its fairly new on 360, the first game to have it was GeOW2. The first ps3 to have it was U2(I think).

Apparently LittleBigPlanet used it:

http://forum.beyond3d.com/showpost.php?p=1344198&postcount=565

Which I guess makes sense in a game like that.

 

[2real4tv]

Ack, it's late. I was thinking of the lighting from grenade explosions being a short time.

Yeah definitely one of the weak points. The flamethower as an example.

 

[brain_stew]

Smoke is a rather low frequency matter so there isn't much detail in the first place. Once you get into higher frequency details (such as fire or lightning or debris or decals etc), there is a line to draw before the upscale becomes noticeable. That will be up to artist discretion and knowledge of the circumstances surrounding the use of those effects - how far away is the effect from the camera, how short a time is the effect... Smoke doesn't tend to linger very long in KZ2...


The idea is that you'd have to be able to display a multitude of effects simultaneously with a very real bandwidth limit, but lowering the res beyond a certain point would create a noticeable disparity with other graphics on-screen or it might be harshly judged in a multiplatform title.

Well after seeing the amount of people comment on Lost Planet delivering "the best explosions ever" despite using a 1/4 size buffer I don't think many mind the tradeoff. You've just got to be clever with the usage and make sure a lot of low resolution transparencies don't linger around for a long time and people won't notice.

Heck, I've been playing the PC version of RE5 at 1080p lately and even with a keen eye for this stuff and in a situation where it should stand out the most, it doesn't seem to stand out. I think the fact that LP2, KZ2 and UC2 all use a low resolution buffer and yet are considered the best looking games of this generation by many is evidence enough that its a decent trade off.

 

[Alucardx23]

Must have been a bad port by lazy devs Kidding aside, it's not due to disk space, the game installed to hdd is only 3.3gb.

I remember that something like this happened with oblivion and Fallout 3. What might be and explanation for the texture quality difference in and open world game between the 360 and PS3. Because isn’t the 360 capable of using more texture memory than the PS3?

Fallout 3
http://www.eurogamer.net/articles/x360-v-ps3-multiformat-face-off-round-three-article?page=2

Oblivion
http://www.eurogamer.net/articles/fallout-3-triple-format-face-off-article?page=3

 

[AlNom]

Yeah, 1/4 res isn't too bad for certain things... using MSAA helped in Lost Planet but the explosion effect is a combination of other post-processes including motion blur, which would hide that as well. Of course, explosions aren't the only transparencies though...

I was referring to when the buffer is even lower than that - joker mentioned a 1/16 res for instance...

 

[AlNom]

Is that correct or do developers not just disable it for performance reasons? Is there any reason why Epic's SSAO implementation wouldn't run on RSX?

SSAO is a computational issue

Their SSAO involves texture lookups/sampling/filtering so there could be some implications on RSX/G7x (stalling) as one of the ALUs per fragment shader pipe handles the texture address processing. For instance, Epic mentioned doing a fog computation in parallel on Xbox 360 as the ALUs and texture processors are completely orthogonal.

 

[MazingerDUDE]

Smoke doesn't tend to linger very long in KZ2...

It definitely does to the extent that it'll affect the game play.

http://www.youtube.com/watch?v=9zovcY0PpRw

In fact, I don't recall there being any game with longer lasting smoke than KZ2.

 

[Rangers]

Well after seeing the amount of people comment on Lost Planet delivering "the best explosions ever" despite using a 1/4 size buffer I don't think many mind the tradeoff. You've just got to be clever with the usage and make sure a lot of low resolution transparencies don't linger around for a long time and people won't notice.

Heck, I've been playing the PC version of RE5 at 1080p lately and even with a keen eye for this stuff and in a situation where it should stand out the most, it doesn't seem to stand out. I think the fact that LP2, KZ2 and UC2 all use a low resolution buffer and yet are considered the best looking games of this generation by many is evidence enough that its a decent trade off.

Funny, I thought the original Uncharted 1 and LP explosions both were amazing at the times.

That was before I learned from B3D to recognize the low res buffers. But I guess that's the point, they stood out to me as explosions better than others I'd seen. Obviously the tradeoff worked correctly.

Of course they'd look even better in hi res though. That is one thing I notice in Crysis which has all that brute force to play with, the high res explosions.