AVS Forum banner
Status
Not open for further replies.
1 - 13 of 13 Posts

·
Registered
Joined
·
6,850 Posts
Discussion Starter · #1 ·
I have seen a few article on Transparency Anti-Aliasing such as this one from Beyond3D and I am curious to know whether the PS3 or X-box 360 are capable of it. Has anyone heard if either consoles GPU is capable of Super-Sample Transparency AA?
 

·
Registered
Joined
·
1,730 Posts
Alpha channel Multi-sample anti-aliasing (aka, Transparancy AA) is a feature of the nVidia G70 family of GPUs......the GeForce 7800 GTX is one part of that G70 family and the RSX GPU in the PS3 is another part of the G70 family...


In other words, yes, PS3 will support it..



As far as Xenos/C1 goes, although there has been no specific mention of Alpha channel Multi-sample anti-aliasing, I would imagine you would be able to do something similar with the MEMEXPORT function on Xenos/C1 by performing multiple texture writes in ram (one for visible vertex and another mapped to alpha channel pixels)...


In short, even if there is no direct X360 HW support for alpha channel AA, you should be able to deploy the effect in software, albiet with a negative cost to performance....
 

·
Registered
Joined
·
454 Posts
Where are you deriving your information klee? Sources please.
 

·
Registered
Joined
·
2,378 Posts
Hey wow, that super-sampling AA transparency really made a difference on that fence. Looking forward to seeing it in action!
 

·
Registered
Joined
·
6,850 Posts
Discussion Starter · #5 ·
Quote:
Originally Posted by KLee
In short, even if there is no direct X360 HW support for alpha channel AA, you should be able to deploy the effect in software, albiet with a negative cost to performance....
Just curious but is their anyway that Transparancy AA could be done in the 10 MB of eDRAM? Also if not how much of a drop in performance would it be if it was done in software?
 

·
Registered
Joined
·
183 Posts
Wow...big difference - I didn't even notice there were two guards in the corner on the other side of the fence in the first pics. Very nice...


And yes, everything I've heard points to both next gen machines utilizing this tool, or something similar....


I'm dying for the 360 to launch. November can't come soon enough!! :D
 

·
Banned
Joined
·
13,980 Posts
well there are "jaggies" though minor in many of the screenshots released for the xbox360 games already. I don't see it as a problem, the higher the res the less apparent the "jaggie", which is one reason why the 720 games on the xbox look so much better as they are less noticeable (all other factors being the same).
 

·
Registered
Joined
·
1,730 Posts
Quote:
Originally Posted by Richard Paul
Just curious but is their anyway that Transparancy AA could be done in the 10 MB of eDRAM? Also if not how much of a drop in performance would it be if it was done in software?
As you may or may not know, 10MB of eDRAM is not big enough to fit an entire 720p frame+4X FSAA+Z check+stencil in the frame buffer:


MB No FSAA 2X FSAA 4X FSAA


640x480 2.3MB 4.7MB 9.4MB

1280x720 7.0MB 14.0MB(too big) 28.1MB(too big)

1920x540 7.9MB 15.8MB(too big) 31.6MB(too big)



The Xenos/C1 gets around this problem via Tile Rendering...aka Deferred Rendering ...Sega Dreamcast fans are familar with this term since the Power VR architecture was a deferred renderer as well...


With the Power VR solution, the Dreamcast used lots of very small tiles for deffered rendering, but Xenos uses very large tiles to do DR work (a max of 4 tiles per frame):



(# of Tiles) No FSAA 2x FSAA 4x FSAA

640x480 1 1 1

1280x720 1 2 3

1920x540 1 2 4



Whats so brilliant about the Xenox/C1 solution is the fact MS found a way to use a Z only pass to assist with tiling the screen to optimise eDRAM utilisation....they use Hierarchical Z as a sort of accumilation buffer for pixel/vertex data....apperently they are doing it fast enough they can calculate Z, stencil and AA samples for every pixel/vertex displayed in less than 1/60th of a second....


Since Xenos can have access to alpha color pixel data from main ram via MEMEXPORT, they *should* be able to also include that data in the Hierarchical Z accumilation buffer and output Alpha channel Antialiasing to the screen ala nVidia G70 based solutions (GeForce 7800GTX, RSX), though the costs to CPU performance is unknown at this point (memexport locks 1/3rd L2 cache for GPU access to ram)


In short, you shoud be able to get those fancy transparancy AA effects on both PS3 and X360 :)

Quote:
Originally Posted by LiveCrazy Joe
Where are you deriving your information klee? Sources please.


http://www.beyond3d.com/articles/xenos/index.php?p=05

http://www.beyond3d.com/previews/nvi...index.php?p=06

http://www.extremetech.com/article2/...1830190,00.asp


The RSX is part of the G70 family so its a no brainer PS3 will be able to do this as well...
 

·
Registered
Joined
·
6,850 Posts
Discussion Starter · #12 ·
KLee, thanks for the explanation of how the Xbox 360 might do Transparency AA. Also have you heard of any developers either for the PS3 or Xbox 360 that are planning on using it in their games?
 

·
Registered
Joined
·
1,730 Posts
Not that I have heard of yet, No...


That is not to say it is not being used.....current PS3 Evaluation Kits have G70s in them and X360 betas have the full X360 feature set (albiet they run slower) so it is more than possible on either system games......



If I were to venture a guess, I would say it is more likely 1st Gen X360 titles are *not* using it, because X360 betas only arrived in July and X360 alpha kits are based on Apple G5 CPUs and ATI Radeon X800 or 9800XTs (first run of kits).....neither of those ATI cards can do alpha channel AA....


I would think 2nd gen games that are developed from scratch on final X360 SDKs are more likely to have AC AA...
 
1 - 13 of 13 Posts
Status
Not open for further replies.
Top