Xbox 360/AA/AF

Should AA/AF be default on in the Xbox 360?


  • Total voters
    233
Lazy8s said:
Good image quality has moved out of the reach of conventional renderers.
Your thread on tile-based rendering was very nice but statements such as the one above only serve to label you as being narrow-minded. Are you seriously suggesting that an IMR system with full FP precision throughout the pipeline (vertex to frame buffer) cannot achieve "good" image quality?
 
Natoma said:
V3 said:
Yes but not at the expense of high frame rate. I can live with abit of jag here and there. But low frame rate, is motion sickness inducing for me.

But my point precisely is, games on tv's today either display at 30fps or 60fps. An x850xt pe with 4xAA/16xAF will run the most taxing games today, whether they be Doom 3, Half Life 2, Far Cry, or whatever, at 1024x768, around 70-120fps depending on the game. In the case of a tri-core cpu at 3.2Ghz and a graphics processor that's at least twice the speed, I'd think that AA/AF should be a given at 720p.

Most certainly at 480i/p.

Well if they can run the game at 120 fps, I would rather them do some motion blur by blending a couple of frames and output it at 60fps, before even going to AA/AF.
 
Neeyik:
Are you seriously suggesting that an IMR system with full FP precision throughout the pipeline (vertex to frame buffer) cannot achieve "good" image quality?
The relativity of "good" will be based on context where a TBDLR will finally be competing and framebuffer memory will be limited.
 
fresh said:
DemoCoder said:
Well, if you keep the frontbuffer in main ram, you can do it, or alternatively, get rid of stencil or alpha . Don't forget FB/HyperZ MSAA compression too.

It doesn't bode well for HDR + AA tho, or HDR usage at all. 720p HDR = 10.54mb. 720p HDR + AA = not possible.

Can't get rid of stencil or alpha. 32 bit render target is the minimum. Not so sure about compression. HyperZ is in addition to a 32bit z/stencil-buffer.

HyperZ data doesn't have to reside in the eDRAM buffer. Moreover, HyperZ is a catch-all marketing term that includes lossless MSAA FB compression. As for not allocating stencil or alpha, I don't know about the XBox 360, but on other 3D architectures it was possible.

Hidef + AA + HDR is possible even without enough edram ram.

Yes, and it will be dog slow, if you have to spill the backbuffer to main memory, or implement manual tiling. You go from 256Gb/s to 22gb/s. If the future is that all games are Hidef + AA + HDR, than the Xbox360 certainly isn't an architecture optimized for those requirements as your eDRAM is not living up to its potential, and you may as well have used that die space for something else.

If MS truly intended most games to use Hidef + AA +HDR, that would have required enough eDRAM to fit a 720p HDR 2xAA scene.
 
DemoCoder said:
fresh said:
DemoCoder said:
Well, if you keep the frontbuffer in main ram, you can do it, or alternatively, get rid of stencil or alpha . Don't forget FB/HyperZ MSAA compression too.

It doesn't bode well for HDR + AA tho, or HDR usage at all. 720p HDR = 10.54mb. 720p HDR + AA = not possible.

Can't get rid of stencil or alpha. 32 bit render target is the minimum. Not so sure about compression. HyperZ is in addition to a 32bit z/stencil-buffer.

HyperZ data doesn't have to reside in the eDRAM buffer. Moreover, HyperZ is a catch-all marketing term that includes lossless MSAA FB compression. As for not allocating stencil or alpha, I don't know about the XBox 360, but on other 3D architectures it was possible.

Hidef + AA + HDR is possible even without enough edram ram.

Yes, and it will be dog slow, if you have to spill the backbuffer to main memory, or implement manual tiling. You go from 256Gb/s to 22gb/s. If the future is that all games are Hidef + AA + HDR, than the Xbox360 certainly isn't an architecture optimized for those requirements as your eDRAM is not living up to its potential, and you may as well have used that die space for something else.

If MS truly intended most games to use Hidef + AA +HDR, that would have required enough eDRAM to fit a 720p HDR 2xAA scene.

Well, I'm tellin' ya - 32bit min for rendering surfaces, HyperZ is on edram, there's no compression afaict, and developers will have to tile their scenes to make hidef rendering possible with AA.. and no you don't go from 256gb to 22gb. You split your scene vertically/horizontally.. render half, a third or whatever into edram, copy it out to main ram, and repeat for the other tiles. There's some built in hardware support that makes it easier, but still it's PITA.. I'm not making this up :)
 
Natoma said:
But my point precisely is, games on tv's today either display at 30fps or 60fps. An x850xt pe with 4xAA/16xAF will run the most taxing games today, whether they be Doom 3, Half Life 2, Far Cry, or whatever, at 1024x768, around 70-120fps depending on the game. In the case of a tri-core cpu at 3.2Ghz and a graphics processor that's at least twice the speed, I'd think that AA/AF should be a given at 720p.

Most certainly at 480i/p.

Well, that just means that the new platform should be able to run HL2, D3 or FC at that resolution with AA and AF at a good framerate.
I expect X360 games to have much more eye-candy than those games.
Like DOA3 or PDO still look better than most PC games.
It's a different approach, and i hope they keep focusing on the eye candy first, then AA and AF if they can squeeze the performance out of the box.
 
fresh said:
Well, I'm tellin' ya - 32bit min for rendering surfaces, HyperZ is on edram, there's no compression afaict, and developers will have to tile their scenes to make hidef rendering possible with AA.. and no you don't go from 256gb to 22gb. You split your scene vertically/horizontally.. render half, a third or whatever into edram, copy it out to main ram, and repeat for the other tiles. There's some built in hardware support that makes it easier, but still it's PITA.. I'm not making this up :)

No tile compression? You don't seem very sure of yourself. This feature has existed on every MSAA implementation since GF3 and R300. Moreover, to be able to split the scene, you need to access to post-transform vertices, so now you've got to run your vertex shaders with transform only, cache up all the post-transformed data, and then potentially run them again later if the vertex shaders were doing setup for pixel shaders.

It's going to hurt performance and is such a PITA that most games aren't going to do it. Translation: Xbox360 is not a platform where wie will see HDR used everywhere.
 
DemoCoder said:
fresh said:
Well, I'm tellin' ya - 32bit min for rendering surfaces, HyperZ is on edram, there's no compression afaict, and developers will have to tile their scenes to make hidef rendering possible with AA.. and no you don't go from 256gb to 22gb. You split your scene vertically/horizontally.. render half, a third or whatever into edram, copy it out to main ram, and repeat for the other tiles. There's some built in hardware support that makes it easier, but still it's PITA.. I'm not making this up :)

No tile compression? You don't seem very sure of yourself. This feature has existed on every MSAA implementation since GF3 and R300. Moreover, to be able to split the scene, you need to access to post-transform vertices, so now you've got to run your vertex shaders with transform only, cache up all the post-transformed data, and then potentially run them again later if the vertex shaders were doing setup for pixel shaders.

It's going to hurt performance and is such a PITA that most games aren't going to do it. Translation: Xbox360 is not a platform where wie will see HDR used everywhere.

The only thing I'm not sure of is the MSAA compression. Haven't looked into it. The rest is correct.

You don't need access to the post-transform vertex cache if you reissue the entire scene. The game has to redraw, but there's a some hardware support to help out. I'm 100% on this, I'm sure someone else can confirm.
 
Compression doesn't save space but just bandwith so once you have edram you can design buses around a sweet spot (2x AA?) and forget about compression.
 
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