"Xen0s*" <Xen0s@ba.it> wrote in message 
news:aV6xe.98298$75.4460656@news4.tin.it...
>
> "Brenden D. Chase" <brenden.chaseREMOVE@THISgmail.com> ha scritto nel 
> messaggio news:i1%we.38049$R21.5046@lakeread06...
>
>
>>>> HAHA...  its been told that the AA will have to be programmed into a 
>>>> core in the cell.  Unlike Microsoft who paid more for an actual chip 
>>>> that does it.
>>>
>>> Cell can be post processing or vertex shading, AA is another thing, 
>>> you're a bit confused
>>
>> so unconfuse me if you think i am.
>>
>> explain your answer
>
> I'll try, but It's hard 'cause I don't write well in english, so I hope to 
> be clear..
>
> well, the spe in cell was originally thought very similar to "gpu 
> pipeline", but sony found the performance very disappointing, so sony put 
> a more hardware capable into ps3, the rsx
>
> as all people knows, despite the fact that rsx will do majority of 3d 
> operation, Cell and rsx could interact in some ways
> the most accredited is that Cell can perform Vertex Process, 'cause rsx is 
> able to fetch it with vertex data
> another option is "post processing", so *after* that rsx finish to work on 
> the frame buffer, rsx send the framebuffer to Cell's spe for further 
> processing
>
> (this is theory, I don't know if the bandwidth is adequate to perform this 
> data exchange)
>
> full screen anti aliasing fall in the middle of rendering,  deeply rooted 
> in what rsx do, take an example for supersampling FSAA (this is the only 
> AA feasible with HDR rendering turned on)
>
> the scene is rendered at very high resolution (up to 4 times the 
> original), then downsampled and scaled to output resolution, this can be 
> done only by the hardware that do the rendering, in the original location 
> of the frame buffer, and can't definitively done in a postprocessing time
>
> however super sampling is very very bandwidth eater and the data easy fill 
> the bus slowing down dramaticly the general performace by a 40-55% (the 
> only direct-to-mem bus of rsx is a 700 Mhz 128 bit that is like a 350Mhz 
> of a 256 bit pc video card) if you think that p3 will use 1080p resolution
>
> 1080p is very heavy, it count a total of 2 milion of pixel, supersampling 
> with this amount of pixel is a performance suicide
> (an option can be turn off HDR and use the multisampling of rsx, with a 
> performance hit of 30-40%, but the lack of HDR graphically is far beyond 
> worse than a lack of AA)
>
> for this reason can be arduous to see ps3 games with aa, at least in his 
> firsts years of life, maybe later the devs will found some tricks to 
> overcome the problem, who knows..
>
> Xenos works very differently, AA is computed internally by a second core 
> of the gpu that include both logic transistor
>
> this core perform "on the fly" operations on the framebuffer (that is in 
> the eDRAM) as like AA, stenciling, hdr and so on, without to touch and 
> take up the GPU--MEM bus or the GPU--CPU bus, with a, well known, internal 
> bus of 256 GB/s
>
> that's why framebuffer operations on x360 will came "for free" and this is 
> the reason why microsoft pretend AA on every single title for his console
>
> in reality this don't came magicly "for free" many believe because the 
> second core make xenos a little more expensive, then a rsx solution
> however to debate purpose, the performance hit of this solution is 1-5%
>
> I hope that my crappy english is sufficient clear and I hope that is 
> possibile a debate without insults
>
>

Thanks for explaining. But i knew about the vertex shading too. However, 
that hit to the performance is going to be huge at higher resolutions. That 
is why i dont think we will ever see a game running in 1080p. Besides how 
many people out there have a TV that does it??


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