On Tuesday 01 February 2005 16:13, Timothy Miller wrote:
> That's the thing... we've discussed coverage, full-screen
> antialiasing, subpixel coordinates and the like, and the experts here
> have almost unanimously said that they're unnecessary.  (Some can be
> emulated anyhow.)
>
> If we decide to support it now or in the future, it'll matter, but
> for now, it seems to be something we can just drop.
>
> If you have a compelling argument contrary to that, feel free to
> discuss it with the others.  Note that the design, as it is, has
> probably seriously blown our transistor budget, so don't get your
> hopes up, even about some things that are ALREADY in there.

Yes, it's reality.  I have been making some effort to understand exactly 
what this FPGA is capable of, and how that maps to the 3D pipeline.  
Did you say the part would be the XC3S2000?

A key point here is that the design will fall back to iterating when it 
runs out of dedicated components, which means that instead of blowing 
the transistor budget, it just slows down.  Hopefully, not to a crawl.

Another point is, the first rev doesn't have to implement everything, it 
only absolutely needs to implement enough to run xscreensaver-gl and we 
will win.

> BTW, font-rendering from xft is pre-antialiased. It's just a grayscale
> bitmap that we use as the alpha channel while texturing.

Right, and subpixel positioning can be expressed through U and V.  I'll 
go back and sort through the archives and see if I can find the 
arguments.  My intuition is still that it's a better and more regular 
design to send X and Y in the same format.  It's hardly enough of an 
overhead to worry about.  This is probably a good time to segue into 
exactly what the DMA command stream is going to look like.  I know you 
talked about it a little, and worried that the bandwidth could be 
excessive without some clever tricks.

Regards,

Daniel
_______________________________________________
Open-graphics mailing list
[email protected]
http://lists.duskglow.com/mailman/listinfo/open-graphics
List service provided by Duskglow Consulting, LLC (www.duskglow.com)

Reply via email to