Re: Second Sight SVGA Board Info (text onl

[nathan@cco.caltech.edu (Nathan Mates)]

In article <375dlj$960@paris.ics.uci.edu>, Orion Pax <jlee@ics.uci.edu> wrote:
>Hm..I just thought of something.  Why the 15 fps shadowing speed on
>320x200x256?  I think this was only if you were using non-AppleColor
>RGB monitor or something and the card had to translate 32k of screen
>to 128k.  But, what if about the true VGA 320x200x256 mode where
>we write directly to the 128k.  Then there should be no shadowing
>going on and no shadowing at 15 fps problems, unless I missing something
>(no doubt).

   The main problem is that VGA is 128K, and it'll be on a board, not
main memory. Thus, writing stuff directly to the card would require
special coding, and it's kinda hard to rewrite Modulae at the moment.
It's the card's emulation of SHR that's the 15fps limitation: you have
to translate SHR video access into VGA, and make sure it's up for at
least one refresh (1/30 of a second).

   If some people can get a decent QDII implementation for it,
especially if things like lines/text/rectangles are offloaded to the
card's processor, stuff that does things legally could see a bit
speedup. One thing that would really help would be Shaston 8 built
into the card, then we could really see a speedup for Finder and
other general things.

Nathan Mates



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