(S)VGA Tricks - Part 4
This text comes from IMPHOBIA Issue XII - July 1996
* Hardware BitBLT *
Well, I can't develop the way to do Hardware BitBLT in this article, but
i'll try to do it in Part II. Just some words:
In fact, Hardware BitBLT is really (and only?) usefull to clear a screen or
to copy a background in SVGA modes (at least if you don't want to rebuild your
code for each BitBLT processor). You can really improve your code if you use a
really high definition like 640x480 or 800x600... For my part, i used it in
320x200x32K to scroll a background (128k to restore), and I really got 5 more
frames/sec on a 486 DX40, using BitBLT.
BitBLTs are stable in SVGAs modes... Don't use it in VGA modes !!! Don't use
it in the 320x200x256 multipages provided by UniVBE 5.1, and don't use it in
24 bits modes ( 3 BYTES / colors ) (BitBLT gets a bit confused when it has to
work with 3 bytes/col, in particular on S3).
Greets to all my friends, all TFL-TDV members, all kewl guyz of the scene I
got a nice chat with, and all guyz who will greet me and my group in the
future ;-)
I especially thanx Bismarck/TFL-TDV and Access/Antares for accepting SVGA at
Wired 95, Wizard/Imphobia and Walken/Impact Studios for some inspirations.
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The demo "Hurtless" we presented at Wired 95, featured 320x200/640x200
Hi-Color, 320x200x256 chained multipages, BitBLT, FLAT LINEAR, Video RAM
booster support, WITH or WITHOUT UniVBE, and N-Buffering. Have a look if you
want to see the thing working (however the demo might be unstable because of
the intensive use of Mikmod 2.03 virtual timers... but maybe we'll do a
special release with a new version of Mikmod. The SB support is really random)
It is available on ftp.cdrom.com, ftp.arosnet.se and hagar.arts.kuleuven.ac.be
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Contact me at the following addresses:
Laurent Lardinois
271 chauss‚e de Saint Job
1180 Bruxelles, Belgium
(C) 1996 Type One / TFL-TDV
P.S.: You know the funniest ? I don't have an S3 !