fVDI, Was Re: SCSI problems

From: Johan Klockars <rand_at_cd.chalmers.se>
Date: Thu, 11 Dec 1997 12:06:56 +0100 (MET)

> Since it's clean I wil never get any ISA ATI Mach64 card for my NOVA

Don't give up yet. Magnus managed to find one, eventually.

> interface, I am going to write drivers for a more common ISA VGA card, let's
> say Trident SVGA, or whatever else. I hope I get the card to generate some
> screen output, maybe even to copy the current Videl videoram to it. But I am

For 'standard' cards there are X sources that can be investigated.

> quite sure I am unable to write a VDI driver. So if you are going to port
> fVDI to TOS/MiNT, it might help me a lot.

Actually, fVDI currently _only_ runs under TOS/MiNT. It's supposed to be
a Fenix shared library later on, but right now there's no Fenix, so...

At the moment I'm working on the split between the VDI 'engine' and the
hardware drivers, but the last version before this was actually almost usable.

fVDI currently relies a little on having a working VDI behind it, but a
test I made some time ago showed that letting it handle all normal VDI
screen output still gave a usable desktop and some programs I tried also
worked relatively well!
That version only had the small VDI font (which it always placed slightly
off the correct position vertically), it had no support for vro_cpyfm
(scrolling etc), all the more complex VDI operations (arc drawing etc) were
missing, and it did most operations on a pixel by pixel basis. Still, as I
said, it could be used (with a bit of good will).

Porting fVDI to new hardware is about as simple as it gets. You only need
to supply functions for:
- set pixel
- get pixel
- hardware initialization/control (not used yet)
- set palette (not used yet)
fVDI will then transform all higher level calls to these.

Naturally, you can replace the default functions with your own optimized
versions later. The only extension the current fVDI has beyond the above
is accelerated line drawing (which of course speeds up solid fills as well).
A bitplane optimized vrt_cpyfm is in the works (drawing text pixel by pixel
is not such a good idea ;-) and I will add an optimized vro_cpyfm ASAP (if
someone has good multi-bitplane blitting code, I'm very interested).

If anyone is interested in helping out with this project, please get in
touch with me. Perhaps you have some old code in a drawer somewhere?

  Chalmers University   | Why are these |  e-mail:   rand_at_cd.chalmers.se
     of Technology      |  .signatures  |            johan_at_rand.thn.htu.se
                        | so hard to do |  WWW/ftp:  rand.thn.htu.se
   Gothenburg, Sweden   |     well?     |            (MGIFv5, QLem, BAD MOOD)
Received on to. des. 11 1997 - 12:22:00 CET

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