Date   : Tue, 30 Jan 1996 13:40:09 GMT
From   : lamcw <lamcw@...>
Subject: Re: Vertical blank interrupt

David Alan Gilbert <gilbertd@...> wrote:

;Hmm - I go the whole hog and simulate the scanout process; every 64us
(or whatever
;is programmed into the CRTC) of simulated time I read a scanline of
data from the
;beebs memory and display it. At the same time I read palette registers
and the like.


Yes, this IS the way to do it. I realised after I coded the damn thing
and I can't be bothered to redo it. Besides Beeb software isn't too
demanding in this respect, not compared to Atari 8bit stuff anyway.

However, don't display to the screen at every scanline. Build up the image
in memory and then spit it out to the screen during the VBI for instance.

Chris Lam,
MacBeebEm Keeper.