From: Geert Uytterhoeven <Geert.Uytterhoeven@cs.kuleuven.ac.be>
  To  : ggi-develop@eskimo.com
  Date: Fri, 31 Jul 1998 15:56:24 +0200 (CEST)

Re: I've seen the stars too... [Re: kgicon, etc]

On Thu, 30 Jul 1998, Andrew Apted wrote:
> Geert writes:
> >  > Splitline is no good.  I've tried it, but what happens is that when you
> >  > _move_ the splitline (e.g. up 8 lines), you often miss the VGA's line
> >  > counter.  It is an exact comparison, so no ywrap occurs for that frame,
> >  > resulting in a flash of garbage on the screen.  Real ugly.
> >  
> >  You could do it during the vblank. On Amiga, the copper lists are changed
> >  during the vblank only to prevent this kind of annoying effects.
> 
> Yes, assuming that today's PC video cards have a vblank interrupt.
> (I doubt busy waiting on the vblank register would be a good idea).
> 
> Anyone here know what PC cards can and _can't_ give an interrupt for
> vertical retrace ?

ATI Mach64 has.

Greetings,

						Geert

--
Geert Uytterhoeven                     Geert.Uytterhoeven@cs.kuleuven.ac.be
Wavelets, Linux/{m68k~Amiga,PPC~CHRP}  http://www.cs.kuleuven.ac.be/~geert/
Department of Computer Science -- Katholieke Universiteit Leuven -- Belgium