How do I wait for vertical retrace?

[Samuel Thibault]

Barry Scott, le Thu 08 May 2008 10:36:37 +0100, a écrit :
> Glynn Clements wrote:
> > Carsten Haitzler (The Rasterman) wrote:
> >
> >   
> >> wonderful... in theory. in practice a lot of hardware ONLY provides a vblank
> >> interrupt. no interrupt for line X. :(
> >>     
> >
> > You don't need the signal to come directly from the video hardware. If
> > you know your clock frequencies, you can use the OS' timers; you just
> > need to phase-lock to vsync to prevent drift.
> >
> >   
> Without the signal from the hardware you cannot avoid tearing. We tried 
> using
> OS timer to get smooth animation and it does not work very well on 
> Linux.

Maybe that's because your linux had a fixed-frequency RTC set to 100Hz ?
(thus not precise enough).

Samuel