[PD] Syncing an event with refresh rate in GEM

Roman Haefeli reduzierer at yahoo.de
Fri Oct 12 02:08:16 CEST 2007

On Thu, 2007-10-11 at 22:53 +0300, Batuhan Bozkurt wrote:
> Roman Haefeli wrote:
> > On Thu, 2007-10-11 at 18:55 +0200, IOhannes m zmoelnig wrote:
> >
> >   
> >> the next thing is to synchronize your trigger events with the gem-rendering.
> >>
> >>     
> >
> > while we are at: is there some way to hardsync Gem's framerate with the
> > screen refresh rate? 
> > i noticed, that when using [gemwin <screenrefreshrate>], both are quite
> > in synch, but not really. i made a patch, that shows a part of an image
> > with a very width. now, when scrolling the image from right to left with
> > a counter, that is hardsynced to [gemhead], i still see some glitches,
> > the scrolling is not stable in movement. 
> > wouldn't it be cool, to have an option for [gemwin], that automatically
> > hardsyncs it to screen refresh rate? [gemwin -1] ? is it possible at all
> > to get 'screen clock' (i don't know how this is called correctly) on
> > every os?
> >
> > roman
> >
> >   
> I think this is called vsync(and seen as an option on some systems as 
> ''sync to vblank'').
> And afaik this is not just tied to the software that is rendering things 
> to screen but to the graphics card driver itself. I'm very frustrated 
> about this in linux and windows.

thank you for all that info. though, it seems, that this is not the
answer, i was initially looking for, it addresses a few issues i had in
the past (mplayer -vo gl has tearing, gem has tearing) and which your
hint seems to be the solution to. 
i tried driconf (basically it's just a graphical tool, that simply
creates a file called .drirc). i enabled 'sync to vblank', and it
worked, though running your testpatch now eats the whole cpu. i tried
mplayer -vo gl (-vo gl is the opengl video output driver of mplayer) and
there it works without pegging the cpu. i tested also armagetron and it
worked as well.

have you an idea, why enabling 'sync to vblank' does make Gem pegging
the cpu? (ubuntu dapper, fresh gem-cvs, ati radeon mobility 9600, fglrx

i would also like to hear if other users can have it enabled while doing

for so many applications with gem, this option would make the result
looking soo much better. it would be a huge gain to have that working, i


Der frühe Vogel fängt den Wurm. Hier gelangen Sie zum neuen Yahoo! Mail: http://mail.yahoo.de

More information about the Pd-list mailing list