[maemo-developers] gtk clutter tearing

[From: Kimmo Hämäläinen]

On Tue, 2009-12-29 at 16:17 +0100, Tamminen Eero (Nokia-D/Helsinki)
wrote:
> Hi,
> 
> ext Mark Clarkson wrote:
> > I have made a simple animation using a clutter timeline with clutter-gtk-0.10 and clutter-1.0 but there is excessive tearing when the animation plays making the animation look terrible.
> > 
> > I have tried none, dri and glx values for the CLUTTER_VBLANK environment variable but this seems to have no effect at all.
> > 
> > Is there a way to fix this?
> 
> Screen update isn't yet synched to LCD refresh.  Please file a bug about
> it to bugs.maemo.org (it needs support from kernel display driver, X
> server, SGX driver, Clutter and hildon-desktop compositor, but I guess
> you could file it against Official platform -> Core -> X).

Don't hold your breath with this one. At the moment it seems a proper
vsync support is not going to be implemented in Maemo 5. There is a
possibility to use a vsync even now, but the implementation is not good
enough: if you enable the current vsync, the OpenGL application is
blocked on glSwapBuffers until vsync comes, which prevents the
application to prepare the next frame (and drops FPS too low).

I think doing like Bounce does is the best you can do: use fullscreen
window and disable the compositor (in hildon-desktop). Recent
hildon-desktop versions disable compositing automatically for fullscreen
windows, unless you use HildonStackableWindow (which requires the
sliding animation).

-Kimmo