2008/1/29, Lubos Lunak <l.lunak@suse.cz>:
> On Thursday 24 of January 2008, cedric wrote:
> > Hello, I'm desperatly trying to create a wobbly-like-compiz effet on kwin.
> > (I attach my current results)
> >
> > I have trouble tuning the parameters and I get an "oscillation" effect :/
>
>  It unfortunately does not work at all here, with SVN trunk. When I try to
> change geometry in any way, it results in the whole screen repainted in
> strange ways, it looks a bit like huge broken zoom, exploding from the
> window. Is that what you mean with oscillation?

It was a bug that I fix now, some constrains between the physical
parameters of the grid and the time.elapsed between 2 frames. (If you
relax the constrains on the model, it may diverge if too much time was
spent since the last update)

>
> > I implemented a little qt4 app to easyly test my algo and try to correctly
> > tune it.
>
>  This one works right for me though.
>
> > If someone have an idea to improve it, please let me know it.
>
>  I can't comment on the algorithm itself, as I have no idea how it works,

I understood how it work thank to some code that Anton Moiseev sent to
me, I could not manage to get large grid works correctly, and in fact,
we cannot easyly do that, what should be done is using a 4x4 grid and
create a bezier surface to interpolate the other texture points.
Given the fact that a 4x4 grid work well in my test app, I should have
a working wobbly effect quickly. I'll try to implement it in my test
app this saturday, and if it works, i'll transpose it to kwin.

> but
> other things I see:
>
> - the things done in prePaintScreen() should be done only when necessary -
> e.g. PAINT_SCREEN_WITH_TRANSFORMED_WINDOWS has a noticeable performance hit

ok, i'll try to understand better how compositing works with kwin,
anyway, I'll post my first "rough" version that works with kwin to get
feedback.

> - since your paintWindow() checks for !w->isSpecialWindow(), it would be
> better to do this before trying to add any window to 'windows'. This way
> unnecessary windows may be processed.

agreed.

>
> --
> Lubos Lunak
> KDE developer
> --------------------------------------------------------------
> SUSE LINUX, s.r.o.   e-mail: l.lunak@suse.cz , l.lunak@kde.org
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> Czech Republic       http//www.suse.cz
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