What is the connection between onscreen and offscreen windows?

1
A couple of times I have experienced problems with graphics in
relation to DrawText and even when copying between two offscreen
windows. Both times I have been able to cancel the error with
simply sending a dummy texture to the onscreen window, like this:

Screen('DrawTexture', w, dummy_texture); (...note I do not even flip
the buffer afterwards)

Do anyone have a good explanation of why this is? Perhaps my
understanding of onscreen windows and offscreen windows is lacking a
bit. Are not the onscreen and offscreen windows independent locations?

Thanks,
Anders
2
Have a look at a couple of our FAQ's:

<http://psychtoolbox.org/wikka.php?wakka=PsychtoolboxFaq>

and be more specific in what you did and what you expected and
what really happened. Also, make sure you use the latest 'beta'.

-mario

--- In psychtoolbox@yahoogroups.com, "petersen.anders" <petersen.anders@...> wrote:
>
> A couple of times I have experienced problems with graphics in
> relation to DrawText and even when copying between two offscreen
> windows. Both times I have been able to cancel the error with
> simply sending a dummy texture to the onscreen window, like this:
>
> Screen('DrawTexture', w, dummy_texture); (...note I do not even flip
> the buffer afterwards)
>
> Do anyone have a good explanation of why this is? Perhaps my
> understanding of onscreen windows and offscreen windows is lacking a
> bit. Are not the onscreen and offscreen windows independent locations?
>
> Thanks,
> Anders
>
3
Hello forum

Thank you Mario for responding so quickly. Finally I found out that
I even had problems running basic demos like DriftDemo and
DriftDemo2. There was a vertical bar located in the moving pattern
that was not updated...). With this in mind I immediately got
suspicious with regards to my graphics card driver. My graphics card
is an ATI Mobility Radeon 9000. So after updating the driver all
graphical problems disappeared and my code was suddenly running
smoothly!

Hope others can avoid the same problem with this posting,

Anders

--- In psychtoolbox@yahoogroups.com, "Mario Kleiner"
<mario.kleiner@...> wrote:
>
> Have a look at a couple of our FAQ's:
>
> <http://psychtoolbox.org/wikka.php?wakka=PsychtoolboxFaq>
>
> and be more specific in what you did and what you expected and
> what really happened. Also, make sure you use the latest 'beta'.
>
> -mario
>
> --- In psychtoolbox@yahoogroups.com, "petersen.anders"
<petersen.anders@> wrote:
> >
> > A couple of times I have experienced problems with graphics in
> > relation to DrawText and even when copying between two offscreen
> > windows. Both times I have been able to cancel the error
with
> > simply sending a dummy texture to the onscreen window, like
this:
> >
> > Screen('DrawTexture', w, dummy_texture); (...note I do not even
flip
> > the buffer afterwards)
> >
> > Do anyone have a good explanation of why this is? Perhaps my
> > understanding of onscreen windows and offscreen windows is
lacking a
> > bit. Are not the onscreen and offscreen windows independent
locations?
> >
> > Thanks,
> > Anders
> >
>