[osg-users] empty scene after resize

Michele Bosi michele.bosi at gmail.com
Tue Jul 15 01:36:04 PDT 2008


I just wanted to let you know how I solved my problem: it seems that
one has to avoid sending the resize events to OSG when the new size
has zero area, that is, the width or height are == 0. Basically I just
put the condition "if ( width * height )" in the Qt's resize event
handler before dispatching the resize event to OSG.

Cheers,
Michele

On Mon, Jul 14, 2008 at 11:08 PM, Robert Osfield
<robert.osfield at gmail.com> wrote:
> Hi Michele,
>
> This most likely will be because the viewport is going to 0,0,0,0 size
> and messing up projection matrix.  I'm afraid I don't have an straight
> forward solutions to this - it most likely will require so special
> catch code to handle this problem case.
>
> Robert.
>
> On Mon, Jul 14, 2008 at 10:05 PM, Michele Bosi <michele.bosi at gmail.com> wrote:
>> I am sure this is a known problem, but looking on the archives didn't
>> help, maybe I didn't come up with the right keywords, anyway... I am
>> using OSG 2.4 (but the problem was already there since OSG 2.0) under
>> both Win XP and Linux, with the Qt4 wrapper and when I resize the
>> window to zero width or height and then restore it the content of the
>> scene disappears (my program has 3d views that can be temprarily
>> hidden/restored). This behaviour seem not to be related to the driver
>> but to OSG since with OSG-based programs I get the same problem with
>> nVidias as well as with ATIs, while other non-OSG-based programs don't
>> show this problem.
>>
>> I suspect that with a zero-area viewport something breaks into the
>> culling mechanism or some division by zero mixes up some OSG internal
>> state or matrix.
>> Does anyone know how to fix or work around this? do I have to reset
>> something once I detect a non-zero area viewport in my resize event
>> handler?
>>
>> Thanks,
>> Michele
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>> osg-users at lists.openscenegraph.org
>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>>
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