[osg-users] osgQt + OSG 3.6.2 Status

Mathieu MARACHE mathieu.marache at gmail.com
Fri Sep 14 08:15:11 PDT 2018

Hi Werner,

We share the same belief around Qt.

Concerning your implementation, it's not clear how you integrate the OpenGL
window into Qt. If you are willing to share a simple application that
demonstrates your setup that would be a nice start to understand and
discuss your approach ?

Recent versions of Qt5 use OpenGL to render many UI components and thus it
is not unfrequent to have many OpenGL context created inside an
application. It is my understanding that QOpenGLWidget and QOpenGLWindow
manage to make these OpenGL context handling transparent.
The main difference between these two is that the QOpenGLWidget is rendered
inside a ImageBuffer or something like that and that the QOpenGLWindow
mimics the Qt4's QGLWidget we were used to allowing QuadBuferring etc.. But
being a Window lots of the Widget inherited things have to be implemented
(mostly UI events).


On Tue, 11 Sep 2018 at 13:02, Werner Modenbach <Werner.Modenbach at texion.eu>

> Hi Mathieu,
> thanks for your support for OSG/Qt integration. I think there are really
> many people using OSG together with Qt.
> Qt is just great for building multi environment user interfaces.
> But there is one thing I don't really understand. There is some discussion
> sometimes about difficulties in this integration.
> My integration is dated April 2013 and I didn't need any changes since
> then.
> class Cl_3D_OsgViewer_QT : public QWidget, public osgViewer::Viewer {...
>  It works without any problems with every version of Qt since that time.
> So where is the problem?
> OK, I'm not using VS 20xx but Qt Creator and g++ instead. Maybe that makes
> the difference. But in this case
> it isn't really a problem of Qt integration but a VS problem.
> I see that some people tend integrating OSG into QOpenGLWindow.  In my
> opinion this is a stony way
> because Qt GL wasn't that stable and finally decided since many years now.
> So things change frequently
> and this is always causing headache for keeping integrations running.
> On the other hand I think there is nothing more developed and stable than
> QWidget.
> If someone needs help send me a PM and I'm willing to share my integration
> class.
> - Werner -
> Am 10.09.2018 um 18:42 schrieb Mathieu MARACHE:
> Back from holidays...
> Community support is thin when considering OpenSceneGraph with Qt. I am
> currenlty the only maintainer of osgQt because I have a software using it
> and I didn't want the project to be tossed out.
> The Qt4 way of doing things with legacy osgQt (that was droped from
> OpenSceneGraph) doesn't fit well with the Qt5 way of doing things. Since
> Qt5.7 there are even incompatibilities (black screens, etc.).
> Qt4 support is getting difficult, even debian is dropping Qt4 (
> https://wiki.debian.org/Qt4Removal).
> In anticipation I have proposed to drop Qt4 and concentrate only on Qt5.
> Robert only asked to keep the Qt4 version around and make it clear which
> version of osg compiles with which version/branch of osgQt.
> There is a feature branch (since Feb '18) of the Qt5 way of doing things
> awaiting testing and validation from the community. This is the code I use
> in my application which was crafted by paid support from KDab's Mike Krus
> (from which I had authorization to open source).
> https://github.com/openscenegraph/osgQt/tree/feature/osgQOpenGL
> Regards
> --
> nǝıɥʇɐƜ
> On Mon, 30 Jul 2018 at 17:07, Robert Osfield <robert.osfield at gmail.com>
> wrote:
>> On Mon, 30 Jul 2018 at 15:59, Andrew Cunningham <andrewC at mac.com> wrote:
>> >
>> > Back on the original topic :)
>> >
>> > This is a really simple QtOSGWidget that I used as a starting point for
>> an OSG widget in a QDialog. Simple and works fine.
>> >
>> > https://github.com/vicrucann/QtOSG-hello
>> Just had a quick look at the code.  It only works "fine" because there
>> it's a trivial example, it's buggy.  Please compare to the the
>> osg::Camera setup in the osgQt master and see if you can see the
>> error, in this example.  If you can then you'll be able to spot what
>> to fix in your own programs.
>> Robert.
>> _______________________________________________
>> osg-users mailing list
>> osg-users at lists.openscenegraph.org
>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
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