[osg-users] Slave cameras in a view

Karl Heijdenberg karl.heijdenberg.osg at gmail.com
Wed Oct 17 01:18:52 PDT 2007


Hi and thanks for the tip about where to look for code for the
projectionOffset. I now have a slave camera with the expected projection
offset next to the master camera.

One thing that I found out was that the slave camera is drawn one frame
after the master. Both cameras are drawn to the same graphics context. I can
easily see this in the seam between the two cameras by moving my scene up or
down at a constant speed. My slave camera is then drawn a at a constant
distance behind my master camera.

In the osgwindow example separate graphics contexts are used for master and
slave cameras. Is that the way it should be done? And then why?

If I set up the two cameras with different graphics contexts they draw
within the same frame (when I use the "thread per context" threading model).

Regards Karl


On 10/15/07, Robert Osfield <robert.osfield at gmail.com> wrote:
>
> Hi Karl,
>
> Have a look at the osgwindows example, or the
> View::setUpViewAcrossScreens() source code in
> src/osgViewer/Viewer.cpp.
>
> On 10/10/07, Karl Heijdenberg <karl.heijdenberg.osg at gmail.com> wrote:
> > Hi,
> >
> > I'm trying to add two cameras to one View in compositeViewer.
> > The first camera is added as a master camera and the second as a slave
> > camera.
> >
> > Frustums for the cameras:
> > master={-50, 0, -40, 40}
> >  slave={0, 50, -40, 40}
> >
> > For the first camera I set the projectionMatrix with
> > setProjectionMatrixAsFrustum.
> >
> > How do I calculate the projectionOffset for the slave camera?
> >
> > The offset is needed in call to addSlave(osg::Camera* camera,const
> > osg::Matrix& projectionOffset, const osg::Matrix& viewOffset, bool
> > useMastersSceneData=true);
> >
> > I've also tried to set the reference frame to
> ABSOLUTE_RF_INHERIT_VIEWPOINT
> > and then call the setProjectionMatrixAsFrustum for both cameras. This
> test
> > ended up in a black scene for the second camera. Am I missing something?
> >
> > Thanks, Karl
> > _______________________________________________
> > osg-users mailing list
> > osg-users at lists.openscenegraph.org
> >
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> >
> >
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