Re: [osg-users] Modifying scene graph in event handler is safe, right?
Thanks for the clarification, Robert! My viewers are running in SingleThreaded mode, so I should be OK, but it is definitely something to keep in mind. Cheers, Morne On Wed, Jan 21, 2009 at 1:01 PM, Robert Osfield wrote: > Hi Morne, > > You can modify the scene graph in the event traversal, just like you > can with the update traversal. The only thing you need to be careful > about is that if you are modifying StateSet (and its contents) and > Drawables and their a rendering threads that are using these still > running - this only happens for the DrawThreadPerContext and > CullThreadPerCameraDrawThreadPerContext threading models. The way to > avoid the main thread doing the updates and the rendering thread(s) > for overlapping is to make the StateSet and Drawable with a > DataVariance of DYNAMIC. > > Robert. > > On Wed, Jan 21, 2009 at 12:41 PM, Morné Pistorius > wrote: >> Hi all, >> >> I used to work under the rule of thumb to only ever modify my scene >> using update callbacks, but scanning the lists I found reference >> saying that modification anywhere outside the viewer.RenderTraversal() >> is safe. I just want to verify this: directly modifying my scene >> graph in an eventhandler should be safe, right? And this should still >> be safe if my scene is shared between multiple views (as in a >> composite viewer), but not if my scene is shared between more than one >> viewer window (assuming my viewers are created with a QGLWidget, >> instead of a QWidget in which case it will be safe again). I call >> viewer.frame() on a QTimer evnet as in the OSG QtViewer examples. >> >> Have I got that right? >> >> Thanks! >> >> Morne >> ___ >> osg-users mailing list >> osg-users@lists.openscenegraph.org >> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >> > ___ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Modifying scene graph in event handler is safe, right?
Hi Morne, You can modify the scene graph in the event traversal, just like you can with the update traversal. The only thing you need to be careful about is that if you are modifying StateSet (and its contents) and Drawables and their a rendering threads that are using these still running - this only happens for the DrawThreadPerContext and CullThreadPerCameraDrawThreadPerContext threading models. The way to avoid the main thread doing the updates and the rendering thread(s) for overlapping is to make the StateSet and Drawable with a DataVariance of DYNAMIC. Robert. On Wed, Jan 21, 2009 at 12:41 PM, Morné Pistorius wrote: > Hi all, > > I used to work under the rule of thumb to only ever modify my scene > using update callbacks, but scanning the lists I found reference > saying that modification anywhere outside the viewer.RenderTraversal() > is safe. I just want to verify this: directly modifying my scene > graph in an eventhandler should be safe, right? And this should still > be safe if my scene is shared between multiple views (as in a > composite viewer), but not if my scene is shared between more than one > viewer window (assuming my viewers are created with a QGLWidget, > instead of a QWidget in which case it will be safe again). I call > viewer.frame() on a QTimer evnet as in the OSG QtViewer examples. > > Have I got that right? > > Thanks! > > Morne > ___ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
[osg-users] Modifying scene graph in event handler is safe, right?
Hi all, I used to work under the rule of thumb to only ever modify my scene using update callbacks, but scanning the lists I found reference saying that modification anywhere outside the viewer.RenderTraversal() is safe. I just want to verify this: directly modifying my scene graph in an eventhandler should be safe, right? And this should still be safe if my scene is shared between multiple views (as in a composite viewer), but not if my scene is shared between more than one viewer window (assuming my viewers are created with a QGLWidget, instead of a QWidget in which case it will be safe again). I call viewer.frame() on a QTimer evnet as in the OSG QtViewer examples. Have I got that right? Thanks! Morne ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
