Hi George, The DataVariance property of osg::Object is used in couple of ways. For internal nodes of the scene it is used as a hint to operations such as the osgUtil::Optimizer that parts of the scene graph are static or dynamic and to use this information as guide to what can be optimized and in what ways - generally it means leaving DYNAMIC nodes alone. The DataVariance property on Nodes isn't used during the update, cull and draw traversals so it's effectively ignored.
For the leaves of the scene graph - the osg::StateSet and osg::Drawable (and it's subclasses), the DataVariance is only used when using the DrawThreadPerContext and CullThreadPerCameraDrawThreadPerContext threading models and is used during the draw traversal to prevent the next frame from commensing till all DYNAMIC StateSet and Drawables are dispatch. For SingleThreaded and CullDrawThreadPerContext threading models the DataVariance is not used as the next frame doesn't commence till the whole draw dispatch is completed. The DataVariance of the StateAttribute subclasses is not used in update, cull or draw traversals, and like nodes is only used be specialist traversals like some of the ones contained in the Optimizer. So if you want to dynamic update a Uniform then the way to make sure that draw doesn't overlap the update of it is to set the DataVariance of the StateSet that enclose it to DYNAMIC. There isn't an automatic scheme to check the DataVariance of StateAttributes as it would be prohibitively expensive to do during the draw traversal. Robert. On 23 May 2012 16:36, George Bekos <[email protected]> wrote: > Hello OSGers! :) > > Let's say that I have an osg::StateSet with some osg::Materials or > osg::Uniforms attached to it. The osg::Material or osg::Uniform changes > values during the run time, and because of that I set their DataVariance to > DYNAMIC. Do I also have to set the DataVariance of the osg::StateSet to > DYNAMIC? What if I have an osg::Geode on which I add/remove Drawables during > the run-time? What if I have an osg::Drawable which I update its geometry in > every frame? Do I have to set the DataVariance of the osg::Geode to DYNAMIC? > Could someone tell me if (and when) the DataVariance property of an > osg::Object is inherited to its parent or children automatically? Thanks for > your time! > > Cheers, > George > > ------------------ > Read this topic online here: > http://forum.openscenegraph.org/viewtopic.php?p=47824#47824 > > > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
