Hi Renzo, Maybe a node visitor with z-near and z-far as parameter is a possible approach. Werner
On 15. Oktober 2020 09:46:57 MESZ, OpenSceneGraph Users <osg-users@lists.openscenegraph.org> wrote: > >Hi Robert, > >On 14-Oct-20 3:56 PM, OpenSceneGraph Users wrote: > >Hi Renzo, > > >On Wed, 14 Oct 2020 at 12:00, OpenSceneGraph Users ><osg-users@lists.openscenegraph.org> wrote: > >I am using osg::Drawable::getBoundingBox() to retrieve the bounding box >around the whole geometry. Is there a similar short way to get the >equivalent box for just the culled geometry or do I need to write my >own procedure? > > >Culling isn't related to the nodes directly, but to a traversersal of >the scene graph that compares the bounding shere's of internal nodes of >the scene graph and the bounding boxes of the drawable leaves. Culling >can happen at any point in the hierarchy - it can cull right up at the >top node in the scene graph if the scene is outside the view frustum. > > >Within the cull traversal there is no tracking of culled or non culling >bounding boxes, a cull test is done and the bool result used directly. >There isn't a "bounding box" or "bounding sphere" for culled or non >culled objects. All the cull traversal cares about is building a list >of drawables leaves that pass the view frustum test, there is no >tracking of any objects that are culled - this would be a crazy waste >of CPU resources. > > >I have to ask, why do you want a bounding box of culled objects - what >is the high level problem you are trying to solve? It may well be that >you are asking the wrong question thinking about the task you have in >the wrong way. > > >Robert. > > >thanks for pointing out how cull traversal operates. > >Yes, it might be I am searching in the wrong direction. I need to get >the minimum and the maximum Z coordinate of the geometry vertices in >order to apply a color range. This is quite easy to do for the whole >geometry but I would know if there is a way just for the vertices >inside the view frustum. > >Regards, >Renzo > > > >------------------------------------------------------------------------ > >_______________________________________________ >osg-users mailing list >osg-users@lists.openscenegraph.org >http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
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