Hi Christian, Since you are creating the building yourself I would recommend that you build them grouped to start off with rather than post process them.
The first step I'd tack would be to create a texture atlas from the wall and roof textures and then just create a single osg::Geometry and associated osg::StateSet. This will half the number of Drawables and state changes. If you have a set of roof and wall textures then see if you create a single texture atlas from them so that you can then reuse the same osg::StateSet between separate Drawables. Then final step would be to merge groups of Drawables that are in geographical location. The osgforest example does grouping of randomly placed trees so have a look at ways of doing this. Another approach you could take would be to create a single osg::Geometry and then use instances to repeat the building geometry and provide a size for a shader to scale the geometry and place it in it's final position. Again the osgforest has a code path that does this so have a look at this. Robert. On 7 September 2015 at 10:50, Christian Buchner <christian.buch...@gmail.com > wrote: > Hi, > > we're using code loading some buildings (outline and height), creating a > Geode with a two drawables per individual building - one drawable for the > walls, one for the roof polygon. This has served us well to display a few > hundred to a few thousand buildings. > > Fast forward to current date. Our client has sent us a new geo data set > containing 55000 building polygons. Once you zoom out the camera to show > most of these buildings, frame rates drop into the low single digit, mostly > due to all the culling effort done by the CPU (maybe also from the large > number of draw calls). D'oh! > > Are there any specific features within OSG to group close by geodes, and > to merge their drawables? > > I know the osgUtil::Optimize has flags for merging geodes and drawables, > but I guess it would not automatically merge only very close objects. > > What path should I try to take for tackling this problem, if possible > using built-in OSG features? > > Christian > > > > _______________________________________________ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > >
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