My building's aren't (yet) textured, so that removes the need for a texture atlas. However they are individually shaped (being created from an ESRI shape file essentially), so instancing is ruled out.
I might try to group the buildings into tiles of equal size, trying to run the osgUtil::Optimizer with MERGE_GEOMETRY and MERGE_DRAWABLES individually on each tile. Let's see how that goes. If it is too slow, I will have to refactor my code that generates buildings. Also I am wondering what the SPATIALIZE_GROUPS feature of the optimizer does. Christian 2015-09-07 12:32 GMT+02:00 Robert Osfield <[email protected]>: > 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 < > [email protected]> 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 >> [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 > >
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