Robert, do you see this impacting the concept of data variance, which has traditionally had different semantics for a Drawable versus a Node?
Glenn Waldron / @glennwaldron On Tue, May 13, 2014 at 11:13 AM, Robert Osfield <[email protected]>wrote: > Hi All, > > Over the last day I have been experimenting with changing > osg::Drawable so that it is subclassed from osg::Node rather than > osg::Object. The motivation behind this change is to make it simpler > to build scene graphs that only contain a single geometry and enabling > one to just directly attach a Geometry to the scene graph, without the > need for decorating it with a Geode first. > > I have got the OSG build and running fine with this change, but I had > to make more changes to code that accessed Drawable than I'd have > liked, and this concerns me about the impact it may have on end users > that will be forced to update their code toI ideally I'd get things > to a point where very few users need to do anything more than a > recompile against the new version of the OSG. With this goal in mind > I'd like feedback from the community about what solutions > > The problem area is the overlap between the Node::getBound() that > returns a BoundingSphere and the Drawable::getBound() that returns a > BoundingBox. Any code that gets the bounding box from the Drawable > using the getBound() method will now fail to compile as it'll be > getting a BoundingSphere back in place. My current workaround to this > is to have a Drawable::getBoundingBox() method that the can be used to > directly access the Drawable's BoundingBox. This tweak is perfectly > valid implementation but it does require calling code to be modified. > > Might there be alternatives that C++ can help us with? In a perfect > world we'd be able to select the appropriate getBound() implementation > depending upon what type it's being assigned to ie.: > > // get the bounding sphere of the Drawable > const BoundingSphere& bs = drawable->getBound(); > > // but we also want the old code to keep compiling where we want > the bounding box > const BoundingBox& bb = drawable->getBound(); > > I'm currently trying to think of ways to solve this conundrum. There > might be a simple C++ trick that I've overlooked, which is why having > a nice big community of C++ programmers is an asset :-) > > So.... what's solutions can you think of? > > Robert. > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >
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