Ignore agents without bounding boxes

components/detournavigator/navigatorimpl.cpp

@@ -18,6 +18,8 @@ namespace DetourNavigator
 
     void NavigatorImpl::addAgent(const osg::Vec3f& agentHalfExtents)
     {
+        if(agentHalfExtents.length2() <= 0)
+            return;
         ++mAgents[agentHalfExtents];
         mNavMeshManager.addAgent(agentHalfExtents);
     }