0026147: Visualization - restore the ability to pick only fully included objects in rectangular selection

2 modes of rectangular selection are available: inclusion-only and overlap-allowing;
The modes can be switched using method AllowOverlapDetection from StdSelect_ViewerSelector3d;
BVH for sensitive entities now builds if there is more than max number of leafs in collection;
Added option -allowoverlap to command vselect;
Interactive rectangular selection in Draw is now available in 2 modes:
- if the user starts selection from upper corners, only fully included objects will be selected;
- if the user starts selection from lower corners, both partially and fully overlapped objects will be selected.

src/StdSelect/StdSelect_ViewerSelector3d.cxx

@@ -668,3 +668,15 @@ void StdSelect_ViewerSelector3d::ResetSelectionActivationStatus()
 {
   resetSelectionActivationStatus();
 }
+
+//=======================================================================
+//function : AllowOverlapDetection
+//purpose  : Sets the detection type: if theIsToAllow is false,
+//           only fully included sensitives will be detected, otherwise
+//           the algorithm will mark both included and overlapped entities
+//           as matched
+//=======================================================================
+void StdSelect_ViewerSelector3d::AllowOverlapDetection (const Standard_Boolean theIsToAllow)
+{
+  mySelectingVolumeMgr.AllowOverlapDetection (theIsToAllow);
+}

src/StdSelect/StdSelect_ViewerSelector3d.hxx

@@ -87,6 +87,11 @@ public:
 
   Standard_EXPORT virtual Standard_Boolean HasDepthClipping (const Handle(SelectMgr_EntityOwner)& theOwner) const Standard_OVERRIDE;
 
+  //! Is used for rectangular selection only
+  //! If theIsToAllow is false, only fully included sensitives will be detected, otherwise the algorithm will
+  //! mark both included and overlapped entities as matched
+  Standard_EXPORT void AllowOverlapDetection (const Standard_Boolean theIsToAllow);
+
   DEFINE_STANDARD_RTTI(StdSelect_ViewerSelector3d)
 
 protected: