0029312: Using OBB to speed up Boolean Operations

1. Implementation of the user-defined option for usage of Oriented Bounding Boxes (OBB) in Boolean Operations for additional filtering (rejection) of selected for intersection pairs of sub-shapes.

By default the usage of OBB is turned off.
To enable/disable its usage the method SetUseOBB(flag) should be used. This method is available for all operations in Boolean Component.
To enable/disable it in draw the command "buseobb 0/1" should be used. Note, that this will affect all subsequent operations.

The OBB for the shapes are built by first necessity and stored into operation context (IntTools_Context).

2. Usage of the OBB in some test cases.

src/IntTools/IntTools_Context.cxx

@@ -14,6 +14,7 @@
 
 
 #include <Bnd_Box.hxx>
+#include <Bnd_OBB.hxx>
 #include <BRep_Tool.hxx>
 #include <BRepAdaptor_Surface.hxx>
 #include <BRepBndLib.hxx>
@@ -65,6 +66,7 @@ IntTools_Context::IntTools_Context()
   myProjSDataMap(100, myAllocator),
   myBndBoxDataMap(100, myAllocator),
   mySurfAdaptorMap(100, myAllocator),
+  myOBBMap(100, myAllocator),
   myCreateFlag(0),
   myPOnSTolerance(1.e-12)
 {
@@ -86,6 +88,7 @@ IntTools_Context::IntTools_Context
   myProjSDataMap(100, myAllocator),
   myBndBoxDataMap(100, myAllocator),
   mySurfAdaptorMap(100, myAllocator),
+  myOBBMap(100, myAllocator),
   myCreateFlag(1),
   myPOnSTolerance(1.e-12)
 {
@@ -183,6 +186,16 @@ IntTools_Context::~IntTools_Context()
     myAllocator->Free(anAdr);
   }
   mySurfAdaptorMap.Clear();
+  //
+  Bnd_OBB* pOBB;
+  aIt.Initialize(myOBBMap);
+  for (; aIt.More(); aIt.Next()) {
+    anAdr=aIt.Value();
+    pOBB=(Bnd_OBB*)anAdr;
+    (*pOBB).~Bnd_OBB();
+    myAllocator->Free(anAdr);
+  }
+  myOBBMap.Clear();
 }
 //=======================================================================
 //function : BndBox
@@ -472,6 +485,36 @@ Geom2dHatch_Hatcher& IntTools_Context::Hatcher(const TopoDS_Face& aF)
   return *pHatcher;
 }
 
+//=======================================================================
+//function : OBB
+//purpose  : 
+//=======================================================================
+Bnd_OBB& IntTools_Context::OBB(const TopoDS_Shape& aS,
+                               const Standard_Real theGap)
+{
+  Standard_Address anAdr;
+  Bnd_OBB* pBox;
+  //
+  if (!myOBBMap.IsBound(aS))
+  {
+    pBox = (Bnd_OBB*)myAllocator->Allocate(sizeof(Bnd_OBB));
+    new (pBox) Bnd_OBB();
+    //
+    Bnd_OBB &aBox = *pBox;
+    BRepBndLib::AddOBB(aS, aBox);
+    aBox.Enlarge(theGap);
+    //
+    anAdr = (Standard_Address)pBox;
+    myOBBMap.Bind(aS, anAdr);
+  }
+  else
+  {
+    anAdr = myOBBMap.Find(aS);
+    pBox = (Bnd_OBB*)anAdr;
+  }
+  return *pBox;
+}
+
 //=======================================================================
 //function : SurfaceData
 //purpose  : 

src/IntTools/IntTools_Context.hxx

@@ -45,6 +45,7 @@ class gp_Pnt2d;
 class IntTools_Curve;
 class Bnd_Box;
 class TopoDS_Shape;
+class Bnd_OBB;
 
 //! The intersection Context contains geometrical
 //! and topological toolkit (classifiers, projectors, etc).
@@ -98,6 +99,11 @@ Standard_EXPORT virtual  ~IntTools_Context();
   //! Returns a reference to surface adaptor for given face
   Standard_EXPORT BRepAdaptor_Surface& SurfaceAdaptor (const TopoDS_Face& theFace);
 
+  //! Builds and stores an Oriented Bounding Box for the shape.
+  //! Returns a reference to OBB.
+  Standard_EXPORT Bnd_OBB& OBB(const TopoDS_Shape& theShape,
+                               const Standard_Real theFuzzyValue = Precision::Confusion());
+
   //! Computes the boundaries of the face using surface adaptor
   Standard_EXPORT void UVBounds (const TopoDS_Face& theFace,
                                  Standard_Real& UMin,
@@ -256,6 +262,7 @@ protected:
   DataMapOfShapeAddress myProjSDataMap;
   DataMapOfShapeAddress myBndBoxDataMap;
   DataMapOfShapeAddress mySurfAdaptorMap;
+  DataMapOfShapeAddress myOBBMap; // Map of oriented bounding boxes
   Standard_Integer myCreateFlag;
   Standard_Real myPOnSTolerance;