-- File:	IntPoly_ShapeSection.cdl
-- Created:	Tue Aug  1 09:14:30 1995
-- Author:	Stagiaire Alain JOURDAIN
--		<ajo@phobox>
---Copyright:	 Matra Datavision 1995


class ShapeSection from IntPoly

  ---Purpose: determines the section between 2 triangulated shapes.
  --          The section is a set of edges.

uses  Real                    from Standard,
      Integer                 from Standard,
      Boolean                 from Standard,
      Shape                   from TopoDS,
      Edge                    from TopoDS,
      Vec                     from gp,
      Pnt                     from gp,
      SequenceOfPnt           from TColgp,
      SequenceOfSequenceOfPnt from IntPoly,
      IndexedMapOfPnt         from IntPoly,
      PntHasher               from IntPoly

is    Create
      returns ShapeSection from IntPoly;
      
      Create (S1 : Shape from TopoDS;
              S2 : Shape from TopoDS)
      returns ShapeSection from IntPoly;
      
      Section (me : in out)
      is static;
      
      Explore (me : in out)
      is static;
      
      Intersect (me : in out; S1,S2,S3      :        Pnt  from gp;
                              OS1,VS0,V1,V2 :        Vec  from gp;
		              h1,h2,ah1,ah2 : in out Real from Standard)
      ---Purpose: determines if it exists, the intersection point between 
      --          the (S1,S2,S3) triangle and the edge pointed by V1 and V2.
      --          Returns True if the triangle-triangle section is found.
      returns Boolean from Standard;
      
      IsEqual (me : in out; Pt1,Pt2 : Pnt from gp)
      returns Boolean from Standard;			    

       IsInside (me : in out; P,P1,P2,P3 : Pnt from gp;
      	                      N0         : Vec from gp)
      ---Purpose: returns True if P is inside the (P1,P2,P3) triangle
      --          N0 = P1P2 ^ P1P3
      returns Boolean from Standard;			    

      InsertInMap (me : in out)
      ---Purpose: adds if necessary, myBegPoint in myMapBegPoint 
      --          and myEndPoint in  myMapEndPoint. 
      is static;

      Insert (me : in out; OldPnt : Pnt from gp;
                           ComPnt : Pnt from gp;
                           NewPnt : Pnt from gp)
      ---Purpose: sees whether OldPnt and NewPnt begins or ends a section
      --          created before and adds the 2 others points.
      --          If not, creates a section
      is static;
      
      Concat (me : in out; BegPnt :     Pnt from gp;
                           EndPnt :     Pnt from gp;
                           OutPnt : out Pnt from gp)
      ---Purpose: sees whether BegPnt or EndPnt begins or ends a section
      --          created before, and returns the other point to continue 
      --          the construction
      --          Returns 2 if the construction is 'Forward'
      --          Returns 1 if the construction is 'Previous'
      --          Returns 0 if not and creates a section
      returns Integer from Standard;
      
      ConcatSection (me : in out; Section   : in out SequenceOfPnt from TColgp; 
                                  NbSection :        Integer       from Standard;
				  Index     :        Integer       from Standard)
      ---Purpose: sees whether Section begins or ends another one in  mySection,
      --          from the rank 'Index' to the last one 'NbSection'
      is static;
      
      ForwConstruction (me : in out; Point : Pnt from gp)
      ---Purpose: builds a section from Point in this way  
      --                       ___   ___   ___   ___
      --               Point--/__/--/__/--/__/--/__/--->
      is static;

      PrevConstruction (me : in out; Point : Pnt from gp)
      ---Purpose: builds a section from Point in this way  
      --                    ___   ___   ___   ___
      --               <---/__/--/__/--/__/--/__/--Point
       is static;

      NbEdges (me : in out)
      returns Integer from Standard;
      
      Edge (me : in out; Index : Integer from Standard)
      ---Purpose: builds an edge from a sequence of Pnt
      --          this is a part of the whole section
      returns Edge from TopoDS;


fields
      myShape1       : Shape                   from TopoDS;
      myShape2       : Shape                   from TopoDS;
      mySection      : SequenceOfSequenceOfPnt from IntPoly;
      myMapBegPoints : IndexedMapOfPnt         from IntPoly;
      myMapEndPoints : IndexedMapOfPnt         from IntPoly;
      myBegPoint     : Pnt                     from gp;
      myEndPoint     : Pnt                     from gp;
      myFirstTime    : Boolean                 from Standard;
      myCpt          : Integer                 from Standard;
      myIndex        : Integer                 from Standard;
      myNbEdges      : Integer                 from Standard;

end ShapeSection;