-- File:	IntPoly_PlaneSection.cdl
-- Created:	Mon Jul 17 10:30:44 1995
-- Author:	Stagiaire Alain JOURDAIN
--		<ajo@phobox>
---Copyright:	 Matra Datavision 1995


class PlaneSection from IntPoly

  ---Purpose: determines the section of a triangulated shape by a plane.
  --          The section is a set of edges. 


uses  Real                      from Standard,
      Integer                   from Standard,
      Boolean                   from Standard,
      Shape                     from TopoDS,
      Edge                      from TopoDS,
      Trsf                      from gp,
      Pln                       from gp,
      Pnt                       from gp,
      Pnt2d                     from gp,
      SequenceOfPnt2d           from TColgp,
      SequenceOfSequenceOfPnt2d from IntPoly,
      IndexedMapOfPnt2d         from IntPoly,
      Pnt2dHasher               from IntPoly
      
is    Create
      returns PlaneSection from IntPoly;
	
      Create (S : Shape from TopoDS;
      	      P : Pln   from gp)
      returns PlaneSection from IntPoly;
	
      Section (me : in out)
      is static;

      Intersect (me : in out; Point1    :     Pnt   from gp;
                              Point2    :     Pnt   from gp;
                              Point3    :     Pnt   from gp;
                              OutPoint1 : out Pnt2d from gp;
                              OutPoint2 : out Pnt2d from gp)
      ---Purpose: determines the 2 2D-points resulting of the intersection
      --          of the triangle (Point1,Point2,Point3) by the plane
      returns Boolean from Standard;	 

      Insert (me : in out; OldPnt : Pnt2d from gp;
                           ComPnt : Pnt2d from gp;
                           NewPnt : Pnt2d 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 :     Pnt2d from gp;
                           EndPnt :     Pnt2d from gp;
                           OutPnt : out Pnt2d 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 SequenceOfPnt2d 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 : Pnt2d from gp)
      ---Purpose: builds a section from Point in this way  
      --                       ___   ___   ___   ___
      --               Point--/__/--/__/--/__/--/__/--->
      is static;

      PrevConstruction (me : in out; Point : Pnt2d 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 Pnt2d
      --          this is a part of the section
      returns Edge from TopoDS;
      

fields
      myShape         : Shape                     from TopoDS;
      myTransform     : Trsf                      from gp;
      myBackTransform : Trsf                      from gp;
      mySection       : SequenceOfSequenceOfPnt2d from IntPoly;
      myMapBegPoints  : IndexedMapOfPnt2d         from IntPoly;
      myMapEndPoints  : IndexedMapOfPnt2d         from IntPoly;
      myCpt           : Integer                   from Standard;
      myIndex         : Integer                   from Standard;
      myNbEdges       : Integer                   from Standard;
      
end PlaneSection;