-- File:	GeomFill_ConstantBiNormal.cdl
-- Created:	Tue Dec  9 18:33:12 1997
-- Author:	Philippe MANGIN
--		<pmn@sgi29>
---Copyright:	 Matra Datavision 1997


class   ConstantBiNormal from  GeomFill   
inherits TrihedronLaw  from  GeomFill 

	---Purpose: Defined an Trihedron Law  where the BiNormal, is fixed       

uses
 HCurve from  Adaptor3d, 
 Shape  from  GeomAbs, 
 Array1OfReal   from TColStd, 
 Vec    from  gp, 
 Dir  from  gp,
 Frenet from GeomFill
 
raises
 OutOfRange,  ConstructionError
is  

   Create(BiNormal : Dir from gp)
   returns  ConstantBiNormal from  GeomFill;   

   Copy(me)   
   returns  TrihedronLaw  from  GeomFill          
   is  redefined;
 
   SetCurve(me : mutable;  C  :  HCurve  from  Adaptor3d) 
   is  redefined;

-- 
-- 
--========== To compute Location and derivatives Location
--              
   D0(me : mutable; 
      Param: Real; 
      Tangent    : out  Vec  from  gp; 
      Normal     : out  Vec  from  gp; 
      BiNormal   : out  Vec  from  gp)
      ---Purpose: Computes Triedrhon on curve at parameter <Param>         
   returns Boolean  is  redefined;
	
   D1(me : mutable;
      Param: Real;       
      Tangent    : out  Vec  from  gp;  
      DTangent   : out  Vec  from  gp; 
      Normal     : out  Vec  from  gp; 
      DNormal    : out  Vec  from  gp;                 
      BiNormal   : out  Vec  from  gp; 
      DBiNormal  : out  Vec  from  gp)
      ---Purpose: Computes Triedrhon and  derivative Trihedron  on curve
      --          at parameter <Param>                
      --  Warning : It used only for C1 or C2 aproximation
   returns Boolean  
   is  redefined; 
   
   D2(me : mutable;
      Param: Real;       
      Tangent    : out  Vec  from  gp;  
      DTangent   : out  Vec  from  gp; 
      D2Tangent  : out  Vec  from  gp; 
      Normal     : out  Vec  from  gp; 
      DNormal    : out  Vec  from  gp;                 
      D2Normal   : out  Vec  from  gp; 
      BiNormal   : out  Vec  from  gp; 
      DBiNormal  : out  Vec  from  gp; 
      D2BiNormal : out  Vec  from  gp)    
      ---Purpose: compute  Trihedron on curve          
      --          first and seconde  derivatives.
      --  Warning : It used only for C2 aproximation
   returns Boolean
   is  redefined; 
--
--  =================== Management  of  continuity  ===================
--                 
   NbIntervals(me; S : Shape from GeomAbs) 
	---Purpose: Returns  the number  of  intervals for  continuity
	--          <S>. 
        --          May be one if Continuity(me) >= <S>
   returns Integer  is  redefined;

   Intervals(me; T : in out Array1OfReal from TColStd; 
    	         S : Shape from GeomAbs)
	---Purpose: Stores in <T> the  parameters bounding the intervals
	--          of continuity <S>.
	--          
	--          The array must provide  enough room to  accomodate
	--          for the parameters. i.e. T.Length() > NbIntervals()
    raises
    	OutOfRange from Standard 
    is redefined;  
     
	  
--  ===================  To help   computation of  Tolerance   ===============	 
    GetAverageLaw(me  :  mutable;
      ATangent    : out  Vec  from  gp; 
      ANormal     : out  Vec  from  gp; 
      ABiNormal   : out  Vec  from  gp) 
     ---Purpose: Gets average value of Tangent(t) and Normal(t) it is usfull to 
     --          make fast approximation of rational  surfaces.        
  is  redefined;

--   =================== To help Particular case   ===============	
   
    IsConstant(me) 
    ---Purpose:  Says if the law is Constant.  
    returns  Boolean   
    is redefined;  

    IsOnlyBy3dCurve(me) 
     ---Purpose: Return True.        
    returns  Boolean   
    is redefined;       

fields 
    BN :  Vec  from  gp;
    frenet : Frenet from GeomFill;
end ConstantBiNormal;