// File:	ApproxInt_PrmPrmSvSurfaces.gxx
// Created:	Wed Mar 17 12:42:28 1993
// Author:	Laurent BUCHARD
//		<lbr@topsn3>

#define TOLTANGENCY 0.0000000001


#include <TColStd_Array1OfReal.hxx>
#include <math_FunctionSetRoot.hxx>

#define Debug(expr)  cout<<" expr :"<<expr;
#define MySurf1 MyIntersectionOn2S.Function().AuxillarSurface1()
#define MySurf2 MyIntersectionOn2S.Function().AuxillarSurface2()


//--------------------------------------------------------------------------------
ApproxInt_PrmPrmSvSurfaces::ApproxInt_PrmPrmSvSurfaces( const ThePSurface& Surf1
						       ,const ThePSurface& Surf2):
       MyHasBeenComputed(Standard_False),
       MyHasBeenComputedbis(Standard_False),
       MyIntersectionOn2S(Surf1,Surf2,TOLTANGENCY)
{ 
}
//--------------------------------------------------------------------------------
Standard_Boolean ApproxInt_PrmPrmSvSurfaces::Compute( Standard_Real& u1
						     ,Standard_Real& v1
						     ,Standard_Real& u2
						     ,Standard_Real& v2
						     ,gp_Pnt& P
						     ,gp_Vec& Tg
						     ,gp_Vec2d& Tguv1
						     ,gp_Vec2d& Tguv2) { 
  
  Standard_Real tu1=u1;
  Standard_Real tu2=u2;
  Standard_Real tv1=v1;
  Standard_Real tv2=v2;
  
  if(MyHasBeenComputed) { 
    if(  (MyParOnS1.X()==u1)&&(MyParOnS1.Y()==v1)
       &&(MyParOnS2.X()==u2)&&(MyParOnS2.Y()==v2)) {
      return(MyIsTangent);
    }
    else if(MyHasBeenComputedbis == Standard_False) { 
      MyTgbis         = MyTg;
      MyTguv1bis      = MyTguv1;
      MyTguv2bis      = MyTguv2;
      MyPntbis        = MyPnt;
      MyParOnS1bis    = MyParOnS1;
      MyParOnS2bis    = MyParOnS2;
      MyIsTangentbis  = MyIsTangent;
      MyHasBeenComputedbis = MyHasBeenComputed; 
    }
  }
  if(MyHasBeenComputedbis) { 
    if(  (MyParOnS1bis.X()==u1)&&(MyParOnS1bis.Y()==v1)
       &&(MyParOnS2bis.X()==u2)&&(MyParOnS2bis.Y()==v2)) {

      gp_Vec            TV(MyTg);
      gp_Vec2d          TV1(MyTguv1);
      gp_Vec2d          TV2(MyTguv2);
      gp_Pnt            TP(MyPnt);
      gp_Pnt2d          TP1(MyParOnS1);
      gp_Pnt2d          TP2(MyParOnS2);
      Standard_Boolean  TB=MyIsTangent;

      MyTg        = MyTgbis;
      MyTguv1     = MyTguv1bis;
      MyTguv2     = MyTguv2bis;
      MyPnt       = MyPntbis;
      MyParOnS1   = MyParOnS1bis;
      MyParOnS2   = MyParOnS2bis;
      MyIsTangent = MyIsTangentbis;

      MyTgbis         = TV;
      MyTguv1bis      = TV1;
      MyTguv2bis      = TV2;
      MyPntbis        = TP;
      MyParOnS1bis    = TP1;
      MyParOnS2bis    = TP2;
      MyIsTangentbis  = TB;

      return(MyIsTangent);
    }
  }


  MyIsTangent = Standard_True;

  static TColStd_Array1OfReal Param(1,4);
  Param(1) = u1; Param(2) = v1;
  Param(3) = u2; Param(4) = v2;
  math_FunctionSetRoot  Rsnld(MyIntersectionOn2S.Function());
  MyIntersectionOn2S.Perform(Param,Rsnld);
  if (!MyIntersectionOn2S.IsDone())  { 
    MyHasBeenComputed = MyHasBeenComputedbis = Standard_False;
    return(Standard_False);
  }
  if (MyIntersectionOn2S.IsEmpty()) {
    MyIsTangent=Standard_False;
    //cout<<"\n----- Parametree Parametree : IsEmpty ds Compute "<<endl;
    //Debug(u1); Debug(u2); Debug(v1); Debug(v2);   cout<<endl;
    MyHasBeenComputed = MyHasBeenComputedbis = Standard_False;
    return(Standard_False);
  }
  MyHasBeenComputed = Standard_True;
  MyPnt = P = MyIntersectionOn2S.Point().Value();
  
  MyIntersectionOn2S.Point().Parameters(u1,v1,u2,v2);
  MyParOnS1.SetCoord(tu1,tv1);
  MyParOnS2.SetCoord(tu2,tv2);
  
  if(MyIntersectionOn2S.IsTangent()) { 
    MyIsTangent=Standard_False;
    MyHasBeenComputed = MyHasBeenComputedbis = Standard_False;
    return(Standard_False); 
  }
  MyTg    = Tg    = MyIntersectionOn2S.Direction();
  MyTguv1 = Tguv1 = MyIntersectionOn2S.DirectionOnS1();
  MyTguv2 = Tguv2 = MyIntersectionOn2S.DirectionOnS2();

  //----------------------------------------------------------------------
  //-- Si ( Tg )    TU et TV sont normes 
  //-- 
  //-- On a    Tg   =  DeltaU  *  TU    +   DeltaV  *  TV
  //-- 
  //-- soit :  Tg.TU  =  DeltaU  TU.TU  +   DeltaV  TU.TV
  //--         Tg.TV  =  DeltaU  TV.TU  +   DeltaV  TV.TV 
  //-- 
  //-- Donc : 
  //--
  //--               Tg.TU TV.TV  - Tg.TV * TU.TV
  //--   DeltaU = -------------------------------
  //--               TU.TU TV.TV  - (TU.TV)**2
  //-- 
  //--               Tg.TV TU.TU  - Tg.TU * TU.TV
  //--   DeltaV = -------------------------------
  //--               TU.TU TV.TV  - (TU.TV)**2
  //--
  //--

  Tg.Normalize();    MyTg = Tg; 

  Standard_Real DeltaU,DeltaV;
  gp_Vec TU,TV;
  gp_Pnt Pbid;
  Standard_Real TUTV,TgTU,TgTV,TUTU,TVTV,DIS;
  //------------------------------------------------------------
  //-- Calcul de Tguv1
  //--
  ThePSurfaceTool::D1(MySurf1,u1,v1,Pbid,TU,TV);
  
  TUTU = TU.Dot(TU);
  TVTV = TV.Dot(TV);
  TUTV = TU.Dot(TV);
  TgTU = Tg.Dot(TU);
  TgTV = Tg.Dot(TV);
  DIS  = TUTU * TVTV - TUTV * TUTV;
  
  DeltaU = (TgTU * TVTV - TgTV * TUTV ) / DIS ; 
  DeltaV = (TgTV * TUTU - TgTU * TUTV ) / DIS ;

  Tguv1.SetCoord(DeltaU,DeltaV);  MyTguv1 = Tguv1;

  //------------------------------------------------------------
  //-- Calcul de Tguv2
  //--  
  ThePSurfaceTool::D1(MySurf2,u2,v2,Pbid,TU,TV);

  TUTU = TU.Dot(TU);
  TVTV = TV.Dot(TV);
  TUTV = TU.Dot(TV);
  TgTU = Tg.Dot(TU);
  TgTV = Tg.Dot(TV);
  DIS  = TUTU * TVTV - TUTV * TUTV;

  DeltaU = (TgTU * TVTV - TgTV * TUTV ) / DIS ; 
  DeltaV = (TgTV * TUTU - TgTU * TUTV ) / DIS ;
  
  Tguv2.SetCoord(DeltaU,DeltaV);  MyTguv2 = Tguv2;

  return(Standard_True);
}
//--------------------------------------------------------------------------------
void ApproxInt_PrmPrmSvSurfaces::Pnt(const Standard_Real u1,
				     const Standard_Real v1,
				     const Standard_Real u2,
				     const Standard_Real v2,
				     gp_Pnt& P) { 
  gp_Pnt aP;
  gp_Vec aT;
  gp_Vec2d aTS1,aTS2;
  Standard_Real tu1=u1;
  Standard_Real tu2=u2;
  Standard_Real tv1=v1;
  Standard_Real tv2=v2;
  this->Compute(tu1,tv1,tu2,tv2,aP,aT,aTS1,aTS2);
  P=MyPnt;
}
//--------------------------------------------------------------------------------
Standard_Boolean ApproxInt_PrmPrmSvSurfaces::Tangency(const Standard_Real u1,
						      const Standard_Real v1,
						      const Standard_Real u2,
						      const Standard_Real v2,
						      gp_Vec& T) { 
  gp_Pnt aP;
  gp_Vec aT;
  gp_Vec2d aTS1,aTS2;
  Standard_Real tu1=u1;
  Standard_Real tu2=u2;
  Standard_Real tv1=v1;
  Standard_Real tv2=v2;
  Standard_Boolean t=this->Compute(tu1,tv1,tu2,tv2,aP,aT,aTS1,aTS2);
  T=MyTg;
  return(t);
}
//--------------------------------------------------------------------------------
Standard_Boolean ApproxInt_PrmPrmSvSurfaces::TangencyOnSurf1(const Standard_Real u1,
							     const Standard_Real v1,
							     const Standard_Real u2,
							     const Standard_Real v2,
							     gp_Vec2d& T) { 
  gp_Pnt aP;
  gp_Vec aT;
  gp_Vec2d aTS1,aTS2;
  Standard_Real tu1=u1;
  Standard_Real tu2=u2;
  Standard_Real tv1=v1;
  Standard_Real tv2=v2;
  Standard_Boolean t=this->Compute(tu1,tv1,tu2,tv2,aP,aT,aTS1,aTS2);
  T=MyTguv1;
  return(t);
}
//--------------------------------------------------------------------------------
Standard_Boolean ApproxInt_PrmPrmSvSurfaces::TangencyOnSurf2(const Standard_Real u1,
							     const Standard_Real v1,
							     const Standard_Real u2,
							     const Standard_Real v2,
							     gp_Vec2d& T) { 
  gp_Pnt aP;
  gp_Vec aT;
  gp_Vec2d aTS1,aTS2;
  Standard_Real tu1=u1;
  Standard_Real tu2=u2;
  Standard_Real tv1=v1;
  Standard_Real tv2=v2;
  Standard_Boolean t=this->Compute(tu1,tv1,tu2,tv2,aP,aT,aTS1,aTS2);
  T=MyTguv2;
  return(t);
}
//--------------------------------------------------------------------------------




#if 0 
  //------------------------------------------------------------
  //-- Calcul de Tguv1
  //--
  ThePSurfaceTool::D1(MySurf1,u1,v1,P,TU,TV);
  
  TUTV = TU.Dot(TV);
  TgTU = Tg.Dot(TU);
  TgTV = Tg.Dot(TV);
  UmTUTV2 = 1.0 - TUTV * TUTV;
  
  DeltaU = (TgTU - TgTV * TUTV ) / UmTUTV2 ; 
  DeltaV = (TgTV - TgTU * TUTV ) / UmTUTV2 ;

  Delta = 1.0 / Sqrt(DeltaU * DeltaU + DeltaV * DeltaV);
  
  Tguv1.Multiplied(Delta);  MyTguv1 = Tguv1;

  //------------------------------------------------------------
  //-- Calcul de Tguv2
  //--  
  ThePSurfaceTool::D1(MySurf2,u2,v2,P,TU,TV);

  TUTV = TU.Dot(TV);
  TgTU = Tg.Dot(TU);
  TgTV = Tg.Dot(TV);
  UmTUTV2 = 1.0 - TUTV * TUTV;
  
  DeltaU = (TgTU - TgTV * TUTV ) / UmTUTV2 ; 
  DeltaV = (TgTV - TgTU * TUTV ) / UmTUTV2 ;
  
  Delta = 1.0 / Sqrt(DeltaU * DeltaU + DeltaV * DeltaV);
  
  Tguv2.Multiplied(Delta);  MyTguv2 = Tguv2;

  return(Standard_True);
}
#endif