// File:	Extrema_GenLocateExtCC.gxx
// Created:	Tue Jul 18 17:43:58 1995
// Author:	Modelistation
//		<model@metrox>

#include <StdFail_NotDone.hxx>
#include <math_FunctionSetRoot.hxx>
#include <math_Vector.hxx>

//=============================================================================
Extrema_GenLocateExtCC::Extrema_GenLocateExtCC (const Curve1& C1,
					  const Curve2& C2,
					  const Standard_Real U0, const Standard_Real V0,
					  const Standard_Real TolU, const Standard_Real TolV)
/*-----------------------------------------------------------------------------
Fonction:
  Recherche du couple de valeurs de parametre (U,V) tel que:
  - dist(C1(u),C2(v)) passe par un extremum,
  - (U,V) soit la solution la plus proche de (U0,V0).

Methode:
  Si (u,v) est solution, alors:
   { F1(u,v)=(C1(u)-C2(v)).dC1/du(u) = 0.
   { F2(u,v)=(C1(u)-C2(v)).dC2/dv(v) = 0.
  Le probleme consiste a rechercher, dans les intervalles de definition
  des courbes, la racine du systeme la plus proche de (U0,V0).
  On utilise la classe math_FunctionSetRoot avec les arguments de construction
  suivants:
  - F: Extrema_FuncExtCC cree a partir de C1 et C2,
  - math_Vector(U0,V0),
  - math_Vector(TolU,TolV),
  - math_Vector(Uinf,Usup),
  - math_Vector(Vinf,Vsup),
  - 100. .
-----------------------------------------------------------------------------*/
{
  myDone = Standard_False;

  Standard_Real Uinf = Tool1::FirstParameter(C1);
  Standard_Real Usup = Tool1::LastParameter(C1);
  Standard_Real Uu;
  if (Uinf>Usup) {
     Uu=Uinf;
     Uinf=Usup;
     Usup =Uu;
  }

  Standard_Real Vinf = Tool2::FirstParameter(C2);
  Standard_Real Vsup = Tool2::LastParameter(C2);
  if (Vinf>Vsup) {
     Uu=Vinf;
     Vinf=Vsup;
     Vsup =Uu;
  }

  Extrema_CCLocF F (C1,C2);
  math_Vector Tol(1, 2);
  Tol(1) = TolU;
  Tol(2) = TolV;
  Standard_Real Tolf = 1.e-10;

  math_Vector Start(1,2);
  math_Vector Uuinf(1,2);
  math_Vector Uusup(1,2);

  Start(1) = U0;
  Start(2) = V0;

  Uuinf(1)=Uinf;
  Uuinf(2)=Vinf;
  Uusup(1)=Usup;
  Uusup(2)=Vsup;

  math_FunctionSetRoot S (F,Start,Tol,Uuinf,Uusup);
  if (S.IsDone() && F.NbExt() > 0) { 
    mySqDist = F.SquareDistance(1);
    F.Points(1,myPoint1,myPoint2);
    Start(1)=myPoint1.Parameter();
    Start(2)=myPoint2.Parameter();
    math_Vector Ff(1,2);
    F.Value(Start,Ff);
//    cout << "Ff(1) = "<<Ff(1)<<endl;
//    cout << "Ff(2) = "<<Ff(2)<<endl;
    if ((Ff(1)<Tolf) && (Ff(2)<Tolf) ) myDone = Standard_True;
  }
}
//=============================================================================

Standard_Boolean Extrema_GenLocateExtCC::IsDone () const { return myDone; }
//=============================================================================

Standard_Real Extrema_GenLocateExtCC::SquareDistance() const
{
  if (!IsDone()) { StdFail_NotDone::Raise(); }
  return mySqDist;
}
//=============================================================================

void Extrema_GenLocateExtCC::Point (POnC& P1, POnC& P2)
     const
{
  if (!IsDone()) { StdFail_NotDone::Raise(); }
  P1 = myPoint1;
  P2 = myPoint2;
}
//=============================================================================