//-----------------------------------------------------------------------------
// Jan 13 2001 P.Murat: stolen from Joe in exchange for trybos bank
//-----------------------------------------------------------------------------
#ifndef TLine3D_hh
#define TLine3D_hh

#include "TVector3.h"

#include "TTrajectory3D.hh"

class TTrajectoryPoint;

class TLine3D : public TTrajectory3D {
public:
					// ****** constructors and destructor
  TLine3D();
  TLine3D(const TLine3D &right);
  TLine3D(const TVector3 &point, const TVector3 &direction);
  ~TLine3D();
  
  void  Init(const TVector3 &point, const TVector3 &direction);

					// point is x,y,z,nx,ny,nz,ptot

  void  Init(TTrajectoryPoint* point);

  const TLine3D & operator=(const TLine3D &right);
  
					// Position

  virtual void GetPosition(TVector3& pos, double s = 0.0) const;
  
					// Direction

  virtual void GetDirection(TVector3& dir, double s = 0.0) const;

					// Parameters.

  double getD0      () const { return _d0; }
  double getZ0      () const { return _z0; }
  double getPhi0    () const { return _phi0; }
  double getCotTheta() const { return _sinTheta==0 ? 0:_cosTheta/_sinTheta; }

					// Position and direction together

  virtual void GetLocation(TTrajectory3D::Location & loc, double s = 0.0) const;

  void GetPoint     (TTrajectoryPoint* point, double s = 0.0) const;

					// pathlength at specifed distance 
					// from z-axis

  virtual double GetPathLengthAtRho(double rho) const;
  virtual double GetPathLengthAtZ  (double Z  ) const;

					// Second deiviative

  virtual TVector3 getSecondDerivative(double s = 0.0) const;
  
					// This is to keep the base class 
					// methods from being hidden

  virtual double getPathLengthTo(const TTrajectory3D &t) const {
    return TTrajectory3D::getPathLengthTo(t);
  }

  virtual double getDzeroTo(const TTrajectory3D &t) const {
    return TTrajectory3D::getDzeroTo(t);
  }
					// Pathlength to point

  virtual double getPathLengthTo(const TVector3 &point) const;
  
					// DZero to point

  virtual double getDzeroTo(const TVector3 &point) const;
                  
					// Pathlength to line

  virtual double getPathLengthTo(const TLine3D & line);

					// DZero to line

  virtual double getDzeroTo(const TLine3D &line);

					// Intersection with a plane
					// temporarily disabled

  //  virtual TTrajectory3D::Location * newIntersectionWith(const HepPlane3D &plane) const; 

  private:

      double _sinTheta;
      double _cosTheta;
      double _z0;
      double _d0;
      double _phi0;
      double _sinPhi0;
      double _cosPhi0;

  ClassDef(TLine3D,1)
};





#endif