//=============================================================================
//
//  File:      SlantedTubeSection.cpp
//  Created:   13-FEB-1998 by Stephen Kahn
//  Purpose:   provide SlantedTubeSection methods
//
//============================================================================
#include <cmath>
#include <geometry_system/components/SlantedTubeSection.hpp>
#include <geometry_system/components/CartesianCoordinate.hpp>
extern "C" {
  double hypot(double,double);
}

using namespace dgs;
using namespace std;

//
//  fill_TubularSection
//
void  SlantedTubeSection::fill_SlantedTubeSection( const double dz, 
						   const double ri, 
				       const double ro, const double phi1,
				       const double phi2, const double slt_ang)
  {  
     TubularSection::fill_TubularSection( dz, ri, ro, phi1, phi2);
     _slant_angle = slt_ang;
     _tan_slant_angle = tan(_slant_angle);
  }
//
//   zeta_from_cylind
//
double  SlantedTubeSection::zeta_from_cylind( double r, double z)
{
  double  rcen;
  CartesianCoordinate cent;
  double  zeta;

  cent = get_center();
  rcen = hypot( cent.x(), cent.y());
  zeta = z - cent.z() + (r - rcen)*_tan_slant_angle;
  return zeta;
}
//
//   local to cartesian
//
CartesianCoordinate  SlantedTubeSection::local_to_cartesian( double r, 
					 double zeta, double phi)
{  double x, y, z;
   double xl, yl, zl, phic, rcen;
   CartesianCoordinate cent;

   cent = get_center();
   rcen = hypot( cent.x(), cent.y());
   phic = atan2( cent.y(), cent.x());

   x = r*cos(phi) - rcen;
   y = r*sin(phi);
   z = zeta - (r - rcen)*_tan_slant_angle;

   xl = x*cos(phic) + y*sin(phic);
   yl = -x*sin(phic) + y*cos(phic);
   zl = z - cent.z();

   CartesianCoordinate pos( xl, yl, zl);

   return pos;
}