source: trunk/source/geometry/solids/BREPS/include/G4Line.icc@ 1315

//
// ********************************************************************
// * License and Disclaimer                                           *
// *                                                                  *
// * The  Geant4 software  is  copyright of the Copyright Holders  of *
// * the Geant4 Collaboration.  It is provided  under  the terms  and *
// * conditions of the Geant4 Software License,  included in the file *
// * LICENSE and available at  http://cern.ch/geant4/license .  These *
// * include a list of copyright holders.                             *
// *                                                                  *
// * Neither the authors of this software system, nor their employing *
// * institutes,nor the agencies providing financial support for this *
// * work  make  any representation or  warranty, express or implied, *
// * regarding  this  software system or assume any liability for its *
// * use.  Please see the license in the file  LICENSE  and URL above *
// * for the full disclaimer and the limitation of liability.         *
// *                                                                  *
// * This  code  implementation is the result of  the  scientific and *
// * technical work of the GEANT4 collaboration.                      *
// * By using,  copying,  modifying or  distributing the software (or *
// * any work based  on the software)  you  agree  to acknowledge its *
// * use  in  resulting  scientific  publications,  and indicate your *
// * acceptance of all terms of the Geant4 Software license.          *
// ********************************************************************
//
//
// $Id: G4Line.icc,v 1.10 2008/03/13 14:18:57 gcosmo Exp $
// GEANT4 tag $Name: geant4-09-03 $
//
// --------------------------------------------------------------------
// GEANT 4 inline definitions file
//
// G4Line.icc
//
// Implementation of inline methods of G4Line
// --------------------------------------------------------------------

inline
G4double G4Line::GetPMax() const
{
  return -1;
}

inline
G4Point3D G4Line::GetPoint(G4double param) const
{
  return G4Point3D( pnt+param*dir );
}

inline
G4double G4Line::GetPPoint(const G4Point3D& pt) const
{ 
  return (pt-pnt)*invDir; 
}

////////////////////////////////////////////////////////////////////////////

inline
void G4Line::Init(const G4Point3D& pnt0, const G4Vector3D& dir0)
{
  pnt= pnt0;
  dir= dir0;
  invDir= dir*(1/dir.mag2());
  v= dir.unit();
}

inline
G4Point3D G4Line::GetPnt() const
{
  return pnt;
}

inline
G4Vector3D G4Line::GetDir() const
{
  return dir;
}

///////////////////////////////////////////////////////////////////////////

inline
void G4Line::InitBounded()
{
  bBox.Init(GetStart(), GetEnd());
}

///////////////////////////////////////////////////////////////////////////

#include "G4CurveRayIntersection.hh"

/*
inline
void G4Line::IntersectRay2D(const G4Ray& ray,
                            G4CurveRayIntersection& is)
{
  is.Init(*this, ray);
  G4CurveRayIntersection isTmp(*this, ray);

  const G4Point3D& s= ray.GetStart();
  const G4Vector3D& d= ray.GetDir();

  G4double num= (s.x()-pnt.x())*v.y()-(s.y()-pnt.y())*v.x();
  G4double denom= d.y()*v.x()-d.x()*v.y();
  
  if (denom < kAngTolerance) {
    if (num < kCarTolerance) {

      // identical lines
      isTmp.ResetDistance(kCarTolerance);
      is.Update(isTmp);
      isTmp.Reset(GetPStart(), GetStart());
      is.UpdateWithPointOnCurve(isTmp);
      isTmp.Reset(GetPEnd(), GetEnd());
      is.UpdateWithPointOnCurve(isTmp);

    } else {

      // parallel lines

    }
  } else {

    // properly intersecting lines
    isTmp.ResetDistance(num/denom);
    is.Update(isTmp);

  }
}
*/

inline
G4int G4Line::IntersectRay2D(const G4Ray& ray)
{
  const G4Point3D& s= ray.GetStart();
  const G4Vector3D& d= ray.GetDir();

  G4double num1= (pnt.x()-s.x())*d.y()-(pnt.y()-s.y())*d.x();
  G4double num2= (pnt.x()-s.x())*dir.y()-(pnt.y()-s.y())*dir.x();
  G4double denom= d.x()*dir.y()-d.y()*dir.x();
  
  G4int nbinter = 0;

  if (std::fabs(denom) < kCarTolerance) 
  {
    if (std::fabs(num1) < kCarTolerance) 
    {
      // identical lines
    } 
    else 
    {
      // parallel lines
    }
  } 
  else
  {
    // properly intersecting lines
    G4double u = num1/denom;
    G4double t = num2/denom;

    if( (u > -kCarTolerance/2) && (u < kCarTolerance/2) )
      u = 0;

    if( (t > -kCarTolerance/2) && (t < kCarTolerance/2) )
      t = 0;
    
    // test the validity of the results 
    if(t>=0 && u>=0 && u<=1)
    {
      // test if the point is on the line
      if( t==0 || u==0 )
        return 999;
      else      
        nbinter = 1;
    }
  }
  
  return nbinter;
}