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//
// G4EllipticalTube
//
// Class description:
//
//   Declaration of a CSG volume representing a tube with elliptical
//   cross section (geant3 solid 'ELTU'):
//
//   G4EllipticalTube( const G4String& name,
//                           G4double  Dx,
//                           G4double  Dy,
//                           G4double  Dz )
//
//   The equation of the lateral surface : (x/dx)^2 + (y/dy)^2 = 1

// Author: David C. Williams (davidw@scipp.ucsc.edu)
// Revision: Evgueni Tcherniaev (evgueni.tcherniaev@cern.ch), 23.12.2019
// --------------------------------------------------------------------
#ifndef G4ELLIPTICALTUBE_HH
#define G4ELLIPTICALTUBE_HH

#include "G4GeomTypes.hh"

#if defined(G4GEOM_USE_USOLIDS)
#define G4GEOM_USE_UELLIPTICALTUBE 1
#endif

#if (defined(G4GEOM_USE_UELLIPTICALTUBE) && defined(G4GEOM_USE_SYS_USOLIDS))
  #define G4UEllipticalTube G4EllipticalTube
  #include "G4UEllipticalTube.hh"
#else

#include "G4VSolid.hh"
#include "G4Polyhedron.hh"

class G4EllipticalTube : public G4VSolid
{
  public:

    G4EllipticalTube( const G4String& name,
                            G4double Dx,
                            G4double Dy,
                            G4double Dz );

    ~G4EllipticalTube() override;

    // Standard methods
    //
    void BoundingLimits(G4ThreeVector& pMin, G4ThreeVector& pMax) const override;

    G4bool CalculateExtent(const EAxis pAxis,
                           const G4VoxelLimits& pVoxelLimit,
                           const G4AffineTransform& pTransform,
                                 G4double& pmin, G4double& pmax) const override;

    EInside Inside( const G4ThreeVector& p ) const override;

    G4ThreeVector SurfaceNormal( const G4ThreeVector& p ) const override;

    G4double DistanceToIn( const G4ThreeVector& p,
                           const G4ThreeVector& v ) const override;

    G4double DistanceToIn( const G4ThreeVector& p ) const override;

    G4double DistanceToOut( const G4ThreeVector& p,
                            const G4ThreeVector& v,
                            const G4bool calcNorm = false,
                                  G4bool* validNorm = nullptr,
                                  G4ThreeVector* n = nullptr ) const override;

    G4double DistanceToOut( const G4ThreeVector& p ) const override;

    G4GeometryType GetEntityType() const override;

    G4VSolid* Clone() const override;

    std::ostream& StreamInfo(std::ostream& os) const override;

    G4double GetCubicVolume() override;
    G4double GetSurfaceArea() override;

    G4ThreeVector GetPointOnSurface() const override;

    // Visualisation methods
    //
    G4Polyhedron* CreatePolyhedron() const override;
    G4Polyhedron* GetPolyhedron () const override;
    void DescribeYourselfTo( G4VGraphicsScene& scene ) const override;
    G4VisExtent GetExtent() const override;

    // Accessors
    //
    inline G4double GetDx() const;
    inline G4double GetDy() const;
    inline G4double GetDz() const;
  
    inline void SetDx( G4double Dx );
    inline void SetDy( G4double Dy );
    inline void SetDz( G4double Dz );
 
    G4EllipticalTube(__void__&);
      // Fake default constructor for usage restricted to direct object
      // persistency for clients requiring preallocation of memory for
      // persistifiable objects

    G4EllipticalTube(const G4EllipticalTube& rhs);
    G4EllipticalTube& operator=(const G4EllipticalTube& rhs);
      // Copy constructor and assignment operator

  private:

    void CheckParameters();
      // Check parameters and set pre-calculated values

    G4ThreeVector ApproxSurfaceNormal( const G4ThreeVector& p ) const;
      // Algorithm for SurfaceNormal() following the original
      // specification for points not on the surface

    G4double GetCachedSurfaceArea() const;
      // Calculate surface area and cache it

  private:

    G4double halfTolerance;

    G4double fDx; // semi-axis in X
    G4double fDy; // semi-axis in Y
    G4double fDz; // half length in Z

    G4double fCubicVolume = 0.0; // volume
    G4double fSurfaceArea = 0.0; // surface area  

    // Cached pre-calculated values
    G4double fRsph;    // R of bounding sphere
    G4double fDDx;     // Dx squared
    G4double fDDy;     // Dy squared
    G4double fSx;      // X scale factor
    G4double fSy;      // Y scale factor
    G4double fR;       // resulting Radius, after scaling elipse to circle
    G4double fQ1;      // distance approximation : dist = Q1*(x^2 + y^2) - Q2
    G4double fQ2;      // distance approximation : dist = Q1*(x^2 + y^2) - Q2
    G4double fScratch; // half length of scratching segment squared

    mutable G4bool fRebuildPolyhedron = false;
    mutable G4Polyhedron* fpPolyhedron = nullptr;
};

#include "G4EllipticalTube.icc"

#endif  // defined(G4GEOM_USE_UELLIPTICALTUBE) && defined(G4GEOM_USE_SYS_USOLIDS)

#endif // G4ELLIPTICALTUBE_HH