// This code implementation is the intellectual property of
// the GEANT4 collaboration.
//
// By copying, distributing or modifying the Program (or any work
// based on the Program) you indicate your acceptance of this statement,
// and all its terms.
//
// $Id: G4Torus.hh,v 1.5 2000/05/26 13:20:40 grichine Exp $
// GEANT4 tag $Name: geant4-02-00 $
//
// 
// --------------------------------------------------------------------
// GEANT 4 class header file
//
// G4Torus
//
// Class description:
//
//   A torus or torus segment with curved sides parallel to the z-axis.
//   The torus has a specified swept radius about which it is centered,
//   and a given minimum and maximum radius. A minimum radius of 0
//   signifies a filled torus.
//   The torus segment is specified by starting and delta angles for phi,
//   with 0 being the +x axis, PI/2 the +y axis. A delta angle of 2PI
//   signifies a complete, unsegmented torus/cylindr.
//
//   Member functions:
//
//   As inherited from G4CSGSolid+
//
//     G4Torus(const G4String      &pName
//             G4double      pRmin
//             G4double      pRmax
//             G4double      pRtor
//             G4double      pSPhi
//             G4double      pDPhi )
//
//     - Construct a torus with the given name and dimensions.
//       The angles are provided is radians. pRtor >= pRmax
//
//
//   Protected:
//
//     G4ThreeVectorList*
//     CreateRotatedVertices(const G4AffineTransform& pTransform) const
//
//     - Create the List of transformed vertices in the format required
//       for G4VSolid:: ClipCrossSection and ClipBetweenSections.
//   
//   Member Data:
//
//	fRmin	Inside radius
//	fRmax	Outside radius
//	fRtor	swept radius of torus
//
//	fSPhi	The starting phi angle in radians,
//              adjusted such the fSPhi+fDPhi<=2PI,
//              fSPhi>-2PI
//
//	fDPhi	Delta angle of the segment in radians
//
//   You could find very often in G4Torus:: functions the values like pt or
//   it . These are the distances from p or i G4ThreeVector points in the
//   plane (Z axis points p or i) to fRtor point in XY plane. This value is
//   similar to rho for G4Tubs and is used for definiton of the point
//   relative to fRmin and fRmax, i.e. for solution of inside/outside
//   problems
 
// History:
// 30.10.96 V.Grichine     First version of G4Torus
// 21.04.98 J.Apostolakis  Added SetAllParameters function
// 26.05.00 V.Grichine, new SolveBiQuadratic/Cubic developed by O.Cremonesi were
//          added     
// --------------------------------------------------------------------

#ifndef G4Torus_HH
#define G4Torus_HH

#include "G4CSGSolid.hh"

class G4Torus : public G4CSGSolid {
public:
G4Torus(const G4String &pName,
	  G4double pRmin,
	  G4double pRmax,
	  G4double pRtor,
	  G4double pSPhi,
	  G4double pDPhi);

    virtual ~G4Torus();
    
    void SetAllParameters(G4double pRmin, G4double pRmax, G4double pRtor,
	       G4double pSPhi, G4double pDPhi);
 
    void ComputeDimensions(G4VPVParameterisation* p,
                           const G4int n,
                           const G4VPhysicalVolume* pRep);
			   
    G4int TorusRoots(G4double Ri,
		     const G4ThreeVector& p,
		     const G4ThreeVector& v) const ;

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

    G4double    GetRmin() const { return fRmin ; }
    G4double    GetRmax() const { return fRmax ; } 
    G4double    GetRtor  () const { return fRtor   ; }
    G4double    GetSPhi() const { return fSPhi ; }
    G4double    GetDPhi() const { return fDPhi ; }

    EInside Inside(const G4ThreeVector& p) const;

    G4ThreeVector SurfaceNormal( const G4ThreeVector& p) const;

    G4double DistanceToIn(const G4ThreeVector& p,const G4ThreeVector& v) const;
    G4double DistanceToIn(const G4ThreeVector& p) const;
    G4double DistanceToOut(const G4ThreeVector& p,const G4ThreeVector& v,
			   const G4bool calcNorm=G4bool(false),
			   G4bool *validNorm=0,G4ThreeVector *n=0) const;
    G4double DistanceToOut(const G4ThreeVector& p) const;

    // Naming method (pseudo-RTTI : run-time type identification)
    virtual G4GeometryType  GetEntityType() const { return G4String("G4Torus"); }

    // Visualisation functions
    void                DescribeYourselfTo (G4VGraphicsScene& scene) const;
    G4Polyhedron*       CreatePolyhedron   () const;
    G4NURBS*            CreateNURBS        () const;

protected:

    G4int SolveBiQuadratic(G4double c[], G4double s[]  ) const ;
    G4int SolveCubic(G4double c[], G4double s[]  ) const ;

    G4int SolveBiQuadraticNew(G4double c[], G4double s[]  ) const ;
    G4int SolveCubicNew(G4double c[], G4double s[], G4double& cd  ) const ;

    G4int SolveQuadratic(double c[], double s[]  ) const ;
    
    G4ThreeVectorList*
    CreateRotatedVertices(const G4AffineTransform& pTransform,
                          G4int& noPolygonVertices) const;

    G4double fRmin,fRmax,fRtor,fSPhi,fDPhi;

  // Used by distanceToOut
  enum ESide {kNull,kRMin,kRMax,kSPhi,kEPhi};
  // used by normal
  enum ENorm {kNRMin,kNRMax,kNSPhi,kNEPhi};

};
   	
#endif