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// $Id$
//
// 
// --------------------------------------------------------------------
// GEANT 4 class header file
//
//
// G4PolyPhiFace
//
// Class description:
//
//   Definition of a face that bounds a polycone or polyhedra when
//   it has a phi opening:
//
//   G4PolyPhiFace( const G4ReduciblePolygon *rz,
//                        G4double phi,
//                        G4double deltaPhi,
//                        G4double phiOther )
//
//   Specifically: a face that lies on a plane that passes through
//   the z axis. It has boundaries that are straight lines of arbitrary
//   length and direction, but with corners aways on the same side of
//   the z axis.

// Author: 
//   David C. Williams (davidw@scipp.ucsc.edu)
// --------------------------------------------------------------------

#ifndef G4PolyPhiFace_hh
#define G4PolyPhiFace_hh

#include "G4VCSGface.hh"
#include "G4TwoVector.hh"

class G4ReduciblePolygon;

struct G4PolyPhiFaceVertex
{
  G4double x, y, r, z;   // position
  G4double rNorm, 
           zNorm;        // r/z normal
  G4ThreeVector norm3D;  // 3D normal

  // Needed for Triangulation Algorithm
  //
  G4bool ear;
  G4PolyPhiFaceVertex *next,*prev;
};

struct G4PolyPhiFaceEdge
{
  G4PolyPhiFaceEdge(): v0(0), v1(0), tr(.0), tz(0.), length(0.) {}
  G4PolyPhiFaceVertex  *v0, *v1;  // Corners
  G4double tr, tz,                // Unit vector along edge
           length;                // Length of edge
  G4ThreeVector norm3D;           // 3D edge normal vector
};

class G4PolyPhiFace : public G4VCSGface
{

  public:  // with description

    G4PolyPhiFace( const G4ReduciblePolygon *rz,
                         G4double phi, G4double deltaPhi, G4double phiOther );
      // Constructor.
      // Points r,z should be supplied in clockwise order in r,z.
      // For example:
      //                [1]---------[2]         ^ R
      //                 |           |          |
      //                 |           |          +--> z
      //                [0]---------[3]

    virtual ~G4PolyPhiFace();
      // Destructor. Removes edges and corners.

    G4PolyPhiFace( const G4PolyPhiFace &source );
    G4PolyPhiFace& operator=( const G4PolyPhiFace &source );
      // Copy constructor and assgnment operator.

    G4bool Intersect( const G4ThreeVector &p, const G4ThreeVector &v,
                            G4bool outgoing, G4double surfTolerance,
                            G4double &distance, G4double &distFromSurface,
                            G4ThreeVector &normal, G4bool &allBehind );

    G4double Distance( const G4ThreeVector &p, G4bool outgoing );
  
    EInside Inside( const G4ThreeVector &p, G4double tolerance, 
                          G4double *bestDistance );
    
    G4ThreeVector Normal( const G4ThreeVector &p, G4double *bestDistance );

    G4double Extent( const G4ThreeVector axis );
  
    void CalculateExtent( const EAxis axis, 
                          const G4VoxelLimits &voxelLimit,
                          const G4AffineTransform &tranform,
                                G4SolidExtentList &extentList );

    inline G4VCSGface *Clone();
      // Allocates on the heap a clone of this face.

    G4double SurfaceArea();
    G4double SurfaceTriangle( G4ThreeVector p1, G4ThreeVector p2,
                              G4ThreeVector p3, G4ThreeVector* p4);
    G4ThreeVector GetPointOnFace();
      // Auxiliary methods for determination of points on surface.

  public:  // without description

    G4PolyPhiFace(__void__&);
      // Fake default constructor for usage restricted to direct object
      // persistency for clients requiring preallocation of memory for
      // persistifiable objects.

    void Diagnose( G4VSolid *solid );
      // Throw an exception if something is found inconsistent with
      // the solid. For debugging purposes only

  protected:

    G4bool InsideEdgesExact( G4double r, G4double z, G4double normSign,
                             const G4ThreeVector &p, const G4ThreeVector &v );
      // Decide if the point in r,z is inside the edges of our face,
      // **but** do so consistently with other faces.

    G4bool InsideEdges( G4double r, G4double z );
    G4bool InsideEdges( G4double r, G4double z, G4double *distRZ2,
                        G4PolyPhiFaceVertex **base3Dnorm=0,
                        G4ThreeVector **head3Dnorm=0 );
      // Decide if the point in r,z is inside the edges of our face.

    inline G4double ExactZOrder( G4double z, 
                                 G4double qx, G4double qy, G4double qz, 
                           const G4ThreeVector &v, 
                                 G4double normSign,
                           const G4PolyPhiFaceVertex *vert ) const;
      // Decide precisely whether a trajectory passes to the left, right,
      // or exactly passes through the z position of a vertex point in face.

    void CopyStuff( const G4PolyPhiFace &source );

  protected:

    // Functions used for Triangulation in Case of generic Polygone.
    // The triangulation is used for GetPointOnFace()

    G4double Area2( G4TwoVector a, G4TwoVector b, G4TwoVector c);
      // Calculation of 2*Area of Triangle with Sign

    G4bool Left( G4TwoVector a, G4TwoVector b, G4TwoVector c );
    G4bool LeftOn( G4TwoVector a, G4TwoVector b, G4TwoVector c );
    G4bool Collinear( G4TwoVector a, G4TwoVector b, G4TwoVector c );
      // Boolean functions for sign of Surface

    G4bool IntersectProp( G4TwoVector a, G4TwoVector b,
                          G4TwoVector c, G4TwoVector d );
      // Boolean function for finding proper intersection of two
      // line segments (a,b) and (c,d).

    G4bool Between( G4TwoVector a, G4TwoVector b, G4TwoVector c );
      // Boolean function for determining if point c is between a and b
      // where the three points (a,b,c) are on the same line.

    G4bool Intersect( G4TwoVector a, G4TwoVector b,
                      G4TwoVector c, G4TwoVector d );
      // Boolean function for finding proper intersection or not
      // of two line segments (a,b) and (c,d).

    G4bool Diagonalie( G4PolyPhiFaceVertex *a, G4PolyPhiFaceVertex *b );
      // Boolean Diagonalie help to determine if diagonal s
      // of segment (a,b) is convex or reflex.

    G4bool InCone( G4PolyPhiFaceVertex *a, G4PolyPhiFaceVertex *b );
      // Boolean function for determining if b is inside the cone (a0,a,a1)
      // where a is the center of the cone.

    G4bool Diagonal( G4PolyPhiFaceVertex *a, G4PolyPhiFaceVertex *b );
      // Boolean function for determining if Diagonal is possible
      // inside Polycone or PolyHedra.

    void EarInit();
      // Initialisation for Triangulisation by ear tips.
      // For details see "Computational Geometry in C" by Joseph O'Rourke.

    void Triangulate();
      // Triangularisation by ear tips for Polycone or Polyhedra.
      // For details see "Computational Geometry in C" by Joseph O'Rourke.
      // NOTE: a copy of the shape is made and this copy is reordered in
      //       order to have a list of triangles. This list is used by the
      //       method GetPointOnFace().

  protected:

    G4int      numEdges;            // Number of edges
    G4PolyPhiFaceEdge   *edges;     // The edges of the face
    G4PolyPhiFaceVertex *corners;   // And the corners
    G4ThreeVector    normal;        // Normal unit vector
    G4ThreeVector    radial;        // Unit vector along radial direction
    G4ThreeVector    surface;       // Point on surface
    G4ThreeVector    surface_point; // Auxiliary point on surface used for
                                    // method GetPointOnFace() 
    G4double   rMin, rMax, // Extent in r
               zMin, zMax; // Extent in z
    G4bool      allBehind; // True if the polycone/polyhedra
                           // is behind the place of this face
    G4double   kCarTolerance;// Surface thickness
    G4double   fSurfaceArea; // Surface Area of PolyPhiFace 
    G4PolyPhiFaceVertex *triangles; // Auxiliary pointer to 'corners' used for
                                    // triangulation. Copy structure, changing
                                    // the structure of 'corners' (ear removal)
};

#include "G4PolyPhiFace.icc"

#endif
