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// $Id: G4TriangularFacet.hh,v 1.8 2007/12/10 16:30:18 gunter Exp $
// GEANT4 tag $Name: geant4-09-04-beta-01 $
//
// %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
//
// MODULE:              G4TriangularFacet.hh
//
// Date:                15/06/2005
// Author:              P R Truscott
// Organisation:        QinetiQ Ltd, UK
// Customer:            UK Ministry of Defence : RAO CRP TD Electronic Systems
// Contract:            C/MAT/N03517
//
// %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
//
// CHANGE HISTORY
// --------------
//
// 31 October 2004, P R Truscott, QinetiQ Ltd, UK - Created.
//
// %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
//
// Class description:
//
//   The G4TriangularFacet class is used for the contruction of
//   G4TessellatedSolid.
//   It is defined by three vertices, which shall be supplied in anti-clockwise
//   order looking from the outsider of the solid where it belongs.
//   Its constructor:
//   
//      G4TriangularFacet (const G4ThreeVector Pt0, const G4ThreeVector vt1,
//                         const G4ThreeVector vt2, G4FacetVertexType);
//
//   takes 4 parameters to define the three vertices:
//      1) G4FacetvertexType = "ABSOLUTE": in this case Pt0, vt1 and vt2 are 
//         the 3 vertices in anti-clockwise order looking from the outsider.
//      2) G4FacetvertexType = "RELATIVE": in this case the first vertex is Pt0,
//         the second vertex is Pt0+vt1 and the third vertex is Pt0+vt2, all  
//         in anti-clockwise order when looking from the outsider.

///////////////////////////////////////////////////////////////////////////////
#ifndef G4TriangularFacet_hh
#define G4TriangularFacet_hh 1

#include "globals.hh"
#include "G4VFacet.hh"
#include "G4ThreeVector.hh"
#include "G4TessellatedGeometryAlgorithms.hh"

class G4TriangularFacet : public G4VFacet
{
  public:  // with description

    G4TriangularFacet (const G4ThreeVector Pt0, const G4ThreeVector vt1,
                       const G4ThreeVector vt2, G4FacetVertexType);
    ~G4TriangularFacet ();
    
    G4TriangularFacet (const G4TriangularFacet &right);
    const G4TriangularFacet &operator=(G4TriangularFacet &right);    

    G4VFacet *GetClone ();
    G4TriangularFacet *GetFlippedFacet ();
    
    G4ThreeVector Distance (const G4ThreeVector &p);
    G4double Distance (const G4ThreeVector &p, const G4double minDist);
    G4double Distance (const G4ThreeVector &p, const G4double minDist,
                       const G4bool outgoing);
    G4double Extent   (const G4ThreeVector axis);
    G4bool Intersect  (const G4ThreeVector &p, const G4ThreeVector &v,
                       const G4bool outgoing, G4double &distance,
                             G4double &distFromSurface, G4ThreeVector &normal);
    G4double GetArea ();
    G4ThreeVector GetPointOnFace () const;

  private:

    G4double a;
    G4double b;
    G4double c;
    G4double det;
    
    G4double sMin, sMax;
    G4double tMin;

    G4double sqrDist;

    G4TessellatedGeometryAlgorithms *tGeomAlg;
};

#endif