G4ClippablePolygon.hh

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// G4ClippablePolygon
//
// Class description:
//
// Declaration of a utility class of a polygon that can be
// clipped by a voxel.

// Author: David C. Williams (davidw@scipp.ucsc.edu)
// --------------------------------------------------------------------
#ifndef G4CLIPPABLEPOLYGON_HH
#define G4CLIPPABLEPOLYGON_HH

#include <vector>

#include "G4Types.hh"
#include "geomdefs.hh"
#include "G4ThreeVector.hh"

class G4AffineTransform;
class G4VoxelLimits;

class G4ClippablePolygon
{
  typedef std::vector<G4ThreeVector> G4ThreeVectorList;

  public:  // with description

  G4ClippablePolygon();
  virtual ~G4ClippablePolygon();
    // Constructor & virtual destructor.
  
  virtual void AddVertexInOrder( const G4ThreeVector vertex );
  virtual void ClearAllVertices();
  
  inline void SetNormal( const G4ThreeVector& newNormal );
  inline const G4ThreeVector GetNormal() const;
  
  virtual G4bool Clip( const G4VoxelLimits& voxelLimit );

  virtual G4bool PartialClip( const G4VoxelLimits& voxelLimit,
                              const EAxis IgnoreMe );
    // Clip, while ignoring the indicated axis.

  virtual void ClipAlongOneAxis( const G4VoxelLimits& voxelLimit,
                                 const EAxis axis );
    // Clip along just one axis, as specified in voxelLimit.

  virtual G4bool GetExtent( const EAxis axis, 
                                  G4double& min, G4double& max ) const;

  virtual const G4ThreeVector* GetMinPoint( const EAxis axis ) const;
    // Returns pointer to minimum point along the specified axis.
    // Take care! Do not use pointer after destroying parent polygon.

  virtual const G4ThreeVector* GetMaxPoint( const EAxis axis ) const;
    // Returns pointer to maximum point along the specified axis.
    // Take care! Do not use pointer after destroying parent polygon.

  inline G4int GetNumVertices() const;
  inline G4bool Empty() const;
  
  virtual G4bool InFrontOf( const G4ClippablePolygon& other, EAxis axis ) const;
    // Decide if the polygon is in "front" of another when
    // viewed along the specified axis. For our purposes here,
    // it is sufficient to use the minimum extent of the
    // polygon along the axis to determine this.

  virtual G4bool BehindOf( const G4ClippablePolygon& other, EAxis axis ) const;
    // Decide if this polygon is behind another.
    // Remarks in method "InFrontOf" are valid here too.

  virtual G4bool GetPlanerExtent( const G4ThreeVector& pointOnPlane, 
                                  const G4ThreeVector& planeNormal,
                                        G4double& min, G4double& max ) const;
    // Get min/max distance in or out of a plane.

  protected:  // with description

  void ClipToSimpleLimits( G4ThreeVectorList& pPolygon,
                           G4ThreeVectorList& outputPolygon,
                     const G4VoxelLimits& pVoxelLimit  );
    // pVoxelLimits must be only limited along one axis, and either
    // the maximum along the axis must be +kInfinity, or the minimum
    // -kInfinity

  protected:

  G4ThreeVectorList vertices;
  G4ThreeVector normal;
  G4double kCarTolerance;
};

#include "G4ClippablePolygon.icc"

#endif