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// $Id: G4AffineTransform.hh,v 1.6 2006/06/29 18:30:37 gunter Exp $
// GEANT4 tag $Name: geant4-09-03 $
//
//
// class G4AffineTransform
//
// Class description:
//
// A class for geometric affine transformations [see, eg. Foley & Van Dam]
// Supports efficient arbitrary rotation & transformation of vectors and the
// computation of compound & inverse transformations. A `rotation flag' is
// maintained internally for greater computational efficiency for transforms
// that do not involve rotation.
//
// Interfaces to the CLHEP classes G4ThreeVector & G4RotationMatrix
//
// For member function descriptions, see comments by declarations. For
// additional clarification, also check the `const' declarations for
// functions & their parameters.
//
// Member data:
//
//      G4double rxx,rxy,rxz; 
//      G4double ryx,ryy,ryz;  A 3x3 rotation matrix - net rotation
//      G4double rzx,rzy,rzz;
//      G4double tx,ty,tz;     Net translation 

// History:
// Paul R C Kent 6 Aug 1996 - initial version
//
// 19.09.96 E.Chernyaev:
// - direct access to the protected members of the G4RotationMatrix class
//   replaced by access via public access functions            
// - conversion of the rotation matrix to angle & axis used to get
//   a possibility to remove "friend" from the G4RotationMatrix class
// --------------------------------------------------------------------
#ifndef G4AFFINETRANSFORM_HH
#define G4AFFINETRANSFORM_HH

#include "G4Types.hh"
#include "G4ThreeVector.hh"
#include "G4RotationMatrix.hh"

class G4AffineTransform
{

public:

  G4AffineTransform();

public: // with description

  G4AffineTransform(const G4ThreeVector &tlate);
    // Translation only: under t'form translate point at origin by tlate

  G4AffineTransform(const G4RotationMatrix &rot);
    // Rotation only: under t'form rotate by rot

  G4AffineTransform(const G4RotationMatrix &rot,
                    const G4ThreeVector &tlate);
    // Under t'form: rotate by rot then translate by tlate

  G4AffineTransform(const G4RotationMatrix *rot,
                    const G4ThreeVector &tlate);
    // Optionally rotate by *rot then translate by tlate - rot may be null
  
  G4AffineTransform operator * (const G4AffineTransform &tf) const;
    // Compound Transforms:
    //       tf2=tf2*tf1 equivalent to tf2*=tf1
    //       Returns compound transformation of self*tf

  G4AffineTransform& operator *= (const G4AffineTransform &tf);
    // (Modifying) Multiplies self by tf; Returns self reference
    //             ie. A=AB for a*=b


  G4AffineTransform& Product(const G4AffineTransform &tf1,
                             const G4AffineTransform &tf2);
    // 'Products' for avoiding (potential) temporaries:
    //            c.Product(a,b) equivalent to c=a*b
    //            c.InverseProduct(a*b,b ) equivalent to c=a
    // (Modifying) Sets self=tf1*tf2; Returns self reference

  G4AffineTransform& InverseProduct(const G4AffineTransform &tf1,
                                    const G4AffineTransform &tf2);
    // (Modifying) Sets self=tf1*(tf2^-1); Returns self reference

  G4ThreeVector TransformPoint(const G4ThreeVector &vec) const;
    // Transform the specified point: returns vec*rot+tlate

  G4ThreeVector TransformAxis(const G4ThreeVector &axis) const;
    // Transform the specified axis: returns

  void ApplyPointTransform(G4ThreeVector &vec) const;
    // Transform the specified point (in place): sets vec=vec*rot+tlate

  void ApplyAxisTransform(G4ThreeVector &axis) const;
    // Transform the specified axis (in place): sets axis=axis*rot;

  G4AffineTransform Inverse() const;
    // Return inverse of current transform

  G4AffineTransform& Invert();
    // (Modifying) Sets self=inverse of self; Returns self reference

  G4AffineTransform& operator +=(const G4ThreeVector &tlate);
  G4AffineTransform& operator -=(const G4ThreeVector &tlate);
    // (Modifying) Adjust net translation by given vector;
    //             Returns self reference

  G4bool operator == (const G4AffineTransform &tf) const;
  G4bool operator != (const G4AffineTransform &tf) const;

  G4double operator [] (const G4int n) const;

  G4bool IsRotated() const;
    // True if transform includes rotation

  G4bool IsTranslated() const;
    // True if transform includes translation

  G4RotationMatrix NetRotation() const;

  G4ThreeVector NetTranslation() const;

  void SetNetRotation(const G4RotationMatrix &rot);

  void SetNetTranslation(const G4ThreeVector &tlate);

private:

  G4AffineTransform(const G4double prxx,const G4double prxy,const G4double prxz,
                    const G4double pryx,const G4double pryy,const G4double pryz,
                    const G4double przx,const G4double przy,const G4double przz,
                    const G4double ptx, const G4double pty, const G4double ptz );

  G4double rxx,rxy,rxz;
  G4double ryx,ryy,ryz;
  G4double rzx,rzy,rzz;
  G4double tx,ty,tz;
};

#include "G4AffineTransform.icc"

#endif