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// $Id: G4Track.cc,v 1.30 2007/10/02 00:46:21 kurasige Exp $
// GEANT4 tag $Name:  $
//
//
//---------------------------------------------------------------
//
//  G4Track.cc
//
//---------------------------------------------------------------
//   Add copy constructor            Hisaya Feb. 07 01
//   Fix GetVelocity                 Hisaya Feb. 17 01
//   Modification for G4TouchableHandle             22 Oct. 2001  R.Chytracek//
//   Fix GetVelocity (bug report #741)   Horton-Smith Apr 14 2005

#include "G4Track.hh"

G4Allocator<G4Track> aTrackAllocator;

///////////////////////////////////////////////////////////
G4Track::G4Track(G4DynamicParticle* apValueDynamicParticle,
                 G4double aValueTime,
                 const G4ThreeVector& aValuePosition)
///////////////////////////////////////////////////////////
  : fCurrentStepNumber(0),    fPosition(aValuePosition),
    fGlobalTime(aValueTime),  fLocalTime(0.),
    fTrackLength(0.),
    fParentID(0),             fTrackID(0),
    fpDynamicParticle(apValueDynamicParticle),
    fTrackStatus(fAlive),
    fBelowThreshold(false),   fGoodForTracking(false),
    fStepLength(0.0),         fWeight(1.0),
    fpStep(0),
    fVtxKineticEnergy(0.0),
    fpLVAtVertex(0),          fpCreatorProcess(0),
    fpUserInformation(0)
{    
}

//////////////////
G4Track::G4Track()
//////////////////
  : fCurrentStepNumber(0),    
    fGlobalTime(0),           fLocalTime(0.),
    fTrackLength(0.),
    fParentID(0),             fTrackID(0),
    fpDynamicParticle(0),
    fTrackStatus(fAlive),
    fBelowThreshold(false),   fGoodForTracking(false),
    fStepLength(0.0),         fWeight(1.0),
    fpStep(0),
    fVtxKineticEnergy(0.0),
    fpLVAtVertex(0),          fpCreatorProcess(0),
    fpUserInformation(0)
{
}
//////////////////
G4Track::G4Track(const G4Track& right)
//////////////////
{
  *this = right;
}

///////////////////
G4Track::~G4Track()
///////////////////
{
   delete fpDynamicParticle;
   delete fpUserInformation;
}

//////////////////
G4Track & G4Track::operator=(const G4Track &right)
//////////////////
{
  if (this != &right) {
   fPosition = right.fPosition;
   fGlobalTime = right.fGlobalTime;
   fLocalTime = right.fLocalTime;
   fTrackLength = right.fTrackLength;
   fWeight = right.fWeight;
   fStepLength = right.fStepLength;

   // Track ID (and Parent ID) is not copied and set to zero for new track
   fTrackID = 0;
   fParentID =0;

   // CurrentStepNumber is set to be 0
   fCurrentStepNumber = 0;

   // dynamic particle information 
   fpDynamicParticle = new G4DynamicParticle(*(right.fpDynamicParticle));
 
   // track status and flags for tracking  
   fTrackStatus = right.fTrackStatus;
   fBelowThreshold = right.fBelowThreshold;
   fGoodForTracking = right.fGoodForTracking;
   
   // Step information (Step Length, Step Number, pointer to the Step,) 
   // are not copied
   fpStep=0;

   // vertex information
   fVtxPosition = right.fVtxPosition;
   fpLVAtVertex = right.fpLVAtVertex;
   fVtxKineticEnergy = right.fVtxKineticEnergy;
   fVtxMomentumDirection = right.fVtxMomentumDirection;

   // CreatorProcess and UserInformation are not copied 
   fpCreatorProcess = 0;
   fpUserInformation = 0;
  }
  return *this;
}

///////////////////
void G4Track::CopyTrackInfo(const G4Track& right)
//////////////////
{
  *this = right;
}

#include "G4ParticleTable.hh"
///////////////////
G4double G4Track::GetVelocity() const
///////////////////
{ 
  static G4bool isFirstTime = true;
  static G4ParticleDefinition* fOpticalPhoton =0;
  
  static G4Material*               prev_mat =0;
  static G4MaterialPropertyVector* groupvel =0;
  static G4double                  prev_velocity =0;
  static G4double                  prev_momentum =0;
  

  if ( isFirstTime ) {
    isFirstTime = false;
    // set  fOpticalPhoton
    fOpticalPhoton = G4ParticleTable::GetParticleTable()->FindParticle("opticalphoton");
  }

  G4double velocity ;
  
  G4double mass = fpDynamicParticle->GetMass();

  // mass less particle  
  if( mass == 0. ){
    velocity = c_light ; 

    // special case for photons
    if ( (fOpticalPhoton !=0)  &&
	 (fpDynamicParticle->GetDefinition()==fOpticalPhoton) ){

       G4Material* mat=0; 
       G4bool update_groupvel = false;
       if ( this->GetStep() ){
	  mat= this->GetMaterial();         //   Fix for repeated volumes
       }else{
          if (fpTouchable!=0){ 
            mat=fpTouchable->GetVolume()->GetLogicalVolume()->GetMaterial();
          }
        }
       // check if previous step is in the same volume
       //  and get new GROUPVELOVITY table if necessary 
       if ((mat != prev_mat)||(groupvel==0)) {
	 groupvel = 0;
	 if(mat->GetMaterialPropertiesTable() != 0)
	   groupvel = mat->GetMaterialPropertiesTable()->GetProperty("GROUPVEL");
	 update_groupvel = true;
       }
       prev_mat = mat;
       
       if  (groupvel != 0 ) {
	 // light velocity = c/(rindex+d(rindex)/d(log(E_phot)))
	 // values stored in GROUPVEL material properties vector
	 velocity =  prev_velocity;
 	 
	 // check if momentum is same as in the previous step
         //  and calculate group velocity if necessary 
 	 if( update_groupvel || (fpDynamicParticle->GetTotalMomentum() != prev_momentum) ) {
	   velocity =
	     groupvel->GetProperty(fpDynamicParticle->GetTotalMomentum());
	   prev_velocity = velocity;
	   prev_momentum = fpDynamicParticle->GetTotalMomentum();
	 }
       }
     }

  } else {
    G4double T = fpDynamicParticle->GetKineticEnergy();
    velocity = c_light*std::sqrt(T*(T+2.*mass))/(T+mass);
  }
                                                                                
  return velocity ;
}