ISFG4Helper.cxx

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/*
  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
*/
 
// class header
#include "ISF_Geant4Event/ISFG4Helper.h"
 
// Geant4 includes
#include "G4Track.hh"
#include "G4ThreeVector.hh"
 
#include "AtlasHepMC/GenParticle.h"
#include "TruthUtils/MagicNumbers.h"
 
// G4Atlas includes
#include "MCTruth/TrackInformation.h"
 
// ISF includes
#include "ISF_Event/ISFParticle.h"
 
 
// ATLAS GeoPrimitves (Amg::Vector3D etc)
#include "GeoPrimitives/GeoPrimitives.h"
 

ISF::ISFParticle*
iGeant4::ISFG4Helper::convertG4TrackToISFParticle(const G4Track& aTrack,
                                                   const ISF::ISFParticle& parent,
                                                   ISF::TruthBinding* truth)
{
  const G4ThreeVector& g4pos = aTrack.GetPosition();
  const double         gTime = aTrack.GetGlobalTime();
  const Amg::Vector3D  position(g4pos.x(),g4pos.y(),g4pos.z());
 
  const G4ThreeVector& g4mom = aTrack.GetMomentum();
  const Amg::Vector3D  momentum(g4mom.x(),g4mom.y(),g4mom.z());
 
  const G4ParticleDefinition &particleDefinition = *aTrack.GetDefinition();
  double mass    = particleDefinition.GetPDGMass();
  double charge  = particleDefinition.GetPDGCharge();
  int    pdgID   = particleDefinition.GetPDGEncoding();
 
  int barcode = (truth && truth->getCurrentGenParticle() ) ?  HepMC::barcode(truth->getCurrentGenParticle()) : HepMC::UNDEFINED_ID; // FIXME barcode-based
  const int id = (truth && truth->getCurrentGenParticle() ) ? HepMC::uniqueID(truth->getCurrentGenParticle()) : HepMC::UNDEFINED_ID;
  const int status = (truth && truth->getCurrentGenParticle() ) ? truth->getCurrentGenParticle()->status() : 1;
  ISF::ISFParticle *isp = new ISF::ISFParticle( position,
                                                momentum,
                                                mass,
                                                charge,
                                                pdgID,
                                                status,
                                                gTime,
                                                parent,
                                                id,
                                                barcode, // FIXME barcode-based
                                                truth
                                               );
 
  return isp;
}
 

VTrackInformation *
iGeant4::ISFG4Helper::getISFTrackInfo(const G4Track& aTrack)
{
  VTrackInformation* trackInfo = static_cast<VTrackInformation*>(aTrack.GetUserInformation());
  return trackInfo;
}
 

TrackInformation*
iGeant4::ISFG4Helper::attachTrackInfoToNewG4Track( G4Track& aTrack,
                                                    ISF::ISFParticle& baseIsp,
                                                    VTrackInformation::TrackClassification classification,
                                                    HepMC::GenParticlePtr generationZeroGenParticle)
{
  if ( aTrack.GetUserInformation() ) {
    G4ExceptionDescription description;
    description << G4String("ISFG4Helper::attachTrackInfoToNewG4Track: ")
                << "Trying to attach new TrackInformation object to G4Track which already has a TrackUserInformation attached (trackID: "
                << aTrack.GetTrackID() << ", track pos: "<<aTrack.GetPosition() << ", mom: "<<aTrack.GetMomentum()
                << ", parentID " << aTrack.GetParentID() << ")";
    G4Exception("ISFG4Helper::attachTrackInfoToNewG4Track", "TrackUserInformationAlreadyExists", FatalException, description);
    return nullptr;
  }
 
  auto* truthBinding = baseIsp.getTruthBinding();
  if ( !truthBinding ) {
    G4ExceptionDescription description;
    description << G4String("ISFG4Helper::attachTrackInfoToNewG4Track: ")
                << "No TruthBinding present in base ISFParticle (trackID: "
                << aTrack.GetTrackID() << ", track pos: "<<aTrack.GetPosition() << ", mom: "<<aTrack.GetMomentum()
                << ", parentID " << aTrack.GetParentID() << ", ISFParticle: "<<baseIsp<<")";
    G4Exception("ISFG4Helper::attachTrackInfoToNewG4Track", "NoISFTruthBinding", FatalException, description);
    return nullptr;
  }
 
  TrackInformation *trackInfo = new TrackInformation( nullptr, &baseIsp );
  trackInfo->SetPrimaryGenParticle( truthBinding->getPrimaryGenParticle() );
  trackInfo->SetGenerationZeroGenParticle( generationZeroGenParticle );
  if (classification != VTrackInformation::Secondary) {
    trackInfo->SetCurrentGenParticle( truthBinding->getCurrentGenParticle() );
  }
  trackInfo->SetClassification( classification );
  aTrack.SetUserInformation( trackInfo );
 
  return trackInfo;
}