Geant4SDActions.cpp

// $Id:$
//====================================================================
//  AIDA Detector description implementation for LCD
//--------------------------------------------------------------------
//
//  Author     : M.Frank
//
//====================================================================
// Framework include files
#include "DDG4/Geant4SensDetAction.inl"
#include "DDG4/Geant4EventAction.h"
#include "G4OpticalPhoton.hh"
#include "G4VProcess.hh"

/// Namespace for the AIDA detector description toolkit
namespace DD4hep {

  /// Namespace for the Geant4 based simulation part of the AIDA detector description toolkit
  namespace Simulation   {

    // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    //               Geant4SensitiveAction<Geant4Tracker>
    // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    /// Define collections created by this sensitivie action object
    template <> void Geant4SensitiveAction<Geant4Tracker>::defineCollections() {
      m_collectionID = defineCollection<Geant4Tracker::Hit>(m_sensitive.readout().name());
    }

    /// Method for generating hit(s) using the information of G4Step object.
    template <> bool Geant4SensitiveAction<Geant4Tracker>::process(G4Step* step,G4TouchableHistory* /*hist*/ ) {
      typedef Geant4Tracker::Hit Hit;
      StepHandler h(step);
      Position prePos    = h.prePos();
      Position postPos   = h.postPos();
      Position direction = postPos - prePos;
      Position position  = mean_direction(prePos,postPos);
      double   hit_len   = direction.R();

      if ( step->GetTotalEnergyDeposit() < std::numeric_limits<double>::epsilon() )
        return true;
      else if (hit_len > 0) {
        double new_len = mean_length(h.preMom(),h.postMom())/hit_len;
        direction *= new_len/hit_len;
      }
      print("Geant4Tracker","%s> Add hit with deposit:%e MeV  Pos:%8.2f %8.2f %8.2f",
            c_name(),step->GetTotalEnergyDeposit(),position.X(),position.Y(),position.Z());
      Hit* hit = new Hit(h.trkID(), h.trkPdgID(), h.deposit(), h.track->GetGlobalTime());
      if ( hit )  {
        HitContribution contrib = Hit::extractContribution(step);
        hit->cellID        = cellID(step);
        hit->energyDeposit = contrib.deposit;
        hit->position      = position;
        hit->momentum      = direction;
        hit->length        = hit_len;
        collection(m_collectionID)->add(hit);
        mark(h.track);
        if ( 0 == hit->cellID )  {
          hit->cellID        = volumeID( step ) ;
          except("+++ Invalid CELL ID for hit!");
        }
        print("Geant4Tracker","%s> Hit with deposit:%f  Pos:%f %f %f ID=%016X",
              c_name(),step->GetTotalEnergyDeposit(),position.X(),position.Y(),position.Z(),
              (void*)hit->cellID);
        Geant4TouchableHandler handler(step);
        print("Geant4Tracker","%s>     Geant4 path:%s",c_name(),handler.path().c_str());
        return true;
      }
      except("new() failed: Cannot allocate hit object");
      return false;
    }
    typedef Geant4SensitiveAction<Geant4Tracker> Geant4TrackerAction;

    // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    //               Geant4SensitiveAction<Calorimeter>
    // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    /// Define collections created by this sensitivie action object
    template <> void Geant4SensitiveAction<Geant4Calorimeter>::defineCollections() {
      m_collectionID = defineCollection<Geant4Calorimeter::Hit>(m_sensitive.readout().name());
    }
    /// Method for generating hit(s) using the information of G4Step object.
    template <> bool Geant4SensitiveAction<Geant4Calorimeter>::process(G4Step* step,G4TouchableHistory*) {
      typedef Geant4Calorimeter::Hit Hit;
      StepHandler h(step);
      HitContribution contrib = Hit::extractContribution(step);
      HitCollection*  coll    = collection(m_collectionID);
      long long int   cell    = cellID(step);

      Hit* hit = coll->find<Hit>(CellIDCompare<Hit>(cell));
      if ( h.totalEnergy() < std::numeric_limits<double>::epsilon() )  {
        return true;
      }
      else if ( !hit ) {
        Geant4TouchableHandler handler(step);
        DDSegmentation::Vector3D pos = m_segmentation.position(cell);
        Position global = h.localToGlobal(pos);
        hit = new Hit(global);
        hit->cellID = cell;
        coll->add(hit);
        printM2("Geant4Calorimeter","%s> CREATE hit with deposit:%e MeV  Pos:%8.2f %8.2f %8.2f  %s",
                c_name(),contrib.deposit,pos.X,pos.Y,pos.Z,handler.path().c_str());
        if ( 0 == hit->cellID )  { // for debugging only!
          hit->cellID = cellID(step);
          except("+++ Invalid CELL ID for hit!");
        }
      }
      hit->truth.push_back(contrib);
      hit->energyDeposit += contrib.deposit;
      mark(step);
      return true;
    }
    typedef Geant4SensitiveAction<Geant4Calorimeter> Geant4CalorimeterAction;

    // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    //               Geant4SensitiveAction<OpticalCalorimeter>
    // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    /// Helper class to define properties of optical calorimeters. UNTESTED
    /**
     *  \author  M.Frank
     *  \version 1.0
     *  \ingroup DD4HEP_SIMULATION
     */
    struct Geant4OpticalCalorimeter {};

    /// Define collections created by this sensitivie action object
    template <> void Geant4SensitiveAction<Geant4OpticalCalorimeter>::defineCollections() {
      m_collectionID = defineCollection<Geant4Calorimeter::Hit>(m_sensitive.readout().name());
    }
    /// Method for generating hit(s) using the information of G4Step object.
    template <> bool Geant4SensitiveAction<Geant4OpticalCalorimeter>::process(G4Step* step,G4TouchableHistory*) {
      G4Track * track =  step->GetTrack();
      // check that particle is optical photon:
      if( track->GetDefinition() != G4OpticalPhoton::OpticalPhotonDefinition() )  {
        return false;
      }
      else if ( track->GetCreatorProcess()->G4VProcess::GetProcessName() != "Cerenkov")  {
        track->SetTrackStatus(fStopAndKill);
        return false;
      }
      else {
        typedef Geant4Calorimeter::Hit Hit;
        StepHandler h(step);
        HitCollection*  coll    = collection(m_collectionID);
        HitContribution contrib = Hit::extractContribution(step);
        Position        pos     = h.prePos();
        Hit* hit = coll->find<Hit>(PositionCompare<Hit,Position>(pos));
        if ( !hit ) {
          hit = new Hit(pos);
          hit->cellID = volumeID(step);
          coll->add(hit);
          if ( 0 == hit->cellID )  {
            hit->cellID = volumeID(step);
            except("+++ Invalid CELL ID for hit!");
          }
        }
        hit->energyDeposit += contrib.deposit;
        hit->truth.push_back(contrib);
        track->SetTrackStatus(fStopAndKill); // don't step photon any further
        mark(h.track);
        return true;
      }
    }
    typedef Geant4SensitiveAction<Geant4OpticalCalorimeter>  Geant4OpticalCalorimeterAction;


    /// Geant4 sensitive detector combining all deposits of one G4Track within one sensitive element.
    /**
     *  Geant4SensitiveAction<TrackerCombine>
     *
     *
     *  \author  M.Frank
     *  \version 1.0
     *  \ingroup DD4HEP_SIMULATION
     */
    struct TrackerCombine {
      typedef Geant4HitCollection HitCollection;
      Geant4Tracker::Hit  pre, post;
      Position          mean_pos;
      Geant4Sensitive*  sensitive;
      double            mean_time;
      double            e_cut;
      int               current;
      int               combined;
      long long int     cell;

      TrackerCombine() : pre(), post(), sensitive(0), e_cut(0.0), current(-1), combined(0), cell(0)  {
      }

      /// Start a new hit
      void start(G4Step* step, G4StepPoint* point)   {
        pre.storePoint(step,point);
        pre.truth.deposit = 0.0;
        current = pre.truth.trackID;
        sensitive->mark(step->GetTrack());
        mean_pos.SetXYZ(0,0,0);
        mean_time = 0;
        post = pre;
        combined = 0;
        cell = 0;
      }

      /// Update energy and track information during hit info accumulation
      void update(G4Step* step) {
        post.storePoint(step,step->GetPostStepPoint());
        pre.truth.deposit += post.truth.deposit;
        mean_pos.SetX(mean_pos.x()+post.position.x()*post.truth.deposit);
        mean_pos.SetY(mean_pos.y()+post.position.y()*post.truth.deposit);
        mean_pos.SetZ(mean_pos.z()+post.position.z()*post.truth.deposit);
        mean_time += post.truth.time*post.truth.deposit;
        if ( 0 == cell )   {
          cell = sensitive->cellID(step);
          if ( 0 == cell )  {
            cell = sensitive->volumeID(step) ;
            sensitive->except("+++ Invalid CELL ID for hit!");
          }
        }
        ++combined;
      }

      /// Clear collected information and restart for new hit
      void clear()  {
        mean_pos.SetXYZ(0,0,0);
        mean_time = 0;
        post.clear();
        pre.clear();
        current = -1;
        combined = 0;
        cell = 0;
      }

      /// Helper function to decide if the hit has to be extracted and saved in the collection
      bool mustSaveTrack(const G4Track* tr)  const   {
        return current > 0 && current != tr->GetTrackID();
      }

      /// Extract hit information and add the created hit to the collection
      void extractHit(Geant4HitCollection* collection)   {
        if ( current == -1 ) {
          return;
        }
        double deposit = pre.truth.deposit, time = mean_time / deposit;
        Position pos = mean_pos / deposit;
        Momentum mom = 0.5 * (pre.momentum + post.momentum);
        double path_len = (post.position - pre.position).R();
        Geant4Tracker::Hit* hit = new Geant4Tracker::Hit(pre.truth.trackID,
                                                         pre.truth.pdgID,
                                                         deposit,time);
        hit->position = pos;
        hit->momentum = mom;
        hit->length   = path_len;
        hit->cellID   = cell;
        collection->add(hit);
        sensitive->printM2("+++ TrackID:%6d [%s] CREATE hit combination with %2d deposit(s):"
                           " %e MeV  Pos:%8.2f %8.2f %8.2f",
                           pre.truth.trackID,sensitive->c_name(),combined,pre.truth.deposit/MeV,
                           pos.X()/mm,pos.Y()/mm,pos.Z()/mm);
        clear();
      }


      /// Method for generating hit(s) using the information of G4Step object.
      G4bool process(G4Step* step, G4TouchableHistory* ) {
        Geant4StepHandler h(step);
        void *prePV = h.volume(h.pre), *postPV = h.volume(h.post);

        Geant4HitCollection* coll = sensitive->collection(0);
        /// If we are handling a new track, then store the content of the previous one.
        if ( mustSaveTrack(h.track) )  {
          extractHit(coll);
        }
        /// There must be something in.
        if ( h.deposit()/keV <= 0 )  {
          return false;
        }
        /// Initialize the deposits of the next hit.
        if ( current < 0 )  {
          start(step, h.pre);
        }
        /// ....update .....
        update(step);

        if ( prePV != postPV ) {
          void* postSD = h.sd(h.post);
          extractHit(coll);
          if ( 0 != postSD )   {
            void* preSD = h.sd(h.pre);
            if ( preSD == postSD ) {
              start(step,h.post);
            }
          }
        }
        else if ( h.track->GetTrackStatus() == fStopAndKill ) {
          extractHit(coll);
        }
        return true;
      }

      /// Post-event action callback
      void endEvent(const G4Event* /* event */)   {
        // We need to add the possibly last added hit to the collection here.
        // otherwise the last hit would be assigned to the next event and the
        // MC truth would be screwed.
        //
        // Alternatively the 'update' method would become rather CPU consuming,
        // beacuse the extract action would have to be recalculated over and over.
        if ( current > 0 )   {
          Geant4HitCollection* coll = sensitive->collection(0);
          extractHit(coll);
        }
      }
    };

    /// Initialization overload for specialization
    template <> void Geant4SensitiveAction<TrackerCombine>::initialize() {
      eventAction().callAtEnd(&m_userData,&TrackerCombine::endEvent);
      m_userData.e_cut = m_sensitive.energyCutoff();
      m_userData.sensitive = this;
    }

    /// Define collections created by this sensitivie action object
    template <> void Geant4SensitiveAction<TrackerCombine>::defineCollections() {
      m_collectionID = defineCollection<Geant4Tracker::Hit>(m_sensitive.readout().name());
    }

    /// Method for generating hit(s) using the information of G4Step object.
    template <> void Geant4SensitiveAction<TrackerCombine>::clear(G4HCofThisEvent*) {
      m_userData.clear();
    }

    /// Method for generating hit(s) using the information of G4Step object.
    template <> G4bool
    Geant4SensitiveAction<TrackerCombine>::process(G4Step* step, G4TouchableHistory* history) {
      return m_userData.process(step, history);
    }

    typedef Geant4SensitiveAction<TrackerCombine>  Geant4TrackerCombineAction;

    typedef Geant4TrackerAction Geant4SimpleTrackerAction;
    typedef Geant4CalorimeterAction Geant4SimpleCalorimeterAction;
    typedef Geant4OpticalCalorimeterAction Geant4SimpleOpticalCalorimeterAction;
  }
}

using namespace DD4hep::Simulation;

#include "DDG4/Factories.h"
DECLARE_GEANT4SENSITIVE(Geant4TrackerAction)
DECLARE_GEANT4SENSITIVE(Geant4TrackerCombineAction)
DECLARE_GEANT4SENSITIVE(Geant4CalorimeterAction)
DECLARE_GEANT4SENSITIVE(Geant4OpticalCalorimeterAction)

// Need these factories for backwards compatibility
DECLARE_GEANT4SENSITIVE(Geant4SimpleTrackerAction)
DECLARE_GEANT4SENSITIVE(Geant4SimpleCalorimeterAction)
DECLARE_GEANT4SENSITIVE(Geant4SimpleOpticalCalorimeterAction)