AuxDetReadoutGeometry.cxx

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#include "nug4/G4Base/DetectorConstruction.h"

// Framework includes
#include "messagefacility/MessageLogger/MessageLogger.h"

// LArSoft includes
#include "larcorealg/Geometry/AuxDetGeometryCore.h"
#include "larsim/LegacyLArG4/AuxDetReadout.h"
#include "larsim/LegacyLArG4/AuxDetReadoutGeometry.h"

// G4 includes
#include "Geant4/G4LogicalVolume.hh"
#include "Geant4/G4Point3D.hh"
#include "Geant4/G4SDManager.hh"

namespace larg4 {

  // Constructor and destructor.
  AuxDetReadoutGeometry::AuxDetReadoutGeometry(geo::AuxDetGeometryCore const* auxDetGeom,
                                               G4String const name)
    : G4VUserParallelWorld(name), fAuxDetGeom{auxDetGeom}, fNumSensitiveVol(0)
  {}

  void AuxDetReadoutGeometry::Construct()
  {
    // We want to find all of the AuxDets that the Geometry service would find and make
    // each one a G4 sensitive detector.

    // Call initial case of a function that will rucursively run through the volume tree
    // down to max depth. Start at 0 depth with World, where the initial translation and
    // rotation should be 0 as well
    unsigned int MaxDepth = 8; // should be plenty
    std::vector<const G4VPhysicalVolume*> path(MaxDepth);
    path[0] = g4b::DetectorConstruction::GetWorld();
    G4Transform3D InitTransform(path[0]->GetObjectRotationValue(), path[0]->GetObjectTranslation());

    // first try to make sensitive volumes, if those are not in the gdml file (ie file was
    // made before the introduction of sensitive volumes) fall back to looking for the aux
    // dets
    FindAndMakeAuxDetSensitive(path, 0, InitTransform);
    if (fNumSensitiveVol < 1) FindAndMakeAuxDet(path, 0, InitTransform);
  }

  //---------------------------------------------------------------
  void AuxDetReadoutGeometry::FindAndMakeAuxDetSensitive(
    std::vector<const G4VPhysicalVolume*>& path,
    unsigned int depth,
    G4Transform3D DepthToWorld)
  {
    G4LogicalVolume* LogicalVolumeAtDepth = path[depth]->GetLogicalVolume();

    std::string volName(path[depth]->GetName());
    if (volName.find("volAuxDet") != std::string::npos &&
        volName.find("Sensitive") != std::string::npos) {

      // find world coordinate of the AuxDet origin in cm
      G4Point3D local(0., 0., 0.);
      G4Point3D world = DepthToWorld * local; // G4 works in mm
      geo::Point_t const worldPos{
        world.x() / CLHEP::cm, world.y() / CLHEP::cm, world.z() / CLHEP::cm};

      size_t adNum = 0;
      size_t svNum = 0;
      fAuxDetGeom->FindAuxDetSensitiveAtPosition(worldPos, adNum, svNum);
      //  N.B. This name is expected by code in LArG4:
      std::string SDName = "AuxDetSD_AuxDet" + std::to_string(adNum) + "_" + std::to_string(svNum);
      AuxDetReadout* adReadout = new larg4::AuxDetReadout(SDName, adNum, svNum);

      MF_LOG_DEBUG("AuxDetReadoutGeometry")
        << "found" << path[depth]->GetName() << ", number " << adNum << ":" << svNum;

      // Tell Geant4's sensitive-detector manager about the AuxDetReadout class
      (G4SDManager::GetSDMpointer())->AddNewDetector(adReadout);
      LogicalVolumeAtDepth->SetSensitiveDetector(adReadout);
      ++fNumSensitiveVol;
      return;
    }

    // Explore the next layer down -- unless it is a very deep geometry,
    // recursion should end before exception is thrown.
    unsigned int deeper = depth + 1;
    if (deeper >= path.size()) {
      throw cet::exception("AuxDetReadoutGeometry") << "exceeded maximum TGeoNode depth\n";
    }

    // Note that there will be nd different branches off of path[depth]
    G4int nd = LogicalVolumeAtDepth->GetNoDaughters();
    for (int d = 0; d < nd; ++d) {

      // get the physvol daughter in the logicalvol
      path[deeper] = LogicalVolumeAtDepth->GetDaughter(d);

      // keep track of the transform to world coordinates for PositionToAuxDet
      G4Transform3D DeeperToMother(path[deeper]->GetObjectRotationValue(),
                                   path[deeper]->GetObjectTranslation());
      G4Transform3D DeeperToWorld = DepthToWorld * DeeperToMother;
      FindAndMakeAuxDetSensitive(path, deeper, DeeperToWorld);
    }
  }

  //---------------------------------------------------------------
  void AuxDetReadoutGeometry::FindAndMakeAuxDet(std::vector<const G4VPhysicalVolume*>& path,
                                                unsigned int depth,
                                                G4Transform3D DepthToWorld)
  {
    G4LogicalVolume* LogicalVolumeAtDepth = path[depth]->GetLogicalVolume();

    std::string volName(path[depth]->GetName());
    if (volName.find("volAuxDet") != std::string::npos) {

      // find world coordinate of the AuxDet origin in cm
      G4Point3D local(0., 0., 0.);
      G4Point3D world = DepthToWorld * local; // G4 works in mm
      geo::Point_t const worldPos{
        world.x() / CLHEP::cm, world.y() / CLHEP::cm, world.z() / CLHEP::cm};

      auto const adNum = fAuxDetGeom->FindAuxDetAtPosition(worldPos);
      //  N.B. This name is expected by code in LArG4:
      std::string SDName = "AuxDetSD_AuxDet" + std::to_string(adNum) + "_0";
      AuxDetReadout* adReadout = new larg4::AuxDetReadout(SDName, adNum, 0);

      MF_LOG_DEBUG("AuxDetReadoutGeometry")
        << "found" << path[depth]->GetName() << ", number " << adNum << ":0";

      // Tell Geant4's sensitive-detector manager about the AuxDetReadout class
      (G4SDManager::GetSDMpointer())->AddNewDetector(adReadout);
      LogicalVolumeAtDepth->SetSensitiveDetector(adReadout);
      ++fNumSensitiveVol;
      return;
    }

    // Explore the next layer down -- unless it is a very deep geometry,
    // recursion should end before exception is thrown.
    unsigned int deeper = depth + 1;
    if (deeper >= path.size()) {
      throw cet::exception("AuxDetReadoutGeometry") << "exceeded maximum TGeoNode depth\n";
    }

    // Note that there will be nd different branches off of path[depth]
    G4int nd = LogicalVolumeAtDepth->GetNoDaughters();
    for (int d = 0; d < nd; ++d) {

      // get the physvol daughter in the logicalvol
      path[deeper] = LogicalVolumeAtDepth->GetDaughter(d);

      // keep track of the transform to world coordinates for PositionToAuxDet
      G4Transform3D DeeperToMother(path[deeper]->GetObjectRotationValue(),
                                   path[deeper]->GetObjectTranslation());
      G4Transform3D DeeperToWorld = DepthToWorld * DeeperToMother;
      FindAndMakeAuxDet(path, deeper, DeeperToWorld);
    }
  }

} // namespace larg4