store origin navState instead of G4TouchableHandle in HostTrackData

include/AdePT/integration/AdePTTrackingManager.hh

@@ -57,8 +57,11 @@ private:
   /// @brief Get the corresponding VecGeom NavigationState from the track's G4NavigationHistory, and set the boundary
   /// status based on the track's state
   /// @param aG4Track The G4Track from which to extract the NavigationState
+  /// @param aG4NavigationHistory Navigation history that is used to define the navState. If not provided, it will
+  /// default to aG4Track.GetNextTouchableHandle()->GetHistory()
   /// @return The corresponding vecgeom::NavigationState
-  const vecgeom::NavigationState GetVecGeomFromG4State(const G4Track &aG4Track);
+  const vecgeom::NavigationState GetVecGeomFromG4State(const G4Track &aG4Track,
+                                                       const G4NavigationHistory *aG4NavigationHistory = nullptr);
 
   std::unique_ptr<G4HepEmTrackingManagerSpecialized> fHepEmTrackingManager;
   static inline int fNumThreads{0};

include/AdePT/integration/HostTrackDataMapper.hh

@@ -6,7 +6,8 @@
 
 #include "G4VUserTrackInformation.hh"
 #include "G4VProcess.hh"
-#include "G4TouchableHandle.hh"
+
+#include <VecGeom/navigation/NavigationState.h>
 
 #include <unordered_map>
 #include <cstdint>
@@ -28,7 +29,7 @@ struct HostTrackData {
   G4LogicalVolume *logicalVolumeAtVertex = nullptr;
   G4ThreeVector vertexPosition;
   G4ThreeVector vertexMomentumDirection;
-  std::unique_ptr<G4TouchableHandle> originTouchableHandle;
+  vecgeom::NavigationState originNavState;
   G4double vertexKineticEnergy = 0.0;
   unsigned char particleType;
 

src/AdePTGeant4Integration.cpp

@@ -662,10 +662,7 @@ void AdePTGeant4Integration::FillG4Step(GPUHit const *aGPUHit, G4Step *aG4Step,
           G4ThreeVector{aGPUHit->fPostStepPoint.fMomentumDirection.x(), aGPUHit->fPostStepPoint.fMomentumDirection.y(),
                         aGPUHit->fPostStepPoint.fMomentumDirection.z()};
       hostTData.vertexKineticEnergy = aGPUHit->fPostStepPoint.fEKin;
-      if (hostTData.originTouchableHandle) {
-        hostTData.originTouchableHandle =
-            std::make_unique<G4TouchableHandle>(MakeTouchableFromNavState(aGPUHit->fPostStepPoint.fNavigationState));
-      }
+      hostTData.originNavState      = aGPUHit->fPostStepPoint.fNavigationState;
 
       // For the initializing step, the step defining process ID is the creator process
       const int stepId = aGPUHit->fStepLimProcessId;
@@ -906,8 +903,9 @@ void AdePTGeant4Integration::ReturnTrack(adeptint::TrackData const &track, unsig
   leakedTrack->SetVertexMomentumDirection(hostTData.vertexMomentumDirection);
   leakedTrack->SetVertexKineticEnergy(hostTData.vertexKineticEnergy);
   leakedTrack->SetLogicalVolumeAtVertex(hostTData.logicalVolumeAtVertex);
-  if (hostTData.originTouchableHandle) {
-    leakedTrack->SetOriginTouchableHandle(*hostTData.originTouchableHandle);
+  if (callUserActions) {
+    auto originTouchableHandle = MakeTouchableFromNavState(hostTData.originNavState);
+    leakedTrack->SetOriginTouchableHandle(originTouchableHandle);
   }
 
   // ------ Handle leaked tracks according to their status, if not LeakStatus::OutOfGPURegion ---------

src/AdePTTrackingManager.cc

@@ -397,23 +397,21 @@ void AdePTTrackingManager::ProcessTrack(G4Track *aTrack)
       // Get VecGeom Navigation state from G4History
       vecgeom::NavigationState converted = GetVecGeomFromG4State(*aTrack);
 
-      // Setting of the touchable should only be done when the userActions are called,
-      // as this otherwise leaves the touchable data for tracks that die on the GPU intact,
-      // causing a destructor fiasco when G4 is already shut down
+      // The VecGeom NavState is stored in the hostTrackData; in principle, the G4TouchableHandle could also be stored
+      // directly, but it has proven to be very expensive to create new G4TouchableHandle objects for each track in the
+      // HostTrackData. Instead, it was much cheaper to just store the vecgeom::NavState and create the
+      // G4TouchableHandle only when the track is returned from the GPU
       if (callUserActions) {
         if (aTrack->GetParentID() == 0 && aTrack->GetCurrentStepNumber() == 0) {
           // For the first step of primary tracks, the origin touchable handle is not set,
           // so we need to use the track's current position
           // If the vertex is not in a GPU region, the origin touchable handle will be set by the HepEmTrackingManager
-          if (aTrack->GetTouchable()) {
-            hostTrackData.originTouchableHandle = std::make_unique<G4TouchableHandle>(aTrack->GetTouchableHandle());
-          }
+          hostTrackData.originNavState = converted;
         } else {
           // For secondary tracks, the origin touchable handle is set when they are stacked
-          if (aTrack->GetOriginTouchable()) {
-            hostTrackData.originTouchableHandle =
-                std::make_unique<G4TouchableHandle>(aTrack->GetOriginTouchableHandle());
-          }
+          vecgeom::NavigationState convertedOrigin =
+              GetVecGeomFromG4State(*aTrack, aTrack->GetOriginTouchableHandle()->GetHistory());
+          hostTrackData.originNavState = convertedOrigin;
         }
       }
 
@@ -494,9 +492,15 @@ const vecgeom::NavigationState AdePTTrackingManager::GetVecGeomFromG4State(
   return aNavState;
 }
 
-const vecgeom::NavigationState AdePTTrackingManager::GetVecGeomFromG4State(const G4Track &aG4Track)
+const vecgeom::NavigationState AdePTTrackingManager::GetVecGeomFromG4State(
+    const G4Track &aG4Track, const G4NavigationHistory *aG4NavigationHistory)
 {
-  auto aNavState = GetVecGeomFromG4State(*aG4Track.GetNextTouchableHandle()->GetHistory());
+
+  if (!aG4NavigationHistory) {
+    aG4NavigationHistory = aG4Track.GetNextTouchableHandle()->GetHistory();
+  }
+
+  auto aNavState = GetVecGeomFromG4State(*aG4NavigationHistory);
 
   // Set boundary status based on the track
   if (aG4Track.GetStep() != nullptr) { // at initialization, the G4Step is not set yet, then we put OnBoundary to false