add field reading on stepping action. commented out at the moment.

FullSimLight/src/MySteppingAction.cc

@@ -5,6 +5,8 @@
 #include "MyTrackInformation.hh"
 #include "G4Step.hh"
 #include "G4ParticleDefinition.hh"
+#include "G4FieldManager.hh"
+#include "G4Field.hh"
 
 
 MySteppingAction::MySteppingAction(MyEventAction* evtact) : G4UserSteppingAction(), fEventAction(evtact) {}
@@ -20,4 +22,30 @@ void MySteppingAction::UserSteppingAction(const G4Step* theStep) {
   G4bool   isCharged = (theTrack->GetDefinition()->GetPDGCharge()!=0.);
   G4int primTrackID  = static_cast<MyTrackInformation*>(theTrack->GetUserInformation())->GetPrimaryTrackID();
   fEventAction->AddData(edep, stepl, isCharged, primTrackID-1);
-}
+
+  /* read and print field
+
+  const G4int stepNumber = theTrack->GetCurrentStepNumber();
+  std::cout<<"CurrentStepNumber is: "<<stepNumber<<std::endl;
+
+  auto preStepPoint = theStep->GetPreStepPoint();
+  auto position = preStepPoint->GetPosition();
+  const double point[3] = {position.getX(), position.getY(), position.getZ()};
+
+  auto volume = preStepPoint->GetPhysicalVolume()->GetLogicalVolume();
+  auto fieldManager = volume->GetFieldManager();
+  if (fieldManager) {
+  	const G4Field* field = fieldManager->GetDetectorField();
+  	if (field) {
+  		std::cout<<"Field DOES exist!"<<std::endl;
+  		double fieldValue[3];
+  		field->GetFieldValue(point, fieldValue);
+  		std::cout<<"Field value is: "<<fieldValue[0]<<", "<<fieldValue[1]<<", "<<fieldValue[2]<<std::endl;
+  	}
+  	else 
+  		std::cout<<"Field does NOT exist!"<<std::endl;
+  }
+  else 
+  	std::cout<<"Field manager does NOT exist!"<<std::endl;
+  */
+}
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