add functionality to set particle gun position, e.g. /mygun/position

FullSimLight/include/MyPrimaryGeneratorAction.hh

@@ -26,6 +26,7 @@ public:
   void SetPrimaryEnergy(G4double ekin);
   void SetPrimaryName(const G4String& pname);
   void SetPrimaryDirection(const G4ThreeVector &pdir);
+  void SetPrimaryPosition(const G4ThreeVector &ppos);
 
   static void   Print();
   static G4int  GetNumberOfPrimaryTypes()  {  return gNumberCandidateParticles; }
@@ -49,11 +50,13 @@ private:
   static G4double          gPrimaryEnergy;
   static std::string       gPrimaryType;
   static G4ThreeVector     gPrimaryDir;
+  static G4ThreeVector     gPrimaryPos;
 
 
   G4bool                   fIsUserNumPrimaryPerEvt;
   G4bool                   fIsUserPrimaryType;
   G4bool                   fIsUserPrimaryDir;
+  G4bool                   fIsUserPrimaryPos;
   G4bool                   fIsUserPrimaryEnergy;
 
   G4int                    fNumPrimaryPerEvt;

FullSimLight/include/MyPrimaryGeneratorMessenger.hh

@@ -27,6 +27,7 @@ private:
  G4UIcmdWithAString*        fPrimaryTypeCmd;
  G4UIcmdWithADoubleAndUnit* fPrimaryEnergyCmd;
  G4UIcmdWith3Vector*        fPrimaryDirCmd;
+ G4UIcmdWith3Vector*        fPrimaryPosCmd;
 
 };
 

FullSimLight/src/MyPrimaryGeneratorAction.cc

@@ -25,6 +25,7 @@ G4int            MyPrimaryGeneratorAction::gNumPrimaryPerEvt(-1);
 G4double         MyPrimaryGeneratorAction::gPrimaryEnergy(-1.);
 std::string      MyPrimaryGeneratorAction::gPrimaryType("");
 G4ThreeVector    MyPrimaryGeneratorAction::gPrimaryDir(0.,0.,0.);
+G4ThreeVector    MyPrimaryGeneratorAction::gPrimaryPos(0.,0.,0.);
 
 
 // These are the particle types that can be used as primary beam particle, on a event-by-event based.
@@ -88,6 +89,7 @@ void MyPrimaryGeneratorAction::GeneratePrimaries(G4Event* anEvent) {
       fPrimaryParticleDirection = G4RandomDirection();
     }
     // Beam position: always the origin i.e. [0,0,0].
+    // unless specified by user via SetPrimaryPosition
     //
     // Set the particle gun
     G4ParticleDefinition* pDef = fParticleTable->FindParticle(fPrimaryParticleName);
@@ -134,6 +136,12 @@ void  MyPrimaryGeneratorAction::SetPrimaryDirection(const G4ThreeVector &pdir) {
   fIsUserPrimaryDir         = true;
 }
 
+void  MyPrimaryGeneratorAction::SetPrimaryPosition(const G4ThreeVector &ppos) {
+  fPrimaryParticlePosition = ppos;
+  gPrimaryPos = fPrimaryParticlePosition;
+  fIsUserPrimaryPos         = true;
+}
+
 G4int MyPrimaryGeneratorAction::GetPrimaryTypeIndex(const G4String& pname) {
   G4int indx = gPrimaryNameToIndexMap.find(pname)->second;
   return indx;
@@ -161,6 +169,11 @@ void  MyPrimaryGeneratorAction::Print() {
   } else {
     str += "     Primary energy        : " + std::to_string(gPrimaryEnergy/GeV) + " [GeV] \n";
   }
+  G4String spos= "[";
+  spos += std::to_string(gPrimaryPos.x()) + ", "
+        + std::to_string(gPrimaryPos.y()) + ", "
+        + std::to_string(gPrimaryPos.x()) + "]\n";
+    str += "     Primary position     : " + spos;
   if (gPrimaryDir.mag()==0.) {
     str += "     Primary direction     : isotropic for each primary \n";
   } else {

FullSimLight/src/MyPrimaryGeneratorMessenger.cc

@@ -31,6 +31,10 @@ MyPrimaryGeneratorMessenger::MyPrimaryGeneratorMessenger(MyPrimaryGeneratorActio
  fPrimaryDirCmd       = new G4UIcmdWith3Vector("/mygun/direction",this);
  fPrimaryDirCmd->SetGuidance("set primary particle direction");
  fPrimaryDirCmd->AvailableForStates(G4State_PreInit,G4State_Idle);
+
+ fPrimaryPosCmd       = new G4UIcmdWith3Vector("/mygun/position",this);
+ fPrimaryPosCmd->SetGuidance("set primary particle position");
+ fPrimaryPosCmd->AvailableForStates(G4State_PreInit,G4State_Idle);
 }
 
 
@@ -40,6 +44,7 @@ MyPrimaryGeneratorMessenger::~MyPrimaryGeneratorMessenger() {
   delete fPrimaryTypeCmd;
   delete fPrimaryEnergyCmd;
   delete fPrimaryDirCmd;
+  delete fPrimaryPosCmd;
 }
 
 void MyPrimaryGeneratorMessenger::SetNewValue(G4UIcommand* command, G4String newValue) {
@@ -55,4 +60,7 @@ void MyPrimaryGeneratorMessenger::SetNewValue(G4UIcommand* command, G4String new
   if (command==fPrimaryDirCmd) {
     fTheGun->SetPrimaryDirection(fPrimaryDirCmd->GetNew3VectorValue(newValue));
   }
+  if (command==fPrimaryPosCmd) {
+    fTheGun->SetPrimaryPosition(fPrimaryPosCmd->GetNew3VectorValue(newValue));
+  }
 }