Rough banking of surface source into surf_src_bank

include/openmc/particle.h

@@ -159,6 +159,8 @@ public:
     neutron, photon, electron, positron
   };
 
+  int64_t icross = 0;
+
   //! Saved ("banked") state of a particle
   //! NOTE: This structure's MPI type is built in initialize_mpi() of
   //! initialize.cpp. Any changes made to the struct here must also be

src/particle.cpp

@@ -423,6 +423,8 @@ Particle::cross_surface()
     site.particle = this->type_;
     // site.parent_id = this->id_;
     // site.progeny_id = this->n_progeny_;
+    simulation::surf_src_bank[Particle::icross] = site;
+    Particle::icross += 1;
   }
 
   // Handle any applicable boundary conditions.