Make vehicle::handle_trap use references

src/grab.cpp

@@ -202,8 +202,9 @@ bool game::grabbed_veh_move( const tripoint &dp )
 
     for( int p : wheel_indices ) {
         if( one_in( 2 ) ) {
-            tripoint wheel_p = grabbed_vehicle->global_part_pos3( grabbed_part );
-            grabbed_vehicle->handle_trap( wheel_p, p );
+            vehicle_part &vp_wheel = grabbed_vehicle->part( p );
+            tripoint wheel_p = grabbed_vehicle->global_part_pos3( vp_wheel );
+            grabbed_vehicle->handle_trap( wheel_p, vp_wheel );
         }
     }
 

src/map.cpp

@@ -849,22 +849,24 @@ vehicle *map::move_vehicle( vehicle &veh, const tripoint &dp, const tileray &fac
         const float weight_to_damage_factor = 0.05f; // Nobody likes a magic number.
         const float vehicle_mass_kg = to_kilogram( veh.total_mass() );
 
-        for( const int &w : wheel_indices ) {
-            const tripoint wheel_p = veh.global_part_pos3( w );
+        for( const int vp_wheel_idx : wheel_indices ) {
+            vehicle_part &vp_wheel = veh.part( vp_wheel_idx );
+            const vpart_info &vpi_wheel = vp_wheel.info();
+            const tripoint wheel_p = veh.global_part_pos3( vp_wheel );
             if( one_in( 2 ) && displace_water( wheel_p ) ) {
                 sounds::sound( wheel_p, 4,  sounds::sound_t::movement, _( "splash!" ), false,
                                "environment", "splash" );
             }
 
-            veh.handle_trap( wheel_p, w );
-            if( !has_flag( ter_furn_flag::TFLAG_SEALED, wheel_p ) ) {
-                const float wheel_area =  veh.part( w ).wheel_area();
+            veh.handle_trap( wheel_p, vp_wheel );
+            // dont use vp_wheel or vp_wheel_idx below this - handle_trap might've removed it from parts
 
+            if( !has_flag( ter_furn_flag::TFLAG_SEALED, wheel_p ) ) {
                 // Damage is calculated based on the weight of the vehicle,
                 // The area of it's wheels, and the area of the wheel running over the items.
                 // This number is multiplied by weight_to_damage_factor to get reasonable results, damage-wise.
-                const int wheel_damage = static_cast<int>( ( ( wheel_area / vehicle_grounded_wheel_area ) *
-                                         vehicle_mass_kg ) * weight_to_damage_factor );
+                const int wheel_damage = vpi_wheel.wheel_area() / vehicle_grounded_wheel_area *
+                                         vehicle_mass_kg * weight_to_damage_factor;
 
                 //~ %1$s: vehicle name
                 smash_items( wheel_p, wheel_damage, string_format( _( "weight of %1$s" ), veh.disp_name() ) );

src/vehicle.h

@@ -1721,7 +1721,7 @@ class vehicle
                                       bool just_detect, bool bash_floor );
 
         // Process the trap beneath
-        void handle_trap( const tripoint &p, int part );
+        void handle_trap( const tripoint &p, vehicle_part &vp_wheel );
         void activate_magical_follow();
         void activate_animal_follow();
         /**

src/vehicle_move.cpp

@@ -1201,10 +1201,10 @@ veh_collision vehicle::part_collision( int part, const tripoint &p,
     return ret;
 }
 
-void vehicle::handle_trap( const tripoint &p, int part )
+void vehicle::handle_trap( const tripoint &p, vehicle_part &vp_wheel )
 {
-    int pwh = part_with_feature( part, VPFLAG_WHEEL, true );
-    if( pwh < 0 ) {
+    if( !vp_wheel.info().has_flag( VPFLAG_WHEEL ) ) {
+        debugmsg( "vehicle::handle_trap called on non-WHEEL part" );
         return;
     }
     map &here = get_map();
@@ -1214,7 +1214,7 @@ void vehicle::handle_trap( const tripoint &p, int part )
         // If the trap doesn't exist, we can't interact with it, so just return
         return;
     }
-    vehicle_handle_trap_data veh_data = tr.vehicle_data;
+    const vehicle_handle_trap_data &veh_data = tr.vehicle_data;
 
     if( veh_data.is_falling ) {
         return;
@@ -1226,9 +1226,9 @@ void vehicle::handle_trap( const tripoint &p, int part )
     if( seen ) {
         if( known ) {
             //~ %1$s: name of the vehicle; %2$s: name of the related vehicle part; %3$s: trap name
-            add_msg( m_bad, _( "The %1$s's %2$s runs over %3$s." ), name, parts[ part ].name(), tr.name() );
+            add_msg( m_bad, _( "The %1$s's %2$s runs over %3$s." ), name, vp_wheel.name(), tr.name() );
         } else {
-            add_msg( m_bad, _( "The %1$s's %2$s runs over something." ), name, parts[ part ].name() );
+            add_msg( m_bad, _( "The %1$s's %2$s runs over something." ), name, vp_wheel.name() );
         }
     }
 
@@ -1242,7 +1242,6 @@ void vehicle::handle_trap( const tripoint &p, int part )
             explosion_handler::explosion( source, p, veh_data.damage, 0.5f, false, veh_data.shrapnel );
         } else {
             // Hit the wheel directly since it ran right over the trap.
-            vehicle_part &vp_wheel = parts[part];
             damage_direct( here, vp_wheel, veh_data.damage );
         }
         bool still_has_trap = true;