Refactor moving vehicle picking into map.cpp

src/map.cpp

@@ -1122,6 +1122,41 @@ bool map::deregister_vehicle_zone( zone_data &zone ) const
     return false;
 }
 
+std::set<tripoint_bub_ms> map::get_moving_vehicle_targets( const Creature &z, int max_range )
+{
+    const tripoint_bub_ms zpos( z.pos() );
+    std::set<tripoint_bub_ms> priority;
+    std::set<tripoint_bub_ms> visible;
+    for( wrapped_vehicle &v : get_vehicles() ) {
+        if( !v.v->is_moving() ) {
+            continue;
+        }
+        if( !fov_3d && v.pos.z != zpos.z() ) {
+            continue;
+        }
+        if( rl_dist( zpos, tripoint_bub_ms( v.pos ) ) > max_range + 40 ) {
+            continue; // coarse distance filter, 40 = ~24 * sqrt(2) - rough max diameter of a vehicle
+        }
+        for( const vpart_reference &vpr : v.v->get_all_parts() ) {
+            const tripoint_bub_ms vppos = static_cast<tripoint_bub_ms>( vpr.pos() );
+            if( rl_dist( zpos, vppos ) > max_range ) {
+                continue;
+            }
+            if( !z.sees( vppos ) ) {
+                continue;
+            }
+            if( vpr.has_feature( VPFLAG_CONTROLS ) ||
+                vpr.has_feature( VPFLAG_ENGINE ) ||
+                vpr.has_feature( VPFLAG_WHEEL ) ) {
+                priority.emplace( vppos );
+            } else {
+                visible.emplace( vppos );
+            }
+        }
+    }
+    return !priority.empty() ? priority : visible;
+}
+
 // 3D vehicle functions
 
 VehicleList map::get_vehicles( const tripoint &start, const tripoint &end )

src/map.h

@@ -675,6 +675,10 @@ class map
         std::vector<zone_data *> get_vehicle_zones( int zlev );
         void register_vehicle_zone( vehicle *, int zlev );
         bool deregister_vehicle_zone( zone_data &zone ) const;
+        // returns a list of tripoints which contain parts from moving vehicles within \p max_range
+        // distance from \p source position, if any parts are CONTROLS, ENGINE or WHEELS returns a
+        // list of tripoints with exclusively such parts instead. Used for monster gun actor targeting.
+        std::set<tripoint_bub_ms> get_moving_vehicle_targets( const Creature &source, int max_range );
 
         // Removes vehicle from map and returns it in unique_ptr
         std::unique_ptr<vehicle> detach_vehicle( vehicle *veh );

src/mattack_actors.cpp

@@ -32,9 +32,7 @@
 #include "rng.h"
 #include "sounds.h"
 #include "translations.h"
-#include "vehicle.h"
 #include "viewer.h"
-#include "veh_type.h"
 
 
 static const efftype_id effect_badpoison( "badpoison" );
@@ -833,27 +831,6 @@ int gun_actor::get_max_range()  const
     return max_range;
 }
 
-static vehicle *find_target_vehicle( monster &z, int range )
-{
-    map &here = get_map();
-    vehicle *chosen = nullptr;
-    for( wrapped_vehicle &v : here.get_vehicles() ) {
-        if( !z.sees( v.pos ) ) {
-            continue;
-        }
-        if( !fov_3d && v.pos.z != z.pos().z ) {
-            continue;
-        }
-        int new_dist = rl_dist( z.pos(), v.pos );
-        if( v.v->velocity != 0 && new_dist < range ) {
-            chosen = v.v;
-            range = new_dist;
-        }
-    }
-    return chosen;
-}
-
-
 bool gun_actor::call( monster &z ) const
 {
     Creature *target;
@@ -878,47 +855,22 @@ bool gun_actor::call( monster &z ) const
         aim_at = target->pos();
     } else {
         target = z.attack_target();
+        aim_at = target ? target->pos() : tripoint_zero;
         if( !target || !z.sees( *target ) || ( !target->is_monster() && !z.aggro_character ) ) {
-            //return false;
             if( !target_moving_vehicles ) {
                 return false;
             }
-            //No living targets, try to find a moving car
-            untargeted = true;
-            vehicle *veh = find_target_vehicle( z, get_max_range() );
-            if( !veh ) {
-                return false;
-            }
-            std::vector<tripoint> valid_targets;
-            std::vector<tripoint> visible_points;
-            for( const tripoint &p : veh->get_points() ) {
-                if( !z.sees( p ) ) {
-                    continue;
-                }
-                visible_points.push_back( p );
-                for( const vpart_reference &vp : veh->get_all_parts() ) {
-                    if( vp.pos() != p ) {
-                        continue;
-                    }
-                    if( veh->part_with_feature( vp.part_index(), VPFLAG_CONTROLS, true ) >= 0 &&
-                        veh->part_with_feature( vp.part_index(), VPFLAG_ENGINE, true ) >= 0 &&
-                        veh->part_with_feature( vp.part_index(), VPFLAG_WHEEL, true ) >= 0 ) {
-                        valid_targets.push_back( p );
-                        break;
-                    }
-                }
-            }
-            if( !valid_targets.empty() ) {
-                aim_at = random_entry( valid_targets, tripoint_zero );
-            } else if( !visible_points.empty() ) {
-                aim_at = random_entry( visible_points, tripoint_zero );
-            } else {
+            untargeted = true; // no living targets, try to find moving car parts
+            const std::set<tripoint_bub_ms> moving_veh_parts = get_map()
+                    .get_moving_vehicle_targets( z, get_max_range() );
+            if( moving_veh_parts.empty() ) {
                 return false;
             }
+            aim_at = random_entry( moving_veh_parts, tripoint_bub_ms() ).raw();
         }
     }
 
-    int dist = rl_dist( z.pos(), aim_at );
+    const int dist = rl_dist( z.pos(), aim_at );
     if( target ) {
         add_msg_debug( debugmode::DF_MATTACK, "Target %s at range %d", target->disp_name(), dist );
     } else {