Feature: Non-rectangular sparse station catchment area.

src/economy.cpp

@@ -1049,11 +1049,6 @@ static uint DeliverGoodsToIndustry(const Station *st, CargoID cargo_type, uint n
 
 		if (ind->index == source) continue;
 
-		if (!_settings_game.station.serve_neutral_industries) {
-			/* If this industry is only served by its neutral station, check it's us. */
-			if (ind->neutral_station != NULL && ind->neutral_station != st) continue;
-		}
-
 		uint cargo_index;
 		for (cargo_index = 0; cargo_index < lengthof(ind->accepts_cargo); cargo_index++) {
 			if (cargo_type == ind->accepts_cargo[cargo_index]) break;

src/industry.h

@@ -63,6 +63,7 @@ struct Industry : IndustryPool::PoolItem<&_industry_pool> {
 	byte was_cargo_delivered;           ///< flag that indicate this has been the closest industry chosen for cargo delivery by a station. see DeliverGoodsToIndustry
 
 	PartOfSubsidyByte part_of_subsidy;  ///< NOSAVE: is this industry a source/destination of a subsidy?
+	StationList stations_near;          ///< NOSAVE: List of nearby stations.
 
 	OwnerByte founder;                  ///< Founder of the industry
 	Date construction_date;             ///< Date of the construction of the industry

src/industry_cmd.cpp

@@ -182,6 +182,10 @@ Industry::~Industry()
 
 	DeleteSubsidyWith(ST_INDUSTRY, this->index);
 	CargoPacket::InvalidateAllFrom(ST_INDUSTRY, this->index);
+
+	for (Station *st : this->stations_near) {
+		st->industries_near.erase(this);
+	}
 }
 
 /**
@@ -191,7 +195,6 @@ Industry::~Industry()
 void Industry::PostDestructor(size_t index)
 {
 	InvalidateWindowData(WC_INDUSTRY_DIRECTORY, 0, 0);
-	Station::RecomputeIndustriesNearForAll();
 }
 
 
@@ -516,14 +519,6 @@ static bool TransportIndustryGoods(TileIndex tile)
 	const IndustrySpec *indspec = GetIndustrySpec(i->type);
 	bool moved_cargo = false;
 
-	StationFinder stations(i->location);
-	StationList neutral;
-
-	if (i->neutral_station != NULL && !_settings_game.station.serve_neutral_industries) {
-		/* Industry has a neutral station. Use it and ignore any other nearby stations. */
-		neutral.insert(i->neutral_station);
-	}
-
 	for (uint j = 0; j < lengthof(i->produced_cargo_waiting); j++) {
 		uint cw = min(i->produced_cargo_waiting[j], 255);
 		if (cw > indspec->minimal_cargo && i->produced_cargo[j] != CT_INVALID) {
@@ -534,7 +529,7 @@ static bool TransportIndustryGoods(TileIndex tile)
 
 			i->this_month_production[j] += cw;
 
-			uint am = MoveGoodsToStation(i->produced_cargo[j], cw, ST_INDUSTRY, i->index, neutral.size() != 0 ? &neutral : stations.GetStations());
+			uint am = MoveGoodsToStation(i->produced_cargo[j], cw, ST_INDUSTRY, i->index, &i->stations_near);
 			i->this_month_transported[j] += am;
 
 			moved_cargo |= (am != 0);
@@ -1650,6 +1645,37 @@ static void AdvertiseIndustryOpening(const Industry *ind)
 	Game::NewEvent(new ScriptEventIndustryOpen(ind->index));
 }
 
+/**
+ * Populate an industry's list of nearby stations, and if it accepts any cargo, also
+ * add the industry to each station's nearby industry list.
+ * @param ind Industry
+ */
+static void PopulateStationsNearby(Industry *ind)
+{
+	if (ind->neutral_station != NULL && !_settings_game.station.serve_neutral_industries) {
+		/* Industry has a neutral station. Use it and ignore any other nearby stations. */
+		ind->stations_near.insert(ind->neutral_station);
+		ind->neutral_station->industries_near.clear();
+		ind->neutral_station->industries_near.insert(ind);
+		return;
+	}
+
+	/* Get our list of nearby stations. */
+	FindStationsAroundTiles(ind->location, &ind->stations_near, false);
+
+	/* Test if industry can accept cargo */
+	uint cargo_index;
+	for (cargo_index = 0; cargo_index < lengthof(ind->accepts_cargo); cargo_index++) {
+		if (ind->accepts_cargo[cargo_index] != CT_INVALID) break;
+	}
+	if (cargo_index >= lengthof(ind->accepts_cargo)) return;
+
+	/* Cargo is accepted, add industry to nearby stations nearby industry list. */
+	for (Station *st : ind->stations_near) {
+		st->industries_near.insert(ind);
+	}
+}
+
 /**
  * Put an industry on the map.
  * @param i       Just allocated poolitem, mostly empty.
@@ -1823,7 +1849,7 @@ static void DoCreateNewIndustry(Industry *i, TileIndex tile, IndustryType type,
 	}
 	InvalidateWindowData(WC_INDUSTRY_DIRECTORY, 0, 0);
 
-	Station::RecomputeIndustriesNearForAll();
+	if (!_generating_world) PopulateStationsNearby(i);
 }
 
 /**
@@ -2428,11 +2454,7 @@ static void CanCargoServiceIndustry(CargoID cargo, Industry *ind, bool *c_accept
  */
 static int WhoCanServiceIndustry(Industry *ind)
 {
-	/* Find all stations within reach of the industry */
-	StationList stations;
-	FindStationsAroundTiles(ind->location, &stations);
-
-	if (stations.size() == 0) return 0; // No stations found at all => nobody services
+	if (ind->stations_near.size() == 0) return 0; // No stations found at all => nobody services
 
 	const Vehicle *v;
 	int result = 0;
@@ -2468,7 +2490,7 @@ static int WhoCanServiceIndustry(Industry *ind)
 				/* Same cargo produced by industry is dropped here => not serviced by vehicle v */
 				if ((o->GetUnloadType() & OUFB_UNLOAD) && !c_accepts) break;
 
-				if (stations.find(st) != stations.end()) {
+				if (ind->stations_near.find(st) != ind->stations_near.end()) {
 					if (v->owner == _local_company) return 2; // Company services industry
 					result = 1; // Competitor services industry
 				}

src/saveload/afterload.cpp

@@ -285,7 +285,6 @@ static void InitializeWindowsAndCaches()
 
 	GroupStatistics::UpdateAfterLoad();
 
-	Station::RecomputeIndustriesNearForAll();
 	RebuildSubsidisedSourceAndDestinationCache();
 
 	/* Towns have a noise controlled number of airports system
@@ -3104,6 +3103,9 @@ bool AfterLoadGame()
 		FOR_ALL_INDUSTRIES(ind) if (ind->neutral_station != NULL) ind->neutral_station->industry = ind;
 	}
 
+	/* Compute station catchment areas. This is needed here in case UpdateStationAcceptance is called below. */
+	Station::RecomputeCatchmentForAll();
+
 	/* Station acceptance is some kind of cache */
 	if (IsSavegameVersionBefore(SLV_127)) {
 		Station *st;

src/script/api/script_industry.cpp

@@ -132,9 +132,7 @@
 	if (!IsValidIndustry(industry_id)) return -1;
 
 	Industry *ind = ::Industry::Get(industry_id);
-	StationList stations;
-	::FindStationsAroundTiles(ind->location, &stations);
-	return (int32)stations.size();
+	return (int32)ind->stations_near.size();
 }
 
 /* static */ int32 ScriptIndustry::GetDistanceManhattanToTile(IndustryID industry_id, TileIndex tile)

src/settings.cpp

@@ -1302,7 +1302,7 @@ static bool ChangeMaxHeightLevel(int32 p1)
 
 static bool StationCatchmentChanged(int32 p1)
 {
-	Station::RecomputeIndustriesNearForAll();
+	Station::RecomputeCatchmentForAll();
 	return true;
 }
 

src/station.cpp

@@ -23,6 +23,7 @@
 #include "station_base.h"
 #include "roadstop_base.h"
 #include "industry.h"
+#include "town.h"
 #include "core/random_func.hpp"
 #include "linkgraph/linkgraph.h"
 #include "linkgraph/linkgraphschedule.h"
@@ -119,6 +120,9 @@ Station::~Station()
 		}
 	}
 
+	/* Remove station from industries and towns that reference it. */
+	this->RemoveFromAllNearbyLists();
+
 	/* Clear the persistent storage. */
 	delete this->airport.psa;
 
@@ -261,6 +265,39 @@ void Station::MarkTilesDirty(bool cargo_change) const
 	return length;
 }
 
+/**
+ * Get the catchment size of an individual station tile.
+ * @param tile Station tile to get catchment size of.
+ * @param st Associated station of station tile.
+ * @pre IsTileType(tile, MP_STATION)
+ * @return The catchment size of the station tile.
+ */
+static uint GetTileCatchmentRadius(TileIndex tile, const Station *st)
+{
+	assert(IsTileType(tile, MP_STATION));
+
+	if (_settings_game.station.modified_catchment) {
+		switch (GetStationType(tile)) {
+			case STATION_RAIL:    return CA_TRAIN;
+			case STATION_OILRIG:  return CA_UNMODIFIED;
+			case STATION_AIRPORT: return st->airport.GetSpec()->catchment;
+			case STATION_TRUCK:   return CA_TRUCK;
+			case STATION_BUS:     return CA_BUS;
+			case STATION_DOCK:    return CA_DOCK;
+
+			default: NOT_REACHED();
+			case STATION_BUOY:
+			case STATION_WAYPOINT: return CA_NONE;
+		}
+	} else {
+		switch (GetStationType(tile)) {
+			default:               return CA_UNMODIFIED;
+			case STATION_BUOY:
+			case STATION_WAYPOINT: return CA_NONE;
+		}
+	}
+}
+
 /**
  * Determines the catchment radius of the station
  * @return The radius
@@ -305,85 +342,127 @@ Rect Station::GetCatchmentRect() const
 	return ret;
 }
 
-/** Rect and pointer to IndustryVector */
-struct RectAndIndustryVector {
-	Rect rect;                     ///< The rectangle to search the industries in.
-	IndustryList *industries_near; ///< The nearby industries.
-};
-
 /**
- * Callback function for Station::RecomputeIndustriesNear()
- * Tests whether tile is an industry and possibly adds
- * the industry to station's industries_near list.
- * @param ind_tile tile to check
- * @param user_data pointer to RectAndIndustryVector
- * @return always false, we want to search all tiles
+ * Add nearby industry to station's industries_near list if it accepts cargo.
+ * @param ind Industry
+ * @param st Station
  */
-static bool FindIndustryToDeliver(TileIndex ind_tile, void *user_data)
+static void AddIndustryToDeliver(Industry *ind, Station *st)
 {
-	/* Only process industry tiles */
-	if (!IsTileType(ind_tile, MP_INDUSTRY)) return false;
-
-	RectAndIndustryVector *riv = (RectAndIndustryVector *)user_data;
-	Industry *ind = Industry::GetByTile(ind_tile);
-
 	/* Don't check further if this industry is already in the list */
-	if (riv->industries_near->find(ind) != riv->industries_near->end()) return false;
-
-	/* Only process tiles in the station acceptance rectangle */
-	int x = TileX(ind_tile);
-	int y = TileY(ind_tile);
-	if (x < riv->rect.left || x > riv->rect.right || y < riv->rect.top || y > riv->rect.bottom) return false;
+	if (st->industries_near.find(ind) != st->industries_near.end()) return;
 
 	/* Include only industries that can accept cargo */
 	uint cargo_index;
 	for (cargo_index = 0; cargo_index < lengthof(ind->accepts_cargo); cargo_index++) {
 		if (ind->accepts_cargo[cargo_index] != CT_INVALID) break;
 	}
-	if (cargo_index >= lengthof(ind->accepts_cargo)) return false;
+	if (cargo_index >= lengthof(ind->accepts_cargo)) return;
 
-	riv->industries_near->insert(ind);
+	st->industries_near.insert(ind);
+}
+
+/**
+ * Remove this station from the nearby stations lists of all towns and industries.
+ */
+void Station::RemoveFromAllNearbyLists()
+{
+	Town *t;
+	FOR_ALL_TOWNS(t) { t->stations_near.erase(this); }
+	Industry *i;
+	FOR_ALL_INDUSTRIES(i) { i->stations_near.erase(this); }
+}
 
+/**
+ * Test if the given town ID is covered by our catchment area.
+ * This is used when removing a house tile to determine if it was the last house tile
+ * within our catchment.
+ * @param t TownID to test.
+ * @return true if at least one house tile of TownID is covered.
+ */
+bool Station::CatchmentCoversTown(TownID t) const
+{
+	BitmapTileIterator it(this->catchment_tiles);
+	for (TileIndex tile = it; tile != INVALID_TILE; tile = ++it) {
+		if (IsTileType(tile, MP_HOUSE) && GetTownIndex(tile) == t) return true;
+	}
 	return false;
 }
 
 /**
- * Recomputes Station::industries_near, list of industries possibly
- * accepting cargo in station's catchment radius
+ * Recompute tiles covered in our catchment area.
+ * This will additionally recompute nearby towns and industries.
  */
-void Station::RecomputeIndustriesNear()
+void Station::RecomputeCatchment()
 {
 	this->industries_near.clear();
-	if (this->rect.IsEmpty()) return;
+	this->RemoveFromAllNearbyLists();
+
+	if (this->rect.IsEmpty()) {
+		this->catchment_tiles.Reset();
+		return;
+	}
+	this->catchment_tiles.Initialize(GetCatchmentRect());
 
 	if (!_settings_game.station.serve_neutral_industries && this->industry != NULL) {
 		/* Station is associated with an industry, so we only need to deliver to that industry. */
+		TILE_AREA_LOOP(tile, this->industry->location) {
+			if (IsTileType(tile, MP_INDUSTRY) && GetIndustryIndex(tile) == this->industry->index) {
+				this->catchment_tiles.SetTile(tile);
+			}
+		}
+		/* The industry's stations_near may have been computed before its neutral station was built so clear and re-add here. */
+		for (Station *st : this->industry->stations_near) {
+			st->industries_near.erase(this->industry);
+		}
+		this->industry->stations_near.clear();
+		this->industry->stations_near.insert(this);
 		this->industries_near.insert(this->industry);
 		return;
 	}
 
-	RectAndIndustryVector riv = {
-		this->GetCatchmentRect(),
-		&this->industries_near
-	};
+	/* Loop finding all station tiles */
+	TileArea ta(TileXY(this->rect.left, this->rect.top), TileXY(this->rect.right, this->rect.bottom));
+	TILE_AREA_LOOP(tile, ta) {
+		if (!IsTileType(tile, MP_STATION) || GetStationIndex(tile) != this->index) continue;
+
+		uint r = GetTileCatchmentRadius(tile, this);
+		if (r == CA_NONE) continue;
+
+		/* This tile sub-loop doesn't need to test any tiles, they are simply added to the catchment set. */
+		TileArea ta2(TileXY(max<int>(TileX(tile) - r, 0), max<int>(TileY(tile) - r, 0)), TileXY(min<int>(TileX(tile) + r, MapMaxX()), min<int>(TileY(tile) + r, MapMaxY())));
+		TILE_AREA_LOOP(tile2, ta2) this->catchment_tiles.SetTile(tile2);
+	}
 
-	/* Compute maximum extent of acceptance rectangle wrt. station sign */
-	TileIndex start_tile = this->xy;
-	uint max_radius = max(
-		max(DistanceManhattan(start_tile, TileXY(riv.rect.left,  riv.rect.top)), DistanceManhattan(start_tile, TileXY(riv.rect.left,  riv.rect.bottom))),
-		max(DistanceManhattan(start_tile, TileXY(riv.rect.right, riv.rect.top)), DistanceManhattan(start_tile, TileXY(riv.rect.right, riv.rect.bottom)))
-	);
+	/* Search catchment tiles for towns and industries */
+	BitmapTileIterator it(this->catchment_tiles);
+	for (TileIndex tile = it; tile != INVALID_TILE; tile = ++it) {
+		if (IsTileType(tile, MP_HOUSE)) {
+			Town *t = Town::GetByTile(tile);
+			t->stations_near.insert(this);
+		}
+		if (IsTileType(tile, MP_INDUSTRY)) {
+			Industry *i = Industry::GetByTile(tile);
+
+			/* Ignore industry if it has a neutral station. It already can't be this station. */
+			if (!_settings_game.station.serve_neutral_industries && i->neutral_station != NULL) continue;
+
+			i->stations_near.insert(this);
 
-	CircularTileSearch(&start_tile, 2 * max_radius + 1, &FindIndustryToDeliver, &riv);
+			/* Add if we can deliver to this industry as well */
+			AddIndustryToDeliver(i, this);
+		}
+	}
 }
 
 /**
- * Recomputes Station::industries_near for all stations
+ * Recomputes catchment of all stations.
+ * This will additionally recompute nearby stations for all towns and industries.
  */
-/* static */ void Station::RecomputeIndustriesNearForAll()
+/* static */ void Station::RecomputeCatchmentForAll()
 {
 	Station *st;
-	FOR_ALL_STATIONS(st) st->RecomputeIndustriesNear();
+	FOR_ALL_STATIONS(st) { st->RecomputeCatchment(); }
 }
 
 /************************************************************************/

src/station_base.h

@@ -19,6 +19,7 @@
 #include "industry_type.h"
 #include "linkgraph/linkgraph_type.h"
 #include "newgrf_storage.h"
+#include "bitmap_type.h"
 #include <map>
 #include <set>
 
@@ -467,6 +468,8 @@ public:
 
 	IndustryType indtype;   ///< Industry type to get the name from
 
+	BitmapTileArea catchment_tiles; ///< NOSAVE: Set of individual tiles covered by catchment area
+
 	StationHadVehicleOfTypeByte had_vehicle_of_type;
 
 	byte time_since_load;
@@ -493,11 +496,18 @@ public:
 
 	/* virtual */ uint GetPlatformLength(TileIndex tile, DiagDirection dir) const;
 	/* virtual */ uint GetPlatformLength(TileIndex tile) const;
-	void RecomputeIndustriesNear();
-	static void RecomputeIndustriesNearForAll();
+	void RecomputeCatchment();
+	static void RecomputeCatchmentForAll();
 
 	uint GetCatchmentRadius() const;
 	Rect GetCatchmentRect() const;
+	bool CatchmentCoversTown(TownID t) const;
+	void RemoveFromAllNearbyLists();
+
+	inline bool TileIsInCatchment(TileIndex tile) const
+	{
+		return this->catchment_tiles.HasTile(tile);
+	}
 
 	/* virtual */ inline bool TileBelongsToRailStation(TileIndex tile) const
 	{

src/station_cmd.cpp

@@ -527,7 +527,7 @@ CargoArray GetProductionAroundTiles(TileIndex tile, int w, int h, int rad)
  * @param always_accepted bitmask of cargo accepted by houses and headquarters; can be NULL
  * @param ind Industry associated with neutral station (e.g. oil rig) or NULL
  */
-CargoArray GetAcceptanceAroundTiles(TileIndex tile, int w, int h, int rad, CargoTypes *always_accepted, const Industry *ind)
+CargoArray GetAcceptanceAroundTiles(TileIndex tile, int w, int h, int rad, CargoTypes *always_accepted)
 {
 	CargoArray acceptance;
 	if (always_accepted != NULL) *always_accepted = 0;
@@ -551,14 +551,9 @@ CargoArray GetAcceptanceAroundTiles(TileIndex tile, int w, int h, int rad, Cargo
 		for (int xc = x1; xc != x2; xc++) {
 			TileIndex tile = TileXY(xc, yc);
 
-			if (!_settings_game.station.serve_neutral_industries) {
-				if (ind != NULL) {
-					if (!IsTileType(tile, MP_INDUSTRY)) continue;
-					if (Industry::GetByTile(tile) != ind) continue;
-				} else {
-					if (IsTileType(tile, MP_INDUSTRY) && Industry::GetByTile(tile)->neutral_station != NULL) continue;
-				}
-			}
+			/* Ignore industry if it has a neutral station. */
+			if (!_settings_game.station.serve_neutral_industries && IsTileType(tile, MP_INDUSTRY) && Industry::GetByTile(tile)->neutral_station != NULL) continue;
+
 			AddAcceptedCargo(tile, acceptance, always_accepted);
 		}
 	}
@@ -566,6 +561,24 @@ CargoArray GetAcceptanceAroundTiles(TileIndex tile, int w, int h, int rad, Cargo
 	return acceptance;
 }
 
+/**
+ * Get the acceptance of cargoes around the station in.
+ * @param st Station to get acceptance of.
+ * @param always_accepted bitmask of cargo accepted by houses and headquarters; can be NULL
+ */
+static CargoArray GetAcceptanceAroundStation(const Station *st, CargoTypes *always_accepted)
+{
+	CargoArray acceptance;
+	if (always_accepted != NULL) *always_accepted = 0;
+
+	BitmapTileIterator it(st->catchment_tiles);
+	for (TileIndex tile = it; tile != INVALID_TILE; tile = ++it) {
+		AddAcceptedCargo(tile, acceptance, always_accepted);
+	}
+
+	return acceptance;
+}
+
 /**
  * Update the acceptance for a station.
  * @param st Station to update
@@ -579,14 +592,7 @@ void UpdateStationAcceptance(Station *st, bool show_msg)
 	/* And retrieve the acceptance. */
 	CargoArray acceptance;
 	if (!st->rect.IsEmpty()) {
-		acceptance = GetAcceptanceAroundTiles(
-			TileXY(st->rect.left, st->rect.top),
-			st->rect.right  - st->rect.left + 1,
-			st->rect.bottom - st->rect.top  + 1,
-			st->GetCatchmentRadius(),
-			&st->always_accepted,
-			_settings_game.station.serve_neutral_industries ? NULL : st->industry
-		);
+		acceptance = GetAcceptanceAroundStation(st, &st->always_accepted);
 	}
 
 	/* Adjust in case our station only accepts fewer kinds of goods */
@@ -736,7 +742,7 @@ static void DeleteStationIfEmpty(BaseStation *st)
 void Station::AfterStationTileSetChange(bool adding, StationType type)
 {
 	this->UpdateVirtCoord();
-	this->RecomputeIndustriesNear();
+	this->RecomputeCatchment();
 	DirtyCompanyInfrastructureWindows(this->owner);
 	if (adding) InvalidateWindowData(WC_STATION_LIST, this->owner, 0);
 
@@ -1643,7 +1649,7 @@ CommandCost CmdRemoveFromRailStation(TileIndex start, DoCommandFlag flags, uint3
 
 		if (st->train_station.tile == INVALID_TILE) SetWindowWidgetDirty(WC_STATION_VIEW, st->index, WID_SV_TRAINS);
 		st->MarkTilesDirty(false);
-		st->RecomputeIndustriesNear();
+		st->RecomputeCatchment();
 	}
 
 	/* Now apply the rail cost to the number that we deleted */
@@ -1726,7 +1732,7 @@ static CommandCost RemoveRailStation(TileIndex tile, DoCommandFlag flags)
 	Station *st = Station::GetByTile(tile);
 	CommandCost cost = RemoveRailStation(st, flags, _price[PR_CLEAR_STATION_RAIL]);
 
-	if (flags & DC_EXEC) st->RecomputeIndustriesNear();
+	if (flags & DC_EXEC) st->RecomputeCatchment();
 
 	return cost;
 }
@@ -3215,9 +3221,8 @@ void TriggerWatchedCargoCallbacks(Station *st)
 	if (cargoes == 0) return;
 
 	/* Loop over all houses in the catchment. */
-	Rect r = st->GetCatchmentRect();
-	TileArea ta(TileXY(r.left, r.top), TileXY(r.right, r.bottom));
-	TILE_AREA_LOOP(tile, ta) {
+	BitmapTileIterator it(st->catchment_tiles);
+	for (TileIndex tile = it; tile != INVALID_TILE; tile = ++it) {
 		if (IsTileType(tile, MP_HOUSE)) {
 			WatchedCargoCallback(tile, cargoes);
 		}
@@ -3623,7 +3628,7 @@ void IncreaseStats(Station *st, const Vehicle *front, StationID next_station_id)
 			 * As usage is not such an important figure anyway we just
 			 * ignore the additional cargo then.*/
 			IncreaseStats(st, v->cargo_type, next_station_id, v->refit_cap,
-				min(v->refit_cap, v->cargo.StoredCount()), EUM_INCREASE);
+					min(v->refit_cap, v->cargo.StoredCount()), EUM_INCREASE);
 		}
 	}
 }
@@ -3789,57 +3794,63 @@ CommandCost CmdRenameStation(TileIndex tile, DoCommandFlag flags, uint32 p1, uin
 	return CommandCost();
 }
 
+static void AddNearbyStationsByCatchment(TileIndex tile, StationList *stations, StationList &nearby)
+{
+	for (Station *st : nearby) {
+		if (st->TileIsInCatchment(tile)) stations->insert(st);
+	}
+}
+
 /**
  * Find all stations around a rectangular producer (industry, house, headquarter, ...)
  *
  * @param location The location/area of the producer
  * @param stations The list to store the stations in
+ * @param use_nearby Use nearby station list of industry/town associated with location.tile
  */
-void FindStationsAroundTiles(const TileArea &location, StationList *stations)
+void FindStationsAroundTiles(const TileArea &location, StationList *stations, bool use_nearby)
 {
-	/* area to search = producer plus station catchment radius */
-	uint max_rad = (_settings_game.station.modified_catchment ? MAX_CATCHMENT : CA_UNMODIFIED);
+	if (use_nearby) {
+		/* Industries and towns maintain a list of nearby stations */
+		if (IsTileType(location.tile, MP_INDUSTRY)) {
+			/* Industry nearby stations are already filtered by catchment. */
+			stations = &Industry::GetByTile(location.tile)->stations_near;
+			return;
+		} else if (IsTileType(location.tile, MP_HOUSE)) {
+			/* Town nearby stations need to be filtered per tile. */
+			assert(location.w == 1 && location.h == 1);
+			AddNearbyStationsByCatchment(location.tile, stations, Town::GetByTile(location.tile)->stations_near);
+			return;
+		}
+	}
 
+	/* Not using, or don't have a nearby stations list, so we need to scan. */
 	uint x = TileX(location.tile);
 	uint y = TileY(location.tile);
 
-	uint min_x = (x > max_rad) ? x - max_rad : 0;
-	uint max_x = x + location.w + max_rad;
-	uint min_y = (y > max_rad) ? y - max_rad : 0;
-	uint max_y = y + location.h + max_rad;
+	std::set<StationID> seen_stations;
 
-	IndustryID ind = IsTileType(location.tile, MP_INDUSTRY) ? GetIndustryIndex(location.tile) : INVALID_INDUSTRY;
-
-	if (min_x == 0 && _settings_game.construction.freeform_edges) min_x = 1;
-	if (min_y == 0 && _settings_game.construction.freeform_edges) min_y = 1;
-	if (max_x >= MapSizeX()) max_x = MapSizeX() - 1;
-	if (max_y >= MapSizeY()) max_y = MapSizeY() - 1;
-
-	for (uint cy = min_y; cy < max_y; cy++) {
-		for (uint cx = min_x; cx < max_x; cx++) {
-			TileIndex cur_tile = TileXY(cx, cy);
-			if (!IsTileType(cur_tile, MP_STATION)) continue;
-
-			Station *st = Station::GetByTile(cur_tile);
-			/* st can be NULL in case of waypoints */
-			if (st == NULL) continue;
+	/* Scan an area around the building covering the maximum possible station
+	 * to find the possible nearby stations. */
+	uint max_c = _settings_game.station.modified_catchment ? MAX_CATCHMENT : CA_UNMODIFIED;
+	TileArea ta(TileXY(max<int>(0, x - max_c), max<int>(0, y - max_c)), TileXY(min<int>(MapMaxX(), x + location.w + max_c), min<int>(MapMaxY(), y + location.h + max_c)));
+	TILE_AREA_LOOP(tile, ta) {
+		if (IsTileType(tile, MP_STATION)) seen_stations.insert(GetStationIndex(tile));
+	}
 
-			/* Check if neutral station is attached to us */
-			if (!_settings_game.station.serve_neutral_industries && st->industry != NULL && st->industry->index != ind) continue;
+	for (StationID stationid : seen_stations) {
+		Station *st = Station::GetIfValid(stationid);
+		if (st == NULL) continue; /* Waypoint */
 
-			if (_settings_game.station.modified_catchment) {
-				int rad = st->GetCatchmentRadius();
-				int rad_x = cx - x;
-				int rad_y = cy - y;
+		/* Check if station is attached to an industry */
+		if (!_settings_game.station.serve_neutral_industries && st->industry != NULL) continue;
 
-				if (rad_x < -rad || rad_x >= rad + location.w) continue;
-				if (rad_y < -rad || rad_y >= rad + location.h) continue;
+		/* Test if the tile is within the station's catchment */
+		TILE_AREA_LOOP(tile, location) {
+			if (st->TileIsInCatchment(tile)) {
+				stations->insert(st);
+				break;
 			}
-
-			/* Insert the station in the set. This will fail if it has
-			 * already been added.
-			 */
-			stations->insert(st);
 		}
 	}
 }
@@ -3950,8 +3961,8 @@ void BuildOilRig(TileIndex tile)
 	st->rect.BeforeAddTile(tile, StationRect::ADD_FORCE);
 
 	st->UpdateVirtCoord();
+	st->RecomputeCatchment();
 	UpdateStationAcceptance(st, false);
-	st->RecomputeIndustriesNear();
 }
 
 void DeleteOilRig(TileIndex tile)
@@ -3968,7 +3979,7 @@ void DeleteOilRig(TileIndex tile)
 	st->rect.AfterRemoveTile(st, tile);
 
 	st->UpdateVirtCoord();
-	st->RecomputeIndustriesNear();
+	st->RecomputeCatchment();
 	if (!st->IsInUse()) delete st;
 }
 

src/station_func.h

@@ -23,13 +23,13 @@
 
 void ModifyStationRatingAround(TileIndex tile, Owner owner, int amount, uint radius);
 
-void FindStationsAroundTiles(const TileArea &location, StationList *stations);
+void FindStationsAroundTiles(const TileArea &location, StationList *stations, bool use_nearby = true);
 
 void ShowStationViewWindow(StationID station);
 void UpdateAllStationVirtCoords();
 
 CargoArray GetProductionAroundTiles(TileIndex tile, int w, int h, int rad);
-CargoArray GetAcceptanceAroundTiles(TileIndex tile, int w, int h, int rad, CargoTypes *always_accepted = NULL, const Industry *ind = NULL);
+CargoArray GetAcceptanceAroundTiles(TileIndex tile, int w, int h, int rad, CargoTypes *always_accepted = NULL);
 
 void UpdateStationAcceptance(Station *st, bool show_msg);
 

src/subsidy.cpp

@@ -573,15 +573,11 @@ bool CheckSubsidised(CargoID cargo_type, CompanyID company, SourceType src_type,
 			if (s->cargo_type != cargo_type || s->src_type != src_type || s->src != src) continue;
 			if (s->IsAwarded() && s->awarded != company) continue;
 
-			Rect rect = st->GetCatchmentRect();
-
-			for (int y = rect.top; y <= rect.bottom; y++) {
-				for (int x = rect.left; x <= rect.right; x++) {
-					TileIndex tile = TileXY(x, y);
-					if (!IsTileType(tile, MP_HOUSE)) continue;
-					const Town *t = Town::GetByTile(tile);
-					if (t->cache.part_of_subsidy & POS_DST) towns_near.Include(t);
-				}
+			BitmapTileIterator it(st->catchment_tiles);
+			for (TileIndex tile = it; tile != INVALID_TILE; tile = ++it) {
+				if (!IsTileType(tile, MP_HOUSE)) continue;
+				const Town *t = Town::GetByTile(tile);
+				if (t->cache.part_of_subsidy & POS_DST) towns_near.Include(t);
 			}
 			break;
 		}

src/town.h

@@ -88,6 +88,7 @@ struct Town : TownPool::PoolItem<&_town_pool> {
 	CargoTypes cargo_produced;       ///< Bitmap of all cargoes produced by houses in this town.
 	AcceptanceMatrix cargo_accepted; ///< Bitmap of cargoes accepted by houses for each 4*4 map square of the town.
 	CargoTypes cargo_accepted_total; ///< NOSAVE: Bitmap of all cargoes accepted by houses in this town.
+	StationList stations_near;       ///< NOSAVE: List of nearby stations.
 
 	uint16 time_until_rebuild;     ///< time until we rebuild a house
 

src/town_cmd.cpp

@@ -446,6 +446,22 @@ uint32 GetWorldPopulation()
 	return pop;
 }
 
+/**
+ * Remove stations from nearby station list if a town is no longer in the catchment area of each.
+ * @param t Town to work on
+ */
+static void RemoveNearbyStations(Town *t)
+{
+	for (StationList::iterator it = t->stations_near.begin(); it != t->stations_near.end(); /* incremented inside loop */) {
+		const Station *st = *it;
+		if (!st->CatchmentCoversTown(t->index)) {
+			it = t->stations_near.erase(it);
+		} else {
+			++it;
+		}
+	}
+}
+
 /**
  * Helper function for house completion stages progression
  * @param tile TileIndex of the house (or parts of it) to "grow"
@@ -599,7 +615,11 @@ static void TileLoop_Town(TileIndex tile)
 		ClearTownHouse(t, tile);
 
 		/* Rebuild with another house? */
-		if (GB(r, 24, 8) >= 12) BuildTownHouse(t, tile);
+		if (GB(r, 24, 8) < 12 || !BuildTownHouse(t, tile))
+		{
+			/* House wasn't replaced, so remove it */
+			if (!_generating_world) RemoveNearbyStations(t);
+		}
 	}
 
 	cur_company.Restore();
@@ -628,6 +648,7 @@ static CommandCost ClearTile_Town(TileIndex tile, DoCommandFlag flags)
 	ChangeTownRating(t, -rating, RATING_HOUSE_MINIMUM, flags);
 	if (flags & DC_EXEC) {
 		ClearTownHouse(t, tile);
+		RemoveNearbyStations(t);
 	}
 
 	return cost;
@@ -2151,6 +2172,8 @@ static void MakeTownHouse(TileIndex t, Town *town, byte counter, byte stage, Hou
 	if (size & BUILDING_2_TILES_Y)   ClearMakeHouseTile(t + TileDiffXY(0, 1), town, counter, stage, ++type, random_bits);
 	if (size & BUILDING_2_TILES_X)   ClearMakeHouseTile(t + TileDiffXY(1, 0), town, counter, stage, ++type, random_bits);
 	if (size & BUILDING_HAS_4_TILES) ClearMakeHouseTile(t + TileDiffXY(1, 1), town, counter, stage, ++type, random_bits);
+
+	if (!_generating_world) FindStationsAroundTiles(TileArea(t, (size & BUILDING_2_TILES_X) ? 2 : 1, (size & BUILDING_2_TILES_Y) ? 2 : 1), &town->stations_near, false);
 }