Change: Deliver cargo to the closest industry first (#9536)

src/cargomonitor.cpp

@@ -149,9 +149,9 @@ void AddCargoDelivery(CargoID cargo_type, CompanyID company, uint32 amount, Sour
 	if (iter != _cargo_deliveries.end()) iter->second += amount;
 
 	/* Industry delivery. */
-	for (Industry *ind : st->industries_near) {
-		if (ind->index != dest) continue;
-		CargoMonitorID num = EncodeCargoIndustryMonitor(company, cargo_type, ind->index);
+	for (const auto &i : st->industries_near) {
+		if (i.industry->index != dest) continue;
+		CargoMonitorID num = EncodeCargoIndustryMonitor(company, cargo_type, i.industry->index);
 		CargoMonitorMap::iterator iter = _cargo_deliveries.find(num);
 		if (iter != _cargo_deliveries.end()) iter->second += amount;
 	}

src/economy.cpp

@@ -1040,9 +1040,10 @@ static uint DeliverGoodsToIndustry(const Station *st, CargoID cargo_type, uint n
 
 	uint accepted = 0;
 
-	for (Industry *ind : st->industries_near) {
+	for (const auto &i : st->industries_near) {
 		if (num_pieces == 0) break;
 
+		Industry *ind = i.industry;
 		if (ind->index == source) continue;
 
 		uint cargo_index;

src/industry_cmd.cpp

@@ -199,7 +199,7 @@ Industry::~Industry()
 	CargoPacket::InvalidateAllFrom(ST_INDUSTRY, this->index);
 
 	for (Station *st : this->stations_near) {
-		st->industries_near.erase(this);
+		st->RemoveIndustryToDeliver(this);
 	}
 }
 
@@ -1701,15 +1701,14 @@ static void PopulateStationsNearby(Industry *ind)
 		/* 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);
+		ind->neutral_station->industries_near.insert(IndustryListEntry{0, ind});
 		return;
 	}
 
 	ForAllStationsAroundTiles(ind->location, [ind](Station *st, TileIndex tile) {
 		if (!IsTileType(tile, MP_INDUSTRY) || GetIndustryIndex(tile) != ind->index) return false;
-		ind->stations_near.insert(st);
-		st->AddIndustryToDeliver(ind);
-		return true;
+		st->AddIndustryToDeliver(ind, tile);
+		return false;
 	});
 }
 
@@ -3069,7 +3068,8 @@ extern const TileTypeProcs _tile_type_industry_procs = {
 	TerraformTile_Industry,      // terraform_tile_proc
 };
 
-bool IndustryCompare::operator() (const Industry *lhs, const Industry *rhs) const
+bool IndustryCompare::operator() (const IndustryListEntry &lhs, const IndustryListEntry &rhs) const
 {
-	return lhs->index < rhs->index;
+	/* Compare by distance first and use index as a tiebreaker. */
+	return std::tie(lhs.distance, lhs.industry->index) < std::tie(rhs.distance, rhs.industry->index);
 }

src/station.cpp

@@ -357,12 +357,25 @@ Rect Station::GetCatchmentRect() const
 
 /**
  * Add nearby industry to station's industries_near list if it accepts cargo.
- * @param ind Industry
+ * For industries that are already on the list update distance if it's closer.
+ * @param ind  Industry
+ * @param tile Tile of the industry to measure distance to.
  */
-void Station::AddIndustryToDeliver(Industry *ind)
+void Station::AddIndustryToDeliver(Industry *ind, TileIndex tile)
 {
-	/* Don't check further if this industry is already in the list */
-	if (this->industries_near.find(ind) != this->industries_near.end()) return;
+	/* Using DistanceMax to get about the same order as with previously used CircularTileSearch. */
+	uint distance = DistanceMax(this->xy, tile);
+
+	/* Don't check further if this industry is already in the list but update the distance if it's closer */
+	auto pos = std::find_if(this->industries_near.begin(), this->industries_near.end(), [&](const IndustryListEntry &e) { return e.industry->index == ind->index; });
+	if (pos != this->industries_near.end()) {
+		if (pos->distance > distance) {
+			auto node = this->industries_near.extract(pos);
+			node.value().distance = distance;
+			this->industries_near.insert(std::move(node));
+		}
+		return;
+	}
 
 	/* Include only industries that can accept cargo */
 	uint cargo_index;
@@ -371,9 +384,21 @@ void Station::AddIndustryToDeliver(Industry *ind)
 	}
 	if (cargo_index >= lengthof(ind->accepts_cargo)) return;
 
-	this->industries_near.insert(ind);
+	this->industries_near.insert(IndustryListEntry{distance, ind});
 }
 
+/**
+ * Remove nearby industry from station's industries_near list.
+ * @param ind  Industry
+ */
+void Station::RemoveIndustryToDeliver(Industry *ind) {
+	auto pos = std::find_if(this->industries_near.begin(), this->industries_near.end(), [&](const IndustryListEntry &e) { return e.industry->index == ind->index; });
+	if (pos != this->industries_near.end()) {
+		this->industries_near.erase(pos);
+	}
+}
+
+
 /**
  * Remove this station from the nearby stations lists of all towns and industries.
  */
@@ -423,11 +448,11 @@ void Station::RecomputeCatchment()
 		}
 		/* 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);
+			st->RemoveIndustryToDeliver(this->industry);
 		}
 		this->industry->stations_near.clear();
 		this->industry->stations_near.insert(this);
-		this->industries_near.insert(this->industry);
+		this->industries_near.insert(IndustryListEntry{0, this->industry});
 		return;
 	}
 
@@ -462,7 +487,7 @@ void Station::RecomputeCatchment()
 			i->stations_near.insert(this);
 
 			/* Add if we can deliver to this industry as well */
-			this->AddIndustryToDeliver(i);
+			this->AddIndustryToDeliver(i, tile);
 		}
 	}
 }

src/station_base.h

@@ -437,11 +437,18 @@ private:
 	}
 };
 
+struct IndustryListEntry {
+	uint distance;
+	Industry *industry;
+
+	bool operator== (const IndustryListEntry &other) const { return this->distance == other.distance && this->industry == other.industry; };
+};
+
 struct IndustryCompare {
-	bool operator() (const Industry *lhs, const Industry *rhs) const;
+	bool operator() (const IndustryListEntry &lhs, const IndustryListEntry &rhs) const;
 };
 
-typedef std::set<Industry *, IndustryCompare> IndustryList;
+typedef std::set<IndustryListEntry, IndustryCompare> IndustryList;
 
 /** Station data structure */
 struct Station FINAL : SpecializedStation<Station, false> {
@@ -500,7 +507,8 @@ public:
 	uint GetCatchmentRadius() const;
 	Rect GetCatchmentRect() const;
 	bool CatchmentCoversTown(TownID t) const;
-	void AddIndustryToDeliver(Industry *ind);
+	void AddIndustryToDeliver(Industry *ind, TileIndex tile);
+	void RemoveIndustryToDeliver(Industry *ind);
 	void RemoveFromAllNearbyLists();
 
 	inline bool TileIsInCatchment(TileIndex tile) const

src/subsidy.cpp

@@ -600,9 +600,9 @@ bool CheckSubsidised(CargoID cargo_type, CompanyID company, SourceType src_type,
 		if (s->cargo_type == cargo_type && s->src_type == src_type && s->src == src && (!s->IsAwarded() || s->awarded == company)) {
 			switch (s->dst_type) {
 				case ST_INDUSTRY:
-					for (Industry *ind : st->industries_near) {
-						if (s->dst == ind->index) {
-							assert(ind->part_of_subsidy & POS_DST);
+					for (const auto &i : st->industries_near) {
+						if (s->dst == i.industry->index) {
+							assert(i.industry->part_of_subsidy & POS_DST);
 							subsidised = true;
 							if (!s->IsAwarded()) s->AwardTo(company);
 						}