Import town cargo generation factor patch

Adjust whitespace

http://www.tt-forums.net/viewtopic.php?f=33&t=46399&start=200#p1086221

src/lang/english.txt

@@ -1521,6 +1521,7 @@ STR_CONFIG_SETTING_TOWN_FOUNDING_HELPTEXT                       :Enabling this s
 STR_CONFIG_SETTING_TOWN_FOUNDING_FORBIDDEN                      :Forbidden
 STR_CONFIG_SETTING_TOWN_FOUNDING_ALLOWED                        :Allowed
 STR_CONFIG_SETTING_TOWN_FOUNDING_ALLOWED_CUSTOM_LAYOUT          :Allowed, custom town layout
+STR_CONFIG_SETTING_TOWN_CARGO_FACTOR                            :{LTBLUE}Town cargo generation factor (less < 0 < more): {ORANGE}{STRING2}
 
 STR_CONFIG_SETTING_EXTRA_TREE_PLACEMENT                         :In game placement of trees: {STRING2}
 STR_CONFIG_SETTING_EXTRA_TREE_PLACEMENT_HELPTEXT                :Control random appearance of trees during the game. This might affect industries which rely on tree growth, for example lumber mills

src/settings_gui.cpp

@@ -1556,6 +1556,7 @@ static SettingEntry _settings_economy_towns[] = {
 	SettingEntry("economy.town_growth_rate"),
 	SettingEntry("economy.larger_towns"),
 	SettingEntry("economy.initial_city_size"),
+	SettingEntry("economy.town_cargo_factor"),
 };
 /** Towns sub-page */
 static SettingsPage _settings_economy_towns_page = {_settings_economy_towns, lengthof(_settings_economy_towns)};

src/settings_type.h

@@ -485,6 +485,7 @@ struct EconomySettings {
 	bool   station_noise_level;              ///< build new airports when the town noise level is still within accepted limits
 	uint16 town_noise_population[3];         ///< population to base decision on noise evaluation (@see town_council_tolerance)
 	bool   allow_town_level_crossings;       ///< towns are allowed to build level crossings
+	int8   town_cargo_factor;                ///< power-of-two multiplier for town (passenger, mail) generation. May be negative.
 	bool   infrastructure_maintenance;       ///< enable monthly maintenance fee for owner infrastructure
 };
 

src/table/settings.ini

@@ -712,6 +712,18 @@ str      = STR_CONFIG_SETTING_SHORT_PATH_SATURATION
 strval   = STR_CONFIG_SETTING_PERCENTAGE
 strhelp  = STR_CONFIG_SETTING_SHORT_PATH_SATURATION_HELPTEXT
 
+[SDT_VAR]
+base     = GameSettings
+var      = economy.town_cargo_factor
+type     = SLE_INT8
+from     = 160
+def      = 0
+min      = -16
+max      = +8
+interval = 1
+str      = STR_CONFIG_SETTING_TOWN_CARGO_FACTOR
+strval	 = STR_JUST_INT
+
 ; Vehicles
 
 [SDT_VAR]

src/town_cmd.cpp

@@ -436,6 +436,61 @@ static void MakeTownHouseBigger(TileIndex tile)
 	if (flags & BUILDING_HAS_4_TILES) MakeSingleHouseBigger(TILE_ADDXY(tile, 1, 1));
 }
 
+/**
+ * Generate cargo for a town (house).
+ *
+ * The amount of cargo should be and will be greater than zero.
+ *
+ * @param t current town
+ * @param ct type of cargo to generate, usually CT_PASSENGERS or CT_MAIL
+ * @param amount how many units of cargo
+ * @param stations available stations for this house
+ */
+static void TownGenerateCargo (Town *t, CargoID ct, uint amount, StationFinder &stations)
+{
+	// custom cargo generation factor
+	int cf = _settings_game.economy.town_cargo_factor;
+
+	// when the economy flunctuates, everyone wants to stay at home
+	if (EconomyIsInRecession()) {
+		amount = (amount + 1) >> 1;
+	}
+
+	// apply custom factor?
+	if (cf < 0) {
+		// approx (amount / 2^cf)
+		// adjust with a constant offset of {(2 ^ cf) - 1} (i.e. add cf * 1-bits) before dividing to ensure that it doesn't become zero
+		// this skews the curve a little so that isn't entirely exponential, but will still decrease
+		amount = (amount + ((1 << -cf) - 1)) >> -cf;
+	}
+
+	else if (cf > 0) {
+		// approx (amount * 2^cf)
+		// XXX: overflow?
+		amount = amount << cf;
+	}
+
+	// with the adjustments above, this should never happen
+	assert(amount > 0);
+
+	// calculate for town stats
+	const CargoSpec *cs = CargoSpec::Get(ct);
+	switch (cs->town_effect) {
+		case TE_PASSENGERS:
+			t->supplied[CT_PASSENGERS].new_max += amount;
+			t->supplied[CT_PASSENGERS].new_act += MoveGoodsToStation(CT_PASSENGERS, amount, ST_TOWN, t->index, stations.GetStations());
+			break;
+
+		case TE_MAIL:
+			t->supplied[CT_MAIL].new_max += amount;
+			t->supplied[CT_MAIL].new_act += MoveGoodsToStation(CT_MAIL, amount, ST_TOWN, t->index, stations.GetStations());
+			break;
+
+		default:
+			break;
+	}
+}
+
 /**
  * Tile callback function.
  *
@@ -483,27 +538,20 @@ static void TileLoop_Town(TileIndex tile)
 			uint amt = GB(callback, 0, 8);
 			if (amt == 0) continue;
 
-			uint moved = MoveGoodsToStation(cargo, amt, ST_TOWN, t->index, stations.GetStations());
-
-			const CargoSpec *cs = CargoSpec::Get(cargo);
-			t->supplied[cs->Index()].new_max += amt;
-			t->supplied[cs->Index()].new_act += moved;
+			// XXX: no economy flunctuation for GRF cargos?
+			TownGenerateCargo(t, cargo, amt, stations);
 		}
 	} else {
 		if (GB(r, 0, 8) < hs->population) {
 			uint amt = GB(r, 0, 8) / 8 + 1;
 
-			if (EconomyIsInRecession()) amt = (amt + 1) >> 1;
-			t->supplied[CT_PASSENGERS].new_max += amt;
-			t->supplied[CT_PASSENGERS].new_act += MoveGoodsToStation(CT_PASSENGERS, amt, ST_TOWN, t->index, stations.GetStations());
+			TownGenerateCargo(t, CT_PASSENGERS, amt, stations);
 		}
 
 		if (GB(r, 8, 8) < hs->mail_generation) {
 			uint amt = GB(r, 8, 8) / 8 + 1;
 
-			if (EconomyIsInRecession()) amt = (amt + 1) >> 1;
-			t->supplied[CT_MAIL].new_max += amt;
-			t->supplied[CT_MAIL].new_act += MoveGoodsToStation(CT_MAIL, amt, ST_TOWN, t->index, stations.GetStations());
+			TownGenerateCargo(t, CT_MAIL, amt, stations);
 		}
 	}