Add: AI/GS IsNoiseLevelIncreaseAllowed.

API addition that may be used to check whether the noise that will be added to the nearest town if an airport would be built at a tile is allowed.

src/script/api/ai/ai_airport.hpp.sq

@@ -50,6 +50,7 @@ void SQAIAirport_Register(Squirrel *engine)
 	SQAIAirport.DefSQStaticMethod(engine, &ScriptAirport::RemoveAirport,                 "RemoveAirport",                 2, ".i");
 	SQAIAirport.DefSQStaticMethod(engine, &ScriptAirport::GetAirportType,                "GetAirportType",                2, ".i");
 	SQAIAirport.DefSQStaticMethod(engine, &ScriptAirport::GetNoiseLevelIncrease,         "GetNoiseLevelIncrease",         3, ".ii");
+	SQAIAirport.DefSQStaticMethod(engine, &ScriptAirport::IsNoiseLevelIncreaseAllowed,   "IsNoiseLevelIncreaseAllowed",   3, ".ii");
 	SQAIAirport.DefSQStaticMethod(engine, &ScriptAirport::GetNearestTown,                "GetNearestTown",                3, ".ii");
 	SQAIAirport.DefSQStaticMethod(engine, &ScriptAirport::GetMaintenanceCostFactor,      "GetMaintenanceCostFactor",      2, ".i");
 	SQAIAirport.DefSQStaticMethod(engine, &ScriptAirport::GetMonthlyMaintenanceCost,     "GetMonthlyMaintenanceCost",     2, ".i");

src/script/api/ai_changelog.hpp

@@ -24,6 +24,7 @@
  * \li AIGroup::SetSecondaryColour
  * \li AIGroup::GetPrimaryColour
  * \li AIGroup::GetSecondaryColour
+ * \li AIAirport::IsNoiseLevelIncreaseAllowed
  *
  * \b 1.9.0
  *

src/script/api/game/game_airport.hpp.sq

@@ -50,6 +50,7 @@ void SQGSAirport_Register(Squirrel *engine)
 	SQGSAirport.DefSQStaticMethod(engine, &ScriptAirport::RemoveAirport,                 "RemoveAirport",                 2, ".i");
 	SQGSAirport.DefSQStaticMethod(engine, &ScriptAirport::GetAirportType,                "GetAirportType",                2, ".i");
 	SQGSAirport.DefSQStaticMethod(engine, &ScriptAirport::GetNoiseLevelIncrease,         "GetNoiseLevelIncrease",         3, ".ii");
+	SQGSAirport.DefSQStaticMethod(engine, &ScriptAirport::IsNoiseLevelIncreaseAllowed,   "IsNoiseLevelIncreaseAllowed",   3, ".ii");
 	SQGSAirport.DefSQStaticMethod(engine, &ScriptAirport::GetNearestTown,                "GetNearestTown",                3, ".ii");
 	SQGSAirport.DefSQStaticMethod(engine, &ScriptAirport::GetMaintenanceCostFactor,      "GetMaintenanceCostFactor",      2, ".i");
 	SQGSAirport.DefSQStaticMethod(engine, &ScriptAirport::GetMonthlyMaintenanceCost,     "GetMonthlyMaintenanceCost",     2, ".i");

src/script/api/game_changelog.hpp

@@ -18,6 +18,9 @@
  * \b 1.10.0
  *
  * This version is not yet released. The following changes are not set in stone yet.
+
+ * API additions:
+ * \li GSAirport::IsNoiseLevelIncreaseAllowed
  *
  * \b 1.9.0
  *

src/script/api/script_airport.cpp

@@ -149,6 +149,34 @@
 	return 1;
 }
 
+/* static */ bool ScriptAirport::IsNoiseLevelIncreaseAllowed(TileIndex tile, AirportType type)
+{
+	extern Town *AirportGetNearestTown(const AirportSpec *as, const TileIterator &it, uint &mindist);
+	extern uint8 GetAirportNoiseLevelForDistance(const AirportSpec *as, uint distance);
+
+	if (!::IsValidTile(tile)) return false;
+	if (!IsAirportInformationAvailable(type)) return false;
+
+	const AirportSpec *as = ::AirportSpec::Get(type);
+	if (!as->IsWithinMapBounds(0, tile)) return false;
+
+	AirportTileTableIterator it(as->table[0], tile);
+	uint dist;
+	Town *t = AirportGetNearestTown(as, it, dist);
+	if (!::Town::IsValidID(t->index)) return false;
+
+	if (_settings_game.economy.station_noise_level) {
+		return GetAirportNoiseLevelForDistance(as, dist) <= t->MaxTownNoise() - t->noise_reached;
+	}
+
+	int num = 0;
+	const Station *st;
+	FOR_ALL_STATIONS(st) {
+		if (st->town == t && (st->facilities & FACIL_AIRPORT) && st->airport.type != AT_OILRIG) num++;
+	}
+	return 1 <= max(0, 2 - num);
+}
+
 /* static */ TownID ScriptAirport::GetNearestTown(TileIndex tile, AirportType type)
 {
 	extern Town *AirportGetNearestTown(const AirportSpec *as, const TileIterator &it, uint &mindist);

src/script/api/script_airport.hpp

@@ -184,6 +184,17 @@ class ScriptAirport : public ScriptObject {
 	 */
 	static int GetNoiseLevelIncrease(TileIndex tile, AirportType type);
 
+	/**
+	 * Checks whether the noise that will be added to the nearest town if an airport would be
+	 *  built at this tile is allowed.
+	 * @param tile The tile to check.
+	 * @param type The AirportType to check.
+	 * @pre IsAirportInformationAvailable(type).
+	 * @return true if and only if the noise level increase added by the airport is allowed.
+	 * @note The noise will be added to the town with TownID GetNearestTown(tile, type).
+	 */
+	static bool IsNoiseLevelIncreaseAllowed(TileIndex tile, AirportType type);
+
 	/**
 	 * Get the TownID of the town whose local authority will influence
 	 *  an airport at some tile.