Run most "daily" vehicle tasks at a fixed frequency at day lengths >= 8

This includes: running costs, track sharing costs, breakdown checks,
servicing checks, order checks

src/aircraft.h

@@ -111,6 +111,7 @@ struct Aircraft FINAL : public SpecializedVehicle<Aircraft, VEH_AIRCRAFT> {
 
 	bool Tick();
 	void OnNewDay();
+	void OnPeriodic();
 	uint Crash(bool flooded = false);
 	TileIndex GetOrderStationLocation(StationID station);
 	bool FindClosestDepot(TileIndex *location, DestinationID *destination, bool *reverse);

src/aircraft_cmd.cpp

@@ -483,10 +483,16 @@ void Aircraft::OnNewDay()
 
 	if ((++this->day_counter & 7) == 0) DecreaseVehicleValue(this);
 
+	AgeVehicle(this);
+}
+
+void Aircraft::OnPeriodic()
+{
+	if (!this->IsNormalAircraft()) return;
+
 	CheckOrders(this);
 
 	CheckVehicleBreakdown(this);
-	AgeVehicle(this);
 	CheckIfAircraftNeedsService(this);
 
 	if (this->running_ticks == 0) return;

src/roadveh.h

@@ -139,6 +139,7 @@ struct RoadVehicle FINAL : public GroundVehicle<RoadVehicle, VEH_ROAD> {
 	bool IsInDepot() const { return this->state == RVSB_IN_DEPOT; }
 	bool Tick();
 	void OnNewDay();
+	void OnPeriodic();
 	uint Crash(bool flooded = false);
 	Trackdir GetVehicleTrackdir() const;
 	TileIndex GetOrderStationLocation(StationID station);

src/roadveh_cmd.cpp

@@ -2228,6 +2228,12 @@ void RoadVehicle::OnNewDay()
 	if (!this->IsFrontEngine()) return;
 
 	if ((++this->day_counter & 7) == 0) DecreaseVehicleValue(this);
+}
+
+void RoadVehicle::OnPeriodic()
+{
+	if (!this->IsFrontEngine()) return;
+
 	if (this->blocked_ctr == 0) CheckVehicleBreakdown(this);
 
 	CheckIfRoadVehNeedsService(this);

src/ship.h

@@ -55,6 +55,7 @@ struct Ship FINAL : public SpecializedVehicle<Ship, VEH_SHIP> {
 	bool IsInDepot() const { return this->state == TRACK_BIT_DEPOT; }
 	bool Tick();
 	void OnNewDay();
+	void OnPeriodic();
 	Trackdir GetVehicleTrackdir() const;
 	TileIndex GetOrderStationLocation(StationID station);
 	bool FindClosestDepot(TileIndex *location, DestinationID *destination, bool *reverse);

src/ship_cmd.cpp

@@ -248,9 +248,12 @@ void Ship::OnNewDay()
 	if ((++this->day_counter & 7) == 0) {
 		DecreaseVehicleValue(this);
 	}
-
-	CheckVehicleBreakdown(this);
 	AgeVehicle(this);
+}
+
+void Ship::OnPeriodic()
+{
+	CheckVehicleBreakdown(this);
 	CheckIfShipNeedsService(this);
 
 	CheckOrders(this);

src/train.h

@@ -170,6 +170,7 @@ struct Train FINAL : public GroundVehicle<Train, VEH_TRAIN> {
 	bool IsInDepot() const { return this->track == TRACK_BIT_DEPOT; }
 	bool Tick();
 	void OnNewDay();
+	void OnPeriodic();
 	uint Crash(bool flooded = false);
 	Money CalculateCurrentOverallValue() const;
 	Trackdir GetVehicleTrackdir() const;

src/train_cmd.cpp

@@ -6598,7 +6598,10 @@ void Train::OnNewDay()
 	AgeVehicle(this);
 
 	if ((++this->day_counter & 7) == 0) DecreaseVehicleValue(this);
+}
 
+void Train::OnPeriodic()
+{
 	if (this->IsFrontEngine()) {
 		CheckIfTrainNeedsService(this);
 

src/vehicle.cpp

@@ -1245,6 +1245,9 @@ template <typename T>
 void CallVehicleOnNewDay(Vehicle *v)
 {
 	T::From(v)->T::OnNewDay();
+
+	/* Vehicle::OnPeriodic is decoupled from Vehicle::OnNewDay at day lengths >= 8 */
+	if (_settings_game.economy.day_length_factor < 8) T::From(v)->T::OnPeriodic();
 }
 
 /**
@@ -1460,6 +1463,38 @@ void CallVehicleTicks()
 
 	if (_tick_skip_counter == 0) RunVehicleDayProc();
 
+	if (_settings_game.economy.day_length_factor >= 8 && _game_mode == GM_NORMAL) {
+		/*
+		 * Vehicle::OnPeriodic is decoupled from Vehicle::OnNewDay at day lengths >= 8
+		 * Use a fixed interval of 512 ticks (unscaled) instead
+		 */
+
+		Vehicle *v = nullptr;
+		SCOPE_INFO_FMT([&v], "CallVehicleTicks -> OnPeriodic: %s", scope_dumper().VehicleInfo(v));
+		for (size_t i = _scaled_tick_counter & 0x1FF; i < Vehicle::GetPoolSize(); i += 0x200) {
+			v = Vehicle::Get(i);
+			if (v == nullptr) continue;
+
+			/* This is called once per day for each vehicle, but not in the first tick of the day */
+			switch (v->type) {
+				case VEH_TRAIN:
+					Train::From(v)->Train::OnPeriodic();
+					break;
+				case VEH_ROAD:
+					RoadVehicle::From(v)->RoadVehicle::OnPeriodic();
+					break;
+				case VEH_SHIP:
+					Ship::From(v)->Ship::OnPeriodic();
+					break;
+				case VEH_AIRCRAFT:
+					Aircraft::From(v)->Aircraft::OnPeriodic();
+					break;
+				default:
+					break;
+			}
+		}
+	}
+
 	{
 		PerformanceMeasurer framerate(PFE_GL_ECONOMY);
 		Station *si_st = nullptr;

src/vehicle_base.h

@@ -615,6 +615,12 @@ public:
 	 */
 	virtual void OnNewDay() {};
 
+	/**
+	 * Calls the periodic handler of the vehicle
+	 * OnPeriodic is decoupled from OnNewDay at day lengths >= 8
+	 */
+	virtual void OnPeriodic() {};
+
 	/**
 	 * Crash the (whole) vehicle chain.
 	 * @param flooded whether the cause of the crash is flooding or not.