Reduce redundant calls to get current max speed for trains and RVs

Between ShowVisualEffect() and UpdateSpeed()

src/roadveh.h

@@ -150,7 +150,7 @@ struct RoadVehicle FINAL : public GroundVehicle<RoadVehicle, VEH_ROAD> {
 	int GetCurrentMaxSpeed() const;
 	int GetEffectiveMaxSpeed() const;
 	int GetDisplayEffectiveMaxSpeed() const { return this->GetEffectiveMaxSpeed() / 2; }
-	int UpdateSpeed();
+	int UpdateSpeed(int max_speed);
 	void SetDestTile(TileIndex tile);
 
 	inline bool IsRoadVehicleOnLevelCrossing() const

src/roadveh_cmd.cpp

@@ -795,11 +795,11 @@ static void RoadVehArrivesAt(const RoadVehicle *v, Station *st)
  * and subspeed) variables. Furthermore, it returns the distance that
  * the vehicle can drive this tick. #Vehicle::GetAdvanceDistance() determines
  * the distance to drive before moving a step on the map.
+ * @param max_speed maximum speed as from GetCurrentMaxSpeed()
  * @return distance to drive.
  */
-int RoadVehicle::UpdateSpeed()
+int RoadVehicle::UpdateSpeed(int max_speed)
 {
-	int max_speed = this->GetCurrentMaxSpeed();
 	switch (_settings_game.vehicle.roadveh_acceleration_model) {
 		default: NOT_REACHED();
 		case AM_ORIGINAL: {
@@ -2126,10 +2126,14 @@ static bool RoadVehController(RoadVehicle *v)
 
 	if (v->IsInDepot() && RoadVehLeaveDepot(v, true)) return true;
 
-	v->ShowVisualEffect();
+	int j;
+	{
+		int max_speed = v->GetCurrentMaxSpeed();
+		v->ShowVisualEffect(max_speed);
 
 		/* Check how far the vehicle needs to proceed */
-	int j = v->UpdateSpeed();
+		j = v->UpdateSpeed(max_speed);
+	 }
 
 	int adv_spd = v->GetAdvanceDistance();
 	bool blocked = false;

src/ship_cmd.cpp

@@ -885,7 +885,7 @@ static void ShipController(Ship *v)
 
 	if (CheckShipLeaveDepot(v)) return;
 
-	v->ShowVisualEffect();
+	v->ShowVisualEffect(UINT_MAX);
 
 	/* Rotating on spot */
 	if (v->direction != v->rotation) {

src/train.h

@@ -185,15 +185,15 @@ struct Train FINAL : public GroundVehicle<Train, VEH_TRAIN> {
 
 	void ConsistChanged(ConsistChangeFlags allowed_changes);
 
-	int UpdateSpeed();
-
-	void UpdateAcceleration();
-
 	struct MaxSpeedInfo {
 		int strict_max_speed;
 		int advisory_max_speed;
 	};
 
+	int UpdateSpeed(MaxSpeedInfo max_speed_info);
+
+	void UpdateAcceleration();
+
 	bool ConsistNeedsRepair() const;
 
 private:

src/train_cmd.cpp

@@ -4582,17 +4582,16 @@ void Train::MarkDirty()
  * the distance to drive before moving a step on the map.
  * @return distance to drive.
  */
-int Train::UpdateSpeed()
+int Train::UpdateSpeed(MaxSpeedInfo max_speed_info)
 {
 	AccelStatus accel_status = this->GetAccelerationStatus();
-	MaxSpeedInfo max_speed_info = this->GetCurrentMaxSpeedInfoAndUpdate();
 	if (this->lookahead != nullptr && HasBit(this->lookahead->flags, TRLF_APPLY_ADVISORY) && this->cur_speed <= max_speed_info.strict_max_speed) {
 		ClrBit(this->lookahead->flags, TRLF_APPLY_ADVISORY);
 	}
 	switch (_settings_game.vehicle.train_acceleration_model) {
 		default: NOT_REACHED();
 		case AM_ORIGINAL:
-			return this->DoUpdateSpeed({ this->acceleration * (this->GetAccelerationStatus() == AS_BRAKE ? -4 : 2), this->acceleration * -4 }, 0,
+			return this->DoUpdateSpeed({ this->acceleration * (accel_status == AS_BRAKE ? -4 : 2), this->acceleration * -4 }, 0,
 					max_speed_info.strict_max_speed, max_speed_info.advisory_max_speed, this->UsingRealisticBraking());
 
 		case AM_REALISTIC:
@@ -6397,8 +6396,6 @@ static bool TrainLocoHandler(Train *v, bool mode)
 		}
 	}
 
-	if (!mode) v->ShowVisualEffect();
-
 	/* We had no order but have an order now, do look ahead. */
 	if (!valid_order && !v->current_order.IsType(OT_NOTHING)) {
 		CheckNextTrainTile(v);
@@ -6461,7 +6458,13 @@ static bool TrainLocoHandler(Train *v, bool mode)
 		return true;
 	}
 
-	int j = v->UpdateSpeed();
+	int j;
+	{
+		Train::MaxSpeedInfo max_speed_info = v->GetCurrentMaxSpeedInfoAndUpdate();
+
+		if (!mode) v->ShowVisualEffect(std::min(max_speed_info.strict_max_speed, max_speed_info.advisory_max_speed));
+		j = v->UpdateSpeed(max_speed_info);
+	}
 
 	/* we need to invalidate the widget if we are stopping from 'Stopping 0 km/h' to 'Stopped' */
 	if (v->cur_speed == 0 && (v->vehstatus & VS_STOPPED)) {

src/vehicle.cpp

@@ -3865,9 +3865,10 @@ int ReversingDistanceTargetSpeed(const Train *v);
 
 /**
  * Draw visual effects (smoke and/or sparks) for a vehicle chain.
+ * @param max_speed The speed as limited by underground and orders, UINT_MAX if not already known
  * @pre this->IsPrimaryVehicle()
  */
-void Vehicle::ShowVisualEffect() const
+void Vehicle::ShowVisualEffect(uint max_speed) const
 {
 	assert(this->IsPrimaryVehicle());
 	bool sound = false;
@@ -3883,8 +3884,7 @@ void Vehicle::ShowVisualEffect() const
 		return;
 	}
 
-	/* Use the speed as limited by underground and orders. */
-	uint max_speed = this->GetCurrentMaxSpeed();
+	if (max_speed == UINT_MAX) max_speed = this->GetCurrentMaxSpeed();
 
 	if (this->type == VEH_TRAIN) {
 		const Train *t = Train::From(this);

src/vehicle_base.h

@@ -884,7 +884,7 @@ public:
 	CommandCost SendToDepot(DoCommandFlag flags, DepotCommand command, TileIndex specific_depot = 0);
 
 	void UpdateVisualEffect(bool allow_power_change = true);
-	void ShowVisualEffect() const;
+	void ShowVisualEffect(uint max_speed) const;
 
 	/**
 	 * Update the position of the vehicle. This will update the hash that tells