Add game event flag for disaster vehicles

src/disaster_vehicle.cpp

@@ -116,6 +116,12 @@ void DisasterVehicle::UpdateImage()
 	this->UpdateSpriteSeqBound();
 }
 
+DisasterVehicle::DisasterVehicle() :
+		SpecializedVehicleBase()
+{
+	RegisterGameEvents(GEF_DISASTER_VEH);
+}
+
 /**
  * Construct the disaster vehicle.
  * @param x         The X coordinate.
@@ -127,6 +133,8 @@ void DisasterVehicle::UpdateImage()
 DisasterVehicle::DisasterVehicle(int x, int y, Direction direction, DisasterSubType subtype, VehicleID big_ufo_destroyer_target) :
 		SpecializedVehicleBase(), big_ufo_destroyer_target(big_ufo_destroyer_target)
 {
+	RegisterGameEvents(GEF_DISASTER_VEH);
+
 	this->vehstatus = VS_UNCLICKABLE;
 
 	this->x_pos = x;

src/disaster_vehicle.h

@@ -42,7 +42,7 @@ struct DisasterVehicle FINAL : public SpecializedVehicle<DisasterVehicle, VEH_DI
 	byte flags;                         ///< Flags about the state of the vehicle, @see AirVehicleFlags
 
 	/** For use by saveload. */
-	DisasterVehicle() : SpecializedVehicleBase() {}
+	DisasterVehicle();
 	DisasterVehicle(int x, int y, Direction direction, DisasterSubType subtype, VehicleID big_ufo_destroyer_target = VEH_INVALID);
 	/** We want to 'destruct' the right class. */
 	virtual ~DisasterVehicle() {}

src/openttd.cpp

@@ -1734,5 +1734,6 @@ char *DumpGameEventFlags(GameEventFlags events, char *b, const char *last)
 	dump('m', GEF_COMPANY_MERGE);
 	dump('n', GEF_RELOAD_NEWGRF);
 	dump('t', GEF_TBTR_REPLACEMENT);
+	dump('D', GEF_DISASTER_VEH);
 	return b;
 }

src/openttd.h

@@ -92,6 +92,7 @@ enum GameEventFlags : uint32 {
 	GEF_COMPANY_MERGE        = 1 << 1, ///< (m) A company has been bought by another
 	GEF_RELOAD_NEWGRF        = 1 << 2, ///< (n) ReloadNewGRFData() has been called
 	GEF_TBTR_REPLACEMENT     = 1 << 3, ///< (t) CMD_TEMPLATE_REPLACE_VEHICLE has been called
+	GEF_DISASTER_VEH         = 1 << 4, ///< (D) A disaster vehicle exists or has been created
 };
 DECLARE_ENUM_AS_BIT_SET(GameEventFlags)