Use separate tile hash for each vehicle type

src/vehicle_func.h

@@ -40,10 +40,79 @@ typedef Vehicle *VehicleFromPosProc(Vehicle *v, void *data);
 
 void VehicleServiceInDepot(Vehicle *v);
 uint CountVehiclesInChain(const Vehicle *v);
-void FindVehicleOnPos(TileIndex tile, void *data, VehicleFromPosProc *proc);
-void FindVehicleOnPosXY(int x, int y, void *data, VehicleFromPosProc *proc);
-bool HasVehicleOnPos(TileIndex tile, void *data, VehicleFromPosProc *proc);
-bool HasVehicleOnPosXY(int x, int y, void *data, VehicleFromPosProc *proc);
+
+/**
+ * Find a vehicle from a specific location. It will call \a proc for ALL vehicles
+ * on the tile and YOU must make SURE that the "best one" is stored in the
+ * data value and is ALWAYS the same regardless of the order of the vehicles
+ * where proc was called on!
+ * When you fail to do this properly you create an almost untraceable DESYNC!
+ * @note The return value of \a proc will be ignored.
+ * @note Use this function when you have the intention that all vehicles
+ *       should be iterated over.
+ * @param tile The location on the map
+ * @param data Arbitrary data passed to \a proc.
+ * @param proc The proc that determines whether a vehicle will be "found".
+ */
+inline void FindVehicleOnPos(TileIndex tile, VehicleType type, void *data, VehicleFromPosProc *proc)
+{
+	extern Vehicle *VehicleFromPos(TileIndex tile, VehicleType type, void *data, VehicleFromPosProc *proc, bool find_first);
+	VehicleFromPos(tile, type, data, proc, false);
+}
+
+/**
+ * Checks whether a vehicle is on a specific location. It will call \a proc for
+ * vehicles until it returns non-nullptr.
+ * @note Use #FindVehicleOnPos when you have the intention that all vehicles
+ *       should be iterated over.
+ * @param tile The location on the map
+ * @param data Arbitrary data passed to \a proc.
+ * @param proc The \a proc that determines whether a vehicle will be "found".
+ * @return True if proc returned non-nullptr.
+ */
+inline bool HasVehicleOnPos(TileIndex tile, VehicleType type, void *data, VehicleFromPosProc *proc)
+{
+	extern Vehicle *VehicleFromPos(TileIndex tile, VehicleType type, void *data, VehicleFromPosProc *proc, bool find_first);
+	return VehicleFromPos(tile, type, data, proc, true) != nullptr;
+}
+
+/**
+ * Find a vehicle from a specific location. It will call proc for ALL vehicles
+ * on the tile and YOU must make SURE that the "best one" is stored in the
+ * data value and is ALWAYS the same regardless of the order of the vehicles
+ * where proc was called on!
+ * When you fail to do this properly you create an almost untraceable DESYNC!
+ * @note The return value of proc will be ignored.
+ * @note Use this when you have the intention that all vehicles
+ *       should be iterated over.
+ * @param x    The X location on the map
+ * @param y    The Y location on the map
+ * @param data Arbitrary data passed to proc
+ * @param proc The proc that determines whether a vehicle will be "found".
+ */
+inline void FindVehicleOnPosXY(int x, int y, VehicleType type, void *data, VehicleFromPosProc *proc)
+{
+	extern Vehicle *VehicleFromPosXY(int x, int y, VehicleType type, void *data, VehicleFromPosProc *proc, bool find_first);
+	VehicleFromPosXY(x, y, type, data, proc, false);
+}
+
+/**
+ * Checks whether a vehicle in on a specific location. It will call proc for
+ * vehicles until it returns non-nullptr.
+ * @note Use FindVehicleOnPosXY when you have the intention that all vehicles
+ *       should be iterated over.
+ * @param x    The X location on the map
+ * @param y    The Y location on the map
+ * @param data Arbitrary data passed to proc
+ * @param proc The proc that determines whether a vehicle will be "found".
+ * @return True if proc returned non-nullptr.
+ */
+inline bool HasVehicleOnPosXY(int x, int y, VehicleType type, void *data, VehicleFromPosProc *proc)
+{
+	extern Vehicle *VehicleFromPosXY(int x, int y, VehicleType type, void *data, VehicleFromPosProc *proc, bool find_first);
+	return VehicleFromPosXY(x, y, type, data, proc, true) != nullptr;
+}
+
 void CallVehicleTicks();
 uint8 CalcPercentVehicleFilled(const Vehicle *v, StringID *colour);
 uint8 CalcPercentVehicleFilledOfCargo(const Vehicle *v, CargoID cargo);