(svn r24481) -Feature [FS#5127]: Make the pathfinder decide whether ships shall leave depots towards north or south.

src/pathfinder/npf/npf.cpp

@@ -1178,6 +1178,23 @@ Track NPFShipChooseTrack(const Ship *v, TileIndex tile, DiagDirection enterdir,
 	return TrackdirToTrack(ftd.best_trackdir);
 }
 
+bool NPFShipCheckReverse(const Ship *v)
+{
+	NPFFindStationOrTileData fstd;
+	NPFFoundTargetData ftd;
+
+	NPFFillWithOrderData(&fstd, v);
+
+	Trackdir trackdir = v->GetVehicleTrackdir();
+	Trackdir trackdir_rev = ReverseTrackdir(trackdir);
+	assert(trackdir != INVALID_TRACKDIR);
+	assert(trackdir_rev != INVALID_TRACKDIR);
+
+	ftd = NPFRouteToStationOrTileTwoWay(v->tile, trackdir, false, v->tile, trackdir_rev, false, &fstd, TRANSPORT_WATER, 0, v->owner, INVALID_RAILTYPES);
+	/* If we didn't find anything, just keep on going straight ahead, otherwise take the reverse flag */
+	return ftd.best_bird_dist == 0 && NPFGetFlag(&ftd.node, NPF_FLAG_REVERSE);
+}
+
 /*** Trains ***/
 
 FindDepotData NPFTrainFindNearestDepot(const Train *v, int max_penalty)

src/pathfinder/npf/npf_func.h

@@ -49,6 +49,13 @@ Trackdir NPFRoadVehicleChooseTrack(const RoadVehicle *v, TileIndex tile, DiagDir
  */
 Track NPFShipChooseTrack(const Ship *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks, bool &path_found);
 
+/**
+ * Returns true if it is better to reverse the ship before leaving depot using NPF.
+ * @param v the ship leaving the depot
+ * @return true if reversing is better
+ */
+bool NPFShipCheckReverse(const Ship *v);
+
 /**
  * Used when user sends train to the nearest depot or if train needs servicing using NPF
  * @param v            train that needs to go to some depot