(svn r1751) - Feature: New PathFinder (NPF).

	- Supports trains, road vehicles and ships.
	- Uses A* pathfinding (same codebase as the new ai).
	- Currently unlimited search depth, so might perform badly on large maps/networks (especially ships).
	- Will always find a route if there is one.
	- Allows custom penalties for obstacles to be set in openttd.cfg (npf_ values).
	- With NPF enabled, ships can have orders that are very far apart. Be careful, this will break (ships get lost) when the old pathfinder is used again.
- Feature: Disabling 90 degree turns for trains and ships.
	- Requires NPF to be enabled.
	- Ships and trains can no longer make weird 90 degree turns on tile borders.
- Codechange: Removed table/directions.h.
	- table/directions.h contained ugly static tables but was included more than once. The tables, along with a few new ones are in npf.[ch] now. Better suggestions for a location?
- Fix: Binary heap in queue.c did not allocate enough space, resulting in a segfault.
- Codechange: Rewritten FindFirstBit2x64, added KillFirstBit2x64.
- Codechange: Introduced constant INVALID_TILE, to replace the usage of 0 as an invalid tile. Also replaces TILE_WRAPPED.
- Codechange: Moved TileAddWrap() to map.[ch] 
- Add TileIndexDiffCByDir(), TileIndexDiffCByDir(). 
- Codechange: Moved IsTrainStationTile() to station.h
- Add: IsRoadStationTile() and GetRoadStationDir().

1 files changed, 776 insertions, 0 deletions

diff --git a/npf.c b/npf.c
new file mode 100644
index 000000000..430c03ebb
--- /dev/null
+++ b/npf.c
@@ -0,0 +1,776 @@
+#include "stdafx.h"
+#include "ttd.h"
+#include "npf.h"
+#include "aystar.h"
+#include "macros.h"
+#include "pathfind.h"
+#include "station.h"
+#include "tile.h"
+
+AyStar _train_find_station;
+AyStar _train_find_depot;
+AyStar _road_find_station;
+AyStar _road_find_depot;
+AyStar _npf_aystar;
+
+/* Maps a trackdir to the bit that stores its status in the map arrays, in the
+ * direction along with the trackdir */
+const byte _signal_along_trackdir[14] = {
+	0x80, 0x80, 0x80, 0x20, 0x40, 0x10, 0, 0,
+	0x40, 0x40, 0x40, 0x10, 0x80, 0x20
+};
+
+/* Maps a trackdir to the bit that stores its status in the map arrays, in the
+ * direction against the trackdir */
+const byte _signal_against_trackdir[14] = {
+	0x40, 0x40, 0x40, 0x10, 0x80, 0x20, 0, 0,
+	0x80, 0x80, 0x80, 0x20, 0x40, 0x10
+};
+
+/* Maps a trackdir to the trackdirs that can be reached from it (ie, when
+ * entering the next tile */
+const uint16 _trackdir_reaches_trackdirs[14] = {
+0x1009, 0x0016, 0x1009, 0x0016, 0x0520, 0x0016, 0, 0,
+0x0520, 0x2A00, 0x2A00, 0x0520, 0x2A00, 0x1009
+};
+
+/* Maps a trackdir to all trackdirs that make 90 deg turns with it. */
+const uint16 _trackdir_crosses_trackdirs[14] = {
+0x0202, 0x0101, 0x3030, 0x3030, 0x0C0C, 0x0C0C, 0, 0,
+0x0202, 0x0101, 0x3030, 0x3030, 0x0C0C, 0x0C0C
+};
+
+/* Maps a track to all tracks that make 90 deg turns with it. */
+const byte _track_crosses_tracks[6] = {
+	0x2, /* Track 1 -> Track 2 */
+	0x1, /* Track 2 -> Track 1 */
+	0x30, /* Upper -> Left | Right */
+	0x30, /* Lower -> Left | Right */
+	0x0C, /* Left -> Upper | Lower */
+	0x0C, /* Right -> Upper | Lower */
+};
+
+/* Maps a trackdir to the (4-way) direction the tile is exited when following
+ * that trackdir */
+const byte _trackdir_to_exitdir[14] = {
+	0,1,0,1,2,1, 0,0,
+	2,3,3,2,3,0,
+};
+
+const byte _track_exitdir_to_trackdir[6][4] = {
+	{0,    0xff, 8,    0xff},
+	{0xff, 1,    0xff, 9},
+	{2,    0xff, 0xff, 10},
+	{0xff, 3,    11,   0xf},
+	{0xff, 0xff, 4,    12},
+	{13,   5,    0xff, 0xff}
+};
+
+const byte _track_direction_to_trackdir[6][8] = {
+	{0xff, 0,    0xff, 0xff, 0xff, 8,    0xff, 0xff},
+	{0xff, 0xff, 0xff, 1,    0xff, 0xff, 0xff, 9},
+	{0xff, 0xff, 2,    0xff, 0xff, 0xff, 10,   0xff},
+	{0xff, 0xff, 3,    0xff, 0xff, 0xff, 11,   0xff},
+	{12,   0xff, 0xff, 0xff, 4,    0xff, 0xff, 0xff},
+	{13,   0xff, 0xff, 0xff, 5,    0xff, 0xff, 0xff}
+};
+
+const byte _dir_to_diag_trackdir[4] = {
+	0, 1, 8, 9,
+};
+
+const byte _reverse_dir[4] = {
+	2, 3, 0, 1
+};
+
+const byte _reverse_trackdir[14] = {
+	8, 9, 10, 11, 12, 13, 0xFF, 0xFF,
+	0, 1, 2,  3,  4,  5
+};
+
+/* The cost of each trackdir. A diagonal piece is the full NPF_TILE_LENGTH,
+ * the shorter piece is sqrt(2)/2*NPF_TILE_LENGTH =~ 0.7071
+ */
+#define NPF_STRAIGHT_LENGTH (uint)(NPF_TILE_LENGTH * 0.7071)
+static const uint _trackdir_length[14] = {
+NPF_TILE_LENGTH, NPF_TILE_LENGTH, NPF_STRAIGHT_LENGTH, NPF_STRAIGHT_LENGTH, NPF_STRAIGHT_LENGTH, NPF_STRAIGHT_LENGTH, 0, 0,
+NPF_TILE_LENGTH, NPF_TILE_LENGTH, NPF_STRAIGHT_LENGTH, NPF_STRAIGHT_LENGTH, NPF_STRAIGHT_LENGTH, NPF_STRAIGHT_LENGTH
+};
+
+uint NTPHash(uint key1, uint key2)
+{
+	return PATHFIND_HASH_TILE(key1);
+}
+
+int32 NPFCalcZero(AyStar* as, AyStarNode* current, OpenListNode* parent) {
+	return 0;
+}
+
+/* Calcs the heuristic to the target station (using NPFFindStationOrTileData). After
+ * will save the heuristic into NPFFoundTargetData if it is the smallest until
+ * now. It will then also save AyStarNode.user_data[NPF_TRACKDIR_CHOICE] in
+ * best_trackdir
+ */
+int32 NPFCalcStationOrTileHeuristic(AyStar* as, AyStarNode* current, OpenListNode* parent) {
+	NPFFindStationOrTileData* fstd = (NPFFindStationOrTileData*)as->user_target;
+	NPFFoundTargetData* ftd = (NPFFoundTargetData*)as->user_path;
+	TileIndex from = current->tile;
+	TileIndex to = fstd->dest_coords;
+	uint dist = DistanceManhattan(from, to) * NPF_TILE_LENGTH;
+
+	if (dist < ftd->best_bird_dist) {
+		ftd->best_bird_dist = dist;
+		ftd->best_trackdir = current->user_data[NPF_TRACKDIR_CHOICE];
+	}
+	#ifdef NPF_DEBUG
+	debug("Calculating H for: (%d, %d). Result: %d", TileX(current->tile), TileY(current->tile), dist);
+	#endif
+	return dist;
+}
+
+/* Fills AyStarNode.user_data[NPF_TRACKDIRCHOICE] with the chosen direction to
+ * get here, either getting it from the current choice or from the parent's
+ * choice */
+void NPFFillTrackdirChoice(AyStarNode* current, OpenListNode* parent)
+{
+	if (parent->path.parent == NULL) {
+		byte trackdir = current->direction;
+		/* This is a first order decision, so we'd better save the
+		 * direction we chose */
+		current->user_data[NPF_TRACKDIR_CHOICE] = trackdir;
+		#ifdef NPF_DEBUG
+		debug("Saving trackdir: %#x", trackdir);
+		#endif
+	} else {
+		/* We've already made the decision, so just save our parent's
+		 * decision */
+		current->user_data[NPF_TRACKDIR_CHOICE] = parent->path.node.user_data[NPF_TRACKDIR_CHOICE];
+	}
+
+}
+
+/* Will return the cost of the tunnel. If it is an entry, it will return the
+ * cost of that tile. If the tile is an exit, it will return the tunnel length
+ * including the exit tile. Requires that this is a Tunnel tile */
+uint NPFTunnelCost(AyStarNode* current) {
+	byte exitdir = _trackdir_to_exitdir[current->direction];
+	TileIndex tile = current->tile;
+	if ( (uint)(_map5[tile] & 3) == _reverse_dir[exitdir]) {
+		/* We just popped out if this tunnel, since were
+		 * facing the tunnel exit */
+		FindLengthOfTunnelResult flotr;
+		flotr = FindLengthOfTunnel(tile, _reverse_dir[exitdir]);
+		return flotr.length * NPF_TILE_LENGTH;
+		//TODO: Penalty for tunnels?
+	} else {
+		/* We are entering the tunnel, the enter tile is just a
+		 * straight track */
+		return NPF_TILE_LENGTH;
+	}
+}
+
+uint NPFSlopeCost(AyStarNode* current) {
+	TileIndex next = current->tile + TileOffsByDir(_trackdir_to_exitdir[current->direction]);
+	if (GetTileZ(next) > GetTileZ(current->tile)) {
+		/* Slope up */
+		return _patches.npf_rail_slope_penalty;
+	}
+	return 0;
+	/* Should we give a bonus for slope down? Probably not, we
+	 * could just substract that bonus from the penalty, because
+	 * there is only one level of steepness... */
+}
+
+void NPFMarkTile(TileIndex tile) {
+	switch(GetTileType(tile)) {
+		case MP_RAILWAY:
+		case MP_STREET:
+			/* DEBUG: mark visited tiles by mowing the grass under them
+			 * ;-) */
+			_map2[tile] &= ~15;
+			MarkTileDirtyByTile(tile);
+			break;
+		default:
+			break;
+	}
+}
+
+int32 NPFWaterPathCost(AyStar* as, AyStarNode* current, OpenListNode* parent) {
+	//TileIndex tile = current->tile;
+	int32 cost = 0;
+	byte trackdir = current->direction;
+
+	cost = _trackdir_length[trackdir]; /* Should be different for diagonal tracks */
+
+	/* TODO Penalties? */
+
+	return cost;
+}
+
+/* Determine the cost of this node, for road tracks */
+int32 NPFRoadPathCost(AyStar* as, AyStarNode* current, OpenListNode* parent) {
+	TileIndex tile = current->tile;
+	int32 cost = 0;
+	/* Determine base length */
+	switch (GetTileType(tile)) {
+		case MP_TUNNELBRIDGE:
+			if ((_map5[tile] & 0xF0)==0) {
+				cost = NPFTunnelCost(current);
+				break;
+			}
+			/* Fall through if above if is false, it is a bridge
+			 * then. We treat that as ordinary rail */
+		case MP_STREET:
+			cost = NPF_TILE_LENGTH;
+			break;
+		default:
+			break;
+	}
+
+	/* Determine extra costs */
+
+	/* Check for slope */
+	cost += NPFSlopeCost(current);
+
+	/* Check for turns */
+	//TODO
+
+	#ifdef NPF_MARKROUTE
+	NPFMarkTile(tile);
+	#endif
+	#ifdef NPF_DEBUG
+	debug("Calculating G for: (%d, %d). Result: %d", TileX(current->tile), TileY(current->tile), cost);
+	#endif
+	return cost;
+}
+
+
+/* Determine the cost of this node, for railway tracks */
+int32 NPFRailPathCost(AyStar* as, AyStarNode* current, OpenListNode* parent) {
+	TileIndex tile = current->tile;
+	byte trackdir = current->direction;
+	int32 cost = 0;
+	/* Determine base length */
+	switch (GetTileType(tile)) {
+		case MP_TUNNELBRIDGE:
+			if ((_map5[tile] & 0xF0)==0) {
+				cost = NPFTunnelCost(current);
+				break;
+			}
+			/* Fall through if above if is false, it is a bridge
+			 * then. We treat that as ordinary rail */
+		case MP_RAILWAY:
+			cost = _trackdir_length[trackdir]; /* Should be different for diagonal tracks */
+			break;
+		case MP_STREET: /* Railway crossing */
+			cost = NPF_TILE_LENGTH;
+			break;
+		default:
+			break;
+	}
+
+	/* Determine extra costs */
+
+	/* Ordinary track with signals */
+	if (IsTileType(tile, MP_RAILWAY) && (_map5[tile] & 0xC0) == 0x40) {
+		if ((_map2[tile] & _signal_along_trackdir[trackdir]) == 0) {
+			/* Signal facing us is red */
+			if (!(current->user_data[NPF_NODE_FLAGS] & NPF_FLAG_SEEN_SIGNAL)) {
+				/* Penalize the first signal we
+				 * encounter, if it is red */
+				cost += _patches.npf_rail_firstred_penalty;
+			}
+		}
+		current->user_data[NPF_NODE_FLAGS] |= NPF_FLAG_SEEN_SIGNAL;
+	}
+
+	/* Check for slope */
+	cost += NPFSlopeCost(current);
+
+	/* Check for turns */
+	//TODO
+
+	/* Check for occupied track */
+	//TODO
+
+	/* Check for station tiles */
+	if (IsTileType(tile, MP_STATION)) {
+		/* We give a station tile a penalty. Logically we would only
+		 * want to give station tiles that are not our destination
+		 * this penalty. This would discourage trains to drive through
+		 * busy stations. But, we can just give any station tile a
+		 * penalty, because every possible route will get this penalty
+		 * exactly once, on its end tile (if it's a station) and it
+		 * will therefore not make a difference. */
+		cost += _patches.npf_rail_station_penalty;
+	}
+
+	#ifdef NPF_MARKROUTE
+	NPFMarkTile(tile);
+	#endif
+	#ifdef NPF_DEBUG
+	debug("Calculating G for: (%d, %d). Result: %d", TileX(current->tile), TileY(current->tile), cost);
+	#endif
+	return cost;
+}
+
+/* Will find any depot */
+int32 NPFFindDepot(AyStar* as, OpenListNode *current) {
+	TileIndex tile = current->path.node.tile;
+	bool isDepot;
+	switch(GetTileType(tile)) {
+		case MP_RAILWAY:
+			/* Check if this is a rail depot */
+			isDepot = IsTrainDepotTile(tile);
+			break;
+		case MP_STREET:
+			/* Check if this is a road depot */
+			isDepot = IsRoadDepotTile(tile);
+			break;
+		case MP_WATER:
+			isDepot = IsShipDepotTile(tile);
+			break;
+		default:
+			isDepot = false;
+			break;
+	}
+	if (isDepot)
+		return AYSTAR_FOUND_END_NODE;
+	else
+		return AYSTAR_DONE;
+}
+
+/* Will find a station identified using the NPFFindStationOrTileData */
+int32 NPFFindStationOrTile(AyStar* as, OpenListNode *current) {
+	/* If GetNeighbours said we could get here, we assume the station type
+	 * is correct */
+	NPFFindStationOrTileData* fstd = (NPFFindStationOrTileData*)as->user_target;
+	TileIndex tile = current->path.node.tile;
+	if (	(fstd->station_index == -1 && tile == fstd->dest_coords) || /* We've found the tile, or */
+		(IsTileType(tile, MP_STATION) && _map2[tile] == fstd->station_index) /* the station */
+	   )
+			return AYSTAR_FOUND_END_NODE;
+	else
+		return AYSTAR_DONE;
+}
+
+/* To be called when current contains the (shortest route to) the target node.
+ * Will fill the contents of the NPFFoundTargetData using
+ * AyStarNode[NPF_TRACKDIR_CHOICE].
+ */
+void NPFSaveTargetData(AyStar* as, OpenListNode* current) {
+	NPFFoundTargetData* ftd = (NPFFoundTargetData*)as->user_path;
+	ftd->best_trackdir = current->path.node.user_data[NPF_TRACKDIR_CHOICE];
+	ftd->best_path_dist = current->g;
+	ftd->best_bird_dist = 0;
+	ftd->node = current->path.node;
+}
+
+/* Will just follow the results of GetTileTrackStatus concerning where we can
+ * go and where not. Uses AyStar.user_data[NPF_TYPE] as the transport type and
+ * an argument to GetTileTrackStatus. Will skip tunnels, meaning that the
+ * entry and exit are neighbours. Will fill AyStarNode.user_data[NPF_TRACKDIR_CHOICE] with an
+ * appropriate value, and copy AyStarNode.user_data[NPF_NODE_FLAGS] from the
+ * parent */
+void NPFFollowTrack(AyStar* aystar, OpenListNode* current) {
+	byte src_trackdir = current->path.node.direction;
+	TileIndex src_tile = current->path.node.tile;
+	byte src_exitdir = _trackdir_to_exitdir[src_trackdir];
+	FindLengthOfTunnelResult flotr;
+	TileIndex dst_tile;
+	int i = 0;
+	uint trackdirs, ts;
+	TransportType type = aystar->user_data[NPF_TYPE];
+	/* Initialize to 0, so we can jump out (return) somewhere an have no neighbours */
+	aystar->num_neighbours = 0;
+	#ifdef NPF_DEBUG
+	debug("Expanding: (%d, %d, %d) [%d]", TileX(src_tile), TileY(src_tile), src_trackdir, src_tile);
+	#endif
+
+	/* Find dest tile */
+	if (IsTileType(src_tile, MP_TUNNELBRIDGE) && (_map5[src_tile] & 0xF0)==0 && (_map5[src_tile] & 3) == src_exitdir) {
+		/* This is a tunnel. We know this tunnel is our type,
+		 * otherwise we wouldn't have got here. It is also facing us,
+		 * so we should skip it's body */
+		flotr = FindLengthOfTunnel(src_tile, src_exitdir);
+		dst_tile = flotr.tile;
+	} else {
+		if (
+			(type == TRANSPORT_ROAD && IsRoadStationTile(src_tile))
+			|| (type == TRANSPORT_ROAD && IsRoadDepotTile(src_tile))
+			|| (type == TRANSPORT_RAIL && IsTrainDepotTile(src_tile))
+			){
+			/* This is a road station or a train or road depot. We can enter and exit
+			 * those from one side only. Trackdirs don't support that (yet), so we'll
+			 * do this here. */
+
+			byte exitdir;
+			/* Find out the exit direction first */
+			if (IsRoadStationTile(src_tile))
+				exitdir = GetRoadStationDir(src_tile);
+			else /* Train or road depot. Direction is stored the same for both, in map5 */
+				exitdir = _map5[src_tile] & 3; /* Extract the direction from the map */
+
+			/* Let's see if were headed the right way */
+			if (src_trackdir != _dir_to_diag_trackdir[exitdir])
+				/* Not going out of the station/depot through the exit, but the back. No
+				 * neighbours then. */
+				return;
+		}
+		/* This a normal tile, a bridge, a tunnel exit, etc. */
+		dst_tile = AddTileIndexDiffCWrap(src_tile, TileIndexDiffCByDir(_trackdir_to_exitdir[src_trackdir]));
+		if (dst_tile == INVALID_TILE) {
+			/* We reached the border of the map */
+			/* TODO Nicer control flow for this */
+			return;
+		}
+	}
+
+	// TODO: check correct rail type (mono, maglev, etc)
+	// TODO: check tile owner
+
+	/* Determine available tracks */
+	if (type == TRANSPORT_ROAD && (IsRoadStationTile(dst_tile) || IsRoadDepotTile(dst_tile))){
+		byte exitdir;
+		/* Road stations and depots return 0 on GTTS, so we have to do this by hand... */
+			if (IsRoadStationTile(dst_tile))
+				exitdir = GetRoadStationDir(dst_tile);
+			else /* Road depot */
+				exitdir = _map5[dst_tile] & 3; /* Extract the direction from the map */
+			ts = (1 << _dir_to_diag_trackdir[exitdir]) |
+					(1 << _dir_to_diag_trackdir[_reverse_dir[exitdir]]);
+					/* Find the trackdirs that are available for a station with this orientation. They are in both directions */
+	} else {
+		ts = GetTileTrackStatus(dst_tile, type);
+	}
+	trackdirs = ts & 0x3F3F; /* Filter out signal status and the unused bits */
+
+	#ifdef NPF_DEBUG
+	debug("Next node: (%d, %d) [%d], possible trackdirs: %#x", TileX(dst_tile), TileY(dst_tile), dst_tile, trackdirs);
+	#endif
+	/* Select only trackdirs we can reach from our current trackdir */
+	trackdirs &= _trackdir_reaches_trackdirs[src_trackdir];
+	if (_patches.forbid_90_deg && (type == TRANSPORT_RAIL || type == TRANSPORT_WATER)) /* Filter out trackdirs that would make 90 deg turns for trains */
+		trackdirs &= ~_trackdir_crosses_trackdirs[src_trackdir];
+	#ifdef NPF_DEBUG
+	debug("After filtering: (%d, %d), possible trackdirs: %#x", TileX(dst_tile), TileY(dst_tile), trackdirs);
+	#endif
+
+	/* Enumerate possible track */
+	while (trackdirs != 0) {
+		byte dst_trackdir;
+		dst_trackdir =  FindFirstBit2x64(trackdirs);
+		trackdirs = KillFirstBit2x64(trackdirs);
+		#ifdef NPF_DEBUG
+		debug("Expanded into trackdir: %d, remaining trackdirs: %#x", dst_trackdir, trackdirs);
+		#endif
+
+		/* Check for oneway signal against us */
+		if (IsTileType(dst_tile, MP_RAILWAY) && (_map5[dst_tile]&0xC0) == 0x40) {
+			// the tile has a signal
+			byte signal_present = _map3_lo[dst_tile];
+			if (!(signal_present & _signal_along_trackdir[dst_trackdir])) {
+				// if one way signal not pointing towards us, stop going in this direction.
+				if (signal_present & _signal_against_trackdir[dst_trackdir])
+					break;
+			}
+		}
+		{
+			/* We've found ourselves a neighbour :-) */
+			AyStarNode* neighbour = &aystar->neighbours[i];
+			neighbour->tile = dst_tile;
+			neighbour->direction = dst_trackdir;
+			/* Save user data */
+			neighbour->user_data[NPF_NODE_FLAGS] = current->path.node.user_data[NPF_NODE_FLAGS];
+			NPFFillTrackdirChoice(neighbour, current);
+		}
+		i++;
+	}
+	aystar->num_neighbours = i;
+}
+
+/*
+ * Plan a route to the specified target (which is checked by target_proc),
+ * from start1 and if not NULL, from start2 as well. The type of transport we
+ * are checking is in type.
+ * When we are looking for one specific target (optionally multiple tiles), we
+ * should use a good heuristic to perform aystar search. When we search for
+ * multiple targets that are spread around, we should perform a breadth first
+ * search by specifiying CalcZero as our heuristic.
+ */
+NPFFoundTargetData NPFRouteInternal(AyStarNode* start1, AyStarNode* start2, NPFFindStationOrTileData* target, AyStar_EndNodeCheck target_proc, AyStar_CalculateH heuristic_proc, TransportType type) {
+	int r;
+	NPFFoundTargetData result;
+
+	/* Initialize procs */
+	_npf_aystar.CalculateH = heuristic_proc;
+	_npf_aystar.EndNodeCheck = target_proc;
+	_npf_aystar.FoundEndNode = NPFSaveTargetData;
+	_npf_aystar.GetNeighbours = NPFFollowTrack;
+	if (type == TRANSPORT_RAIL)
+		_npf_aystar.CalculateG = NPFRailPathCost;
+	else if (type == TRANSPORT_ROAD)
+		_npf_aystar.CalculateG = NPFRoadPathCost;
+	else if (type == TRANSPORT_WATER)
+		_npf_aystar.CalculateG = NPFWaterPathCost;
+	else
+		assert(0);
+
+	/* Initialize Start Node(s) */
+	start1->user_data[NPF_TRACKDIR_CHOICE] = 0xff;
+	start1->user_data[NPF_NODE_FLAGS] = 0;
+	_npf_aystar.addstart(&_npf_aystar, start1);
+	if (start2) {
+		start2->user_data[NPF_TRACKDIR_CHOICE] = 0xff;
+		start2->user_data[NPF_NODE_FLAGS] = NPF_FLAG_REVERSE;
+		_npf_aystar.addstart(&_npf_aystar, start2);
+	}
+
+	/* Initialize result */
+	result.best_bird_dist = (uint)-1;
+	result.best_path_dist = (uint)-1;
+	result.best_trackdir = 0xff;
+	_npf_aystar.user_path = &result;
+
+	/* Initialize target */
+	_npf_aystar.user_target = target;
+
+	/* Initialize user_data */
+	_npf_aystar.user_data[NPF_TYPE] = type;
+
+	/* GO! */
+	r = AyStarMain_Main(&_npf_aystar);
+	assert(r != AYSTAR_STILL_BUSY);
+
+	if (result.best_bird_dist != 0) {
+		if (target) {
+			DEBUG(misc, 1) ("NPF: Could not find route to 0x%x from 0x%x.", target->dest_coords, start1->tile);
+		} else {
+			/* Assumption: target == NULL, so we are looking for a depot */
+			DEBUG(misc, 1) ("NPF: Could not find route to a depot from 0x%x.", start1->tile);
+		}
+
+	}
+	return result;
+}
+
+NPFFoundTargetData NPFRouteToStationOrTileTwoWay(TileIndex tile1, byte trackdir1, TileIndex tile2, byte trackdir2, NPFFindStationOrTileData* target, TransportType type) {
+	AyStarNode start1;
+	AyStarNode start2;
+
+	start1.tile = tile1;
+	start2.tile = tile2;
+	start1.direction = trackdir1;
+	start2.direction = trackdir2;
+
+	return NPFRouteInternal(&start1, &start2, target, NPFFindStationOrTile, NPFCalcStationOrTileHeuristic, type);
+}
+
+NPFFoundTargetData NPFRouteToStationOrTile(TileIndex tile, byte trackdir, NPFFindStationOrTileData* target, TransportType type) {
+	AyStarNode start;
+
+	assert(tile != 0);
+
+	start.tile = tile;
+	start.direction = trackdir;
+	/* We set this in case the target is also the start tile, we will just
+	 * return a not found then */
+	start.user_data[NPF_TRACKDIR_CHOICE] = 0xff;
+
+	return NPFRouteInternal(&start, NULL, target, NPFFindStationOrTile, NPFCalcStationOrTileHeuristic, type);
+}
+
+NPFFoundTargetData NPFRouteToDepotBreadthFirst(TileIndex tile, byte trackdir, TransportType type) {
+	AyStarNode start;
+
+	start.tile = tile;
+	start.direction = trackdir;
+	/* We set this in case the target is also the start tile, we will just
+	 * return a not found then */
+	start.user_data[NPF_TRACKDIR_CHOICE] = 0xff;
+
+	/* perform a breadth first search. Target is NULL,
+	 * since we are just looking for any depot...*/
+	return NPFRouteInternal(&start, NULL, NULL, NPFFindDepot, NPFCalcZero, type);
+}
+
+NPFFoundTargetData NPFRouteToDepotTrialError(TileIndex tile, byte trackdir, TransportType type) {
+	/* Okay, what we're gonna do. First, we look at all depots, calculate
+	 * the manhatten distance to get to each depot. We then sort them by
+	 * distance. We start by trying to plan a route to the closest, then
+	 * the next closest, etc. We stop when the best route we have found so
+	 * far, is shorter than the manhattan distance. This will obviously
+	 * always find the closest depot. It will probably be most efficient
+	 * for ships, since the heuristic will not be to far off then. I hope.
+	 */
+	Queue depots;
+	uint i;
+	TileType tiletype = 0;
+	int r;
+	NPFFoundTargetData best_result;
+	NPFFoundTargetData result;
+	NPFFindStationOrTileData target;
+	AyStarNode start;
+	Depot* current;
+
+
+	/* This is a little ugly, but it works :-S */
+	if (type == TRANSPORT_ROAD)
+		tiletype = MP_STREET;
+	else if (type == TRANSPORT_RAIL)
+		tiletype = MP_RAILWAY;
+	else if (type == TRANSPORT_WATER)
+		tiletype = MP_WATER;
+	else
+		assert(0);
+
+	init_InsSort(&depots);
+	/* Okay, let's find all depots that we can use first */
+	for (i=0;i<lengthof(_depots);i++) {
+		int depot_tile = _depots[i].xy;
+		if (IsTileType(depot_tile, tiletype))
+			depots.push(&depots, &_depots[i], DistanceManhattan(tile, depot_tile));
+
+	}
+
+	/* Now, let's initialise the aystar */
+
+	/* Initialize procs */
+	_npf_aystar.CalculateH = NPFCalcStationOrTileHeuristic;
+	_npf_aystar.EndNodeCheck = NPFFindStationOrTile;
+	_npf_aystar.FoundEndNode = NPFSaveTargetData;
+	_npf_aystar.GetNeighbours = NPFFollowTrack;
+	if (type == TRANSPORT_RAIL)
+		_npf_aystar.CalculateG = NPFRailPathCost;
+	else if (type == TRANSPORT_ROAD)
+		_npf_aystar.CalculateG = NPFRoadPathCost;
+	else if (type == TRANSPORT_WATER)
+		_npf_aystar.CalculateG = NPFWaterPathCost;
+	else
+		assert(0);
+
+	/* Initialize target */
+	target.station_index = -1; /* We will initialize dest_coords inside the loop below */
+	_npf_aystar.user_target = &target;
+
+	/* Initialize user_data */
+	_npf_aystar.user_data[NPF_TYPE] = type;
+
+	/* Initialize Start Node */
+	start.tile = tile;
+	start.direction = trackdir; /* We will initialize user_data inside the loop below */
+
+	/* Initialize Result */
+	_npf_aystar.user_path = &result;
+	best_result.best_path_dist = (uint)-1;
+
+	/* Just iterate the depots in order of increasing distance */
+	while ((current = depots.pop(&depots))) {
+		/* Check to see if we already have a path shorter than this
+		 * depot's manhattan distance. Hack: We call DistanceManhattan
+		 * again, we should probably modify the queue to give us that
+		 * value... */
+		if ( DistanceManhattan(tile, current->xy * NPF_TILE_LENGTH) > best_result.best_path_dist)
+			break;
+
+		/* Initialize Start Node */
+		/* We set this in case the target is also the start tile, we will just
+		 * return a not found then */
+		start.user_data[NPF_TRACKDIR_CHOICE] = 0xff;
+		start.user_data[NPF_NODE_FLAGS] = 0;
+		_npf_aystar.addstart(&_npf_aystar, &start);
+
+		/* Initialize result */
+		result.best_bird_dist = (uint)-1;
+		result.best_path_dist = (uint)-1;
+		result.best_trackdir = 0xff;
+
+		/* Initialize target */
+		target.dest_coords = current->xy;
+
+		/* GO! */
+		r = AyStarMain_Main(&_npf_aystar);
+		assert(r != AYSTAR_STILL_BUSY);
+
+		/* This depot is closer */
+		if (result.best_path_dist < best_result.best_path_dist)
+			best_result = result;
+	}
+	if (result.best_bird_dist != 0) {
+		DEBUG(misc, 1) ("NPF: Could not find route to any depot from 0x%x.", tile);
+	}
+	return best_result;
+}
+
+void InitializeNPF(void)
+{
+		init_AyStar(&_npf_aystar, NTPHash, 1024);
+		_npf_aystar.loops_per_tick = 0;
+		_npf_aystar.max_path_cost = 0;
+		_npf_aystar.max_search_nodes = 0;
+		/*
+		init_AyStar(&_train_find_station, NTPHash, 1024);
+		init_AyStar(&_train_find_depot, NTPHash, 1024);
+		init_AyStar(&_road_find_station, NTPHash, 1024);
+		init_AyStar(&_road_find_depot, NTPHash, 1024);
+
+		_train_find_station.loops_per_tick = 0;
+		_train_find_depot.loops_per_tick = 0;
+		_road_find_station.loops_per_tick = 0;
+		_road_find_depot.loops_per_tick = 0;
+
+		_train_find_station.max_path_cost = 0;
+		_train_find_depot.max_path_cost = 0;
+		_road_find_station.max_path_cost = 0;
+		_road_find_depot.max_path_cost = 0;
+
+		_train_find_station.max_search_nodes = 0;
+		_train_find_depot.max_search_nodes = 0;
+		_road_find_station.max_search_nodes = 0;
+		_road_find_depot.max_search_nodes = 0;
+
+		_train_find_station.CalculateG = NPFRailPathCost;
+		_train_find_depot.CalculateG = NPFRailPathCost;
+		_road_find_station.CalculateG = NPFRoadPathCost;
+		_road_find_depot.CalculateG = NPFRoadPathCost;
+
+		_train_find_station.CalculateH = NPFCalcStationHeuristic;
+		_train_find_depot.CalculateH = NPFCalcStationHeuristic;
+		_road_find_station.CalculateH = NPFCalcStationHeuristic;
+		_road_find_depot.CalculateH = NPFCalcStationHeuristic;
+
+		_train_find_station.EndNodeCheck = NPFFindStationOrTile;
+		_train_find_depot.EndNodeCheck = NPFFindStationOrTile;
+		_road_find_station.EndNodeCheck = NPFFindStationOrTile;
+		_road_find_depot.EndNodeCheck = NPFFindStationOrTile;
+
+		_train_find_station.FoundEndNode = NPFSaveTargetData;
+		_train_find_depot.FoundEndNode = NPFSaveTargetData;
+		_road_find_station.FoundEndNode = NPFSaveTargetData;
+		_road_find_depot.FoundEndNode = NPFSaveTargetData;
+
+		_train_find_station.GetNeighbours = NPFFollowTrack;
+		_train_find_depot.GetNeighbours = NPFFollowTrack;
+		_road_find_station.GetNeighbours = NPFFollowTrack;
+		_road_find_depot.GetNeighbours = NPFFollowTrack;
+		*/
+}
+
+void NPFFillWithOrderData(NPFFindStationOrTileData* fstd, Vehicle* v) {
+	/* Ships don't really reach their stations, but the tile in front. So don't
+	 * save the station id for ships. For roadvehs we don't store it either,
+	 * because multistop depends on vehicles actually reaching the exact
+	 * dest_tile, not just any stop of that station.
+	 * So only for train orders to stations we fill fstd->station_index, for all
+	 * others only dest_coords */
+	if ((v->current_order.type) == OT_GOTO_STATION && v->type == VEH_Train) {
+		fstd->station_index = v->current_order.station;
+		/* Let's take the center of the station as our target tile for trains */
+		Station* st = GetStation(v->current_order.station);
+		TileIndexDiffC center = {st->trainst_w/2, st->trainst_h/2};
+		fstd->dest_coords = TILE_ADD(st->train_tile, ToTileIndexDiff(center));
+	} else {
+		fstd->dest_coords = v->dest_tile;
+		fstd->station_index = -1;
+	}
+}