(svn r7759) -Merge: makefile rewrite. This merge features:

 - A proper ./configure, so everything needs to be configured only once, not for every make.
 - Usage of makedepend when available. This greatly reduces the time needed for generating the dependencies.
 - A generator for all project files. There is a single file with sources, which is used to generate Makefiles and the project files for MSVC.
 - Proper support for OSX universal binaries.
 - Object files for non-MSVC compiles are also placed in separate directories, making is faster to switch between debug and release compiles and it does not touch the directory with the source files.
 - Functionality to make a bundle of all needed files for for example a nightly or distribution of a binary with all needed GRFs and language files.

Note: as this merge moves almost all files, it is recommended to make a backup of your working copy before updating your working copy.

1 files changed, 894 insertions, 0 deletions

diff --git a/src/npf.c b/src/npf.c
new file mode 100644
index 000000000..97b9bf367
--- /dev/null
+++ b/src/npf.c
@@ -0,0 +1,894 @@
+/* $Id$ */
+
+#include "stdafx.h"
+#include "openttd.h"
+#include "bridge_map.h"
+#include "debug.h"
+#include "functions.h"
+#include "npf.h"
+#include "aystar.h"
+#include "macros.h"
+#include "pathfind.h"
+#include "station.h"
+#include "station_map.h"
+#include "tile.h"
+#include "depot.h"
+#include "tunnel_map.h"
+#include "network/network.h"
+#include "water_map.h"
+
+static AyStar _npf_aystar;
+
+/* 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 * STRAIGHT_TRACK_LENGTH)
+static const uint _trackdir_length[TRACKDIR_END] = {
+	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
+};
+
+/**
+ * Calculates the minimum distance traveled to get from t0 to t1 when only
+ * using tracks (ie, only making 45 degree turns). Returns the distance in the
+ * NPF scale, ie the number of full tiles multiplied by NPF_TILE_LENGTH to
+ * prevent rounding.
+ */
+static uint NPFDistanceTrack(TileIndex t0, TileIndex t1)
+{
+	const uint dx = abs(TileX(t0) - TileX(t1));
+	const uint dy = abs(TileY(t0) - TileY(t1));
+
+	const uint straightTracks = 2 * min(dx, dy); /* The number of straight (not full length) tracks */
+	/* OPTIMISATION:
+	 * Original: diagTracks = max(dx, dy) - min(dx,dy);
+	 * Proof:
+	 * (dx+dy) - straightTracks  == (min + max) - straightTracks = min + max - 2 * min = max - min */
+	const uint diagTracks = dx + dy - straightTracks; /* The number of diagonal (full tile length) tracks. */
+
+	/* Don't factor out NPF_TILE_LENGTH below, this will round values and lose
+	 * precision */
+	return diagTracks * NPF_TILE_LENGTH + straightTracks * NPF_TILE_LENGTH * STRAIGHT_TRACK_LENGTH;
+}
+
+
+#if 0
+static uint NTPHash(uint key1, uint key2)
+{
+	/* This function uses the old hash, which is fixed on 10 bits (1024 buckets) */
+	return PATHFIND_HASH_TILE(key1);
+}
+#endif
+
+/**
+ * Calculates a hash value for use in the NPF.
+ * @param key1 The TileIndex of the tile to hash
+ * @param key2 The Trackdir of the track on the tile.
+ *
+ * @todo Think of a better hash.
+ */
+static uint NPFHash(uint key1, uint key2)
+{
+	/* TODO: think of a better hash? */
+	uint part1 = TileX(key1) & NPF_HASH_HALFMASK;
+	uint part2 = TileY(key1) & NPF_HASH_HALFMASK;
+
+	assert(IsValidTrackdir(key2));
+	assert(IsValidTile(key1));
+	return ((part1 << NPF_HASH_HALFBITS | part2) + (NPF_HASH_SIZE * key2 / TRACKDIR_END)) % NPF_HASH_SIZE;
+}
+
+static int32 NPFCalcZero(AyStar* as, AyStarNode* current, OpenListNode* parent)
+{
+	return 0;
+}
+
+/* Calcs the tile of given station that is closest to a given tile
+ * for this we assume the station is a rectangle,
+ * as defined by its top tile (st->train_tile) and its width/height (st->trainst_w, st->trainst_h)
+ */
+static TileIndex CalcClosestStationTile(StationID station, TileIndex tile)
+{
+	const Station* st = GetStation(station);
+
+	uint minx = TileX(st->train_tile);  // topmost corner of station
+	uint miny = TileY(st->train_tile);
+	uint maxx = minx + st->trainst_w - 1; // lowermost corner of station
+	uint maxy = miny + st->trainst_h - 1;
+	uint x;
+	uint y;
+
+	// we are going the aim for the x coordinate of the closest corner
+	// but if we are between those coordinates, we will aim for our own x coordinate
+	x = clamp(TileX(tile), minx, maxx);
+
+	// same for y coordinate, see above comment
+	y = clamp(TileY(tile), miny, maxy);
+
+	// return the tile of our target coordinates
+	return TileXY(x, y);
+}
+
+/* Calcs the heuristic to the target station or tile. For train stations, it
+ * takes into account the direction of approach.
+ */
+static 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;
+
+	// for train-stations, we are going to aim for the closest station tile
+	if (as->user_data[NPF_TYPE] == TRANSPORT_RAIL && fstd->station_index != INVALID_STATION)
+		to = CalcClosestStationTile(fstd->station_index, from);
+
+	if (as->user_data[NPF_TYPE] == TRANSPORT_ROAD) {
+		/* Since roads only have diagonal pieces, we use manhattan distance here */
+		dist = DistanceManhattan(from, to) * NPF_TILE_LENGTH;
+	} else {
+		/* Ships and trains can also go diagonal, so the minimum distance is shorter */
+		dist = NPFDistanceTrack(from, to);
+	}
+
+	DEBUG(npf, 4, "Calculating H for: (%d, %d). Result: %d", TileX(current->tile), TileY(current->tile), dist);
+
+	if (dist < ftd->best_bird_dist) {
+		ftd->best_bird_dist = dist;
+		ftd->best_trackdir = current->user_data[NPF_TRACKDIR_CHOICE];
+	}
+	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 */
+static void NPFFillTrackdirChoice(AyStarNode* current, OpenListNode* parent)
+{
+	if (parent->path.parent == NULL) {
+		Trackdir trackdir = (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;
+		DEBUG(npf, 6, "Saving trackdir: 0x%X", trackdir);
+	} 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 */
+static uint NPFTunnelCost(AyStarNode* current)
+{
+	DiagDirection exitdir = TrackdirToExitdir((Trackdir)current->direction);
+	TileIndex tile = current->tile;
+	if (GetTunnelDirection(tile) == ReverseDiagDir(exitdir)) {
+		/* We just popped out if this tunnel, since were
+		 * facing the tunnel exit */
+		FindLengthOfTunnelResult flotr;
+		flotr = FindLengthOfTunnel(tile, ReverseDiagDir(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;
+	}
+}
+
+static inline uint NPFBridgeCost(AyStarNode *current)
+{
+	return NPF_TILE_LENGTH * GetBridgeLength(current->tile, GetOtherBridgeEnd(current->tile));
+}
+
+static uint NPFSlopeCost(AyStarNode* current)
+{
+	TileIndex next = current->tile + TileOffsByDiagDir(TrackdirToExitdir(current->direction));
+	int x,y;
+	int8 z1,z2;
+
+	x = TileX(current->tile) * TILE_SIZE;
+	y = TileY(current->tile) * TILE_SIZE;
+	/* get the height of the center of the current tile */
+	z1 = GetSlopeZ(x + TILE_SIZE / 2, y + TILE_SIZE / 2);
+
+	x = TileX(next) * TILE_SIZE;
+	y = TileY(next) * TILE_SIZE;
+	/* get the height of the center of the next tile */
+	z2 = GetSlopeZ(x + TILE_SIZE / 2, y + TILE_SIZE / 2);
+
+	if (z2 - z1 > 1) {
+		/* 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... */
+}
+
+/**
+ * Mark tiles by mowing the grass when npf debug level >= 1.
+ * Will not work for multiplayer games, since it can (will) cause desyncs.
+ */
+static void NPFMarkTile(TileIndex tile)
+{
+#ifndef NO_DEBUG_MESSAGES
+	if (_debug_npf_level < 1 || _networking) return;
+	switch (GetTileType(tile)) {
+		case MP_RAILWAY:
+			/* DEBUG: mark visited tiles by mowing the grass under them ;-) */
+			if (!IsTileDepotType(tile, TRANSPORT_RAIL)) {
+				SetRailGroundType(tile, RAIL_GROUND_BARREN);
+				MarkTileDirtyByTile(tile);
+			}
+			break;
+
+		case MP_STREET:
+			if (!IsTileDepotType(tile, TRANSPORT_ROAD)) {
+				SetRoadside(tile, ROADSIDE_BARREN);
+				MarkTileDirtyByTile(tile);
+			}
+			break;
+
+		default:
+			break;
+	}
+#endif
+}
+
+static int32 NPFWaterPathCost(AyStar* as, AyStarNode* current, OpenListNode* parent)
+{
+	//TileIndex tile = current->tile;
+	int32 cost = 0;
+	Trackdir trackdir = (Trackdir)current->direction;
+
+	cost = _trackdir_length[trackdir]; /* Should be different for diagonal tracks */
+
+	if (IsBuoyTile(current->tile) && IsDiagonalTrackdir(trackdir))
+		cost += _patches.npf_buoy_penalty; /* A small penalty for going over buoys */
+
+	if (current->direction != NextTrackdir((Trackdir)parent->path.node.direction))
+		cost += _patches.npf_water_curve_penalty;
+
+	/* TODO More penalties? */
+
+	return cost;
+}
+
+/* Determine the cost of this node, for road tracks */
+static int32 NPFRoadPathCost(AyStar* as, AyStarNode* current, OpenListNode* parent)
+{
+	TileIndex tile = current->tile;
+	int32 cost = 0;
+
+	/* Determine base length */
+	switch (GetTileType(tile)) {
+		case MP_TUNNELBRIDGE:
+			cost = IsTunnel(tile) ? NPFTunnelCost(current) : NPFBridgeCost(current);
+			break;
+
+		case MP_STREET:
+			cost = NPF_TILE_LENGTH;
+			/* Increase the cost for level crossings */
+			if (IsLevelCrossing(tile)) cost += _patches.npf_crossing_penalty;
+			break;
+
+		default:
+			break;
+	}
+
+	/* Determine extra costs */
+
+	/* Check for slope */
+	cost += NPFSlopeCost(current);
+
+	/* Check for turns. Road vehicles only really drive diagonal, turns are
+	 * represented by non-diagonal tracks */
+	if (!IsDiagonalTrackdir(current->direction))
+		cost += _patches.npf_road_curve_penalty;
+
+	NPFMarkTile(tile);
+	DEBUG(npf, 4, "Calculating G for: (%d, %d). Result: %d", TileX(current->tile), TileY(current->tile), cost);
+	return cost;
+}
+
+
+/* Determine the cost of this node, for railway tracks */
+static int32 NPFRailPathCost(AyStar* as, AyStarNode* current, OpenListNode* parent)
+{
+	TileIndex tile = current->tile;
+	Trackdir trackdir = (Trackdir)current->direction;
+	int32 cost = 0;
+	/* HACK: We create a OpenListNode manually, so we can call EndNodeCheck */
+	OpenListNode new_node;
+
+	/* Determine base length */
+	switch (GetTileType(tile)) {
+		case MP_TUNNELBRIDGE:
+			cost = IsTunnel(tile) ? NPFTunnelCost(current) : NPFBridgeCost(current);
+			break;
+
+		case MP_RAILWAY:
+			cost = _trackdir_length[trackdir]; /* Should be different for diagonal tracks */
+			break;
+
+		case MP_STREET: /* Railway crossing */
+			cost = NPF_TILE_LENGTH;
+			break;
+
+		case 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 = NPF_TILE_LENGTH + _patches.npf_rail_station_penalty;
+			break;
+
+		default:
+			break;
+	}
+
+	/* Determine extra costs */
+
+	/* Check for signals */
+	if (IsTileType(tile, MP_RAILWAY) && HasSignalOnTrackdir(tile, trackdir)) {
+		/* Ordinary track with signals */
+		if (GetSignalStateByTrackdir(tile, trackdir) == SIGNAL_STATE_RED) {
+			/* Signal facing us is red */
+			if (!NPFGetFlag(current, NPF_FLAG_SEEN_SIGNAL)) {
+				/* Penalize the first signal we
+				 * encounter, if it is red */
+
+				/* Is this a presignal exit or combo? */
+				SignalType sigtype = GetSignalType(tile);
+				if (sigtype == SIGTYPE_EXIT || sigtype == SIGTYPE_COMBO) {
+					/* Penalise exit and combo signals differently (heavier) */
+					cost += _patches.npf_rail_firstred_exit_penalty;
+				} else {
+					cost += _patches.npf_rail_firstred_penalty;
+				}
+			}
+			/* Record the state of this signal */
+			NPFSetFlag(current, NPF_FLAG_LAST_SIGNAL_RED, true);
+		} else {
+			/* Record the state of this signal */
+			NPFSetFlag(current, NPF_FLAG_LAST_SIGNAL_RED, false);
+		}
+		NPFSetFlag(current, NPF_FLAG_SEEN_SIGNAL, true);
+	}
+
+	/* Penalise the tile if it is a target tile and the last signal was
+	 * red */
+	/* HACK: We create a new_node here so we can call EndNodeCheck. Ugly as hell
+	 * of course... */
+	new_node.path.node = *current;
+	if (as->EndNodeCheck(as, &new_node) == AYSTAR_FOUND_END_NODE && NPFGetFlag(current, NPF_FLAG_LAST_SIGNAL_RED))
+		cost += _patches.npf_rail_lastred_penalty;
+
+	/* Check for slope */
+	cost += NPFSlopeCost(current);
+
+	/* Check for turns */
+	if (current->direction != NextTrackdir((Trackdir)parent->path.node.direction))
+		cost += _patches.npf_rail_curve_penalty;
+	//TODO, with realistic acceleration, also the amount of straight track between
+	//      curves should be taken into account, as this affects the speed limit.
+
+	/* Check for reverse in depot */
+	if (IsTileDepotType(tile, TRANSPORT_RAIL) && as->EndNodeCheck(as, &new_node) != AYSTAR_FOUND_END_NODE) {
+		/* Penalise any depot tile that is not the last tile in the path. This
+		 * _should_ penalise every occurence of reversing in a depot (and only
+		 * that) */
+		cost += _patches.npf_rail_depot_reverse_penalty;
+	}
+
+	/* Check for occupied track */
+	//TODO
+
+	NPFMarkTile(tile);
+	DEBUG(npf, 4, "Calculating G for: (%d, %d). Result: %d", TileX(current->tile), TileY(current->tile), cost);
+	return cost;
+}
+
+/* Will find any depot */
+static int32 NPFFindDepot(AyStar* as, OpenListNode *current)
+{
+	/* It's not worth caching the result with NPF_FLAG_IS_TARGET here as below,
+	 * since checking the cache not that much faster than the actual check */
+	return IsTileDepotType(current->path.node.tile, as->user_data[NPF_TYPE]) ?
+		AYSTAR_FOUND_END_NODE : AYSTAR_DONE;
+}
+
+/* Will find a station identified using the NPFFindStationOrTileData */
+static int32 NPFFindStationOrTile(AyStar* as, OpenListNode *current)
+{
+	NPFFindStationOrTileData* fstd = (NPFFindStationOrTileData*)as->user_target;
+	AyStarNode *node = &current->path.node;
+	TileIndex tile = node->tile;
+
+	/* If GetNeighbours said we could get here, we assume the station type
+	 * is correct */
+	if (
+		(fstd->station_index == INVALID_STATION && tile == fstd->dest_coords) || /* We've found the tile, or */
+		(IsTileType(tile, MP_STATION) && GetStationIndex(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].
+ */
+static void NPFSaveTargetData(AyStar* as, OpenListNode* current)
+{
+	NPFFoundTargetData* ftd = (NPFFoundTargetData*)as->user_path;
+	ftd->best_trackdir = (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;
+}
+
+/**
+ * Finds out if a given player's vehicles are allowed to enter a given tile.
+ * @param owner    The owner of the vehicle.
+ * @param tile     The tile that is about to be entered.
+ * @param enterdir The direction from which the vehicle wants to enter the tile.
+ * @return         true if the vehicle can enter the tile.
+ * @todo           This function should be used in other places than just NPF,
+ *                 maybe moved to another file too.
+ */
+static bool VehicleMayEnterTile(Owner owner, TileIndex tile, DiagDirection enterdir)
+{
+	if (IsTileType(tile, MP_RAILWAY) ||           /* Rail tile (also rail depot) */
+			IsRailwayStationTile(tile) ||               /* Rail station tile */
+			IsTileDepotType(tile, TRANSPORT_ROAD) ||  /* Road depot tile */
+			IsRoadStopTile(tile) ||                /* Road station tile */
+			IsTileDepotType(tile, TRANSPORT_WATER)) { /* Water depot tile */
+		return IsTileOwner(tile, owner); /* You need to own these tiles entirely to use them */
+	}
+
+	switch (GetTileType(tile)) {
+		case MP_STREET:
+			/* rail-road crossing : are we looking at the railway part? */
+			if (IsLevelCrossing(tile) &&
+					DiagDirToAxis(enterdir) != GetCrossingRoadAxis(tile)) {
+				return IsTileOwner(tile, owner); /* Railway needs owner check, while the street is public */
+			}
+			break;
+
+		case MP_TUNNELBRIDGE:
+			if ((IsTunnel(tile) && GetTunnelTransportType(tile) == TRANSPORT_RAIL) ||
+					(IsBridge(tile) && GetBridgeTransportType(tile) == TRANSPORT_RAIL)) {
+				return IsTileOwner(tile, owner);
+			}
+			break;
+
+		default:
+			break;
+	}
+
+	return true; /* no need to check */
+}
+
+
+/**
+ * Returns the direction the exit of the depot on the given tile is facing.
+ */
+static DiagDirection GetDepotDirection(TileIndex tile, TransportType type)
+{
+	assert(IsTileDepotType(tile, type));
+
+	switch (type) {
+		case TRANSPORT_RAIL:  return GetRailDepotDirection(tile);
+		case TRANSPORT_ROAD:  return GetRoadDepotDirection(tile);
+		case TRANSPORT_WATER: return GetShipDepotDirection(tile);
+		default: return INVALID_DIAGDIR; /* Not reached */
+	}
+}
+
+
+/* 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 */
+static void NPFFollowTrack(AyStar* aystar, OpenListNode* current)
+{
+	Trackdir src_trackdir = (Trackdir)current->path.node.direction;
+	TileIndex src_tile = current->path.node.tile;
+	DiagDirection src_exitdir = TrackdirToExitdir(src_trackdir);
+	TileIndex dst_tile = INVALID_TILE;
+	int i;
+	TrackdirBits trackdirbits, ts;
+	TransportType type = aystar->user_data[NPF_TYPE];
+	bool override_dst_check = false;
+	/* Initialize to 0, so we can jump out (return) somewhere an have no neighbours */
+	aystar->num_neighbours = 0;
+	DEBUG(npf, 4, "Expanding: (%d, %d, %d) [%d]", TileX(src_tile), TileY(src_tile), src_trackdir, src_tile);
+
+	/* Find dest tile */
+	if (IsTunnelTile(src_tile) && GetTunnelDirection(src_tile) == 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 */
+		dst_tile = GetOtherTunnelEnd(src_tile);
+		override_dst_check = true;
+	} else if (IsBridgeTile(src_tile) && GetBridgeRampDirection(src_tile) == src_exitdir) {
+		dst_tile = GetOtherBridgeEnd(src_tile);
+		override_dst_check = true;
+	} else if (type != TRANSPORT_WATER && (IsRoadStopTile(src_tile) || IsTileDepotType(src_tile, type))) {
+		/* 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. */
+
+		DiagDirection exitdir;
+		/* Find out the exit direction first */
+		if (IsRoadStopTile(src_tile)) {
+			exitdir = GetRoadStopDir(src_tile);
+		} else { /* Train or road depot */
+			exitdir = GetDepotDirection(src_tile, type);
+		}
+
+		/* Let's see if were headed the right way into the depot */
+		if (src_trackdir == DiagdirToDiagTrackdir(ReverseDiagDir(exitdir))) {
+			/* We are headed inwards. We cannot go through the back of the depot.
+			 * For rail, we can now reverse. Reversing for road vehicles is never
+			 * useful, since you cannot take paths you couldn't take before
+			 * reversing (as with rail). */
+			if (type == TRANSPORT_RAIL) {
+				/* We can only reverse here, so we'll not consider this direction, but
+				 * jump ahead to the reverse direction.  It would be nicer to return
+				 * one neighbour here (the reverse trackdir of the one we are
+				 * considering now) and then considering that one to return the tracks
+				 * outside of the depot. But, because the code layout is cleaner this
+				 * way, we will just pretend we are reversed already */
+				src_trackdir = ReverseTrackdir(src_trackdir);
+				dst_tile = AddTileIndexDiffCWrap(src_tile, TileIndexDiffCByDiagDir(exitdir));
+			} else {
+				dst_tile = INVALID_TILE; /* Road vehicle heading inwards: dead end */
+			}
+		} else {
+			dst_tile = AddTileIndexDiffCWrap(src_tile, TileIndexDiffCByDiagDir(exitdir));
+		}
+	} else {
+		/* This a normal tile, a bridge, a tunnel exit, etc. */
+		dst_tile = AddTileIndexDiffCWrap(src_tile, TileIndexDiffCByDiagDir(TrackdirToExitdir(src_trackdir)));
+	}
+	if (dst_tile == INVALID_TILE) {
+		/* We reached the border of the map */
+		/* TODO Nicer control flow for this */
+		return;
+	}
+
+	/* I can't enter a tunnel entry/exit tile from a tile above the tunnel. Note
+	 * that I can enter the tunnel from a tile below the tunnel entrance. This
+	 * solves the problem of vehicles wanting to drive off a tunnel entrance */
+	if (!override_dst_check) {
+		if (IsTileType(dst_tile, MP_TUNNELBRIDGE)) {
+			if (IsTunnel(dst_tile)) {
+				if (GetTunnelDirection(dst_tile) != src_exitdir) return;
+			} else {
+				if (GetBridgeRampDirection(dst_tile) != src_exitdir) return;
+			}
+		}
+	}
+
+	/* check correct rail type (mono, maglev, etc) */
+	if (type == TRANSPORT_RAIL) {
+		RailType dst_type = GetTileRailType(dst_tile, src_trackdir);
+		if (!HASBIT(aystar->user_data[NPF_RAILTYPES], dst_type))
+			return;
+	}
+
+	/* Check the owner of the tile */
+	if (!VehicleMayEnterTile(aystar->user_data[NPF_OWNER], dst_tile, TrackdirToExitdir(src_trackdir))) {
+		return;
+	}
+
+	/* Determine available tracks */
+	if (type != TRANSPORT_WATER && (IsRoadStopTile(dst_tile) || IsTileDepotType(dst_tile, type))){
+		/* Road stations and road and train depots return 0 on GTTS, so we have to do this by hand... */
+		DiagDirection exitdir;
+		if (IsRoadStopTile(dst_tile)) {
+			exitdir = GetRoadStopDir(dst_tile);
+		} else { /* Road or train depot */
+			exitdir = GetDepotDirection(dst_tile, type);
+		}
+		/* Find the trackdirs that are available for a depot or station with this
+		 * orientation. They are only "inwards", since we are reaching this tile
+		 * from some other tile. This prevents vehicles driving into depots from
+		 * the back */
+		ts = TrackdirToTrackdirBits(DiagdirToDiagTrackdir(ReverseDiagDir(exitdir)));
+	} else {
+		ts = GetTileTrackStatus(dst_tile, type);
+	}
+	trackdirbits = ts & TRACKDIR_BIT_MASK; /* Filter out signal status and the unused bits */
+
+	DEBUG(npf, 4, "Next node: (%d, %d) [%d], possible trackdirs: 0x%X", TileX(dst_tile), TileY(dst_tile), dst_tile, trackdirbits);
+	/* Select only trackdirs we can reach from our current trackdir */
+	trackdirbits &= TrackdirReachesTrackdirs(src_trackdir);
+	if (_patches.forbid_90_deg && (type == TRANSPORT_RAIL || type == TRANSPORT_WATER)) /* Filter out trackdirs that would make 90 deg turns for trains */
+		trackdirbits &= ~TrackdirCrossesTrackdirs(src_trackdir);
+
+	DEBUG(npf, 6, "After filtering: (%d, %d), possible trackdirs: 0x%X", TileX(dst_tile), TileY(dst_tile), trackdirbits);
+
+	i = 0;
+	/* Enumerate possible track */
+	while (trackdirbits != 0) {
+		Trackdir dst_trackdir;
+		dst_trackdir =  FindFirstBit2x64(trackdirbits);
+		trackdirbits = KillFirstBit2x64(trackdirbits);
+		DEBUG(npf, 5, "Expanded into trackdir: %d, remaining trackdirs: 0x%X", dst_trackdir, trackdirbits);
+
+		/* Check for oneway signal against us */
+		if (IsTileType(dst_tile, MP_RAILWAY) && GetRailTileType(dst_tile) == RAIL_TILE_SIGNALS) {
+			if (HasSignalOnTrackdir(dst_tile, ReverseTrackdir(dst_trackdir)) && !HasSignalOnTrackdir(dst_tile, dst_trackdir))
+				// if one way signal not pointing towards us, stop going in this direction.
+				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. reverse_penalty is applied to all routes that
+ * originate from the second start node.
+ * 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.
+ */
+static NPFFoundTargetData NPFRouteInternal(AyStarNode* start1, AyStarNode* start2, NPFFindStationOrTileData* target, AyStar_EndNodeCheck target_proc, AyStar_CalculateH heuristic_proc, TransportType type, Owner owner, RailTypeMask railtypes, uint reverse_penalty)
+{
+	int r;
+	NPFFoundTargetData result;
+
+	/* Initialize procs */
+	_npf_aystar.CalculateH = heuristic_proc;
+	_npf_aystar.EndNodeCheck = target_proc;
+	_npf_aystar.FoundEndNode = NPFSaveTargetData;
+	_npf_aystar.GetNeighbours = NPFFollowTrack;
+	switch (type) {
+		default: NOT_REACHED();
+		case TRANSPORT_RAIL:  _npf_aystar.CalculateG = NPFRailPathCost;  break;
+		case TRANSPORT_ROAD:  _npf_aystar.CalculateG = NPFRoadPathCost;  break;
+		case TRANSPORT_WATER: _npf_aystar.CalculateG = NPFWaterPathCost; break;
+	}
+
+	/* Initialize Start Node(s) */
+	start1->user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
+	start1->user_data[NPF_NODE_FLAGS] = 0;
+	_npf_aystar.addstart(&_npf_aystar, start1, 0);
+	if (start2) {
+		start2->user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
+		start2->user_data[NPF_NODE_FLAGS] = 0;
+		NPFSetFlag(start2, NPF_FLAG_REVERSE, true);
+		_npf_aystar.addstart(&_npf_aystar, start2, reverse_penalty);
+	}
+
+	/* Initialize result */
+	result.best_bird_dist = (uint)-1;
+	result.best_path_dist = (uint)-1;
+	result.best_trackdir = INVALID_TRACKDIR;
+	_npf_aystar.user_path = &result;
+
+	/* Initialize target */
+	_npf_aystar.user_target = target;
+
+	/* Initialize user_data */
+	_npf_aystar.user_data[NPF_TYPE] = type;
+	_npf_aystar.user_data[NPF_OWNER] = owner;
+	_npf_aystar.user_data[NPF_RAILTYPES] = railtypes;
+
+	/* GO! */
+	r = AyStarMain_Main(&_npf_aystar);
+	assert(r != AYSTAR_STILL_BUSY);
+
+	if (result.best_bird_dist != 0) {
+		if (target != NULL) {
+			DEBUG(npf, 1, "Could not find route to tile 0x%X from 0x%X.", target->dest_coords, start1->tile);
+		} else {
+			/* Assumption: target == NULL, so we are looking for a depot */
+			DEBUG(npf, 1, "Could not find route to a depot from tile 0x%X.", start1->tile);
+		}
+
+	}
+	return result;
+}
+
+NPFFoundTargetData NPFRouteToStationOrTileTwoWay(TileIndex tile1, Trackdir trackdir1, TileIndex tile2, Trackdir trackdir2, NPFFindStationOrTileData* target, TransportType type, Owner owner, RailTypeMask railtypes)
+{
+	AyStarNode start1;
+	AyStarNode start2;
+
+	start1.tile = tile1;
+	start2.tile = tile2;
+	/* We set this in case the target is also the start tile, we will just
+	 * return a not found then */
+	start1.user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
+	start1.direction = trackdir1;
+	start2.direction = trackdir2;
+	start2.user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
+
+	return NPFRouteInternal(&start1, (IsValidTile(tile2) ? &start2 : NULL), target, NPFFindStationOrTile, NPFCalcStationOrTileHeuristic, type, owner, railtypes, 0);
+}
+
+NPFFoundTargetData NPFRouteToStationOrTile(TileIndex tile, Trackdir trackdir, NPFFindStationOrTileData* target, TransportType type, Owner owner, RailTypeMask railtypes)
+{
+	return NPFRouteToStationOrTileTwoWay(tile, trackdir, INVALID_TILE, 0, target, type, owner, railtypes);
+}
+
+NPFFoundTargetData NPFRouteToDepotBreadthFirstTwoWay(TileIndex tile1, Trackdir trackdir1, TileIndex tile2, Trackdir trackdir2, TransportType type, Owner owner, RailTypeMask railtypes, uint reverse_penalty)
+{
+	AyStarNode start1;
+	AyStarNode start2;
+
+	start1.tile = tile1;
+	start2.tile = tile2;
+	/* We set this in case the target is also the start tile, we will just
+	 * return a not found then */
+	start1.user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
+	start1.direction = trackdir1;
+	start2.direction = trackdir2;
+	start2.user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
+
+	/* perform a breadth first search. Target is NULL,
+	 * since we are just looking for any depot...*/
+	return NPFRouteInternal(&start1, (IsValidTile(tile2) ? &start2 : NULL), NULL, NPFFindDepot, NPFCalcZero, type, owner, railtypes, reverse_penalty);
+}
+
+NPFFoundTargetData NPFRouteToDepotBreadthFirst(TileIndex tile, Trackdir trackdir, TransportType type, Owner owner, RailTypeMask railtypes)
+{
+	return NPFRouteToDepotBreadthFirstTwoWay(tile, trackdir, INVALID_TILE, 0, type, owner, railtypes, 0);
+}
+
+NPFFoundTargetData NPFRouteToDepotTrialError(TileIndex tile, Trackdir trackdir, TransportType type, Owner owner, RailTypeMask railtypes)
+{
+	/* 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;
+	int r;
+	NPFFoundTargetData best_result = {(uint)-1, (uint)-1, INVALID_TRACKDIR, {INVALID_TILE, 0, {0, 0}}};
+	NPFFoundTargetData result;
+	NPFFindStationOrTileData target;
+	AyStarNode start;
+	Depot* current;
+	Depot *depot;
+
+	init_InsSort(&depots);
+	/* Okay, let's find all depots that we can use first */
+	FOR_ALL_DEPOTS(depot) {
+		/* Check if this is really a valid depot, it is of the needed type and
+		 * owner */
+		if (IsTileDepotType(depot->xy, type) && IsTileOwner(depot->xy, owner))
+			/* If so, let's add it to the queue, sorted by distance */
+			depots.push(&depots, depot, DistanceManhattan(tile, depot->xy));
+	}
+
+	/* Now, let's initialise the aystar */
+
+	/* Initialize procs */
+	_npf_aystar.CalculateH = NPFCalcStationOrTileHeuristic;
+	_npf_aystar.EndNodeCheck = NPFFindStationOrTile;
+	_npf_aystar.FoundEndNode = NPFSaveTargetData;
+	_npf_aystar.GetNeighbours = NPFFollowTrack;
+	switch (type) {
+		default: NOT_REACHED();
+		case TRANSPORT_RAIL:  _npf_aystar.CalculateG = NPFRailPathCost;  break;
+		case TRANSPORT_ROAD:  _npf_aystar.CalculateG = NPFRoadPathCost;  break;
+		case TRANSPORT_WATER: _npf_aystar.CalculateG = NPFWaterPathCost; break;
+	}
+
+	/* Initialize target */
+	target.station_index = INVALID_STATION; /* We will initialize dest_coords inside the loop below */
+	_npf_aystar.user_target = &target;
+
+	/* Initialize user_data */
+	_npf_aystar.user_data[NPF_TYPE] = type;
+	_npf_aystar.user_data[NPF_OWNER] = owner;
+
+	/* 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;
+	best_result.best_bird_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] = INVALID_TRACKDIR;
+		start.user_data[NPF_NODE_FLAGS] = 0;
+		_npf_aystar.addstart(&_npf_aystar, &start, 0);
+
+		/* Initialize result */
+		result.best_bird_dist = (uint)-1;
+		result.best_path_dist = (uint)-1;
+		result.best_trackdir = INVALID_TRACKDIR;
+
+		/* 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(npf, 1, "Could not find route to any depot from tile 0x%X.", tile);
+	}
+	return best_result;
+}
+
+void InitializeNPF(void)
+{
+	init_AyStar(&_npf_aystar, NPFHash, NPF_HASH_SIZE);
+	_npf_aystar.loops_per_tick = 0;
+	_npf_aystar.max_path_cost = 0;
+	//_npf_aystar.max_search_nodes = 0;
+	/* We will limit the number of nodes for now, until we have a better
+	 * solution to really fix performance */
+	_npf_aystar.max_search_nodes = _patches.npf_max_search_nodes;
+}
+
+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.dest;
+		/* Let's take the closest tile of the station as our target for trains */
+		fstd->dest_coords = CalcClosestStationTile(v->current_order.dest, v->tile);
+	} else {
+		fstd->dest_coords = v->dest_tile;
+		fstd->station_index = INVALID_STATION;
+	}
+}