OpenTTD/src/pathfinder/yapf/yapf.h

/* $Id$ */

/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file yapf.h Entry point for OpenTTD to YAPF. */

#ifndef  YAPF_H
#define  YAPF_H

#include "../../direction_type.h"
#include "../../station_type.h"
#include "../pathfinder_type.h"

/**
 * Finds the best path for given ship using YAPF.
 * @param v        the ship that needs to find a path
 * @param tile     the tile to find the path from (should be next tile the ship is about to enter)
 * @param enterdir diagonal direction which the ship will enter this new tile from
 * @param tracks   available tracks on the new tile (to choose from)
 * @return         the best trackdir for next turn or INVALID_TRACK if the path could not be found
 */
Track YapfChooseShipTrack(const Ship *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks);

/** Finds the best path for given road vehicle.
 * @param v        the RV that needs to find a path
 * @param tile     the tile to find the path from (should be next tile the RV is about to enter)
 * @param enterdir diagonal direction which the RV will enter this new tile from
 * @return         the best trackdir for next turn or INVALID_TRACKDIR if the path could not be found
 */
Trackdir YapfChooseRoadTrack(const RoadVehicle *v, TileIndex tile, DiagDirection enterdir);

/**
 * Finds the best path for given train using YAPF.
 * @param v        the train that needs to find a path
 * @param tile     the tile to find the path from (should be next tile the train is about to enter)
 * @param enterdir diagonal direction which the RV will enter this new tile from
 * @param tracks   available trackdirs on the new tile (to choose from)
 * @param path_not_found [out] true is returned if no path can be found (returned Trackdir is only a 'guess')
 * @param reserve_track indicates whether YAPF should try to reserve the found path
 * @param target   [out] the target tile of the reservation, free is set to true if path was reserved
 * @return         the best track for next turn
 */
Track YapfTrainChooseTrack(const Train *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks, bool *path_not_found, bool reserve_track, struct PBSTileInfo *target);

/** Used by RV multistop feature to find the nearest road stop that has a free slot.
 * @param v      RV (its current tile will be the origin)
 * @param tile   destination tile
 * @return       distance from origin tile to the destination (number of road tiles) or UINT_MAX if path not found
 */
uint YapfRoadVehDistanceToTile(const RoadVehicle *v, TileIndex tile);

/** Used to determinine the closest reachable compatible road stop for a given vehicle.
 * @param v            vehicle that needs to go to the road stop
 * @param station      the station the road stop must belong to
 * @param stop_tile    receives the stop tile if a stop was found
 * @return             true if stop was found.
 */
bool YapfFindNearestRoadVehicleCompatibleStop(const RoadVehicle *v, StationID station, TileIndex *stop_tile);

/** Used when user sends road vehicle to the nearest depot or if road vehicle needs servicing.
 * @param v            vehicle that needs to go to some depot
 * @param max_distance max distance (number of track tiles) from the current vehicle position
 *                     (used also as optimization - the pathfinder can stop path finding if max_distance
 *                     was reached and no depot was seen)
 * @param depot_tile   receives the depot tile if depot was found
 * @return             true if depot was found.
 */
bool YapfFindNearestRoadDepot(const RoadVehicle *v, int max_distance, TileIndex *depot_tile);

/**
 * Used when user sends train to the nearest depot or if train needs servicing using YAPF.
 * @param v            train that needs to go to some depot
 * @param max_distance max distance (number of track tiles) from the current train position
 *                     (used also as optimization - the pathfinder can stop path finding if max_distance
 *                     was reached and no depot was seen)
 * @return             the data about the depot
 */
FindDepotData YapfTrainFindNearestDepot(const Train *v, int max_distance);

/**
 * Returns true if it is better to reverse the train before leaving station using YAPF.
 * @param v the train leaving the station
 * @return true if reversing is better
 */
bool YapfTrainCheckReverse(const Train *v);

/**
 * Try to extend the reserved path of a train to the nearest safe tile using YAPF.
 *
 * @param v    The train that needs to find a safe tile.
 * @param tile Last tile of the current reserved path.
 * @param td   Last trackdir of the current reserved path.
 * @param override_railtype Should all physically compatible railtypes be searched, even if the vehicle can't run on them on its own?
 * @return True if the path could be extended to a safe tile.
 */
bool YapfTrainFindNearestSafeTile(const Train *v, TileIndex tile, Trackdir td, bool override_railtype);

/** Use this function to notify YAPF that track layout (or signal configuration) has change */
void YapfNotifyTrackLayoutChange(TileIndex tile, Track track);

/** performance measurement helpers */
void *NpfBeginInterval();
int NpfEndInterval(void *perf);


extern int _aystar_stats_open_size;
extern int _aystar_stats_closed_size;


/** Base tile length units */
enum {
	YAPF_TILE_LENGTH = 100,
	YAPF_TILE_CORNER_LENGTH = 71,

	/**
	 * This penalty is the equivalent of "infite", which means that paths that
	 * get this penalty will be chosen, but only if there is no other route
	 * without it. Be careful with not applying this penalty to often, or the
	 * total path cost might overflow..
	 * For now, this is just a Very Big Penalty, we might actually implement
	 * this in a nicer way :-)
	 */
	YAPF_INFINITE_PENALTY = 1000 * YAPF_TILE_LENGTH,
};

#endif /* YAPF_H */