rubidium@8101: /* $Id$ */
rubidium@8101: 
rubidium@8101: /** @file track_func.h Different conversion functions from one kind of track to another. */
rubidium@8101: 
rubidium@8101: #ifndef TRACK_FUNC_H
rubidium@8101: #define TRACK_FUNC_H
rubidium@8101: 
rubidium@8113: #include "core/bitmath_func.hpp"
rubidium@8101: #include "track_type.h"
rubidium@8101: #include "direction_type.h"
rubidium@8108: #include "slope_func.h"
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Convert an Axis to the corresponding Track
rubidium@8101:  * AXIS_X -> TRACK_X
rubidium@8101:  * AXIS_Y -> TRACK_Y
rubidium@8101:  * Uses the fact that they share the same internal encoding
rubidium@8101:  *
rubidium@8101:  * @param a the axis to convert
rubidium@8101:  * @return the track corresponding to the axis
rubidium@8101:  */
rubidium@8101: static inline Track AxisToTrack(Axis a)
rubidium@8101: {
rubidium@8101: 	return (Track)a;
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Maps a Track to the corresponding TrackBits value
rubidium@8101:  * @param track the track to convert
rubidium@8101:  * @return the converted TrackBits value of the track
rubidium@8101:  */
rubidium@8101: static inline TrackBits TrackToTrackBits(Track track)
rubidium@8101: {
rubidium@8101: 	return (TrackBits)(1 << track);
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Maps an Axis to the corresponding TrackBits value
rubidium@8101:  * @param a the axis to convert
rubidium@8101:  * @return the converted TrackBits value of the axis
rubidium@8101:  */
rubidium@8101: static inline TrackBits AxisToTrackBits(Axis a)
rubidium@8101: {
rubidium@8101: 	return TrackToTrackBits(AxisToTrack(a));
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Returns a single horizontal/vertical trackbit, that is in a specific tile corner.
rubidium@8101:  *
rubidium@8101:  * @param corner The corner of a tile.
rubidium@8101:  * @return The TrackBits of the track in the corner.
rubidium@8101:  */
rubidium@8101: static inline TrackBits CornerToTrackBits(Corner corner)
rubidium@8101: {
rubidium@8101: 	extern const TrackBits _corner_to_trackbits[];
rubidium@8101: 	assert(IsValidCorner(corner));
rubidium@8101: 	return _corner_to_trackbits[corner];
rubidium@8101: }
rubidium@8101: 
rubidium@8101: 
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Maps a Trackdir to the corresponding TrackdirBits value
rubidium@8101:  * @param trackdir the track direction to convert
rubidium@8101:  * @return the converted TrackdirBits value
rubidium@8101:  */
rubidium@8101: static inline TrackdirBits TrackdirToTrackdirBits(Trackdir trackdir)
rubidium@8101: {
rubidium@8101: 	return (TrackdirBits)(1 << trackdir);
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Removes first Track from TrackBits and returns it
rubidium@8101:  *
rubidium@8101:  * This function searchs for the first bit in the TrackBits,
rubidium@8101:  * remove this bit from the parameter and returns the found
rubidium@8101:  * bit as Track value. It returns INVALID_TRACK if the
rubidium@8101:  * parameter was TRACK_BIT_NONE or INVALID_TRACK_BIT. This
rubidium@8101:  * is basically used in while-loops to get up to 6 possible
rubidium@8101:  * tracks on a tile until the parameter becomes TRACK_BIT_NONE.
rubidium@8101:  *
rubidium@8101:  * @param tracks The value with the TrackBits
rubidium@8101:  * @return The first Track from the TrackBits value
rubidium@8101:  * @see FindFirstTrack
rubidium@8101:  */
rubidium@8101: static inline Track RemoveFirstTrack(TrackBits *tracks)
rubidium@8101: {
rubidium@8101: 	if (*tracks != TRACK_BIT_NONE && *tracks != INVALID_TRACK_BIT) {
rubidium@8101: 		Track first = (Track)FIND_FIRST_BIT(*tracks);
rubidium@8101: 		ClrBit(*tracks, first);
rubidium@8101: 		return first;
rubidium@8101: 	}
rubidium@8101: 	return INVALID_TRACK;
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Removes first Trackdir from TrackdirBits and returns it
rubidium@8101:  *
rubidium@8101:  * This function searchs for the first bit in the TrackdirBits parameter,
rubidium@8101:  * remove this bit from the parameter and returns the fnound bit as
rubidium@8101:  * Trackdir value. It returns INVALID_TRACKDIR if the trackdirs is
rubidium@8101:  * TRACKDIR_BIT_NONE or INVALID_TRACKDIR_BIT. This is basically used in a
rubidium@8101:  * while-loop to get all track-directions step by step until the value
rubidium@8101:  * reaches TRACKDIR_BIT_NONE.
rubidium@8101:  *
rubidium@8101:  * @param trackdirs The value with the TrackdirBits
rubidium@8101:  * @return The first Trackdir from the TrackdirBits value
rubidium@8101:  * @see FindFirstTrackdir
rubidium@8101:  */
rubidium@8101: static inline Trackdir RemoveFirstTrackdir(TrackdirBits *trackdirs)
rubidium@8101: {
rubidium@8101: 	if (*trackdirs != TRACKDIR_BIT_NONE && *trackdirs != INVALID_TRACKDIR_BIT) {
rubidium@8101: 		Trackdir first = (Trackdir)FindFirstBit2x64(*trackdirs);
rubidium@8101: 		ClrBit(*trackdirs, first);
rubidium@8101: 		return first;
rubidium@8101: 	}
rubidium@8101: 	return INVALID_TRACKDIR;
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Returns first Track from TrackBits or INVALID_TRACK
rubidium@8101:  *
rubidium@8101:  * This function returns the first Track found in the TrackBits value as Track-value.
rubidium@8101:  * It returns INVALID_TRACK if the parameter is TRACK_BIT_NONE or INVALID_TRACK_BIT.
rubidium@8101:  *
rubidium@8101:  * @param tracks The TrackBits value
rubidium@8101:  * @return The first Track found or INVALID_TRACK
rubidium@8101:  * @see RemoveFirstTrack
rubidium@8101:  */
rubidium@8101: static inline Track FindFirstTrack(TrackBits tracks)
rubidium@8101: {
rubidium@8101: 	return (tracks != TRACK_BIT_NONE && tracks != INVALID_TRACK_BIT) ? (Track)FIND_FIRST_BIT(tracks) : INVALID_TRACK;
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Converts TrackBits to Track.
rubidium@8101:  *
rubidium@8101:  * This function converts a TrackBits value to a Track value. As it
rubidium@8101:  * is not possible to convert two or more tracks to one track the
rubidium@8101:  * parameter must contain only one track or be the INVALID_TRACK_BIT value.
rubidium@8101:  *
rubidium@8101:  * @param tracks The TrackBits value to convert
rubidium@8101:  * @return The Track from the value or INVALID_TRACK
rubidium@8101:  * @pre tracks must contains only one Track or be INVALID_TRACK_BIT
rubidium@8101:  */
rubidium@8101: static inline Track TrackBitsToTrack(TrackBits tracks)
rubidium@8101: {
rubidium@8101: 	assert(tracks == INVALID_TRACK_BIT || (tracks != TRACK_BIT_NONE && KillFirstBit(tracks & TRACK_BIT_MASK) == TRACK_BIT_NONE));
rubidium@8101: 	return tracks != INVALID_TRACK_BIT ? (Track)FIND_FIRST_BIT(tracks & TRACK_BIT_MASK) : INVALID_TRACK;
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Returns first Trackdir from TrackdirBits or INVALID_TRACKDIR
rubidium@8101:  *
rubidium@8101:  * This function returns the first Trackdir in the given TrackdirBits value or
rubidium@8101:  * INVALID_TRACKDIR if the value is TRACKDIR_BIT_NONE. The TrackdirBits must
rubidium@8101:  * not be INVALID_TRACKDIR_BIT.
rubidium@8101:  *
rubidium@8101:  * @param trackdirs The TrackdirBits value
rubidium@8101:  * @return The first Trackdir from the TrackdirBits or INVALID_TRACKDIR on TRACKDIR_BIT_NONE.
rubidium@8101:  * @pre trackdirs must not be INVALID_TRACKDIR_BIT
rubidium@8101:  * @see RemoveFirstTrackdir
rubidium@8101:  */
rubidium@8101: static inline Trackdir FindFirstTrackdir(TrackdirBits trackdirs)
rubidium@8101: {
rubidium@8101: 	assert((trackdirs & ~TRACKDIR_BIT_MASK) == TRACKDIR_BIT_NONE);
rubidium@8101: 	return (trackdirs != TRACKDIR_BIT_NONE) ? (Trackdir)FindFirstBit2x64(trackdirs) : INVALID_TRACKDIR;
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Checks if a Track is valid.
rubidium@8101:  *
rubidium@8101:  * @param track The value to check
rubidium@8101:  * @return true if the given value is a valid track.
rubidium@8101:  * @note Use this in an assert()
rubidium@8101:  */
rubidium@8101: static inline bool IsValidTrack(Track track)
rubidium@8101: {
rubidium@8101: 	return track < TRACK_END;
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Checks if a Trackdir is valid.
rubidium@8101:  *
rubidium@8101:  * @param trackdir The value to check
rubidium@8101:  * @return true if the given valie is a valid Trackdir
rubidium@8101:  * @note Use this in an assert()
rubidium@8101:  */
rubidium@8101: static inline bool IsValidTrackdir(Trackdir trackdir)
rubidium@8101: {
rubidium@8101: 	return (TrackdirToTrackdirBits(trackdir) & TRACKDIR_BIT_MASK) != 0;
rubidium@8101: }
rubidium@8101: 
rubidium@8101: 
rubidium@8101: /*
rubidium@8101:  * Functions describing logical relations between Tracks, TrackBits, Trackdirs
rubidium@8101:  * TrackdirBits, Direction and DiagDirections.
rubidium@8101:  */
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Maps a trackdir to the reverse trackdir.
rubidium@8101:  *
rubidium@8101:  * Returns the reverse trackdir of a Trackdir value. The reverse trackdir
rubidium@8101:  * is the same track with the other direction on it.
rubidium@8101:  *
rubidium@8101:  * @param trackdir The Trackdir value
rubidium@8101:  * @return The reverse trackdir
rubidium@8101:  * @pre trackdir must not be INVALID_TRACKDIR
rubidium@8101:  */
rubidium@8101: static inline Trackdir ReverseTrackdir(Trackdir trackdir)
rubidium@8101: {
rubidium@8101: 	assert(trackdir != INVALID_TRACKDIR);
rubidium@8101: 	return (Trackdir)(trackdir ^ 8);
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Returns the Track that a given Trackdir represents
rubidium@8101:  *
rubidium@8101:  * This function filters the Track which is used in the Trackdir value and
rubidium@8101:  * returns it as a Track value.
rubidium@8101:  *
rubidium@8101:  * @param trackdir The trackdir value
rubidium@8101:  * @return The Track which is used in the value
rubidium@8101:  */
rubidium@8101: static inline Track TrackdirToTrack(Trackdir trackdir)
rubidium@8101: {
rubidium@8101: 	return (Track)(trackdir & 0x7);
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Returns a Trackdir for the given Track
rubidium@8101:  *
rubidium@8101:  * Since every Track corresponds to two Trackdirs, we choose the
rubidium@8101:  * one which points between NE and S. Note that the actual
rubidium@8101:  * implementation is quite futile, but this might change
rubidium@8101:  * in the future.
rubidium@8101:  *
rubidium@8101:  * @param track The given Track
rubidium@8101:  * @return The Trackdir from the given Track
rubidium@8101:  */
rubidium@8101: static inline Trackdir TrackToTrackdir(Track track)
rubidium@8101: {
rubidium@8101: 	return (Trackdir)track;
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Returns a TrackdirBit mask from a given Track
rubidium@8101:  *
rubidium@8101:  * The TrackdirBit mask contains the two TrackdirBits that
rubidium@8101:  * correspond with the given Track (one for each direction).
rubidium@8101:  *
rubidium@8101:  * @param track The track to get the TrackdirBits from
rubidium@8101:  * @return The TrackdirBits which the selected tracks
rubidium@8101:  */
rubidium@8101: static inline TrackdirBits TrackToTrackdirBits(Track track)
rubidium@8101: {
rubidium@8101: 	Trackdir td = TrackToTrackdir(track);
rubidium@8101: 	return (TrackdirBits)(TrackdirToTrackdirBits(td) | TrackdirToTrackdirBits(ReverseTrackdir(td)));
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Discards all directional information from a TrackdirBits value
rubidium@8101:  *
rubidium@8101:  * Any Track which is present in either direction will be present in the result.
rubidium@8101:  *
rubidium@8101:  * @param bits The TrackdirBits to get the TrackBits from
rubidium@8101:  * @return The TrackBits
rubidium@8101:  */
rubidium@8101: static inline TrackBits TrackdirBitsToTrackBits(TrackdirBits bits)
rubidium@8101: {
rubidium@8101: 	return (TrackBits)((bits | (bits >> 8)) & TRACK_BIT_MASK);
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
frosch@8616:  * Converts TrackBits to TrackdirBits while allowing both directions.
frosch@8616:  *
frosch@8616:  * @param bits The TrackBits
smatz@9224:  * @return The TrackdirBits containing of bits in both directions.
frosch@8616:  */
frosch@8616: static inline TrackdirBits TrackBitsToTrackdirBits(TrackBits bits)
frosch@8616: {
frosch@8616: 	return (TrackdirBits)(bits * 0x101);
frosch@8616: }
frosch@8616: 
frosch@8616: /**
frosch@8616:  * Returns the present-trackdir-information of a TrackStatus.
frosch@8616:  *
frosch@8616:  * @param ts The TrackStatus returned by GetTileTrackStatus()
frosch@8616:  * @return the present trackdirs
frosch@8616:  */
frosch@8616: static inline TrackdirBits TrackStatusToTrackdirBits(TrackStatus ts)
frosch@8616: {
frosch@8616: 	return (TrackdirBits)(ts & TRACKDIR_BIT_MASK);
frosch@8616: }
frosch@8616: 
frosch@8616: /**
frosch@8616:  * Returns the present-track-information of a TrackStatus.
frosch@8616:  *
frosch@8616:  * @param ts The TrackStatus returned by GetTileTrackStatus()
frosch@8616:  * @return the present tracks
frosch@8616:  */
frosch@8616: static inline TrackBits TrackStatusToTrackBits(TrackStatus ts)
frosch@8616: {
frosch@8616: 	return TrackdirBitsToTrackBits(TrackStatusToTrackdirBits(ts));
frosch@8616: }
frosch@8616: 
frosch@8616: /**
frosch@8616:  * Returns the red-signal-information of a TrackStatus.
frosch@8616:  *
frosch@8616:  * Note: The result may contain red signals for non-present tracks.
frosch@8616:  *
frosch@8616:  * @param ts The TrackStatus returned by GetTileTrackStatus()
frosch@8616:  * @return the The trackdirs that are blocked by red-signals
frosch@8616:  */
frosch@8616: static inline TrackdirBits TrackStatusToRedSignals(TrackStatus ts)
frosch@8616: {
frosch@8616: 	return (TrackdirBits)((ts >> 16) & TRACKDIR_BIT_MASK);
frosch@8616: }
frosch@8616: 
frosch@8616: /**
frosch@8616:  * Builds a TrackStatus
frosch@8616:  *
frosch@8616:  * @param trackdirbits present trackdirs
frosch@8616:  * @param red_signals red signals
frosch@8616:  * @return the TrackStatus representing the given information
frosch@8616:  */
frosch@8616: static inline TrackStatus CombineTrackStatus(TrackdirBits trackdirbits, TrackdirBits red_signals)
frosch@8616: {
frosch@8616: 	return (TrackStatus)(trackdirbits | (red_signals << 16));
frosch@8616: }
frosch@8616: 
frosch@8616: /**
rubidium@8101:  * Maps a trackdir to the trackdir that you will end up on if you go straight
rubidium@8101:  * ahead.
rubidium@8101:  *
rubidium@8101:  * This will be the same trackdir for diagonal trackdirs, but a
rubidium@8101:  * different (alternating) one for straight trackdirs
rubidium@8101:  *
rubidium@8101:  * @param trackdir The given trackdir
rubidium@8101:  * @return The next Trackdir value of the next tile.
rubidium@8101:  */
rubidium@8101: static inline Trackdir NextTrackdir(Trackdir trackdir)
rubidium@8101: {
rubidium@8101: 	extern const Trackdir _next_trackdir[TRACKDIR_END];
rubidium@8101: 	return _next_trackdir[trackdir];
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Maps a track to all tracks that make 90 deg turns with it.
rubidium@8101:  *
rubidium@8101:  * For the diagonal directions these are the complement of the
rubidium@8101:  * direction, for the straight directions these are the
rubidium@8101:  * two vertical or horizontal tracks, depend on the given direction
rubidium@8101:  *
rubidium@8101:  * @param track The given track
rubidium@8101:  * @return The TrackBits with the tracks marked which cross the given track by 90 deg.
rubidium@8101:  */
rubidium@8101: static inline TrackBits TrackCrossesTracks(Track track)
rubidium@8101: {
rubidium@8101: 	extern const TrackBits _track_crosses_tracks[TRACK_END];
rubidium@8101: 	return _track_crosses_tracks[track];
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Maps a trackdir to the (4-way) direction the tile is exited when following
rubidium@8101:  * that trackdir.
rubidium@8101:  *
rubidium@8101:  * For the diagonal directions these are the same directions. For
rubidium@8101:  * the straight directions these are the directions from the imagined
rubidium@8101:  * base-tile to the bordering tile which will be joined if the given
rubidium@8101:  * straight direction is leaved from the base-tile.
rubidium@8101:  *
rubidium@8101:  * @param trackdir The given track direction
rubidium@8101:  * @return The direction which points to the resulting tile if following the Trackdir
rubidium@8101:  */
rubidium@8101: static inline DiagDirection TrackdirToExitdir(Trackdir trackdir)
rubidium@8101: {
rubidium@8101: 	extern const DiagDirection _trackdir_to_exitdir[TRACKDIR_END];
rubidium@8101: 	return _trackdir_to_exitdir[trackdir];
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Maps a track and an (4-way) dir to the trackdir that represents the track
rubidium@8101:  * with the exit in the given direction.
rubidium@8101:  *
rubidium@8101:  * For the diagonal tracks the resulting track direction are clear for a given
rubidium@8101:  * DiagDirection. It either matches the direction or it returns INVALID_TRACKDIR,
rubidium@8101:  * as a TRACK_X cannot be applied with DIAG_SE.
rubidium@8101:  * For the straight tracks the resulting track direction will be the
rubidium@8101:  * direction which the DiagDirection is pointing. But this will be INVALID_TRACKDIR
rubidium@8101:  * if the DiagDirection is pointing 'away' the track.
rubidium@8101:  *
rubidium@8101:  * @param track The track to applie an direction on
rubidium@8101:  * @param diagdir The DiagDirection to applie on
rubidium@8101:  * @return The resulting track direction or INVALID_TRACKDIR if not possible.
rubidium@8101:  */
rubidium@8101: static inline Trackdir TrackExitdirToTrackdir(Track track, DiagDirection diagdir)
rubidium@8101: {
rubidium@8101: 	extern const Trackdir _track_exitdir_to_trackdir[TRACK_END][DIAGDIR_END];
rubidium@8101: 	return _track_exitdir_to_trackdir[track][diagdir];
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Maps a track and an (4-way) dir to the trackdir that represents the track
rubidium@8101:  * with the entry in the given direction.
rubidium@8101:  *
rubidium@8101:  * For the diagonal tracks the return value is clear, its either the matching
rubidium@8101:  * track direction or INVALID_TRACKDIR.
rubidium@8101:  * For the straight tracks this returns the track direction which results if
rubidium@8101:  * you follow the DiagDirection and then turn by 45 deg left or right on the
rubidium@8101:  * next tile. The new direction on the new track will be the returning Trackdir
rubidium@8101:  * value. If the parameters makes no sense like the track TRACK_UPPER and the
rubidium@8101:  * diraction DIAGDIR_NE (target track cannot be reached) this function returns
rubidium@8101:  * INVALID_TRACKDIR.
rubidium@8101:  *
rubidium@8101:  * @param track The target track
rubidium@8101:  * @param diagdir The direction to "come from"
rubidium@8101:  * @return the resulting Trackdir or INVALID_TRACKDIR if not possible.
rubidium@8101:  */
rubidium@8101: static inline Trackdir TrackEnterdirToTrackdir(Track track, DiagDirection diagdir)
rubidium@8101: {
rubidium@8101: 	extern const Trackdir _track_enterdir_to_trackdir[TRACK_END][DIAGDIR_END];
rubidium@8101: 	return _track_enterdir_to_trackdir[track][diagdir];
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Maps a track and a full (8-way) direction to the trackdir that represents
rubidium@8101:  * the track running in the given direction.
rubidium@8101:  */
rubidium@8101: static inline Trackdir TrackDirectionToTrackdir(Track track, Direction dir)
rubidium@8101: {
rubidium@8101: 	extern const Trackdir _track_direction_to_trackdir[TRACK_END][DIR_END];
rubidium@8101: 	return _track_direction_to_trackdir[track][dir];
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
smatz@9224:  * Maps a (4-way) direction to the diagonal track incidating with that diagdir
smatz@9224:  *
smatz@9224:  * @param diagdir The direction
smatz@9224:  * @return The resulting Track
smatz@9224:  */
smatz@9224: static inline Track DiagDirToDiagTrack(DiagDirection diagdir)
smatz@9224: {
smatz@9224: 	return (Track)(diagdir & 1);
smatz@9224: }
smatz@9224: 
smatz@9224: /**
smatz@9224:  * Maps a (4-way) direction to the diagonal track bits incidating with that diagdir
smatz@9224:  *
smatz@9224:  * @param diagdir The direction
smatz@9224:  * @return The resulting TrackBits
smatz@9224:  */
smatz@9224: static inline TrackBits DiagDirToDiagTrackBits(DiagDirection diagdir)
smatz@9224: {
smatz@9224: 	return TrackToTrackBits(DiagDirToDiagTrack(diagdir));
smatz@9224: }
smatz@9224: 
smatz@9224: /**
rubidium@8101:  * Maps a (4-way) direction to the diagonal trackdir that runs in that
rubidium@8101:  * direction.
rubidium@8101:  *
rubidium@8101:  * @param diagdir The direction
rubidium@8101:  * @return The resulting Trackdir direction
rubidium@8101:  */
smatz@9224: static inline Trackdir DiagDirToDiagTrackdir(DiagDirection diagdir)
rubidium@8101: {
rubidium@8101: 	extern const Trackdir _dir_to_diag_trackdir[DIAGDIR_END];
rubidium@8101: 	return _dir_to_diag_trackdir[diagdir];
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Returns all trackdirs that can be reached when entering a tile from a given
rubidium@8101:  * (diagonal) direction.
rubidium@8101:  *
rubidium@8101:  * This will obviously include 90 degree turns, since no information is available
rubidium@8101:  * about the exact angle of entering
rubidium@8101:  *
rubidium@8101:  * @param diagdir The joining direction
rubidium@8101:  * @return The TrackdirBits which can be used from the given direction
rubidium@8101:  * @see DiagdirReachesTracks
rubidium@8101:  */
rubidium@8101: static inline TrackdirBits DiagdirReachesTrackdirs(DiagDirection diagdir)
rubidium@8101: {
rubidium@8101: 	extern const TrackdirBits _exitdir_reaches_trackdirs[DIAGDIR_END];
rubidium@8101: 	return _exitdir_reaches_trackdirs[diagdir];
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Returns all tracks that can be reached when entering a tile from a given
rubidium@8101:  * (diagonal) direction.
rubidium@8101:  *
rubidium@8101:  * This will obviously include 90 degree turns, since no
rubidium@8101:  * information is available about the exact angle of entering
rubidium@8101:  *
rubidium@8101:  * @param diagdir The joining irection
rubidium@8101:  * @return The tracks which can be used
rubidium@8101:  * @see DiagdirReachesTrackdirs
rubidium@8101:  */
rubidium@8101: static inline TrackBits DiagdirReachesTracks(DiagDirection diagdir) { return TrackdirBitsToTrackBits(DiagdirReachesTrackdirs(diagdir)); }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Maps a trackdir to the trackdirs that can be reached from it (ie, when
rubidium@8101:  * entering the next tile.
rubidium@8101:  *
rubidium@8101:  * This will include 90 degree turns!
rubidium@8101:  *
rubidium@8101:  * @param trackdir The track direction which will be leaved
rubidium@8101:  * @return The track directions which can be used from this direction (in the next tile)
rubidium@8101:  */
rubidium@8101: static inline TrackdirBits TrackdirReachesTrackdirs(Trackdir trackdir)
rubidium@8101: {
rubidium@8101: 	extern const TrackdirBits _exitdir_reaches_trackdirs[DIAGDIR_END];
rubidium@8101: 	return _exitdir_reaches_trackdirs[TrackdirToExitdir(trackdir)];
rubidium@8101: }
rubidium@8101: /* Note that there is no direct table for this function (there used to be),
rubidium@8101:  * but it uses two simpeler tables to achieve the result */
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Maps a trackdir to all trackdirs that make 90 deg turns with it.
rubidium@8101:  *
rubidium@8101:  * For the diagonal tracks this returns the track direction bits
rubidium@8101:  * of the other axis in both directions, which cannot be joined by
rubidium@8101:  * the given track direction.
rubidium@8101:  * For the straight tracks this returns all possible 90 deg turns
rubidium@8101:  * either on the current tile (which no train can joined) or on the
rubidium@8101:  * bordering tiles.
rubidium@8101:  *
rubidium@8101:  * @param trackdir The track direction
rubidium@8101:  * @return The TrackdirBits which are (more or less) 90 deg turns.
rubidium@8101:  */
rubidium@8101: static inline TrackdirBits TrackdirCrossesTrackdirs(Trackdir trackdir)
rubidium@8101: {
rubidium@8101: 	extern const TrackdirBits _track_crosses_trackdirs[TRACKDIR_END];
rubidium@8101: 	return _track_crosses_trackdirs[TrackdirToTrack(trackdir)];
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Checks if a given Track is diagonal
rubidium@8101:  *
rubidium@8101:  * @param track The given track to check
rubidium@8101:  * @return true if diagonal, else false
rubidium@8101:  */
rubidium@8101: static inline bool IsDiagonalTrack(Track track)
rubidium@8101: {
rubidium@8101: 	return (track == TRACK_X) || (track == TRACK_Y);
rubidium@8101: }
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Checks if a given Trackdir is diagonal.
rubidium@8101:  *
rubidium@8101:  * @param trackdir The given trackdir
rubidium@8101:  * @return true if the trackdir use a diagonal track
rubidium@8101:  */
rubidium@8101: static inline bool IsDiagonalTrackdir(Trackdir trackdir)
rubidium@8101: {
rubidium@8101: 	return IsDiagonalTrack(TrackdirToTrack(trackdir));
rubidium@8101: }
rubidium@8101: 
rubidium@8101: 
rubidium@8101: /**
rubidium@8101:  * Checks if the given tracks overlap, ie form a crossing. Basically this
rubidium@8101:  * means when there is more than one track on the tile, exept when there are
rubidium@8101:  * two parallel tracks.
rubidium@8101:  * @param  bits The tracks present.
rubidium@8101:  * @return Whether the tracks present overlap in any way.
rubidium@8101:  */
rubidium@8101: static inline bool TracksOverlap(TrackBits bits)
rubidium@8101: {
rubidium@8101: 	/* With no, or only one track, there is no overlap */
rubidium@8101: 	if (bits == TRACK_BIT_NONE || KillFirstBit(bits) == TRACK_BIT_NONE) return false;
rubidium@8101: 	/* We know that there are at least two tracks present. When there are more
rubidium@8101: 	 * than 2 tracks, they will surely overlap. When there are two, they will
rubidium@8101: 	 * always overlap unless they are lower & upper or right & left. */
rubidium@8101: 	return bits != TRACK_BIT_HORZ && bits != TRACK_BIT_VERT;
rubidium@8101: }
rubidium@8101: 
rubidium@8102: /**
rubidium@8102:  * Checks whether the trackdir means that we are reversing.
rubidium@8102:  * @param dir the trackdir to check
rubidium@8102:  * @return true if it is a reversing road trackdir
rubidium@8102:  */
rubidium@8102: static inline bool IsReversingRoadTrackdir(Trackdir dir)
rubidium@8102: {
rubidium@8102: 	return (dir & 0x07) >= 6;
rubidium@8102: }
rubidium@8102: 
rubidium@8102: /**
rubidium@8102:  * Checks whether the given trackdir is a straight road
rubidium@8102:  * @param dir the trackdir to check
rubidium@8102:  * @return true if it is a straight road trackdir
rubidium@8102:  */
rubidium@8102: static inline bool IsStraightRoadTrackdir(Trackdir dir)
rubidium@8102: {
rubidium@8102: 	return (dir & 0x06) == 0;
rubidium@8102: }
rubidium@8102: 
frosch@8653: /**
frosch@8653:  * Checks whether a trackdir on a specific slope is going uphill.
frosch@8653:  *
frosch@8653:  * Valid for rail and road tracks.
frosch@8653:  * Valid for tile-slopes (under foundation) and foundation-slopes (on foundation).
frosch@8653:  *
frosch@8653:  * @param slope The slope of the tile.
frosch@8653:  * @param dir The trackdir of interest.
frosch@8653:  * @return true iff the track goes upwards.
frosch@8653:  */
frosch@8653: static inline bool IsUphillTrackdir(Slope slope, Trackdir dir)
frosch@8653: {
frosch@8653: 	extern const TrackdirBits _uphill_trackdirs[];
frosch@8653: 	return HasBit(_uphill_trackdirs[RemoveHalftileSlope(slope)], dir);
frosch@8653: }
frosch@8653: 
rubidium@8103: #endif /* TRACK_FUNC_H */