From df0c6eb2b9bfcdca6e220586340348ac3e3a00c5 Mon Sep 17 00:00:00 2001 From: rubidium Date: Tue, 18 Dec 2007 20:10:21 +0000 Subject: (svn r11662) -Codechange: move some rail types/related functions around. --- src/track_func.h | 497 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 497 insertions(+) create mode 100644 src/track_func.h (limited to 'src/track_func.h') diff --git a/src/track_func.h b/src/track_func.h new file mode 100644 index 000000000..32a872b61 --- /dev/null +++ b/src/track_func.h @@ -0,0 +1,497 @@ +/* $Id$ */ + +/** @file track_func.h Different conversion functions from one kind of track to another. */ + +#ifndef TRACK_FUNC_H +#define TRACK_FUNC_H + +#include "track_type.h" +#include "direction_type.h" + +/** + * Convert an Axis to the corresponding Track + * AXIS_X -> TRACK_X + * AXIS_Y -> TRACK_Y + * Uses the fact that they share the same internal encoding + * + * @param a the axis to convert + * @return the track corresponding to the axis + */ +static inline Track AxisToTrack(Axis a) +{ + return (Track)a; +} + + + +/** + * Maps a Track to the corresponding TrackBits value + * @param track the track to convert + * @return the converted TrackBits value of the track + */ +static inline TrackBits TrackToTrackBits(Track track) +{ + return (TrackBits)(1 << track); +} + +/** + * Maps an Axis to the corresponding TrackBits value + * @param a the axis to convert + * @return the converted TrackBits value of the axis + */ +static inline TrackBits AxisToTrackBits(Axis a) +{ + return TrackToTrackBits(AxisToTrack(a)); +} + +/** + * Returns a single horizontal/vertical trackbit, that is in a specific tile corner. + * + * @param corner The corner of a tile. + * @return The TrackBits of the track in the corner. + */ +static inline TrackBits CornerToTrackBits(Corner corner) +{ + extern const TrackBits _corner_to_trackbits[]; + assert(IsValidCorner(corner)); + return _corner_to_trackbits[corner]; +} + + + +/** + * Maps a Trackdir to the corresponding TrackdirBits value + * @param trackdir the track direction to convert + * @return the converted TrackdirBits value + */ +static inline TrackdirBits TrackdirToTrackdirBits(Trackdir trackdir) +{ + return (TrackdirBits)(1 << trackdir); +} + +/** + * Removes first Track from TrackBits and returns it + * + * This function searchs for the first bit in the TrackBits, + * remove this bit from the parameter and returns the found + * bit as Track value. It returns INVALID_TRACK if the + * parameter was TRACK_BIT_NONE or INVALID_TRACK_BIT. This + * is basically used in while-loops to get up to 6 possible + * tracks on a tile until the parameter becomes TRACK_BIT_NONE. + * + * @param tracks The value with the TrackBits + * @return The first Track from the TrackBits value + * @see FindFirstTrack + */ +static inline Track RemoveFirstTrack(TrackBits *tracks) +{ + if (*tracks != TRACK_BIT_NONE && *tracks != INVALID_TRACK_BIT) { + Track first = (Track)FIND_FIRST_BIT(*tracks); + ClrBit(*tracks, first); + return first; + } + return INVALID_TRACK; +} + +/** + * Removes first Trackdir from TrackdirBits and returns it + * + * This function searchs for the first bit in the TrackdirBits parameter, + * remove this bit from the parameter and returns the fnound bit as + * Trackdir value. It returns INVALID_TRACKDIR if the trackdirs is + * TRACKDIR_BIT_NONE or INVALID_TRACKDIR_BIT. This is basically used in a + * while-loop to get all track-directions step by step until the value + * reaches TRACKDIR_BIT_NONE. + * + * @param trackdirs The value with the TrackdirBits + * @return The first Trackdir from the TrackdirBits value + * @see FindFirstTrackdir + */ +static inline Trackdir RemoveFirstTrackdir(TrackdirBits *trackdirs) +{ + if (*trackdirs != TRACKDIR_BIT_NONE && *trackdirs != INVALID_TRACKDIR_BIT) { + Trackdir first = (Trackdir)FindFirstBit2x64(*trackdirs); + ClrBit(*trackdirs, first); + return first; + } + return INVALID_TRACKDIR; +} + +/** + * Returns first Track from TrackBits or INVALID_TRACK + * + * This function returns the first Track found in the TrackBits value as Track-value. + * It returns INVALID_TRACK if the parameter is TRACK_BIT_NONE or INVALID_TRACK_BIT. + * + * @param tracks The TrackBits value + * @return The first Track found or INVALID_TRACK + * @see RemoveFirstTrack + */ +static inline Track FindFirstTrack(TrackBits tracks) +{ + return (tracks != TRACK_BIT_NONE && tracks != INVALID_TRACK_BIT) ? (Track)FIND_FIRST_BIT(tracks) : INVALID_TRACK; +} + +/** + * Converts TrackBits to Track. + * + * This function converts a TrackBits value to a Track value. As it + * is not possible to convert two or more tracks to one track the + * parameter must contain only one track or be the INVALID_TRACK_BIT value. + * + * @param tracks The TrackBits value to convert + * @return The Track from the value or INVALID_TRACK + * @pre tracks must contains only one Track or be INVALID_TRACK_BIT + */ +static inline Track TrackBitsToTrack(TrackBits tracks) +{ + assert(tracks == INVALID_TRACK_BIT || (tracks != TRACK_BIT_NONE && KillFirstBit(tracks & TRACK_BIT_MASK) == TRACK_BIT_NONE)); + return tracks != INVALID_TRACK_BIT ? (Track)FIND_FIRST_BIT(tracks & TRACK_BIT_MASK) : INVALID_TRACK; +} + +/** + * Returns first Trackdir from TrackdirBits or INVALID_TRACKDIR + * + * This function returns the first Trackdir in the given TrackdirBits value or + * INVALID_TRACKDIR if the value is TRACKDIR_BIT_NONE. The TrackdirBits must + * not be INVALID_TRACKDIR_BIT. + * + * @param trackdirs The TrackdirBits value + * @return The first Trackdir from the TrackdirBits or INVALID_TRACKDIR on TRACKDIR_BIT_NONE. + * @pre trackdirs must not be INVALID_TRACKDIR_BIT + * @see RemoveFirstTrackdir + */ +static inline Trackdir FindFirstTrackdir(TrackdirBits trackdirs) +{ + assert((trackdirs & ~TRACKDIR_BIT_MASK) == TRACKDIR_BIT_NONE); + return (trackdirs != TRACKDIR_BIT_NONE) ? (Trackdir)FindFirstBit2x64(trackdirs) : INVALID_TRACKDIR; +} + +/** + * Checks if a Track is valid. + * + * @param track The value to check + * @return true if the given value is a valid track. + * @note Use this in an assert() + */ +static inline bool IsValidTrack(Track track) +{ + return track < TRACK_END; +} + +/** + * Checks if a Trackdir is valid. + * + * @param trackdir The value to check + * @return true if the given valie is a valid Trackdir + * @note Use this in an assert() + */ +static inline bool IsValidTrackdir(Trackdir trackdir) +{ + return (TrackdirToTrackdirBits(trackdir) & TRACKDIR_BIT_MASK) != 0; +} + + +/* + * Functions describing logical relations between Tracks, TrackBits, Trackdirs + * TrackdirBits, Direction and DiagDirections. + */ + +/** + * Maps a trackdir to the reverse trackdir. + * + * Returns the reverse trackdir of a Trackdir value. The reverse trackdir + * is the same track with the other direction on it. + * + * @param trackdir The Trackdir value + * @return The reverse trackdir + * @pre trackdir must not be INVALID_TRACKDIR + */ +static inline Trackdir ReverseTrackdir(Trackdir trackdir) +{ + assert(trackdir != INVALID_TRACKDIR); + return (Trackdir)(trackdir ^ 8); +} + +/** + * Returns the Track that a given Trackdir represents + * + * This function filters the Track which is used in the Trackdir value and + * returns it as a Track value. + * + * @param trackdir The trackdir value + * @return The Track which is used in the value + */ +static inline Track TrackdirToTrack(Trackdir trackdir) +{ + return (Track)(trackdir & 0x7); +} + +/** + * Returns a Trackdir for the given Track + * + * Since every Track corresponds to two Trackdirs, we choose the + * one which points between NE and S. Note that the actual + * implementation is quite futile, but this might change + * in the future. + * + * @param track The given Track + * @return The Trackdir from the given Track + */ +static inline Trackdir TrackToTrackdir(Track track) +{ + return (Trackdir)track; +} + +/** + * Returns a TrackdirBit mask from a given Track + * + * The TrackdirBit mask contains the two TrackdirBits that + * correspond with the given Track (one for each direction). + * + * @param track The track to get the TrackdirBits from + * @return The TrackdirBits which the selected tracks + */ +static inline TrackdirBits TrackToTrackdirBits(Track track) +{ + Trackdir td = TrackToTrackdir(track); + return (TrackdirBits)(TrackdirToTrackdirBits(td) | TrackdirToTrackdirBits(ReverseTrackdir(td))); +} + +/** + * Discards all directional information from a TrackdirBits value + * + * Any Track which is present in either direction will be present in the result. + * + * @param bits The TrackdirBits to get the TrackBits from + * @return The TrackBits + */ +static inline TrackBits TrackdirBitsToTrackBits(TrackdirBits bits) +{ + return (TrackBits)((bits | (bits >> 8)) & TRACK_BIT_MASK); +} + +/** + * Maps a trackdir to the trackdir that you will end up on if you go straight + * ahead. + * + * This will be the same trackdir for diagonal trackdirs, but a + * different (alternating) one for straight trackdirs + * + * @param trackdir The given trackdir + * @return The next Trackdir value of the next tile. + */ +static inline Trackdir NextTrackdir(Trackdir trackdir) +{ + extern const Trackdir _next_trackdir[TRACKDIR_END]; + return _next_trackdir[trackdir]; +} + +/** + * Maps a track to all tracks that make 90 deg turns with it. + * + * For the diagonal directions these are the complement of the + * direction, for the straight directions these are the + * two vertical or horizontal tracks, depend on the given direction + * + * @param track The given track + * @return The TrackBits with the tracks marked which cross the given track by 90 deg. + */ +static inline TrackBits TrackCrossesTracks(Track track) +{ + extern const TrackBits _track_crosses_tracks[TRACK_END]; + return _track_crosses_tracks[track]; +} + +/** + * Maps a trackdir to the (4-way) direction the tile is exited when following + * that trackdir. + * + * For the diagonal directions these are the same directions. For + * the straight directions these are the directions from the imagined + * base-tile to the bordering tile which will be joined if the given + * straight direction is leaved from the base-tile. + * + * @param trackdir The given track direction + * @return The direction which points to the resulting tile if following the Trackdir + */ +static inline DiagDirection TrackdirToExitdir(Trackdir trackdir) +{ + extern const DiagDirection _trackdir_to_exitdir[TRACKDIR_END]; + return _trackdir_to_exitdir[trackdir]; +} + +/** + * Maps a track and an (4-way) dir to the trackdir that represents the track + * with the exit in the given direction. + * + * For the diagonal tracks the resulting track direction are clear for a given + * DiagDirection. It either matches the direction or it returns INVALID_TRACKDIR, + * as a TRACK_X cannot be applied with DIAG_SE. + * For the straight tracks the resulting track direction will be the + * direction which the DiagDirection is pointing. But this will be INVALID_TRACKDIR + * if the DiagDirection is pointing 'away' the track. + * + * @param track The track to applie an direction on + * @param diagdir The DiagDirection to applie on + * @return The resulting track direction or INVALID_TRACKDIR if not possible. + */ +static inline Trackdir TrackExitdirToTrackdir(Track track, DiagDirection diagdir) +{ + extern const Trackdir _track_exitdir_to_trackdir[TRACK_END][DIAGDIR_END]; + return _track_exitdir_to_trackdir[track][diagdir]; +} + +/** + * Maps a track and an (4-way) dir to the trackdir that represents the track + * with the entry in the given direction. + * + * For the diagonal tracks the return value is clear, its either the matching + * track direction or INVALID_TRACKDIR. + * For the straight tracks this returns the track direction which results if + * you follow the DiagDirection and then turn by 45 deg left or right on the + * next tile. The new direction on the new track will be the returning Trackdir + * value. If the parameters makes no sense like the track TRACK_UPPER and the + * diraction DIAGDIR_NE (target track cannot be reached) this function returns + * INVALID_TRACKDIR. + * + * @param track The target track + * @param diagdir The direction to "come from" + * @return the resulting Trackdir or INVALID_TRACKDIR if not possible. + */ +static inline Trackdir TrackEnterdirToTrackdir(Track track, DiagDirection diagdir) +{ + extern const Trackdir _track_enterdir_to_trackdir[TRACK_END][DIAGDIR_END]; + return _track_enterdir_to_trackdir[track][diagdir]; +} + +/** + * Maps a track and a full (8-way) direction to the trackdir that represents + * the track running in the given direction. + */ +static inline Trackdir TrackDirectionToTrackdir(Track track, Direction dir) +{ + extern const Trackdir _track_direction_to_trackdir[TRACK_END][DIR_END]; + return _track_direction_to_trackdir[track][dir]; +} + +/** + * Maps a (4-way) direction to the diagonal trackdir that runs in that + * direction. + * + * @param diagdir The direction + * @return The resulting Trackdir direction + */ +static inline Trackdir DiagdirToDiagTrackdir(DiagDirection diagdir) +{ + extern const Trackdir _dir_to_diag_trackdir[DIAGDIR_END]; + return _dir_to_diag_trackdir[diagdir]; +} + +/** + * Returns all trackdirs that can be reached when entering a tile from a given + * (diagonal) direction. + * + * This will obviously include 90 degree turns, since no information is available + * about the exact angle of entering + * + * @param diagdir The joining direction + * @return The TrackdirBits which can be used from the given direction + * @see DiagdirReachesTracks + */ +static inline TrackdirBits DiagdirReachesTrackdirs(DiagDirection diagdir) +{ + extern const TrackdirBits _exitdir_reaches_trackdirs[DIAGDIR_END]; + return _exitdir_reaches_trackdirs[diagdir]; +} + +/** + * Returns all tracks that can be reached when entering a tile from a given + * (diagonal) direction. + * + * This will obviously include 90 degree turns, since no + * information is available about the exact angle of entering + * + * @param diagdir The joining irection + * @return The tracks which can be used + * @see DiagdirReachesTrackdirs + */ +static inline TrackBits DiagdirReachesTracks(DiagDirection diagdir) { return TrackdirBitsToTrackBits(DiagdirReachesTrackdirs(diagdir)); } + +/** + * Maps a trackdir to the trackdirs that can be reached from it (ie, when + * entering the next tile. + * + * This will include 90 degree turns! + * + * @param trackdir The track direction which will be leaved + * @return The track directions which can be used from this direction (in the next tile) + */ +static inline TrackdirBits TrackdirReachesTrackdirs(Trackdir trackdir) +{ + extern const TrackdirBits _exitdir_reaches_trackdirs[DIAGDIR_END]; + return _exitdir_reaches_trackdirs[TrackdirToExitdir(trackdir)]; +} +/* Note that there is no direct table for this function (there used to be), + * but it uses two simpeler tables to achieve the result */ + +/** + * Maps a trackdir to all trackdirs that make 90 deg turns with it. + * + * For the diagonal tracks this returns the track direction bits + * of the other axis in both directions, which cannot be joined by + * the given track direction. + * For the straight tracks this returns all possible 90 deg turns + * either on the current tile (which no train can joined) or on the + * bordering tiles. + * + * @param trackdir The track direction + * @return The TrackdirBits which are (more or less) 90 deg turns. + */ +static inline TrackdirBits TrackdirCrossesTrackdirs(Trackdir trackdir) +{ + extern const TrackdirBits _track_crosses_trackdirs[TRACKDIR_END]; + return _track_crosses_trackdirs[TrackdirToTrack(trackdir)]; +} + +/** + * Checks if a given Track is diagonal + * + * @param track The given track to check + * @return true if diagonal, else false + */ +static inline bool IsDiagonalTrack(Track track) +{ + return (track == TRACK_X) || (track == TRACK_Y); +} + +/** + * Checks if a given Trackdir is diagonal. + * + * @param trackdir The given trackdir + * @return true if the trackdir use a diagonal track + */ +static inline bool IsDiagonalTrackdir(Trackdir trackdir) +{ + return IsDiagonalTrack(TrackdirToTrack(trackdir)); +} + + +/** + * Checks if the given tracks overlap, ie form a crossing. Basically this + * means when there is more than one track on the tile, exept when there are + * two parallel tracks. + * @param bits The tracks present. + * @return Whether the tracks present overlap in any way. + */ +static inline bool TracksOverlap(TrackBits bits) +{ + /* With no, or only one track, there is no overlap */ + if (bits == TRACK_BIT_NONE || KillFirstBit(bits) == TRACK_BIT_NONE) return false; + /* We know that there are at least two tracks present. When there are more + * than 2 tracks, they will surely overlap. When there are two, they will + * always overlap unless they are lower & upper or right & left. */ + return bits != TRACK_BIT_HORZ && bits != TRACK_BIT_VERT; +} + +#endif /* RAIL_H */ -- cgit v1.2.3-54-g00ecf