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|
/* $Id$ */
/*
* 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 track_func.h Different conversion functions from one kind of track to another. */
#ifndef TRACK_FUNC_H
#define TRACK_FUNC_H
#include "core/bitmath_func.hpp"
#include "track_type.h"
#include "direction_func.h"
#include "slope_func.h"
/**
* Iterate through each set Track in a TrackBits value.
* For more informations see FOR_EACH_SET_BIT_EX.
*
* @param var Loop index variable that stores fallowing set track. Must be of type Track.
* @param track_bits The value to iterate through (any expression).
*
* @see FOR_EACH_SET_BIT_EX
*/
#define FOR_EACH_SET_TRACK(var, track_bits) FOR_EACH_SET_BIT_EX(Track, var, TrackBits, track_bits)
/**
* 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 for road vehicles.
*
* @param trackdir The value to check
* @return true if the given value is a valid Trackdir
* @note Use this in an assert()
*/
static inline bool IsValidTrackdirForRoadVehicle(Trackdir trackdir)
{
return trackdir < TRACKDIR_END;
}
/**
* Checks if a Trackdir is valid for non-road vehicles.
*
* @param trackdir The value to check
* @return true if the given value is a valid Trackdir
* @note Use this in an assert()
*/
static inline bool IsValidTrackdir(Trackdir trackdir)
{
return (1 << trackdir & TRACKDIR_BIT_MASK) != TRACKDIR_BIT_NONE;
}
/**
* 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)
{
assert(IsValidAxis(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)
{
assert(IsValidTrack(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)
{
assert(IsValidTrackdir(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) {
assert((*tracks & ~TRACK_BIT_MASK) == TRACK_BIT_NONE);
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 searches 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) {
assert((*trackdirs & ~TRACKDIR_BIT_MASK) == TRACKDIR_BIT_NONE);
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;
}
/*
* Functions describing logical relations between Tracks, TrackBits, Trackdirs
* TrackdirBits, Direction and DiagDirections.
*/
/**
* Find the opposite track to a given track.
*
* TRACK_LOWER -> TRACK_UPPER and vice versa, likewise for left/right.
* TRACK_X is mapped to TRACK_Y and reversed.
*
* @param t the track to convert
* @return the opposite track
*/
static inline Track TrackToOppositeTrack(Track t)
{
assert(IsValidTrack(t));
return (Track)(t ^ 1);
}
/**
* 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(IsValidTrackdirForRoadVehicle(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)
{
assert(IsValidTrackdir(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)
{
assert(IsValidTrack(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);
}
/**
* Converts TrackBits to TrackdirBits while allowing both directions.
*
* @param bits The TrackBits
* @return The TrackdirBits containing of bits in both directions.
*/
static inline TrackdirBits TrackBitsToTrackdirBits(TrackBits bits)
{
return (TrackdirBits)(bits * 0x101);
}
/**
* Returns the present-trackdir-information of a TrackStatus.
*
* @param ts The TrackStatus returned by GetTileTrackStatus()
* @return the present trackdirs
*/
static inline TrackdirBits TrackStatusToTrackdirBits(TrackStatus ts)
{
return (TrackdirBits)(ts & TRACKDIR_BIT_MASK);
}
/**
* Returns the present-track-information of a TrackStatus.
*
* @param ts The TrackStatus returned by GetTileTrackStatus()
* @return the present tracks
*/
static inline TrackBits TrackStatusToTrackBits(TrackStatus ts)
{
return TrackdirBitsToTrackBits(TrackStatusToTrackdirBits(ts));
}
/**
* Returns the red-signal-information of a TrackStatus.
*
* Note: The result may contain red signals for non-present tracks.
*
* @param ts The TrackStatus returned by GetTileTrackStatus()
* @return the The trackdirs that are blocked by red-signals
*/
static inline TrackdirBits TrackStatusToRedSignals(TrackStatus ts)
{
return (TrackdirBits)((ts >> 16) & TRACKDIR_BIT_MASK);
}
/**
* Builds a TrackStatus
*
* @param trackdirbits present trackdirs
* @param red_signals red signals
* @return the TrackStatus representing the given information
*/
static inline TrackStatus CombineTrackStatus(TrackdirBits trackdirbits, TrackdirBits red_signals)
{
return (TrackStatus)(trackdirbits | (red_signals << 16));
}
/**
* 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)
{
assert(IsValidTrackdir(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)
{
assert(IsValidTrack(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)
{
assert(IsValidTrackdirForRoadVehicle(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 apply an direction on
* @param diagdir The DiagDirection to apply on
* @return The resulting track direction or INVALID_TRACKDIR if not possible.
*/
static inline Trackdir TrackExitdirToTrackdir(Track track, DiagDirection diagdir)
{
assert(IsValidTrack(track));
assert(IsValidDiagDirection(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
* direction 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)
{
assert(IsValidTrack(track));
assert(IsValidDiagDirection(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)
{
assert(IsValidTrack(track));
assert(IsValidDirection(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 track incidating with that diagdir
*
* @param diagdir The direction
* @return The resulting Track
*/
static inline Track DiagDirToDiagTrack(DiagDirection diagdir)
{
assert(IsValidDiagDirection(diagdir));
return (Track)(diagdir & 1);
}
/**
* Maps a (4-way) direction to the diagonal track bits incidating with that diagdir
*
* @param diagdir The direction
* @return The resulting TrackBits
*/
static inline TrackBits DiagDirToDiagTrackBits(DiagDirection diagdir)
{
assert(IsValidDiagDirection(diagdir));
return TrackToTrackBits(DiagDirToDiagTrack(diagdir));
}
/**
* 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)
{
assert(IsValidDiagDirection(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)
{
assert(IsValidDiagDirection(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 direction
* @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)
{
assert(IsValidTrackdir(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 simpler 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)
{
assert(IsValidTrackdirForRoadVehicle(trackdir));
extern const TrackdirBits _track_crosses_trackdirs[TRACK_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)
{
assert(IsValidTrack(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)
{
assert(IsValidTrackdir(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;
}
/**
* Check if a given track is contained within or overlaps some other tracks.
*
* @param tracks Tracks to be tested against
* @param track The track to test
* @return true if the track is already in the tracks or overlaps the tracks.
*/
static inline bool TrackOverlapsTracks(TrackBits tracks, Track track)
{
if (HasBit(tracks, track)) return true;
return TracksOverlap(tracks | TrackToTrackBits(track));
}
/**
* Checks whether the trackdir means that we are reversing.
* @param dir the trackdir to check
* @return true if it is a reversing road trackdir
*/
static inline bool IsReversingRoadTrackdir(Trackdir dir)
{
assert(IsValidTrackdirForRoadVehicle(dir));
return (dir & 0x07) >= 6;
}
/**
* Checks whether the given trackdir is a straight road
* @param dir the trackdir to check
* @return true if it is a straight road trackdir
*/
static inline bool IsStraightRoadTrackdir(Trackdir dir)
{
assert(IsValidTrackdirForRoadVehicle(dir));
return (dir & 0x06) == 0;
}
/**
* Checks whether a trackdir on a specific slope is going uphill.
*
* Valid for rail and road tracks.
* Valid for tile-slopes (under foundation) and foundation-slopes (on foundation).
*
* @param slope The slope of the tile.
* @param dir The trackdir of interest.
* @return true iff the track goes upwards.
*/
static inline bool IsUphillTrackdir(Slope slope, Trackdir dir)
{
assert(IsValidTrackdirForRoadVehicle(dir));
extern const TrackdirBits _uphill_trackdirs[];
return HasBit(_uphill_trackdirs[RemoveHalftileSlope(slope)], dir);
}
/**
* Determine the side in which the vehicle will leave the tile
*
* @param direction vehicle direction
* @param track vehicle track bits
* @return side of tile the vehicle will leave
*/
static inline DiagDirection VehicleExitDir(Direction direction, TrackBits track)
{
static const TrackBits state_dir_table[DIAGDIR_END] = { TRACK_BIT_RIGHT, TRACK_BIT_LOWER, TRACK_BIT_LEFT, TRACK_BIT_UPPER };
DiagDirection diagdir = DirToDiagDir(direction);
/* Determine the diagonal direction in which we will exit this tile */
if (!HasBit(direction, 0) && track != state_dir_table[diagdir]) {
diagdir = ChangeDiagDir(diagdir, DIAGDIRDIFF_90LEFT);
}
return diagdir;
}
#endif /* TRACK_FUNC_H */
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