659 lines
20 KiB
C
659 lines
20 KiB
C
/* $Id$ */
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/*
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* This file is part of OpenTTD.
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* 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.
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* 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.
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* 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/>.
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*/
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/** @file track_func.h Different conversion functions from one kind of track to another. */
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#ifndef TRACK_FUNC_H
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#define TRACK_FUNC_H
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#include "core/bitmath_func.hpp"
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#include "track_type.h"
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#include "slope_func.h"
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/**
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* Iterate through each set Track in a TrackBits value.
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* For more informations see FOR_EACH_SET_BIT_EX.
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*
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* @param var Loop index variable that stores fallowing set track. Must be of type Track.
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* @param track_bits The value to iterate through (any expression).
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*
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* @see FOR_EACH_SET_BIT_EX
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*/
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#define FOR_EACH_SET_TRACK(var, track_bits) FOR_EACH_SET_BIT_EX(Track, var, TrackBits, track_bits)
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/**
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* Convert an Axis to the corresponding Track
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* AXIS_X -> TRACK_X
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* AXIS_Y -> TRACK_Y
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* Uses the fact that they share the same internal encoding
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*
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* @param a the axis to convert
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* @return the track corresponding to the axis
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*/
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static inline Track AxisToTrack(Axis a)
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{
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return (Track)a;
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}
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/**
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* Maps a Track to the corresponding TrackBits value
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* @param track the track to convert
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* @return the converted TrackBits value of the track
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*/
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static inline TrackBits TrackToTrackBits(Track track)
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{
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return (TrackBits)(1 << track);
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}
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/**
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* Maps an Axis to the corresponding TrackBits value
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* @param a the axis to convert
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* @return the converted TrackBits value of the axis
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*/
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static inline TrackBits AxisToTrackBits(Axis a)
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{
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return TrackToTrackBits(AxisToTrack(a));
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}
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/**
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* Returns a single horizontal/vertical trackbit that is in a specific tile corner.
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*
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* @param corner The corner of a tile.
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* @return The TrackBits of the track in the corner.
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*/
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static inline TrackBits CornerToTrackBits(Corner corner)
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{
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extern const TrackBits _corner_to_trackbits[];
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assert(IsValidCorner(corner));
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return _corner_to_trackbits[corner];
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}
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/**
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* Maps a Trackdir to the corresponding TrackdirBits value
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* @param trackdir the track direction to convert
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* @return the converted TrackdirBits value
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*/
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static inline TrackdirBits TrackdirToTrackdirBits(Trackdir trackdir)
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{
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return (TrackdirBits)(1 << trackdir);
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}
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/**
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* Removes first Track from TrackBits and returns it
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*
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* This function searchs for the first bit in the TrackBits,
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* remove this bit from the parameter and returns the found
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* bit as Track value. It returns INVALID_TRACK if the
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* parameter was TRACK_BIT_NONE or INVALID_TRACK_BIT. This
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* is basically used in while-loops to get up to 6 possible
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* tracks on a tile until the parameter becomes TRACK_BIT_NONE.
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*
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* @param tracks The value with the TrackBits
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* @return The first Track from the TrackBits value
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* @see FindFirstTrack
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*/
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static inline Track RemoveFirstTrack(TrackBits *tracks)
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{
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if (*tracks != TRACK_BIT_NONE && *tracks != INVALID_TRACK_BIT) {
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Track first = (Track)FIND_FIRST_BIT(*tracks);
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ClrBit(*tracks, first);
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return first;
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}
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return INVALID_TRACK;
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}
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/**
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* Removes first Trackdir from TrackdirBits and returns it
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*
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* This function searchs for the first bit in the TrackdirBits parameter,
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* remove this bit from the parameter and returns the fnound bit as
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* Trackdir value. It returns INVALID_TRACKDIR if the trackdirs is
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* TRACKDIR_BIT_NONE or INVALID_TRACKDIR_BIT. This is basically used in a
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* while-loop to get all track-directions step by step until the value
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* reaches TRACKDIR_BIT_NONE.
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*
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* @param trackdirs The value with the TrackdirBits
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* @return The first Trackdir from the TrackdirBits value
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* @see FindFirstTrackdir
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*/
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static inline Trackdir RemoveFirstTrackdir(TrackdirBits *trackdirs)
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{
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if (*trackdirs != TRACKDIR_BIT_NONE && *trackdirs != INVALID_TRACKDIR_BIT) {
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Trackdir first = (Trackdir)FindFirstBit2x64(*trackdirs);
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ClrBit(*trackdirs, first);
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return first;
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}
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return INVALID_TRACKDIR;
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}
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/**
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* Returns first Track from TrackBits or INVALID_TRACK
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*
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* This function returns the first Track found in the TrackBits value as Track-value.
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* It returns INVALID_TRACK if the parameter is TRACK_BIT_NONE or INVALID_TRACK_BIT.
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*
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* @param tracks The TrackBits value
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* @return The first Track found or INVALID_TRACK
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* @see RemoveFirstTrack
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*/
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static inline Track FindFirstTrack(TrackBits tracks)
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{
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return (tracks != TRACK_BIT_NONE && tracks != INVALID_TRACK_BIT) ? (Track)FIND_FIRST_BIT(tracks) : INVALID_TRACK;
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}
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/**
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* Converts TrackBits to Track.
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*
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* This function converts a TrackBits value to a Track value. As it
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* is not possible to convert two or more tracks to one track the
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* parameter must contain only one track or be the INVALID_TRACK_BIT value.
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*
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* @param tracks The TrackBits value to convert
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* @return The Track from the value or INVALID_TRACK
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* @pre tracks must contains only one Track or be INVALID_TRACK_BIT
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*/
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static inline Track TrackBitsToTrack(TrackBits tracks)
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{
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assert(tracks == INVALID_TRACK_BIT || (tracks != TRACK_BIT_NONE && KillFirstBit(tracks & TRACK_BIT_MASK) == TRACK_BIT_NONE));
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return tracks != INVALID_TRACK_BIT ? (Track)FIND_FIRST_BIT(tracks & TRACK_BIT_MASK) : INVALID_TRACK;
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}
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/**
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* Returns first Trackdir from TrackdirBits or INVALID_TRACKDIR
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*
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* This function returns the first Trackdir in the given TrackdirBits value or
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* INVALID_TRACKDIR if the value is TRACKDIR_BIT_NONE. The TrackdirBits must
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* not be INVALID_TRACKDIR_BIT.
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*
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* @param trackdirs The TrackdirBits value
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* @return The first Trackdir from the TrackdirBits or INVALID_TRACKDIR on TRACKDIR_BIT_NONE.
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* @pre trackdirs must not be INVALID_TRACKDIR_BIT
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* @see RemoveFirstTrackdir
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*/
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static inline Trackdir FindFirstTrackdir(TrackdirBits trackdirs)
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{
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assert((trackdirs & ~TRACKDIR_BIT_MASK) == TRACKDIR_BIT_NONE);
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return (trackdirs != TRACKDIR_BIT_NONE) ? (Trackdir)FindFirstBit2x64(trackdirs) : INVALID_TRACKDIR;
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}
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/**
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* Checks if a Track is valid.
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*
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* @param track The value to check
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* @return true if the given value is a valid track.
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* @note Use this in an assert()
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*/
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static inline bool IsValidTrack(Track track)
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{
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return track < TRACK_END;
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}
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/**
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* Checks if a Trackdir is valid.
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*
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* @param trackdir The value to check
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* @return true if the given valie is a valid Trackdir
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* @note Use this in an assert()
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*/
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static inline bool IsValidTrackdir(Trackdir trackdir)
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{
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return (TrackdirToTrackdirBits(trackdir) & TRACKDIR_BIT_MASK) != 0;
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}
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/*
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* Functions describing logical relations between Tracks, TrackBits, Trackdirs
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* TrackdirBits, Direction and DiagDirections.
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*/
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/**
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* Find the opposite track to a given track.
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*
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* TRACK_LOWER -> TRACK_UPPER and vice versa, likewise for left/right.
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* TRACK_X is mapped to TRACK_Y and reversed.
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*
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* @param t the track to convert
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* @return the opposite track
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*/
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static inline Track TrackToOppositeTrack(Track t)
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{
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assert(t != INVALID_TRACK);
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return (Track)(t ^ 1);
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}
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/**
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* Maps a trackdir to the reverse trackdir.
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*
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* Returns the reverse trackdir of a Trackdir value. The reverse trackdir
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* is the same track with the other direction on it.
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*
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* @param trackdir The Trackdir value
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* @return The reverse trackdir
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* @pre trackdir must not be INVALID_TRACKDIR
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*/
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static inline Trackdir ReverseTrackdir(Trackdir trackdir)
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{
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assert(trackdir != INVALID_TRACKDIR);
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return (Trackdir)(trackdir ^ 8);
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}
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/**
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* Returns the Track that a given Trackdir represents
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*
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* This function filters the Track which is used in the Trackdir value and
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* returns it as a Track value.
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*
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* @param trackdir The trackdir value
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* @return The Track which is used in the value
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*/
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static inline Track TrackdirToTrack(Trackdir trackdir)
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{
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return (Track)(trackdir & 0x7);
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}
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/**
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* Returns a Trackdir for the given Track
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*
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* Since every Track corresponds to two Trackdirs, we choose the
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* one which points between NE and S. Note that the actual
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* implementation is quite futile, but this might change
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* in the future.
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*
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* @param track The given Track
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* @return The Trackdir from the given Track
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*/
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static inline Trackdir TrackToTrackdir(Track track)
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{
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return (Trackdir)track;
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}
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/**
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* Returns a TrackdirBit mask from a given Track
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*
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* The TrackdirBit mask contains the two TrackdirBits that
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* correspond with the given Track (one for each direction).
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*
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* @param track The track to get the TrackdirBits from
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* @return The TrackdirBits which the selected tracks
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*/
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static inline TrackdirBits TrackToTrackdirBits(Track track)
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{
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Trackdir td = TrackToTrackdir(track);
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return (TrackdirBits)(TrackdirToTrackdirBits(td) | TrackdirToTrackdirBits(ReverseTrackdir(td)));
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}
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/**
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* Discards all directional information from a TrackdirBits value
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*
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* Any Track which is present in either direction will be present in the result.
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*
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* @param bits The TrackdirBits to get the TrackBits from
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* @return The TrackBits
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*/
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static inline TrackBits TrackdirBitsToTrackBits(TrackdirBits bits)
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{
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return (TrackBits)((bits | (bits >> 8)) & TRACK_BIT_MASK);
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}
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/**
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* Converts TrackBits to TrackdirBits while allowing both directions.
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*
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* @param bits The TrackBits
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* @return The TrackdirBits containing of bits in both directions.
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*/
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static inline TrackdirBits TrackBitsToTrackdirBits(TrackBits bits)
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{
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return (TrackdirBits)(bits * 0x101);
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}
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/**
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* Returns the present-trackdir-information of a TrackStatus.
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*
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* @param ts The TrackStatus returned by GetTileTrackStatus()
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* @return the present trackdirs
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*/
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static inline TrackdirBits TrackStatusToTrackdirBits(TrackStatus ts)
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{
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return (TrackdirBits)(ts & TRACKDIR_BIT_MASK);
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}
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/**
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* Returns the present-track-information of a TrackStatus.
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*
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* @param ts The TrackStatus returned by GetTileTrackStatus()
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* @return the present tracks
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*/
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static inline TrackBits TrackStatusToTrackBits(TrackStatus ts)
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{
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return TrackdirBitsToTrackBits(TrackStatusToTrackdirBits(ts));
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}
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/**
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* Returns the red-signal-information of a TrackStatus.
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*
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* Note: The result may contain red signals for non-present tracks.
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*
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* @param ts The TrackStatus returned by GetTileTrackStatus()
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* @return the The trackdirs that are blocked by red-signals
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*/
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static inline TrackdirBits TrackStatusToRedSignals(TrackStatus ts)
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{
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return (TrackdirBits)((ts >> 16) & TRACKDIR_BIT_MASK);
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}
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/**
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* Builds a TrackStatus
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*
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* @param trackdirbits present trackdirs
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* @param red_signals red signals
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* @return the TrackStatus representing the given information
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*/
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static inline TrackStatus CombineTrackStatus(TrackdirBits trackdirbits, TrackdirBits red_signals)
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{
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return (TrackStatus)(trackdirbits | (red_signals << 16));
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}
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/**
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* Maps a trackdir to the trackdir that you will end up on if you go straight
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* ahead.
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*
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* This will be the same trackdir for diagonal trackdirs, but a
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* different (alternating) one for straight trackdirs
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*
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* @param trackdir The given trackdir
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* @return The next Trackdir value of the next tile.
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*/
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static inline Trackdir NextTrackdir(Trackdir trackdir)
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{
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extern const Trackdir _next_trackdir[TRACKDIR_END];
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return _next_trackdir[trackdir];
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}
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/**
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* Maps a track to all tracks that make 90 deg turns with it.
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*
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* For the diagonal directions these are the complement of the
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* direction, for the straight directions these are the
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* two vertical or horizontal tracks, depend on the given direction
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*
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* @param track The given track
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* @return The TrackBits with the tracks marked which cross the given track by 90 deg.
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*/
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static inline TrackBits TrackCrossesTracks(Track track)
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{
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extern const TrackBits _track_crosses_tracks[TRACK_END];
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return _track_crosses_tracks[track];
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}
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/**
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* Maps a trackdir to the (4-way) direction the tile is exited when following
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* that trackdir.
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*
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* For the diagonal directions these are the same directions. For
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* the straight directions these are the directions from the imagined
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* base-tile to the bordering tile which will be joined if the given
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* straight direction is leaved from the base-tile.
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*
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* @param trackdir The given track direction
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* @return The direction which points to the resulting tile if following the Trackdir
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*/
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static inline DiagDirection TrackdirToExitdir(Trackdir trackdir)
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{
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extern const DiagDirection _trackdir_to_exitdir[TRACKDIR_END];
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return _trackdir_to_exitdir[trackdir];
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}
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/**
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* Maps a track and an (4-way) dir to the trackdir that represents the track
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* with the exit in the given direction.
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*
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* For the diagonal tracks the resulting track direction are clear for a given
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* DiagDirection. It either matches the direction or it returns INVALID_TRACKDIR,
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* as a TRACK_X cannot be applied with DIAG_SE.
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* For the straight tracks the resulting track direction will be the
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* direction which the DiagDirection is pointing. But this will be INVALID_TRACKDIR
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* if the DiagDirection is pointing 'away' the track.
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*
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* @param track The track to applie an direction on
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* @param diagdir The DiagDirection to applie on
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* @return The resulting track direction or INVALID_TRACKDIR if not possible.
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*/
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static inline Trackdir TrackExitdirToTrackdir(Track track, DiagDirection diagdir)
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{
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extern const Trackdir _track_exitdir_to_trackdir[TRACK_END][DIAGDIR_END];
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return _track_exitdir_to_trackdir[track][diagdir];
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}
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/**
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* Maps a track and an (4-way) dir to the trackdir that represents the track
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* with the entry in the given direction.
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*
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* For the diagonal tracks the return value is clear, its either the matching
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* track direction or INVALID_TRACKDIR.
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* For the straight tracks this returns the track direction which results if
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* you follow the DiagDirection and then turn by 45 deg left or right on the
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* next tile. The new direction on the new track will be the returning Trackdir
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* value. If the parameters makes no sense like the track TRACK_UPPER and the
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* diraction DIAGDIR_NE (target track cannot be reached) this function returns
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* INVALID_TRACKDIR.
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*
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* @param track The target track
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* @param diagdir The direction to "come from"
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* @return the resulting Trackdir or INVALID_TRACKDIR if not possible.
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*/
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static inline Trackdir TrackEnterdirToTrackdir(Track track, DiagDirection diagdir)
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{
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extern const Trackdir _track_enterdir_to_trackdir[TRACK_END][DIAGDIR_END];
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return _track_enterdir_to_trackdir[track][diagdir];
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}
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/**
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* Maps a track and a full (8-way) direction to the trackdir that represents
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* the track running in the given direction.
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*/
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static inline Trackdir TrackDirectionToTrackdir(Track track, Direction dir)
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{
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extern const Trackdir _track_direction_to_trackdir[TRACK_END][DIR_END];
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return _track_direction_to_trackdir[track][dir];
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}
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/**
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* Maps a (4-way) direction to the diagonal track incidating with that diagdir
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*
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* @param diagdir The direction
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* @return The resulting Track
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*/
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static inline Track DiagDirToDiagTrack(DiagDirection diagdir)
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{
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return (Track)(diagdir & 1);
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}
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/**
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* Maps a (4-way) direction to the diagonal track bits incidating with that diagdir
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*
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* @param diagdir The direction
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* @return The resulting TrackBits
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*/
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static inline TrackBits DiagDirToDiagTrackBits(DiagDirection diagdir)
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{
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return TrackToTrackBits(DiagDirToDiagTrack(diagdir));
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}
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/**
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* Maps a (4-way) direction to the diagonal trackdir that runs in that
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* direction.
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*
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* @param diagdir The direction
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* @return The resulting Trackdir direction
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*/
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static inline Trackdir DiagDirToDiagTrackdir(DiagDirection diagdir)
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{
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extern const Trackdir _dir_to_diag_trackdir[DIAGDIR_END];
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return _dir_to_diag_trackdir[diagdir];
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}
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/**
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* Returns all trackdirs that can be reached when entering a tile from a given
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* (diagonal) direction.
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*
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* This will obviously include 90 degree turns, since no information is available
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* about the exact angle of entering
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*
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* @param diagdir The joining direction
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* @return The TrackdirBits which can be used from the given direction
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* @see DiagdirReachesTracks
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*/
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static inline TrackdirBits DiagdirReachesTrackdirs(DiagDirection diagdir)
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{
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extern const TrackdirBits _exitdir_reaches_trackdirs[DIAGDIR_END];
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return _exitdir_reaches_trackdirs[diagdir];
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}
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|
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|
/**
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|
* Returns all tracks that can be reached when entering a tile from a given
|
|
* (diagonal) direction.
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|
*
|
|
* 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
|
|
*/
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|
static inline TrackBits DiagdirReachesTracks(DiagDirection diagdir) { return TrackdirBitsToTrackBits(DiagdirReachesTrackdirs(diagdir)); }
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|
|
|
/**
|
|
* 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)
|
|
*/
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|
static inline TrackdirBits TrackdirReachesTrackdirs(Trackdir trackdir)
|
|
{
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|
extern const TrackdirBits _exitdir_reaches_trackdirs[DIAGDIR_END];
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|
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;
|
|
}
|
|
|
|
/**
|
|
* Check if a given track is contained within or overlaps some other tracks.
|
|
*
|
|
* @param tracks Tracks to be testet 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)
|
|
{
|
|
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)
|
|
{
|
|
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)
|
|
{
|
|
extern const TrackdirBits _uphill_trackdirs[];
|
|
return HasBit(_uphill_trackdirs[RemoveHalftileSlope(slope)], dir);
|
|
}
|
|
|
|
#endif /* TRACK_FUNC_H */
|