# pbs.cpp

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    00001 /* $Id: pbs.cpp 20168 2010-07-17 11:45:42Z rubidium $ */
    00002
    00003 /*
    00004  * This file is part of OpenTTD.
    00005  * 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.
    00006  * 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.
    00007  * 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/>.
    00008  */
    00009
    00012 #include "stdafx.h"
    00013 #include "functions.h"
    00014 #include "vehicle_func.h"
    00015 #include "pathfinder/follow_track.hpp"
    00016
    00023 TrackBits GetReservedTrackbits(TileIndex t)
    00024 {
    00025   switch (GetTileType(t)) {
    00026     case MP_RAILWAY:
    00027       if (IsRailDepot(t)) return GetDepotReservationTrackBits(t);
    00028       if (IsPlainRail(t)) return GetRailReservationTrackBits(t);
    00029       break;
    00030
    00031     case MP_ROAD:
    00032       if (IsLevelCrossing(t)) return GetCrossingReservationTrackBits(t);
    00033       break;
    00034
    00035     case MP_STATION:
    00036       if (HasStationRail(t)) return GetStationReservationTrackBits(t);
    00037       break;
    00038
    00039     case MP_TUNNELBRIDGE:
    00040       if (GetTunnelBridgeTransportType(t) == TRANSPORT_RAIL) return GetTunnelBridgeReservationTrackBits(t);
    00041       break;
    00042
    00043     default:
    00044       break;
    00045   }
    00046   return TRACK_BIT_NONE;
    00047 }
    00048
    00056 void SetRailStationPlatformReservation(TileIndex start, DiagDirection dir, bool b)
    00057 {
    00058   TileIndex     tile = start;
    00059   TileIndexDiff diff = TileOffsByDiagDir(dir);
    00060
    00061   assert(IsRailStationTile(start));
    00062   assert(GetRailStationAxis(start) == DiagDirToAxis(dir));
    00063
    00064   do {
    00065     SetRailStationReservation(tile, b);
    00066     MarkTileDirtyByTile(tile);
    00067     tile = TILE_ADD(tile, diff);
    00068   } while (IsCompatibleTrainStationTile(tile, start));
    00069 }
    00070
    00078 bool TryReserveRailTrack(TileIndex tile, Track t)
    00079 {
    00080   assert((GetTileTrackStatus(tile, TRANSPORT_RAIL, 0) & TrackToTrackBits(t)) != 0);
    00081
    00082   if (_settings_client.gui.show_track_reservation) {
    00083     /* show the reserved rail if needed */
    00084     MarkTileDirtyByTile(tile);
    00085   }
    00086
    00087   switch (GetTileType(tile)) {
    00088     case MP_RAILWAY:
    00089       if (IsPlainRail(tile)) return TryReserveTrack(tile, t);
    00090       if (IsRailDepot(tile)) {
    00091         if (!HasDepotReservation(tile)) {
    00092           SetDepotReservation(tile, true);
    00093           MarkTileDirtyByTile(tile); // some GRFs change their appearance when tile is reserved
    00094           return true;
    00095         }
    00096       }
    00097       break;
    00098
    00099     case MP_ROAD:
    00100       if (IsLevelCrossing(tile) && !HasCrossingReservation(tile)) {
    00101         SetCrossingReservation(tile, true);
    00102         BarCrossing(tile);
    00103         MarkTileDirtyByTile(tile); // crossing barred, make tile dirty
    00104         return true;
    00105       }
    00106       break;
    00107
    00108     case MP_STATION:
    00109       if (HasStationRail(tile) && !HasStationReservation(tile)) {
    00110         SetRailStationReservation(tile, true);
    00111         MarkTileDirtyByTile(tile); // some GRFs need redraw after reserving track
    00112         return true;
    00113       }
    00114       break;
    00115
    00116     case MP_TUNNELBRIDGE:
    00117       if (GetTunnelBridgeTransportType(tile) == TRANSPORT_RAIL && !GetTunnelBridgeReservationTrackBits(tile)) {
    00118         SetTunnelBridgeReservation(tile, true);
    00119         return true;
    00120       }
    00121       break;
    00122
    00123     default:
    00124       break;
    00125   }
    00126   return false;
    00127 }
    00128
    00134 void UnreserveRailTrack(TileIndex tile, Track t)
    00135 {
    00136   assert((GetTileTrackStatus(tile, TRANSPORT_RAIL, 0) & TrackToTrackBits(t)) != 0);
    00137
    00138   if (_settings_client.gui.show_track_reservation) {
    00139     MarkTileDirtyByTile(tile);
    00140   }
    00141
    00142   switch (GetTileType(tile)) {
    00143     case MP_RAILWAY:
    00144       if (IsRailDepot(tile)) {
    00145         SetDepotReservation(tile, false);
    00146         MarkTileDirtyByTile(tile);
    00147         break;
    00148       }
    00149       if (IsPlainRail(tile)) UnreserveTrack(tile, t);
    00150       break;
    00151
    00152     case MP_ROAD:
    00153       if (IsLevelCrossing(tile)) {
    00154         SetCrossingReservation(tile, false);
    00155         UpdateLevelCrossing(tile);
    00156       }
    00157       break;
    00158
    00159     case MP_STATION:
    00160       if (HasStationRail(tile)) {
    00161         SetRailStationReservation(tile, false);
    00162         MarkTileDirtyByTile(tile);
    00163       }
    00164       break;
    00165
    00166     case MP_TUNNELBRIDGE:
    00167       if (GetTunnelBridgeTransportType(tile) == TRANSPORT_RAIL) SetTunnelBridgeReservation(tile, false);
    00168       break;
    00169
    00170     default:
    00171       break;
    00172   }
    00173 }
    00174
    00175
    00177 static PBSTileInfo FollowReservation(Owner o, RailTypes rts, TileIndex tile, Trackdir trackdir, bool ignore_oneway = false)
    00178 {
    00179   TileIndex start_tile = tile;
    00180   Trackdir  start_trackdir = trackdir;
    00181   bool      first_loop = true;
    00182
    00183   /* Start track not reserved? This can happen if two trains
    00184    * are on the same tile. The reservation on the next tile
    00185    * is not ours in this case, so exit. */
    00186   if (!HasReservedTracks(tile, TrackToTrackBits(TrackdirToTrack(trackdir)))) return PBSTileInfo(tile, trackdir, false);
    00187
    00188   /* Do not disallow 90 deg turns as the setting might have changed between reserving and now. */
    00189   CFollowTrackRail ft(o, rts);
    00190   while (ft.Follow(tile, trackdir)) {
    00191     TrackdirBits reserved = ft.m_new_td_bits & TrackBitsToTrackdirBits(GetReservedTrackbits(ft.m_new_tile));
    00192
    00193     /* No reservation --> path end found */
    00194     if (reserved == TRACKDIR_BIT_NONE) break;
    00195
    00196     /* Can't have more than one reserved trackdir */
    00197     Trackdir new_trackdir = FindFirstTrackdir(reserved);
    00198
    00199     /* One-way signal against us. The reservation can't be ours as it is not
    00200      * a safe position from our direction and we can never pass the signal. */
    00201     if (!ignore_oneway && HasOnewaySignalBlockingTrackdir(ft.m_new_tile, new_trackdir)) break;
    00202
    00203     tile = ft.m_new_tile;
    00204     trackdir = new_trackdir;
    00205
    00206     if (first_loop) {
    00207       /* Update the start tile after we followed the track the first
    00208        * time. This is neccessary because the track follower can skip
    00209        * tiles (in stations for example) which means that we might
    00210        * never visit our original starting tile again. */
    00211       start_tile = tile;
    00212       start_trackdir = trackdir;
    00213       first_loop = false;
    00214     } else {
    00215       /* Loop encountered? */
    00216       if (tile == start_tile && trackdir == start_trackdir) break;
    00217     }
    00218     /* Depot tile? Can't continue. */
    00219     if (IsRailDepotTile(tile)) break;
    00220     /* Non-pbs signal? Reservation can't continue. */
    00221     if (IsTileType(tile, MP_RAILWAY) && HasSignalOnTrackdir(tile, trackdir) && !IsPbsSignal(GetSignalType(tile, TrackdirToTrack(trackdir)))) break;
    00222   }
    00223
    00224   return PBSTileInfo(tile, trackdir, false);
    00225 }
    00226
    00230 struct FindTrainOnTrackInfo {
    00231   PBSTileInfo res;
    00232   Train *best;
    00233
    00235   FindTrainOnTrackInfo() : best(NULL) {}
    00236 };
    00237
    00239 static Vehicle *FindTrainOnTrackEnum(Vehicle *v, void *data)
    00240 {
    00241   FindTrainOnTrackInfo *info = (FindTrainOnTrackInfo *)data;
    00242
    00243   if (v->type != VEH_TRAIN || (v->vehstatus & VS_CRASHED)) return NULL;
    00244
    00245   Train *t = Train::From(v);
    00246   if (t->track == TRACK_BIT_WORMHOLE || HasBit((TrackBits)t->track, TrackdirToTrack(info->res.trackdir))) {
    00247     t = t->First();
    00248
    00249     /* ALWAYS return the lowest ID (anti-desync!) */
    00250     if (info->best == NULL || t->index < info->best->index) info->best = t;
    00251     return t;
    00252   }
    00253
    00254   return NULL;
    00255 }
    00256
    00264 PBSTileInfo FollowTrainReservation(const Train *v, Vehicle **train_on_res)
    00265 {
    00266   assert(v->type == VEH_TRAIN);
    00267
    00268   TileIndex tile = v->tile;
    00269   Trackdir  trackdir = v->GetVehicleTrackdir();
    00270
    00271   if (IsRailDepotTile(tile) && !GetDepotReservationTrackBits(tile)) return PBSTileInfo(tile, trackdir, false);
    00272
    00273   FindTrainOnTrackInfo ftoti;
    00274   ftoti.res = FollowReservation(v->owner, GetRailTypeInfo(v->railtype)->compatible_railtypes, tile, trackdir);
    00275   ftoti.res.okay = IsSafeWaitingPosition(v, ftoti.res.tile, ftoti.res.trackdir, true, _settings_game.pf.forbid_90_deg);
    00276   if (train_on_res != NULL) {
    00277     FindVehicleOnPos(ftoti.res.tile, &ftoti, FindTrainOnTrackEnum);
    00278     if (ftoti.best != NULL) *train_on_res = ftoti.best->First();
    00279     if (*train_on_res == NULL && IsRailStationTile(ftoti.res.tile)) {
    00280       /* The target tile is a rail station. The track follower
    00281        * has stopped on the last platform tile where we haven't
    00282        * found a train. Also check all previous platform tiles
    00283        * for a possible train. */
    00284       TileIndexDiff diff = TileOffsByDiagDir(TrackdirToExitdir(ReverseTrackdir(ftoti.res.trackdir)));
    00285       for (TileIndex st_tile = ftoti.res.tile + diff; *train_on_res == NULL && IsCompatibleTrainStationTile(st_tile, ftoti.res.tile); st_tile += diff) {
    00286         FindVehicleOnPos(st_tile, &ftoti, FindTrainOnTrackEnum);
    00287         if (ftoti.best != NULL) *train_on_res = ftoti.best->First();
    00288       }
    00289     }
    00290     if (*train_on_res == NULL && IsTileType(ftoti.res.tile, MP_TUNNELBRIDGE)) {
    00291       /* The target tile is a bridge/tunnel, also check the other end tile. */
    00292       FindVehicleOnPos(GetOtherTunnelBridgeEnd(ftoti.res.tile), &ftoti, FindTrainOnTrackEnum);
    00293       if (ftoti.best != NULL) *train_on_res = ftoti.best->First();
    00294     }
    00295   }
    00296   return ftoti.res;
    00297 }
    00298
    00306 Train *GetTrainForReservation(TileIndex tile, Track track)
    00307 {
    00308   assert(HasReservedTracks(tile, TrackToTrackBits(track)));
    00309   Trackdir  trackdir = TrackToTrackdir(track);
    00310
    00311   RailTypes rts = GetRailTypeInfo(GetTileRailType(tile))->compatible_railtypes;
    00312
    00313   /* Follow the path from tile to both ends, one of the end tiles should
    00314    * have a train on it. We need FollowReservation to ignore one-way signals
    00315    * here, as one of the two search directions will be the "wrong" way. */
    00316   for (int i = 0; i < 2; ++i, trackdir = ReverseTrackdir(trackdir)) {
    00317     /* If the tile has a one-way block signal in the current trackdir, skip the
    00318      * search in this direction as the reservation can't come from this side.*/
    00319     if (HasOnewaySignalBlockingTrackdir(tile, ReverseTrackdir(trackdir)) && !HasPbsSignalOnTrackdir(tile, trackdir)) continue;
    00320
    00321     FindTrainOnTrackInfo ftoti;
    00322     ftoti.res = FollowReservation(GetTileOwner(tile), rts, tile, trackdir, true);
    00323
    00324     FindVehicleOnPos(ftoti.res.tile, &ftoti, FindTrainOnTrackEnum);
    00325     if (ftoti.best != NULL) return ftoti.best;
    00326
    00327     /* Special case for stations: check the whole platform for a vehicle. */
    00328     if (IsRailStationTile(ftoti.res.tile)) {
    00329       TileIndexDiff diff = TileOffsByDiagDir(TrackdirToExitdir(ReverseTrackdir(ftoti.res.trackdir)));
    00330       for (TileIndex st_tile = ftoti.res.tile + diff; IsCompatibleTrainStationTile(st_tile, ftoti.res.tile); st_tile += diff) {
    00331         FindVehicleOnPos(st_tile, &ftoti, FindTrainOnTrackEnum);
    00332         if (ftoti.best != NULL) return ftoti.best;
    00333       }
    00334     }
    00335
    00336     /* Special case for bridges/tunnels: check the other end as well. */
    00337     if (IsTileType(ftoti.res.tile, MP_TUNNELBRIDGE)) {
    00338       FindVehicleOnPos(GetOtherTunnelBridgeEnd(ftoti.res.tile), &ftoti, FindTrainOnTrackEnum);
    00339       if (ftoti.best != NULL) return ftoti.best;
    00340     }
    00341   }
    00342
    00343   return NULL;
    00344 }
    00345
    00356 bool IsSafeWaitingPosition(const Train *v, TileIndex tile, Trackdir trackdir, bool include_line_end, bool forbid_90deg)
    00357 {
    00358   if (IsRailDepotTile(tile)) return true;
    00359
    00360   if (IsTileType(tile, MP_RAILWAY)) {
    00361     /* For non-pbs signals, stop on the signal tile. */
    00362     if (HasSignalOnTrackdir(tile, trackdir) && !IsPbsSignal(GetSignalType(tile, TrackdirToTrack(trackdir)))) return true;
    00363   }
    00364
    00365   /* Check next tile. For perfomance reasons, we check for 90 degree turns ourself. */
    00366   CFollowTrackRail ft(v, GetRailTypeInfo(v->railtype)->compatible_railtypes);
    00367
    00368   /* End of track? */
    00369   if (!ft.Follow(tile, trackdir)) {
    00370     /* Last tile of a terminus station is a safe position. */
    00371     if (include_line_end) return true;
    00372   }
    00373
    00374   /* Check for reachable tracks. */
    00375   ft.m_new_td_bits &= DiagdirReachesTrackdirs(ft.m_exitdir);
    00376   if (forbid_90deg) ft.m_new_td_bits &= ~TrackdirCrossesTrackdirs(trackdir);
    00377   if (ft.m_new_td_bits == TRACKDIR_BIT_NONE) return include_line_end;
    00378
    00379   if (ft.m_new_td_bits != TRACKDIR_BIT_NONE && KillFirstBit(ft.m_new_td_bits) == TRACKDIR_BIT_NONE) {
    00380     Trackdir td = FindFirstTrackdir(ft.m_new_td_bits);
    00381     /* PBS signal on next trackdir? Safe position. */
    00382     if (HasPbsSignalOnTrackdir(ft.m_new_tile, td)) return true;
    00383     /* One-way PBS signal against us? Safe if end-of-line is allowed. */
    00384     if (IsTileType(ft.m_new_tile, MP_RAILWAY) && HasSignalOnTrackdir(ft.m_new_tile, ReverseTrackdir(td)) &&
    00385         GetSignalType(ft.m_new_tile, TrackdirToTrack(td)) == SIGTYPE_PBS_ONEWAY) {
    00386       return include_line_end;
    00387     }
    00388   }
    00389
    00390   return false;
    00391 }
    00392
    00402 bool IsWaitingPositionFree(const Train *v, TileIndex tile, Trackdir trackdir, bool forbid_90deg)
    00403 {
    00404   Track     track = TrackdirToTrack(trackdir);
    00405   TrackBits reserved = GetReservedTrackbits(tile);
    00406
    00407   /* Tile reserved? Can never be a free waiting position. */
    00408   if (TrackOverlapsTracks(reserved, track)) return false;
    00409
    00410   /* Not reserved and depot or not a pbs signal -> free. */
    00411   if (IsRailDepotTile(tile)) return true;
    00412   if (IsTileType(tile, MP_RAILWAY) && HasSignalOnTrackdir(tile, trackdir) && !IsPbsSignal(GetSignalType(tile, track))) return true;
    00413
    00414   /* Check the next tile, if it's a PBS signal, it has to be free as well. */
    00415   CFollowTrackRail ft(v, GetRailTypeInfo(v->railtype)->compatible_railtypes);
    00416
    00417   if (!ft.Follow(tile, trackdir)) return true;
    00418
    00419   /* Check for reachable tracks. */
    00420   ft.m_new_td_bits &= DiagdirReachesTrackdirs(ft.m_exitdir);
    00421   if (forbid_90deg) ft.m_new_td_bits &= ~TrackdirCrossesTrackdirs(trackdir);
    00422
    00423   return !HasReservedTracks(ft.m_new_tile, TrackdirBitsToTrackBits(ft.m_new_td_bits));
    00424 }