pbs.cpp

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00001 /* $Id: pbs.cpp 18809 2010-01-15 16:41:15Z 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   }
00291   return ftoti.res;
00292 }
00293 
00301 Train *GetTrainForReservation(TileIndex tile, Track track)
00302 {
00303   assert(HasReservedTracks(tile, TrackToTrackBits(track)));
00304   Trackdir  trackdir = TrackToTrackdir(track);
00305 
00306   RailTypes rts = GetRailTypeInfo(GetTileRailType(tile))->compatible_railtypes;
00307 
00308   /* Follow the path from tile to both ends, one of the end tiles should
00309    * have a train on it. We need FollowReservation to ignore one-way signals
00310    * here, as one of the two search directions will be the "wrong" way. */
00311   for (int i = 0; i < 2; ++i, trackdir = ReverseTrackdir(trackdir)) {
00312     FindTrainOnTrackInfo ftoti;
00313     ftoti.res = FollowReservation(GetTileOwner(tile), rts, tile, trackdir, true);
00314 
00315     FindVehicleOnPos(ftoti.res.tile, &ftoti, FindTrainOnTrackEnum);
00316     if (ftoti.best != NULL) return ftoti.best;
00317 
00318     /* Special case for stations: check the whole platform for a vehicle. */
00319     if (IsRailStationTile(ftoti.res.tile)) {
00320       TileIndexDiff diff = TileOffsByDiagDir(TrackdirToExitdir(ReverseTrackdir(ftoti.res.trackdir)));
00321       for (TileIndex st_tile = ftoti.res.tile + diff; IsCompatibleTrainStationTile(st_tile, ftoti.res.tile); st_tile += diff) {
00322         FindVehicleOnPos(st_tile, &ftoti, FindTrainOnTrackEnum);
00323         if (ftoti.best != NULL) return ftoti.best;
00324       }
00325     }
00326 
00327     /* Special case for bridges/tunnels: check the other end as well. */
00328     if (IsTileType(ftoti.res.tile, MP_TUNNELBRIDGE)) {
00329       FindVehicleOnPos(GetOtherTunnelBridgeEnd(ftoti.res.tile), &ftoti, FindTrainOnTrackEnum);
00330       if (ftoti.best != NULL) return ftoti.best;
00331     }
00332   }
00333 
00334   return NULL;
00335 }
00336 
00347 bool IsSafeWaitingPosition(const Train *v, TileIndex tile, Trackdir trackdir, bool include_line_end, bool forbid_90deg)
00348 {
00349   if (IsRailDepotTile(tile)) return true;
00350 
00351   if (IsTileType(tile, MP_RAILWAY)) {
00352     /* For non-pbs signals, stop on the signal tile. */
00353     if (HasSignalOnTrackdir(tile, trackdir) && !IsPbsSignal(GetSignalType(tile, TrackdirToTrack(trackdir)))) return true;
00354   }
00355 
00356   /* Check next tile. For perfomance reasons, we check for 90 degree turns ourself. */
00357   CFollowTrackRail ft(v, GetRailTypeInfo(v->railtype)->compatible_railtypes);
00358 
00359   /* End of track? */
00360   if (!ft.Follow(tile, trackdir)) {
00361     /* Last tile of a terminus station is a safe position. */
00362     if (include_line_end) return true;
00363   }
00364 
00365   /* Check for reachable tracks. */
00366   ft.m_new_td_bits &= DiagdirReachesTrackdirs(ft.m_exitdir);
00367   if (forbid_90deg) ft.m_new_td_bits &= ~TrackdirCrossesTrackdirs(trackdir);
00368   if (ft.m_new_td_bits == TRACKDIR_BIT_NONE) return include_line_end;
00369 
00370   if (ft.m_new_td_bits != TRACKDIR_BIT_NONE && KillFirstBit(ft.m_new_td_bits) == TRACKDIR_BIT_NONE) {
00371     Trackdir td = FindFirstTrackdir(ft.m_new_td_bits);
00372     /* PBS signal on next trackdir? Safe position. */
00373     if (HasPbsSignalOnTrackdir(ft.m_new_tile, td)) return true;
00374     /* One-way PBS signal against us? Safe if end-of-line is allowed. */
00375     if (IsTileType(ft.m_new_tile, MP_RAILWAY) && HasSignalOnTrackdir(ft.m_new_tile, ReverseTrackdir(td)) &&
00376         GetSignalType(ft.m_new_tile, TrackdirToTrack(td)) == SIGTYPE_PBS_ONEWAY) {
00377       return include_line_end;
00378     }
00379   }
00380 
00381   return false;
00382 }
00383 
00393 bool IsWaitingPositionFree(const Train *v, TileIndex tile, Trackdir trackdir, bool forbid_90deg)
00394 {
00395   Track     track = TrackdirToTrack(trackdir);
00396   TrackBits reserved = GetReservedTrackbits(tile);
00397 
00398   /* Tile reserved? Can never be a free waiting position. */
00399   if (TrackOverlapsTracks(reserved, track)) return false;
00400 
00401   /* Not reserved and depot or not a pbs signal -> free. */
00402   if (IsRailDepotTile(tile)) return true;
00403   if (IsTileType(tile, MP_RAILWAY) && HasSignalOnTrackdir(tile, trackdir) && !IsPbsSignal(GetSignalType(tile, track))) return true;
00404 
00405   /* Check the next tile, if it's a PBS signal, it has to be free as well. */
00406   CFollowTrackRail ft(v, GetRailTypeInfo(v->railtype)->compatible_railtypes);
00407 
00408   if (!ft.Follow(tile, trackdir)) return true;
00409 
00410   /* Check for reachable tracks. */
00411   ft.m_new_td_bits &= DiagdirReachesTrackdirs(ft.m_exitdir);
00412   if (forbid_90deg) ft.m_new_td_bits &= ~TrackdirCrossesTrackdirs(trackdir);
00413 
00414   return !HasReservedTracks(ft.m_new_tile, TrackdirBitsToTrackBits(ft.m_new_td_bits));
00415 }

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