src/pbs.cpp

   1 /* $Id$ */
   2
   3 /*
   4  * This file is part of OpenTTD.
   5  * 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.
   6  * 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.
   7  * 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/>.
   8  */
   9
  10 /** @file pbs.cpp PBS support routines */
  11
  12 #include "stdafx.h"
  13 #include "viewport_func.h"
  14 #include "vehicle_func.h"
  15 #include "newgrf_station.h"
  16 #include "pathfinder/follow_track.hpp"
  17
  18 /**
  19  * Get the reserved trackbits for any tile, regardless of type.
  20  * @param t the tile
  21  * @return the reserved trackbits. TRACK_BIT_NONE on nothing reserved or
  22  *     a tile without rail.
  23  */
  24 TrackBits GetReservedTrackbits(TileIndex t)
  25 {
  26         switch (GetTileType(t)) {
  27                 case MP_RAILWAY:
  28                         if (IsRailDepot(t)) return GetDepotReservationTrackBits(t);
  29                         if (IsPlainRail(t)) return GetRailReservationTrackBits(t);
  30                         break;
  31
  32                 case MP_ROAD:
  33                         if (IsLevelCrossing(t)) return GetCrossingReservationTrackBits(t);
  34                         break;
  35
  36                 case MP_STATION:
  37                         if (HasStationRail(t)) return GetStationReservationTrackBits(t);
  38                         break;
  39
  40                 case MP_TUNNELBRIDGE:
  41                         if (GetTunnelBridgeTransportType(t) == TRANSPORT_RAIL) return GetTunnelBridgeReservationTrackBits(t);
  42                         break;
  43
  44                 default:
  45                         break;
  46         }
  47         return TRACK_BIT_NONE;
  48 }
  49
  50 /**
  51  * Set the reservation for a complete station platform.
  52  * @pre IsRailStationTile(start)
  53  * @param start starting tile of the platform
  54  * @param dir the direction in which to follow the platform
  55  * @param b the state the reservation should be set to
  56  */
  57 void SetRailStationPlatformReservation(TileIndex start, DiagDirection dir, bool b)
  58 {
  59         TileIndex     tile = start;
  60         TileIndexDiff diff = TileOffsByDiagDir(dir);
  61
  62         assert(IsRailStationTile(start));
  63         assert(GetRailStationAxis(start) == DiagDirToAxis(dir));
  64
  65         do {
  66                 SetRailStationReservation(tile, b);
  67                 MarkTileDirtyByTile(tile);
  68                 tile = TILE_ADD(tile, diff);
  69         } while (IsCompatibleTrainStationTile(tile, start));
  70 }
  71
  72 /**
  73  * Try to reserve a specific track on a tile
  74  * @param tile the tile
  75  * @param t the track
  76  * @param trigger_stations whether to call station randomisation trigger
  77  * @return \c true if reservation was successful, i.e. the track was
  78  *     free and didn't cross any other reserved tracks.
  79  */
  80 bool TryReserveRailTrack(TileIndex tile, Track t, bool trigger_stations)
  81 {
  82         assert((GetTileTrackStatus(tile, TRANSPORT_RAIL, 0) & TrackToTrackBits(t)) != 0);
  83
  84         if (_settings_client.gui.show_track_reservation) {
  85                 /* show the reserved rail if needed */
  86                 MarkTileDirtyByTile(tile);
  87         }
  88
  89         switch (GetTileType(tile)) {
  90                 case MP_RAILWAY:
  91                         if (IsPlainRail(tile)) return TryReserveTrack(tile, t);
  92                         if (IsRailDepot(tile)) {
  93                                 if (!HasDepotReservation(tile)) {
  94                                         SetDepotReservation(tile, true);
  95                                         MarkTileDirtyByTile(tile); // some GRFs change their appearance when tile is reserved
  96                                         return true;
  97                                 }
  98                         }
  99                         break;
 100
 101                 case MP_ROAD:
 102                         if (IsLevelCrossing(tile) && !HasCrossingReservation(tile)) {
 103                                 SetCrossingReservation(tile, true);
 104                                 BarCrossing(tile);
 105                                 MarkTileDirtyByTile(tile); // crossing barred, make tile dirty
 106                                 return true;
 107                         }
 108                         break;
 109
 110                 case MP_STATION:
 111                         if (HasStationRail(tile) && !HasStationReservation(tile)) {
 112                                 SetRailStationReservation(tile, true);
 113                                 if (trigger_stations && IsRailStation(tile)) TriggerStationRandomisation(NULL, tile, SRT_PATH_RESERVATION);
 114                                 MarkTileDirtyByTile(tile); // some GRFs need redraw after reserving track
 115                                 return true;
 116                         }
 117                         break;
 118
 119                 case MP_TUNNELBRIDGE:
 120                         if (GetTunnelBridgeTransportType(tile) == TRANSPORT_RAIL && !GetTunnelBridgeReservationTrackBits(tile)) {
 121                                 SetTunnelBridgeReservation(tile, true);
 122                                 return true;
 123                         }
 124                         break;
 125
 126                 default:
 127                         break;
 128         }
 129         return false;
 130 }
 131
 132 /**
 133  * Lift the reservation of a specific track on a tile
 134  * @param tile the tile
 135  * @param t the track
 136  */
 137 void UnreserveRailTrack(TileIndex tile, Track t)
 138 {
 139         assert((GetTileTrackStatus(tile, TRANSPORT_RAIL, 0) & TrackToTrackBits(t)) != 0);
 140
 141         if (_settings_client.gui.show_track_reservation) {
 142                 MarkTileDirtyByTile(tile);
 143         }
 144
 145         switch (GetTileType(tile)) {
 146                 case MP_RAILWAY:
 147                         if (IsRailDepot(tile)) {
 148                                 SetDepotReservation(tile, false);
 149                                 MarkTileDirtyByTile(tile);
 150                                 break;
 151                         }
 152                         if (IsPlainRail(tile)) UnreserveTrack(tile, t);
 153                         break;
 154
 155                 case MP_ROAD:
 156                         if (IsLevelCrossing(tile)) {
 157                                 SetCrossingReservation(tile, false);
 158                                 UpdateLevelCrossing(tile);
 159                         }
 160                         break;
 161
 162                 case MP_STATION:
 163                         if (HasStationRail(tile)) {
 164                                 SetRailStationReservation(tile, false);
 165                                 MarkTileDirtyByTile(tile);
 166                         }
 167                         break;
 168
 169                 case MP_TUNNELBRIDGE:
 170                         if (GetTunnelBridgeTransportType(tile) == TRANSPORT_RAIL) SetTunnelBridgeReservation(tile, false);
 171                         break;
 172
 173                 default:
 174                         break;
 175         }
 176 }
 177
 178
 179 /** Follow a reservation starting from a specific tile to the end. */
 180 static PBSTileInfo FollowReservation(Owner o, RailTypes rts, TileIndex tile, Trackdir trackdir, bool ignore_oneway = false)
 181 {
 182         TileIndex start_tile = tile;
 183         Trackdir  start_trackdir = trackdir;
 184         bool      first_loop = true;
 185
 186         /* Start track not reserved? This can happen if two trains
 187          * are on the same tile. The reservation on the next tile
 188          * is not ours in this case, so exit. */
 189         if (!HasReservedTracks(tile, TrackToTrackBits(TrackdirToTrack(trackdir)))) return PBSTileInfo(tile, trackdir, false);
 190
 191         /* Do not disallow 90 deg turns as the setting might have changed between reserving and now. */
 192         CFollowTrackRail ft(o, rts);
 193         while (ft.Follow(tile, trackdir)) {
 194                 TrackdirBits reserved = ft.m_new_td_bits & TrackBitsToTrackdirBits(GetReservedTrackbits(ft.m_new_tile));
 195
 196                 /* No reservation --> path end found */
 197                 if (reserved == TRACKDIR_BIT_NONE) {
 198                         if (ft.m_is_station) {
 199                                 /* Check skipped station tiles as well, maybe our reservation ends inside the station. */
 200                                 TileIndexDiff diff = TileOffsByDiagDir(ft.m_exitdir);
 201                                 while (ft.m_tiles_skipped-- > 0) {
 202                                         ft.m_new_tile -= diff;
 203                                         if (HasStationReservation(ft.m_new_tile)) {
 204                                                 tile = ft.m_new_tile;
 205                                                 trackdir = DiagDirToDiagTrackdir(ft.m_exitdir);
 206                                                 break;
 207                                         }
 208                                 }
 209                         }
 210                         break;
 211                 }
 212
 213                 /* Can't have more than one reserved trackdir */
 214                 Trackdir new_trackdir = FindFirstTrackdir(reserved);
 215
 216                 /* One-way signal against us. The reservation can't be ours as it is not
 217                  * a safe position from our direction and we can never pass the signal. */
 218                 if (!ignore_oneway && HasOnewaySignalBlockingTrackdir(ft.m_new_tile, new_trackdir)) break;
 219
 220                 tile = ft.m_new_tile;
 221                 trackdir = new_trackdir;
 222
 223                 if (first_loop) {
 224                         /* Update the start tile after we followed the track the first
 225                          * time. This is necessary because the track follower can skip
 226                          * tiles (in stations for example) which means that we might
 227                          * never visit our original starting tile again. */
 228                         start_tile = tile;
 229                         start_trackdir = trackdir;
 230                         first_loop = false;
 231                 } else {
 232                         /* Loop encountered? */
 233                         if (tile == start_tile && trackdir == start_trackdir) break;
 234                 }
 235                 /* Depot tile? Can't continue. */
 236                 if (IsRailDepotTile(tile)) break;
 237                 /* Non-pbs signal? Reservation can't continue. */
 238                 if (IsTileType(tile, MP_RAILWAY) && HasSignalOnTrackdir(tile, trackdir) && !IsPbsSignal(GetSignalType(tile, TrackdirToTrack(trackdir)))) break;
 239         }
 240
 241         return PBSTileInfo(tile, trackdir, false);
 242 }
 243
 244 /**
 245  * Helper struct for finding the best matching vehicle on a specific track.
 246  */
 247 struct FindTrainOnTrackInfo {
 248         PBSTileInfo res; ///< Information about the track.
 249         Train *best;     ///< The currently "best" vehicle we have found.
 250
 251         /** Init the best location to NULL always! */
 252         FindTrainOnTrackInfo() : best(NULL) {}
 253 };
 254
 255 /** Callback for Has/FindVehicleOnPos to find a train on a specific track. */
 256 static Vehicle *FindTrainOnTrackEnum(Vehicle *v, void *data)
 257 {
 258         FindTrainOnTrackInfo *info = (FindTrainOnTrackInfo *)data;
 259
 260         if (v->type != VEH_TRAIN || (v->vehstatus & VS_CRASHED)) return NULL;
 261
 262         Train *t = Train::From(v);
 263         if (t->track == TRACK_BIT_WORMHOLE || HasBit((TrackBits)t->track, TrackdirToTrack(info->res.trackdir))) {
 264                 t = t->First();
 265
 266                 /* ALWAYS return the lowest ID (anti-desync!) */
 267                 if (info->best == NULL || t->index < info->best->index) info->best = t;
 268                 return t;
 269         }
 270
 271         return NULL;
 272 }
 273
 274 /**
 275  * Follow a train reservation to the last tile.
 276  *
 277  * @param v the vehicle
 278  * @param train_on_res Is set to a train we might encounter
 279  * @returns The last tile of the reservation or the current train tile if no reservation present.
 280  */
 281 PBSTileInfo FollowTrainReservation(const Train *v, Vehicle **train_on_res)
 282 {
 283         assert(v->type == VEH_TRAIN);
 284
 285         TileIndex tile = v->tile;
 286         Trackdir  trackdir = v->GetVehicleTrackdir();
 287
 288         if (IsRailDepotTile(tile) && !GetDepotReservationTrackBits(tile)) return PBSTileInfo(tile, trackdir, false);
 289
 290         FindTrainOnTrackInfo ftoti;
 291         ftoti.res = FollowReservation(v->owner, GetRailTypeInfo(v->railtype)->compatible_railtypes, tile, trackdir);
 292         ftoti.res.okay = IsSafeWaitingPosition(v, ftoti.res.tile, ftoti.res.trackdir, true, _settings_game.pf.forbid_90_deg);
 293         if (train_on_res != NULL) {
 294                 FindVehicleOnPos(ftoti.res.tile, &ftoti, FindTrainOnTrackEnum);
 295                 if (ftoti.best != NULL) *train_on_res = ftoti.best->First();
 296                 if (*train_on_res == NULL && IsRailStationTile(ftoti.res.tile)) {
 297                         /* The target tile is a rail station. The track follower
 298                          * has stopped on the last platform tile where we haven't
 299                          * found a train. Also check all previous platform tiles
 300                          * for a possible train. */
 301                         TileIndexDiff diff = TileOffsByDiagDir(TrackdirToExitdir(ReverseTrackdir(ftoti.res.trackdir)));
 302                         for (TileIndex st_tile = ftoti.res.tile + diff; *train_on_res == NULL && IsCompatibleTrainStationTile(st_tile, ftoti.res.tile); st_tile += diff) {
 303                                 FindVehicleOnPos(st_tile, &ftoti, FindTrainOnTrackEnum);
 304                                 if (ftoti.best != NULL) *train_on_res = ftoti.best->First();
 305                         }
 306                 }
 307                 if (*train_on_res == NULL && IsTileType(ftoti.res.tile, MP_TUNNELBRIDGE)) {
 308                         /* The target tile is a bridge/tunnel, also check the other end tile. */
 309                         FindVehicleOnPos(GetOtherTunnelBridgeEnd(ftoti.res.tile), &ftoti, FindTrainOnTrackEnum);
 310                         if (ftoti.best != NULL) *train_on_res = ftoti.best->First();
 311                 }
 312         }
 313         return ftoti.res;
 314 }
 315
 316 /**
 317  * Find the train which has reserved a specific path.
 318  *
 319  * @param tile A tile on the path.
 320  * @param track A reserved track on the tile.
 321  * @return The vehicle holding the reservation or NULL if the path is stray.
 322  */
 323 Train *GetTrainForReservation(TileIndex tile, Track track)
 324 {
 325         assert(HasReservedTracks(tile, TrackToTrackBits(track)));
 326         Trackdir  trackdir = TrackToTrackdir(track);
 327
 328         RailTypes rts = GetRailTypeInfo(GetTileRailType(tile))->compatible_railtypes;
 329
 330         /* Follow the path from tile to both ends, one of the end tiles should
 331          * have a train on it. We need FollowReservation to ignore one-way signals
 332          * here, as one of the two search directions will be the "wrong" way. */
 333         for (int i = 0; i < 2; ++i, trackdir = ReverseTrackdir(trackdir)) {
 334                 /* If the tile has a one-way block signal in the current trackdir, skip the
 335                  * search in this direction as the reservation can't come from this side.*/
 336                 if (HasOnewaySignalBlockingTrackdir(tile, ReverseTrackdir(trackdir)) && !HasPbsSignalOnTrackdir(tile, trackdir)) continue;
 337
 338                 FindTrainOnTrackInfo ftoti;
 339                 ftoti.res = FollowReservation(GetTileOwner(tile), rts, tile, trackdir, true);
 340
 341                 FindVehicleOnPos(ftoti.res.tile, &ftoti, FindTrainOnTrackEnum);
 342                 if (ftoti.best != NULL) return ftoti.best;
 343
 344                 /* Special case for stations: check the whole platform for a vehicle. */
 345                 if (IsRailStationTile(ftoti.res.tile)) {
 346                         TileIndexDiff diff = TileOffsByDiagDir(TrackdirToExitdir(ReverseTrackdir(ftoti.res.trackdir)));
 347                         for (TileIndex st_tile = ftoti.res.tile + diff; IsCompatibleTrainStationTile(st_tile, ftoti.res.tile); st_tile += diff) {
 348                                 FindVehicleOnPos(st_tile, &ftoti, FindTrainOnTrackEnum);
 349                                 if (ftoti.best != NULL) return ftoti.best;
 350                         }
 351                 }
 352
 353                 /* Special case for bridges/tunnels: check the other end as well. */
 354                 if (IsTileType(ftoti.res.tile, MP_TUNNELBRIDGE)) {
 355                         FindVehicleOnPos(GetOtherTunnelBridgeEnd(ftoti.res.tile), &ftoti, FindTrainOnTrackEnum);
 356                         if (ftoti.best != NULL) return ftoti.best;
 357                 }
 358         }
 359
 360         return NULL;
 361 }
 362
 363 /**
 364  * Determine whether a certain track on a tile is a safe position to end a path.
 365  *
 366  * @param v the vehicle to test for
 367  * @param tile The tile
 368  * @param trackdir The trackdir to test
 369  * @param include_line_end Should end-of-line tiles be considered safe?
 370  * @param forbid_90deg Don't allow trains to make 90 degree turns
 371  * @return True if it is a safe position
 372  */
 373 bool IsSafeWaitingPosition(const Train *v, TileIndex tile, Trackdir trackdir, bool include_line_end, bool forbid_90deg)
 374 {
 375         if (IsRailDepotTile(tile)) return true;
 376
 377         if (IsTileType(tile, MP_RAILWAY)) {
 378                 /* For non-pbs signals, stop on the signal tile. */
 379                 if (HasSignalOnTrackdir(tile, trackdir) && !IsPbsSignal(GetSignalType(tile, TrackdirToTrack(trackdir)))) return true;
 380         }
 381
 382         /* Check next tile. For performance reasons, we check for 90 degree turns ourself. */
 383         CFollowTrackRail ft(v, GetRailTypeInfo(v->railtype)->compatible_railtypes);
 384
 385         /* End of track? */
 386         if (!ft.Follow(tile, trackdir)) {
 387                 /* Last tile of a terminus station is a safe position. */
 388                 if (include_line_end) return true;
 389         }
 390
 391         /* Check for reachable tracks. */
 392         ft.m_new_td_bits &= DiagdirReachesTrackdirs(ft.m_exitdir);
 393         if (forbid_90deg) ft.m_new_td_bits &= ~TrackdirCrossesTrackdirs(trackdir);
 394         if (ft.m_new_td_bits == TRACKDIR_BIT_NONE) return include_line_end;
 395
 396         if (ft.m_new_td_bits != TRACKDIR_BIT_NONE && KillFirstBit(ft.m_new_td_bits) == TRACKDIR_BIT_NONE) {
 397                 Trackdir td = FindFirstTrackdir(ft.m_new_td_bits);
 398                 /* PBS signal on next trackdir? Safe position. */
 399                 if (HasPbsSignalOnTrackdir(ft.m_new_tile, td)) return true;
 400                 /* One-way PBS signal against us? Safe if end-of-line is allowed. */
 401                 if (IsTileType(ft.m_new_tile, MP_RAILWAY) && HasSignalOnTrackdir(ft.m_new_tile, ReverseTrackdir(td)) &&
 402                                 GetSignalType(ft.m_new_tile, TrackdirToTrack(td)) == SIGTYPE_PBS_ONEWAY) {
 403                         return include_line_end;
 404                 }
 405         }
 406
 407         return false;
 408 }
 409
 410 /**
 411  * Check if a safe position is free.
 412  *
 413  * @param v the vehicle to test for
 414  * @param tile The tile
 415  * @param trackdir The trackdir to test
 416  * @param forbid_90deg Don't allow trains to make 90 degree turns
 417  * @return True if the position is free
 418  */
 419 bool IsWaitingPositionFree(const Train *v, TileIndex tile, Trackdir trackdir, bool forbid_90deg)
 420 {
 421         Track     track = TrackdirToTrack(trackdir);
 422         TrackBits reserved = GetReservedTrackbits(tile);
 423
 424         /* Tile reserved? Can never be a free waiting position. */
 425         if (TrackOverlapsTracks(reserved, track)) return false;
 426
 427         /* Not reserved and depot or not a pbs signal -> free. */
 428         if (IsRailDepotTile(tile)) return true;
 429         if (IsTileType(tile, MP_RAILWAY) && HasSignalOnTrackdir(tile, trackdir) && !IsPbsSignal(GetSignalType(tile, track))) return true;
 430
 431         /* Check the next tile, if it's a PBS signal, it has to be free as well. */
 432         CFollowTrackRail ft(v, GetRailTypeInfo(v->railtype)->compatible_railtypes);
 433
 434         if (!ft.Follow(tile, trackdir)) return true;
 435
 436         /* Check for reachable tracks. */
 437         ft.m_new_td_bits &= DiagdirReachesTrackdirs(ft.m_exitdir);
 438         if (forbid_90deg) ft.m_new_td_bits &= ~TrackdirCrossesTrackdirs(trackdir);
 439
 440         return !HasReservedTracks(ft.m_new_tile, TrackdirBitsToTrackBits(ft.m_new_td_bits));
 441 }