src/pathfinder/follow_track.hpp

   1 /*
   2  * This file is part of OpenTTD.
   3  * 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.
   4  * 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.
   5  * 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/>.
   6  */
   7
   8 /** @file follow_track.hpp Template function for track followers */
   9
  10 #ifndef  FOLLOW_TRACK_HPP
  11 #define  FOLLOW_TRACK_HPP
  12
  13 #include "../pbs.h"
  14 #include "../roadveh.h"
  15 #include "../station_base.h"
  16 #include "../train.h"
  17 #include "../tunnelbridge.h"
  18 #include "../tunnelbridge_map.h"
  19 #include "../depot_map.h"
  20 #include "pathfinder_func.h"
  21
  22 /**
  23  * Track follower helper template class (can serve pathfinders and vehicle
  24  *  controllers). See 6 different typedefs below for 3 different transport
  25  *  types w/ or w/o 90-deg turns allowed
  26  */
  27 template <TransportType Ttr_type_, typename VehicleType, bool T90deg_turns_allowed_ = true, bool Tmask_reserved_tracks = false>
  28 struct CFollowTrackT
  29 {
  30         enum ErrorCode {
  31                 EC_NONE,
  32                 EC_OWNER,
  33                 EC_RAIL_ROAD_TYPE,
  34                 EC_90DEG,
  35                 EC_NO_WAY,
  36                 EC_RESERVED,
  37         };
  38
  39         const VehicleType  *m_veh;           ///< moving vehicle
  40         Owner               m_veh_owner;     ///< owner of the vehicle
  41         TileIndex           m_old_tile;      ///< the origin (vehicle moved from) before move
  42         Trackdir            m_old_td;        ///< the trackdir (the vehicle was on) before move
  43         TileIndex           m_new_tile;      ///< the new tile (the vehicle has entered)
  44         TrackdirBits        m_new_td_bits;   ///< the new set of available trackdirs
  45         DiagDirection       m_exitdir;       ///< exit direction (leaving the old tile)
  46         bool                m_is_tunnel;     ///< last turn passed tunnel
  47         bool                m_is_bridge;     ///< last turn passed bridge ramp
  48         bool                m_is_station;    ///< last turn passed station
  49         int                 m_tiles_skipped; ///< number of skipped tunnel or station tiles
  50         ErrorCode           m_err;
  51         RailTypes           m_railtypes;
  52
  53         inline CFollowTrackT(const VehicleType *v = nullptr, RailTypes railtype_override = INVALID_RAILTYPES)
  54         {
  55                 Init(v, railtype_override);
  56         }
  57
  58         inline CFollowTrackT(Owner o, RailTypes railtype_override = INVALID_RAILTYPES)
  59         {
  60                 assert(IsRailTT());
  61                 m_veh = nullptr;
  62                 Init(o, railtype_override);
  63         }
  64
  65         inline void Init(const VehicleType *v, RailTypes railtype_override)
  66         {
  67                 assert(!IsRailTT() || (v != nullptr && v->type == VEH_TRAIN));
  68                 m_veh = v;
  69                 Init(v != nullptr ? v->owner : INVALID_OWNER, IsRailTT() && railtype_override == INVALID_RAILTYPES ? Train::From(v)->compatible_railtypes : railtype_override);
  70         }
  71
  72         inline void Init(Owner o, RailTypes railtype_override)
  73         {
  74                 assert(!IsRoadTT() || m_veh != nullptr);
  75                 assert(!IsRailTT() || railtype_override != INVALID_RAILTYPES);
  76                 m_veh_owner = o;
  77                 /* don't worry, all is inlined so compiler should remove unnecessary initializations */
  78                 m_old_tile = INVALID_TILE;
  79                 m_old_td = INVALID_TRACKDIR;
  80                 m_new_tile = INVALID_TILE;
  81                 m_new_td_bits = TRACKDIR_BIT_NONE;
  82                 m_exitdir = INVALID_DIAGDIR;
  83                 m_is_station = m_is_bridge = m_is_tunnel = false;
  84                 m_tiles_skipped = 0;
  85                 m_err = EC_NONE;
  86                 m_railtypes = railtype_override;
  87         }
  88
  89         debug_inline static TransportType TT() { return Ttr_type_; }
  90         debug_inline static bool IsWaterTT() { return TT() == TRANSPORT_WATER; }
  91         debug_inline static bool IsRailTT() { return TT() == TRANSPORT_RAIL; }
  92         inline bool IsTram() { return IsRoadTT() && RoadTypeIsTram(RoadVehicle::From(m_veh)->roadtype); }
  93         debug_inline static bool IsRoadTT() { return TT() == TRANSPORT_ROAD; }
  94         inline static bool Allow90degTurns() { return T90deg_turns_allowed_; }
  95         inline static bool DoTrackMasking() { return Tmask_reserved_tracks; }
  96
  97         /** Tests if a tile is a road tile with a single tramtrack (tram can reverse) */
  98         inline DiagDirection GetSingleTramBit(TileIndex tile)
  99         {
 100                 assert(IsTram()); // this function shouldn't be called in other cases
 101
 102                 if (IsNormalRoadTile(tile)) {
 103                         RoadBits rb = GetRoadBits(tile, RTT_TRAM);
 104                         switch (rb) {
 105                                 case ROAD_NW: return DIAGDIR_NW;
 106                                 case ROAD_SW: return DIAGDIR_SW;
 107                                 case ROAD_SE: return DIAGDIR_SE;
 108                                 case ROAD_NE: return DIAGDIR_NE;
 109                                 default: break;
 110                         }
 111                 }
 112                 return INVALID_DIAGDIR;
 113         }
 114
 115         /**
 116          * main follower routine. Fills all members and return true on success.
 117          *  Otherwise returns false if track can't be followed.
 118          */
 119         inline bool Follow(TileIndex old_tile, Trackdir old_td)
 120         {
 121                 m_old_tile = old_tile;
 122                 m_old_td = old_td;
 123                 m_err = EC_NONE;
 124
 125                 assert([&]() {
 126                         if (IsTram() && GetSingleTramBit(m_old_tile) != INVALID_DIAGDIR) return true; // Skip the check for single tram bits
 127                         const uint sub_mode = (IsRoadTT() && m_veh != nullptr) ? (this->IsTram() ? RTT_TRAM : RTT_ROAD) : 0;
 128                         const TrackdirBits old_tile_valid_dirs = TrackStatusToTrackdirBits(GetTileTrackStatus(m_old_tile, TT(), sub_mode));
 129                         return (old_tile_valid_dirs & TrackdirToTrackdirBits(m_old_td)) != TRACKDIR_BIT_NONE;
 130                 }());
 131
 132                 m_exitdir = TrackdirToExitdir(m_old_td);
 133                 if (ForcedReverse()) return true;
 134                 if (!CanExitOldTile()) return false;
 135                 FollowTileExit();
 136                 if (!QueryNewTileTrackStatus()) return TryReverse();
 137                 m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
 138                 if (m_new_td_bits == TRACKDIR_BIT_NONE || !CanEnterNewTile()) {
 139                         /* In case we can't enter the next tile, but are
 140                          * a normal road vehicle, then we can actually
 141                          * try to reverse as this is the end of the road.
 142                          * Trams can only turn on the appropriate bits in
 143                          * which case reaching this would mean a dead end
 144                          * near a building and in that case there would
 145                          * a "false" QueryNewTileTrackStatus result and
 146                          * as such reversing is already tried. The fact
 147                          * that function failed can have to do with a
 148                          * missing road bit, or inability to connect the
 149                          * different bits due to slopes. */
 150                         if (IsRoadTT() && !IsTram() && TryReverse()) return true;
 151
 152                         /* CanEnterNewTile already set a reason.
 153                          * Do NOT overwrite it (important for example for EC_RAIL_ROAD_TYPE).
 154                          * Only set a reason if CanEnterNewTile was not called */
 155                         if (m_new_td_bits == TRACKDIR_BIT_NONE) m_err = EC_NO_WAY;
 156
 157                         return false;
 158                 }
 159                 if ((!IsRailTT() && !Allow90degTurns()) || (IsRailTT() && Rail90DegTurnDisallowed(GetTileRailType(m_old_tile), GetTileRailType(m_new_tile), !Allow90degTurns()))) {
 160                         m_new_td_bits &= (TrackdirBits)~(int)TrackdirCrossesTrackdirs(m_old_td);
 161                         if (m_new_td_bits == TRACKDIR_BIT_NONE) {
 162                                 m_err = EC_90DEG;
 163                                 return false;
 164                         }
 165                 }
 166                 return true;
 167         }
 168
 169         inline bool MaskReservedTracks()
 170         {
 171                 if (!DoTrackMasking()) return true;
 172
 173                 if (m_is_station) {
 174                         /* Check skipped station tiles as well. */
 175                         TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
 176                         for (TileIndex tile = m_new_tile - diff * m_tiles_skipped; tile != m_new_tile; tile += diff) {
 177                                 if (HasStationReservation(tile)) {
 178                                         m_new_td_bits = TRACKDIR_BIT_NONE;
 179                                         m_err = EC_RESERVED;
 180                                         return false;
 181                                 }
 182                         }
 183                 }
 184
 185                 TrackBits reserved = GetReservedTrackbits(m_new_tile);
 186                 /* Mask already reserved trackdirs. */
 187                 m_new_td_bits &= ~TrackBitsToTrackdirBits(reserved);
 188                 /* Mask out all trackdirs that conflict with the reservation. */
 189                 for (Track t : SetTrackBitIterator(TrackdirBitsToTrackBits(m_new_td_bits))) {
 190                         if (TracksOverlap(reserved | TrackToTrackBits(t))) m_new_td_bits &= ~TrackToTrackdirBits(t);
 191                 }
 192                 if (m_new_td_bits == TRACKDIR_BIT_NONE) {
 193                         m_err = EC_RESERVED;
 194                         return false;
 195                 }
 196                 return true;
 197         }
 198
 199 protected:
 200         /** Follow the m_exitdir from m_old_tile and fill m_new_tile and m_tiles_skipped */
 201         inline void FollowTileExit()
 202         {
 203                 m_is_station = m_is_bridge = m_is_tunnel = false;
 204                 m_tiles_skipped = 0;
 205
 206                 /* extra handling for tunnels and bridges in our direction */
 207                 if (IsTileType(m_old_tile, MP_TUNNELBRIDGE)) {
 208                         DiagDirection enterdir = GetTunnelBridgeDirection(m_old_tile);
 209                         if (enterdir == m_exitdir) {
 210                                 /* we are entering the tunnel / bridge */
 211                                 if (IsTunnel(m_old_tile)) {
 212                                         m_is_tunnel = true;
 213                                         m_new_tile = GetOtherTunnelEnd(m_old_tile);
 214                                 } else { // IsBridge(m_old_tile)
 215                                         m_is_bridge = true;
 216                                         m_new_tile = GetOtherBridgeEnd(m_old_tile);
 217                                 }
 218                                 m_tiles_skipped = GetTunnelBridgeLength(m_new_tile, m_old_tile);
 219                                 return;
 220                         }
 221                         assert(ReverseDiagDir(enterdir) == m_exitdir);
 222                 }
 223
 224                 /* normal or station tile, do one step */
 225                 m_new_tile = TileAddByDiagDir(m_old_tile, m_exitdir);
 226
 227                 /* special handling for stations */
 228                 if (IsRailTT() && HasStationTileRail(m_new_tile)) {
 229                         m_is_station = true;
 230                 } else if (IsRoadTT() && IsStationRoadStopTile(m_new_tile)) {
 231                         m_is_station = true;
 232                 }
 233         }
 234
 235         /** stores track status (available trackdirs) for the new tile into m_new_td_bits */
 236         inline bool QueryNewTileTrackStatus()
 237         {
 238                 if (IsRailTT() && IsPlainRailTile(m_new_tile)) {
 239                         m_new_td_bits = (TrackdirBits)(GetTrackBits(m_new_tile) * 0x101);
 240                 } else if (IsRoadTT()) {
 241                         m_new_td_bits = GetTrackdirBitsForRoad(m_new_tile, this->IsTram() ? RTT_TRAM : RTT_ROAD);
 242                 } else {
 243                         m_new_td_bits = TrackStatusToTrackdirBits(GetTileTrackStatus(m_new_tile, TT(), 0));
 244                 }
 245                 return (m_new_td_bits != TRACKDIR_BIT_NONE);
 246         }
 247
 248         /** return true if we can leave m_old_tile in m_exitdir */
 249         inline bool CanExitOldTile()
 250         {
 251                 /* road stop can be left at one direction only unless it's a drive-through stop */
 252                 if (IsRoadTT() && IsBayRoadStopTile(m_old_tile)) {
 253                         DiagDirection exitdir = GetRoadStopDir(m_old_tile);
 254                         if (exitdir != m_exitdir) {
 255                                 m_err = EC_NO_WAY;
 256                                 return false;
 257                         }
 258                 }
 259
 260                 /* single tram bits can only be left in one direction */
 261                 if (IsTram()) {
 262                         DiagDirection single_tram = GetSingleTramBit(m_old_tile);
 263                         if (single_tram != INVALID_DIAGDIR && single_tram != m_exitdir) {
 264                                 m_err = EC_NO_WAY;
 265                                 return false;
 266                         }
 267                 }
 268
 269                 /* road depots can be also left in one direction only */
 270                 if (IsRoadTT() && IsDepotTypeTile(m_old_tile, TT())) {
 271                         DiagDirection exitdir = GetRoadDepotDirection(m_old_tile);
 272                         if (exitdir != m_exitdir) {
 273                                 m_err = EC_NO_WAY;
 274                                 return false;
 275                         }
 276                 }
 277                 return true;
 278         }
 279
 280         /** return true if we can enter m_new_tile from m_exitdir */
 281         inline bool CanEnterNewTile()
 282         {
 283                 if (IsRoadTT() && IsBayRoadStopTile(m_new_tile)) {
 284                         /* road stop can be entered from one direction only unless it's a drive-through stop */
 285                         DiagDirection exitdir = GetRoadStopDir(m_new_tile);
 286                         if (ReverseDiagDir(exitdir) != m_exitdir) {
 287                                 m_err = EC_NO_WAY;
 288                                 return false;
 289                         }
 290                 }
 291
 292                 /* single tram bits can only be entered from one direction */
 293                 if (IsTram()) {
 294                         DiagDirection single_tram = GetSingleTramBit(m_new_tile);
 295                         if (single_tram != INVALID_DIAGDIR && single_tram != ReverseDiagDir(m_exitdir)) {
 296                                 m_err = EC_NO_WAY;
 297                                 return false;
 298                         }
 299                 }
 300
 301                 /* road and rail depots can also be entered from one direction only */
 302                 if (IsRoadTT() && IsDepotTypeTile(m_new_tile, TT())) {
 303                         DiagDirection exitdir = GetRoadDepotDirection(m_new_tile);
 304                         if (ReverseDiagDir(exitdir) != m_exitdir) {
 305                                 m_err = EC_NO_WAY;
 306                                 return false;
 307                         }
 308                         /* don't try to enter other company's depots */
 309                         if (GetTileOwner(m_new_tile) != m_veh_owner) {
 310                                 m_err = EC_OWNER;
 311                                 return false;
 312                         }
 313                 }
 314                 if (IsRailTT() && IsDepotTypeTile(m_new_tile, TT())) {
 315                         DiagDirection exitdir = GetRailDepotDirection(m_new_tile);
 316                         if (ReverseDiagDir(exitdir) != m_exitdir) {
 317                                 m_err = EC_NO_WAY;
 318                                 return false;
 319                         }
 320                 }
 321
 322                 /* rail transport is possible only on tiles with the same owner as vehicle */
 323                 if (IsRailTT() && GetTileOwner(m_new_tile) != m_veh_owner) {
 324                         /* different owner */
 325                         m_err = EC_NO_WAY;
 326                         return false;
 327                 }
 328
 329                 /* rail transport is possible only on compatible rail types */
 330                 if (IsRailTT()) {
 331                         RailType rail_type = GetTileRailType(m_new_tile);
 332                         if (!HasBit(m_railtypes, rail_type)) {
 333                                 /* incompatible rail type */
 334                                 m_err = EC_RAIL_ROAD_TYPE;
 335                                 return false;
 336                         }
 337                 }
 338
 339                 /* road transport is possible only on compatible road types */
 340                 if (IsRoadTT()) {
 341                         const RoadVehicle *v = RoadVehicle::From(m_veh);
 342                         RoadType roadtype = GetRoadType(m_new_tile, GetRoadTramType(v->roadtype));
 343                         if (!HasBit(v->compatible_roadtypes, roadtype)) {
 344                                 /* incompatible road type */
 345                                 m_err = EC_RAIL_ROAD_TYPE;
 346                                 return false;
 347                         }
 348                 }
 349
 350                 /* tunnel holes and bridge ramps can be entered only from proper direction */
 351                 if (IsTileType(m_new_tile, MP_TUNNELBRIDGE)) {
 352                         if (IsTunnel(m_new_tile)) {
 353                                 if (!m_is_tunnel) {
 354                                         DiagDirection tunnel_enterdir = GetTunnelBridgeDirection(m_new_tile);
 355                                         if (tunnel_enterdir != m_exitdir) {
 356                                                 m_err = EC_NO_WAY;
 357                                                 return false;
 358                                         }
 359                                 }
 360                         } else { // IsBridge(m_new_tile)
 361                                 if (!m_is_bridge) {
 362                                         DiagDirection ramp_enderdir = GetTunnelBridgeDirection(m_new_tile);
 363                                         if (ramp_enderdir != m_exitdir) {
 364                                                 m_err = EC_NO_WAY;
 365                                                 return false;
 366                                         }
 367                                 }
 368                         }
 369                 }
 370
 371                 /* special handling for rail stations - get to the end of platform */
 372                 if (IsRailTT() && m_is_station) {
 373                         /* entered railway station
 374                          * get platform length */
 375                         uint length = BaseStation::GetByTile(m_new_tile)->GetPlatformLength(m_new_tile, TrackdirToExitdir(m_old_td));
 376                         /* how big step we must do to get to the last platform tile? */
 377                         m_tiles_skipped = length - 1;
 378                         /* move to the platform end */
 379                         TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
 380                         diff *= m_tiles_skipped;
 381                         m_new_tile = TileAdd(m_new_tile, diff);
 382                         return true;
 383                 }
 384
 385                 return true;
 386         }
 387
 388         /** return true if we must reverse (in depots and single tram bits) */
 389         inline bool ForcedReverse()
 390         {
 391                 /* rail and road depots cause reversing */
 392                 if (!IsWaterTT() && IsDepotTypeTile(m_old_tile, TT())) {
 393                         DiagDirection exitdir = IsRailTT() ? GetRailDepotDirection(m_old_tile) : GetRoadDepotDirection(m_old_tile);
 394                         if (exitdir != m_exitdir) {
 395                                 /* reverse */
 396                                 m_new_tile = m_old_tile;
 397                                 m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
 398                                 m_exitdir = exitdir;
 399                                 m_tiles_skipped = 0;
 400                                 m_is_tunnel = m_is_bridge = m_is_station = false;
 401                                 return true;
 402                         }
 403                 }
 404
 405                 /* Single tram bits and standard road stops cause reversing. */
 406                 if (IsRoadTT() && ((IsTram() && GetSingleTramBit(m_old_tile) == ReverseDiagDir(m_exitdir)) ||
 407                                 (IsBayRoadStopTile(m_old_tile) && GetRoadStopDir(m_old_tile) == ReverseDiagDir(m_exitdir)))) {
 408                         /* reverse */
 409                         m_new_tile = m_old_tile;
 410                         m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
 411                         m_exitdir = ReverseDiagDir(m_exitdir);
 412                         m_tiles_skipped = 0;
 413                         m_is_tunnel = m_is_bridge = m_is_station = false;
 414                         return true;
 415                 }
 416
 417                 return false;
 418         }
 419
 420         /** return true if we successfully reversed at end of road/track */
 421         inline bool TryReverse()
 422         {
 423                 if (IsRoadTT() && !IsTram()) {
 424                         /* if we reached the end of road, we can reverse the RV and continue moving */
 425                         m_exitdir = ReverseDiagDir(m_exitdir);
 426                         /* new tile will be the same as old one */
 427                         m_new_tile = m_old_tile;
 428                         /* set new trackdir bits to all reachable trackdirs */
 429                         QueryNewTileTrackStatus();
 430                         m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
 431                         if (m_new_td_bits != TRACKDIR_BIT_NONE) {
 432                                 /* we have some trackdirs reachable after reversal */
 433                                 return true;
 434                         }
 435                 }
 436                 m_err = EC_NO_WAY;
 437                 return false;
 438         }
 439
 440 public:
 441         /** Helper for pathfinders - get min/max speed on the m_old_tile/m_old_td */
 442         int GetSpeedLimit(int *pmin_speed = nullptr) const
 443         {
 444                 int min_speed = 0;
 445                 int max_speed = INT_MAX; // no limit
 446
 447                 /* Check for on-bridge speed limit */
 448                 if (!IsWaterTT() && IsBridgeTile(m_old_tile)) {
 449                         int spd = GetBridgeSpec(GetBridgeType(m_old_tile))->speed;
 450                         if (IsRoadTT()) spd *= 2;
 451                         max_speed = std::min(max_speed, spd);
 452                 }
 453                 /* Check for speed limit imposed by railtype */
 454                 if (IsRailTT()) {
 455                         uint16_t rail_speed = GetRailTypeInfo(GetRailType(m_old_tile))->max_speed;
 456                         if (rail_speed > 0) max_speed = std::min<int>(max_speed, rail_speed);
 457                 }
 458                 if (IsRoadTT()) {
 459                         /* max_speed is already in roadvehicle units, no need to further modify (divide by 2) */
 460                         uint16_t road_speed = GetRoadTypeInfo(GetRoadType(m_old_tile, GetRoadTramType(RoadVehicle::From(m_veh)->roadtype)))->max_speed;
 461                         if (road_speed > 0) max_speed = std::min<int>(max_speed, road_speed);
 462                 }
 463
 464                 /* if min speed was requested, return it */
 465                 if (pmin_speed != nullptr) *pmin_speed = min_speed;
 466                 return max_speed;
 467         }
 468 };
 469
 470 typedef CFollowTrackT<TRANSPORT_WATER, Ship,        true > CFollowTrackWater;
 471 typedef CFollowTrackT<TRANSPORT_ROAD,  RoadVehicle, true > CFollowTrackRoad;
 472 typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       true > CFollowTrackRail;
 473
 474 typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       false> CFollowTrackRailNo90;
 475
 476 typedef CFollowTrackT<TRANSPORT_RAIL, Train, true,  true > CFollowTrackFreeRail;
 477 typedef CFollowTrackT<TRANSPORT_RAIL, Train, false, true > CFollowTrackFreeRailNo90;
 478
 479 #endif /* FOLLOW_TRACK_HPP */