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 "pf_performance_timer.hpp"
  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         CPerformanceTimer  *m_pPerf;
  52         RailTypes           m_railtypes;
  53
  54         inline CFollowTrackT(const VehicleType *v = nullptr, RailTypes railtype_override = INVALID_RAILTYPES, CPerformanceTimer *pPerf = nullptr)
  55         {
  56                 Init(v, railtype_override, pPerf);
  57         }
  58
  59         inline CFollowTrackT(Owner o, RailTypes railtype_override = INVALID_RAILTYPES, CPerformanceTimer *pPerf = nullptr)
  60         {
  61                 assert(IsRailTT());
  62                 m_veh = nullptr;
  63                 Init(o, railtype_override, pPerf);
  64         }
  65
  66         inline void Init(const VehicleType *v, RailTypes railtype_override, CPerformanceTimer *pPerf)
  67         {
  68                 assert(!IsRailTT() || (v != nullptr && v->type == VEH_TRAIN));
  69                 m_veh = v;
  70                 Init(v != nullptr ? v->owner : INVALID_OWNER, IsRailTT() && railtype_override == INVALID_RAILTYPES ? Train::From(v)->compatible_railtypes : railtype_override, pPerf);
  71         }
  72
  73         inline void Init(Owner o, RailTypes railtype_override, CPerformanceTimer *pPerf)
  74         {
  75                 assert(!IsRoadTT() || m_veh != nullptr);
  76                 assert(!IsRailTT() || railtype_override != INVALID_RAILTYPES);
  77                 m_veh_owner = o;
  78                 m_pPerf = pPerf;
  79                 /* don't worry, all is inlined so compiler should remove unnecessary initializations */
  80                 m_old_tile = INVALID_TILE;
  81                 m_old_td = INVALID_TRACKDIR;
  82                 m_new_tile = INVALID_TILE;
  83                 m_new_td_bits = TRACKDIR_BIT_NONE;
  84                 m_exitdir = INVALID_DIAGDIR;
  85                 m_is_station = m_is_bridge = m_is_tunnel = false;
  86                 m_tiles_skipped = 0;
  87                 m_err = EC_NONE;
  88                 m_railtypes = railtype_override;
  89         }
  90
  91         inline static TransportType TT() { return Ttr_type_; }
  92         inline static bool IsWaterTT() { return TT() == TRANSPORT_WATER; }
  93         inline static bool IsRailTT() { return TT() == TRANSPORT_RAIL; }
  94         inline bool IsTram() { return IsRoadTT() && RoadTypeIsTram(RoadVehicle::From(m_veh)->roadtype); }
  95         inline static bool IsRoadTT() { return TT() == TRANSPORT_ROAD; }
  96         inline static bool Allow90degTurns() { return T90deg_turns_allowed_; }
  97         inline static bool DoTrackMasking() { return Tmask_reserved_tracks; }
  98
  99         /** Tests if a tile is a road tile with a single tramtrack (tram can reverse) */
 100         inline DiagDirection GetSingleTramBit(TileIndex tile)
 101         {
 102                 assert(IsTram()); // this function shouldn't be called in other cases
 103
 104                 if (IsNormalRoadTile(tile)) {
 105                         RoadBits rb = GetRoadBits(tile, RTT_TRAM);
 106                         switch (rb) {
 107                                 case ROAD_NW: return DIAGDIR_NW;
 108                                 case ROAD_SW: return DIAGDIR_SW;
 109                                 case ROAD_SE: return DIAGDIR_SE;
 110                                 case ROAD_NE: return DIAGDIR_NE;
 111                                 default: break;
 112                         }
 113                 }
 114                 return INVALID_DIAGDIR;
 115         }
 116
 117         /**
 118          * main follower routine. Fills all members and return true on success.
 119          *  Otherwise returns false if track can't be followed.
 120          */
 121         inline bool Follow(TileIndex old_tile, Trackdir old_td)
 122         {
 123                 m_old_tile = old_tile;
 124                 m_old_td = old_td;
 125                 m_err = EC_NONE;
 126                 assert(
 127                         ((TrackStatusToTrackdirBits(
 128                                 GetTileTrackStatus(m_old_tile, TT(), (IsRoadTT() && m_veh != nullptr) ? (this->IsTram() ? RTT_TRAM : RTT_ROAD) : 0)
 129                         ) & TrackdirToTrackdirBits(m_old_td)) != 0) ||
 130                         (IsTram() && GetSingleTramBit(m_old_tile) != INVALID_DIAGDIR) // Disable the assertion for single tram bits
 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                 Track t;
 190                 FOR_EACH_SET_TRACK(t, TrackdirBitsToTrackBits(m_new_td_bits)) {
 191                         if (TracksOverlap(reserved | TrackToTrackBits(t))) m_new_td_bits &= ~TrackToTrackdirBits(t);
 192                 }
 193                 if (m_new_td_bits == TRACKDIR_BIT_NONE) {
 194                         m_err = EC_RESERVED;
 195                         return false;
 196                 }
 197                 return true;
 198         }
 199
 200 protected:
 201         /** Follow the m_exitdir from m_old_tile and fill m_new_tile and m_tiles_skipped */
 202         inline void FollowTileExit()
 203         {
 204                 m_is_station = m_is_bridge = m_is_tunnel = false;
 205                 m_tiles_skipped = 0;
 206
 207                 /* extra handling for tunnels and bridges in our direction */
 208                 if (IsTileType(m_old_tile, MP_TUNNELBRIDGE)) {
 209                         DiagDirection enterdir = GetTunnelBridgeDirection(m_old_tile);
 210                         if (enterdir == m_exitdir) {
 211                                 /* we are entering the tunnel / bridge */
 212                                 if (IsTunnel(m_old_tile)) {
 213                                         m_is_tunnel = true;
 214                                         m_new_tile = GetOtherTunnelEnd(m_old_tile);
 215                                 } else { // IsBridge(m_old_tile)
 216                                         m_is_bridge = true;
 217                                         m_new_tile = GetOtherBridgeEnd(m_old_tile);
 218                                 }
 219                                 m_tiles_skipped = GetTunnelBridgeLength(m_new_tile, m_old_tile);
 220                                 return;
 221                         }
 222                         assert(ReverseDiagDir(enterdir) == m_exitdir);
 223                 }
 224
 225                 /* normal or station tile, do one step */
 226                 m_new_tile = TileAddByDiagDir(m_old_tile, m_exitdir);
 227
 228                 /* special handling for stations */
 229                 if (IsRailTT() && HasStationTileRail(m_new_tile)) {
 230                         m_is_station = true;
 231                 } else if (IsRoadTT() && IsRoadStopTile(m_new_tile)) {
 232                         m_is_station = true;
 233                 }
 234         }
 235
 236         /** stores track status (available trackdirs) for the new tile into m_new_td_bits */
 237         inline bool QueryNewTileTrackStatus()
 238         {
 239                 CPerfStart perf(*m_pPerf);
 240                 if (IsRailTT() && IsPlainRailTile(m_new_tile)) {
 241                         m_new_td_bits = (TrackdirBits)(GetTrackBits(m_new_tile) * 0x101);
 242                 } else {
 243                         m_new_td_bits = TrackStatusToTrackdirBits(GetTileTrackStatus(m_new_tile, TT(), IsRoadTT() ? (this->IsTram() ? RTT_TRAM : RTT_ROAD) : 0));
 244
 245                         if (IsTram() && m_new_td_bits == TRACKDIR_BIT_NONE) {
 246                                 /* GetTileTrackStatus() returns 0 for single tram bits.
 247                                  * As we cannot change it there (easily) without breaking something, change it here */
 248                                 switch (GetSingleTramBit(m_new_tile)) {
 249                                         case DIAGDIR_NE:
 250                                         case DIAGDIR_SW:
 251                                                 m_new_td_bits = TRACKDIR_BIT_X_NE | TRACKDIR_BIT_X_SW;
 252                                                 break;
 253
 254                                         case DIAGDIR_NW:
 255                                         case DIAGDIR_SE:
 256                                                 m_new_td_bits = TRACKDIR_BIT_Y_NW | TRACKDIR_BIT_Y_SE;
 257                                                 break;
 258
 259                                         default: break;
 260                                 }
 261                         }
 262                 }
 263                 return (m_new_td_bits != TRACKDIR_BIT_NONE);
 264         }
 265
 266         /** return true if we can leave m_old_tile in m_exitdir */
 267         inline bool CanExitOldTile()
 268         {
 269                 /* road stop can be left at one direction only unless it's a drive-through stop */
 270                 if (IsRoadTT() && IsStandardRoadStopTile(m_old_tile)) {
 271                         DiagDirection exitdir = GetRoadStopDir(m_old_tile);
 272                         if (exitdir != m_exitdir) {
 273                                 m_err = EC_NO_WAY;
 274                                 return false;
 275                         }
 276                 }
 277
 278                 /* single tram bits can only be left in one direction */
 279                 if (IsTram()) {
 280                         DiagDirection single_tram = GetSingleTramBit(m_old_tile);
 281                         if (single_tram != INVALID_DIAGDIR && single_tram != m_exitdir) {
 282                                 m_err = EC_NO_WAY;
 283                                 return false;
 284                         }
 285                 }
 286
 287                 /* road depots can be also left in one direction only */
 288                 if (IsRoadTT() && IsDepotTypeTile(m_old_tile, TT())) {
 289                         DiagDirection exitdir = GetRoadDepotDirection(m_old_tile);
 290                         if (exitdir != m_exitdir) {
 291                                 m_err = EC_NO_WAY;
 292                                 return false;
 293                         }
 294                 }
 295                 return true;
 296         }
 297
 298         /** return true if we can enter m_new_tile from m_exitdir */
 299         inline bool CanEnterNewTile()
 300         {
 301                 if (IsRoadTT() && IsStandardRoadStopTile(m_new_tile)) {
 302                         /* road stop can be entered from one direction only unless it's a drive-through stop */
 303                         DiagDirection exitdir = GetRoadStopDir(m_new_tile);
 304                         if (ReverseDiagDir(exitdir) != m_exitdir) {
 305                                 m_err = EC_NO_WAY;
 306                                 return false;
 307                         }
 308                 }
 309
 310                 /* single tram bits can only be entered from one direction */
 311                 if (IsTram()) {
 312                         DiagDirection single_tram = GetSingleTramBit(m_new_tile);
 313                         if (single_tram != INVALID_DIAGDIR && single_tram != ReverseDiagDir(m_exitdir)) {
 314                                 m_err = EC_NO_WAY;
 315                                 return false;
 316                         }
 317                 }
 318
 319                 /* road and rail depots can also be entered from one direction only */
 320                 if (IsRoadTT() && IsDepotTypeTile(m_new_tile, TT())) {
 321                         DiagDirection exitdir = GetRoadDepotDirection(m_new_tile);
 322                         if (ReverseDiagDir(exitdir) != m_exitdir) {
 323                                 m_err = EC_NO_WAY;
 324                                 return false;
 325                         }
 326                         /* don't try to enter other company's depots */
 327                         if (GetTileOwner(m_new_tile) != m_veh_owner) {
 328                                 m_err = EC_OWNER;
 329                                 return false;
 330                         }
 331                 }
 332                 if (IsRailTT() && IsDepotTypeTile(m_new_tile, TT())) {
 333                         DiagDirection exitdir = GetRailDepotDirection(m_new_tile);
 334                         if (ReverseDiagDir(exitdir) != m_exitdir) {
 335                                 m_err = EC_NO_WAY;
 336                                 return false;
 337                         }
 338                 }
 339
 340                 /* rail transport is possible only on tiles with the same owner as vehicle */
 341                 if (IsRailTT() && GetTileOwner(m_new_tile) != m_veh_owner) {
 342                         /* different owner */
 343                         m_err = EC_NO_WAY;
 344                         return false;
 345                 }
 346
 347                 /* rail transport is possible only on compatible rail types */
 348                 if (IsRailTT()) {
 349                         RailType rail_type = GetTileRailType(m_new_tile);
 350                         if (!HasBit(m_railtypes, rail_type)) {
 351                                 /* incompatible rail type */
 352                                 m_err = EC_RAIL_ROAD_TYPE;
 353                                 return false;
 354                         }
 355                 }
 356
 357                 /* road transport is possible only on compatible road types */
 358                 if (IsRoadTT()) {
 359                         const RoadVehicle *v = RoadVehicle::From(m_veh);
 360                         RoadType roadtype = GetRoadType(m_new_tile, GetRoadTramType(v->roadtype));
 361                         if (!HasBit(v->compatible_roadtypes, roadtype)) {
 362                                 /* incompatible road type */
 363                                 m_err = EC_RAIL_ROAD_TYPE;
 364                                 return false;
 365                         }
 366                 }
 367
 368                 /* tunnel holes and bridge ramps can be entered only from proper direction */
 369                 if (IsTileType(m_new_tile, MP_TUNNELBRIDGE)) {
 370                         if (IsTunnel(m_new_tile)) {
 371                                 if (!m_is_tunnel) {
 372                                         DiagDirection tunnel_enterdir = GetTunnelBridgeDirection(m_new_tile);
 373                                         if (tunnel_enterdir != m_exitdir) {
 374                                                 m_err = EC_NO_WAY;
 375                                                 return false;
 376                                         }
 377                                 }
 378                         } else { // IsBridge(m_new_tile)
 379                                 if (!m_is_bridge) {
 380                                         DiagDirection ramp_enderdir = GetTunnelBridgeDirection(m_new_tile);
 381                                         if (ramp_enderdir != m_exitdir) {
 382                                                 m_err = EC_NO_WAY;
 383                                                 return false;
 384                                         }
 385                                 }
 386                         }
 387                 }
 388
 389                 /* special handling for rail stations - get to the end of platform */
 390                 if (IsRailTT() && m_is_station) {
 391                         /* entered railway station
 392                          * get platform length */
 393                         uint length = BaseStation::GetByTile(m_new_tile)->GetPlatformLength(m_new_tile, TrackdirToExitdir(m_old_td));
 394                         /* how big step we must do to get to the last platform tile; */
 395                         m_tiles_skipped = length - 1;
 396                         /* move to the platform end */
 397                         TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
 398                         diff *= m_tiles_skipped;
 399                         m_new_tile = TILE_ADD(m_new_tile, diff);
 400                         return true;
 401                 }
 402
 403                 return true;
 404         }
 405
 406         /** return true if we must reverse (in depots and single tram bits) */
 407         inline bool ForcedReverse()
 408         {
 409                 /* rail and road depots cause reversing */
 410                 if (!IsWaterTT() && IsDepotTypeTile(m_old_tile, TT())) {
 411                         DiagDirection exitdir = IsRailTT() ? GetRailDepotDirection(m_old_tile) : GetRoadDepotDirection(m_old_tile);
 412                         if (exitdir != m_exitdir) {
 413                                 /* reverse */
 414                                 m_new_tile = m_old_tile;
 415                                 m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
 416                                 m_exitdir = exitdir;
 417                                 m_tiles_skipped = 0;
 418                                 m_is_tunnel = m_is_bridge = m_is_station = false;
 419                                 return true;
 420                         }
 421                 }
 422
 423                 /* Single tram bits and standard road stops cause reversing. */
 424                 if (IsRoadTT() && ((IsTram() && GetSingleTramBit(m_old_tile) == ReverseDiagDir(m_exitdir)) ||
 425                                 (IsStandardRoadStopTile(m_old_tile) && GetRoadStopDir(m_old_tile) == ReverseDiagDir(m_exitdir)))) {
 426                         /* reverse */
 427                         m_new_tile = m_old_tile;
 428                         m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
 429                         m_exitdir = ReverseDiagDir(m_exitdir);
 430                         m_tiles_skipped = 0;
 431                         m_is_tunnel = m_is_bridge = m_is_station = false;
 432                         return true;
 433                 }
 434
 435                 return false;
 436         }
 437
 438         /** return true if we successfully reversed at end of road/track */
 439         inline bool TryReverse()
 440         {
 441                 if (IsRoadTT() && !IsTram()) {
 442                         /* if we reached the end of road, we can reverse the RV and continue moving */
 443                         m_exitdir = ReverseDiagDir(m_exitdir);
 444                         /* new tile will be the same as old one */
 445                         m_new_tile = m_old_tile;
 446                         /* set new trackdir bits to all reachable trackdirs */
 447                         QueryNewTileTrackStatus();
 448                         m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
 449                         if (m_new_td_bits != TRACKDIR_BIT_NONE) {
 450                                 /* we have some trackdirs reachable after reversal */
 451                                 return true;
 452                         }
 453                 }
 454                 m_err = EC_NO_WAY;
 455                 return false;
 456         }
 457
 458 public:
 459         /** Helper for pathfinders - get min/max speed on the m_old_tile/m_old_td */
 460         int GetSpeedLimit(int *pmin_speed = nullptr) const
 461         {
 462                 int min_speed = 0;
 463                 int max_speed = INT_MAX; // no limit
 464
 465                 /* Check for on-bridge speed limit */
 466                 if (!IsWaterTT() && IsBridgeTile(m_old_tile)) {
 467                         int spd = GetBridgeSpec(GetBridgeType(m_old_tile))->speed;
 468                         if (IsRoadTT()) spd *= 2;
 469                         if (max_speed > spd) max_speed = spd;
 470                 }
 471                 /* Check for speed limit imposed by railtype */
 472                 if (IsRailTT()) {
 473                         uint16 rail_speed = GetRailTypeInfo(GetRailType(m_old_tile))->max_speed;
 474                         if (rail_speed > 0) max_speed = min(max_speed, rail_speed);
 475                 }
 476
 477                 /* if min speed was requested, return it */
 478                 if (pmin_speed != nullptr) *pmin_speed = min_speed;
 479                 return max_speed;
 480         }
 481 };
 482
 483 typedef CFollowTrackT<TRANSPORT_WATER, Ship,        true > CFollowTrackWater;
 484 typedef CFollowTrackT<TRANSPORT_ROAD,  RoadVehicle, true > CFollowTrackRoad;
 485 typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       true > CFollowTrackRail;
 486
 487 typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       false> CFollowTrackRailNo90;
 488
 489 typedef CFollowTrackT<TRANSPORT_RAIL, Train, true,  true > CFollowTrackFreeRail;
 490 typedef CFollowTrackT<TRANSPORT_RAIL, Train, false, true > CFollowTrackFreeRailNo90;
 491
 492 #endif /* FOLLOW_TRACK_HPP */