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 *veh; ///< moving vehicle
  40         Owner veh_owner; ///< owner of the vehicle
  41         TileIndex old_tile; ///< the origin (vehicle moved from) before move
  42         Trackdir old_td; ///< the trackdir (the vehicle was on) before move
  43         TileIndex new_tile; ///< the new tile (the vehicle has entered)
  44         TrackdirBits new_td_bits; ///< the new set of available trackdirs
  45         DiagDirection exitdir; ///< exit direction (leaving the old tile)
  46         bool is_tunnel; ///< last turn passed tunnel
  47         bool is_bridge; ///< last turn passed bridge ramp
  48         bool is_station; ///< last turn passed station
  49         int tiles_skipped; ///< number of skipped tunnel or station tiles
  50         ErrorCode err;
  51         RailTypes 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                 this->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                 this->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() || this->veh != nullptr);
  75                 assert(!IsRailTT() || railtype_override != INVALID_RAILTYPES);
  76                 this->veh_owner = o;
  77                 /* don't worry, all is inlined so compiler should remove unnecessary initializations */
  78                 this->old_tile = INVALID_TILE;
  79                 this->old_td = INVALID_TRACKDIR;
  80                 this->new_tile = INVALID_TILE;
  81                 this->new_td_bits = TRACKDIR_BIT_NONE;
  82                 this->exitdir = INVALID_DIAGDIR;
  83                 this->is_station = false;
  84                 this->is_bridge = false;
  85                 this->is_tunnel = false;
  86                 this->tiles_skipped = 0;
  87                 this->err = EC_NONE;
  88                 this->railtypes = railtype_override;
  89         }
  90
  91         debug_inline static TransportType TT() { return Ttr_type_; }
  92         debug_inline static bool IsWaterTT() { return TT() == TRANSPORT_WATER; }
  93         debug_inline static bool IsRailTT() { return TT() == TRANSPORT_RAIL; }
  94         inline bool IsTram() { return IsRoadTT() && RoadTypeIsTram(RoadVehicle::From(this->veh)->roadtype); }
  95         debug_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(this->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                 this->old_tile = old_tile;
 124                 this->old_td = old_td;
 125                 this->err = EC_NONE;
 126
 127                 assert([&]() {
 128                         if (this->IsTram() && this->GetSingleTramBit(this->old_tile) != INVALID_DIAGDIR) return true; // Skip the check for single tram bits
 129                         const uint sub_mode = (IsRoadTT() && this->veh != nullptr) ? (this->IsTram() ? RTT_TRAM : RTT_ROAD) : 0;
 130                         const TrackdirBits old_tile_valid_dirs = TrackStatusToTrackdirBits(GetTileTrackStatus(this->old_tile, TT(), sub_mode));
 131                         return (old_tile_valid_dirs & TrackdirToTrackdirBits(this->old_td)) != TRACKDIR_BIT_NONE;
 132                 }());
 133
 134                 this->exitdir = TrackdirToExitdir(this->old_td);
 135                 if (this->ForcedReverse()) return true;
 136                 if (!this->CanExitOldTile()) return false;
 137                 this->FollowTileExit();
 138                 if (!this->QueryNewTileTrackStatus()) return TryReverse();
 139                 this->new_td_bits &= DiagdirReachesTrackdirs(this->exitdir);
 140                 if (this->new_td_bits == TRACKDIR_BIT_NONE || !this->CanEnterNewTile()) {
 141                         /* In case we can't enter the next tile, but are
 142                          * a normal road vehicle, then we can actually
 143                          * try to reverse as this is the end of the road.
 144                          * Trams can only turn on the appropriate bits in
 145                          * which case reaching this would mean a dead end
 146                          * near a building and in that case there would
 147                          * a "false" QueryNewTileTrackStatus result and
 148                          * as such reversing is already tried. The fact
 149                          * that function failed can have to do with a
 150                          * missing road bit, or inability to connect the
 151                          * different bits due to slopes. */
 152                         if (IsRoadTT() && !this->IsTram() && this->TryReverse()) return true;
 153
 154                         /* CanEnterNewTile already set a reason.
 155                          * Do NOT overwrite it (important for example for EC_RAIL_ROAD_TYPE).
 156                          * Only set a reason if CanEnterNewTile was not called */
 157                         if (this->new_td_bits == TRACKDIR_BIT_NONE) this->err = EC_NO_WAY;
 158
 159                         return false;
 160                 }
 161                 if ((!IsRailTT() && !Allow90degTurns()) || (IsRailTT() && Rail90DegTurnDisallowed(GetTileRailType(this->old_tile), GetTileRailType(this->new_tile), !Allow90degTurns()))) {
 162                         this->new_td_bits &= (TrackdirBits)~(int)TrackdirCrossesTrackdirs(this->old_td);
 163                         if (this->new_td_bits == TRACKDIR_BIT_NONE) {
 164                                 this->err = EC_90DEG;
 165                                 return false;
 166                         }
 167                 }
 168                 return true;
 169         }
 170
 171         inline bool MaskReservedTracks()
 172         {
 173                 if (!DoTrackMasking()) return true;
 174
 175                 if (this->is_station) {
 176                         /* Check skipped station tiles as well. */
 177                         TileIndexDiff diff = TileOffsByDiagDir(this->exitdir);
 178                         for (TileIndex tile = this->new_tile - diff * this->tiles_skipped; tile != this->new_tile; tile += diff) {
 179                                 if (HasStationReservation(tile)) {
 180                                         this->new_td_bits = TRACKDIR_BIT_NONE;
 181                                         this->err = EC_RESERVED;
 182                                         return false;
 183                                 }
 184                         }
 185                 }
 186
 187                 TrackBits reserved = GetReservedTrackbits(this->new_tile);
 188                 /* Mask already reserved trackdirs. */
 189                 this->new_td_bits &= ~TrackBitsToTrackdirBits(reserved);
 190                 /* Mask out all trackdirs that conflict with the reservation. */
 191                 for (Track t : SetTrackBitIterator(TrackdirBitsToTrackBits(this->new_td_bits))) {
 192                         if (TracksOverlap(reserved | TrackToTrackBits(t))) this->new_td_bits &= ~TrackToTrackdirBits(t);
 193                 }
 194                 if (this->new_td_bits == TRACKDIR_BIT_NONE) {
 195                         this->err = EC_RESERVED;
 196                         return false;
 197                 }
 198                 return true;
 199         }
 200
 201 protected:
 202         /** Follow the exitdir from old_tile and fill new_tile and tiles_skipped */
 203         inline void FollowTileExit()
 204         {
 205                 this->is_station = false;
 206                 this->is_bridge = false;
 207                 this->is_tunnel = false;
 208                 this->tiles_skipped = 0;
 209
 210                 /* extra handling for tunnels and bridges in our direction */
 211                 if (IsTileType(this->old_tile, MP_TUNNELBRIDGE)) {
 212                         DiagDirection enterdir = GetTunnelBridgeDirection(this->old_tile);
 213                         if (enterdir == this->exitdir) {
 214                                 /* we are entering the tunnel / bridge */
 215                                 if (IsTunnel(this->old_tile)) {
 216                                         this->is_tunnel = true;
 217                                         this->new_tile = GetOtherTunnelEnd(this->old_tile);
 218                                 } else { // IsBridge(old_tile)
 219                                         this->is_bridge = true;
 220                                         this->new_tile = GetOtherBridgeEnd(this->old_tile);
 221                                 }
 222                                 this->tiles_skipped = GetTunnelBridgeLength(this->new_tile, this->old_tile);
 223                                 return;
 224                         }
 225                         assert(ReverseDiagDir(enterdir) == this->exitdir);
 226                 }
 227
 228                 /* normal or station tile, do one step */
 229                 this->new_tile = TileAddByDiagDir(this->old_tile, this->exitdir);
 230
 231                 /* special handling for stations */
 232                 if (IsRailTT() && HasStationTileRail(this->new_tile)) {
 233                         this->is_station = true;
 234                 } else if (IsRoadTT() && IsStationRoadStopTile(this->new_tile)) {
 235                         this->is_station = true;
 236                 }
 237         }
 238
 239         /** stores track status (available trackdirs) for the new tile into new_td_bits */
 240         inline bool QueryNewTileTrackStatus()
 241         {
 242                 if (IsRailTT() && IsPlainRailTile(this->new_tile)) {
 243                         this->new_td_bits = (TrackdirBits)(GetTrackBits(this->new_tile) * 0x101);
 244                 } else if (IsRoadTT()) {
 245                         this->new_td_bits = GetTrackdirBitsForRoad(this->new_tile, this->IsTram() ? RTT_TRAM : RTT_ROAD);
 246                 } else {
 247                         this->new_td_bits = TrackStatusToTrackdirBits(GetTileTrackStatus(this->new_tile, TT(), 0));
 248                 }
 249                 return (this->new_td_bits != TRACKDIR_BIT_NONE);
 250         }
 251
 252         /** return true if we can leave old_tile in exitdir */
 253         inline bool CanExitOldTile()
 254         {
 255                 /* road stop can be left at one direction only unless it's a drive-through stop */
 256                 if (IsRoadTT() && IsBayRoadStopTile(this->old_tile)) {
 257                         DiagDirection exitdir = GetBayRoadStopDir(this->old_tile);
 258                         if (exitdir != this->exitdir) {
 259                                 this->err = EC_NO_WAY;
 260                                 return false;
 261                         }
 262                 }
 263
 264                 /* single tram bits can only be left in one direction */
 265                 if (this->IsTram()) {
 266                         DiagDirection single_tram = GetSingleTramBit(this->old_tile);
 267                         if (single_tram != INVALID_DIAGDIR && single_tram != this->exitdir) {
 268                                 this->err = EC_NO_WAY;
 269                                 return false;
 270                         }
 271                 }
 272
 273                 /* road depots can be also left in one direction only */
 274                 if (IsRoadTT() && IsDepotTypeTile(this->old_tile, TT())) {
 275                         DiagDirection exitdir = GetRoadDepotDirection(this->old_tile);
 276                         if (exitdir != this->exitdir) {
 277                                 this->err = EC_NO_WAY;
 278                                 return false;
 279                         }
 280                 }
 281                 return true;
 282         }
 283
 284         /** return true if we can enter new_tile from exitdir */
 285         inline bool CanEnterNewTile()
 286         {
 287                 if (IsRoadTT() && IsBayRoadStopTile(this->new_tile)) {
 288                         /* road stop can be entered from one direction only unless it's a drive-through stop */
 289                         DiagDirection exitdir = GetBayRoadStopDir(this->new_tile);
 290                         if (ReverseDiagDir(exitdir) != this->exitdir) {
 291                                 this->err = EC_NO_WAY;
 292                                 return false;
 293                         }
 294                 }
 295
 296                 /* single tram bits can only be entered from one direction */
 297                 if (this->IsTram()) {
 298                         DiagDirection single_tram = this->GetSingleTramBit(this->new_tile);
 299                         if (single_tram != INVALID_DIAGDIR && single_tram != ReverseDiagDir(this->exitdir)) {
 300                                 this->err = EC_NO_WAY;
 301                                 return false;
 302                         }
 303                 }
 304
 305                 /* road and rail depots can also be entered from one direction only */
 306                 if (IsRoadTT() && IsDepotTypeTile(this->new_tile, TT())) {
 307                         DiagDirection exitdir = GetRoadDepotDirection(this->new_tile);
 308                         if (ReverseDiagDir(exitdir) != this->exitdir) {
 309                                 this->err = EC_NO_WAY;
 310                                 return false;
 311                         }
 312                         /* don't try to enter other company's depots */
 313                         if (GetTileOwner(this->new_tile) != this->veh_owner) {
 314                                 this->err = EC_OWNER;
 315                                 return false;
 316                         }
 317                 }
 318                 if (IsRailTT() && IsDepotTypeTile(this->new_tile, TT())) {
 319                         DiagDirection exitdir = GetRailDepotDirection(this->new_tile);
 320                         if (ReverseDiagDir(exitdir) != this->exitdir) {
 321                                 this->err = EC_NO_WAY;
 322                                 return false;
 323                         }
 324                 }
 325
 326                 /* rail transport is possible only on tiles with the same owner as vehicle */
 327                 if (IsRailTT() && GetTileOwner(this->new_tile) != this->veh_owner) {
 328                         /* different owner */
 329                         this->err = EC_NO_WAY;
 330                         return false;
 331                 }
 332
 333                 /* rail transport is possible only on compatible rail types */
 334                 if (IsRailTT()) {
 335                         RailType rail_type = GetTileRailType(this->new_tile);
 336                         if (!HasBit(this->railtypes, rail_type)) {
 337                                 /* incompatible rail type */
 338                                 this->err = EC_RAIL_ROAD_TYPE;
 339                                 return false;
 340                         }
 341                 }
 342
 343                 /* road transport is possible only on compatible road types */
 344                 if (IsRoadTT()) {
 345                         const RoadVehicle *v = RoadVehicle::From(this->veh);
 346                         RoadType roadtype = GetRoadType(this->new_tile, GetRoadTramType(v->roadtype));
 347                         if (!HasBit(v->compatible_roadtypes, roadtype)) {
 348                                 /* incompatible road type */
 349                                 this->err = EC_RAIL_ROAD_TYPE;
 350                                 return false;
 351                         }
 352                 }
 353
 354                 /* tunnel holes and bridge ramps can be entered only from proper direction */
 355                 if (IsTileType(this->new_tile, MP_TUNNELBRIDGE)) {
 356                         if (IsTunnel(this->new_tile)) {
 357                                 if (!this->is_tunnel) {
 358                                         DiagDirection tunnel_enterdir = GetTunnelBridgeDirection(this->new_tile);
 359                                         if (tunnel_enterdir != this->exitdir) {
 360                                                 this->err = EC_NO_WAY;
 361                                                 return false;
 362                                         }
 363                                 }
 364                         } else { // IsBridge(new_tile)
 365                                 if (!this->is_bridge) {
 366                                         DiagDirection ramp_enderdir = GetTunnelBridgeDirection(this->new_tile);
 367                                         if (ramp_enderdir != this->exitdir) {
 368                                                 this->err = EC_NO_WAY;
 369                                                 return false;
 370                                         }
 371                                 }
 372                         }
 373                 }
 374
 375                 /* special handling for rail stations - get to the end of platform */
 376                 if (IsRailTT() && this->is_station) {
 377                         /* entered railway station
 378                          * get platform length */
 379                         uint length = BaseStation::GetByTile(this->new_tile)->GetPlatformLength(this->new_tile, TrackdirToExitdir(this->old_td));
 380                         /* how big step we must do to get to the last platform tile? */
 381                         this->tiles_skipped = length - 1;
 382                         /* move to the platform end */
 383                         TileIndexDiff diff = TileOffsByDiagDir(this->exitdir);
 384                         diff *= this->tiles_skipped;
 385                         this->new_tile = TileAdd(this->new_tile, diff);
 386                         return true;
 387                 }
 388
 389                 return true;
 390         }
 391
 392         /** return true if we must reverse (in depots and single tram bits) */
 393         inline bool ForcedReverse()
 394         {
 395                 /* rail and road depots cause reversing */
 396                 if (!IsWaterTT() && IsDepotTypeTile(this->old_tile, TT())) {
 397                         DiagDirection exitdir = IsRailTT() ? GetRailDepotDirection(this->old_tile) : GetRoadDepotDirection(this->old_tile);
 398                         if (exitdir != this->exitdir) {
 399                                 /* reverse */
 400                                 this->new_tile = this->old_tile;
 401                                 this->new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(this->old_td));
 402                                 this->exitdir = exitdir;
 403                                 this->tiles_skipped = 0;
 404                                 this->is_tunnel = false;
 405                                 this->is_bridge = false;
 406                                 this->is_station = false;
 407                                 return true;
 408                         }
 409                 }
 410
 411                 /* Single tram bits and standard road stops cause reversing. */
 412                 if (IsRoadTT() && ((this->IsTram() && GetSingleTramBit(this->old_tile) == ReverseDiagDir(this->exitdir)) ||
 413                                 (IsBayRoadStopTile(this->old_tile) && GetBayRoadStopDir(this->old_tile) == ReverseDiagDir(this->exitdir)))) {
 414                         /* reverse */
 415                         this->new_tile = this->old_tile;
 416                         this->new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(this->old_td));
 417                         this->exitdir = ReverseDiagDir(this->exitdir);
 418                         this->tiles_skipped = 0;
 419                         this->is_tunnel = false;
 420                         this->is_bridge = false;
 421                         this->is_station = false;
 422                         return true;
 423                 }
 424
 425                 return false;
 426         }
 427
 428         /** return true if we successfully reversed at end of road/track */
 429         inline bool TryReverse()
 430         {
 431                 if (IsRoadTT() && !this->IsTram()) {
 432                         /* if we reached the end of road, we can reverse the RV and continue moving */
 433                         this->exitdir = ReverseDiagDir(this->exitdir);
 434                         /* new tile will be the same as old one */
 435                         this->new_tile = this->old_tile;
 436                         /* set new trackdir bits to all reachable trackdirs */
 437                         QueryNewTileTrackStatus();
 438                         this->new_td_bits &= DiagdirReachesTrackdirs(this->exitdir);
 439                         if (this->new_td_bits != TRACKDIR_BIT_NONE) {
 440                                 /* we have some trackdirs reachable after reversal */
 441                                 return true;
 442                         }
 443                 }
 444                 this->err = EC_NO_WAY;
 445                 return false;
 446         }
 447
 448 public:
 449         /** Helper for pathfinders - get min/max speed on the old_tile/old_td */
 450         int GetSpeedLimit(int *pmin_speed = nullptr) const
 451         {
 452                 int min_speed = 0;
 453                 int max_speed = INT_MAX; // no limit
 454
 455                 /* Check for on-bridge speed limit */
 456                 if (!IsWaterTT() && IsBridgeTile(this->old_tile)) {
 457                         int spd = GetBridgeSpec(GetBridgeType(this->old_tile))->speed;
 458                         if (IsRoadTT()) spd *= 2;
 459                         max_speed = std::min(max_speed, spd);
 460                 }
 461                 /* Check for speed limit imposed by railtype */
 462                 if (IsRailTT()) {
 463                         uint16_t rail_speed = GetRailTypeInfo(GetRailType(this->old_tile))->max_speed;
 464                         if (rail_speed > 0) max_speed = std::min<int>(max_speed, rail_speed);
 465                 }
 466                 if (IsRoadTT()) {
 467                         /* max_speed is already in roadvehicle units, no need to further modify (divide by 2) */
 468                         uint16_t road_speed = GetRoadTypeInfo(GetRoadType(this->old_tile, GetRoadTramType(RoadVehicle::From(this->veh)->roadtype)))->max_speed;
 469                         if (road_speed > 0) max_speed = std::min<int>(max_speed, road_speed);
 470                 }
 471
 472                 /* if min speed was requested, return it */
 473                 if (pmin_speed != nullptr) *pmin_speed = min_speed;
 474                 return max_speed;
 475         }
 476 };
 477
 478 typedef CFollowTrackT<TRANSPORT_WATER, Ship,        true > CFollowTrackWater;
 479 typedef CFollowTrackT<TRANSPORT_ROAD,  RoadVehicle, true > CFollowTrackRoad;
 480 typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       true > CFollowTrackRail;
 481
 482 typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       false> CFollowTrackRailNo90;
 483
 484 typedef CFollowTrackT<TRANSPORT_RAIL, Train, true,  true > CFollowTrackFreeRail;
 485 typedef CFollowTrackT<TRANSPORT_RAIL, Train, false, true > CFollowTrackFreeRailNo90;
 486
 487 #endif /* FOLLOW_TRACK_HPP */