src/pathfinder/follow_track.hpp

   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 follow_track.hpp Template function for track followers */
  11
  12 #ifndef  FOLLOW_TRACK_HPP
  13 #define  FOLLOW_TRACK_HPP
  14
  15 #include "../pbs.h"
  16 #include "../roadveh.h"
  17 #include "../station_base.h"
  18 #include "../train.h"
  19 #include "../tunnelbridge.h"
  20 #include "../tunnelbridge_map.h"
  21 #include "../depot_map.h"
  22 #include "pf_performance_timer.hpp"
  23
  24 /**
  25  * Track follower helper template class (can serve pathfinders and vehicle
  26  *  controllers). See 6 different typedefs below for 3 different transport
  27  *  types w/ or w/o 90-deg turns allowed
  28  */
  29 template <TransportType Ttr_type_, typename VehicleType, bool T90deg_turns_allowed_ = true, bool Tmask_reserved_tracks = false>
  30 struct CFollowTrackT
  31 {
  32         enum ErrorCode {
  33                 EC_NONE,
  34                 EC_OWNER,
  35                 EC_RAIL_TYPE,
  36                 EC_90DEG,
  37                 EC_NO_WAY,
  38                 EC_RESERVED,
  39         };
  40
  41         const VehicleType  *m_veh;           ///< moving vehicle
  42         Owner               m_veh_owner;     ///< owner of the vehicle
  43         TileIndex           m_old_tile;      ///< the origin (vehicle moved from) before move
  44         Trackdir            m_old_td;        ///< the trackdir (the vehicle was on) before move
  45         TileIndex           m_new_tile;      ///< the new tile (the vehicle has entered)
  46         TrackdirBits        m_new_td_bits;   ///< the new set of available trackdirs
  47         DiagDirection       m_exitdir;       ///< exit direction (leaving the old tile)
  48         bool                m_is_tunnel;     ///< last turn passed tunnel
  49         bool                m_is_bridge;     ///< last turn passed bridge ramp
  50         bool                m_is_station;    ///< last turn passed station
  51         int                 m_tiles_skipped; ///< number of skipped tunnel or station tiles
  52         ErrorCode           m_err;
  53         CPerformanceTimer  *m_pPerf;
  54         RailTypes           m_railtypes;
  55
  56         inline CFollowTrackT(const VehicleType *v = NULL, RailTypes railtype_override = INVALID_RAILTYPES, CPerformanceTimer *pPerf = NULL)
  57         {
  58                 Init(v, railtype_override, pPerf);
  59         }
  60
  61         inline CFollowTrackT(Owner o, RailTypes railtype_override = INVALID_RAILTYPES, CPerformanceTimer *pPerf = NULL)
  62         {
  63                 m_veh = NULL;
  64                 Init(o, railtype_override, pPerf);
  65         }
  66
  67         inline void Init(const VehicleType *v, RailTypes railtype_override, CPerformanceTimer *pPerf)
  68         {
  69                 assert(!IsRailTT() || (v != NULL && v->type == VEH_TRAIN));
  70                 m_veh = v;
  71                 Init(v != NULL ? v->owner : INVALID_OWNER, IsRailTT() && railtype_override == INVALID_RAILTYPES ? Train::From(v)->compatible_railtypes : railtype_override, pPerf);
  72         }
  73
  74         inline void Init(Owner o, RailTypes railtype_override, CPerformanceTimer *pPerf)
  75         {
  76                 assert((!IsRoadTT() || m_veh != NULL) && (!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() && HasBit(RoadVehicle::From(m_veh)->compatible_roadtypes, ROADTYPE_TRAM); }
  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, ROADTYPE_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(((TrackStatusToTrackdirBits(GetTileTrackStatus(m_old_tile, TT(), IsRoadTT() ? RoadVehicle::From(m_veh)->compatible_roadtypes : 0)) & TrackdirToTrackdirBits(m_old_td)) != 0) ||
 127                        (IsTram() && GetSingleTramBit(m_old_tile) != INVALID_DIAGDIR)); // Disable the assertion for single tram bits
 128                 m_exitdir = TrackdirToExitdir(m_old_td);
 129                 if (ForcedReverse()) return true;
 130                 if (!CanExitOldTile()) return false;
 131                 FollowTileExit();
 132                 if (!QueryNewTileTrackStatus()) return TryReverse();
 133                 m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
 134                 if (m_new_td_bits == TRACKDIR_BIT_NONE || !CanEnterNewTile()) {
 135                         /* In case we can't enter the next tile, but are
 136                          * a normal road vehicle, then we can actually
 137                          * try to reverse as this is the end of the road.
 138                          * Trams can only turn on the appropriate bits in
 139                          * which case reaching this would mean a dead end
 140                          * near a building and in that case there would
 141                          * a "false" QueryNewTileTrackStatus result and
 142                          * as such reversing is already tried. The fact
 143                          * that function failed can have to do with a
 144                          * missing road bit, or inability to connect the
 145                          * different bits due to slopes. */
 146                         if (IsRoadTT() && !IsTram() && TryReverse()) return true;
 147
 148                         /* CanEnterNewTile already set a reason.
 149                          * Do NOT overwrite it (important for example for EC_RAIL_TYPE).
 150                          * Only set a reason if CanEnterNewTile was not called */
 151                         if (m_new_td_bits == TRACKDIR_BIT_NONE) m_err = EC_NO_WAY;
 152
 153                         return false;
 154                 }
 155                 if (!Allow90degTurns()) {
 156                         m_new_td_bits &= (TrackdirBits)~(int)TrackdirCrossesTrackdirs(m_old_td);
 157                         if (m_new_td_bits == TRACKDIR_BIT_NONE) {
 158                                 m_err = EC_90DEG;
 159                                 return false;
 160                         }
 161                 }
 162                 return true;
 163         }
 164
 165         inline bool MaskReservedTracks()
 166         {
 167                 if (!DoTrackMasking()) return true;
 168
 169                 if (m_is_station) {
 170                         /* Check skipped station tiles as well. */
 171                         TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
 172                         for (TileIndex tile = m_new_tile - diff * m_tiles_skipped; tile != m_new_tile; tile += diff) {
 173                                 if (HasStationReservation(tile)) {
 174                                         m_new_td_bits = TRACKDIR_BIT_NONE;
 175                                         m_err = EC_RESERVED;
 176                                         return false;
 177                                 }
 178                         }
 179                 }
 180
 181                 TrackBits reserved = GetReservedTrackbits(m_new_tile);
 182                 /* Mask already reserved trackdirs. */
 183                 m_new_td_bits &= ~TrackBitsToTrackdirBits(reserved);
 184                 /* Mask out all trackdirs that conflict with the reservation. */
 185                 Track t;
 186                 FOR_EACH_SET_TRACK(t, TrackdirBitsToTrackBits(m_new_td_bits)) {
 187                         if (TracksOverlap(reserved | TrackToTrackBits(t))) m_new_td_bits &= ~TrackToTrackdirBits(t);
 188                 }
 189                 if (m_new_td_bits == TRACKDIR_BIT_NONE) {
 190                         m_err = EC_RESERVED;
 191                         return false;
 192                 }
 193                 return true;
 194         }
 195
 196 protected:
 197         /** Follow the m_exitdir from m_old_tile and fill m_new_tile and m_tiles_skipped */
 198         inline void FollowTileExit()
 199         {
 200                 m_is_station = m_is_bridge = m_is_tunnel = false;
 201                 m_tiles_skipped = 0;
 202
 203                 /* extra handling for tunnels and bridges in our direction */
 204                 if (IsTileType(m_old_tile, MP_TUNNELBRIDGE)) {
 205                         DiagDirection enterdir = GetTunnelBridgeDirection(m_old_tile);
 206                         if (enterdir == m_exitdir) {
 207                                 /* we are entering the tunnel / bridge */
 208                                 if (IsTunnel(m_old_tile)) {
 209                                         m_is_tunnel = true;
 210                                         m_new_tile = GetOtherTunnelEnd(m_old_tile);
 211                                 } else { // IsBridge(m_old_tile)
 212                                         m_is_bridge = true;
 213                                         m_new_tile = GetOtherBridgeEnd(m_old_tile);
 214                                 }
 215                                 m_tiles_skipped = GetTunnelBridgeLength(m_new_tile, m_old_tile);
 216                                 return;
 217                         }
 218                         assert(ReverseDiagDir(enterdir) == m_exitdir);
 219                 }
 220
 221                 /* normal or station tile, do one step */
 222                 TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
 223                 m_new_tile = TILE_ADD(m_old_tile, diff);
 224
 225                 /* special handling for stations */
 226                 if (IsRailTT() && HasStationTileRail(m_new_tile)) {
 227                         m_is_station = true;
 228                 } else if (IsRoadTT() && IsRoadStopTile(m_new_tile)) {
 229                         m_is_station = true;
 230                 } else {
 231                         m_is_station = false;
 232                 }
 233         }
 234
 235         /** stores track status (available trackdirs) for the new tile into m_new_td_bits */
 236         inline bool QueryNewTileTrackStatus()
 237         {
 238                 CPerfStart perf(*m_pPerf);
 239                 if (IsRailTT() && IsPlainRailTile(m_new_tile)) {
 240                         m_new_td_bits = (TrackdirBits)(GetTrackBits(m_new_tile) * 0x101);
 241                 } else {
 242                         m_new_td_bits = TrackStatusToTrackdirBits(GetTileTrackStatus(m_new_tile, TT(), IsRoadTT() ? RoadVehicle::From(m_veh)->compatible_roadtypes : 0));
 243
 244                         if (IsTram() && m_new_td_bits == 0) {
 245                                 /* GetTileTrackStatus() returns 0 for single tram bits.
 246                                  * As we cannot change it there (easily) without breaking something, change it here */
 247                                 switch (GetSingleTramBit(m_new_tile)) {
 248                                         case DIAGDIR_NE:
 249                                         case DIAGDIR_SW:
 250                                                 m_new_td_bits = TRACKDIR_BIT_X_NE | TRACKDIR_BIT_X_SW;
 251                                                 break;
 252
 253                                         case DIAGDIR_NW:
 254                                         case DIAGDIR_SE:
 255                                                 m_new_td_bits = TRACKDIR_BIT_Y_NW | TRACKDIR_BIT_Y_SE;
 256                                                 break;
 257
 258                                         default: break;
 259                                 }
 260                         }
 261                 }
 262                 return (m_new_td_bits != TRACKDIR_BIT_NONE);
 263         }
 264
 265         /** return true if we can leave m_old_tile in m_exitdir */
 266         inline bool CanExitOldTile()
 267         {
 268                 /* road stop can be left at one direction only unless it's a drive-through stop */
 269                 if (IsRoadTT() && IsStandardRoadStopTile(m_old_tile)) {
 270                         DiagDirection exitdir = GetRoadStopDir(m_old_tile);
 271                         if (exitdir != m_exitdir) {
 272                                 m_err = EC_NO_WAY;
 273                                 return false;
 274                         }
 275                 }
 276
 277                 /* single tram bits can only be left in one direction */
 278                 if (IsTram()) {
 279                         DiagDirection single_tram = GetSingleTramBit(m_old_tile);
 280                         if (single_tram != INVALID_DIAGDIR && single_tram != m_exitdir) {
 281                                 m_err = EC_NO_WAY;
 282                                 return false;
 283                         }
 284                 }
 285
 286                 /* road depots can be also left in one direction only */
 287                 if (IsRoadTT() && IsDepotTypeTile(m_old_tile, TT())) {
 288                         DiagDirection exitdir = GetRoadDepotDirection(m_old_tile);
 289                         if (exitdir != m_exitdir) {
 290                                 m_err = EC_NO_WAY;
 291                                 return false;
 292                         }
 293                 }
 294                 return true;
 295         }
 296
 297         /** return true if we can enter m_new_tile from m_exitdir */
 298         inline bool CanEnterNewTile()
 299         {
 300                 if (IsRoadTT() && IsStandardRoadStopTile(m_new_tile)) {
 301                         /* road stop can be entered from one direction only unless it's a drive-through stop */
 302                         DiagDirection exitdir = GetRoadStopDir(m_new_tile);
 303                         if (ReverseDiagDir(exitdir) != m_exitdir) {
 304                                 m_err = EC_NO_WAY;
 305                                 return false;
 306                         }
 307                 }
 308
 309                 /* single tram bits can only be entered from one direction */
 310                 if (IsTram()) {
 311                         DiagDirection single_tram = GetSingleTramBit(m_new_tile);
 312                         if (single_tram != INVALID_DIAGDIR && single_tram != ReverseDiagDir(m_exitdir)) {
 313                                 m_err = EC_NO_WAY;
 314                                 return false;
 315                         }
 316                 }
 317
 318                 /* road and rail depots can also be entered from one direction only */
 319                 if (IsRoadTT() && IsDepotTypeTile(m_new_tile, TT())) {
 320                         DiagDirection exitdir = GetRoadDepotDirection(m_new_tile);
 321                         if (ReverseDiagDir(exitdir) != m_exitdir) {
 322                                 m_err = EC_NO_WAY;
 323                                 return false;
 324                         }
 325                         /* don't try to enter other company's depots */
 326                         if (GetTileOwner(m_new_tile) != m_veh_owner) {
 327                                 m_err = EC_OWNER;
 328                                 return false;
 329                         }
 330                 }
 331                 if (IsRailTT() && IsDepotTypeTile(m_new_tile, TT())) {
 332                         DiagDirection exitdir = GetRailDepotDirection(m_new_tile);
 333                         if (ReverseDiagDir(exitdir) != m_exitdir) {
 334                                 m_err = EC_NO_WAY;
 335                                 return false;
 336                         }
 337                 }
 338
 339                 /* rail transport is possible only on tiles with the same owner as vehicle */
 340                 if (IsRailTT() && GetTileOwner(m_new_tile) != m_veh_owner) {
 341                         /* different owner */
 342                         m_err = EC_NO_WAY;
 343                         return false;
 344                 }
 345
 346                 /* rail transport is possible only on compatible rail types */
 347                 if (IsRailTT()) {
 348                         RailType rail_type = GetTileRailType(m_new_tile);
 349                         if (!HasBit(m_railtypes, rail_type)) {
 350                                 /* incompatible rail type */
 351                                 m_err = EC_RAIL_TYPE;
 352                                 return false;
 353                         }
 354                 }
 355
 356                 /* tunnel holes and bridge ramps can be entered only from proper direction */
 357                 if (IsTileType(m_new_tile, MP_TUNNELBRIDGE)) {
 358                         if (IsTunnel(m_new_tile)) {
 359                                 if (!m_is_tunnel) {
 360                                         DiagDirection tunnel_enterdir = GetTunnelBridgeDirection(m_new_tile);
 361                                         if (tunnel_enterdir != m_exitdir) {
 362                                                 m_err = EC_NO_WAY;
 363                                                 return false;
 364                                         }
 365                                 }
 366                         } else { // IsBridge(m_new_tile)
 367                                 if (!m_is_bridge) {
 368                                         DiagDirection ramp_enderdir = GetTunnelBridgeDirection(m_new_tile);
 369                                         if (ramp_enderdir != m_exitdir) {
 370                                                 m_err = EC_NO_WAY;
 371                                                 return false;
 372                                         }
 373                                 }
 374                         }
 375                 }
 376
 377                 /* special handling for rail stations - get to the end of platform */
 378                 if (IsRailTT() && m_is_station) {
 379                         /* entered railway station
 380                          * get platform length */
 381                         uint length = BaseStation::GetByTile(m_new_tile)->GetPlatformLength(m_new_tile, TrackdirToExitdir(m_old_td));
 382                         /* how big step we must do to get to the last platform tile; */
 383                         m_tiles_skipped = length - 1;
 384                         /* move to the platform end */
 385                         TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
 386                         diff *= m_tiles_skipped;
 387                         m_new_tile = TILE_ADD(m_new_tile, diff);
 388                         return true;
 389                 }
 390
 391                 return true;
 392         }
 393
 394         /** return true if we must reverse (in depots and single tram bits) */
 395         inline bool ForcedReverse()
 396         {
 397                 /* rail and road depots cause reversing */
 398                 if (!IsWaterTT() && IsDepotTypeTile(m_old_tile, TT())) {
 399                         DiagDirection exitdir = IsRailTT() ? GetRailDepotDirection(m_old_tile) : GetRoadDepotDirection(m_old_tile);
 400                         if (exitdir != m_exitdir) {
 401                                 /* reverse */
 402                                 m_new_tile = m_old_tile;
 403                                 m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
 404                                 m_exitdir = exitdir;
 405                                 m_tiles_skipped = 0;
 406                                 m_is_tunnel = m_is_bridge = m_is_station = false;
 407                                 return true;
 408                         }
 409                 }
 410
 411                 /* single tram bits cause reversing */
 412                 if (IsTram() && GetSingleTramBit(m_old_tile) == ReverseDiagDir(m_exitdir)) {
 413                         /* reverse */
 414                         m_new_tile = m_old_tile;
 415                         m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
 416                         m_exitdir = ReverseDiagDir(m_exitdir);
 417                         m_tiles_skipped = 0;
 418                         m_is_tunnel = m_is_bridge = m_is_station = false;
 419                         return true;
 420                 }
 421
 422                 return false;
 423         }
 424
 425         /** return true if we successfully reversed at end of road/track */
 426         inline bool TryReverse()
 427         {
 428                 if (IsRoadTT() && !IsTram()) {
 429                         /* if we reached the end of road, we can reverse the RV and continue moving */
 430                         m_exitdir = ReverseDiagDir(m_exitdir);
 431                         /* new tile will be the same as old one */
 432                         m_new_tile = m_old_tile;
 433                         /* set new trackdir bits to all reachable trackdirs */
 434                         QueryNewTileTrackStatus();
 435                         m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
 436                         if (m_new_td_bits != TRACKDIR_BIT_NONE) {
 437                                 /* we have some trackdirs reachable after reversal */
 438                                 return true;
 439                         }
 440                 }
 441                 m_err = EC_NO_WAY;
 442                 return false;
 443         }
 444
 445 public:
 446         /** Helper for pathfinders - get min/max speed on the m_old_tile/m_old_td */
 447         int GetSpeedLimit(int *pmin_speed = NULL) const
 448         {
 449                 int min_speed = 0;
 450                 int max_speed = INT_MAX; // no limit
 451
 452                 /* Check for on-bridge speed limit */
 453                 if (!IsWaterTT() && IsBridgeTile(m_old_tile)) {
 454                         int spd = GetBridgeSpec(GetBridgeType(m_old_tile))->speed;
 455                         if (IsRoadTT()) spd *= 2;
 456                         if (max_speed > spd) max_speed = spd;
 457                 }
 458                 /* Check for speed limit imposed by railtype */
 459                 if (IsRailTT()) {
 460                         uint16 rail_speed = GetRailTypeInfo(GetRailType(m_old_tile))->max_speed;
 461                         if (rail_speed > 0) max_speed = min(max_speed, rail_speed);
 462                 }
 463
 464                 /* if min speed was requested, return it */
 465                 if (pmin_speed != NULL) *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_WATER, Ship,        false> CFollowTrackWaterNo90;
 475 typedef CFollowTrackT<TRANSPORT_ROAD,  RoadVehicle, false> CFollowTrackRoadNo90;
 476 typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       false> CFollowTrackRailNo90;
 477
 478 typedef CFollowTrackT<TRANSPORT_RAIL, Train, true,  true > CFollowTrackFreeRail;
 479 typedef CFollowTrackT<TRANSPORT_RAIL, Train, false, true > CFollowTrackFreeRailNo90;
 480
 481 #endif /* FOLLOW_TRACK_HPP */