# follow_track.hpp

Go to the documentation of this file.

    00001 /* $Id: follow_track.hpp 26109 2013-11-25 14:34:09Z rubidium $ */
    00002
    00003 /*
    00004  * This file is part of OpenTTD.
    00005  * 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.
    00006  * 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.
    00007  * 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/>.
    00008  */
    00009
    00012 #ifndef  FOLLOW_TRACK_HPP
    00013 #define  FOLLOW_TRACK_HPP
    00014
    00015 #include "../pbs.h"
    00016 #include "../roadveh.h"
    00017 #include "../station_base.h"
    00018 #include "../train.h"
    00019 #include "../tunnelbridge.h"
    00020 #include "../tunnelbridge_map.h"
    00021 #include "../depot_map.h"
    00022 #include "pf_performance_timer.hpp"
    00023
    00029 template <TransportType Ttr_type_, typename VehicleType, bool T90deg_turns_allowed_ = true, bool Tmask_reserved_tracks = false>
    00030 struct CFollowTrackT
    00031 {
    00032   enum ErrorCode {
    00033     EC_NONE,
    00034     EC_OWNER,
    00035     EC_RAIL_TYPE,
    00036     EC_90DEG,
    00037     EC_NO_WAY,
    00038     EC_RESERVED,
    00039   };
    00040
    00041   const VehicleType  *m_veh;
    00042   Owner               m_veh_owner;
    00043   TileIndex           m_old_tile;
    00044   Trackdir            m_old_td;
    00045   TileIndex           m_new_tile;
    00046   TrackdirBits        m_new_td_bits;
    00047   DiagDirection       m_exitdir;
    00048   bool                m_is_tunnel;
    00049   bool                m_is_bridge;
    00050   bool                m_is_station;
    00051   int                 m_tiles_skipped;
    00052   ErrorCode           m_err;
    00053   CPerformanceTimer  *m_pPerf;
    00054   RailTypes           m_railtypes;
    00055
    00056   inline CFollowTrackT(const VehicleType *v = NULL, RailTypes railtype_override = INVALID_RAILTYPES, CPerformanceTimer *pPerf = NULL)
    00057   {
    00058     Init(v, railtype_override, pPerf);
    00059   }
    00060
    00061   inline CFollowTrackT(Owner o, RailTypes railtype_override = INVALID_RAILTYPES, CPerformanceTimer *pPerf = NULL)
    00062   {
    00063     m_veh = NULL;
    00064     Init(o, railtype_override, pPerf);
    00065   }
    00066
    00067   inline void Init(const VehicleType *v, RailTypes railtype_override, CPerformanceTimer *pPerf)
    00068   {
    00069     assert(!IsRailTT() || (v != NULL && v->type == VEH_TRAIN));
    00070     m_veh = v;
    00071     Init(v != NULL ? v->owner : INVALID_OWNER, IsRailTT() && railtype_override == INVALID_RAILTYPES ? Train::From(v)->compatible_railtypes : railtype_override, pPerf);
    00072   }
    00073
    00074   inline void Init(Owner o, RailTypes railtype_override, CPerformanceTimer *pPerf)
    00075   {
    00076     assert((!IsRoadTT() || m_veh != NULL) && (!IsRailTT() || railtype_override != INVALID_RAILTYPES));
    00077     m_veh_owner = o;
    00078     m_pPerf = pPerf;
    00079     /* don't worry, all is inlined so compiler should remove unnecessary initializations */
    00080     m_old_tile = INVALID_TILE;
    00081     m_old_td = INVALID_TRACKDIR;
    00082     m_new_tile = INVALID_TILE;
    00083     m_new_td_bits = TRACKDIR_BIT_NONE;
    00084     m_exitdir = INVALID_DIAGDIR;
    00085     m_is_station = m_is_bridge = m_is_tunnel = false;
    00086     m_tiles_skipped = 0;
    00087     m_err = EC_NONE;
    00088     m_railtypes = railtype_override;
    00089   }
    00090
    00091   inline static TransportType TT() { return Ttr_type_; }
    00092   inline static bool IsWaterTT() { return TT() == TRANSPORT_WATER; }
    00093   inline static bool IsRailTT() { return TT() == TRANSPORT_RAIL; }
    00094   inline bool IsTram() { return IsRoadTT() && HasBit(RoadVehicle::From(m_veh)->compatible_roadtypes, ROADTYPE_TRAM); }
    00095   inline static bool IsRoadTT() { return TT() == TRANSPORT_ROAD; }
    00096   inline static bool Allow90degTurns() { return T90deg_turns_allowed_; }
    00097   inline static bool DoTrackMasking() { return Tmask_reserved_tracks; }
    00098
    00100   inline DiagDirection GetSingleTramBit(TileIndex tile)
    00101   {
    00102     assert(IsTram()); // this function shouldn't be called in other cases
    00103
    00104     if (IsNormalRoadTile(tile)) {
    00105       RoadBits rb = GetRoadBits(tile, ROADTYPE_TRAM);
    00106       switch (rb) {
    00107         case ROAD_NW: return DIAGDIR_NW;
    00108         case ROAD_SW: return DIAGDIR_SW;
    00109         case ROAD_SE: return DIAGDIR_SE;
    00110         case ROAD_NE: return DIAGDIR_NE;
    00111         default: break;
    00112       }
    00113     }
    00114     return INVALID_DIAGDIR;
    00115   }
    00116
    00121   inline bool Follow(TileIndex old_tile, Trackdir old_td)
    00122   {
    00123     m_old_tile = old_tile;
    00124     m_old_td = old_td;
    00125     m_err = EC_NONE;
    00126     assert(((TrackStatusToTrackdirBits(GetTileTrackStatus(m_old_tile, TT(), IsRoadTT() ? RoadVehicle::From(m_veh)->compatible_roadtypes : 0)) & TrackdirToTrackdirBits(m_old_td)) != 0) ||
    00127            (IsTram() && GetSingleTramBit(m_old_tile) != INVALID_DIAGDIR)); // Disable the assertion for single tram bits
    00128     m_exitdir = TrackdirToExitdir(m_old_td);
    00129     if (ForcedReverse()) return true;
    00130     if (!CanExitOldTile()) return false;
    00131     FollowTileExit();
    00132     if (!QueryNewTileTrackStatus()) return TryReverse();
    00133     if (!CanEnterNewTile()) return false;
    00134     m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
    00135     if (m_new_td_bits == TRACKDIR_BIT_NONE) {
    00136       /* In case we can't enter the next tile, but are
    00137        * a normal road vehicle, then we can actually
    00138        * try to reverse as this is the end of the road.
    00139        * Trams can only turn on the appropriate bits in
    00140        * which case reaching this would mean a dead end
    00141        * near a building and in that case there would
    00142        * a "false" QueryNewTileTrackStatus result and
    00143        * as such reversing is already tried. The fact
    00144        * that function failed can have to do with a
    00145        * missing road bit, or inability to connect the
    00146        * different bits due to slopes. */
    00147       if (IsRoadTT() && !IsTram() && TryReverse()) return true;
    00148       m_err = EC_NO_WAY;
    00149       return false;
    00150     }
    00151     if (!Allow90degTurns()) {
    00152       m_new_td_bits &= (TrackdirBits)~(int)TrackdirCrossesTrackdirs(m_old_td);
    00153       if (m_new_td_bits == TRACKDIR_BIT_NONE) {
    00154         m_err = EC_90DEG;
    00155         return false;
    00156       }
    00157     }
    00158     return true;
    00159   }
    00160
    00161   inline bool MaskReservedTracks()
    00162   {
    00163     if (!DoTrackMasking()) return true;
    00164
    00165     if (m_is_station) {
    00166       /* Check skipped station tiles as well. */
    00167       TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
    00168       for (TileIndex tile = m_new_tile - diff * m_tiles_skipped; tile != m_new_tile; tile += diff) {
    00169         if (HasStationReservation(tile)) {
    00170           m_new_td_bits = TRACKDIR_BIT_NONE;
    00171           m_err = EC_RESERVED;
    00172           return false;
    00173         }
    00174       }
    00175     }
    00176
    00177     TrackBits reserved = GetReservedTrackbits(m_new_tile);
    00178     /* Mask already reserved trackdirs. */
    00179     m_new_td_bits &= ~TrackBitsToTrackdirBits(reserved);
    00180     /* Mask out all trackdirs that conflict with the reservation. */
    00181     Track t;
    00182     FOR_EACH_SET_TRACK(t, TrackdirBitsToTrackBits(m_new_td_bits)) {
    00183       if (TracksOverlap(reserved | TrackToTrackBits(t))) m_new_td_bits &= ~TrackToTrackdirBits(t);
    00184     }
    00185     if (m_new_td_bits == TRACKDIR_BIT_NONE) {
    00186       m_err = EC_RESERVED;
    00187       return false;
    00188     }
    00189     return true;
    00190   }
    00191
    00192 protected:
    00194   inline void FollowTileExit()
    00195   {
    00196     m_is_station = m_is_bridge = m_is_tunnel = false;
    00197     m_tiles_skipped = 0;
    00198
    00199     /* extra handling for tunnels and bridges in our direction */
    00200     if (IsTileType(m_old_tile, MP_TUNNELBRIDGE)) {
    00201       DiagDirection enterdir = GetTunnelBridgeDirection(m_old_tile);
    00202       if (enterdir == m_exitdir) {
    00203         /* we are entering the tunnel / bridge */
    00204         if (IsTunnel(m_old_tile)) {
    00205           m_is_tunnel = true;
    00206           m_new_tile = GetOtherTunnelEnd(m_old_tile);
    00207         } else { // IsBridge(m_old_tile)
    00208           m_is_bridge = true;
    00209           m_new_tile = GetOtherBridgeEnd(m_old_tile);
    00210         }
    00211         m_tiles_skipped = GetTunnelBridgeLength(m_new_tile, m_old_tile);
    00212         return;
    00213       }
    00214       assert(ReverseDiagDir(enterdir) == m_exitdir);
    00215     }
    00216
    00217     /* normal or station tile, do one step */
    00218     TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
    00219     m_new_tile = TILE_ADD(m_old_tile, diff);
    00220
    00221     /* special handling for stations */
    00222     if (IsRailTT() && HasStationTileRail(m_new_tile)) {
    00223       m_is_station = true;
    00224     } else if (IsRoadTT() && IsRoadStopTile(m_new_tile)) {
    00225       m_is_station = true;
    00226     } else {
    00227       m_is_station = false;
    00228     }
    00229   }
    00230
    00232   inline bool QueryNewTileTrackStatus()
    00233   {
    00234     CPerfStart perf(*m_pPerf);
    00235     if (IsRailTT() && IsPlainRailTile(m_new_tile)) {
    00236       m_new_td_bits = (TrackdirBits)(GetTrackBits(m_new_tile) * 0x101);
    00237     } else {
    00238       m_new_td_bits = TrackStatusToTrackdirBits(GetTileTrackStatus(m_new_tile, TT(), IsRoadTT() ? RoadVehicle::From(m_veh)->compatible_roadtypes : 0));
    00239
    00240       if (IsTram() && m_new_td_bits == 0) {
    00241         /* GetTileTrackStatus() returns 0 for single tram bits.
    00242          * As we cannot change it there (easily) without breaking something, change it here */
    00243         switch (GetSingleTramBit(m_new_tile)) {
    00244           case DIAGDIR_NE:
    00245           case DIAGDIR_SW:
    00246             m_new_td_bits = TRACKDIR_BIT_X_NE | TRACKDIR_BIT_X_SW;
    00247             break;
    00248
    00249           case DIAGDIR_NW:
    00250           case DIAGDIR_SE:
    00251             m_new_td_bits = TRACKDIR_BIT_Y_NW | TRACKDIR_BIT_Y_SE;
    00252             break;
    00253
    00254           default: break;
    00255         }
    00256       }
    00257     }
    00258     return (m_new_td_bits != TRACKDIR_BIT_NONE);
    00259   }
    00260
    00262   inline bool CanExitOldTile()
    00263   {
    00264     /* road stop can be left at one direction only unless it's a drive-through stop */
    00265     if (IsRoadTT() && IsStandardRoadStopTile(m_old_tile)) {
    00266       DiagDirection exitdir = GetRoadStopDir(m_old_tile);
    00267       if (exitdir != m_exitdir) {
    00268         m_err = EC_NO_WAY;
    00269         return false;
    00270       }
    00271     }
    00272
    00273     /* single tram bits can only be left in one direction */
    00274     if (IsTram()) {
    00275       DiagDirection single_tram = GetSingleTramBit(m_old_tile);
    00276       if (single_tram != INVALID_DIAGDIR && single_tram != m_exitdir) {
    00277         m_err = EC_NO_WAY;
    00278         return false;
    00279       }
    00280     }
    00281
    00282     /* road depots can be also left in one direction only */
    00283     if (IsRoadTT() && IsDepotTypeTile(m_old_tile, TT())) {
    00284       DiagDirection exitdir = GetRoadDepotDirection(m_old_tile);
    00285       if (exitdir != m_exitdir) {
    00286         m_err = EC_NO_WAY;
    00287         return false;
    00288       }
    00289     }
    00290     return true;
    00291   }
    00292
    00294   inline bool CanEnterNewTile()
    00295   {
    00296     if (IsRoadTT() && IsStandardRoadStopTile(m_new_tile)) {
    00297       /* road stop can be entered from one direction only unless it's a drive-through stop */
    00298       DiagDirection exitdir = GetRoadStopDir(m_new_tile);
    00299       if (ReverseDiagDir(exitdir) != m_exitdir) {
    00300         m_err = EC_NO_WAY;
    00301         return false;
    00302       }
    00303     }
    00304
    00305     /* single tram bits can only be entered from one direction */
    00306     if (IsTram()) {
    00307       DiagDirection single_tram = GetSingleTramBit(m_new_tile);
    00308       if (single_tram != INVALID_DIAGDIR && single_tram != ReverseDiagDir(m_exitdir)) {
    00309         m_err = EC_NO_WAY;
    00310         return false;
    00311       }
    00312     }
    00313
    00314     /* road and rail depots can also be entered from one direction only */
    00315     if (IsRoadTT() && IsDepotTypeTile(m_new_tile, TT())) {
    00316       DiagDirection exitdir = GetRoadDepotDirection(m_new_tile);
    00317       if (ReverseDiagDir(exitdir) != m_exitdir) {
    00318         m_err = EC_NO_WAY;
    00319         return false;
    00320       }
    00321       /* don't try to enter other company's depots */
    00322       if (GetTileOwner(m_new_tile) != m_veh_owner) {
    00323         m_err = EC_OWNER;
    00324         return false;
    00325       }
    00326     }
    00327     if (IsRailTT() && IsDepotTypeTile(m_new_tile, TT())) {
    00328       DiagDirection exitdir = GetRailDepotDirection(m_new_tile);
    00329       if (ReverseDiagDir(exitdir) != m_exitdir) {
    00330         m_err = EC_NO_WAY;
    00331         return false;
    00332       }
    00333     }
    00334
    00335     /* rail transport is possible only on tiles with the same owner as vehicle */
    00336     if (IsRailTT() && GetTileOwner(m_new_tile) != m_veh_owner) {
    00337       /* different owner */
    00338       m_err = EC_NO_WAY;
    00339       return false;
    00340     }
    00341
    00342     /* rail transport is possible only on compatible rail types */
    00343     if (IsRailTT()) {
    00344       RailType rail_type = GetTileRailType(m_new_tile);
    00345       if (!HasBit(m_railtypes, rail_type)) {
    00346         /* incompatible rail type */
    00347         m_err = EC_RAIL_TYPE;
    00348         return false;
    00349       }
    00350     }
    00351
    00352     /* tunnel holes and bridge ramps can be entered only from proper direction */
    00353     if (IsTileType(m_new_tile, MP_TUNNELBRIDGE)) {
    00354       if (IsTunnel(m_new_tile)) {
    00355         if (!m_is_tunnel) {
    00356           DiagDirection tunnel_enterdir = GetTunnelBridgeDirection(m_new_tile);
    00357           if (tunnel_enterdir != m_exitdir) {
    00358             m_err = EC_NO_WAY;
    00359             return false;
    00360           }
    00361         }
    00362       } else { // IsBridge(m_new_tile)
    00363         if (!m_is_bridge) {
    00364           DiagDirection ramp_enderdir = GetTunnelBridgeDirection(m_new_tile);
    00365           if (ramp_enderdir != m_exitdir) {
    00366             m_err = EC_NO_WAY;
    00367             return false;
    00368           }
    00369         }
    00370       }
    00371     }
    00372
    00373     /* special handling for rail stations - get to the end of platform */
    00374     if (IsRailTT() && m_is_station) {
    00375       /* entered railway station
    00376        * get platform length */
    00377       uint length = BaseStation::GetByTile(m_new_tile)->GetPlatformLength(m_new_tile, TrackdirToExitdir(m_old_td));
    00378       /* how big step we must do to get to the last platform tile; */
    00379       m_tiles_skipped = length - 1;
    00380       /* move to the platform end */
    00381       TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
    00382       diff *= m_tiles_skipped;
    00383       m_new_tile = TILE_ADD(m_new_tile, diff);
    00384       return true;
    00385     }
    00386
    00387     return true;
    00388   }
    00389
    00391   inline bool ForcedReverse()
    00392   {
    00393     /* rail and road depots cause reversing */
    00394     if (!IsWaterTT() && IsDepotTypeTile(m_old_tile, TT())) {
    00395       DiagDirection exitdir = IsRailTT() ? GetRailDepotDirection(m_old_tile) : GetRoadDepotDirection(m_old_tile);
    00396       if (exitdir != m_exitdir) {
    00397         /* reverse */
    00398         m_new_tile = m_old_tile;
    00399         m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
    00400         m_exitdir = exitdir;
    00401         m_tiles_skipped = 0;
    00402         m_is_tunnel = m_is_bridge = m_is_station = false;
    00403         return true;
    00404       }
    00405     }
    00406
    00407     /* single tram bits cause reversing */
    00408     if (IsTram() && GetSingleTramBit(m_old_tile) == ReverseDiagDir(m_exitdir)) {
    00409       /* reverse */
    00410       m_new_tile = m_old_tile;
    00411       m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
    00412       m_exitdir = ReverseDiagDir(m_exitdir);
    00413       m_tiles_skipped = 0;
    00414       m_is_tunnel = m_is_bridge = m_is_station = false;
    00415       return true;
    00416     }
    00417
    00418     return false;
    00419   }
    00420
    00422   inline bool TryReverse()
    00423   {
    00424     if (IsRoadTT() && !IsTram()) {
    00425       /* if we reached the end of road, we can reverse the RV and continue moving */
    00426       m_exitdir = ReverseDiagDir(m_exitdir);
    00427       /* new tile will be the same as old one */
    00428       m_new_tile = m_old_tile;
    00429       /* set new trackdir bits to all reachable trackdirs */
    00430       QueryNewTileTrackStatus();
    00431       m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
    00432       if (m_new_td_bits != TRACKDIR_BIT_NONE) {
    00433         /* we have some trackdirs reachable after reversal */
    00434         return true;
    00435       }
    00436     }
    00437     m_err = EC_NO_WAY;
    00438     return false;
    00439   }
    00440
    00441 public:
    00443   int GetSpeedLimit(int *pmin_speed = NULL) const
    00444   {
    00445     int min_speed = 0;
    00446     int max_speed = INT_MAX; // no limit
    00447
    00448     /* Check for on-bridge speed limit */
    00449     if (!IsWaterTT() && IsBridgeTile(m_old_tile)) {
    00450       int spd = GetBridgeSpec(GetBridgeType(m_old_tile))->speed;
    00451       if (IsRoadTT()) spd *= 2;
    00452       if (max_speed > spd) max_speed = spd;
    00453     }
    00454     /* Check for speed limit imposed by railtype */
    00455     if (IsRailTT()) {
    00456       uint16 rail_speed = GetRailTypeInfo(GetRailType(m_old_tile))->max_speed;
    00457       if (rail_speed > 0) max_speed = min(max_speed, rail_speed);
    00458     }
    00459
    00460     /* if min speed was requested, return it */
    00461     if (pmin_speed != NULL) *pmin_speed = min_speed;
    00462     return max_speed;
    00463   }
    00464 };
    00465
    00466 typedef CFollowTrackT<TRANSPORT_WATER, Ship,        true > CFollowTrackWater;
    00467 typedef CFollowTrackT<TRANSPORT_ROAD,  RoadVehicle, true > CFollowTrackRoad;
    00468 typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       true > CFollowTrackRail;
    00469
    00470 typedef CFollowTrackT<TRANSPORT_WATER, Ship,        false> CFollowTrackWaterNo90;
    00471 typedef CFollowTrackT<TRANSPORT_ROAD,  RoadVehicle, false> CFollowTrackRoadNo90;
    00472 typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       false> CFollowTrackRailNo90;
    00473
    00474 typedef CFollowTrackT<TRANSPORT_RAIL, Train, true,  true > CFollowTrackFreeRail;
    00475 typedef CFollowTrackT<TRANSPORT_RAIL, Train, false, true > CFollowTrackFreeRailNo90;
    00476
    00477 #endif /* FOLLOW_TRACK_HPP */