# follow_track.hpp

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    00001 /* $Id: follow_track.hpp 19312 2010-03-03 23:24:37Z 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
    00027 template <TransportType Ttr_type_, typename VehicleType, bool T90deg_turns_allowed_ = true, bool Tmask_reserved_tracks = false>
    00028 struct CFollowTrackT
    00029 {
    00030   enum ErrorCode {
    00031     EC_NONE,
    00032     EC_OWNER,
    00033     EC_RAIL_TYPE,
    00034     EC_90DEG,
    00035     EC_NO_WAY,
    00036     EC_RESERVED,
    00037   };
    00038
    00039   const VehicleType  *m_veh;
    00040   Owner               m_veh_owner;
    00041   TileIndex           m_old_tile;
    00042   Trackdir            m_old_td;
    00043   TileIndex           m_new_tile;
    00044   TrackdirBits        m_new_td_bits;
    00045   DiagDirection       m_exitdir;
    00046   bool                m_is_tunnel;
    00047   bool                m_is_bridge;
    00048   bool                m_is_station;
    00049   int                 m_tiles_skipped;
    00050   ErrorCode           m_err;
    00051   CPerformanceTimer  *m_pPerf;
    00052   RailTypes           m_railtypes;
    00053
    00054   FORCEINLINE CFollowTrackT(const VehicleType *v = NULL, RailTypes railtype_override = INVALID_RAILTYPES, CPerformanceTimer *pPerf = NULL)
    00055   {
    00056     Init(v, railtype_override, pPerf);
    00057   }
    00058
    00059   FORCEINLINE CFollowTrackT(Owner o, RailTypes railtype_override = INVALID_RAILTYPES, CPerformanceTimer *pPerf = NULL)
    00060   {
    00061     m_veh = NULL;
    00062     Init(o, railtype_override, pPerf);
    00063   }
    00064
    00065   FORCEINLINE void Init(const VehicleType *v, RailTypes railtype_override, CPerformanceTimer *pPerf)
    00066   {
    00067     assert(!IsRailTT() || (v != NULL && v->type == VEH_TRAIN));
    00068     m_veh = v;
    00069     Init(v != NULL ? v->owner : INVALID_OWNER, IsRailTT() && railtype_override == INVALID_RAILTYPES ? Train::From(v)->compatible_railtypes : railtype_override, pPerf);
    00070   }
    00071
    00072   FORCEINLINE void Init(Owner o, RailTypes railtype_override, CPerformanceTimer *pPerf)
    00073   {
    00074     assert((!IsRoadTT() || m_veh != NULL) && (!IsRailTT() || railtype_override != INVALID_RAILTYPES));
    00075     m_veh_owner = o;
    00076     m_pPerf = pPerf;
    00077     /* don't worry, all is inlined so compiler should remove unnecessary initializations */
    00078     m_new_tile = INVALID_TILE;
    00079     m_new_td_bits = TRACKDIR_BIT_NONE;
    00080     m_exitdir = INVALID_DIAGDIR;
    00081     m_is_station = m_is_bridge = m_is_tunnel = false;
    00082     m_tiles_skipped = 0;
    00083     m_err = EC_NONE;
    00084     m_railtypes = railtype_override;
    00085   }
    00086
    00087   FORCEINLINE static TransportType TT() {return Ttr_type_;}
    00088   FORCEINLINE static bool IsWaterTT() {return TT() == TRANSPORT_WATER;}
    00089   FORCEINLINE static bool IsRailTT() {return TT() == TRANSPORT_RAIL;}
    00090   FORCEINLINE bool IsTram() {return IsRoadTT() && HasBit(RoadVehicle::From(m_veh)->compatible_roadtypes, ROADTYPE_TRAM);}
    00091   FORCEINLINE static bool IsRoadTT() {return TT() == TRANSPORT_ROAD;}
    00092   FORCEINLINE static bool Allow90degTurns() {return T90deg_turns_allowed_;}
    00093   FORCEINLINE static bool DoTrackMasking() {return IsRailTT() && Tmask_reserved_tracks;}
    00094
    00096   FORCEINLINE DiagDirection GetSingleTramBit(TileIndex tile)
    00097   {
    00098     assert(IsTram()); // this function shouldn't be called in other cases
    00099
    00100     if (IsNormalRoadTile(tile)) {
    00101       RoadBits rb = GetRoadBits(tile, ROADTYPE_TRAM);
    00102       switch (rb) {
    00103         case ROAD_NW: return DIAGDIR_NW;
    00104         case ROAD_SW: return DIAGDIR_SW;
    00105         case ROAD_SE: return DIAGDIR_SE;
    00106         case ROAD_NE: return DIAGDIR_NE;
    00107         default: break;
    00108       }
    00109     }
    00110     return INVALID_DIAGDIR;
    00111   }
    00112
    00115   inline bool Follow(TileIndex old_tile, Trackdir old_td)
    00116   {
    00117     m_old_tile = old_tile;
    00118     m_old_td = old_td;
    00119     m_err = EC_NONE;
    00120     assert(((TrackStatusToTrackdirBits(GetTileTrackStatus(m_old_tile, TT(), IsRoadTT() && m_veh != NULL ? RoadVehicle::From(m_veh)->compatible_roadtypes : 0)) & TrackdirToTrackdirBits(m_old_td)) != 0) ||
    00121            (IsTram() && GetSingleTramBit(m_old_tile) != INVALID_DIAGDIR)); // Disable the assertion for single tram bits
    00122     m_exitdir = TrackdirToExitdir(m_old_td);
    00123     if (ForcedReverse()) return true;
    00124     if (!CanExitOldTile()) return false;
    00125     FollowTileExit();
    00126     if (!QueryNewTileTrackStatus()) return TryReverse();
    00127     if (!CanEnterNewTile()) return false;
    00128     m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
    00129     if (m_new_td_bits == TRACKDIR_BIT_NONE) {
    00130       m_err = EC_NO_WAY;
    00131       return false;
    00132     }
    00133     if (!Allow90degTurns()) {
    00134       m_new_td_bits &= (TrackdirBits)~(int)TrackdirCrossesTrackdirs(m_old_td);
    00135       if (m_new_td_bits == TRACKDIR_BIT_NONE) {
    00136         m_err = EC_90DEG;
    00137         return false;
    00138       }
    00139     }
    00140     return true;
    00141   }
    00142
    00143   inline bool MaskReservedTracks()
    00144   {
    00145     if (!DoTrackMasking()) return true;
    00146
    00147     if (m_is_station) {
    00148       /* Check skipped station tiles as well. */
    00149       TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
    00150       for (TileIndex tile = m_new_tile - diff * m_tiles_skipped; tile != m_new_tile; tile += diff) {
    00151         if (HasStationReservation(tile)) {
    00152           m_new_td_bits = TRACKDIR_BIT_NONE;
    00153           m_err = EC_RESERVED;
    00154           return false;
    00155         }
    00156       }
    00157     }
    00158
    00159     TrackBits reserved = GetReservedTrackbits(m_new_tile);
    00160     /* Mask already reserved trackdirs. */
    00161     m_new_td_bits &= ~TrackBitsToTrackdirBits(reserved);
    00162     /* Mask out all trackdirs that conflict with the reservation. */
    00163     uint bits = (uint)TrackdirBitsToTrackBits(m_new_td_bits);
    00164     int i;
    00165     FOR_EACH_SET_BIT(i, bits) {
    00166       if (TracksOverlap(reserved | TrackToTrackBits((Track)i))) m_new_td_bits &= ~TrackToTrackdirBits((Track)i);
    00167     }
    00168     if (m_new_td_bits == TRACKDIR_BIT_NONE) {
    00169       m_err = EC_RESERVED;
    00170       return false;
    00171     }
    00172     return true;
    00173   }
    00174
    00175 protected:
    00177   FORCEINLINE void FollowTileExit()
    00178   {
    00179     m_is_station = m_is_bridge = m_is_tunnel = false;
    00180     m_tiles_skipped = 0;
    00181
    00182     /* extra handling for tunnels and bridges in our direction */
    00183     if (IsTileType(m_old_tile, MP_TUNNELBRIDGE)) {
    00184       DiagDirection enterdir = GetTunnelBridgeDirection(m_old_tile);
    00185       if (enterdir == m_exitdir) {
    00186         /* we are entering the tunnel / bridge */
    00187         if (IsTunnel(m_old_tile)) {
    00188           m_is_tunnel = true;
    00189           m_new_tile = GetOtherTunnelEnd(m_old_tile);
    00190         } else { // IsBridge(m_old_tile)
    00191           m_is_bridge = true;
    00192           m_new_tile = GetOtherBridgeEnd(m_old_tile);
    00193         }
    00194         m_tiles_skipped = GetTunnelBridgeLength(m_new_tile, m_old_tile);
    00195         return;
    00196       }
    00197       assert(ReverseDiagDir(enterdir) == m_exitdir);
    00198     }
    00199
    00200     /* normal or station tile, do one step */
    00201     TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
    00202     m_new_tile = TILE_ADD(m_old_tile, diff);
    00203
    00204     /* special handling for stations */
    00205     if (IsRailTT() && HasStationTileRail(m_new_tile)) {
    00206       m_is_station = true;
    00207     } else if (IsRoadTT() && IsRoadStopTile(m_new_tile)) {
    00208       m_is_station = true;
    00209     } else {
    00210       m_is_station = false;
    00211     }
    00212   }
    00213
    00215   FORCEINLINE bool QueryNewTileTrackStatus()
    00216   {
    00217     CPerfStart perf(*m_pPerf);
    00218     if (IsRailTT() && IsPlainRailTile(m_new_tile)) {
    00219       m_new_td_bits = (TrackdirBits)(GetTrackBits(m_new_tile) * 0x101);
    00220     } else {
    00221       m_new_td_bits = TrackStatusToTrackdirBits(GetTileTrackStatus(m_new_tile, TT(), IsRoadTT() && m_veh != NULL ? RoadVehicle::From(m_veh)->compatible_roadtypes : 0));
    00222
    00223       if (IsTram() && m_new_td_bits == 0) {
    00224         /* GetTileTrackStatus() returns 0 for single tram bits.
    00225          * As we cannot change it there (easily) without breaking something, change it here */
    00226         switch (GetSingleTramBit(m_new_tile)) {
    00227           case DIAGDIR_NE:
    00228           case DIAGDIR_SW:
    00229             m_new_td_bits = TRACKDIR_BIT_X_NE | TRACKDIR_BIT_X_SW;
    00230             break;
    00231
    00232           case DIAGDIR_NW:
    00233           case DIAGDIR_SE:
    00234             m_new_td_bits = TRACKDIR_BIT_Y_NW | TRACKDIR_BIT_Y_SE;
    00235             break;
    00236
    00237           default: break;
    00238         }
    00239       }
    00240     }
    00241     return (m_new_td_bits != TRACKDIR_BIT_NONE);
    00242   }
    00243
    00245   FORCEINLINE bool CanExitOldTile()
    00246   {
    00247     /* road stop can be left at one direction only unless it's a drive-through stop */
    00248     if (IsRoadTT() && IsStandardRoadStopTile(m_old_tile)) {
    00249       DiagDirection exitdir = GetRoadStopDir(m_old_tile);
    00250       if (exitdir != m_exitdir) {
    00251         m_err = EC_NO_WAY;
    00252         return false;
    00253       }
    00254     }
    00255
    00256     /* single tram bits can only be left in one direction */
    00257     if (IsTram()) {
    00258       DiagDirection single_tram = GetSingleTramBit(m_old_tile);
    00259       if (single_tram != INVALID_DIAGDIR && single_tram != m_exitdir) {
    00260         m_err = EC_NO_WAY;
    00261         return false;
    00262       }
    00263     }
    00264
    00265     /* road depots can be also left in one direction only */
    00266     if (IsRoadTT() && IsDepotTypeTile(m_old_tile, TT())) {
    00267       DiagDirection exitdir = GetRoadDepotDirection(m_old_tile);
    00268       if (exitdir != m_exitdir) {
    00269         m_err = EC_NO_WAY;
    00270         return false;
    00271       }
    00272     }
    00273     return true;
    00274   }
    00275
    00277   FORCEINLINE bool CanEnterNewTile()
    00278   {
    00279     if (IsRoadTT() && IsStandardRoadStopTile(m_new_tile)) {
    00280       /* road stop can be entered from one direction only unless it's a drive-through stop */
    00281       DiagDirection exitdir = GetRoadStopDir(m_new_tile);
    00282       if (ReverseDiagDir(exitdir) != m_exitdir) {
    00283         m_err = EC_NO_WAY;
    00284         return false;
    00285       }
    00286     }
    00287
    00288     /* single tram bits can only be entered from one direction */
    00289     if (IsTram()) {
    00290       DiagDirection single_tram = GetSingleTramBit(m_new_tile);
    00291       if (single_tram != INVALID_DIAGDIR && single_tram != ReverseDiagDir(m_exitdir)) {
    00292         m_err = EC_NO_WAY;
    00293         return false;
    00294       }
    00295     }
    00296
    00297     /* road and rail depots can also be entered from one direction only */
    00298     if (IsRoadTT() && IsDepotTypeTile(m_new_tile, TT())) {
    00299       DiagDirection exitdir = GetRoadDepotDirection(m_new_tile);
    00300       if (ReverseDiagDir(exitdir) != m_exitdir) {
    00301         m_err = EC_NO_WAY;
    00302         return false;
    00303       }
    00304       /* don't try to enter other company's depots */
    00305       if (GetTileOwner(m_new_tile) != m_veh_owner) {
    00306         m_err = EC_OWNER;
    00307         return false;
    00308       }
    00309     }
    00310     if (IsRailTT() && IsDepotTypeTile(m_new_tile, TT())) {
    00311       DiagDirection exitdir = GetRailDepotDirection(m_new_tile);
    00312       if (ReverseDiagDir(exitdir) != m_exitdir) {
    00313         m_err = EC_NO_WAY;
    00314         return false;
    00315       }
    00316     }
    00317
    00318     /* rail transport is possible only on tiles with the same owner as vehicle */
    00319     if (IsRailTT() && GetTileOwner(m_new_tile) != m_veh_owner) {
    00320       /* different owner */
    00321       m_err = EC_NO_WAY;
    00322       return false;
    00323     }
    00324
    00325     /* rail transport is possible only on compatible rail types */
    00326     if (IsRailTT()) {
    00327       RailType rail_type = GetTileRailType(m_new_tile);
    00328       if (!HasBit(m_railtypes, rail_type)) {
    00329         /* incompatible rail type */
    00330         m_err = EC_RAIL_TYPE;
    00331         return false;
    00332       }
    00333     }
    00334
    00335     /* tunnel holes and bridge ramps can be entered only from proper direction */
    00336     if (IsTileType(m_new_tile, MP_TUNNELBRIDGE)) {
    00337       if (IsTunnel(m_new_tile)) {
    00338         if (!m_is_tunnel) {
    00339           DiagDirection tunnel_enterdir = GetTunnelBridgeDirection(m_new_tile);
    00340           if (tunnel_enterdir != m_exitdir) {
    00341             m_err = EC_NO_WAY;
    00342             return false;
    00343           }
    00344         }
    00345       } else { // IsBridge(m_new_tile)
    00346         if (!m_is_bridge) {
    00347           DiagDirection ramp_enderdir = GetTunnelBridgeDirection(m_new_tile);
    00348           if (ramp_enderdir != m_exitdir) {
    00349             m_err = EC_NO_WAY;
    00350             return false;
    00351           }
    00352         }
    00353       }
    00354     }
    00355
    00356     /* special handling for rail stations - get to the end of platform */
    00357     if (IsRailTT() && m_is_station) {
    00358       /* entered railway station
    00359        * get platform length */
    00360       uint length = BaseStation::GetByTile(m_new_tile)->GetPlatformLength(m_new_tile, TrackdirToExitdir(m_old_td));
    00361       /* how big step we must do to get to the last platform tile; */
    00362       m_tiles_skipped = length - 1;
    00363       /* move to the platform end */
    00364       TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
    00365       diff *= m_tiles_skipped;
    00366       m_new_tile = TILE_ADD(m_new_tile, diff);
    00367       return true;
    00368     }
    00369
    00370     return true;
    00371   }
    00372
    00374   FORCEINLINE bool ForcedReverse()
    00375   {
    00376     /* rail and road depots cause reversing */
    00377     if (!IsWaterTT() && IsDepotTypeTile(m_old_tile, TT())) {
    00378       DiagDirection exitdir = IsRailTT() ? GetRailDepotDirection(m_old_tile) : GetRoadDepotDirection(m_old_tile);
    00379       if (exitdir != m_exitdir) {
    00380         /* reverse */
    00381         m_new_tile = m_old_tile;
    00382         m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
    00383         m_exitdir = exitdir;
    00384         m_tiles_skipped = 0;
    00385         m_is_tunnel = m_is_bridge = m_is_station = false;
    00386         return true;
    00387       }
    00388     }
    00389
    00390     /* single tram bits cause reversing */
    00391     if (IsTram() && GetSingleTramBit(m_old_tile) == ReverseDiagDir(m_exitdir)) {
    00392       /* reverse */
    00393       m_new_tile = m_old_tile;
    00394       m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
    00395       m_exitdir = ReverseDiagDir(m_exitdir);
    00396       m_tiles_skipped = 0;
    00397       m_is_tunnel = m_is_bridge = m_is_station = false;
    00398       return true;
    00399     }
    00400
    00401     return false;
    00402   }
    00403
    00405   FORCEINLINE bool TryReverse()
    00406   {
    00407     if (IsRoadTT() && !IsTram()) {
    00408       /* if we reached the end of road, we can reverse the RV and continue moving */
    00409       m_exitdir = ReverseDiagDir(m_exitdir);
    00410       /* new tile will be the same as old one */
    00411       m_new_tile = m_old_tile;
    00412       /* set new trackdir bits to all reachable trackdirs */
    00413       QueryNewTileTrackStatus();
    00414       m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
    00415       if (m_new_td_bits != TRACKDIR_BIT_NONE) {
    00416         /* we have some trackdirs reachable after reversal */
    00417         return true;
    00418       }
    00419     }
    00420     m_err = EC_NO_WAY;
    00421     return false;
    00422   }
    00423
    00424 public:
    00426   int GetSpeedLimit(int *pmin_speed = NULL) const
    00427   {
    00428     int min_speed = 0;
    00429     int max_speed = INT_MAX; // no limit
    00430
    00431     /* Check for on-bridge speed limit */
    00432     if (!IsWaterTT() && IsBridgeTile(m_old_tile)) {
    00433       int spd = GetBridgeSpec(GetBridgeType(m_old_tile))->speed;
    00434       if (IsRoadTT()) spd *= 2;
    00435       if (max_speed > spd) max_speed = spd;
    00436     }
    00437     /* Check for speed limit imposed by railtype */
    00438     if (IsRailTT()) {
    00439       uint16 rail_speed = GetRailTypeInfo(GetRailType(m_old_tile))->max_speed;
    00440       if (rail_speed > 0) max_speed = min(max_speed, rail_speed);
    00441     }
    00442
    00443     /* if min speed was requested, return it */
    00444     if (pmin_speed) *pmin_speed = min_speed;
    00445     return max_speed;
    00446   }
    00447 };
    00448
    00449 typedef CFollowTrackT<TRANSPORT_WATER, Ship,        true > CFollowTrackWater;
    00450 typedef CFollowTrackT<TRANSPORT_ROAD,  RoadVehicle, true > CFollowTrackRoad;
    00451 typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       true > CFollowTrackRail;
    00452
    00453 typedef CFollowTrackT<TRANSPORT_WATER, Ship,        false> CFollowTrackWaterNo90;
    00454 typedef CFollowTrackT<TRANSPORT_ROAD,  RoadVehicle, false> CFollowTrackRoadNo90;
    00455 typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       false> CFollowTrackRailNo90;
    00456
    00457 typedef CFollowTrackT<TRANSPORT_RAIL, Train, true,  true > CFollowTrackFreeRail;
    00458 typedef CFollowTrackT<TRANSPORT_RAIL, Train, false, true > CFollowTrackFreeRailNo90;
    00459
    00460 #endif /* FOLLOW_TRACK_HPP */