follow_track.hpp

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00001 /* $Id$ */
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 "../depot_map.h"
00016 #include "../pbs.h"
00017 #include "../roadveh.h"
00018 #include "../station_base.h"
00019 #include "../train.h"
00020 #include "../tunnelbridge.h"
00021 #include "../tunnelbridge_map.h"
00022 #include "../infrastructure_func.h"
00023 #include "pf_performance_timer.hpp"
00024 
00028 template <TransportType Ttr_type_, typename VehicleType, bool T90deg_turns_allowed_ = true, bool Tmask_reserved_tracks = false>
00029 struct CFollowTrackT
00030 {
00031   enum ErrorCode {
00032     EC_NONE,
00033     EC_OWNER,
00034     EC_RAIL_TYPE,
00035     EC_90DEG,
00036     EC_NO_WAY,
00037     EC_RESERVED,
00038   };
00039 
00040   const VehicleType  *m_veh;           
00041   Owner               m_veh_owner;     
00042   TileIndex           m_old_tile;      
00043   Trackdir            m_old_td;        
00044   TileIndex           m_new_tile;      
00045   TrackdirBits        m_new_td_bits;   
00046   DiagDirection       m_exitdir;       
00047   bool                m_is_tunnel;     
00048   bool                m_is_bridge;     
00049   bool                m_is_station;    
00050   int                 m_tiles_skipped; 
00051   ErrorCode           m_err;
00052   CPerformanceTimer  *m_pPerf;
00053   RailTypes           m_railtypes;
00054 
00055   FORCEINLINE CFollowTrackT(const VehicleType *v = NULL, RailTypes railtype_override = INVALID_RAILTYPES, CPerformanceTimer *pPerf = NULL)
00056   {
00057     Init(v, railtype_override, pPerf);
00058   }
00059 
00060   FORCEINLINE CFollowTrackT(Owner o, RailTypes railtype_override = INVALID_RAILTYPES, CPerformanceTimer *pPerf = NULL)
00061   {
00062     m_veh = NULL;
00063     Init(o, railtype_override, pPerf);
00064   }
00065 
00066   FORCEINLINE void Init(const VehicleType *v, RailTypes railtype_override, CPerformanceTimer *pPerf)
00067   {
00068     assert(!IsRailTT() || (v != NULL && v->type == VEH_TRAIN));
00069     m_veh = v;
00070     Init(v != NULL ? v->owner : INVALID_OWNER, IsRailTT() && railtype_override == INVALID_RAILTYPES ? Train::From(v)->compatible_railtypes : railtype_override, pPerf);
00071   }
00072 
00073   FORCEINLINE void Init(Owner o, RailTypes railtype_override, CPerformanceTimer *pPerf)
00074   {
00075     assert((!IsRoadTT() || m_veh != NULL) && (!IsRailTT() || railtype_override != INVALID_RAILTYPES));
00076     m_veh_owner = o;
00077     m_pPerf = pPerf;
00078     /* don't worry, all is inlined so compiler should remove unnecessary initializations */
00079     m_new_tile = INVALID_TILE;
00080     m_new_td_bits = TRACKDIR_BIT_NONE;
00081     m_exitdir = INVALID_DIAGDIR;
00082     m_is_station = m_is_bridge = m_is_tunnel = false;
00083     m_tiles_skipped = 0;
00084     m_err = EC_NONE;
00085     m_railtypes = railtype_override;
00086   }
00087 
00088   FORCEINLINE static TransportType TT() {return Ttr_type_;}
00089   FORCEINLINE static bool IsWaterTT() {return TT() == TRANSPORT_WATER;}
00090   FORCEINLINE static bool IsRailTT() {return TT() == TRANSPORT_RAIL;}
00091   FORCEINLINE bool IsTram() {return IsRoadTT() && HasBit(RoadVehicle::From(m_veh)->compatible_roadtypes, ROADTYPE_TRAM);}
00092   FORCEINLINE static bool IsRoadTT() {return TT() == TRANSPORT_ROAD;}
00093   FORCEINLINE static bool Allow90degTurns() {return T90deg_turns_allowed_;}
00094   FORCEINLINE static bool DoTrackMasking() {return IsRailTT() && Tmask_reserved_tracks;}
00095 
00097   FORCEINLINE DiagDirection GetSingleTramBit(TileIndex tile)
00098   {
00099     assert(IsTram()); // this function shouldn't be called in other cases
00100 
00101     if (IsNormalRoadTile(tile)) {
00102       RoadBits rb = GetRoadBits(tile, ROADTYPE_TRAM);
00103       switch (rb) {
00104         case ROAD_NW: return DIAGDIR_NW;
00105         case ROAD_SW: return DIAGDIR_SW;
00106         case ROAD_SE: return DIAGDIR_SE;
00107         case ROAD_NE: return DIAGDIR_NE;
00108         default: break;
00109       }
00110     }
00111     return INVALID_DIAGDIR;
00112   }
00113 
00116   inline bool Follow(TileIndex old_tile, Trackdir old_td)
00117   {
00118     m_old_tile = old_tile;
00119     m_old_td = old_td;
00120     m_err = EC_NONE;
00121     assert(((TrackStatusToTrackdirBits(GetTileTrackStatus(m_old_tile, TT(), IsRoadTT() && m_veh != NULL ? RoadVehicle::From(m_veh)->compatible_roadtypes : 0)) & TrackdirToTrackdirBits(m_old_td)) != 0) ||
00122            (IsTram() && GetSingleTramBit(m_old_tile) != INVALID_DIAGDIR)); // Disable the assertion for single tram bits
00123     m_exitdir = TrackdirToExitdir(m_old_td);
00124     if (ForcedReverse()) return true;
00125     if (!CanExitOldTile()) return false;
00126     FollowTileExit();
00127     if (!QueryNewTileTrackStatus()) return TryReverse();
00128     if (!CanEnterNewTile()) return false;
00129     m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
00130     if (m_new_td_bits == TRACKDIR_BIT_NONE) {
00131       m_err = EC_NO_WAY;
00132       return false;
00133     }
00134     if (!Allow90degTurns()) {
00135       m_new_td_bits &= (TrackdirBits)~(int)TrackdirCrossesTrackdirs(m_old_td);
00136       if (m_new_td_bits == TRACKDIR_BIT_NONE) {
00137         m_err = EC_90DEG;
00138         return false;
00139       }
00140     }
00141     return true;
00142   }
00143 
00144   inline bool MaskReservedTracks()
00145   {
00146     if (!DoTrackMasking()) return true;
00147 
00148     if (m_is_station) {
00149       /* Check skipped station tiles as well. */
00150       TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
00151       for (TileIndex tile = m_new_tile - diff * m_tiles_skipped; tile != m_new_tile; tile += diff) {
00152         if (HasStationReservation(tile)) {
00153           m_new_td_bits = TRACKDIR_BIT_NONE;
00154           m_err = EC_RESERVED;
00155           return false;
00156         }
00157       }
00158     }
00159 
00160     TrackBits reserved = GetReservedTrackbits(m_new_tile);
00161     /* Mask already reserved trackdirs. */
00162     m_new_td_bits &= ~TrackBitsToTrackdirBits(reserved);
00163     /* Mask out all trackdirs that conflict with the reservation. */
00164     uint bits = (uint)TrackdirBitsToTrackBits(m_new_td_bits);
00165     int i;
00166     FOR_EACH_SET_BIT(i, bits) {
00167       if (TracksOverlap(reserved | TrackToTrackBits((Track)i))) m_new_td_bits &= ~TrackToTrackdirBits((Track)i);
00168     }
00169     if (m_new_td_bits == TRACKDIR_BIT_NONE) {
00170       m_err = EC_RESERVED;
00171       return false;
00172     }
00173     return true;
00174   }
00175 
00176 protected:
00178   FORCEINLINE void FollowTileExit()
00179   {
00180     m_is_station = m_is_bridge = m_is_tunnel = false;
00181     m_tiles_skipped = 0;
00182 
00183     /* extra handling for tunnels and bridges in our direction */
00184     if (IsTileType(m_old_tile, MP_TUNNELBRIDGE)) {
00185       DiagDirection enterdir = GetTunnelBridgeDirection(m_old_tile);
00186       if (enterdir == m_exitdir) {
00187         /* we are entering the tunnel / bridge */
00188         if (IsTunnel(m_old_tile)) {
00189           m_is_tunnel = true;
00190           m_new_tile = GetOtherTunnelEnd(m_old_tile);
00191         } else { // IsBridge(m_old_tile)
00192           m_is_bridge = true;
00193           m_new_tile = GetOtherBridgeEnd(m_old_tile);
00194         }
00195         m_tiles_skipped = GetTunnelBridgeLength(m_new_tile, m_old_tile);
00196         return;
00197       }
00198       assert(ReverseDiagDir(enterdir) == m_exitdir);
00199     }
00200 
00201     /* normal or station tile, do one step */
00202     TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
00203     m_new_tile = TILE_ADD(m_old_tile, diff);
00204 
00205     /* special handling for stations */
00206     if (IsRailTT() && HasStationTileRail(m_new_tile)) {
00207       m_is_station = true;
00208     } else if (IsRoadTT() && IsRoadStopTile(m_new_tile)) {
00209       m_is_station = true;
00210     } else {
00211       m_is_station = false;
00212     }
00213   }
00214 
00216   FORCEINLINE bool QueryNewTileTrackStatus()
00217   {
00218     CPerfStart perf(*m_pPerf);
00219     if (IsRailTT() && IsPlainRailTile(m_new_tile)) {
00220       m_new_td_bits = (TrackdirBits)(GetTrackBits(m_new_tile) * 0x101);
00221     } else {
00222       m_new_td_bits = TrackStatusToTrackdirBits(GetTileTrackStatus(m_new_tile, TT(), IsRoadTT() && m_veh != NULL ? RoadVehicle::From(m_veh)->compatible_roadtypes : 0));
00223 
00224       if (IsTram() && m_new_td_bits == 0) {
00225         /* GetTileTrackStatus() returns 0 for single tram bits.
00226          * As we cannot change it there (easily) without breaking something, change it here */
00227         switch (GetSingleTramBit(m_new_tile)) {
00228           case DIAGDIR_NE:
00229           case DIAGDIR_SW:
00230             m_new_td_bits = TRACKDIR_BIT_X_NE | TRACKDIR_BIT_X_SW;
00231             break;
00232 
00233           case DIAGDIR_NW:
00234           case DIAGDIR_SE:
00235             m_new_td_bits = TRACKDIR_BIT_Y_NW | TRACKDIR_BIT_Y_SE;
00236             break;
00237 
00238           default: break;
00239         }
00240       }
00241     }
00242     return (m_new_td_bits != TRACKDIR_BIT_NONE);
00243   }
00244 
00246   FORCEINLINE bool CanExitOldTile()
00247   {
00248     /* road stop can be left at one direction only unless it's a drive-through stop */
00249     if (IsRoadTT() && IsStandardRoadStopTile(m_old_tile)) {
00250       DiagDirection exitdir = GetRoadStopDir(m_old_tile);
00251       if (exitdir != m_exitdir) {
00252         m_err = EC_NO_WAY;
00253         return false;
00254       }
00255     }
00256 
00257     /* single tram bits can only be left in one direction */
00258     if (IsTram()) {
00259       DiagDirection single_tram = GetSingleTramBit(m_old_tile);
00260       if (single_tram != INVALID_DIAGDIR && single_tram != m_exitdir) {
00261         m_err = EC_NO_WAY;
00262         return false;
00263       }
00264     }
00265 
00266     /* road depots can be also left in one direction only */
00267     if (IsRoadTT() && IsDepotTypeTile(m_old_tile, TT())) {
00268       DiagDirection exitdir = GetRoadDepotDirection(m_old_tile);
00269       if (exitdir != m_exitdir) {
00270         m_err = EC_NO_WAY;
00271         return false;
00272       }
00273     }
00274     return true;
00275   }
00276 
00278   FORCEINLINE bool CanEnterNewTile()
00279   {
00280     if (IsRoadTT() && IsStandardRoadStopTile(m_new_tile)) {
00281       /* road stop can be entered from one direction only unless it's a drive-through stop */
00282       DiagDirection exitdir = GetRoadStopDir(m_new_tile);
00283       if (ReverseDiagDir(exitdir) != m_exitdir) {
00284         m_err = EC_NO_WAY;
00285         return false;
00286       }
00287       /* road stops shouldn't be entered unless allowed to */
00288       if (!IsInfraTileUsageAllowed(m_new_tile, m_veh_owner, VEH_ROAD)) {
00289         m_err = EC_OWNER;
00290         return false;
00291       }
00292     }
00293 
00294     /* single tram bits can only be entered from one direction */
00295     if (IsTram()) {
00296       DiagDirection single_tram = GetSingleTramBit(m_new_tile);
00297       if (single_tram != INVALID_DIAGDIR && single_tram != ReverseDiagDir(m_exitdir)) {
00298         m_err = EC_NO_WAY;
00299         return false;
00300       }
00301     }
00302 
00303     /* road and rail depots can also be entered from one direction only */
00304     if (IsRoadTT() && IsDepotTypeTile(m_new_tile, TT())) {
00305       DiagDirection exitdir = GetRoadDepotDirection(m_new_tile);
00306       if (ReverseDiagDir(exitdir) != m_exitdir) {
00307         m_err = EC_NO_WAY;
00308         return false;
00309       }
00310       /* don't try to enter other company's depots if not allowed */
00311       if (!IsInfraTileUsageAllowed(m_new_tile, m_veh_owner, VEH_ROAD)) {
00312         m_err = EC_OWNER;
00313         return false;
00314       }
00315     }
00316     if (IsRailTT() && IsDepotTypeTile(m_new_tile, TT())) {
00317       DiagDirection exitdir = GetRailDepotDirection(m_new_tile);
00318       if (ReverseDiagDir(exitdir) != m_exitdir) {
00319         m_err = EC_NO_WAY;
00320         return false;
00321       }
00322     }
00323 
00324     /* rail transport is possible only on tiles with the same owner as vehicle if sharing of tracks is disabled */
00325     if (IsRailTT() && !IsInfraTileUsageAllowed(m_new_tile, m_veh_owner, VEH_TRAIN)) {
00326       /* different owner */
00327       m_err = EC_NO_WAY;
00328       return false;
00329     }
00330 
00331     /* rail transport is possible only on compatible rail types */
00332     if (IsRailTT()) {
00333       RailType rail_type = GetTileRailType(m_new_tile);
00334       if (!HasBit(m_railtypes, rail_type)) {
00335         /* incompatible rail type */
00336         m_err = EC_RAIL_TYPE;
00337         return false;
00338       }
00339     }
00340 
00341     /* tunnel holes and bridge ramps can be entered only from proper direction */
00342     if (IsTileType(m_new_tile, MP_TUNNELBRIDGE)) {
00343       if (IsTunnel(m_new_tile)) {
00344         if (!m_is_tunnel) {
00345           DiagDirection tunnel_enterdir = GetTunnelBridgeDirection(m_new_tile);
00346           if (tunnel_enterdir != m_exitdir) {
00347             m_err = EC_NO_WAY;
00348             return false;
00349           }
00350         }
00351       } else { // IsBridge(m_new_tile)
00352         if (!m_is_bridge) {
00353           DiagDirection ramp_enderdir = GetTunnelBridgeDirection(m_new_tile);
00354           if (ramp_enderdir != m_exitdir) {
00355             m_err = EC_NO_WAY;
00356             return false;
00357           }
00358         }
00359       }
00360     }
00361 
00362     /* special handling for rail stations - get to the end of platform */
00363     if (IsRailTT() && m_is_station) {
00364       /* entered railway station
00365        * get platform length */
00366       uint length = BaseStation::GetByTile(m_new_tile)->GetPlatformLength(m_new_tile, TrackdirToExitdir(m_old_td));
00367       /* how big step we must do to get to the last platform tile; */
00368       m_tiles_skipped = length - 1;
00369       /* move to the platform end */
00370       TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
00371       diff *= m_tiles_skipped;
00372       m_new_tile = TILE_ADD(m_new_tile, diff);
00373       return true;
00374     }
00375 
00376     return true;
00377   }
00378 
00380   FORCEINLINE bool ForcedReverse()
00381   {
00382     /* rail and road depots cause reversing */
00383     if (!IsWaterTT() && IsDepotTypeTile(m_old_tile, TT())) {
00384       DiagDirection exitdir = IsRailTT() ? GetRailDepotDirection(m_old_tile) : GetRoadDepotDirection(m_old_tile);
00385       if (exitdir != m_exitdir) {
00386         /* reverse */
00387         m_new_tile = m_old_tile;
00388         m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
00389         m_exitdir = exitdir;
00390         m_tiles_skipped = 0;
00391         m_is_tunnel = m_is_bridge = m_is_station = false;
00392         return true;
00393       }
00394     }
00395 
00396     /* single tram bits cause reversing */
00397     if (IsTram() && GetSingleTramBit(m_old_tile) == ReverseDiagDir(m_exitdir)) {
00398       /* reverse */
00399       m_new_tile = m_old_tile;
00400       m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
00401       m_exitdir = ReverseDiagDir(m_exitdir);
00402       m_tiles_skipped = 0;
00403       m_is_tunnel = m_is_bridge = m_is_station = false;
00404       return true;
00405     }
00406 
00407     return false;
00408   }
00409 
00411   FORCEINLINE bool TryReverse()
00412   {
00413     if (IsRoadTT() && !IsTram()) {
00414       /* if we reached the end of road, we can reverse the RV and continue moving */
00415       m_exitdir = ReverseDiagDir(m_exitdir);
00416       /* new tile will be the same as old one */
00417       m_new_tile = m_old_tile;
00418       /* set new trackdir bits to all reachable trackdirs */
00419       QueryNewTileTrackStatus();
00420       m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
00421       if (m_new_td_bits != TRACKDIR_BIT_NONE) {
00422         /* we have some trackdirs reachable after reversal */
00423         return true;
00424       }
00425     }
00426     m_err = EC_NO_WAY;
00427     return false;
00428   }
00429 
00430 public:
00432   int GetSpeedLimit(int *pmin_speed = NULL) const
00433   {
00434     int min_speed = 0;
00435     int max_speed = INT_MAX; // no limit
00436 
00437     /* for now we handle only on-bridge speed limit */
00438     if (!IsWaterTT() && IsBridgeTile(m_old_tile)) {
00439       int spd = GetBridgeSpec(GetBridgeType(m_old_tile))->speed;
00440       if (IsRoadTT()) spd *= 2;
00441       if (max_speed > spd) max_speed = spd;
00442     }
00443 
00444     /* if min speed was requested, return it */
00445     if (pmin_speed) *pmin_speed = min_speed;
00446     return max_speed;
00447   }
00448 };
00449 
00450 typedef CFollowTrackT<TRANSPORT_WATER, Ship,        true > CFollowTrackWater;
00451 typedef CFollowTrackT<TRANSPORT_ROAD,  RoadVehicle, true > CFollowTrackRoad;
00452 typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       true > CFollowTrackRail;
00453 
00454 typedef CFollowTrackT<TRANSPORT_WATER, Ship,        false> CFollowTrackWaterNo90;
00455 typedef CFollowTrackT<TRANSPORT_ROAD,  RoadVehicle, false> CFollowTrackRoadNo90;
00456 typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       false> CFollowTrackRailNo90;
00457 
00458 typedef CFollowTrackT<TRANSPORT_RAIL, Train, true,  true > CFollowTrackFreeRail;
00459 typedef CFollowTrackT<TRANSPORT_RAIL, Train, false, true > CFollowTrackFreeRailNo90;
00460 
00461 #endif /* FOLLOW_TRACK_HPP */

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