follow_track.hpp

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00001 /* $Id: follow_track.hpp 21229 2010-11-17 23:07:53Z 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   FORCEINLINE CFollowTrackT(const VehicleType *v = NULL, RailTypes railtype_override = INVALID_RAILTYPES, CPerformanceTimer *pPerf = NULL)
00057   {
00058     Init(v, railtype_override, pPerf);
00059   }
00060 
00061   FORCEINLINE 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   FORCEINLINE 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   FORCEINLINE 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_new_tile = INVALID_TILE;
00081     m_new_td_bits = TRACKDIR_BIT_NONE;
00082     m_exitdir = INVALID_DIAGDIR;
00083     m_is_station = m_is_bridge = m_is_tunnel = false;
00084     m_tiles_skipped = 0;
00085     m_err = EC_NONE;
00086     m_railtypes = railtype_override;
00087   }
00088 
00089   FORCEINLINE static TransportType TT() {return Ttr_type_;}
00090   FORCEINLINE static bool IsWaterTT() {return TT() == TRANSPORT_WATER;}
00091   FORCEINLINE static bool IsRailTT() {return TT() == TRANSPORT_RAIL;}
00092   FORCEINLINE bool IsTram() {return IsRoadTT() && HasBit(RoadVehicle::From(m_veh)->compatible_roadtypes, ROADTYPE_TRAM);}
00093   FORCEINLINE static bool IsRoadTT() {return TT() == TRANSPORT_ROAD;}
00094   FORCEINLINE static bool Allow90degTurns() {return T90deg_turns_allowed_;}
00095   FORCEINLINE static bool DoTrackMasking() {return IsRailTT() && Tmask_reserved_tracks;}
00096 
00098   FORCEINLINE DiagDirection GetSingleTramBit(TileIndex tile)
00099   {
00100     assert(IsTram()); // this function shouldn't be called in other cases
00101 
00102     if (IsNormalRoadTile(tile)) {
00103       RoadBits rb = GetRoadBits(tile, ROADTYPE_TRAM);
00104       switch (rb) {
00105         case ROAD_NW: return DIAGDIR_NW;
00106         case ROAD_SW: return DIAGDIR_SW;
00107         case ROAD_SE: return DIAGDIR_SE;
00108         case ROAD_NE: return DIAGDIR_NE;
00109         default: break;
00110       }
00111     }
00112     return INVALID_DIAGDIR;
00113   }
00114 
00119   inline bool Follow(TileIndex old_tile, Trackdir old_td)
00120   {
00121     m_old_tile = old_tile;
00122     m_old_td = old_td;
00123     m_err = EC_NONE;
00124     assert(((TrackStatusToTrackdirBits(GetTileTrackStatus(m_old_tile, TT(), IsRoadTT() && m_veh != NULL ? RoadVehicle::From(m_veh)->compatible_roadtypes : 0)) & TrackdirToTrackdirBits(m_old_td)) != 0) ||
00125            (IsTram() && GetSingleTramBit(m_old_tile) != INVALID_DIAGDIR)); // Disable the assertion for single tram bits
00126     m_exitdir = TrackdirToExitdir(m_old_td);
00127     if (ForcedReverse()) return true;
00128     if (!CanExitOldTile()) return false;
00129     FollowTileExit();
00130     if (!QueryNewTileTrackStatus()) return TryReverse();
00131     if (!CanEnterNewTile()) return false;
00132     m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
00133     if (m_new_td_bits == TRACKDIR_BIT_NONE) {
00134       /* In case we can't enter the next tile, but are
00135        * a normal road vehicle, then we can actually
00136        * try to reverse as this is the end of the road.
00137        * Trams can only turn on the appropriate bits in
00138        * which case reaching this would mean a dead end
00139        * near a building and in that case there would
00140        * a "false" QueryNewTileTrackStatus result and
00141        * as such reversing is already tried. The fact
00142        * that function failed can have to do with a
00143        * missing road bit, or inability to connect the
00144        * different bits due to slopes. */
00145       if (IsRoadTT() && !IsTram() && TryReverse()) return true;
00146       m_err = EC_NO_WAY;
00147       return false;
00148     }
00149     if (!Allow90degTurns()) {
00150       m_new_td_bits &= (TrackdirBits)~(int)TrackdirCrossesTrackdirs(m_old_td);
00151       if (m_new_td_bits == TRACKDIR_BIT_NONE) {
00152         m_err = EC_90DEG;
00153         return false;
00154       }
00155     }
00156     return true;
00157   }
00158 
00159   inline bool MaskReservedTracks()
00160   {
00161     if (!DoTrackMasking()) return true;
00162 
00163     if (m_is_station) {
00164       /* Check skipped station tiles as well. */
00165       TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
00166       for (TileIndex tile = m_new_tile - diff * m_tiles_skipped; tile != m_new_tile; tile += diff) {
00167         if (HasStationReservation(tile)) {
00168           m_new_td_bits = TRACKDIR_BIT_NONE;
00169           m_err = EC_RESERVED;
00170           return false;
00171         }
00172       }
00173     }
00174 
00175     TrackBits reserved = GetReservedTrackbits(m_new_tile);
00176     /* Mask already reserved trackdirs. */
00177     m_new_td_bits &= ~TrackBitsToTrackdirBits(reserved);
00178     /* Mask out all trackdirs that conflict with the reservation. */
00179     Track t;
00180     FOR_EACH_SET_TRACK(t, TrackdirBitsToTrackBits(m_new_td_bits)) {
00181       if (TracksOverlap(reserved | TrackToTrackBits(t))) m_new_td_bits &= ~TrackToTrackdirBits(t);
00182     }
00183     if (m_new_td_bits == TRACKDIR_BIT_NONE) {
00184       m_err = EC_RESERVED;
00185       return false;
00186     }
00187     return true;
00188   }
00189 
00190 protected:
00192   FORCEINLINE void FollowTileExit()
00193   {
00194     m_is_station = m_is_bridge = m_is_tunnel = false;
00195     m_tiles_skipped = 0;
00196 
00197     /* extra handling for tunnels and bridges in our direction */
00198     if (IsTileType(m_old_tile, MP_TUNNELBRIDGE)) {
00199       DiagDirection enterdir = GetTunnelBridgeDirection(m_old_tile);
00200       if (enterdir == m_exitdir) {
00201         /* we are entering the tunnel / bridge */
00202         if (IsTunnel(m_old_tile)) {
00203           m_is_tunnel = true;
00204           m_new_tile = GetOtherTunnelEnd(m_old_tile);
00205         } else { // IsBridge(m_old_tile)
00206           m_is_bridge = true;
00207           m_new_tile = GetOtherBridgeEnd(m_old_tile);
00208         }
00209         m_tiles_skipped = GetTunnelBridgeLength(m_new_tile, m_old_tile);
00210         return;
00211       }
00212       assert(ReverseDiagDir(enterdir) == m_exitdir);
00213     }
00214 
00215     /* normal or station tile, do one step */
00216     TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
00217     m_new_tile = TILE_ADD(m_old_tile, diff);
00218 
00219     /* special handling for stations */
00220     if (IsRailTT() && HasStationTileRail(m_new_tile)) {
00221       m_is_station = true;
00222     } else if (IsRoadTT() && IsRoadStopTile(m_new_tile)) {
00223       m_is_station = true;
00224     } else {
00225       m_is_station = false;
00226     }
00227   }
00228 
00230   FORCEINLINE bool QueryNewTileTrackStatus()
00231   {
00232     CPerfStart perf(*m_pPerf);
00233     if (IsRailTT() && IsPlainRailTile(m_new_tile)) {
00234       m_new_td_bits = (TrackdirBits)(GetTrackBits(m_new_tile) * 0x101);
00235     } else {
00236       m_new_td_bits = TrackStatusToTrackdirBits(GetTileTrackStatus(m_new_tile, TT(), IsRoadTT() && m_veh != NULL ? RoadVehicle::From(m_veh)->compatible_roadtypes : 0));
00237 
00238       if (IsTram() && m_new_td_bits == 0) {
00239         /* GetTileTrackStatus() returns 0 for single tram bits.
00240          * As we cannot change it there (easily) without breaking something, change it here */
00241         switch (GetSingleTramBit(m_new_tile)) {
00242           case DIAGDIR_NE:
00243           case DIAGDIR_SW:
00244             m_new_td_bits = TRACKDIR_BIT_X_NE | TRACKDIR_BIT_X_SW;
00245             break;
00246 
00247           case DIAGDIR_NW:
00248           case DIAGDIR_SE:
00249             m_new_td_bits = TRACKDIR_BIT_Y_NW | TRACKDIR_BIT_Y_SE;
00250             break;
00251 
00252           default: break;
00253         }
00254       }
00255     }
00256     return (m_new_td_bits != TRACKDIR_BIT_NONE);
00257   }
00258 
00260   FORCEINLINE bool CanExitOldTile()
00261   {
00262     /* road stop can be left at one direction only unless it's a drive-through stop */
00263     if (IsRoadTT() && IsStandardRoadStopTile(m_old_tile)) {
00264       DiagDirection exitdir = GetRoadStopDir(m_old_tile);
00265       if (exitdir != m_exitdir) {
00266         m_err = EC_NO_WAY;
00267         return false;
00268       }
00269     }
00270 
00271     /* single tram bits can only be left in one direction */
00272     if (IsTram()) {
00273       DiagDirection single_tram = GetSingleTramBit(m_old_tile);
00274       if (single_tram != INVALID_DIAGDIR && single_tram != m_exitdir) {
00275         m_err = EC_NO_WAY;
00276         return false;
00277       }
00278     }
00279 
00280     /* road depots can be also left in one direction only */
00281     if (IsRoadTT() && IsDepotTypeTile(m_old_tile, TT())) {
00282       DiagDirection exitdir = GetRoadDepotDirection(m_old_tile);
00283       if (exitdir != m_exitdir) {
00284         m_err = EC_NO_WAY;
00285         return false;
00286       }
00287     }
00288     return true;
00289   }
00290 
00292   FORCEINLINE bool CanEnterNewTile()
00293   {
00294     if (IsRoadTT() && IsStandardRoadStopTile(m_new_tile)) {
00295       /* road stop can be entered from one direction only unless it's a drive-through stop */
00296       DiagDirection exitdir = GetRoadStopDir(m_new_tile);
00297       if (ReverseDiagDir(exitdir) != m_exitdir) {
00298         m_err = EC_NO_WAY;
00299         return false;
00300       }
00301     }
00302 
00303     /* single tram bits can only be entered from one direction */
00304     if (IsTram()) {
00305       DiagDirection single_tram = GetSingleTramBit(m_new_tile);
00306       if (single_tram != INVALID_DIAGDIR && single_tram != ReverseDiagDir(m_exitdir)) {
00307         m_err = EC_NO_WAY;
00308         return false;
00309       }
00310     }
00311 
00312     /* road and rail depots can also be entered from one direction only */
00313     if (IsRoadTT() && IsDepotTypeTile(m_new_tile, TT())) {
00314       DiagDirection exitdir = GetRoadDepotDirection(m_new_tile);
00315       if (ReverseDiagDir(exitdir) != m_exitdir) {
00316         m_err = EC_NO_WAY;
00317         return false;
00318       }
00319       /* don't try to enter other company's depots */
00320       if (GetTileOwner(m_new_tile) != m_veh_owner) {
00321         m_err = EC_OWNER;
00322         return false;
00323       }
00324     }
00325     if (IsRailTT() && IsDepotTypeTile(m_new_tile, TT())) {
00326       DiagDirection exitdir = GetRailDepotDirection(m_new_tile);
00327       if (ReverseDiagDir(exitdir) != m_exitdir) {
00328         m_err = EC_NO_WAY;
00329         return false;
00330       }
00331     }
00332 
00333     /* rail transport is possible only on tiles with the same owner as vehicle */
00334     if (IsRailTT() && GetTileOwner(m_new_tile) != m_veh_owner) {
00335       /* different owner */
00336       m_err = EC_NO_WAY;
00337       return false;
00338     }
00339 
00340     /* rail transport is possible only on compatible rail types */
00341     if (IsRailTT()) {
00342       RailType rail_type = GetTileRailType(m_new_tile);
00343       if (!HasBit(m_railtypes, rail_type)) {
00344         /* incompatible rail type */
00345         m_err = EC_RAIL_TYPE;
00346         return false;
00347       }
00348     }
00349 
00350     /* tunnel holes and bridge ramps can be entered only from proper direction */
00351     if (IsTileType(m_new_tile, MP_TUNNELBRIDGE)) {
00352       if (IsTunnel(m_new_tile)) {
00353         if (!m_is_tunnel) {
00354           DiagDirection tunnel_enterdir = GetTunnelBridgeDirection(m_new_tile);
00355           if (tunnel_enterdir != m_exitdir) {
00356             m_err = EC_NO_WAY;
00357             return false;
00358           }
00359         }
00360       } else { // IsBridge(m_new_tile)
00361         if (!m_is_bridge) {
00362           DiagDirection ramp_enderdir = GetTunnelBridgeDirection(m_new_tile);
00363           if (ramp_enderdir != m_exitdir) {
00364             m_err = EC_NO_WAY;
00365             return false;
00366           }
00367         }
00368       }
00369     }
00370 
00371     /* special handling for rail stations - get to the end of platform */
00372     if (IsRailTT() && m_is_station) {
00373       /* entered railway station
00374        * get platform length */
00375       uint length = BaseStation::GetByTile(m_new_tile)->GetPlatformLength(m_new_tile, TrackdirToExitdir(m_old_td));
00376       /* how big step we must do to get to the last platform tile; */
00377       m_tiles_skipped = length - 1;
00378       /* move to the platform end */
00379       TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
00380       diff *= m_tiles_skipped;
00381       m_new_tile = TILE_ADD(m_new_tile, diff);
00382       return true;
00383     }
00384 
00385     return true;
00386   }
00387 
00389   FORCEINLINE bool ForcedReverse()
00390   {
00391     /* rail and road depots cause reversing */
00392     if (!IsWaterTT() && IsDepotTypeTile(m_old_tile, TT())) {
00393       DiagDirection exitdir = IsRailTT() ? GetRailDepotDirection(m_old_tile) : GetRoadDepotDirection(m_old_tile);
00394       if (exitdir != m_exitdir) {
00395         /* reverse */
00396         m_new_tile = m_old_tile;
00397         m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
00398         m_exitdir = exitdir;
00399         m_tiles_skipped = 0;
00400         m_is_tunnel = m_is_bridge = m_is_station = false;
00401         return true;
00402       }
00403     }
00404 
00405     /* single tram bits cause reversing */
00406     if (IsTram() && GetSingleTramBit(m_old_tile) == ReverseDiagDir(m_exitdir)) {
00407       /* reverse */
00408       m_new_tile = m_old_tile;
00409       m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
00410       m_exitdir = ReverseDiagDir(m_exitdir);
00411       m_tiles_skipped = 0;
00412       m_is_tunnel = m_is_bridge = m_is_station = false;
00413       return true;
00414     }
00415 
00416     return false;
00417   }
00418 
00420   FORCEINLINE bool TryReverse()
00421   {
00422     if (IsRoadTT() && !IsTram()) {
00423       /* if we reached the end of road, we can reverse the RV and continue moving */
00424       m_exitdir = ReverseDiagDir(m_exitdir);
00425       /* new tile will be the same as old one */
00426       m_new_tile = m_old_tile;
00427       /* set new trackdir bits to all reachable trackdirs */
00428       QueryNewTileTrackStatus();
00429       m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
00430       if (m_new_td_bits != TRACKDIR_BIT_NONE) {
00431         /* we have some trackdirs reachable after reversal */
00432         return true;
00433       }
00434     }
00435     m_err = EC_NO_WAY;
00436     return false;
00437   }
00438 
00439 public:
00441   int GetSpeedLimit(int *pmin_speed = NULL) const
00442   {
00443     int min_speed = 0;
00444     int max_speed = INT_MAX; // no limit
00445 
00446     /* Check for on-bridge speed limit */
00447     if (!IsWaterTT() && IsBridgeTile(m_old_tile)) {
00448       int spd = GetBridgeSpec(GetBridgeType(m_old_tile))->speed;
00449       if (IsRoadTT()) spd *= 2;
00450       if (max_speed > spd) max_speed = spd;
00451     }
00452     /* Check for speed limit imposed by railtype */
00453     if (IsRailTT()) {
00454       uint16 rail_speed = GetRailTypeInfo(GetRailType(m_old_tile))->max_speed;
00455       if (rail_speed > 0) max_speed = min(max_speed, rail_speed);
00456     }
00457 
00458     /* if min speed was requested, return it */
00459     if (pmin_speed) *pmin_speed = min_speed;
00460     return max_speed;
00461   }
00462 };
00463 
00464 typedef CFollowTrackT<TRANSPORT_WATER, Ship,        true > CFollowTrackWater;
00465 typedef CFollowTrackT<TRANSPORT_ROAD,  RoadVehicle, true > CFollowTrackRoad;
00466 typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       true > CFollowTrackRail;
00467 
00468 typedef CFollowTrackT<TRANSPORT_WATER, Ship,        false> CFollowTrackWaterNo90;
00469 typedef CFollowTrackT<TRANSPORT_ROAD,  RoadVehicle, false> CFollowTrackRoadNo90;
00470 typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       false> CFollowTrackRailNo90;
00471 
00472 typedef CFollowTrackT<TRANSPORT_RAIL, Train, true,  true > CFollowTrackFreeRail;
00473 typedef CFollowTrackT<TRANSPORT_RAIL, Train, false, true > CFollowTrackFreeRailNo90;
00474 
00475 #endif /* FOLLOW_TRACK_HPP */

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