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 */

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