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 "../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 "../infrastructure_func.h"
00023 #include "pf_performance_timer.hpp"
00024 
00030 template <TransportType Ttr_type_, typename VehicleType, bool T90deg_turns_allowed_ = true, bool Tmask_reserved_tracks = false>
00031 struct CFollowTrackT
00032 {
00033   enum ErrorCode {
00034     EC_NONE,
00035     EC_OWNER,
00036     EC_RAIL_TYPE,
00037     EC_90DEG,
00038     EC_NO_WAY,
00039     EC_RESERVED,
00040   };
00041 
00042   const VehicleType  *m_veh;           
00043   Owner               m_veh_owner;     
00044   TileIndex           m_old_tile;      
00045   Trackdir            m_old_td;        
00046   TileIndex           m_new_tile;      
00047   TrackdirBits        m_new_td_bits;   
00048   DiagDirection       m_exitdir;       
00049   bool                m_is_tunnel;     
00050   bool                m_is_bridge;     
00051   bool                m_is_station;    
00052   int                 m_tiles_skipped; 
00053   ErrorCode           m_err;
00054   CPerformanceTimer  *m_pPerf;
00055   RailTypes           m_railtypes;
00056 
00057   FORCEINLINE CFollowTrackT(const VehicleType *v = NULL, RailTypes railtype_override = INVALID_RAILTYPES, CPerformanceTimer *pPerf = NULL)
00058   {
00059     Init(v, railtype_override, pPerf);
00060   }
00061 
00062   FORCEINLINE CFollowTrackT(Owner o, RailTypes railtype_override = INVALID_RAILTYPES, CPerformanceTimer *pPerf = NULL)
00063   {
00064     m_veh = NULL;
00065     Init(o, railtype_override, pPerf);
00066   }
00067 
00068   FORCEINLINE void Init(const VehicleType *v, RailTypes railtype_override, CPerformanceTimer *pPerf)
00069   {
00070     assert(!IsRailTT() || (v != NULL && v->type == VEH_TRAIN));
00071     m_veh = v;
00072     Init(v != NULL ? v->owner : INVALID_OWNER, IsRailTT() && railtype_override == INVALID_RAILTYPES ? Train::From(v)->compatible_railtypes : railtype_override, pPerf);
00073   }
00074 
00075   FORCEINLINE void Init(Owner o, RailTypes railtype_override, CPerformanceTimer *pPerf)
00076   {
00077     assert((!IsRoadTT() || m_veh != NULL) && (!IsRailTT() || railtype_override != INVALID_RAILTYPES));
00078     m_veh_owner = o;
00079     m_pPerf = pPerf;
00080     /* don't worry, all is inlined so compiler should remove unnecessary initializations */
00081     m_new_tile = INVALID_TILE;
00082     m_new_td_bits = TRACKDIR_BIT_NONE;
00083     m_exitdir = INVALID_DIAGDIR;
00084     m_is_station = m_is_bridge = m_is_tunnel = false;
00085     m_tiles_skipped = 0;
00086     m_err = EC_NONE;
00087     m_railtypes = railtype_override;
00088   }
00089 
00090   FORCEINLINE static TransportType TT() {return Ttr_type_;}
00091   FORCEINLINE static bool IsWaterTT() {return TT() == TRANSPORT_WATER;}
00092   FORCEINLINE static bool IsRailTT() {return TT() == TRANSPORT_RAIL;}
00093   FORCEINLINE bool IsTram() {return IsRoadTT() && HasBit(RoadVehicle::From(m_veh)->compatible_roadtypes, ROADTYPE_TRAM);}
00094   FORCEINLINE static bool IsRoadTT() {return TT() == TRANSPORT_ROAD;}
00095   FORCEINLINE static bool Allow90degTurns() {return T90deg_turns_allowed_;}
00096   FORCEINLINE static bool DoTrackMasking() {return IsRailTT() && Tmask_reserved_tracks;}
00097 
00099   FORCEINLINE DiagDirection GetSingleTramBit(TileIndex tile)
00100   {
00101     assert(IsTram()); // this function shouldn't be called in other cases
00102 
00103     if (IsNormalRoadTile(tile)) {
00104       RoadBits rb = GetRoadBits(tile, ROADTYPE_TRAM);
00105       switch (rb) {
00106         case ROAD_NW: return DIAGDIR_NW;
00107         case ROAD_SW: return DIAGDIR_SW;
00108         case ROAD_SE: return DIAGDIR_SE;
00109         case ROAD_NE: return DIAGDIR_NE;
00110         default: break;
00111       }
00112     }
00113     return INVALID_DIAGDIR;
00114   }
00115 
00120   inline bool Follow(TileIndex old_tile, Trackdir old_td)
00121   {
00122     m_old_tile = old_tile;
00123     m_old_td = old_td;
00124     m_err = EC_NONE;
00125     assert(((TrackStatusToTrackdirBits(GetTileTrackStatus(m_old_tile, TT(), IsRoadTT() && m_veh != NULL ? RoadVehicle::From(m_veh)->compatible_roadtypes : 0)) & TrackdirToTrackdirBits(m_old_td)) != 0) ||
00126            (IsTram() && GetSingleTramBit(m_old_tile) != INVALID_DIAGDIR)); // Disable the assertion for single tram bits
00127     m_exitdir = TrackdirToExitdir(m_old_td);
00128     if (ForcedReverse()) return true;
00129     if (!CanExitOldTile()) return false;
00130     FollowTileExit();
00131     if (!QueryNewTileTrackStatus()) return TryReverse();
00132     if (!CanEnterNewTile()) return false;
00133     m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
00134     if (m_new_td_bits == TRACKDIR_BIT_NONE) {
00135       /* In case we can't enter the next tile, but are
00136        * a normal road vehicle, then we can actually
00137        * try to reverse as this is the end of the road.
00138        * Trams can only turn on the appropriate bits in
00139        * which case reaching this would mean a dead end
00140        * near a building and in that case there would
00141        * a "false" QueryNewTileTrackStatus result and
00142        * as such reversing is already tried. The fact
00143        * that function failed can have to do with a
00144        * missing road bit, or inability to connect the
00145        * different bits due to slopes. */
00146       if (IsRoadTT() && !IsTram() && TryReverse()) return true;
00147       m_err = EC_NO_WAY;
00148       return false;
00149     }
00150     if (!Allow90degTurns()) {
00151       m_new_td_bits &= (TrackdirBits)~(int)TrackdirCrossesTrackdirs(m_old_td);
00152       if (m_new_td_bits == TRACKDIR_BIT_NONE) {
00153         m_err = EC_90DEG;
00154         return false;
00155       }
00156     }
00157     return true;
00158   }
00159 
00160   inline bool MaskReservedTracks()
00161   {
00162     if (!DoTrackMasking()) return true;
00163 
00164     if (m_is_station) {
00165       /* Check skipped station tiles as well. */
00166       TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
00167       for (TileIndex tile = m_new_tile - diff * m_tiles_skipped; tile != m_new_tile; tile += diff) {
00168         if (HasStationReservation(tile)) {
00169           m_new_td_bits = TRACKDIR_BIT_NONE;
00170           m_err = EC_RESERVED;
00171           return false;
00172         }
00173       }
00174     }
00175 
00176     TrackBits reserved = GetReservedTrackbits(m_new_tile);
00177     /* Mask already reserved trackdirs. */
00178     m_new_td_bits &= ~TrackBitsToTrackdirBits(reserved);
00179     /* Mask out all trackdirs that conflict with the reservation. */
00180     Track t;
00181     FOR_EACH_SET_TRACK(t, TrackdirBitsToTrackBits(m_new_td_bits)) {
00182       if (TracksOverlap(reserved | TrackToTrackBits(t))) m_new_td_bits &= ~TrackToTrackdirBits(t);
00183     }
00184     if (m_new_td_bits == TRACKDIR_BIT_NONE) {
00185       m_err = EC_RESERVED;
00186       return false;
00187     }
00188     return true;
00189   }
00190 
00191 protected:
00193   FORCEINLINE void FollowTileExit()
00194   {
00195     m_is_station = m_is_bridge = m_is_tunnel = false;
00196     m_tiles_skipped = 0;
00197 
00198     /* extra handling for tunnels and bridges in our direction */
00199     if (IsTileType(m_old_tile, MP_TUNNELBRIDGE)) {
00200       DiagDirection enterdir = GetTunnelBridgeDirection(m_old_tile);
00201       if (enterdir == m_exitdir) {
00202         /* we are entering the tunnel / bridge */
00203         if (IsTunnel(m_old_tile)) {
00204           m_is_tunnel = true;
00205           m_new_tile = GetOtherTunnelEnd(m_old_tile);
00206         } else { // IsBridge(m_old_tile)
00207           m_is_bridge = true;
00208           m_new_tile = GetOtherBridgeEnd(m_old_tile);
00209         }
00210         m_tiles_skipped = GetTunnelBridgeLength(m_new_tile, m_old_tile);
00211         return;
00212       }
00213       assert(ReverseDiagDir(enterdir) == m_exitdir);
00214     }
00215 
00216     /* normal or station tile, do one step */
00217     TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
00218     m_new_tile = TILE_ADD(m_old_tile, diff);
00219 
00220     /* special handling for stations */
00221     if (IsRailTT() && HasStationTileRail(m_new_tile)) {
00222       m_is_station = true;
00223     } else if (IsRoadTT() && IsRoadStopTile(m_new_tile)) {
00224       m_is_station = true;
00225     } else {
00226       m_is_station = false;
00227     }
00228   }
00229 
00231   FORCEINLINE bool QueryNewTileTrackStatus()
00232   {
00233     CPerfStart perf(*m_pPerf);
00234     if (IsRailTT() && IsPlainRailTile(m_new_tile)) {
00235       m_new_td_bits = (TrackdirBits)(GetTrackBits(m_new_tile) * 0x101);
00236     } else {
00237       m_new_td_bits = TrackStatusToTrackdirBits(GetTileTrackStatus(m_new_tile, TT(), IsRoadTT() && m_veh != NULL ? RoadVehicle::From(m_veh)->compatible_roadtypes : 0));
00238 
00239       if (IsTram() && m_new_td_bits == 0) {
00240         /* GetTileTrackStatus() returns 0 for single tram bits.
00241          * As we cannot change it there (easily) without breaking something, change it here */
00242         switch (GetSingleTramBit(m_new_tile)) {
00243           case DIAGDIR_NE:
00244           case DIAGDIR_SW:
00245             m_new_td_bits = TRACKDIR_BIT_X_NE | TRACKDIR_BIT_X_SW;
00246             break;
00247 
00248           case DIAGDIR_NW:
00249           case DIAGDIR_SE:
00250             m_new_td_bits = TRACKDIR_BIT_Y_NW | TRACKDIR_BIT_Y_SE;
00251             break;
00252 
00253           default: break;
00254         }
00255       }
00256     }
00257     return (m_new_td_bits != TRACKDIR_BIT_NONE);
00258   }
00259 
00261   FORCEINLINE bool CanExitOldTile()
00262   {
00263     /* road stop can be left at one direction only unless it's a drive-through stop */
00264     if (IsRoadTT() && IsStandardRoadStopTile(m_old_tile)) {
00265       DiagDirection exitdir = GetRoadStopDir(m_old_tile);
00266       if (exitdir != m_exitdir) {
00267         m_err = EC_NO_WAY;
00268         return false;
00269       }
00270     }
00271 
00272     /* single tram bits can only be left in one direction */
00273     if (IsTram()) {
00274       DiagDirection single_tram = GetSingleTramBit(m_old_tile);
00275       if (single_tram != INVALID_DIAGDIR && single_tram != m_exitdir) {
00276         m_err = EC_NO_WAY;
00277         return false;
00278       }
00279     }
00280 
00281     /* road depots can be also left in one direction only */
00282     if (IsRoadTT() && IsDepotTypeTile(m_old_tile, TT())) {
00283       DiagDirection exitdir = GetRoadDepotDirection(m_old_tile);
00284       if (exitdir != m_exitdir) {
00285         m_err = EC_NO_WAY;
00286         return false;
00287       }
00288     }
00289     return true;
00290   }
00291 
00293   FORCEINLINE bool CanEnterNewTile()
00294   {
00295     if (IsRoadTT() && IsStandardRoadStopTile(m_new_tile)) {
00296       /* road stop can be entered from one direction only unless it's a drive-through stop */
00297       DiagDirection exitdir = GetRoadStopDir(m_new_tile);
00298       if (ReverseDiagDir(exitdir) != m_exitdir) {
00299         m_err = EC_NO_WAY;
00300         return false;
00301       }
00302       /* road stops shouldn't be entered unless allowed to */
00303       if (!IsInfraTileUsageAllowed(VEH_ROAD, m_veh_owner, m_new_tile)) {
00304         m_err = EC_OWNER;
00305         return false;
00306       }
00307     }
00308 
00309     /* single tram bits can only be entered from one direction */
00310     if (IsTram()) {
00311       DiagDirection single_tram = GetSingleTramBit(m_new_tile);
00312       if (single_tram != INVALID_DIAGDIR && single_tram != ReverseDiagDir(m_exitdir)) {
00313         m_err = EC_NO_WAY;
00314         return false;
00315       }
00316     }
00317 
00318     /* road and rail depots can also be entered from one direction only */
00319     if (IsRoadTT() && IsDepotTypeTile(m_new_tile, TT())) {
00320       DiagDirection exitdir = GetRoadDepotDirection(m_new_tile);
00321       if (ReverseDiagDir(exitdir) != m_exitdir) {
00322         m_err = EC_NO_WAY;
00323         return false;
00324       }
00325       /* don't try to enter other company's depots if not allowed */
00326       if (!IsInfraTileUsageAllowed(VEH_ROAD, m_veh_owner, m_new_tile)) {
00327         m_err = EC_OWNER;
00328         return false;
00329       }
00330     }
00331     if (IsRailTT() && IsDepotTypeTile(m_new_tile, TT())) {
00332       DiagDirection exitdir = GetRailDepotDirection(m_new_tile);
00333       if (ReverseDiagDir(exitdir) != m_exitdir) {
00334         m_err = EC_NO_WAY;
00335         return false;
00336       }
00337     }
00338 
00339     /* rail transport is possible only on allowed tiles */
00340     if (IsRailTT() && !IsInfraTileUsageAllowed(VEH_TRAIN, m_veh_owner, m_new_tile)) {
00341       /* different owner */
00342       m_err = EC_NO_WAY;
00343       return false;
00344     }
00345 
00346     /* rail transport is possible only on compatible rail types */
00347     if (IsRailTT()) {
00348       RailType rail_type = GetTileRailType(m_new_tile);
00349       if (!HasBit(m_railtypes, rail_type)) {
00350         /* incompatible rail type */
00351         m_err = EC_RAIL_TYPE;
00352         return false;
00353       }
00354     }
00355 
00356     /* tunnel holes and bridge ramps can be entered only from proper direction */
00357     if (IsTileType(m_new_tile, MP_TUNNELBRIDGE)) {
00358       if (IsTunnel(m_new_tile)) {
00359         if (!m_is_tunnel) {
00360           DiagDirection tunnel_enterdir = GetTunnelBridgeDirection(m_new_tile);
00361           if (tunnel_enterdir != m_exitdir || IsTunnelBridgeExit(m_new_tile)) {
00362             m_err = EC_NO_WAY;
00363             return false;
00364           }
00365         }
00366       } else { // IsBridge(m_new_tile)
00367         if (!m_is_bridge) {
00368           DiagDirection ramp_enderdir = GetTunnelBridgeDirection(m_new_tile);
00369           if (ramp_enderdir != m_exitdir || IsTunnelBridgeExit(m_new_tile)) {
00370             m_err = EC_NO_WAY;
00371             return false;
00372           }
00373         }
00374       }
00375     }
00376 
00377     /* special handling for rail stations - get to the end of platform */
00378     if (IsRailTT() && m_is_station) {
00379       /* entered railway station
00380        * get platform length */
00381       uint length = BaseStation::GetByTile(m_new_tile)->GetPlatformLength(m_new_tile, TrackdirToExitdir(m_old_td));
00382       /* how big step we must do to get to the last platform tile; */
00383       m_tiles_skipped = length - 1;
00384       /* move to the platform end */
00385       TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
00386       diff *= m_tiles_skipped;
00387       m_new_tile = TILE_ADD(m_new_tile, diff);
00388       return true;
00389     }
00390 
00391     return true;
00392   }
00393 
00395   FORCEINLINE bool ForcedReverse()
00396   {
00397     /* rail and road depots cause reversing */
00398     if (!IsWaterTT() && IsDepotTypeTile(m_old_tile, TT())) {
00399       DiagDirection exitdir = IsRailTT() ? GetRailDepotDirection(m_old_tile) : GetRoadDepotDirection(m_old_tile);
00400       if (exitdir != m_exitdir) {
00401         /* reverse */
00402         m_new_tile = m_old_tile;
00403         m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
00404         m_exitdir = exitdir;
00405         m_tiles_skipped = 0;
00406         m_is_tunnel = m_is_bridge = m_is_station = false;
00407         return true;
00408       }
00409     }
00410 
00411     /* single tram bits cause reversing */
00412     if (IsTram() && GetSingleTramBit(m_old_tile) == ReverseDiagDir(m_exitdir)) {
00413       /* reverse */
00414       m_new_tile = m_old_tile;
00415       m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
00416       m_exitdir = ReverseDiagDir(m_exitdir);
00417       m_tiles_skipped = 0;
00418       m_is_tunnel = m_is_bridge = m_is_station = false;
00419       return true;
00420     }
00421 
00422     return false;
00423   }
00424 
00426   FORCEINLINE bool TryReverse()
00427   {
00428     if (IsRoadTT() && !IsTram()) {
00429       /* if we reached the end of road, we can reverse the RV and continue moving */
00430       m_exitdir = ReverseDiagDir(m_exitdir);
00431       /* new tile will be the same as old one */
00432       m_new_tile = m_old_tile;
00433       /* set new trackdir bits to all reachable trackdirs */
00434       QueryNewTileTrackStatus();
00435       m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
00436       if (m_new_td_bits != TRACKDIR_BIT_NONE) {
00437         /* we have some trackdirs reachable after reversal */
00438         return true;
00439       }
00440     }
00441     m_err = EC_NO_WAY;
00442     return false;
00443   }
00444 
00445 public:
00447   int GetSpeedLimit(int *pmin_speed = NULL) const
00448   {
00449     int min_speed = 0;
00450     int max_speed = INT_MAX; // no limit
00451 
00452     /* Check for on-bridge speed limit */
00453     if (!IsWaterTT() && IsBridgeTile(m_old_tile)) {
00454       int spd = GetBridgeSpec(GetBridgeType(m_old_tile))->speed;
00455       if (IsRoadTT()) spd *= 2;
00456       if (max_speed > spd) max_speed = spd;
00457     }
00458     /* Check for speed limit imposed by railtype */
00459     if (IsRailTT()) {
00460       uint16 rail_speed = GetRailTypeInfo(GetRailType(m_old_tile))->max_speed;
00461       if (rail_speed > 0) max_speed = min(max_speed, rail_speed);
00462     }
00463 
00464     /* if min speed was requested, return it */
00465     if (pmin_speed != NULL) *pmin_speed = min_speed;
00466     return max_speed;
00467   }
00468 };
00469 
00470 typedef CFollowTrackT<TRANSPORT_WATER, Ship,        true > CFollowTrackWater;
00471 typedef CFollowTrackT<TRANSPORT_ROAD,  RoadVehicle, true > CFollowTrackRoad;
00472 typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       true > CFollowTrackRail;
00473 
00474 typedef CFollowTrackT<TRANSPORT_WATER, Ship,        false> CFollowTrackWaterNo90;
00475 typedef CFollowTrackT<TRANSPORT_ROAD,  RoadVehicle, false> CFollowTrackRoadNo90;
00476 typedef CFollowTrackT<TRANSPORT_RAIL,  Train,       false> CFollowTrackRailNo90;
00477 
00478 typedef CFollowTrackT<TRANSPORT_RAIL, Train, true,  true > CFollowTrackFreeRail;
00479 typedef CFollowTrackT<TRANSPORT_RAIL, Train, false, true > CFollowTrackFreeRailNo90;
00480 
00481 #endif /* FOLLOW_TRACK_HPP */