# follow_track.hpp

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    00001 /* $Id: follow_track.hpp 12252 2008-02-25 15:09:22Z KUDr $ */
    00002
    00005 #ifndef  FOLLOW_TRACK_HPP
    00006 #define  FOLLOW_TRACK_HPP
    00007
    00008 #include "yapf.hpp"
    00009
    00010
    00014 template <TransportType Ttr_type_, bool T90deg_turns_allowed_ = true>
    00015 struct CFollowTrackT
    00016 {
    00017   enum ErrorCode {
    00018     EC_NONE,
    00019     EC_OWNER,
    00020     EC_RAIL_TYPE,
    00021     EC_90DEG,
    00022     EC_NO_WAY,
    00023   };
    00024
    00025   const Vehicle*      m_veh;
    00026   TileIndex           m_old_tile;
    00027   Trackdir            m_old_td;
    00028   TileIndex           m_new_tile;
    00029   TrackdirBits        m_new_td_bits;
    00030   DiagDirection       m_exitdir;
    00031   bool                m_is_tunnel;
    00032   bool                m_is_bridge;
    00033   bool                m_is_station;
    00034   int                 m_tiles_skipped;
    00035   ErrorCode           m_err;
    00036   CPerformanceTimer* m_pPerf;
    00037
    00038   FORCEINLINE CFollowTrackT(const Vehicle* v = NULL, CPerformanceTimer* pPerf = NULL)
    00039   {
    00040     Init(v, pPerf);
    00041   }
    00042
    00043   FORCEINLINE void Init(const Vehicle* v, CPerformanceTimer* pPerf)
    00044   {
    00045     assert(!IsRailTT() || (v != NULL && v->type == VEH_TRAIN));
    00046     m_veh = v;
    00047     m_pPerf = pPerf;
    00048     // don't worry, all is inlined so compiler should remove unnecessary initializations
    00049     m_new_tile = INVALID_TILE;
    00050     m_new_td_bits = TRACKDIR_BIT_NONE;
    00051     m_exitdir = INVALID_DIAGDIR;
    00052     m_is_station = m_is_bridge = m_is_tunnel = false;
    00053     m_tiles_skipped = 0;
    00054     m_err = EC_NONE;
    00055   }
    00056
    00057   FORCEINLINE static TransportType TT() {return Ttr_type_;}
    00058   FORCEINLINE static bool IsWaterTT() {return TT() == TRANSPORT_WATER;}
    00059   FORCEINLINE static bool IsRailTT() {return TT() == TRANSPORT_RAIL;}
    00060   FORCEINLINE bool IsTram() {return IsRoadTT() && HasBit(m_veh->u.road.compatible_roadtypes, ROADTYPE_TRAM);}
    00061   FORCEINLINE static bool IsRoadTT() {return TT() == TRANSPORT_ROAD;}
    00062   FORCEINLINE static bool Allow90degTurns() {return T90deg_turns_allowed_;}
    00063
    00065   FORCEINLINE DiagDirection GetSingleTramBit(TileIndex tile)
    00066   {
    00067     if (IsTram() && IsNormalRoadTile(tile)) {
    00068       RoadBits rb = GetRoadBits(tile, ROADTYPE_TRAM);
    00069       switch (rb) {
    00070         case ROAD_NW: return DIAGDIR_NW;
    00071         case ROAD_SW: return DIAGDIR_SW;
    00072         case ROAD_SE: return DIAGDIR_SE;
    00073         case ROAD_NE: return DIAGDIR_NE;
    00074         default: break;
    00075       }
    00076     }
    00077     return INVALID_DIAGDIR;
    00078   }
    00079
    00082   FORCEINLINE bool Follow(TileIndex old_tile, Trackdir old_td)
    00083   {
    00084     m_old_tile = old_tile;
    00085     m_old_td = old_td;
    00086     m_err = EC_NONE;
    00087     assert(((TrackStatusToTrackdirBits(GetTileTrackStatus(m_old_tile, TT(), m_veh->u.road.compatible_roadtypes)) & TrackdirToTrackdirBits(m_old_td)) != 0) ||
    00088            (GetSingleTramBit(m_old_tile) != INVALID_DIAGDIR)); // Disable the assertion for single tram bits
    00089     m_exitdir = TrackdirToExitdir(m_old_td);
    00090     if (ForcedReverse()) return true;
    00091     if (!CanExitOldTile()) return false;
    00092     FollowTileExit();
    00093     if (!QueryNewTileTrackStatus()) return TryReverse();
    00094     if (!CanEnterNewTile()) return false;
    00095     m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
    00096     if (m_new_td_bits == TRACKDIR_BIT_NONE) {
    00097       m_err = EC_NO_WAY;
    00098       return false;
    00099     }
    00100     if (!Allow90degTurns()) {
    00101       m_new_td_bits &= (TrackdirBits)~(int)TrackdirCrossesTrackdirs(m_old_td);
    00102       if (m_new_td_bits == TRACKDIR_BIT_NONE) {
    00103         m_err = EC_90DEG;
    00104         return false;
    00105       }
    00106     }
    00107     return true;
    00108   }
    00109
    00110 protected:
    00112   FORCEINLINE void FollowTileExit()
    00113   {
    00114     m_is_station = m_is_bridge = m_is_tunnel = false;
    00115     m_tiles_skipped = 0;
    00116
    00117     // extra handling for tunnels and bridges in our direction
    00118     if (IsTileType(m_old_tile, MP_TUNNELBRIDGE)) {
    00119       DiagDirection enterdir = GetTunnelBridgeDirection(m_old_tile);
    00120       if (enterdir == m_exitdir) {
    00121         // we are entering the tunnel / bridge
    00122         if (IsTunnel(m_old_tile)) {
    00123           m_is_tunnel = true;
    00124           m_new_tile = GetOtherTunnelEnd(m_old_tile);
    00125         } else { // IsBridge(m_old_tile)
    00126           m_is_bridge = true;
    00127           m_new_tile = GetOtherBridgeEnd(m_old_tile);
    00128         }
    00129         m_tiles_skipped = GetTunnelBridgeLength(m_new_tile, m_old_tile);
    00130         return;
    00131       }
    00132       assert(ReverseDiagDir(enterdir) == m_exitdir);
    00133     }
    00134
    00135     // normal or station tile, do one step
    00136     TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
    00137     m_new_tile = TILE_ADD(m_old_tile, diff);
    00138
    00139     // special handling for stations
    00140     if (IsRailTT() && IsRailwayStationTile(m_new_tile)) {
    00141       m_is_station = true;
    00142     } else if (IsRoadTT() && IsRoadStopTile(m_new_tile)) {
    00143       m_is_station = true;
    00144     } else {
    00145       m_is_station = false;
    00146     }
    00147   }
    00148
    00150   FORCEINLINE bool QueryNewTileTrackStatus()
    00151   {
    00152     CPerfStart perf(*m_pPerf);
    00153     if (IsRailTT() && GetTileType(m_new_tile) == MP_RAILWAY && IsPlainRailTile(m_new_tile)) {
    00154       m_new_td_bits = (TrackdirBits)(GetTrackBits(m_new_tile) * 0x101);
    00155     } else {
    00156       m_new_td_bits = TrackStatusToTrackdirBits(GetTileTrackStatus(m_new_tile, TT(), m_veh->u.road.compatible_roadtypes));
    00157
    00158       if (m_new_td_bits == 0) {
    00159         /* GetTileTrackStatus() returns 0 for single tram bits.
    00160          * As we cannot change it there (easily) without breaking something, change it here */
    00161         switch (GetSingleTramBit(m_new_tile)) {
    00162           case DIAGDIR_NE:
    00163           case DIAGDIR_SW:
    00164             m_new_td_bits = TRACKDIR_BIT_X_NE | TRACKDIR_BIT_X_SW;
    00165             break;
    00166
    00167           case DIAGDIR_NW:
    00168           case DIAGDIR_SE:
    00169             m_new_td_bits = TRACKDIR_BIT_Y_NW | TRACKDIR_BIT_Y_SE;
    00170             break;
    00171
    00172           default: break;
    00173         }
    00174       }
    00175     }
    00176     return (m_new_td_bits != TRACKDIR_BIT_NONE);
    00177   }
    00178
    00180   FORCEINLINE bool CanExitOldTile()
    00181   {
    00182     // road stop can be left at one direction only unless it's a drive-through stop
    00183     if (IsRoadTT() && IsStandardRoadStopTile(m_old_tile)) {
    00184       DiagDirection exitdir = GetRoadStopDir(m_old_tile);
    00185       if (exitdir != m_exitdir) {
    00186         m_err = EC_NO_WAY;
    00187         return false;
    00188       }
    00189     }
    00190
    00191     /* single tram bits can only be left in one direction */
    00192     DiagDirection single_tram = GetSingleTramBit(m_old_tile);
    00193     if (single_tram != INVALID_DIAGDIR && single_tram != m_exitdir) {
    00194       m_err = EC_NO_WAY;
    00195       return false;
    00196     }
    00197
    00198     // road depots can be also left in one direction only
    00199     if (IsRoadTT() && IsTileDepotType(m_old_tile, TT())) {
    00200       DiagDirection exitdir = GetRoadDepotDirection(m_old_tile);
    00201       if (exitdir != m_exitdir) {
    00202         m_err = EC_NO_WAY;
    00203         return false;
    00204       }
    00205     }
    00206     return true;
    00207   }
    00208
    00210   FORCEINLINE bool CanEnterNewTile()
    00211   {
    00212     if (IsRoadTT() && IsStandardRoadStopTile(m_new_tile)) {
    00213       // road stop can be entered from one direction only unless it's a drive-through stop
    00214       DiagDirection exitdir = GetRoadStopDir(m_new_tile);
    00215       if (ReverseDiagDir(exitdir) != m_exitdir) {
    00216         m_err = EC_NO_WAY;
    00217         return false;
    00218       }
    00219     }
    00220
    00221     /* single tram bits can only be entered from one direction */
    00222     DiagDirection single_tram = GetSingleTramBit(m_new_tile);
    00223     if (single_tram != INVALID_DIAGDIR && single_tram != ReverseDiagDir(m_exitdir)) {
    00224       m_err = EC_NO_WAY;
    00225       return false;
    00226     }
    00227
    00228     // road and rail depots can also be entered from one direction only
    00229     if (IsRoadTT() && IsTileDepotType(m_new_tile, TT())) {
    00230       DiagDirection exitdir = GetRoadDepotDirection(m_new_tile);
    00231       if (ReverseDiagDir(exitdir) != m_exitdir) {
    00232         m_err = EC_NO_WAY;
    00233         return false;
    00234       }
    00235       // don't try to enter other player's depots
    00236       if (GetTileOwner(m_new_tile) != m_veh->owner) {
    00237         m_err = EC_OWNER;
    00238         return false;
    00239       }
    00240     }
    00241     if (IsRailTT() && IsTileDepotType(m_new_tile, TT())) {
    00242       DiagDirection exitdir = GetRailDepotDirection(m_new_tile);
    00243       if (ReverseDiagDir(exitdir) != m_exitdir) {
    00244         m_err = EC_NO_WAY;
    00245         return false;
    00246       }
    00247     }
    00248
    00249     // rail transport is possible only on tiles with the same owner as vehicle
    00250     if (IsRailTT() && GetTileOwner(m_new_tile) != m_veh->owner) {
    00251       // different owner
    00252       m_err = EC_NO_WAY;
    00253       return false;
    00254     }
    00255
    00256     // rail transport is possible only on compatible rail types
    00257     if (IsRailTT()) {
    00258       RailType rail_type = GetTileRailType(m_new_tile);
    00259       if (!HasBit(m_veh->u.rail.compatible_railtypes, rail_type)) {
    00260         // incompatible rail type
    00261         m_err = EC_RAIL_TYPE;
    00262         return false;
    00263       }
    00264     }
    00265
    00266     // tunnel holes and bridge ramps can be entered only from proper direction
    00267     if (!IsWaterTT() && IsTileType(m_new_tile, MP_TUNNELBRIDGE)) {
    00268       if (IsTunnel(m_new_tile)) {
    00269         if (!m_is_tunnel) {
    00270           DiagDirection tunnel_enterdir = GetTunnelBridgeDirection(m_new_tile);
    00271           if (tunnel_enterdir != m_exitdir) {
    00272             m_err = EC_NO_WAY;
    00273             return false;
    00274           }
    00275         }
    00276       } else { // IsBridge(m_new_tile)
    00277         if (!m_is_bridge) {
    00278           DiagDirection ramp_enderdir = GetTunnelBridgeDirection(m_new_tile);
    00279           if (ramp_enderdir != m_exitdir) {
    00280             m_err = EC_NO_WAY;
    00281             return false;
    00282           }
    00283         }
    00284       }
    00285     }
    00286
    00287     // special handling for rail stations - get to the end of platform
    00288     if (IsRailTT() && m_is_station) {
    00289       // entered railway station
    00290       // get platform length
    00291       uint length = GetStationByTile(m_new_tile)->GetPlatformLength(m_new_tile, TrackdirToExitdir(m_old_td));
    00292       // how big step we must do to get to the last platform tile;
    00293       m_tiles_skipped = length - 1;
    00294       // move to the platform end
    00295       TileIndexDiff diff = TileOffsByDiagDir(m_exitdir);
    00296       diff *= m_tiles_skipped;
    00297       m_new_tile = TILE_ADD(m_new_tile, diff);
    00298       return true;
    00299     }
    00300
    00301     return true;
    00302   }
    00303
    00305   FORCEINLINE bool ForcedReverse()
    00306   {
    00307     // rail and road depots cause reversing
    00308     if (!IsWaterTT() && IsTileDepotType(m_old_tile, TT())) {
    00309       DiagDirection exitdir = IsRailTT() ? GetRailDepotDirection(m_old_tile) : GetRoadDepotDirection(m_old_tile);
    00310       if (exitdir != m_exitdir) {
    00311         // reverse
    00312         m_new_tile = m_old_tile;
    00313         m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
    00314         m_exitdir = exitdir;
    00315         m_tiles_skipped = 0;
    00316         m_is_tunnel = m_is_bridge = m_is_station = false;
    00317         return true;
    00318       }
    00319     }
    00320
    00321     // single tram bits cause reversing
    00322     if (GetSingleTramBit(m_old_tile) == ReverseDiagDir(m_exitdir)) {
    00323       // reverse
    00324       m_new_tile = m_old_tile;
    00325       m_new_td_bits = TrackdirToTrackdirBits(ReverseTrackdir(m_old_td));
    00326       m_exitdir = ReverseDiagDir(m_exitdir);
    00327       m_tiles_skipped = 0;
    00328       m_is_tunnel = m_is_bridge = m_is_station = false;
    00329       return true;
    00330     }
    00331
    00332     return false;
    00333   }
    00334
    00336   FORCEINLINE bool TryReverse()
    00337   {
    00338     if (IsRoadTT() && !IsTram()) {
    00339       // if we reached the end of road, we can reverse the RV and continue moving
    00340       m_exitdir = ReverseDiagDir(m_exitdir);
    00341       // new tile will be the same as old one
    00342       m_new_tile = m_old_tile;
    00343       // set new trackdir bits to all reachable trackdirs
    00344       QueryNewTileTrackStatus();
    00345       m_new_td_bits &= DiagdirReachesTrackdirs(m_exitdir);
    00346       if (m_new_td_bits != TRACKDIR_BIT_NONE) {
    00347         // we have some trackdirs reachable after reversal
    00348         return true;
    00349       }
    00350     }
    00351     m_err = EC_NO_WAY;
    00352     return false;
    00353   }
    00354
    00355 public:
    00357   int GetSpeedLimit(int *pmin_speed = NULL) const
    00358   {
    00359     int min_speed = 0;
    00360     int max_speed = INT_MAX; // no limit
    00361
    00362     // for now we handle only on-bridge speed limit
    00363     if (!IsWaterTT() && IsBridgeTile(m_old_tile)) {
    00364       int spd = GetBridgeSpec(GetBridgeType(m_old_tile))->speed;
    00365       if (IsRoadTT()) spd *= 2;
    00366       if (max_speed > spd) max_speed = spd;
    00367     }
    00368
    00369     // if min speed was requested, return it
    00370     if (pmin_speed) *pmin_speed = min_speed;
    00371     return max_speed;
    00372   }
    00373 };
    00374
    00375 typedef CFollowTrackT<TRANSPORT_WATER, true > CFollowTrackWater;
    00376 typedef CFollowTrackT<TRANSPORT_ROAD , true > CFollowTrackRoad;
    00377 typedef CFollowTrackT<TRANSPORT_RAIL , true > CFollowTrackRail;
    00378
    00379 typedef CFollowTrackT<TRANSPORT_WATER, false> CFollowTrackWaterNo90;
    00380 typedef CFollowTrackT<TRANSPORT_ROAD , false> CFollowTrackRoadNo90;
    00381 typedef CFollowTrackT<TRANSPORT_RAIL , false> CFollowTrackRailNo90;
    00382
    00383 #endif /* FOLLOW_TRACK_HPP */