npf.cpp

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00001 /* $Id: npf.cpp 15718 2009-03-15 00:32:18Z rubidium $ */
00002 
00005 #include "stdafx.h"
00006 #include "npf.h"
00007 #include "debug.h"
00008 #include "landscape.h"
00009 #include "depot_base.h"
00010 #include "depot_map.h"
00011 #include "network/network.h"
00012 #include "tunnelbridge_map.h"
00013 #include "functions.h"
00014 #include "vehicle_base.h"
00015 #include "tunnelbridge.h"
00016 #include "pbs.h"
00017 #include "settings_type.h"
00018 #include "pathfind.h"
00019 
00020 static AyStar _npf_aystar;
00021 
00022 /* The cost of each trackdir. A diagonal piece is the full NPF_TILE_LENGTH,
00023  * the shorter piece is sqrt(2)/2*NPF_TILE_LENGTH =~ 0.7071
00024  */
00025 #define NPF_STRAIGHT_LENGTH (uint)(NPF_TILE_LENGTH * STRAIGHT_TRACK_LENGTH)
00026 static const uint _trackdir_length[TRACKDIR_END] = {
00027   NPF_TILE_LENGTH, NPF_TILE_LENGTH, NPF_STRAIGHT_LENGTH, NPF_STRAIGHT_LENGTH, NPF_STRAIGHT_LENGTH, NPF_STRAIGHT_LENGTH,
00028   0, 0,
00029   NPF_TILE_LENGTH, NPF_TILE_LENGTH, NPF_STRAIGHT_LENGTH, NPF_STRAIGHT_LENGTH, NPF_STRAIGHT_LENGTH, NPF_STRAIGHT_LENGTH
00030 };
00031 
00038 static uint NPFDistanceTrack(TileIndex t0, TileIndex t1)
00039 {
00040   const uint dx = Delta(TileX(t0), TileX(t1));
00041   const uint dy = Delta(TileY(t0), TileY(t1));
00042 
00043   const uint straightTracks = 2 * min(dx, dy); // The number of straight (not full length) tracks
00044   /* OPTIMISATION:
00045    * Original: diagTracks = max(dx, dy) - min(dx,dy);
00046    * Proof:
00047    * (dx+dy) - straightTracks  == (min + max) - straightTracks = min + max - 2 * min = max - min */
00048   const uint diagTracks = dx + dy - straightTracks; // The number of diagonal (full tile length) tracks.
00049 
00050   /* Don't factor out NPF_TILE_LENGTH below, this will round values and lose
00051    * precision */
00052   return diagTracks * NPF_TILE_LENGTH + straightTracks * NPF_TILE_LENGTH * STRAIGHT_TRACK_LENGTH;
00053 }
00054 
00055 
00056 #if 0
00057 static uint NTPHash(uint key1, uint key2)
00058 {
00059   /* This function uses the old hash, which is fixed on 10 bits (1024 buckets) */
00060   return PATHFIND_HASH_TILE(key1);
00061 }
00062 #endif
00063 
00071 static uint NPFHash(uint key1, uint key2)
00072 {
00073   /* TODO: think of a better hash? */
00074   uint part1 = TileX(key1) & NPF_HASH_HALFMASK;
00075   uint part2 = TileY(key1) & NPF_HASH_HALFMASK;
00076 
00077   assert(IsValidTrackdir((Trackdir)key2));
00078   assert(IsValidTile(key1));
00079   return ((part1 << NPF_HASH_HALFBITS | part2) + (NPF_HASH_SIZE * key2 / TRACKDIR_END)) % NPF_HASH_SIZE;
00080 }
00081 
00082 static int32 NPFCalcZero(AyStar *as, AyStarNode *current, OpenListNode *parent)
00083 {
00084   return 0;
00085 }
00086 
00087 /* Calcs the heuristic to the target station or tile. For train stations, it
00088  * takes into account the direction of approach.
00089  */
00090 static int32 NPFCalcStationOrTileHeuristic(AyStar *as, AyStarNode *current, OpenListNode *parent)
00091 {
00092   NPFFindStationOrTileData *fstd = (NPFFindStationOrTileData*)as->user_target;
00093   NPFFoundTargetData *ftd = (NPFFoundTargetData*)as->user_path;
00094   TileIndex from = current->tile;
00095   TileIndex to = fstd->dest_coords;
00096   uint dist;
00097 
00098   /* for train-stations, we are going to aim for the closest station tile */
00099   if (as->user_data[NPF_TYPE] == TRANSPORT_RAIL && fstd->station_index != INVALID_STATION)
00100     to = CalcClosestStationTile(fstd->station_index, from);
00101 
00102   if (as->user_data[NPF_TYPE] == TRANSPORT_ROAD) {
00103     /* Since roads only have diagonal pieces, we use manhattan distance here */
00104     dist = DistanceManhattan(from, to) * NPF_TILE_LENGTH;
00105   } else {
00106     /* Ships and trains can also go diagonal, so the minimum distance is shorter */
00107     dist = NPFDistanceTrack(from, to);
00108   }
00109 
00110   DEBUG(npf, 4, "Calculating H for: (%d, %d). Result: %d", TileX(current->tile), TileY(current->tile), dist);
00111 
00112   if (dist < ftd->best_bird_dist) {
00113     ftd->best_bird_dist = dist;
00114     ftd->best_trackdir = (Trackdir)current->user_data[NPF_TRACKDIR_CHOICE];
00115   }
00116   return dist;
00117 }
00118 
00119 
00120 /* Fills AyStarNode.user_data[NPF_TRACKDIRCHOICE] with the chosen direction to
00121  * get here, either getting it from the current choice or from the parent's
00122  * choice */
00123 static void NPFFillTrackdirChoice(AyStarNode *current, OpenListNode *parent)
00124 {
00125   if (parent->path.parent == NULL) {
00126     Trackdir trackdir = current->direction;
00127     /* This is a first order decision, so we'd better save the
00128      * direction we chose */
00129     current->user_data[NPF_TRACKDIR_CHOICE] = trackdir;
00130     DEBUG(npf, 6, "Saving trackdir: 0x%X", trackdir);
00131   } else {
00132     /* We've already made the decision, so just save our parent's decision */
00133     current->user_data[NPF_TRACKDIR_CHOICE] = parent->path.node.user_data[NPF_TRACKDIR_CHOICE];
00134   }
00135 }
00136 
00137 /* Will return the cost of the tunnel. If it is an entry, it will return the
00138  * cost of that tile. If the tile is an exit, it will return the tunnel length
00139  * including the exit tile. Requires that this is a Tunnel tile */
00140 static uint NPFTunnelCost(AyStarNode *current)
00141 {
00142   DiagDirection exitdir = TrackdirToExitdir(current->direction);
00143   TileIndex tile = current->tile;
00144   if (GetTunnelBridgeDirection(tile) == ReverseDiagDir(exitdir)) {
00145     /* We just popped out if this tunnel, since were
00146      * facing the tunnel exit */
00147     return NPF_TILE_LENGTH * (GetTunnelBridgeLength(current->tile, GetOtherTunnelEnd(current->tile)) + 1);
00148     /* @todo: Penalty for tunnels? */
00149   } else {
00150     /* We are entering the tunnel, the enter tile is just a
00151      * straight track */
00152     return NPF_TILE_LENGTH;
00153   }
00154 }
00155 
00156 static inline uint NPFBridgeCost(AyStarNode *current)
00157 {
00158   return NPF_TILE_LENGTH * GetTunnelBridgeLength(current->tile, GetOtherBridgeEnd(current->tile));
00159 }
00160 
00161 static uint NPFSlopeCost(AyStarNode *current)
00162 {
00163   TileIndex next = current->tile + TileOffsByDiagDir(TrackdirToExitdir(current->direction));
00164 
00165   /* Get center of tiles */
00166   int x1 = TileX(current->tile) * TILE_SIZE + TILE_SIZE / 2;
00167   int y1 = TileY(current->tile) * TILE_SIZE + TILE_SIZE / 2;
00168   int x2 = TileX(next) * TILE_SIZE + TILE_SIZE / 2;
00169   int y2 = TileY(next) * TILE_SIZE + TILE_SIZE / 2;
00170 
00171   int dx4 = (x2 - x1) / 4;
00172   int dy4 = (y2 - y1) / 4;
00173 
00174   /* Get the height on both sides of the tile edge.
00175    * Avoid testing the height on the tile-center. This will fail for halftile-foundations.
00176    */
00177   int z1 = GetSlopeZ(x1 + dx4, y1 + dy4);
00178   int z2 = GetSlopeZ(x2 - dx4, y2 - dy4);
00179 
00180   if (z2 - z1 > 1) {
00181     /* Slope up */
00182     return _settings_game.pf.npf.npf_rail_slope_penalty;
00183   }
00184   return 0;
00185   /* Should we give a bonus for slope down? Probably not, we
00186    * could just substract that bonus from the penalty, because
00187    * there is only one level of steepness... */
00188 }
00189 
00190 static uint NPFReservedTrackCost(AyStarNode *current)
00191 {
00192   TileIndex tile = current->tile;
00193   TrackBits track = TrackToTrackBits(TrackdirToTrack(current->direction));
00194   TrackBits res = GetReservedTrackbits(tile);
00195 
00196   if (NPFGetFlag(current, NPF_FLAG_3RD_SIGNAL) || ((res & track) == TRACK_BIT_NONE && !TracksOverlap(res | track))) return 0;
00197 
00198   if (IsTileType(tile, MP_TUNNELBRIDGE)) {
00199     DiagDirection exitdir = TrackdirToExitdir(current->direction);
00200     if (GetTunnelBridgeDirection(tile) == ReverseDiagDir(exitdir)) {
00201       return  _settings_game.pf.npf.npf_rail_pbs_cross_penalty * (GetTunnelBridgeLength(tile, GetOtherTunnelBridgeEnd(tile)) + 1);
00202     }
00203   }
00204   return  _settings_game.pf.npf.npf_rail_pbs_cross_penalty;
00205 }
00206 
00211 static void NPFMarkTile(TileIndex tile)
00212 {
00213 #ifndef NO_DEBUG_MESSAGES
00214   if (_debug_npf_level < 1 || _networking) return;
00215   switch (GetTileType(tile)) {
00216     case MP_RAILWAY:
00217       /* DEBUG: mark visited tiles by mowing the grass under them ;-) */
00218       if (!IsRailDepot(tile)) {
00219         SetRailGroundType(tile, RAIL_GROUND_BARREN);
00220         MarkTileDirtyByTile(tile);
00221       }
00222       break;
00223 
00224     case MP_ROAD:
00225       if (!IsRoadDepot(tile)) {
00226         SetRoadside(tile, ROADSIDE_BARREN);
00227         MarkTileDirtyByTile(tile);
00228       }
00229       break;
00230 
00231     default:
00232       break;
00233   }
00234 #endif
00235 }
00236 
00237 static int32 NPFWaterPathCost(AyStar *as, AyStarNode *current, OpenListNode *parent)
00238 {
00239   /* TileIndex tile = current->tile; */
00240   int32 cost = 0;
00241   Trackdir trackdir = current->direction;
00242 
00243   cost = _trackdir_length[trackdir]; // Should be different for diagonal tracks
00244 
00245   if (IsBuoyTile(current->tile) && IsDiagonalTrackdir(trackdir))
00246     cost += _settings_game.pf.npf.npf_buoy_penalty; // A small penalty for going over buoys
00247 
00248   if (current->direction != NextTrackdir((Trackdir)parent->path.node.direction))
00249     cost += _settings_game.pf.npf.npf_water_curve_penalty;
00250 
00251   /* @todo More penalties? */
00252 
00253   return cost;
00254 }
00255 
00256 /* Determine the cost of this node, for road tracks */
00257 static int32 NPFRoadPathCost(AyStar *as, AyStarNode *current, OpenListNode *parent)
00258 {
00259   TileIndex tile = current->tile;
00260   int32 cost = 0;
00261 
00262   /* Determine base length */
00263   switch (GetTileType(tile)) {
00264     case MP_TUNNELBRIDGE:
00265       cost = IsTunnel(tile) ? NPFTunnelCost(current) : NPFBridgeCost(current);
00266       break;
00267 
00268     case MP_ROAD:
00269       cost = NPF_TILE_LENGTH;
00270       /* Increase the cost for level crossings */
00271       if (IsLevelCrossing(tile)) cost += _settings_game.pf.npf.npf_crossing_penalty;
00272       break;
00273 
00274     case MP_STATION:
00275       cost = NPF_TILE_LENGTH;
00276       /* Increase the cost for drive-through road stops */
00277       if (IsDriveThroughStopTile(tile)) cost += _settings_game.pf.npf.npf_road_drive_through_penalty;
00278       break;
00279 
00280     default:
00281       break;
00282   }
00283 
00284   /* Determine extra costs */
00285 
00286   /* Check for slope */
00287   cost += NPFSlopeCost(current);
00288 
00289   /* Check for turns. Road vehicles only really drive diagonal, turns are
00290    * represented by non-diagonal tracks */
00291   if (!IsDiagonalTrackdir(current->direction))
00292     cost += _settings_game.pf.npf.npf_road_curve_penalty;
00293 
00294   NPFMarkTile(tile);
00295   DEBUG(npf, 4, "Calculating G for: (%d, %d). Result: %d", TileX(current->tile), TileY(current->tile), cost);
00296   return cost;
00297 }
00298 
00299 
00300 /* Determine the cost of this node, for railway tracks */
00301 static int32 NPFRailPathCost(AyStar *as, AyStarNode *current, OpenListNode *parent)
00302 {
00303   TileIndex tile = current->tile;
00304   Trackdir trackdir = current->direction;
00305   int32 cost = 0;
00306   /* HACK: We create a OpenListNode manually, so we can call EndNodeCheck */
00307   OpenListNode new_node;
00308 
00309   /* Determine base length */
00310   switch (GetTileType(tile)) {
00311     case MP_TUNNELBRIDGE:
00312       cost = IsTunnel(tile) ? NPFTunnelCost(current) : NPFBridgeCost(current);
00313       break;
00314 
00315     case MP_RAILWAY:
00316       cost = _trackdir_length[trackdir]; // Should be different for diagonal tracks
00317       break;
00318 
00319     case MP_ROAD: // Railway crossing
00320       cost = NPF_TILE_LENGTH;
00321       break;
00322 
00323     case MP_STATION:
00324       /* We give a station tile a penalty. Logically we would only want to give
00325        * station tiles that are not our destination this penalty. This would
00326        * discourage trains to drive through busy stations. But, we can just
00327        * give any station tile a penalty, because every possible route will get
00328        * this penalty exactly once, on its end tile (if it's a station) and it
00329        * will therefore not make a difference. */
00330       cost = NPF_TILE_LENGTH + _settings_game.pf.npf.npf_rail_station_penalty;
00331       break;
00332 
00333     default:
00334       break;
00335   }
00336 
00337   /* Determine extra costs */
00338 
00339   /* Check for signals */
00340   if (IsTileType(tile, MP_RAILWAY)) {
00341     if (HasSignalOnTrackdir(tile, trackdir)) {
00342       /* Ordinary track with signals */
00343       if (GetSignalStateByTrackdir(tile, trackdir) == SIGNAL_STATE_RED) {
00344         /* Signal facing us is red */
00345         if (!NPFGetFlag(current, NPF_FLAG_SEEN_SIGNAL)) {
00346           /* Penalize the first signal we
00347            * encounter, if it is red */
00348 
00349           /* Is this a presignal exit or combo? */
00350           SignalType sigtype = GetSignalType(tile, TrackdirToTrack(trackdir));
00351           if (!IsPbsSignal(sigtype)) {
00352             if (sigtype == SIGTYPE_EXIT || sigtype == SIGTYPE_COMBO) {
00353               /* Penalise exit and combo signals differently (heavier) */
00354               cost += _settings_game.pf.npf.npf_rail_firstred_exit_penalty;
00355             } else {
00356               cost += _settings_game.pf.npf.npf_rail_firstred_penalty;
00357             }
00358           }
00359         }
00360         /* Record the state of this signal */
00361         NPFSetFlag(current, NPF_FLAG_LAST_SIGNAL_RED, true);
00362       } else {
00363         /* Record the state of this signal */
00364         NPFSetFlag(current, NPF_FLAG_LAST_SIGNAL_RED, false);
00365       }
00366       if (NPFGetFlag(current, NPF_FLAG_SEEN_SIGNAL)) {
00367         if (NPFGetFlag(current, NPF_FLAG_2ND_SIGNAL)) {
00368           NPFSetFlag(current, NPF_FLAG_3RD_SIGNAL, true);
00369         } else {
00370           NPFSetFlag(current, NPF_FLAG_2ND_SIGNAL, true);
00371         }
00372       } else {
00373         NPFSetFlag(current, NPF_FLAG_SEEN_SIGNAL, true);
00374       }
00375     }
00376 
00377     if (HasPbsSignalOnTrackdir(tile, ReverseTrackdir(trackdir)) && !NPFGetFlag(current, NPF_FLAG_3RD_SIGNAL)) {
00378       cost += _settings_game.pf.npf.npf_rail_pbs_signal_back_penalty;
00379     }
00380   }
00381 
00382   /* Penalise the tile if it is a target tile and the last signal was
00383    * red */
00384   /* HACK: We create a new_node here so we can call EndNodeCheck. Ugly as hell
00385    * of course... */
00386   new_node.path.node = *current;
00387   if (as->EndNodeCheck(as, &new_node) == AYSTAR_FOUND_END_NODE && NPFGetFlag(current, NPF_FLAG_LAST_SIGNAL_RED))
00388     cost += _settings_game.pf.npf.npf_rail_lastred_penalty;
00389 
00390   /* Check for slope */
00391   cost += NPFSlopeCost(current);
00392 
00393   /* Check for turns */
00394   if (current->direction != NextTrackdir((Trackdir)parent->path.node.direction))
00395     cost += _settings_game.pf.npf.npf_rail_curve_penalty;
00396   /* TODO, with realistic acceleration, also the amount of straight track between
00397    *      curves should be taken into account, as this affects the speed limit. */
00398 
00399   /* Check for reverse in depot */
00400   if (IsRailDepotTile(tile) && as->EndNodeCheck(as, &new_node) != AYSTAR_FOUND_END_NODE) {
00401     /* Penalise any depot tile that is not the last tile in the path. This
00402      * _should_ penalise every occurence of reversing in a depot (and only
00403      * that) */
00404     cost += _settings_game.pf.npf.npf_rail_depot_reverse_penalty;
00405   }
00406 
00407   /* Check for occupied track */
00408   cost += NPFReservedTrackCost(current);
00409 
00410   NPFMarkTile(tile);
00411   DEBUG(npf, 4, "Calculating G for: (%d, %d). Result: %d", TileX(current->tile), TileY(current->tile), cost);
00412   return cost;
00413 }
00414 
00415 /* Will find any depot */
00416 static int32 NPFFindDepot(AyStar *as, OpenListNode *current)
00417 {
00418   /* It's not worth caching the result with NPF_FLAG_IS_TARGET here as below,
00419    * since checking the cache not that much faster than the actual check */
00420   return IsDepotTypeTile(current->path.node.tile, (TransportType)as->user_data[NPF_TYPE]) ?
00421     AYSTAR_FOUND_END_NODE : AYSTAR_DONE;
00422 }
00423 
00425 static int32 NPFFindSafeTile(AyStar *as, OpenListNode *current)
00426 {
00427   const Vehicle *v = ((NPFFindStationOrTileData*)as->user_target)->v;
00428 
00429   return
00430     IsSafeWaitingPosition(v, current->path.node.tile, current->path.node.direction, true, _settings_game.pf.forbid_90_deg) &&
00431     IsWaitingPositionFree(v, current->path.node.tile, current->path.node.direction, _settings_game.pf.forbid_90_deg) ?
00432       AYSTAR_FOUND_END_NODE : AYSTAR_DONE;
00433 }
00434 
00435 /* Will find a station identified using the NPFFindStationOrTileData */
00436 static int32 NPFFindStationOrTile(AyStar *as, OpenListNode *current)
00437 {
00438   NPFFindStationOrTileData *fstd = (NPFFindStationOrTileData*)as->user_target;
00439   AyStarNode *node = &current->path.node;
00440   TileIndex tile = node->tile;
00441 
00442   /* If GetNeighbours said we could get here, we assume the station type
00443    * is correct */
00444   if (
00445     (fstd->station_index == INVALID_STATION && tile == fstd->dest_coords) || // We've found the tile, or
00446     (IsTileType(tile, MP_STATION) && GetStationIndex(tile) == fstd->station_index) // the station
00447   ) {
00448     return AYSTAR_FOUND_END_NODE;
00449   } else {
00450     return AYSTAR_DONE;
00451   }
00452 }
00453 
00461 static const PathNode *FindSafePosition(PathNode *path, const Vehicle *v)
00462 {
00463   /* If there is no signal, reserve the whole path. */
00464   PathNode *sig = path;
00465 
00466   for(; path->parent != NULL; path = path->parent) {
00467     if (IsSafeWaitingPosition(v, path->node.tile, path->node.direction, true, _settings_game.pf.forbid_90_deg)) {
00468       sig = path;
00469     }
00470   }
00471 
00472   return sig;
00473 }
00474 
00478 static void ClearPathReservation(const PathNode *start, const PathNode *end)
00479 {
00480   bool first_run = true;
00481   for (; start != end; start = start->parent) {
00482     if (IsRailwayStationTile(start->node.tile) && first_run) {
00483       SetRailwayStationPlatformReservation(start->node.tile, TrackdirToExitdir(start->node.direction), false);
00484     } else {
00485       UnreserveRailTrack(start->node.tile, TrackdirToTrack(start->node.direction));
00486     }
00487     first_run = false;
00488   }
00489 }
00490 
00497 static void NPFSaveTargetData(AyStar *as, OpenListNode *current)
00498 {
00499   NPFFoundTargetData *ftd = (NPFFoundTargetData*)as->user_path;
00500   ftd->best_trackdir = (Trackdir)current->path.node.user_data[NPF_TRACKDIR_CHOICE];
00501   ftd->best_path_dist = current->g;
00502   ftd->best_bird_dist = 0;
00503   ftd->node = current->path.node;
00504   ftd->res_okay = false;
00505 
00506   if (as->user_target != NULL && ((NPFFindStationOrTileData*)as->user_target)->reserve_path && as->user_data[NPF_TYPE] == TRANSPORT_RAIL) {
00507     /* Path reservation is requested. */
00508     const Vehicle  *v = ((NPFFindStationOrTileData*)as->user_target)->v;
00509 
00510     const PathNode *target = FindSafePosition(&current->path, v);
00511     ftd->node = target->node;
00512 
00513     /* If the target is a station skip to platform end. */
00514     if (IsRailwayStationTile(target->node.tile)) {
00515       DiagDirection dir = TrackdirToExitdir(target->node.direction);
00516       uint len = GetStationByTile(target->node.tile)->GetPlatformLength(target->node.tile, dir);
00517       TileIndex end_tile = TILE_ADD(target->node.tile, (len - 1) * TileOffsByDiagDir(dir));
00518 
00519       /* Update only end tile, trackdir of a station stays the same. */
00520       ftd->node.tile = end_tile;
00521       if (!IsWaitingPositionFree(v, end_tile, target->node.direction, _settings_game.pf.forbid_90_deg)) return;
00522       SetRailwayStationPlatformReservation(target->node.tile, dir, true);
00523       SetRailwayStationReservation(target->node.tile, false);
00524     } else {
00525       if (!IsWaitingPositionFree(v, target->node.tile, target->node.direction, _settings_game.pf.forbid_90_deg)) return;
00526     }
00527 
00528     for (const PathNode *cur = target; cur->parent != NULL; cur = cur->parent) {
00529       if (!TryReserveRailTrack(cur->node.tile, TrackdirToTrack(cur->node.direction))) {
00530         /* Reservation failed, undo. */
00531         ClearPathReservation(target, cur);
00532         return;
00533       }
00534     }
00535 
00536     ftd->res_okay = true;
00537   }
00538 }
00539 
00549 static bool CanEnterTileOwnerCheck(Owner owner, TileIndex tile, DiagDirection enterdir)
00550 {
00551   if (IsTileType(tile, MP_RAILWAY) || // Rail tile (also rail depot)
00552       IsRailwayStationTile(tile) ||   // Rail station tile
00553       IsRoadDepotTile(tile) ||        // Road depot tile
00554       IsStandardRoadStopTile(tile)) { // Road station tile (but not drive-through stops)
00555     return IsTileOwner(tile, owner);  // You need to own these tiles entirely to use them
00556   }
00557 
00558   switch (GetTileType(tile)) {
00559     case MP_ROAD:
00560       /* rail-road crossing : are we looking at the railway part? */
00561       if (IsLevelCrossing(tile) &&
00562           DiagDirToAxis(enterdir) != GetCrossingRoadAxis(tile)) {
00563         return IsTileOwner(tile, owner); // Railway needs owner check, while the street is public
00564       }
00565       break;
00566 
00567     case MP_TUNNELBRIDGE:
00568       if (GetTunnelBridgeTransportType(tile) == TRANSPORT_RAIL) {
00569         return IsTileOwner(tile, owner);
00570       }
00571       break;
00572 
00573     default:
00574       break;
00575   }
00576 
00577   return true; // no need to check
00578 }
00579 
00580 
00584 static DiagDirection GetDepotDirection(TileIndex tile, TransportType type)
00585 {
00586   assert(IsDepotTypeTile(tile, type));
00587 
00588   switch (type) {
00589     case TRANSPORT_RAIL:  return GetRailDepotDirection(tile);
00590     case TRANSPORT_ROAD:  return GetRoadDepotDirection(tile);
00591     case TRANSPORT_WATER: return GetShipDepotDirection(tile);
00592     default: return INVALID_DIAGDIR; // Not reached
00593   }
00594 }
00595 
00597 static DiagDirection GetSingleTramBit(TileIndex tile)
00598 {
00599   if (IsNormalRoadTile(tile)) {
00600     RoadBits rb = GetRoadBits(tile, ROADTYPE_TRAM);
00601     switch (rb) {
00602       case ROAD_NW: return DIAGDIR_NW;
00603       case ROAD_SW: return DIAGDIR_SW;
00604       case ROAD_SE: return DIAGDIR_SE;
00605       case ROAD_NE: return DIAGDIR_NE;
00606       default: break;
00607     }
00608   }
00609   return INVALID_DIAGDIR;
00610 }
00611 
00622 static DiagDirection GetTileSingleEntry(TileIndex tile, TransportType type, uint subtype)
00623 {
00624   if (type != TRANSPORT_WATER && IsDepotTypeTile(tile, type)) return GetDepotDirection(tile, type);
00625 
00626   if (type == TRANSPORT_ROAD) {
00627     if (IsStandardRoadStopTile(tile)) return GetRoadStopDir(tile);
00628     if (HasBit(subtype, ROADTYPE_TRAM)) return GetSingleTramBit(tile);
00629   }
00630 
00631   return INVALID_DIAGDIR;
00632 }
00633 
00643 static inline bool ForceReverse(TileIndex tile, DiagDirection dir, TransportType type, uint subtype)
00644 {
00645   DiagDirection single_entry = GetTileSingleEntry(tile, type, subtype);
00646   return single_entry != INVALID_DIAGDIR && single_entry != dir;
00647 }
00648 
00660 static bool CanEnterTile(TileIndex tile, DiagDirection dir, TransportType type, uint subtype, RailTypes railtypes, Owner owner)
00661 {
00662   /* Check tunnel entries and bridge ramps */
00663   if (IsTileType(tile, MP_TUNNELBRIDGE) && GetTunnelBridgeDirection(tile) != dir) return false;
00664 
00665   /* Test ownership */
00666   if (!CanEnterTileOwnerCheck(owner, tile, dir)) return false;
00667 
00668   /* check correct rail type (mono, maglev, etc) */
00669   if (type == TRANSPORT_RAIL) {
00670     RailType rail_type = GetTileRailType(tile);
00671     if (!HasBit(railtypes, rail_type)) return false;
00672   }
00673 
00674   /* Depots, standard roadstops and single tram bits can only be entered from one direction */
00675   DiagDirection single_entry = GetTileSingleEntry(tile, type, subtype);
00676   if (single_entry != INVALID_DIAGDIR && single_entry != ReverseDiagDir(dir)) return false;
00677 
00678   return true;
00679 }
00680 
00692 static TrackdirBits GetDriveableTrackdirBits(TileIndex dst_tile, Trackdir src_trackdir, TransportType type, uint subtype)
00693 {
00694   TrackdirBits trackdirbits = TrackStatusToTrackdirBits(GetTileTrackStatus(dst_tile, type, subtype));
00695 
00696   if (trackdirbits == 0 && type == TRANSPORT_ROAD && HasBit(subtype, ROADTYPE_TRAM)) {
00697     /* GetTileTrackStatus() returns 0 for single tram bits.
00698      * As we cannot change it there (easily) without breaking something, change it here */
00699     switch (GetSingleTramBit(dst_tile)) {
00700       case DIAGDIR_NE:
00701       case DIAGDIR_SW:
00702         trackdirbits = TRACKDIR_BIT_X_NE | TRACKDIR_BIT_X_SW;
00703         break;
00704 
00705       case DIAGDIR_NW:
00706       case DIAGDIR_SE:
00707         trackdirbits = TRACKDIR_BIT_Y_NW | TRACKDIR_BIT_Y_SE;
00708         break;
00709 
00710       default: break;
00711     }
00712   }
00713 
00714   DEBUG(npf, 4, "Next node: (%d, %d) [%d], possible trackdirs: 0x%X", TileX(dst_tile), TileY(dst_tile), dst_tile, trackdirbits);
00715 
00716   /* Select only trackdirs we can reach from our current trackdir */
00717   trackdirbits &= TrackdirReachesTrackdirs(src_trackdir);
00718 
00719   /* Filter out trackdirs that would make 90 deg turns for trains */
00720   if (_settings_game.pf.forbid_90_deg && (type == TRANSPORT_RAIL || type == TRANSPORT_WATER)) trackdirbits &= ~TrackdirCrossesTrackdirs(src_trackdir);
00721 
00722   DEBUG(npf, 6, "After filtering: (%d, %d), possible trackdirs: 0x%X", TileX(dst_tile), TileY(dst_tile), trackdirbits);
00723 
00724   return trackdirbits;
00725 }
00726 
00727 
00728 /* Will just follow the results of GetTileTrackStatus concerning where we can
00729  * go and where not. Uses AyStar.user_data[NPF_TYPE] as the transport type and
00730  * an argument to GetTileTrackStatus. Will skip tunnels, meaning that the
00731  * entry and exit are neighbours. Will fill
00732  * AyStarNode.user_data[NPF_TRACKDIR_CHOICE] with an appropriate value, and
00733  * copy AyStarNode.user_data[NPF_NODE_FLAGS] from the parent */
00734 static void NPFFollowTrack(AyStar *aystar, OpenListNode *current)
00735 {
00736   /* We leave src_tile on track src_trackdir in direction src_exitdir */
00737   Trackdir src_trackdir = current->path.node.direction;
00738   TileIndex src_tile = current->path.node.tile;
00739   DiagDirection src_exitdir = TrackdirToExitdir(src_trackdir);
00740 
00741   /* Is src_tile valid, and can be used?
00742    * When choosing track on a junction src_tile is the tile neighboured to the junction wrt. exitdir.
00743    * But we must not check the validity of this move, as src_tile is totally unrelated to the move, if a roadvehicle reversed on a junction. */
00744   bool ignore_src_tile = (current->path.parent == NULL && NPFGetFlag(&current->path.node, NPF_FLAG_IGNORE_START_TILE));
00745 
00746   /* Information about the vehicle: TransportType (road/rail/water) and SubType (compatible rail/road types) */
00747   TransportType type = (TransportType)aystar->user_data[NPF_TYPE];
00748   uint subtype = aystar->user_data[NPF_SUB_TYPE];
00749 
00750   /* Initialize to 0, so we can jump out (return) somewhere an have no neighbours */
00751   aystar->num_neighbours = 0;
00752   DEBUG(npf, 4, "Expanding: (%d, %d, %d) [%d]", TileX(src_tile), TileY(src_tile), src_trackdir, src_tile);
00753 
00754   /* We want to determine the tile we arrive, and which choices we have there */
00755   TileIndex dst_tile;
00756   TrackdirBits trackdirbits;
00757 
00758   /* Find dest tile */
00759   if (ignore_src_tile) {
00760     /* Do not perform any checks that involve src_tile */
00761     dst_tile = src_tile + TileOffsByDiagDir(src_exitdir);
00762     trackdirbits = GetDriveableTrackdirBits(dst_tile, src_trackdir, type, subtype);
00763   } else if (IsTileType(src_tile, MP_TUNNELBRIDGE) && GetTunnelBridgeDirection(src_tile) == src_exitdir) {
00764     /* We drive through the wormhole and arrive on the other side */
00765     dst_tile = GetOtherTunnelBridgeEnd(src_tile);
00766     trackdirbits = TrackdirToTrackdirBits(src_trackdir);
00767   } else if (ForceReverse(src_tile, src_exitdir, type, subtype)) {
00768     /* We can only reverse on this tile */
00769     dst_tile = src_tile;
00770     src_trackdir = ReverseTrackdir(src_trackdir);
00771     trackdirbits = TrackdirToTrackdirBits(src_trackdir);
00772   } else {
00773     /* We leave src_tile in src_exitdir and reach dst_tile */
00774     dst_tile = AddTileIndexDiffCWrap(src_tile, TileIndexDiffCByDiagDir(src_exitdir));
00775 
00776     if (dst_tile != INVALID_TILE && !CanEnterTile(dst_tile, src_exitdir, type, subtype, (RailTypes)aystar->user_data[NPF_RAILTYPES], (Owner)aystar->user_data[NPF_OWNER])) dst_tile = INVALID_TILE;
00777 
00778     if (dst_tile == INVALID_TILE) {
00779       /* We cannot enter the next tile. Road vehicles can reverse, others reach dead end */
00780       if (type != TRANSPORT_ROAD || HasBit(subtype, ROADTYPE_TRAM)) return;
00781 
00782       dst_tile = src_tile;
00783       src_trackdir = ReverseTrackdir(src_trackdir);
00784     }
00785 
00786     trackdirbits = GetDriveableTrackdirBits(dst_tile, src_trackdir, type, subtype);
00787 
00788     if (trackdirbits == 0) {
00789       /* We cannot enter the next tile. Road vehicles can reverse, others reach dead end */
00790       if (type != TRANSPORT_ROAD || HasBit(subtype, ROADTYPE_TRAM)) return;
00791 
00792       dst_tile = src_tile;
00793       src_trackdir = ReverseTrackdir(src_trackdir);
00794 
00795       trackdirbits = GetDriveableTrackdirBits(dst_tile, src_trackdir, type, subtype);
00796     }
00797   }
00798 
00799   if (NPFGetFlag(&current->path.node, NPF_FLAG_IGNORE_RESERVED)) {
00800     /* Mask out any reserved tracks. */
00801     TrackBits reserved = GetReservedTrackbits(dst_tile);
00802     trackdirbits &= ~TrackBitsToTrackdirBits(reserved);
00803 
00804     uint bits = TrackdirBitsToTrackBits(trackdirbits);
00805     int i;
00806     FOR_EACH_SET_BIT(i, bits) {
00807       if (TracksOverlap(reserved | TrackToTrackBits((Track)i))) trackdirbits &= ~TrackToTrackdirBits((Track)i);
00808     }
00809   }
00810 
00811   /* Enumerate possible track */
00812   uint i = 0;
00813   while (trackdirbits != 0) {
00814     Trackdir dst_trackdir = RemoveFirstTrackdir(&trackdirbits);
00815     DEBUG(npf, 5, "Expanded into trackdir: %d, remaining trackdirs: 0x%X", dst_trackdir, trackdirbits);
00816 
00817     /* Tile with signals? */
00818     if (IsTileType(dst_tile, MP_RAILWAY) && GetRailTileType(dst_tile) == RAIL_TILE_SIGNALS) {
00819       if (HasSignalOnTrackdir(dst_tile, ReverseTrackdir(dst_trackdir)) && !HasSignalOnTrackdir(dst_tile, dst_trackdir) && IsOnewaySignal(dst_tile, TrackdirToTrack(dst_trackdir)))
00820         /* If there's a one-way signal not pointing towards us, stop going in this direction. */
00821         break;
00822     }
00823     {
00824       /* We've found ourselves a neighbour :-) */
00825       AyStarNode *neighbour = &aystar->neighbours[i];
00826       neighbour->tile = dst_tile;
00827       neighbour->direction = dst_trackdir;
00828       /* Save user data */
00829       neighbour->user_data[NPF_NODE_FLAGS] = current->path.node.user_data[NPF_NODE_FLAGS];
00830       NPFFillTrackdirChoice(neighbour, current);
00831     }
00832     i++;
00833   }
00834   aystar->num_neighbours = i;
00835 }
00836 
00837 /*
00838  * Plan a route to the specified target (which is checked by target_proc),
00839  * from start1 and if not NULL, from start2 as well. The type of transport we
00840  * are checking is in type. reverse_penalty is applied to all routes that
00841  * originate from the second start node.
00842  * When we are looking for one specific target (optionally multiple tiles), we
00843  * should use a good heuristic to perform aystar search. When we search for
00844  * multiple targets that are spread around, we should perform a breadth first
00845  * search by specifiying CalcZero as our heuristic.
00846  */
00847 static NPFFoundTargetData NPFRouteInternal(AyStarNode *start1, bool ignore_start_tile1, AyStarNode *start2, bool ignore_start_tile2, NPFFindStationOrTileData *target, AyStar_EndNodeCheck target_proc, AyStar_CalculateH heuristic_proc, TransportType type, uint sub_type, Owner owner, RailTypes railtypes, uint reverse_penalty)
00848 {
00849   int r;
00850   NPFFoundTargetData result;
00851 
00852   /* Initialize procs */
00853   _npf_aystar.CalculateH = heuristic_proc;
00854   _npf_aystar.EndNodeCheck = target_proc;
00855   _npf_aystar.FoundEndNode = NPFSaveTargetData;
00856   _npf_aystar.GetNeighbours = NPFFollowTrack;
00857   switch (type) {
00858     default: NOT_REACHED();
00859     case TRANSPORT_RAIL:  _npf_aystar.CalculateG = NPFRailPathCost;  break;
00860     case TRANSPORT_ROAD:  _npf_aystar.CalculateG = NPFRoadPathCost;  break;
00861     case TRANSPORT_WATER: _npf_aystar.CalculateG = NPFWaterPathCost; break;
00862   }
00863 
00864   /* Initialize Start Node(s) */
00865   start1->user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
00866   start1->user_data[NPF_NODE_FLAGS] = 0;
00867   NPFSetFlag(start1, NPF_FLAG_IGNORE_START_TILE, ignore_start_tile1);
00868   _npf_aystar.addstart(&_npf_aystar, start1, 0);
00869   if (start2) {
00870     start2->user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
00871     start2->user_data[NPF_NODE_FLAGS] = 0;
00872     NPFSetFlag(start2, NPF_FLAG_IGNORE_START_TILE, ignore_start_tile2);
00873     NPFSetFlag(start2, NPF_FLAG_REVERSE, true);
00874     _npf_aystar.addstart(&_npf_aystar, start2, reverse_penalty);
00875   }
00876 
00877   /* Initialize result */
00878   result.best_bird_dist = UINT_MAX;
00879   result.best_path_dist = UINT_MAX;
00880   result.best_trackdir  = INVALID_TRACKDIR;
00881   result.node.tile      = INVALID_TILE;
00882   result.res_okay       = false;
00883   _npf_aystar.user_path = &result;
00884 
00885   /* Initialize target */
00886   _npf_aystar.user_target = target;
00887 
00888   /* Initialize user_data */
00889   _npf_aystar.user_data[NPF_TYPE] = type;
00890   _npf_aystar.user_data[NPF_SUB_TYPE] = sub_type;
00891   _npf_aystar.user_data[NPF_OWNER] = owner;
00892   _npf_aystar.user_data[NPF_RAILTYPES] = railtypes;
00893 
00894   /* GO! */
00895   r = AyStarMain_Main(&_npf_aystar);
00896   assert(r != AYSTAR_STILL_BUSY);
00897 
00898   if (result.best_bird_dist != 0) {
00899     if (target != NULL) {
00900       DEBUG(npf, 1, "Could not find route to tile 0x%X from 0x%X.", target->dest_coords, start1->tile);
00901     } else {
00902       /* Assumption: target == NULL, so we are looking for a depot */
00903       DEBUG(npf, 1, "Could not find route to a depot from tile 0x%X.", start1->tile);
00904     }
00905 
00906   }
00907   return result;
00908 }
00909 
00910 NPFFoundTargetData NPFRouteToStationOrTileTwoWay(TileIndex tile1, Trackdir trackdir1, bool ignore_start_tile1, TileIndex tile2, Trackdir trackdir2, bool ignore_start_tile2, NPFFindStationOrTileData *target, TransportType type, uint sub_type, Owner owner, RailTypes railtypes)
00911 {
00912   AyStarNode start1;
00913   AyStarNode start2;
00914 
00915   start1.tile = tile1;
00916   start2.tile = tile2;
00917   /* We set this in case the target is also the start tile, we will just
00918    * return a not found then */
00919   start1.user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
00920   start1.direction = trackdir1;
00921   start2.direction = trackdir2;
00922   start2.user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
00923 
00924   return NPFRouteInternal(&start1, ignore_start_tile1, (IsValidTile(tile2) ? &start2 : NULL), ignore_start_tile2, target, NPFFindStationOrTile, NPFCalcStationOrTileHeuristic, type, sub_type, owner, railtypes, 0);
00925 }
00926 
00927 NPFFoundTargetData NPFRouteToStationOrTile(TileIndex tile, Trackdir trackdir, bool ignore_start_tile, NPFFindStationOrTileData *target, TransportType type, uint sub_type, Owner owner, RailTypes railtypes)
00928 {
00929   return NPFRouteToStationOrTileTwoWay(tile, trackdir, ignore_start_tile, INVALID_TILE, INVALID_TRACKDIR, false, target, type, sub_type, owner, railtypes);
00930 }
00931 
00932 NPFFoundTargetData NPFRouteToDepotBreadthFirstTwoWay(TileIndex tile1, Trackdir trackdir1, bool ignore_start_tile1, TileIndex tile2, Trackdir trackdir2, bool ignore_start_tile2, TransportType type, uint sub_type, Owner owner, RailTypes railtypes, uint reverse_penalty)
00933 {
00934   AyStarNode start1;
00935   AyStarNode start2;
00936 
00937   start1.tile = tile1;
00938   start2.tile = tile2;
00939   /* We set this in case the target is also the start tile, we will just
00940    * return a not found then */
00941   start1.user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
00942   start1.direction = trackdir1;
00943   start2.direction = trackdir2;
00944   start2.user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
00945 
00946   /* perform a breadth first search. Target is NULL,
00947    * since we are just looking for any depot...*/
00948   return NPFRouteInternal(&start1, ignore_start_tile1, (IsValidTile(tile2) ? &start2 : NULL), ignore_start_tile2, NULL, NPFFindDepot, NPFCalcZero, type, sub_type, owner, railtypes, reverse_penalty);
00949 }
00950 
00951 NPFFoundTargetData NPFRouteToDepotBreadthFirst(TileIndex tile, Trackdir trackdir, bool ignore_start_tile, TransportType type, uint sub_type, Owner owner, RailTypes railtypes)
00952 {
00953   return NPFRouteToDepotBreadthFirstTwoWay(tile, trackdir, ignore_start_tile, INVALID_TILE, INVALID_TRACKDIR, false, type, sub_type, owner, railtypes, 0);
00954 }
00955 
00956 NPFFoundTargetData NPFRouteToDepotTrialError(TileIndex tile, Trackdir trackdir, bool ignore_start_tile, TransportType type, uint sub_type, Owner owner, RailTypes railtypes)
00957 {
00958   /* Okay, what we're gonna do. First, we look at all depots, calculate
00959    * the manhatten distance to get to each depot. We then sort them by
00960    * distance. We start by trying to plan a route to the closest, then
00961    * the next closest, etc. We stop when the best route we have found so
00962    * far, is shorter than the manhattan distance. This will obviously
00963    * always find the closest depot. It will probably be most efficient
00964    * for ships, since the heuristic will not be to far off then. I hope.
00965    */
00966   Queue depots;
00967   int r;
00968   NPFFoundTargetData best_result = {UINT_MAX, UINT_MAX, INVALID_TRACKDIR, {INVALID_TILE, INVALID_TRACKDIR, {0, 0}}, false};
00969   NPFFoundTargetData result;
00970   NPFFindStationOrTileData target;
00971   AyStarNode start;
00972   Depot *current;
00973   Depot *depot;
00974 
00975   init_InsSort(&depots);
00976   /* Okay, let's find all depots that we can use first */
00977   FOR_ALL_DEPOTS(depot) {
00978     /* Check if this is really a valid depot, it is of the needed type and
00979      * owner */
00980     if (IsDepotTypeTile(depot->xy, type) && IsTileOwner(depot->xy, owner))
00981       /* If so, let's add it to the queue, sorted by distance */
00982       depots.push(&depots, depot, DistanceManhattan(tile, depot->xy));
00983   }
00984 
00985   /* Now, let's initialise the aystar */
00986 
00987   /* Initialize procs */
00988   _npf_aystar.CalculateH = NPFCalcStationOrTileHeuristic;
00989   _npf_aystar.EndNodeCheck = NPFFindStationOrTile;
00990   _npf_aystar.FoundEndNode = NPFSaveTargetData;
00991   _npf_aystar.GetNeighbours = NPFFollowTrack;
00992   switch (type) {
00993     default: NOT_REACHED();
00994     case TRANSPORT_RAIL:  _npf_aystar.CalculateG = NPFRailPathCost;  break;
00995     case TRANSPORT_ROAD:  _npf_aystar.CalculateG = NPFRoadPathCost;  break;
00996     case TRANSPORT_WATER: _npf_aystar.CalculateG = NPFWaterPathCost; break;
00997   }
00998 
00999   /* Initialize target */
01000   target.station_index = INVALID_STATION; // We will initialize dest_coords inside the loop below
01001   _npf_aystar.user_target = &target;
01002 
01003   /* Initialize user_data */
01004   _npf_aystar.user_data[NPF_TYPE] = type;
01005   _npf_aystar.user_data[NPF_SUB_TYPE] = sub_type;
01006   _npf_aystar.user_data[NPF_OWNER] = owner;
01007 
01008   /* Initialize Start Node */
01009   start.tile = tile;
01010   start.direction = trackdir; // We will initialize user_data inside the loop below
01011 
01012   /* Initialize Result */
01013   _npf_aystar.user_path = &result;
01014   best_result.best_path_dist = UINT_MAX;
01015   best_result.best_bird_dist = UINT_MAX;
01016 
01017   /* Just iterate the depots in order of increasing distance */
01018   while ((current = (Depot*)depots.pop(&depots))) {
01019     /* Check to see if we already have a path shorter than this
01020      * depot's manhattan distance. HACK: We call DistanceManhattan
01021      * again, we should probably modify the queue to give us that
01022      * value... */
01023     if ( DistanceManhattan(tile, current->xy * NPF_TILE_LENGTH) > best_result.best_path_dist)
01024       break;
01025 
01026     /* Initialize Start Node
01027      * We set this in case the target is also the start tile, we will just
01028      * return a not found then */
01029     start.user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
01030     start.user_data[NPF_NODE_FLAGS] = 0;
01031     NPFSetFlag(&start, NPF_FLAG_IGNORE_START_TILE, ignore_start_tile);
01032     _npf_aystar.addstart(&_npf_aystar, &start, 0);
01033 
01034     /* Initialize result */
01035     result.best_bird_dist = UINT_MAX;
01036     result.best_path_dist = UINT_MAX;
01037     result.best_trackdir = INVALID_TRACKDIR;
01038 
01039     /* Initialize target */
01040     target.dest_coords = current->xy;
01041 
01042     /* GO! */
01043     r = AyStarMain_Main(&_npf_aystar);
01044     assert(r != AYSTAR_STILL_BUSY);
01045 
01046     /* This depot is closer */
01047     if (result.best_path_dist < best_result.best_path_dist)
01048       best_result = result;
01049   }
01050   if (result.best_bird_dist != 0) {
01051     DEBUG(npf, 1, "Could not find route to any depot from tile 0x%X.", tile);
01052   }
01053   return best_result;
01054 }
01055 
01056 NPFFoundTargetData NPFRouteToSafeTile(const Vehicle *v, TileIndex tile, Trackdir trackdir, bool override_railtype)
01057 {
01058   assert(v->type == VEH_TRAIN);
01059 
01060   NPFFindStationOrTileData fstd;
01061   fstd.v = v;
01062   fstd.reserve_path = true;
01063 
01064   AyStarNode start1;
01065   start1.tile = tile;
01066   /* We set this in case the target is also the start tile, we will just
01067    * return a not found then */
01068   start1.user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
01069   start1.direction = trackdir;
01070   NPFSetFlag(&start1, NPF_FLAG_IGNORE_RESERVED, true);
01071 
01072   RailTypes railtypes = v->u.rail.compatible_railtypes;
01073   if (override_railtype) railtypes |= GetRailTypeInfo(v->u.rail.railtype)->compatible_railtypes;
01074 
01075   /* perform a breadth first search. Target is NULL,
01076    * since we are just looking for any safe tile...*/
01077   return NPFRouteInternal(&start1, true, NULL, false, &fstd, NPFFindSafeTile, NPFCalcZero, TRANSPORT_RAIL, 0, v->owner, railtypes, 0);
01078 }
01079 
01080 void InitializeNPF()
01081 {
01082   static bool first_init = true;
01083   if (first_init) {
01084     first_init = false;
01085     init_AyStar(&_npf_aystar, NPFHash, NPF_HASH_SIZE);
01086   } else {
01087     AyStarMain_Clear(&_npf_aystar);
01088   }
01089   _npf_aystar.loops_per_tick = 0;
01090   _npf_aystar.max_path_cost = 0;
01091   //_npf_aystar.max_search_nodes = 0;
01092   /* We will limit the number of nodes for now, until we have a better
01093    * solution to really fix performance */
01094   _npf_aystar.max_search_nodes = _settings_game.pf.npf.npf_max_search_nodes;
01095 }
01096 
01097 void NPFFillWithOrderData(NPFFindStationOrTileData *fstd, Vehicle *v, bool reserve_path)
01098 {
01099   /* Ships don't really reach their stations, but the tile in front. So don't
01100    * save the station id for ships. For roadvehs we don't store it either,
01101    * because multistop depends on vehicles actually reaching the exact
01102    * dest_tile, not just any stop of that station.
01103    * So only for train orders to stations we fill fstd->station_index, for all
01104    * others only dest_coords */
01105   if (v->current_order.IsType(OT_GOTO_STATION) && v->type == VEH_TRAIN) {
01106     fstd->station_index = v->current_order.GetDestination();
01107     /* Let's take the closest tile of the station as our target for trains */
01108     fstd->dest_coords = CalcClosestStationTile(fstd->station_index, v->tile);
01109   } else {
01110     fstd->dest_coords = v->dest_tile;
01111     fstd->station_index = INVALID_STATION;
01112   }
01113   fstd->reserve_path = reserve_path;
01114   fstd->v = v;
01115 }

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