npf.cpp

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00001 /* $Id: npf.cpp 18535 2009-12-19 15:30:24Z 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 #include "../../stdafx.h"
00013 #include "../../debug.h"
00014 #include "../../landscape.h"
00015 #include "../../depot_base.h"
00016 #include "../../network/network.h"
00017 #include "../../tunnelbridge_map.h"
00018 #include "../../functions.h"
00019 #include "../../tunnelbridge.h"
00020 #include "../../pbs.h"
00021 #include "../../roadveh.h"
00022 #include "../../ship.h"
00023 #include "../../train.h"
00024 #include "../../roadstop_base.h"
00025 #include "../pathfinder_func.h"
00026 #include "../pathfinder_type.h"
00027 #include "../follow_track.hpp"
00028 #include "aystar.h"
00029 
00030 enum {
00031   NPF_HASH_BITS = 12, 
00032   /* Do no change below values */
00033   NPF_HASH_SIZE = 1 << NPF_HASH_BITS,
00034   NPF_HASH_HALFBITS = NPF_HASH_BITS / 2,
00035   NPF_HASH_HALFMASK = (1 << NPF_HASH_HALFBITS) - 1
00036 };
00037 
00038 /* Meant to be stored in AyStar.targetdata */
00039 struct NPFFindStationOrTileData {
00040   TileIndex dest_coords;    
00041   StationID station_index;  
00042   bool reserve_path;        
00043   StationType station_type; 
00044   bool not_articulated;     
00045   const Vehicle *v;         
00046 };
00047 
00048 /* Indices into AyStar.userdata[] */
00049 enum {
00050   NPF_TYPE = 0,  
00051   NPF_SUB_TYPE,  
00052   NPF_OWNER,     
00053   NPF_RAILTYPES, 
00054 };
00055 
00056 /* Indices into AyStarNode.userdata[] */
00057 enum {
00058   NPF_TRACKDIR_CHOICE = 0, 
00059   NPF_NODE_FLAGS,
00060 };
00061 
00062 /* Flags for AyStarNode.userdata[NPF_NODE_FLAGS]. Use NPFSetFlag() and NPFGetFlag() to use them. */
00063 enum NPFNodeFlag {
00064   NPF_FLAG_SEEN_SIGNAL,       
00065   NPF_FLAG_2ND_SIGNAL,        
00066   NPF_FLAG_3RD_SIGNAL,        
00067   NPF_FLAG_REVERSE,           
00068   NPF_FLAG_LAST_SIGNAL_RED,   
00069   NPF_FLAG_LAST_SIGNAL_BLOCK, 
00070   NPF_FLAG_IGNORE_START_TILE, 
00071   NPF_FLAG_TARGET_RESERVED,   
00072   NPF_FLAG_IGNORE_RESERVED,   
00073 };
00074 
00075 /* Meant to be stored in AyStar.userpath */
00076 struct NPFFoundTargetData {
00077   uint best_bird_dist;    
00078   uint best_path_dist;    
00079   Trackdir best_trackdir; 
00080   AyStarNode node;        
00081   bool res_okay;          
00082 };
00083 
00084 static AyStar _npf_aystar;
00085 
00086 /* The cost of each trackdir. A diagonal piece is the full NPF_TILE_LENGTH,
00087  * the shorter piece is sqrt(2)/2*NPF_TILE_LENGTH =~ 0.7071
00088  */
00089 #define NPF_STRAIGHT_LENGTH (uint)(NPF_TILE_LENGTH * STRAIGHT_TRACK_LENGTH)
00090 static const uint _trackdir_length[TRACKDIR_END] = {
00091   NPF_TILE_LENGTH, NPF_TILE_LENGTH, NPF_STRAIGHT_LENGTH, NPF_STRAIGHT_LENGTH, NPF_STRAIGHT_LENGTH, NPF_STRAIGHT_LENGTH,
00092   0, 0,
00093   NPF_TILE_LENGTH, NPF_TILE_LENGTH, NPF_STRAIGHT_LENGTH, NPF_STRAIGHT_LENGTH, NPF_STRAIGHT_LENGTH, NPF_STRAIGHT_LENGTH
00094 };
00095 
00099 static inline bool NPFGetFlag(const AyStarNode *node, NPFNodeFlag flag)
00100 {
00101   return HasBit(node->user_data[NPF_NODE_FLAGS], flag);
00102 }
00103 
00107 static inline void NPFSetFlag(AyStarNode *node, NPFNodeFlag flag, bool value)
00108 {
00109   SB(node->user_data[NPF_NODE_FLAGS], flag, 1, value);
00110 }
00111 
00118 static uint NPFDistanceTrack(TileIndex t0, TileIndex t1)
00119 {
00120   const uint dx = Delta(TileX(t0), TileX(t1));
00121   const uint dy = Delta(TileY(t0), TileY(t1));
00122 
00123   const uint straightTracks = 2 * min(dx, dy); // The number of straight (not full length) tracks
00124   /* OPTIMISATION:
00125    * Original: diagTracks = max(dx, dy) - min(dx,dy);
00126    * Proof:
00127    * (dx+dy) - straightTracks  == (min + max) - straightTracks = min + max - 2 * min = max - min */
00128   const uint diagTracks = dx + dy - straightTracks; // The number of diagonal (full tile length) tracks.
00129 
00130   /* Don't factor out NPF_TILE_LENGTH below, this will round values and lose
00131    * precision */
00132   return diagTracks * NPF_TILE_LENGTH + straightTracks * NPF_TILE_LENGTH * STRAIGHT_TRACK_LENGTH;
00133 }
00134 
00135 
00136 #if 0
00137 static uint NTPHash(uint key1, uint key2)
00138 {
00139   /* This function uses the old hash, which is fixed on 10 bits (1024 buckets) */
00140   return PATHFIND_HASH_TILE(key1);
00141 }
00142 #endif
00143 
00151 static uint NPFHash(uint key1, uint key2)
00152 {
00153   /* TODO: think of a better hash? */
00154   uint part1 = TileX(key1) & NPF_HASH_HALFMASK;
00155   uint part2 = TileY(key1) & NPF_HASH_HALFMASK;
00156 
00157   assert(IsValidTrackdir((Trackdir)key2));
00158   assert(IsValidTile(key1));
00159   return ((part1 << NPF_HASH_HALFBITS | part2) + (NPF_HASH_SIZE * key2 / TRACKDIR_END)) % NPF_HASH_SIZE;
00160 }
00161 
00162 static int32 NPFCalcZero(AyStar *as, AyStarNode *current, OpenListNode *parent)
00163 {
00164   return 0;
00165 }
00166 
00167 /* Calcs the heuristic to the target station or tile. For train stations, it
00168  * takes into account the direction of approach.
00169  */
00170 static int32 NPFCalcStationOrTileHeuristic(AyStar *as, AyStarNode *current, OpenListNode *parent)
00171 {
00172   NPFFindStationOrTileData *fstd = (NPFFindStationOrTileData*)as->user_target;
00173   NPFFoundTargetData *ftd = (NPFFoundTargetData*)as->user_path;
00174   TileIndex from = current->tile;
00175   TileIndex to = fstd->dest_coords;
00176   uint dist;
00177 
00178   /* for train-stations, we are going to aim for the closest station tile */
00179   if (as->user_data[NPF_TYPE] != TRANSPORT_WATER && fstd->station_index != INVALID_STATION)
00180     to = CalcClosestStationTile(fstd->station_index, from, fstd->station_type);
00181 
00182   if (as->user_data[NPF_TYPE] == TRANSPORT_ROAD) {
00183     /* Since roads only have diagonal pieces, we use manhattan distance here */
00184     dist = DistanceManhattan(from, to) * NPF_TILE_LENGTH;
00185   } else {
00186     /* Ships and trains can also go diagonal, so the minimum distance is shorter */
00187     dist = NPFDistanceTrack(from, to);
00188   }
00189 
00190   DEBUG(npf, 4, "Calculating H for: (%d, %d). Result: %d", TileX(current->tile), TileY(current->tile), dist);
00191 
00192   if (dist < ftd->best_bird_dist) {
00193     ftd->best_bird_dist = dist;
00194     ftd->best_trackdir = (Trackdir)current->user_data[NPF_TRACKDIR_CHOICE];
00195   }
00196   return dist;
00197 }
00198 
00199 
00200 /* Fills AyStarNode.user_data[NPF_TRACKDIRCHOICE] with the chosen direction to
00201  * get here, either getting it from the current choice or from the parent's
00202  * choice */
00203 static void NPFFillTrackdirChoice(AyStarNode *current, OpenListNode *parent)
00204 {
00205   if (parent->path.parent == NULL) {
00206     Trackdir trackdir = current->direction;
00207     /* This is a first order decision, so we'd better save the
00208      * direction we chose */
00209     current->user_data[NPF_TRACKDIR_CHOICE] = trackdir;
00210     DEBUG(npf, 6, "Saving trackdir: 0x%X", trackdir);
00211   } else {
00212     /* We've already made the decision, so just save our parent's decision */
00213     current->user_data[NPF_TRACKDIR_CHOICE] = parent->path.node.user_data[NPF_TRACKDIR_CHOICE];
00214   }
00215 }
00216 
00217 /* Will return the cost of the tunnel. If it is an entry, it will return the
00218  * cost of that tile. If the tile is an exit, it will return the tunnel length
00219  * including the exit tile. Requires that this is a Tunnel tile */
00220 static uint NPFTunnelCost(AyStarNode *current)
00221 {
00222   DiagDirection exitdir = TrackdirToExitdir(current->direction);
00223   TileIndex tile = current->tile;
00224   if (GetTunnelBridgeDirection(tile) == ReverseDiagDir(exitdir)) {
00225     /* We just popped out if this tunnel, since were
00226      * facing the tunnel exit */
00227     return NPF_TILE_LENGTH * (GetTunnelBridgeLength(current->tile, GetOtherTunnelEnd(current->tile)) + 1);
00228     /* @todo: Penalty for tunnels? */
00229   } else {
00230     /* We are entering the tunnel, the enter tile is just a
00231      * straight track */
00232     return NPF_TILE_LENGTH;
00233   }
00234 }
00235 
00236 static inline uint NPFBridgeCost(AyStarNode *current)
00237 {
00238   return NPF_TILE_LENGTH * GetTunnelBridgeLength(current->tile, GetOtherBridgeEnd(current->tile));
00239 }
00240 
00241 static uint NPFSlopeCost(AyStarNode *current)
00242 {
00243   TileIndex next = current->tile + TileOffsByDiagDir(TrackdirToExitdir(current->direction));
00244 
00245   /* Get center of tiles */
00246   int x1 = TileX(current->tile) * TILE_SIZE + TILE_SIZE / 2;
00247   int y1 = TileY(current->tile) * TILE_SIZE + TILE_SIZE / 2;
00248   int x2 = TileX(next) * TILE_SIZE + TILE_SIZE / 2;
00249   int y2 = TileY(next) * TILE_SIZE + TILE_SIZE / 2;
00250 
00251   int dx4 = (x2 - x1) / 4;
00252   int dy4 = (y2 - y1) / 4;
00253 
00254   /* Get the height on both sides of the tile edge.
00255    * Avoid testing the height on the tile-center. This will fail for halftile-foundations.
00256    */
00257   int z1 = GetSlopeZ(x1 + dx4, y1 + dy4);
00258   int z2 = GetSlopeZ(x2 - dx4, y2 - dy4);
00259 
00260   if (z2 - z1 > 1) {
00261     /* Slope up */
00262     return _settings_game.pf.npf.npf_rail_slope_penalty;
00263   }
00264   return 0;
00265   /* Should we give a bonus for slope down? Probably not, we
00266    * could just substract that bonus from the penalty, because
00267    * there is only one level of steepness... */
00268 }
00269 
00270 static uint NPFReservedTrackCost(AyStarNode *current)
00271 {
00272   TileIndex tile = current->tile;
00273   TrackBits track = TrackToTrackBits(TrackdirToTrack(current->direction));
00274   TrackBits res = GetReservedTrackbits(tile);
00275 
00276   if (NPFGetFlag(current, NPF_FLAG_3RD_SIGNAL) || NPFGetFlag(current, NPF_FLAG_LAST_SIGNAL_BLOCK) || ((res & track) == TRACK_BIT_NONE && !TracksOverlap(res | track))) return 0;
00277 
00278   if (IsTileType(tile, MP_TUNNELBRIDGE)) {
00279     DiagDirection exitdir = TrackdirToExitdir(current->direction);
00280     if (GetTunnelBridgeDirection(tile) == ReverseDiagDir(exitdir)) {
00281       return  _settings_game.pf.npf.npf_rail_pbs_cross_penalty * (GetTunnelBridgeLength(tile, GetOtherTunnelBridgeEnd(tile)) + 1);
00282     }
00283   }
00284   return  _settings_game.pf.npf.npf_rail_pbs_cross_penalty;
00285 }
00286 
00291 static void NPFMarkTile(TileIndex tile)
00292 {
00293 #ifndef NO_DEBUG_MESSAGES
00294   if (_debug_npf_level < 1 || _networking) return;
00295   switch (GetTileType(tile)) {
00296     case MP_RAILWAY:
00297       /* DEBUG: mark visited tiles by mowing the grass under them ;-) */
00298       if (!IsRailDepot(tile)) {
00299         SetRailGroundType(tile, RAIL_GROUND_BARREN);
00300         MarkTileDirtyByTile(tile);
00301       }
00302       break;
00303 
00304     case MP_ROAD:
00305       if (!IsRoadDepot(tile)) {
00306         SetRoadside(tile, ROADSIDE_BARREN);
00307         MarkTileDirtyByTile(tile);
00308       }
00309       break;
00310 
00311     default:
00312       break;
00313   }
00314 #endif
00315 }
00316 
00317 static int32 NPFWaterPathCost(AyStar *as, AyStarNode *current, OpenListNode *parent)
00318 {
00319   /* TileIndex tile = current->tile; */
00320   int32 cost = 0;
00321   Trackdir trackdir = current->direction;
00322 
00323   cost = _trackdir_length[trackdir]; // Should be different for diagonal tracks
00324 
00325   if (IsBuoyTile(current->tile) && IsDiagonalTrackdir(trackdir))
00326     cost += _settings_game.pf.npf.npf_buoy_penalty; // A small penalty for going over buoys
00327 
00328   if (current->direction != NextTrackdir((Trackdir)parent->path.node.direction))
00329     cost += _settings_game.pf.npf.npf_water_curve_penalty;
00330 
00331   /* @todo More penalties? */
00332 
00333   return cost;
00334 }
00335 
00336 /* Determine the cost of this node, for road tracks */
00337 static int32 NPFRoadPathCost(AyStar *as, AyStarNode *current, OpenListNode *parent)
00338 {
00339   TileIndex tile = current->tile;
00340   int32 cost = 0;
00341 
00342   /* Determine base length */
00343   switch (GetTileType(tile)) {
00344     case MP_TUNNELBRIDGE:
00345       cost = IsTunnel(tile) ? NPFTunnelCost(current) : NPFBridgeCost(current);
00346       break;
00347 
00348     case MP_ROAD:
00349       cost = NPF_TILE_LENGTH;
00350       /* Increase the cost for level crossings */
00351       if (IsLevelCrossing(tile)) cost += _settings_game.pf.npf.npf_crossing_penalty;
00352       break;
00353 
00354     case MP_STATION: {
00355       cost = NPF_TILE_LENGTH;
00356       const RoadStop *rs = RoadStop::GetByTile(tile, GetRoadStopType(tile));
00357       if (IsDriveThroughStopTile(tile)) {
00358         /* Increase the cost for drive-through road stops */
00359         cost += _settings_game.pf.npf.npf_road_drive_through_penalty;
00360         DiagDirection dir = TrackdirToExitdir(current->direction);
00361         if (!RoadStop::IsDriveThroughRoadStopContinuation(tile, tile - TileOffsByDiagDir(dir))) {
00362           /* When we're the first road stop in a 'queue' of them we increase
00363            * cost based on the fill percentage of the whole queue. */
00364           const RoadStop::Entry *entry = rs->GetEntry(dir);
00365           cost += entry->GetOccupied() * _settings_game.pf.npf.npf_road_dt_occupied_penalty / entry->GetLength();
00366         }
00367       } else {
00368         /* Increase cost for filled road stops */
00369         cost += _settings_game.pf.npf.npf_road_bay_occupied_penalty * (!rs->IsFreeBay(0) + !rs->IsFreeBay(1)) / 2;
00370       }
00371     } break;
00372 
00373     default:
00374       break;
00375   }
00376 
00377   /* Determine extra costs */
00378 
00379   /* Check for slope */
00380   cost += NPFSlopeCost(current);
00381 
00382   /* Check for turns. Road vehicles only really drive diagonal, turns are
00383    * represented by non-diagonal tracks */
00384   if (!IsDiagonalTrackdir(current->direction))
00385     cost += _settings_game.pf.npf.npf_road_curve_penalty;
00386 
00387   NPFMarkTile(tile);
00388   DEBUG(npf, 4, "Calculating G for: (%d, %d). Result: %d", TileX(current->tile), TileY(current->tile), cost);
00389   return cost;
00390 }
00391 
00392 
00393 /* Determine the cost of this node, for railway tracks */
00394 static int32 NPFRailPathCost(AyStar *as, AyStarNode *current, OpenListNode *parent)
00395 {
00396   TileIndex tile = current->tile;
00397   Trackdir trackdir = current->direction;
00398   int32 cost = 0;
00399   /* HACK: We create a OpenListNode manually, so we can call EndNodeCheck */
00400   OpenListNode new_node;
00401 
00402   /* Determine base length */
00403   switch (GetTileType(tile)) {
00404     case MP_TUNNELBRIDGE:
00405       cost = IsTunnel(tile) ? NPFTunnelCost(current) : NPFBridgeCost(current);
00406       break;
00407 
00408     case MP_RAILWAY:
00409       cost = _trackdir_length[trackdir]; // Should be different for diagonal tracks
00410       break;
00411 
00412     case MP_ROAD: // Railway crossing
00413       cost = NPF_TILE_LENGTH;
00414       break;
00415 
00416     case MP_STATION:
00417       /* We give a station tile a penalty. Logically we would only want to give
00418        * station tiles that are not our destination this penalty. This would
00419        * discourage trains to drive through busy stations. But, we can just
00420        * give any station tile a penalty, because every possible route will get
00421        * this penalty exactly once, on its end tile (if it's a station) and it
00422        * will therefore not make a difference. */
00423       cost = NPF_TILE_LENGTH + _settings_game.pf.npf.npf_rail_station_penalty;
00424 
00425       if (IsRailWaypoint(tile)) {
00426         NPFFindStationOrTileData *fstd = (NPFFindStationOrTileData*)as->user_target;
00427         if (fstd->v->current_order.IsType(OT_GOTO_WAYPOINT) && GetStationIndex(tile) == fstd->v->current_order.GetDestination()) {
00428           /* This waypoint is our destination; maybe this isn't an unreserved
00429            * one, so check that and if so see that as the last signal being
00430            * red. This way waypoints near stations should work better. */
00431           const Train *train = Train::From(fstd->v);
00432           CFollowTrackRail ft(train);
00433           TileIndex t = tile;
00434           Trackdir td = trackdir;
00435           while (ft.Follow(t, td)) {
00436             assert(t != ft.m_new_tile);
00437             t = ft.m_new_tile;
00438             if (KillFirstBit(ft.m_new_td_bits) != TRACKDIR_BIT_NONE) {
00439               /* We encountered a junction; it's going to be too complex to
00440                * handle this perfectly, so just bail out. There is no simple
00441                * free path, so try the other possibilities. */
00442               td = INVALID_TRACKDIR;
00443               break;
00444             }
00445             td = RemoveFirstTrackdir(&ft.m_new_td_bits);
00446             /* If this is a safe waiting position we're done searching for it */
00447             if (IsSafeWaitingPosition(train, t, td, true, _settings_game.pf.forbid_90_deg)) break;
00448           }
00449           if (td == INVALID_TRACKDIR ||
00450               !IsSafeWaitingPosition(train, t, td, true, _settings_game.pf.forbid_90_deg) ||
00451               !IsWaitingPositionFree(train, t, td, _settings_game.pf.forbid_90_deg)) {
00452             cost += _settings_game.pf.npf.npf_rail_lastred_penalty;
00453           }
00454         }
00455       }
00456       break;
00457 
00458     default:
00459       break;
00460   }
00461 
00462   /* Determine extra costs */
00463 
00464   /* Check for signals */
00465   if (IsTileType(tile, MP_RAILWAY)) {
00466     if (HasSignalOnTrackdir(tile, trackdir)) {
00467       SignalType sigtype = GetSignalType(tile, TrackdirToTrack(trackdir));
00468       /* Ordinary track with signals */
00469       if (GetSignalStateByTrackdir(tile, trackdir) == SIGNAL_STATE_RED) {
00470         /* Signal facing us is red */
00471         if (!NPFGetFlag(current, NPF_FLAG_SEEN_SIGNAL)) {
00472           /* Penalize the first signal we
00473            * encounter, if it is red */
00474 
00475           /* Is this a presignal exit or combo? */
00476           if (!IsPbsSignal(sigtype)) {
00477             if (sigtype == SIGTYPE_EXIT || sigtype == SIGTYPE_COMBO) {
00478               /* Penalise exit and combo signals differently (heavier) */
00479               cost += _settings_game.pf.npf.npf_rail_firstred_exit_penalty;
00480             } else {
00481               cost += _settings_game.pf.npf.npf_rail_firstred_penalty;
00482             }
00483           }
00484         }
00485         /* Record the state of this signal */
00486         NPFSetFlag(current, NPF_FLAG_LAST_SIGNAL_RED, true);
00487       } else {
00488         /* Record the state of this signal */
00489         NPFSetFlag(current, NPF_FLAG_LAST_SIGNAL_RED, false);
00490       }
00491       if (NPFGetFlag(current, NPF_FLAG_SEEN_SIGNAL)) {
00492         if (NPFGetFlag(current, NPF_FLAG_2ND_SIGNAL)) {
00493           NPFSetFlag(current, NPF_FLAG_3RD_SIGNAL, true);
00494         } else {
00495           NPFSetFlag(current, NPF_FLAG_2ND_SIGNAL, true);
00496         }
00497       } else {
00498         NPFSetFlag(current, NPF_FLAG_SEEN_SIGNAL, true);
00499       }
00500       NPFSetFlag(current, NPF_FLAG_LAST_SIGNAL_BLOCK, !IsPbsSignal(sigtype));
00501     }
00502 
00503     if (HasPbsSignalOnTrackdir(tile, ReverseTrackdir(trackdir)) && !NPFGetFlag(current, NPF_FLAG_3RD_SIGNAL)) {
00504       cost += _settings_game.pf.npf.npf_rail_pbs_signal_back_penalty;
00505     }
00506   }
00507 
00508   /* Penalise the tile if it is a target tile and the last signal was
00509    * red */
00510   /* HACK: We create a new_node here so we can call EndNodeCheck. Ugly as hell
00511    * of course... */
00512   new_node.path.node = *current;
00513   if (as->EndNodeCheck(as, &new_node) == AYSTAR_FOUND_END_NODE && NPFGetFlag(current, NPF_FLAG_LAST_SIGNAL_RED))
00514     cost += _settings_game.pf.npf.npf_rail_lastred_penalty;
00515 
00516   /* Check for slope */
00517   cost += NPFSlopeCost(current);
00518 
00519   /* Check for turns */
00520   if (current->direction != NextTrackdir((Trackdir)parent->path.node.direction))
00521     cost += _settings_game.pf.npf.npf_rail_curve_penalty;
00522   /* TODO, with realistic acceleration, also the amount of straight track between
00523    *      curves should be taken into account, as this affects the speed limit. */
00524 
00525   /* Check for reverse in depot */
00526   if (IsRailDepotTile(tile) && as->EndNodeCheck(as, &new_node) != AYSTAR_FOUND_END_NODE) {
00527     /* Penalise any depot tile that is not the last tile in the path. This
00528      * _should_ penalise every occurence of reversing in a depot (and only
00529      * that) */
00530     cost += _settings_game.pf.npf.npf_rail_depot_reverse_penalty;
00531   }
00532 
00533   /* Check for occupied track */
00534   cost += NPFReservedTrackCost(current);
00535 
00536   NPFMarkTile(tile);
00537   DEBUG(npf, 4, "Calculating G for: (%d, %d). Result: %d", TileX(current->tile), TileY(current->tile), cost);
00538   return cost;
00539 }
00540 
00541 /* Will find any depot */
00542 static int32 NPFFindDepot(AyStar *as, OpenListNode *current)
00543 {
00544   /* It's not worth caching the result with NPF_FLAG_IS_TARGET here as below,
00545    * since checking the cache not that much faster than the actual check */
00546   return IsDepotTypeTile(current->path.node.tile, (TransportType)as->user_data[NPF_TYPE]) ?
00547     AYSTAR_FOUND_END_NODE : AYSTAR_DONE;
00548 }
00549 
00551 static int32 NPFFindSafeTile(AyStar *as, OpenListNode *current)
00552 {
00553   const Train *v = Train::From(((NPFFindStationOrTileData *)as->user_target)->v);
00554 
00555   return
00556     IsSafeWaitingPosition(v, current->path.node.tile, current->path.node.direction, true, _settings_game.pf.forbid_90_deg) &&
00557     IsWaitingPositionFree(v, current->path.node.tile, current->path.node.direction, _settings_game.pf.forbid_90_deg) ?
00558       AYSTAR_FOUND_END_NODE : AYSTAR_DONE;
00559 }
00560 
00561 /* Will find a station identified using the NPFFindStationOrTileData */
00562 static int32 NPFFindStationOrTile(AyStar *as, OpenListNode *current)
00563 {
00564   NPFFindStationOrTileData *fstd = (NPFFindStationOrTileData*)as->user_target;
00565   AyStarNode *node = &current->path.node;
00566   TileIndex tile = node->tile;
00567 
00568   if (fstd->station_index == INVALID_STATION && tile == fstd->dest_coords) return AYSTAR_FOUND_END_NODE;
00569 
00570   if (IsTileType(tile, MP_STATION) && GetStationIndex(tile) == fstd->station_index) {
00571     if (fstd->v->type == VEH_TRAIN) return AYSTAR_FOUND_END_NODE;
00572 
00573     assert(fstd->v->type == VEH_ROAD);
00574     /* Only if it is a valid station *and* we can stop there */
00575     if (GetStationType(tile) == fstd->station_type && (fstd->not_articulated || IsDriveThroughStopTile(tile))) return AYSTAR_FOUND_END_NODE;
00576   }
00577   return AYSTAR_DONE;
00578 }
00579 
00587 static const PathNode *FindSafePosition(PathNode *path, const Train *v)
00588 {
00589   /* If there is no signal, reserve the whole path. */
00590   PathNode *sig = path;
00591 
00592   for (; path->parent != NULL; path = path->parent) {
00593     if (IsSafeWaitingPosition(v, path->node.tile, path->node.direction, true, _settings_game.pf.forbid_90_deg)) {
00594       sig = path;
00595     }
00596   }
00597 
00598   return sig;
00599 }
00600 
00604 static void ClearPathReservation(const PathNode *start, const PathNode *end)
00605 {
00606   bool first_run = true;
00607   for (; start != end; start = start->parent) {
00608     if (IsRailStationTile(start->node.tile) && first_run) {
00609       SetRailStationPlatformReservation(start->node.tile, TrackdirToExitdir(start->node.direction), false);
00610     } else {
00611       UnreserveRailTrack(start->node.tile, TrackdirToTrack(start->node.direction));
00612     }
00613     first_run = false;
00614   }
00615 }
00616 
00623 static void NPFSaveTargetData(AyStar *as, OpenListNode *current)
00624 {
00625   NPFFoundTargetData *ftd = (NPFFoundTargetData*)as->user_path;
00626   ftd->best_trackdir = (Trackdir)current->path.node.user_data[NPF_TRACKDIR_CHOICE];
00627   ftd->best_path_dist = current->g;
00628   ftd->best_bird_dist = 0;
00629   ftd->node = current->path.node;
00630   ftd->res_okay = false;
00631 
00632   if (as->user_target != NULL && ((NPFFindStationOrTileData*)as->user_target)->reserve_path && as->user_data[NPF_TYPE] == TRANSPORT_RAIL) {
00633     /* Path reservation is requested. */
00634     const Train *v = Train::From(((NPFFindStationOrTileData *)as->user_target)->v);
00635 
00636     const PathNode *target = FindSafePosition(&current->path, v);
00637     ftd->node = target->node;
00638 
00639     /* If the target is a station skip to platform end. */
00640     if (IsRailStationTile(target->node.tile)) {
00641       DiagDirection dir = TrackdirToExitdir(target->node.direction);
00642       uint len = Station::GetByTile(target->node.tile)->GetPlatformLength(target->node.tile, dir);
00643       TileIndex end_tile = TILE_ADD(target->node.tile, (len - 1) * TileOffsByDiagDir(dir));
00644 
00645       /* Update only end tile, trackdir of a station stays the same. */
00646       ftd->node.tile = end_tile;
00647       if (!IsWaitingPositionFree(v, end_tile, target->node.direction, _settings_game.pf.forbid_90_deg)) return;
00648       SetRailStationPlatformReservation(target->node.tile, dir, true);
00649       SetRailStationReservation(target->node.tile, false);
00650     } else {
00651       if (!IsWaitingPositionFree(v, target->node.tile, target->node.direction, _settings_game.pf.forbid_90_deg)) return;
00652     }
00653 
00654     for (const PathNode *cur = target; cur->parent != NULL; cur = cur->parent) {
00655       if (!TryReserveRailTrack(cur->node.tile, TrackdirToTrack(cur->node.direction))) {
00656         /* Reservation failed, undo. */
00657         ClearPathReservation(target, cur);
00658         return;
00659       }
00660     }
00661 
00662     ftd->res_okay = true;
00663   }
00664 }
00665 
00675 static bool CanEnterTileOwnerCheck(Owner owner, TileIndex tile, DiagDirection enterdir)
00676 {
00677   if (IsTileType(tile, MP_RAILWAY) || // Rail tile (also rail depot)
00678       HasStationTileRail(tile) ||     // Rail station tile/waypoint
00679       IsRoadDepotTile(tile) ||        // Road depot tile
00680       IsStandardRoadStopTile(tile)) { // Road station tile (but not drive-through stops)
00681     return IsTileOwner(tile, owner);  // You need to own these tiles entirely to use them
00682   }
00683 
00684   switch (GetTileType(tile)) {
00685     case MP_ROAD:
00686       /* rail-road crossing : are we looking at the railway part? */
00687       if (IsLevelCrossing(tile) &&
00688           DiagDirToAxis(enterdir) != GetCrossingRoadAxis(tile)) {
00689         return IsTileOwner(tile, owner); // Railway needs owner check, while the street is public
00690       }
00691       break;
00692 
00693     case MP_TUNNELBRIDGE:
00694       if (GetTunnelBridgeTransportType(tile) == TRANSPORT_RAIL) {
00695         return IsTileOwner(tile, owner);
00696       }
00697       break;
00698 
00699     default:
00700       break;
00701   }
00702 
00703   return true; // no need to check
00704 }
00705 
00706 
00710 static DiagDirection GetDepotDirection(TileIndex tile, TransportType type)
00711 {
00712   assert(IsDepotTypeTile(tile, type));
00713 
00714   switch (type) {
00715     case TRANSPORT_RAIL:  return GetRailDepotDirection(tile);
00716     case TRANSPORT_ROAD:  return GetRoadDepotDirection(tile);
00717     case TRANSPORT_WATER: return GetShipDepotDirection(tile);
00718     default: return INVALID_DIAGDIR; // Not reached
00719   }
00720 }
00721 
00723 static DiagDirection GetSingleTramBit(TileIndex tile)
00724 {
00725   if (IsNormalRoadTile(tile)) {
00726     RoadBits rb = GetRoadBits(tile, ROADTYPE_TRAM);
00727     switch (rb) {
00728       case ROAD_NW: return DIAGDIR_NW;
00729       case ROAD_SW: return DIAGDIR_SW;
00730       case ROAD_SE: return DIAGDIR_SE;
00731       case ROAD_NE: return DIAGDIR_NE;
00732       default: break;
00733     }
00734   }
00735   return INVALID_DIAGDIR;
00736 }
00737 
00748 static DiagDirection GetTileSingleEntry(TileIndex tile, TransportType type, uint subtype)
00749 {
00750   if (type != TRANSPORT_WATER && IsDepotTypeTile(tile, type)) return GetDepotDirection(tile, type);
00751 
00752   if (type == TRANSPORT_ROAD) {
00753     if (IsStandardRoadStopTile(tile)) return GetRoadStopDir(tile);
00754     if (HasBit(subtype, ROADTYPE_TRAM)) return GetSingleTramBit(tile);
00755   }
00756 
00757   return INVALID_DIAGDIR;
00758 }
00759 
00769 static inline bool ForceReverse(TileIndex tile, DiagDirection dir, TransportType type, uint subtype)
00770 {
00771   DiagDirection single_entry = GetTileSingleEntry(tile, type, subtype);
00772   return single_entry != INVALID_DIAGDIR && single_entry != dir;
00773 }
00774 
00786 static bool CanEnterTile(TileIndex tile, DiagDirection dir, TransportType type, uint subtype, RailTypes railtypes, Owner owner)
00787 {
00788   /* Check tunnel entries and bridge ramps */
00789   if (IsTileType(tile, MP_TUNNELBRIDGE) && GetTunnelBridgeDirection(tile) != dir) return false;
00790 
00791   /* Test ownership */
00792   if (!CanEnterTileOwnerCheck(owner, tile, dir)) return false;
00793 
00794   /* check correct rail type (mono, maglev, etc) */
00795   if (type == TRANSPORT_RAIL) {
00796     RailType rail_type = GetTileRailType(tile);
00797     if (!HasBit(railtypes, rail_type)) return false;
00798   }
00799 
00800   /* Depots, standard roadstops and single tram bits can only be entered from one direction */
00801   DiagDirection single_entry = GetTileSingleEntry(tile, type, subtype);
00802   if (single_entry != INVALID_DIAGDIR && single_entry != ReverseDiagDir(dir)) return false;
00803 
00804   return true;
00805 }
00806 
00818 static TrackdirBits GetDriveableTrackdirBits(TileIndex dst_tile, Trackdir src_trackdir, TransportType type, uint subtype)
00819 {
00820   TrackdirBits trackdirbits = TrackStatusToTrackdirBits(GetTileTrackStatus(dst_tile, type, subtype));
00821 
00822   if (trackdirbits == 0 && type == TRANSPORT_ROAD && HasBit(subtype, ROADTYPE_TRAM)) {
00823     /* GetTileTrackStatus() returns 0 for single tram bits.
00824      * As we cannot change it there (easily) without breaking something, change it here */
00825     switch (GetSingleTramBit(dst_tile)) {
00826       case DIAGDIR_NE:
00827       case DIAGDIR_SW:
00828         trackdirbits = TRACKDIR_BIT_X_NE | TRACKDIR_BIT_X_SW;
00829         break;
00830 
00831       case DIAGDIR_NW:
00832       case DIAGDIR_SE:
00833         trackdirbits = TRACKDIR_BIT_Y_NW | TRACKDIR_BIT_Y_SE;
00834         break;
00835 
00836       default: break;
00837     }
00838   }
00839 
00840   DEBUG(npf, 4, "Next node: (%d, %d) [%d], possible trackdirs: 0x%X", TileX(dst_tile), TileY(dst_tile), dst_tile, trackdirbits);
00841 
00842   /* Select only trackdirs we can reach from our current trackdir */
00843   trackdirbits &= TrackdirReachesTrackdirs(src_trackdir);
00844 
00845   /* Filter out trackdirs that would make 90 deg turns for trains */
00846   if (_settings_game.pf.forbid_90_deg && (type == TRANSPORT_RAIL || type == TRANSPORT_WATER)) trackdirbits &= ~TrackdirCrossesTrackdirs(src_trackdir);
00847 
00848   DEBUG(npf, 6, "After filtering: (%d, %d), possible trackdirs: 0x%X", TileX(dst_tile), TileY(dst_tile), trackdirbits);
00849 
00850   return trackdirbits;
00851 }
00852 
00853 
00854 /* Will just follow the results of GetTileTrackStatus concerning where we can
00855  * go and where not. Uses AyStar.user_data[NPF_TYPE] as the transport type and
00856  * an argument to GetTileTrackStatus. Will skip tunnels, meaning that the
00857  * entry and exit are neighbours. Will fill
00858  * AyStarNode.user_data[NPF_TRACKDIR_CHOICE] with an appropriate value, and
00859  * copy AyStarNode.user_data[NPF_NODE_FLAGS] from the parent */
00860 static void NPFFollowTrack(AyStar *aystar, OpenListNode *current)
00861 {
00862   /* We leave src_tile on track src_trackdir in direction src_exitdir */
00863   Trackdir src_trackdir = current->path.node.direction;
00864   TileIndex src_tile = current->path.node.tile;
00865   DiagDirection src_exitdir = TrackdirToExitdir(src_trackdir);
00866 
00867   /* Is src_tile valid, and can be used?
00868    * When choosing track on a junction src_tile is the tile neighboured to the junction wrt. exitdir.
00869    * 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. */
00870   bool ignore_src_tile = (current->path.parent == NULL && NPFGetFlag(&current->path.node, NPF_FLAG_IGNORE_START_TILE));
00871 
00872   /* Information about the vehicle: TransportType (road/rail/water) and SubType (compatible rail/road types) */
00873   TransportType type = (TransportType)aystar->user_data[NPF_TYPE];
00874   uint subtype = aystar->user_data[NPF_SUB_TYPE];
00875 
00876   /* Initialize to 0, so we can jump out (return) somewhere an have no neighbours */
00877   aystar->num_neighbours = 0;
00878   DEBUG(npf, 4, "Expanding: (%d, %d, %d) [%d]", TileX(src_tile), TileY(src_tile), src_trackdir, src_tile);
00879 
00880   /* We want to determine the tile we arrive, and which choices we have there */
00881   TileIndex dst_tile;
00882   TrackdirBits trackdirbits;
00883 
00884   /* Find dest tile */
00885   if (ignore_src_tile) {
00886     /* Do not perform any checks that involve src_tile */
00887     dst_tile = src_tile + TileOffsByDiagDir(src_exitdir);
00888     trackdirbits = GetDriveableTrackdirBits(dst_tile, src_trackdir, type, subtype);
00889   } else if (IsTileType(src_tile, MP_TUNNELBRIDGE) && GetTunnelBridgeDirection(src_tile) == src_exitdir) {
00890     /* We drive through the wormhole and arrive on the other side */
00891     dst_tile = GetOtherTunnelBridgeEnd(src_tile);
00892     trackdirbits = TrackdirToTrackdirBits(src_trackdir);
00893   } else if (ForceReverse(src_tile, src_exitdir, type, subtype)) {
00894     /* We can only reverse on this tile */
00895     dst_tile = src_tile;
00896     src_trackdir = ReverseTrackdir(src_trackdir);
00897     trackdirbits = TrackdirToTrackdirBits(src_trackdir);
00898   } else {
00899     /* We leave src_tile in src_exitdir and reach dst_tile */
00900     dst_tile = AddTileIndexDiffCWrap(src_tile, TileIndexDiffCByDiagDir(src_exitdir));
00901 
00902     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;
00903 
00904     if (dst_tile == INVALID_TILE) {
00905       /* We cannot enter the next tile. Road vehicles can reverse, others reach dead end */
00906       if (type != TRANSPORT_ROAD || HasBit(subtype, ROADTYPE_TRAM)) return;
00907 
00908       dst_tile = src_tile;
00909       src_trackdir = ReverseTrackdir(src_trackdir);
00910     }
00911 
00912     trackdirbits = GetDriveableTrackdirBits(dst_tile, src_trackdir, type, subtype);
00913 
00914     if (trackdirbits == 0) {
00915       /* We cannot enter the next tile. Road vehicles can reverse, others reach dead end */
00916       if (type != TRANSPORT_ROAD || HasBit(subtype, ROADTYPE_TRAM)) return;
00917 
00918       dst_tile = src_tile;
00919       src_trackdir = ReverseTrackdir(src_trackdir);
00920 
00921       trackdirbits = GetDriveableTrackdirBits(dst_tile, src_trackdir, type, subtype);
00922     }
00923   }
00924 
00925   if (NPFGetFlag(&current->path.node, NPF_FLAG_IGNORE_RESERVED)) {
00926     /* Mask out any reserved tracks. */
00927     TrackBits reserved = GetReservedTrackbits(dst_tile);
00928     trackdirbits &= ~TrackBitsToTrackdirBits(reserved);
00929 
00930     uint bits = TrackdirBitsToTrackBits(trackdirbits);
00931     int i;
00932     FOR_EACH_SET_BIT(i, bits) {
00933       if (TracksOverlap(reserved | TrackToTrackBits((Track)i))) trackdirbits &= ~TrackToTrackdirBits((Track)i);
00934     }
00935   }
00936 
00937   /* Enumerate possible track */
00938   uint i = 0;
00939   while (trackdirbits != 0) {
00940     Trackdir dst_trackdir = RemoveFirstTrackdir(&trackdirbits);
00941     DEBUG(npf, 5, "Expanded into trackdir: %d, remaining trackdirs: 0x%X", dst_trackdir, trackdirbits);
00942 
00943     /* Tile with signals? */
00944     if (IsTileType(dst_tile, MP_RAILWAY) && GetRailTileType(dst_tile) == RAIL_TILE_SIGNALS) {
00945       if (HasSignalOnTrackdir(dst_tile, ReverseTrackdir(dst_trackdir)) && !HasSignalOnTrackdir(dst_tile, dst_trackdir) && IsOnewaySignal(dst_tile, TrackdirToTrack(dst_trackdir)))
00946         /* If there's a one-way signal not pointing towards us, stop going in this direction. */
00947         break;
00948     }
00949     {
00950       /* We've found ourselves a neighbour :-) */
00951       AyStarNode *neighbour = &aystar->neighbours[i];
00952       neighbour->tile = dst_tile;
00953       neighbour->direction = dst_trackdir;
00954       /* Save user data */
00955       neighbour->user_data[NPF_NODE_FLAGS] = current->path.node.user_data[NPF_NODE_FLAGS];
00956       NPFFillTrackdirChoice(neighbour, current);
00957     }
00958     i++;
00959   }
00960   aystar->num_neighbours = i;
00961 }
00962 
00963 /*
00964  * Plan a route to the specified target (which is checked by target_proc),
00965  * from start1 and if not NULL, from start2 as well. The type of transport we
00966  * are checking is in type. reverse_penalty is applied to all routes that
00967  * originate from the second start node.
00968  * When we are looking for one specific target (optionally multiple tiles), we
00969  * should use a good heuristic to perform aystar search. When we search for
00970  * multiple targets that are spread around, we should perform a breadth first
00971  * search by specifiying CalcZero as our heuristic.
00972  */
00973 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)
00974 {
00975   int r;
00976   NPFFoundTargetData result;
00977 
00978   /* Initialize procs */
00979   _npf_aystar.CalculateH = heuristic_proc;
00980   _npf_aystar.EndNodeCheck = target_proc;
00981   _npf_aystar.FoundEndNode = NPFSaveTargetData;
00982   _npf_aystar.GetNeighbours = NPFFollowTrack;
00983   switch (type) {
00984     default: NOT_REACHED();
00985     case TRANSPORT_RAIL:  _npf_aystar.CalculateG = NPFRailPathCost;  break;
00986     case TRANSPORT_ROAD:  _npf_aystar.CalculateG = NPFRoadPathCost;  break;
00987     case TRANSPORT_WATER: _npf_aystar.CalculateG = NPFWaterPathCost; break;
00988   }
00989 
00990   /* Initialize Start Node(s) */
00991   start1->user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
00992   start1->user_data[NPF_NODE_FLAGS] = 0;
00993   NPFSetFlag(start1, NPF_FLAG_IGNORE_START_TILE, ignore_start_tile1);
00994   _npf_aystar.addstart(&_npf_aystar, start1, 0);
00995   if (start2) {
00996     start2->user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
00997     start2->user_data[NPF_NODE_FLAGS] = 0;
00998     NPFSetFlag(start2, NPF_FLAG_IGNORE_START_TILE, ignore_start_tile2);
00999     NPFSetFlag(start2, NPF_FLAG_REVERSE, true);
01000     _npf_aystar.addstart(&_npf_aystar, start2, reverse_penalty);
01001   }
01002 
01003   /* Initialize result */
01004   result.best_bird_dist = UINT_MAX;
01005   result.best_path_dist = UINT_MAX;
01006   result.best_trackdir  = INVALID_TRACKDIR;
01007   result.node.tile      = INVALID_TILE;
01008   result.res_okay       = false;
01009   _npf_aystar.user_path = &result;
01010 
01011   /* Initialize target */
01012   _npf_aystar.user_target = target;
01013 
01014   /* Initialize user_data */
01015   _npf_aystar.user_data[NPF_TYPE] = type;
01016   _npf_aystar.user_data[NPF_SUB_TYPE] = sub_type;
01017   _npf_aystar.user_data[NPF_OWNER] = owner;
01018   _npf_aystar.user_data[NPF_RAILTYPES] = railtypes;
01019 
01020   /* GO! */
01021   r = AyStarMain_Main(&_npf_aystar);
01022   assert(r != AYSTAR_STILL_BUSY);
01023 
01024   if (result.best_bird_dist != 0) {
01025     if (target != NULL) {
01026       DEBUG(npf, 1, "Could not find route to tile 0x%X from 0x%X.", target->dest_coords, start1->tile);
01027     } else {
01028       /* Assumption: target == NULL, so we are looking for a depot */
01029       DEBUG(npf, 1, "Could not find route to a depot from tile 0x%X.", start1->tile);
01030     }
01031 
01032   }
01033   return result;
01034 }
01035 
01036 /* Will search as below, but with two start nodes, the second being the
01037  * reverse. Look at the NPF_FLAG_REVERSE flag in the result node to see which
01038  * direction was taken (NPFGetFlag(result.node, NPF_FLAG_REVERSE)) */
01039 static 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)
01040 {
01041   AyStarNode start1;
01042   AyStarNode start2;
01043 
01044   start1.tile = tile1;
01045   start2.tile = tile2;
01046   /* We set this in case the target is also the start tile, we will just
01047    * return a not found then */
01048   start1.user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
01049   start1.direction = trackdir1;
01050   start2.direction = trackdir2;
01051   start2.user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
01052 
01053   return NPFRouteInternal(&start1, ignore_start_tile1, (IsValidTile(tile2) ? &start2 : NULL), ignore_start_tile2, target, NPFFindStationOrTile, NPFCalcStationOrTileHeuristic, type, sub_type, owner, railtypes, 0);
01054 }
01055 
01056 /* Will search from the given tile and direction, for a route to the given
01057  * station for the given transport type. See the declaration of
01058  * NPFFoundTargetData above for the meaning of the result. */
01059 static NPFFoundTargetData NPFRouteToStationOrTile(TileIndex tile, Trackdir trackdir, bool ignore_start_tile, NPFFindStationOrTileData *target, TransportType type, uint sub_type, Owner owner, RailTypes railtypes)
01060 {
01061   return NPFRouteToStationOrTileTwoWay(tile, trackdir, ignore_start_tile, INVALID_TILE, INVALID_TRACKDIR, false, target, type, sub_type, owner, railtypes);
01062 }
01063 
01064 /* Search using breadth first. Good for little track choice and inaccurate
01065  * heuristic, such as railway/road with two start nodes, the second being the reverse. Call
01066  * NPFGetFlag(result.node, NPF_FLAG_REVERSE) to see from which node the path
01067  * orginated. All pathfs from the second node will have the given
01068  * reverse_penalty applied (NPF_TILE_LENGTH is the equivalent of one full
01069  * tile).
01070  */
01071 static 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)
01072 {
01073   AyStarNode start1;
01074   AyStarNode start2;
01075 
01076   start1.tile = tile1;
01077   start2.tile = tile2;
01078   /* We set this in case the target is also the start tile, we will just
01079    * return a not found then */
01080   start1.user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
01081   start1.direction = trackdir1;
01082   start2.direction = trackdir2;
01083   start2.user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
01084 
01085   /* perform a breadth first search. Target is NULL,
01086    * since we are just looking for any depot...*/
01087   return NPFRouteInternal(&start1, ignore_start_tile1, (IsValidTile(tile2) ? &start2 : NULL), ignore_start_tile2, NULL, NPFFindDepot, NPFCalcZero, type, sub_type, owner, railtypes, reverse_penalty);
01088 }
01089 
01090 void InitializeNPF()
01091 {
01092   static bool first_init = true;
01093   if (first_init) {
01094     first_init = false;
01095     init_AyStar(&_npf_aystar, NPFHash, NPF_HASH_SIZE);
01096   } else {
01097     AyStarMain_Clear(&_npf_aystar);
01098   }
01099   _npf_aystar.loops_per_tick = 0;
01100   _npf_aystar.max_path_cost = 0;
01101   //_npf_aystar.max_search_nodes = 0;
01102   /* We will limit the number of nodes for now, until we have a better
01103    * solution to really fix performance */
01104   _npf_aystar.max_search_nodes = _settings_game.pf.npf.npf_max_search_nodes;
01105 }
01106 
01107 static void NPFFillWithOrderData(NPFFindStationOrTileData *fstd, const Vehicle *v, bool reserve_path = false)
01108 {
01109   /* Ships don't really reach their stations, but the tile in front. So don't
01110    * save the station id for ships. For roadvehs we don't store it either,
01111    * because multistop depends on vehicles actually reaching the exact
01112    * dest_tile, not just any stop of that station.
01113    * So only for train orders to stations we fill fstd->station_index, for all
01114    * others only dest_coords */
01115   if (v->type != VEH_SHIP && (v->current_order.IsType(OT_GOTO_STATION) || v->current_order.IsType(OT_GOTO_WAYPOINT))) {
01116     assert(v->type == VEH_TRAIN || v->type == VEH_ROAD);
01117     fstd->station_index = v->current_order.GetDestination();
01118     fstd->station_type = (v->type == VEH_TRAIN) ? (v->current_order.IsType(OT_GOTO_STATION) ? STATION_RAIL : STATION_WAYPOINT) : (RoadVehicle::From(v)->IsBus() ? STATION_BUS : STATION_TRUCK);
01119     fstd->not_articulated = v->type == VEH_ROAD && !RoadVehicle::From(v)->HasArticulatedPart();
01120     /* Let's take the closest tile of the station as our target for vehicles */
01121     fstd->dest_coords = CalcClosestStationTile(fstd->station_index, v->tile, fstd->station_type);
01122   } else {
01123     fstd->dest_coords = v->dest_tile;
01124     fstd->station_index = INVALID_STATION;
01125   }
01126   fstd->reserve_path = reserve_path;
01127   fstd->v = v;
01128 }
01129 
01130 /*** Road vehicles ***/
01131 
01132 FindDepotData NPFRoadVehicleFindNearestDepot(const RoadVehicle *v, int max_penalty)
01133 {
01134   Trackdir trackdir = v->GetVehicleTrackdir();
01135 
01136   NPFFoundTargetData ftd = NPFRouteToDepotBreadthFirstTwoWay(v->tile, trackdir, false, v->tile, ReverseTrackdir(trackdir), false, TRANSPORT_ROAD, v->compatible_roadtypes, v->owner, INVALID_RAILTYPES, 0);
01137 
01138   if (ftd.best_bird_dist != 0) return FindDepotData();
01139 
01140   /* Found target */
01141   /* Our caller expects a number of tiles, so we just approximate that
01142    * number by this. It might not be completely what we want, but it will
01143    * work for now :-) We can possibly change this when the old pathfinder
01144    * is removed. */
01145   return FindDepotData(ftd.node.tile, ftd.best_path_dist);
01146 }
01147 
01148 Trackdir NPFRoadVehicleChooseTrack(const RoadVehicle *v, TileIndex tile, DiagDirection enterdir, TrackdirBits trackdirs)
01149 {
01150   NPFFindStationOrTileData fstd;
01151 
01152   NPFFillWithOrderData(&fstd, v);
01153   Trackdir trackdir = DiagDirToDiagTrackdir(enterdir);
01154 
01155   NPFFoundTargetData ftd = NPFRouteToStationOrTile(tile - TileOffsByDiagDir(enterdir), trackdir, true, &fstd, TRANSPORT_ROAD, v->compatible_roadtypes, v->owner, INVALID_RAILTYPES);
01156   if (ftd.best_trackdir == INVALID_TRACKDIR) {
01157     /* We are already at our target. Just do something
01158      * @todo: maybe display error?
01159      * @todo: go straight ahead if possible? */
01160     return (Trackdir)FindFirstBit2x64(trackdirs);
01161   }
01162 
01163   /* If ftd.best_bird_dist is 0, we found our target and ftd.best_trackdir contains
01164    * the direction we need to take to get there, if ftd.best_bird_dist is not 0,
01165    * we did not find our target, but ftd.best_trackdir contains the direction leading
01166    * to the tile closest to our target. */
01167   return ftd.best_trackdir;
01168 }
01169 
01170 /*** Ships ***/
01171 
01172 Track NPFShipChooseTrack(const Ship *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks)
01173 {
01174   NPFFindStationOrTileData fstd;
01175   Trackdir trackdir = v->GetVehicleTrackdir();
01176   assert(trackdir != INVALID_TRACKDIR); // Check that we are not in a depot
01177 
01178   NPFFillWithOrderData(&fstd, v);
01179 
01180   NPFFoundTargetData ftd = NPFRouteToStationOrTile(tile - TileOffsByDiagDir(enterdir), trackdir, true, &fstd, TRANSPORT_WATER, 0, v->owner, INVALID_RAILTYPES);
01181 
01182   /* If ftd.best_bird_dist is 0, we found our target and ftd.best_trackdir contains
01183    * the direction we need to take to get there, if ftd.best_bird_dist is not 0,
01184    * we did not find our target, but ftd.best_trackdir contains the direction leading
01185    * to the tile closest to our target. */
01186   if (ftd.best_trackdir == 0xff) return INVALID_TRACK;
01187   return TrackdirToTrack(ftd.best_trackdir);
01188 }
01189 
01190 /*** Trains ***/
01191 
01192 FindDepotData NPFTrainFindNearestDepot(const Train *v, int max_penalty)
01193 {
01194   const Train *last = v->Last();
01195   Trackdir trackdir = v->GetVehicleTrackdir();
01196   Trackdir trackdir_rev = ReverseTrackdir(last->GetVehicleTrackdir());
01197 
01198   assert(trackdir != INVALID_TRACKDIR);
01199   NPFFoundTargetData ftd = NPFRouteToDepotBreadthFirstTwoWay(v->tile, trackdir, false, last->tile, trackdir_rev, false, TRANSPORT_RAIL, 0, v->owner, v->compatible_railtypes, NPF_INFINITE_PENALTY);
01200   if (ftd.best_bird_dist != 0) return FindDepotData();
01201 
01202   /* Found target */
01203   /* Our caller expects a number of tiles, so we just approximate that
01204    * number by this. It might not be completely what we want, but it will
01205    * work for now :-) We can possibly change this when the old pathfinder
01206    * is removed. */
01207   return FindDepotData(ftd.node.tile, ftd.best_path_dist, NPFGetFlag(&ftd.node, NPF_FLAG_REVERSE));
01208 }
01209 
01210 bool NPFTrainFindNearestSafeTile(const Train *v, TileIndex tile, Trackdir trackdir, bool override_railtype)
01211 {
01212   assert(v->type == VEH_TRAIN);
01213 
01214   NPFFindStationOrTileData fstd;
01215   fstd.v = v;
01216   fstd.reserve_path = true;
01217 
01218   AyStarNode start1;
01219   start1.tile = tile;
01220   /* We set this in case the target is also the start tile, we will just
01221    * return a not found then */
01222   start1.user_data[NPF_TRACKDIR_CHOICE] = INVALID_TRACKDIR;
01223   start1.direction = trackdir;
01224   NPFSetFlag(&start1, NPF_FLAG_IGNORE_RESERVED, true);
01225 
01226   RailTypes railtypes = v->compatible_railtypes;
01227   if (override_railtype) railtypes |= GetRailTypeInfo(v->railtype)->compatible_railtypes;
01228 
01229   /* perform a breadth first search. Target is NULL,
01230    * since we are just looking for any safe tile...*/
01231   return NPFRouteInternal(&start1, true, NULL, false, &fstd, NPFFindSafeTile, NPFCalcZero, TRANSPORT_RAIL, 0, v->owner, railtypes, 0).res_okay;
01232 }
01233 
01234 bool NPFTrainCheckReverse(const Train *v)
01235 {
01236   NPFFindStationOrTileData fstd;
01237   NPFFoundTargetData ftd;
01238   const Train *last = v->Last();
01239 
01240   NPFFillWithOrderData(&fstd, v);
01241 
01242   Trackdir trackdir = v->GetVehicleTrackdir();
01243   Trackdir trackdir_rev = ReverseTrackdir(last->GetVehicleTrackdir());
01244   assert(trackdir != INVALID_TRACKDIR);
01245   assert(trackdir_rev != INVALID_TRACKDIR);
01246 
01247   ftd = NPFRouteToStationOrTileTwoWay(v->tile, trackdir, false, last->tile, trackdir_rev, false, &fstd, TRANSPORT_RAIL, 0, v->owner, v->compatible_railtypes);
01248   /* If we didn't find anything, just keep on going straight ahead, otherwise take the reverse flag */
01249   return ftd.best_bird_dist != 0 && NPFGetFlag(&ftd.node, NPF_FLAG_REVERSE);
01250 }
01251 
01252 Track NPFTrainChooseTrack(const Train *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks, bool *path_not_found, bool reserve_track, struct PBSTileInfo *target)
01253 {
01254   NPFFindStationOrTileData fstd;
01255   NPFFillWithOrderData(&fstd, v, reserve_track);
01256 
01257   PBSTileInfo origin = FollowTrainReservation(v);
01258   assert(IsValidTrackdir(origin.trackdir));
01259 
01260   NPFFoundTargetData ftd = NPFRouteToStationOrTile(origin.tile, origin.trackdir, true, &fstd, TRANSPORT_RAIL, 0, v->owner, v->compatible_railtypes);
01261 
01262   if (target != NULL) {
01263     target->tile = ftd.node.tile;
01264     target->trackdir = (Trackdir)ftd.node.direction;
01265     target->okay = ftd.res_okay;
01266   }
01267 
01268   if (ftd.best_trackdir == INVALID_TRACKDIR) {
01269     /* We are already at our target. Just do something
01270      * @todo maybe display error?
01271      * @todo: go straight ahead if possible? */
01272     if (path_not_found) *path_not_found = false;
01273     return FindFirstTrack(tracks);
01274   }
01275 
01276   /* If ftd.best_bird_dist is 0, we found our target and ftd.best_trackdir contains
01277    * the direction we need to take to get there, if ftd.best_bird_dist is not 0,
01278    * we did not find our target, but ftd.best_trackdir contains the direction leading
01279    * to the tile closest to our target. */
01280   if (path_not_found != NULL) *path_not_found = (ftd.best_bird_dist != 0);
01281   /* Discard enterdir information, making it a normal track */
01282   return TrackdirToTrack(ftd.best_trackdir);
01283 }

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