train_cmd.cpp

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00001 /* $Id: train_cmd.cpp 24424 2012-07-20 19:45:31Z 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 "error.h"
00014 #include "articulated_vehicles.h"
00015 #include "command_func.h"
00016 #include "pathfinder/npf/npf_func.h"
00017 #include "pathfinder/yapf/yapf.hpp"
00018 #include "news_func.h"
00019 #include "company_func.h"
00020 #include "newgrf_sound.h"
00021 #include "newgrf_text.h"
00022 #include "strings_func.h"
00023 #include "viewport_func.h"
00024 #include "vehicle_func.h"
00025 #include "sound_func.h"
00026 #include "ai/ai.hpp"
00027 #include "game/game.hpp"
00028 #include "newgrf_station.h"
00029 #include "effectvehicle_func.h"
00030 #include "network/network.h"
00031 #include "spritecache.h"
00032 #include "core/random_func.hpp"
00033 #include "company_base.h"
00034 #include "newgrf.h"
00035 #include "order_backup.h"
00036 #include "zoom_func.h"
00037 
00038 #include "table/strings.h"
00039 #include "table/train_cmd.h"
00040 
00041 static Track ChooseTrainTrack(Train *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks, bool force_res, bool *got_reservation, bool mark_stuck);
00042 static bool TrainCheckIfLineEnds(Train *v, bool reverse = true);
00043 bool TrainController(Train *v, Vehicle *nomove, bool reverse = true); // Also used in vehicle_sl.cpp.
00044 static TileIndex TrainApproachingCrossingTile(const Train *v);
00045 static void CheckIfTrainNeedsService(Train *v);
00046 static void CheckNextTrainTile(Train *v);
00047 
00048 static const byte _vehicle_initial_x_fract[4] = {10, 8, 4,  8};
00049 static const byte _vehicle_initial_y_fract[4] = { 8, 4, 8, 10};
00050 
00051 
00059 static inline DiagDirection TrainExitDir(Direction direction, TrackBits track)
00060 {
00061   static const TrackBits state_dir_table[DIAGDIR_END] = { TRACK_BIT_RIGHT, TRACK_BIT_LOWER, TRACK_BIT_LEFT, TRACK_BIT_UPPER };
00062 
00063   DiagDirection diagdir = DirToDiagDir(direction);
00064 
00065   /* Determine the diagonal direction in which we will exit this tile */
00066   if (!HasBit(direction, 0) && track != state_dir_table[diagdir]) {
00067     diagdir = ChangeDiagDir(diagdir, DIAGDIRDIFF_90LEFT);
00068   }
00069 
00070   return diagdir;
00071 }
00072 
00073 
00079 byte FreightWagonMult(CargoID cargo)
00080 {
00081   if (!CargoSpec::Get(cargo)->is_freight) return 1;
00082   return _settings_game.vehicle.freight_trains;
00083 }
00084 
00086 void CheckTrainsLengths()
00087 {
00088   const Train *v;
00089   bool first = true;
00090 
00091   FOR_ALL_TRAINS(v) {
00092     if (v->First() == v && !(v->vehstatus & VS_CRASHED)) {
00093       for (const Train *u = v, *w = v->Next(); w != NULL; u = w, w = w->Next()) {
00094         if (u->track != TRACK_BIT_DEPOT) {
00095           if ((w->track != TRACK_BIT_DEPOT &&
00096               max(abs(u->x_pos - w->x_pos), abs(u->y_pos - w->y_pos)) != u->CalcNextVehicleOffset()) ||
00097               (w->track == TRACK_BIT_DEPOT && TicksToLeaveDepot(u) <= 0)) {
00098             SetDParam(0, v->index);
00099             SetDParam(1, v->owner);
00100             ShowErrorMessage(STR_BROKEN_VEHICLE_LENGTH, INVALID_STRING_ID, WL_CRITICAL);
00101 
00102             if (!_networking && first) {
00103               first = false;
00104               DoCommandP(0, PM_PAUSED_ERROR, 1, CMD_PAUSE);
00105             }
00106             /* Break so we warn only once for each train. */
00107             break;
00108           }
00109         }
00110       }
00111     }
00112   }
00113 }
00114 
00121 void Train::ConsistChanged(bool same_length)
00122 {
00123   uint16 max_speed = UINT16_MAX;
00124 
00125   assert(this->IsFrontEngine() || this->IsFreeWagon());
00126 
00127   const RailVehicleInfo *rvi_v = RailVehInfo(this->engine_type);
00128   EngineID first_engine = this->IsFrontEngine() ? this->engine_type : INVALID_ENGINE;
00129   this->gcache.cached_total_length = 0;
00130   this->compatible_railtypes = RAILTYPES_NONE;
00131 
00132   bool train_can_tilt = true;
00133 
00134   for (Train *u = this; u != NULL; u = u->Next()) {
00135     const RailVehicleInfo *rvi_u = RailVehInfo(u->engine_type);
00136 
00137     /* Check the this->first cache. */
00138     assert(u->First() == this);
00139 
00140     /* update the 'first engine' */
00141     u->gcache.first_engine = this == u ? INVALID_ENGINE : first_engine;
00142     u->railtype = rvi_u->railtype;
00143 
00144     if (u->IsEngine()) first_engine = u->engine_type;
00145 
00146     /* Set user defined data to its default value */
00147     u->tcache.user_def_data = rvi_u->user_def_data;
00148     this->InvalidateNewGRFCache();
00149     u->InvalidateNewGRFCache();
00150   }
00151 
00152   for (Train *u = this; u != NULL; u = u->Next()) {
00153     /* Update user defined data (must be done before other properties) */
00154     u->tcache.user_def_data = GetVehicleProperty(u, PROP_TRAIN_USER_DATA, u->tcache.user_def_data);
00155     this->InvalidateNewGRFCache();
00156     u->InvalidateNewGRFCache();
00157   }
00158 
00159   for (Train *u = this; u != NULL; u = u->Next()) {
00160     const Engine *e_u = u->GetEngine();
00161     const RailVehicleInfo *rvi_u = &e_u->u.rail;
00162 
00163     if (!HasBit(e_u->info.misc_flags, EF_RAIL_TILTS)) train_can_tilt = false;
00164 
00165     /* Cache wagon override sprite group. NULL is returned if there is none */
00166     u->tcache.cached_override = GetWagonOverrideSpriteSet(u->engine_type, u->cargo_type, u->gcache.first_engine);
00167 
00168     /* Reset colour map */
00169     u->colourmap = PAL_NONE;
00170 
00171     /* Update powered-wagon-status and visual effect */
00172     u->UpdateVisualEffect(true);
00173 
00174     if (rvi_v->pow_wag_power != 0 && rvi_u->railveh_type == RAILVEH_WAGON &&
00175         UsesWagonOverride(u) && !HasBit(u->vcache.cached_vis_effect, VE_DISABLE_WAGON_POWER)) {
00176       /* wagon is powered */
00177       SetBit(u->flags, VRF_POWEREDWAGON); // cache 'powered' status
00178     } else {
00179       ClrBit(u->flags, VRF_POWEREDWAGON);
00180     }
00181 
00182     if (!u->IsArticulatedPart()) {
00183       /* Do not count powered wagons for the compatible railtypes, as wagons always
00184          have railtype normal */
00185       if (rvi_u->power > 0) {
00186         this->compatible_railtypes |= GetRailTypeInfo(u->railtype)->powered_railtypes;
00187       }
00188 
00189       /* Some electric engines can be allowed to run on normal rail. It happens to all
00190        * existing electric engines when elrails are disabled and then re-enabled */
00191       if (HasBit(u->flags, VRF_EL_ENGINE_ALLOWED_NORMAL_RAIL)) {
00192         u->railtype = RAILTYPE_RAIL;
00193         u->compatible_railtypes |= RAILTYPES_RAIL;
00194       }
00195 
00196       /* max speed is the minimum of the speed limits of all vehicles in the consist */
00197       if ((rvi_u->railveh_type != RAILVEH_WAGON || _settings_game.vehicle.wagon_speed_limits) && !UsesWagonOverride(u)) {
00198         uint16 speed = GetVehicleProperty(u, PROP_TRAIN_SPEED, rvi_u->max_speed);
00199         if (speed != 0) max_speed = min(speed, max_speed);
00200       }
00201     }
00202 
00203     u->cargo_cap = e_u->DetermineCapacity(u);
00204     u->vcache.cached_cargo_age_period = GetVehicleProperty(u, PROP_TRAIN_CARGO_AGE_PERIOD, e_u->info.cargo_age_period);
00205 
00206     /* check the vehicle length (callback) */
00207     uint16 veh_len = CALLBACK_FAILED;
00208     if (e_u->GetGRF() != NULL && e_u->GetGRF()->grf_version >= 8) {
00209       /* Use callback 36 */
00210       veh_len = GetVehicleProperty(u, PROP_TRAIN_SHORTEN_FACTOR, CALLBACK_FAILED);
00211     } else if (HasBit(e_u->info.callback_mask, CBM_VEHICLE_LENGTH)) {
00212       /* Use callback 11 */
00213       veh_len = GetVehicleCallback(CBID_VEHICLE_LENGTH, 0, 0, u->engine_type, u);
00214     }
00215     if (veh_len != CALLBACK_FAILED && veh_len >= VEHICLE_LENGTH) {
00216       ErrorUnknownCallbackResult(e_u->GetGRFID(), CBID_VEHICLE_LENGTH, veh_len);
00217     }
00218     if (veh_len == CALLBACK_FAILED) veh_len = rvi_u->shorten_factor;
00219     veh_len = VEHICLE_LENGTH - Clamp(veh_len, 0, VEHICLE_LENGTH - 1);
00220 
00221     /* verify length hasn't changed */
00222     if (same_length && veh_len != u->gcache.cached_veh_length) VehicleLengthChanged(u);
00223 
00224     /* update vehicle length? */
00225     if (!same_length) u->gcache.cached_veh_length = veh_len;
00226 
00227     this->gcache.cached_total_length += u->gcache.cached_veh_length;
00228     this->InvalidateNewGRFCache();
00229     u->InvalidateNewGRFCache();
00230   }
00231 
00232   /* store consist weight/max speed in cache */
00233   this->vcache.cached_max_speed = max_speed;
00234   this->tcache.cached_tilt = train_can_tilt;
00235   this->tcache.cached_max_curve_speed = this->GetCurveSpeedLimit();
00236 
00237   /* recalculate cached weights and power too (we do this *after* the rest, so it is known which wagons are powered and need extra weight added) */
00238   this->CargoChanged();
00239 
00240   if (this->IsFrontEngine()) {
00241     this->UpdateAcceleration();
00242     SetWindowDirty(WC_VEHICLE_DETAILS, this->index);
00243     InvalidateWindowData(WC_VEHICLE_REFIT, this->index);
00244   }
00245 }
00246 
00257 int GetTrainStopLocation(StationID station_id, TileIndex tile, const Train *v, int *station_ahead, int *station_length)
00258 {
00259   const Station *st = Station::Get(station_id);
00260   *station_ahead  = st->GetPlatformLength(tile, DirToDiagDir(v->direction)) * TILE_SIZE;
00261   *station_length = st->GetPlatformLength(tile) * TILE_SIZE;
00262 
00263   /* Default to the middle of the station for stations stops that are not in
00264    * the order list like intermediate stations when non-stop is disabled */
00265   OrderStopLocation osl = OSL_PLATFORM_MIDDLE;
00266   if (v->gcache.cached_total_length >= *station_length) {
00267     /* The train is longer than the station, make it stop at the far end of the platform */
00268     osl = OSL_PLATFORM_FAR_END;
00269   } else if (v->current_order.IsType(OT_GOTO_STATION) && v->current_order.GetDestination() == station_id) {
00270     osl = v->current_order.GetStopLocation();
00271   }
00272 
00273   /* The stop location of the FRONT! of the train */
00274   int stop;
00275   switch (osl) {
00276     default: NOT_REACHED();
00277 
00278     case OSL_PLATFORM_NEAR_END:
00279       stop = v->gcache.cached_total_length;
00280       break;
00281 
00282     case OSL_PLATFORM_MIDDLE:
00283       stop = *station_length - (*station_length - v->gcache.cached_total_length) / 2;
00284       break;
00285 
00286     case OSL_PLATFORM_FAR_END:
00287       stop = *station_length;
00288       break;
00289   }
00290 
00291   /* Subtract half the front vehicle length of the train so we get the real
00292    * stop location of the train. */
00293   return stop - (v->gcache.cached_veh_length + 1) / 2;
00294 }
00295 
00296 
00301 int Train::GetCurveSpeedLimit() const
00302 {
00303   assert(this->First() == this);
00304 
00305   static const int absolute_max_speed = UINT16_MAX;
00306   int max_speed = absolute_max_speed;
00307 
00308   if (_settings_game.vehicle.train_acceleration_model == AM_ORIGINAL) return max_speed;
00309 
00310   int curvecount[2] = {0, 0};
00311 
00312   /* first find the curve speed limit */
00313   int numcurve = 0;
00314   int sum = 0;
00315   int pos = 0;
00316   int lastpos = -1;
00317   for (const Vehicle *u = this; u->Next() != NULL; u = u->Next(), pos++) {
00318     Direction this_dir = u->direction;
00319     Direction next_dir = u->Next()->direction;
00320 
00321     DirDiff dirdiff = DirDifference(this_dir, next_dir);
00322     if (dirdiff == DIRDIFF_SAME) continue;
00323 
00324     if (dirdiff == DIRDIFF_45LEFT) curvecount[0]++;
00325     if (dirdiff == DIRDIFF_45RIGHT) curvecount[1]++;
00326     if (dirdiff == DIRDIFF_45LEFT || dirdiff == DIRDIFF_45RIGHT) {
00327       if (lastpos != -1) {
00328         numcurve++;
00329         sum += pos - lastpos;
00330         if (pos - lastpos == 1 && max_speed > 88) {
00331           max_speed = 88;
00332         }
00333       }
00334       lastpos = pos;
00335     }
00336 
00337     /* if we have a 90 degree turn, fix the speed limit to 60 */
00338     if (dirdiff == DIRDIFF_90LEFT || dirdiff == DIRDIFF_90RIGHT) {
00339       max_speed = 61;
00340     }
00341   }
00342 
00343   if (numcurve > 0 && max_speed > 88) {
00344     if (curvecount[0] == 1 && curvecount[1] == 1) {
00345       max_speed = absolute_max_speed;
00346     } else {
00347       sum /= numcurve;
00348       max_speed = 232 - (13 - Clamp(sum, 1, 12)) * (13 - Clamp(sum, 1, 12));
00349     }
00350   }
00351 
00352   if (max_speed != absolute_max_speed) {
00353     /* Apply the engine's rail type curve speed advantage, if it slowed by curves */
00354     const RailtypeInfo *rti = GetRailTypeInfo(this->railtype);
00355     max_speed += (max_speed / 2) * rti->curve_speed;
00356 
00357     if (this->tcache.cached_tilt) {
00358       /* Apply max_speed bonus of 20% for a tilting train */
00359       max_speed += max_speed / 5;
00360     }
00361   }
00362 
00363   return max_speed;
00364 }
00365 
00370 int Train::GetCurrentMaxSpeed() const
00371 {
00372   int max_speed = this->tcache.cached_max_curve_speed;
00373   assert(max_speed == this->GetCurveSpeedLimit());
00374 
00375   if (IsRailStationTile(this->tile)) {
00376     StationID sid = GetStationIndex(this->tile);
00377     if (this->current_order.ShouldStopAtStation(this, sid)) {
00378       int station_ahead;
00379       int station_length;
00380       int stop_at = GetTrainStopLocation(sid, this->tile, this, &station_ahead, &station_length);
00381 
00382       /* The distance to go is whatever is still ahead of the train minus the
00383        * distance from the train's stop location to the end of the platform */
00384       int distance_to_go = station_ahead / TILE_SIZE - (station_length - stop_at) / TILE_SIZE;
00385 
00386       if (distance_to_go > 0) {
00387         int st_max_speed = 120;
00388 
00389         int delta_v = this->cur_speed / (distance_to_go + 1);
00390         if (max_speed > (this->cur_speed - delta_v)) {
00391           st_max_speed = this->cur_speed - (delta_v / 10);
00392         }
00393 
00394         st_max_speed = max(st_max_speed, 25 * distance_to_go);
00395         max_speed = min(max_speed, st_max_speed);
00396       }
00397     }
00398   }
00399 
00400   for (const Train *u = this; u != NULL; u = u->Next()) {
00401     if (u->track == TRACK_BIT_DEPOT) {
00402       max_speed = min(max_speed, 61);
00403       break;
00404     }
00405   }
00406 
00407   max_speed = min(max_speed, this->current_order.max_speed);
00408   return min(max_speed, this->gcache.cached_max_track_speed);
00409 }
00410 
00412 void Train::UpdateAcceleration()
00413 {
00414   assert(this->IsFrontEngine());
00415 
00416   uint power = this->gcache.cached_power;
00417   uint weight = this->gcache.cached_weight;
00418   assert(weight != 0);
00419   this->acceleration = Clamp(power / weight * 4, 1, 255);
00420 }
00421 
00427 int Train::GetDisplayImageWidth(Point *offset) const
00428 {
00429   int reference_width = TRAININFO_DEFAULT_VEHICLE_WIDTH;
00430   int vehicle_pitch = 0;
00431 
00432   const Engine *e = this->GetEngine();
00433   if (e->GetGRF() != NULL && is_custom_sprite(e->u.rail.image_index)) {
00434     reference_width = e->GetGRF()->traininfo_vehicle_width;
00435     vehicle_pitch = e->GetGRF()->traininfo_vehicle_pitch;
00436   }
00437 
00438   if (offset != NULL) {
00439     offset->x = reference_width / 2;
00440     offset->y = vehicle_pitch;
00441   }
00442   return this->gcache.cached_veh_length * reference_width / VEHICLE_LENGTH;
00443 }
00444 
00445 static SpriteID GetDefaultTrainSprite(uint8 spritenum, Direction direction)
00446 {
00447   return ((direction + _engine_sprite_add[spritenum]) & _engine_sprite_and[spritenum]) + _engine_sprite_base[spritenum];
00448 }
00449 
00456 SpriteID Train::GetImage(Direction direction, EngineImageType image_type) const
00457 {
00458   uint8 spritenum = this->spritenum;
00459   SpriteID sprite;
00460 
00461   if (HasBit(this->flags, VRF_REVERSE_DIRECTION)) direction = ReverseDir(direction);
00462 
00463   if (is_custom_sprite(spritenum)) {
00464     sprite = GetCustomVehicleSprite(this, (Direction)(direction + 4 * IS_CUSTOM_SECONDHEAD_SPRITE(spritenum)), image_type);
00465     if (sprite != 0) return sprite;
00466 
00467     spritenum = this->GetEngine()->original_image_index;
00468   }
00469 
00470   sprite = GetDefaultTrainSprite(spritenum, direction);
00471 
00472   if (this->cargo.Count() >= this->cargo_cap / 2U) sprite += _wagon_full_adder[spritenum];
00473 
00474   return sprite;
00475 }
00476 
00477 static SpriteID GetRailIcon(EngineID engine, bool rear_head, int &y, EngineImageType image_type)
00478 {
00479   const Engine *e = Engine::Get(engine);
00480   Direction dir = rear_head ? DIR_E : DIR_W;
00481   uint8 spritenum = e->u.rail.image_index;
00482 
00483   if (is_custom_sprite(spritenum)) {
00484     SpriteID sprite = GetCustomVehicleIcon(engine, dir, image_type);
00485     if (sprite != 0) {
00486       if (e->GetGRF() != NULL) {
00487         y += e->GetGRF()->traininfo_vehicle_pitch;
00488       }
00489       return sprite;
00490     }
00491 
00492     spritenum = Engine::Get(engine)->original_image_index;
00493   }
00494 
00495   if (rear_head) spritenum++;
00496 
00497   return GetDefaultTrainSprite(spritenum, DIR_W);
00498 }
00499 
00500 void DrawTrainEngine(int left, int right, int preferred_x, int y, EngineID engine, PaletteID pal, EngineImageType image_type)
00501 {
00502   if (RailVehInfo(engine)->railveh_type == RAILVEH_MULTIHEAD) {
00503     int yf = y;
00504     int yr = y;
00505 
00506     SpriteID spritef = GetRailIcon(engine, false, yf, image_type);
00507     SpriteID spriter = GetRailIcon(engine, true, yr, image_type);
00508     const Sprite *real_spritef = GetSprite(spritef, ST_NORMAL);
00509     const Sprite *real_spriter = GetSprite(spriter, ST_NORMAL);
00510 
00511     preferred_x = Clamp(preferred_x, left - UnScaleByZoom(real_spritef->x_offs, ZOOM_LVL_GUI) + 14, right - UnScaleByZoom(real_spriter->width, ZOOM_LVL_GUI) - UnScaleByZoom(real_spriter->x_offs, ZOOM_LVL_GUI) - 15);
00512 
00513     DrawSprite(spritef, pal, preferred_x - 14, yf);
00514     DrawSprite(spriter, pal, preferred_x + 15, yr);
00515   } else {
00516     SpriteID sprite = GetRailIcon(engine, false, y, image_type);
00517     const Sprite *real_sprite = GetSprite(sprite, ST_NORMAL);
00518     preferred_x = Clamp(preferred_x, left - UnScaleByZoom(real_sprite->x_offs, ZOOM_LVL_GUI), right - UnScaleByZoom(real_sprite->width, ZOOM_LVL_GUI) - UnScaleByZoom(real_sprite->x_offs, ZOOM_LVL_GUI));
00519     DrawSprite(sprite, pal, preferred_x, y);
00520   }
00521 }
00522 
00531 static CommandCost CmdBuildRailWagon(TileIndex tile, DoCommandFlag flags, const Engine *e, Vehicle **ret)
00532 {
00533   const RailVehicleInfo *rvi = &e->u.rail;
00534 
00535   /* Check that the wagon can drive on the track in question */
00536   if (!IsCompatibleRail(rvi->railtype, GetRailType(tile))) return CMD_ERROR;
00537 
00538   if (flags & DC_EXEC) {
00539     Train *v = new Train();
00540     *ret = v;
00541     v->spritenum = rvi->image_index;
00542 
00543     v->engine_type = e->index;
00544     v->gcache.first_engine = INVALID_ENGINE; // needs to be set before first callback
00545 
00546     DiagDirection dir = GetRailDepotDirection(tile);
00547 
00548     v->direction = DiagDirToDir(dir);
00549     v->tile = tile;
00550 
00551     int x = TileX(tile) * TILE_SIZE | _vehicle_initial_x_fract[dir];
00552     int y = TileY(tile) * TILE_SIZE | _vehicle_initial_y_fract[dir];
00553 
00554     v->x_pos = x;
00555     v->y_pos = y;
00556     v->z_pos = GetSlopePixelZ(x, y);
00557     v->owner = _current_company;
00558     v->track = TRACK_BIT_DEPOT;
00559     v->vehstatus = VS_HIDDEN | VS_DEFPAL;
00560 
00561     v->SetWagon();
00562 
00563     v->SetFreeWagon();
00564     InvalidateWindowData(WC_VEHICLE_DEPOT, v->tile);
00565 
00566     v->cargo_type = e->GetDefaultCargoType();
00567     v->cargo_cap = rvi->capacity;
00568 
00569     v->railtype = rvi->railtype;
00570 
00571     v->build_year = _cur_year;
00572     v->cur_image = SPR_IMG_QUERY;
00573     v->random_bits = VehicleRandomBits();
00574 
00575     v->group_id = DEFAULT_GROUP;
00576 
00577     AddArticulatedParts(v);
00578 
00579     _new_vehicle_id = v->index;
00580 
00581     VehicleUpdatePosition(v);
00582     v->First()->ConsistChanged(false);
00583     UpdateTrainGroupID(v->First());
00584 
00585     CheckConsistencyOfArticulatedVehicle(v);
00586 
00587     /* Try to connect the vehicle to one of free chains of wagons. */
00588     Train *w;
00589     FOR_ALL_TRAINS(w) {
00590       if (w->tile == tile &&              
00591           w->IsFreeWagon() &&             
00592           w->engine_type == e->index &&   
00593           w->First() != v &&              
00594           !(w->vehstatus & VS_CRASHED)) { 
00595         DoCommand(0, v->index | 1 << 20, w->Last()->index, DC_EXEC, CMD_MOVE_RAIL_VEHICLE);
00596         break;
00597       }
00598     }
00599   }
00600 
00601   return CommandCost();
00602 }
00603 
00605 static void NormalizeTrainVehInDepot(const Train *u)
00606 {
00607   const Train *v;
00608   FOR_ALL_TRAINS(v) {
00609     if (v->IsFreeWagon() && v->tile == u->tile &&
00610         v->track == TRACK_BIT_DEPOT) {
00611       if (DoCommand(0, v->index | 1 << 20, u->index, DC_EXEC,
00612           CMD_MOVE_RAIL_VEHICLE).Failed())
00613         break;
00614     }
00615   }
00616 }
00617 
00618 static void AddRearEngineToMultiheadedTrain(Train *v)
00619 {
00620   Train *u = new Train();
00621   v->value >>= 1;
00622   u->value = v->value;
00623   u->direction = v->direction;
00624   u->owner = v->owner;
00625   u->tile = v->tile;
00626   u->x_pos = v->x_pos;
00627   u->y_pos = v->y_pos;
00628   u->z_pos = v->z_pos;
00629   u->track = TRACK_BIT_DEPOT;
00630   u->vehstatus = v->vehstatus & ~VS_STOPPED;
00631   u->spritenum = v->spritenum + 1;
00632   u->cargo_type = v->cargo_type;
00633   u->cargo_subtype = v->cargo_subtype;
00634   u->cargo_cap = v->cargo_cap;
00635   u->railtype = v->railtype;
00636   u->engine_type = v->engine_type;
00637   u->build_year = v->build_year;
00638   u->cur_image = SPR_IMG_QUERY;
00639   u->random_bits = VehicleRandomBits();
00640   v->SetMultiheaded();
00641   u->SetMultiheaded();
00642   v->SetNext(u);
00643   VehicleUpdatePosition(u);
00644 
00645   /* Now we need to link the front and rear engines together */
00646   v->other_multiheaded_part = u;
00647   u->other_multiheaded_part = v;
00648 }
00649 
00659 CommandCost CmdBuildRailVehicle(TileIndex tile, DoCommandFlag flags, const Engine *e, uint16 data, Vehicle **ret)
00660 {
00661   const RailVehicleInfo *rvi = &e->u.rail;
00662 
00663   if (rvi->railveh_type == RAILVEH_WAGON) return CmdBuildRailWagon(tile, flags, e, ret);
00664 
00665   /* Check if depot and new engine uses the same kind of tracks *
00666    * We need to see if the engine got power on the tile to avoid electric engines in non-electric depots */
00667   if (!HasPowerOnRail(rvi->railtype, GetRailType(tile))) return CMD_ERROR;
00668 
00669   if (flags & DC_EXEC) {
00670     DiagDirection dir = GetRailDepotDirection(tile);
00671     int x = TileX(tile) * TILE_SIZE + _vehicle_initial_x_fract[dir];
00672     int y = TileY(tile) * TILE_SIZE + _vehicle_initial_y_fract[dir];
00673 
00674     Train *v = new Train();
00675     *ret = v;
00676     v->direction = DiagDirToDir(dir);
00677     v->tile = tile;
00678     v->owner = _current_company;
00679     v->x_pos = x;
00680     v->y_pos = y;
00681     v->z_pos = GetSlopePixelZ(x, y);
00682     v->track = TRACK_BIT_DEPOT;
00683     v->vehstatus = VS_HIDDEN | VS_STOPPED | VS_DEFPAL;
00684     v->spritenum = rvi->image_index;
00685     v->cargo_type = e->GetDefaultCargoType();
00686     v->cargo_cap = rvi->capacity;
00687     v->last_station_visited = INVALID_STATION;
00688 
00689     v->engine_type = e->index;
00690     v->gcache.first_engine = INVALID_ENGINE; // needs to be set before first callback
00691 
00692     v->reliability = e->reliability;
00693     v->reliability_spd_dec = e->reliability_spd_dec;
00694     v->max_age = e->GetLifeLengthInDays();
00695 
00696     v->railtype = rvi->railtype;
00697     _new_vehicle_id = v->index;
00698 
00699     v->service_interval = Company::Get(_current_company)->settings.vehicle.servint_trains;
00700     v->date_of_last_service = _date;
00701     v->build_year = _cur_year;
00702     v->cur_image = SPR_IMG_QUERY;
00703     v->random_bits = VehicleRandomBits();
00704 
00705     if (e->flags & ENGINE_EXCLUSIVE_PREVIEW) SetBit(v->vehicle_flags, VF_BUILT_AS_PROTOTYPE);
00706 
00707     v->group_id = DEFAULT_GROUP;
00708 
00709     v->SetFrontEngine();
00710     v->SetEngine();
00711 
00712     VehicleUpdatePosition(v);
00713 
00714     if (rvi->railveh_type == RAILVEH_MULTIHEAD) {
00715       AddRearEngineToMultiheadedTrain(v);
00716     } else {
00717       AddArticulatedParts(v);
00718     }
00719 
00720     v->ConsistChanged(false);
00721     UpdateTrainGroupID(v);
00722 
00723     if (!HasBit(data, 0) && !(flags & DC_AUTOREPLACE)) { // check if the cars should be added to the new vehicle
00724       NormalizeTrainVehInDepot(v);
00725     }
00726 
00727     CheckConsistencyOfArticulatedVehicle(v);
00728   }
00729 
00730   return CommandCost();
00731 }
00732 
00733 static Train *FindGoodVehiclePos(const Train *src)
00734 {
00735   EngineID eng = src->engine_type;
00736   TileIndex tile = src->tile;
00737 
00738   Train *dst;
00739   FOR_ALL_TRAINS(dst) {
00740     if (dst->IsFreeWagon() && dst->tile == tile && !(dst->vehstatus & VS_CRASHED)) {
00741       /* check so all vehicles in the line have the same engine. */
00742       Train *t = dst;
00743       while (t->engine_type == eng) {
00744         t = t->Next();
00745         if (t == NULL) return dst;
00746       }
00747     }
00748   }
00749 
00750   return NULL;
00751 }
00752 
00754 typedef SmallVector<Train *, 16> TrainList;
00755 
00761 static void MakeTrainBackup(TrainList &list, Train *t)
00762 {
00763   for (; t != NULL; t = t->Next()) *list.Append() = t;
00764 }
00765 
00770 static void RestoreTrainBackup(TrainList &list)
00771 {
00772   /* No train, nothing to do. */
00773   if (list.Length() == 0) return;
00774 
00775   Train *prev = NULL;
00776   /* Iterate over the list and rebuild it. */
00777   for (Train **iter = list.Begin(); iter != list.End(); iter++) {
00778     Train *t = *iter;
00779     if (prev != NULL) {
00780       prev->SetNext(t);
00781     } else if (t->Previous() != NULL) {
00782       /* Make sure the head of the train is always the first in the chain. */
00783       t->Previous()->SetNext(NULL);
00784     }
00785     prev = t;
00786   }
00787 }
00788 
00794 static void RemoveFromConsist(Train *part, bool chain = false)
00795 {
00796   Train *tail = chain ? part->Last() : part->GetLastEnginePart();
00797 
00798   /* Unlink at the front, but make it point to the next
00799    * vehicle after the to be remove part. */
00800   if (part->Previous() != NULL) part->Previous()->SetNext(tail->Next());
00801 
00802   /* Unlink at the back */
00803   tail->SetNext(NULL);
00804 }
00805 
00811 static void InsertInConsist(Train *dst, Train *chain)
00812 {
00813   /* We do not want to add something in the middle of an articulated part. */
00814   assert(dst->Next() == NULL || !dst->Next()->IsArticulatedPart());
00815 
00816   chain->Last()->SetNext(dst->Next());
00817   dst->SetNext(chain);
00818 }
00819 
00825 static void NormaliseDualHeads(Train *t)
00826 {
00827   for (; t != NULL; t = t->GetNextVehicle()) {
00828     if (!t->IsMultiheaded() || !t->IsEngine()) continue;
00829 
00830     /* Make sure that there are no free cars before next engine */
00831     Train *u;
00832     for (u = t; u->Next() != NULL && !u->Next()->IsEngine(); u = u->Next()) {}
00833 
00834     if (u == t->other_multiheaded_part) continue;
00835 
00836     /* Remove the part from the 'wrong' train */
00837     RemoveFromConsist(t->other_multiheaded_part);
00838     /* And add it to the 'right' train */
00839     InsertInConsist(u, t->other_multiheaded_part);
00840   }
00841 }
00842 
00847 static void NormaliseSubtypes(Train *chain)
00848 {
00849   /* Nothing to do */
00850   if (chain == NULL) return;
00851 
00852   /* We must be the first in the chain. */
00853   assert(chain->Previous() == NULL);
00854 
00855   /* Set the appropriate bits for the first in the chain. */
00856   if (chain->IsWagon()) {
00857     chain->SetFreeWagon();
00858   } else {
00859     assert(chain->IsEngine());
00860     chain->SetFrontEngine();
00861   }
00862 
00863   /* Now clear the bits for the rest of the chain */
00864   for (Train *t = chain->Next(); t != NULL; t = t->Next()) {
00865     t->ClearFreeWagon();
00866     t->ClearFrontEngine();
00867   }
00868 }
00869 
00879 static CommandCost CheckNewTrain(Train *original_dst, Train *dst, Train *original_src, Train *src)
00880 {
00881   /* Just add 'new' engines and subtract the original ones.
00882    * If that's less than or equal to 0 we can be sure we did
00883    * not add any engines (read: trains) along the way. */
00884   if ((src          != NULL && src->IsEngine()          ? 1 : 0) +
00885       (dst          != NULL && dst->IsEngine()          ? 1 : 0) -
00886       (original_src != NULL && original_src->IsEngine() ? 1 : 0) -
00887       (original_dst != NULL && original_dst->IsEngine() ? 1 : 0) <= 0) {
00888     return CommandCost();
00889   }
00890 
00891   /* Get a free unit number and check whether it's within the bounds.
00892    * There will always be a maximum of one new train. */
00893   if (GetFreeUnitNumber(VEH_TRAIN) <= _settings_game.vehicle.max_trains) return CommandCost();
00894 
00895   return_cmd_error(STR_ERROR_TOO_MANY_VEHICLES_IN_GAME);
00896 }
00897 
00903 static CommandCost CheckTrainAttachment(Train *t)
00904 {
00905   /* No multi-part train, no need to check. */
00906   if (t == NULL || t->Next() == NULL || !t->IsEngine()) return CommandCost();
00907 
00908   /* The maximum length for a train. For each part we decrease this by one
00909    * and if the result is negative the train is simply too long. */
00910   int allowed_len = _settings_game.vehicle.max_train_length * TILE_SIZE - t->gcache.cached_veh_length;
00911 
00912   Train *head = t;
00913   Train *prev = t;
00914 
00915   /* Break the prev -> t link so it always holds within the loop. */
00916   t = t->Next();
00917   prev->SetNext(NULL);
00918 
00919   /* Make sure the cache is cleared. */
00920   head->InvalidateNewGRFCache();
00921 
00922   while (t != NULL) {
00923     allowed_len -= t->gcache.cached_veh_length;
00924 
00925     Train *next = t->Next();
00926 
00927     /* Unlink the to-be-added piece; it is already unlinked from the previous
00928      * part due to the fact that the prev -> t link is broken. */
00929     t->SetNext(NULL);
00930 
00931     /* Don't check callback for articulated or rear dual headed parts */
00932     if (!t->IsArticulatedPart() && !t->IsRearDualheaded()) {
00933       /* Back up and clear the first_engine data to avoid using wagon override group */
00934       EngineID first_engine = t->gcache.first_engine;
00935       t->gcache.first_engine = INVALID_ENGINE;
00936 
00937       /* We don't want the cache to interfere. head's cache is cleared before
00938        * the loop and after each callback does not need to be cleared here. */
00939       t->InvalidateNewGRFCache();
00940 
00941       uint16 callback = GetVehicleCallbackParent(CBID_TRAIN_ALLOW_WAGON_ATTACH, 0, 0, head->engine_type, t, head);
00942 
00943       /* Restore original first_engine data */
00944       t->gcache.first_engine = first_engine;
00945 
00946       /* We do not want to remember any cached variables from the test run */
00947       t->InvalidateNewGRFCache();
00948       head->InvalidateNewGRFCache();
00949 
00950       if (callback != CALLBACK_FAILED) {
00951         /* A failing callback means everything is okay */
00952         StringID error = STR_NULL;
00953 
00954         if (head->GetGRF()->grf_version < 8) {
00955           if (callback == 0xFD) error = STR_ERROR_INCOMPATIBLE_RAIL_TYPES;
00956           if (callback  < 0xFD) error = GetGRFStringID(head->GetGRFID(), 0xD000 + callback);
00957           if (callback >= 0x100) ErrorUnknownCallbackResult(head->GetGRFID(), CBID_TRAIN_ALLOW_WAGON_ATTACH, callback);
00958         } else {
00959           if (callback < 0x400) {
00960             error = GetGRFStringID(head->GetGRFID(), 0xD000 + callback);
00961           } else {
00962             switch (callback) {
00963               case 0x400: // allow if railtypes match (always the case for OpenTTD)
00964               case 0x401: // allow
00965                 break;
00966 
00967               default:    // unknown reason -> disallow
00968               case 0x402: // disallow attaching
00969                 error = STR_ERROR_INCOMPATIBLE_RAIL_TYPES;
00970                 break;
00971             }
00972           }
00973         }
00974 
00975         if (error != STR_NULL) return_cmd_error(error);
00976       }
00977     }
00978 
00979     /* And link it to the new part. */
00980     prev->SetNext(t);
00981     prev = t;
00982     t = next;
00983   }
00984 
00985   if (allowed_len < 0) return_cmd_error(STR_ERROR_TRAIN_TOO_LONG);
00986   return CommandCost();
00987 }
00988 
00999 static CommandCost ValidateTrains(Train *original_dst, Train *dst, Train *original_src, Train *src, bool check_limit)
01000 {
01001   /* Check whether we may actually construct the trains. */
01002   CommandCost ret = CheckTrainAttachment(src);
01003   if (ret.Failed()) return ret;
01004   ret = CheckTrainAttachment(dst);
01005   if (ret.Failed()) return ret;
01006 
01007   /* Check whether we need to build a new train. */
01008   return check_limit ? CheckNewTrain(original_dst, dst, original_src, src) : CommandCost();
01009 }
01010 
01019 static void ArrangeTrains(Train **dst_head, Train *dst, Train **src_head, Train *src, bool move_chain)
01020 {
01021   /* First determine the front of the two resulting trains */
01022   if (*src_head == *dst_head) {
01023     /* If we aren't moving part(s) to a new train, we are just moving the
01024      * front back and there is not destination head. */
01025     *dst_head = NULL;
01026   } else if (*dst_head == NULL) {
01027     /* If we are moving to a new train the head of the move train would become
01028      * the head of the new vehicle. */
01029     *dst_head = src;
01030   }
01031 
01032   if (src == *src_head) {
01033     /* If we are moving the front of a train then we are, in effect, creating
01034      * a new head for the train. Point to that. Unless we are moving the whole
01035      * train in which case there is not 'source' train anymore.
01036      * In case we are a multiheaded part we want the complete thing to come
01037      * with us, so src->GetNextUnit(), however... when we are e.g. a wagon
01038      * that is followed by a rear multihead we do not want to include that. */
01039     *src_head = move_chain ? NULL :
01040         (src->IsMultiheaded() ? src->GetNextUnit() : src->GetNextVehicle());
01041   }
01042 
01043   /* Now it's just simply removing the part that we are going to move from the
01044    * source train and *if* the destination is a not a new train add the chain
01045    * at the destination location. */
01046   RemoveFromConsist(src, move_chain);
01047   if (*dst_head != src) InsertInConsist(dst, src);
01048 
01049   /* Now normalise the dual heads, that is move the dual heads around in such
01050    * a way that the head and rear of a dual head are in the same train */
01051   NormaliseDualHeads(*src_head);
01052   NormaliseDualHeads(*dst_head);
01053 }
01054 
01060 static void NormaliseTrainHead(Train *head)
01061 {
01062   /* Not much to do! */
01063   if (head == NULL) return;
01064 
01065   /* Tell the 'world' the train changed. */
01066   head->ConsistChanged(false);
01067   UpdateTrainGroupID(head);
01068 
01069   /* Not a front engine, i.e. a free wagon chain. No need to do more. */
01070   if (!head->IsFrontEngine()) return;
01071 
01072   /* Update the refit button and window */
01073   InvalidateWindowData(WC_VEHICLE_REFIT, head->index);
01074   SetWindowWidgetDirty(WC_VEHICLE_VIEW, head->index, WID_VV_REFIT);
01075 
01076   /* If we don't have a unit number yet, set one. */
01077   if (head->unitnumber != 0) return;
01078   head->unitnumber = GetFreeUnitNumber(VEH_TRAIN);
01079 }
01080 
01093 CommandCost CmdMoveRailVehicle(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
01094 {
01095   VehicleID s = GB(p1, 0, 20);
01096   VehicleID d = GB(p2, 0, 20);
01097   bool move_chain = HasBit(p1, 20);
01098 
01099   Train *src = Train::GetIfValid(s);
01100   if (src == NULL) return CMD_ERROR;
01101 
01102   CommandCost ret = CheckOwnership(src->owner);
01103   if (ret.Failed()) return ret;
01104 
01105   /* Do not allow moving crashed vehicles inside the depot, it is likely to cause asserts later */
01106   if (src->vehstatus & VS_CRASHED) return CMD_ERROR;
01107 
01108   /* if nothing is selected as destination, try and find a matching vehicle to drag to. */
01109   Train *dst;
01110   if (d == INVALID_VEHICLE) {
01111     dst = src->IsEngine() ? NULL : FindGoodVehiclePos(src);
01112   } else {
01113     dst = Train::GetIfValid(d);
01114     if (dst == NULL) return CMD_ERROR;
01115 
01116     CommandCost ret = CheckOwnership(dst->owner);
01117     if (ret.Failed()) return ret;
01118 
01119     /* Do not allow appending to crashed vehicles, too */
01120     if (dst->vehstatus & VS_CRASHED) return CMD_ERROR;
01121   }
01122 
01123   /* if an articulated part is being handled, deal with its parent vehicle */
01124   src = src->GetFirstEnginePart();
01125   if (dst != NULL) {
01126     dst = dst->GetFirstEnginePart();
01127   }
01128 
01129   /* don't move the same vehicle.. */
01130   if (src == dst) return CommandCost();
01131 
01132   /* locate the head of the two chains */
01133   Train *src_head = src->First();
01134   Train *dst_head;
01135   if (dst != NULL) {
01136     dst_head = dst->First();
01137     if (dst_head->tile != src_head->tile) return CMD_ERROR;
01138     /* Now deal with articulated part of destination wagon */
01139     dst = dst->GetLastEnginePart();
01140   } else {
01141     dst_head = NULL;
01142   }
01143 
01144   if (src->IsRearDualheaded()) return_cmd_error(STR_ERROR_REAR_ENGINE_FOLLOW_FRONT);
01145 
01146   /* When moving all wagons, we can't have the same src_head and dst_head */
01147   if (move_chain && src_head == dst_head) return CommandCost();
01148 
01149   /* When moving a multiheaded part to be place after itself, bail out. */
01150   if (!move_chain && dst != NULL && dst->IsRearDualheaded() && src == dst->other_multiheaded_part) return CommandCost();
01151 
01152   /* Check if all vehicles in the source train are stopped inside a depot. */
01153   if (!src_head->IsStoppedInDepot()) return_cmd_error(STR_ERROR_TRAINS_CAN_ONLY_BE_ALTERED_INSIDE_A_DEPOT);
01154 
01155   /* Check if all vehicles in the destination train are stopped inside a depot. */
01156   if (dst_head != NULL && !dst_head->IsStoppedInDepot()) return_cmd_error(STR_ERROR_TRAINS_CAN_ONLY_BE_ALTERED_INSIDE_A_DEPOT);
01157 
01158   /* First make a backup of the order of the trains. That way we can do
01159    * whatever we want with the order and later on easily revert. */
01160   TrainList original_src;
01161   TrainList original_dst;
01162 
01163   MakeTrainBackup(original_src, src_head);
01164   MakeTrainBackup(original_dst, dst_head);
01165 
01166   /* Also make backup of the original heads as ArrangeTrains can change them.
01167    * For the destination head we do not care if it is the same as the source
01168    * head because in that case it's just a copy. */
01169   Train *original_src_head = src_head;
01170   Train *original_dst_head = (dst_head == src_head ? NULL : dst_head);
01171 
01172   /* We want this information from before the rearrangement, but execute this after the validation. */
01173   bool original_src_head_front_engine = original_src_head != NULL && original_src_head->IsFrontEngine();
01174   bool original_dst_head_front_engine = original_dst_head != NULL && original_dst_head->IsFrontEngine();
01175 
01176   /* (Re)arrange the trains in the wanted arrangement. */
01177   ArrangeTrains(&dst_head, dst, &src_head, src, move_chain);
01178 
01179   if ((flags & DC_AUTOREPLACE) == 0) {
01180     /* If the autoreplace flag is set we do not need to test for the validity
01181      * because we are going to revert the train to its original state. As we
01182      * assume the original state was correct autoreplace can skip this. */
01183     CommandCost ret = ValidateTrains(original_dst_head, dst_head, original_src_head, src_head, true);
01184     if (ret.Failed()) {
01185       /* Restore the train we had. */
01186       RestoreTrainBackup(original_src);
01187       RestoreTrainBackup(original_dst);
01188       return ret;
01189     }
01190   }
01191 
01192   /* do it? */
01193   if (flags & DC_EXEC) {
01194     /* Remove old heads from the statistics */
01195     if (original_src_head_front_engine) GroupStatistics::CountVehicle(original_src_head, -1);
01196     if (original_dst_head_front_engine) GroupStatistics::CountVehicle(original_dst_head, -1);
01197 
01198     /* First normalise the sub types of the chains. */
01199     NormaliseSubtypes(src_head);
01200     NormaliseSubtypes(dst_head);
01201 
01202     /* There are 14 different cases:
01203      *  1) front engine gets moved to a new train, it stays a front engine.
01204      *     a) the 'next' part is a wagon that becomes a free wagon chain.
01205      *     b) the 'next' part is an engine that becomes a front engine.
01206      *     c) there is no 'next' part, nothing else happens
01207      *  2) front engine gets moved to another train, it is not a front engine anymore
01208      *     a) the 'next' part is a wagon that becomes a free wagon chain.
01209      *     b) the 'next' part is an engine that becomes a front engine.
01210      *     c) there is no 'next' part, nothing else happens
01211      *  3) front engine gets moved to later in the current train, it is not a front engine anymore.
01212      *     a) the 'next' part is a wagon that becomes a free wagon chain.
01213      *     b) the 'next' part is an engine that becomes a front engine.
01214      *  4) free wagon gets moved
01215      *     a) the 'next' part is a wagon that becomes a free wagon chain.
01216      *     b) the 'next' part is an engine that becomes a front engine.
01217      *     c) there is no 'next' part, nothing else happens
01218      *  5) non front engine gets moved and becomes a new train, nothing else happens
01219      *  6) non front engine gets moved within a train / to another train, nothing hapens
01220      *  7) wagon gets moved, nothing happens
01221      */
01222     if (src == original_src_head && src->IsEngine() && !src->IsFrontEngine()) {
01223       /* Cases #2 and #3: the front engine gets trashed. */
01224       DeleteWindowById(WC_VEHICLE_VIEW, src->index);
01225       DeleteWindowById(WC_VEHICLE_ORDERS, src->index);
01226       DeleteWindowById(WC_VEHICLE_REFIT, src->index);
01227       DeleteWindowById(WC_VEHICLE_DETAILS, src->index);
01228       DeleteWindowById(WC_VEHICLE_TIMETABLE, src->index);
01229       SetWindowDirty(WC_COMPANY, _current_company);
01230 
01231       /* Delete orders, group stuff and the unit number as we're not the
01232        * front of any vehicle anymore. */
01233       DeleteVehicleOrders(src);
01234       RemoveVehicleFromGroup(src);
01235       src->unitnumber = 0;
01236     }
01237 
01238     /* We weren't a front engine but are becoming one. So
01239      * we should be put in the default group. */
01240     if (original_src_head != src && dst_head == src) {
01241       SetTrainGroupID(src, DEFAULT_GROUP);
01242       SetWindowDirty(WC_COMPANY, _current_company);
01243     }
01244 
01245     /* Add new heads to statistics */
01246     if (src_head != NULL && src_head->IsFrontEngine()) GroupStatistics::CountVehicle(src_head, 1);
01247     if (dst_head != NULL && dst_head->IsFrontEngine()) GroupStatistics::CountVehicle(dst_head, 1);
01248 
01249     /* Handle 'new engine' part of cases #1b, #2b, #3b, #4b and #5 in NormaliseTrainHead. */
01250     NormaliseTrainHead(src_head);
01251     NormaliseTrainHead(dst_head);
01252 
01253     if ((flags & DC_NO_CARGO_CAP_CHECK) == 0) {
01254       CheckCargoCapacity(src_head);
01255       CheckCargoCapacity(dst_head);
01256     }
01257 
01258     /* We are undoubtedly changing something in the depot and train list. */
01259     InvalidateWindowData(WC_VEHICLE_DEPOT, src->tile);
01260     InvalidateWindowClassesData(WC_TRAINS_LIST, 0);
01261   } else {
01262     /* We don't want to execute what we're just tried. */
01263     RestoreTrainBackup(original_src);
01264     RestoreTrainBackup(original_dst);
01265   }
01266 
01267   return CommandCost();
01268 }
01269 
01281 CommandCost CmdSellRailWagon(DoCommandFlag flags, Vehicle *t, uint16 data, uint32 user)
01282 {
01283   /* Check if we deleted a vehicle window */
01284   Window *w = NULL;
01285 
01286   /* Sell a chain of vehicles or not? */
01287   bool sell_chain = HasBit(data, 0);
01288 
01289   Train *v = Train::From(t)->GetFirstEnginePart();
01290   Train *first = v->First();
01291 
01292   if (v->IsRearDualheaded()) return_cmd_error(STR_ERROR_REAR_ENGINE_FOLLOW_FRONT);
01293 
01294   /* First make a backup of the order of the train. That way we can do
01295    * whatever we want with the order and later on easily revert. */
01296   TrainList original;
01297   MakeTrainBackup(original, first);
01298 
01299   /* We need to keep track of the new head and the head of what we're going to sell. */
01300   Train *new_head = first;
01301   Train *sell_head = NULL;
01302 
01303   /* Split the train in the wanted way. */
01304   ArrangeTrains(&sell_head, NULL, &new_head, v, sell_chain);
01305 
01306   /* We don't need to validate the second train; it's going to be sold. */
01307   CommandCost ret = ValidateTrains(NULL, NULL, first, new_head, (flags & DC_AUTOREPLACE) == 0);
01308   if (ret.Failed()) {
01309     /* Restore the train we had. */
01310     RestoreTrainBackup(original);
01311     return ret;
01312   }
01313 
01314   CommandCost cost(EXPENSES_NEW_VEHICLES);
01315   for (Train *t = sell_head; t != NULL; t = t->Next()) cost.AddCost(-t->value);
01316 
01317   if (first->orders.list == NULL && !OrderList::CanAllocateItem()) {
01318     return_cmd_error(STR_ERROR_NO_MORE_SPACE_FOR_ORDERS);
01319   }
01320 
01321   /* do it? */
01322   if (flags & DC_EXEC) {
01323     /* First normalise the sub types of the chain. */
01324     NormaliseSubtypes(new_head);
01325 
01326     if (v == first && v->IsEngine() && !sell_chain && new_head != NULL && new_head->IsFrontEngine()) {
01327       /* We are selling the front engine. In this case we want to
01328        * 'give' the order, unit number and such to the new head. */
01329       new_head->orders.list = first->orders.list;
01330       new_head->AddToShared(first);
01331       DeleteVehicleOrders(first);
01332 
01333       /* Copy other important data from the front engine */
01334       new_head->CopyVehicleConfigAndStatistics(first);
01335       GroupStatistics::CountVehicle(new_head, 1); // after copying over the profit
01336 
01337       /* If we deleted a window then open a new one for the 'new' train */
01338       if (IsLocalCompany() && w != NULL) ShowVehicleViewWindow(new_head);
01339     } else if (v->IsPrimaryVehicle() && data & (MAKE_ORDER_BACKUP_FLAG >> 20)) {
01340       OrderBackup::Backup(v, user);
01341     }
01342 
01343     /* We need to update the information about the train. */
01344     NormaliseTrainHead(new_head);
01345 
01346     /* We are undoubtedly changing something in the depot and train list. */
01347     InvalidateWindowData(WC_VEHICLE_DEPOT, v->tile);
01348     InvalidateWindowClassesData(WC_TRAINS_LIST, 0);
01349 
01350     /* Actually delete the sold 'goods' */
01351     delete sell_head;
01352   } else {
01353     /* We don't want to execute what we're just tried. */
01354     RestoreTrainBackup(original);
01355   }
01356 
01357   return cost;
01358 }
01359 
01360 void Train::UpdateDeltaXY(Direction direction)
01361 {
01362   /* Set common defaults. */
01363   this->x_offs    = -1;
01364   this->y_offs    = -1;
01365   this->x_extent  =  3;
01366   this->y_extent  =  3;
01367   this->z_extent  =  6;
01368   this->x_bb_offs =  0;
01369   this->y_bb_offs =  0;
01370 
01371   if (!IsDiagonalDirection(direction)) {
01372     static const int _sign_table[] =
01373     {
01374       // x, y
01375       -1, -1, // DIR_N
01376       -1,  1, // DIR_E
01377        1,  1, // DIR_S
01378        1, -1, // DIR_W
01379     };
01380 
01381     int half_shorten = (VEHICLE_LENGTH - this->gcache.cached_veh_length) / 2;
01382 
01383     /* For all straight directions, move the bound box to the centre of the vehicle, but keep the size. */
01384     this->x_offs -= half_shorten * _sign_table[direction];
01385     this->y_offs -= half_shorten * _sign_table[direction + 1];
01386     this->x_extent += this->x_bb_offs = half_shorten * _sign_table[direction];
01387     this->y_extent += this->y_bb_offs = half_shorten * _sign_table[direction + 1];
01388   } else {
01389     switch (direction) {
01390         /* Shorten southern corner of the bounding box according the vehicle length
01391          * and center the bounding box on the vehicle. */
01392       case DIR_NE:
01393         this->x_offs    = 1 - (this->gcache.cached_veh_length + 1) / 2;
01394         this->x_extent  = this->gcache.cached_veh_length - 1;
01395         this->x_bb_offs = -1;
01396         break;
01397 
01398       case DIR_NW:
01399         this->y_offs    = 1 - (this->gcache.cached_veh_length + 1) / 2;
01400         this->y_extent  = this->gcache.cached_veh_length - 1;
01401         this->y_bb_offs = -1;
01402         break;
01403 
01404         /* Move northern corner of the bounding box down according to vehicle length
01405          * and center the bounding box on the vehicle. */
01406       case DIR_SW:
01407         this->x_offs    = 1 + (this->gcache.cached_veh_length + 1) / 2 - VEHICLE_LENGTH;
01408         this->x_extent  = VEHICLE_LENGTH - 1;
01409         this->x_bb_offs = VEHICLE_LENGTH - this->gcache.cached_veh_length - 1;
01410         break;
01411 
01412       case DIR_SE:
01413         this->y_offs    = 1 + (this->gcache.cached_veh_length + 1) / 2 - VEHICLE_LENGTH;
01414         this->y_extent  = VEHICLE_LENGTH - 1;
01415         this->y_bb_offs = VEHICLE_LENGTH - this->gcache.cached_veh_length - 1;
01416         break;
01417 
01418       default:
01419         NOT_REACHED();
01420     }
01421   }
01422 }
01423 
01428 static void MarkTrainAsStuck(Train *v)
01429 {
01430   if (!HasBit(v->flags, VRF_TRAIN_STUCK)) {
01431     /* It is the first time the problem occurred, set the "train stuck" flag. */
01432     SetBit(v->flags, VRF_TRAIN_STUCK);
01433 
01434     v->wait_counter = 0;
01435 
01436     /* Stop train */
01437     v->cur_speed = 0;
01438     v->subspeed = 0;
01439     v->SetLastSpeed();
01440 
01441     SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
01442   }
01443 }
01444 
01452 static void SwapTrainFlags(uint16 *swap_flag1, uint16 *swap_flag2)
01453 {
01454   uint16 flag1 = *swap_flag1;
01455   uint16 flag2 = *swap_flag2;
01456 
01457   /* Clear the flags */
01458   ClrBit(*swap_flag1, GVF_GOINGUP_BIT);
01459   ClrBit(*swap_flag1, GVF_GOINGDOWN_BIT);
01460   ClrBit(*swap_flag2, GVF_GOINGUP_BIT);
01461   ClrBit(*swap_flag2, GVF_GOINGDOWN_BIT);
01462 
01463   /* Reverse the rail-flags (if needed) */
01464   if (HasBit(flag1, GVF_GOINGUP_BIT)) {
01465     SetBit(*swap_flag2, GVF_GOINGDOWN_BIT);
01466   } else if (HasBit(flag1, GVF_GOINGDOWN_BIT)) {
01467     SetBit(*swap_flag2, GVF_GOINGUP_BIT);
01468   }
01469   if (HasBit(flag2, GVF_GOINGUP_BIT)) {
01470     SetBit(*swap_flag1, GVF_GOINGDOWN_BIT);
01471   } else if (HasBit(flag2, GVF_GOINGDOWN_BIT)) {
01472     SetBit(*swap_flag1, GVF_GOINGUP_BIT);
01473   }
01474 }
01475 
01480 static void UpdateStatusAfterSwap(Train *v)
01481 {
01482   /* Reverse the direction. */
01483   if (v->track != TRACK_BIT_DEPOT) v->direction = ReverseDir(v->direction);
01484 
01485   /* Call the proper EnterTile function unless we are in a wormhole. */
01486   if (v->track != TRACK_BIT_WORMHOLE) {
01487     VehicleEnterTile(v, v->tile, v->x_pos, v->y_pos);
01488   } else {
01489     /* VehicleEnter_TunnelBridge() sets TRACK_BIT_WORMHOLE when the vehicle
01490      * is on the last bit of the bridge head (frame == TILE_SIZE - 1).
01491      * If we were swapped with such a vehicle, we have set TRACK_BIT_WORMHOLE,
01492      * when we shouldn't have. Check if this is the case. */
01493     TileIndex vt = TileVirtXY(v->x_pos, v->y_pos);
01494     if (IsTileType(vt, MP_TUNNELBRIDGE)) {
01495       VehicleEnterTile(v, vt, v->x_pos, v->y_pos);
01496       if (v->track != TRACK_BIT_WORMHOLE && IsBridgeTile(v->tile)) {
01497         /* We have just left the wormhole, possibly set the
01498          * "goingdown" bit. UpdateInclination() can be used
01499          * because we are at the border of the tile. */
01500         VehicleUpdatePosition(v);
01501         v->UpdateInclination(true, true);
01502         return;
01503       }
01504     }
01505   }
01506 
01507   VehicleUpdatePosition(v);
01508   v->UpdateViewport(true, true);
01509 }
01510 
01517 void ReverseTrainSwapVeh(Train *v, int l, int r)
01518 {
01519   Train *a, *b;
01520 
01521   /* locate vehicles to swap */
01522   for (a = v; l != 0; l--) a = a->Next();
01523   for (b = v; r != 0; r--) b = b->Next();
01524 
01525   if (a != b) {
01526     /* swap the hidden bits */
01527     {
01528       uint16 tmp = (a->vehstatus & ~VS_HIDDEN) | (b->vehstatus & VS_HIDDEN);
01529       b->vehstatus = (b->vehstatus & ~VS_HIDDEN) | (a->vehstatus & VS_HIDDEN);
01530       a->vehstatus = tmp;
01531     }
01532 
01533     Swap(a->track, b->track);
01534     Swap(a->direction, b->direction);
01535     Swap(a->x_pos, b->x_pos);
01536     Swap(a->y_pos, b->y_pos);
01537     Swap(a->tile,  b->tile);
01538     Swap(a->z_pos, b->z_pos);
01539 
01540     SwapTrainFlags(&a->gv_flags, &b->gv_flags);
01541 
01542     UpdateStatusAfterSwap(a);
01543     UpdateStatusAfterSwap(b);
01544   } else {
01545     /* Swap GVF_GOINGUP_BIT/GVF_GOINGDOWN_BIT.
01546      * This is a little bit redundant way, a->gv_flags will
01547      * be (re)set twice, but it reduces code duplication */
01548     SwapTrainFlags(&a->gv_flags, &a->gv_flags);
01549     UpdateStatusAfterSwap(a);
01550   }
01551 }
01552 
01553 
01559 static Vehicle *TrainOnTileEnum(Vehicle *v, void *)
01560 {
01561   return (v->type == VEH_TRAIN) ? v : NULL;
01562 }
01563 
01564 
01571 static Vehicle *TrainApproachingCrossingEnum(Vehicle *v, void *data)
01572 {
01573   if (v->type != VEH_TRAIN || (v->vehstatus & VS_CRASHED)) return NULL;
01574 
01575   Train *t = Train::From(v);
01576   if (!t->IsFrontEngine()) return NULL;
01577 
01578   TileIndex tile = *(TileIndex *)data;
01579 
01580   if (TrainApproachingCrossingTile(t) != tile) return NULL;
01581 
01582   return t;
01583 }
01584 
01585 
01592 static bool TrainApproachingCrossing(TileIndex tile)
01593 {
01594   assert(IsLevelCrossingTile(tile));
01595 
01596   DiagDirection dir = AxisToDiagDir(GetCrossingRailAxis(tile));
01597   TileIndex tile_from = tile + TileOffsByDiagDir(dir);
01598 
01599   if (HasVehicleOnPos(tile_from, &tile, &TrainApproachingCrossingEnum)) return true;
01600 
01601   dir = ReverseDiagDir(dir);
01602   tile_from = tile + TileOffsByDiagDir(dir);
01603 
01604   return HasVehicleOnPos(tile_from, &tile, &TrainApproachingCrossingEnum);
01605 }
01606 
01607 
01614 void UpdateLevelCrossing(TileIndex tile, bool sound)
01615 {
01616   assert(IsLevelCrossingTile(tile));
01617 
01618   /* train on crossing || train approaching crossing || reserved */
01619   bool new_state = HasVehicleOnPos(tile, NULL, &TrainOnTileEnum) || TrainApproachingCrossing(tile) || HasCrossingReservation(tile);
01620 
01621   if (new_state != IsCrossingBarred(tile)) {
01622     if (new_state && sound) {
01623       SndPlayTileFx(SND_0E_LEVEL_CROSSING, tile);
01624     }
01625     SetCrossingBarred(tile, new_state);
01626     MarkTileDirtyByTile(tile);
01627   }
01628 }
01629 
01630 
01636 static inline void MaybeBarCrossingWithSound(TileIndex tile)
01637 {
01638   if (!IsCrossingBarred(tile)) {
01639     BarCrossing(tile);
01640     SndPlayTileFx(SND_0E_LEVEL_CROSSING, tile);
01641     MarkTileDirtyByTile(tile);
01642   }
01643 }
01644 
01645 
01651 static void AdvanceWagonsBeforeSwap(Train *v)
01652 {
01653   Train *base = v;
01654   Train *first = base; // first vehicle to move
01655   Train *last = v->Last(); // last vehicle to move
01656   uint length = CountVehiclesInChain(v);
01657 
01658   while (length > 2) {
01659     last = last->Previous();
01660     first = first->Next();
01661 
01662     int differential = base->CalcNextVehicleOffset() - last->CalcNextVehicleOffset();
01663 
01664     /* do not update images now
01665      * negative differential will be handled in AdvanceWagonsAfterSwap() */
01666     for (int i = 0; i < differential; i++) TrainController(first, last->Next());
01667 
01668     base = first; // == base->Next()
01669     length -= 2;
01670   }
01671 }
01672 
01673 
01679 static void AdvanceWagonsAfterSwap(Train *v)
01680 {
01681   /* first of all, fix the situation when the train was entering a depot */
01682   Train *dep = v; // last vehicle in front of just left depot
01683   while (dep->Next() != NULL && (dep->track == TRACK_BIT_DEPOT || dep->Next()->track != TRACK_BIT_DEPOT)) {
01684     dep = dep->Next(); // find first vehicle outside of a depot, with next vehicle inside a depot
01685   }
01686 
01687   Train *leave = dep->Next(); // first vehicle in a depot we are leaving now
01688 
01689   if (leave != NULL) {
01690     /* 'pull' next wagon out of the depot, so we won't miss it (it could stay in depot forever) */
01691     int d = TicksToLeaveDepot(dep);
01692 
01693     if (d <= 0) {
01694       leave->vehstatus &= ~VS_HIDDEN; // move it out of the depot
01695       leave->track = TrackToTrackBits(GetRailDepotTrack(leave->tile));
01696       for (int i = 0; i >= d; i--) TrainController(leave, NULL); // maybe move it, and maybe let another wagon leave
01697     }
01698   } else {
01699     dep = NULL; // no vehicle in a depot, so no vehicle leaving a depot
01700   }
01701 
01702   Train *base = v;
01703   Train *first = base; // first vehicle to move
01704   Train *last = v->Last(); // last vehicle to move
01705   uint length = CountVehiclesInChain(v);
01706 
01707   /* We have to make sure all wagons that leave a depot because of train reversing are moved correctly
01708    * they have already correct spacing, so we have to make sure they are moved how they should */
01709   bool nomove = (dep == NULL); // If there is no vehicle leaving a depot, limit the number of wagons moved immediately.
01710 
01711   while (length > 2) {
01712     /* we reached vehicle (originally) in front of a depot, stop now
01713      * (we would move wagons that are already moved with new wagon length). */
01714     if (base == dep) break;
01715 
01716     /* the last wagon was that one leaving a depot, so do not move it anymore */
01717     if (last == dep) nomove = true;
01718 
01719     last = last->Previous();
01720     first = first->Next();
01721 
01722     int differential = last->CalcNextVehicleOffset() - base->CalcNextVehicleOffset();
01723 
01724     /* do not update images now */
01725     for (int i = 0; i < differential; i++) TrainController(first, (nomove ? last->Next() : NULL));
01726 
01727     base = first; // == base->Next()
01728     length -= 2;
01729   }
01730 }
01731 
01736 void ReverseTrainDirection(Train *v)
01737 {
01738   if (IsRailDepotTile(v->tile)) {
01739     InvalidateWindowData(WC_VEHICLE_DEPOT, v->tile);
01740   }
01741 
01742   /* Clear path reservation in front if train is not stuck. */
01743   if (!HasBit(v->flags, VRF_TRAIN_STUCK)) FreeTrainTrackReservation(v);
01744 
01745   /* Check if we were approaching a rail/road-crossing */
01746   TileIndex crossing = TrainApproachingCrossingTile(v);
01747 
01748   /* count number of vehicles */
01749   int r = CountVehiclesInChain(v) - 1;  // number of vehicles - 1
01750 
01751   AdvanceWagonsBeforeSwap(v);
01752 
01753   /* swap start<>end, start+1<>end-1, ... */
01754   int l = 0;
01755   do {
01756     ReverseTrainSwapVeh(v, l++, r--);
01757   } while (l <= r);
01758 
01759   AdvanceWagonsAfterSwap(v);
01760 
01761   if (IsRailDepotTile(v->tile)) {
01762     InvalidateWindowData(WC_VEHICLE_DEPOT, v->tile);
01763   }
01764 
01765   ToggleBit(v->flags, VRF_TOGGLE_REVERSE);
01766 
01767   ClrBit(v->flags, VRF_REVERSING);
01768 
01769   /* recalculate cached data */
01770   v->ConsistChanged(true);
01771 
01772   /* update all images */
01773   for (Train *u = v; u != NULL; u = u->Next()) u->UpdateViewport(false, false);
01774 
01775   /* update crossing we were approaching */
01776   if (crossing != INVALID_TILE) UpdateLevelCrossing(crossing);
01777 
01778   /* maybe we are approaching crossing now, after reversal */
01779   crossing = TrainApproachingCrossingTile(v);
01780   if (crossing != INVALID_TILE) MaybeBarCrossingWithSound(crossing);
01781 
01782   /* If we are inside a depot after reversing, don't bother with path reserving. */
01783   if (v->track == TRACK_BIT_DEPOT) {
01784     /* Can't be stuck here as inside a depot is always a safe tile. */
01785     if (HasBit(v->flags, VRF_TRAIN_STUCK)) SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
01786     ClrBit(v->flags, VRF_TRAIN_STUCK);
01787     return;
01788   }
01789 
01790   /* TrainExitDir does not always produce the desired dir for depots and
01791    * tunnels/bridges that is needed for UpdateSignalsOnSegment. */
01792   DiagDirection dir = TrainExitDir(v->direction, v->track);
01793   if (IsRailDepotTile(v->tile) || IsTileType(v->tile, MP_TUNNELBRIDGE)) dir = INVALID_DIAGDIR;
01794 
01795   if (UpdateSignalsOnSegment(v->tile, dir, v->owner) == SIGSEG_PBS || _settings_game.pf.reserve_paths) {
01796     /* If we are currently on a tile with conventional signals, we can't treat the
01797      * current tile as a safe tile or we would enter a PBS block without a reservation. */
01798     bool first_tile_okay = !(IsTileType(v->tile, MP_RAILWAY) &&
01799       HasSignalOnTrackdir(v->tile, v->GetVehicleTrackdir()) &&
01800       !IsPbsSignal(GetSignalType(v->tile, FindFirstTrack(v->track))));
01801 
01802     /* If we are on a depot tile facing outwards, do not treat the current tile as safe. */
01803     if (IsRailDepotTile(v->tile) && TrackdirToExitdir(v->GetVehicleTrackdir()) == GetRailDepotDirection(v->tile)) first_tile_okay = false;
01804 
01805     if (IsRailStationTile(v->tile)) SetRailStationPlatformReservation(v->tile, TrackdirToExitdir(v->GetVehicleTrackdir()), true);
01806     if (TryPathReserve(v, false, first_tile_okay)) {
01807       /* Do a look-ahead now in case our current tile was already a safe tile. */
01808       CheckNextTrainTile(v);
01809     } else if (v->current_order.GetType() != OT_LOADING) {
01810       /* Do not wait for a way out when we're still loading */
01811       MarkTrainAsStuck(v);
01812     }
01813   } else if (HasBit(v->flags, VRF_TRAIN_STUCK)) {
01814     /* A train not inside a PBS block can't be stuck. */
01815     ClrBit(v->flags, VRF_TRAIN_STUCK);
01816     v->wait_counter = 0;
01817   }
01818 }
01819 
01829 CommandCost CmdReverseTrainDirection(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
01830 {
01831   Train *v = Train::GetIfValid(p1);
01832   if (v == NULL) return CMD_ERROR;
01833 
01834   CommandCost ret = CheckOwnership(v->owner);
01835   if (ret.Failed()) return ret;
01836 
01837   if (p2 != 0) {
01838     /* turn a single unit around */
01839 
01840     if (v->IsMultiheaded() || HasBit(EngInfo(v->engine_type)->callback_mask, CBM_VEHICLE_ARTIC_ENGINE)) {
01841       return_cmd_error(STR_ERROR_CAN_T_REVERSE_DIRECTION_RAIL_VEHICLE_MULTIPLE_UNITS);
01842     }
01843     if (!HasBit(EngInfo(v->engine_type)->misc_flags, EF_RAIL_FLIPS)) return CMD_ERROR;
01844 
01845     Train *front = v->First();
01846     /* make sure the vehicle is stopped in the depot */
01847     if (!front->IsStoppedInDepot()) {
01848       return_cmd_error(STR_ERROR_TRAINS_CAN_ONLY_BE_ALTERED_INSIDE_A_DEPOT);
01849     }
01850 
01851     if (flags & DC_EXEC) {
01852       ToggleBit(v->flags, VRF_REVERSE_DIRECTION);
01853 
01854       front->ConsistChanged(false);
01855       SetWindowDirty(WC_VEHICLE_DEPOT, front->tile);
01856       SetWindowDirty(WC_VEHICLE_DETAILS, front->index);
01857       SetWindowDirty(WC_VEHICLE_VIEW, front->index);
01858       SetWindowClassesDirty(WC_TRAINS_LIST);
01859     }
01860   } else {
01861     /* turn the whole train around */
01862     if ((v->vehstatus & VS_CRASHED) || v->breakdown_ctr != 0) return CMD_ERROR;
01863 
01864     if (flags & DC_EXEC) {
01865       /* Properly leave the station if we are loading and won't be loading anymore */
01866       if (v->current_order.IsType(OT_LOADING)) {
01867         const Vehicle *last = v;
01868         while (last->Next() != NULL) last = last->Next();
01869 
01870         /* not a station || different station --> leave the station */
01871         if (!IsTileType(last->tile, MP_STATION) || GetStationIndex(last->tile) != GetStationIndex(v->tile)) {
01872           v->LeaveStation();
01873         }
01874       }
01875 
01876       /* We cancel any 'skip signal at dangers' here */
01877       v->force_proceed = TFP_NONE;
01878       SetWindowDirty(WC_VEHICLE_VIEW, v->index);
01879 
01880       if (_settings_game.vehicle.train_acceleration_model != AM_ORIGINAL && v->cur_speed != 0) {
01881         ToggleBit(v->flags, VRF_REVERSING);
01882       } else {
01883         v->cur_speed = 0;
01884         v->SetLastSpeed();
01885         HideFillingPercent(&v->fill_percent_te_id);
01886         ReverseTrainDirection(v);
01887       }
01888     }
01889   }
01890   return CommandCost();
01891 }
01892 
01902 CommandCost CmdForceTrainProceed(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
01903 {
01904   Train *t = Train::GetIfValid(p1);
01905   if (t == NULL) return CMD_ERROR;
01906 
01907   if (!t->IsPrimaryVehicle()) return CMD_ERROR;
01908 
01909   CommandCost ret = CheckOwnership(t->owner);
01910   if (ret.Failed()) return ret;
01911 
01912 
01913   if (flags & DC_EXEC) {
01914     /* If we are forced to proceed, cancel that order.
01915      * If we are marked stuck we would want to force the train
01916      * to proceed to the next signal. In the other cases we
01917      * would like to pass the signal at danger and run till the
01918      * next signal we encounter. */
01919     t->force_proceed = t->force_proceed == TFP_SIGNAL ? TFP_NONE : HasBit(t->flags, VRF_TRAIN_STUCK) || t->IsChainInDepot() ? TFP_STUCK : TFP_SIGNAL;
01920     SetWindowDirty(WC_VEHICLE_VIEW, t->index);
01921   }
01922 
01923   return CommandCost();
01924 }
01925 
01933 static FindDepotData FindClosestTrainDepot(Train *v, int max_distance)
01934 {
01935   assert(!(v->vehstatus & VS_CRASHED));
01936 
01937   if (IsRailDepotTile(v->tile)) return FindDepotData(v->tile, 0);
01938 
01939   PBSTileInfo origin = FollowTrainReservation(v);
01940   if (IsRailDepotTile(origin.tile)) return FindDepotData(origin.tile, 0);
01941 
01942   switch (_settings_game.pf.pathfinder_for_trains) {
01943     case VPF_NPF: return NPFTrainFindNearestDepot(v, max_distance);
01944     case VPF_YAPF: return YapfTrainFindNearestDepot(v, max_distance);
01945 
01946     default: NOT_REACHED();
01947   }
01948 }
01949 
01957 bool Train::FindClosestDepot(TileIndex *location, DestinationID *destination, bool *reverse)
01958 {
01959   FindDepotData tfdd = FindClosestTrainDepot(this, 0);
01960   if (tfdd.best_length == UINT_MAX) return false;
01961 
01962   if (location    != NULL) *location    = tfdd.tile;
01963   if (destination != NULL) *destination = GetDepotIndex(tfdd.tile);
01964   if (reverse     != NULL) *reverse     = tfdd.reverse;
01965 
01966   return true;
01967 }
01968 
01970 void Train::PlayLeaveStationSound() const
01971 {
01972   static const SoundFx sfx[] = {
01973     SND_04_TRAIN,
01974     SND_0A_TRAIN_HORN,
01975     SND_0A_TRAIN_HORN,
01976     SND_47_MAGLEV_2,
01977     SND_41_MAGLEV
01978   };
01979 
01980   if (PlayVehicleSound(this, VSE_START)) return;
01981 
01982   EngineID engtype = this->engine_type;
01983   SndPlayVehicleFx(sfx[RailVehInfo(engtype)->engclass], this);
01984 }
01985 
01990 static void CheckNextTrainTile(Train *v)
01991 {
01992   /* Don't do any look-ahead if path_backoff_interval is 255. */
01993   if (_settings_game.pf.path_backoff_interval == 255) return;
01994 
01995   /* Exit if we are inside a depot. */
01996   if (v->track == TRACK_BIT_DEPOT) return;
01997 
01998   switch (v->current_order.GetType()) {
01999     /* Exit if we reached our destination depot. */
02000     case OT_GOTO_DEPOT:
02001       if (v->tile == v->dest_tile) return;
02002       break;
02003 
02004     case OT_GOTO_WAYPOINT:
02005       /* If we reached our waypoint, make sure we see that. */
02006       if (IsRailWaypointTile(v->tile) && GetStationIndex(v->tile) == v->current_order.GetDestination()) ProcessOrders(v);
02007       break;
02008 
02009     case OT_NOTHING:
02010     case OT_LEAVESTATION:
02011     case OT_LOADING:
02012       /* Exit if the current order doesn't have a destination, but the train has orders. */
02013       if (v->GetNumOrders() > 0) return;
02014       break;
02015 
02016     default:
02017       break;
02018   }
02019   /* Exit if we are on a station tile and are going to stop. */
02020   if (IsRailStationTile(v->tile) && v->current_order.ShouldStopAtStation(v, GetStationIndex(v->tile))) return;
02021 
02022   Trackdir td = v->GetVehicleTrackdir();
02023 
02024   /* On a tile with a red non-pbs signal, don't look ahead. */
02025   if (IsTileType(v->tile, MP_RAILWAY) && HasSignalOnTrackdir(v->tile, td) &&
02026       !IsPbsSignal(GetSignalType(v->tile, TrackdirToTrack(td))) &&
02027       GetSignalStateByTrackdir(v->tile, td) == SIGNAL_STATE_RED) return;
02028 
02029   CFollowTrackRail ft(v);
02030   if (!ft.Follow(v->tile, td)) return;
02031 
02032   if (!HasReservedTracks(ft.m_new_tile, TrackdirBitsToTrackBits(ft.m_new_td_bits))) {
02033     /* Next tile is not reserved. */
02034     if (KillFirstBit(ft.m_new_td_bits) == TRACKDIR_BIT_NONE) {
02035       if (HasPbsSignalOnTrackdir(ft.m_new_tile, FindFirstTrackdir(ft.m_new_td_bits))) {
02036         /* If the next tile is a PBS signal, try to make a reservation. */
02037         TrackBits tracks = TrackdirBitsToTrackBits(ft.m_new_td_bits);
02038         if (_settings_game.pf.forbid_90_deg) {
02039           tracks &= ~TrackCrossesTracks(TrackdirToTrack(ft.m_old_td));
02040         }
02041         ChooseTrainTrack(v, ft.m_new_tile, ft.m_exitdir, tracks, false, NULL, false);
02042       }
02043     }
02044   }
02045 }
02046 
02052 static bool CheckTrainStayInDepot(Train *v)
02053 {
02054   /* bail out if not all wagons are in the same depot or not in a depot at all */
02055   for (const Train *u = v; u != NULL; u = u->Next()) {
02056     if (u->track != TRACK_BIT_DEPOT || u->tile != v->tile) return false;
02057   }
02058 
02059   /* if the train got no power, then keep it in the depot */
02060   if (v->gcache.cached_power == 0) {
02061     v->vehstatus |= VS_STOPPED;
02062     SetWindowDirty(WC_VEHICLE_DEPOT, v->tile);
02063     return true;
02064   }
02065 
02066   SigSegState seg_state;
02067 
02068   if (v->force_proceed == TFP_NONE) {
02069     /* force proceed was not pressed */
02070     if (++v->wait_counter < 37) {
02071       SetWindowClassesDirty(WC_TRAINS_LIST);
02072       return true;
02073     }
02074 
02075     v->wait_counter = 0;
02076 
02077     seg_state = _settings_game.pf.reserve_paths ? SIGSEG_PBS : UpdateSignalsOnSegment(v->tile, INVALID_DIAGDIR, v->owner);
02078     if (seg_state == SIGSEG_FULL || HasDepotReservation(v->tile)) {
02079       /* Full and no PBS signal in block or depot reserved, can't exit. */
02080       SetWindowClassesDirty(WC_TRAINS_LIST);
02081       return true;
02082     }
02083   } else {
02084     seg_state = _settings_game.pf.reserve_paths ? SIGSEG_PBS : UpdateSignalsOnSegment(v->tile, INVALID_DIAGDIR, v->owner);
02085   }
02086 
02087   /* We are leaving a depot, but have to go to the exact same one; re-enter */
02088   if (v->current_order.IsType(OT_GOTO_DEPOT) && v->tile == v->dest_tile) {
02089     /* We need to have a reservation for this to work. */
02090     if (HasDepotReservation(v->tile)) return true;
02091     SetDepotReservation(v->tile, true);
02092     VehicleEnterDepot(v);
02093     return true;
02094   }
02095 
02096   /* Only leave when we can reserve a path to our destination. */
02097   if (seg_state == SIGSEG_PBS && !TryPathReserve(v) && v->force_proceed == TFP_NONE) {
02098     /* No path and no force proceed. */
02099     SetWindowClassesDirty(WC_TRAINS_LIST);
02100     MarkTrainAsStuck(v);
02101     return true;
02102   }
02103 
02104   SetDepotReservation(v->tile, true);
02105   if (_settings_client.gui.show_track_reservation) MarkTileDirtyByTile(v->tile);
02106 
02107   VehicleServiceInDepot(v);
02108   SetWindowClassesDirty(WC_TRAINS_LIST);
02109   v->PlayLeaveStationSound();
02110 
02111   v->track = TRACK_BIT_X;
02112   if (v->direction & 2) v->track = TRACK_BIT_Y;
02113 
02114   v->vehstatus &= ~VS_HIDDEN;
02115   v->cur_speed = 0;
02116 
02117   v->UpdateViewport(true, true);
02118   VehicleUpdatePosition(v);
02119   UpdateSignalsOnSegment(v->tile, INVALID_DIAGDIR, v->owner);
02120   v->UpdateAcceleration();
02121   InvalidateWindowData(WC_VEHICLE_DEPOT, v->tile);
02122 
02123   return false;
02124 }
02125 
02132 static void ClearPathReservation(const Train *v, TileIndex tile, Trackdir track_dir)
02133 {
02134   DiagDirection dir = TrackdirToExitdir(track_dir);
02135 
02136   if (IsTileType(tile, MP_TUNNELBRIDGE)) {
02137     /* Are we just leaving a tunnel/bridge? */
02138     if (GetTunnelBridgeDirection(tile) == ReverseDiagDir(dir)) {
02139       TileIndex end = GetOtherTunnelBridgeEnd(tile);
02140 
02141       if (TunnelBridgeIsFree(tile, end, v).Succeeded()) {
02142         /* Free the reservation only if no other train is on the tiles. */
02143         SetTunnelBridgeReservation(tile, false);
02144         SetTunnelBridgeReservation(end, false);
02145 
02146         if (_settings_client.gui.show_track_reservation) {
02147           MarkTileDirtyByTile(tile);
02148           MarkTileDirtyByTile(end);
02149         }
02150       }
02151     }
02152   } else if (IsRailStationTile(tile)) {
02153     TileIndex new_tile = TileAddByDiagDir(tile, dir);
02154     /* If the new tile is not a further tile of the same station, we
02155      * clear the reservation for the whole platform. */
02156     if (!IsCompatibleTrainStationTile(new_tile, tile)) {
02157       SetRailStationPlatformReservation(tile, ReverseDiagDir(dir), false);
02158     }
02159   } else {
02160     /* Any other tile */
02161     UnreserveRailTrack(tile, TrackdirToTrack(track_dir));
02162   }
02163 }
02164 
02171 void FreeTrainTrackReservation(const Train *v, TileIndex origin, Trackdir orig_td)
02172 {
02173   assert(v->IsFrontEngine());
02174 
02175   TileIndex tile = origin != INVALID_TILE ? origin : v->tile;
02176   Trackdir  td = orig_td != INVALID_TRACKDIR ? orig_td : v->GetVehicleTrackdir();
02177   bool      free_tile = tile != v->tile || !(IsRailStationTile(v->tile) || IsTileType(v->tile, MP_TUNNELBRIDGE));
02178   StationID station_id = IsRailStationTile(v->tile) ? GetStationIndex(v->tile) : INVALID_STATION;
02179 
02180   /* Can't be holding a reservation if we enter a depot. */
02181   if (IsRailDepotTile(tile) && TrackdirToExitdir(td) != GetRailDepotDirection(tile)) return;
02182   if (v->track == TRACK_BIT_DEPOT) {
02183     /* Front engine is in a depot. We enter if some part is not in the depot. */
02184     for (const Train *u = v; u != NULL; u = u->Next()) {
02185       if (u->track != TRACK_BIT_DEPOT || u->tile != v->tile) return;
02186     }
02187   }
02188   /* Don't free reservation if it's not ours. */
02189   if (TracksOverlap(GetReservedTrackbits(tile) | TrackToTrackBits(TrackdirToTrack(td)))) return;
02190 
02191   CFollowTrackRail ft(v, GetRailTypeInfo(v->railtype)->compatible_railtypes);
02192   while (ft.Follow(tile, td)) {
02193     tile = ft.m_new_tile;
02194     TrackdirBits bits = ft.m_new_td_bits & TrackBitsToTrackdirBits(GetReservedTrackbits(tile));
02195     td = RemoveFirstTrackdir(&bits);
02196     assert(bits == TRACKDIR_BIT_NONE);
02197 
02198     if (!IsValidTrackdir(td)) break;
02199 
02200     if (IsTileType(tile, MP_RAILWAY)) {
02201       if (HasSignalOnTrackdir(tile, td) && !IsPbsSignal(GetSignalType(tile, TrackdirToTrack(td)))) {
02202         /* Conventional signal along trackdir: remove reservation and stop. */
02203         UnreserveRailTrack(tile, TrackdirToTrack(td));
02204         break;
02205       }
02206       if (HasPbsSignalOnTrackdir(tile, td)) {
02207         if (GetSignalStateByTrackdir(tile, td) == SIGNAL_STATE_RED) {
02208           /* Red PBS signal? Can't be our reservation, would be green then. */
02209           break;
02210         } else {
02211           /* Turn the signal back to red. */
02212           SetSignalStateByTrackdir(tile, td, SIGNAL_STATE_RED);
02213           MarkTileDirtyByTile(tile);
02214         }
02215       } else if (HasSignalOnTrackdir(tile, ReverseTrackdir(td)) && IsOnewaySignal(tile, TrackdirToTrack(td))) {
02216         break;
02217       }
02218     }
02219 
02220     /* Don't free first station/bridge/tunnel if we are on it. */
02221     if (free_tile || (!(ft.m_is_station && GetStationIndex(ft.m_new_tile) == station_id) && !ft.m_is_tunnel && !ft.m_is_bridge)) ClearPathReservation(v, tile, td);
02222 
02223     free_tile = true;
02224   }
02225 }
02226 
02227 static const byte _initial_tile_subcoord[6][4][3] = {
02228 {{ 15, 8, 1 }, { 0, 0, 0 }, { 0, 8, 5 }, { 0,  0, 0 }},
02229 {{  0, 0, 0 }, { 8, 0, 3 }, { 0, 0, 0 }, { 8, 15, 7 }},
02230 {{  0, 0, 0 }, { 7, 0, 2 }, { 0, 7, 6 }, { 0,  0, 0 }},
02231 {{ 15, 8, 2 }, { 0, 0, 0 }, { 0, 0, 0 }, { 8, 15, 6 }},
02232 {{ 15, 7, 0 }, { 8, 0, 4 }, { 0, 0, 0 }, { 0,  0, 0 }},
02233 {{  0, 0, 0 }, { 0, 0, 0 }, { 0, 8, 4 }, { 7, 15, 0 }},
02234 };
02235 
02248 static Track DoTrainPathfind(const Train *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks, bool &path_found, bool do_track_reservation, PBSTileInfo *dest)
02249 {
02250   switch (_settings_game.pf.pathfinder_for_trains) {
02251     case VPF_NPF: return NPFTrainChooseTrack(v, tile, enterdir, tracks, path_found, do_track_reservation, dest);
02252     case VPF_YAPF: return YapfTrainChooseTrack(v, tile, enterdir, tracks, path_found, do_track_reservation, dest);
02253 
02254     default: NOT_REACHED();
02255   }
02256 }
02257 
02263 static PBSTileInfo ExtendTrainReservation(const Train *v, TrackBits *new_tracks, DiagDirection *enterdir)
02264 {
02265   PBSTileInfo origin = FollowTrainReservation(v);
02266 
02267   CFollowTrackRail ft(v);
02268 
02269   TileIndex tile = origin.tile;
02270   Trackdir  cur_td = origin.trackdir;
02271   while (ft.Follow(tile, cur_td)) {
02272     if (KillFirstBit(ft.m_new_td_bits) == TRACKDIR_BIT_NONE) {
02273       /* Possible signal tile. */
02274       if (HasOnewaySignalBlockingTrackdir(ft.m_new_tile, FindFirstTrackdir(ft.m_new_td_bits))) break;
02275     }
02276 
02277     if (_settings_game.pf.forbid_90_deg) {
02278       ft.m_new_td_bits &= ~TrackdirCrossesTrackdirs(ft.m_old_td);
02279       if (ft.m_new_td_bits == TRACKDIR_BIT_NONE) break;
02280     }
02281 
02282     /* Station, depot or waypoint are a possible target. */
02283     bool target_seen = ft.m_is_station || (IsTileType(ft.m_new_tile, MP_RAILWAY) && !IsPlainRail(ft.m_new_tile));
02284     if (target_seen || KillFirstBit(ft.m_new_td_bits) != TRACKDIR_BIT_NONE) {
02285       /* Choice found or possible target encountered.
02286        * On finding a possible target, we need to stop and let the pathfinder handle the
02287        * remaining path. This is because we don't know if this target is in one of our
02288        * orders, so we might cause pathfinding to fail later on if we find a choice.
02289        * This failure would cause a bogous call to TryReserveSafePath which might reserve
02290        * a wrong path not leading to our next destination. */
02291       if (HasReservedTracks(ft.m_new_tile, TrackdirBitsToTrackBits(TrackdirReachesTrackdirs(ft.m_old_td)))) break;
02292 
02293       /* If we did skip some tiles, backtrack to the first skipped tile so the pathfinder
02294        * actually starts its search at the first unreserved tile. */
02295       if (ft.m_tiles_skipped != 0) ft.m_new_tile -= TileOffsByDiagDir(ft.m_exitdir) * ft.m_tiles_skipped;
02296 
02297       /* Choice found, path valid but not okay. Save info about the choice tile as well. */
02298       if (new_tracks != NULL) *new_tracks = TrackdirBitsToTrackBits(ft.m_new_td_bits);
02299       if (enterdir != NULL) *enterdir = ft.m_exitdir;
02300       return PBSTileInfo(ft.m_new_tile, ft.m_old_td, false);
02301     }
02302 
02303     tile = ft.m_new_tile;
02304     cur_td = FindFirstTrackdir(ft.m_new_td_bits);
02305 
02306     if (IsSafeWaitingPosition(v, tile, cur_td, true, _settings_game.pf.forbid_90_deg)) {
02307       bool wp_free = IsWaitingPositionFree(v, tile, cur_td, _settings_game.pf.forbid_90_deg);
02308       if (!(wp_free && TryReserveRailTrack(tile, TrackdirToTrack(cur_td)))) break;
02309       /* Safe position is all good, path valid and okay. */
02310       return PBSTileInfo(tile, cur_td, true);
02311     }
02312 
02313     if (!TryReserveRailTrack(tile, TrackdirToTrack(cur_td))) break;
02314   }
02315 
02316   if (ft.m_err == CFollowTrackRail::EC_OWNER || ft.m_err == CFollowTrackRail::EC_NO_WAY) {
02317     /* End of line, path valid and okay. */
02318     return PBSTileInfo(ft.m_old_tile, ft.m_old_td, true);
02319   }
02320 
02321   /* Sorry, can't reserve path, back out. */
02322   tile = origin.tile;
02323   cur_td = origin.trackdir;
02324   TileIndex stopped = ft.m_old_tile;
02325   Trackdir  stopped_td = ft.m_old_td;
02326   while (tile != stopped || cur_td != stopped_td) {
02327     if (!ft.Follow(tile, cur_td)) break;
02328 
02329     if (_settings_game.pf.forbid_90_deg) {
02330       ft.m_new_td_bits &= ~TrackdirCrossesTrackdirs(ft.m_old_td);
02331       assert(ft.m_new_td_bits != TRACKDIR_BIT_NONE);
02332     }
02333     assert(KillFirstBit(ft.m_new_td_bits) == TRACKDIR_BIT_NONE);
02334 
02335     tile = ft.m_new_tile;
02336     cur_td = FindFirstTrackdir(ft.m_new_td_bits);
02337 
02338     UnreserveRailTrack(tile, TrackdirToTrack(cur_td));
02339   }
02340 
02341   /* Path invalid. */
02342   return PBSTileInfo();
02343 }
02344 
02355 static bool TryReserveSafeTrack(const Train *v, TileIndex tile, Trackdir td, bool override_tailtype)
02356 {
02357   switch (_settings_game.pf.pathfinder_for_trains) {
02358     case VPF_NPF: return NPFTrainFindNearestSafeTile(v, tile, td, override_tailtype);
02359     case VPF_YAPF: return YapfTrainFindNearestSafeTile(v, tile, td, override_tailtype);
02360 
02361     default: NOT_REACHED();
02362   }
02363 }
02364 
02366 class VehicleOrderSaver {
02367 private:
02368   Train          *v;
02369   Order          old_order;
02370   TileIndex      old_dest_tile;
02371   StationID      old_last_station_visited;
02372   VehicleOrderID index;
02373   bool           suppress_implicit_orders;
02374 
02375 public:
02376   VehicleOrderSaver(Train *_v) :
02377     v(_v),
02378     old_order(_v->current_order),
02379     old_dest_tile(_v->dest_tile),
02380     old_last_station_visited(_v->last_station_visited),
02381     index(_v->cur_real_order_index),
02382     suppress_implicit_orders(HasBit(_v->gv_flags, GVF_SUPPRESS_IMPLICIT_ORDERS))
02383   {
02384   }
02385 
02386   ~VehicleOrderSaver()
02387   {
02388     this->v->current_order = this->old_order;
02389     this->v->dest_tile = this->old_dest_tile;
02390     this->v->last_station_visited = this->old_last_station_visited;
02391     SB(this->v->gv_flags, GVF_SUPPRESS_IMPLICIT_ORDERS, 1, suppress_implicit_orders ? 1: 0);
02392   }
02393 
02399   bool SwitchToNextOrder(bool skip_first)
02400   {
02401     if (this->v->GetNumOrders() == 0) return false;
02402 
02403     if (skip_first) ++this->index;
02404 
02405     int depth = 0;
02406 
02407     do {
02408       /* Wrap around. */
02409       if (this->index >= this->v->GetNumOrders()) this->index = 0;
02410 
02411       Order *order = this->v->GetOrder(this->index);
02412       assert(order != NULL);
02413 
02414       switch (order->GetType()) {
02415         case OT_GOTO_DEPOT:
02416           /* Skip service in depot orders when the train doesn't need service. */
02417           if ((order->GetDepotOrderType() & ODTFB_SERVICE) && !this->v->NeedsServicing()) break;
02418         case OT_GOTO_STATION:
02419         case OT_GOTO_WAYPOINT:
02420           this->v->current_order = *order;
02421           return UpdateOrderDest(this->v, order, 0, true);
02422         case OT_CONDITIONAL: {
02423           VehicleOrderID next = ProcessConditionalOrder(order, this->v);
02424           if (next != INVALID_VEH_ORDER_ID) {
02425             depth++;
02426             this->index = next;
02427             /* Don't increment next, so no break here. */
02428             continue;
02429           }
02430           break;
02431         }
02432         default:
02433           break;
02434       }
02435       /* Don't increment inside the while because otherwise conditional
02436        * orders can lead to an infinite loop. */
02437       ++this->index;
02438       depth++;
02439     } while (this->index != this->v->cur_real_order_index && depth < this->v->GetNumOrders());
02440 
02441     return false;
02442   }
02443 };
02444 
02445 /* choose a track */
02446 static Track ChooseTrainTrack(Train *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks, bool force_res, bool *got_reservation, bool mark_stuck)
02447 {
02448   Track best_track = INVALID_TRACK;
02449   bool do_track_reservation = _settings_game.pf.reserve_paths || force_res;
02450   bool changed_signal = false;
02451 
02452   assert((tracks & ~TRACK_BIT_MASK) == 0);
02453 
02454   if (got_reservation != NULL) *got_reservation = false;
02455 
02456   /* Don't use tracks here as the setting to forbid 90 deg turns might have been switched between reservation and now. */
02457   TrackBits res_tracks = (TrackBits)(GetReservedTrackbits(tile) & DiagdirReachesTracks(enterdir));
02458   /* Do we have a suitable reserved track? */
02459   if (res_tracks != TRACK_BIT_NONE) return FindFirstTrack(res_tracks);
02460 
02461   /* Quick return in case only one possible track is available */
02462   if (KillFirstBit(tracks) == TRACK_BIT_NONE) {
02463     Track track = FindFirstTrack(tracks);
02464     /* We need to check for signals only here, as a junction tile can't have signals. */
02465     if (track != INVALID_TRACK && HasPbsSignalOnTrackdir(tile, TrackEnterdirToTrackdir(track, enterdir))) {
02466       do_track_reservation = true;
02467       changed_signal = true;
02468       SetSignalStateByTrackdir(tile, TrackEnterdirToTrackdir(track, enterdir), SIGNAL_STATE_GREEN);
02469     } else if (!do_track_reservation) {
02470       return track;
02471     }
02472     best_track = track;
02473   }
02474 
02475   PBSTileInfo   res_dest(tile, INVALID_TRACKDIR, false);
02476   DiagDirection dest_enterdir = enterdir;
02477   if (do_track_reservation) {
02478     res_dest = ExtendTrainReservation(v, &tracks, &dest_enterdir);
02479     if (res_dest.tile == INVALID_TILE) {
02480       /* Reservation failed? */
02481       if (mark_stuck) MarkTrainAsStuck(v);
02482       if (changed_signal) SetSignalStateByTrackdir(tile, TrackEnterdirToTrackdir(best_track, enterdir), SIGNAL_STATE_RED);
02483       return FindFirstTrack(tracks);
02484     }
02485     if (res_dest.okay) {
02486       /* Got a valid reservation that ends at a safe target, quick exit. */
02487       if (got_reservation != NULL) *got_reservation = true;
02488       if (changed_signal) MarkTileDirtyByTile(tile);
02489       TryReserveRailTrack(v->tile, TrackdirToTrack(v->GetVehicleTrackdir()));
02490       return best_track;
02491     }
02492 
02493     /* Check if the train needs service here, so it has a chance to always find a depot.
02494      * Also check if the current order is a service order so we don't reserve a path to
02495      * the destination but instead to the next one if service isn't needed. */
02496     CheckIfTrainNeedsService(v);
02497     if (v->current_order.IsType(OT_DUMMY) || v->current_order.IsType(OT_CONDITIONAL) || v->current_order.IsType(OT_GOTO_DEPOT)) ProcessOrders(v);
02498   }
02499 
02500   /* Save the current train order. The destructor will restore the old order on function exit. */
02501   VehicleOrderSaver orders(v);
02502 
02503   /* If the current tile is the destination of the current order and
02504    * a reservation was requested, advance to the next order.
02505    * Don't advance on a depot order as depots are always safe end points
02506    * for a path and no look-ahead is necessary. This also avoids a
02507    * problem with depot orders not part of the order list when the
02508    * order list itself is empty. */
02509   if (v->current_order.IsType(OT_LEAVESTATION)) {
02510     orders.SwitchToNextOrder(false);
02511   } else if (v->current_order.IsType(OT_LOADING) || (!v->current_order.IsType(OT_GOTO_DEPOT) && (
02512       v->current_order.IsType(OT_GOTO_STATION) ?
02513       IsRailStationTile(v->tile) && v->current_order.GetDestination() == GetStationIndex(v->tile) :
02514       v->tile == v->dest_tile))) {
02515     orders.SwitchToNextOrder(true);
02516   }
02517 
02518   if (res_dest.tile != INVALID_TILE && !res_dest.okay) {
02519     /* Pathfinders are able to tell that route was only 'guessed'. */
02520     bool      path_found = true;
02521     TileIndex new_tile = res_dest.tile;
02522 
02523     Track next_track = DoTrainPathfind(v, new_tile, dest_enterdir, tracks, path_found, do_track_reservation, &res_dest);
02524     if (new_tile == tile) best_track = next_track;
02525     v->HandlePathfindingResult(path_found);
02526   }
02527 
02528   /* No track reservation requested -> finished. */
02529   if (!do_track_reservation) return best_track;
02530 
02531   /* A path was found, but could not be reserved. */
02532   if (res_dest.tile != INVALID_TILE && !res_dest.okay) {
02533     if (mark_stuck) MarkTrainAsStuck(v);
02534     FreeTrainTrackReservation(v);
02535     return best_track;
02536   }
02537 
02538   /* No possible reservation target found, we are probably lost. */
02539   if (res_dest.tile == INVALID_TILE) {
02540     /* Try to find any safe destination. */
02541     PBSTileInfo origin = FollowTrainReservation(v);
02542     if (TryReserveSafeTrack(v, origin.tile, origin.trackdir, false)) {
02543       TrackBits res = GetReservedTrackbits(tile) & DiagdirReachesTracks(enterdir);
02544       best_track = FindFirstTrack(res);
02545       TryReserveRailTrack(v->tile, TrackdirToTrack(v->GetVehicleTrackdir()));
02546       if (got_reservation != NULL) *got_reservation = true;
02547       if (changed_signal) MarkTileDirtyByTile(tile);
02548     } else {
02549       FreeTrainTrackReservation(v);
02550       if (mark_stuck) MarkTrainAsStuck(v);
02551     }
02552     return best_track;
02553   }
02554 
02555   if (got_reservation != NULL) *got_reservation = true;
02556 
02557   /* Reservation target found and free, check if it is safe. */
02558   while (!IsSafeWaitingPosition(v, res_dest.tile, res_dest.trackdir, true, _settings_game.pf.forbid_90_deg)) {
02559     /* Extend reservation until we have found a safe position. */
02560     DiagDirection exitdir = TrackdirToExitdir(res_dest.trackdir);
02561     TileIndex     next_tile = TileAddByDiagDir(res_dest.tile, exitdir);
02562     TrackBits     reachable = TrackdirBitsToTrackBits((TrackdirBits)(GetTileTrackStatus(next_tile, TRANSPORT_RAIL, 0))) & DiagdirReachesTracks(exitdir);
02563     if (_settings_game.pf.forbid_90_deg) {
02564       reachable &= ~TrackCrossesTracks(TrackdirToTrack(res_dest.trackdir));
02565     }
02566 
02567     /* Get next order with destination. */
02568     if (orders.SwitchToNextOrder(true)) {
02569       PBSTileInfo cur_dest;
02570       bool path_found;
02571       DoTrainPathfind(v, next_tile, exitdir, reachable, path_found, true, &cur_dest);
02572       if (cur_dest.tile != INVALID_TILE) {
02573         res_dest = cur_dest;
02574         if (res_dest.okay) continue;
02575         /* Path found, but could not be reserved. */
02576         FreeTrainTrackReservation(v);
02577         if (mark_stuck) MarkTrainAsStuck(v);
02578         if (got_reservation != NULL) *got_reservation = false;
02579         changed_signal = false;
02580         break;
02581       }
02582     }
02583     /* No order or no safe position found, try any position. */
02584     if (!TryReserveSafeTrack(v, res_dest.tile, res_dest.trackdir, true)) {
02585       FreeTrainTrackReservation(v);
02586       if (mark_stuck) MarkTrainAsStuck(v);
02587       if (got_reservation != NULL) *got_reservation = false;
02588       changed_signal = false;
02589     }
02590     break;
02591   }
02592 
02593   TryReserveRailTrack(v->tile, TrackdirToTrack(v->GetVehicleTrackdir()));
02594 
02595   if (changed_signal) MarkTileDirtyByTile(tile);
02596 
02597   return best_track;
02598 }
02599 
02608 bool TryPathReserve(Train *v, bool mark_as_stuck, bool first_tile_okay)
02609 {
02610   assert(v->IsFrontEngine());
02611 
02612   /* We have to handle depots specially as the track follower won't look
02613    * at the depot tile itself but starts from the next tile. If we are still
02614    * inside the depot, a depot reservation can never be ours. */
02615   if (v->track == TRACK_BIT_DEPOT) {
02616     if (HasDepotReservation(v->tile)) {
02617       if (mark_as_stuck) MarkTrainAsStuck(v);
02618       return false;
02619     } else {
02620       /* Depot not reserved, but the next tile might be. */
02621       TileIndex next_tile = TileAddByDiagDir(v->tile, GetRailDepotDirection(v->tile));
02622       if (HasReservedTracks(next_tile, DiagdirReachesTracks(GetRailDepotDirection(v->tile)))) return false;
02623     }
02624   }
02625 
02626   Vehicle *other_train = NULL;
02627   PBSTileInfo origin = FollowTrainReservation(v, &other_train);
02628   /* The path we are driving on is already blocked by some other train.
02629    * This can only happen in certain situations when mixing path and
02630    * block signals or when changing tracks and/or signals.
02631    * Exit here as doing any further reservations will probably just
02632    * make matters worse. */
02633   if (other_train != NULL && other_train->index != v->index) {
02634     if (mark_as_stuck) MarkTrainAsStuck(v);
02635     return false;
02636   }
02637   /* If we have a reserved path and the path ends at a safe tile, we are finished already. */
02638   if (origin.okay && (v->tile != origin.tile || first_tile_okay)) {
02639     /* Can't be stuck then. */
02640     if (HasBit(v->flags, VRF_TRAIN_STUCK)) SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
02641     ClrBit(v->flags, VRF_TRAIN_STUCK);
02642     return true;
02643   }
02644 
02645   /* If we are in a depot, tentatively reserve the depot. */
02646   if (v->track == TRACK_BIT_DEPOT) {
02647     SetDepotReservation(v->tile, true);
02648     if (_settings_client.gui.show_track_reservation) MarkTileDirtyByTile(v->tile);
02649   }
02650 
02651   DiagDirection exitdir = TrackdirToExitdir(origin.trackdir);
02652   TileIndex     new_tile = TileAddByDiagDir(origin.tile, exitdir);
02653   TrackBits     reachable = TrackdirBitsToTrackBits(TrackStatusToTrackdirBits(GetTileTrackStatus(new_tile, TRANSPORT_RAIL, 0)) & DiagdirReachesTrackdirs(exitdir));
02654 
02655   if (_settings_game.pf.forbid_90_deg) reachable &= ~TrackCrossesTracks(TrackdirToTrack(origin.trackdir));
02656 
02657   bool res_made = false;
02658   ChooseTrainTrack(v, new_tile, exitdir, reachable, true, &res_made, mark_as_stuck);
02659 
02660   if (!res_made) {
02661     /* Free the depot reservation as well. */
02662     if (v->track == TRACK_BIT_DEPOT) SetDepotReservation(v->tile, false);
02663     return false;
02664   }
02665 
02666   if (HasBit(v->flags, VRF_TRAIN_STUCK)) {
02667     v->wait_counter = 0;
02668     SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
02669   }
02670   ClrBit(v->flags, VRF_TRAIN_STUCK);
02671   return true;
02672 }
02673 
02674 
02675 static bool CheckReverseTrain(const Train *v)
02676 {
02677   if (_settings_game.difficulty.line_reverse_mode != 0 ||
02678       v->track == TRACK_BIT_DEPOT || v->track == TRACK_BIT_WORMHOLE ||
02679       !(v->direction & 1)) {
02680     return false;
02681   }
02682 
02683   assert(v->track != TRACK_BIT_NONE);
02684 
02685   switch (_settings_game.pf.pathfinder_for_trains) {
02686     case VPF_NPF: return NPFTrainCheckReverse(v);
02687     case VPF_YAPF: return YapfTrainCheckReverse(v);
02688 
02689     default: NOT_REACHED();
02690   }
02691 }
02692 
02698 TileIndex Train::GetOrderStationLocation(StationID station)
02699 {
02700   if (station == this->last_station_visited) this->last_station_visited = INVALID_STATION;
02701 
02702   const Station *st = Station::Get(station);
02703   if (!(st->facilities & FACIL_TRAIN)) {
02704     /* The destination station has no trainstation tiles. */
02705     this->IncrementRealOrderIndex();
02706     return 0;
02707   }
02708 
02709   return st->xy;
02710 }
02711 
02713 void Train::MarkDirty()
02714 {
02715   Train *v = this;
02716   do {
02717     v->UpdateViewport(false, false);
02718   } while ((v = v->Next()) != NULL);
02719 
02720   /* need to update acceleration and cached values since the goods on the train changed. */
02721   this->CargoChanged();
02722   this->UpdateAcceleration();
02723 }
02724 
02732 int Train::UpdateSpeed()
02733 {
02734   switch (_settings_game.vehicle.train_acceleration_model) {
02735     default: NOT_REACHED();
02736     case AM_ORIGINAL:
02737       return this->DoUpdateSpeed(this->acceleration * (this->GetAccelerationStatus() == AS_BRAKE ? -4 : 2), 0, min(this->gcache.cached_max_track_speed, this->current_order.max_speed));
02738 
02739     case AM_REALISTIC:
02740       return this->DoUpdateSpeed(this->GetAcceleration(), this->GetAccelerationStatus() == AS_BRAKE ? 0 : 2, this->GetCurrentMaxSpeed());
02741   }
02742 }
02743 
02749 static void TrainEnterStation(Train *v, StationID station)
02750 {
02751   v->last_station_visited = station;
02752 
02753   /* check if a train ever visited this station before */
02754   Station *st = Station::Get(station);
02755   if (!(st->had_vehicle_of_type & HVOT_TRAIN)) {
02756     st->had_vehicle_of_type |= HVOT_TRAIN;
02757     SetDParam(0, st->index);
02758     AddVehicleNewsItem(
02759       STR_NEWS_FIRST_TRAIN_ARRIVAL,
02760       v->owner == _local_company ? NS_ARRIVAL_COMPANY : NS_ARRIVAL_OTHER,
02761       v->index,
02762       st->index
02763     );
02764     AI::NewEvent(v->owner, new ScriptEventStationFirstVehicle(st->index, v->index));
02765     Game::NewEvent(new ScriptEventStationFirstVehicle(st->index, v->index));
02766   }
02767 
02768   v->force_proceed = TFP_NONE;
02769   SetWindowDirty(WC_VEHICLE_VIEW, v->index);
02770 
02771   v->BeginLoading();
02772 
02773   TriggerStationAnimation(st, v->tile, SAT_TRAIN_ARRIVES);
02774 }
02775 
02776 /* Check if the vehicle is compatible with the specified tile */
02777 static inline bool CheckCompatibleRail(const Train *v, TileIndex tile)
02778 {
02779   return IsTileOwner(tile, v->owner) &&
02780       (!v->IsFrontEngine() || HasBit(v->compatible_railtypes, GetRailType(tile)));
02781 }
02782 
02784 struct AccelerationSlowdownParams {
02785   byte small_turn; 
02786   byte large_turn; 
02787   byte z_up;       
02788   byte z_down;     
02789 };
02790 
02792 static const AccelerationSlowdownParams _accel_slowdown[] = {
02793   /* normal accel */
02794   {256 / 4, 256 / 2, 256 / 4, 2}, 
02795   {256 / 4, 256 / 2, 256 / 4, 2}, 
02796   {0,       256 / 2, 256 / 4, 2}, 
02797 };
02798 
02804 static inline void AffectSpeedByZChange(Train *v, int old_z)
02805 {
02806   if (old_z == v->z_pos || _settings_game.vehicle.train_acceleration_model != AM_ORIGINAL) return;
02807 
02808   const AccelerationSlowdownParams *asp = &_accel_slowdown[GetRailTypeInfo(v->railtype)->acceleration_type];
02809 
02810   if (old_z < v->z_pos) {
02811     v->cur_speed -= (v->cur_speed * asp->z_up >> 8);
02812   } else {
02813     uint16 spd = v->cur_speed + asp->z_down;
02814     if (spd <= v->gcache.cached_max_track_speed) v->cur_speed = spd;
02815   }
02816 }
02817 
02818 static bool TrainMovedChangeSignals(TileIndex tile, DiagDirection dir)
02819 {
02820   if (IsTileType(tile, MP_RAILWAY) &&
02821       GetRailTileType(tile) == RAIL_TILE_SIGNALS) {
02822     TrackdirBits tracks = TrackBitsToTrackdirBits(GetTrackBits(tile)) & DiagdirReachesTrackdirs(dir);
02823     Trackdir trackdir = FindFirstTrackdir(tracks);
02824     if (UpdateSignalsOnSegment(tile,  TrackdirToExitdir(trackdir), GetTileOwner(tile)) == SIGSEG_PBS && HasSignalOnTrackdir(tile, trackdir)) {
02825       /* A PBS block with a non-PBS signal facing us? */
02826       if (!IsPbsSignal(GetSignalType(tile, TrackdirToTrack(trackdir)))) return true;
02827     }
02828   }
02829   return false;
02830 }
02831 
02833 void Train::ReserveTrackUnderConsist() const
02834 {
02835   for (const Train *u = this; u != NULL; u = u->Next()) {
02836     switch (u->track) {
02837       case TRACK_BIT_WORMHOLE:
02838         TryReserveRailTrack(u->tile, DiagDirToDiagTrack(GetTunnelBridgeDirection(u->tile)));
02839         break;
02840       case TRACK_BIT_DEPOT:
02841         break;
02842       default:
02843         TryReserveRailTrack(u->tile, TrackBitsToTrack(u->track));
02844         break;
02845     }
02846   }
02847 }
02848 
02855 uint Train::Crash(bool flooded)
02856 {
02857   uint pass = 0;
02858   if (this->IsFrontEngine()) {
02859     pass += 2; // driver
02860 
02861     /* Remove the reserved path in front of the train if it is not stuck.
02862      * Also clear all reserved tracks the train is currently on. */
02863     if (!HasBit(this->flags, VRF_TRAIN_STUCK)) FreeTrainTrackReservation(this);
02864     for (const Train *v = this; v != NULL; v = v->Next()) {
02865       ClearPathReservation(v, v->tile, v->GetVehicleTrackdir());
02866       if (IsTileType(v->tile, MP_TUNNELBRIDGE)) {
02867         /* ClearPathReservation will not free the wormhole exit
02868          * if the train has just entered the wormhole. */
02869         SetTunnelBridgeReservation(GetOtherTunnelBridgeEnd(v->tile), false);
02870       }
02871     }
02872 
02873     /* we may need to update crossing we were approaching,
02874      * but must be updated after the train has been marked crashed */
02875     TileIndex crossing = TrainApproachingCrossingTile(this);
02876     if (crossing != INVALID_TILE) UpdateLevelCrossing(crossing);
02877 
02878     /* Remove the loading indicators (if any) */
02879     HideFillingPercent(&this->fill_percent_te_id);
02880   }
02881 
02882   pass += this->GroundVehicleBase::Crash(flooded);
02883 
02884   this->crash_anim_pos = flooded ? 4000 : 1; // max 4440, disappear pretty fast when flooded
02885   return pass;
02886 }
02887 
02894 static uint TrainCrashed(Train *v)
02895 {
02896   uint num = 0;
02897 
02898   /* do not crash train twice */
02899   if (!(v->vehstatus & VS_CRASHED)) {
02900     num = v->Crash();
02901     AI::NewEvent(v->owner, new ScriptEventVehicleCrashed(v->index, v->tile, ScriptEventVehicleCrashed::CRASH_TRAIN));
02902     Game::NewEvent(new ScriptEventVehicleCrashed(v->index, v->tile, ScriptEventVehicleCrashed::CRASH_TRAIN));
02903   }
02904 
02905   /* Try to re-reserve track under already crashed train too.
02906    * Crash() clears the reservation! */
02907   v->ReserveTrackUnderConsist();
02908 
02909   return num;
02910 }
02911 
02913 struct TrainCollideChecker {
02914   Train *v; 
02915   uint num; 
02916 };
02917 
02924 static Vehicle *FindTrainCollideEnum(Vehicle *v, void *data)
02925 {
02926   TrainCollideChecker *tcc = (TrainCollideChecker*)data;
02927 
02928   /* not a train or in depot */
02929   if (v->type != VEH_TRAIN || Train::From(v)->track == TRACK_BIT_DEPOT) return NULL;
02930 
02931   /* do not crash into trains of another company. */
02932   if (v->owner != tcc->v->owner) return NULL;
02933 
02934   /* get first vehicle now to make most usual checks faster */
02935   Train *coll = Train::From(v)->First();
02936 
02937   /* can't collide with own wagons */
02938   if (coll == tcc->v) return NULL;
02939 
02940   int x_diff = v->x_pos - tcc->v->x_pos;
02941   int y_diff = v->y_pos - tcc->v->y_pos;
02942 
02943   /* Do fast calculation to check whether trains are not in close vicinity
02944    * and quickly reject trains distant enough for any collision.
02945    * Differences are shifted by 7, mapping range [-7 .. 8] into [0 .. 15]
02946    * Differences are then ORed and then we check for any higher bits */
02947   uint hash = (y_diff + 7) | (x_diff + 7);
02948   if (hash & ~15) return NULL;
02949 
02950   /* Slower check using multiplication */
02951   int min_diff = (Train::From(v)->gcache.cached_veh_length + 1) / 2 + (tcc->v->gcache.cached_veh_length + 1) / 2 - 1;
02952   if (x_diff * x_diff + y_diff * y_diff > min_diff * min_diff) return NULL;
02953 
02954   /* Happens when there is a train under bridge next to bridge head */
02955   if (abs(v->z_pos - tcc->v->z_pos) > 5) return NULL;
02956 
02957   /* crash both trains */
02958   tcc->num += TrainCrashed(tcc->v);
02959   tcc->num += TrainCrashed(coll);
02960 
02961   return NULL; // continue searching
02962 }
02963 
02971 static bool CheckTrainCollision(Train *v)
02972 {
02973   /* can't collide in depot */
02974   if (v->track == TRACK_BIT_DEPOT) return false;
02975 
02976   assert(v->track == TRACK_BIT_WORMHOLE || TileVirtXY(v->x_pos, v->y_pos) == v->tile);
02977 
02978   TrainCollideChecker tcc;
02979   tcc.v = v;
02980   tcc.num = 0;
02981 
02982   /* find colliding vehicles */
02983   if (v->track == TRACK_BIT_WORMHOLE) {
02984     FindVehicleOnPos(v->tile, &tcc, FindTrainCollideEnum);
02985     FindVehicleOnPos(GetOtherTunnelBridgeEnd(v->tile), &tcc, FindTrainCollideEnum);
02986   } else {
02987     FindVehicleOnPosXY(v->x_pos, v->y_pos, &tcc, FindTrainCollideEnum);
02988   }
02989 
02990   /* any dead -> no crash */
02991   if (tcc.num == 0) return false;
02992 
02993   SetDParam(0, tcc.num);
02994   AddVehicleNewsItem(STR_NEWS_TRAIN_CRASH,
02995     NS_ACCIDENT,
02996     v->index
02997   );
02998 
02999   ModifyStationRatingAround(v->tile, v->owner, -160, 30);
03000   SndPlayVehicleFx(SND_13_BIG_CRASH, v);
03001   return true;
03002 }
03003 
03004 static Vehicle *CheckTrainAtSignal(Vehicle *v, void *data)
03005 {
03006   if (v->type != VEH_TRAIN || (v->vehstatus & VS_CRASHED)) return NULL;
03007 
03008   Train *t = Train::From(v);
03009   DiagDirection exitdir = *(DiagDirection *)data;
03010 
03011   /* not front engine of a train, inside wormhole or depot, crashed */
03012   if (!t->IsFrontEngine() || !(t->track & TRACK_BIT_MASK)) return NULL;
03013 
03014   if (t->cur_speed > 5 || TrainExitDir(t->direction, t->track) != exitdir) return NULL;
03015 
03016   return t;
03017 }
03018 
03026 bool TrainController(Train *v, Vehicle *nomove, bool reverse)
03027 {
03028   Train *first = v->First();
03029   Train *prev;
03030   bool direction_changed = false; // has direction of any part changed?
03031 
03032   /* For every vehicle after and including the given vehicle */
03033   for (prev = v->Previous(); v != nomove; prev = v, v = v->Next()) {
03034     DiagDirection enterdir = DIAGDIR_BEGIN;
03035     bool update_signals_crossing = false; // will we update signals or crossing state?
03036 
03037     GetNewVehiclePosResult gp = GetNewVehiclePos(v);
03038     if (v->track != TRACK_BIT_WORMHOLE) {
03039       /* Not inside tunnel */
03040       if (gp.old_tile == gp.new_tile) {
03041         /* Staying in the old tile */
03042         if (v->track == TRACK_BIT_DEPOT) {
03043           /* Inside depot */
03044           gp.x = v->x_pos;
03045           gp.y = v->y_pos;
03046         } else {
03047           /* Not inside depot */
03048 
03049           /* Reverse when we are at the end of the track already, do not move to the new position */
03050           if (v->IsFrontEngine() && !TrainCheckIfLineEnds(v, reverse)) return false;
03051 
03052           uint32 r = VehicleEnterTile(v, gp.new_tile, gp.x, gp.y);
03053           if (HasBit(r, VETS_CANNOT_ENTER)) {
03054             goto invalid_rail;
03055           }
03056           if (HasBit(r, VETS_ENTERED_STATION)) {
03057             /* The new position is the end of the platform */
03058             TrainEnterStation(v, r >> VETS_STATION_ID_OFFSET);
03059           }
03060         }
03061       } else {
03062         /* A new tile is about to be entered. */
03063 
03064         /* Determine what direction we're entering the new tile from */
03065         enterdir = DiagdirBetweenTiles(gp.old_tile, gp.new_tile);
03066         assert(IsValidDiagDirection(enterdir));
03067 
03068         /* Get the status of the tracks in the new tile and mask
03069          * away the bits that aren't reachable. */
03070         TrackStatus ts = GetTileTrackStatus(gp.new_tile, TRANSPORT_RAIL, 0, ReverseDiagDir(enterdir));
03071         TrackdirBits reachable_trackdirs = DiagdirReachesTrackdirs(enterdir);
03072 
03073         TrackdirBits trackdirbits = TrackStatusToTrackdirBits(ts) & reachable_trackdirs;
03074         TrackBits red_signals = TrackdirBitsToTrackBits(TrackStatusToRedSignals(ts) & reachable_trackdirs);
03075 
03076         TrackBits bits = TrackdirBitsToTrackBits(trackdirbits);
03077         if (_settings_game.pf.forbid_90_deg && prev == NULL) {
03078           /* We allow wagons to make 90 deg turns, because forbid_90_deg
03079            * can be switched on halfway a turn */
03080           bits &= ~TrackCrossesTracks(FindFirstTrack(v->track));
03081         }
03082 
03083         if (bits == TRACK_BIT_NONE) goto invalid_rail;
03084 
03085         /* Check if the new tile constrains tracks that are compatible
03086          * with the current train, if not, bail out. */
03087         if (!CheckCompatibleRail(v, gp.new_tile)) goto invalid_rail;
03088 
03089         TrackBits chosen_track;
03090         if (prev == NULL) {
03091           /* Currently the locomotive is active. Determine which one of the
03092            * available tracks to choose */
03093           chosen_track = TrackToTrackBits(ChooseTrainTrack(v, gp.new_tile, enterdir, bits, false, NULL, true));
03094           assert(chosen_track & (bits | GetReservedTrackbits(gp.new_tile)));
03095 
03096           if (v->force_proceed != TFP_NONE && IsPlainRailTile(gp.new_tile) && HasSignals(gp.new_tile)) {
03097             /* For each signal we find decrease the counter by one.
03098              * We start at two, so the first signal we pass decreases
03099              * this to one, then if we reach the next signal it is
03100              * decreased to zero and we won't pass that new signal. */
03101             Trackdir dir = FindFirstTrackdir(trackdirbits);
03102             if (GetSignalType(gp.new_tile, TrackdirToTrack(dir)) != SIGTYPE_PBS ||
03103                 !HasSignalOnTrackdir(gp.new_tile, ReverseTrackdir(dir))) {
03104               /* However, we do not want to be stopped by PBS signals
03105                * entered via the back. */
03106               v->force_proceed = (v->force_proceed == TFP_SIGNAL) ? TFP_STUCK : TFP_NONE;
03107               SetWindowDirty(WC_VEHICLE_VIEW, v->index);
03108             }
03109           }
03110 
03111           /* Check if it's a red signal and that force proceed is not clicked. */
03112           if ((red_signals & chosen_track) && v->force_proceed == TFP_NONE) {
03113             /* In front of a red signal */
03114             Trackdir i = FindFirstTrackdir(trackdirbits);
03115 
03116             /* Don't handle stuck trains here. */
03117             if (HasBit(v->flags, VRF_TRAIN_STUCK)) return false;
03118 
03119             if (!HasSignalOnTrackdir(gp.new_tile, ReverseTrackdir(i))) {
03120               v->cur_speed = 0;
03121               v->subspeed = 0;
03122               v->progress = 255 - 100;
03123               if (!_settings_game.pf.reverse_at_signals || ++v->wait_counter < _settings_game.pf.wait_oneway_signal * 20) return false;
03124             } else if (HasSignalOnTrackdir(gp.new_tile, i)) {
03125               v->cur_speed = 0;
03126               v->subspeed = 0;
03127               v->progress = 255 - 10;
03128               if (!_settings_game.pf.reverse_at_signals || ++v->wait_counter < _settings_game.pf.wait_twoway_signal * 73) {
03129                 DiagDirection exitdir = TrackdirToExitdir(i);
03130                 TileIndex o_tile = TileAddByDiagDir(gp.new_tile, exitdir);
03131 
03132                 exitdir = ReverseDiagDir(exitdir);
03133 
03134                 /* check if a train is waiting on the other side */
03135                 if (!HasVehicleOnPos(o_tile, &exitdir, &CheckTrainAtSignal)) return false;
03136               }
03137             }
03138 
03139             /* If we would reverse but are currently in a PBS block and
03140              * reversing of stuck trains is disabled, don't reverse.
03141              * This does not apply if the reason for reversing is a one-way
03142              * signal blocking us, because a train would then be stuck forever. */
03143             if (!_settings_game.pf.reverse_at_signals && !HasOnewaySignalBlockingTrackdir(gp.new_tile, i) &&
03144                 UpdateSignalsOnSegment(v->tile, enterdir, v->owner) == SIGSEG_PBS) {
03145               v->wait_counter = 0;
03146               return false;
03147             }
03148             goto reverse_train_direction;
03149           } else {
03150             TryReserveRailTrack(gp.new_tile, TrackBitsToTrack(chosen_track));
03151           }
03152         } else {
03153           /* The wagon is active, simply follow the prev vehicle. */
03154           if (prev->tile == gp.new_tile) {
03155             /* Choose the same track as prev */
03156             if (prev->track == TRACK_BIT_WORMHOLE) {
03157               /* Vehicles entering tunnels enter the wormhole earlier than for bridges.
03158                * However, just choose the track into the wormhole. */
03159               assert(IsTunnel(prev->tile));
03160               chosen_track = bits;
03161             } else {
03162               chosen_track = prev->track;
03163             }
03164           } else {
03165             /* Choose the track that leads to the tile where prev is.
03166              * This case is active if 'prev' is already on the second next tile, when 'v' just enters the next tile.
03167              * I.e. when the tile between them has only space for a single vehicle like
03168              *  1) horizontal/vertical track tiles and
03169              *  2) some orientations of tunnel entries, where the vehicle is already inside the wormhole at 8/16 from the tile edge.
03170              *     Is also the train just reversing, the wagon inside the tunnel is 'on' the tile of the opposite tunnel entry.
03171              */
03172             static const TrackBits _connecting_track[DIAGDIR_END][DIAGDIR_END] = {
03173               {TRACK_BIT_X,     TRACK_BIT_LOWER, TRACK_BIT_NONE,  TRACK_BIT_LEFT },
03174               {TRACK_BIT_UPPER, TRACK_BIT_Y,     TRACK_BIT_LEFT,  TRACK_BIT_NONE },
03175               {TRACK_BIT_NONE,  TRACK_BIT_RIGHT, TRACK_BIT_X,     TRACK_BIT_UPPER},
03176               {TRACK_BIT_RIGHT, TRACK_BIT_NONE,  TRACK_BIT_LOWER, TRACK_BIT_Y    }
03177             };
03178             DiagDirection exitdir = DiagdirBetweenTiles(gp.new_tile, prev->tile);
03179             assert(IsValidDiagDirection(exitdir));
03180             chosen_track = _connecting_track[enterdir][exitdir];
03181           }
03182           chosen_track &= bits;
03183         }
03184 
03185         /* Make sure chosen track is a valid track */
03186         assert(
03187             chosen_track == TRACK_BIT_X     || chosen_track == TRACK_BIT_Y ||
03188             chosen_track == TRACK_BIT_UPPER || chosen_track == TRACK_BIT_LOWER ||
03189             chosen_track == TRACK_BIT_LEFT  || chosen_track == TRACK_BIT_RIGHT);
03190 
03191         /* Update XY to reflect the entrance to the new tile, and select the direction to use */
03192         const byte *b = _initial_tile_subcoord[FIND_FIRST_BIT(chosen_track)][enterdir];
03193         gp.x = (gp.x & ~0xF) | b[0];
03194         gp.y = (gp.y & ~0xF) | b[1];
03195         Direction chosen_dir = (Direction)b[2];
03196 
03197         /* Call the landscape function and tell it that the vehicle entered the tile */
03198         uint32 r = VehicleEnterTile(v, gp.new_tile, gp.x, gp.y);
03199         if (HasBit(r, VETS_CANNOT_ENTER)) {
03200           goto invalid_rail;
03201         }
03202 
03203         if (!HasBit(r, VETS_ENTERED_WORMHOLE)) {
03204           Track track = FindFirstTrack(chosen_track);
03205           Trackdir tdir = TrackDirectionToTrackdir(track, chosen_dir);
03206           if (v->IsFrontEngine() && HasPbsSignalOnTrackdir(gp.new_tile, tdir)) {
03207             SetSignalStateByTrackdir(gp.new_tile, tdir, SIGNAL_STATE_RED);
03208             MarkTileDirtyByTile(gp.new_tile);
03209           }
03210 
03211           /* Clear any track reservation when the last vehicle leaves the tile */
03212           if (v->Next() == NULL) ClearPathReservation(v, v->tile, v->GetVehicleTrackdir());
03213 
03214           v->tile = gp.new_tile;
03215 
03216           if (GetTileRailType(gp.new_tile) != GetTileRailType(gp.old_tile)) {
03217             v->First()->ConsistChanged(true);
03218           }
03219 
03220           v->track = chosen_track;
03221           assert(v->track);
03222         }
03223 
03224         /* We need to update signal status, but after the vehicle position hash
03225          * has been updated by UpdateInclination() */
03226         update_signals_crossing = true;
03227 
03228         if (chosen_dir != v->direction) {
03229           if (prev == NULL && _settings_game.vehicle.train_acceleration_model == AM_ORIGINAL) {
03230             const AccelerationSlowdownParams *asp = &_accel_slowdown[GetRailTypeInfo(v->railtype)->acceleration_type];
03231             DirDiff diff = DirDifference(v->direction, chosen_dir);
03232             v->cur_speed -= (diff == DIRDIFF_45RIGHT || diff == DIRDIFF_45LEFT ? asp->small_turn : asp->large_turn) * v->cur_speed >> 8;
03233           }
03234           direction_changed = true;
03235           v->direction = chosen_dir;
03236         }
03237 
03238         if (v->IsFrontEngine()) {
03239           v->wait_counter = 0;
03240 
03241           /* If we are approaching a crossing that is reserved, play the sound now. */
03242           TileIndex crossing = TrainApproachingCrossingTile(v);
03243           if (crossing != INVALID_TILE && HasCrossingReservation(crossing)) SndPlayTileFx(SND_0E_LEVEL_CROSSING, crossing);
03244 
03245           /* Always try to extend the reservation when entering a tile. */
03246           CheckNextTrainTile(v);
03247         }
03248 
03249         if (HasBit(r, VETS_ENTERED_STATION)) {
03250           /* The new position is the location where we want to stop */
03251           TrainEnterStation(v, r >> VETS_STATION_ID_OFFSET);
03252         }
03253       }
03254     } else {
03255       /* In a tunnel or on a bridge
03256        * - for tunnels, only the part when the vehicle is not visible (part of enter/exit tile too)
03257        * - for bridges, only the middle part - without the bridge heads */
03258       if (!(v->vehstatus & VS_HIDDEN)) {
03259         Train *first = v->First();
03260         first->cur_speed = min(first->cur_speed, GetBridgeSpec(GetBridgeType(v->tile))->speed);
03261       }
03262 
03263       if (IsTileType(gp.new_tile, MP_TUNNELBRIDGE) && HasBit(VehicleEnterTile(v, gp.new_tile, gp.x, gp.y), VETS_ENTERED_WORMHOLE)) {
03264         /* Perform look-ahead on tunnel exit. */
03265         if (v->IsFrontEngine()) {
03266           TryReserveRailTrack(gp.new_tile, DiagDirToDiagTrack(GetTunnelBridgeDirection(gp.new_tile)));
03267           CheckNextTrainTile(v);
03268         }
03269         /* Prevent v->UpdateInclination() being called with wrong parameters.
03270          * This could happen if the train was reversed inside the tunnel/bridge. */
03271         if (gp.old_tile == gp.new_tile) {
03272           gp.old_tile = GetOtherTunnelBridgeEnd(gp.old_tile);
03273         }
03274       } else {
03275         v->x_pos = gp.x;
03276         v->y_pos = gp.y;
03277         VehicleUpdatePosition(v);
03278         if ((v->vehstatus & VS_HIDDEN) == 0) VehicleUpdateViewport(v, true);
03279         continue;
03280       }
03281     }
03282 
03283     /* update image of train, as well as delta XY */
03284     v->UpdateDeltaXY(v->direction);
03285 
03286     v->x_pos = gp.x;
03287     v->y_pos = gp.y;
03288     VehicleUpdatePosition(v);
03289 
03290     /* update the Z position of the vehicle */
03291     int old_z = v->UpdateInclination(gp.new_tile != gp.old_tile, false);
03292 
03293     if (prev == NULL) {
03294       /* This is the first vehicle in the train */
03295       AffectSpeedByZChange(v, old_z);
03296     }
03297 
03298     if (update_signals_crossing) {
03299       if (v->IsFrontEngine()) {
03300         if (TrainMovedChangeSignals(gp.new_tile, enterdir)) {
03301           /* We are entering a block with PBS signals right now, but
03302            * not through a PBS signal. This means we don't have a
03303            * reservation right now. As a conventional signal will only
03304            * ever be green if no other train is in the block, getting
03305            * a path should always be possible. If the player built
03306            * such a strange network that it is not possible, the train
03307            * will be marked as stuck and the player has to deal with
03308            * the problem. */
03309           if ((!HasReservedTracks(gp.new_tile, v->track) &&
03310               !TryReserveRailTrack(gp.new_tile, FindFirstTrack(v->track))) ||
03311               !TryPathReserve(v)) {
03312             MarkTrainAsStuck(v);
03313           }
03314         }
03315       }
03316 
03317       /* Signals can only change when the first
03318        * (above) or the last vehicle moves. */
03319       if (v->Next() == NULL) {
03320         TrainMovedChangeSignals(gp.old_tile, ReverseDiagDir(enterdir));
03321         if (IsLevelCrossingTile(gp.old_tile)) UpdateLevelCrossing(gp.old_tile);
03322       }
03323     }
03324 
03325     /* Do not check on every tick to save some computing time. */
03326     if (v->IsFrontEngine() && v->tick_counter % _settings_game.pf.path_backoff_interval == 0) CheckNextTrainTile(v);
03327   }
03328 
03329   if (direction_changed) first->tcache.cached_max_curve_speed = first->GetCurveSpeedLimit();
03330 
03331   return true;
03332 
03333 invalid_rail:
03334   /* We've reached end of line?? */
03335   if (prev != NULL) error("Disconnecting train");
03336 
03337 reverse_train_direction:
03338   if (reverse) {
03339     v->wait_counter = 0;
03340     v->cur_speed = 0;
03341     v->subspeed = 0;
03342     ReverseTrainDirection(v);
03343   }
03344 
03345   return false;
03346 }
03347 
03354 static Vehicle *CollectTrackbitsFromCrashedVehiclesEnum(Vehicle *v, void *data)
03355 {
03356   TrackBits *trackbits = (TrackBits *)data;
03357 
03358   if (v->type == VEH_TRAIN && (v->vehstatus & VS_CRASHED) != 0) {
03359     TrackBits train_tbits = Train::From(v)->track;
03360     if (train_tbits == TRACK_BIT_WORMHOLE) {
03361       /* Vehicle is inside a wormhole, v->track contains no useful value then. */
03362       *trackbits |= DiagDirToDiagTrackBits(GetTunnelBridgeDirection(v->tile));
03363     } else if (train_tbits != TRACK_BIT_DEPOT) {
03364       *trackbits |= train_tbits;
03365     }
03366   }
03367 
03368   return NULL;
03369 }
03370 
03378 static void DeleteLastWagon(Train *v)
03379 {
03380   Train *first = v->First();
03381 
03382   /* Go to the last wagon and delete the link pointing there
03383    * *u is then the one-before-last wagon, and *v the last
03384    * one which will physically be removed */
03385   Train *u = v;
03386   for (; v->Next() != NULL; v = v->Next()) u = v;
03387   u->SetNext(NULL);
03388 
03389   if (first != v) {
03390     /* Recalculate cached train properties */
03391     first->ConsistChanged(false);
03392     /* Update the depot window if the first vehicle is in depot -
03393      * if v == first, then it is updated in PreDestructor() */
03394     if (first->track == TRACK_BIT_DEPOT) {
03395       SetWindowDirty(WC_VEHICLE_DEPOT, first->tile);
03396     }
03397   }
03398 
03399   /* 'v' shouldn't be accessed after it has been deleted */
03400   TrackBits trackbits = v->track;
03401   TileIndex tile = v->tile;
03402   Owner owner = v->owner;
03403 
03404   delete v;
03405   v = NULL; // make sure nobody will try to read 'v' anymore
03406 
03407   if (trackbits == TRACK_BIT_WORMHOLE) {
03408     /* Vehicle is inside a wormhole, v->track contains no useful value then. */
03409     trackbits = DiagDirToDiagTrackBits(GetTunnelBridgeDirection(tile));
03410   }
03411 
03412   Track track = TrackBitsToTrack(trackbits);
03413   if (HasReservedTracks(tile, trackbits)) {
03414     UnreserveRailTrack(tile, track);
03415 
03416     /* If there are still crashed vehicles on the tile, give the track reservation to them */
03417     TrackBits remaining_trackbits = TRACK_BIT_NONE;
03418     FindVehicleOnPos(tile, &remaining_trackbits, CollectTrackbitsFromCrashedVehiclesEnum);
03419 
03420     /* It is important that these two are the first in the loop, as reservation cannot deal with every trackbit combination */
03421     assert(TRACK_BEGIN == TRACK_X && TRACK_Y == TRACK_BEGIN + 1);
03422     Track t;
03423     FOR_EACH_SET_TRACK(t, remaining_trackbits) TryReserveRailTrack(tile, t);
03424   }
03425 
03426   /* check if the wagon was on a road/rail-crossing */
03427   if (IsLevelCrossingTile(tile)) UpdateLevelCrossing(tile);
03428 
03429   /* Update signals */
03430   if (IsTileType(tile, MP_TUNNELBRIDGE) || IsRailDepotTile(tile)) {
03431     UpdateSignalsOnSegment(tile, INVALID_DIAGDIR, owner);
03432   } else {
03433     SetSignalsOnBothDir(tile, track, owner);
03434   }
03435 }
03436 
03441 static void ChangeTrainDirRandomly(Train *v)
03442 {
03443   static const DirDiff delta[] = {
03444     DIRDIFF_45LEFT, DIRDIFF_SAME, DIRDIFF_SAME, DIRDIFF_45RIGHT
03445   };
03446 
03447   do {
03448     /* We don't need to twist around vehicles if they're not visible */
03449     if (!(v->vehstatus & VS_HIDDEN)) {
03450       v->direction = ChangeDir(v->direction, delta[GB(Random(), 0, 2)]);
03451       v->UpdateDeltaXY(v->direction);
03452       v->cur_image = v->GetImage(v->direction, EIT_ON_MAP);
03453       /* Refrain from updating the z position of the vehicle when on
03454        * a bridge, because UpdateInclination() will put the vehicle under
03455        * the bridge in that case */
03456       if (v->track != TRACK_BIT_WORMHOLE) {
03457         VehicleUpdatePosition(v);
03458         v->UpdateInclination(false, false);
03459       }
03460     }
03461   } while ((v = v->Next()) != NULL);
03462 }
03463 
03469 static bool HandleCrashedTrain(Train *v)
03470 {
03471   int state = ++v->crash_anim_pos;
03472 
03473   if (state == 4 && !(v->vehstatus & VS_HIDDEN)) {
03474     CreateEffectVehicleRel(v, 4, 4, 8, EV_EXPLOSION_LARGE);
03475   }
03476 
03477   uint32 r;
03478   if (state <= 200 && Chance16R(1, 7, r)) {
03479     int index = (r * 10 >> 16);
03480 
03481     Vehicle *u = v;
03482     do {
03483       if (--index < 0) {
03484         r = Random();
03485 
03486         CreateEffectVehicleRel(u,
03487           GB(r,  8, 3) + 2,
03488           GB(r, 16, 3) + 2,
03489           GB(r,  0, 3) + 5,
03490           EV_EXPLOSION_SMALL);
03491         break;
03492       }
03493     } while ((u = u->Next()) != NULL);
03494   }
03495 
03496   if (state <= 240 && !(v->tick_counter & 3)) ChangeTrainDirRandomly(v);
03497 
03498   if (state >= 4440 && !(v->tick_counter & 0x1F)) {
03499     bool ret = v->Next() != NULL;
03500     DeleteLastWagon(v);
03501     return ret;
03502   }
03503 
03504   return true;
03505 }
03506 
03508 static const uint16 _breakdown_speeds[16] = {
03509   225, 210, 195, 180, 165, 150, 135, 120, 105, 90, 75, 60, 45, 30, 15, 15
03510 };
03511 
03512 
03521 static bool TrainApproachingLineEnd(Train *v, bool signal, bool reverse)
03522 {
03523   /* Calc position within the current tile */
03524   uint x = v->x_pos & 0xF;
03525   uint y = v->y_pos & 0xF;
03526 
03527   /* for diagonal directions, 'x' will be 0..15 -
03528    * for other directions, it will be 1, 3, 5, ..., 15 */
03529   switch (v->direction) {
03530     case DIR_N : x = ~x + ~y + 25; break;
03531     case DIR_NW: x = y;            // FALL THROUGH
03532     case DIR_NE: x = ~x + 16;      break;
03533     case DIR_E : x = ~x + y + 9;   break;
03534     case DIR_SE: x = y;            break;
03535     case DIR_S : x = x + y - 7;    break;
03536     case DIR_W : x = ~y + x + 9;   break;
03537     default: break;
03538   }
03539 
03540   /* Do not reverse when approaching red signal. Make sure the vehicle's front
03541    * does not cross the tile boundary when we do reverse, but as the vehicle's
03542    * location is based on their center, use half a vehicle's length as offset.
03543    * Multiply the half-length by two for straight directions to compensate that
03544    * we only get odd x offsets there. */
03545   if (!signal && x + (v->gcache.cached_veh_length + 1) / 2 * (IsDiagonalDirection(v->direction) ? 1 : 2) >= TILE_SIZE) {
03546     /* we are too near the tile end, reverse now */
03547     v->cur_speed = 0;
03548     if (reverse) ReverseTrainDirection(v);
03549     return false;
03550   }
03551 
03552   /* slow down */
03553   v->vehstatus |= VS_TRAIN_SLOWING;
03554   uint16 break_speed = _breakdown_speeds[x & 0xF];
03555   if (break_speed < v->cur_speed) v->cur_speed = break_speed;
03556 
03557   return true;
03558 }
03559 
03560 
03566 static bool TrainCanLeaveTile(const Train *v)
03567 {
03568   /* Exit if inside a tunnel/bridge or a depot */
03569   if (v->track == TRACK_BIT_WORMHOLE || v->track == TRACK_BIT_DEPOT) return false;
03570 
03571   TileIndex tile = v->tile;
03572 
03573   /* entering a tunnel/bridge? */
03574   if (IsTileType(tile, MP_TUNNELBRIDGE)) {
03575     DiagDirection dir = GetTunnelBridgeDirection(tile);
03576     if (DiagDirToDir(dir) == v->direction) return false;
03577   }
03578 
03579   /* entering a depot? */
03580   if (IsRailDepotTile(tile)) {
03581     DiagDirection dir = ReverseDiagDir(GetRailDepotDirection(tile));
03582     if (DiagDirToDir(dir) == v->direction) return false;
03583   }
03584 
03585   return true;
03586 }
03587 
03588 
03596 static TileIndex TrainApproachingCrossingTile(const Train *v)
03597 {
03598   assert(v->IsFrontEngine());
03599   assert(!(v->vehstatus & VS_CRASHED));
03600 
03601   if (!TrainCanLeaveTile(v)) return INVALID_TILE;
03602 
03603   DiagDirection dir = TrainExitDir(v->direction, v->track);
03604   TileIndex tile = v->tile + TileOffsByDiagDir(dir);
03605 
03606   /* not a crossing || wrong axis || unusable rail (wrong type or owner) */
03607   if (!IsLevelCrossingTile(tile) || DiagDirToAxis(dir) == GetCrossingRoadAxis(tile) ||
03608       !CheckCompatibleRail(v, tile)) {
03609     return INVALID_TILE;
03610   }
03611 
03612   return tile;
03613 }
03614 
03615 
03623 static bool TrainCheckIfLineEnds(Train *v, bool reverse)
03624 {
03625   /* First, handle broken down train */
03626 
03627   int t = v->breakdown_ctr;
03628   if (t > 1) {
03629     v->vehstatus |= VS_TRAIN_SLOWING;
03630 
03631     uint16 break_speed = _breakdown_speeds[GB(~t, 4, 4)];
03632     if (break_speed < v->cur_speed) v->cur_speed = break_speed;
03633   } else {
03634     v->vehstatus &= ~VS_TRAIN_SLOWING;
03635   }
03636 
03637   if (!TrainCanLeaveTile(v)) return true;
03638 
03639   /* Determine the non-diagonal direction in which we will exit this tile */
03640   DiagDirection dir = TrainExitDir(v->direction, v->track);
03641   /* Calculate next tile */
03642   TileIndex tile = v->tile + TileOffsByDiagDir(dir);
03643 
03644   /* Determine the track status on the next tile */
03645   TrackStatus ts = GetTileTrackStatus(tile, TRANSPORT_RAIL, 0, ReverseDiagDir(dir));
03646   TrackdirBits reachable_trackdirs = DiagdirReachesTrackdirs(dir);
03647 
03648   TrackdirBits trackdirbits = TrackStatusToTrackdirBits(ts) & reachable_trackdirs;
03649   TrackdirBits red_signals = TrackStatusToRedSignals(ts) & reachable_trackdirs;
03650 
03651   /* We are sure the train is not entering a depot, it is detected above */
03652 
03653   /* mask unreachable track bits if we are forbidden to do 90deg turns */
03654   TrackBits bits = TrackdirBitsToTrackBits(trackdirbits);
03655   if (_settings_game.pf.forbid_90_deg) {
03656     bits &= ~TrackCrossesTracks(FindFirstTrack(v->track));
03657   }
03658 
03659   /* no suitable trackbits at all || unusable rail (wrong type or owner) */
03660   if (bits == TRACK_BIT_NONE || !CheckCompatibleRail(v, tile)) {
03661     return TrainApproachingLineEnd(v, false, reverse);
03662   }
03663 
03664   /* approaching red signal */
03665   if ((trackdirbits & red_signals) != 0) return TrainApproachingLineEnd(v, true, reverse);
03666 
03667   /* approaching a rail/road crossing? then make it red */
03668   if (IsLevelCrossingTile(tile)) MaybeBarCrossingWithSound(tile);
03669 
03670   return true;
03671 }
03672 
03673 
03674 static bool TrainLocoHandler(Train *v, bool mode)
03675 {
03676   /* train has crashed? */
03677   if (v->vehstatus & VS_CRASHED) {
03678     return mode ? true : HandleCrashedTrain(v); // 'this' can be deleted here
03679   }
03680 
03681   if (v->force_proceed != TFP_NONE) {
03682     ClrBit(v->flags, VRF_TRAIN_STUCK);
03683     SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
03684   }
03685 
03686   /* train is broken down? */
03687   if (v->HandleBreakdown()) return true;
03688 
03689   if (HasBit(v->flags, VRF_REVERSING) && v->cur_speed == 0) {
03690     ReverseTrainDirection(v);
03691   }
03692 
03693   /* exit if train is stopped */
03694   if ((v->vehstatus & VS_STOPPED) && v->cur_speed == 0) return true;
03695 
03696   bool valid_order = !v->current_order.IsType(OT_NOTHING) && v->current_order.GetType() != OT_CONDITIONAL;
03697   if (ProcessOrders(v) && CheckReverseTrain(v)) {
03698     v->wait_counter = 0;
03699     v->cur_speed = 0;
03700     v->subspeed = 0;
03701     ClrBit(v->flags, VRF_LEAVING_STATION);
03702     ReverseTrainDirection(v);
03703     return true;
03704   } else if (HasBit(v->flags, VRF_LEAVING_STATION)) {
03705     /* Try to reserve a path when leaving the station as we
03706      * might not be marked as wanting a reservation, e.g.
03707      * when an overlength train gets turned around in a station. */
03708     DiagDirection dir = TrainExitDir(v->direction, v->track);
03709     if (IsRailDepotTile(v->tile) || IsTileType(v->tile, MP_TUNNELBRIDGE)) dir = INVALID_DIAGDIR;
03710 
03711     if (UpdateSignalsOnSegment(v->tile, dir, v->owner) == SIGSEG_PBS || _settings_game.pf.reserve_paths) {
03712       TryPathReserve(v, true, true);
03713     }
03714     ClrBit(v->flags, VRF_LEAVING_STATION);
03715   }
03716 
03717   v->HandleLoading(mode);
03718 
03719   if (v->current_order.IsType(OT_LOADING)) return true;
03720 
03721   if (CheckTrainStayInDepot(v)) return true;
03722 
03723   if (!mode) v->ShowVisualEffect();
03724 
03725   /* We had no order but have an order now, do look ahead. */
03726   if (!valid_order && !v->current_order.IsType(OT_NOTHING)) {
03727     CheckNextTrainTile(v);
03728   }
03729 
03730   /* Handle stuck trains. */
03731   if (!mode && HasBit(v->flags, VRF_TRAIN_STUCK)) {
03732     ++v->wait_counter;
03733 
03734     /* Should we try reversing this tick if still stuck? */
03735     bool turn_around = v->wait_counter % (_settings_game.pf.wait_for_pbs_path * DAY_TICKS) == 0 && _settings_game.pf.reverse_at_signals;
03736 
03737     if (!turn_around && v->wait_counter % _settings_game.pf.path_backoff_interval != 0 && v->force_proceed == TFP_NONE) return true;
03738     if (!TryPathReserve(v)) {
03739       /* Still stuck. */
03740       if (turn_around) ReverseTrainDirection(v);
03741 
03742       if (HasBit(v->flags, VRF_TRAIN_STUCK) && v->wait_counter > 2 * _settings_game.pf.wait_for_pbs_path * DAY_TICKS) {
03743         /* Show message to player. */
03744         if (_settings_client.gui.lost_vehicle_warn && v->owner == _local_company) {
03745           SetDParam(0, v->index);
03746           AddVehicleNewsItem(
03747             STR_NEWS_TRAIN_IS_STUCK,
03748             NS_ADVICE,
03749             v->index
03750           );
03751         }
03752         v->wait_counter = 0;
03753       }
03754       /* Exit if force proceed not pressed, else reset stuck flag anyway. */
03755       if (v->force_proceed == TFP_NONE) return true;
03756       ClrBit(v->flags, VRF_TRAIN_STUCK);
03757       v->wait_counter = 0;
03758       SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
03759     }
03760   }
03761 
03762   if (v->current_order.IsType(OT_LEAVESTATION)) {
03763     v->current_order.Free();
03764     SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
03765     return true;
03766   }
03767 
03768   int j = v->UpdateSpeed();
03769 
03770   /* we need to invalidate the widget if we are stopping from 'Stopping 0 km/h' to 'Stopped' */
03771   if (v->cur_speed == 0 && (v->vehstatus & VS_STOPPED)) {
03772     /* If we manually stopped, we're not force-proceeding anymore. */
03773     v->force_proceed = TFP_NONE;
03774     SetWindowDirty(WC_VEHICLE_VIEW, v->index);
03775   }
03776 
03777   int adv_spd = v->GetAdvanceDistance();
03778   if (j < adv_spd) {
03779     /* if the vehicle has speed 0, update the last_speed field. */
03780     if (v->cur_speed == 0) v->SetLastSpeed();
03781   } else {
03782     TrainCheckIfLineEnds(v);
03783     /* Loop until the train has finished moving. */
03784     for (;;) {
03785       j -= adv_spd;
03786       TrainController(v, NULL);
03787       /* Don't continue to move if the train crashed. */
03788       if (CheckTrainCollision(v)) break;
03789       /* Determine distance to next map position */
03790       adv_spd = v->GetAdvanceDistance();
03791 
03792       /* No more moving this tick */
03793       if (j < adv_spd || v->cur_speed == 0) break;
03794 
03795       OrderType order_type = v->current_order.GetType();
03796       /* Do not skip waypoints (incl. 'via' stations) when passing through at full speed. */
03797       if ((order_type == OT_GOTO_WAYPOINT || order_type == OT_GOTO_STATION) &&
03798             (v->current_order.GetNonStopType() & ONSF_NO_STOP_AT_DESTINATION_STATION) &&
03799             IsTileType(v->tile, MP_STATION) &&
03800             v->current_order.GetDestination() == GetStationIndex(v->tile)) {
03801         ProcessOrders(v);
03802       }
03803     }
03804     v->SetLastSpeed();
03805   }
03806 
03807   for (Train *u = v; u != NULL; u = u->Next()) {
03808     if ((u->vehstatus & VS_HIDDEN) != 0) continue;
03809 
03810     u->UpdateViewport(false, false);
03811   }
03812 
03813   if (v->progress == 0) v->progress = j; // Save unused spd for next time, if TrainController didn't set progress
03814 
03815   return true;
03816 }
03817 
03822 Money Train::GetRunningCost() const
03823 {
03824   Money cost = 0;
03825   const Train *v = this;
03826 
03827   do {
03828     const Engine *e = v->GetEngine();
03829     if (e->u.rail.running_cost_class == INVALID_PRICE) continue;
03830 
03831     uint cost_factor = GetVehicleProperty(v, PROP_TRAIN_RUNNING_COST_FACTOR, e->u.rail.running_cost);
03832     if (cost_factor == 0) continue;
03833 
03834     /* Halve running cost for multiheaded parts */
03835     if (v->IsMultiheaded()) cost_factor /= 2;
03836 
03837     cost += GetPrice(e->u.rail.running_cost_class, cost_factor, e->GetGRF());
03838   } while ((v = v->GetNextVehicle()) != NULL);
03839 
03840   return cost;
03841 }
03842 
03847 bool Train::Tick()
03848 {
03849   this->tick_counter++;
03850 
03851   if (this->IsFrontEngine()) {
03852     if (!(this->vehstatus & VS_STOPPED) || this->cur_speed > 0) this->running_ticks++;
03853 
03854     this->current_order_time++;
03855 
03856     if (!TrainLocoHandler(this, false)) return false;
03857 
03858     return TrainLocoHandler(this, true);
03859   } else if (this->IsFreeWagon() && (this->vehstatus & VS_CRASHED)) {
03860     /* Delete flooded standalone wagon chain */
03861     if (++this->crash_anim_pos >= 4400) {
03862       delete this;
03863       return false;
03864     }
03865   }
03866 
03867   return true;
03868 }
03869 
03874 static void CheckIfTrainNeedsService(Train *v)
03875 {
03876   if (Company::Get(v->owner)->settings.vehicle.servint_trains == 0 || !v->NeedsAutomaticServicing()) return;
03877   if (v->IsChainInDepot()) {
03878     VehicleServiceInDepot(v);
03879     return;
03880   }
03881 
03882   uint max_penalty;
03883   switch (_settings_game.pf.pathfinder_for_trains) {
03884     case VPF_NPF:  max_penalty = _settings_game.pf.npf.maximum_go_to_depot_penalty;  break;
03885     case VPF_YAPF: max_penalty = _settings_game.pf.yapf.maximum_go_to_depot_penalty; break;
03886     default: NOT_REACHED();
03887   }
03888 
03889   FindDepotData tfdd = FindClosestTrainDepot(v, max_penalty);
03890   /* Only go to the depot if it is not too far out of our way. */
03891   if (tfdd.best_length == UINT_MAX || tfdd.best_length > max_penalty) {
03892     if (v->current_order.IsType(OT_GOTO_DEPOT)) {
03893       /* If we were already heading for a depot but it has
03894        * suddenly moved farther away, we continue our normal
03895        * schedule? */
03896       v->current_order.MakeDummy();
03897       SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
03898     }
03899     return;
03900   }
03901 
03902   DepotID depot = GetDepotIndex(tfdd.tile);
03903 
03904   if (v->current_order.IsType(OT_GOTO_DEPOT) &&
03905       v->current_order.GetDestination() != depot &&
03906       !Chance16(3, 16)) {
03907     return;
03908   }
03909 
03910   SetBit(v->gv_flags, GVF_SUPPRESS_IMPLICIT_ORDERS);
03911   v->current_order.MakeGoToDepot(depot, ODTFB_SERVICE);
03912   v->dest_tile = tfdd.tile;
03913   SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
03914 }
03915 
03917 void Train::OnNewDay()
03918 {
03919   AgeVehicle(this);
03920 
03921   if ((++this->day_counter & 7) == 0) DecreaseVehicleValue(this);
03922 
03923   if (this->IsFrontEngine()) {
03924     CheckVehicleBreakdown(this);
03925 
03926     CheckIfTrainNeedsService(this);
03927 
03928     CheckOrders(this);
03929 
03930     /* update destination */
03931     if (this->current_order.IsType(OT_GOTO_STATION)) {
03932       TileIndex tile = Station::Get(this->current_order.GetDestination())->train_station.tile;
03933       if (tile != INVALID_TILE) this->dest_tile = tile;
03934     }
03935 
03936     if (this->running_ticks != 0) {
03937       /* running costs */
03938       CommandCost cost(EXPENSES_TRAIN_RUN, this->GetRunningCost() * this->running_ticks / (DAYS_IN_YEAR  * DAY_TICKS));
03939 
03940       this->profit_this_year -= cost.GetCost();
03941       this->running_ticks = 0;
03942 
03943       SubtractMoneyFromCompanyFract(this->owner, cost);
03944 
03945       SetWindowDirty(WC_VEHICLE_DETAILS, this->index);
03946       SetWindowClassesDirty(WC_TRAINS_LIST);
03947     }
03948   }
03949 }
03950 
03955 Trackdir Train::GetVehicleTrackdir() const
03956 {
03957   if (this->vehstatus & VS_CRASHED) return INVALID_TRACKDIR;
03958 
03959   if (this->track == TRACK_BIT_DEPOT) {
03960     /* We'll assume the train is facing outwards */
03961     return DiagDirToDiagTrackdir(GetRailDepotDirection(this->tile)); // Train in depot
03962   }
03963 
03964   if (this->track == TRACK_BIT_WORMHOLE) {
03965     /* train in tunnel or on bridge, so just use his direction and assume a diagonal track */
03966     return DiagDirToDiagTrackdir(DirToDiagDir(this->direction));
03967   }
03968 
03969   return TrackDirectionToTrackdir(FindFirstTrack(this->track), this->direction);
03970 }