train_cmd.cpp

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00001 /* $Id: train_cmd.cpp 15497 2009-02-16 17:16:58Z smatz $ */
00002 
00005 #include "stdafx.h"
00006 #include "gui.h"
00007 #include "articulated_vehicles.h"
00008 #include "command_func.h"
00009 #include "npf.h"
00010 #include "news_func.h"
00011 #include "engine_func.h"
00012 #include "engine_base.h"
00013 #include "company_func.h"
00014 #include "depot_base.h"
00015 #include "vehicle_gui.h"
00016 #include "train.h"
00017 #include "newgrf_engine.h"
00018 #include "newgrf_sound.h"
00019 #include "newgrf_text.h"
00020 #include "yapf/follow_track.hpp"
00021 #include "group.h"
00022 #include "table/sprites.h"
00023 #include "strings_func.h"
00024 #include "functions.h"
00025 #include "window_func.h"
00026 #include "vehicle_func.h"
00027 #include "sound_func.h"
00028 #include "variables.h"
00029 #include "autoreplace_gui.h"
00030 #include "gfx_func.h"
00031 #include "ai/ai.hpp"
00032 #include "newgrf_station.h"
00033 #include "effectvehicle_func.h"
00034 #include "gamelog.h"
00035 #include "network/network.h"
00036 
00037 #include "table/strings.h"
00038 #include "table/train_cmd.h"
00039 
00040 static Track ChooseTrainTrack(Vehicle *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks, bool force_res, bool *got_reservation, bool mark_stuck);
00041 static bool TrainCheckIfLineEnds(Vehicle *v);
00042 static void TrainController(Vehicle *v, Vehicle *nomove, bool update_image);
00043 static TileIndex TrainApproachingCrossingTile(const Vehicle *v);
00044 static void CheckIfTrainNeedsService(Vehicle *v);
00045 static void CheckNextTrainTile(Vehicle *v);
00046 
00047 static const byte _vehicle_initial_x_fract[4] = {10, 8, 4,  8};
00048 static const byte _vehicle_initial_y_fract[4] = { 8, 4, 8, 10};
00049 
00050 
00058 static inline DiagDirection TrainExitDir(Direction direction, TrackBits track)
00059 {
00060   static const TrackBits state_dir_table[DIAGDIR_END] = { TRACK_BIT_RIGHT, TRACK_BIT_LOWER, TRACK_BIT_LEFT, TRACK_BIT_UPPER };
00061 
00062   DiagDirection diagdir = DirToDiagDir(direction);
00063 
00064   /* Determine the diagonal direction in which we will exit this tile */
00065   if (!HasBit(direction, 0) && track != state_dir_table[diagdir]) {
00066     diagdir = ChangeDiagDir(diagdir, DIAGDIRDIFF_90LEFT);
00067   }
00068 
00069   return diagdir;
00070 }
00071 
00072 
00077 byte FreightWagonMult(CargoID cargo)
00078 {
00079   if (!GetCargo(cargo)->is_freight) return 1;
00080   return _settings_game.vehicle.freight_trains;
00081 }
00082 
00083 
00088 void TrainPowerChanged(Vehicle *v)
00089 {
00090   uint32 total_power = 0;
00091   uint32 max_te = 0;
00092 
00093   for (const Vehicle *u = v; u != NULL; u = u->Next()) {
00094     RailType railtype = GetRailType(u->tile);
00095 
00096     /* Power is not added for articulated parts */
00097     if (!IsArticulatedPart(u)) {
00098       bool engine_has_power = HasPowerOnRail(u->u.rail.railtype, railtype);
00099 
00100       const RailVehicleInfo *rvi_u = RailVehInfo(u->engine_type);
00101 
00102       if (engine_has_power) {
00103         uint16 power = GetVehicleProperty(u, 0x0B, rvi_u->power);
00104         if (power != 0) {
00105           /* Halve power for multiheaded parts */
00106           if (IsMultiheaded(u)) power /= 2;
00107 
00108           total_power += power;
00109           /* Tractive effort in (tonnes * 1000 * 10 =) N */
00110           max_te += (u->u.rail.cached_veh_weight * 10000 * GetVehicleProperty(u, 0x1F, rvi_u->tractive_effort)) / 256;
00111         }
00112       }
00113     }
00114 
00115     if (HasBit(u->u.rail.flags, VRF_POWEREDWAGON) && HasPowerOnRail(v->u.rail.railtype, railtype)) {
00116       total_power += RailVehInfo(u->u.rail.first_engine)->pow_wag_power;
00117     }
00118   }
00119 
00120   if (v->u.rail.cached_power != total_power || v->u.rail.cached_max_te != max_te) {
00121     /* If it has no power (no catenary), stop the train */
00122     if (total_power == 0) v->vehstatus |= VS_STOPPED;
00123 
00124     v->u.rail.cached_power = total_power;
00125     v->u.rail.cached_max_te = max_te;
00126     InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
00127     InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
00128   }
00129 }
00130 
00131 
00137 static void TrainCargoChanged(Vehicle *v)
00138 {
00139   uint32 weight = 0;
00140 
00141   for (Vehicle *u = v; u != NULL; u = u->Next()) {
00142     uint32 vweight = GetCargo(u->cargo_type)->weight * u->cargo.Count() * FreightWagonMult(u->cargo_type) / 16;
00143 
00144     /* Vehicle weight is not added for articulated parts. */
00145     if (!IsArticulatedPart(u)) {
00146       /* vehicle weight is the sum of the weight of the vehicle and the weight of its cargo */
00147       vweight += GetVehicleProperty(u, 0x16, RailVehInfo(u->engine_type)->weight);
00148     }
00149 
00150     /* powered wagons have extra weight added */
00151     if (HasBit(u->u.rail.flags, VRF_POWEREDWAGON)) {
00152       vweight += RailVehInfo(u->u.rail.first_engine)->pow_wag_weight;
00153     }
00154 
00155     /* consist weight is the sum of the weight of all vehicles in the consist */
00156     weight += vweight;
00157 
00158     /* store vehicle weight in cache */
00159     u->u.rail.cached_veh_weight = vweight;
00160   }
00161 
00162   /* store consist weight in cache */
00163   v->u.rail.cached_weight = weight;
00164 
00165   /* Now update train power (tractive effort is dependent on weight) */
00166   TrainPowerChanged(v);
00167 }
00168 
00169 
00174 static void RailVehicleLengthChanged(const Vehicle *u)
00175 {
00176   /* show a warning once for each engine in whole game and once for each GRF after each game load */
00177   const Engine *engine = GetEngine(u->engine_type);
00178   uint32 grfid = engine->grffile->grfid;
00179   GRFConfig *grfconfig = GetGRFConfig(grfid);
00180   if (GamelogGRFBugReverse(grfid, engine->internal_id) || !HasBit(grfconfig->grf_bugs, GBUG_VEH_LENGTH)) {
00181     SetBit(grfconfig->grf_bugs, GBUG_VEH_LENGTH);
00182     SetDParamStr(0, grfconfig->name);
00183     SetDParam(1, u->engine_type);
00184     ShowErrorMessage(STR_NEWGRF_BROKEN_VEHICLE_LENGTH, STR_NEWGRF_BROKEN, 0, 0);
00185 
00186     /* debug output */
00187     char buffer[512];
00188 
00189     SetDParamStr(0, grfconfig->name);
00190     GetString(buffer, STR_NEWGRF_BROKEN, lastof(buffer));
00191     DEBUG(grf, 0, "%s", buffer + 3);
00192 
00193     SetDParam(1, u->engine_type);
00194     GetString(buffer, STR_NEWGRF_BROKEN_VEHICLE_LENGTH, lastof(buffer));
00195     DEBUG(grf, 0, "%s", buffer + 3);
00196 
00197     if (!_networking) _pause_game = -1;
00198   }
00199 }
00200 
00202 void CheckTrainsLengths()
00203 {
00204   const Vehicle *v;
00205 
00206   FOR_ALL_VEHICLES(v) {
00207     if (v->type == VEH_TRAIN && v->First() == v && !(v->vehstatus & VS_CRASHED)) {
00208       for (const Vehicle *u = v, *w = v->Next(); w != NULL; u = w, w = w->Next()) {
00209         if (u->u.rail.track != TRACK_BIT_DEPOT) {
00210           if ((w->u.rail.track != TRACK_BIT_DEPOT &&
00211               max(abs(u->x_pos - w->x_pos), abs(u->y_pos - w->y_pos)) != u->u.rail.cached_veh_length) ||
00212               (w->u.rail.track == TRACK_BIT_DEPOT && TicksToLeaveDepot(u) <= 0)) {
00213             SetDParam(0, v->index);
00214             SetDParam(1, v->owner);
00215             ShowErrorMessage(INVALID_STRING_ID, STR_BROKEN_VEHICLE_LENGTH, 0, 0);
00216 
00217             if (!_networking) _pause_game = -1;
00218           }
00219         }
00220       }
00221     }
00222   }
00223 }
00224 
00232 void TrainConsistChanged(Vehicle *v, bool same_length)
00233 {
00234   uint16 max_speed = UINT16_MAX;
00235 
00236   assert(v->type == VEH_TRAIN);
00237   assert(IsFrontEngine(v) || IsFreeWagon(v));
00238 
00239   const RailVehicleInfo *rvi_v = RailVehInfo(v->engine_type);
00240   EngineID first_engine = IsFrontEngine(v) ? v->engine_type : INVALID_ENGINE;
00241   v->u.rail.cached_total_length = 0;
00242   v->u.rail.compatible_railtypes = RAILTYPES_NONE;
00243 
00244   bool train_can_tilt = true;
00245 
00246   for (Vehicle *u = v; u != NULL; u = u->Next()) {
00247     const RailVehicleInfo *rvi_u = RailVehInfo(u->engine_type);
00248 
00249     /* Check the v->first cache. */
00250     assert(u->First() == v);
00251 
00252     /* update the 'first engine' */
00253     u->u.rail.first_engine = v == u ? INVALID_ENGINE : first_engine;
00254     u->u.rail.railtype = rvi_u->railtype;
00255 
00256     if (IsTrainEngine(u)) first_engine = u->engine_type;
00257 
00258     /* Set user defined data to its default value */
00259     u->u.rail.user_def_data = rvi_u->user_def_data;
00260   }
00261 
00262   for (Vehicle *u = v; u != NULL; u = u->Next()) {
00263     /* Update user defined data (must be done before other properties) */
00264     u->u.rail.user_def_data = GetVehicleProperty(u, 0x25, u->u.rail.user_def_data);
00265   }
00266 
00267   for (Vehicle *u = v; u != NULL; u = u->Next()) {
00268     const RailVehicleInfo *rvi_u = RailVehInfo(u->engine_type);
00269 
00270     if (!HasBit(EngInfo(u->engine_type)->misc_flags, EF_RAIL_TILTS)) train_can_tilt = false;
00271 
00272     /* Cache wagon override sprite group. NULL is returned if there is none */
00273     u->u.rail.cached_override = GetWagonOverrideSpriteSet(u->engine_type, u->cargo_type, u->u.rail.first_engine);
00274 
00275     /* Reset colour map */
00276     u->colourmap = PAL_NONE;
00277 
00278     if (rvi_u->visual_effect != 0) {
00279       u->u.rail.cached_vis_effect = rvi_u->visual_effect;
00280     } else {
00281       if (IsTrainWagon(u) || IsArticulatedPart(u)) {
00282         /* Wagons and articulated parts have no effect by default */
00283         u->u.rail.cached_vis_effect = 0x40;
00284       } else if (rvi_u->engclass == 0) {
00285         /* Steam is offset by -4 units */
00286         u->u.rail.cached_vis_effect = 4;
00287       } else {
00288         /* Diesel fumes and sparks come from the centre */
00289         u->u.rail.cached_vis_effect = 8;
00290       }
00291     }
00292 
00293     /* Check powered wagon / visual effect callback */
00294     if (HasBit(EngInfo(u->engine_type)->callbackmask, CBM_TRAIN_WAGON_POWER)) {
00295       uint16 callback = GetVehicleCallback(CBID_TRAIN_WAGON_POWER, 0, 0, u->engine_type, u);
00296 
00297       if (callback != CALLBACK_FAILED) u->u.rail.cached_vis_effect = GB(callback, 0, 8);
00298     }
00299 
00300     if (rvi_v->pow_wag_power != 0 && rvi_u->railveh_type == RAILVEH_WAGON &&
00301       UsesWagonOverride(u) && !HasBit(u->u.rail.cached_vis_effect, 7)) {
00302       /* wagon is powered */
00303       SetBit(u->u.rail.flags, VRF_POWEREDWAGON); // cache 'powered' status
00304     } else {
00305       ClrBit(u->u.rail.flags, VRF_POWEREDWAGON);
00306     }
00307 
00308     if (!IsArticulatedPart(u)) {
00309       /* Do not count powered wagons for the compatible railtypes, as wagons always
00310          have railtype normal */
00311       if (rvi_u->power > 0) {
00312         v->u.rail.compatible_railtypes |= GetRailTypeInfo(u->u.rail.railtype)->powered_railtypes;
00313       }
00314 
00315       /* Some electric engines can be allowed to run on normal rail. It happens to all
00316        * existing electric engines when elrails are disabled and then re-enabled */
00317       if (HasBit(u->u.rail.flags, VRF_EL_ENGINE_ALLOWED_NORMAL_RAIL)) {
00318         u->u.rail.railtype = RAILTYPE_RAIL;
00319         u->u.rail.compatible_railtypes |= RAILTYPES_RAIL;
00320       }
00321 
00322       /* max speed is the minimum of the speed limits of all vehicles in the consist */
00323       if ((rvi_u->railveh_type != RAILVEH_WAGON || _settings_game.vehicle.wagon_speed_limits) && !UsesWagonOverride(u)) {
00324         uint16 speed = GetVehicleProperty(u, 0x09, rvi_u->max_speed);
00325         if (speed != 0) max_speed = min(speed, max_speed);
00326       }
00327     }
00328 
00329     if (u->cargo_type == rvi_u->cargo_type && u->cargo_subtype == 0) {
00330       /* Set cargo capacity if we've not been refitted */
00331       u->cargo_cap = GetVehicleProperty(u, 0x14, rvi_u->capacity);
00332     }
00333 
00334     /* check the vehicle length (callback) */
00335     uint16 veh_len = CALLBACK_FAILED;
00336     if (HasBit(EngInfo(u->engine_type)->callbackmask, CBM_VEHICLE_LENGTH)) {
00337       veh_len = GetVehicleCallback(CBID_VEHICLE_LENGTH, 0, 0, u->engine_type, u);
00338     }
00339     if (veh_len == CALLBACK_FAILED) veh_len = rvi_u->shorten_factor;
00340     veh_len = 8 - Clamp(veh_len, 0, u->Next() == NULL ? 7 : 5); // the clamp on vehicles not the last in chain is stricter, as too short wagons can break the 'follow next vehicle' code
00341 
00342     /* verify length hasn't changed */
00343     if (same_length && veh_len != u->u.rail.cached_veh_length) RailVehicleLengthChanged(u);
00344 
00345     /* update vehicle length? */
00346     if (!same_length) u->u.rail.cached_veh_length = veh_len;
00347 
00348     v->u.rail.cached_total_length += u->u.rail.cached_veh_length;
00349   }
00350 
00351   /* store consist weight/max speed in cache */
00352   v->u.rail.cached_max_speed = max_speed;
00353   v->u.rail.cached_tilt = train_can_tilt;
00354 
00355   /* 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) */
00356   TrainCargoChanged(v);
00357 
00358   if (IsFrontEngine(v)) {
00359     UpdateTrainAcceleration(v);
00360     InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
00361   }
00362 }
00363 
00364 enum AccelType {
00365   AM_ACCEL,
00366   AM_BRAKE
00367 };
00368 
00370 static int GetTrainAcceleration(Vehicle *v, bool mode)
00371 {
00372   static const int absolute_max_speed = UINT16_MAX;
00373   int max_speed = absolute_max_speed;
00374   int speed = v->cur_speed * 10 / 16; // km-ish/h -> mp/h
00375   int curvecount[2] = {0, 0};
00376 
00377   /*first find the curve speed limit */
00378   int numcurve = 0;
00379   int sum = 0;
00380   int pos = 0;
00381   int lastpos = -1;
00382   for (const Vehicle *u = v; u->Next() != NULL; u = u->Next(), pos++) {
00383     Direction this_dir = u->direction;
00384     Direction next_dir = u->Next()->direction;
00385 
00386     DirDiff dirdiff = DirDifference(this_dir, next_dir);
00387     if (dirdiff == DIRDIFF_SAME) continue;
00388 
00389     if (dirdiff == DIRDIFF_45LEFT) curvecount[0]++;
00390     if (dirdiff == DIRDIFF_45RIGHT) curvecount[1]++;
00391     if (dirdiff == DIRDIFF_45LEFT || dirdiff == DIRDIFF_45RIGHT) {
00392       if (lastpos != -1) {
00393         numcurve++;
00394         sum += pos - lastpos;
00395         if (pos - lastpos == 1) {
00396           max_speed = 88;
00397         }
00398       }
00399       lastpos = pos;
00400     }
00401 
00402     /*if we have a 90 degree turn, fix the speed limit to 60 */
00403     if (dirdiff == DIRDIFF_90LEFT || dirdiff == DIRDIFF_90RIGHT) {
00404       max_speed = 61;
00405     }
00406   }
00407 
00408   if ((curvecount[0] != 0 || curvecount[1] != 0) && max_speed > 88) {
00409     int total = curvecount[0] + curvecount[1];
00410 
00411     if (curvecount[0] == 1 && curvecount[1] == 1) {
00412       max_speed = absolute_max_speed;
00413     } else if (total > 1) {
00414       if (numcurve > 0) sum /= numcurve;
00415       max_speed = 232 - (13 - Clamp(sum, 1, 12)) * (13 - Clamp(sum, 1, 12));
00416     }
00417   }
00418 
00419   if (max_speed != absolute_max_speed) {
00420     /* Apply the engine's rail type curve speed advantage, if it slowed by curves */
00421     const RailtypeInfo *rti = GetRailTypeInfo(v->u.rail.railtype);
00422     max_speed += (max_speed / 2) * rti->curve_speed;
00423 
00424     if (v->u.rail.cached_tilt) {
00425       /* Apply max_speed bonus of 20% for a tilting train */
00426       max_speed += max_speed / 5;
00427     }
00428   }
00429 
00430   if (IsTileType(v->tile, MP_STATION) && IsFrontEngine(v)) {
00431     if (v->current_order.ShouldStopAtStation(v, GetStationIndex(v->tile))) {
00432       int station_length = GetStationByTile(v->tile)->GetPlatformLength(v->tile, DirToDiagDir(v->direction));
00433 
00434       int st_max_speed = 120;
00435 
00436       int delta_v = v->cur_speed / (station_length + 1);
00437       if (v->max_speed > (v->cur_speed - delta_v)) {
00438         st_max_speed = v->cur_speed - (delta_v / 10);
00439       }
00440 
00441       st_max_speed = max(st_max_speed, 25 * station_length);
00442       max_speed = min(max_speed, st_max_speed);
00443     }
00444   }
00445 
00446   int mass = v->u.rail.cached_weight;
00447   int power = v->u.rail.cached_power * 746;
00448   max_speed = min(max_speed, v->u.rail.cached_max_speed);
00449 
00450   int num = 0; //number of vehicles, change this into the number of axles later
00451   int incl = 0;
00452   int drag_coeff = 20; //[1e-4]
00453   for (const Vehicle *u = v; u != NULL; u = u->Next()) {
00454     num++;
00455     drag_coeff += 3;
00456 
00457     if (u->u.rail.track == TRACK_BIT_DEPOT) max_speed = min(max_speed, 61);
00458 
00459     if (HasBit(u->u.rail.flags, VRF_GOINGUP)) {
00460       incl += u->u.rail.cached_veh_weight * 60; //3% slope, quite a bit actually
00461     } else if (HasBit(u->u.rail.flags, VRF_GOINGDOWN)) {
00462       incl -= u->u.rail.cached_veh_weight * 60;
00463     }
00464   }
00465 
00466   v->max_speed = max_speed;
00467 
00468   const int area = 120;
00469   const int friction = 35; //[1e-3]
00470   int resistance;
00471   if (v->u.rail.railtype != RAILTYPE_MAGLEV) {
00472     resistance = 13 * mass / 10;
00473     resistance += 60 * num;
00474     resistance += friction * mass * speed / 1000;
00475     resistance += (area * drag_coeff * speed * speed) / 10000;
00476   } else {
00477     resistance = (area * (drag_coeff / 2) * speed * speed) / 10000;
00478   }
00479   resistance += incl;
00480   resistance *= 4; //[N]
00481 
00482   const int max_te = v->u.rail.cached_max_te; // [N]
00483   int force;
00484   if (speed > 0) {
00485     switch (v->u.rail.railtype) {
00486       case RAILTYPE_RAIL:
00487       case RAILTYPE_ELECTRIC:
00488       case RAILTYPE_MONO:
00489         force = power / speed; //[N]
00490         force *= 22;
00491         force /= 10;
00492         if (mode == AM_ACCEL && force > max_te) force = max_te;
00493         break;
00494 
00495       default: NOT_REACHED();
00496       case RAILTYPE_MAGLEV:
00497         force = power / 25;
00498         break;
00499     }
00500   } else {
00501     /* "kickoff" acceleration */
00502     force = (mode == AM_ACCEL && v->u.rail.railtype != RAILTYPE_MAGLEV) ? min(max_te, power) : power;
00503     force = max(force, (mass * 8) + resistance);
00504   }
00505 
00506   if (mode == AM_ACCEL) {
00507     return (force - resistance) / (mass * 2);
00508   } else {
00509     return min(-force - resistance, -10000) / mass;
00510   }
00511 }
00512 
00513 void UpdateTrainAcceleration(Vehicle *v)
00514 {
00515   assert(IsFrontEngine(v));
00516 
00517   v->max_speed = v->u.rail.cached_max_speed;
00518 
00519   uint power = v->u.rail.cached_power;
00520   uint weight = v->u.rail.cached_weight;
00521   assert(weight != 0);
00522   v->acceleration = Clamp(power / weight * 4, 1, 255);
00523 }
00524 
00525 SpriteID Train::GetImage(Direction direction) const
00526 {
00527   uint8 spritenum = this->spritenum;
00528   SpriteID sprite;
00529 
00530   if (HasBit(this->u.rail.flags, VRF_REVERSE_DIRECTION)) direction = ReverseDir(direction);
00531 
00532   if (is_custom_sprite(spritenum)) {
00533     sprite = GetCustomVehicleSprite(this, (Direction)(direction + 4 * IS_CUSTOM_SECONDHEAD_SPRITE(spritenum)));
00534     if (sprite != 0) return sprite;
00535 
00536     spritenum = GetEngine(this->engine_type)->image_index;
00537   }
00538 
00539   sprite = _engine_sprite_base[spritenum] + ((direction + _engine_sprite_add[spritenum]) & _engine_sprite_and[spritenum]);
00540 
00541   if (this->cargo.Count() >= this->cargo_cap / 2U) sprite += _wagon_full_adder[spritenum];
00542 
00543   return sprite;
00544 }
00545 
00546 static SpriteID GetRailIcon(EngineID engine, bool rear_head, int &y)
00547 {
00548   Direction dir = rear_head ? DIR_E : DIR_W;
00549   uint8 spritenum = RailVehInfo(engine)->image_index;
00550 
00551   if (is_custom_sprite(spritenum)) {
00552     SpriteID sprite = GetCustomVehicleIcon(engine, dir);
00553     if (sprite != 0) {
00554       y += _traininfo_vehicle_pitch; // TODO Make this per-GRF
00555       return sprite;
00556     }
00557 
00558     spritenum = GetEngine(engine)->image_index;
00559   }
00560 
00561   if (rear_head) spritenum++;
00562 
00563   return ((6 + _engine_sprite_add[spritenum]) & _engine_sprite_and[spritenum]) + _engine_sprite_base[spritenum];
00564 }
00565 
00566 void DrawTrainEngine(int x, int y, EngineID engine, SpriteID pal)
00567 {
00568   if (RailVehInfo(engine)->railveh_type == RAILVEH_MULTIHEAD) {
00569     int yf = y;
00570     int yr = y;
00571 
00572     SpriteID spritef = GetRailIcon(engine, false, yf);
00573     SpriteID spriter = GetRailIcon(engine, true, yr);
00574     DrawSprite(spritef, pal, x - 14, yf);
00575     DrawSprite(spriter, pal, x + 15, yr);
00576   } else {
00577     SpriteID sprite = GetRailIcon(engine, false, y);
00578     DrawSprite(sprite, pal, x, y);
00579   }
00580 }
00581 
00582 static CommandCost CmdBuildRailWagon(EngineID engine, TileIndex tile, DoCommandFlag flags)
00583 {
00584   const RailVehicleInfo *rvi = RailVehInfo(engine);
00585   CommandCost value(EXPENSES_NEW_VEHICLES, GetEngine(engine)->GetCost());
00586 
00587   if (flags & DC_QUERY_COST) return value;
00588 
00589   /* Check that the wagon can drive on the track in question */
00590   if (!IsCompatibleRail(rvi->railtype, GetRailType(tile))) return CMD_ERROR;
00591 
00592   uint num_vehicles = 1 + CountArticulatedParts(engine, false);
00593 
00594   /* Allow for the wagon and the articulated parts, plus one to "terminate" the list. */
00595   Vehicle **vl = AllocaM(Vehicle*, num_vehicles + 1);
00596   memset(vl, 0, sizeof(*vl) * (num_vehicles + 1));
00597 
00598   if (!Vehicle::AllocateList(vl, num_vehicles)) {
00599     return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);
00600   }
00601 
00602   if (flags & DC_EXEC) {
00603     Vehicle *v = vl[0];
00604     v->spritenum = rvi->image_index;
00605 
00606     Vehicle *u = NULL;
00607 
00608     Vehicle *w;
00609     FOR_ALL_VEHICLES(w) {
00610       if (w->type == VEH_TRAIN && w->tile == tile &&
00611           IsFreeWagon(w) && w->engine_type == engine &&
00612           !HASBITS(w->vehstatus, VS_CRASHED)) {          
00613         u = GetLastVehicleInChain(w);
00614         break;
00615       }
00616     }
00617 
00618     v = new (v) Train();
00619     v->engine_type = engine;
00620 
00621     DiagDirection dir = GetRailDepotDirection(tile);
00622 
00623     v->direction = DiagDirToDir(dir);
00624     v->tile = tile;
00625 
00626     int x = TileX(tile) * TILE_SIZE | _vehicle_initial_x_fract[dir];
00627     int y = TileY(tile) * TILE_SIZE | _vehicle_initial_y_fract[dir];
00628 
00629     v->x_pos = x;
00630     v->y_pos = y;
00631     v->z_pos = GetSlopeZ(x, y);
00632     v->owner = _current_company;
00633     v->u.rail.track = TRACK_BIT_DEPOT;
00634     v->vehstatus = VS_HIDDEN | VS_DEFPAL;
00635 
00636 //    v->subtype = 0;
00637     SetTrainWagon(v);
00638 
00639     if (u != NULL) {
00640       u->SetNext(v);
00641     } else {
00642       SetFreeWagon(v);
00643       InvalidateWindowData(WC_VEHICLE_DEPOT, v->tile);
00644     }
00645 
00646     v->cargo_type = rvi->cargo_type;
00647 //    v->cargo_subtype = 0;
00648     v->cargo_cap = rvi->capacity;
00649     v->value = value.GetCost();
00650 //    v->day_counter = 0;
00651 
00652     v->u.rail.railtype = rvi->railtype;
00653 
00654     v->build_year = _cur_year;
00655     v->cur_image = 0xAC2;
00656     v->random_bits = VehicleRandomBits();
00657 
00658     v->group_id = DEFAULT_GROUP;
00659 
00660     AddArticulatedParts(vl, VEH_TRAIN);
00661 
00662     _new_vehicle_id = v->index;
00663 
00664     VehiclePositionChanged(v);
00665     TrainConsistChanged(v->First(), false);
00666     UpdateTrainGroupID(v->First());
00667 
00668     InvalidateWindow(WC_VEHICLE_DEPOT, v->tile);
00669     if (IsLocalCompany()) {
00670       InvalidateAutoreplaceWindow(v->engine_type, v->group_id); // updates the replace Train window
00671     }
00672     GetCompany(_current_company)->num_engines[engine]++;
00673   }
00674 
00675   return value;
00676 }
00677 
00679 static void NormalizeTrainVehInDepot(const Vehicle *u)
00680 {
00681   const Vehicle *v;
00682 
00683   FOR_ALL_VEHICLES(v) {
00684     if (v->type == VEH_TRAIN && IsFreeWagon(v) &&
00685         v->tile == u->tile &&
00686         v->u.rail.track == TRACK_BIT_DEPOT) {
00687       if (CmdFailed(DoCommand(0, v->index | (u->index << 16), 1, DC_EXEC,
00688           CMD_MOVE_RAIL_VEHICLE)))
00689         break;
00690     }
00691   }
00692 }
00693 
00694 static void AddRearEngineToMultiheadedTrain(Vehicle *v, Vehicle *u, bool building)
00695 {
00696   u = new (u) Train();
00697   u->direction = v->direction;
00698   u->owner = v->owner;
00699   u->tile = v->tile;
00700   u->x_pos = v->x_pos;
00701   u->y_pos = v->y_pos;
00702   u->z_pos = v->z_pos;
00703   u->u.rail.track = TRACK_BIT_DEPOT;
00704   u->vehstatus = v->vehstatus & ~VS_STOPPED;
00705 //  u->subtype = 0;
00706   SetMultiheaded(u);
00707   u->spritenum = v->spritenum + 1;
00708   u->cargo_type = v->cargo_type;
00709   u->cargo_subtype = v->cargo_subtype;
00710   u->cargo_cap = v->cargo_cap;
00711   u->u.rail.railtype = v->u.rail.railtype;
00712   if (building) v->SetNext(u);
00713   u->engine_type = v->engine_type;
00714   u->build_year = v->build_year;
00715   if (building) v->value >>= 1;
00716   u->value = v->value;
00717   u->cur_image = 0xAC2;
00718   u->random_bits = VehicleRandomBits();
00719   VehiclePositionChanged(u);
00720 }
00721 
00728 CommandCost CmdBuildRailVehicle(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
00729 {
00730   /* Check if the engine-type is valid (for the company) */
00731   if (!IsEngineBuildable(p1, VEH_TRAIN, _current_company)) return_cmd_error(STR_RAIL_VEHICLE_NOT_AVAILABLE);
00732 
00733   const Engine *e = GetEngine(p1);
00734   CommandCost value(EXPENSES_NEW_VEHICLES, e->GetCost());
00735 
00736   if (flags & DC_QUERY_COST) return value;
00737 
00738   /* Check if the train is actually being built in a depot belonging
00739    * to the company. Doesn't matter if only the cost is queried */
00740   if (!IsRailDepotTile(tile)) return CMD_ERROR;
00741   if (!IsTileOwner(tile, _current_company)) return CMD_ERROR;
00742 
00743   const RailVehicleInfo *rvi = RailVehInfo(p1);
00744   if (rvi->railveh_type == RAILVEH_WAGON) return CmdBuildRailWagon(p1, tile, flags);
00745 
00746   uint num_vehicles =
00747     (rvi->railveh_type == RAILVEH_MULTIHEAD ? 2 : 1) +
00748     CountArticulatedParts(p1, false);
00749 
00750   /* Check if depot and new engine uses the same kind of tracks *
00751    * We need to see if the engine got power on the tile to avoid eletric engines in non-electric depots */
00752   if (!HasPowerOnRail(rvi->railtype, GetRailType(tile))) return CMD_ERROR;
00753 
00754   /* Allow for the dual-heads and the articulated parts, plus one to "terminate" the list. */
00755   Vehicle **vl = AllocaM(Vehicle*, num_vehicles + 1);
00756   memset(vl, 0, sizeof(*vl) * (num_vehicles + 1));
00757 
00758   if (!Vehicle::AllocateList(vl, num_vehicles)) {
00759     return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);
00760   }
00761 
00762   Vehicle *v = vl[0];
00763 
00764   UnitID unit_num = (flags & DC_AUTOREPLACE) ? 0 : GetFreeUnitNumber(VEH_TRAIN);
00765   if (unit_num > _settings_game.vehicle.max_trains) {
00766     return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);
00767   }
00768 
00769   if (flags & DC_EXEC) {
00770     DiagDirection dir = GetRailDepotDirection(tile);
00771     int x = TileX(tile) * TILE_SIZE + _vehicle_initial_x_fract[dir];
00772     int y = TileY(tile) * TILE_SIZE + _vehicle_initial_y_fract[dir];
00773 
00774     v = new (v) Train();
00775     v->unitnumber = unit_num;
00776     v->direction = DiagDirToDir(dir);
00777     v->tile = tile;
00778     v->owner = _current_company;
00779     v->x_pos = x;
00780     v->y_pos = y;
00781     v->z_pos = GetSlopeZ(x, y);
00782 //    v->running_ticks = 0;
00783     v->u.rail.track = TRACK_BIT_DEPOT;
00784     v->vehstatus = VS_HIDDEN | VS_STOPPED | VS_DEFPAL;
00785     v->spritenum = rvi->image_index;
00786     v->cargo_type = rvi->cargo_type;
00787 //    v->cargo_subtype = 0;
00788     v->cargo_cap = rvi->capacity;
00789     v->max_speed = rvi->max_speed;
00790     v->value = value.GetCost();
00791     v->last_station_visited = INVALID_STATION;
00792 //    v->dest_tile = 0;
00793 
00794     v->engine_type = p1;
00795 
00796     v->reliability = e->reliability;
00797     v->reliability_spd_dec = e->reliability_spd_dec;
00798     v->max_age = e->lifelength * DAYS_IN_LEAP_YEAR;
00799 
00800     v->name = NULL;
00801     v->u.rail.railtype = rvi->railtype;
00802     _new_vehicle_id = v->index;
00803 
00804     v->service_interval = _settings_game.vehicle.servint_trains;
00805     v->date_of_last_service = _date;
00806     v->build_year = _cur_year;
00807     v->cur_image = 0xAC2;
00808     v->random_bits = VehicleRandomBits();
00809 
00810 //    v->vehicle_flags = 0;
00811     if (e->flags & ENGINE_EXCLUSIVE_PREVIEW) SetBit(v->vehicle_flags, VF_BUILT_AS_PROTOTYPE);
00812 
00813     v->group_id = DEFAULT_GROUP;
00814 
00815 //    v->subtype = 0;
00816     SetFrontEngine(v);
00817     SetTrainEngine(v);
00818 
00819     VehiclePositionChanged(v);
00820 
00821     if (rvi->railveh_type == RAILVEH_MULTIHEAD) {
00822       SetMultiheaded(v);
00823       AddRearEngineToMultiheadedTrain(vl[0], vl[1], true);
00824       /* Now we need to link the front and rear engines together
00825        * other_multiheaded_part is the pointer that links to the other half of the engine
00826        * vl[0] is the front and vl[1] is the rear
00827        */
00828       vl[0]->u.rail.other_multiheaded_part = vl[1];
00829       vl[1]->u.rail.other_multiheaded_part = vl[0];
00830     } else {
00831       AddArticulatedParts(vl, VEH_TRAIN);
00832     }
00833 
00834     TrainConsistChanged(v, false);
00835     UpdateTrainGroupID(v);
00836 
00837     if (!HasBit(p2, 1) && !(flags & DC_AUTOREPLACE)) { // check if the cars should be added to the new vehicle
00838       NormalizeTrainVehInDepot(v);
00839     }
00840 
00841     InvalidateWindowData(WC_VEHICLE_DEPOT, v->tile);
00842     InvalidateWindowClassesData(WC_TRAINS_LIST, 0);
00843     InvalidateWindow(WC_COMPANY, v->owner);
00844     if (IsLocalCompany()) {
00845       InvalidateAutoreplaceWindow(v->engine_type, v->group_id); // updates the replace Train window
00846     }
00847 
00848     GetCompany(_current_company)->num_engines[p1]++;
00849   }
00850 
00851   return value;
00852 }
00853 
00854 
00855 /* Check if all the wagons of the given train are in a depot, returns the
00856  * number of cars (including loco) then. If not it returns -1 */
00857 int CheckTrainInDepot(const Vehicle *v, bool needs_to_be_stopped)
00858 {
00859   TileIndex tile = v->tile;
00860 
00861   /* check if stopped in a depot */
00862   if (!IsRailDepotTile(tile) || v->cur_speed != 0) return -1;
00863 
00864   int count = 0;
00865   for (; v != NULL; v = v->Next()) {
00866     /* This count is used by the depot code to determine the number of engines
00867      * in the consist. Exclude articulated parts so that autoreplacing to
00868      * engines with more articulated parts than before works correctly.
00869      *
00870      * Also skip counting rear ends of multiheaded engines */
00871     if (!IsArticulatedPart(v) && !IsRearDualheaded(v)) count++;
00872     if (v->u.rail.track != TRACK_BIT_DEPOT || v->tile != tile ||
00873         (IsFrontEngine(v) && needs_to_be_stopped && !(v->vehstatus & VS_STOPPED))) {
00874       return -1;
00875     }
00876   }
00877 
00878   return count;
00879 }
00880 
00881 /* Used to check if the train is inside the depot and verifying that the VS_STOPPED flag is set */
00882 int CheckTrainStoppedInDepot(const Vehicle *v)
00883 {
00884   return CheckTrainInDepot(v, true);
00885 }
00886 
00887 /* Used to check if the train is inside the depot, but not checking the VS_STOPPED flag */
00888 inline bool CheckTrainIsInsideDepot(const Vehicle *v)
00889 {
00890   return CheckTrainInDepot(v, false) > 0;
00891 }
00892 
00899 static Vehicle *UnlinkWagon(Vehicle *v, Vehicle *first)
00900 {
00901   /* unlinking the first vehicle of the chain? */
00902   if (v == first) {
00903     v = GetNextVehicle(v);
00904     if (v == NULL) return NULL;
00905 
00906     if (IsTrainWagon(v)) SetFreeWagon(v);
00907 
00908     /* First can be an articulated engine, meaning GetNextVehicle() isn't
00909      * v->Next(). Thus set the next vehicle of the last articulated part
00910      * and the last articulated part is just before the next vehicle (v). */
00911     v->Previous()->SetNext(NULL);
00912 
00913     return v;
00914   }
00915 
00916   Vehicle *u;
00917   for (u = first; GetNextVehicle(u) != v; u = GetNextVehicle(u)) {}
00918   GetLastEnginePart(u)->SetNext(GetNextVehicle(v));
00919   return first;
00920 }
00921 
00922 static Vehicle *FindGoodVehiclePos(const Vehicle *src)
00923 {
00924   Vehicle *dst;
00925   EngineID eng = src->engine_type;
00926   TileIndex tile = src->tile;
00927 
00928   FOR_ALL_VEHICLES(dst) {
00929     if (dst->type == VEH_TRAIN && IsFreeWagon(dst) && dst->tile == tile && !HASBITS(dst->vehstatus, VS_CRASHED)) {
00930       /* check so all vehicles in the line have the same engine. */
00931       Vehicle *v = dst;
00932 
00933       while (v->engine_type == eng) {
00934         v = v->Next();
00935         if (v == NULL) return dst;
00936       }
00937     }
00938   }
00939 
00940   return NULL;
00941 }
00942 
00943 /*
00944  * add a vehicle v behind vehicle dest
00945  * use this function since it sets flags as needed
00946  */
00947 static void AddWagonToConsist(Vehicle *v, Vehicle *dest)
00948 {
00949   UnlinkWagon(v, v->First());
00950   if (dest == NULL) return;
00951 
00952   Vehicle *next = dest->Next();
00953   v->SetNext(NULL);
00954   dest->SetNext(v);
00955   v->SetNext(next);
00956   ClearFreeWagon(v);
00957   ClearFrontEngine(v);
00958 }
00959 
00960 /*
00961  * move around on the train so rear engines are placed correctly according to the other engines
00962  * always call with the front engine
00963  */
00964 static void NormaliseTrainConsist(Vehicle *v)
00965 {
00966   if (IsFreeWagon(v)) return;
00967 
00968   assert(IsFrontEngine(v));
00969 
00970   for (; v != NULL; v = GetNextVehicle(v)) {
00971     if (!IsMultiheaded(v) || !IsTrainEngine(v)) continue;
00972 
00973     /* make sure that there are no free cars before next engine */
00974     Vehicle *u;
00975     for (u = v; u->Next() != NULL && !IsTrainEngine(u->Next()); u = u->Next()) {}
00976 
00977     if (u == v->u.rail.other_multiheaded_part) continue;
00978     AddWagonToConsist(v->u.rail.other_multiheaded_part, u);
00979   }
00980 }
00981 
00991 CommandCost CmdMoveRailVehicle(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
00992 {
00993   VehicleID s = GB(p1, 0, 16);
00994   VehicleID d = GB(p1, 16, 16);
00995 
00996   if (!IsValidVehicleID(s)) return CMD_ERROR;
00997 
00998   Vehicle *src = GetVehicle(s);
00999 
01000   if (src->type != VEH_TRAIN || !CheckOwnership(src->owner)) return CMD_ERROR;
01001 
01002   /* Do not allow moving crashed vehicles inside the depot, it is likely to cause asserts later */
01003   if (HASBITS(src->vehstatus, VS_CRASHED)) return CMD_ERROR;
01004 
01005   /* if nothing is selected as destination, try and find a matching vehicle to drag to. */
01006   Vehicle *dst;
01007   if (d == INVALID_VEHICLE) {
01008     dst = IsTrainEngine(src) ? NULL : FindGoodVehiclePos(src);
01009   } else {
01010     if (!IsValidVehicleID(d)) return CMD_ERROR;
01011     dst = GetVehicle(d);
01012     if (dst->type != VEH_TRAIN || !CheckOwnership(dst->owner)) return CMD_ERROR;
01013 
01014     /* Do not allow appending to crashed vehicles, too */
01015     if (HASBITS(dst->vehstatus, VS_CRASHED)) return CMD_ERROR;
01016   }
01017 
01018   /* if an articulated part is being handled, deal with its parent vehicle */
01019   while (IsArticulatedPart(src)) src = src->Previous();
01020   if (dst != NULL) {
01021     while (IsArticulatedPart(dst)) dst = dst->Previous();
01022   }
01023 
01024   /* don't move the same vehicle.. */
01025   if (src == dst) return CommandCost();
01026 
01027   /* locate the head of the two chains */
01028   Vehicle *src_head = src->First();
01029   Vehicle *dst_head;
01030   if (dst != NULL) {
01031     dst_head = dst->First();
01032     if (dst_head->tile != src_head->tile) return CMD_ERROR;
01033     /* Now deal with articulated part of destination wagon */
01034     dst = GetLastEnginePart(dst);
01035   } else {
01036     dst_head = NULL;
01037   }
01038 
01039   if (IsRearDualheaded(src)) return_cmd_error(STR_REAR_ENGINE_FOLLOW_FRONT_ERROR);
01040 
01041   /* when moving all wagons, we can't have the same src_head and dst_head */
01042   if (HasBit(p2, 0) && src_head == dst_head) return CommandCost();
01043 
01044   /* check if all vehicles in the source train are stopped inside a depot. */
01045   int src_len = CheckTrainStoppedInDepot(src_head);
01046   if (src_len < 0) return_cmd_error(STR_881A_TRAINS_CAN_ONLY_BE_ALTERED);
01047 
01048   if ((flags & DC_AUTOREPLACE) == 0) {
01049     /* Check whether there are more than 'max_len' train units (articulated parts and rear heads do not count) in the new chain */
01050     int max_len = _settings_game.vehicle.mammoth_trains ? 100 : 10;
01051 
01052     /* check the destination row if the source and destination aren't the same. */
01053     if (src_head != dst_head) {
01054       int dst_len = 0;
01055 
01056       if (dst_head != NULL) {
01057         /* check if all vehicles in the dest train are stopped. */
01058         dst_len = CheckTrainStoppedInDepot(dst_head);
01059         if (dst_len < 0) return_cmd_error(STR_881A_TRAINS_CAN_ONLY_BE_ALTERED);
01060       }
01061 
01062       /* We are moving between rows, so only count the wagons from the source
01063        * row that are being moved. */
01064       if (HasBit(p2, 0)) {
01065         const Vehicle *u;
01066         for (u = src_head; u != src && u != NULL; u = GetNextVehicle(u))
01067           src_len--;
01068       } else {
01069         /* If moving only one vehicle, just count that. */
01070         src_len = 1;
01071       }
01072 
01073       if (src_len + dst_len > max_len) {
01074         /* Abort if we're adding too many wagons to a train. */
01075         if (dst_head != NULL && IsFrontEngine(dst_head)) return_cmd_error(STR_8819_TRAIN_TOO_LONG);
01076         /* Abort if we're making a train on a new row. */
01077         if (dst_head == NULL && IsTrainEngine(src)) return_cmd_error(STR_8819_TRAIN_TOO_LONG);
01078       }
01079     } else {
01080       /* Abort if we're creating a new train on an existing row. */
01081       if (src_len > max_len && src == src_head && IsTrainEngine(GetNextVehicle(src_head)))
01082         return_cmd_error(STR_8819_TRAIN_TOO_LONG);
01083     }
01084   }
01085 
01086   /* moving a loco to a new line?, then we need to assign a unitnumber. */
01087   if (dst == NULL && !IsFrontEngine(src) && IsTrainEngine(src)) {
01088     UnitID unit_num = ((flags & DC_AUTOREPLACE) != 0 ? 0 : GetFreeUnitNumber(VEH_TRAIN));
01089     if (unit_num > _settings_game.vehicle.max_trains)
01090       return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);
01091 
01092     if (flags & DC_EXEC) src->unitnumber = unit_num;
01093   }
01094 
01095   /* When we move the front vehicle, the second vehicle might need a unitnumber */
01096   if (!HasBit(p2, 0) && (IsFreeWagon(src) || (IsFrontEngine(src) && dst == NULL)) && (flags & DC_AUTOREPLACE) == 0) {
01097     Vehicle *second = GetNextUnit(src);
01098     if (second != NULL && IsTrainEngine(second) && GetFreeUnitNumber(VEH_TRAIN) > _settings_game.vehicle.max_trains) {
01099       return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);
01100     }
01101   }
01102 
01103   /*
01104    * Check whether the vehicles in the source chain are in the destination
01105    * chain. This can easily be done by checking whether the first vehicle
01106    * of the source chain is in the destination chain as the Next/Previous
01107    * pointers always make a doubly linked list of it where the assumption
01108    * v->Next()->Previous() == v holds (assuming v->Next() != NULL).
01109    */
01110   bool src_in_dst = false;
01111   for (Vehicle *v = dst_head; !src_in_dst && v != NULL; v = v->Next()) src_in_dst = v == src;
01112 
01113   /*
01114    * If the source chain is in the destination chain then the user is
01115    * only reordering the vehicles, thus not attaching a new vehicle.
01116    * Therefor the 'allow wagon attach' callback does not need to be
01117    * called. If it would be called strange things would happen because
01118    * one 'attaches' an already 'attached' vehicle causing more trouble
01119    * than it actually solves (infinite loops and such).
01120    */
01121   if (dst_head != NULL && !src_in_dst && (flags & DC_AUTOREPLACE) == 0) {
01122     /*
01123      * When performing the 'allow wagon attach' callback, we have to check
01124      * that for each and every wagon, not only the first one. This means
01125      * that we have to test one wagon, attach it to the train and then test
01126      * the next wagon till we have reached the end. We have to restore it
01127      * to the state it was before we 'tried' attaching the train when the
01128      * attaching fails or succeeds because we are not 'only' doing this
01129      * in the DC_EXEC state.
01130      */
01131     Vehicle *dst_tail = dst_head;
01132     while (dst_tail->Next() != NULL) dst_tail = dst_tail->Next();
01133 
01134     Vehicle *orig_tail = dst_tail;
01135     Vehicle *next_to_attach = src;
01136     Vehicle *src_previous = src->Previous();
01137 
01138     while (next_to_attach != NULL) {
01139       /* Don't check callback for articulated or rear dual headed parts */
01140       if (!IsArticulatedPart(next_to_attach) && !IsRearDualheaded(next_to_attach)) {
01141         /* Back up and clear the first_engine data to avoid using wagon override group */
01142         EngineID first_engine = next_to_attach->u.rail.first_engine;
01143         next_to_attach->u.rail.first_engine = INVALID_ENGINE;
01144 
01145         uint16 callback = GetVehicleCallbackParent(CBID_TRAIN_ALLOW_WAGON_ATTACH, 0, 0, dst_head->engine_type, next_to_attach, dst_head);
01146 
01147         /* Restore original first_engine data */
01148         next_to_attach->u.rail.first_engine = first_engine;
01149 
01150         if (callback != CALLBACK_FAILED) {
01151           StringID error = STR_NULL;
01152 
01153           if (callback == 0xFD) error = STR_INCOMPATIBLE_RAIL_TYPES;
01154           if (callback < 0xFD) error = GetGRFStringID(GetEngineGRFID(dst_head->engine_type), 0xD000 + callback);
01155 
01156           if (error != STR_NULL) {
01157             /*
01158              * The attaching is not allowed. In this case 'next_to_attach'
01159              * can contain some vehicles of the 'source' and the destination
01160              * train can have some too. We 'just' add the to-be added wagons
01161              * to the chain and then split it where it was previously
01162              * separated, i.e. the tail of the original destination train.
01163              * Furthermore the 'previous' link of the original source vehicle needs
01164              * to be restored, otherwise the train goes missing in the depot.
01165              */
01166             dst_tail->SetNext(next_to_attach);
01167             orig_tail->SetNext(NULL);
01168             if (src_previous != NULL) src_previous->SetNext(src);
01169 
01170             return_cmd_error(error);
01171           }
01172         }
01173       }
01174 
01175       /* Only check further wagons if told to move the chain */
01176       if (!HasBit(p2, 0)) break;
01177 
01178       /*
01179        * Adding a next wagon to the chain so we can test the other wagons.
01180        * First 'take' the first wagon from 'next_to_attach' and move it
01181        * to the next wagon. Then add that to the tail of the destination
01182        * train and update the tail with the new vehicle.
01183        */
01184       Vehicle *to_add = next_to_attach;
01185       next_to_attach = next_to_attach->Next();
01186 
01187       to_add->SetNext(NULL);
01188       dst_tail->SetNext(to_add);
01189       dst_tail = dst_tail->Next();
01190     }
01191 
01192     /*
01193      * When we reach this the attaching is allowed. It also means that the
01194      * chain of vehicles to attach is empty, so we do not need to merge that.
01195      * This means only the splitting needs to be done.
01196      * Furthermore the 'previous' link of the original source vehicle needs
01197      * to be restored, otherwise the train goes missing in the depot.
01198      */
01199     orig_tail->SetNext(NULL);
01200     if (src_previous != NULL) src_previous->SetNext(src);
01201   }
01202 
01203   /* do it? */
01204   if (flags & DC_EXEC) {
01205     /* If we move the front Engine and if the second vehicle is not an engine
01206        add the whole vehicle to the DEFAULT_GROUP */
01207     if (IsFrontEngine(src) && !IsDefaultGroupID(src->group_id)) {
01208       Vehicle *v = GetNextVehicle(src);
01209 
01210       if (v != NULL && IsTrainEngine(v)) {
01211         v->group_id   = src->group_id;
01212         src->group_id = DEFAULT_GROUP;
01213       }
01214     }
01215 
01216     if (HasBit(p2, 0)) {
01217       /* unlink ALL wagons */
01218       if (src != src_head) {
01219         Vehicle *v = src_head;
01220         while (GetNextVehicle(v) != src) v = GetNextVehicle(v);
01221         GetLastEnginePart(v)->SetNext(NULL);
01222       } else {
01223         InvalidateWindowData(WC_VEHICLE_DEPOT, src_head->tile); // We removed a line
01224         src_head = NULL;
01225       }
01226     } else {
01227       /* if moving within the same chain, dont use dst_head as it may get invalidated */
01228       if (src_head == dst_head) dst_head = NULL;
01229       /* unlink single wagon from linked list */
01230       src_head = UnlinkWagon(src, src_head);
01231       GetLastEnginePart(src)->SetNext(NULL);
01232     }
01233 
01234     if (dst == NULL) {
01235       /* We make a new line in the depot, so we know already that we invalidate the window data */
01236       InvalidateWindowData(WC_VEHICLE_DEPOT, src->tile);
01237 
01238       /* move the train to an empty line. for locomotives, we set the type to TS_Front. for wagons, 4. */
01239       if (IsTrainEngine(src)) {
01240         if (!IsFrontEngine(src)) {
01241           /* setting the type to 0 also involves setting up the orders field. */
01242           SetFrontEngine(src);
01243           assert(src->orders.list == NULL);
01244 
01245           /* Decrease the engines number of the src engine_type */
01246           if (!IsDefaultGroupID(src->group_id) && IsValidGroupID(src->group_id)) {
01247             GetGroup(src->group_id)->num_engines[src->engine_type]--;
01248           }
01249 
01250           /* If we move an engine to a new line affect it to the DEFAULT_GROUP */
01251           src->group_id = DEFAULT_GROUP;
01252         }
01253       } else {
01254         SetFreeWagon(src);
01255       }
01256       dst_head = src;
01257     } else {
01258       if (IsFrontEngine(src)) {
01259         /* the vehicle was previously a loco. need to free the order list and delete vehicle windows etc. */
01260         DeleteWindowById(WC_VEHICLE_VIEW, src->index);
01261         DeleteWindowById(WC_VEHICLE_ORDERS, src->index);
01262         DeleteWindowById(WC_VEHICLE_REFIT, src->index);
01263         DeleteWindowById(WC_VEHICLE_DETAILS, src->index);
01264         DeleteWindowById(WC_VEHICLE_TIMETABLE, src->index);
01265         DeleteVehicleOrders(src);
01266         RemoveVehicleFromGroup(src);
01267       }
01268 
01269       if (IsFrontEngine(src) || IsFreeWagon(src)) {
01270         InvalidateWindowData(WC_VEHICLE_DEPOT, src->tile);
01271         ClearFrontEngine(src);
01272         ClearFreeWagon(src);
01273         src->unitnumber = 0; // doesn't occupy a unitnumber anymore.
01274       }
01275 
01276       /* link in the wagon(s) in the chain. */
01277       {
01278         Vehicle *v;
01279 
01280         for (v = src; GetNextVehicle(v) != NULL; v = GetNextVehicle(v)) {}
01281         GetLastEnginePart(v)->SetNext(dst->Next());
01282       }
01283       dst->SetNext(src);
01284     }
01285 
01286     if (src->u.rail.other_multiheaded_part != NULL) {
01287       if (src->u.rail.other_multiheaded_part == src_head) {
01288         src_head = src_head->Next();
01289       }
01290       AddWagonToConsist(src->u.rail.other_multiheaded_part, src);
01291     }
01292 
01293     /* If there is an engine behind first_engine we moved away, it should become new first_engine
01294      * To do this, CmdMoveRailVehicle must be called once more
01295      * we can't loop forever here because next time we reach this line we will have a front engine */
01296     if (src_head != NULL && !IsFrontEngine(src_head) && IsTrainEngine(src_head)) {
01297       /* As in CmdMoveRailVehicle src_head->group_id will be equal to DEFAULT_GROUP
01298        * we need to save the group and reaffect it to src_head */
01299       const GroupID tmp_g = src_head->group_id;
01300       CmdMoveRailVehicle(0, flags, src_head->index | (INVALID_VEHICLE << 16), 1, text);
01301       SetTrainGroupID(src_head, tmp_g);
01302       src_head = NULL; // don't do anything more to this train since the new call will do it
01303     }
01304 
01305     if (src_head != NULL) {
01306       NormaliseTrainConsist(src_head);
01307       TrainConsistChanged(src_head, false);
01308       UpdateTrainGroupID(src_head);
01309       if (IsFrontEngine(src_head)) {
01310         /* Update the refit button and window */
01311         InvalidateWindow(WC_VEHICLE_REFIT, src_head->index);
01312         InvalidateWindowWidget(WC_VEHICLE_VIEW, src_head->index, VVW_WIDGET_REFIT_VEH);
01313       }
01314       /* Update the depot window */
01315       InvalidateWindow(WC_VEHICLE_DEPOT, src_head->tile);
01316     }
01317 
01318     if (dst_head != NULL) {
01319       NormaliseTrainConsist(dst_head);
01320       TrainConsistChanged(dst_head, false);
01321       UpdateTrainGroupID(dst_head);
01322       if (IsFrontEngine(dst_head)) {
01323         /* Update the refit button and window */
01324         InvalidateWindowWidget(WC_VEHICLE_VIEW, dst_head->index, VVW_WIDGET_REFIT_VEH);
01325         InvalidateWindow(WC_VEHICLE_REFIT, dst_head->index);
01326       }
01327       /* Update the depot window */
01328       InvalidateWindow(WC_VEHICLE_DEPOT, dst_head->tile);
01329     }
01330 
01331     InvalidateWindowClassesData(WC_TRAINS_LIST, 0);
01332   }
01333 
01334   return CommandCost();
01335 }
01336 
01346 CommandCost CmdSellRailWagon(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
01347 {
01348   /* Check if we deleted a vehicle window */
01349   Window *w = NULL;
01350 
01351   if (!IsValidVehicleID(p1) || p2 > 1) return CMD_ERROR;
01352 
01353   Vehicle *v = GetVehicle(p1);
01354 
01355   if (v->type != VEH_TRAIN || !CheckOwnership(v->owner)) return CMD_ERROR;
01356 
01357   if (HASBITS(v->vehstatus, VS_CRASHED)) return_cmd_error(STR_CAN_T_SELL_DESTROYED_VEHICLE);
01358 
01359   while (IsArticulatedPart(v)) v = v->Previous();
01360   Vehicle *first = v->First();
01361 
01362   /* make sure the vehicle is stopped in the depot */
01363   if (CheckTrainStoppedInDepot(first) < 0) {
01364     return_cmd_error(STR_881A_TRAINS_CAN_ONLY_BE_ALTERED);
01365   }
01366 
01367   if (IsRearDualheaded(v)) return_cmd_error(STR_REAR_ENGINE_FOLLOW_FRONT_ERROR);
01368 
01369   if (flags & DC_EXEC) {
01370     if (v == first && IsFrontEngine(first)) {
01371       DeleteWindowById(WC_VEHICLE_VIEW, first->index);
01372       DeleteWindowById(WC_VEHICLE_ORDERS, first->index);
01373       DeleteWindowById(WC_VEHICLE_REFIT, first->index);
01374       DeleteWindowById(WC_VEHICLE_DETAILS, first->index);
01375       DeleteWindowById(WC_VEHICLE_TIMETABLE, first->index);
01376     }
01377     InvalidateWindow(WC_VEHICLE_DEPOT, first->tile);
01378     InvalidateWindowClassesData(WC_TRAINS_LIST, 0);
01379   }
01380 
01381   CommandCost cost(EXPENSES_NEW_VEHICLES);
01382   switch (p2) {
01383     case 0: { /* Delete given wagon */
01384       bool switch_engine = false;    // update second wagon to engine?
01385 
01386       /* 1. Delete the engine, if it is dualheaded also delete the matching
01387        * rear engine of the loco (from the point of deletion onwards) */
01388       Vehicle *rear = (IsMultiheaded(v) &&
01389         IsTrainEngine(v)) ? v->u.rail.other_multiheaded_part : NULL;
01390 
01391       if (rear != NULL) {
01392         cost.AddCost(-rear->value);
01393         if (flags & DC_EXEC) {
01394           UnlinkWagon(rear, first);
01395           delete rear;
01396         }
01397       }
01398 
01399       /* 2. We are selling the front vehicle, some special action might be required
01400        * here, so take attention */
01401       if (v == first) {
01402         Vehicle *new_f = GetNextVehicle(first);
01403 
01404         /* 2.2 If there are wagons present after the deleted front engine, check
01405          * if the second wagon (which will be first) is an engine. If it is one,
01406          * promote it as a new train, retaining the unitnumber, orders */
01407         if (new_f != NULL && IsTrainEngine(new_f)) {
01408           if (IsTrainEngine(first)) {
01409             /* Let the new front engine take over the setup of the old engine */
01410             switch_engine = true;
01411 
01412             if (flags & DC_EXEC) {
01413               /* Make sure the group counts stay correct. */
01414               new_f->group_id        = first->group_id;
01415               first->group_id        = DEFAULT_GROUP;
01416 
01417               /* Copy orders (by sharing) */
01418               new_f->orders.list     = first->orders.list;
01419               new_f->AddToShared(first);
01420               DeleteVehicleOrders(first);
01421 
01422               /* Copy other important data from the front engine */
01423               new_f->CopyVehicleConfigAndStatistics(first);
01424 
01425               /* If we deleted a window then open a new one for the 'new' train */
01426               if (IsLocalCompany() && w != NULL) ShowVehicleViewWindow(new_f);
01427             }
01428           } else {
01429             /* We are selling a free wagon, and construct a new train at the same time.
01430              * This needs lots of extra checks (e.g. train limit), which are done by first moving
01431              * the remaining vehicles to a new row */
01432             cost.AddCost(DoCommand(0, new_f->index | INVALID_VEHICLE << 16, 1, flags, CMD_MOVE_RAIL_VEHICLE));
01433             if (cost.Failed()) return cost;
01434           }
01435         }
01436       }
01437 
01438       /* 3. Delete the requested wagon */
01439       cost.AddCost(-v->value);
01440       if (flags & DC_EXEC) {
01441         first = UnlinkWagon(v, first);
01442         delete v;
01443 
01444         /* 4 If the second wagon was an engine, update it to front_engine
01445          * which UnlinkWagon() has changed to TS_Free_Car */
01446         if (switch_engine) SetFrontEngine(first);
01447 
01448         /* 5. If the train still exists, update its acceleration, window, etc. */
01449         if (first != NULL) {
01450           NormaliseTrainConsist(first);
01451           TrainConsistChanged(first, false);
01452           UpdateTrainGroupID(first);
01453           if (IsFrontEngine(first)) InvalidateWindow(WC_VEHICLE_REFIT, first->index);
01454         }
01455 
01456       }
01457     } break;
01458     case 1: { /* Delete wagon and all wagons after it given certain criteria */
01459       /* Start deleting every vehicle after the selected one
01460        * If we encounter a matching rear-engine to a front-engine
01461        * earlier in the chain (before deletion), leave it alone */
01462       for (Vehicle *tmp; v != NULL; v = tmp) {
01463         tmp = GetNextVehicle(v);
01464 
01465         if (IsMultiheaded(v)) {
01466           if (IsTrainEngine(v)) {
01467             /* We got a front engine of a multiheaded set. Now we will sell the rear end too */
01468             Vehicle *rear = v->u.rail.other_multiheaded_part;
01469 
01470             if (rear != NULL) {
01471               cost.AddCost(-rear->value);
01472 
01473               /* If this is a multiheaded vehicle with nothing
01474                * between the parts, tmp will be pointing to the
01475                * rear part, which is unlinked from the train and
01476                * deleted here. However, because tmp has already
01477                * been set it needs to be updated now so that the
01478                * loop never sees the rear part. */
01479               if (tmp == rear) tmp = GetNextVehicle(tmp);
01480 
01481               if (flags & DC_EXEC) {
01482                 first = UnlinkWagon(rear, first);
01483                 delete rear;
01484               }
01485             }
01486           } else if (v->u.rail.other_multiheaded_part != NULL) {
01487             /* The front to this engine is earlier in this train. Do nothing */
01488             continue;
01489           }
01490         }
01491 
01492         cost.AddCost(-v->value);
01493         if (flags & DC_EXEC) {
01494           first = UnlinkWagon(v, first);
01495           delete v;
01496         }
01497       }
01498 
01499       /* 3. If it is still a valid train after selling, update its acceleration and cached values */
01500       if (flags & DC_EXEC && first != NULL) {
01501         NormaliseTrainConsist(first);
01502         TrainConsistChanged(first, false);
01503         UpdateTrainGroupID(first);
01504         InvalidateWindow(WC_VEHICLE_REFIT, first->index);
01505       }
01506     } break;
01507   }
01508   return cost;
01509 }
01510 
01511 void Train::UpdateDeltaXY(Direction direction)
01512 {
01513 #define MKIT(a, b, c, d) ((a & 0xFF) << 24) | ((b & 0xFF) << 16) | ((c & 0xFF) << 8) | ((d & 0xFF) << 0)
01514   static const uint32 _delta_xy_table[8] = {
01515     MKIT(3, 3, -1, -1),
01516     MKIT(3, 7, -1, -3),
01517     MKIT(3, 3, -1, -1),
01518     MKIT(7, 3, -3, -1),
01519     MKIT(3, 3, -1, -1),
01520     MKIT(3, 7, -1, -3),
01521     MKIT(3, 3, -1, -1),
01522     MKIT(7, 3, -3, -1),
01523   };
01524 #undef MKIT
01525 
01526   uint32 x = _delta_xy_table[direction];
01527   this->x_offs        = GB(x,  0, 8);
01528   this->y_offs        = GB(x,  8, 8);
01529   this->x_extent      = GB(x, 16, 8);
01530   this->y_extent      = GB(x, 24, 8);
01531   this->z_extent      = 6;
01532 }
01533 
01534 static void UpdateVarsAfterSwap(Vehicle *v)
01535 {
01536   v->UpdateDeltaXY(v->direction);
01537   v->cur_image = v->GetImage(v->direction);
01538   BeginVehicleMove(v);
01539   VehiclePositionChanged(v);
01540   EndVehicleMove(v);
01541 }
01542 
01543 static inline void SetLastSpeed(Vehicle *v, int spd)
01544 {
01545   int old = v->u.rail.last_speed;
01546   if (spd != old) {
01547     v->u.rail.last_speed = spd;
01548     if (_settings_client.gui.vehicle_speed || (old == 0) != (spd == 0)) {
01549       InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
01550     }
01551   }
01552 }
01553 
01555 static void MarkTrainAsStuck(Vehicle *v)
01556 {
01557   if (!HasBit(v->u.rail.flags, VRF_TRAIN_STUCK)) {
01558     /* It is the first time the problem occured, set the "train stuck" flag. */
01559     SetBit(v->u.rail.flags, VRF_TRAIN_STUCK);
01560     v->load_unload_time_rem = 0;
01561 
01562     /* Stop train */
01563     v->cur_speed = 0;
01564     v->subspeed = 0;
01565     SetLastSpeed(v, 0);
01566 
01567     InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
01568   }
01569 }
01570 
01571 static void SwapTrainFlags(uint16 *swap_flag1, uint16 *swap_flag2)
01572 {
01573   uint16 flag1 = *swap_flag1;
01574   uint16 flag2 = *swap_flag2;
01575 
01576   /* Clear the flags */
01577   ClrBit(*swap_flag1, VRF_GOINGUP);
01578   ClrBit(*swap_flag1, VRF_GOINGDOWN);
01579   ClrBit(*swap_flag2, VRF_GOINGUP);
01580   ClrBit(*swap_flag2, VRF_GOINGDOWN);
01581 
01582   /* Reverse the rail-flags (if needed) */
01583   if (HasBit(flag1, VRF_GOINGUP)) {
01584     SetBit(*swap_flag2, VRF_GOINGDOWN);
01585   } else if (HasBit(flag1, VRF_GOINGDOWN)) {
01586     SetBit(*swap_flag2, VRF_GOINGUP);
01587   }
01588   if (HasBit(flag2, VRF_GOINGUP)) {
01589     SetBit(*swap_flag1, VRF_GOINGDOWN);
01590   } else if (HasBit(flag2, VRF_GOINGDOWN)) {
01591     SetBit(*swap_flag1, VRF_GOINGUP);
01592   }
01593 }
01594 
01595 static void ReverseTrainSwapVeh(Vehicle *v, int l, int r)
01596 {
01597   Vehicle *a, *b;
01598 
01599   /* locate vehicles to swap */
01600   for (a = v; l != 0; l--) a = a->Next();
01601   for (b = v; r != 0; r--) b = b->Next();
01602 
01603   if (a != b) {
01604     /* swap the hidden bits */
01605     {
01606       uint16 tmp = (a->vehstatus & ~VS_HIDDEN) | (b->vehstatus&VS_HIDDEN);
01607       b->vehstatus = (b->vehstatus & ~VS_HIDDEN) | (a->vehstatus&VS_HIDDEN);
01608       a->vehstatus = tmp;
01609     }
01610 
01611     Swap(a->u.rail.track, b->u.rail.track);
01612     Swap(a->direction,    b->direction);
01613 
01614     /* toggle direction */
01615     if (a->u.rail.track != TRACK_BIT_DEPOT) a->direction = ReverseDir(a->direction);
01616     if (b->u.rail.track != TRACK_BIT_DEPOT) b->direction = ReverseDir(b->direction);
01617 
01618     Swap(a->x_pos, b->x_pos);
01619     Swap(a->y_pos, b->y_pos);
01620     Swap(a->tile,  b->tile);
01621     Swap(a->z_pos, b->z_pos);
01622 
01623     SwapTrainFlags(&a->u.rail.flags, &b->u.rail.flags);
01624 
01625     /* update other vars */
01626     UpdateVarsAfterSwap(a);
01627     UpdateVarsAfterSwap(b);
01628 
01629     /* call the proper EnterTile function unless we are in a wormhole */
01630     if (a->u.rail.track != TRACK_BIT_WORMHOLE) VehicleEnterTile(a, a->tile, a->x_pos, a->y_pos);
01631     if (b->u.rail.track != TRACK_BIT_WORMHOLE) VehicleEnterTile(b, b->tile, b->x_pos, b->y_pos);
01632   } else {
01633     if (a->u.rail.track != TRACK_BIT_DEPOT) a->direction = ReverseDir(a->direction);
01634     UpdateVarsAfterSwap(a);
01635 
01636     if (a->u.rail.track != TRACK_BIT_WORMHOLE) VehicleEnterTile(a, a->tile, a->x_pos, a->y_pos);
01637   }
01638 
01639   /* Update train's power incase tiles were different rail type */
01640   TrainPowerChanged(v);
01641 }
01642 
01643 
01649 static Vehicle *TrainOnTileEnum(Vehicle *v, void *)
01650 {
01651   return (v->type == VEH_TRAIN) ? v : NULL;
01652 }
01653 
01654 
01661 static Vehicle *TrainApproachingCrossingEnum(Vehicle *v, void *data)
01662 {
01663   /* not a train || not front engine || crashed */
01664   if (v->type != VEH_TRAIN || !IsFrontEngine(v) || v->vehstatus & VS_CRASHED) return NULL;
01665 
01666   TileIndex tile = *(TileIndex*)data;
01667 
01668   if (TrainApproachingCrossingTile(v) != tile) return NULL;
01669 
01670   return v;
01671 }
01672 
01673 
01680 static bool TrainApproachingCrossing(TileIndex tile)
01681 {
01682   assert(IsLevelCrossingTile(tile));
01683 
01684   DiagDirection dir = AxisToDiagDir(GetCrossingRailAxis(tile));
01685   TileIndex tile_from = tile + TileOffsByDiagDir(dir);
01686 
01687   if (HasVehicleOnPos(tile_from, &tile, &TrainApproachingCrossingEnum)) return true;
01688 
01689   dir = ReverseDiagDir(dir);
01690   tile_from = tile + TileOffsByDiagDir(dir);
01691 
01692   return HasVehicleOnPos(tile_from, &tile, &TrainApproachingCrossingEnum);
01693 }
01694 
01695 
01702 void UpdateLevelCrossing(TileIndex tile, bool sound)
01703 {
01704   assert(IsLevelCrossingTile(tile));
01705 
01706   /* train on crossing || train approaching crossing || reserved */
01707   bool new_state = HasVehicleOnPos(tile, NULL, &TrainOnTileEnum) || TrainApproachingCrossing(tile) || GetCrossingReservation(tile);
01708 
01709   if (new_state != IsCrossingBarred(tile)) {
01710     if (new_state && sound) {
01711       SndPlayTileFx(SND_0E_LEVEL_CROSSING, tile);
01712     }
01713     SetCrossingBarred(tile, new_state);
01714     MarkTileDirtyByTile(tile);
01715   }
01716 }
01717 
01718 
01724 static inline void MaybeBarCrossingWithSound(TileIndex tile)
01725 {
01726   if (!IsCrossingBarred(tile)) {
01727     BarCrossing(tile);
01728     SndPlayTileFx(SND_0E_LEVEL_CROSSING, tile);
01729     MarkTileDirtyByTile(tile);
01730   }
01731 }
01732 
01733 
01739 static void AdvanceWagonsBeforeSwap(Vehicle *v)
01740 {
01741   Vehicle *base = v;
01742   Vehicle *first = base;                    // first vehicle to move
01743   Vehicle *last = GetLastVehicleInChain(v); // last vehicle to move
01744   uint length = CountVehiclesInChain(v);
01745 
01746   while (length > 2) {
01747     last = last->Previous();
01748     first = first->Next();
01749 
01750     int differential = base->u.rail.cached_veh_length - last->u.rail.cached_veh_length;
01751 
01752     /* do not update images now
01753      * negative differential will be handled in AdvanceWagonsAfterSwap() */
01754     for (int i = 0; i < differential; i++) TrainController(first, last->Next(), false);
01755 
01756     base = first; // == base->Next()
01757     length -= 2;
01758   }
01759 }
01760 
01761 
01767 static void AdvanceWagonsAfterSwap(Vehicle *v)
01768 {
01769   /* first of all, fix the situation when the train was entering a depot */
01770   Vehicle *dep = v; // last vehicle in front of just left depot
01771   while (dep->Next() != NULL && (dep->u.rail.track == TRACK_BIT_DEPOT || dep->Next()->u.rail.track != TRACK_BIT_DEPOT)) {
01772     dep = dep->Next(); // find first vehicle outside of a depot, with next vehicle inside a depot
01773   }
01774 
01775   Vehicle *leave = dep->Next(); // first vehicle in a depot we are leaving now
01776 
01777   if (leave != NULL) {
01778     /* 'pull' next wagon out of the depot, so we won't miss it (it could stay in depot forever) */
01779     int d = TicksToLeaveDepot(dep);
01780 
01781     if (d <= 0) {
01782       leave->vehstatus &= ~VS_HIDDEN; // move it out of the depot
01783       leave->u.rail.track = TrackToTrackBits(GetRailDepotTrack(leave->tile));
01784       for (int i = 0; i >= d; i--) TrainController(leave, NULL, false); // maybe move it, and maybe let another wagon leave
01785     }
01786   } else {
01787     dep = NULL; // no vehicle in a depot, so no vehicle leaving a depot
01788   }
01789 
01790   Vehicle *base = v;
01791   Vehicle *first = base;                    // first vehicle to move
01792   Vehicle *last = GetLastVehicleInChain(v); // last vehicle to move
01793   uint length = CountVehiclesInChain(v);
01794 
01795   /* we have to make sure all wagons that leave a depot because of train reversing are moved coorectly
01796    * they have already correct spacing, so we have to make sure they are moved how they should */
01797   bool nomove = (dep == NULL); // if there is no vehicle leaving a depot, limit the number of wagons moved immediatelly
01798 
01799   while (length > 2) {
01800     /* we reached vehicle (originally) in front of a depot, stop now
01801      * (we would move wagons that are alredy moved with new wagon length) */
01802     if (base == dep) break;
01803 
01804     /* the last wagon was that one leaving a depot, so do not move it anymore */
01805     if (last == dep) nomove = true;
01806 
01807     last = last->Previous();
01808     first = first->Next();
01809 
01810     int differential = last->u.rail.cached_veh_length - base->u.rail.cached_veh_length;
01811 
01812     /* do not update images now */
01813     for (int i = 0; i < differential; i++) TrainController(first, (nomove ? last->Next() : NULL), false);
01814 
01815     base = first; // == base->Next()
01816     length -= 2;
01817   }
01818 }
01819 
01820 
01821 static void ReverseTrainDirection(Vehicle *v)
01822 {
01823   if (IsRailDepotTile(v->tile)) {
01824     InvalidateWindowData(WC_VEHICLE_DEPOT, v->tile);
01825   }
01826 
01827   /* Clear path reservation in front. */
01828   FreeTrainTrackReservation(v);
01829 
01830   /* Check if we were approaching a rail/road-crossing */
01831   TileIndex crossing = TrainApproachingCrossingTile(v);
01832 
01833   /* count number of vehicles */
01834   int r = CountVehiclesInChain(v) - 1;  // number of vehicles - 1
01835 
01836   AdvanceWagonsBeforeSwap(v);
01837 
01838   /* swap start<>end, start+1<>end-1, ... */
01839   int l = 0;
01840   do {
01841     ReverseTrainSwapVeh(v, l++, r--);
01842   } while (l <= r);
01843 
01844   AdvanceWagonsAfterSwap(v);
01845 
01846   if (IsRailDepotTile(v->tile)) {
01847     InvalidateWindowData(WC_VEHICLE_DEPOT, v->tile);
01848   }
01849 
01850   ToggleBit(v->u.rail.flags, VRF_TOGGLE_REVERSE);
01851 
01852   ClrBit(v->u.rail.flags, VRF_REVERSING);
01853 
01854   /* recalculate cached data */
01855   TrainConsistChanged(v, true);
01856 
01857   /* update all images */
01858   for (Vehicle *u = v; u != NULL; u = u->Next()) u->cur_image = u->GetImage(u->direction);
01859 
01860   /* update crossing we were approaching */
01861   if (crossing != INVALID_TILE) UpdateLevelCrossing(crossing);
01862 
01863   /* maybe we are approaching crossing now, after reversal */
01864   crossing = TrainApproachingCrossingTile(v);
01865   if (crossing != INVALID_TILE) MaybeBarCrossingWithSound(crossing);
01866 
01867   /* If we are inside a depot after reversing, don't bother with path reserving. */
01868   if (v->u.rail.track & TRACK_BIT_DEPOT) {
01869     /* Can't be stuck here as inside a depot is always a safe tile. */
01870     if (HasBit(v->u.rail.flags, VRF_TRAIN_STUCK)) InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
01871     ClrBit(v->u.rail.flags, VRF_TRAIN_STUCK);
01872     return;
01873   }
01874 
01875   /* TrainExitDir does not always produce the desired dir for depots and
01876    * tunnels/bridges that is needed for UpdateSignalsOnSegment. */
01877   DiagDirection dir = TrainExitDir(v->direction, v->u.rail.track);
01878   if (IsRailDepotTile(v->tile) || IsTileType(v->tile, MP_TUNNELBRIDGE)) dir = INVALID_DIAGDIR;
01879 
01880   if (UpdateSignalsOnSegment(v->tile, dir, v->owner) == SIGSEG_PBS || _settings_game.pf.reserve_paths) {
01881     /* If we are currently on a tile with conventional signals, we can't treat the
01882      * current tile as a safe tile or we would enter a PBS block without a reservation. */
01883     bool first_tile_okay = !(IsTileType(v->tile, MP_RAILWAY) &&
01884       HasSignalOnTrackdir(v->tile, GetVehicleTrackdir(v)) &&
01885       !IsPbsSignal(GetSignalType(v->tile, FindFirstTrack(v->u.rail.track))));
01886 
01887     if (IsRailwayStationTile(v->tile)) SetRailwayStationPlatformReservation(v->tile, TrackdirToExitdir(GetVehicleTrackdir(v)), true);
01888     if (TryPathReserve(v, false, first_tile_okay)) {
01889       /* Do a look-ahead now in case our current tile was already a safe tile. */
01890       CheckNextTrainTile(v);
01891     } else if (v->current_order.GetType() != OT_LOADING) {
01892       /* Do not wait for a way out when we're still loading */
01893       MarkTrainAsStuck(v);
01894     }
01895   } else if (HasBit(v->u.rail.flags, VRF_TRAIN_STUCK)) {
01896     /* A train not inside a PBS block can't be stuck. */
01897     ClrBit(v->u.rail.flags, VRF_TRAIN_STUCK);
01898     v->load_unload_time_rem = 0;
01899   }
01900 }
01901 
01908 CommandCost CmdReverseTrainDirection(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
01909 {
01910   if (!IsValidVehicleID(p1)) return CMD_ERROR;
01911 
01912   Vehicle *v = GetVehicle(p1);
01913 
01914   if (v->type != VEH_TRAIN || !CheckOwnership(v->owner)) return CMD_ERROR;
01915 
01916   if (p2 != 0) {
01917     /* turn a single unit around */
01918 
01919     if (IsMultiheaded(v) || HasBit(EngInfo(v->engine_type)->callbackmask, CBM_VEHICLE_ARTIC_ENGINE)) {
01920       return_cmd_error(STR_ONLY_TURN_SINGLE_UNIT);
01921     }
01922 
01923     Vehicle *front = v->First();
01924     /* make sure the vehicle is stopped in the depot */
01925     if (CheckTrainStoppedInDepot(front) < 0) {
01926       return_cmd_error(STR_881A_TRAINS_CAN_ONLY_BE_ALTERED);
01927     }
01928 
01929     if (flags & DC_EXEC) {
01930       ToggleBit(v->u.rail.flags, VRF_REVERSE_DIRECTION);
01931       InvalidateWindow(WC_VEHICLE_DEPOT, v->tile);
01932       InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
01933     }
01934   } else {
01935     /* turn the whole train around */
01936     if (v->vehstatus & VS_CRASHED || v->breakdown_ctr != 0) return CMD_ERROR;
01937 
01938     if (flags & DC_EXEC) {
01939       /* Properly leave the station if we are loading and won't be loading anymore */
01940       if (v->current_order.IsType(OT_LOADING)) {
01941         const Vehicle *last = v;
01942         while (last->Next() != NULL) last = last->Next();
01943 
01944         /* not a station || different station --> leave the station */
01945         if (!IsTileType(last->tile, MP_STATION) || GetStationIndex(last->tile) != GetStationIndex(v->tile)) {
01946           v->LeaveStation();
01947         }
01948       }
01949 
01950       if (_settings_game.vehicle.train_acceleration_model != TAM_ORIGINAL && v->cur_speed != 0) {
01951         ToggleBit(v->u.rail.flags, VRF_REVERSING);
01952       } else {
01953         v->cur_speed = 0;
01954         SetLastSpeed(v, 0);
01955         HideFillingPercent(&v->fill_percent_te_id);
01956         ReverseTrainDirection(v);
01957       }
01958     }
01959   }
01960   return CommandCost();
01961 }
01962 
01969 CommandCost CmdForceTrainProceed(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
01970 {
01971   if (!IsValidVehicleID(p1)) return CMD_ERROR;
01972 
01973   Vehicle *v = GetVehicle(p1);
01974 
01975   if (v->type != VEH_TRAIN || !CheckOwnership(v->owner)) return CMD_ERROR;
01976 
01977   if (flags & DC_EXEC) v->u.rail.force_proceed = 0x50;
01978 
01979   return CommandCost();
01980 }
01981 
01992 CommandCost CmdRefitRailVehicle(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
01993 {
01994   CargoID new_cid = GB(p2, 0, 8);
01995   byte new_subtype = GB(p2, 8, 8);
01996   bool only_this = HasBit(p2, 16);
01997 
01998   if (!IsValidVehicleID(p1)) return CMD_ERROR;
01999 
02000   Vehicle *v = GetVehicle(p1);
02001 
02002   if (v->type != VEH_TRAIN || !CheckOwnership(v->owner)) return CMD_ERROR;
02003   if (CheckTrainStoppedInDepot(v) < 0) return_cmd_error(STR_TRAIN_MUST_BE_STOPPED);
02004   if (v->vehstatus & VS_CRASHED) return_cmd_error(STR_CAN_T_REFIT_DESTROYED_VEHICLE);
02005 
02006   /* Check cargo */
02007   if (new_cid >= NUM_CARGO) return CMD_ERROR;
02008 
02009   CommandCost cost(EXPENSES_TRAIN_RUN);
02010   uint num = 0;
02011 
02012   do {
02013     /* XXX: We also refit all the attached wagons en-masse if they
02014      * can be refitted. This is how TTDPatch does it.  TODO: Have
02015      * some nice [Refit] button near each wagon. --pasky */
02016     if (!CanRefitTo(v->engine_type, new_cid)) continue;
02017 
02018     if (v->cargo_cap != 0) {
02019       uint16 amount = CALLBACK_FAILED;
02020 
02021       if (HasBit(EngInfo(v->engine_type)->callbackmask, CBM_VEHICLE_REFIT_CAPACITY)) {
02022         /* Back up the vehicle's cargo type */
02023         CargoID temp_cid = v->cargo_type;
02024         byte temp_subtype = v->cargo_subtype;
02025         v->cargo_type = new_cid;
02026         v->cargo_subtype = new_subtype;
02027         /* Check the refit capacity callback */
02028         amount = GetVehicleCallback(CBID_VEHICLE_REFIT_CAPACITY, 0, 0, v->engine_type, v);
02029         /* Restore the original cargo type */
02030         v->cargo_type = temp_cid;
02031         v->cargo_subtype = temp_subtype;
02032       }
02033 
02034       if (amount == CALLBACK_FAILED) { // callback failed or not used, use default
02035         const RailVehicleInfo *rvi = RailVehInfo(v->engine_type);
02036         CargoID old_cid = rvi->cargo_type;
02037         /* normally, the capacity depends on the cargo type, a rail vehicle can
02038          * carry twice as much mail/goods as normal cargo, and four times as
02039          * many passengers
02040          */
02041         amount = rvi->capacity;
02042         switch (old_cid) {
02043           case CT_PASSENGERS: break;
02044           case CT_MAIL:
02045           case CT_GOODS: amount *= 2; break;
02046           default:       amount *= 4; break;
02047         }
02048         switch (new_cid) {
02049           case CT_PASSENGERS: break;
02050           case CT_MAIL:
02051           case CT_GOODS: amount /= 2; break;
02052           default:       amount /= 4; break;
02053         }
02054       }
02055 
02056       if (new_cid != v->cargo_type) {
02057         cost.AddCost(GetRefitCost(v->engine_type));
02058       }
02059 
02060       num += amount;
02061       if (flags & DC_EXEC) {
02062         v->cargo.Truncate((v->cargo_type == new_cid) ? amount : 0);
02063         v->cargo_type = new_cid;
02064         v->cargo_cap = amount;
02065         v->cargo_subtype = new_subtype;
02066         InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
02067         InvalidateWindow(WC_VEHICLE_DEPOT, v->tile);
02068         InvalidateWindowClassesData(WC_TRAINS_LIST, 0);
02069       }
02070     }
02071   } while ((v = v->Next()) != NULL && !only_this);
02072 
02073   _returned_refit_capacity = num;
02074 
02075   /* Update the train's cached variables */
02076   if (flags & DC_EXEC) TrainConsistChanged(GetVehicle(p1)->First(), false);
02077 
02078   return cost;
02079 }
02080 
02081 struct TrainFindDepotData {
02082   uint best_length;
02083   TileIndex tile;
02084   Owner owner;
02089   bool reverse;
02090 };
02091 
02092 static bool NtpCallbFindDepot(TileIndex tile, TrainFindDepotData *tfdd, int track, uint length)
02093 {
02094   if (IsTileType(tile, MP_RAILWAY) &&
02095       IsTileOwner(tile, tfdd->owner) &&
02096       IsRailDepot(tile)) {
02097     /* approximate number of tiles by dividing by DIAG_FACTOR */
02098     tfdd->best_length = length / DIAG_FACTOR;
02099     tfdd->tile = tile;
02100     return true;
02101   }
02102 
02103   return false;
02104 }
02105 
02108 static TrainFindDepotData FindClosestTrainDepot(Vehicle *v, int max_distance)
02109 {
02110   assert(!(v->vehstatus & VS_CRASHED));
02111 
02112   TrainFindDepotData tfdd;
02113   tfdd.owner = v->owner;
02114   tfdd.reverse = false;
02115 
02116   if (IsRailDepotTile(v->tile)) {
02117     tfdd.tile = v->tile;
02118     tfdd.best_length = 0;
02119     return tfdd;
02120   }
02121 
02122   PBSTileInfo origin = FollowTrainReservation(v);
02123   if (IsRailDepotTile(origin.tile)) {
02124     tfdd.tile = origin.tile;
02125     tfdd.best_length = 0;
02126     return tfdd;
02127   }
02128 
02129   tfdd.best_length = UINT_MAX;
02130 
02131   uint8 pathfinder = _settings_game.pf.pathfinder_for_trains;
02132   if ((_settings_game.pf.reserve_paths || HasReservedTracks(v->tile, v->u.rail.track)) && pathfinder == VPF_NTP) pathfinder = VPF_NPF;
02133 
02134   switch (pathfinder) {
02135     case VPF_YAPF: { /* YAPF */
02136       bool found = YapfFindNearestRailDepotTwoWay(v, max_distance, NPF_INFINITE_PENALTY, &tfdd.tile, &tfdd.reverse);
02137       tfdd.best_length = found ? max_distance / 2 : UINT_MAX; // some fake distance or NOT_FOUND
02138     } break;
02139 
02140     case VPF_NPF: { /* NPF */
02141       const Vehicle *last = GetLastVehicleInChain(v);
02142       Trackdir trackdir = GetVehicleTrackdir(v);
02143       Trackdir trackdir_rev = ReverseTrackdir(GetVehicleTrackdir(last));
02144 
02145       assert(trackdir != INVALID_TRACKDIR);
02146       NPFFoundTargetData ftd = NPFRouteToDepotBreadthFirstTwoWay(v->tile, trackdir, false, last->tile, trackdir_rev, false, TRANSPORT_RAIL, 0, v->owner, v->u.rail.compatible_railtypes, NPF_INFINITE_PENALTY);
02147       if (ftd.best_bird_dist == 0) {
02148         /* Found target */
02149         tfdd.tile = ftd.node.tile;
02150         /* Our caller expects a number of tiles, so we just approximate that
02151          * number by this. It might not be completely what we want, but it will
02152          * work for now :-) We can possibly change this when the old pathfinder
02153          * is removed. */
02154         tfdd.best_length = ftd.best_path_dist / NPF_TILE_LENGTH;
02155         if (NPFGetFlag(&ftd.node, NPF_FLAG_REVERSE)) tfdd.reverse = true;
02156       }
02157     } break;
02158 
02159     default:
02160     case VPF_NTP: { /* NTP */
02161       /* search in the forward direction first. */
02162       DiagDirection i = TrainExitDir(v->direction, v->u.rail.track);
02163       NewTrainPathfind(v->tile, 0, v->u.rail.compatible_railtypes, i, (NTPEnumProc*)NtpCallbFindDepot, &tfdd);
02164       if (tfdd.best_length == UINT_MAX){
02165         tfdd.reverse = true;
02166         /* search in backwards direction */
02167         i = TrainExitDir(ReverseDir(v->direction), v->u.rail.track);
02168         NewTrainPathfind(v->tile, 0, v->u.rail.compatible_railtypes, i, (NTPEnumProc*)NtpCallbFindDepot, &tfdd);
02169       }
02170     } break;
02171   }
02172 
02173   return tfdd;
02174 }
02175 
02176 bool Train::FindClosestDepot(TileIndex *location, DestinationID *destination, bool *reverse)
02177 {
02178   TrainFindDepotData tfdd = FindClosestTrainDepot(this, 0);
02179   if (tfdd.best_length == UINT_MAX) return false;
02180 
02181   if (location    != NULL) *location    = tfdd.tile;
02182   if (destination != NULL) *destination = GetDepotByTile(tfdd.tile)->index;
02183   if (reverse     != NULL) *reverse     = tfdd.reverse;
02184 
02185   return true;
02186 }
02187 
02196 CommandCost CmdSendTrainToDepot(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
02197 {
02198   if (p2 & DEPOT_MASS_SEND) {
02199     /* Mass goto depot requested */
02200     if (!ValidVLWFlags(p2 & VLW_MASK)) return CMD_ERROR;
02201     return SendAllVehiclesToDepot(VEH_TRAIN, flags, p2 & DEPOT_SERVICE, _current_company, (p2 & VLW_MASK), p1);
02202   }
02203 
02204   if (!IsValidVehicleID(p1)) return CMD_ERROR;
02205 
02206   Vehicle *v = GetVehicle(p1);
02207 
02208   if (v->type != VEH_TRAIN) return CMD_ERROR;
02209 
02210   return v->SendToDepot(flags, (DepotCommand)(p2 & DEPOT_COMMAND_MASK));
02211 }
02212 
02213 
02214 void OnTick_Train()
02215 {
02216   _age_cargo_skip_counter = (_age_cargo_skip_counter == 0) ? 184 : (_age_cargo_skip_counter - 1);
02217 }
02218 
02219 static const int8 _vehicle_smoke_pos[8] = {
02220   1, 1, 1, 0, -1, -1, -1, 0
02221 };
02222 
02223 static void HandleLocomotiveSmokeCloud(const Vehicle *v)
02224 {
02225   bool sound = false;
02226 
02227   if (v->vehstatus & VS_TRAIN_SLOWING || v->load_unload_time_rem != 0 || v->cur_speed < 2) {
02228     return;
02229   }
02230 
02231   const Vehicle *u = v;
02232 
02233   do {
02234     const RailVehicleInfo *rvi = RailVehInfo(v->engine_type);
02235     int effect_offset = GB(v->u.rail.cached_vis_effect, 0, 4) - 8;
02236     byte effect_type = GB(v->u.rail.cached_vis_effect, 4, 2);
02237     bool disable_effect = HasBit(v->u.rail.cached_vis_effect, 6);
02238 
02239     /* no smoke? */
02240     if ((rvi->railveh_type == RAILVEH_WAGON && effect_type == 0) ||
02241         disable_effect ||
02242         v->vehstatus & VS_HIDDEN) {
02243       continue;
02244     }
02245 
02246     /* No smoke in depots or tunnels */
02247     if (IsRailDepotTile(v->tile) || IsTunnelTile(v->tile)) continue;
02248 
02249     /* No sparks for electric vehicles on nonelectrified tracks */
02250     if (!HasPowerOnRail(v->u.rail.railtype, GetTileRailType(v->tile))) continue;
02251 
02252     if (effect_type == 0) {
02253       /* Use default effect type for engine class. */
02254       effect_type = rvi->engclass;
02255     } else {
02256       effect_type--;
02257     }
02258 
02259     int x = _vehicle_smoke_pos[v->direction] * effect_offset;
02260     int y = _vehicle_smoke_pos[(v->direction + 2) % 8] * effect_offset;
02261 
02262     if (HasBit(v->u.rail.flags, VRF_REVERSE_DIRECTION)) {
02263       x = -x;
02264       y = -y;
02265     }
02266 
02267     switch (effect_type) {
02268       case 0:
02269         /* steam smoke. */
02270         if (GB(v->tick_counter, 0, 4) == 0) {
02271           CreateEffectVehicleRel(v, x, y, 10, EV_STEAM_SMOKE);
02272           sound = true;
02273         }
02274         break;
02275 
02276       case 1:
02277         /* diesel smoke */
02278         if (u->cur_speed <= 40 && Chance16(15, 128)) {
02279           CreateEffectVehicleRel(v, 0, 0, 10, EV_DIESEL_SMOKE);
02280           sound = true;
02281         }
02282         break;
02283 
02284       case 2:
02285         /* blue spark */
02286         if (GB(v->tick_counter, 0, 2) == 0 && Chance16(1, 45)) {
02287           CreateEffectVehicleRel(v, 0, 0, 10, EV_ELECTRIC_SPARK);
02288           sound = true;
02289         }
02290         break;
02291 
02292       default:
02293         break;
02294     }
02295   } while ((v = v->Next()) != NULL);
02296 
02297   if (sound) PlayVehicleSound(u, VSE_TRAIN_EFFECT);
02298 }
02299 
02300 void Train::PlayLeaveStationSound() const
02301 {
02302   static const SoundFx sfx[] = {
02303     SND_04_TRAIN,
02304     SND_0A_TRAIN_HORN,
02305     SND_0A_TRAIN_HORN,
02306     SND_47_MAGLEV_2,
02307     SND_41_MAGLEV
02308   };
02309 
02310   if (PlayVehicleSound(this, VSE_START)) return;
02311 
02312   EngineID engtype = this->engine_type;
02313   SndPlayVehicleFx(sfx[RailVehInfo(engtype)->engclass], this);
02314 }
02315 
02317 static void CheckNextTrainTile(Vehicle *v)
02318 {
02319   /* Don't do any look-ahead if path_backoff_interval is 255. */
02320   if (_settings_game.pf.path_backoff_interval == 255) return;
02321 
02322   /* Exit if we reached our destination depot or are inside a depot. */
02323   if ((v->tile == v->dest_tile && v->current_order.IsType(OT_GOTO_DEPOT)) || v->u.rail.track & TRACK_BIT_DEPOT) return;
02324   /* Exit if we are on a station tile and are going to stop. */
02325   if (IsRailwayStationTile(v->tile) && v->current_order.ShouldStopAtStation(v, GetStationIndex(v->tile))) return;
02326   /* Exit if the current order doesn't have a destination, but the train has orders. */
02327   if ((v->current_order.IsType(OT_NOTHING) || v->current_order.IsType(OT_LEAVESTATION) || v->current_order.IsType(OT_LOADING)) && v->GetNumOrders() > 0) return;
02328 
02329   Trackdir td = GetVehicleTrackdir(v);
02330 
02331   /* On a tile with a red non-pbs signal, don't look ahead. */
02332   if (IsTileType(v->tile, MP_RAILWAY) && HasSignalOnTrackdir(v->tile, td) &&
02333       !IsPbsSignal(GetSignalType(v->tile, TrackdirToTrack(td))) &&
02334       GetSignalStateByTrackdir(v->tile, td) == SIGNAL_STATE_RED) return;
02335 
02336   CFollowTrackRail ft(v);
02337   if (!ft.Follow(v->tile, td)) return;
02338 
02339   if (!HasReservedTracks(ft.m_new_tile, TrackdirBitsToTrackBits(ft.m_new_td_bits))) {
02340     /* Next tile is not reserved. */
02341     if (KillFirstBit(ft.m_new_td_bits) == TRACKDIR_BIT_NONE) {
02342       if (HasPbsSignalOnTrackdir(ft.m_new_tile, FindFirstTrackdir(ft.m_new_td_bits))) {
02343         /* If the next tile is a PBS signal, try to make a reservation. */
02344         TrackBits tracks = TrackdirBitsToTrackBits(ft.m_new_td_bits);
02345         if (_settings_game.pf.pathfinder_for_trains != VPF_NTP && _settings_game.pf.forbid_90_deg) {
02346           tracks &= ~TrackCrossesTracks(TrackdirToTrack(ft.m_old_td));
02347         }
02348         ChooseTrainTrack(v, ft.m_new_tile, ft.m_exitdir, tracks, false, NULL, false);
02349       }
02350     }
02351   }
02352 }
02353 
02354 static bool CheckTrainStayInDepot(Vehicle *v)
02355 {
02356   /* bail out if not all wagons are in the same depot or not in a depot at all */
02357   for (const Vehicle *u = v; u != NULL; u = u->Next()) {
02358     if (u->u.rail.track != TRACK_BIT_DEPOT || u->tile != v->tile) return false;
02359   }
02360 
02361   /* if the train got no power, then keep it in the depot */
02362   if (v->u.rail.cached_power == 0) {
02363     v->vehstatus |= VS_STOPPED;
02364     InvalidateWindow(WC_VEHICLE_DEPOT, v->tile);
02365     return true;
02366   }
02367 
02368   SigSegState seg_state;
02369 
02370   if (v->u.rail.force_proceed == 0) {
02371     /* force proceed was not pressed */
02372     if (++v->load_unload_time_rem < 37) {
02373       InvalidateWindowClasses(WC_TRAINS_LIST);
02374       return true;
02375     }
02376 
02377     v->load_unload_time_rem = 0;
02378 
02379     seg_state = _settings_game.pf.reserve_paths ? SIGSEG_PBS : UpdateSignalsOnSegment(v->tile, INVALID_DIAGDIR, v->owner);
02380     if (seg_state == SIGSEG_FULL || GetDepotWaypointReservation(v->tile)) {
02381       /* Full and no PBS signal in block or depot reserved, can't exit. */
02382       InvalidateWindowClasses(WC_TRAINS_LIST);
02383       return true;
02384     }
02385   } else {
02386     seg_state = _settings_game.pf.reserve_paths ? SIGSEG_PBS : UpdateSignalsOnSegment(v->tile, INVALID_DIAGDIR, v->owner);
02387   }
02388 
02389   /* Only leave when we can reserve a path to our destination. */
02390   if (seg_state == SIGSEG_PBS && !TryPathReserve(v) && v->u.rail.force_proceed == 0) {
02391     /* No path and no force proceed. */
02392     InvalidateWindowClasses(WC_TRAINS_LIST);
02393     MarkTrainAsStuck(v);
02394     return true;
02395   }
02396 
02397   SetDepotWaypointReservation(v->tile, true);
02398   if (_settings_client.gui.show_track_reservation) MarkTileDirtyByTile(v->tile);
02399 
02400   VehicleServiceInDepot(v);
02401   InvalidateWindowClasses(WC_TRAINS_LIST);
02402   v->PlayLeaveStationSound();
02403 
02404   v->u.rail.track = TRACK_BIT_X;
02405   if (v->direction & 2) v->u.rail.track = TRACK_BIT_Y;
02406 
02407   v->vehstatus &= ~VS_HIDDEN;
02408   v->cur_speed = 0;
02409 
02410   v->UpdateDeltaXY(v->direction);
02411   v->cur_image = v->GetImage(v->direction);
02412   VehiclePositionChanged(v);
02413   UpdateSignalsOnSegment(v->tile, INVALID_DIAGDIR, v->owner);
02414   UpdateTrainAcceleration(v);
02415   InvalidateWindowData(WC_VEHICLE_DEPOT, v->tile);
02416 
02417   return false;
02418 }
02419 
02421 static void ClearPathReservation(const Vehicle *v, TileIndex tile, Trackdir track_dir)
02422 {
02423   DiagDirection dir = TrackdirToExitdir(track_dir);
02424 
02425   if (IsTileType(tile, MP_TUNNELBRIDGE)) {
02426     /* Are we just leaving a tunnel/bridge? */
02427     if (GetTunnelBridgeDirection(tile) == ReverseDiagDir(dir)) {
02428       TileIndex end = GetOtherTunnelBridgeEnd(tile);
02429 
02430       if (!HasVehicleOnTunnelBridge(tile, end, v)) {
02431         /* Free the reservation only if no other train is on the tiles. */
02432         SetTunnelBridgeReservation(tile, false);
02433         SetTunnelBridgeReservation(end, false);
02434 
02435         if (_settings_client.gui.show_track_reservation) {
02436           MarkTileDirtyByTile(tile);
02437           MarkTileDirtyByTile(end);
02438         }
02439       }
02440     }
02441   } else if (IsRailwayStationTile(tile)) {
02442     TileIndex new_tile = TileAddByDiagDir(tile, dir);
02443     /* If the new tile is not a further tile of the same station, we
02444      * clear the reservation for the whole platform. */
02445     if (!IsCompatibleTrainStationTile(new_tile, tile)) {
02446       SetRailwayStationPlatformReservation(tile, ReverseDiagDir(dir), false);
02447     }
02448   } else {
02449     /* Any other tile */
02450     UnreserveRailTrack(tile, TrackdirToTrack(track_dir));
02451   }
02452 }
02453 
02455 void FreeTrainTrackReservation(const Vehicle *v, TileIndex origin, Trackdir orig_td)
02456 {
02457   assert(IsFrontEngine(v));
02458 
02459   TileIndex tile = origin != INVALID_TILE ? origin : v->tile;
02460   Trackdir  td = orig_td != INVALID_TRACKDIR ? orig_td : GetVehicleTrackdir(v);
02461   bool      free_tile = tile != v->tile || !(IsRailwayStationTile(v->tile) || IsTileType(v->tile, MP_TUNNELBRIDGE));
02462   StationID station_id = IsRailwayStationTile(v->tile) ? GetStationIndex(v->tile) : INVALID_STATION;
02463 
02464   /* Don't free reservation if it's not ours. */
02465   if (TracksOverlap(GetReservedTrackbits(tile) | TrackToTrackBits(TrackdirToTrack(td)))) return;
02466 
02467   CFollowTrackRail ft(v, GetRailTypeInfo(v->u.rail.railtype)->compatible_railtypes);
02468   while (ft.Follow(tile, td)) {
02469     tile = ft.m_new_tile;
02470     TrackdirBits bits = ft.m_new_td_bits & TrackBitsToTrackdirBits(GetReservedTrackbits(tile));
02471     td = RemoveFirstTrackdir(&bits);
02472     assert(bits == TRACKDIR_BIT_NONE);
02473 
02474     if (!IsValidTrackdir(td)) break;
02475 
02476     if (IsTileType(tile, MP_RAILWAY)) {
02477       if (HasSignalOnTrackdir(tile, td) && !IsPbsSignal(GetSignalType(tile, TrackdirToTrack(td)))) {
02478         /* Conventional signal along trackdir: remove reservation and stop. */
02479         UnreserveRailTrack(tile, TrackdirToTrack(td));
02480         break;
02481       }
02482       if (HasPbsSignalOnTrackdir(tile, td)) {
02483         if (GetSignalStateByTrackdir(tile, td) == SIGNAL_STATE_RED) {
02484           /* Red PBS signal? Can't be our reservation, would be green then. */
02485           break;
02486         } else {
02487           /* Turn the signal back to red. */
02488           SetSignalStateByTrackdir(tile, td, SIGNAL_STATE_RED);
02489           MarkTileDirtyByTile(tile);
02490         }
02491       } else if (HasSignalOnTrackdir(tile, ReverseTrackdir(td)) && IsOnewaySignal(tile, TrackdirToTrack(td))) {
02492         break;
02493       }
02494     }
02495 
02496     /* Don't free first station/bridge/tunnel if we are on it. */
02497     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);
02498 
02499     free_tile = true;
02500   }
02501 }
02502 
02504 struct TrainTrackFollowerData {
02505   TileIndex dest_coords;
02506   StationID station_index; 
02507   uint best_bird_dist;
02508   uint best_track_dist;
02509   TrackdirByte best_track;
02510 };
02511 
02512 static bool NtpCallbFindStation(TileIndex tile, TrainTrackFollowerData *ttfd, Trackdir track, uint length)
02513 {
02514   /* heading for nowhere? */
02515   if (ttfd->dest_coords == 0) return false;
02516 
02517   /* did we reach the final station? */
02518   if ((ttfd->station_index == INVALID_STATION && tile == ttfd->dest_coords) || (
02519         IsTileType(tile, MP_STATION) &&
02520         IsRailwayStation(tile) &&
02521         GetStationIndex(tile) == ttfd->station_index
02522       )) {
02523     /* We do not check for dest_coords if we have a station_index,
02524      * because in that case the dest_coords are just an
02525      * approximation of where the station is */
02526 
02527     /* found station */
02528     ttfd->best_track = track;
02529     ttfd->best_bird_dist = 0;
02530     return true;
02531   } else {
02532     /* didn't find station, keep track of the best path so far. */
02533     uint dist = DistanceManhattan(tile, ttfd->dest_coords);
02534     if (dist < ttfd->best_bird_dist) {
02535       ttfd->best_bird_dist = dist;
02536       ttfd->best_track = track;
02537     }
02538     return false;
02539   }
02540 }
02541 
02542 static void FillWithStationData(TrainTrackFollowerData *fd, const Vehicle *v)
02543 {
02544   fd->dest_coords = v->dest_tile;
02545   fd->station_index = v->current_order.IsType(OT_GOTO_STATION) ? v->current_order.GetDestination() : INVALID_STATION;
02546 }
02547 
02548 static const byte _initial_tile_subcoord[6][4][3] = {
02549 {{ 15, 8, 1 }, { 0, 0, 0 }, { 0, 8, 5 }, { 0,  0, 0 }},
02550 {{  0, 0, 0 }, { 8, 0, 3 }, { 0, 0, 0 }, { 8, 15, 7 }},
02551 {{  0, 0, 0 }, { 7, 0, 2 }, { 0, 7, 6 }, { 0,  0, 0 }},
02552 {{ 15, 8, 2 }, { 0, 0, 0 }, { 0, 0, 0 }, { 8, 15, 6 }},
02553 {{ 15, 7, 0 }, { 8, 0, 4 }, { 0, 0, 0 }, { 0,  0, 0 }},
02554 {{  0, 0, 0 }, { 0, 0, 0 }, { 0, 8, 4 }, { 7, 15, 0 }},
02555 };
02556 
02557 static const byte _search_directions[6][4] = {
02558   { 0, 9, 2, 9 }, 
02559   { 9, 1, 9, 3 }, 
02560   { 9, 0, 3, 9 }, 
02561   { 1, 9, 9, 2 }, 
02562   { 3, 2, 9, 9 }, 
02563   { 9, 9, 1, 0 }, 
02564 };
02565 
02566 static const byte _pick_track_table[6] = {1, 3, 2, 2, 0, 0};
02567 
02580 static Track DoTrainPathfind(Vehicle *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks, bool *path_not_found, bool do_track_reservation, PBSTileInfo *dest)
02581 {
02582   Track best_track;
02583 
02584 #ifdef PF_BENCHMARK
02585   TIC()
02586 #endif
02587 
02588   if (path_not_found) *path_not_found = false;
02589 
02590   uint8 pathfinder = _settings_game.pf.pathfinder_for_trains;
02591   if (do_track_reservation && pathfinder == VPF_NTP) pathfinder = VPF_NPF;
02592 
02593   switch (pathfinder) {
02594     case VPF_YAPF: { /* YAPF */
02595       Trackdir trackdir = YapfChooseRailTrack(v, tile, enterdir, tracks, path_not_found, do_track_reservation, dest);
02596       if (trackdir != INVALID_TRACKDIR) {
02597         best_track = TrackdirToTrack(trackdir);
02598       } else {
02599         best_track = FindFirstTrack(tracks);
02600       }
02601     } break;
02602 
02603     case VPF_NPF: { /* NPF */
02604       void *perf = NpfBeginInterval();
02605 
02606       NPFFindStationOrTileData fstd;
02607       NPFFillWithOrderData(&fstd, v, do_track_reservation);
02608 
02609       PBSTileInfo origin = FollowTrainReservation(v);
02610       assert(IsValidTrackdir(origin.trackdir));
02611 
02612       NPFFoundTargetData ftd = NPFRouteToStationOrTile(origin.tile, origin.trackdir, true, &fstd, TRANSPORT_RAIL, 0, v->owner, v->u.rail.compatible_railtypes);
02613 
02614       if (dest != NULL) {
02615         dest->tile = ftd.node.tile;
02616         dest->trackdir = (Trackdir)ftd.node.direction;
02617         dest->okay = ftd.res_okay;
02618       }
02619 
02620       if (ftd.best_trackdir == INVALID_TRACKDIR) {
02621         /* We are already at our target. Just do something
02622          * @todo maybe display error?
02623          * @todo: go straight ahead if possible? */
02624         best_track = FindFirstTrack(tracks);
02625       } else {
02626         /* If ftd.best_bird_dist is 0, we found our target and ftd.best_trackdir contains
02627          * the direction we need to take to get there, if ftd.best_bird_dist is not 0,
02628          * we did not find our target, but ftd.best_trackdir contains the direction leading
02629          * to the tile closest to our target. */
02630         if (ftd.best_bird_dist != 0 && path_not_found != NULL) *path_not_found = true;
02631         /* Discard enterdir information, making it a normal track */
02632         best_track = TrackdirToTrack(ftd.best_trackdir);
02633       }
02634 
02635       int time = NpfEndInterval(perf);
02636       DEBUG(yapf, 4, "[NPFT] %d us - %d rounds - %d open - %d closed -- ", time, 0, _aystar_stats_open_size, _aystar_stats_closed_size);
02637     } break;
02638 
02639     default:
02640     case VPF_NTP: { /* NTP */
02641       void *perf = NpfBeginInterval();
02642 
02643       TrainTrackFollowerData fd;
02644       FillWithStationData(&fd, v);
02645 
02646       /* New train pathfinding */
02647       fd.best_bird_dist = UINT_MAX;
02648       fd.best_track_dist = UINT_MAX;
02649       fd.best_track = INVALID_TRACKDIR;
02650 
02651       NewTrainPathfind(tile - TileOffsByDiagDir(enterdir), v->dest_tile,
02652         v->u.rail.compatible_railtypes, enterdir, (NTPEnumProc*)NtpCallbFindStation, &fd);
02653 
02654       /* check whether the path was found or only 'guessed' */
02655       if (fd.best_bird_dist != 0 && path_not_found != NULL) *path_not_found = true;
02656 
02657       if (fd.best_track == INVALID_TRACKDIR) {
02658         /* blaha */
02659         best_track = FindFirstTrack(tracks);
02660       } else {
02661         best_track = TrackdirToTrack(fd.best_track);
02662       }
02663 
02664       int time = NpfEndInterval(perf);
02665       DEBUG(yapf, 4, "[NTPT] %d us - %d rounds - %d open - %d closed -- ", time, 0, 0, 0);
02666     } break;
02667   }
02668 
02669 #ifdef PF_BENCHMARK
02670   TOC("PF time = ", 1)
02671 #endif
02672 
02673   return best_track;
02674 }
02675 
02681 static PBSTileInfo ExtendTrainReservation(const Vehicle *v, TrackBits *new_tracks, DiagDirection *enterdir)
02682 {
02683   bool no_90deg_turns = _settings_game.pf.pathfinder_for_trains != VPF_NTP && _settings_game.pf.forbid_90_deg;
02684   PBSTileInfo origin = FollowTrainReservation(v);
02685 
02686   CFollowTrackRail ft(v);
02687 
02688   TileIndex tile = origin.tile;
02689   Trackdir  cur_td = origin.trackdir;
02690   while (ft.Follow(tile, cur_td)) {
02691     if (KillFirstBit(ft.m_new_td_bits) == TRACKDIR_BIT_NONE) {
02692       /* Possible signal tile. */
02693       if (HasOnewaySignalBlockingTrackdir(ft.m_new_tile, FindFirstTrackdir(ft.m_new_td_bits))) break;
02694     }
02695 
02696     if (no_90deg_turns) {
02697       ft.m_new_td_bits &= ~TrackdirCrossesTrackdirs(ft.m_old_td);
02698       if (ft.m_new_td_bits == TRACKDIR_BIT_NONE) break;
02699     }
02700 
02701     /* Station, depot or waypoint are a possible target. */
02702     bool target_seen = ft.m_is_station || (IsTileType(ft.m_new_tile, MP_RAILWAY) && !IsPlainRailTile(ft.m_new_tile));
02703     if (target_seen || KillFirstBit(ft.m_new_td_bits) != TRACKDIR_BIT_NONE) {
02704       /* Choice found or possible target encountered.
02705        * On finding a possible target, we need to stop and let the pathfinder handle the
02706        * remaining path. This is because we don't know if this target is in one of our
02707        * orders, so we might cause pathfinding to fail later on if we find a choice.
02708        * This failure would cause a bogous call to TryReserveSafePath which might reserve
02709        * a wrong path not leading to our next destination. */
02710       if (HasReservedTracks(ft.m_new_tile, TrackdirBitsToTrackBits(TrackdirReachesTrackdirs(ft.m_old_td)))) break;
02711 
02712       /* If we did skip some tiles, backtrack to the first skipped tile so the pathfinder
02713        * actually starts its search at the first unreserved tile. */
02714       if (ft.m_tiles_skipped != 0) ft.m_new_tile -= TileOffsByDiagDir(ft.m_exitdir) * ft.m_tiles_skipped;
02715 
02716       /* Choice found, path valid but not okay. Save info about the choice tile as well. */
02717       if (new_tracks) *new_tracks = TrackdirBitsToTrackBits(ft.m_new_td_bits);
02718       if (enterdir) *enterdir = ft.m_exitdir;
02719       return PBSTileInfo(ft.m_new_tile, ft.m_old_td, false);
02720     }
02721 
02722     tile = ft.m_new_tile;
02723     cur_td = FindFirstTrackdir(ft.m_new_td_bits);
02724 
02725     if (IsSafeWaitingPosition(v, tile, cur_td, true, no_90deg_turns)) {
02726       bool wp_free = IsWaitingPositionFree(v, tile, cur_td, no_90deg_turns);
02727       if (!(wp_free && TryReserveRailTrack(tile, TrackdirToTrack(cur_td)))) break;
02728       /* Safe position is all good, path valid and okay. */
02729       return PBSTileInfo(tile, cur_td, true);
02730     }
02731 
02732     if (!TryReserveRailTrack(tile, TrackdirToTrack(cur_td))) break;
02733   }
02734 
02735   if (ft.m_err == CFollowTrackRail::EC_OWNER || ft.m_err == CFollowTrackRail::EC_NO_WAY) {
02736     /* End of line, path valid and okay. */
02737     return PBSTileInfo(ft.m_old_tile, ft.m_old_td, true);
02738   }
02739 
02740   /* Sorry, can't reserve path, back out. */
02741   tile = origin.tile;
02742   cur_td = origin.trackdir;
02743   TileIndex stopped = ft.m_old_tile;
02744   Trackdir  stopped_td = ft.m_old_td;
02745   while (tile != stopped || cur_td != stopped_td) {
02746     if (!ft.Follow(tile, cur_td)) break;
02747 
02748     if (no_90deg_turns) {
02749       ft.m_new_td_bits &= ~TrackdirCrossesTrackdirs(ft.m_old_td);
02750       assert(ft.m_new_td_bits != TRACKDIR_BIT_NONE);
02751     }
02752     assert(KillFirstBit(ft.m_new_td_bits) == TRACKDIR_BIT_NONE);
02753 
02754     tile = ft.m_new_tile;
02755     cur_td = FindFirstTrackdir(ft.m_new_td_bits);
02756 
02757     UnreserveRailTrack(tile, TrackdirToTrack(cur_td));
02758   }
02759 
02760   /* Path invalid. */
02761   return PBSTileInfo();
02762 }
02763 
02774 static bool TryReserveSafeTrack(const Vehicle *v, TileIndex tile, Trackdir td, bool override_tailtype)
02775 {
02776   if (_settings_game.pf.pathfinder_for_trains == VPF_YAPF) {
02777     return YapfRailFindNearestSafeTile(v, tile, td, override_tailtype);
02778   } else {
02779     return NPFRouteToSafeTile(v, tile, td, override_tailtype).res_okay;
02780   }
02781 }
02782 
02784 class VehicleOrderSaver
02785 {
02786 private:
02787   Vehicle        *v;
02788   Order          old_order;
02789   TileIndex      old_dest_tile;
02790   StationID      old_last_station_visited;
02791   VehicleOrderID index;
02792 
02793 public:
02794   VehicleOrderSaver(Vehicle *_v) :
02795     v(_v),
02796     old_order(_v->current_order),
02797     old_dest_tile(_v->dest_tile),
02798     old_last_station_visited(_v->last_station_visited),
02799     index(_v->cur_order_index)
02800   {
02801   }
02802 
02803   ~VehicleOrderSaver()
02804   {
02805     this->v->current_order = this->old_order;
02806     this->v->dest_tile = this->old_dest_tile;
02807     this->v->last_station_visited = this->old_last_station_visited;
02808   }
02809 
02815   bool SwitchToNextOrder(bool skip_first)
02816   {
02817     if (this->v->GetNumOrders() == 0) return false;
02818 
02819     if (skip_first) ++this->index;
02820 
02821     int conditional_depth = 0;
02822 
02823     do {
02824       /* Wrap around. */
02825       if (this->index >= this->v->GetNumOrders()) this->index = 0;
02826 
02827       Order *order = GetVehicleOrder(this->v, this->index);
02828       assert(order != NULL);
02829 
02830       switch (order->GetType()) {
02831         case OT_GOTO_DEPOT:
02832           /* Skip service in depot orders when the train doesn't need service. */
02833           if ((order->GetDepotOrderType() & ODTFB_SERVICE) && !this->v->NeedsServicing()) break;
02834         case OT_GOTO_STATION:
02835         case OT_GOTO_WAYPOINT:
02836           this->v->current_order = *order;
02837           UpdateOrderDest(this->v, order);
02838           return true;
02839         case OT_CONDITIONAL: {
02840           if (conditional_depth > this->v->GetNumOrders()) return false;
02841           VehicleOrderID next = ProcessConditionalOrder(order, this->v);
02842           if (next != INVALID_VEH_ORDER_ID) {
02843             conditional_depth++;
02844             this->index = next;
02845             /* Don't increment next, so no break here. */
02846             continue;
02847           }
02848           break;
02849         }
02850         default:
02851           break;
02852       }
02853       /* Don't increment inside the while because otherwise conditional
02854        * orders can lead to an infinite loop. */
02855       ++this->index;
02856     } while (this->index != this->v->cur_order_index);
02857 
02858     return false;
02859   }
02860 };
02861 
02862 /* choose a track */
02863 static Track ChooseTrainTrack(Vehicle *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks, bool force_res, bool *got_reservation, bool mark_stuck)
02864 {
02865   Track best_track = INVALID_TRACK;
02866   bool do_track_reservation = _settings_game.pf.reserve_paths || force_res;
02867   bool changed_signal = false;
02868 
02869   assert((tracks & ~TRACK_BIT_MASK) == 0);
02870 
02871   if (got_reservation != NULL) *got_reservation = false;
02872 
02873   /* Don't use tracks here as the setting to forbid 90 deg turns might have been switched between reservation and now. */
02874   TrackBits res_tracks = (TrackBits)(GetReservedTrackbits(tile) & DiagdirReachesTracks(enterdir));
02875   /* Do we have a suitable reserved track? */
02876   if (res_tracks != TRACK_BIT_NONE) return FindFirstTrack(res_tracks);
02877 
02878   /* Quick return in case only one possible track is available */
02879   if (KillFirstBit(tracks) == TRACK_BIT_NONE) {
02880     Track track = FindFirstTrack(tracks);
02881     /* We need to check for signals only here, as a junction tile can't have signals. */
02882     if (track != INVALID_TRACK && HasPbsSignalOnTrackdir(tile, TrackEnterdirToTrackdir(track, enterdir))) {
02883       do_track_reservation = true;
02884       changed_signal = true;
02885       SetSignalStateByTrackdir(tile, TrackEnterdirToTrackdir(track, enterdir), SIGNAL_STATE_GREEN);
02886     } else if (!do_track_reservation) {
02887       return track;
02888     }
02889     best_track = track;
02890   }
02891 
02892   PBSTileInfo   res_dest(tile, INVALID_TRACKDIR, false);
02893   DiagDirection dest_enterdir = enterdir;
02894   if (do_track_reservation) {
02895     /* Check if the train needs service here, so it has a chance to always find a depot.
02896      * Also check if the current order is a service order so we don't reserve a path to
02897      * the destination but instead to the next one if service isn't needed. */
02898     CheckIfTrainNeedsService(v);
02899     if (v->current_order.IsType(OT_DUMMY) || v->current_order.IsType(OT_CONDITIONAL) || v->current_order.IsType(OT_GOTO_DEPOT)) ProcessOrders(v);
02900 
02901     res_dest = ExtendTrainReservation(v, &tracks, &dest_enterdir);
02902     if (res_dest.tile == INVALID_TILE) {
02903       /* Reservation failed? */
02904       if (mark_stuck) MarkTrainAsStuck(v);
02905       if (changed_signal) SetSignalStateByTrackdir(tile, TrackEnterdirToTrackdir(best_track, enterdir), SIGNAL_STATE_RED);
02906       return FindFirstTrack(tracks);
02907     }
02908   }
02909 
02910   /* Save the current train order. The destructor will restore the old order on function exit. */
02911   VehicleOrderSaver orders(v);
02912 
02913   /* If the current tile is the destination of the current order and
02914    * a reservation was requested, advance to the next order.
02915    * Don't advance on a depot order as depots are always safe end points
02916    * for a path and no look-ahead is necessary. This also avoids a
02917    * problem with depot orders not part of the order list when the
02918    * order list itself is empty. */
02919   if (v->current_order.IsType(OT_LEAVESTATION)) {
02920     orders.SwitchToNextOrder(false);
02921   } else if (v->current_order.IsType(OT_LOADING) || (!v->current_order.IsType(OT_GOTO_DEPOT) && (
02922       v->current_order.IsType(OT_GOTO_STATION) ?
02923       IsRailwayStationTile(v->tile) && v->current_order.GetDestination() == GetStationIndex(v->tile) :
02924       v->tile == v->dest_tile))) {
02925     orders.SwitchToNextOrder(true);
02926   }
02927 
02928   if (res_dest.tile != INVALID_TILE && !res_dest.okay) {
02929     /* Pathfinders are able to tell that route was only 'guessed'. */
02930     bool      path_not_found = false;
02931     TileIndex new_tile = res_dest.tile;
02932 
02933     Track next_track = DoTrainPathfind(v, new_tile, dest_enterdir, tracks, &path_not_found, do_track_reservation, &res_dest);
02934     if (new_tile == tile) best_track = next_track;
02935 
02936     /* handle "path not found" state */
02937     if (path_not_found) {
02938       /* PF didn't find the route */
02939       if (!HasBit(v->u.rail.flags, VRF_NO_PATH_TO_DESTINATION)) {
02940         /* it is first time the problem occurred, set the "path not found" flag */
02941         SetBit(v->u.rail.flags, VRF_NO_PATH_TO_DESTINATION);
02942         /* and notify user about the event */
02943         AI::NewEvent(v->owner, new AIEventVehicleLost(v->index));
02944         if (_settings_client.gui.lost_train_warn && v->owner == _local_company) {
02945           SetDParam(0, v->index);
02946           AddNewsItem(
02947             STR_TRAIN_IS_LOST,
02948             NS_ADVICE,
02949             v->index,
02950             0);
02951         }
02952       }
02953     } else {
02954       /* route found, is the train marked with "path not found" flag? */
02955       if (HasBit(v->u.rail.flags, VRF_NO_PATH_TO_DESTINATION)) {
02956         /* clear the flag as the PF's problem was solved */
02957         ClrBit(v->u.rail.flags, VRF_NO_PATH_TO_DESTINATION);
02958         /* can we also delete the "News" item somehow? */
02959       }
02960     }
02961   }
02962 
02963   /* No track reservation requested -> finished. */
02964   if (!do_track_reservation) return best_track;
02965 
02966   /* A path was found, but could not be reserved. */
02967   if (res_dest.tile != INVALID_TILE && !res_dest.okay) {
02968     if (mark_stuck) MarkTrainAsStuck(v);
02969     FreeTrainTrackReservation(v);
02970     return best_track;
02971   }
02972 
02973   /* No possible reservation target found, we are probably lost. */
02974   if (res_dest.tile == INVALID_TILE) {
02975     /* Try to find any safe destination. */
02976     PBSTileInfo origin = FollowTrainReservation(v);
02977     if (TryReserveSafeTrack(v, origin.tile, origin.trackdir, false)) {
02978       TrackBits res = GetReservedTrackbits(tile) & DiagdirReachesTracks(enterdir);
02979       best_track = FindFirstTrack(res);
02980       TryReserveRailTrack(v->tile, TrackdirToTrack(GetVehicleTrackdir(v)));
02981       if (got_reservation != NULL) *got_reservation = true;
02982       if (changed_signal) MarkTileDirtyByTile(tile);
02983     } else {
02984       FreeTrainTrackReservation(v);
02985       if (mark_stuck) MarkTrainAsStuck(v);
02986     }
02987     return best_track;
02988   }
02989 
02990   if (got_reservation != NULL) *got_reservation = true;
02991 
02992   /* Reservation target found and free, check if it is safe. */
02993   while (!IsSafeWaitingPosition(v, res_dest.tile, res_dest.trackdir, true, _settings_game.pf.forbid_90_deg)) {
02994     /* Extend reservation until we have found a safe position. */
02995     DiagDirection exitdir = TrackdirToExitdir(res_dest.trackdir);
02996     TileIndex     next_tile = TileAddByDiagDir(res_dest.tile, exitdir);
02997     TrackBits     reachable = TrackdirBitsToTrackBits((TrackdirBits)(GetTileTrackStatus(next_tile, TRANSPORT_RAIL, 0))) & DiagdirReachesTracks(exitdir);
02998     if (_settings_game.pf.pathfinder_for_trains != VPF_NTP && _settings_game.pf.forbid_90_deg) {
02999       reachable &= ~TrackCrossesTracks(TrackdirToTrack(res_dest.trackdir));
03000     }
03001 
03002     /* Get next order with destination. */
03003     if (orders.SwitchToNextOrder(true)) {
03004       PBSTileInfo cur_dest;
03005       DoTrainPathfind(v, next_tile, exitdir, reachable, NULL, true, &cur_dest);
03006       if (cur_dest.tile != INVALID_TILE) {
03007         res_dest = cur_dest;
03008         if (res_dest.okay) continue;
03009         /* Path found, but could not be reserved. */
03010         FreeTrainTrackReservation(v);
03011         if (mark_stuck) MarkTrainAsStuck(v);
03012         if (got_reservation != NULL) *got_reservation = false;
03013         changed_signal = false;
03014         break;
03015       }
03016     }
03017     /* No order or no safe position found, try any position. */
03018     if (!TryReserveSafeTrack(v, res_dest.tile, res_dest.trackdir, true)) {
03019       FreeTrainTrackReservation(v);
03020       if (mark_stuck) MarkTrainAsStuck(v);
03021       if (got_reservation != NULL) *got_reservation = false;
03022       changed_signal = false;
03023     }
03024     break;
03025   }
03026 
03027   TryReserveRailTrack(v->tile, TrackdirToTrack(GetVehicleTrackdir(v)));
03028 
03029   if (changed_signal) MarkTileDirtyByTile(tile);
03030 
03031   return best_track;
03032 }
03033 
03042 bool TryPathReserve(Vehicle *v, bool mark_as_stuck, bool first_tile_okay)
03043 {
03044   assert(v->type == VEH_TRAIN && IsFrontEngine(v));
03045 
03046   /* We have to handle depots specially as the track follower won't look
03047    * at the depot tile itself but starts from the next tile. If we are still
03048    * inside the depot, a depot reservation can never be ours. */
03049   if (v->u.rail.track & TRACK_BIT_DEPOT) {
03050     if (GetDepotWaypointReservation(v->tile)) {
03051       if (mark_as_stuck) MarkTrainAsStuck(v);
03052       return false;
03053     } else {
03054       /* Depot not reserved, but the next tile might be. */
03055       TileIndex next_tile = TileAddByDiagDir(v->tile, GetRailDepotDirection(v->tile));
03056       if (HasReservedTracks(next_tile, DiagdirReachesTracks(GetRailDepotDirection(v->tile)))) return false;
03057     }
03058   }
03059 
03060   /* Special check if we are in front of a two-sided conventional signal. */
03061   DiagDirection dir = TrainExitDir(v->direction, v->u.rail.track);
03062   TileIndex next_tile = TileAddByDiagDir(v->tile, dir);
03063   if (IsTileType(next_tile, MP_RAILWAY) && HasReservedTracks(next_tile, DiagdirReachesTracks(dir))) {
03064     /* Can have only one reserved trackdir. */
03065     Trackdir td = FindFirstTrackdir(TrackBitsToTrackdirBits(GetReservedTrackbits(next_tile)) & DiagdirReachesTrackdirs(dir));
03066     if (HasSignalOnTrackdir(next_tile, td) && HasSignalOnTrackdir(next_tile, ReverseTrackdir(td)) &&
03067         !IsPbsSignal(GetSignalType(next_tile, TrackdirToTrack(td)))) {
03068       /* Signal already reserved, is not ours. */
03069       if (mark_as_stuck) MarkTrainAsStuck(v);
03070       return false;
03071     }
03072   }
03073 
03074   bool other_train = false;
03075   PBSTileInfo origin = FollowTrainReservation(v, &other_train);
03076   /* If we have a reserved path and the path ends at a safe tile, we are finished already. */
03077   if (origin.okay && (v->tile != origin.tile || first_tile_okay)) {
03078     /* Can't be stuck then. */
03079     if (HasBit(v->u.rail.flags, VRF_TRAIN_STUCK)) InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
03080     ClrBit(v->u.rail.flags, VRF_TRAIN_STUCK);
03081     return true;
03082   }
03083   /* The path we are driving on is alread blocked by some other train.
03084    * This can only happen when tracks and signals are changed. A crash
03085    * is probably imminent, don't do any further reservation because
03086    * it might cause stale reservations. */
03087   if (other_train && v->tile != origin.tile) {
03088     if (mark_as_stuck) MarkTrainAsStuck(v);
03089     return false;
03090   }
03091 
03092   /* If we are in a depot, tentativly reserve the depot. */
03093   if (v->u.rail.track & TRACK_BIT_DEPOT) {
03094     SetDepotWaypointReservation(v->tile, true);
03095     if (_settings_client.gui.show_track_reservation) MarkTileDirtyByTile(v->tile);
03096   }
03097 
03098   DiagDirection exitdir = TrackdirToExitdir(origin.trackdir);
03099   TileIndex     new_tile = TileAddByDiagDir(origin.tile, exitdir);
03100   TrackBits     reachable = TrackdirBitsToTrackBits(TrackStatusToTrackdirBits(GetTileTrackStatus(new_tile, TRANSPORT_RAIL, 0)) & DiagdirReachesTrackdirs(exitdir));
03101 
03102   if (_settings_game.pf.pathfinder_for_trains != VPF_NTP && _settings_game.pf.forbid_90_deg) reachable &= ~TrackCrossesTracks(TrackdirToTrack(origin.trackdir));
03103 
03104   bool res_made = false;
03105   ChooseTrainTrack(v, new_tile, exitdir, reachable, true, &res_made, mark_as_stuck);
03106 
03107   if (!res_made) {
03108     /* Free the depot reservation as well. */
03109     if (v->u.rail.track & TRACK_BIT_DEPOT) SetDepotWaypointReservation(v->tile, false);
03110     return false;
03111   }
03112 
03113   if (HasBit(v->u.rail.flags, VRF_TRAIN_STUCK)) {
03114     v->load_unload_time_rem = 0;
03115     InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
03116   }
03117   ClrBit(v->u.rail.flags, VRF_TRAIN_STUCK);
03118   return true;
03119 }
03120 
03121 
03122 static bool CheckReverseTrain(Vehicle *v)
03123 {
03124   if (_settings_game.difficulty.line_reverse_mode != 0 ||
03125       v->u.rail.track == TRACK_BIT_DEPOT || v->u.rail.track == TRACK_BIT_WORMHOLE ||
03126       !(v->direction & 1)) {
03127     return false;
03128   }
03129 
03130   uint reverse_best = 0;
03131 
03132   assert(v->u.rail.track);
03133 
03134   switch (_settings_game.pf.pathfinder_for_trains) {
03135     case VPF_YAPF: /* YAPF */
03136       reverse_best = YapfCheckReverseTrain(v);
03137       break;
03138 
03139     case VPF_NPF: { /* NPF */
03140       NPFFindStationOrTileData fstd;
03141       NPFFoundTargetData ftd;
03142       Vehicle *last = GetLastVehicleInChain(v);
03143 
03144       NPFFillWithOrderData(&fstd, v);
03145 
03146       Trackdir trackdir = GetVehicleTrackdir(v);
03147       Trackdir trackdir_rev = ReverseTrackdir(GetVehicleTrackdir(last));
03148       assert(trackdir != INVALID_TRACKDIR);
03149       assert(trackdir_rev != INVALID_TRACKDIR);
03150 
03151       ftd = NPFRouteToStationOrTileTwoWay(v->tile, trackdir, false, last->tile, trackdir_rev, false, &fstd, TRANSPORT_RAIL, 0, v->owner, v->u.rail.compatible_railtypes);
03152       if (ftd.best_bird_dist != 0) {
03153         /* We didn't find anything, just keep on going straight ahead */
03154         reverse_best = false;
03155       } else {
03156         if (NPFGetFlag(&ftd.node, NPF_FLAG_REVERSE)) {
03157           reverse_best = true;
03158         } else {
03159           reverse_best = false;
03160         }
03161       }
03162     } break;
03163 
03164     default:
03165     case VPF_NTP: { /* NTP */
03166       TrainTrackFollowerData fd;
03167       FillWithStationData(&fd, v);
03168 
03169       int i = _search_directions[FindFirstTrack(v->u.rail.track)][DirToDiagDir(v->direction)];
03170 
03171       int best_track = -1;
03172       uint reverse = 0;
03173       uint best_bird_dist  = 0;
03174       uint best_track_dist = 0;
03175 
03176       for (;;) {
03177         fd.best_bird_dist = UINT_MAX;
03178         fd.best_track_dist = UINT_MAX;
03179 
03180         NewTrainPathfind(v->tile, v->dest_tile, v->u.rail.compatible_railtypes, (DiagDirection)(reverse ^ i), (NTPEnumProc*)NtpCallbFindStation, &fd);
03181 
03182         if (best_track != -1) {
03183           if (best_bird_dist != 0) {
03184             if (fd.best_bird_dist != 0) {
03185               /* neither reached the destination, pick the one with the smallest bird dist */
03186               if (fd.best_bird_dist > best_bird_dist) goto bad;
03187               if (fd.best_bird_dist < best_bird_dist) goto good;
03188             } else {
03189               /* we found the destination for the first time */
03190               goto good;
03191             }
03192           } else {
03193             if (fd.best_bird_dist != 0) {
03194               /* didn't find destination, but we've found the destination previously */
03195               goto bad;
03196             } else {
03197               /* both old & new reached the destination, compare track length */
03198               if (fd.best_track_dist > best_track_dist) goto bad;
03199               if (fd.best_track_dist < best_track_dist) goto good;
03200             }
03201           }
03202 
03203           /* if we reach this position, there's two paths of equal value so far.
03204            * pick one randomly. */
03205           int r = GB(Random(), 0, 8);
03206           if (_pick_track_table[i] == (v->direction & 3)) r += 80;
03207           if (_pick_track_table[best_track] == (v->direction & 3)) r -= 80;
03208           if (r <= 127) goto bad;
03209         }
03210 good:;
03211         best_track = i;
03212         best_bird_dist = fd.best_bird_dist;
03213         best_track_dist = fd.best_track_dist;
03214         reverse_best = reverse;
03215 bad:;
03216         if (reverse != 0) break;
03217         reverse = 2;
03218       }
03219     } break;
03220   }
03221 
03222   return reverse_best != 0;
03223 }
03224 
03225 TileIndex Train::GetOrderStationLocation(StationID station)
03226 {
03227   if (station == this->last_station_visited) this->last_station_visited = INVALID_STATION;
03228 
03229   const Station *st = GetStation(station);
03230   if (!(st->facilities & FACIL_TRAIN)) {
03231     /* The destination station has no trainstation tiles. */
03232     this->cur_order_index++;
03233     return 0;
03234   }
03235 
03236   return st->xy;
03237 }
03238 
03239 void Train::MarkDirty()
03240 {
03241   Vehicle *v = this;
03242   do {
03243     v->cur_image = v->GetImage(v->direction);
03244     MarkSingleVehicleDirty(v);
03245   } while ((v = v->Next()) != NULL);
03246 
03247   /* need to update acceleration and cached values since the goods on the train changed. */
03248   TrainCargoChanged(this);
03249   UpdateTrainAcceleration(this);
03250 }
03251 
03262 static int UpdateTrainSpeed(Vehicle *v)
03263 {
03264   uint accel;
03265 
03266   if (v->vehstatus & VS_STOPPED || HasBit(v->u.rail.flags, VRF_REVERSING) || HasBit(v->u.rail.flags, VRF_TRAIN_STUCK)) {
03267     switch (_settings_game.vehicle.train_acceleration_model) {
03268       default: NOT_REACHED();
03269       case TAM_ORIGINAL:  accel = v->acceleration * -4; break;
03270       case TAM_REALISTIC: accel = GetTrainAcceleration(v, AM_BRAKE); break;
03271     }
03272   } else {
03273     switch (_settings_game.vehicle.train_acceleration_model) {
03274       default: NOT_REACHED();
03275       case TAM_ORIGINAL:  accel = v->acceleration * 2; break;
03276       case TAM_REALISTIC: accel = GetTrainAcceleration(v, AM_ACCEL); break;
03277     }
03278   }
03279 
03280   uint spd = v->subspeed + accel;
03281   v->subspeed = (byte)spd;
03282   {
03283     int tempmax = v->max_speed;
03284     if (v->cur_speed > v->max_speed)
03285       tempmax = v->cur_speed - (v->cur_speed / 10) - 1;
03286     v->cur_speed = spd = Clamp(v->cur_speed + ((int)spd >> 8), 0, tempmax);
03287   }
03288 
03289   /* Scale speed by 3/4. Previously this was only done when the train was
03290    * facing diagonally and would apply to however many moves the train made
03291    * regardless the of direction actually moved in. Now it is always scaled,
03292    * 256 spd is used to go straight and 192 is used to go diagonally
03293    * (3/4 of 256). This results in the same effect, but without the error the
03294    * previous method caused.
03295    *
03296    * The scaling is done in this direction and not by multiplying the amount
03297    * to be subtracted by 4/3 so that the leftover speed can be saved in a
03298    * byte in v->progress.
03299    */
03300   int scaled_spd = spd * 3 >> 2;
03301 
03302   scaled_spd += v->progress;
03303   v->progress = 0; // set later in TrainLocoHandler or TrainController
03304   return scaled_spd;
03305 }
03306 
03307 static void TrainEnterStation(Vehicle *v, StationID station)
03308 {
03309   v->last_station_visited = station;
03310 
03311   /* check if a train ever visited this station before */
03312   Station *st = GetStation(station);
03313   if (!(st->had_vehicle_of_type & HVOT_TRAIN)) {
03314     st->had_vehicle_of_type |= HVOT_TRAIN;
03315     SetDParam(0, st->index);
03316     AddNewsItem(
03317       STR_8801_CITIZENS_CELEBRATE_FIRST,
03318       v->owner == _local_company ? NS_ARRIVAL_COMPANY : NS_ARRIVAL_OTHER,
03319       v->index,
03320       st->index
03321     );
03322     AI::NewEvent(v->owner, new AIEventStationFirstVehicle(st->index, v->index));
03323   }
03324 
03325   v->BeginLoading();
03326 
03327   StationAnimationTrigger(st, v->tile, STAT_ANIM_TRAIN_ARRIVES);
03328 }
03329 
03330 static byte AfterSetTrainPos(Vehicle *v, bool new_tile)
03331 {
03332   byte old_z = v->z_pos;
03333   v->z_pos = GetSlopeZ(v->x_pos, v->y_pos);
03334 
03335   if (new_tile) {
03336     ClrBit(v->u.rail.flags, VRF_GOINGUP);
03337     ClrBit(v->u.rail.flags, VRF_GOINGDOWN);
03338 
03339     if (v->u.rail.track == TRACK_BIT_X || v->u.rail.track == TRACK_BIT_Y) {
03340       /* Any track that isn't TRACK_BIT_X or TRACK_BIT_Y cannot be sloped.
03341        * To check whether the current tile is sloped, and in which
03342        * direction it is sloped, we get the 'z' at the center of
03343        * the tile (middle_z) and the edge of the tile (old_z),
03344        * which we then can compare. */
03345       static const int HALF_TILE_SIZE = TILE_SIZE / 2;
03346       static const int INV_TILE_SIZE_MASK = ~(TILE_SIZE - 1);
03347 
03348       byte middle_z = GetSlopeZ((v->x_pos & INV_TILE_SIZE_MASK) | HALF_TILE_SIZE, (v->y_pos & INV_TILE_SIZE_MASK) | HALF_TILE_SIZE);
03349 
03350       /* For some reason tunnel tiles are always given as sloped :(
03351        * But they are not sloped... */
03352       if (middle_z != v->z_pos && !IsTunnelTile(TileVirtXY(v->x_pos, v->y_pos))) {
03353         SetBit(v->u.rail.flags, (middle_z > old_z) ? VRF_GOINGUP : VRF_GOINGDOWN);
03354       }
03355     }
03356   }
03357 
03358   VehiclePositionChanged(v);
03359   EndVehicleMove(v);
03360   return old_z;
03361 }
03362 
03363 static const Direction _new_vehicle_direction_table[11] = {
03364   DIR_N , DIR_NW, DIR_W , INVALID_DIR,
03365   DIR_NE, DIR_N , DIR_SW, INVALID_DIR,
03366   DIR_E , DIR_SE, DIR_S
03367 };
03368 
03369 static inline Direction GetNewVehicleDirectionByTile(TileIndex new_tile, TileIndex old_tile)
03370 {
03371   uint offs = (TileY(new_tile) - TileY(old_tile) + 1) * 4 +
03372               TileX(new_tile) - TileX(old_tile) + 1;
03373   assert(offs < 11);
03374   return _new_vehicle_direction_table[offs];
03375 }
03376 
03377 static inline int GetDirectionToVehicle(const Vehicle *v, int x, int y)
03378 {
03379   byte offs;
03380 
03381   x -= v->x_pos;
03382   if (x >= 0) {
03383     offs = (x > 2) ? 0 : 1;
03384   } else {
03385     offs = (x < -2) ? 2 : 1;
03386   }
03387 
03388   y -= v->y_pos;
03389   if (y >= 0) {
03390     offs += ((y > 2) ? 0 : 1) * 4;
03391   } else {
03392     offs += ((y < -2) ? 2 : 1) * 4;
03393   }
03394 
03395   assert(offs < 11);
03396   return _new_vehicle_direction_table[offs];
03397 }
03398 
03399 /* Check if the vehicle is compatible with the specified tile */
03400 static inline bool CheckCompatibleRail(const Vehicle *v, TileIndex tile)
03401 {
03402   return
03403     IsTileOwner(tile, v->owner) && (
03404       !IsFrontEngine(v) ||
03405       HasBit(v->u.rail.compatible_railtypes, GetRailType(tile))
03406     );
03407 }
03408 
03409 struct RailtypeSlowdownParams {
03410   byte small_turn, large_turn;
03411   byte z_up; // fraction to remove when moving up
03412   byte z_down; // fraction to remove when moving down
03413 };
03414 
03415 static const RailtypeSlowdownParams _railtype_slowdown[] = {
03416   // normal accel
03417   {256 / 4, 256 / 2, 256 / 4, 2}, 
03418   {256 / 4, 256 / 2, 256 / 4, 2}, 
03419   {256 / 4, 256 / 2, 256 / 4, 2}, 
03420   {0,       256 / 2, 256 / 4, 2}, 
03421 };
03422 
03424 static inline void AffectSpeedByDirChange(Vehicle *v, Direction new_dir)
03425 {
03426   if (_settings_game.vehicle.train_acceleration_model != TAM_ORIGINAL) return;
03427 
03428   DirDiff diff = DirDifference(v->direction, new_dir);
03429   if (diff == DIRDIFF_SAME) return;
03430 
03431   const RailtypeSlowdownParams *rsp = &_railtype_slowdown[v->u.rail.railtype];
03432   v->cur_speed -= (diff == DIRDIFF_45RIGHT || diff == DIRDIFF_45LEFT ? rsp->small_turn : rsp->large_turn) * v->cur_speed >> 8;
03433 }
03434 
03436 static inline void AffectSpeedByZChange(Vehicle *v, byte old_z)
03437 {
03438   if (old_z == v->z_pos || _settings_game.vehicle.train_acceleration_model != TAM_ORIGINAL) return;
03439 
03440   const RailtypeSlowdownParams *rsp = &_railtype_slowdown[v->u.rail.railtype];
03441 
03442   if (old_z < v->z_pos) {
03443     v->cur_speed -= (v->cur_speed * rsp->z_up >> 8);
03444   } else {
03445     uint16 spd = v->cur_speed + rsp->z_down;
03446     if (spd <= v->max_speed) v->cur_speed = spd;
03447   }
03448 }
03449 
03450 static bool TrainMovedChangeSignals(TileIndex tile, DiagDirection dir)
03451 {
03452   if (IsTileType(tile, MP_RAILWAY) &&
03453       GetRailTileType(tile) == RAIL_TILE_SIGNALS) {
03454     TrackdirBits tracks = TrackBitsToTrackdirBits(GetTrackBits(tile)) & DiagdirReachesTrackdirs(dir);
03455     Trackdir trackdir = FindFirstTrackdir(tracks);
03456     if (UpdateSignalsOnSegment(tile,  TrackdirToExitdir(trackdir), GetTileOwner(tile)) == SIGSEG_PBS && HasSignalOnTrackdir(tile, trackdir)) {
03457       /* A PBS block with a non-PBS signal facing us? */
03458       if (!IsPbsSignal(GetSignalType(tile, TrackdirToTrack(trackdir)))) return true;
03459     }
03460   }
03461   return false;
03462 }
03463 
03464 
03465 static void SetVehicleCrashed(Vehicle *v)
03466 {
03467   if (v->u.rail.crash_anim_pos != 0) return;
03468 
03469   /* Free a possible path reservation and try to mark all tiles occupied by the train reserved. */
03470   if (IsFrontEngine(v)) {
03471     /* Remove all reservations, also the ones currently under the train
03472      * and any railway station paltform reservation. */
03473     FreeTrainTrackReservation(v);
03474     for (const Vehicle *u = v; u != NULL; u = u->Next()) {
03475       ClearPathReservation(u, u->tile, GetVehicleTrackdir(u));
03476       if (IsTileType(u->tile, MP_TUNNELBRIDGE)) {
03477         /* ClearPathReservation will not free the wormhole exit
03478          * if the train has just entered the wormhole. */
03479         SetTunnelBridgeReservation(GetOtherTunnelBridgeEnd(u->tile), false);
03480       }
03481     }
03482   }
03483 
03484   /* we may need to update crossing we were approaching */
03485   TileIndex crossing = TrainApproachingCrossingTile(v);
03486 
03487   v->u.rail.crash_anim_pos++;
03488 
03489   InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
03490   InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
03491 
03492   if (v->u.rail.track == TRACK_BIT_DEPOT) {
03493     InvalidateWindow(WC_VEHICLE_DEPOT, v->tile);
03494   }
03495 
03496   InvalidateWindowClassesData(WC_TRAINS_LIST, 0);
03497 
03498   for (; v != NULL; v = v->Next()) {
03499     v->vehstatus |= VS_CRASHED;
03500     MarkSingleVehicleDirty(v);
03501   }
03502 
03503   /* must be updated after the train has been marked crashed */
03504   if (crossing != INVALID_TILE) UpdateLevelCrossing(crossing);
03505 }
03506 
03507 static uint CountPassengersInTrain(const Vehicle *v)
03508 {
03509   uint num = 0;
03510 
03511   for (; v != NULL; v = v->Next()) {
03512     if (IsCargoInClass(v->cargo_type, CC_PASSENGERS)) num += v->cargo.Count();
03513   }
03514 
03515   return num;
03516 }
03517 
03524 static uint TrainCrashed(Vehicle *v)
03525 {
03526   /* do not crash train twice */
03527   if (v->vehstatus & VS_CRASHED) return 0;
03528 
03529   /* two drivers + passengers */
03530   uint num = 2 + CountPassengersInTrain(v);
03531 
03532   SetVehicleCrashed(v);
03533   AI::NewEvent(v->owner, new AIEventVehicleCrashed(v->index, v->tile, AIEventVehicleCrashed::CRASH_TRAIN));
03534 
03535   return num;
03536 }
03537 
03538 struct TrainCollideChecker {
03539   Vehicle *v;  
03540   uint num;    
03541 };
03542 
03543 static Vehicle *FindTrainCollideEnum(Vehicle *v, void *data)
03544 {
03545   TrainCollideChecker *tcc = (TrainCollideChecker*)data;
03546 
03547   if (v->type != VEH_TRAIN) return NULL;
03548 
03549   /* get first vehicle now to make most usual checks faster */
03550   Vehicle *coll = v->First();
03551 
03552   /* can't collide with own wagons && can't crash in depot && the same height level */
03553   if (coll != tcc->v && v->u.rail.track != TRACK_BIT_DEPOT && abs(v->z_pos - tcc->v->z_pos) < 6) {
03554     int x_diff = v->x_pos - tcc->v->x_pos;
03555     int y_diff = v->y_pos - tcc->v->y_pos;
03556 
03557     /* needed to disable possible crash of competitor train in station by building diagonal track at its end */
03558     if (x_diff * x_diff + y_diff * y_diff > 25) return NULL;
03559 
03560     /* crash both trains */
03561     tcc->num += TrainCrashed(tcc->v);
03562     tcc->num += TrainCrashed(coll);
03563 
03564     /* Try to reserve all tiles directly under the crashed trains.
03565      * As there might be more than two trains involved, we have to do that for all vehicles */
03566     const Vehicle *u;
03567     FOR_ALL_VEHICLES(u) {
03568       if (u->type == VEH_TRAIN && HASBITS(u->vehstatus, VS_CRASHED) && (u->u.rail.track & TRACK_BIT_DEPOT) == TRACK_BIT_NONE) {
03569         TrackBits trackbits = u->u.rail.track;
03570         if ((trackbits & TRACK_BIT_WORMHOLE) == TRACK_BIT_WORMHOLE) {
03571           /* Vehicle is inside a wormhole, v->u.rail.track contains no useful value then. */
03572           trackbits |= DiagDirToDiagTrackBits(GetTunnelBridgeDirection(u->tile));
03573         }
03574         TryReserveRailTrack(u->tile, TrackBitsToTrack(trackbits));
03575       }
03576     }
03577   }
03578 
03579   return NULL;
03580 }
03581 
03588 static bool CheckTrainCollision(Vehicle *v)
03589 {
03590   /* can't collide in depot */
03591   if (v->u.rail.track == TRACK_BIT_DEPOT) return false;
03592 
03593   assert(v->u.rail.track == TRACK_BIT_WORMHOLE || TileVirtXY(v->x_pos, v->y_pos) == v->tile);
03594 
03595   TrainCollideChecker tcc;
03596   tcc.v = v;
03597   tcc.num = 0;
03598 
03599   /* find colliding vehicles */
03600   if (v->u.rail.track == TRACK_BIT_WORMHOLE) {
03601     FindVehicleOnPos(v->tile, &tcc, FindTrainCollideEnum);
03602     FindVehicleOnPos(GetOtherTunnelBridgeEnd(v->tile), &tcc, FindTrainCollideEnum);
03603   } else {
03604     FindVehicleOnPosXY(v->x_pos, v->y_pos, &tcc, FindTrainCollideEnum);
03605   }
03606 
03607   /* any dead -> no crash */
03608   if (tcc.num == 0) return false;
03609 
03610   SetDParam(0, tcc.num);
03611   AddNewsItem(STR_8868_TRAIN_CRASH_DIE_IN_FIREBALL,
03612     NS_ACCIDENT_VEHICLE,
03613     v->index,
03614     0
03615   );
03616 
03617   ModifyStationRatingAround(v->tile, v->owner, -160, 30);
03618   SndPlayVehicleFx(SND_13_BIG_CRASH, v);
03619   return true;
03620 }
03621 
03622 static Vehicle *CheckVehicleAtSignal(Vehicle *v, void *data)
03623 {
03624   DiagDirection exitdir = *(DiagDirection *)data;
03625 
03626   /* front engine of a train, not inside wormhole or depot, not crashed */
03627   if (v->type == VEH_TRAIN && IsFrontEngine(v) && (v->u.rail.track & TRACK_BIT_MASK) != 0 && !(v->vehstatus & VS_CRASHED)) {
03628     if (v->cur_speed <= 5 && TrainExitDir(v->direction, v->u.rail.track) == exitdir) return v;
03629   }
03630 
03631   return NULL;
03632 }
03633 
03634 static void TrainController(Vehicle *v, Vehicle *nomove, bool update_image)
03635 {
03636   Vehicle *prev;
03637 
03638   /* For every vehicle after and including the given vehicle */
03639   for (prev = v->Previous(); v != nomove; prev = v, v = v->Next()) {
03640     DiagDirection enterdir = DIAGDIR_BEGIN;
03641     bool update_signals_crossing = false; // will we update signals or crossing state?
03642     BeginVehicleMove(v);
03643 
03644     GetNewVehiclePosResult gp = GetNewVehiclePos(v);
03645     if (v->u.rail.track != TRACK_BIT_WORMHOLE) {
03646       /* Not inside tunnel */
03647       if (gp.old_tile == gp.new_tile) {
03648         /* Staying in the old tile */
03649         if (v->u.rail.track == TRACK_BIT_DEPOT) {
03650           /* Inside depot */
03651           gp.x = v->x_pos;
03652           gp.y = v->y_pos;
03653         } else {
03654           /* Not inside depot */
03655 
03656           /* Reverse when we are at the end of the track already, do not move to the new position */
03657           if (IsFrontEngine(v) && !TrainCheckIfLineEnds(v)) return;
03658 
03659           uint32 r = VehicleEnterTile(v, gp.new_tile, gp.x, gp.y);
03660           if (HasBit(r, VETS_CANNOT_ENTER)) {
03661             goto invalid_rail;
03662           }
03663           if (HasBit(r, VETS_ENTERED_STATION)) {
03664             /* The new position is the end of the platform */
03665             TrainEnterStation(v, r >> VETS_STATION_ID_OFFSET);
03666           }
03667         }
03668       } else {
03669         /* A new tile is about to be entered. */
03670 
03671         /* Determine what direction we're entering the new tile from */
03672         Direction dir = GetNewVehicleDirectionByTile(gp.new_tile, gp.old_tile);
03673         enterdir = DirToDiagDir(dir);
03674         assert(IsValidDiagDirection(enterdir));
03675 
03676         /* Get the status of the tracks in the new tile and mask
03677          * away the bits that aren't reachable. */
03678         TrackStatus ts = GetTileTrackStatus(gp.new_tile, TRANSPORT_RAIL, 0, ReverseDiagDir(enterdir));
03679         TrackdirBits reachable_trackdirs = DiagdirReachesTrackdirs(enterdir);
03680 
03681         TrackdirBits trackdirbits = TrackStatusToTrackdirBits(ts) & reachable_trackdirs;
03682         TrackBits red_signals = TrackdirBitsToTrackBits(TrackStatusToRedSignals(ts) & reachable_trackdirs);
03683 
03684         TrackBits bits = TrackdirBitsToTrackBits(trackdirbits);
03685         if (_settings_game.pf.pathfinder_for_trains != VPF_NTP && _settings_game.pf.forbid_90_deg && prev == NULL) {
03686           /* We allow wagons to make 90 deg turns, because forbid_90_deg
03687            * can be switched on halfway a turn */
03688           bits &= ~TrackCrossesTracks(FindFirstTrack(v->u.rail.track));
03689         }
03690 
03691         if (bits == TRACK_BIT_NONE) goto invalid_rail;
03692 
03693         /* Check if the new tile contrains tracks that are compatible
03694          * with the current train, if not, bail out. */
03695         if (!CheckCompatibleRail(v, gp.new_tile)) goto invalid_rail;
03696 
03697         TrackBits chosen_track;
03698         if (prev == NULL) {
03699           /* Currently the locomotive is active. Determine which one of the
03700            * available tracks to choose */
03701           chosen_track = TrackToTrackBits(ChooseTrainTrack(v, gp.new_tile, enterdir, bits, false, NULL, true));
03702           assert(chosen_track & (bits | GetReservedTrackbits(gp.new_tile)));
03703 
03704           /* Check if it's a red signal and that force proceed is not clicked. */
03705           if (red_signals & chosen_track && v->u.rail.force_proceed == 0) {
03706             /* In front of a red signal */
03707             Trackdir i = FindFirstTrackdir(trackdirbits);
03708 
03709             /* Don't handle stuck trains here. */
03710             if (HasBit(v->u.rail.flags, VRF_TRAIN_STUCK)) return;
03711 
03712             if (!HasSignalOnTrackdir(gp.new_tile, ReverseTrackdir(i))) {
03713               v->cur_speed = 0;
03714               v->subspeed = 0;
03715               v->progress = 255 - 100;
03716               if (_settings_game.pf.wait_oneway_signal == 255 || ++v->load_unload_time_rem < _settings_game.pf.wait_oneway_signal * 20) return;
03717             } else if (HasSignalOnTrackdir(gp.new_tile, i)) {
03718               v->cur_speed = 0;
03719               v->subspeed = 0;
03720               v->progress = 255 - 10;
03721               if (_settings_game.pf.wait_twoway_signal == 255 || ++v->load_unload_time_rem < _settings_game.pf.wait_twoway_signal * 73) {
03722                 DiagDirection exitdir = TrackdirToExitdir(i);
03723                 TileIndex o_tile = TileAddByDiagDir(gp.new_tile, exitdir);
03724 
03725                 exitdir = ReverseDiagDir(exitdir);
03726 
03727                 /* check if a train is waiting on the other side */
03728                 if (!HasVehicleOnPos(o_tile, &exitdir, &CheckVehicleAtSignal)) return;
03729               }
03730             }
03731 
03732             /* If we would reverse but are currently in a PBS block and
03733              * reversing of stuck trains is disabled, don't reverse. */
03734             if (_settings_game.pf.wait_for_pbs_path == 255 && UpdateSignalsOnSegment(v->tile, enterdir, v->owner) == SIGSEG_PBS) {
03735               v->load_unload_time_rem = 0;
03736               return;
03737             }
03738             goto reverse_train_direction;
03739           } else {
03740             TryReserveRailTrack(gp.new_tile, TrackBitsToTrack(chosen_track));
03741           }
03742         } else {
03743           static const TrackBits _matching_tracks[8] = {
03744               TRACK_BIT_LEFT  | TRACK_BIT_RIGHT, TRACK_BIT_X,
03745               TRACK_BIT_UPPER | TRACK_BIT_LOWER, TRACK_BIT_Y,
03746               TRACK_BIT_LEFT  | TRACK_BIT_RIGHT, TRACK_BIT_X,
03747               TRACK_BIT_UPPER | TRACK_BIT_LOWER, TRACK_BIT_Y
03748           };
03749 
03750           /* The wagon is active, simply follow the prev vehicle. */
03751           chosen_track = (TrackBits)(byte)(_matching_tracks[GetDirectionToVehicle(prev, gp.x, gp.y)] & bits);
03752         }
03753 
03754         /* Make sure chosen track is a valid track */
03755         assert(
03756             chosen_track == TRACK_BIT_X     || chosen_track == TRACK_BIT_Y ||
03757             chosen_track == TRACK_BIT_UPPER || chosen_track == TRACK_BIT_LOWER ||
03758             chosen_track == TRACK_BIT_LEFT  || chosen_track == TRACK_BIT_RIGHT);
03759 
03760         /* Update XY to reflect the entrance to the new tile, and select the direction to use */
03761         const byte *b = _initial_tile_subcoord[FIND_FIRST_BIT(chosen_track)][enterdir];
03762         gp.x = (gp.x & ~0xF) | b[0];
03763         gp.y = (gp.y & ~0xF) | b[1];
03764         Direction chosen_dir = (Direction)b[2];
03765 
03766         /* Call the landscape function and tell it that the vehicle entered the tile */
03767         uint32 r = VehicleEnterTile(v, gp.new_tile, gp.x, gp.y);
03768         if (HasBit(r, VETS_CANNOT_ENTER)) {
03769           goto invalid_rail;
03770         }
03771 
03772         if (!HasBit(r, VETS_ENTERED_WORMHOLE)) {
03773           Track track = FindFirstTrack(chosen_track);
03774           Trackdir tdir = TrackDirectionToTrackdir(track, chosen_dir);
03775           if (IsFrontEngine(v) && HasPbsSignalOnTrackdir(gp.new_tile, tdir)) {
03776             SetSignalStateByTrackdir(gp.new_tile, tdir, SIGNAL_STATE_RED);
03777             MarkTileDirtyByTile(gp.new_tile);
03778           }
03779 
03780           /* Clear any track reservation when the last vehicle leaves the tile */
03781           if (v->Next() == NULL) ClearPathReservation(v, v->tile, GetVehicleTrackdir(v));
03782 
03783           v->tile = gp.new_tile;
03784 
03785           if (GetTileRailType(gp.new_tile) != GetTileRailType(gp.old_tile)) {
03786             TrainPowerChanged(v->First());
03787           }
03788 
03789           v->u.rail.track = chosen_track;
03790           assert(v->u.rail.track);
03791         }
03792 
03793         /* We need to update signal status, but after the vehicle position hash
03794          * has been updated by AfterSetTrainPos() */
03795         update_signals_crossing = true;
03796 
03797         if (prev == NULL) AffectSpeedByDirChange(v, chosen_dir);
03798 
03799         v->direction = chosen_dir;
03800 
03801         if (IsFrontEngine(v)) {
03802           v->load_unload_time_rem = 0;
03803 
03804           /* If we are approching a crossing that is reserved, play the sound now. */
03805           TileIndex crossing = TrainApproachingCrossingTile(v);
03806           if (crossing != INVALID_TILE && GetCrossingReservation(crossing)) SndPlayTileFx(SND_0E_LEVEL_CROSSING, crossing);
03807 
03808           /* Always try to extend the reservation when entering a tile. */
03809           CheckNextTrainTile(v);
03810         }
03811       }
03812     } else {
03813       /* In a tunnel or on a bridge
03814        * - for tunnels, only the part when the vehicle is not visible (part of enter/exit tile too)
03815        * - for bridges, only the middle part - without the bridge heads */
03816       if (!(v->vehstatus & VS_HIDDEN)) {
03817         v->cur_speed =
03818           min(v->cur_speed, GetBridgeSpec(GetBridgeType(v->tile))->speed);
03819       }
03820 
03821       if (IsTileType(gp.new_tile, MP_TUNNELBRIDGE) && HasBit(VehicleEnterTile(v, gp.new_tile, gp.x, gp.y), VETS_ENTERED_WORMHOLE)) {
03822         /* Perform look-ahead on tunnel exit. */
03823         if (IsFrontEngine(v)) {
03824           TryReserveRailTrack(gp.new_tile, DiagDirToDiagTrack(GetTunnelBridgeDirection(gp.new_tile)));
03825           CheckNextTrainTile(v);
03826         }
03827       } else {
03828         v->x_pos = gp.x;
03829         v->y_pos = gp.y;
03830         VehiclePositionChanged(v);
03831         if (!(v->vehstatus & VS_HIDDEN)) EndVehicleMove(v);
03832         continue;
03833       }
03834     }
03835 
03836     /* update image of train, as well as delta XY */
03837     v->UpdateDeltaXY(v->direction);
03838     if (update_image) v->cur_image = v->GetImage(v->direction);
03839 
03840     v->x_pos = gp.x;
03841     v->y_pos = gp.y;
03842 
03843     /* update the Z position of the vehicle */
03844     byte old_z = AfterSetTrainPos(v, (gp.new_tile != gp.old_tile));
03845 
03846     if (prev == NULL) {
03847       /* This is the first vehicle in the train */
03848       AffectSpeedByZChange(v, old_z);
03849     }
03850 
03851     if (update_signals_crossing) {
03852       if (IsFrontEngine(v)) {
03853         if (TrainMovedChangeSignals(gp.new_tile, enterdir)) {
03854           /* We are entering a block with PBS signals right now, but
03855            * not through a PBS signal. This means we don't have a
03856            * reservation right now. As a conventional signal will only
03857            * ever be green if no other train is in the block, getting
03858            * a path should always be possible. If the player built
03859            * such a strange network that it is not possible, the train
03860            * will be marked as stuck and the player has to deal with
03861            * the problem. */
03862           if ((!HasReservedTracks(gp.new_tile, v->u.rail.track) &&
03863               !TryReserveRailTrack(gp.new_tile, FindFirstTrack(v->u.rail.track))) ||
03864               !TryPathReserve(v)) {
03865             MarkTrainAsStuck(v);
03866           }
03867         }
03868       }
03869 
03870       /* Signals can only change when the first
03871        * (above) or the last vehicle moves. */
03872       if (v->Next() == NULL) {
03873         TrainMovedChangeSignals(gp.old_tile, ReverseDiagDir(enterdir));
03874         if (IsLevelCrossingTile(gp.old_tile)) UpdateLevelCrossing(gp.old_tile);
03875       }
03876     }
03877 
03878     /* Do not check on every tick to save some computing time. */
03879     if (IsFrontEngine(v) && v->tick_counter % _settings_game.pf.path_backoff_interval == 0) CheckNextTrainTile(v);
03880   }
03881   return;
03882 
03883 invalid_rail:
03884   /* We've reached end of line?? */
03885   if (prev != NULL) error("Disconnecting train");
03886 
03887 reverse_train_direction:
03888   v->load_unload_time_rem = 0;
03889   v->cur_speed = 0;
03890   v->subspeed = 0;
03891   ReverseTrainDirection(v);
03892 }
03893 
03899 static Vehicle *CollectTrackbitsFromCrashedVehiclesEnum(Vehicle *v, void *data)
03900 {
03901   TrackBits *trackbits = (TrackBits *)data;
03902 
03903   if (v->type == VEH_TRAIN && (v->vehstatus & VS_CRASHED) != 0) {
03904     if ((v->u.rail.track & TRACK_BIT_WORMHOLE) == TRACK_BIT_WORMHOLE) {
03905       /* Vehicle is inside a wormhole, v->u.rail.track contains no useful value then. */
03906       *trackbits |= DiagDirToDiagTrackBits(GetTunnelBridgeDirection(v->tile));
03907     } else {
03908       *trackbits |= v->u.rail.track;
03909     }
03910   }
03911 
03912   return NULL;
03913 }
03914 
03922 static void DeleteLastWagon(Vehicle *v)
03923 {
03924   Vehicle *first = v->First();
03925 
03926   /* Go to the last wagon and delete the link pointing there
03927    * *u is then the one-before-last wagon, and *v the last
03928    * one which will physicially be removed */
03929   Vehicle *u = v;
03930   for (; v->Next() != NULL; v = v->Next()) u = v;
03931   u->SetNext(NULL);
03932 
03933   if (first != v) {
03934     /* Recalculate cached train properties */
03935     TrainConsistChanged(first, false);
03936     /* Update the depot window if the first vehicle is in depot -
03937      * if v == first, then it is updated in PreDestructor() */
03938     if (first->u.rail.track == TRACK_BIT_DEPOT) {
03939       InvalidateWindow(WC_VEHICLE_DEPOT, first->tile);
03940     }
03941   }
03942 
03943   /* 'v' shouldn't be accessed after it has been deleted */
03944   TrackBits trackbits = v->u.rail.track;
03945   TileIndex tile = v->tile;
03946   Owner owner = v->owner;
03947 
03948   delete v;
03949   v = NULL; // make sure nobody will try to read 'v' anymore
03950 
03951   if ((trackbits & TRACK_BIT_WORMHOLE) == TRACK_BIT_WORMHOLE) {
03952     /* Vehicle is inside a wormhole, v->u.rail.track contains no useful value then. */
03953     trackbits |= DiagDirToDiagTrackBits(GetTunnelBridgeDirection(tile));
03954   }
03955 
03956   Track track = TrackBitsToTrack(trackbits);
03957   if (HasReservedTracks(tile, trackbits)) {
03958     UnreserveRailTrack(tile, track);
03959 
03960     /* If there are still crashed vehicles on the tile, give the track reservation to them */
03961     TrackBits remaining_trackbits = TRACK_BIT_NONE;
03962     FindVehicleOnPos(tile, &remaining_trackbits, CollectTrackbitsFromCrashedVehiclesEnum);
03963 
03964     /* It is important that these two are the first in the loop, as reservation cannot deal with every trackbit combination */
03965     assert(TRACK_BEGIN == TRACK_X && TRACK_Y == TRACK_BEGIN + 1);
03966     for (Track t = TRACK_BEGIN; t < TRACK_END; t++) {
03967       if (HasBit(remaining_trackbits, t)) {
03968         TryReserveRailTrack(tile, t);
03969       }
03970     }
03971   }
03972 
03973   /* check if the wagon was on a road/rail-crossing */
03974   if (IsLevelCrossingTile(tile)) UpdateLevelCrossing(tile);
03975 
03976   /* Update signals */
03977   if (IsTileType(tile, MP_TUNNELBRIDGE) || IsRailDepotTile(tile)) {
03978     UpdateSignalsOnSegment(tile, INVALID_DIAGDIR, owner);
03979   } else {
03980     SetSignalsOnBothDir(tile, track, owner);
03981   }
03982 }
03983 
03984 static void ChangeTrainDirRandomly(Vehicle *v)
03985 {
03986   static const DirDiff delta[] = {
03987     DIRDIFF_45LEFT, DIRDIFF_SAME, DIRDIFF_SAME, DIRDIFF_45RIGHT
03988   };
03989 
03990   do {
03991     /* We don't need to twist around vehicles if they're not visible */
03992     if (!(v->vehstatus & VS_HIDDEN)) {
03993       v->direction = ChangeDir(v->direction, delta[GB(Random(), 0, 2)]);
03994       BeginVehicleMove(v);
03995       v->UpdateDeltaXY(v->direction);
03996       v->cur_image = v->GetImage(v->direction);
03997       /* Refrain from updating the z position of the vehicle when on
03998        * a bridge, because AfterSetTrainPos will put the vehicle under
03999        * the bridge in that case */
04000       if (v->u.rail.track != TRACK_BIT_WORMHOLE) AfterSetTrainPos(v, false);
04001     }
04002   } while ((v = v->Next()) != NULL);
04003 }
04004 
04005 static void HandleCrashedTrain(Vehicle *v)
04006 {
04007   int state = ++v->u.rail.crash_anim_pos;
04008 
04009   if (state == 4 && !(v->vehstatus & VS_HIDDEN)) {
04010     CreateEffectVehicleRel(v, 4, 4, 8, EV_EXPLOSION_LARGE);
04011   }
04012 
04013   uint32 r;
04014   if (state <= 200 && Chance16R(1, 7, r)) {
04015     int index = (r * 10 >> 16);
04016 
04017     Vehicle *u = v;
04018     do {
04019       if (--index < 0) {
04020         r = Random();
04021 
04022         CreateEffectVehicleRel(u,
04023           GB(r,  8, 3) + 2,
04024           GB(r, 16, 3) + 2,
04025           GB(r,  0, 3) + 5,
04026           EV_EXPLOSION_SMALL);
04027         break;
04028       }
04029     } while ((u = u->Next()) != NULL);
04030   }
04031 
04032   if (state <= 240 && !(v->tick_counter & 3)) ChangeTrainDirRandomly(v);
04033 
04034   if (state >= 4440 && !(v->tick_counter & 0x1F)) {
04035     DeleteLastWagon(v);
04036     InvalidateWindow(WC_REPLACE_VEHICLE, (v->group_id << 16) | VEH_TRAIN);
04037   }
04038 }
04039 
04040 static void HandleBrokenTrain(Vehicle *v)
04041 {
04042   if (v->breakdown_ctr != 1) {
04043     v->breakdown_ctr = 1;
04044     v->cur_speed = 0;
04045 
04046     if (v->breakdowns_since_last_service != 255)
04047       v->breakdowns_since_last_service++;
04048 
04049     InvalidateWindow(WC_VEHICLE_VIEW, v->index);
04050     InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
04051 
04052     if (!PlayVehicleSound(v, VSE_BREAKDOWN)) {
04053       SndPlayVehicleFx((_settings_game.game_creation.landscape != LT_TOYLAND) ?
04054         SND_10_TRAIN_BREAKDOWN : SND_3A_COMEDY_BREAKDOWN_2, v);
04055     }
04056 
04057     if (!(v->vehstatus & VS_HIDDEN)) {
04058       Vehicle *u = CreateEffectVehicleRel(v, 4, 4, 5, EV_BREAKDOWN_SMOKE);
04059       if (u != NULL) u->u.effect.animation_state = v->breakdown_delay * 2;
04060     }
04061   }
04062 
04063   if (!(v->tick_counter & 3)) {
04064     if (!--v->breakdown_delay) {
04065       v->breakdown_ctr = 0;
04066       InvalidateWindow(WC_VEHICLE_VIEW, v->index);
04067     }
04068   }
04069 }
04070 
04072 static const uint16 _breakdown_speeds[16] = {
04073   225, 210, 195, 180, 165, 150, 135, 120, 105, 90, 75, 60, 45, 30, 15, 15
04074 };
04075 
04076 
04084 static bool TrainApproachingLineEnd(Vehicle *v, bool signal)
04085 {
04086   /* Calc position within the current tile */
04087   uint x = v->x_pos & 0xF;
04088   uint y = v->y_pos & 0xF;
04089 
04090   /* for diagonal directions, 'x' will be 0..15 -
04091    * for other directions, it will be 1, 3, 5, ..., 15 */
04092   switch (v->direction) {
04093     case DIR_N : x = ~x + ~y + 25; break;
04094     case DIR_NW: x = y;            /* FALLTHROUGH */
04095     case DIR_NE: x = ~x + 16;      break;
04096     case DIR_E : x = ~x + y + 9;   break;
04097     case DIR_SE: x = y;            break;
04098     case DIR_S : x = x + y - 7;    break;
04099     case DIR_W : x = ~y + x + 9;   break;
04100     default: break;
04101   }
04102 
04103   /* do not reverse when approaching red signal */
04104   if (!signal && x + (v->u.rail.cached_veh_length + 1) / 2 >= TILE_SIZE) {
04105     /* we are too near the tile end, reverse now */
04106     v->cur_speed = 0;
04107     ReverseTrainDirection(v);
04108     return false;
04109   }
04110 
04111   /* slow down */
04112   v->vehstatus |= VS_TRAIN_SLOWING;
04113   uint16 break_speed = _breakdown_speeds[x & 0xF];
04114   if (break_speed < v->cur_speed) v->cur_speed = break_speed;
04115 
04116   return true;
04117 }
04118 
04119 
04125 static bool TrainCanLeaveTile(const Vehicle *v)
04126 {
04127   /* Exit if inside a tunnel/bridge or a depot */
04128   if (v->u.rail.track == TRACK_BIT_WORMHOLE || v->u.rail.track == TRACK_BIT_DEPOT) return false;
04129 
04130   TileIndex tile = v->tile;
04131 
04132   /* entering a tunnel/bridge? */
04133   if (IsTileType(tile, MP_TUNNELBRIDGE)) {
04134     DiagDirection dir = GetTunnelBridgeDirection(tile);
04135     if (DiagDirToDir(dir) == v->direction) return false;
04136   }
04137 
04138   /* entering a depot? */
04139   if (IsRailDepotTile(tile)) {
04140     DiagDirection dir = ReverseDiagDir(GetRailDepotDirection(tile));
04141     if (DiagDirToDir(dir) == v->direction) return false;
04142   }
04143 
04144   return true;
04145 }
04146 
04147 
04155 static TileIndex TrainApproachingCrossingTile(const Vehicle *v)
04156 {
04157   assert(IsFrontEngine(v));
04158   assert(!(v->vehstatus & VS_CRASHED));
04159 
04160   if (!TrainCanLeaveTile(v)) return INVALID_TILE;
04161 
04162   DiagDirection dir = TrainExitDir(v->direction, v->u.rail.track);
04163   TileIndex tile = v->tile + TileOffsByDiagDir(dir);
04164 
04165   /* not a crossing || wrong axis || unusable rail (wrong type or owner) */
04166   if (!IsLevelCrossingTile(tile) || DiagDirToAxis(dir) == GetCrossingRoadAxis(tile) ||
04167       !CheckCompatibleRail(v, tile)) {
04168     return INVALID_TILE;
04169   }
04170 
04171   return tile;
04172 }
04173 
04174 
04181 static bool TrainCheckIfLineEnds(Vehicle *v)
04182 {
04183   /* First, handle broken down train */
04184 
04185   int t = v->breakdown_ctr;
04186   if (t > 1) {
04187     v->vehstatus |= VS_TRAIN_SLOWING;
04188 
04189     uint16 break_speed = _breakdown_speeds[GB(~t, 4, 4)];
04190     if (break_speed < v->cur_speed) v->cur_speed = break_speed;
04191   } else {
04192     v->vehstatus &= ~VS_TRAIN_SLOWING;
04193   }
04194 
04195   if (!TrainCanLeaveTile(v)) return true;
04196 
04197   /* Determine the non-diagonal direction in which we will exit this tile */
04198   DiagDirection dir = TrainExitDir(v->direction, v->u.rail.track);
04199   /* Calculate next tile */
04200   TileIndex tile = v->tile + TileOffsByDiagDir(dir);
04201 
04202   /* Determine the track status on the next tile */
04203   TrackStatus ts = GetTileTrackStatus(tile, TRANSPORT_RAIL, 0, ReverseDiagDir(dir));
04204   TrackdirBits reachable_trackdirs = DiagdirReachesTrackdirs(dir);
04205 
04206   TrackdirBits trackdirbits = TrackStatusToTrackdirBits(ts) & reachable_trackdirs;
04207   TrackdirBits red_signals = TrackStatusToRedSignals(ts) & reachable_trackdirs;
04208 
04209   /* We are sure the train is not entering a depot, it is detected above */
04210 
04211   /* mask unreachable track bits if we are forbidden to do 90deg turns */
04212   TrackBits bits = TrackdirBitsToTrackBits(trackdirbits);
04213   if (_settings_game.pf.pathfinder_for_trains != VPF_NTP && _settings_game.pf.forbid_90_deg) {
04214     bits &= ~TrackCrossesTracks(FindFirstTrack(v->u.rail.track));
04215   }
04216 
04217   /* no suitable trackbits at all || unusable rail (wrong type or owner) */
04218   if (bits == TRACK_BIT_NONE || !CheckCompatibleRail(v, tile)) {
04219     return TrainApproachingLineEnd(v, false);
04220   }
04221 
04222   /* approaching red signal */
04223   if ((trackdirbits & red_signals) != 0) return TrainApproachingLineEnd(v, true);
04224 
04225   /* approaching a rail/road crossing? then make it red */
04226   if (IsLevelCrossingTile(tile)) MaybeBarCrossingWithSound(tile);
04227 
04228   return true;
04229 }
04230 
04231 
04232 static void TrainLocoHandler(Vehicle *v, bool mode)
04233 {
04234   /* train has crashed? */
04235   if (v->vehstatus & VS_CRASHED) {
04236     if (!mode) HandleCrashedTrain(v);
04237     return;
04238   }
04239 
04240   if (v->u.rail.force_proceed != 0) {
04241     v->u.rail.force_proceed--;
04242     ClrBit(v->u.rail.flags, VRF_TRAIN_STUCK);
04243     InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
04244   }
04245 
04246   /* train is broken down? */
04247   if (v->breakdown_ctr != 0) {
04248     if (v->breakdown_ctr <= 2) {
04249       HandleBrokenTrain(v);
04250       return;
04251     }
04252     if (!v->current_order.IsType(OT_LOADING)) v->breakdown_ctr--;
04253   }
04254 
04255   if (HasBit(v->u.rail.flags, VRF_REVERSING) && v->cur_speed == 0) {
04256     ReverseTrainDirection(v);
04257   }
04258 
04259   /* exit if train is stopped */
04260   if (v->vehstatus & VS_STOPPED && v->cur_speed == 0) return;
04261 
04262   bool valid_order = v->current_order.IsValid() && v->current_order.GetType() != OT_CONDITIONAL;
04263   if (ProcessOrders(v) && CheckReverseTrain(v)) {
04264     v->load_unload_time_rem = 0;
04265     v->cur_speed = 0;
04266     v->subspeed = 0;
04267     ReverseTrainDirection(v);
04268     return;
04269   }
04270 
04271   v->HandleLoading(mode);
04272 
04273   if (v->current_order.IsType(OT_LOADING)) return;
04274 
04275   if (CheckTrainStayInDepot(v)) return;
04276 
04277   if (!mode) HandleLocomotiveSmokeCloud(v);
04278 
04279   /* We had no order but have an order now, do look ahead. */
04280   if (!valid_order && v->current_order.IsValid()) {
04281     CheckNextTrainTile(v);
04282   }
04283 
04284   /* Handle stuck trains. */
04285   if (!mode && HasBit(v->u.rail.flags, VRF_TRAIN_STUCK)) {
04286     ++v->load_unload_time_rem;
04287 
04288     /* Should we try reversing this tick if still stuck? */
04289     bool turn_around = v->load_unload_time_rem % (_settings_game.pf.wait_for_pbs_path * DAY_TICKS) == 0 && _settings_game.pf.wait_for_pbs_path < 255;
04290 
04291     if (!turn_around && v->load_unload_time_rem % _settings_game.pf.path_backoff_interval != 0 && v->u.rail.force_proceed == 0) return;
04292     if (!TryPathReserve(v)) {
04293       /* Still stuck. */
04294       if (turn_around) ReverseTrainDirection(v);
04295 
04296       if (HasBit(v->u.rail.flags, VRF_TRAIN_STUCK) && v->load_unload_time_rem > 2 * _settings_game.pf.wait_for_pbs_path * DAY_TICKS) {
04297         /* Show message to player. */
04298         if (_settings_client.gui.lost_train_warn && v->owner == _local_company) {
04299           SetDParam(0, v->index);
04300           AddNewsItem(
04301             STR_TRAIN_IS_STUCK,
04302             NS_ADVICE,
04303             v->index,
04304             0);
04305         }
04306         v->load_unload_time_rem = 0;
04307       }
04308       /* Exit if force proceed not pressed, else reset stuck flag anyway. */
04309       if (v->u.rail.force_proceed == 0) return;
04310       ClrBit(v->u.rail.flags, VRF_TRAIN_STUCK);
04311       v->load_unload_time_rem = 0;
04312       InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
04313     }
04314   }
04315 
04316   if (v->current_order.IsType(OT_LEAVESTATION)) {
04317     v->current_order.Free();
04318     InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
04319     return;
04320   }
04321 
04322   int j = UpdateTrainSpeed(v);
04323 
04324   /* we need to invalidate the widget if we are stopping from 'Stopping 0 km/h' to 'Stopped' */
04325   if (v->cur_speed == 0 && v->u.rail.last_speed == 0 && v->vehstatus & VS_STOPPED) {
04326     InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
04327   }
04328 
04329   int adv_spd = (v->direction & 1) ? 192 : 256;
04330   if (j < adv_spd) {
04331     /* if the vehicle has speed 0, update the last_speed field. */
04332     if (v->cur_speed == 0) SetLastSpeed(v, v->cur_speed);
04333   } else {
04334     TrainCheckIfLineEnds(v);
04335     /* Loop until the train has finished moving. */
04336     do {
04337       j -= adv_spd;
04338       TrainController(v, NULL, true);
04339       /* Don't continue to move if the train crashed. */
04340       if (CheckTrainCollision(v)) break;
04341       /* 192 spd used for going straight, 256 for going diagonally. */
04342       adv_spd = (v->direction & 1) ? 192 : 256;
04343     } while (j >= adv_spd);
04344     SetLastSpeed(v, v->cur_speed);
04345   }
04346 
04347   if (v->progress == 0) v->progress = j; // Save unused spd for next time, if TrainController didn't set progress
04348 }
04349 
04350 
04351 
04352 Money Train::GetRunningCost() const
04353 {
04354   Money cost = 0;
04355   const Vehicle *v = this;
04356 
04357   do {
04358     const RailVehicleInfo *rvi = RailVehInfo(v->engine_type);
04359 
04360     byte cost_factor = GetVehicleProperty(v, 0x0D, rvi->running_cost);
04361     if (cost_factor == 0) continue;
04362 
04363     /* Halve running cost for multiheaded parts */
04364     if (IsMultiheaded(v)) cost_factor /= 2;
04365 
04366     cost += cost_factor * GetPriceByIndex(rvi->running_cost_class);
04367   } while ((v = GetNextVehicle(v)) != NULL);
04368 
04369   return cost;
04370 }
04371 
04372 
04373 void Train::Tick()
04374 {
04375   if (_age_cargo_skip_counter == 0) this->cargo.AgeCargo();
04376 
04377   this->tick_counter++;
04378 
04379   if (IsFrontEngine(this)) {
04380     if (!(this->vehstatus & VS_STOPPED)) this->running_ticks++;
04381     this->current_order_time++;
04382 
04383     TrainLocoHandler(this, false);
04384 
04385     /* make sure vehicle wasn't deleted. */
04386     if (this->type == VEH_TRAIN && IsFrontEngine(this))
04387       TrainLocoHandler(this, true);
04388   } else if (IsFreeWagon(this) && HASBITS(this->vehstatus, VS_CRASHED)) {
04389     /* Delete flooded standalone wagon chain */
04390     if (++this->u.rail.crash_anim_pos >= 4400) delete this;
04391   }
04392 }
04393 
04394 static void CheckIfTrainNeedsService(Vehicle *v)
04395 {
04396   static const uint MAX_ACCEPTABLE_DEPOT_DIST = 16;
04397 
04398   if (_settings_game.vehicle.servint_trains == 0 || !v->NeedsAutomaticServicing()) return;
04399   if (v->IsInDepot()) {
04400     VehicleServiceInDepot(v);
04401     return;
04402   }
04403 
04404   TrainFindDepotData tfdd = FindClosestTrainDepot(v, MAX_ACCEPTABLE_DEPOT_DIST);
04405   /* Only go to the depot if it is not too far out of our way. */
04406   if (tfdd.best_length == UINT_MAX || tfdd.best_length > MAX_ACCEPTABLE_DEPOT_DIST) {
04407     if (v->current_order.IsType(OT_GOTO_DEPOT)) {
04408       /* If we were already heading for a depot but it has
04409        * suddenly moved farther away, we continue our normal
04410        * schedule? */
04411       v->current_order.MakeDummy();
04412       InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
04413     }
04414     return;
04415   }
04416 
04417   const Depot *depot = GetDepotByTile(tfdd.tile);
04418 
04419   if (v->current_order.IsType(OT_GOTO_DEPOT) &&
04420       v->current_order.GetDestination() != depot->index &&
04421       !Chance16(3, 16)) {
04422     return;
04423   }
04424 
04425   v->current_order.MakeGoToDepot(depot->index, ODTFB_SERVICE);
04426   v->dest_tile = tfdd.tile;
04427   InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
04428 }
04429 
04430 void Train::OnNewDay()
04431 {
04432   if ((++this->day_counter & 7) == 0) DecreaseVehicleValue(this);
04433 
04434   if (IsFrontEngine(this)) {
04435     CheckVehicleBreakdown(this);
04436     AgeVehicle(this);
04437 
04438     CheckIfTrainNeedsService(this);
04439 
04440     CheckOrders(this);
04441 
04442     /* update destination */
04443     if (this->current_order.IsType(OT_GOTO_STATION)) {
04444       TileIndex tile = GetStation(this->current_order.GetDestination())->train_tile;
04445       if (tile != INVALID_TILE) this->dest_tile = tile;
04446     }
04447 
04448     if (this->running_ticks != 0) {
04449       /* running costs */
04450       CommandCost cost(EXPENSES_TRAIN_RUN, this->GetRunningCost() * this->running_ticks / (DAYS_IN_YEAR  * DAY_TICKS));
04451 
04452       this->profit_this_year -= cost.GetCost();
04453       this->running_ticks = 0;
04454 
04455       SubtractMoneyFromCompanyFract(this->owner, cost);
04456 
04457       InvalidateWindow(WC_VEHICLE_DETAILS, this->index);
04458       InvalidateWindowClasses(WC_TRAINS_LIST);
04459     }
04460   } else if (IsTrainEngine(this)) {
04461     /* Also age engines that aren't front engines */
04462     AgeVehicle(this);
04463   }
04464 }
04465 
04466 void InitializeTrains()
04467 {
04468   _age_cargo_skip_counter = 1;
04469 }

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