train_cmd.cpp

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00001 /* $Id: train_cmd.cpp 16482 2009-05-31 12:22:53Z rubidium $ */
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);
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     ShowNewGrfVehicleError(u->engine_type, STR_NEWGRF_BROKEN, STR_NEWGRF_BROKEN_VEHICLE_LENGTH, GBUG_VEH_LENGTH, true);
00182   }
00183 }
00184 
00186 void CheckTrainsLengths()
00187 {
00188   const Vehicle *v;
00189 
00190   FOR_ALL_VEHICLES(v) {
00191     if (v->type == VEH_TRAIN && v->First() == v && !(v->vehstatus & VS_CRASHED)) {
00192       for (const Vehicle *u = v, *w = v->Next(); w != NULL; u = w, w = w->Next()) {
00193         if (u->u.rail.track != TRACK_BIT_DEPOT) {
00194           if ((w->u.rail.track != TRACK_BIT_DEPOT &&
00195               max(abs(u->x_pos - w->x_pos), abs(u->y_pos - w->y_pos)) != u->u.rail.cached_veh_length) ||
00196               (w->u.rail.track == TRACK_BIT_DEPOT && TicksToLeaveDepot(u) <= 0)) {
00197             SetDParam(0, v->index);
00198             SetDParam(1, v->owner);
00199             ShowErrorMessage(INVALID_STRING_ID, STR_BROKEN_VEHICLE_LENGTH, 0, 0);
00200 
00201             if (!_networking) _pause_game = -1;
00202           }
00203         }
00204       }
00205     }
00206   }
00207 }
00208 
00216 void TrainConsistChanged(Vehicle *v, bool same_length)
00217 {
00218   uint16 max_speed = UINT16_MAX;
00219 
00220   assert(v->type == VEH_TRAIN);
00221   assert(IsFrontEngine(v) || IsFreeWagon(v));
00222 
00223   const RailVehicleInfo *rvi_v = RailVehInfo(v->engine_type);
00224   EngineID first_engine = IsFrontEngine(v) ? v->engine_type : INVALID_ENGINE;
00225   v->u.rail.cached_total_length = 0;
00226   v->u.rail.compatible_railtypes = RAILTYPES_NONE;
00227 
00228   bool train_can_tilt = true;
00229 
00230   for (Vehicle *u = v; u != NULL; u = u->Next()) {
00231     const RailVehicleInfo *rvi_u = RailVehInfo(u->engine_type);
00232 
00233     /* Check the v->first cache. */
00234     assert(u->First() == v);
00235 
00236     /* update the 'first engine' */
00237     u->u.rail.first_engine = v == u ? INVALID_ENGINE : first_engine;
00238     u->u.rail.railtype = rvi_u->railtype;
00239 
00240     if (IsTrainEngine(u)) first_engine = u->engine_type;
00241 
00242     /* Set user defined data to its default value */
00243     u->u.rail.user_def_data = rvi_u->user_def_data;
00244     v->InvalidateNewGRFCache();
00245     u->InvalidateNewGRFCache();
00246   }
00247 
00248   for (Vehicle *u = v; u != NULL; u = u->Next()) {
00249     /* Update user defined data (must be done before other properties) */
00250     u->u.rail.user_def_data = GetVehicleProperty(u, 0x25, u->u.rail.user_def_data);
00251     v->InvalidateNewGRFCache();
00252     u->InvalidateNewGRFCache();
00253   }
00254 
00255   for (Vehicle *u = v; u != NULL; u = u->Next()) {
00256     const Engine *e_u = GetEngine(u->engine_type);
00257     const RailVehicleInfo *rvi_u = &e_u->u.rail;
00258 
00259     if (!HasBit(EngInfo(u->engine_type)->misc_flags, EF_RAIL_TILTS)) train_can_tilt = false;
00260 
00261     /* Cache wagon override sprite group. NULL is returned if there is none */
00262     u->u.rail.cached_override = GetWagonOverrideSpriteSet(u->engine_type, u->cargo_type, u->u.rail.first_engine);
00263 
00264     /* Reset colour map */
00265     u->colourmap = PAL_NONE;
00266 
00267     if (rvi_u->visual_effect != 0) {
00268       u->u.rail.cached_vis_effect = rvi_u->visual_effect;
00269     } else {
00270       if (IsTrainWagon(u) || IsArticulatedPart(u)) {
00271         /* Wagons and articulated parts have no effect by default */
00272         u->u.rail.cached_vis_effect = 0x40;
00273       } else if (rvi_u->engclass == 0) {
00274         /* Steam is offset by -4 units */
00275         u->u.rail.cached_vis_effect = 4;
00276       } else {
00277         /* Diesel fumes and sparks come from the centre */
00278         u->u.rail.cached_vis_effect = 8;
00279       }
00280     }
00281 
00282     /* Check powered wagon / visual effect callback */
00283     if (HasBit(EngInfo(u->engine_type)->callbackmask, CBM_TRAIN_WAGON_POWER)) {
00284       uint16 callback = GetVehicleCallback(CBID_TRAIN_WAGON_POWER, 0, 0, u->engine_type, u);
00285 
00286       if (callback != CALLBACK_FAILED) u->u.rail.cached_vis_effect = GB(callback, 0, 8);
00287     }
00288 
00289     if (rvi_v->pow_wag_power != 0 && rvi_u->railveh_type == RAILVEH_WAGON &&
00290       UsesWagonOverride(u) && !HasBit(u->u.rail.cached_vis_effect, 7)) {
00291       /* wagon is powered */
00292       SetBit(u->u.rail.flags, VRF_POWEREDWAGON); // cache 'powered' status
00293     } else {
00294       ClrBit(u->u.rail.flags, VRF_POWEREDWAGON);
00295     }
00296 
00297     if (!IsArticulatedPart(u)) {
00298       /* Do not count powered wagons for the compatible railtypes, as wagons always
00299          have railtype normal */
00300       if (rvi_u->power > 0) {
00301         v->u.rail.compatible_railtypes |= GetRailTypeInfo(u->u.rail.railtype)->powered_railtypes;
00302       }
00303 
00304       /* Some electric engines can be allowed to run on normal rail. It happens to all
00305        * existing electric engines when elrails are disabled and then re-enabled */
00306       if (HasBit(u->u.rail.flags, VRF_EL_ENGINE_ALLOWED_NORMAL_RAIL)) {
00307         u->u.rail.railtype = RAILTYPE_RAIL;
00308         u->u.rail.compatible_railtypes |= RAILTYPES_RAIL;
00309       }
00310 
00311       /* max speed is the minimum of the speed limits of all vehicles in the consist */
00312       if ((rvi_u->railveh_type != RAILVEH_WAGON || _settings_game.vehicle.wagon_speed_limits) && !UsesWagonOverride(u)) {
00313         uint16 speed = GetVehicleProperty(u, 0x09, rvi_u->max_speed);
00314         if (speed != 0) max_speed = min(speed, max_speed);
00315       }
00316     }
00317 
00318     if (e_u->CanCarryCargo() && u->cargo_type == e_u->GetDefaultCargoType() && u->cargo_subtype == 0) {
00319       /* Set cargo capacity if we've not been refitted */
00320       u->cargo_cap = GetVehicleProperty(u, 0x14, rvi_u->capacity);
00321     }
00322 
00323     /* check the vehicle length (callback) */
00324     uint16 veh_len = CALLBACK_FAILED;
00325     if (HasBit(EngInfo(u->engine_type)->callbackmask, CBM_VEHICLE_LENGTH)) {
00326       veh_len = GetVehicleCallback(CBID_VEHICLE_LENGTH, 0, 0, u->engine_type, u);
00327     }
00328     if (veh_len == CALLBACK_FAILED) veh_len = rvi_u->shorten_factor;
00329     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
00330 
00331     /* verify length hasn't changed */
00332     if (same_length && veh_len != u->u.rail.cached_veh_length) RailVehicleLengthChanged(u);
00333 
00334     /* update vehicle length? */
00335     if (!same_length) u->u.rail.cached_veh_length = veh_len;
00336 
00337     v->u.rail.cached_total_length += u->u.rail.cached_veh_length;
00338     v->InvalidateNewGRFCache();
00339     u->InvalidateNewGRFCache();
00340   }
00341 
00342   /* store consist weight/max speed in cache */
00343   v->u.rail.cached_max_speed = max_speed;
00344   v->u.rail.cached_tilt = train_can_tilt;
00345 
00346   /* 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) */
00347   TrainCargoChanged(v);
00348 
00349   if (IsFrontEngine(v)) {
00350     UpdateTrainAcceleration(v);
00351     InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
00352   }
00353 }
00354 
00355 enum AccelType {
00356   AM_ACCEL,
00357   AM_BRAKE
00358 };
00359 
00361 static int GetTrainAcceleration(Vehicle *v, bool mode)
00362 {
00363   static const int absolute_max_speed = UINT16_MAX;
00364   int max_speed = absolute_max_speed;
00365   int speed = v->cur_speed * 10 / 16; // km-ish/h -> mp/h
00366   int curvecount[2] = {0, 0};
00367 
00368   /* first find the curve speed limit */
00369   int numcurve = 0;
00370   int sum = 0;
00371   int pos = 0;
00372   int lastpos = -1;
00373   for (const Vehicle *u = v; u->Next() != NULL; u = u->Next(), pos++) {
00374     Direction this_dir = u->direction;
00375     Direction next_dir = u->Next()->direction;
00376 
00377     DirDiff dirdiff = DirDifference(this_dir, next_dir);
00378     if (dirdiff == DIRDIFF_SAME) continue;
00379 
00380     if (dirdiff == DIRDIFF_45LEFT) curvecount[0]++;
00381     if (dirdiff == DIRDIFF_45RIGHT) curvecount[1]++;
00382     if (dirdiff == DIRDIFF_45LEFT || dirdiff == DIRDIFF_45RIGHT) {
00383       if (lastpos != -1) {
00384         numcurve++;
00385         sum += pos - lastpos;
00386         if (pos - lastpos == 1) {
00387           max_speed = 88;
00388         }
00389       }
00390       lastpos = pos;
00391     }
00392 
00393     /* if we have a 90 degree turn, fix the speed limit to 60 */
00394     if (dirdiff == DIRDIFF_90LEFT || dirdiff == DIRDIFF_90RIGHT) {
00395       max_speed = 61;
00396     }
00397   }
00398 
00399   if ((curvecount[0] != 0 || curvecount[1] != 0) && max_speed > 88) {
00400     int total = curvecount[0] + curvecount[1];
00401 
00402     if (curvecount[0] == 1 && curvecount[1] == 1) {
00403       max_speed = absolute_max_speed;
00404     } else if (total > 1) {
00405       if (numcurve > 0) sum /= numcurve;
00406       max_speed = 232 - (13 - Clamp(sum, 1, 12)) * (13 - Clamp(sum, 1, 12));
00407     }
00408   }
00409 
00410   if (max_speed != absolute_max_speed) {
00411     /* Apply the engine's rail type curve speed advantage, if it slowed by curves */
00412     const RailtypeInfo *rti = GetRailTypeInfo(v->u.rail.railtype);
00413     max_speed += (max_speed / 2) * rti->curve_speed;
00414 
00415     if (v->u.rail.cached_tilt) {
00416       /* Apply max_speed bonus of 20% for a tilting train */
00417       max_speed += max_speed / 5;
00418     }
00419   }
00420 
00421   if (IsTileType(v->tile, MP_STATION) && IsFrontEngine(v)) {
00422     if (v->current_order.ShouldStopAtStation(v, GetStationIndex(v->tile))) {
00423       int station_length = GetStationByTile(v->tile)->GetPlatformLength(v->tile, DirToDiagDir(v->direction));
00424 
00425       int st_max_speed = 120;
00426 
00427       int delta_v = v->cur_speed / (station_length + 1);
00428       if (v->max_speed > (v->cur_speed - delta_v)) {
00429         st_max_speed = v->cur_speed - (delta_v / 10);
00430       }
00431 
00432       st_max_speed = max(st_max_speed, 25 * station_length);
00433       max_speed = min(max_speed, st_max_speed);
00434     }
00435   }
00436 
00437   int mass = v->u.rail.cached_weight;
00438   int power = v->u.rail.cached_power * 746;
00439   max_speed = min(max_speed, v->u.rail.cached_max_speed);
00440 
00441   int num = 0; // number of vehicles, change this into the number of axles later
00442   int incl = 0;
00443   int drag_coeff = 20; //[1e-4]
00444   for (const Vehicle *u = v; u != NULL; u = u->Next()) {
00445     num++;
00446     drag_coeff += 3;
00447 
00448     if (u->u.rail.track == TRACK_BIT_DEPOT) max_speed = min(max_speed, 61);
00449 
00450     if (HasBit(u->u.rail.flags, VRF_GOINGUP)) {
00451       incl += u->u.rail.cached_veh_weight * 60; // 3% slope, quite a bit actually
00452     } else if (HasBit(u->u.rail.flags, VRF_GOINGDOWN)) {
00453       incl -= u->u.rail.cached_veh_weight * 60;
00454     }
00455   }
00456 
00457   v->max_speed = max_speed;
00458 
00459   const int area = 120;
00460   const int friction = 35; //[1e-3]
00461   int resistance;
00462   if (v->u.rail.railtype != RAILTYPE_MAGLEV) {
00463     resistance = 13 * mass / 10;
00464     resistance += 60 * num;
00465     resistance += friction * mass * speed / 1000;
00466     resistance += (area * drag_coeff * speed * speed) / 10000;
00467   } else {
00468     resistance = (area * (drag_coeff / 2) * speed * speed) / 10000;
00469   }
00470   resistance += incl;
00471   resistance *= 4; //[N]
00472 
00473   const int max_te = v->u.rail.cached_max_te; // [N]
00474   int force;
00475   if (speed > 0) {
00476     switch (v->u.rail.railtype) {
00477       case RAILTYPE_RAIL:
00478       case RAILTYPE_ELECTRIC:
00479       case RAILTYPE_MONO:
00480         force = power / speed; //[N]
00481         force *= 22;
00482         force /= 10;
00483         if (mode == AM_ACCEL && force > max_te) force = max_te;
00484         break;
00485 
00486       default: NOT_REACHED();
00487       case RAILTYPE_MAGLEV:
00488         force = power / 25;
00489         break;
00490     }
00491   } else {
00492     /* "kickoff" acceleration */
00493     force = (mode == AM_ACCEL && v->u.rail.railtype != RAILTYPE_MAGLEV) ? min(max_te, power) : power;
00494     force = max(force, (mass * 8) + resistance);
00495   }
00496 
00497   if (mode == AM_ACCEL) {
00498     return (force - resistance) / (mass * 2);
00499   } else {
00500     return min(-force - resistance, -10000) / mass;
00501   }
00502 }
00503 
00504 void UpdateTrainAcceleration(Vehicle *v)
00505 {
00506   assert(IsFrontEngine(v));
00507 
00508   v->max_speed = v->u.rail.cached_max_speed;
00509 
00510   uint power = v->u.rail.cached_power;
00511   uint weight = v->u.rail.cached_weight;
00512   assert(weight != 0);
00513   v->acceleration = Clamp(power / weight * 4, 1, 255);
00514 }
00515 
00516 SpriteID Train::GetImage(Direction direction) const
00517 {
00518   uint8 spritenum = this->spritenum;
00519   SpriteID sprite;
00520 
00521   if (HasBit(this->u.rail.flags, VRF_REVERSE_DIRECTION)) direction = ReverseDir(direction);
00522 
00523   if (is_custom_sprite(spritenum)) {
00524     sprite = GetCustomVehicleSprite(this, (Direction)(direction + 4 * IS_CUSTOM_SECONDHEAD_SPRITE(spritenum)));
00525     if (sprite != 0) return sprite;
00526 
00527     spritenum = GetEngine(this->engine_type)->image_index;
00528   }
00529 
00530   sprite = _engine_sprite_base[spritenum] + ((direction + _engine_sprite_add[spritenum]) & _engine_sprite_and[spritenum]);
00531 
00532   if (this->cargo.Count() >= this->cargo_cap / 2U) sprite += _wagon_full_adder[spritenum];
00533 
00534   return sprite;
00535 }
00536 
00537 static SpriteID GetRailIcon(EngineID engine, bool rear_head, int &y)
00538 {
00539   Direction dir = rear_head ? DIR_E : DIR_W;
00540   uint8 spritenum = RailVehInfo(engine)->image_index;
00541 
00542   if (is_custom_sprite(spritenum)) {
00543     SpriteID sprite = GetCustomVehicleIcon(engine, dir);
00544     if (sprite != 0) {
00545       y += _traininfo_vehicle_pitch; // TODO Make this per-GRF
00546       return sprite;
00547     }
00548 
00549     spritenum = GetEngine(engine)->image_index;
00550   }
00551 
00552   if (rear_head) spritenum++;
00553 
00554   return ((6 + _engine_sprite_add[spritenum]) & _engine_sprite_and[spritenum]) + _engine_sprite_base[spritenum];
00555 }
00556 
00557 void DrawTrainEngine(int x, int y, EngineID engine, SpriteID pal)
00558 {
00559   if (RailVehInfo(engine)->railveh_type == RAILVEH_MULTIHEAD) {
00560     int yf = y;
00561     int yr = y;
00562 
00563     SpriteID spritef = GetRailIcon(engine, false, yf);
00564     SpriteID spriter = GetRailIcon(engine, true, yr);
00565     DrawSprite(spritef, pal, x - 14, yf);
00566     DrawSprite(spriter, pal, x + 15, yr);
00567   } else {
00568     SpriteID sprite = GetRailIcon(engine, false, y);
00569     DrawSprite(sprite, pal, x, y);
00570   }
00571 }
00572 
00573 static CommandCost CmdBuildRailWagon(EngineID engine, TileIndex tile, DoCommandFlag flags)
00574 {
00575   const Engine *e = GetEngine(engine);
00576   const RailVehicleInfo *rvi = &e->u.rail;
00577   CommandCost value(EXPENSES_NEW_VEHICLES, e->GetCost());
00578 
00579   /* Engines without valid cargo should not be available */
00580   if (e->GetDefaultCargoType() == CT_INVALID) return CMD_ERROR;
00581 
00582   if (flags & DC_QUERY_COST) return value;
00583 
00584   /* Check that the wagon can drive on the track in question */
00585   if (!IsCompatibleRail(rvi->railtype, GetRailType(tile))) return CMD_ERROR;
00586 
00587   uint num_vehicles = 1 + CountArticulatedParts(engine, false);
00588 
00589   /* Allow for the wagon and the articulated parts, plus one to "terminate" the list. */
00590   Vehicle **vl = AllocaM(Vehicle*, num_vehicles + 1);
00591   memset(vl, 0, sizeof(*vl) * (num_vehicles + 1));
00592 
00593   if (!Vehicle::AllocateList(vl, num_vehicles)) {
00594     return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);
00595   }
00596 
00597   if (flags & DC_EXEC) {
00598     Vehicle *v = vl[0];
00599     v->spritenum = rvi->image_index;
00600 
00601     Vehicle *u = NULL;
00602 
00603     Vehicle *w;
00604     FOR_ALL_VEHICLES(w) {
00605       if (w->type == VEH_TRAIN && w->tile == tile &&
00606           IsFreeWagon(w) && w->engine_type == engine &&
00607           !HASBITS(w->vehstatus, VS_CRASHED)) {          
00608         u = GetLastVehicleInChain(w);
00609         break;
00610       }
00611     }
00612 
00613     v = new (v) Train();
00614     v->engine_type = engine;
00615 
00616     DiagDirection dir = GetRailDepotDirection(tile);
00617 
00618     v->direction = DiagDirToDir(dir);
00619     v->tile = tile;
00620 
00621     int x = TileX(tile) * TILE_SIZE | _vehicle_initial_x_fract[dir];
00622     int y = TileY(tile) * TILE_SIZE | _vehicle_initial_y_fract[dir];
00623 
00624     v->x_pos = x;
00625     v->y_pos = y;
00626     v->z_pos = GetSlopeZ(x, y);
00627     v->owner = _current_company;
00628     v->u.rail.track = TRACK_BIT_DEPOT;
00629     v->vehstatus = VS_HIDDEN | VS_DEFPAL;
00630 
00631 //    v->subtype = 0;
00632     SetTrainWagon(v);
00633 
00634     if (u != NULL) {
00635       u->SetNext(v);
00636     } else {
00637       SetFreeWagon(v);
00638       InvalidateWindowData(WC_VEHICLE_DEPOT, v->tile);
00639     }
00640 
00641     v->cargo_type = e->GetDefaultCargoType();
00642 //    v->cargo_subtype = 0;
00643     v->cargo_cap = rvi->capacity;
00644     v->value = value.GetCost();
00645 //    v->day_counter = 0;
00646 
00647     v->u.rail.railtype = rvi->railtype;
00648 
00649     v->build_year = _cur_year;
00650     v->cur_image = 0xAC2;
00651     v->random_bits = VehicleRandomBits();
00652 
00653     v->group_id = DEFAULT_GROUP;
00654 
00655     AddArticulatedParts(vl, VEH_TRAIN);
00656 
00657     _new_vehicle_id = v->index;
00658 
00659     VehicleMove(v, false);
00660     TrainConsistChanged(v->First(), false);
00661     UpdateTrainGroupID(v->First());
00662 
00663     InvalidateWindow(WC_VEHICLE_DEPOT, v->tile);
00664     if (IsLocalCompany()) {
00665       InvalidateAutoreplaceWindow(v->engine_type, v->group_id); // updates the replace Train window
00666     }
00667     GetCompany(_current_company)->num_engines[engine]++;
00668 
00669     CheckConsistencyOfArticulatedVehicle(v);
00670   }
00671 
00672   return value;
00673 }
00674 
00676 static void NormalizeTrainVehInDepot(const Vehicle *u)
00677 {
00678   const Vehicle *v;
00679 
00680   FOR_ALL_VEHICLES(v) {
00681     if (v->type == VEH_TRAIN && IsFreeWagon(v) &&
00682         v->tile == u->tile &&
00683         v->u.rail.track == TRACK_BIT_DEPOT) {
00684       if (CmdFailed(DoCommand(0, v->index | (u->index << 16), 1, DC_EXEC,
00685           CMD_MOVE_RAIL_VEHICLE)))
00686         break;
00687     }
00688   }
00689 }
00690 
00691 static void AddRearEngineToMultiheadedTrain(Vehicle *v, Vehicle *u, bool building)
00692 {
00693   u = new (u) Train();
00694   u->direction = v->direction;
00695   u->owner = v->owner;
00696   u->tile = v->tile;
00697   u->x_pos = v->x_pos;
00698   u->y_pos = v->y_pos;
00699   u->z_pos = v->z_pos;
00700   u->u.rail.track = TRACK_BIT_DEPOT;
00701   u->vehstatus = v->vehstatus & ~VS_STOPPED;
00702 //  u->subtype = 0;
00703   SetMultiheaded(u);
00704   u->spritenum = v->spritenum + 1;
00705   u->cargo_type = v->cargo_type;
00706   u->cargo_subtype = v->cargo_subtype;
00707   u->cargo_cap = v->cargo_cap;
00708   u->u.rail.railtype = v->u.rail.railtype;
00709   if (building) v->SetNext(u);
00710   u->engine_type = v->engine_type;
00711   u->build_year = v->build_year;
00712   if (building) v->value >>= 1;
00713   u->value = v->value;
00714   u->cur_image = 0xAC2;
00715   u->random_bits = VehicleRandomBits();
00716   VehicleMove(u, false);
00717 }
00718 
00725 CommandCost CmdBuildRailVehicle(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
00726 {
00727   /* Check if the engine-type is valid (for the company) */
00728   if (!IsEngineBuildable(p1, VEH_TRAIN, _current_company)) return_cmd_error(STR_RAIL_VEHICLE_NOT_AVAILABLE);
00729 
00730   const Engine *e = GetEngine(p1);
00731   CommandCost value(EXPENSES_NEW_VEHICLES, e->GetCost());
00732 
00733   /* Engines with CT_INVALID should not be available */
00734   if (e->GetDefaultCargoType() == CT_INVALID) return CMD_ERROR;
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 = e->GetDefaultCargoType();
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     VehicleMove(v, false);
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     CheckConsistencyOfArticulatedVehicle(v);
00851   }
00852 
00853   return value;
00854 }
00855 
00856 
00857 /* Check if all the wagons of the given train are in a depot, returns the
00858  * number of cars (including loco) then. If not it returns -1 */
00859 int CheckTrainInDepot(const Vehicle *v, bool needs_to_be_stopped)
00860 {
00861   TileIndex tile = v->tile;
00862 
00863   /* check if stopped in a depot */
00864   if (!IsRailDepotTile(tile) || v->cur_speed != 0) return -1;
00865 
00866   int count = 0;
00867   for (; v != NULL; v = v->Next()) {
00868     /* This count is used by the depot code to determine the number of engines
00869      * in the consist. Exclude articulated parts so that autoreplacing to
00870      * engines with more articulated parts than before works correctly.
00871      *
00872      * Also skip counting rear ends of multiheaded engines */
00873     if (!IsArticulatedPart(v) && !IsRearDualheaded(v)) count++;
00874     if (v->u.rail.track != TRACK_BIT_DEPOT || v->tile != tile ||
00875         (IsFrontEngine(v) && needs_to_be_stopped && !(v->vehstatus & VS_STOPPED))) {
00876       return -1;
00877     }
00878   }
00879 
00880   return count;
00881 }
00882 
00883 /* Used to check if the train is inside the depot and verifying that the VS_STOPPED flag is set */
00884 int CheckTrainStoppedInDepot(const Vehicle *v)
00885 {
00886   return CheckTrainInDepot(v, true);
00887 }
00888 
00889 /* Used to check if the train is inside the depot, but not checking the VS_STOPPED flag */
00890 inline bool CheckTrainIsInsideDepot(const Vehicle *v)
00891 {
00892   return CheckTrainInDepot(v, false) > 0;
00893 }
00894 
00901 static Vehicle *UnlinkWagon(Vehicle *v, Vehicle *first)
00902 {
00903   /* unlinking the first vehicle of the chain? */
00904   if (v == first) {
00905     v = GetNextVehicle(v);
00906     if (v == NULL) return NULL;
00907 
00908     if (IsTrainWagon(v)) SetFreeWagon(v);
00909 
00910     /* First can be an articulated engine, meaning GetNextVehicle() isn't
00911      * v->Next(). Thus set the next vehicle of the last articulated part
00912      * and the last articulated part is just before the next vehicle (v). */
00913     v->Previous()->SetNext(NULL);
00914 
00915     return v;
00916   }
00917 
00918   Vehicle *u;
00919   for (u = first; GetNextVehicle(u) != v; u = GetNextVehicle(u)) {}
00920   GetLastEnginePart(u)->SetNext(GetNextVehicle(v));
00921   return first;
00922 }
00923 
00924 static Vehicle *FindGoodVehiclePos(const Vehicle *src)
00925 {
00926   Vehicle *dst;
00927   EngineID eng = src->engine_type;
00928   TileIndex tile = src->tile;
00929 
00930   FOR_ALL_VEHICLES(dst) {
00931     if (dst->type == VEH_TRAIN && IsFreeWagon(dst) && dst->tile == tile && !HASBITS(dst->vehstatus, VS_CRASHED)) {
00932       /* check so all vehicles in the line have the same engine. */
00933       Vehicle *v = dst;
00934 
00935       while (v->engine_type == eng) {
00936         v = v->Next();
00937         if (v == NULL) return dst;
00938       }
00939     }
00940   }
00941 
00942   return NULL;
00943 }
00944 
00945 /*
00946  * add a vehicle v behind vehicle dest
00947  * use this function since it sets flags as needed
00948  */
00949 static void AddWagonToConsist(Vehicle *v, Vehicle *dest)
00950 {
00951   UnlinkWagon(v, v->First());
00952   if (dest == NULL) return;
00953 
00954   Vehicle *next = dest->Next();
00955   v->SetNext(NULL);
00956   dest->SetNext(v);
00957   v->SetNext(next);
00958   ClearFreeWagon(v);
00959   ClearFrontEngine(v);
00960 }
00961 
00962 /*
00963  * move around on the train so rear engines are placed correctly according to the other engines
00964  * always call with the front engine
00965  */
00966 static void NormaliseTrainConsist(Vehicle *v)
00967 {
00968   if (IsFreeWagon(v)) return;
00969 
00970   assert(IsFrontEngine(v));
00971 
00972   for (; v != NULL; v = GetNextVehicle(v)) {
00973     if (!IsMultiheaded(v) || !IsTrainEngine(v)) continue;
00974 
00975     /* make sure that there are no free cars before next engine */
00976     Vehicle *u;
00977     for (u = v; u->Next() != NULL && !IsTrainEngine(u->Next()); u = u->Next()) {}
00978 
00979     if (u == v->u.rail.other_multiheaded_part) continue;
00980     AddWagonToConsist(v->u.rail.other_multiheaded_part, u);
00981   }
00982 }
00983 
00993 CommandCost CmdMoveRailVehicle(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
00994 {
00995   VehicleID s = GB(p1, 0, 16);
00996   VehicleID d = GB(p1, 16, 16);
00997 
00998   if (!IsValidVehicleID(s)) return CMD_ERROR;
00999 
01000   Vehicle *src = GetVehicle(s);
01001 
01002   if (src->type != VEH_TRAIN || !CheckOwnership(src->owner)) return CMD_ERROR;
01003 
01004   /* Do not allow moving crashed vehicles inside the depot, it is likely to cause asserts later */
01005   if (HASBITS(src->vehstatus, VS_CRASHED)) return CMD_ERROR;
01006 
01007   /* if nothing is selected as destination, try and find a matching vehicle to drag to. */
01008   Vehicle *dst;
01009   if (d == INVALID_VEHICLE) {
01010     dst = IsTrainEngine(src) ? NULL : FindGoodVehiclePos(src);
01011   } else {
01012     if (!IsValidVehicleID(d)) return CMD_ERROR;
01013     dst = GetVehicle(d);
01014     if (dst->type != VEH_TRAIN || !CheckOwnership(dst->owner)) return CMD_ERROR;
01015 
01016     /* Do not allow appending to crashed vehicles, too */
01017     if (HASBITS(dst->vehstatus, VS_CRASHED)) return CMD_ERROR;
01018   }
01019 
01020   /* if an articulated part is being handled, deal with its parent vehicle */
01021   while (IsArticulatedPart(src)) src = src->Previous();
01022   if (dst != NULL) {
01023     while (IsArticulatedPart(dst)) dst = dst->Previous();
01024   }
01025 
01026   /* don't move the same vehicle.. */
01027   if (src == dst) return CommandCost();
01028 
01029   /* locate the head of the two chains */
01030   Vehicle *src_head = src->First();
01031   Vehicle *dst_head;
01032   if (dst != NULL) {
01033     dst_head = dst->First();
01034     if (dst_head->tile != src_head->tile) return CMD_ERROR;
01035     /* Now deal with articulated part of destination wagon */
01036     dst = GetLastEnginePart(dst);
01037   } else {
01038     dst_head = NULL;
01039   }
01040 
01041   if (IsRearDualheaded(src)) return_cmd_error(STR_REAR_ENGINE_FOLLOW_FRONT_ERROR);
01042 
01043   /* when moving all wagons, we can't have the same src_head and dst_head */
01044   if (HasBit(p2, 0) && src_head == dst_head) return CommandCost();
01045 
01046   /* check if all vehicles in the source train are stopped inside a depot. */
01047   int src_len = CheckTrainStoppedInDepot(src_head);
01048   if (src_len < 0) return_cmd_error(STR_881A_TRAINS_CAN_ONLY_BE_ALTERED);
01049 
01050   if ((flags & DC_AUTOREPLACE) == 0) {
01051     /* Check whether there are more than 'max_len' train units (articulated parts and rear heads do not count) in the new chain */
01052     int max_len = _settings_game.vehicle.mammoth_trains ? 100 : 10;
01053 
01054     /* check the destination row if the source and destination aren't the same. */
01055     if (src_head != dst_head) {
01056       int dst_len = 0;
01057 
01058       if (dst_head != NULL) {
01059         /* check if all vehicles in the dest train are stopped. */
01060         dst_len = CheckTrainStoppedInDepot(dst_head);
01061         if (dst_len < 0) return_cmd_error(STR_881A_TRAINS_CAN_ONLY_BE_ALTERED);
01062       }
01063 
01064       /* We are moving between rows, so only count the wagons from the source
01065        * row that are being moved. */
01066       if (HasBit(p2, 0)) {
01067         const Vehicle *u;
01068         for (u = src_head; u != src && u != NULL; u = GetNextVehicle(u))
01069           src_len--;
01070       } else {
01071         /* If moving only one vehicle, just count that. */
01072         src_len = 1;
01073       }
01074 
01075       if (src_len + dst_len > max_len) {
01076         /* Abort if we're adding too many wagons to a train. */
01077         if (dst_head != NULL && IsFrontEngine(dst_head)) return_cmd_error(STR_8819_TRAIN_TOO_LONG);
01078         /* Abort if we're making a train on a new row. */
01079         if (dst_head == NULL && IsTrainEngine(src)) return_cmd_error(STR_8819_TRAIN_TOO_LONG);
01080       }
01081     } else {
01082       /* Abort if we're creating a new train on an existing row. */
01083       if (src_len > max_len && src == src_head && IsTrainEngine(GetNextVehicle(src_head)))
01084         return_cmd_error(STR_8819_TRAIN_TOO_LONG);
01085     }
01086   }
01087 
01088   /* moving a loco to a new line?, then we need to assign a unitnumber. */
01089   if (dst == NULL && !IsFrontEngine(src) && IsTrainEngine(src)) {
01090     UnitID unit_num = ((flags & DC_AUTOREPLACE) != 0 ? 0 : GetFreeUnitNumber(VEH_TRAIN));
01091     if (unit_num > _settings_game.vehicle.max_trains)
01092       return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);
01093 
01094     if (flags & DC_EXEC) src->unitnumber = unit_num;
01095   }
01096 
01097   /* When we move the front vehicle, the second vehicle might need a unitnumber */
01098   if (!HasBit(p2, 0) && (IsFreeWagon(src) || (IsFrontEngine(src) && dst == NULL)) && (flags & DC_AUTOREPLACE) == 0) {
01099     Vehicle *second = GetNextUnit(src);
01100     if (second != NULL && IsTrainEngine(second) && GetFreeUnitNumber(VEH_TRAIN) > _settings_game.vehicle.max_trains) {
01101       return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);
01102     }
01103   }
01104 
01105   /*
01106    * Check whether the vehicles in the source chain are in the destination
01107    * chain. This can easily be done by checking whether the first vehicle
01108    * of the source chain is in the destination chain as the Next/Previous
01109    * pointers always make a doubly linked list of it where the assumption
01110    * v->Next()->Previous() == v holds (assuming v->Next() != NULL).
01111    */
01112   bool src_in_dst = false;
01113   for (Vehicle *v = dst_head; !src_in_dst && v != NULL; v = v->Next()) src_in_dst = v == src;
01114 
01115   /*
01116    * If the source chain is in the destination chain then the user is
01117    * only reordering the vehicles, thus not attaching a new vehicle.
01118    * Therefor the 'allow wagon attach' callback does not need to be
01119    * called. If it would be called strange things would happen because
01120    * one 'attaches' an already 'attached' vehicle causing more trouble
01121    * than it actually solves (infinite loops and such).
01122    */
01123   if (dst_head != NULL && !src_in_dst && (flags & DC_AUTOREPLACE) == 0) {
01124     /*
01125      * When performing the 'allow wagon attach' callback, we have to check
01126      * that for each and every wagon, not only the first one. This means
01127      * that we have to test one wagon, attach it to the train and then test
01128      * the next wagon till we have reached the end. We have to restore it
01129      * to the state it was before we 'tried' attaching the train when the
01130      * attaching fails or succeeds because we are not 'only' doing this
01131      * in the DC_EXEC state.
01132      */
01133     Vehicle *dst_tail = dst_head;
01134     while (dst_tail->Next() != NULL) dst_tail = dst_tail->Next();
01135 
01136     Vehicle *orig_tail = dst_tail;
01137     Vehicle *next_to_attach = src;
01138     Vehicle *src_previous = src->Previous();
01139 
01140     while (next_to_attach != NULL) {
01141       /* Don't check callback for articulated or rear dual headed parts */
01142       if (!IsArticulatedPart(next_to_attach) && !IsRearDualheaded(next_to_attach)) {
01143         /* Back up and clear the first_engine data to avoid using wagon override group */
01144         EngineID first_engine = next_to_attach->u.rail.first_engine;
01145         next_to_attach->u.rail.first_engine = INVALID_ENGINE;
01146 
01147         uint16 callback = GetVehicleCallbackParent(CBID_TRAIN_ALLOW_WAGON_ATTACH, 0, 0, dst_head->engine_type, next_to_attach, dst_head);
01148 
01149         /* Restore original first_engine data */
01150         next_to_attach->u.rail.first_engine = first_engine;
01151 
01152         if (callback != CALLBACK_FAILED) {
01153           StringID error = STR_NULL;
01154 
01155           if (callback == 0xFD) error = STR_INCOMPATIBLE_RAIL_TYPES;
01156           if (callback < 0xFD) error = GetGRFStringID(GetEngineGRFID(dst_head->engine_type), 0xD000 + callback);
01157 
01158           if (error != STR_NULL) {
01159             /*
01160              * The attaching is not allowed. In this case 'next_to_attach'
01161              * can contain some vehicles of the 'source' and the destination
01162              * train can have some too. We 'just' add the to-be added wagons
01163              * to the chain and then split it where it was previously
01164              * separated, i.e. the tail of the original destination train.
01165              * Furthermore the 'previous' link of the original source vehicle needs
01166              * to be restored, otherwise the train goes missing in the depot.
01167              */
01168             dst_tail->SetNext(next_to_attach);
01169             orig_tail->SetNext(NULL);
01170             if (src_previous != NULL) src_previous->SetNext(src);
01171 
01172             return_cmd_error(error);
01173           }
01174         }
01175       }
01176 
01177       /* Only check further wagons if told to move the chain */
01178       if (!HasBit(p2, 0)) break;
01179 
01180       /*
01181        * Adding a next wagon to the chain so we can test the other wagons.
01182        * First 'take' the first wagon from 'next_to_attach' and move it
01183        * to the next wagon. Then add that to the tail of the destination
01184        * train and update the tail with the new vehicle.
01185        */
01186       Vehicle *to_add = next_to_attach;
01187       next_to_attach = next_to_attach->Next();
01188 
01189       to_add->SetNext(NULL);
01190       dst_tail->SetNext(to_add);
01191       dst_tail = dst_tail->Next();
01192     }
01193 
01194     /*
01195      * When we reach this the attaching is allowed. It also means that the
01196      * chain of vehicles to attach is empty, so we do not need to merge that.
01197      * This means only the splitting needs to be done.
01198      * Furthermore the 'previous' link of the original source vehicle needs
01199      * to be restored, otherwise the train goes missing in the depot.
01200      */
01201     orig_tail->SetNext(NULL);
01202     if (src_previous != NULL) src_previous->SetNext(src);
01203   }
01204 
01205   /* do it? */
01206   if (flags & DC_EXEC) {
01207     /* If we move the front Engine and if the second vehicle is not an engine
01208        add the whole vehicle to the DEFAULT_GROUP */
01209     if (IsFrontEngine(src) && !IsDefaultGroupID(src->group_id)) {
01210       Vehicle *v = GetNextVehicle(src);
01211 
01212       if (v != NULL && IsTrainEngine(v)) {
01213         v->group_id   = src->group_id;
01214         src->group_id = DEFAULT_GROUP;
01215       }
01216     }
01217 
01218     if (HasBit(p2, 0)) {
01219       /* unlink ALL wagons */
01220       if (src != src_head) {
01221         Vehicle *v = src_head;
01222         while (GetNextVehicle(v) != src) v = GetNextVehicle(v);
01223         GetLastEnginePart(v)->SetNext(NULL);
01224       } else {
01225         InvalidateWindowData(WC_VEHICLE_DEPOT, src_head->tile); // We removed a line
01226         src_head = NULL;
01227       }
01228     } else {
01229       /* if moving within the same chain, dont use dst_head as it may get invalidated */
01230       if (src_head == dst_head) dst_head = NULL;
01231       /* unlink single wagon from linked list */
01232       src_head = UnlinkWagon(src, src_head);
01233       GetLastEnginePart(src)->SetNext(NULL);
01234     }
01235 
01236     if (dst == NULL) {
01237       /* We make a new line in the depot, so we know already that we invalidate the window data */
01238       InvalidateWindowData(WC_VEHICLE_DEPOT, src->tile);
01239 
01240       /* move the train to an empty line. for locomotives, we set the type to TS_Front. for wagons, 4. */
01241       if (IsTrainEngine(src)) {
01242         if (!IsFrontEngine(src)) {
01243           /* setting the type to 0 also involves setting up the orders field. */
01244           SetFrontEngine(src);
01245           assert(src->orders.list == NULL);
01246 
01247           /* Decrease the engines number of the src engine_type */
01248           if (!IsDefaultGroupID(src->group_id) && IsValidGroupID(src->group_id)) {
01249             GetGroup(src->group_id)->num_engines[src->engine_type]--;
01250           }
01251 
01252           /* If we move an engine to a new line affect it to the DEFAULT_GROUP */
01253           src->group_id = DEFAULT_GROUP;
01254         }
01255       } else {
01256         SetFreeWagon(src);
01257       }
01258       dst_head = src;
01259     } else {
01260       if (IsFrontEngine(src)) {
01261         /* the vehicle was previously a loco. need to free the order list and delete vehicle windows etc. */
01262         DeleteWindowById(WC_VEHICLE_VIEW, src->index);
01263         DeleteWindowById(WC_VEHICLE_ORDERS, src->index);
01264         DeleteWindowById(WC_VEHICLE_REFIT, src->index);
01265         DeleteWindowById(WC_VEHICLE_DETAILS, src->index);
01266         DeleteWindowById(WC_VEHICLE_TIMETABLE, src->index);
01267         DeleteVehicleOrders(src);
01268         RemoveVehicleFromGroup(src);
01269       }
01270 
01271       if (IsFrontEngine(src) || IsFreeWagon(src)) {
01272         InvalidateWindowData(WC_VEHICLE_DEPOT, src->tile);
01273         ClearFrontEngine(src);
01274         ClearFreeWagon(src);
01275         src->unitnumber = 0; // doesn't occupy a unitnumber anymore.
01276       }
01277 
01278       /* link in the wagon(s) in the chain. */
01279       {
01280         Vehicle *v;
01281 
01282         for (v = src; GetNextVehicle(v) != NULL; v = GetNextVehicle(v)) {}
01283         GetLastEnginePart(v)->SetNext(dst->Next());
01284       }
01285       dst->SetNext(src);
01286     }
01287 
01288     if (src->u.rail.other_multiheaded_part != NULL) {
01289       if (src->u.rail.other_multiheaded_part == src_head) {
01290         src_head = src_head->Next();
01291       }
01292       AddWagonToConsist(src->u.rail.other_multiheaded_part, src);
01293     }
01294 
01295     /* If there is an engine behind first_engine we moved away, it should become new first_engine
01296      * To do this, CmdMoveRailVehicle must be called once more
01297      * we can't loop forever here because next time we reach this line we will have a front engine */
01298     if (src_head != NULL && !IsFrontEngine(src_head) && IsTrainEngine(src_head)) {
01299       /* As in CmdMoveRailVehicle src_head->group_id will be equal to DEFAULT_GROUP
01300        * we need to save the group and reaffect it to src_head */
01301       const GroupID tmp_g = src_head->group_id;
01302       CmdMoveRailVehicle(0, flags, src_head->index | (INVALID_VEHICLE << 16), 1, text);
01303       SetTrainGroupID(src_head, tmp_g);
01304       src_head = NULL; // don't do anything more to this train since the new call will do it
01305     }
01306 
01307     if (src_head != NULL) {
01308       NormaliseTrainConsist(src_head);
01309       TrainConsistChanged(src_head, false);
01310       UpdateTrainGroupID(src_head);
01311       if (IsFrontEngine(src_head)) {
01312         /* Update the refit button and window */
01313         InvalidateWindow(WC_VEHICLE_REFIT, src_head->index);
01314         InvalidateWindowWidget(WC_VEHICLE_VIEW, src_head->index, VVW_WIDGET_REFIT_VEH);
01315       }
01316       /* Update the depot window */
01317       InvalidateWindow(WC_VEHICLE_DEPOT, src_head->tile);
01318     }
01319 
01320     if (dst_head != NULL) {
01321       NormaliseTrainConsist(dst_head);
01322       TrainConsistChanged(dst_head, false);
01323       UpdateTrainGroupID(dst_head);
01324       if (IsFrontEngine(dst_head)) {
01325         /* Update the refit button and window */
01326         InvalidateWindowWidget(WC_VEHICLE_VIEW, dst_head->index, VVW_WIDGET_REFIT_VEH);
01327         InvalidateWindow(WC_VEHICLE_REFIT, dst_head->index);
01328       }
01329       /* Update the depot window */
01330       InvalidateWindow(WC_VEHICLE_DEPOT, dst_head->tile);
01331     }
01332 
01333     InvalidateWindowClassesData(WC_TRAINS_LIST, 0);
01334   }
01335 
01336   return CommandCost();
01337 }
01338 
01348 CommandCost CmdSellRailWagon(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
01349 {
01350   /* Check if we deleted a vehicle window */
01351   Window *w = NULL;
01352 
01353   if (!IsValidVehicleID(p1) || p2 > 1) return CMD_ERROR;
01354 
01355   Vehicle *v = GetVehicle(p1);
01356 
01357   if (v->type != VEH_TRAIN || !CheckOwnership(v->owner)) return CMD_ERROR;
01358 
01359   if (HASBITS(v->vehstatus, VS_CRASHED)) return_cmd_error(STR_CAN_T_SELL_DESTROYED_VEHICLE);
01360 
01361   while (IsArticulatedPart(v)) v = v->Previous();
01362   Vehicle *first = v->First();
01363 
01364   /* make sure the vehicle is stopped in the depot */
01365   if (CheckTrainStoppedInDepot(first) < 0) {
01366     return_cmd_error(STR_881A_TRAINS_CAN_ONLY_BE_ALTERED);
01367   }
01368 
01369   if (IsRearDualheaded(v)) return_cmd_error(STR_REAR_ENGINE_FOLLOW_FRONT_ERROR);
01370 
01371   if (flags & DC_EXEC) {
01372     if (v == first && IsFrontEngine(first)) {
01373       DeleteWindowById(WC_VEHICLE_VIEW, first->index);
01374       DeleteWindowById(WC_VEHICLE_ORDERS, first->index);
01375       DeleteWindowById(WC_VEHICLE_REFIT, first->index);
01376       DeleteWindowById(WC_VEHICLE_DETAILS, first->index);
01377       DeleteWindowById(WC_VEHICLE_TIMETABLE, first->index);
01378     }
01379     InvalidateWindow(WC_VEHICLE_DEPOT, first->tile);
01380     InvalidateWindowClassesData(WC_TRAINS_LIST, 0);
01381   }
01382 
01383   CommandCost cost(EXPENSES_NEW_VEHICLES);
01384   switch (p2) {
01385     case 0: { // Delete given wagon
01386       bool switch_engine = false;    // update second wagon to engine?
01387 
01388       /* 1. Delete the engine, if it is dualheaded also delete the matching
01389        * rear engine of the loco (from the point of deletion onwards) */
01390       Vehicle *rear = (IsMultiheaded(v) &&
01391         IsTrainEngine(v)) ? v->u.rail.other_multiheaded_part : NULL;
01392 
01393       if (rear != NULL) {
01394         cost.AddCost(-rear->value);
01395         if (flags & DC_EXEC) {
01396           UnlinkWagon(rear, first);
01397           delete rear;
01398         }
01399       }
01400 
01401       /* 2. We are selling the front vehicle, some special action might be required
01402        * here, so take attention */
01403       if (v == first) {
01404         Vehicle *new_f = GetNextVehicle(first);
01405 
01406         /* 2.2 If there are wagons present after the deleted front engine, check
01407          * if the second wagon (which will be first) is an engine. If it is one,
01408          * promote it as a new train, retaining the unitnumber, orders */
01409         if (new_f != NULL && IsTrainEngine(new_f)) {
01410           if (IsTrainEngine(first)) {
01411             /* Let the new front engine take over the setup of the old engine */
01412             switch_engine = true;
01413 
01414             if (flags & DC_EXEC) {
01415               /* Make sure the group counts stay correct. */
01416               new_f->group_id        = first->group_id;
01417               first->group_id        = DEFAULT_GROUP;
01418 
01419               /* Copy orders (by sharing) */
01420               new_f->orders.list     = first->orders.list;
01421               new_f->AddToShared(first);
01422               DeleteVehicleOrders(first);
01423 
01424               /* Copy other important data from the front engine */
01425               new_f->CopyVehicleConfigAndStatistics(first);
01426 
01427               /* If we deleted a window then open a new one for the 'new' train */
01428               if (IsLocalCompany() && w != NULL) ShowVehicleViewWindow(new_f);
01429             }
01430           } else {
01431             /* We are selling a free wagon, and construct a new train at the same time.
01432              * This needs lots of extra checks (e.g. train limit), which are done by first moving
01433              * the remaining vehicles to a new row */
01434             cost.AddCost(DoCommand(0, new_f->index | INVALID_VEHICLE << 16, 1, flags, CMD_MOVE_RAIL_VEHICLE));
01435             if (cost.Failed()) return cost;
01436           }
01437         }
01438       }
01439 
01440       /* 3. Delete the requested wagon */
01441       cost.AddCost(-v->value);
01442       if (flags & DC_EXEC) {
01443         first = UnlinkWagon(v, first);
01444         delete v;
01445 
01446         /* 4 If the second wagon was an engine, update it to front_engine
01447          * which UnlinkWagon() has changed to TS_Free_Car */
01448         if (switch_engine) SetFrontEngine(first);
01449 
01450         /* 5. If the train still exists, update its acceleration, window, etc. */
01451         if (first != NULL) {
01452           NormaliseTrainConsist(first);
01453           TrainConsistChanged(first, false);
01454           UpdateTrainGroupID(first);
01455           if (IsFrontEngine(first)) InvalidateWindow(WC_VEHICLE_REFIT, first->index);
01456         }
01457 
01458       }
01459     } break;
01460     case 1: { // Delete wagon and all wagons after it given certain criteria
01461       /* Start deleting every vehicle after the selected one
01462        * If we encounter a matching rear-engine to a front-engine
01463        * earlier in the chain (before deletion), leave it alone */
01464       for (Vehicle *tmp; v != NULL; v = tmp) {
01465         tmp = GetNextVehicle(v);
01466 
01467         if (IsMultiheaded(v)) {
01468           if (IsTrainEngine(v)) {
01469             /* We got a front engine of a multiheaded set. Now we will sell the rear end too */
01470             Vehicle *rear = v->u.rail.other_multiheaded_part;
01471 
01472             if (rear != NULL) {
01473               cost.AddCost(-rear->value);
01474 
01475               /* If this is a multiheaded vehicle with nothing
01476                * between the parts, tmp will be pointing to the
01477                * rear part, which is unlinked from the train and
01478                * deleted here. However, because tmp has already
01479                * been set it needs to be updated now so that the
01480                * loop never sees the rear part. */
01481               if (tmp == rear) tmp = GetNextVehicle(tmp);
01482 
01483               if (flags & DC_EXEC) {
01484                 first = UnlinkWagon(rear, first);
01485                 delete rear;
01486               }
01487             }
01488           } else if (v->u.rail.other_multiheaded_part != NULL) {
01489             /* The front to this engine is earlier in this train. Do nothing */
01490             continue;
01491           }
01492         }
01493 
01494         cost.AddCost(-v->value);
01495         if (flags & DC_EXEC) {
01496           first = UnlinkWagon(v, first);
01497           delete v;
01498         }
01499       }
01500 
01501       /* 3. If it is still a valid train after selling, update its acceleration and cached values */
01502       if (flags & DC_EXEC && first != NULL) {
01503         NormaliseTrainConsist(first);
01504         TrainConsistChanged(first, false);
01505         UpdateTrainGroupID(first);
01506         InvalidateWindow(WC_VEHICLE_REFIT, first->index);
01507       }
01508     } break;
01509   }
01510   return cost;
01511 }
01512 
01513 void Train::UpdateDeltaXY(Direction direction)
01514 {
01515 #define MKIT(a, b, c, d) ((a & 0xFF) << 24) | ((b & 0xFF) << 16) | ((c & 0xFF) << 8) | ((d & 0xFF) << 0)
01516   static const uint32 _delta_xy_table[8] = {
01517     MKIT(3, 3, -1, -1),
01518     MKIT(3, 7, -1, -3),
01519     MKIT(3, 3, -1, -1),
01520     MKIT(7, 3, -3, -1),
01521     MKIT(3, 3, -1, -1),
01522     MKIT(3, 7, -1, -3),
01523     MKIT(3, 3, -1, -1),
01524     MKIT(7, 3, -3, -1),
01525   };
01526 #undef MKIT
01527 
01528   uint32 x = _delta_xy_table[direction];
01529   this->x_offs        = GB(x,  0, 8);
01530   this->y_offs        = GB(x,  8, 8);
01531   this->x_extent      = GB(x, 16, 8);
01532   this->y_extent      = GB(x, 24, 8);
01533   this->z_extent      = 6;
01534 }
01535 
01536 static void UpdateVarsAfterSwap(Vehicle *v)
01537 {
01538   v->UpdateDeltaXY(v->direction);
01539   v->cur_image = v->GetImage(v->direction);
01540   VehicleMove(v, true);
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());
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); // 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));
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     const Engine *e = GetEngine(v->engine_type);
02019     if (e->CanCarryCargo()) {
02020       uint16 amount = CALLBACK_FAILED;
02021 
02022       if (HasBit(EngInfo(v->engine_type)->callbackmask, CBM_VEHICLE_REFIT_CAPACITY)) {
02023         /* Back up the vehicle's cargo type */
02024         CargoID temp_cid = v->cargo_type;
02025         byte temp_subtype = v->cargo_subtype;
02026         v->cargo_type = new_cid;
02027         v->cargo_subtype = new_subtype;
02028         /* Check the refit capacity callback */
02029         amount = GetVehicleCallback(CBID_VEHICLE_REFIT_CAPACITY, 0, 0, v->engine_type, v);
02030         /* Restore the original cargo type */
02031         v->cargo_type = temp_cid;
02032         v->cargo_subtype = temp_subtype;
02033       }
02034 
02035       if (amount == CALLBACK_FAILED) { // callback failed or not used, use default
02036         CargoID old_cid = e->GetDefaultCargoType();
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 = e->u.rail.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   /* We are leaving a depot, but have to go to the exact same one; re-enter */
02390   if (v->tile == v->dest_tile) {
02391     /* We need to have a reservation for this to work. */
02392     if (GetDepotWaypointReservation(v->tile)) return true;
02393     SetDepotWaypointReservation(v->tile, true);
02394     VehicleEnterDepot(v);
02395     return true;
02396   }
02397 
02398   /* Only leave when we can reserve a path to our destination. */
02399   if (seg_state == SIGSEG_PBS && !TryPathReserve(v) && v->u.rail.force_proceed == 0) {
02400     /* No path and no force proceed. */
02401     InvalidateWindowClasses(WC_TRAINS_LIST);
02402     MarkTrainAsStuck(v);
02403     return true;
02404   }
02405 
02406   SetDepotWaypointReservation(v->tile, true);
02407   if (_settings_client.gui.show_track_reservation) MarkTileDirtyByTile(v->tile);
02408 
02409   VehicleServiceInDepot(v);
02410   InvalidateWindowClasses(WC_TRAINS_LIST);
02411   v->PlayLeaveStationSound();
02412 
02413   v->u.rail.track = TRACK_BIT_X;
02414   if (v->direction & 2) v->u.rail.track = TRACK_BIT_Y;
02415 
02416   v->vehstatus &= ~VS_HIDDEN;
02417   v->cur_speed = 0;
02418 
02419   v->UpdateDeltaXY(v->direction);
02420   v->cur_image = v->GetImage(v->direction);
02421   VehicleMove(v, false);
02422   UpdateSignalsOnSegment(v->tile, INVALID_DIAGDIR, v->owner);
02423   UpdateTrainAcceleration(v);
02424   InvalidateWindowData(WC_VEHICLE_DEPOT, v->tile);
02425 
02426   return false;
02427 }
02428 
02430 static void ClearPathReservation(const Vehicle *v, TileIndex tile, Trackdir track_dir)
02431 {
02432   DiagDirection dir = TrackdirToExitdir(track_dir);
02433 
02434   if (IsTileType(tile, MP_TUNNELBRIDGE)) {
02435     /* Are we just leaving a tunnel/bridge? */
02436     if (GetTunnelBridgeDirection(tile) == ReverseDiagDir(dir)) {
02437       TileIndex end = GetOtherTunnelBridgeEnd(tile);
02438 
02439       if (!HasVehicleOnTunnelBridge(tile, end, v)) {
02440         /* Free the reservation only if no other train is on the tiles. */
02441         SetTunnelBridgeReservation(tile, false);
02442         SetTunnelBridgeReservation(end, false);
02443 
02444         if (_settings_client.gui.show_track_reservation) {
02445           MarkTileDirtyByTile(tile);
02446           MarkTileDirtyByTile(end);
02447         }
02448       }
02449     }
02450   } else if (IsRailwayStationTile(tile)) {
02451     TileIndex new_tile = TileAddByDiagDir(tile, dir);
02452     /* If the new tile is not a further tile of the same station, we
02453      * clear the reservation for the whole platform. */
02454     if (!IsCompatibleTrainStationTile(new_tile, tile)) {
02455       SetRailwayStationPlatformReservation(tile, ReverseDiagDir(dir), false);
02456     }
02457   } else {
02458     /* Any other tile */
02459     UnreserveRailTrack(tile, TrackdirToTrack(track_dir));
02460   }
02461 }
02462 
02464 void FreeTrainTrackReservation(const Vehicle *v, TileIndex origin, Trackdir orig_td)
02465 {
02466   assert(IsFrontEngine(v));
02467 
02468   TileIndex tile = origin != INVALID_TILE ? origin : v->tile;
02469   Trackdir  td = orig_td != INVALID_TRACKDIR ? orig_td : GetVehicleTrackdir(v);
02470   bool      free_tile = tile != v->tile || !(IsRailwayStationTile(v->tile) || IsTileType(v->tile, MP_TUNNELBRIDGE));
02471   StationID station_id = IsRailwayStationTile(v->tile) ? GetStationIndex(v->tile) : INVALID_STATION;
02472 
02473   /* Don't free reservation if it's not ours. */
02474   if (TracksOverlap(GetReservedTrackbits(tile) | TrackToTrackBits(TrackdirToTrack(td)))) return;
02475 
02476   CFollowTrackRail ft(v, GetRailTypeInfo(v->u.rail.railtype)->compatible_railtypes);
02477   while (ft.Follow(tile, td)) {
02478     tile = ft.m_new_tile;
02479     TrackdirBits bits = ft.m_new_td_bits & TrackBitsToTrackdirBits(GetReservedTrackbits(tile));
02480     td = RemoveFirstTrackdir(&bits);
02481     assert(bits == TRACKDIR_BIT_NONE);
02482 
02483     if (!IsValidTrackdir(td)) break;
02484 
02485     if (IsTileType(tile, MP_RAILWAY)) {
02486       if (HasSignalOnTrackdir(tile, td) && !IsPbsSignal(GetSignalType(tile, TrackdirToTrack(td)))) {
02487         /* Conventional signal along trackdir: remove reservation and stop. */
02488         UnreserveRailTrack(tile, TrackdirToTrack(td));
02489         break;
02490       }
02491       if (HasPbsSignalOnTrackdir(tile, td)) {
02492         if (GetSignalStateByTrackdir(tile, td) == SIGNAL_STATE_RED) {
02493           /* Red PBS signal? Can't be our reservation, would be green then. */
02494           break;
02495         } else {
02496           /* Turn the signal back to red. */
02497           SetSignalStateByTrackdir(tile, td, SIGNAL_STATE_RED);
02498           MarkTileDirtyByTile(tile);
02499         }
02500       } else if (HasSignalOnTrackdir(tile, ReverseTrackdir(td)) && IsOnewaySignal(tile, TrackdirToTrack(td))) {
02501         break;
02502       }
02503     }
02504 
02505     /* Don't free first station/bridge/tunnel if we are on it. */
02506     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);
02507 
02508     free_tile = true;
02509   }
02510 }
02511 
02513 struct TrainTrackFollowerData {
02514   TileIndex dest_coords;
02515   StationID station_index; 
02516   uint best_bird_dist;
02517   uint best_track_dist;
02518   TrackdirByte best_track;
02519 };
02520 
02521 static bool NtpCallbFindStation(TileIndex tile, TrainTrackFollowerData *ttfd, Trackdir track, uint length)
02522 {
02523   /* heading for nowhere? */
02524   if (ttfd->dest_coords == 0) return false;
02525 
02526   /* did we reach the final station? */
02527   if ((ttfd->station_index == INVALID_STATION && tile == ttfd->dest_coords) || (
02528         IsTileType(tile, MP_STATION) &&
02529         IsRailwayStation(tile) &&
02530         GetStationIndex(tile) == ttfd->station_index
02531       )) {
02532     /* We do not check for dest_coords if we have a station_index,
02533      * because in that case the dest_coords are just an
02534      * approximation of where the station is */
02535 
02536     /* found station */
02537     ttfd->best_track = track;
02538     ttfd->best_bird_dist = 0;
02539     return true;
02540   } else {
02541     /* didn't find station, keep track of the best path so far. */
02542     uint dist = DistanceManhattan(tile, ttfd->dest_coords);
02543     if (dist < ttfd->best_bird_dist) {
02544       ttfd->best_bird_dist = dist;
02545       ttfd->best_track = track;
02546     }
02547     return false;
02548   }
02549 }
02550 
02551 static void FillWithStationData(TrainTrackFollowerData *fd, const Vehicle *v)
02552 {
02553   fd->dest_coords = v->dest_tile;
02554   fd->station_index = v->current_order.IsType(OT_GOTO_STATION) ? v->current_order.GetDestination() : INVALID_STATION;
02555 }
02556 
02557 static const byte _initial_tile_subcoord[6][4][3] = {
02558 {{ 15, 8, 1 }, { 0, 0, 0 }, { 0, 8, 5 }, { 0,  0, 0 }},
02559 {{  0, 0, 0 }, { 8, 0, 3 }, { 0, 0, 0 }, { 8, 15, 7 }},
02560 {{  0, 0, 0 }, { 7, 0, 2 }, { 0, 7, 6 }, { 0,  0, 0 }},
02561 {{ 15, 8, 2 }, { 0, 0, 0 }, { 0, 0, 0 }, { 8, 15, 6 }},
02562 {{ 15, 7, 0 }, { 8, 0, 4 }, { 0, 0, 0 }, { 0,  0, 0 }},
02563 {{  0, 0, 0 }, { 0, 0, 0 }, { 0, 8, 4 }, { 7, 15, 0 }},
02564 };
02565 
02566 static const byte _search_directions[6][4] = {
02567   { 0, 9, 2, 9 }, 
02568   { 9, 1, 9, 3 }, 
02569   { 9, 0, 3, 9 }, 
02570   { 1, 9, 9, 2 }, 
02571   { 3, 2, 9, 9 }, 
02572   { 9, 9, 1, 0 }, 
02573 };
02574 
02575 static const byte _pick_track_table[6] = {1, 3, 2, 2, 0, 0};
02576 
02589 static Track DoTrainPathfind(Vehicle *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks, bool *path_not_found, bool do_track_reservation, PBSTileInfo *dest)
02590 {
02591   Track best_track;
02592 
02593 #ifdef PF_BENCHMARK
02594   TIC()
02595 #endif
02596 
02597   if (path_not_found) *path_not_found = false;
02598 
02599   uint8 pathfinder = _settings_game.pf.pathfinder_for_trains;
02600   if (do_track_reservation && pathfinder == VPF_NTP) pathfinder = VPF_NPF;
02601 
02602   switch (pathfinder) {
02603     case VPF_YAPF: { // YAPF
02604       Trackdir trackdir = YapfChooseRailTrack(v, tile, enterdir, tracks, path_not_found, do_track_reservation, dest);
02605       if (trackdir != INVALID_TRACKDIR) {
02606         best_track = TrackdirToTrack(trackdir);
02607       } else {
02608         best_track = FindFirstTrack(tracks);
02609       }
02610     } break;
02611 
02612     case VPF_NPF: { // NPF
02613       void *perf = NpfBeginInterval();
02614 
02615       NPFFindStationOrTileData fstd;
02616       NPFFillWithOrderData(&fstd, v, do_track_reservation);
02617 
02618       PBSTileInfo origin = FollowTrainReservation(v);
02619       assert(IsValidTrackdir(origin.trackdir));
02620 
02621       NPFFoundTargetData ftd = NPFRouteToStationOrTile(origin.tile, origin.trackdir, true, &fstd, TRANSPORT_RAIL, 0, v->owner, v->u.rail.compatible_railtypes);
02622 
02623       if (dest != NULL) {
02624         dest->tile = ftd.node.tile;
02625         dest->trackdir = (Trackdir)ftd.node.direction;
02626         dest->okay = ftd.res_okay;
02627       }
02628 
02629       if (ftd.best_trackdir == INVALID_TRACKDIR) {
02630         /* We are already at our target. Just do something
02631          * @todo maybe display error?
02632          * @todo: go straight ahead if possible? */
02633         best_track = FindFirstTrack(tracks);
02634       } else {
02635         /* If ftd.best_bird_dist is 0, we found our target and ftd.best_trackdir contains
02636          * the direction we need to take to get there, if ftd.best_bird_dist is not 0,
02637          * we did not find our target, but ftd.best_trackdir contains the direction leading
02638          * to the tile closest to our target. */
02639         if (ftd.best_bird_dist != 0 && path_not_found != NULL) *path_not_found = true;
02640         /* Discard enterdir information, making it a normal track */
02641         best_track = TrackdirToTrack(ftd.best_trackdir);
02642       }
02643 
02644       int time = NpfEndInterval(perf);
02645       DEBUG(yapf, 4, "[NPFT] %d us - %d rounds - %d open - %d closed -- ", time, 0, _aystar_stats_open_size, _aystar_stats_closed_size);
02646     } break;
02647 
02648     default:
02649     case VPF_NTP: { // NTP
02650       void *perf = NpfBeginInterval();
02651 
02652       TrainTrackFollowerData fd;
02653       FillWithStationData(&fd, v);
02654 
02655       /* New train pathfinding */
02656       fd.best_bird_dist = UINT_MAX;
02657       fd.best_track_dist = UINT_MAX;
02658       fd.best_track = INVALID_TRACKDIR;
02659 
02660       NewTrainPathfind(tile - TileOffsByDiagDir(enterdir), v->dest_tile,
02661         v->u.rail.compatible_railtypes, enterdir, (NTPEnumProc*)NtpCallbFindStation, &fd);
02662 
02663       /* check whether the path was found or only 'guessed' */
02664       if (fd.best_bird_dist != 0 && path_not_found != NULL) *path_not_found = true;
02665 
02666       if (fd.best_track == INVALID_TRACKDIR) {
02667         /* blaha */
02668         best_track = FindFirstTrack(tracks);
02669       } else {
02670         best_track = TrackdirToTrack(fd.best_track);
02671       }
02672 
02673       int time = NpfEndInterval(perf);
02674       DEBUG(yapf, 4, "[NTPT] %d us - %d rounds - %d open - %d closed -- ", time, 0, 0, 0);
02675     } break;
02676   }
02677 
02678 #ifdef PF_BENCHMARK
02679   TOC("PF time = ", 1)
02680 #endif
02681 
02682   return best_track;
02683 }
02684 
02690 static PBSTileInfo ExtendTrainReservation(const Vehicle *v, TrackBits *new_tracks, DiagDirection *enterdir)
02691 {
02692   bool no_90deg_turns = _settings_game.pf.pathfinder_for_trains != VPF_NTP && _settings_game.pf.forbid_90_deg;
02693   PBSTileInfo origin = FollowTrainReservation(v);
02694 
02695   CFollowTrackRail ft(v);
02696 
02697   TileIndex tile = origin.tile;
02698   Trackdir  cur_td = origin.trackdir;
02699   while (ft.Follow(tile, cur_td)) {
02700     if (KillFirstBit(ft.m_new_td_bits) == TRACKDIR_BIT_NONE) {
02701       /* Possible signal tile. */
02702       if (HasOnewaySignalBlockingTrackdir(ft.m_new_tile, FindFirstTrackdir(ft.m_new_td_bits))) break;
02703     }
02704 
02705     if (no_90deg_turns) {
02706       ft.m_new_td_bits &= ~TrackdirCrossesTrackdirs(ft.m_old_td);
02707       if (ft.m_new_td_bits == TRACKDIR_BIT_NONE) break;
02708     }
02709 
02710     /* Station, depot or waypoint are a possible target. */
02711     bool target_seen = ft.m_is_station || (IsTileType(ft.m_new_tile, MP_RAILWAY) && !IsPlainRailTile(ft.m_new_tile));
02712     if (target_seen || KillFirstBit(ft.m_new_td_bits) != TRACKDIR_BIT_NONE) {
02713       /* Choice found or possible target encountered.
02714        * On finding a possible target, we need to stop and let the pathfinder handle the
02715        * remaining path. This is because we don't know if this target is in one of our
02716        * orders, so we might cause pathfinding to fail later on if we find a choice.
02717        * This failure would cause a bogous call to TryReserveSafePath which might reserve
02718        * a wrong path not leading to our next destination. */
02719       if (HasReservedTracks(ft.m_new_tile, TrackdirBitsToTrackBits(TrackdirReachesTrackdirs(ft.m_old_td)))) break;
02720 
02721       /* If we did skip some tiles, backtrack to the first skipped tile so the pathfinder
02722        * actually starts its search at the first unreserved tile. */
02723       if (ft.m_tiles_skipped != 0) ft.m_new_tile -= TileOffsByDiagDir(ft.m_exitdir) * ft.m_tiles_skipped;
02724 
02725       /* Choice found, path valid but not okay. Save info about the choice tile as well. */
02726       if (new_tracks) *new_tracks = TrackdirBitsToTrackBits(ft.m_new_td_bits);
02727       if (enterdir) *enterdir = ft.m_exitdir;
02728       return PBSTileInfo(ft.m_new_tile, ft.m_old_td, false);
02729     }
02730 
02731     tile = ft.m_new_tile;
02732     cur_td = FindFirstTrackdir(ft.m_new_td_bits);
02733 
02734     if (IsSafeWaitingPosition(v, tile, cur_td, true, no_90deg_turns)) {
02735       bool wp_free = IsWaitingPositionFree(v, tile, cur_td, no_90deg_turns);
02736       if (!(wp_free && TryReserveRailTrack(tile, TrackdirToTrack(cur_td)))) break;
02737       /* Safe position is all good, path valid and okay. */
02738       return PBSTileInfo(tile, cur_td, true);
02739     }
02740 
02741     if (!TryReserveRailTrack(tile, TrackdirToTrack(cur_td))) break;
02742   }
02743 
02744   if (ft.m_err == CFollowTrackRail::EC_OWNER || ft.m_err == CFollowTrackRail::EC_NO_WAY) {
02745     /* End of line, path valid and okay. */
02746     return PBSTileInfo(ft.m_old_tile, ft.m_old_td, true);
02747   }
02748 
02749   /* Sorry, can't reserve path, back out. */
02750   tile = origin.tile;
02751   cur_td = origin.trackdir;
02752   TileIndex stopped = ft.m_old_tile;
02753   Trackdir  stopped_td = ft.m_old_td;
02754   while (tile != stopped || cur_td != stopped_td) {
02755     if (!ft.Follow(tile, cur_td)) break;
02756 
02757     if (no_90deg_turns) {
02758       ft.m_new_td_bits &= ~TrackdirCrossesTrackdirs(ft.m_old_td);
02759       assert(ft.m_new_td_bits != TRACKDIR_BIT_NONE);
02760     }
02761     assert(KillFirstBit(ft.m_new_td_bits) == TRACKDIR_BIT_NONE);
02762 
02763     tile = ft.m_new_tile;
02764     cur_td = FindFirstTrackdir(ft.m_new_td_bits);
02765 
02766     UnreserveRailTrack(tile, TrackdirToTrack(cur_td));
02767   }
02768 
02769   /* Path invalid. */
02770   return PBSTileInfo();
02771 }
02772 
02783 static bool TryReserveSafeTrack(const Vehicle *v, TileIndex tile, Trackdir td, bool override_tailtype)
02784 {
02785   if (_settings_game.pf.pathfinder_for_trains == VPF_YAPF) {
02786     return YapfRailFindNearestSafeTile(v, tile, td, override_tailtype);
02787   } else {
02788     return NPFRouteToSafeTile(v, tile, td, override_tailtype).res_okay;
02789   }
02790 }
02791 
02793 class VehicleOrderSaver
02794 {
02795 private:
02796   Vehicle        *v;
02797   Order          old_order;
02798   TileIndex      old_dest_tile;
02799   StationID      old_last_station_visited;
02800   VehicleOrderID index;
02801 
02802 public:
02803   VehicleOrderSaver(Vehicle *_v) :
02804     v(_v),
02805     old_order(_v->current_order),
02806     old_dest_tile(_v->dest_tile),
02807     old_last_station_visited(_v->last_station_visited),
02808     index(_v->cur_order_index)
02809   {
02810   }
02811 
02812   ~VehicleOrderSaver()
02813   {
02814     this->v->current_order = this->old_order;
02815     this->v->dest_tile = this->old_dest_tile;
02816     this->v->last_station_visited = this->old_last_station_visited;
02817   }
02818 
02824   bool SwitchToNextOrder(bool skip_first)
02825   {
02826     if (this->v->GetNumOrders() == 0) return false;
02827 
02828     if (skip_first) ++this->index;
02829 
02830     int conditional_depth = 0;
02831 
02832     do {
02833       /* Wrap around. */
02834       if (this->index >= this->v->GetNumOrders()) this->index = 0;
02835 
02836       Order *order = GetVehicleOrder(this->v, this->index);
02837       assert(order != NULL);
02838 
02839       switch (order->GetType()) {
02840         case OT_GOTO_DEPOT:
02841           /* Skip service in depot orders when the train doesn't need service. */
02842           if ((order->GetDepotOrderType() & ODTFB_SERVICE) && !this->v->NeedsServicing()) break;
02843         case OT_GOTO_STATION:
02844         case OT_GOTO_WAYPOINT:
02845           this->v->current_order = *order;
02846           UpdateOrderDest(this->v, order);
02847           return true;
02848         case OT_CONDITIONAL: {
02849           if (conditional_depth > this->v->GetNumOrders()) return false;
02850           VehicleOrderID next = ProcessConditionalOrder(order, this->v);
02851           if (next != INVALID_VEH_ORDER_ID) {
02852             conditional_depth++;
02853             this->index = next;
02854             /* Don't increment next, so no break here. */
02855             continue;
02856           }
02857           break;
02858         }
02859         default:
02860           break;
02861       }
02862       /* Don't increment inside the while because otherwise conditional
02863        * orders can lead to an infinite loop. */
02864       ++this->index;
02865     } while (this->index != this->v->cur_order_index);
02866 
02867     return false;
02868   }
02869 };
02870 
02871 /* choose a track */
02872 static Track ChooseTrainTrack(Vehicle *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks, bool force_res, bool *got_reservation, bool mark_stuck)
02873 {
02874   Track best_track = INVALID_TRACK;
02875   bool do_track_reservation = _settings_game.pf.reserve_paths || force_res;
02876   bool changed_signal = false;
02877 
02878   assert((tracks & ~TRACK_BIT_MASK) == 0);
02879 
02880   if (got_reservation != NULL) *got_reservation = false;
02881 
02882   /* Don't use tracks here as the setting to forbid 90 deg turns might have been switched between reservation and now. */
02883   TrackBits res_tracks = (TrackBits)(GetReservedTrackbits(tile) & DiagdirReachesTracks(enterdir));
02884   /* Do we have a suitable reserved track? */
02885   if (res_tracks != TRACK_BIT_NONE) return FindFirstTrack(res_tracks);
02886 
02887   /* Quick return in case only one possible track is available */
02888   if (KillFirstBit(tracks) == TRACK_BIT_NONE) {
02889     Track track = FindFirstTrack(tracks);
02890     /* We need to check for signals only here, as a junction tile can't have signals. */
02891     if (track != INVALID_TRACK && HasPbsSignalOnTrackdir(tile, TrackEnterdirToTrackdir(track, enterdir))) {
02892       do_track_reservation = true;
02893       changed_signal = true;
02894       SetSignalStateByTrackdir(tile, TrackEnterdirToTrackdir(track, enterdir), SIGNAL_STATE_GREEN);
02895     } else if (!do_track_reservation) {
02896       return track;
02897     }
02898     best_track = track;
02899   }
02900 
02901   PBSTileInfo   res_dest(tile, INVALID_TRACKDIR, false);
02902   DiagDirection dest_enterdir = enterdir;
02903   if (do_track_reservation) {
02904     /* Check if the train needs service here, so it has a chance to always find a depot.
02905      * Also check if the current order is a service order so we don't reserve a path to
02906      * the destination but instead to the next one if service isn't needed. */
02907     CheckIfTrainNeedsService(v);
02908     if (v->current_order.IsType(OT_DUMMY) || v->current_order.IsType(OT_CONDITIONAL) || v->current_order.IsType(OT_GOTO_DEPOT)) ProcessOrders(v);
02909 
02910     res_dest = ExtendTrainReservation(v, &tracks, &dest_enterdir);
02911     if (res_dest.tile == INVALID_TILE) {
02912       /* Reservation failed? */
02913       if (mark_stuck) MarkTrainAsStuck(v);
02914       if (changed_signal) SetSignalStateByTrackdir(tile, TrackEnterdirToTrackdir(best_track, enterdir), SIGNAL_STATE_RED);
02915       return FindFirstTrack(tracks);
02916     }
02917   }
02918 
02919   /* Save the current train order. The destructor will restore the old order on function exit. */
02920   VehicleOrderSaver orders(v);
02921 
02922   /* If the current tile is the destination of the current order and
02923    * a reservation was requested, advance to the next order.
02924    * Don't advance on a depot order as depots are always safe end points
02925    * for a path and no look-ahead is necessary. This also avoids a
02926    * problem with depot orders not part of the order list when the
02927    * order list itself is empty. */
02928   if (v->current_order.IsType(OT_LEAVESTATION)) {
02929     orders.SwitchToNextOrder(false);
02930   } else if (v->current_order.IsType(OT_LOADING) || (!v->current_order.IsType(OT_GOTO_DEPOT) && (
02931       v->current_order.IsType(OT_GOTO_STATION) ?
02932       IsRailwayStationTile(v->tile) && v->current_order.GetDestination() == GetStationIndex(v->tile) :
02933       v->tile == v->dest_tile))) {
02934     orders.SwitchToNextOrder(true);
02935   }
02936 
02937   if (res_dest.tile != INVALID_TILE && !res_dest.okay) {
02938     /* Pathfinders are able to tell that route was only 'guessed'. */
02939     bool      path_not_found = false;
02940     TileIndex new_tile = res_dest.tile;
02941 
02942     Track next_track = DoTrainPathfind(v, new_tile, dest_enterdir, tracks, &path_not_found, do_track_reservation, &res_dest);
02943     if (new_tile == tile) best_track = next_track;
02944 
02945     /* handle "path not found" state */
02946     if (path_not_found) {
02947       /* PF didn't find the route */
02948       if (!HasBit(v->u.rail.flags, VRF_NO_PATH_TO_DESTINATION)) {
02949         /* it is first time the problem occurred, set the "path not found" flag */
02950         SetBit(v->u.rail.flags, VRF_NO_PATH_TO_DESTINATION);
02951         /* and notify user about the event */
02952         AI::NewEvent(v->owner, new AIEventVehicleLost(v->index));
02953         if (_settings_client.gui.lost_train_warn && v->owner == _local_company) {
02954           SetDParam(0, v->index);
02955           AddNewsItem(
02956             STR_TRAIN_IS_LOST,
02957             NS_ADVICE,
02958             v->index,
02959             0);
02960         }
02961       }
02962     } else {
02963       /* route found, is the train marked with "path not found" flag? */
02964       if (HasBit(v->u.rail.flags, VRF_NO_PATH_TO_DESTINATION)) {
02965         /* clear the flag as the PF's problem was solved */
02966         ClrBit(v->u.rail.flags, VRF_NO_PATH_TO_DESTINATION);
02967         /* can we also delete the "News" item somehow? */
02968       }
02969     }
02970   }
02971 
02972   /* No track reservation requested -> finished. */
02973   if (!do_track_reservation) return best_track;
02974 
02975   /* A path was found, but could not be reserved. */
02976   if (res_dest.tile != INVALID_TILE && !res_dest.okay) {
02977     if (mark_stuck) MarkTrainAsStuck(v);
02978     FreeTrainTrackReservation(v);
02979     return best_track;
02980   }
02981 
02982   /* No possible reservation target found, we are probably lost. */
02983   if (res_dest.tile == INVALID_TILE) {
02984     /* Try to find any safe destination. */
02985     PBSTileInfo origin = FollowTrainReservation(v);
02986     if (TryReserveSafeTrack(v, origin.tile, origin.trackdir, false)) {
02987       TrackBits res = GetReservedTrackbits(tile) & DiagdirReachesTracks(enterdir);
02988       best_track = FindFirstTrack(res);
02989       TryReserveRailTrack(v->tile, TrackdirToTrack(GetVehicleTrackdir(v)));
02990       if (got_reservation != NULL) *got_reservation = true;
02991       if (changed_signal) MarkTileDirtyByTile(tile);
02992     } else {
02993       FreeTrainTrackReservation(v);
02994       if (mark_stuck) MarkTrainAsStuck(v);
02995     }
02996     return best_track;
02997   }
02998 
02999   if (got_reservation != NULL) *got_reservation = true;
03000 
03001   /* Reservation target found and free, check if it is safe. */
03002   while (!IsSafeWaitingPosition(v, res_dest.tile, res_dest.trackdir, true, _settings_game.pf.forbid_90_deg)) {
03003     /* Extend reservation until we have found a safe position. */
03004     DiagDirection exitdir = TrackdirToExitdir(res_dest.trackdir);
03005     TileIndex     next_tile = TileAddByDiagDir(res_dest.tile, exitdir);
03006     TrackBits     reachable = TrackdirBitsToTrackBits((TrackdirBits)(GetTileTrackStatus(next_tile, TRANSPORT_RAIL, 0))) & DiagdirReachesTracks(exitdir);
03007     if (_settings_game.pf.pathfinder_for_trains != VPF_NTP && _settings_game.pf.forbid_90_deg) {
03008       reachable &= ~TrackCrossesTracks(TrackdirToTrack(res_dest.trackdir));
03009     }
03010 
03011     /* Get next order with destination. */
03012     if (orders.SwitchToNextOrder(true)) {
03013       PBSTileInfo cur_dest;
03014       DoTrainPathfind(v, next_tile, exitdir, reachable, NULL, true, &cur_dest);
03015       if (cur_dest.tile != INVALID_TILE) {
03016         res_dest = cur_dest;
03017         if (res_dest.okay) continue;
03018         /* Path found, but could not be reserved. */
03019         FreeTrainTrackReservation(v);
03020         if (mark_stuck) MarkTrainAsStuck(v);
03021         if (got_reservation != NULL) *got_reservation = false;
03022         changed_signal = false;
03023         break;
03024       }
03025     }
03026     /* No order or no safe position found, try any position. */
03027     if (!TryReserveSafeTrack(v, res_dest.tile, res_dest.trackdir, true)) {
03028       FreeTrainTrackReservation(v);
03029       if (mark_stuck) MarkTrainAsStuck(v);
03030       if (got_reservation != NULL) *got_reservation = false;
03031       changed_signal = false;
03032     }
03033     break;
03034   }
03035 
03036   TryReserveRailTrack(v->tile, TrackdirToTrack(GetVehicleTrackdir(v)));
03037 
03038   if (changed_signal) MarkTileDirtyByTile(tile);
03039 
03040   return best_track;
03041 }
03042 
03051 bool TryPathReserve(Vehicle *v, bool mark_as_stuck, bool first_tile_okay)
03052 {
03053   assert(v->type == VEH_TRAIN && IsFrontEngine(v));
03054 
03055   /* We have to handle depots specially as the track follower won't look
03056    * at the depot tile itself but starts from the next tile. If we are still
03057    * inside the depot, a depot reservation can never be ours. */
03058   if (v->u.rail.track & TRACK_BIT_DEPOT) {
03059     if (GetDepotWaypointReservation(v->tile)) {
03060       if (mark_as_stuck) MarkTrainAsStuck(v);
03061       return false;
03062     } else {
03063       /* Depot not reserved, but the next tile might be. */
03064       TileIndex next_tile = TileAddByDiagDir(v->tile, GetRailDepotDirection(v->tile));
03065       if (HasReservedTracks(next_tile, DiagdirReachesTracks(GetRailDepotDirection(v->tile)))) return false;
03066     }
03067   }
03068 
03069   /* Special check if we are in front of a two-sided conventional signal. */
03070   DiagDirection dir = TrainExitDir(v->direction, v->u.rail.track);
03071   TileIndex next_tile = TileAddByDiagDir(v->tile, dir);
03072   if (IsTileType(next_tile, MP_RAILWAY) && HasReservedTracks(next_tile, DiagdirReachesTracks(dir))) {
03073     /* Can have only one reserved trackdir. */
03074     Trackdir td = FindFirstTrackdir(TrackBitsToTrackdirBits(GetReservedTrackbits(next_tile)) & DiagdirReachesTrackdirs(dir));
03075     if (HasSignalOnTrackdir(next_tile, td) && HasSignalOnTrackdir(next_tile, ReverseTrackdir(td)) &&
03076         !IsPbsSignal(GetSignalType(next_tile, TrackdirToTrack(td)))) {
03077       /* Signal already reserved, is not ours. */
03078       if (mark_as_stuck) MarkTrainAsStuck(v);
03079       return false;
03080     }
03081   }
03082 
03083   bool other_train = false;
03084   PBSTileInfo origin = FollowTrainReservation(v, &other_train);
03085   /* If we have a reserved path and the path ends at a safe tile, we are finished already. */
03086   if (origin.okay && (v->tile != origin.tile || first_tile_okay)) {
03087     /* Can't be stuck then. */
03088     if (HasBit(v->u.rail.flags, VRF_TRAIN_STUCK)) InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
03089     ClrBit(v->u.rail.flags, VRF_TRAIN_STUCK);
03090     return true;
03091   }
03092   /* The path we are driving on is alread blocked by some other train.
03093    * This can only happen when tracks and signals are changed. A crash
03094    * is probably imminent, don't do any further reservation because
03095    * it might cause stale reservations. */
03096   if (other_train && v->tile != origin.tile) {
03097     if (mark_as_stuck) MarkTrainAsStuck(v);
03098     return false;
03099   }
03100 
03101   /* If we are in a depot, tentativly reserve the depot. */
03102   if (v->u.rail.track & TRACK_BIT_DEPOT) {
03103     SetDepotWaypointReservation(v->tile, true);
03104     if (_settings_client.gui.show_track_reservation) MarkTileDirtyByTile(v->tile);
03105   }
03106 
03107   DiagDirection exitdir = TrackdirToExitdir(origin.trackdir);
03108   TileIndex     new_tile = TileAddByDiagDir(origin.tile, exitdir);
03109   TrackBits     reachable = TrackdirBitsToTrackBits(TrackStatusToTrackdirBits(GetTileTrackStatus(new_tile, TRANSPORT_RAIL, 0)) & DiagdirReachesTrackdirs(exitdir));
03110 
03111   if (_settings_game.pf.pathfinder_for_trains != VPF_NTP && _settings_game.pf.forbid_90_deg) reachable &= ~TrackCrossesTracks(TrackdirToTrack(origin.trackdir));
03112 
03113   bool res_made = false;
03114   ChooseTrainTrack(v, new_tile, exitdir, reachable, true, &res_made, mark_as_stuck);
03115 
03116   if (!res_made) {
03117     /* Free the depot reservation as well. */
03118     if (v->u.rail.track & TRACK_BIT_DEPOT) SetDepotWaypointReservation(v->tile, false);
03119     return false;
03120   }
03121 
03122   if (HasBit(v->u.rail.flags, VRF_TRAIN_STUCK)) {
03123     v->load_unload_time_rem = 0;
03124     InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
03125   }
03126   ClrBit(v->u.rail.flags, VRF_TRAIN_STUCK);
03127   return true;
03128 }
03129 
03130 
03131 static bool CheckReverseTrain(Vehicle *v)
03132 {
03133   if (_settings_game.difficulty.line_reverse_mode != 0 ||
03134       v->u.rail.track == TRACK_BIT_DEPOT || v->u.rail.track == TRACK_BIT_WORMHOLE ||
03135       !(v->direction & 1)) {
03136     return false;
03137   }
03138 
03139   uint reverse_best = 0;
03140 
03141   assert(v->u.rail.track);
03142 
03143   switch (_settings_game.pf.pathfinder_for_trains) {
03144     case VPF_YAPF: // YAPF
03145       reverse_best = YapfCheckReverseTrain(v);
03146       break;
03147 
03148     case VPF_NPF: { // NPF
03149       NPFFindStationOrTileData fstd;
03150       NPFFoundTargetData ftd;
03151       Vehicle *last = GetLastVehicleInChain(v);
03152 
03153       NPFFillWithOrderData(&fstd, v);
03154 
03155       Trackdir trackdir = GetVehicleTrackdir(v);
03156       Trackdir trackdir_rev = ReverseTrackdir(GetVehicleTrackdir(last));
03157       assert(trackdir != INVALID_TRACKDIR);
03158       assert(trackdir_rev != INVALID_TRACKDIR);
03159 
03160       ftd = NPFRouteToStationOrTileTwoWay(v->tile, trackdir, false, last->tile, trackdir_rev, false, &fstd, TRANSPORT_RAIL, 0, v->owner, v->u.rail.compatible_railtypes);
03161       if (ftd.best_bird_dist != 0) {
03162         /* We didn't find anything, just keep on going straight ahead */
03163         reverse_best = false;
03164       } else {
03165         if (NPFGetFlag(&ftd.node, NPF_FLAG_REVERSE)) {
03166           reverse_best = true;
03167         } else {
03168           reverse_best = false;
03169         }
03170       }
03171     } break;
03172 
03173     default:
03174     case VPF_NTP: { // NTP
03175       TrainTrackFollowerData fd;
03176       FillWithStationData(&fd, v);
03177 
03178       int i = _search_directions[FindFirstTrack(v->u.rail.track)][DirToDiagDir(v->direction)];
03179 
03180       int best_track = -1;
03181       uint reverse = 0;
03182       uint best_bird_dist  = 0;
03183       uint best_track_dist = 0;
03184 
03185       for (;;) {
03186         fd.best_bird_dist = UINT_MAX;
03187         fd.best_track_dist = UINT_MAX;
03188 
03189         NewTrainPathfind(v->tile, v->dest_tile, v->u.rail.compatible_railtypes, (DiagDirection)(reverse ^ i), (NTPEnumProc*)NtpCallbFindStation, &fd);
03190 
03191         if (best_track != -1) {
03192           if (best_bird_dist != 0) {
03193             if (fd.best_bird_dist != 0) {
03194               /* neither reached the destination, pick the one with the smallest bird dist */
03195               if (fd.best_bird_dist > best_bird_dist) goto bad;
03196               if (fd.best_bird_dist < best_bird_dist) goto good;
03197             } else {
03198               /* we found the destination for the first time */
03199               goto good;
03200             }
03201           } else {
03202             if (fd.best_bird_dist != 0) {
03203               /* didn't find destination, but we've found the destination previously */
03204               goto bad;
03205             } else {
03206               /* both old & new reached the destination, compare track length */
03207               if (fd.best_track_dist > best_track_dist) goto bad;
03208               if (fd.best_track_dist < best_track_dist) goto good;
03209             }
03210           }
03211 
03212           /* if we reach this position, there's two paths of equal value so far.
03213            * pick one randomly. */
03214           int r = GB(Random(), 0, 8);
03215           if (_pick_track_table[i] == (v->direction & 3)) r += 80;
03216           if (_pick_track_table[best_track] == (v->direction & 3)) r -= 80;
03217           if (r <= 127) goto bad;
03218         }
03219 good:;
03220         best_track = i;
03221         best_bird_dist = fd.best_bird_dist;
03222         best_track_dist = fd.best_track_dist;
03223         reverse_best = reverse;
03224 bad:;
03225         if (reverse != 0) break;
03226         reverse = 2;
03227       }
03228     } break;
03229   }
03230 
03231   return reverse_best != 0;
03232 }
03233 
03234 TileIndex Train::GetOrderStationLocation(StationID station)
03235 {
03236   if (station == this->last_station_visited) this->last_station_visited = INVALID_STATION;
03237 
03238   const Station *st = GetStation(station);
03239   if (!(st->facilities & FACIL_TRAIN)) {
03240     /* The destination station has no trainstation tiles. */
03241     this->cur_order_index++;
03242     return 0;
03243   }
03244 
03245   return st->xy;
03246 }
03247 
03248 void Train::MarkDirty()
03249 {
03250   Vehicle *v = this;
03251   do {
03252     v->cur_image = v->GetImage(v->direction);
03253     MarkSingleVehicleDirty(v);
03254   } while ((v = v->Next()) != NULL);
03255 
03256   /* need to update acceleration and cached values since the goods on the train changed. */
03257   TrainCargoChanged(this);
03258   UpdateTrainAcceleration(this);
03259 }
03260 
03271 static int UpdateTrainSpeed(Vehicle *v)
03272 {
03273   uint accel;
03274 
03275   if (v->vehstatus & VS_STOPPED || HasBit(v->u.rail.flags, VRF_REVERSING) || HasBit(v->u.rail.flags, VRF_TRAIN_STUCK)) {
03276     switch (_settings_game.vehicle.train_acceleration_model) {
03277       default: NOT_REACHED();
03278       case TAM_ORIGINAL:  accel = v->acceleration * -4; break;
03279       case TAM_REALISTIC: accel = GetTrainAcceleration(v, AM_BRAKE); break;
03280     }
03281   } else {
03282     switch (_settings_game.vehicle.train_acceleration_model) {
03283       default: NOT_REACHED();
03284       case TAM_ORIGINAL:  accel = v->acceleration * 2; break;
03285       case TAM_REALISTIC: accel = GetTrainAcceleration(v, AM_ACCEL); break;
03286     }
03287   }
03288 
03289   uint spd = v->subspeed + accel;
03290   v->subspeed = (byte)spd;
03291   {
03292     int tempmax = v->max_speed;
03293     if (v->cur_speed > v->max_speed)
03294       tempmax = v->cur_speed - (v->cur_speed / 10) - 1;
03295     v->cur_speed = spd = Clamp(v->cur_speed + ((int)spd >> 8), 0, tempmax);
03296   }
03297 
03298   /* Scale speed by 3/4. Previously this was only done when the train was
03299    * facing diagonally and would apply to however many moves the train made
03300    * regardless the of direction actually moved in. Now it is always scaled,
03301    * 256 spd is used to go straight and 192 is used to go diagonally
03302    * (3/4 of 256). This results in the same effect, but without the error the
03303    * previous method caused.
03304    *
03305    * The scaling is done in this direction and not by multiplying the amount
03306    * to be subtracted by 4/3 so that the leftover speed can be saved in a
03307    * byte in v->progress.
03308    */
03309   int scaled_spd = spd * 3 >> 2;
03310 
03311   scaled_spd += v->progress;
03312   v->progress = 0; // set later in TrainLocoHandler or TrainController
03313   return scaled_spd;
03314 }
03315 
03316 static void TrainEnterStation(Vehicle *v, StationID station)
03317 {
03318   v->last_station_visited = station;
03319 
03320   /* check if a train ever visited this station before */
03321   Station *st = GetStation(station);
03322   if (!(st->had_vehicle_of_type & HVOT_TRAIN)) {
03323     st->had_vehicle_of_type |= HVOT_TRAIN;
03324     SetDParam(0, st->index);
03325     AddNewsItem(
03326       STR_8801_CITIZENS_CELEBRATE_FIRST,
03327       v->owner == _local_company ? NS_ARRIVAL_COMPANY : NS_ARRIVAL_OTHER,
03328       v->index,
03329       st->index
03330     );
03331     AI::NewEvent(v->owner, new AIEventStationFirstVehicle(st->index, v->index));
03332   }
03333 
03334   v->BeginLoading();
03335 
03336   StationAnimationTrigger(st, v->tile, STAT_ANIM_TRAIN_ARRIVES);
03337 }
03338 
03339 static byte AfterSetTrainPos(Vehicle *v, bool new_tile)
03340 {
03341   byte old_z = v->z_pos;
03342   v->z_pos = GetSlopeZ(v->x_pos, v->y_pos);
03343 
03344   if (new_tile) {
03345     ClrBit(v->u.rail.flags, VRF_GOINGUP);
03346     ClrBit(v->u.rail.flags, VRF_GOINGDOWN);
03347 
03348     if (v->u.rail.track == TRACK_BIT_X || v->u.rail.track == TRACK_BIT_Y) {
03349       /* Any track that isn't TRACK_BIT_X or TRACK_BIT_Y cannot be sloped.
03350        * To check whether the current tile is sloped, and in which
03351        * direction it is sloped, we get the 'z' at the center of
03352        * the tile (middle_z) and the edge of the tile (old_z),
03353        * which we then can compare. */
03354       static const int HALF_TILE_SIZE = TILE_SIZE / 2;
03355       static const int INV_TILE_SIZE_MASK = ~(TILE_SIZE - 1);
03356 
03357       byte middle_z = GetSlopeZ((v->x_pos & INV_TILE_SIZE_MASK) | HALF_TILE_SIZE, (v->y_pos & INV_TILE_SIZE_MASK) | HALF_TILE_SIZE);
03358 
03359       /* For some reason tunnel tiles are always given as sloped :(
03360        * But they are not sloped... */
03361       if (middle_z != v->z_pos && !IsTunnelTile(TileVirtXY(v->x_pos, v->y_pos))) {
03362         SetBit(v->u.rail.flags, (middle_z > old_z) ? VRF_GOINGUP : VRF_GOINGDOWN);
03363       }
03364     }
03365   }
03366 
03367   VehicleMove(v, true);
03368   return old_z;
03369 }
03370 
03371 static const Direction _new_vehicle_direction_table[11] = {
03372   DIR_N , DIR_NW, DIR_W , INVALID_DIR,
03373   DIR_NE, DIR_N , DIR_SW, INVALID_DIR,
03374   DIR_E , DIR_SE, DIR_S
03375 };
03376 
03377 static inline Direction GetNewVehicleDirectionByTile(TileIndex new_tile, TileIndex old_tile)
03378 {
03379   uint offs = (TileY(new_tile) - TileY(old_tile) + 1) * 4 +
03380               TileX(new_tile) - TileX(old_tile) + 1;
03381   assert(offs < 11);
03382   return _new_vehicle_direction_table[offs];
03383 }
03384 
03385 static inline int GetDirectionToVehicle(const Vehicle *v, int x, int y)
03386 {
03387   byte offs;
03388 
03389   x -= v->x_pos;
03390   if (x >= 0) {
03391     offs = (x > 2) ? 0 : 1;
03392   } else {
03393     offs = (x < -2) ? 2 : 1;
03394   }
03395 
03396   y -= v->y_pos;
03397   if (y >= 0) {
03398     offs += ((y > 2) ? 0 : 1) * 4;
03399   } else {
03400     offs += ((y < -2) ? 2 : 1) * 4;
03401   }
03402 
03403   assert(offs < 11);
03404   return _new_vehicle_direction_table[offs];
03405 }
03406 
03407 /* Check if the vehicle is compatible with the specified tile */
03408 static inline bool CheckCompatibleRail(const Vehicle *v, TileIndex tile)
03409 {
03410   return
03411     IsTileOwner(tile, v->owner) && (
03412       !IsFrontEngine(v) ||
03413       HasBit(v->u.rail.compatible_railtypes, GetRailType(tile))
03414     );
03415 }
03416 
03417 struct RailtypeSlowdownParams {
03418   byte small_turn, large_turn;
03419   byte z_up; // fraction to remove when moving up
03420   byte z_down; // fraction to remove when moving down
03421 };
03422 
03423 static const RailtypeSlowdownParams _railtype_slowdown[] = {
03424   /* normal accel */
03425   {256 / 4, 256 / 2, 256 / 4, 2}, 
03426   {256 / 4, 256 / 2, 256 / 4, 2}, 
03427   {256 / 4, 256 / 2, 256 / 4, 2}, 
03428   {0,       256 / 2, 256 / 4, 2}, 
03429 };
03430 
03432 static inline void AffectSpeedByDirChange(Vehicle *v, Direction new_dir)
03433 {
03434   if (_settings_game.vehicle.train_acceleration_model != TAM_ORIGINAL) return;
03435 
03436   DirDiff diff = DirDifference(v->direction, new_dir);
03437   if (diff == DIRDIFF_SAME) return;
03438 
03439   const RailtypeSlowdownParams *rsp = &_railtype_slowdown[v->u.rail.railtype];
03440   v->cur_speed -= (diff == DIRDIFF_45RIGHT || diff == DIRDIFF_45LEFT ? rsp->small_turn : rsp->large_turn) * v->cur_speed >> 8;
03441 }
03442 
03444 static inline void AffectSpeedByZChange(Vehicle *v, byte old_z)
03445 {
03446   if (old_z == v->z_pos || _settings_game.vehicle.train_acceleration_model != TAM_ORIGINAL) return;
03447 
03448   const RailtypeSlowdownParams *rsp = &_railtype_slowdown[v->u.rail.railtype];
03449 
03450   if (old_z < v->z_pos) {
03451     v->cur_speed -= (v->cur_speed * rsp->z_up >> 8);
03452   } else {
03453     uint16 spd = v->cur_speed + rsp->z_down;
03454     if (spd <= v->max_speed) v->cur_speed = spd;
03455   }
03456 }
03457 
03458 static bool TrainMovedChangeSignals(TileIndex tile, DiagDirection dir)
03459 {
03460   if (IsTileType(tile, MP_RAILWAY) &&
03461       GetRailTileType(tile) == RAIL_TILE_SIGNALS) {
03462     TrackdirBits tracks = TrackBitsToTrackdirBits(GetTrackBits(tile)) & DiagdirReachesTrackdirs(dir);
03463     Trackdir trackdir = FindFirstTrackdir(tracks);
03464     if (UpdateSignalsOnSegment(tile,  TrackdirToExitdir(trackdir), GetTileOwner(tile)) == SIGSEG_PBS && HasSignalOnTrackdir(tile, trackdir)) {
03465       /* A PBS block with a non-PBS signal facing us? */
03466       if (!IsPbsSignal(GetSignalType(tile, TrackdirToTrack(trackdir)))) return true;
03467     }
03468   }
03469   return false;
03470 }
03471 
03472 
03473 static void SetVehicleCrashed(Vehicle *v)
03474 {
03475   if (v->u.rail.crash_anim_pos != 0) return;
03476 
03477   /* Free a possible path reservation and try to mark all tiles occupied by the train reserved. */
03478   if (IsFrontEngine(v)) {
03479     /* Remove all reservations, also the ones currently under the train
03480      * and any railway station paltform reservation. */
03481     FreeTrainTrackReservation(v);
03482     for (const Vehicle *u = v; u != NULL; u = u->Next()) {
03483       ClearPathReservation(u, u->tile, GetVehicleTrackdir(u));
03484       if (IsTileType(u->tile, MP_TUNNELBRIDGE)) {
03485         /* ClearPathReservation will not free the wormhole exit
03486          * if the train has just entered the wormhole. */
03487         SetTunnelBridgeReservation(GetOtherTunnelBridgeEnd(u->tile), false);
03488       }
03489     }
03490   }
03491 
03492   /* we may need to update crossing we were approaching */
03493   TileIndex crossing = TrainApproachingCrossingTile(v);
03494 
03495   v->u.rail.crash_anim_pos++;
03496 
03497   InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
03498   InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
03499 
03500   if (v->u.rail.track == TRACK_BIT_DEPOT) {
03501     InvalidateWindow(WC_VEHICLE_DEPOT, v->tile);
03502   }
03503 
03504   InvalidateWindowClassesData(WC_TRAINS_LIST, 0);
03505 
03506   for (; v != NULL; v = v->Next()) {
03507     v->vehstatus |= VS_CRASHED;
03508     MarkSingleVehicleDirty(v);
03509   }
03510 
03511   /* must be updated after the train has been marked crashed */
03512   if (crossing != INVALID_TILE) UpdateLevelCrossing(crossing);
03513 }
03514 
03515 static uint CountPassengersInTrain(const Vehicle *v)
03516 {
03517   uint num = 0;
03518 
03519   for (; v != NULL; v = v->Next()) {
03520     if (IsCargoInClass(v->cargo_type, CC_PASSENGERS)) num += v->cargo.Count();
03521   }
03522 
03523   return num;
03524 }
03525 
03532 static uint TrainCrashed(Vehicle *v)
03533 {
03534   /* do not crash train twice */
03535   if (v->vehstatus & VS_CRASHED) return 0;
03536 
03537   /* two drivers + passengers */
03538   uint num = 2 + CountPassengersInTrain(v);
03539 
03540   SetVehicleCrashed(v);
03541   AI::NewEvent(v->owner, new AIEventVehicleCrashed(v->index, v->tile, AIEventVehicleCrashed::CRASH_TRAIN));
03542 
03543   return num;
03544 }
03545 
03546 struct TrainCollideChecker {
03547   Vehicle *v;  
03548   uint num;    
03549 };
03550 
03551 static Vehicle *FindTrainCollideEnum(Vehicle *v, void *data)
03552 {
03553   TrainCollideChecker *tcc = (TrainCollideChecker*)data;
03554 
03555   if (v->type != VEH_TRAIN) return NULL;
03556 
03557   /* get first vehicle now to make most usual checks faster */
03558   Vehicle *coll = v->First();
03559 
03560   /* can't collide with own wagons && can't crash in depot && the same height level */
03561   if (coll != tcc->v && v->u.rail.track != TRACK_BIT_DEPOT && abs(v->z_pos - tcc->v->z_pos) < 6) {
03562     int x_diff = v->x_pos - tcc->v->x_pos;
03563     int y_diff = v->y_pos - tcc->v->y_pos;
03564 
03565     /* needed to disable possible crash of competitor train in station by building diagonal track at its end */
03566     if (x_diff * x_diff + y_diff * y_diff > 25) return NULL;
03567 
03568     /* crash both trains */
03569     tcc->num += TrainCrashed(tcc->v);
03570     tcc->num += TrainCrashed(coll);
03571 
03572     /* Try to reserve all tiles directly under the crashed trains.
03573      * As there might be more than two trains involved, we have to do that for all vehicles */
03574     const Vehicle *u;
03575     FOR_ALL_VEHICLES(u) {
03576       if (u->type == VEH_TRAIN && HASBITS(u->vehstatus, VS_CRASHED) && (u->u.rail.track & TRACK_BIT_DEPOT) == TRACK_BIT_NONE) {
03577         TrackBits trackbits = u->u.rail.track;
03578         if ((trackbits & TRACK_BIT_WORMHOLE) == TRACK_BIT_WORMHOLE) {
03579           /* Vehicle is inside a wormhole, v->u.rail.track contains no useful value then. */
03580           trackbits |= DiagDirToDiagTrackBits(GetTunnelBridgeDirection(u->tile));
03581         }
03582         TryReserveRailTrack(u->tile, TrackBitsToTrack(trackbits));
03583       }
03584     }
03585   }
03586 
03587   return NULL;
03588 }
03589 
03596 static bool CheckTrainCollision(Vehicle *v)
03597 {
03598   /* can't collide in depot */
03599   if (v->u.rail.track == TRACK_BIT_DEPOT) return false;
03600 
03601   assert(v->u.rail.track == TRACK_BIT_WORMHOLE || TileVirtXY(v->x_pos, v->y_pos) == v->tile);
03602 
03603   TrainCollideChecker tcc;
03604   tcc.v = v;
03605   tcc.num = 0;
03606 
03607   /* find colliding vehicles */
03608   if (v->u.rail.track == TRACK_BIT_WORMHOLE) {
03609     FindVehicleOnPos(v->tile, &tcc, FindTrainCollideEnum);
03610     FindVehicleOnPos(GetOtherTunnelBridgeEnd(v->tile), &tcc, FindTrainCollideEnum);
03611   } else {
03612     FindVehicleOnPosXY(v->x_pos, v->y_pos, &tcc, FindTrainCollideEnum);
03613   }
03614 
03615   /* any dead -> no crash */
03616   if (tcc.num == 0) return false;
03617 
03618   SetDParam(0, tcc.num);
03619   AddNewsItem(STR_8868_TRAIN_CRASH_DIE_IN_FIREBALL,
03620     NS_ACCIDENT_VEHICLE,
03621     v->index,
03622     0
03623   );
03624 
03625   ModifyStationRatingAround(v->tile, v->owner, -160, 30);
03626   SndPlayVehicleFx(SND_13_BIG_CRASH, v);
03627   return true;
03628 }
03629 
03630 static Vehicle *CheckVehicleAtSignal(Vehicle *v, void *data)
03631 {
03632   DiagDirection exitdir = *(DiagDirection *)data;
03633 
03634   /* front engine of a train, not inside wormhole or depot, not crashed */
03635   if (v->type == VEH_TRAIN && IsFrontEngine(v) && (v->u.rail.track & TRACK_BIT_MASK) != 0 && !(v->vehstatus & VS_CRASHED)) {
03636     if (v->cur_speed <= 5 && TrainExitDir(v->direction, v->u.rail.track) == exitdir) return v;
03637   }
03638 
03639   return NULL;
03640 }
03641 
03642 static void TrainController(Vehicle *v, Vehicle *nomove)
03643 {
03644   Vehicle *prev;
03645 
03646   /* For every vehicle after and including the given vehicle */
03647   for (prev = v->Previous(); v != nomove; prev = v, v = v->Next()) {
03648     DiagDirection enterdir = DIAGDIR_BEGIN;
03649     bool update_signals_crossing = false; // will we update signals or crossing state?
03650 
03651     GetNewVehiclePosResult gp = GetNewVehiclePos(v);
03652     if (v->u.rail.track != TRACK_BIT_WORMHOLE) {
03653       /* Not inside tunnel */
03654       if (gp.old_tile == gp.new_tile) {
03655         /* Staying in the old tile */
03656         if (v->u.rail.track == TRACK_BIT_DEPOT) {
03657           /* Inside depot */
03658           gp.x = v->x_pos;
03659           gp.y = v->y_pos;
03660         } else {
03661           /* Not inside depot */
03662 
03663           /* Reverse when we are at the end of the track already, do not move to the new position */
03664           if (IsFrontEngine(v) && !TrainCheckIfLineEnds(v)) return;
03665 
03666           uint32 r = VehicleEnterTile(v, gp.new_tile, gp.x, gp.y);
03667           if (HasBit(r, VETS_CANNOT_ENTER)) {
03668             goto invalid_rail;
03669           }
03670           if (HasBit(r, VETS_ENTERED_STATION)) {
03671             /* The new position is the end of the platform */
03672             TrainEnterStation(v, r >> VETS_STATION_ID_OFFSET);
03673           }
03674         }
03675       } else {
03676         /* A new tile is about to be entered. */
03677 
03678         /* Determine what direction we're entering the new tile from */
03679         Direction dir = GetNewVehicleDirectionByTile(gp.new_tile, gp.old_tile);
03680         enterdir = DirToDiagDir(dir);
03681         assert(IsValidDiagDirection(enterdir));
03682 
03683         /* Get the status of the tracks in the new tile and mask
03684          * away the bits that aren't reachable. */
03685         TrackStatus ts = GetTileTrackStatus(gp.new_tile, TRANSPORT_RAIL, 0, ReverseDiagDir(enterdir));
03686         TrackdirBits reachable_trackdirs = DiagdirReachesTrackdirs(enterdir);
03687 
03688         TrackdirBits trackdirbits = TrackStatusToTrackdirBits(ts) & reachable_trackdirs;
03689         TrackBits red_signals = TrackdirBitsToTrackBits(TrackStatusToRedSignals(ts) & reachable_trackdirs);
03690 
03691         TrackBits bits = TrackdirBitsToTrackBits(trackdirbits);
03692         if (_settings_game.pf.pathfinder_for_trains != VPF_NTP && _settings_game.pf.forbid_90_deg && prev == NULL) {
03693           /* We allow wagons to make 90 deg turns, because forbid_90_deg
03694            * can be switched on halfway a turn */
03695           bits &= ~TrackCrossesTracks(FindFirstTrack(v->u.rail.track));
03696         }
03697 
03698         if (bits == TRACK_BIT_NONE) goto invalid_rail;
03699 
03700         /* Check if the new tile contrains tracks that are compatible
03701          * with the current train, if not, bail out. */
03702         if (!CheckCompatibleRail(v, gp.new_tile)) goto invalid_rail;
03703 
03704         TrackBits chosen_track;
03705         if (prev == NULL) {
03706           /* Currently the locomotive is active. Determine which one of the
03707            * available tracks to choose */
03708           chosen_track = TrackToTrackBits(ChooseTrainTrack(v, gp.new_tile, enterdir, bits, false, NULL, true));
03709           assert(chosen_track & (bits | GetReservedTrackbits(gp.new_tile)));
03710 
03711           /* Check if it's a red signal and that force proceed is not clicked. */
03712           if (red_signals & chosen_track && v->u.rail.force_proceed == 0) {
03713             /* In front of a red signal */
03714             Trackdir i = FindFirstTrackdir(trackdirbits);
03715 
03716             /* Don't handle stuck trains here. */
03717             if (HasBit(v->u.rail.flags, VRF_TRAIN_STUCK)) return;
03718 
03719             if (!HasSignalOnTrackdir(gp.new_tile, ReverseTrackdir(i))) {
03720               v->cur_speed = 0;
03721               v->subspeed = 0;
03722               v->progress = 255 - 100;
03723               if (_settings_game.pf.wait_oneway_signal == 255 || ++v->load_unload_time_rem < _settings_game.pf.wait_oneway_signal * 20) return;
03724             } else if (HasSignalOnTrackdir(gp.new_tile, i)) {
03725               v->cur_speed = 0;
03726               v->subspeed = 0;
03727               v->progress = 255 - 10;
03728               if (_settings_game.pf.wait_twoway_signal == 255 || ++v->load_unload_time_rem < _settings_game.pf.wait_twoway_signal * 73) {
03729                 DiagDirection exitdir = TrackdirToExitdir(i);
03730                 TileIndex o_tile = TileAddByDiagDir(gp.new_tile, exitdir);
03731 
03732                 exitdir = ReverseDiagDir(exitdir);
03733 
03734                 /* check if a train is waiting on the other side */
03735                 if (!HasVehicleOnPos(o_tile, &exitdir, &CheckVehicleAtSignal)) return;
03736               }
03737             }
03738 
03739             /* If we would reverse but are currently in a PBS block and
03740              * reversing of stuck trains is disabled, don't reverse. */
03741             if (_settings_game.pf.wait_for_pbs_path == 255 && UpdateSignalsOnSegment(v->tile, enterdir, v->owner) == SIGSEG_PBS) {
03742               v->load_unload_time_rem = 0;
03743               return;
03744             }
03745             goto reverse_train_direction;
03746           } else {
03747             TryReserveRailTrack(gp.new_tile, TrackBitsToTrack(chosen_track));
03748           }
03749         } else {
03750           static const TrackBits _matching_tracks[8] = {
03751               TRACK_BIT_LEFT  | TRACK_BIT_RIGHT, TRACK_BIT_X,
03752               TRACK_BIT_UPPER | TRACK_BIT_LOWER, TRACK_BIT_Y,
03753               TRACK_BIT_LEFT  | TRACK_BIT_RIGHT, TRACK_BIT_X,
03754               TRACK_BIT_UPPER | TRACK_BIT_LOWER, TRACK_BIT_Y
03755           };
03756 
03757           /* The wagon is active, simply follow the prev vehicle. */
03758           chosen_track = (TrackBits)(byte)(_matching_tracks[GetDirectionToVehicle(prev, gp.x, gp.y)] & bits);
03759         }
03760 
03761         /* Make sure chosen track is a valid track */
03762         assert(
03763             chosen_track == TRACK_BIT_X     || chosen_track == TRACK_BIT_Y ||
03764             chosen_track == TRACK_BIT_UPPER || chosen_track == TRACK_BIT_LOWER ||
03765             chosen_track == TRACK_BIT_LEFT  || chosen_track == TRACK_BIT_RIGHT);
03766 
03767         /* Update XY to reflect the entrance to the new tile, and select the direction to use */
03768         const byte *b = _initial_tile_subcoord[FIND_FIRST_BIT(chosen_track)][enterdir];
03769         gp.x = (gp.x & ~0xF) | b[0];
03770         gp.y = (gp.y & ~0xF) | b[1];
03771         Direction chosen_dir = (Direction)b[2];
03772 
03773         /* Call the landscape function and tell it that the vehicle entered the tile */
03774         uint32 r = VehicleEnterTile(v, gp.new_tile, gp.x, gp.y);
03775         if (HasBit(r, VETS_CANNOT_ENTER)) {
03776           goto invalid_rail;
03777         }
03778 
03779         if (!HasBit(r, VETS_ENTERED_WORMHOLE)) {
03780           Track track = FindFirstTrack(chosen_track);
03781           Trackdir tdir = TrackDirectionToTrackdir(track, chosen_dir);
03782           if (IsFrontEngine(v) && HasPbsSignalOnTrackdir(gp.new_tile, tdir)) {
03783             SetSignalStateByTrackdir(gp.new_tile, tdir, SIGNAL_STATE_RED);
03784             MarkTileDirtyByTile(gp.new_tile);
03785           }
03786 
03787           /* Clear any track reservation when the last vehicle leaves the tile */
03788           if (v->Next() == NULL) ClearPathReservation(v, v->tile, GetVehicleTrackdir(v));
03789 
03790           v->tile = gp.new_tile;
03791 
03792           if (GetTileRailType(gp.new_tile) != GetTileRailType(gp.old_tile)) {
03793             TrainPowerChanged(v->First());
03794           }
03795 
03796           v->u.rail.track = chosen_track;
03797           assert(v->u.rail.track);
03798         }
03799 
03800         /* We need to update signal status, but after the vehicle position hash
03801          * has been updated by AfterSetTrainPos() */
03802         update_signals_crossing = true;
03803 
03804         if (prev == NULL) AffectSpeedByDirChange(v, chosen_dir);
03805 
03806         v->direction = chosen_dir;
03807 
03808         if (IsFrontEngine(v)) {
03809           v->load_unload_time_rem = 0;
03810 
03811           /* If we are approching a crossing that is reserved, play the sound now. */
03812           TileIndex crossing = TrainApproachingCrossingTile(v);
03813           if (crossing != INVALID_TILE && GetCrossingReservation(crossing)) SndPlayTileFx(SND_0E_LEVEL_CROSSING, crossing);
03814 
03815           /* Always try to extend the reservation when entering a tile. */
03816           CheckNextTrainTile(v);
03817         }
03818       }
03819     } else {
03820       /* In a tunnel or on a bridge
03821        * - for tunnels, only the part when the vehicle is not visible (part of enter/exit tile too)
03822        * - for bridges, only the middle part - without the bridge heads */
03823       if (!(v->vehstatus & VS_HIDDEN)) {
03824         v->cur_speed =
03825           min(v->cur_speed, GetBridgeSpec(GetBridgeType(v->tile))->speed);
03826       }
03827 
03828       if (IsTileType(gp.new_tile, MP_TUNNELBRIDGE) && HasBit(VehicleEnterTile(v, gp.new_tile, gp.x, gp.y), VETS_ENTERED_WORMHOLE)) {
03829         /* Perform look-ahead on tunnel exit. */
03830         if (IsFrontEngine(v)) {
03831           TryReserveRailTrack(gp.new_tile, DiagDirToDiagTrack(GetTunnelBridgeDirection(gp.new_tile)));
03832           CheckNextTrainTile(v);
03833         }
03834       } else {
03835         v->x_pos = gp.x;
03836         v->y_pos = gp.y;
03837         VehicleMove(v, !(v->vehstatus & VS_HIDDEN));
03838         continue;
03839       }
03840     }
03841 
03842     /* update image of train, as well as delta XY */
03843     v->UpdateDeltaXY(v->direction);
03844 
03845     v->x_pos = gp.x;
03846     v->y_pos = gp.y;
03847 
03848     /* update the Z position of the vehicle */
03849     byte old_z = AfterSetTrainPos(v, (gp.new_tile != gp.old_tile));
03850 
03851     if (prev == NULL) {
03852       /* This is the first vehicle in the train */
03853       AffectSpeedByZChange(v, old_z);
03854     }
03855 
03856     if (update_signals_crossing) {
03857       if (IsFrontEngine(v)) {
03858         if (TrainMovedChangeSignals(gp.new_tile, enterdir)) {
03859           /* We are entering a block with PBS signals right now, but
03860            * not through a PBS signal. This means we don't have a
03861            * reservation right now. As a conventional signal will only
03862            * ever be green if no other train is in the block, getting
03863            * a path should always be possible. If the player built
03864            * such a strange network that it is not possible, the train
03865            * will be marked as stuck and the player has to deal with
03866            * the problem. */
03867           if ((!HasReservedTracks(gp.new_tile, v->u.rail.track) &&
03868               !TryReserveRailTrack(gp.new_tile, FindFirstTrack(v->u.rail.track))) ||
03869               !TryPathReserve(v)) {
03870             MarkTrainAsStuck(v);
03871           }
03872         }
03873       }
03874 
03875       /* Signals can only change when the first
03876        * (above) or the last vehicle moves. */
03877       if (v->Next() == NULL) {
03878         TrainMovedChangeSignals(gp.old_tile, ReverseDiagDir(enterdir));
03879         if (IsLevelCrossingTile(gp.old_tile)) UpdateLevelCrossing(gp.old_tile);
03880       }
03881     }
03882 
03883     /* Do not check on every tick to save some computing time. */
03884     if (IsFrontEngine(v) && v->tick_counter % _settings_game.pf.path_backoff_interval == 0) CheckNextTrainTile(v);
03885   }
03886   return;
03887 
03888 invalid_rail:
03889   /* We've reached end of line?? */
03890   if (prev != NULL) error("Disconnecting train");
03891 
03892 reverse_train_direction:
03893   v->load_unload_time_rem = 0;
03894   v->cur_speed = 0;
03895   v->subspeed = 0;
03896   ReverseTrainDirection(v);
03897 }
03898 
03904 static Vehicle *CollectTrackbitsFromCrashedVehiclesEnum(Vehicle *v, void *data)
03905 {
03906   TrackBits *trackbits = (TrackBits *)data;
03907 
03908   if (v->type == VEH_TRAIN && (v->vehstatus & VS_CRASHED) != 0) {
03909     if ((v->u.rail.track & TRACK_BIT_WORMHOLE) == TRACK_BIT_WORMHOLE) {
03910       /* Vehicle is inside a wormhole, v->u.rail.track contains no useful value then. */
03911       *trackbits |= DiagDirToDiagTrackBits(GetTunnelBridgeDirection(v->tile));
03912     } else {
03913       *trackbits |= v->u.rail.track;
03914     }
03915   }
03916 
03917   return NULL;
03918 }
03919 
03927 static void DeleteLastWagon(Vehicle *v)
03928 {
03929   Vehicle *first = v->First();
03930 
03931   /* Go to the last wagon and delete the link pointing there
03932    * *u is then the one-before-last wagon, and *v the last
03933    * one which will physicially be removed */
03934   Vehicle *u = v;
03935   for (; v->Next() != NULL; v = v->Next()) u = v;
03936   u->SetNext(NULL);
03937 
03938   if (first != v) {
03939     /* Recalculate cached train properties */
03940     TrainConsistChanged(first, false);
03941     /* Update the depot window if the first vehicle is in depot -
03942      * if v == first, then it is updated in PreDestructor() */
03943     if (first->u.rail.track == TRACK_BIT_DEPOT) {
03944       InvalidateWindow(WC_VEHICLE_DEPOT, first->tile);
03945     }
03946   }
03947 
03948   /* 'v' shouldn't be accessed after it has been deleted */
03949   TrackBits trackbits = v->u.rail.track;
03950   TileIndex tile = v->tile;
03951   Owner owner = v->owner;
03952 
03953   delete v;
03954   v = NULL; // make sure nobody will try to read 'v' anymore
03955 
03956   if ((trackbits & TRACK_BIT_WORMHOLE) == TRACK_BIT_WORMHOLE) {
03957     /* Vehicle is inside a wormhole, v->u.rail.track contains no useful value then. */
03958     trackbits |= DiagDirToDiagTrackBits(GetTunnelBridgeDirection(tile));
03959   }
03960 
03961   Track track = TrackBitsToTrack(trackbits);
03962   if (HasReservedTracks(tile, trackbits)) {
03963     UnreserveRailTrack(tile, track);
03964 
03965     /* If there are still crashed vehicles on the tile, give the track reservation to them */
03966     TrackBits remaining_trackbits = TRACK_BIT_NONE;
03967     FindVehicleOnPos(tile, &remaining_trackbits, CollectTrackbitsFromCrashedVehiclesEnum);
03968 
03969     /* It is important that these two are the first in the loop, as reservation cannot deal with every trackbit combination */
03970     assert(TRACK_BEGIN == TRACK_X && TRACK_Y == TRACK_BEGIN + 1);
03971     for (Track t = TRACK_BEGIN; t < TRACK_END; t++) {
03972       if (HasBit(remaining_trackbits, t)) {
03973         TryReserveRailTrack(tile, t);
03974       }
03975     }
03976   }
03977 
03978   /* check if the wagon was on a road/rail-crossing */
03979   if (IsLevelCrossingTile(tile)) UpdateLevelCrossing(tile);
03980 
03981   /* Update signals */
03982   if (IsTileType(tile, MP_TUNNELBRIDGE) || IsRailDepotTile(tile)) {
03983     UpdateSignalsOnSegment(tile, INVALID_DIAGDIR, owner);
03984   } else {
03985     SetSignalsOnBothDir(tile, track, owner);
03986   }
03987 }
03988 
03989 static void ChangeTrainDirRandomly(Vehicle *v)
03990 {
03991   static const DirDiff delta[] = {
03992     DIRDIFF_45LEFT, DIRDIFF_SAME, DIRDIFF_SAME, DIRDIFF_45RIGHT
03993   };
03994 
03995   do {
03996     /* We don't need to twist around vehicles if they're not visible */
03997     if (!(v->vehstatus & VS_HIDDEN)) {
03998       v->direction = ChangeDir(v->direction, delta[GB(Random(), 0, 2)]);
03999       v->UpdateDeltaXY(v->direction);
04000       v->cur_image = v->GetImage(v->direction);
04001       /* Refrain from updating the z position of the vehicle when on
04002        * a bridge, because AfterSetTrainPos will put the vehicle under
04003        * the bridge in that case */
04004       if (v->u.rail.track != TRACK_BIT_WORMHOLE) AfterSetTrainPos(v, false);
04005     }
04006   } while ((v = v->Next()) != NULL);
04007 }
04008 
04009 static void HandleCrashedTrain(Vehicle *v)
04010 {
04011   int state = ++v->u.rail.crash_anim_pos;
04012 
04013   if (state == 4 && !(v->vehstatus & VS_HIDDEN)) {
04014     CreateEffectVehicleRel(v, 4, 4, 8, EV_EXPLOSION_LARGE);
04015   }
04016 
04017   uint32 r;
04018   if (state <= 200 && Chance16R(1, 7, r)) {
04019     int index = (r * 10 >> 16);
04020 
04021     Vehicle *u = v;
04022     do {
04023       if (--index < 0) {
04024         r = Random();
04025 
04026         CreateEffectVehicleRel(u,
04027           GB(r,  8, 3) + 2,
04028           GB(r, 16, 3) + 2,
04029           GB(r,  0, 3) + 5,
04030           EV_EXPLOSION_SMALL);
04031         break;
04032       }
04033     } while ((u = u->Next()) != NULL);
04034   }
04035 
04036   if (state <= 240 && !(v->tick_counter & 3)) ChangeTrainDirRandomly(v);
04037 
04038   if (state >= 4440 && !(v->tick_counter & 0x1F)) {
04039     DeleteLastWagon(v);
04040     InvalidateWindow(WC_REPLACE_VEHICLE, (v->group_id << 16) | VEH_TRAIN);
04041   }
04042 }
04043 
04044 static void HandleBrokenTrain(Vehicle *v)
04045 {
04046   if (v->breakdown_ctr != 1) {
04047     v->breakdown_ctr = 1;
04048     v->cur_speed = 0;
04049 
04050     if (v->breakdowns_since_last_service != 255)
04051       v->breakdowns_since_last_service++;
04052 
04053     InvalidateWindow(WC_VEHICLE_VIEW, v->index);
04054     InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
04055 
04056     if (!PlayVehicleSound(v, VSE_BREAKDOWN)) {
04057       SndPlayVehicleFx((_settings_game.game_creation.landscape != LT_TOYLAND) ?
04058         SND_10_TRAIN_BREAKDOWN : SND_3A_COMEDY_BREAKDOWN_2, v);
04059     }
04060 
04061     if (!(v->vehstatus & VS_HIDDEN)) {
04062       Vehicle *u = CreateEffectVehicleRel(v, 4, 4, 5, EV_BREAKDOWN_SMOKE);
04063       if (u != NULL) u->u.effect.animation_state = v->breakdown_delay * 2;
04064     }
04065   }
04066 
04067   if (!(v->tick_counter & 3)) {
04068     if (!--v->breakdown_delay) {
04069       v->breakdown_ctr = 0;
04070       InvalidateWindow(WC_VEHICLE_VIEW, v->index);
04071     }
04072   }
04073 }
04074 
04076 static const uint16 _breakdown_speeds[16] = {
04077   225, 210, 195, 180, 165, 150, 135, 120, 105, 90, 75, 60, 45, 30, 15, 15
04078 };
04079 
04080 
04088 static bool TrainApproachingLineEnd(Vehicle *v, bool signal)
04089 {
04090   /* Calc position within the current tile */
04091   uint x = v->x_pos & 0xF;
04092   uint y = v->y_pos & 0xF;
04093 
04094   /* for diagonal directions, 'x' will be 0..15 -
04095    * for other directions, it will be 1, 3, 5, ..., 15 */
04096   switch (v->direction) {
04097     case DIR_N : x = ~x + ~y + 25; break;
04098     case DIR_NW: x = y;            // FALLTHROUGH
04099     case DIR_NE: x = ~x + 16;      break;
04100     case DIR_E : x = ~x + y + 9;   break;
04101     case DIR_SE: x = y;            break;
04102     case DIR_S : x = x + y - 7;    break;
04103     case DIR_W : x = ~y + x + 9;   break;
04104     default: break;
04105   }
04106 
04107   /* do not reverse when approaching red signal */
04108   if (!signal && x + (v->u.rail.cached_veh_length + 1) / 2 >= TILE_SIZE) {
04109     /* we are too near the tile end, reverse now */
04110     v->cur_speed = 0;
04111     ReverseTrainDirection(v);
04112     return false;
04113   }
04114 
04115   /* slow down */
04116   v->vehstatus |= VS_TRAIN_SLOWING;
04117   uint16 break_speed = _breakdown_speeds[x & 0xF];
04118   if (break_speed < v->cur_speed) v->cur_speed = break_speed;
04119 
04120   return true;
04121 }
04122 
04123 
04129 static bool TrainCanLeaveTile(const Vehicle *v)
04130 {
04131   /* Exit if inside a tunnel/bridge or a depot */
04132   if (v->u.rail.track == TRACK_BIT_WORMHOLE || v->u.rail.track == TRACK_BIT_DEPOT) return false;
04133 
04134   TileIndex tile = v->tile;
04135 
04136   /* entering a tunnel/bridge? */
04137   if (IsTileType(tile, MP_TUNNELBRIDGE)) {
04138     DiagDirection dir = GetTunnelBridgeDirection(tile);
04139     if (DiagDirToDir(dir) == v->direction) return false;
04140   }
04141 
04142   /* entering a depot? */
04143   if (IsRailDepotTile(tile)) {
04144     DiagDirection dir = ReverseDiagDir(GetRailDepotDirection(tile));
04145     if (DiagDirToDir(dir) == v->direction) return false;
04146   }
04147 
04148   return true;
04149 }
04150 
04151 
04159 static TileIndex TrainApproachingCrossingTile(const Vehicle *v)
04160 {
04161   assert(IsFrontEngine(v));
04162   assert(!(v->vehstatus & VS_CRASHED));
04163 
04164   if (!TrainCanLeaveTile(v)) return INVALID_TILE;
04165 
04166   DiagDirection dir = TrainExitDir(v->direction, v->u.rail.track);
04167   TileIndex tile = v->tile + TileOffsByDiagDir(dir);
04168 
04169   /* not a crossing || wrong axis || unusable rail (wrong type or owner) */
04170   if (!IsLevelCrossingTile(tile) || DiagDirToAxis(dir) == GetCrossingRoadAxis(tile) ||
04171       !CheckCompatibleRail(v, tile)) {
04172     return INVALID_TILE;
04173   }
04174 
04175   return tile;
04176 }
04177 
04178 
04185 static bool TrainCheckIfLineEnds(Vehicle *v)
04186 {
04187   /* First, handle broken down train */
04188 
04189   int t = v->breakdown_ctr;
04190   if (t > 1) {
04191     v->vehstatus |= VS_TRAIN_SLOWING;
04192 
04193     uint16 break_speed = _breakdown_speeds[GB(~t, 4, 4)];
04194     if (break_speed < v->cur_speed) v->cur_speed = break_speed;
04195   } else {
04196     v->vehstatus &= ~VS_TRAIN_SLOWING;
04197   }
04198 
04199   if (!TrainCanLeaveTile(v)) return true;
04200 
04201   /* Determine the non-diagonal direction in which we will exit this tile */
04202   DiagDirection dir = TrainExitDir(v->direction, v->u.rail.track);
04203   /* Calculate next tile */
04204   TileIndex tile = v->tile + TileOffsByDiagDir(dir);
04205 
04206   /* Determine the track status on the next tile */
04207   TrackStatus ts = GetTileTrackStatus(tile, TRANSPORT_RAIL, 0, ReverseDiagDir(dir));
04208   TrackdirBits reachable_trackdirs = DiagdirReachesTrackdirs(dir);
04209 
04210   TrackdirBits trackdirbits = TrackStatusToTrackdirBits(ts) & reachable_trackdirs;
04211   TrackdirBits red_signals = TrackStatusToRedSignals(ts) & reachable_trackdirs;
04212 
04213   /* We are sure the train is not entering a depot, it is detected above */
04214 
04215   /* mask unreachable track bits if we are forbidden to do 90deg turns */
04216   TrackBits bits = TrackdirBitsToTrackBits(trackdirbits);
04217   if (_settings_game.pf.pathfinder_for_trains != VPF_NTP && _settings_game.pf.forbid_90_deg) {
04218     bits &= ~TrackCrossesTracks(FindFirstTrack(v->u.rail.track));
04219   }
04220 
04221   /* no suitable trackbits at all || unusable rail (wrong type or owner) */
04222   if (bits == TRACK_BIT_NONE || !CheckCompatibleRail(v, tile)) {
04223     return TrainApproachingLineEnd(v, false);
04224   }
04225 
04226   /* approaching red signal */
04227   if ((trackdirbits & red_signals) != 0) return TrainApproachingLineEnd(v, true);
04228 
04229   /* approaching a rail/road crossing? then make it red */
04230   if (IsLevelCrossingTile(tile)) MaybeBarCrossingWithSound(tile);
04231 
04232   return true;
04233 }
04234 
04235 
04236 static void TrainLocoHandler(Vehicle *v, bool mode)
04237 {
04238   /* train has crashed? */
04239   if (v->vehstatus & VS_CRASHED) {
04240     if (!mode) HandleCrashedTrain(v);
04241     return;
04242   }
04243 
04244   if (v->u.rail.force_proceed != 0) {
04245     v->u.rail.force_proceed--;
04246     ClrBit(v->u.rail.flags, VRF_TRAIN_STUCK);
04247     InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
04248   }
04249 
04250   /* train is broken down? */
04251   if (v->breakdown_ctr != 0) {
04252     if (v->breakdown_ctr <= 2) {
04253       HandleBrokenTrain(v);
04254       return;
04255     }
04256     if (!v->current_order.IsType(OT_LOADING)) v->breakdown_ctr--;
04257   }
04258 
04259   if (HasBit(v->u.rail.flags, VRF_REVERSING) && v->cur_speed == 0) {
04260     ReverseTrainDirection(v);
04261   }
04262 
04263   /* exit if train is stopped */
04264   if (v->vehstatus & VS_STOPPED && v->cur_speed == 0) return;
04265 
04266   bool valid_order = v->current_order.IsValid() && v->current_order.GetType() != OT_CONDITIONAL;
04267   if (ProcessOrders(v) && CheckReverseTrain(v)) {
04268     v->load_unload_time_rem = 0;
04269     v->cur_speed = 0;
04270     v->subspeed = 0;
04271     ReverseTrainDirection(v);
04272     return;
04273   }
04274 
04275   v->HandleLoading(mode);
04276 
04277   if (v->current_order.IsType(OT_LOADING)) return;
04278 
04279   if (CheckTrainStayInDepot(v)) return;
04280 
04281   if (!mode) HandleLocomotiveSmokeCloud(v);
04282 
04283   /* We had no order but have an order now, do look ahead. */
04284   if (!valid_order && v->current_order.IsValid()) {
04285     CheckNextTrainTile(v);
04286   }
04287 
04288   /* Handle stuck trains. */
04289   if (!mode && HasBit(v->u.rail.flags, VRF_TRAIN_STUCK)) {
04290     ++v->load_unload_time_rem;
04291 
04292     /* Should we try reversing this tick if still stuck? */
04293     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;
04294 
04295     if (!turn_around && v->load_unload_time_rem % _settings_game.pf.path_backoff_interval != 0 && v->u.rail.force_proceed == 0) return;
04296     if (!TryPathReserve(v)) {
04297       /* Still stuck. */
04298       if (turn_around) ReverseTrainDirection(v);
04299 
04300       if (HasBit(v->u.rail.flags, VRF_TRAIN_STUCK) && v->load_unload_time_rem > 2 * _settings_game.pf.wait_for_pbs_path * DAY_TICKS) {
04301         /* Show message to player. */
04302         if (_settings_client.gui.lost_train_warn && v->owner == _local_company) {
04303           SetDParam(0, v->index);
04304           AddNewsItem(
04305             STR_TRAIN_IS_STUCK,
04306             NS_ADVICE,
04307             v->index,
04308             0);
04309         }
04310         v->load_unload_time_rem = 0;
04311       }
04312       /* Exit if force proceed not pressed, else reset stuck flag anyway. */
04313       if (v->u.rail.force_proceed == 0) return;
04314       ClrBit(v->u.rail.flags, VRF_TRAIN_STUCK);
04315       v->load_unload_time_rem = 0;
04316       InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
04317     }
04318   }
04319 
04320   if (v->current_order.IsType(OT_LEAVESTATION)) {
04321     v->current_order.Free();
04322     InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
04323     return;
04324   }
04325 
04326   int j = UpdateTrainSpeed(v);
04327 
04328   /* we need to invalidate the widget if we are stopping from 'Stopping 0 km/h' to 'Stopped' */
04329   if (v->cur_speed == 0 && v->u.rail.last_speed == 0 && v->vehstatus & VS_STOPPED) {
04330     InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
04331   }
04332 
04333   int adv_spd = (v->direction & 1) ? 192 : 256;
04334   if (j < adv_spd) {
04335     /* if the vehicle has speed 0, update the last_speed field. */
04336     if (v->cur_speed == 0) SetLastSpeed(v, v->cur_speed);
04337   } else {
04338     TrainCheckIfLineEnds(v);
04339     /* Loop until the train has finished moving. */
04340     for (;;) {
04341       j -= adv_spd;
04342       TrainController(v, NULL);
04343       /* Don't continue to move if the train crashed. */
04344       if (CheckTrainCollision(v)) break;
04345       /* 192 spd used for going straight, 256 for going diagonally. */
04346       adv_spd = (v->direction & 1) ? 192 : 256;
04347 
04348       /* No more moving this tick */
04349       if (j < adv_spd || v->cur_speed == 0) break;
04350 
04351       OrderType order_type = v->current_order.GetType();
04352       /* Do not skip waypoints (incl. 'via' stations) when passing through at full speed. */
04353       if ((order_type == OT_GOTO_WAYPOINT &&
04354             v->dest_tile == v->tile) ||
04355           (order_type == OT_GOTO_STATION &&
04356             (v->current_order.GetNonStopType() & ONSF_NO_STOP_AT_DESTINATION_STATION) &&
04357             IsTileType(v->tile, MP_STATION) &&
04358             v->current_order.GetDestination() == GetStationIndex(v->tile))) {
04359         ProcessOrders(v);
04360       }
04361     }
04362     SetLastSpeed(v, v->cur_speed);
04363   }
04364 
04365   for (Vehicle *u = v; u != NULL; u = u->Next()) {
04366     if ((u->vehstatus & VS_HIDDEN) != 0) continue;
04367 
04368     uint16 old_image = u->cur_image;
04369     u->cur_image = u->GetImage(u->direction);
04370     if (old_image != u->cur_image) VehicleMove(u, true);
04371   }
04372 
04373   if (v->progress == 0) v->progress = j; // Save unused spd for next time, if TrainController didn't set progress
04374 }
04375 
04376 
04377 
04378 Money Train::GetRunningCost() const
04379 {
04380   Money cost = 0;
04381   const Vehicle *v = this;
04382 
04383   do {
04384     const RailVehicleInfo *rvi = RailVehInfo(v->engine_type);
04385 
04386     byte cost_factor = GetVehicleProperty(v, 0x0D, rvi->running_cost);
04387     if (cost_factor == 0) continue;
04388 
04389     /* Halve running cost for multiheaded parts */
04390     if (IsMultiheaded(v)) cost_factor /= 2;
04391 
04392     cost += cost_factor * GetPriceByIndex(rvi->running_cost_class);
04393   } while ((v = GetNextVehicle(v)) != NULL);
04394 
04395   return cost;
04396 }
04397 
04398 
04399 void Train::Tick()
04400 {
04401   if (_age_cargo_skip_counter == 0) this->cargo.AgeCargo();
04402 
04403   this->tick_counter++;
04404 
04405   if (IsFrontEngine(this)) {
04406     if (!(this->vehstatus & VS_STOPPED)) this->running_ticks++;
04407     this->current_order_time++;
04408 
04409     TrainLocoHandler(this, false);
04410 
04411     /* make sure vehicle wasn't deleted. */
04412     if (this->type == VEH_TRAIN && IsFrontEngine(this))
04413       TrainLocoHandler(this, true);
04414   } else if (IsFreeWagon(this) && HASBITS(this->vehstatus, VS_CRASHED)) {
04415     /* Delete flooded standalone wagon chain */
04416     if (++this->u.rail.crash_anim_pos >= 4400) delete this;
04417   }
04418 }
04419 
04420 static void CheckIfTrainNeedsService(Vehicle *v)
04421 {
04422   static const uint MAX_ACCEPTABLE_DEPOT_DIST = 16;
04423 
04424   if (_settings_game.vehicle.servint_trains == 0 || !v->NeedsAutomaticServicing()) return;
04425   if (v->IsInDepot()) {
04426     VehicleServiceInDepot(v);
04427     return;
04428   }
04429 
04430   TrainFindDepotData tfdd = FindClosestTrainDepot(v, MAX_ACCEPTABLE_DEPOT_DIST);
04431   /* Only go to the depot if it is not too far out of our way. */
04432   if (tfdd.best_length == UINT_MAX || tfdd.best_length > MAX_ACCEPTABLE_DEPOT_DIST) {
04433     if (v->current_order.IsType(OT_GOTO_DEPOT)) {
04434       /* If we were already heading for a depot but it has
04435        * suddenly moved farther away, we continue our normal
04436        * schedule? */
04437       v->current_order.MakeDummy();
04438       InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
04439     }
04440     return;
04441   }
04442 
04443   const Depot *depot = GetDepotByTile(tfdd.tile);
04444 
04445   if (v->current_order.IsType(OT_GOTO_DEPOT) &&
04446       v->current_order.GetDestination() != depot->index &&
04447       !Chance16(3, 16)) {
04448     return;
04449   }
04450 
04451   v->current_order.MakeGoToDepot(depot->index, ODTFB_SERVICE);
04452   v->dest_tile = tfdd.tile;
04453   InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);
04454 }
04455 
04456 void Train::OnNewDay()
04457 {
04458   if ((++this->day_counter & 7) == 0) DecreaseVehicleValue(this);
04459 
04460   if (IsFrontEngine(this)) {
04461     CheckVehicleBreakdown(this);
04462     AgeVehicle(this);
04463 
04464     CheckIfTrainNeedsService(this);
04465 
04466     CheckOrders(this);
04467 
04468     /* update destination */
04469     if (this->current_order.IsType(OT_GOTO_STATION)) {
04470       TileIndex tile = GetStation(this->current_order.GetDestination())->train_tile;
04471       if (tile != INVALID_TILE) this->dest_tile = tile;
04472     }
04473 
04474     if (this->running_ticks != 0) {
04475       /* running costs */
04476       CommandCost cost(EXPENSES_TRAIN_RUN, this->GetRunningCost() * this->running_ticks / (DAYS_IN_YEAR  * DAY_TICKS));
04477 
04478       this->profit_this_year -= cost.GetCost();
04479       this->running_ticks = 0;
04480 
04481       SubtractMoneyFromCompanyFract(this->owner, cost);
04482 
04483       InvalidateWindow(WC_VEHICLE_DETAILS, this->index);
04484       InvalidateWindowClasses(WC_TRAINS_LIST);
04485     }
04486   } else if (IsTrainEngine(this)) {
04487     /* Also age engines that aren't front engines */
04488     AgeVehicle(this);
04489   }
04490 }
04491 
04492 void InitializeTrains()
04493 {
04494   _age_cargo_skip_counter = 1;
04495 }

Generated on Wed Jun 3 19:05:16 2009 for OpenTTD by  doxygen 1.5.6