Add drive-through train depot emulation (default off)

src/lang/english.txt

@@ -1307,6 +1307,9 @@ STR_CONFIG_SETTING_FLIP_DIRECTION_ALL_TRAINS_HELPTEXT           :Enable flipping
 STR_CONFIG_SETTING_ROADVEH_ARTICULATED_OVERTAKING               :Articulated road vehicles may overtake: {STRING2}
 STR_CONFIG_SETTING_ROADVEH_ARTICULATED_OVERTAKING_HELPTEXT      :Enable articulated road vehicles to overtake other road vehicles.
 
+STR_CONFIG_SETTING_DRIVE_THROUGH_TRAIN_DEPOT                    :Drive-through train depots: {STRING2}
+STR_CONFIG_SETTING_DRIVE_THROUGH_TRAIN_DEPOT_HELPTEXT           :Enable emulation of drive-through train depots. Trains can move between depots placed back to back, optionally with intermediary depots in between. Requires the YAPF pathfinder.
+
 STR_CONFIG_SETTING_COMPANY_STARTING_COLOUR                      :Starting company colour: {STRING2}
 STR_CONFIG_SETTING_COMPANY_STARTING_COLOUR_HELPTEXT             :Choose starting colour for the company
 
@@ -4610,6 +4613,7 @@ STR_VEHICLE_STATUS_TRAIN_STUCK_WAIT_RESTRICTION                 :{ORANGE}Waiting
 STR_VEHICLE_STATUS_AIRCRAFT_TOO_FAR                             :{ORANGE}Too far to next destination
 STR_VEHICLE_STATUS_TRAIN_WAITING_TIMETABLE                      :{ORANGE}Waiting due to timetable
 STR_VEHICLE_STATUS_TRAIN_REVERSING                              :{ORANGE}Reversing, {VELOCITY}
+STR_VEHICLE_STATUS_TRAIN_MOVING_DEPOT                           :{ORANGE}Moving in depot
 
 STR_BREAKDOWN_TYPE_CRITICAL                                     :Mechanical failure
 STR_BREAKDOWN_TYPE_EM_STOP                                      :Emergency stop

src/pathfinder/yapf/yapf.h

@@ -86,6 +86,8 @@ FindDepotData YapfTrainFindNearestDepot(const Train *v, int max_distance);
  */
 bool YapfTrainCheckReverse(const Train *v);
 
+bool YapfTrainCheckDepotReverse(const Train *v, TileIndex forward_depot, TileIndex reverse_depot);
+
 /**
  * Try to extend the reserved path of a train to the nearest safe tile using YAPF.
  *

src/pathfinder/yapf/yapf_rail.cpp

@@ -724,6 +724,22 @@ bool YapfTrainCheckReverse(const Train *v)
 	return reverse;
 }
 
+bool YapfTrainCheckDepotReverse(const Train *v, TileIndex forward_depot, TileIndex reverse_depot)
+{
+	typedef bool (*PfnCheckReverseTrain)(const Train*, TileIndex, Trackdir, TileIndex, Trackdir, int);
+	PfnCheckReverseTrain pfnCheckReverseTrain = CYapfRail1::stCheckReverseTrain;
+
+	/* check if non-default YAPF type needed */
+	if (_settings_game.pf.forbid_90_deg) {
+		pfnCheckReverseTrain = &CYapfRail2::stCheckReverseTrain; // Trackdir, forbid 90-deg
+	}
+
+	bool reverse = pfnCheckReverseTrain(v, forward_depot, DiagDirToDiagTrackdir(GetRailDepotDirection(forward_depot)),
+			reverse_depot, DiagDirToDiagTrackdir(GetRailDepotDirection(reverse_depot)), 1);
+
+	return reverse;
+}
+
 FindDepotData YapfTrainFindNearestDepot(const Train *v, int max_penalty)
 {
 	const Train *last_veh = v->Last();

src/saveload/extended_ver_sl.cpp

@@ -133,6 +133,7 @@ const SlxiSubChunkInfo _sl_xv_sub_chunk_infos[] = {
 	{ XSLFI_SHIP_LOST_COUNTER,      XSCF_NULL,                1,   1, "ship_lost_counter",         nullptr, nullptr, nullptr        },
 	{ XSLFI_BUILD_OBJECT_RATE_LIMIT,XSCF_NULL,                1,   1, "build_object_rate_limit",   nullptr, nullptr, nullptr        },
 	{ XSLFI_LOCAL_COMPANY,          XSCF_IGNORABLE_ALL,       1,   1, "local_company",             saveLC,  loadLC,  nullptr        },
+	{ XSLFI_THROUGH_TRAIN_DEPOT,    XSCF_NULL,                1,   1, "drive_through_train_depot", nullptr, nullptr, nullptr        },
 	{ XSLFI_NULL, XSCF_NULL, 0, 0, nullptr, nullptr, nullptr, nullptr },// This is the end marker
 };
 

src/saveload/extended_ver_sl.h

@@ -87,6 +87,7 @@ enum SlXvFeatureIndex {
 	XSLFI_SHIP_LOST_COUNTER,                      ///< Ship lost counter
 	XSLFI_BUILD_OBJECT_RATE_LIMIT,                ///< Build object rate limit
 	XSLFI_LOCAL_COMPANY,                          ///< Local company ID
+	XSLFI_THROUGH_TRAIN_DEPOT,                    ///< Drive-through train depots
 
 	XSLFI_RIFF_HEADER_60_BIT,                     ///< Size field in RIFF chunk header is 60 bit
 	XSLFI_HEIGHT_8_BIT,                           ///< Map tile height is 8 bit instead of 4 bit, but savegame version may be before this became true in trunk

src/settings_gui.cpp

@@ -1830,6 +1830,7 @@ static SettingsContainer &GetSettingsTree()
 				routing->Add(new SettingEntry("pf.pathfinder_for_roadvehs"));
 				routing->Add(new SettingEntry("pf.pathfinder_for_ships"));
 				routing->Add(new SettingEntry("pf.reroute_rv_on_layout_change"));
+				routing->Add(new SettingEntry("vehicle.drive_through_train_depot"));
 			}
 
 			vehicles->Add(new SettingEntry("order.no_servicing_if_no_breakdowns"));

src/settings_type.h

@@ -561,6 +561,7 @@ struct VehicleSettings {
 	bool   no_train_crash_other_company;     ///< trains cannot crash with trains from other companies
 	bool   flip_direction_all_trains;        ///< enable flipping direction in depot for all train engine types
 	bool   roadveh_articulated_overtaking;   ///< enable articulated road vehicles overtaking other vehicles
+	bool   drive_through_train_depot;        ///< enable drive-through train depot emulation
 };
 
 /** Settings related to the economy. */

src/table/settings.ini

@@ -1706,6 +1706,14 @@ strhelp  = STR_CONFIG_SETTING_ROADVEH_ARTICULATED_OVERTAKING_HELPTEXT
 patxname = ""roadveh_articulated_overtaking.vehicle.roadveh_articulated_overtaking""
 cat      = SC_BASIC
 
+[SDT_BOOL]
+base     = GameSettings
+var      = vehicle.drive_through_train_depot
+def      = false
+str      = STR_CONFIG_SETTING_DRIVE_THROUGH_TRAIN_DEPOT
+strhelp  = STR_CONFIG_SETTING_DRIVE_THROUGH_TRAIN_DEPOT_HELPTEXT
+patxname = ""drive_through_train_depot.vehicle.drive_through_train_depot""
+
 ; station.join_stations
 [SDT_NULL]
 length   = 1

src/train_cmd.cpp

@@ -2598,6 +2598,12 @@ static bool CheckTrainStayInDepot(Train *v)
 		return true;
 	}
 
+	if (v->reverse_distance > 0) {
+		v->reverse_distance--;
+		if (v->reverse_distance == 0) SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
+		return true;
+	}
+
 	SigSegState seg_state;
 
 	if (v->force_proceed == TFP_NONE) {
@@ -2628,6 +2634,53 @@ static bool CheckTrainStayInDepot(Train *v)
 		return true;
 	}
 
+	if (_settings_game.pf.pathfinder_for_trains == VPF_YAPF && _settings_game.vehicle.drive_through_train_depot) {
+		const TileIndex depot_tile = v->tile;
+		const DiagDirection depot_dir = GetRailDepotDirection(depot_tile);
+		const DiagDirection behind_depot_dir = ReverseDiagDir(depot_dir);
+		const int depot_z = GetTileMaxZ(depot_tile);
+		const TileIndexDiffC tile_diff = TileIndexDiffCByDiagDir(behind_depot_dir);
+
+		TileIndex behind_depot_tile = depot_tile;
+		uint skipped = 0;
+
+		while (true) {
+			TileIndex tile = AddTileIndexDiffCWrap(behind_depot_tile, tile_diff);
+			if (tile == INVALID_TILE) break;
+			if (!IsRailDepotTile(tile)) break;
+			DiagDirection dir = GetRailDepotDirection(tile);
+			if (dir != depot_dir && dir != behind_depot_dir) break;
+			if (!HasBit(v->compatible_railtypes, GetRailType(tile))) break;
+			if (GetTileMaxZ(tile) != depot_z) break;
+			behind_depot_tile = tile;
+			skipped++;
+		}
+
+		if (skipped > 0 && GetRailDepotDirection(behind_depot_tile) == behind_depot_dir &&
+				YapfTrainCheckDepotReverse(v, depot_tile, behind_depot_tile)) {
+			Direction direction = DiagDirToDir(behind_depot_dir);
+			int x = TileX(behind_depot_tile) * TILE_SIZE | _vehicle_initial_x_fract[behind_depot_dir];
+			int y = TileY(behind_depot_tile) * TILE_SIZE | _vehicle_initial_y_fract[behind_depot_dir];
+			if (v->gcache.cached_total_length < skipped * TILE_SIZE) {
+				int delta = (skipped * TILE_SIZE) - v->gcache.cached_total_length;
+				int speed = max(1, v->GetCurrentMaxSpeed());
+				v->reverse_distance = (1 + (((192 * 3 / 2) * delta) / speed));
+				SetWindowWidgetDirty(WC_VEHICLE_VIEW, v->index, WID_VV_START_STOP);
+			}
+
+			for (Train *u = v; u != nullptr; u = u->Next()) {
+				u->tile = behind_depot_tile;
+				u->direction = direction;
+				u->x_pos = x;
+				u->y_pos = y;
+			}
+
+			InvalidateWindowData(WC_VEHICLE_DEPOT, depot_tile);
+			InvalidateWindowData(WC_VEHICLE_DEPOT, behind_depot_tile);
+			return true;
+		}
+	}
+
 	/* Only leave when we can reserve a path to our destination. */
 	if (seg_state == SIGSEG_PBS && !TryPathReserve(v) && v->force_proceed == TFP_NONE) {
 		/* No path and no force proceed. */

src/vehicle_gui.cpp

@@ -3356,8 +3356,12 @@ public:
 		} else if (v->type == VEH_TRAIN && HasBit(Train::From(v)->flags, VRF_TRAIN_STUCK) && !v->current_order.IsType(OT_LOADING) && !mouse_over_start_stop) {
 			str = HasBit(Train::From(v)->flags, VRF_WAITING_RESTRICTION) ? STR_VEHICLE_STATUS_TRAIN_STUCK_WAIT_RESTRICTION : STR_VEHICLE_STATUS_TRAIN_STUCK;
 		} else if (v->type == VEH_TRAIN && Train::From(v)->reverse_distance > 1) {
-			str = STR_VEHICLE_STATUS_TRAIN_REVERSING;
-			SetDParam(0, v->GetDisplaySpeed());
+			if (Train::From(v)->track == TRACK_BIT_DEPOT) {
+				str = STR_VEHICLE_STATUS_TRAIN_MOVING_DEPOT;
+			} else {
+				str = STR_VEHICLE_STATUS_TRAIN_REVERSING;
+				SetDParam(0, v->GetDisplaySpeed());
+			}
 		} else if (v->type == VEH_AIRCRAFT && HasBit(Aircraft::From(v)->flags, VAF_DEST_TOO_FAR) && !v->current_order.IsType(OT_LOADING)) {
 			str = STR_VEHICLE_STATUS_AIRCRAFT_TOO_FAR;
 		} else { // vehicle is in a "normal" state, show current order