Add reverse at waypoint orders.

The train will reverse when its tail is within the waypoint tile.
This is useful for reversing on train en-route, without creating
dedicated reversing sidings or platforms.

src/lang/english.txt

@@ -3771,6 +3771,9 @@ STR_ORDER_REFIT_AUTO_TOOLTIP                                    :{BLACK}Select w
 STR_ORDER_DROP_REFIT_AUTO                                       :Fixed cargo
 STR_ORDER_DROP_REFIT_AUTO_ANY                                   :Available cargo
 
+STR_ORDER_REVERSE                                               :{BLACK}Reverse
+STR_ORDER_REVERSE_TOOLTIP                                       :{BLACK}Change the reversing behaviour of the highlighted order.
+
 STR_ORDER_SERVICE                                               :{BLACK}Service
 STR_ORDER_DROP_GO_ALWAYS_DEPOT                                  :Always go
 STR_ORDER_DROP_SERVICE_DEPOT                                    :Service if needed
@@ -3822,6 +3825,8 @@ STR_ORDERS_VEH_WITH_SHARED_ORDERS_LIST_TOOLTIP                  :{BLACK}Show all
 # String parts to build the order string
 STR_ORDER_GO_TO_WAYPOINT                                        :Go via {WAYPOINT}
 STR_ORDER_GO_NON_STOP_TO_WAYPOINT                               :Go non-stop via {WAYPOINT}
+STR_ORDER_GO_TO_WAYPOINT_REVERSE                                :Go via and reverse at {WAYPOINT}
+STR_ORDER_GO_NON_STOP_TO_WAYPOINT_REVERSE                       :Go non-stop via and reverse at {WAYPOINT}
 
 STR_ORDER_SERVICE_AT                                            :Service at
 STR_ORDER_SERVICE_NON_STOP_AT                                   :Service non-stop at

src/order_cmd.cpp

@@ -1315,7 +1315,7 @@ CommandCost CmdModifyOrder(TileIndex tile, DoCommandFlag flags, uint32 p1, uint3
 			break;
 
 		case OT_GOTO_WAYPOINT:
-			if (mof != MOF_NON_STOP) return CMD_ERROR;
+			if (mof != MOF_NON_STOP && mof != MOF_WAYPOINT_FLAGS) return CMD_ERROR;
 			break;
 
 		case OT_CONDITIONAL:
@@ -1397,6 +1397,10 @@ CommandCost CmdModifyOrder(TileIndex tile, DoCommandFlag flags, uint32 p1, uint3
 		case MOF_COND_DESTINATION:
 			if (data >= v->GetNumOrders()) return CMD_ERROR;
 			break;
+
+		case MOF_WAYPOINT_FLAGS:
+			if (data != (data & OWF_REVERSE)) return CMD_ERROR;
+			break;
 	}
 
 	if (flags & DC_EXEC) {
@@ -1486,6 +1490,10 @@ CommandCost CmdModifyOrder(TileIndex tile, DoCommandFlag flags, uint32 p1, uint3
 				order->SetConditionSkipToOrder(data);
 				break;
 
+			case MOF_WAYPOINT_FLAGS:
+				order->SetWaypointFlags((OrderWaypointFlags)data);
+				break;
+
 			default: NOT_REACHED();
 		}
 

src/order_gui.cpp

@@ -314,10 +314,13 @@ void DrawOrderString(const Vehicle *v, const Order *order, int order_index, int
 			}
 			break;
 
-		case OT_GOTO_WAYPOINT:
+		case OT_GOTO_WAYPOINT: {
-			SetDParam(0, (order->GetNonStopType() & ONSF_NO_STOP_AT_INTERMEDIATE_STATIONS) ? STR_ORDER_GO_NON_STOP_TO_WAYPOINT : STR_ORDER_GO_TO_WAYPOINT);
+			StringID str = (order->GetNonStopType() & ONSF_NO_STOP_AT_INTERMEDIATE_STATIONS) ? STR_ORDER_GO_NON_STOP_TO_WAYPOINT : STR_ORDER_GO_TO_WAYPOINT;
+			if (order->GetWaypointFlags() & OWF_REVERSE) str += STR_ORDER_GO_TO_WAYPOINT_REVERSE - STR_ORDER_GO_TO_WAYPOINT;
+			SetDParam(0, str);
 			SetDParam(1, order->GetDestination());
 			break;
+		}
 
 		case OT_CONDITIONAL:
 			SetDParam(1, order->GetConditionSkipToOrder() + 1);
@@ -489,6 +492,7 @@ private:
 		/* WID_O_SEL_TOP_LEFT */
 		DP_LEFT_LOAD       = 0, ///< Display 'load' in the left button of the top row of the train/rv order window.
 		DP_LEFT_REFIT      = 1, ///< Display 'refit' in the left button of the top row of the train/rv order window.
+		DP_LEFT_REVERSE    = 2, ///< Display 'reverse' in the left button of the top row of the train/rv order window.
 
 		/* WID_O_SEL_TOP_MIDDLE */
 		DP_MIDDLE_UNLOAD   = 0, ///< Display 'unload' in the middle button of the top row of the train/rv order window.
@@ -999,13 +1003,14 @@ public:
 						row_sel->SetDisplayedPlane(DP_ROW_LOAD);
 					} else {
 						train_row_sel->SetDisplayedPlane(DP_GROUNDVEHICLE_ROW_NORMAL);
-						left_sel->SetDisplayedPlane(DP_LEFT_LOAD);
+						left_sel->SetDisplayedPlane(DP_LEFT_REVERSE);
 						middle_sel->SetDisplayedPlane(DP_MIDDLE_UNLOAD);
 						right_sel->SetDisplayedPlane(DP_RIGHT_EMPTY);
 						this->EnableWidget(WID_O_NON_STOP);
 						this->SetWidgetLoweredState(WID_O_NON_STOP, order->GetNonStopType() & ONSF_NO_STOP_AT_INTERMEDIATE_STATIONS);
+						this->EnableWidget(WID_O_REVERSE);
+						this->SetWidgetLoweredState(WID_O_REVERSE, order->GetWaypointFlags() & OWF_REVERSE);
 					}
-					this->DisableWidget(WID_O_FULL_LOAD);
 					this->DisableWidget(WID_O_UNLOAD);
 					this->DisableWidget(WID_O_REFIT_DROPDOWN);
 					break;
@@ -1287,6 +1292,17 @@ public:
 				}
 				break;
 
+			case WID_O_REVERSE: {
+				VehicleOrderID sel_ord = this->OrderGetSel();
+				const Order *order = this->vehicle->GetOrder(sel_ord);
+
+				if (order == NULL) break;
+
+				DoCommandP(this->vehicle->tile, this->vehicle->index + (sel_ord << 20), MOF_WAYPOINT_FLAGS | (order->GetWaypointFlags() ^ OWF_REVERSE) << 4,
+						CMD_MODIFY_ORDER | CMD_MSG(STR_ERROR_CAN_T_MODIFY_THIS_ORDER));
+				break;
+			}
+
 			case WID_O_TIMETABLE_VIEW:
 				ShowTimetableWindow(this->vehicle);
 				break;
@@ -1555,6 +1571,8 @@ static const NWidgetPart _nested_orders_train_widgets[] = {
 															SetDataTip(STR_ORDER_TOGGLE_FULL_LOAD, STR_ORDER_TOOLTIP_FULL_LOAD), SetResize(1, 0),
 					NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_O_REFIT), SetMinimalSize(93, 12), SetFill(1, 0),
 															SetDataTip(STR_ORDER_REFIT, STR_ORDER_REFIT_TOOLTIP), SetResize(1, 0),
+					NWidget(WWT_TEXTBTN, COLOUR_GREY, WID_O_REVERSE), SetMinimalSize(93, 12), SetFill(1, 0),
+															SetDataTip(STR_ORDER_REVERSE, STR_ORDER_REVERSE_TOOLTIP), SetResize(1, 0),
 				EndContainer(),
 				NWidget(NWID_SELECTION, INVALID_COLOUR, WID_O_SEL_TOP_MIDDLE),
 					NWidget(NWID_BUTTON_DROPDOWN, COLOUR_GREY, WID_O_UNLOAD), SetMinimalSize(93, 12), SetFill(1, 0),

src/order_type.h

@@ -117,6 +117,7 @@ DECLARE_ENUM_AS_BIT_SET(OrderDepotActionFlags)
  */
 enum OrderWaypointFlags {
 	OWF_DEFAULT          = 0,      ///< Default waypoint behaviour
+	OWF_REVERSE          = 1 << 0, ///< Reverse train at the waypoint
 };
 DECLARE_ENUM_AS_BIT_SET(OrderWaypointFlags)
 
@@ -163,6 +164,7 @@ enum ModifyOrderFlags {
 	MOF_COND_COMPARATOR, ///< A comparator changes.
 	MOF_COND_VALUE,      ///< The value to set the condition to.
 	MOF_COND_DESTINATION,///< Change the destination of a conditional order.
+	MOF_WAYPOINT_FLAGS,  ///< Change the waypoint flags
 	MOF_END
 };
 template <> struct EnumPropsT<ModifyOrderFlags> : MakeEnumPropsT<ModifyOrderFlags, byte, MOF_NON_STOP, MOF_END, MOF_END, 4> {};

src/saveload/afterload.cpp

@@ -2951,6 +2951,13 @@ bool AfterLoadGame()
 		}
 	}
 
+	if (SlXvIsFeatureMissing(XSLFI_REVERSE_AT_WAYPOINT)) {
+		Train *t;
+		FOR_ALL_TRAINS(t) {
+			t->reverse_distance = 0;
+		}
+	}
+
 	/*
 	 * Only keep order-backups for network clients (and when replaying).
 	 * If we are a network server or not networking, then we just loaded a previously

src/saveload/extended_ver_sl.cpp

@@ -45,6 +45,7 @@ std::vector<uint32> _sl_xv_discardable_chunk_ids;           ///< list of chunks
 static const uint32 _sl_xv_slxi_chunk_version = 0;          ///< current version os SLXI chunk
 
 const SlxiSubChunkInfo _sl_xv_sub_chunk_infos[] = {
+	{ XSLFI_REVERSE_AT_WAYPOINT,    XSCF_NULL,              1,                                    1, "reverse_at_waypoint",   NULL, NULL, NULL        },
 	{ XSLFI_NULL, XSCF_NULL, 0, 0, NULL, NULL, NULL, NULL },// This is the end marker
 };
 

src/saveload/extended_ver_sl.h

@@ -21,6 +21,7 @@
  */
 enum SlXvFeatureIndex {
 	XSLFI_NULL                          = 0,      ///< Unused value, to indicate that no extended feature test is in use
+	XSLFI_REVERSE_AT_WAYPOINT,                    ///< Reverse at waypoint orders
 
 	XSLFI_SIZE,                                   ///< Total count of features, including null feature
 };

src/saveload/vehicle_sl.cpp

@@ -724,6 +724,7 @@ const SaveLoad *GetVehicleDescription(VehicleType vt)
 		SLE_CONDNULL(2, 2, 19),
 		 SLE_CONDVAR(Train, gv_flags,            SLE_UINT16,                 139, SL_MAX_VERSION),
 		SLE_CONDNULL(11, 2, 143), // old reserved space
+		SLE_CONDVAR_X(Train, reverse_distance,    SLE_UINT16,                   0, SL_MAX_VERSION, SlXvFeatureTest(XSLFTO_AND, XSLFI_REVERSE_AT_WAYPOINT)),
 
 		     SLE_END()
 	};

src/station_cmd.cpp

@@ -3129,6 +3129,11 @@ static VehicleEnterTileStatus VehicleEnter_Station(Vehicle *v, TileIndex tile, i
 {
 	if (v->type == VEH_TRAIN) {
 		StationID station_id = GetStationIndex(tile);
+		if (v->current_order.IsType(OT_GOTO_WAYPOINT) && v->current_order.GetDestination() == station_id && v->current_order.GetWaypointFlags() & OWF_REVERSE) {
+			Train *t = Train::From(v);
+			// reverse at waypoint
+			if (t->reverse_distance == 0) t->reverse_distance = t->gcache.cached_total_length;
+		}
 		if (!v->current_order.ShouldStopAtStation(v, station_id)) return VETSB_CONTINUE;
 		if (!IsRailStation(tile) || !v->IsFrontEngine()) return VETSB_CONTINUE;
 

src/train.h

@@ -102,6 +102,8 @@ struct Train FINAL : public GroundVehicle<Train, VEH_TRAIN> {
 	/** Ticks waiting in front of a signal, ticks being stuck or a counter for forced proceeding through signals. */
 	uint16 wait_counter;
 
+	uint16 reverse_distance;
+
 	/** We don't want GCC to zero our struct! It already is zeroed and has an index! */
 	Train() : GroundVehicleBase() {}
 	/** We want to 'destruct' the right class. */

src/train_cmd.cpp

@@ -624,6 +624,7 @@ static CommandCost CmdBuildRailWagon(TileIndex tile, DoCommandFlag flags, const
 		v->owner = _current_company;
 		v->track = TRACK_BIT_DEPOT;
 		v->vehstatus = VS_HIDDEN | VS_DEFPAL;
+		v->reverse_distance = 0;
 
 		v->SetWagon();
 
@@ -756,6 +757,7 @@ CommandCost CmdBuildRailVehicle(TileIndex tile, DoCommandFlag flags, const Engin
 		v->refit_cap = 0;
 		v->last_station_visited = INVALID_STATION;
 		v->last_loading_station = INVALID_STATION;
+		v->reverse_distance = 0;
 
 		v->engine_type = e->index;
 		v->gcache.first_engine = INVALID_ENGINE; // needs to be set before first callback
@@ -1811,6 +1813,8 @@ void ReverseTrainDirection(Train *v)
 		InvalidateWindowData(WC_VEHICLE_DEPOT, v->tile);
 	}
 
+	v->reverse_distance = 0;
+
 	/* Clear path reservation in front if train is not stuck. */
 	if (!HasBit(v->flags, VRF_TRAIN_STUCK)) FreeTrainTrackReservation(v);
 
@@ -3104,6 +3108,22 @@ bool TrainController(Train *v, Vehicle *nomove, bool reverse)
 	Train *prev;
 	bool direction_changed = false; // has direction of any part changed?
 
+	if (reverse && v->reverse_distance == 1) {
+		goto reverse_train_direction;
+	}
+
+	if (v->reverse_distance > 1) {
+		v->vehstatus |= VS_TRAIN_SLOWING;
+		int target_speed;
+		if (_settings_game.vehicle.train_acceleration_model == AM_REALISTIC) {
+			target_speed = ((v->reverse_distance - 1) * 5) / 2;
+		} else {
+			target_speed = (v->reverse_distance - 1) * 10 - 5;
+		}
+		uint16 spd = max(0, target_speed);
+		if (spd < v->cur_speed) v->cur_speed = spd;
+	}
+
 	/* For every vehicle after and including the given vehicle */
 	for (prev = v->Previous(); v != nomove; prev = v, v = v->Next()) {
 		DiagDirection enterdir = DIAGDIR_BEGIN;
@@ -3118,6 +3138,7 @@ bool TrainController(Train *v, Vehicle *nomove, bool reverse)
 					/* Inside depot */
 					gp.x = v->x_pos;
 					gp.y = v->y_pos;
+					v->reverse_distance = 0;
 				} else {
 					/* Not inside depot */
 
@@ -3354,6 +3375,9 @@ bool TrainController(Train *v, Vehicle *nomove, bool reverse)
 		v->x_pos = gp.x;
 		v->y_pos = gp.y;
 		v->UpdatePosition();
+		if (v->reverse_distance > 1) {
+			v->reverse_distance--;
+		}
 
 		/* update the Z position of the vehicle */
 		int old_z = v->UpdateInclination(gp.new_tile != gp.old_tile, false);

src/vehicle.cpp

@@ -1362,6 +1362,7 @@ void VehicleEnterDepot(Vehicle *v)
 			t->force_proceed = TFP_NONE;
 			ClrBit(t->flags, VRF_TOGGLE_REVERSE);
 			t->ConsistChanged(CCF_ARRANGE);
+			t->reverse_distance = 0;
 			break;
 		}
 

src/widgets/order_widget.h

@@ -29,6 +29,7 @@ enum OrderWidgets {
 	WID_O_SERVICE,                   ///< Select service (at depot).
 	WID_O_EMPTY,                     ///< Placeholder for refit dropdown when not owner.
 	WID_O_REFIT_DROPDOWN,            ///< Open refit options.
+	WID_O_REVERSE,                   ///< Select waypoint reverse type
 	WID_O_COND_VARIABLE,             ///< Choose condition variable.
 	WID_O_COND_COMPARATOR,           ///< Choose condition type.
 	WID_O_COND_VALUE,                ///< Choose condition value.