Add combined normal and shunt aspect signal style flag

docs/newgrf-additions-nml.html

@@ -516,13 +516,20 @@ item (FEAT_GLOBALVARS) {
 	<tr><td>style_lookahead_single_signal_only</td><td>0 or 1</td>
 		<td>
 			Set the look-ahead to single signal only mode for the most recently defined style (defined using the <span class="code">define_style</span> property).<br />
-			This property only makes a difference when the "limit train lookahead to signal aspect" game setting is enabled.<br />
+			This property only makes a difference when the "limit train lookahead to signal aspect" game setting is enabled, or when using a different signal
+			type which uses <span class="code">tyle_combined_normal_shunt</span>.<br />
 			This is similar to <span class="code">style_lookahead_extra_aspects</span> with a value of 0, except the lookahead always ends at the
 			next signal, even if that signal type sets <span class="code">style_no_aspect_increase</span>.<br />
 			If enabled, this property overrides <span class="code">style_lookahead_extra_aspects</span>.<br />
 			This can be used for shunt signals.
 		</td>
 	</tr>
+	<tr><td>style_combined_normal_shunt</td><td>0 or 1</td>
+		<td>
+			Enable functioning as a combined normal aspect and shunt signal for the most recently defined style (defined using the <span class="code">define_style</span> property).<br />
+			When enabled and displaying a shunt aspect, the signal state in the lowest byte of <span class="code">extra_callback_info2</span> will have the value: 0xFF.
+		</td>
+	</tr>
 	<tr><td>style_opposite_side</td><td>0 or 1</td>
 		<td>
 			Set whether signals should be drawn on the opposite side of the track for the most recently defined style (defined using the <span class="code">define_style</span> property).

docs/newgrf-additions.html

@@ -483,7 +483,8 @@
 	<p>This is indicated by the feature name: <font face="monospace">action0_signals_style</font>, version 1</p>
 	<h4 id="signals_style_lookahead_single_signal_only">Set custom signal style train look-ahead to single signal only mode (mappable property: signals_style_lookahead_single_signal_only)</h4>
 	<p>This applies to the most recent custom signal style defined using the <a href="#signals_define_style">signals_define_style</a> property.<br />
-	This property only makes a difference when the "limit train lookahead to signal aspect" game setting is enabled.<br />
+	This property only makes a difference when the "limit train lookahead to signal aspect" game setting is enabled, or when using a different signal
+	type which uses <a href="#signals_style_combined_normal_shunt">signals_style_combined_normal_shunt</a>.<br />
 	This is similar to <a href="#signals_style_lookahead_extra_aspects">signals_style_lookahead_extra_aspects</a> with a value of 0, except the lookahead always ends at the
 	next signal, even if that signal type sets <a href="#signals_style_no_aspect_increase">signals_style_no_aspect_increase</a>.<br />
 	If enabled, this property overrides <a href="#signals_style_lookahead_extra_aspects">signals_style_lookahead_extra_aspects</a>.<br />
@@ -492,6 +493,13 @@
 	The Action 0 Id field is not used, the value is ignored.
 	</p>
 	<p>This is indicated by the feature name: <font face="monospace">action0_signals_style</font>, version 1</p>
+	<h4 id="signals_style_combined_normal_shunt">Set custom signal style combined normal aspect and shunt signal mode (mappable property: signals_style_combined_normal_shunt)</h4>
+	<p>This applies to the most recent custom signal style defined using the <a href="#signals_define_style">signals_define_style</a> property.<br />
+	When enabled and displaying a shunt aspect, the signal state in the lowest byte of variable 0x18 (SS: signal state) will have the value: 0xFF.</p>
+	<p>The property length is 1 byte. 0 is disabled (default). 1 is enabled.<br />
+	The Action 0 Id field is not used, the value is ignored.
+	</p>
+	<p>This is indicated by the feature name: <font face="monospace">action0_signals_style</font>, version 1</p>
 	<h4 id="signals_style_opposite_side">Set custom signal style signal drawn on opposite side (mappable property: signals_style_opposite_side)</h4>
 	<p>This applies to the most recent custom signal style defined using the <a href="#signals_define_style">signals_define_style</a> property.<br />
 	When enabled, signals using this style are drawn on the opposite side of the track.</p>

src/infrastructure.cpp

@@ -356,7 +356,7 @@ void UpdateAllBlockSignals(Owner owner)
 			}
 			if (_extra_aspects > 0 && IsTunnelBridgeSignalSimulationEntrance(tile) && GetTunnelBridgeEntranceSignalState(tile) == SIGNAL_STATE_GREEN) {
 				SetTunnelBridgeEntranceSignalAspect(tile, 0);
-				UpdateAspectDeferred(tile, GetTunnelBridgeEntranceTrackdir(tile));
+				UpdateAspectDeferred(tile, GetTunnelBridgeEntranceTrackdir(tile), false);
 			}
 		}
 	} while (++tile != MapSize());

src/newgrf.cpp

@@ -4289,6 +4289,15 @@ static ChangeInfoResult SignalsChangeInfo(uint id, int numinfo, int prop, const
 				break;
 			}
 
+			case A0RPI_SIGNALS_STYLE_COMBINED_NORMAL_SHUNT: {
+				if (MappedPropertyLengthMismatch(buf, 1, mapping_entry)) break;
+				uint8 value = buf->ReadByte();
+				if (_cur.grffile->current_new_signal_style != nullptr) {
+					SB(_cur.grffile->current_new_signal_style->style_flags, NSSF_COMBINED_NORMAL_SHUNT, 1, (value != 0 ? 1 : 0));
+				}
+				break;
+			}
+
 			default:
 				ret = HandleAction0PropertyDefault(buf, prop);
 				break;

src/newgrf_extension.cpp

@@ -101,6 +101,7 @@ extern const GRFPropertyMapDefinition _grf_action0_remappable_properties[] = {
 	GRFPropertyMapDefinition(GSF_SIGNALS, A0RPI_SIGNALS_STYLE_SEMAPHORE_ENABLED, "signals_style_semaphore_enabled"),
 	GRFPropertyMapDefinition(GSF_SIGNALS, A0RPI_SIGNALS_STYLE_ELECTRIC_ENABLED, "signals_style_electric_enabled"),
 	GRFPropertyMapDefinition(GSF_SIGNALS, A0RPI_SIGNALS_STYLE_OPPOSITE_SIDE, "signals_style_opposite_side"),
+	GRFPropertyMapDefinition(GSF_SIGNALS, A0RPI_SIGNALS_STYLE_COMBINED_NORMAL_SHUNT, "signals_style_combined_normal_shunt"),
 	GRFPropertyMapDefinition(GSF_OBJECTS, A0RPI_OBJECT_USE_LAND_GROUND, "object_use_land_ground"),
 	GRFPropertyMapDefinition(GSF_OBJECTS, A0RPI_OBJECT_EDGE_FOUNDATION_MODE, "object_edge_foundation_mode"),
 	GRFPropertyMapDefinition(GSF_OBJECTS, A0RPI_OBJECT_FLOOD_RESISTANT, "object_flood_resistant"),

src/newgrf_extension.h

@@ -45,6 +45,7 @@ enum Action0RemapPropertyIds {
 	A0RPI_SIGNALS_STYLE_SEMAPHORE_ENABLED,
 	A0RPI_SIGNALS_STYLE_ELECTRIC_ENABLED,
 	A0RPI_SIGNALS_STYLE_OPPOSITE_SIDE,
+	A0RPI_SIGNALS_STYLE_COMBINED_NORMAL_SHUNT,
 	A0RPI_OBJECT_USE_LAND_GROUND,
 	A0RPI_OBJECT_EDGE_FOUNDATION_MODE,
 	A0RPI_OBJECT_FLOOD_RESISTANT,

src/newgrf_newsignals.h

@@ -33,6 +33,7 @@ enum NewSignalStyleFlags {
 	NSSF_LOOKAHEAD_ASPECTS_SET          = 2,
 	NSSF_OPPOSITE_SIDE                  = 3,
 	NSSF_LOOKAHEAD_SINGLE_SIGNAL        = 4,
+	NSSF_COMBINED_NORMAL_SHUNT          = 5,
 };
 
 struct NewSignalStyle {

src/newgrf_railtype.cpp

@@ -15,6 +15,7 @@
 #include "date_func.h"
 #include "depot_base.h"
 #include "town.h"
+#include "signal_func.h"
 
 #include "safeguards.h"
 
@@ -117,10 +118,16 @@ SpriteID GetCustomRailSprite(const RailtypeInfo *rti, TileIndex tile, RailTypeSp
 	return group->GetResult();
 }
 
-inline uint8 RemapAspect(uint8 aspect, uint8 extra_aspects)
+inline uint8 RemapAspect(uint8 aspect, uint8 extra_aspects, uint8 style)
 {
 	if (likely(extra_aspects == 0 || _extra_aspects == 0)) return std::min<uint8>(aspect, 1);
 	if (aspect == 0) return 0;
+	if (style != 0 && HasBit(_signal_style_masks.combined_normal_shunt, style)) {
+		if (aspect == 1) {
+			return 0xFF;
+		}
+		aspect--;
+	}
 	if (aspect >= extra_aspects + 1) return 1;
 	return aspect + 1;
 }
@@ -132,7 +139,7 @@ static PalSpriteID GetRailTypeCustomSignalSprite(const RailtypeInfo *rti, TileIn
 	if (type == SIGTYPE_NO_ENTRY && !HasBit(rti->ctrl_flags, RTCF_NOENTRYSIG)) return { 0, PAL_NONE };
 
 	uint32 param1 = (context == CSSC_GUI) ? 0x10 : 0x00;
-	uint32 param2 = (type << 16) | (var << 8) | RemapAspect(aspect, rti->signal_extra_aspects);
+	uint32 param2 = (type << 16) | (var << 8) | RemapAspect(aspect, rti->signal_extra_aspects, 0);
 	if ((prog != nullptr) && HasBit(rti->ctrl_flags, RTCF_RESTRICTEDSIG)) SetBit(param2, 24);
 	RailTypeResolverObject object(rti, tile, TCX_NORMAL, RTSG_SIGNALS, param1, param2, context, prog);
 
@@ -170,7 +177,7 @@ CustomSignalSpriteResult GetCustomSignalSprite(const RailtypeInfo *rti, TileInde
 		if (!HasBit(grf->new_signal_style_mask, style)) continue;
 
 		uint32 param1 = (context == CSSC_GUI) ? 0x10 : 0x00;
-		uint32 param2 = (type << 16) | (var << 8) | RemapAspect(aspect, grf->new_signal_extra_aspects);
+		uint32 param2 = (type << 16) | (var << 8) | RemapAspect(aspect, grf->new_signal_extra_aspects, style);
 		if ((prog != nullptr) && HasBit(grf->new_signal_ctrl_flags, NSCF_RESTRICTEDSIG)) SetBit(param2, 24);
 		NewSignalsResolverObject object(grf, tile, TCX_NORMAL, param1, param2, context, style, prog);
 

src/pbs.cpp

@@ -88,7 +88,7 @@ bool TryReserveRailTrackdir(TileIndex tile, Trackdir td, bool trigger_stations)
 		MarkSingleSignalDirty(tile, td);
 		if (_extra_aspects > 0) {
 			SetSignalAspect(tile, TrackdirToTrack(td), 0);
-			UpdateAspectDeferred(tile, td);
+			UpdateAspectDeferred(tile, td, true);
 		}
 	}
 	return success;
@@ -667,6 +667,10 @@ static PBSTileInfo FollowReservation(Owner o, RailTypes rts, TileIndex tile, Tra
 					if (HasBit(_signal_style_masks.next_only, signal_style)) {
 						SetBit(signal_flags, TRSLAI_NEXT_ONLY);
 					}
+					if (HasBit(_signal_style_masks.combined_normal_shunt, signal_style)) {
+						SetBit(signal_flags, TRSLAI_COMBINED);
+						UpdateLookaheadCombinedNormalShuntSignalDeferred(tile, trackdir, lookahead->RealEndPosition());
+					}
 					lookahead->AddSignal(signal_speed, 0, z, signal_flags);
 					lookahead->SetNextExtendPositionIfUnset();
 				}
@@ -1011,6 +1015,18 @@ void SetTrainReservationLookaheadEnd(Train *v)
 	for (const TrainReservationLookAheadItem &item : v->lookahead->items) {
 		if (item.end >= v->lookahead->reservation_end_position) break;
 		if (item.type == TRLIT_SIGNAL) {
+			if (HasBit(item.data_aux, TRSLAI_COMBINED_SHUNT)) {
+				/* Combined normal/shunt in shunt mode */
+				allow_skip_no_aspect_inc = false;
+				if (item.start <= threshold) {
+					known_signals_ahead = 1;
+					continue;
+				} else {
+					if (item.start > v->lookahead->lookahead_end_position) v->lookahead->lookahead_end_position = item.start;
+					return;
+				}
+			}
+
 			if (item.start <= threshold) {
 				/* Signal is within visual range */
 				uint8 style = item.data_aux >> 8;
@@ -1090,6 +1106,7 @@ void FillTrainReservationLookAhead(Train *v)
 			}
 			if (!(HasAcrossTunnelBridgeReservation(end) && GetTunnelBridgeExitSignalState(end) == SIGNAL_STATE_GREEN && raw_free_tiles == INT_MAX)) {
 				/* do not attempt to follow through a signalled tunnel/bridge if it is not empty or the far end is not reserved */
+				FlushDeferredDetermineCombineNormalShuntMode(v);
 				SetTrainReservationLookaheadEnd(v);
 				return;
 			}
@@ -1097,6 +1114,7 @@ void FillTrainReservationLookAhead(Train *v)
 	}
 
 	if (IsRailDepotTile(tile) && !GetDepotReservationTrackBits(tile)) {
+		FlushDeferredDetermineCombineNormalShuntMode(v);
 		SetTrainReservationLookaheadEnd(v);
 		return;
 	}
@@ -1131,6 +1149,7 @@ void FillTrainReservationLookAhead(Train *v)
 	v->lookahead->reservation_end_tile = res.tile;
 	v->lookahead->reservation_end_trackdir = res.trackdir;
 
+	FlushDeferredDetermineCombineNormalShuntMode(v);
 	SetTrainReservationLookaheadEnd(v);
 }
 

src/pbs.h

@@ -61,6 +61,8 @@ enum TrainReservationLookAheadItemType : byte {
 enum TrainReservationSignalLookAheadItemFlags {
 	TRSLAI_NO_ASPECT_INC   = 0,           ///< This signal does not increase the signal aspect (e.g. banner repeater)
 	TRSLAI_NEXT_ONLY       = 1,           ///< This signal only permits lookahead up to the next physical signal, even if that has TRSLAI_NO_ASPECT_INC (e.g. shunt)
+	TRSLAI_COMBINED        = 2,           ///< This signal is a combined normal/shunt signal, special handling
+	TRSLAI_COMBINED_SHUNT  = 3,           ///< This signal is a combined normal/shunt signal, in shunt mode
 };
 
 struct TrainReservationLookAheadItem {

src/rail_cmd.cpp

@@ -1434,7 +1434,7 @@ static void SetupBridgeTunnelSignalSimulation(TileIndex entrance, TileIndex exit
 	SetTunnelBridgeSignalSimulationExit(exit);
 	if (_extra_aspects > 0) {
 		SetTunnelBridgeEntranceSignalAspect(entrance, 0);
-		UpdateAspectDeferred(entrance, GetTunnelBridgeEntranceTrackdir(entrance));
+		UpdateAspectDeferred(entrance, GetTunnelBridgeEntranceTrackdir(entrance), false);
 	}
 }
 
@@ -1583,7 +1583,7 @@ CommandCost CmdBuildSingleSignal(TileIndex tile, DoCommandFlag flags, uint32 p1,
 			SetTunnelBridgeSignalSimulationExit(t);
 			if (_extra_aspects > 0) {
 				SetTunnelBridgeEntranceSignalAspect(t, 0);
-				UpdateAspectDeferred(t, GetTunnelBridgeEntranceTrackdir(t));
+				UpdateAspectDeferred(t, GetTunnelBridgeEntranceTrackdir(t), false);
 			}
 		};
 

src/signal.cpp

@@ -25,6 +25,7 @@
 #include "newgrf_newsignals.h"
 #include "core/checksum_func.hpp"
 #include "core/hash_func.hpp"
+#include "pathfinder/follow_track.hpp"
 
 #include "safeguards.h"
 
@@ -367,7 +368,7 @@ static SigInfo ExploreSegment(Owner owner)
 						if (HasSignalOnTrackdir(tile, reversedir)) {
 							if (IsPbsSignalNonExtended(sig)) {
 								info.flags |= SF_PBS;
-								if (_extra_aspects > 0 && GetSignalStateByTrackdir(tile, reversedir) == SIGNAL_STATE_GREEN) {
+								if (_extra_aspects > 0 && GetSignalStateByTrackdir(tile, reversedir) == SIGNAL_STATE_GREEN && !IsRailSpecialSignalAspect(tile, track)) {
 									_tbpset.Add(tile, reversedir);
 								}
 							} else if (!_tbuset.Add(tile, reversedir)) {
@@ -778,7 +779,7 @@ static void UpdateSignalsAroundSegment(SigInfo info)
 
 		/* don't change signal state if tile is reserved in realistic braking mode */
 		if ((_settings_game.vehicle.train_braking_model == TBM_REALISTIC && HasBit(GetRailReservationTrackBits(tile), track))) {
-			if (_extra_aspects > 0 && GetSignalStateByTrackdir(tile, trackdir) == SIGNAL_STATE_GREEN) {
+			if (_extra_aspects > 0 && GetSignalStateByTrackdir(tile, trackdir) == SIGNAL_STATE_GREEN && !IsRailSpecialSignalAspect(tile, track)) {
 				uint8 aspect = GetForwardAspectAndIncrement(info, tile, trackdir);
 				uint8 old_aspect = GetSignalAspect(tile, track);
 				if (aspect != old_aspect) {
@@ -1263,7 +1264,14 @@ uint8 GetSignalAspectGeneric(TileIndex tile, Trackdir trackdir, bool check_non_i
 
 void AdjustSignalAspectIfNonIncStyleIntl(TileIndex tile, Track track, uint8 &aspect)
 {
-	if (IsTileType(tile, MP_RAILWAY) && HasBit(_signal_style_masks.non_aspect_inc, GetSignalStyle(tile, track))) aspect--;
+	if (IsTileType(tile, MP_RAILWAY)) {
+		uint8 style = GetSignalStyle(tile, track);
+		if (HasBit(_signal_style_masks.combined_normal_shunt, style)) {
+			aspect--;
+			if (aspect == 0) return;
+		}
+		if (HasBit(_signal_style_masks.non_aspect_inc, style)) aspect--;
+	}
 }
 
 static void RefreshBridgeOnExitAspectChange(TileIndex entrance, TileIndex exit)
@@ -1282,6 +1290,11 @@ static void RefreshBridgeOnExitAspectChange(TileIndex entrance, TileIndex exit)
 	}
 }
 
+static inline bool IsRailCombinedNormalShuntSignalStyle(TileIndex tile, Track track)
+{
+	return _signal_style_masks.combined_normal_shunt != 0 && HasBit(_signal_style_masks.combined_normal_shunt, GetSignalStyle(tile, track));
+}
+
 void PropagateAspectChange(TileIndex tile, Trackdir trackdir, uint8 aspect)
 {
 	AdjustSignalAspectIfNonIncStyle(tile, TrackdirToTrack(trackdir), aspect);
@@ -1330,7 +1343,14 @@ void PropagateAspectChange(TileIndex tile, Trackdir trackdir, uint8 aspect)
 
 						if (HasSignalOnTrackdir(tile, reversedir)) {
 							if (GetSignalStateByTrackdir(tile, reversedir) == SIGNAL_STATE_RED) return;
-							if (GetSignalAspect(tile, track) == aspect) return; // aspect already correct
+							bool combined_mode = IsRailCombinedNormalShuntSignalStyle(tile, track);
+							const uint8 current_aspect = GetSignalAspect(tile, track);
+							if (combined_mode && current_aspect == 1) {
+								/* Don't change special combined_normal_shunt aspect */
+								return;
+							}
+							if (combined_mode && aspect > 0) aspect = std::min<uint8>(aspect + 1, 7);
+							if (current_aspect == aspect) return; // aspect already correct
 							SetSignalAspect(tile, track, aspect);
 							MarkSingleSignalDirty(tile, reversedir);
 							AdjustSignalAspectIfNonIncStyle(tile, TrackdirToTrack(trackdir), aspect);
@@ -1426,12 +1446,29 @@ void PropagateAspectChange(TileIndex tile, Trackdir trackdir, uint8 aspect)
 }
 
 static std::vector<std::pair<TileIndex, Trackdir>> _deferred_aspect_updates;
+static std::vector<std::pair<TileIndex, Trackdir>> _deferred_determine_combined_normal_shunt_mode;
 
-void UpdateAspectDeferred(TileIndex tile, Trackdir trackdir)
+struct DeferredLookaheadCombinedNormalShuntModeItem {
+	TileIndex tile;
+	Trackdir trackdir;
+	int lookahead_position;
+};
+static std::vector<DeferredLookaheadCombinedNormalShuntModeItem> _deferred_lookahead_combined_normal_shunt_mode;
+
+void UpdateAspectDeferred(TileIndex tile, Trackdir trackdir, bool check_combined_normal_aspect)
 {
+	if (check_combined_normal_aspect && IsRailCombinedNormalShuntSignalStyle(tile, TrackdirToTrack(trackdir)) &&
+			_settings_game.vehicle.train_braking_model == TBM_REALISTIC) {
+		_deferred_determine_combined_normal_shunt_mode.push_back({ tile, trackdir });
+	}
 	_deferred_aspect_updates.push_back({ tile, trackdir });
 }
 
+void UpdateLookaheadCombinedNormalShuntSignalDeferred(TileIndex tile, Trackdir trackdir, int lookahead_position)
+{
+	_deferred_lookahead_combined_normal_shunt_mode.push_back({ tile, trackdir, lookahead_position });
+}
+
 void FlushDeferredAspectUpdates()
 {
 	/* Iterate in reverse order to reduce backtracking when updating the aspects of a new reservation */
@@ -1441,7 +1478,7 @@ void FlushDeferredAspectUpdates()
 		switch (GetTileType(tile)) {
 			case MP_RAILWAY:
 				if (HasSignalOnTrackdir(tile, trackdir) && GetSignalStateByTrackdir(tile, trackdir) == SIGNAL_STATE_GREEN && GetSignalAspect(tile, TrackdirToTrack(trackdir)) == 0) {
-					uint8 aspect = GetForwardAspectFollowingTrackAndIncrement(tile, trackdir);
+					uint8 aspect = GetForwardAspectFollowingTrackAndIncrement(tile, trackdir, IsRailCombinedNormalShuntSignalStyle(tile, TrackdirToTrack(trackdir)));
 					SetSignalAspect(tile, TrackdirToTrack(trackdir), aspect);
 					PropagateAspectChange(tile, trackdir, aspect);
 				}
@@ -1469,6 +1506,68 @@ void FlushDeferredAspectUpdates()
 	_deferred_aspect_updates.clear();
 }
 
+void DetermineCombineNormalShuntModeWithLookahead(Train *v, TileIndex tile, Trackdir trackdir, int lookahead_position)
+{
+	size_t count = v->lookahead->items.size();
+	for (size_t i = 0; i < count; i++) {
+		TrainReservationLookAheadItem &item = v->lookahead->items[i];
+		if (item.start == lookahead_position && item.type == TRLIT_SIGNAL && HasBit(item.data_aux, TRSLAI_COMBINED)) {
+			container_unordered_remove(_deferred_determine_combined_normal_shunt_mode, std::pair<TileIndex, Trackdir>({ tile, trackdir }));
+
+			for (size_t j = i + 1; j < count; j++) {
+				const TrainReservationLookAheadItem &ahead = v->lookahead->items[j];
+				if (ahead.type == TRLIT_SIGNAL) {
+					if (HasBit(item.data_aux, TRSLAI_COMBINED)) return;
+					if (!HasBit(item.data_aux, TRSLAI_NO_ASPECT_INC) && !HasBit(item.data_aux, TRSLAI_NEXT_ONLY)) return;
+				}
+			}
+
+			if (IsRailDepotTile(v->lookahead->reservation_end_tile) || IsTileType(v->lookahead->reservation_end_tile, MP_TUNNELBRIDGE)) return;
+
+			CFollowTrackRail ft(v);
+			if (ft.Follow(v->lookahead->reservation_end_tile, v->lookahead->reservation_end_trackdir)) {
+				if (KillFirstBit(ft.m_new_td_bits) != TRACKDIR_BIT_NONE) {
+					/* reached a junction tile, shouldn't be reached, just assume normal route */
+					return;
+				}
+
+				TileIndex new_tile = ft.m_new_tile;
+				Trackdir new_trackdir = FindFirstTrackdir(ft.m_new_td_bits);
+
+				if (!(IsTileType(new_tile, MP_RAILWAY) && HasSignalOnTrackdir(new_tile, new_trackdir) && !IsNoEntrySignal(new_tile, TrackdirToTrack(new_trackdir)) &&
+						HasBit(_signal_style_masks.next_only, GetSignalStyle(new_tile, TrackdirToTrack(new_trackdir))))) {
+					/* Didn't find a shunt signal at the end of the reservation */
+					return;
+				}
+			} else {
+				/* end of line */
+				return;
+			}
+
+			/* shunt mode */
+			SetSignalAspect(tile, TrackdirToTrack(trackdir), 1);
+			SetBit(item.data_aux, TRSLAI_COMBINED_SHUNT);
+			return;
+		}
+	}
+}
+
+void FlushDeferredDetermineCombineNormalShuntMode(Train *v)
+{
+	for (const auto &iter : _deferred_lookahead_combined_normal_shunt_mode) {
+		DetermineCombineNormalShuntModeWithLookahead(v, iter.tile, iter.trackdir, iter.lookahead_position);
+	}
+	_deferred_lookahead_combined_normal_shunt_mode.clear();
+
+	for (const auto &iter : _deferred_determine_combined_normal_shunt_mode) {
+		TileIndex tile = iter.first;
+		Trackdir trackdir = iter.second;
+		/* Reservation with no associated lookahead, default to a shunt route */
+		SetSignalAspect(tile, TrackdirToTrack(trackdir), 1);
+	}
+	_deferred_determine_combined_normal_shunt_mode.clear();
+}
+
 void UpdateAllSignalAspects()
 {
 	for (TileIndex tile = 0; tile != MapSize(); ++tile) {
@@ -1479,8 +1578,8 @@ void UpdateAllSignalAspects()
 				if (HasSignalOnTrack(tile, track)) {
 					Trackdir trackdir = TrackToTrackdir(track);
 					if (!HasSignalOnTrackdir(tile, trackdir)) trackdir = ReverseTrackdir(trackdir);
-					if (GetSignalStateByTrackdir(tile, trackdir) == SIGNAL_STATE_GREEN) {
+					if (GetSignalStateByTrackdir(tile, trackdir) == SIGNAL_STATE_GREEN && !IsRailSpecialSignalAspect(tile, track)) {
-						uint8 aspect = GetForwardAspectFollowingTrackAndIncrement(tile, trackdir);
+						uint8 aspect = GetForwardAspectFollowingTrackAndIncrement(tile, trackdir, IsRailCombinedNormalShuntSignalStyle(tile, track));
 						SetSignalAspect(tile, track, aspect);
 						PropagateAspectChange(tile, trackdir, aspect);
 					}
@@ -1613,6 +1712,12 @@ static bool DetermineExtraAspectsVariable()
 		if (HasBit(_new_signal_styles[i].style_flags, NSSF_OPPOSITE_SIDE)) {
 			SetBit(_signal_style_masks.signal_opposite_side, i + 1);
 		}
+		if (HasBit(_new_signal_styles[i].style_flags, NSSF_COMBINED_NORMAL_SHUNT)) {
+			SetBit(_signal_style_masks.combined_normal_shunt, i + 1);
+			SetBit(_signal_style_masks.no_tunnel_bridge, i + 1);
+			_new_signal_styles[i].electric_mask &= (1 << SIGTYPE_PBS) | (1 << SIGTYPE_PBS_ONEWAY) | (1 << SIGTYPE_NO_ENTRY);
+			_new_signal_styles[i].semaphore_mask &= (1 << SIGTYPE_PBS) | (1 << SIGTYPE_PBS_ONEWAY) | (1 << SIGTYPE_NO_ENTRY);
+		}
 	}
 	for (uint i = _num_new_signal_styles; i < MAX_NEW_SIGNAL_STYLES; i++) {
 		_new_signal_styles[i].lookahead_extra_aspects = new_extra_aspects;
@@ -1665,6 +1770,12 @@ void InitialiseExtraAspectsVariable()
 	DetermineExtraAspectsVariable();
 }
 
+bool IsRailSpecialSignalAspect(TileIndex tile, Track track)
+{
+	return _signal_style_masks.combined_normal_shunt != 0 && GetSignalAspect(tile, track) == 1 &&
+			HasBit(_signal_style_masks.combined_normal_shunt, GetSignalStyle(tile, track));
+}
+
 void UpdateSignalReserveThroughBit(TileIndex tile, Track track, bool update_signal)
 {
 	bool reserve_through = false;

src/signal_func.h

@@ -33,6 +33,7 @@ struct SignalStyleMasks {
 	uint16 always_reserve_through = 0;
 	uint16 no_tunnel_bridge = 0;
 	uint16 signal_opposite_side = 0;
+	uint16 combined_normal_shunt = 0;
 };
 extern SignalStyleMasks _signal_style_masks;
 
@@ -188,21 +189,24 @@ void UpdateSignalsInBufferIfOwnerNotAddable(Owner owner);
 uint8 GetForwardAspectFollowingTrack(TileIndex tile, Trackdir trackdir);
 uint8 GetSignalAspectGeneric(TileIndex tile, Trackdir trackdir, bool check_non_inc_style);
 void PropagateAspectChange(TileIndex tile, Trackdir trackdir, uint8 aspect);
-void UpdateAspectDeferred(TileIndex tile, Trackdir trackdir);
+void UpdateAspectDeferred(TileIndex tile, Trackdir trackdir, bool check_combined_normal_aspect);
+void UpdateLookaheadCombinedNormalShuntSignalDeferred(TileIndex tile, Trackdir trackdir, int lookahead_position);
 void FlushDeferredAspectUpdates();
+void FlushDeferredDetermineCombineNormalShuntMode(Train *v);
 void UpdateAllSignalAspects();
 void UpdateExtraAspectsVariable();
 void InitialiseExtraAspectsVariable();
+bool IsRailSpecialSignalAspect(TileIndex tile, Track track);
 
 inline void AdjustSignalAspectIfNonIncStyle(TileIndex tile, Track track, uint8 &aspect)
 {
 	extern void AdjustSignalAspectIfNonIncStyleIntl(TileIndex tile, Track track, uint8 &aspect);
-	if (aspect > 0 && _signal_style_masks.non_aspect_inc != 0) AdjustSignalAspectIfNonIncStyleIntl(tile, track, aspect);
+	if (aspect > 0 && (_signal_style_masks.non_aspect_inc != 0 || _signal_style_masks.combined_normal_shunt != 0)) AdjustSignalAspectIfNonIncStyleIntl(tile, track, aspect);
 }
 
-inline uint8 GetForwardAspectFollowingTrackAndIncrement(TileIndex tile, Trackdir trackdir)
+inline uint8 GetForwardAspectFollowingTrackAndIncrement(TileIndex tile, Trackdir trackdir, bool combined_normal_mode = false)
 {
-	return std::min<uint8>(GetForwardAspectFollowingTrack(tile, trackdir) + 1, GetMaximumSignalAspect());
+	return std::min<uint8>(GetForwardAspectFollowingTrack(tile, trackdir) + (combined_normal_mode ? 2 : 1), GetMaximumSignalAspect());
 }
 
 void UpdateSignalReserveThroughBit(TileIndex tile, Track track, bool update_signal);

src/table/newgrf_debug_data.h

@@ -279,6 +279,8 @@ class NIHVehicle : public NIHelper {
 							b += seprintf(b, lastof(buffer), "signal: target speed: %u, style: %u, flags:", item.data_id, item.data_aux >> 8);
 							if (HasBit(item.data_aux, TRSLAI_NO_ASPECT_INC)) b += seprintf(b, lastof(buffer), "n");
 							if (HasBit(item.data_aux, TRSLAI_NEXT_ONLY)) b += seprintf(b, lastof(buffer), "s");
+							if (HasBit(item.data_aux, TRSLAI_COMBINED)) b += seprintf(b, lastof(buffer), "c");
+							if (HasBit(item.data_aux, TRSLAI_COMBINED_SHUNT)) b += seprintf(b, lastof(buffer), "X");
 							if (_settings_game.vehicle.realistic_braking_aspect_limited == TRBALM_ON && l.lookahead_end_position == item.start) {
 								b += seprintf(b, lastof(buffer), ", lookahead end");
 								print_braking_speed(item.start, 0, item.z_pos);

src/train_cmd.cpp

@@ -3454,7 +3454,7 @@ static void SetTunnelBridgeEntranceSignalGreen(TileIndex tile)
 		MarkTunnelBridgeSignalDirty(tile, false);
 		if (_extra_aspects > 0) {
 			SetTunnelBridgeEntranceSignalAspect(tile, 0);
-			UpdateAspectDeferred(tile, GetTunnelBridgeEntranceTrackdir(tile));
+			UpdateAspectDeferred(tile, GetTunnelBridgeEntranceTrackdir(tile), false);
 		}
 	} else if (_extra_aspects > 0) {
 		UpdateTunnelBridgeEntranceSignalAspect(tile);
@@ -4086,6 +4086,7 @@ static TileIndex CheckLongReservePbsTunnelBridgeOnTrackdir(Train* v, TileIndex t
 			} else {
 				raw_free_tiles = GetAvailableFreeTilesInSignalledTunnelBridgeWithStartOffset(tile, end, v->lookahead->tunnel_bridge_reserved_tiles + 1);
 				ApplyAvailableFreeTunnelBridgeTiles(v->lookahead.get(), raw_free_tiles, tile, end);
+				FlushDeferredDetermineCombineNormalShuntMode(v);
 				SetTrainReservationLookaheadEnd(v);
 			}
 		} else {
@@ -4156,7 +4157,7 @@ static void TryLongReserveChooseTrainTrack(Train *v, TileIndex tile, Trackdir td
 				} else {
 					if (_extra_aspects > 0) {
 						SetTunnelBridgeExitSignalAspect(exit_tile, 0);
-						UpdateAspectDeferred(exit_tile, GetTunnelBridgeExitTrackdir(exit_tile));
+						UpdateAspectDeferred(exit_tile, GetTunnelBridgeExitTrackdir(exit_tile), false);
 					}
 					MarkTileDirtyByTile(exit_tile, VMDF_NOT_MAP_MODE);
 				}
@@ -4250,7 +4251,7 @@ static Track ChooseTrainTrack(Train *v, TileIndex tile, DiagDirection enterdir,
 			SetSignalStateByTrackdir(tile, changed_signal, SIGNAL_STATE_GREEN);
 			if (_extra_aspects > 0) {
 				SetSignalAspect(tile, track, 0);
-				UpdateAspectDeferred(tile, changed_signal);
+				UpdateAspectDeferred(tile, changed_signal, true);
 			}
 		} else if (!do_track_reservation) {
 			return track;
@@ -5141,7 +5142,7 @@ static bool CheckTrainStayInWormHolePathReserve(Train *t, TileIndex tile)
 			if (ok) {
 				if (_extra_aspects > 0) {
 					SetTunnelBridgeExitSignalAspect(tile, 0);
-					UpdateAspectDeferred(tile, GetTunnelBridgeExitTrackdir(tile));
+					UpdateAspectDeferred(tile, GetTunnelBridgeExitTrackdir(tile), false);
 				}
 				mark_dirty = true;
 				if (t->lookahead->reservation_end_tile == veh_orig_tile && t->lookahead->reservation_end_position - t->lookahead->current_position <= (int)TILE_SIZE) {
@@ -5186,7 +5187,7 @@ static bool CheckTrainStayInWormHolePathReserve(Train *t, TileIndex tile)
 		SetTunnelBridgeExitSignalState(tile, SIGNAL_STATE_GREEN);
 		if (_extra_aspects > 0) {
 			SetTunnelBridgeExitSignalAspect(tile, 0);
-			UpdateAspectDeferred(tile, GetTunnelBridgeExitTrackdir(tile));
+			UpdateAspectDeferred(tile, GetTunnelBridgeExitTrackdir(tile), false);
 		}
 		mark_dirty = true;
 	}