Add signal style flag for drawing on the opposite side

docs/newgrf-additions-nml.html

@@ -512,6 +512,11 @@ item (FEAT_GLOBALVARS) {
 			The value is clamped to be less than or equal to the value set in the <span class="code">extra_aspects</span> property.
 		</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).
+		</td>
+	</tr>
 	<tr><td>no_default_style</td><td>0 or 1</td>
 		<td>
 			When enabled, custom signal graphics from this GRF are only used for custom signal styles, not the default style

docs/newgrf-additions.html

@@ -480,6 +480,13 @@
 	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_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>
+	<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_no_default_style">Set whether custom signal sprites should not be used for the default signal style (mappable property: signals_no_default_style)</h4>
 	<p>This applies to <a href="#a3signals_custom_signal_sprites">Action 2/3 Signals (Feature 0E) custom signal sprites</a> for this GRF.<br />
 	When enabled, this GRF is not used for the default signal style, it is only used for custom signal styles defined with <a href="#signals_define_style">signals_define_style</a>.</p>

src/newgrf.cpp

@@ -4271,6 +4271,15 @@ static ChangeInfoResult SignalsChangeInfo(uint id, int numinfo, int prop, const
 				break;
 			}
 
+			case A0RPI_SIGNALS_STYLE_OPPOSITE_SIDE: {
+				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_OPPOSITE_SIDE, 1, (value != 0 ? 1 : 0));
+				}
+				break;
+			}
+
 			default:
 				ret = HandleAction0PropertyDefault(buf, prop);
 				break;

src/newgrf_extension.cpp

@@ -99,6 +99,7 @@ extern const GRFPropertyMapDefinition _grf_action0_remappable_properties[] = {
 	GRFPropertyMapDefinition(GSF_SIGNALS, A0RPI_SIGNALS_STYLE_LOOKAHEAD_EXTRA_ASPECTS, "signals_style_lookahead_extra_aspects"),
 	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_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

@@ -43,6 +43,7 @@ enum Action0RemapPropertyIds {
 	A0RPI_SIGNALS_STYLE_LOOKAHEAD_EXTRA_ASPECTS,
 	A0RPI_SIGNALS_STYLE_SEMAPHORE_ENABLED,
 	A0RPI_SIGNALS_STYLE_ELECTRIC_ENABLED,
+	A0RPI_SIGNALS_STYLE_OPPOSITE_SIDE,
 	A0RPI_OBJECT_USE_LAND_GROUND,
 	A0RPI_OBJECT_EDGE_FOUNDATION_MODE,
 	A0RPI_OBJECT_FLOOD_RESISTANT,

src/newgrf_newsignals.h

@@ -28,6 +28,7 @@ enum NewSignalStyleFlags {
 	NSSF_NO_ASPECT_INC                  = 0,
 	NSSF_ALWAYS_RESERVE_THROUGH         = 1,
 	NSSF_LOOKAHEAD_ASPECTS_SET          = 2,
+	NSSF_OPPOSITE_SIDE                  = 3,
 };
 
 struct NewSignalStyle {

src/rail.h

@@ -479,7 +479,7 @@ static inline Money SignalMaintenanceCost(uint32 num)
 }
 
 void MarkSingleSignalDirty(TileIndex tile, Trackdir td);
-void MarkSingleSignalDirtyAtZ(TileIndex tile, Trackdir td, uint z);
+void MarkSingleSignalDirtyAtZ(TileIndex tile, Trackdir td, bool opposite_side, uint z);
 
 void DrawTrainDepotSprite(int x, int y, int image, RailType railtype);
 int TicksToLeaveDepot(const Train *v);

src/rail_cmd.cpp

@@ -2763,7 +2763,7 @@ static uint GetSaveSlopeZ(uint x, uint y, Track track)
 	return GetSlopePixelZ(x, y);
 }
 
-static void GetSignalXY(TileIndex tile, uint pos, uint &x, uint &y)
+static void GetSignalXY(TileIndex tile, uint pos, bool opposite, uint &x, uint &y)
 {
 	bool side;
 	switch (_settings_game.construction.train_signal_side) {
@@ -2771,6 +2771,7 @@ static void GetSignalXY(TileIndex tile, uint pos, uint &x, uint &y)
 		case 2:  side = true;                                  break; // right
 		default: side = _settings_game.vehicle.road_side != 0; break; // driving side
 	}
+	side ^= opposite;
 	static const Point SignalPositions[2][12] = {
 		{ // Signals on the left side
 		/*  LEFT      LEFT      RIGHT     RIGHT     UPPER     UPPER */
@@ -2796,8 +2797,25 @@ void DrawSingleSignal(TileIndex tile, const RailtypeInfo *rti, Track track, Sign
 
 	if (type == SIGTYPE_NO_ENTRY) pos ^= 1;
 
+	uint8 style = 0;
+	if (_num_new_signal_styles > 0) {
+		switch (context) {
+			case CSSC_TRACK:
+				style = GetSignalStyle(tile, track);
+				break;
+
+			case CSSC_TUNNEL_BRIDGE_ENTRANCE:
+			case CSSC_TUNNEL_BRIDGE_EXIT:
+				style = GetTunnelBridgeSignalStyle(tile);
+				break;
+
+			default:
+				break;
+		}
+	}
+
 	uint x, y;
-	GetSignalXY(tile, pos, x, y);
+	GetSignalXY(tile, pos, HasBit(_signal_opposite_side_style_mask, style), x, y);
 
 	uint8 aspect;
 	if (condition == SIGNAL_STATE_GREEN) {
@@ -2824,23 +2842,6 @@ void DrawSingleSignal(TileIndex tile, const RailtypeInfo *rti, Track track, Sign
 		aspect = 0;
 	}
 
-	uint8 style = 0;
-	if (_num_new_signal_styles > 0) {
-		switch (context) {
-			case CSSC_TRACK:
-				style = GetSignalStyle(tile, track);
-				break;
-
-			case CSSC_TUNNEL_BRIDGE_ENTRANCE:
-			case CSSC_TUNNEL_BRIDGE_EXIT:
-				style = GetTunnelBridgeSignalStyle(tile);
-				break;
-
-			default:
-				break;
-		}
-	}
-
 	const CustomSignalSpriteResult result = GetCustomSignalSprite(rti, tile, type, variant, aspect, context, style, prog);
 	SpriteID sprite = result.sprite.sprite;
 	PaletteID pal = PAL_NONE;
@@ -2926,7 +2927,7 @@ static void DrawSingleSignal(TileIndex tile, const RailtypeInfo *rti, Track trac
 }
 
 template <typename F>
-void MarkSingleSignalDirtyIntl(TileIndex tile, Trackdir td, F get_z)
+void MarkSingleSignalDirtyIntl(TileIndex tile, Trackdir td, bool opposite, F get_z)
 {
 	static const uint8 trackdir_to_pos[TRACKDIR_END] = {
 		8,  // TRACKDIR_X_NE
@@ -2948,7 +2949,7 @@ void MarkSingleSignalDirtyIntl(TileIndex tile, Trackdir td, F get_z)
 	};
 
 	uint x, y;
-	GetSignalXY(tile, trackdir_to_pos[td], x, y);
+	GetSignalXY(tile, trackdir_to_pos[td], opposite, x, y);
 	Point pt = RemapCoords(x, y, get_z(x, y));
 	MarkAllViewportsDirty(
 			pt.x - SIGNAL_DIRTY_LEFT,
@@ -2965,15 +2966,18 @@ void MarkSingleSignalDirty(TileIndex tile, Trackdir td)
 		MarkTileDirtyByTile(tile, VMDF_NOT_MAP_MODE);
 		return;
 	}
-
+	bool opposite = false;
-	MarkSingleSignalDirtyIntl(tile, td, [td](uint x, uint y) -> uint {
+	if (_signal_opposite_side_style_mask != 0) {
+		opposite = HasBit(_signal_opposite_side_style_mask, GetSignalStyleGeneric(tile, TrackdirToTrack(td)));
+	}
+	MarkSingleSignalDirtyIntl(tile, td, opposite, [td](uint x, uint y) -> uint {
 		return GetSaveSlopeZ(x, y, TrackdirToTrack(td));
 	});
 }
 
-void MarkSingleSignalDirtyAtZ(TileIndex tile, Trackdir td, uint z)
+void MarkSingleSignalDirtyAtZ(TileIndex tile, Trackdir td, bool opposite_side, uint z)
 {
-	MarkSingleSignalDirtyIntl(tile, td, [z](uint x, uint y) -> uint {
+	MarkSingleSignalDirtyIntl(tile, td, opposite_side, [z](uint x, uint y) -> uint {
 		return z;
 	});
 }

src/rail_map.h

@@ -409,6 +409,18 @@ static inline uint8 GetSignalStyle(TileIndex t, Track track)
 	return GB(_me[t].m6, pos, 4);
 }
 
+static inline uint8 GetSignalStyleGeneric(TileIndex t, Track track)
+{
+	switch (GetTileType(t)) {
+		case MP_RAILWAY:
+			return GetSignalStyle(t, track);
+		case MP_TUNNELBRIDGE:
+			return GetTunnelBridgeSignalStyle(t);
+		default:
+			return 0;
+	}
+}
+
 static inline void SetSignalStyle(TileIndex t, Track track, uint8 style)
 {
 	assert_tile(GetRailTileType(t) == RAIL_TILE_SIGNALS, t);

src/signal.cpp

@@ -33,6 +33,7 @@ uint64 _aspect_cfg_hash = 0;
 uint16 _non_aspect_inc_style_mask = 0;
 uint16 _always_reserve_through_style_mask = 0;
 uint16 _no_tunnel_bridge_style_mask = 0;
+uint16 _signal_opposite_side_style_mask = 0;
 bool _signal_sprite_oversized = false;
 
 /// List of signals dependent upon this one
@@ -1513,6 +1514,7 @@ static bool DetermineExtraAspectsVariable()
 	_non_aspect_inc_style_mask = 0;
 	_no_tunnel_bridge_style_mask = 0;
 	_always_reserve_through_style_mask = 0;
+	_signal_opposite_side_style_mask = 0;
 
 	if (_settings_game.vehicle.train_braking_model == TBM_REALISTIC) {
 		for (RailType r = RAILTYPE_BEGIN; r != RAILTYPE_END; r++) {
@@ -1536,6 +1538,9 @@ static bool DetermineExtraAspectsVariable()
 			} else {
 				_new_signal_styles[i].lookahead_extra_aspects = _new_signal_styles[i].grffile->new_signal_extra_aspects;
 			}
+			if (HasBit(_new_signal_styles[i].style_flags, NSSF_OPPOSITE_SIDE)) {
+				SetBit(_signal_opposite_side_style_mask, i + 1);
+			}
 		}
 		for (uint i = _num_new_signal_styles; i < MAX_NEW_SIGNAL_STYLES; i++) {
 			_new_signal_styles[i].lookahead_extra_aspects = new_extra_aspects;

src/signal_func.h

@@ -24,6 +24,7 @@ extern uint64 _aspect_cfg_hash;
 extern uint16 _non_aspect_inc_style_mask;
 extern uint16 _always_reserve_through_style_mask;
 extern uint16 _no_tunnel_bridge_style_mask;
+extern uint16 _signal_opposite_side_style_mask;
 extern bool _signal_sprite_oversized;
 
 /**

src/tunnelbridge_cmd.cpp

@@ -1729,9 +1729,12 @@ static void DrawBridgeRoadBits(TileIndex head_tile, int x, int y, int z, int off
 
 static void DrawTunnelBridgeRampSingleSignal(const TileInfo *ti, bool is_green, uint position, SignalType type, bool show_exit)
 {
-	bool side = (_settings_game.vehicle.road_side != 0) &&_settings_game.construction.train_signal_side;
+	bool side = (_settings_game.vehicle.road_side != 0) && _settings_game.construction.train_signal_side;
 	DiagDirection dir = GetTunnelBridgeDirection(ti->tile);
 
+	uint8 style = GetTunnelBridgeSignalStyle(ti->tile);
+	side ^= HasBit(_signal_opposite_side_style_mask, style);
+
 	static const Point SignalPositions[2][4] = {
 		{   /*  X         X         Y         Y     Signals on the left side */
 			{13,  3}, { 2, 13}, { 3,  4}, {13, 14}
@@ -1761,7 +1764,7 @@ static void DrawTunnelBridgeRampSingleSignal(const TileInfo *ti, bool is_green,
 	}
 	bool show_restricted = IsTunnelBridgeRestrictedSignal(ti->tile);
 	const TraceRestrictProgram *prog = show_restricted ? GetExistingTraceRestrictProgram(ti->tile, FindFirstTrack(GetAcrossTunnelBridgeTrackBits(ti->tile))) : nullptr;
-	const CustomSignalSpriteResult result = GetCustomSignalSprite(rti, ti->tile, type, variant, aspect, show_exit ? CSSC_TUNNEL_BRIDGE_EXIT : CSSC_TUNNEL_BRIDGE_ENTRANCE, GetTunnelBridgeSignalStyle(ti->tile), prog);
+	const CustomSignalSpriteResult result = GetCustomSignalSprite(rti, ti->tile, type, variant, aspect, show_exit ? CSSC_TUNNEL_BRIDGE_EXIT : CSSC_TUNNEL_BRIDGE_ENTRANCE, style, prog);
 	PalSpriteID sprite = result.sprite;
 	bool is_custom_sprite = (sprite.sprite != 0);
 
@@ -1827,9 +1830,10 @@ static void DrawTunnelBridgeRampSignal(const TileInfo *ti)
 	}
 }
 
-static void GetBridgeSignalXY(TileIndex tile, DiagDirection bridge_direction, uint &position, uint &x, uint &y)
+static void GetBridgeSignalXY(TileIndex tile, DiagDirection bridge_direction, bool opposite_side, uint &position, uint &x, uint &y)
 {
 	bool side = (_settings_game.vehicle.road_side != 0) && _settings_game.construction.train_signal_side;
+	side ^= opposite_side;
 
 	static const Point SignalPositions[2][4] = {
 		{   /*  X         X         Y         Y     Signals on the left side */
@@ -1863,9 +1867,10 @@ static void DrawBridgeSignalOnMiddlePart(const TileInfo *ti, TileIndex bridge_st
 	while (bridge_signal_position <= bridge_section) {
 		bridge_signal_position += simulated_wormhole_signals;
 		if (bridge_signal_position == bridge_section) {
+			uint8 style = GetBridgeSignalStyle(bridge_start_tile);
 
 			uint position, x, y;
-			GetBridgeSignalXY(ti->tile, GetTunnelBridgeDirection(bridge_start_tile), position, x, y);
+			GetBridgeSignalXY(ti->tile, GetTunnelBridgeDirection(bridge_start_tile), HasBit(_signal_opposite_side_style_mask, style), position, x, y);
 
 			SignalVariant variant = IsTunnelBridgeSemaphore(bridge_start_tile) ? SIG_SEMAPHORE : SIG_ELECTRIC;
 			SignalState state = GetBridgeEntranceSimulatedSignalState(bridge_start_tile, m2_position);
@@ -1889,7 +1894,7 @@ static void DrawBridgeSignalOnMiddlePart(const TileInfo *ti, TileIndex bridge_st
 			}
 
 			const RailtypeInfo *rti = GetRailTypeInfo(GetRailType(bridge_start_tile));
-			PalSpriteID sprite = GetCustomSignalSprite(rti, bridge_start_tile, SIGTYPE_NORMAL, variant, aspect, CSSC_BRIDGE_MIDDLE, GetBridgeSignalStyle(bridge_start_tile)).sprite;
+			PalSpriteID sprite = GetCustomSignalSprite(rti, bridge_start_tile, SIGTYPE_NORMAL, variant, aspect, CSSC_BRIDGE_MIDDLE, style).sprite;
 
 			if (sprite.sprite != 0) {
 				sprite.sprite += position;
@@ -1920,8 +1925,13 @@ void MarkSingleBridgeSignalDirty(TileIndex tile, TileIndex bridge_start_tile)
 		return;
 	}
 
+	bool opposite_side = false;
+	if (_signal_opposite_side_style_mask != 0) {
+		opposite_side = HasBit(_signal_opposite_side_style_mask, GetTunnelBridgeSignalStyle(bridge_start_tile));
+	}
+
 	uint position, x, y;
-	GetBridgeSignalXY(tile, GetTunnelBridgeDirection(bridge_start_tile), position, x, y);
+	GetBridgeSignalXY(tile, GetTunnelBridgeDirection(bridge_start_tile), opposite_side, position, x, y);
 	Point pt = RemapCoords(x, y, GetBridgePixelHeight(bridge_start_tile) + 5 - BRIDGE_Z_START);
 	MarkAllViewportsDirty(
 			pt.x - SIGNAL_DIRTY_LEFT,
@@ -1939,15 +1949,22 @@ void MarkTunnelBridgeSignalDirty(TileIndex tile, bool exit)
 		return;
 	}
 
+	bool opposite_side = false;
+	if (_signal_opposite_side_style_mask != 0) {
+		opposite_side = HasBit(_signal_opposite_side_style_mask, GetTunnelBridgeSignalStyle(tile));
+	}
+
 	if (IsRailCustomBridgeHeadTile(tile)) {
 		Trackdir td = exit ? GetTunnelBridgeExitTrackdir(tile) : GetTunnelBridgeEntranceTrackdir(tile);
-		MarkSingleSignalDirtyAtZ(tile, td, GetTileMaxPixelZ(tile));
+		MarkSingleSignalDirtyAtZ(tile, td, opposite_side, GetTileMaxPixelZ(tile));
 		return;
 	}
 
 	bool side = (_settings_game.vehicle.road_side != 0) && _settings_game.construction.train_signal_side;
 	DiagDirection dir = GetTunnelBridgeDirection(tile);
 
+	side ^= opposite_side;
+
 	uint position;
 	switch (dir) {
 		default: NOT_REACHED();