Add signal style flag to limit lookahead extra aspect

docs/newgrf-additions-nml.html

@@ -471,6 +471,15 @@ item (FEAT_GLOBALVARS) {
 			Set whether reserve through is unconditionally enabled for the most recently defined style (defined using the define_style property).
 		</td>
 	</tr>
+	<tr><td>style_lookahead_extra_aspects</td><td>0 - 6</td>
+		<td>
+			Set the look-ahead extra aspects for the most recently defined style (defined using the define_style property).<br />
+			This property only makes a difference when the "limit train lookahead to signal aspect" game setting is enabled.<br />
+			This limits the signal aspect which the hypothetical train driver can "read" from the signal without affecting signal aspect propagation to other signals, or variable <span class="code">extra_callback_info2</span>.<br />
+			Example values could include: 1 for traditional banner repeater signals, or 0 for shunt signals.<br />
+			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>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

@@ -445,6 +445,15 @@
 	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_lookahead_extra_aspects">Set custom signal style train look-ahead extra aspects (mappable property: signals_style_lookahead_extra_aspects)</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 limits the signal aspect which the hypothetical train driver can "read" from the signal without affecting signal aspect propagation to other signals, or variable 0x18.<br />
+	Example values could include: 1 for traditional banner repeater signals, or 0 for shunt signals.</p>
+	<p>The property length is 1 byte. The value is clamped to be less than or equal to the value set in the <a href="#signals_extra_aspects">signals_extra_aspects</a> property.<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

@@ -4243,6 +4243,16 @@ static ChangeInfoResult SignalsChangeInfo(uint id, int numinfo, int prop, const
 				break;
 			}
 
+			case A0RPI_SIGNALS_STYLE_LOOKAHEAD_EXTRA_ASPECTS: {
+				if (MappedPropertyLengthMismatch(buf, 1, mapping_entry)) break;
+				uint8 value = std::min<byte>(buf->ReadByte(), NEW_SIGNALS_MAX_EXTRA_ASPECT);
+				if (_cur.grffile->current_new_signal_style != nullptr) {
+					SetBit(_cur.grffile->current_new_signal_style->style_flags, NSSF_LOOKAHEAD_ASPECTS_SET);
+					_cur.grffile->current_new_signal_style->lookahead_extra_aspects = value;
+				}
+				break;
+			}
+
 			default:
 				ret = HandleAction0PropertyDefault(buf, prop);
 				break;

src/newgrf_extension.cpp

@@ -96,6 +96,7 @@ extern const GRFPropertyMapDefinition _grf_action0_remappable_properties[] = {
 	GRFPropertyMapDefinition(GSF_SIGNALS, A0RPI_SIGNALS_STYLE_NAME, "signals_style_name"),
 	GRFPropertyMapDefinition(GSF_SIGNALS, A0RPI_SIGNALS_STYLE_NO_ASPECT_INCREASE, "signals_style_no_aspect_increase"),
 	GRFPropertyMapDefinition(GSF_SIGNALS, A0RPI_SIGNALS_STYLE_ALWAYS_RESERVE_THROUGH, "signals_style_always_reserve_through"),
+	GRFPropertyMapDefinition(GSF_SIGNALS, A0RPI_SIGNALS_STYLE_LOOKAHEAD_EXTRA_ASPECTS, "signals_style_lookahead_extra_aspects"),
 	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

@@ -40,6 +40,7 @@ enum Action0RemapPropertyIds {
 	A0RPI_SIGNALS_STYLE_NAME,
 	A0RPI_SIGNALS_STYLE_NO_ASPECT_INCREASE,
 	A0RPI_SIGNALS_STYLE_ALWAYS_RESERVE_THROUGH,
+	A0RPI_SIGNALS_STYLE_LOOKAHEAD_EXTRA_ASPECTS,
 	A0RPI_OBJECT_USE_LAND_GROUND,
 	A0RPI_OBJECT_EDGE_FOUNDATION_MODE,
 	A0RPI_OBJECT_FLOOD_RESISTANT,

src/newgrf_newsignals.h

@@ -27,6 +27,7 @@ enum {
 enum NewSignalStyleFlags {
 	NSSF_NO_ASPECT_INC                  = 0,
 	NSSF_ALWAYS_RESERVE_THROUGH         = 1,
+	NSSF_LOOKAHEAD_ASPECTS_SET          = 2,
 };
 
 struct NewSignalStyle {
@@ -34,6 +35,7 @@ struct NewSignalStyle {
 	StringID name;
 	uint8 grf_local_id;
 	uint8 style_flags;
+	uint8 lookahead_extra_aspects;
 
 	PalSpriteID signals[SIGTYPE_END][2][2];
 };

src/pbs.cpp

@@ -13,6 +13,7 @@
 #include "newgrf_station.h"
 #include "pathfinder/follow_track.hpp"
 #include "tracerestrict.h"
+#include "newgrf_newsignals.h"
 
 #include "safeguards.h"
 
@@ -584,8 +585,10 @@ static PBSTileInfo FollowReservation(Owner o, RailTypes rts, TileIndex tile, Tra
 					if (signal_speed == 0 || (speed_restriction != 0 && speed_restriction < signal_speed)) signal_speed = speed_restriction;
 					if (signal_speed == 0 || (bridge_speed != 0 && bridge_speed < signal_speed)) signal_speed = bridge_speed;
 
+					const uint16 signal_flags = GetTunnelBridgeSignalStyle(tile) << 8;
+
 					/* Entrance signal */
-					lookahead->AddSignal(signal_speed, 0, z, 0);
+					lookahead->AddSignal(signal_speed, 0, z, signal_flags);
 
 					update_z(tile, trackdir, false);
 
@@ -599,7 +602,7 @@ static PBSTileInfo FollowReservation(Owner o, RailTypes rts, TileIndex tile, Tra
 					int offset = start_offset - TILE_SIZE;
 					for (int i = 0; i < signals; i++) {
 						offset += TILE_SIZE * spacing;
-						lookahead->AddSignal(signal_speed, offset, chunnel ? LookaheadTileHeightForChunnel(length, i * spacing) : z, 0);
+						lookahead->AddSignal(signal_speed, offset, chunnel ? LookaheadTileHeightForChunnel(length, i * spacing) : z, signal_flags);
 					}
 
 					/* Exit signal */
@@ -613,7 +616,7 @@ static PBSTileInfo FollowReservation(Owner o, RailTypes rts, TileIndex tile, Tra
 						if (signal_speed == 0 || (bridge_speed != 0 && bridge_speed < signal_speed)) signal_speed = bridge_speed;
 					}
 
-					lookahead->AddSignal(signal_speed, end_offset, z, 0);
+					lookahead->AddSignal(signal_speed, end_offset, z, signal_flags);
 
 					lookahead->SetNextExtendPositionIfUnset();
 				} else {
@@ -656,8 +659,9 @@ static PBSTileInfo FollowReservation(Owner o, RailTypes rts, TileIndex tile, Tra
 					/* Passing through a signal from the front side */
 					uint16 signal_speed = GetRailTypeInfo(rt)->max_speed;
 					if (signal_speed == 0 || (speed_restriction != 0 && speed_restriction < signal_speed)) signal_speed = speed_restriction;
-					uint16 signal_flags = 0;
-					if (_non_aspect_inc_style_mask != 0 && HasBit(_non_aspect_inc_style_mask, GetSignalStyle(tile, TrackdirToTrack(trackdir)))) {
+					uint8 signal_style = GetSignalStyle(tile, TrackdirToTrack(trackdir));
+					uint16 signal_flags = signal_style << 8;
+					if (HasBit(_non_aspect_inc_style_mask, signal_style)) {
 						SetBit(signal_flags, TRSLAI_NO_ASPECT_INC);
 					}
 					lookahead->AddSignal(signal_speed, 0, z, signal_flags);
@@ -953,11 +957,13 @@ void TryCreateLookAheadForTrainInTunnelBridge(Train *t)
 
 			int z = IsBridge(t->tile) ? GetBridgeHeight(t->tile) : GetTilePixelZ(t->tile);
 
+			const uint16 signal_flags = GetTunnelBridgeSignalStyle(t->tile) << 8;
+
 			/* Middle signals */
 			int offset = -(int)TILE_SIZE;
 			for (int i = 0; i < signals; i++) {
 				offset += TILE_SIZE * spacing;
-				t->lookahead->AddSignal(signal_speed, offset, HasBit(t->lookahead->flags, TRLF_CHUNNEL) ? LookaheadTileHeightForChunnel(length, i * spacing) : z, 0);
+				t->lookahead->AddSignal(signal_speed, offset, HasBit(t->lookahead->flags, TRLF_CHUNNEL) ? LookaheadTileHeightForChunnel(length, i * spacing) : z, signal_flags);
 			}
 
 			/* Exit signal */
@@ -970,7 +976,7 @@ void TryCreateLookAheadForTrainInTunnelBridge(Train *t)
 				if (signal_speed == 0 || (bridge_speed != 0 && bridge_speed < signal_speed)) signal_speed = bridge_speed;
 			}
 
-			t->lookahead->AddSignal(signal_speed, end_offset, z, 0);
+			t->lookahead->AddSignal(signal_speed, end_offset, z, signal_flags);
 
 			t->lookahead->SetNextExtendPositionIfUnset();
 		}
@@ -996,7 +1002,9 @@ void SetTrainReservationLookaheadEnd(Train *v)
 		if (item.type == TRLIT_SIGNAL) {
 			if (item.start <= threshold) {
 				/* Signal is within visual range */
-				uint8 max_aspect = _extra_aspects + (HasBit(item.data_aux, TRSLAI_NO_ASPECT_INC) ? 1 : 2);
+				uint8 style = item.data_aux >> 8;
+				uint8 max_aspect = (style == 0) ? _extra_aspects : _new_signal_styles[style - 1].lookahead_extra_aspects;
+				max_aspect += (HasBit(item.data_aux, TRSLAI_NO_ASPECT_INC) ? 1 : 2);
 				if (max_aspect > known_signals_ahead) known_signals_ahead = max_aspect;
 			}
 			if (!HasBit(item.data_aux, TRSLAI_NO_ASPECT_INC)) {

src/signal.cpp

@@ -1531,6 +1531,14 @@ static bool DetermineExtraAspectsVariable()
 				SetBit(_always_reserve_through_style_mask, i + 1);
 				SetBit(_no_tunnel_bridge_style_mask, i + 1);
 			}
+			if (HasBit(_new_signal_styles[i].style_flags, NSSF_LOOKAHEAD_ASPECTS_SET)) {
+				_new_signal_styles[i].lookahead_extra_aspects = std::min<uint8>(_new_signal_styles[i].lookahead_extra_aspects, _new_signal_styles[i].grffile->new_signal_extra_aspects);
+			} else {
+				_new_signal_styles[i].lookahead_extra_aspects = _new_signal_styles[i].grffile->new_signal_extra_aspects;
+			}
+		}
+		for (uint i = _num_new_signal_styles; i < MAX_NEW_SIGNAL_STYLES; i++) {
+			_new_signal_styles[i].lookahead_extra_aspects = new_extra_aspects;
 		}
 	}
 

src/table/newgrf_debug_data.h

@@ -276,7 +276,7 @@ class NIHVehicle : public NIHelper {
 							if (item.data_id > 0) print_braking_speed(item.start, item.data_id, item.z_pos);
 							break;
 						case TRLIT_SIGNAL:
-							b += seprintf(b, lastof(buffer), "signal: target speed: %u, flags:", item.data_id);
+							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 (_settings_game.vehicle.realistic_braking_aspect_limited == TRBALM_ON && l.lookahead_end_position == item.start) {
 								b += seprintf(b, lastof(buffer), ", lookahead end");