Add road/tram type flag to disallow tunnels

docs/newgrf-additions-nml.html

@@ -175,6 +175,8 @@
 				<dd>Scripts (AI/GS) may not build this roadtype</dd>
 				<dt>NO_TOWN_MODIFY</dt>
 				<dd>Towns may not modify tiles of this roadtype in any way whatsoever</dd>
+				<dt>NO_TUNNELS</dt>
+				<dd>Disallow tunnels for this roadtype</dd>
 			</dl>
 		</td>
 	</tr>
@@ -202,6 +204,8 @@
 				<dd>Scripts (AI/GS) may not build this tramtype</dd>
 				<dt>NO_TOWN_MODIFY</dt>
 				<dd>Towns may not modify tiles of this tramtype in any way whatsoever</dd>
+				<dt>NO_TUNNELS</dt>
+				<dd>Disallow tunnels for this tramtype</dd>
 			</dl>
 		</td>
 	</tr>

docs/newgrf-additions.html

@@ -327,6 +327,8 @@
 	<tr><th>Bit</th><th>Value</th><th>Meaning</th></tr>
 	<tr><td>0</td><td>1</td><td>Scripts (AI/GS) may not build this road/tram type</td></tr>
 	<tr><td>1</td><td>2</td><td>Towns may not modify tiles of this road/tram type in any way whatsoever</td></tr>
+	<tr><td>2</td><td>4</td><td>Disallow tunnels for this road/tram type<br />
+			Support for this bit is indicated by the feature name: <font face="monospace">action0_roadtype_extra_flags</font>, version 2.</td></tr>
 	</table>
 	</p>
 	<p>This is indicated by the feature name: <font face="monospace">action0_roadtype_extra_flags</font>, version 1</p>

src/lang/extra/english.txt

@@ -2026,3 +2026,5 @@ STR_SHIFT_KEY_NAME                                              :{BLACK}Shift
 STR_CTRL_KEY_NAME                                               :{BLACK}Ctrl
 STR_MODIFIER_TOGGLE_SHIFT_TOOLTIP                               :{BLACK}Click to invert state of Shift key
 STR_MODIFIER_TOGGLE_CTRL_TOOLTIP                                :{BLACK}Click to invert state of Ctrl key
+
+STR_ERROR_TUNNEL_DISALLOWED_ROAD                                :{WHITE}Tunnels not allowed for this road type

src/newgrf_extension.cpp

@@ -38,7 +38,7 @@ extern const GRFFeatureInfo _grf_feature_list[] = {
 	GRFFeatureInfo("action0_railtype_disable_realistic_braking", 1),
 	GRFFeatureInfo("action0_railtype_recolour", 1),
 	GRFFeatureInfo("action0_railtype_extra_aspects", 1),
-	GRFFeatureInfo("action0_roadtype_extra_flags", 1),
+	GRFFeatureInfo("action0_roadtype_extra_flags", 2),
 	GRFFeatureInfo("action0_roadtype_collision_mode", 1),
 	GRFFeatureInfo("varaction2_railtype_signal_context", 1),
 	GRFFeatureInfo("action0_global_extra_station_names", 2),

src/road.h

@@ -55,10 +55,9 @@ DECLARE_ENUM_AS_BIT_SET(RoadTypeFlags)
 enum RoadTypeExtraFlags {
 	RXTF_NOT_AVAILABLE_AI_GS = 0,                                ///< Bit number for unavailable for AI/GS
 	RXTF_NO_TOWN_MODIFICATION,                                   ///< Bit number for no town modification
+	RXTF_NO_TUNNELS,                                             ///< Bit number for no tunnels
 
 	RXTFB_NONE = 0,                                              ///< All flags cleared.
-	RXTFB_NOT_AVAILABLE_AI_GS = 1 << RXTF_NOT_AVAILABLE_AI_GS,   ///< Value for unavailable for AI/GS
-	RXTFB_NO_TOWN_MODIFICATION = 1 << RXTF_NO_TOWN_MODIFICATION, ///< Value for no town modification
 };
 DECLARE_ENUM_AS_BIT_SET(RoadTypeExtraFlags)
 
@@ -325,6 +324,17 @@ static inline bool RoadNoLevelCrossing(RoadType roadtype)
 	return HasBit(GetRoadTypeInfo(roadtype)->flags, ROTF_NO_LEVEL_CROSSING);
 }
 
+/**
+ * Test if road disallows tunnels
+ * @param roadtype The roadtype we are testing
+ * @return True iff the roadtype disallows tunnels
+ */
+static inline bool RoadNoTunnels(RoadType roadtype)
+{
+	assert(roadtype < ROADTYPE_END);
+	return HasBit(GetRoadTypeInfo(roadtype)->extra_flags, RXTF_NO_TUNNELS);
+}
+
 RoadType GetRoadTypeByLabel(RoadTypeLabel label, bool allow_alternate_labels = true);
 
 void ResetRoadTypes();

src/road_cmd.cpp

@@ -1330,6 +1330,8 @@ CommandCost CmdBuildRoad(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32
 				/* Only allow building the outer roadbit, so building long roads stops at existing bridges */
 				if (MirrorRoadBits(DiagDirToRoadBits(GetTunnelBridgeDirection(tile))) != pieces) goto do_clear;
 				if (HasTileRoadType(tile, rtt)) return_cmd_error(STR_ERROR_ALREADY_BUILT);
+				if (RoadNoTunnels(rt)) return_cmd_error(STR_ERROR_TUNNEL_DISALLOWED_ROAD);
+
 				/* Don't allow adding roadtype to the bridge/tunnel when vehicles are already driving on it */
 				CommandCost ret = TunnelBridgeIsFree(tile, other_end);
 				if (ret.Failed()) return ret;
@@ -3054,6 +3056,10 @@ CommandCost CmdConvertRoad(TileIndex tile, DoCommandFlag flags, uint32 p1, uint3
 				break;
 			case MP_TUNNELBRIDGE:
 				if (GetTunnelBridgeTransportType(tile) != TRANSPORT_ROAD) continue;
+				if (IsTunnel(tile) && RoadNoTunnels(to_type)) {
+					error.MakeError(STR_ERROR_TUNNEL_DISALLOWED_ROAD);
+					continue;
+				}
 				break;
 			default: continue;
 		}

src/road_gui.cpp

@@ -443,6 +443,7 @@ struct BuildRoadToolbarWindow : Window {
 		}
 		this->GetWidget<NWidgetCore>(WID_ROT_CONVERT_ROAD)->widget_data = rti->gui_sprites.convert_road;
 		this->GetWidget<NWidgetCore>(WID_ROT_BUILD_TUNNEL)->widget_data = rti->gui_sprites.build_tunnel;
+		if (HasBit(rti->extra_flags, RXTF_NO_TUNNELS)) this->DisableWidget(WID_ROT_BUILD_TUNNEL);
 	}
 
 	/**

src/table/newgrf_debug_data.h

@@ -1791,9 +1791,10 @@ class NIHRoadType : public NIHelper {
 					HasBit(rti->flags, ROTF_HIDDEN) ? 'h' : '-',
 					HasBit(rti->flags, ROTF_TOWN_BUILD) ? 'T' : '-');
 			output.print(buffer);
-			seprintf(buffer, lastof(buffer), "    Extra Flags: %c%c",
+			seprintf(buffer, lastof(buffer), "    Extra Flags: %c%c%c",
 					HasBit(rti->extra_flags, RXTF_NOT_AVAILABLE_AI_GS) ? 's' : '-',
-					HasBit(rti->extra_flags, RXTF_NO_TOWN_MODIFICATION) ? 't' : '-');
+					HasBit(rti->extra_flags, RXTF_NO_TOWN_MODIFICATION) ? 't' : '-',
+					HasBit(rti->extra_flags, RXTF_NO_TUNNELS) ? 'T' : '-');
 			output.print(buffer);
 			seprintf(buffer, lastof(buffer), "    Collision mode: %u", rti->collision_mode);
 			output.print(buffer);

src/tunnelbridge_cmd.cpp

@@ -966,6 +966,7 @@ CommandCost CmdBuildTunnel(TileIndex start_tile, DoCommandFlag flags, uint32 p1,
 		case TRANSPORT_ROAD:
 			roadtype = Extract<RoadType, 0, 6>(p1);
 			if (!ValParamRoadType(roadtype)) return CMD_ERROR;
+			if (RoadNoTunnels(roadtype)) return_cmd_error(STR_ERROR_TUNNEL_DISALLOWED_ROAD);
 			break;
 
 		default: return CMD_ERROR;