GRF: Add road stops variable for road info of nearby plain road tile

See: #464

docs/newgrf-roadstops-nml.html

@@ -165,6 +165,12 @@
 		<tr><td>nearby_tile_one_way_info</td><td>x, y offset (-8..7)</td><td>RST_OWI_XXX</td><td>One-way state of nearby drive-through road stop tile</td></tr>
 		<tr><td>nearby_tile_road_stop_info</td><td>x, y offset (-8..7)</td><td></td><td>Above nearby road stop tile variables in one variable (all of variable 0x68)</td></tr>
 		<tr><td>nearby_tile_grfid</td><td>x, y offset (-8..7)</td><td>-1, 0 or a GRFID</td><td>Return value is -1 if the tile is not a road stop, 0 if the tile is a non-custom road stop, or else the GRFID of the NewGRF defining the road stop</td></tr>
+		<tr><td>nearby_tile_is_plain_road</td><td>x, y offset (-8..7)</td><td>0 | 1</td><td>Is nearby tile a plain road tile</td></tr>
+		<tr><td>nearby_tile_road_bits</td><td>x, y offset (-8..7)</td><td>bitmask(ROADBIT_XXX, ...)</td><td>XXX = [NW | SW | SE | NE]<br />Present road bits on nearby tile</td></tr>
+		<tr><td>nearby_tile_tram_bits</td><td>x, y offset (-8..7)</td><td>bitmask(ROADBIT_XXX, ...)</td><td>XXX = [NW | SW | SE | NE]<br />Present tram bits on nearby tile</td></tr>
+		<tr><td>nearby_tile_road_piece</td><td>x, y offset (-8..7)</td><td>0..18 | 0xFF</td><td>Present road piece and slope in <a href="https://newgrf-specs.tt-wiki.net/wiki/Action3/Roadtypes#Road_underlay_.2802.29">sprite order</a>, or 0xFF if none</td></tr>
+		<tr><td>nearby_tile_tram_piece</td><td>x, y offset (-8..7)</td><td>0..18 | 0xFF</td><td>Present tram piece and slope in <a href="https://newgrf-specs.tt-wiki.net/wiki/Action3/Roadtypes#Road_underlay_.2802.29">sprite order</a>, or 0xFF if none</td></tr>
+		<tr><td>nearby_tile_road_stop_info</td><td>x, y offset (-8..7)</td><td></td><td>Above nearby road tile variables in one variable (all of variable 0x6B)</td></tr>
 	</table>
 
 	<h3 id="roadstop_callbacks">Road Stop Callbacks</h3>

docs/newgrf-roadstops.html

@@ -228,6 +228,7 @@
 		<tr><td><a href="#roadstop_road_stop_info_nearby_tiles">68</a></td><td><a href="#roadstop_road_stop_info_nearby_tiles">roadstop_road_stop_info_nearby_tiles</a></td><td>Road stop info of nearby tiles</td></tr>
 		<tr><td><a href="https://newgrf-specs.tt-wiki.net/wiki/VariationalAction2/BaseStation">69</a></td><td></td><td>Information about cargo accepted in the past (BaseStation)</td></tr>
 		<tr><td><a href="#roadstop_road_stop_grfid_nearby_tiles">6A</a></td><td><a href="#roadstop_road_stop_grfid_nearby_tiles">roadstop_road_stop_grfid_nearby_tiles</a></td><td>GRFID of nearby road stop tiles</td></tr>
+		<tr><td><a href="#roadstop_road_info_nearby_tiles">6B</a></td><td><a href="#roadstop_road_info_nearby_tiles">roadstop_road_info_nearby_tiles</a></td><td>Road info of nearby plain road tiles</td></tr>
 	</table>
 
 	<h4 id="roadstop_view">Road stop view/rotation (40, or mappable variable: roadstop_view)</h4>
@@ -342,6 +343,39 @@
 	<h4 id="roadstop_road_stop_grfid_nearby_tiles">GRFID of nearby road stop tile (6A, or mappable variable: roadstop_road_stop_grfid_nearby_tiles)</h4>
 	<p>This has the same value as <a href="https://newgrf-specs.tt-wiki.net/wiki/VariationalAction2/Stations#GRFID_of_nearby_station_tile_.286A.29">station (feature 4) variable 6A</a>.</p>
 
+	<h4 id="roadstop_road_info_nearby_tiles">Road info of nearby plain road tiles (6B, or mappable variable: roadstop_road_info_nearby_tiles)</h4>
+
+	The returned value is 0xFFFFFFFF if the selected tile isn't a plain road tile.<br /><br />
+
+	<table>
+	<tr><th>Bits</th><th>Value</th><th>Meaning</th></tr>
+	<tr><td>0</td><td>01</td><td>North-west road piece is present</td></tr>
+	<tr><td>1</td><td>02</td><td>South-west road piece is present</td></tr>
+	<tr><td>2</td><td>04</td><td>South-east road piece is present</td></tr>
+	<tr><td>3</td><td>08</td><td>North-east road piece is present</td></tr>
+	<tr><td>4</td><td>10</td><td>North-west tram piece is present</td></tr>
+	<tr><td>5</td><td>20</td><td>South-west tram piece is present</td></tr>
+	<tr><td>6</td><td>40</td><td>South-east tram piece is present</td></tr>
+	<tr><td>7</td><td>80</td><td>North-east tram piece is present</td></tr>
+	<tr><td>8 - 15</td><td></td><td>
+		Road piece and slope:<br />
+		(Same order as <a href="https://newgrf-specs.tt-wiki.net/wiki/Action3/Roadtypes#Road_underlay_.2802.29">road sprites</a>).<br />
+		0 - 18: As above<br />
+		0xFF: No road present
+	</td></tr>
+	<tr><td>16 - 23</td><td></td><td>
+		Tram piece and slope:<br />
+		(Same order as <a href="https://newgrf-specs.tt-wiki.net/wiki/Action3/Roadtypes#Road_underlay_.2802.29">road sprites</a>).<br />
+		0 - 18: As above<br />
+		0xFF: No tram present
+	</td></tr>
+	</table>
+	<br />
+	The remaining bits are reserved for future use and should be masked.
+	<br />
+	This requires <font face="monospace">road_stops</font>, version 5.
+	</p>
+
 	<br />
 	<h3 id="randomaction2roadstops">Random Action 2 - Road Stops</h3>
 

src/newgrf_extension.cpp

@@ -55,7 +55,7 @@ extern const GRFFeatureInfo _grf_feature_list[] = {
 	GRFFeatureInfo("action0_object_edge_foundation_mode", 2),
 	GRFFeatureInfo("action0_object_flood_resistant", 1),
 	GRFFeatureInfo("action0_object_viewport_map_tile_type", 1),
-	GRFFeatureInfo("road_stops", 4),
+	GRFFeatureInfo("road_stops", 5),
 	GRFFeatureInfo("new_landscape", 2),
 	GRFFeatureInfo(),
 };
@@ -147,6 +147,7 @@ extern const GRFVariableMapDefinition _grf_action2_remappable_variables[] = {
 	GRFVariableMapDefinition(GSF_ROADSTOPS, 0x67, "roadstop_land_info_nearby_tiles"),
 	GRFVariableMapDefinition(GSF_ROADSTOPS, 0x68, "roadstop_road_stop_info_nearby_tiles"),
 	GRFVariableMapDefinition(GSF_ROADSTOPS, 0x6A, "roadstop_road_stop_grfid_nearby_tiles"),
+	GRFVariableMapDefinition(GSF_ROADSTOPS, 0x6B, "roadstop_road_info_nearby_tiles"),
 	GRFVariableMapDefinition(GSF_RAILTYPES, A2VRI_RAILTYPE_SIGNAL_RESTRICTION_INFO, "railtype_signal_restriction_info"),
 	GRFVariableMapDefinition(GSF_RAILTYPES, A2VRI_RAILTYPE_SIGNAL_CONTEXT, "railtype_signal_context"),
 	GRFVariableMapDefinition(GSF_SIGNALS, A2VRI_SIGNALS_SIGNAL_RESTRICTION_INFO, "signals_signal_restriction_info"),

src/newgrf_roadstop.cpp

@@ -187,6 +187,23 @@ uint32 RoadStopScopeResolver::GetVariable(uint16 variable, uint32 parameter, Get
 			return ssl.grfid;
 		}
 
+		/* Road info of nearby tiles */
+		case 0x6B: {
+			if (this->tile == INVALID_TILE) return 0xFFFFFFFF;
+			TileIndex nearby_tile = GetNearbyTile(parameter, this->tile);
+
+			if (!IsNormalRoadTile(nearby_tile)) return 0xFFFFFFFF;
+
+			RoadBits road = GetRoadBits(nearby_tile, RTT_ROAD);
+			RoadBits tram = GetRoadBits(nearby_tile, RTT_TRAM);
+			Slope tileh = GetTileSlope(nearby_tile);
+			extern uint GetRoadSpriteOffset(Slope slope, RoadBits bits);
+			uint road_offset = (road == 0) ? 0xFF : GetRoadSpriteOffset(tileh, road);
+			uint tram_offset = (tram == 0) ? 0xFF : GetRoadSpriteOffset(tileh, tram);
+
+			return (tram_offset << 16) | (road_offset << 8) | (tram << 4) | (road);
+		}
+
 		case 0xF0: return this->st == nullptr ? 0 : this->st->facilities; // facilities
 
 		case 0xFA: return Clamp((this->st == nullptr ? _date : this->st->build_date) - DAYS_TILL_ORIGINAL_BASE_YEAR, 0, 65535); // build date

src/road_cmd.cpp

@@ -1866,7 +1866,7 @@ const byte _road_sloped_sprites[14] = {
  * @param bits Roadbits
  * @return Offset for the sprite within the spritegroup.
  */
-static uint GetRoadSpriteOffset(Slope slope, RoadBits bits)
+uint GetRoadSpriteOffset(Slope slope, RoadBits bits)
 {
 	if (slope != SLOPE_FLAT) {
 		switch (slope) {

src/table/newgrf_debug_data.h

@@ -1701,6 +1701,7 @@ static const NIVariable _nif_roadstops[] = {
 	NIV(0x68, "road stop info of nearby tiles"),
 	NIV(0x69, "information about cargo accepted in the past"),
 	NIV(0x6A, "GRFID of nearby road stop tiles"),
+	NIV(0x6B, "Road info of nearby plain road tiles"),
 	NIV_END(),
 };