(svn r21936) -Fix [FS#4457](r19231): Do not remove existing road/tram bits when overbuilding stops of the opposite road type.

-Change: Build only the required road/tram bits when building stops with drag and drop.

1 files changed, 6 insertions, 5 deletions

diff --git a/src/station_cmd.cpp b/src/station_cmd.cpp
index 04694543b..9aae855cb 100644
--- a/src/station_cmd.cpp
+++ b/src/station_cmd.cpp
@@ -827,10 +827,10 @@ static CommandCost CheckFlatLandRailStation(TileArea tile_area, DoCommandFlag fl
  * @param is_truck_stop True when building a truck stop, false otherwise.
  * @param axis Axis of a drive-through road stop.
  * @param station StationID to be queried and returned if available.
- * @param rts Road types to build. Bits already built at the tile will be removed.
+ * @param rts Road types to build.
  * @return The cost in case of success, or an error code if it failed.
  */
-static CommandCost CheckFlatLandRoadStop(TileArea tile_area, DoCommandFlag flags, uint invalid_dirs, bool is_drive_through, bool is_truck_stop, Axis axis, StationID *station, RoadTypes &rts)
+static CommandCost CheckFlatLandRoadStop(TileArea tile_area, DoCommandFlag flags, uint invalid_dirs, bool is_drive_through, bool is_truck_stop, Axis axis, StationID *station, RoadTypes rts)
 {
 	CommandCost cost(EXPENSES_CONSTRUCTION);
 	int allowed_z = -1;
@@ -906,7 +906,7 @@ static CommandCost CheckFlatLandRoadStop(TileArea tile_area, DoCommandFlag flags
 					num_roadbits += CountBits(GetRoadBits(cur_tile, ROADTYPE_TRAM));
 				}
 
-				/* Do not remove roadtypes! */
+				/* Take into account existing roadbits. */
 				rts |= cur_rts;
 			} else {
 				ret = DoCommand(cur_tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
@@ -1787,6 +1787,8 @@ CommandCost CmdBuildRoadStop(TileIndex tile, DoCommandFlag flags, uint32 p1, uin
 	if (flags & DC_EXEC) {
 		/* Check every tile in the area. */
 		TILE_AREA_LOOP(cur_tile, roadstop_area) {
+			RoadTypes cur_rts = GetRoadTypes(cur_tile);
+
 			if (IsTileType(cur_tile, MP_STATION) && IsRoadStop(cur_tile)) {
 				RemoveRoadStop(cur_tile, flags);
 			}
@@ -1809,10 +1811,9 @@ CommandCost CmdBuildRoadStop(TileIndex tile, DoCommandFlag flags, uint32 p1, uin
 
 			RoadStopType rs_type = type ? ROADSTOP_TRUCK : ROADSTOP_BUS;
 			if (is_drive_through) {
-				RoadTypes cur_rts = IsNormalRoadTile(cur_tile) ? GetRoadTypes(cur_tile) : ROADTYPES_NONE;
 				Owner road_owner = HasBit(cur_rts, ROADTYPE_ROAD) ? GetRoadOwner(cur_tile, ROADTYPE_ROAD) : _current_company;
 				Owner tram_owner = HasBit(cur_rts, ROADTYPE_TRAM) ? GetRoadOwner(cur_tile, ROADTYPE_TRAM) : _current_company;
-				MakeDriveThroughRoadStop(cur_tile, st->owner, road_owner, tram_owner, st->index, rs_type, rts, DiagDirToAxis(ddir));
+				MakeDriveThroughRoadStop(cur_tile, st->owner, road_owner, tram_owner, st->index, rs_type, rts | cur_rts, DiagDirToAxis(ddir));
 				road_stop->MakeDriveThrough();
 			} else {
 				MakeRoadStop(cur_tile, st->owner, st->index, rs_type, rts, ddir);