(svn r25221) -Fix: IsCompatibleTrainStationTile() is not a symmetric function. Clarify the parameters and fix the cases were they were swapped.

src/newgrf_station.cpp

@@ -73,8 +73,8 @@ struct ETileArea : TileArea {
 				Axis axis = GetRailStationAxis(tile);
 				TileIndexDiff delta = TileOffsByDiagDir(AxisToDiagDir(axis));
 
-				for (end = tile; IsRailStationTile(end + delta) && IsCompatibleTrainStationTile(tile, end + delta); end += delta) { /* Nothing */ }
-				for (start = tile; IsRailStationTile(start - delta) && IsCompatibleTrainStationTile(tile, start - delta); start -= delta) { /* Nothing */ }
+				for (end = tile; IsRailStationTile(end + delta) && IsCompatibleTrainStationTile(end + delta, tile); end += delta) { /* Nothing */ }
+				for (start = tile; IsRailStationTile(start - delta) && IsCompatibleTrainStationTile(start - delta, tile); start -= delta) { /* Nothing */ }
 
 				this->tile = start;
 				this->w = TileX(end) - TileX(start) + 1;

src/station_map.h

@@ -364,25 +364,25 @@ static inline TrackBits GetRailStationTrackBits(TileIndex t)
 }
 
 /**
- * Check if tile is compatible with a railstation tile. The two tiles
- * are compatible if all of the following are true:
- * \li both tiles are rail station tiles
- * \li the railtype of \a t1 is compatible with the railtype of \a t2
- * \li the tracks on \a t1 and \a t2 are in the same direction
+ * Check if a tile is a valid continuation to a railstation tile.
+ * The tile \a test_tile is a valid continuation to \a station_tile, if all of the following are true:
+ * \li \a test_tile is a rail station tile
+ * \li the railtype of \a test_tile is compatible with the railtype of \a station_tile
+ * \li the tracks on \a test_tile and \a station_tile are in the same direction
  * \li both tiles belong to the same station
- * \li \a t1 is not blocked (@see IsStationTileBlocked)
- * @param t1 First tile to compare
- * @param t2 Second tile to compare
- * @pre IsRailStationTile(t2)
+ * \li \a test_tile is not blocked (@see IsStationTileBlocked)
+ * @param test_tile Tile to test
+ * @param station_tile Station tile to compare with
+ * @pre IsRailStationTile(station_tile)
  * @return true if the two tiles are compatible
  */
-static inline bool IsCompatibleTrainStationTile(TileIndex t1, TileIndex t2)
+static inline bool IsCompatibleTrainStationTile(TileIndex test_tile, TileIndex station_tile)
 {
-	assert(IsRailStationTile(t2));
-	return IsRailStationTile(t1) && IsCompatibleRail(GetRailType(t1), GetRailType(t2)) &&
-			GetRailStationAxis(t1) == GetRailStationAxis(t2) &&
-			GetStationIndex(t1) == GetStationIndex(t2) &&
-			!IsStationTileBlocked(t1);
+	assert(IsRailStationTile(station_tile));
+	return IsRailStationTile(test_tile) && IsCompatibleRail(GetRailType(test_tile), GetRailType(station_tile)) &&
+			GetRailStationAxis(test_tile) == GetRailStationAxis(station_tile) &&
+			GetStationIndex(test_tile) == GetStationIndex(station_tile) &&
+			!IsStationTileBlocked(test_tile);
 }
 
 /**