+ void invalidatePositionedCache()
+ {
+ _cachedItemsValid = false;
+ }
+
+ double textureSize() const
+ { return _textureSize; }
+
+ void forceUpdate()
+ { _forceUpdate = true; }
+
+ bool anyRuleForType(const std::string& type) const;
+ bool isPositionedShown(FGPositioned* pos);