new helper methods

particle traps

geo/BBox2.h

@@ -36,6 +36,11 @@ public:
 
 	}
 
+	/** returns true if the bbox is not yet configured */
+	const bool isInvalid() const {
+		return p1.x == MAX || p1.y == MAX || p2.x == MIN || p2.y == MIN;
+	}
+
 	/** get the bbox's minimum */
 	const Point2& getMin() const {return p1;}