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;}
 

grid/walk/v2/GridWalker.h

@@ -91,7 +91,7 @@ public:
 		}
 
 		//if (cnt != 0) {probability /= cnt;} else {probability = 1.0;}
-		probability = curNode->getWalkImportance() < 0.4f ? (1e-5) : (1.0);		// "kill" particles that walk near walls (most probably trapped ones)
+		probability *= curNode->getWalkImportance() < 0.4f ? (1e-5) : (1.0);		// "kill" particles that walk near walls (most probably trapped ones)
 
 		// update after
 		updateAfter(currentState, *startNode, *curNode);