function locallyInside(a, b) {
	    return area(a.prev, a, a.next) < 0 ?
	        area(a, b, a.next) >= 0 && area(a, a.prev, b) >= 0 :
	        area(a, b, a.prev) < 0 || area(a, a.next, b) < 0;
	}
// check if a polygon diagonal is locally inside the polygon
check if a polygon diagonal is locally inside the polygon
check if a polygon diagonal is locally inside the polygon
function locallyInside(a, b) {
	    return area(a.prev, a, a.next) < 0 ?
	        area(a, b, a.next) >= 0 && area(a, a.prev, b) >= 0 :
	        area(a, b, a.prev) < 0 || area(a, a.next, b) < 0;
	}
function locallyInside ( a , b ) { return area ( a . prev , a , a . next ) < 0 ? area ( a , b , a . next ) >= 0 && area ( a , a . prev , b ) >= 0 : area ( a , b , a . prev ) < 0 || area ( a , a . next , b ) < 0 ; }
check if a polygon diagonal is locally inside the polygon
check if a polygon diagonal is locally inside the polygon