public static VCircleEvent CircleCheckDataNode(VDataNode n, double ys)
{
VDataNode l = VNode.LeftDataNode(n);
VDataNode r = VNode.RightDataNode(n);
if(l==null || r==null || l.DataPoint==r.DataPoint || l.DataPoint==n.DataPoint || n.DataPoint==r.DataPoint)
return null;
if(MathTools.ccw(l.DataPoint[0],l.DataPoint[1],n.DataPoint[0],n.DataPoint[1],r.DataPoint[0],r.DataPoint[1],false)<=0)
return null;
Vector Center = Fortune.CircumCircleCenter(l.DataPoint,n.DataPoint,r.DataPoint);
VCircleEvent VC = new VCircleEvent();
VC.NodeN = n;
VC.NodeL = l;
VC.NodeR = r;
VC.Center = Center;
VC.Valid = true;
if(VC.Y>ys || Math.Abs(VC.Y - ys) < 1e-10)
return VC;
return null;
}
