private void AddSite (Vector2 p, uint color, int index)
{
if (_sitesIndexedByLocation.ContainsKey (p))
return; // Prevent duplicate site! (Adapted from https://github.com/nodename/as3delaunay/issues/1)
float weight = UnityEngine.Random.value * 100f;
Site site = Site.Create (p, (uint)index, weight, color);
_sites.Add (site);
_sitesIndexedByLocation [p] = site;
}