private Point[] DoRecurse(Point[] ps)
{
if (ps.Length < FLOOR)
{
return(HullTools.GetConvexHull(ps).ToArray());
}
var hull = new Hull(ps);
var twoSets = HullTools.Split(hull);
var first = DoRecurse(twoSets.Item1.Points);
var second = DoRecurse(twoSets.Item2.Points);
return(CreatUnion(new Hull(first), new Hull(second)));
}
private Point[] CreatUnion(Hull first, Hull second)
{
var aPoint = HullTools.GetInnerPoint(first);
Point[] merged;
if (HullTools.IsWithinPolygon(aPoint, second))
{
merged = HullTools.MergePointsByPolarAngle(first.Points, second.Points);
}
else
{
var twoLines = HullTools.GetSupportPoints(aPoint, second);
var tempHull = new Hull(new[] { twoLines.Item1, twoLines.Item2, aPoint });
merged = HullTools.MergePointsByPolarAngle(
first.Points.Where(x => !HullTools.IsWithinPolygon(x, tempHull)).ToArray(),
second.Points.Where(x => !HullTools.IsWithinPolygon(x, tempHull)).ToArray()
);
}
return(HullTools.GetConvexHull(merged).ToArray());
}
