public void SortByAngle(ref List <Vector3> points)
{
//Find Angle based on initial point and Z Axis
var startPoint = points[0];
AngleComparer comparer = new AngleComparer(startPoint);
var zAxis = -Vector3.forward;
points.Sort(1, points.Count - 1, comparer);
}
/// <summary>
/// Bestimmt die convexe Hülle dieses Polygons.
/// </summary>
public static IPolygon ConvexHull(this IPolygon value)
{
var startPoint = value.GetPoints().OrderBy(item => item.Y).ThenBy(item => item.X).First();
var comp = new AngleComparer(startPoint);
var sorted = value.GetPoints().OrderBy(item => item, comp).ToArray();
var result = new Stack <Point2D>();
result.Push(sorted[0]);
result.Push(sorted[1]);
for (int i = 2; i < sorted.Length; i++)
{
while (GetSweepDirection(result.ElementAt(1), result.ElementAt(0), sorted[i]) > 0)
{
result.Pop();
}
result.Push(sorted[i]);
}
return(new CustomPolygon(result.ToArray()));
}
public static List <Tuple <int, int> > ConvexHull(IEnumerable <Tuple <int, int> > input)
{
if (input == null)
{
throw new ArgumentNullException("input");
}
List <Tuple <int, int> > points = new List <Tuple <int, int> >(input);
Tuple <int, int> start = new Tuple <int, int>(int.MaxValue, int.MaxValue);
List <int> indexes = new List <int>();
for (int i = 0; i < points.Count; i++)
{
if (points[i].Item2 < start.Item2 || points[i].Item2 == start.Item2 && points[i].Item1 < start.Item1)
{
start = points[i];
indexes.Clear();
indexes.Add(i);
}
else if (points[i] == start)
{
indexes.Add(i);
}
}
for (int i = 0; i < indexes.Count; i++)
{
points.RemoveAt(indexes[i] - i);
}
AngleComparer comp = new AngleComparer(start);
points.Sort(comp);
List <Tuple <int, int> > temp = new List <Tuple <int, int> >();
for (int i = 0; i < points.Count; i++)
{
while (i < points.Count - 1 && comp.Compare(points[i], points[i + 1]) == 0)
{
if (Distance(points[i], start) - Distance(points[i + 1], start) <= 0)
{
i++;
}
else
{
Tuple <int, int> t = points[i];
points[i] = points[i + 1];
points[i + 1] = t;
i++;
}
}
temp.Add(points[i]);
}
points = temp;
if (points.Count < 2)
{
return(null);
}
Stack <Tuple <int, int> > hull = new Stack <Tuple <int, int> >();
hull.Push(start);
hull.Push(points[0]);
hull.Push(points[1]);
Tuple <int, int> top, belowTop;
for (int i = 2; i < points.Count; i++)
{
top = hull.Pop();
belowTop = hull.Pop();
while (!LeftTurn(belowTop, top, points[i]))
{
top = belowTop;
belowTop = hull.Pop();
}
hull.Push(belowTop);
hull.Push(top);
hull.Push(points[i]);
}
points.Clear();
while (hull.Count > 0)
{
points.Add(hull.Pop());
}
return(points);
}
/// <summary>
/// Returns the smallest polygon that contains all the points in the input.
/// </summary>
/// <param name="input">The set of points to calculate the convex hull of.</param>
/// <returns>A list of points describing the convex hull in clockwise order.</returns>
public static List <Vector2D> ConvexHull(IEnumerable <Vector2D> input)
{
if (input == null)
{
throw new ArgumentNullException("input");
}
List <Vector2D> points = new List <Vector2D>(input);
Vector2D start = new Vector2D(double.MaxValue, double.MaxValue);
List <int> indexes = new List <int>();
for (int i = 0; i < points.Count; i++)
{
if (points[i].Y < start.Y || points[i].Y == start.Y && points[i].X < start.X)
{
start = points[i];
indexes.Clear();
indexes.Add(i);
}
else if (points[i] == start)
{
indexes.Add(i);
}
}
for (int i = 0; i < indexes.Count; i++)
{
points.RemoveAt(indexes[i] - i);
}
AngleComparer comp = new AngleComparer(start);
points.Sort(comp);
List <Vector2D> temp = new List <Vector2D>();
for (int i = 0; i < points.Count; i++)
{
while (i < points.Count - 1 && comp.Compare(points[i], points[i + 1]) == 0)
{
if (Vector2D.Distance(points[i], start) - Vector2D.Distance(points[i + 1], start) <= 0)
{
i++;
}
else
{
Vector2D t = points[i];
points[i] = points[i + 1];
points[i + 1] = t;
i++;
}
}
temp.Add(points[i]);
}
points = temp;
if (points.Count < 2)
{
return(null);
}
Stack <Vector2D> hull = new Stack <Vector2D>();
hull.Push(start);
hull.Push(points[0]);
hull.Push(points[1]);
Vector2D top, belowTop;
for (int i = 2; i < points.Count; i++)
{
top = hull.Pop();
belowTop = hull.Pop();
while (!LeftTurn(belowTop, top, points[i]))
{
top = belowTop;
belowTop = hull.Pop();
}
hull.Push(belowTop);
hull.Push(top);
hull.Push(points[i]);
}
points.Clear();
while (hull.Count > 0)
{
points.Add(hull.Pop());
}
return(points);
}
