/// <summary>
/// Computes a convex hull using the Gift Wrap method.
/// </summary>
/// <param name="points"></param>
/// <param name="allocator"></param>
/// <returns></returns>
public static void Giftwrap(NativeArray <Vector2> points, Allocator allocator, ref NativeArray <Vector2> convexHullOut)
{
if (!points.IsCreated)
{
throw new ArgumentException("Array has been disposed.", nameof(points));
}
// pointOnHull is initialized to the leftmost point
// which is guaranteed to be part of the convex hull
int pointOnHull = 0;
for (int i = 1; i < points.Length; ++i)
{
if (points[i].x < points[pointOnHull].x)
{
pointOnHull = i;
}
}
using (var hullIndices = new NativeFixedList <int>(points.Length, Allocator.Temp))
{
int endpoint = 0;
do
{
hullIndices.Add(pointOnHull);
endpoint = 0; // initial endpoint for a candidate edge on the hull
for (int j = 1; j < points.Length; ++j)
{
endpoint = (endpoint == pointOnHull || IsPointLeftOfLine(points[j], points[pointOnHull], points[endpoint])) ? j : endpoint;
}
pointOnHull = endpoint;
} while (endpoint != hullIndices[0]); // wrapped around to first hull point
CreateOrResizeNativeArrayIfNecessary <Vector2>(hullIndices.Length, allocator, ref convexHullOut);
for (int i = 0; i < hullIndices.Length; ++i)
{
convexHullOut[i] = points[hullIndices[i]];
}
}
}
internal Enumerator(NativeFixedList <T> list)
{
m_Index = -1;
m_NativeFixedList = list;
}
public bool Equals(NativeFixedList <T> other)
{
return
(m_NativeArray.Equals(other.m_NativeArray) &&
(Length == other.Length));
}