/// <summary>
/// Compute the 2D convex hull of a set of 3D points in a plane.
/// </summary>
/// <param name="points">A collection of points</param>
/// <param name="planeNormal">The normal direction of the plane in which to compute the hull.</param>
/// <returns>A polygon representing the convex hull, projected along the normal vector to the average depth of the provided points.</returns>
public static Polygon FromPointsInPlane(IEnumerable <Vector3> points, Vector3 planeNormal)
{
if (planeNormal.Length().ApproximatelyEquals(0))
{
throw new ArgumentException("The current normal vector cannot be of length 0");
}
if (planeNormal.Unitized() == Vector3.ZAxis ||
planeNormal.Unitized().Negate() == Vector3.ZAxis)
{
return(FromPoints(points));
}
else
{
var center3D = points.Average();
var toOrientation = new Transform(center3D, planeNormal);
var fromOrientation = toOrientation.Inverted();
var tPoints = points.Select(p => fromOrientation.OfPoint(p)).Select(p => new Vector3(p.X, p.Y));
var twoDHull = FromPoints(tPoints);
return(twoDHull.TransformedPolygon(toOrientation));
}
}