public static Sphere FromPoints(Vector3[] points, BoundingSphereAlgorithm algorithm)
{
switch (algorithm)
{
case BoundingSphereAlgorithm.FromBounds:
{
var bounds = AABBox.FromPoints(points);
return(new Sphere(bounds.Center, bounds.Extents.magnitude));
}
case BoundingSphereAlgorithm.Average:
{
Vector3 sum = Vector3.zero;
foreach (var v in points)
{
sum += v;
}
sum /= points.Length;
float dist = 0f;
float d;
foreach (var v in points)
{
d = (v - sum).sqrMagnitude;
if (d > dist)
{
dist = d;
}
}
dist = Mathf.Sqrt(dist);
return(new Sphere(sum, dist));
}
case BoundingSphereAlgorithm.Ritter:
{
Vector3 xmin, xmax, ymin, ymax, zmin, zmax;
xmin = ymin = zmin = Vector3.one * float.PositiveInfinity;
xmax = ymax = zmax = Vector3.one * float.NegativeInfinity;
foreach (var p in points)
{
if (p.x < xmin.x)
{
xmin = p;
}
if (p.x > xmax.x)
{
xmax = p;
}
if (p.y < ymin.y)
{
ymin = p;
}
if (p.y > ymax.y)
{
ymax = p;
}
if (p.z < zmin.z)
{
zmin = p;
}
if (p.z > zmax.z)
{
zmax = p;
}
}
var xSpan = (xmax - xmin).sqrMagnitude;
var ySpan = (ymax - ymin).sqrMagnitude;
var zSpan = (zmax - zmin).sqrMagnitude;
var dia1 = xmin;
var dia2 = xmax;
var maxSpan = xSpan;
if (ySpan > maxSpan)
{
maxSpan = ySpan;
dia1 = ymin; dia2 = ymax;
}
if (zSpan > maxSpan)
{
dia1 = zmin; dia2 = zmax;
}
var center = (dia1 + dia2) * 0.5f;
var sqRad = (dia2 - center).sqrMagnitude;
var radius = Mathf.Sqrt(sqRad);
foreach (var p in points)
{
float d = (p - center).sqrMagnitude;
if (d > sqRad)
{
var r = Mathf.Sqrt(d);
radius = (radius + r) * 0.5f;
sqRad = radius * radius;
var offset = r - radius;
center = (radius * center + offset * p) / r;
}
}
return(new Sphere(center, radius));
}
}
return(new Sphere());
}
