/// <summary>
/// Creates circle from three points.
/// </summary>
public Circle2d(V2d a, V2d b, V2d c)
{
var l0 = new Plane2d((b - a).Normalized, (a + b) * 0.5);
var l1 = new Plane2d((c - b).Normalized, (b + c) * 0.5);
if (l0.Intersects(l1, out Center))
{
Radius = (a - Center).Length;
}
else
{
throw new Exception("Cannot construct circle because given points are collinear.");
}
}
/// <summary>
/// Creates an inward hull (i.e. a hull whose normal vectors point
/// inside) from a counter-clockwise enumerated array of polygon
/// points.
/// </summary>
public static Hull2d ToInwardHull(this V2d[] polygon, int pointCount = 0)
{
if (pointCount == 0)
{
pointCount = polygon.Length;
}
var planeArray = new Plane2d[pointCount];
var p0 = polygon[pointCount - 1];
for (int i = 0; i < pointCount; i++)
{
var p1 = polygon[i];
planeArray[i] = new Plane2d((p1 - p0).Rot90.Normalized, p0);
p0 = p1;
}
return(new Hull2d(planeArray));
}
public static bool ApproximateEquals(this Plane2d a, Plane2d b, double tolerance) => ApproximateEquals(a.Normal, b.Normal, tolerance) && ApproximateEquals(a.Distance, b.Distance, tolerance);
public static bool ApproximateEquals(this Plane2d a, Plane2d b) => ApproximateEquals(a, b, Constant <double> .PositiveTinyValue);
public bool Equals(Plane2d other) => Normal.Equals(other.Normal) && Distance.Equals(other.Distance);