pub fn make_periodic_bspline(
degree: usize,
control_points: &[Vec3],
) -> Result<NurbsCurve, String>Expand description
The closed, periodic uniform B-spline of degree on the control polygon
control_points (each given once; the polygon closes from the last to the
first), as a clamped curve over [0, n] for n control points.
The periodic curve is the B-spline of the polygon wrapped round by
degree points on evenly spaced knots, taken over one period. Its two ends
are clamped there by knot insertion, which moves no point of the curve: the
result has the same n polynomial spans, joined as smoothly as the
periodic curve joins them (C^(degree−1)), and starts and ends at the same
point with the same derivatives.