/// <summary>
/// Non Rational B-Spline curve point
/// </summary>
/// <param name="u">interval parameter 0 ≦ u ≦ 1</param>
/// <returns></returns>
public GPoint NonRationalBSpline(double u)
{
int span = NURBS.FindSpan(Degree, u, KnotVector);
double[] basisFuns = NURBS.BasisFuns(span, Degree, KnotVector, u);
double x = 0.0;
double y = 0.0;
for (int i = 0; i <= Degree; i++)
{
x += basisFuns[i] * ControlPoints[span - Degree + i].X;
y += basisFuns[i] * ControlPoints[span - Degree + i].Y;
}
return(new GPoint(x, y));
}
/// <summary>
/// Rational B-Splines (NURBS) curve
/// </summary>
/// <param name="u">interval parameter 0 ≦ u ≦ 1</param>
/// <returns>curve point at u</returns>
public GPoint RationalBSpline(double u)
{
int span = NURBS.FindSpan(Degree, u, KnotVector);
double[] basisFuns = NURBS.BasisFuns(span, Degree, KnotVector, u);// CalcBasisFuns(span, u);
double x = 0;
double y = 0;
double rationalWeight = 0.0;
for (int i = 0; i <= Degree; i++)
{
GPoint cp = ControlPoints[span - Degree + i];
x += basisFuns[i] * cp.X * cp.W;
y += basisFuns[i] * cp.Y * cp.W;
rationalWeight += basisFuns[i] * cp.W;
}
return(new GPoint(x / rationalWeight, y / rationalWeight));
}
