protected NurbsBase(int degree, KnotVector knots, List <Point4> controlPoints)
{
if (controlPoints is null)
{
throw new ArgumentNullException(nameof(controlPoints));
}
if (knots is null)
{
throw new ArgumentNullException(nameof(knots));
}
if (degree < 1)
{
throw new ArgumentException("Degree must be greater than 1!");
}
if (knots.Count != controlPoints.Count + degree + 1)
{
throw new ArgumentException("Number of controlPoints + degree + 1 must equal knots length!");
}
if (!knots.IsValid(degree, controlPoints.Count))
{
throw new ArgumentException("Invalid knot format! Should begin with degree + 1 repeats and end with degree + 1 repeats!");
}
Weights = Point4.GetWeights(controlPoints);
Degree = degree;
Knots = knots;
ControlPointLocations = Point4.PointDehomogenizer1d(controlPoints);
ControlPoints = controlPoints;
}
/// <summary>
/// Defines the NURBS form of the polyline.
/// </summary>
private void ToNurbsForm()
{
if (_segments.Count == 1)
{
Weights = Point4.GetWeights(_segments[0].ControlPoints);
Degree = _segments[0].Degree;
Knots = _segments[0].Knots;
ControlPointLocations = Point4.PointDehomogenizer1d(_segments[0].ControlPoints);
ControlPoints = _segments[0].ControlPoints;
return;
}
// Extract the biggest degree between the curves.
int finalDegree = _segments.Max(c => c.Degree);
// Homogenized degree curves.
IEnumerable <NurbsBase> homogenizedCurves = _segments.Select(curve => curve.Degree != finalDegree ? Modify.Curve.ElevateDegree(curve, finalDegree) : curve);
// Join curves.
List <double> joinedKnots = new List <double>();
List <Point4> joinedControlPts = new List <Point4>();
joinedKnots.AddRange(homogenizedCurves.First().Knots.Take(homogenizedCurves.First().Knots.Count - 1));
joinedControlPts.AddRange(homogenizedCurves.First().ControlPoints);
foreach (NurbsBase curve in homogenizedCurves.Skip(1))
{
joinedKnots.AddRange(curve.Knots.Take(curve.Knots.Count - 1).Skip(finalDegree + 1).Select(k => k + joinedKnots.Last()).ToList());
joinedControlPts.AddRange(curve.ControlPoints.Skip(1));
}
// Appending the last knot to the end.
joinedKnots.Add(joinedKnots.Last());
Weights = Point4.GetWeights(joinedControlPts);
Degree = finalDegree;
Knots = joinedKnots.ToKnot().Normalize();
ControlPointLocations = Point4.PointDehomogenizer1d(joinedControlPts);
ControlPoints = joinedControlPts;
}