/// <summary>
/// 指定の位置の座標を取得。
/// </summary>
protected virtual Vector3 CalcuratePoint(float t)
{
Vector3 linePoint = Vector3.zero;
for (int i = 0; i < this.points.Length; ++i)
{
float bs = BSplineCurve.BSplineBasisFunc(i, this.degree, t, this.knots);
linePoint += bs * this.points[i];
}
return(linePoint);
}
/// <summary>
/// 重みも考慮し、指定の位置の座標を取得。
/// </summary>
protected override Vector3 CalcuratePoint(float t)
{
Vector3 linePoint = Vector3.zero;
float weight = 0f;
for (int i = 0; i < this.points.Length; ++i)
{
float bs = BSplineCurve.BSplineBasisFunc(i, this.degree, t, this.knots);
linePoint += bs * this.weights[i] * this.points[i];
weight += bs * this.weights[i];
}
return(linePoint / weight);
}
/// <summary>
/// Bスプライン基底関数。
/// </summary>
protected static float BSplineBasisFunc(int i, int degree, float t, float[] knots)
{
if (degree == 0)
{
if (t >= knots[i] && t < knots[i + 1])
{
return(1f);
}
else
{
return(0f);
}
}
float w1 = 0f;
float w2 = 0f;
float denominatorA = knots[i + degree] - knots[i];
float denominatorB = knots[i + degree + 1] - knots[i + 1];
if (denominatorA != 0f)
{
w1 = (t - knots[i]) / denominatorA;
}
if (denominatorB != 0f)
{
w2 = (knots[i + degree + 1] - t) / denominatorB;
}
float firstTerm = 0f;
float secondTerm = 0f;
if (w1 != 0f)
{
firstTerm = w1 * BSplineCurve.BSplineBasisFunc(i, degree - 1, t, knots);
}
if (w2 != 0f)
{
secondTerm = w2 * BSplineCurve.BSplineBasisFunc(i + 1, degree - 1, t, knots);
}
return(firstTerm + secondTerm);
}