Vector3 getGradientAtT(float t)
{
int i0 = 0, i1 = 0, i2 = 0, i3 = 0; // indices
if (closed)
{
i0 = ((int)t) % points.Count;
int add = (int)t;
if (curveType == CurveType.Bezier && add >= 1)
{
i0 = (3 * add) % points.Count;
}
i1 = (i0 + 1) % points.Count;
i2 = (i1 + 1) % points.Count;
i3 = (i2 + 1) % points.Count;
}
else
{
i0 = 0;
i1 = 1;
i2 = 2;
i3 = 3;
}
// Debug.Log("i0 " + i0 + ", i1 " + i1 + ", i2 " + i2 + ", i3 " + i3);
CurveSegment csX = new CurveSegment(curveType, points[i0].position.x, points[i1].position.x, points[i2].position.x, points[i3].position.x);
CurveSegment csY = new CurveSegment(curveType, points[i0].position.y, points[i1].position.y, points[i2].position.y, points[i3].position.y);
CurveSegment csZ = new CurveSegment(curveType, points[i0].position.z, points[i1].position.z, points[i2].position.z, points[i3].position.z);
float dv_x = csX.EvaluateDv(t);
float dv_y = csY.EvaluateDv(t);
float dv_z = csZ.EvaluateDv(t);
Vector3 dv_p = new Vector3(dv_x, dv_y, dv_z);
//Vector2 dv_p = new Vector2(dv_x, dv_y);
return(dv_p);
}