protected override void ComputeTangents()
{
if (ControlPoints.Count == 1)
{
tangents.Add(Vector3.Zero);
return;
}
if (ControlPoints.Count == 2)
{
Vector3 tangent = ControlPoints[1].Value - ControlPoints[0].Value;
tangents.Add(tangent);
tangents.Add(tangent);
return;
}
Vector3 tangentA, tangentB;
Vector3 previous, current, next;
//First endpoint
current = ControlPoints[0].Value;
next = ControlPoints[1].Value;
Vector3.Subtract(ref next, ref current, out tangentA);
Vector3.Multiply(ref tangentA, .5f / (ControlPoints[1].Time - ControlPoints[0].Time), out tangentA);
//Vector3.Multiply(ref current, .5f / (controlPoints[0].time), out tangentB);
//Vector3.Add(ref tangentA, ref tangentB, out tangentA);
tangents.Add(tangentA);
for (int i = 1; i < ControlPoints.Count - 1; i++)
{
previous = current;
current = next;
next = ControlPoints[i + 1].Value;
Vector3.Subtract(ref next, ref current, out tangentA);
Vector3.Subtract(ref current, ref previous, out tangentB);
Vector3.Multiply(ref tangentA, .5f / (ControlPoints[i + 1].Time - ControlPoints[i].Time), out tangentA);
Vector3.Multiply(ref tangentB, .5f / (ControlPoints[i].Time - ControlPoints[i - 1].Time), out tangentB);
Vector3.Add(ref tangentA, ref tangentB, out tangentA);
tangents.Add(tangentA);
}
previous = current;
current = next;
Vector3.Negate(ref current, out tangentA);
Vector3.Subtract(ref current, ref previous, out tangentB);
int currentIndex = ControlPoints.Count - 1;
int previousIndex = currentIndex - 1;
//Vector3.Multiply(ref tangentA, .5f / (-controlPoints[currentIndex].time), out tangentA);
Vector3.Multiply(ref tangentB, .5f / (ControlPoints[currentIndex].Time - ControlPoints[previousIndex].Time), out tangentB);
//Vector3.Add(ref tangentA, ref tangentB, out tangentA);
tangents.Add(tangentB);
}
}
