public Vector4 DecompressVector3(Vector3 v)
{
Vector4 r = new Vector4(v.X, v.Y, v.Z, 0);
float l = r.LengthSq();
if (l == 0)
r.W = -1;
else if (l > 0 && l < 1.0f)
r.W = (float)Math.Sqrt(1f - r.X * r.X - r.Y * r.Y - r.Z * r.Z) * -1f;
return r;
}
