/// <summary>
/// Get the normal for the polygon.
/// May be optimized for PolyAdv.
/// </summary>
/// <param name="poly"></param>
/// <returns></returns>
public static Vector3 GetNormal(this IPoly poly)
{
if (poly is IPolyExtensionNormal)
{
return(((IPolyExtensionNormal)poly).AdvGetNormal());
}
else if (poly is IPolyForwarder)
{
return(((IPolyForwarder)poly).GetPoly().GetNormal());
}
else
{
return(poly.CalcNormal());
}
}