void Draw(Program program, Vector3 viewPoint, ref Matrix4d world)
{
if (program == null)
{
throw new ArgumentNullException();
}
CleanTree();
terrain.ClearInstanceArray();
throw new NotImplementedException();
/*viewPoint = Vector3.Transform(viewPoint, Matrix.Invert(world));
* treeRoot.Batch(ref viewPoint);
*
* DrawInstances(program);*/
}