/// <summary>
/// adds a new child scene node
/// the nodes parent property is set automatically
/// </summary>
/// <param name="node">node to add</param>
/// <returns>the added node</returns>
public ISceneNode Attach(ISceneNode node)
{
if (node.IsAttached())
{
throw new GraphicsException("Node is already attached to a root node! Detach first!");
}
if (nodes == null)
{
nodes = new SceneNodes();
}
nodes.Add(node);
node.Parent = this;
node.Manager = Manager;
return(node);
}