/// <summary>
/// Get item enumerator based on viewpoint
/// </summary>
/// <param name="point"></param>
/// <returns></returns>
public IEnumerable <T> Select(Point3D viewpoint)
{
Halfspace halfspace = partition.Classify(viewpoint);
if (halfspace == Halfspace.Negative)
{
if (front != null)
{
foreach (var item in front.Select(viewpoint))
{
yield return(item);
}
}
}
else if (back != null)
{
foreach (var item in back.Select(viewpoint))
{
yield return(item);
}
}
foreach (var item in items)
{
yield return(item);
}
if (halfspace == Halfspace.Negative)
{
if (back != null)
{
foreach (var item in back.Select(viewpoint))
{
yield return(item);
}
}
}
else if (front != null)
{
foreach (var item in front.Select(viewpoint))
{
yield return(item);
}
}
}
public void OnTick(object sender, EventArgs e)
{
if (tree != null)
{
var viewpoint = camera.GetRotationMatrix().Transform(camera.Position);
var items = tree.Select(viewpoint).ToArray();
var animated = ApplyAnimation();
var reordered = Reorder(items);
if (animated || reordered || needsRefresh)
{
Refresh(items, viewpoint);
}
}
timer.Begin();
}