[vtkusers] How to setup a graphical pipeline for 2D multi-layered rendering

[Elvis Dowson]

Hi,
         I'd like some help to figure out how I can go about setting  
up a graphical pipeline as follows:

a. Layer 0 to display a flat 2D map
b. Layer 1 to display a graphic object ( say a small cone)
c. Layer 2 to display some 2D text

The graphic objects and the text will be superimposed over the map.

I would like to setup the graphics pipeline in such a way that each  
layer is updated independently in a separate thread of execution.

For example, the cone graphic object keeps moving around the map,  
while the 2D text object follows it around and displays the current  
direction the cone is heading (e.g. North, East, West, South).

Best regards,

Elvis Dowson