How to slove this problem?I am in trouble.

I am programing a CNC ToolPath Simulation.
In the programe ,I am aksed to display the toolpath and the axis of the tool.
(It is just like I use a pen draw some line in the paper,I want to display the line and the pen is moving)
Because the data is preety huge, so i don’t use Buffer to store those data.
So if i am not rerender sence,how can i display
the movement of the Axis of the tool?

thanks a lot.

Maybe I misunderstood your question but:

If you dont want to redraw everything simply dont clear the colorbuffer, this way your colorbuffer will be updated in a incremental fashion.