I am trying to achieve the following: print a changing text part of a sprite and update it every frame.
The sprite is a simple transparent rectangular area surounded by red edges.
At the center of that area a number is printed and that number change over time.
I would like to use the dirty rectangle method.
I haven't managed yet to make it work in my game but I have reproduce the scenario in a simple code attached to that post feel free to run it
If you could tell me what is wrong in my code that would be great.