So, in my 2D game I push render commands to a list, then order them by z, and then execute them from farthest to closest. I wonder if I should worry about overdraw.
In my case I guess I'll have an average of 3 to 4 overdraws per pixel. I always clear the background to sky blue, that's already filling each pixel; then I draw clouds, then terrain, then entities, then UI. So maybe I could do a custom system that can clip some of those elements, at least the background fill, looking at the closer layers. Would that be reasonable, or a complete overkill?
I won't have complex shaders, so I guess that buys me some GPU compute. If I were to have shaders, they'd be simple effects applied at the end to each pixel, or applied to a separate blank texture, which would then merge with the main buffer, so this way the expensive part (either the merging, or the drawing into the lighting texture) would only be done once, and the overdraw would be cheap. Is this generally a good enough approach, just trying to avoid overdraw with the more complex shaders?