I'm looking to develop a post-render diagnostics overlay and am not quite sure how to go about it.
I can add an opengl overlay to the viewport fine with the SpaceView3D draw_handler_add, but this of course will not show in the renderer.
How can I add this to the render result?
Ideally it would be great to have a custom opengl pass but not sure how to go about that in python.
I know I can just add this to the blender source in C, but I'd like to avoid modifying the source as much as possible in case I decide to distribute the addon.
Thanks!