Okay, so I'm making a HUD for my game, which controls a lot like a PC RTS (right click on map to move unit, etc) and so the map shouldn't receive mouse events "under" the UI. That's simple enough with mouse filtering, alright.
Thing is, my HUD has this shape where you can see the map through a "cut" in the inner border (pictured below), but Godot seemingly only assumes the total area of my HUD's texture to be it's collision area and will either filter nothing at all, or block clicks done on the map through this cut.

Is there some way of defining the shape of a Control node's filter area? So far the only idea that comes to mind would be making a polygon 2D collider that follows the camera, and that seems way too hacky...