Chapter 1.5 :when the room is made to x = 0 or y = 0, the Fov is not delivered.

As you can see in the image below, when the room is made to (x = 0 or y = 0) (example: ` let test_room = Rect::new(0, 0, 30, 30);`), Fov is not reached. It seems to me that the top left wall should be visible.


I saw the source code of `thebracket-lib`, and the function of `field_of_view` was originally supposed to [start from x>0 or y>0](https://github.com/thebracket/bracket-lib/blob/master/bracket-pathfinding/src/fieldofview.rs#L113). Is there any reason for that?

P,S.

I'm using machine translation, so please forgive me for the weird English :( .