The VisibilityNotifier detects when it is visible on the screen. It also notifies when its bounding rectangle enters or exits the screen or a [Camera]'s view.
[b]Note:[/b] VisibilityNotifier uses an approximate heuristic for performance reasons. It doesn't take walls and other occlusion into account (unless you are using [Portal]s). The heuristic is an implementation detail and may change in future versions. If you need precise visibility checking, use another method such as adding an [Area] node as a child of a [Camera] node and/or [method Vector3.dot].
[b]Note:[/b] It takes one frame for the node's visibility to be assessed once added to the scene tree, so this method will return [code]false[/code] right after it is instantiated, even if it will be on screen in the draw pass.