The VisibleOnScreenNotifier2D detects when it is visible on the screen. It also notifies when its bounding rectangle enters or exits the screen or a viewport.
If you want nodes to be disabled automatically when they exit the screen, use [VisibleOnScreenEnabler2D] instead.
[b]Note:[/b] VisibleOnScreenNotifier2D uses the render culling code to determine whether it's visible on screen, which also means that its [member CanvasItem.visible] must be [code]true[/code] to work correctly.
[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.