Detects when the node is visible on screen. The VisibilityNotifier3D detects when it is visible on the screen. It also notifies when its bounding rectangle enters or exits the screen or a [Camera3D]'s view. If [code]true[/code], the bounding box is on the screen. [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. The VisibilityNotifier3D's bounding box. Emitted when the VisibilityNotifier3D enters a [Camera3D]'s view. Emitted when the VisibilityNotifier3D exits a [Camera3D]'s view. Emitted when the VisibilityNotifier3D enters the screen. Emitted when the VisibilityNotifier3D exits the screen.