I uploaded these tutorial videos on YouTube & Vid.me a while ago. I apologize for neglecting posting about it here sooner.
If you are unfamiliar about the Cannon Shooter; It is a short tutorial series about implementing shooting mechanic in Godot Engine. This includes setting up collision, physics and fun extras such as using Tool script to preview bullet path and, soon in part 4, hitting enemies.

Part 2 – Ball Physics

Part 3 – Tool Script

VisibilityNotifier is commonly used when you wish to activate or deactivate certain nodes when they come into view. An example of this may be to disable bullets when they leave the screen. By manipulating the VisibilityNotifier size, you can make it signal a while before entering the screen, or a while after the screen – so that you wont see half a bullet, ball or object disappear before truly having left the screen.

In this video, I will demonstrate how you can use the VisibilityNotifier2D node. What we are doing in this video can also be done using the 3D version of the node; “VisibilityNotifier”.

​​​​​​​

I have to say, making this video has been tough. And no, it is not what you might think. It is because I am using a new video editor; Blender.
Blender is amazing and weird. Frankly, I am not sure if it is up to the task. Simple actions such as adding text on the screen is a chore. The same goes with manipulating tracks. 
Although I am all for open sourced software, and more than willing to learn how to use it.

This is the result so far; part 1 out of N tutorial videos, where I will be covering how you can handle shooting.