3D Rotations with Quaternions (or Rotors) in Game Dev

An introduction into how quaternions (or rotors) can be used in your game code to handle object orientation.
This video was made to be paused and rewound! If you feel like I'm going too fast, it's not you, it's by design (pausing/rewinding is easier than trying to skip ahead and over/undershooting it)

- LINKS -

2D Game Demo:

Euler Game Demo:

Rotation Tool:

Combined Rotation Tool:

Quaternion Multiplication:

Combining Rotations:

Complete Game Demo:

3Blue1Brown Video:

Quaternions and 3D Spatial Rotations Wikpedia Article:

Rotor Video:

Miegakure Trailer (by the maker of the above rotor video... it's not related at all, but it looks really cool, so I'm linking that here as well)

Timecodes:
0:00 Intro
0:42 How to program Rotation
3:30 Exploration of 3D Rotations
8:09 What are Quaternions?
11:48 Quaternions for Rotation
15:05 Game Code with Quaternions
17:34 How do Quaternions/Rotors work?
19:14 Shameless Begging

Extra crap that may or may not improve this videos search rankings:
A guide for game developers who want to make a game, with or without a game engine, that shows how quaternions work for 3D rotations. It also has rotors, though not as many people will search for that. This is for game developers who have an interest in game dev, and other key words related to game development. Quaternions are useful for graphics, specifically 3D graphics, about which I am writing in a completely organic matter in order for googles algorithm to maybe associate this video with more search terms. Personally, I think it's ridiculous that google openly promotes and accepts the idea of SEO instead of penalizing people that do it... thank god they lost that court case and are now considered a monopoly, maybe it'll open search up to competition and the internet won't be the swamp of SEO optimized garbage that it is today. But until then, let me try to jam more search terms into this text that no one will ever read. What else are quaternions useful for, besides their applications in game development and graphics? It's not only game devs that use quaternions for making 3D video games, other people use them too... like mathematicians, who aren't developing games. Astronauts used quaternions to fly to the moon, which had nothing to do with 3D game development or game programming; their rockets usually use a rocket engine, not a game engine, so the rockets were using quaternions without a game engine, and they got all the way to the moon. Pink Floyd once sang about the dark side of the moon. Emperor Palpatine also talked about the dark side a lot. Apparently he was in that third Star Wars sequel movie, which I didn't bother to see, but man from what I read it sounded awful. Ugh, there goes my ADHD again. What was I writing about? Oh yeah, how quaternions are useful for making 3D digital entertainment products, and performing 3D rotations, whether for an application that has 3D graphics, or a game that is made without a game engine, or even with a game engine, because quaternions and rotations are very useful in game dev. Game dev game dev yay yay yay, I do game dev every day, hurray.