How 2D Game Collision Works (Separating Axis Theorem)

I recently added Separating Axis Theorem to my game engine, which is an approach for working out 2D collision.

Thanks to my colleagues for listening to an early draft of this video.

Resources
Shapes on a Grid: https://www.bbc.co.uk/bitesize/topics...
Vectors:    • Vectors - Equation of a Line :  Intro...  
Unit Vectors:    • Vectors : Unit Vectors : ExamSolutions  
Vector Dot Product:    • Vectors : Scalar or Dot Product : Exa...  

Dot Product Proof:    • Shortest distance of a point to a lin...  

Contents
0:00 Hello
0:38 Separating Axis Theorem
1:28 Basic Rectangle Checks
2:26 Rotated Rectangles
3:08 Misaligned Rotations
4:07 Finding Axes
5:02 Other Shapes
5:31 Circles
6:01 Concave Shapes
6:22 Summary