Introduction

Reimplementation of Alien Invasion from the book Python Crash Course.

I changed the graphics and refactored the code to showcase design patterns as a teaching tool. I also added multiple guns.

Some power-ups are planned in the future.

To start the code simply run python space_invaders.py

Used patterns

Pattern	Place
Factory	Guns abstract bullet creation from the game logic
Strategy	Different guns change bullet creation logic
Composite	Pygame Group object is a composite of Sprites
Prototype	Used to copy rectangles for Splitter Bullets
Listener	Used to update scoreboard based on game events
Iterator	Used to iterate over various collections with for
Decorator	Used to combine various bullet behaviours on hit
Singleton	Used to allow only one stats object