BUTTON INVADERS
Space Invaders for your Raspberry Pi push-button controller
https://stuartfoxmusic.com/lab/raspberry-pi-space-invaders-controller/

1. Build the controller and wire it to the Pi as shown in the tutorial.
2. Copy this whole folder to your Pi (keep the fonts, images and sounds
   folders next to buttoninvaders.py).
3. Test your buttons: open buttontest.py in Thonny and click Run.
   Each press should print "Button 1", "Button 2" or "Button 3".
4. Play: open buttoninvaders.py in Thonny and click Run.

   Button 1 = move left    Button 2 = move right    Button 3 = fire / start
   (The arrow keys and space bar still work too. Esc quits.)

If Thonny says "No module named pygame", open a Terminal and type:
   sudo apt install python3-pygame

The changes made for the controller are marked with comments: see lines
12-20, 55-63 and 451-484, plus the start-button code at the very end.

Credits
- Space Invaders game by Lee Robinson (MIT licence, see
  LICENSE-space-invaders.txt) - https://github.com/leerob/space-invaders
- Controller modifications and tutorial by Stuart Fox for the Cotswold
  Raspberry Jam. Tutorial and modifications released into the public domain.
