Raspberry Pi User Guide

Appendix A: Python Recipes

The following recipes provide the program code for Example 3 and Example 4 in Chapter 11, “An Introduction to Python”, and a sample solution for the combined input-output program suggested in Chapter 12, “Hardware Hacking”. Each recipe is also available for download from the Raspberry Pi User Guide website at http://www.wiley.com/go/raspberrypiuserguide. If you’re typing the code in by hand, look out for the symbol: this indicates that the line is wrapped due to space constraints in the book. If you see the symbol at the end of a line, don’t press Enter until you reach the end that doesn’t have a symbol present.

Raspberry Snake (Chapter 11, Example 3)

#!/usr/bin/env python

# Raspberry Snake

# Written by Gareth Halfacree for the Raspberry Pi User Guide

import pygame, sys, time, random

from pygame.locals import *

pygame.init()

fpsClock = pygame.time.Clock()

playSurface = pygame.display.set_mode((640, 480))

pygame.display.set_caption(‘Raspberry Snake’)

redColour = pygame.Color(255, 0, 0)

blackColour = pygame.Color(0, 0, 0)

whiteColour = pygame.Color(255, 255, 255)

greyColour = pygame.Color(150, 150, 150)

snakePosition = [100,100]

snakeSegments = [[100,100],[80,100],[60,100]]

raspberryPosition = [300,300]

raspberrySpawned = 1

direction = ‘right’

changeDirection = direction

def gameOver():

    gameOverFont = pygame.font.Font(‘freesansbold.ttf’, 72) ...