Bullet Game is our near-end stage pygame 2d game framework example. We've already done at least 6 or 7 other games using pygame. So this will document the patterns we have learned.

We began by “just writing” a game, then the second part was refactoring the game. I wanted to make refactoring it's own project. What are the goals of this refactoring?

• Refactoring
  • Encapsulation

The primary goal is encapsulation. So, we're going to break up the old main into several new classes.

The first thing we always do is have a Screen class and a Window class. The Screen class defines things like WIDTH and HEIGHT, and the Window class holds the pygame screen and other pygame initialization.

Initially, this code would appear at the start of a main.py. Later we moved it into class Game's init. However, to keep things clean we made it into it's own class.

This calls pygame.init(). See main

import pygame

class Window:
    def __init__(self):
        pygame.init()

    def setLogo(self, filename):
        self.logo = pygame.image.load(filename)
        pygame.display.set_icon(self.logo)
        return self.logo

    def setCaption(self, cap):
        pygame.display.set_caption(cap)

    def setSize(self, width, height):
        self.width = width
        self.height = height
        self.size = (width, height)
        self.screen = pygame.display.set_mode(self.size)
        return self.screen

    def setFont(self, filename, size):
        pygame.font.init()
        self.font = pygame.font.Font(filename, size)

        font_width, font_height = self.font.size("@")
        self.fontwidth = font_width
        self.fontheight = size

        return self.font