PyGame

Pygame is a cross platform tool to easily develop games in Python.

It is a set of python module that is built on top of the SDL (Simple DirectMedia Layer) library that allows for developers to have low level access to common gaming tools of audio, peripherals and graphics.

For more information about the Pygame module, please see it's wiki page.

Install

PyGame can be installed using pip.

Virtual environment

Remember to set up and activate our virtual environment before we start:

$ python3 -m venv venv

On Windows, run:

$ venv\Scripts\activate.bat

On Unix or MacOS, run:

$ source venv/bin/activate

Installation

If you would like to install a specific version, please see: https://github.com/pygame/pygame/releases.

For Mac users on Cantalina OS, you will need to install the 2.0.x.dev version.

(venv) $ pip3 install pygame==2.0.0.dev6

Test your installation by calling the example that comes with the package:

The key here is that it brings up a GUI game.

(venv)$ python3 -m pygame.examples.aliens

PyGame Basics

NOTE: PyGame, at least the GUI part, is not usable (or testable) within jupyter notebooks.

So we will use scripts. Let's start with a script and let's name it 'game.py'.

Load pygame and initialise

To use pygame, lets import the package.


            # game.py
import pygame

and we need to initalise pygame to use the library.

We do this in our class, Game:


            class Game():
    def __init__(self):
        pygame.init()
  
if __name__ == "__main__":
    game = Game()

Game display surface area

Next we create our game screen, and call it display surface:


            # Dimensions
WIDTH = 640
HEIGHT = 480

class Game():
    def __init__(self):
        pygame.init()
        self.size = WIDTH, HEIGHT
        self.display = pygame.display.set_mode(self.size)
        self.disp_surf = self.init_display()
  
    def init_display(self):
        # Create surface
        disp_surf = pygame.Surface(self.size)
        return disp_surf.convert()

The display surface is our game play surface area, where we load onto the screen when the game runs.

Events

And any game will require user input in some form or another, let us now add the codes to check for trigger to close the game. (user clicking the red cross icon on top corner of our display surface)

First we add a running flag to only loop when we have successfully initialised our display surface.


            class Game():
    def __init__(self):
        pygame.init()
        self.size = WIDTH, HEIGHT
        self.display = pygame.display.set_mode(self.size)
        self.disp_surf = self.init_display()
        self.running = True if self.disp_surf else False

We then add an execute function to perform the loop.


            class Game():
    def __init__(self):
        pygame.init()
        self.size = WIDTH, HEIGHT
        self.display = pygame.display.set_mode(self.size)
        self.disp_surf = self.init_display()
        self.running = True if self.disp_surf else False
  
    def execute(self):
        # Event loop
        while self.running:
            self.check_events()
        return
      
    def check_events(self):
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                self.running = False
                return
        return

The check_events() function will take care of checking if the user has hit the red cross, and quit the game when that happens.

The codes check all the events for the game, if it gets the event pygame.QUIT, it exits the loop.

Now we just need to execute the codes.


            if __name__ == "__main__":
    game = Game()
    game.execute()

Test it

Test your codes by calling the module from console:

And hit the red cross button, it should exit our game and quit. Top left for Macs and Unix, top right for Windows.

python3 -m game

This is the quick show of what is required to use PyGame.