Introduction to pygame

Pygame is a set of Python modules designed for writing video games. It adds functionality on top of the excellent SDL library, enabling you to create fully-featured games and multimedia programs in the Python language. It's key benefits include:

• Beginner-Friendly: Simple Python syntax makes it ideal for newcomers.
• Active Community: Rich with tutorials, examples and global support.
• Cross-Platform: Works on Windows, Mac and Linux.
• Versatile: Suitable for games, simulations and interactive apps.
• Free & Open Source: No cost, no restrictions.

Installing Pygame

Pygame requires Python 3.6.1 or later, as newer versions are more beginner-friendly and offer improved performance. If you don’t have Python installed, download it from python.org. 

To install Pygame, use the following command:

python3 -m pip install -U pygame --user

After installation, verify if it works by running a built-in example:

python3 -m pygame.examples.aliens

If the game launches successfully, you are ready to start using Pygame!

Creating your first pygame program

Once Pygame is installed, let’s create a simple program that displays four squares on the screen.

Importing Pygame Modules

# Import the pygame module

import pygame

# Import constants for easier access to key events

from pygame.locals import *

Before using any Pygame functionality, we need to import its modules.

Understanding key pygame concepts

• Sprite: A 2D object (like our square) displayed on the screen.
• Surface: A canvas for drawing (even the screen is a Surface).
• Rect: A rectangle object for positioning and collisions.

Implementation code:

import pygame
from pygame.locals import *

class Sq(pygame.sprite.Sprite):
    def __init__(self):
        super().__init__()
        self.surf = pygame.Surface((25, 25))
        self.surf.fill((0, 200, 255))

pygame.init()  # Init Pygame
win = pygame.display.set_mode((800, 600)) # Game window 800x600

# Create 4 squares
s1, s2, s3, s4 = Sq(), Sq(), Sq(), Sq()

# Game loop
run = True
while run:
    for e in pygame.event.get():
        if e.type == QUIT or (e.type == KEYDOWN and e.key == K_BACKSPACE):
            run = False

    # Draw squares in corners
    win.blit(s1.surf, (40, 40))
    win.blit(s2.surf, (40, 530))
    win.blit(s3.surf, (730, 40))
    win.blit(s4.surf, (730, 530))

    pygame.display.flip()

Output

Explanation:

• Sq class creates a 25x25 light blue square sprite in Pygame by extending pygame.sprite.Sprite, initializing the parent class, and filling the surface with color (0, 200, 255).
• pygame.event.get() handles all incoming events. If the event type is QUIT, the game exits when the window close button is clicked. Similarly, if a KEYDOWN event occurs and the Backspace key is pressed (e.key == pygame.K_BACKSPACE), the game will exit.
• win.blit(s1.surf, (40, 40)) draws square 1 at the top-left, s2 at the bottom-left, s3 at the top-right and s4 at the bottom-right.
• pygame.display.flip() updates the screen to show the drawn squares.

Catch the falling blocks mini game

Let’s create a simple, real game where a player-controlled paddle catches falling blocks. Its features include:

• Move the paddle left/right using the arrow keys.
• Catch falling blocks to earn points.
• Game Over if a block hits the ground.

import pygame
import random
import sys

pygame.init() # Init pygame
W, H = 600, 600 # Screen setup

screen = pygame.display.set_mode((W, H))
pygame.display.set_caption("Catch the Falling Blocks")

WHT, BLU, RED, BLK = (255, 255, 255), (0, 200, 255), (255, 0, 0), (0, 0, 0) # Colors

# Clock and font
clock = pygame.time.Clock()
font = pygame.font.SysFont(None, 36)

# Paddle and block
paddle = pygame.Rect(W // 2 - 60, H - 20, 120, 10)
block = pygame.Rect(random.randint(0, W - 20), 0, 20, 20)
b_speed = 5

score = 0 # Score

# Game loop
run = True
while run:
    screen.fill(BLK)

    for e in pygame.event.get():
        if e.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

    # Paddle movement
    keys = pygame.key.get_pressed()
    if keys[pygame.K_LEFT] and paddle.left > 0:
        paddle.move_ip(-8, 0)
    if keys[pygame.K_RIGHT] and paddle.right < W:
        paddle.move_ip(8, 0)

    # Move block
    block.y += b_speed

    # Block caught
    if block.colliderect(paddle):
        block.y = 0
        block.x = random.randint(0, W - 20)
        score += 1
        b_speed += 0.5  # Speed up

    # Block missed
    if block.y > H:
        game_over = font.render(f"Game Over! Final Score: {score}", True, RED)
        screen.blit(game_over, (W // 2 - 150, H // 2))
        pygame.display.flip()
        pygame.time.wait(2000)
        run = False

    # Draw objects
    pygame.draw.rect(screen, WHT, paddle)
    pygame.draw.rect(screen, BLU, block)

    # Display score
    score_text = font.render(f"Score: {score}", True, WHT)
    screen.blit(score_text, (10, 10))

    pygame.display.flip()
    clock.tick(60)

Output

Explanation:

• pygame.Rect(...) used to define rectangular shapes like the paddle and block. The first two values are the top-left (x, y) position, followed by width and height.
• paddle.move_ip(x, y) moves the paddle in-place by given values.
• block.colliderect(paddle) checks for collision between block and paddle. If True, the block is "caught".
• score & b_speed score is increased by 1 on each catch and the block speed increases, making the game progressively harder.
• pygame.display.flip() updates the entire screen with any changes made e.g., moving paddle or falling block.
• clock.tick(60) keeps the game running at 60 frames per second for smooth movement.