📘 Overview

• What is it?: Pygame is a cross-platform set of Python modules designed for writing video games. It includes computer graphics and sound libraries designed to be used with the Python programming language, acting as a high-level wrapper over SDL (Simple DirectMedia Layer).
• Key Features:
  • Simple Game Loop: Standard paradigm handling events, game states, and rendering.
  • 2D Graphics: Fast loading and drawing of images (Surfaces) and handling coordinate spaces (Rects).
  • Collision Handling: Easy bounding box and circle-based collision checks.
  • Input handling: Built-in support for keyboard, mouse, and game controllers.
• Installation:

  pip install pygame

🧾 Core Concepts

• Game Loop: The continuous cycle that runs while the game is open. It handles:
  • 1. Input events (polling keyboard/mouse).
  • 2. Game logic updates (updating positions, checking collisions).
  • 3. Rendering (clearing screen, drawing sprites, flipping display).
• Surfaces: Objects representing images. The main window is a Surface, and characters/backgrounds are drawn onto it.
• Rect: A rectangle object used to store and manipulate rectangular areas (coordinates, widths, heights) - crucial for movement and collision detection.

💻 Common Code Patterns & Cheat Sheet

• Basic Game Window & Loop:

  import pygame
  import sys
   
  # Initialize all Pygame modules
  pygame.init()
   
  # Setup screen
  screen = pygame.display.set_mode((800, 600))
  pygame.display.set_caption("My Pygame Game")
   
  # Clock to limit FPS
  clock = pygame.time.Clock()
   
  # Game Loop
  running = True
  while running:
      # 1. Event Polling
      for event in pygame.event.get():
          if event.type == pygame.QUIT:
              running = False
              
      # 2. Logic Updates
      # (update sprite positions, check collisions, etc.)
      
      # 3. Drawing
      screen.fill((0, 0, 0))  # Clear screen with black background
      
      # Redraw display
      pygame.display.flip()
      
      # Cap framerate to 60 FPS
      clock.tick(60)
      
  pygame.quit()
  sys.exit()

• Handling Keyboard Input & Movement:

  # Inside the game loop:
  keys = pygame.key.get_pressed()
   
  # Move player rectangle
  player_rect = pygame.Rect(100, 100, 50, 50)
  speed = 5
   
  if keys[pygame.K_LEFT]:
      player_rect.x -= speed
  if keys[pygame.K_RIGHT]:
      player_rect.x += speed
  if keys[pygame.K_UP]:
      player_rect.y -= speed
  if keys[pygame.K_DOWN]:
      player_rect.y += speed

• Drawing Shapes & Checking Collisions:

  # Draw red player rectangle
  pygame.draw.rect(screen, (255, 0, 0), player_rect)
   
  # Create enemy rectangle
  enemy_rect = pygame.Rect(300, 300, 50, 50)
  pygame.draw.rect(screen, (0, 0, 255), enemy_rect)
   
  # Check AABB (Axis-Aligned Bounding Box) collision
  if player_rect.colliderect(enemy_rect):
      print("Collision detected!")

💡 Best Practices & Tips

• Framerate Independence: Use Delta Time (dt = clock.tick(60) / 1000.0) to scale movements, ensuring they run at the same speed on different CPU speeds.
• Asset Preloading: Load all images and sound files once outside the game loop. Loading files inside the game loop causes significant performance drop.
• Coordinate Space: Always use Pygame Rect objects to manage positions. They provide useful attributes like .center, .top, .bottom, .left, .right for easy alignment.

🔗 Navigation & Internal Links

• Parent: Python
• Related Notes: Game Development | Simple DirectMedia Layer | Simple and Fast Multimedia Library