Pygame Snake, Pt. 1

Source: Dev.to

Introduction

Pygame is a module that lets us create 2D games with Python. It’s a great way to learn programming concepts, and the classic game Snake makes an excellent project for beginners.

When using Pygame, each frame is drawn to an off‑screen buffer (an invisible canvas in memory). After the scene is assembled, the buffer is copied to the on‑screen canvas. Pygame also manages the event loop, allowing us to specify a target frames‑per‑second (FPS) and handling events such as key presses (KEYDOWN) and window closure (QUIT).

Minimal Pygame Setup

Below is a minimal Pygame program (adapted from the official documentation). It creates a 1000 × 1000 window, clears the screen each frame, and limits the loop to 20 FPS.

import pygame

# initialize pygame
pygame.init()

# create 1000x1000 pixel pygame window
screen = pygame.display.set_mode((1000, 1000))

# clock used to set FPS
clock = pygame.time.Clock()

# game runs as long as this is True
running = True

while running:
    # poll for events
    for event in pygame.event.get():
        # pygame.QUIT = user closed window
        if event.type == pygame.QUIT:
            running = False

    # fill buffer with white
    screen.fill("white")

    # copy buffer to screen
    pygame.display.flip()

    # limits FPS
    clock.tick(20)

pygame.quit()

Note: The running flag is used to exit the loop cleanly when a QUIT event occurs. Python cannot break out of nested loops directly, so this pattern is common in Pygame programs.

Adding a Moving Square

To animate a square, we need a variable that tracks its position. Pygame provides a convenient Vector2 class for 2‑D coordinates.

1. Create a position vector just before the main loop:

   dot = pygame.Vector2(500, 500)

2. Update the position and draw the square inside the loop, after clearing the screen:

   # fill buffer with white
   screen.fill("white")
   
   # move the square
   dot.x += 10
   square = pygame.Rect(dot, (50, 50))
   screen.fill("black", square)

The screen.fill("white") call clears the previous frame, and the three new lines draw a 50 × 50 black square at the updated coordinates.

Full Code with Moving Square

import pygame

# pygame setup
pygame.init()
screen = pygame.display.set_mode((1000, 1000))
clock = pygame.time.Clock()
running = True

# initial position of the square
dot = pygame.Vector2(500, 500)

while running:
    # poll for events
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

    # clear the screen
    screen.fill("white")

    # update position and draw the square
    dot.x += 10
    square = pygame.Rect(dot, (50, 50))
    screen.fill("black", square)

    # present the frame
    pygame.display.flip()

    # limit FPS
    clock.tick(20)

pygame.quit()

Challenge

If you’re comfortable with Python, try extending the program:

• Add a check to see if dot.x exceeds the window width (1000).
• If it does, reset dot.x to 0 so the square reappears on the left side after moving off the right edge.

dot.x += 10
if dot.x > 1000:
    dot.x = 0