Build a Fun ‘Eat Coins’ Game with Python & Pygame: OOP Tutorial

After completing several object‑oriented (OOP) mini‑games, this article introduces a light‑hearted yet educational game called "Eat Coins". The player controls a character that moves around the screen, collects randomly appearing coins, and earns points, demonstrating how OOP integrates with Pygame.

🗂️ Directory

Project Overview and Goals

OOP Design Analysis

Creating the Player class (Player)

Creating the Coin class (Coin)

Game Management class (Game)

Game Loop and Event Handling

Collision Detection and Scoring System

Beautification and Optimization Suggestions

Project Summary and Extension Exercises

1. Project Overview and Goals

Goals:

Player controls character movement

Collect as many coins as possible within a time limit

Earn points for each collected coin

Coins appear at random positions at intervals

Technical points:

Use Pygame for drawing and handling keyboard events

Encapsulate character and coin logic with OOP

Use the time module to control coin refresh

2. OOP Design Analysis

We will use the following classes to organize the code:

Player

: controls player movement and rendering

Coin

: represents a coin, holds its position and drawing ability

Game

: manages the main loop, object updates and interactions

3. Creating the Player class (Player)

class Player:
    def __init__(self, x, y):
        self.rect = pygame.Rect(x, y, 40, 40)
        self.color = (0, 100, 255)
        self.speed = 5

    def move(self, keys):
        if keys[pygame.K_LEFT]:
            self.rect.x -= self.speed
        if keys[pygame.K_RIGHT]:
            self.rect.x += self.speed
        if keys[pygame.K_UP]:
            self.rect.y -= self.speed
        if keys[pygame.K_DOWN]:
            self.rect.y += self.speed

    def draw(self, window):
        pygame.draw.rect(window, self.color, self.rect)

4. Creating the Coin class (Coin)

import random

class Coin:
    def __init__(self, width, height):
        size = 20
        x = random.randint(0, width - size)
        y = random.randint(0, height - size)
        self.rect = pygame.Rect(x, y, size, size)
        self.color = (255, 215, 0)

    def draw(self, window):
        pygame.draw.ellipse(window, self.color, self.rect)

5. Game Management class (Game)

class Game:
    def __init__(self):
        pygame.init()
        self.width, self.height = 600, 400
        self.window = pygame.display.set_mode((self.width, self.height))
        pygame.display.set_caption("吃金币小游戏")
        self.clock = pygame.time.Clock()
        self.font = pygame.font.SysFont(None, 36)
        self.player = Player(280, 180)
        self.coin = Coin(self.width, self.height)
        self.score = 0
        self.running = True

6. Game Loop and Event Handling

def run(self):
    while self.running:
        self.clock.tick(60)
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                self.running = False
        keys = pygame.key.get_pressed()
        self.player.move(keys)
        self.check_collision()
        self.draw()

7. Collision Detection and Scoring System

def check_collision(self):
    if self.player.rect.colliderect(self.coin.rect):
        self.score += 1
        self.coin = Coin(self.width, self.height)

def draw(self):
    self.window.fill((240, 240, 240))
    self.player.draw(self.window)
    self.coin.draw(self.window)
    text = self.font.render(f"Score: {self.score}", True, (0, 0, 0))
    self.window.blit(text, (10, 10))
    pygame.display.update()

8. Beautification and Optimization Suggestions

Use

pygame.image.load()

to load images for coins or the player

Add a timed challenge (e.g., a 60‑second countdown)

Include background music or a coin‑collection sound effect

Spawn multiple coins simultaneously

9. Project Summary and Extension Exercises

🎉 You have successfully completed an OOP‑based mini‑game project! You learned how to:

Design classes to encapsulate game objects

Manage the game loop and interactions

Implement simple collision detection

Further practice ideas:

Coins with different point values

Add obstacles to avoid collisions

Implement a leaderboard to store high scores

Continue developing your own creative games with Python and Pygame! 🚀