Building a Snake Game using Python and Tkinter: A Step-by-Step Guide

The Snake game involves controlling a snake on a 2D grid and eating food while avoiding collision with walls and the snake’s own body. The game loop runs continuously until the game ends due to collision or player exit. The player can control the snake’s direction using the arrow keys on the keyboard. The game keeps track of the player’s score and displays it on the screen.

import tkinter as tk
import random

class Snake:
    def __init__(self, master):
        self.master = master
        master.title("Snake")

        # Set up the game canvas
        self.canvas = tk.Canvas(master, width=400, height=400, bg='black')
        self.canvas.pack()

        # Create the snake and food
        self.snake = [(200, 200), (190, 200), (180, 200)]
        self.food = self.create_food()

        # Set up the game loop
        self.direction = 'Right'
        self.game_over = False
        self.delay = 500
        self.score = 0
        self.label = tk.Label(master, text=f"Score: {self.score}")
        self.label.pack()

        # Bind arrow keys to change direction
        master.bind('<Up>', lambda event: self.change_direction('Up'))
        master.bind('<Down>', lambda event: self.change_direction('Down'))
        master.bind('<Left>', lambda event: self.change_direction('Left'))
        master.bind('<Right>', lambda event: self.change_direction('Right'))

        # Start the game loop
        self.game_loop()

    def create_food(self):
        # Create a new piece of food at a random location on the canvas
        x = random.randint(0, 19) * 20
        y = random.randint(0, 19) * 20
        food = self.canvas.create_oval(x, y, x+20, y+20, fill='red')
        return food
    def draw_snake(self):
        self.square_size = 20
        self.canvas.delete('snake')

        for i, (x, y) in enumerate(self.snake):
            if i == 0:
                self.canvas.create_rectangle(x, y, x + self.square_size, y + self.square_size,
                                            fill='white', tags='snake')
            else:
                self.canvas.create_rectangle(x, y, x + self.square_size, y + self.square_size,
                                            fill='green', tags='snake')


    def move_snake(self):
        # Move the snake one step in the current direction
        head = self.snake[0]
        if self.direction == 'Up':
            new_head = (head[0], head[1]-20)
        elif self.direction == 'Down':
            new_head = (head[0], head[1]+20)
        elif self.direction == 'Left':
            new_head = (head[0]-20, head[1])
        elif self.direction == 'Right':
            new_head = (head[0]+20, head[1])
        self.snake.insert(0, new_head)
        self.canvas.delete(self.snake[-1])
        self.snake.pop()

    def check_collision(self):
        # Check for collision with the walls or the snake's body
        head = self.snake[0]
        if head[0] < 0 or head[0] >= 400 or head[1] < 0 or head[1] >= 400:
            self.game_over = True
        for segment in self.snake[1:]:
            if head == segment:
                self.game_over = True

    def check_food(self):
        # Check if the snake has eaten the food
        if self.snake[0] == self.canvas.coords(self.food):
            self.canvas.delete(self.food)
            self.food = self.create_food()
            self.score += 10
            self.label.config(text=f"Score: {self.score}")

    def change_direction(self, direction):
        # Change the direction of the snake
        if direction == 'Up' and self.direction != 'Down':
            self.direction = 'Up'
        elif direction == 'Down' and self.direction != 'Up':
            self.direction = 'Down'
        elif direction == 'Left' and self.direction != 'Right':
            self.direction = 'Left'
        elif direction == 'Right' and self.direction != 'Left':
            self.direction = 'Right'

    def game_loop(self):
        # Main game loop
        if not self.game_over:
            self.draw_snake()
            self.move_snake()
            self.check_collision()
            self.check_food()
            if not self.game_over:
                self.master.after(self.delay, self.game_loop)
            else:
                self.canvas.create_text(200, 200, text="Game Over!", fill='white', font=('Helvetica', 30))

# Create the game window
root = tk.Tk()

# Start the game
snake = Snake(root)

# Run the game window
root.mainloop()