Welcome folks today in this blog post we will be building a 2d snake game in tkinter using pygamelibrary. All the full source code of the application is shown below.

Get Started

In order to get started you need to install the following libraries using the pip command as shown below

pip install pygame

After installing this library you need to make an app.py file and copy paste the following code

app.py

import math
import random
import pygame
import random
import tkinter as tk
from tkinter import messagebox

width = 500
height = 500

cols = 25
rows = 20


class cube():
    rows = 20
    w = 500
    def __init__(self, start, dirnx=1, dirny=0, color=(255,0,0)):
        self.pos = start
        self.dirnx = dirnx
        self.dirny = dirny # "L", "R", "U", "D"
        self.color = color

    def move(self, dirnx, dirny):
        self.dirnx = dirnx
        self.dirny = dirny
        self.pos  = (self.pos[0] + self.dirnx, self.pos[1] + self.dirny)
            

    def draw(self, surface, eyes=False):
        dis = self.w // self.rows
        i = self.pos[0]
        j = self.pos[1]
        
        pygame.draw.rect(surface, self.color, (i*dis+1,j*dis+1,dis-2,dis-2))
        if eyes:
            centre = dis//2
            radius = 3
            circleMiddle = (i*dis+centre-radius,j*dis+8)
            circleMiddle2 = (i*dis + dis -radius*2, j*dis+8)
            pygame.draw.circle(surface, (0,0,0), circleMiddle, radius)
            pygame.draw.circle(surface, (0,0,0), circleMiddle2, radius)
        


class snake():
    body = []
    turns = {}
    
    def __init__(self, color, pos):
        #pos is given as coordinates on the grid ex (1,5)
        self.color = color
        self.head = cube(pos)
        self.body.append(self.head)
        self.dirnx = 0
        self.dirny = 1
    
    def move(self):
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
            keys = pygame.key.get_pressed()

            for key in keys:
                if keys[pygame.K_LEFT]:
                    self.dirnx = -1
                    self.dirny = 0
                    self.turns[self.head.pos[:]] = [self.dirnx,self.dirny]
                elif keys[pygame.K_RIGHT]:
                    self.dirnx = 1
                    self.dirny = 0
                    self.turns[self.head.pos[:]] = [self.dirnx,self.dirny]
                elif keys[pygame.K_UP]:
                    self.dirny = -1
                    self.dirnx = 0
                    self.turns[self.head.pos[:]] = [self.dirnx,self.dirny]
                elif keys[pygame.K_DOWN]:
                    self.dirny = 1
                    self.dirnx = 0
                    self.turns[self.head.pos[:]] = [self.dirnx,self.dirny]
        
        for i, c in enumerate(self.body):
            p = c.pos[:]
            if p in self.turns:
                turn = self.turns[p]
                c.move(turn[0], turn[1])
                if i == len(self.body)-1:
                    self.turns.pop(p)
            else:
                c.move(c.dirnx,c.dirny)
        
        
    def reset(self,pos):
        self.head = cube(pos)
        self.body = []
        self.body.append(self.head)
        self.turns = {}
        self.dirnx = 0
        self.dirny = 1

    def addCube(self):
        tail = self.body[-1]
        dx, dy = tail.dirnx, tail.dirny

        if dx == 1 and dy == 0:
            self.body.append(cube((tail.pos[0]-1,tail.pos[1])))
        elif dx == -1 and dy == 0:
            self.body.append(cube((tail.pos[0]+1,tail.pos[1])))
        elif dx == 0 and dy == 1:
            self.body.append(cube((tail.pos[0],tail.pos[1]-1)))
        elif dx == 0 and dy == -1:
            self.body.append(cube((tail.pos[0],tail.pos[1]+1)))

        self.body[-1].dirnx = dx
        self.body[-1].dirny = dy
    
    def draw(self, surface):
        for i,c in enumerate(self.body):
            if i == 0:
                c.draw(surface, True)
            else:
                c.draw(surface)



def redrawWindow():
    global win
    win.fill((0,0,0))
    drawGrid(width, rows, win)
    s.draw(win)
    snack.draw(win)
    pygame.display.update()
    pass



def drawGrid(w, rows, surface):
    sizeBtwn = w // rows

    x = 0
    y = 0
    for l in range(rows):
        x = x + sizeBtwn
        y = y +sizeBtwn

        pygame.draw.line(surface, (255,255,255), (x, 0),(x,w))
        pygame.draw.line(surface, (255,255,255), (0, y),(w,y))
    


def randomSnack(rows, item):
    positions = item.body

    while True:
        x = random.randrange(1,rows-1)
        y = random.randrange(1,rows-1)
        if len(list(filter(lambda z:z.pos == (x,y), positions))) > 0:
               continue
        else:
               break

    return (x,y)


def main():
    global s, snack, win
    win = pygame.display.set_mode((width,height))
    s = snake((255,0,0), (10,10))
    s.addCube()
    snack = cube(randomSnack(rows,s), color=(0,255,0))
    flag = True
    clock = pygame.time.Clock()
    
    while flag:
        pygame.time.delay(50)
        clock.tick(10)
        s.move()
        headPos = s.head.pos
        if headPos[0] >= 20 or headPos[0] < 0 or headPos[1] >= 20 or headPos[1] < 0:
            print("Score:", len(s.body))
            s.reset((10, 10))

        if s.body[0].pos == snack.pos:
            s.addCube()
            snack = cube(randomSnack(rows,s), color=(0,255,0))
            
        for x in range(len(s.body)):
            if s.body[x].pos in list(map(lambda z:z.pos,s.body[x+1:])):
                print("Score:", len(s.body))
                s.reset((10,10))
                break
                    
        redrawWindow()

main()

Now if you execute the python script by typing the below command as shown below

python app.py