pygame_5.py

import pygame
import random
#Initialize pygame
pygame.init()
# Set the screen size of our game
screen_width = 800
screen_height = 600
screen = pygame.display.set_mode((screen_width, screen_height))
#Main Event loop
done = False
#Game loop
game_over = False
# Variable to store all the snake rectangles
green=(76, 235, 52)
red=(255, 0, 0)
#List of all snake rectangles
snake_segments = [pygame.Rect(40, 40, 20, 20)]
#Generate the Apple rectangle random
apple = pygame.Rect(random.randint(0, screen_width/20) *20,
                    random.randint(0, screen_height/20) *20, 20, 20)
#generate start version of the snake
for x in range(9):
    #Copy the last item and add the y-axis/top value +20
    y = snake_segments[-1].y
    y += 20
    snake_segments.append(pygame.Rect(40, y, 20, 20))

#Start Speed
x_change = 20
y_change = 0

#pygame clock to control the refresh rate of our game
clock = pygame.time.Clock()

while not done:
    #Set the backgroudn color to black
    screen.fill((0, 0, 0))
    #Close the game if someone clicks the X top right
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            done = True
    if not game_over:
        
        #Keyboard input arrow keys
        pressed = pygame.key.get_pressed()

        if pressed[pygame.K_UP]:
            x_change = 0
            y_change = -20
        if pressed[pygame.K_DOWN]:
            x_change = 0
            y_change = 20
        if pressed[pygame.K_LEFT]:
            x_change = -20
            y_change = 0
        if pressed[pygame.K_RIGHT]:
            x_change = 20
            y_change = 0
            

        x = snake_segments[0].x + x_change
        y = snake_segments[0].y + y_change
        #Check if the snake is not out of the screen if so Game Over.
        if(x > screen_width or x < 0 or y > screen_height or y < 0):
            game_over = True
        #Check if the snake runs into istelf if so = Game Over
        if snake_segments[0].collidelistall(snake_segments) != [0]:
            game_over = True    
        #Remove the last element so the snake will move and remains the same lenght 
        snake_segments.pop()   
        #Append the moved part a the new position
        snake_segments.insert(0, pygame.Rect(x, y, 20, 20))

        #Draw all parts of the snake
        for segment in snake_segments:
            pygame.draw.rect(screen, green, segment)
        # draw the apple
        pygame.draw.rect(screen, red, apple)

        pygame.display.flip()
        #Define the frame rate = how many times per second the screen schould refresh and the snake move
        clock.tick(5)