main.py

import pygame, sys, time, random 


speed = 10

#window sizes 

frame_size_x = 720 
frame_size_y = 480 

check_errors = pygame.init()

if (check_errors[1] > 0 ):
    print("Error" + check_errors[1 ])
else:
    print('Game Successfully initiialized')

# initialise game windows

pygame.display.set_caption("Snake Game")
game_window = pygame.display.set_mode((frame_size_x,frame_size_y))

# colors 
black = pygame.Color(0,0,0)
white = pygame.Color(255,255,255)
red = pygame.Color(255,0,0)
green = pygame.Color(0,255,0)
blue = pygame.Color(0,0,255)


fps_controller = pygame.time.Clock()

#One snake square size 

square_size = 20 

def init_vars():
    global head_pos, snake_body, food_pos, food_spawn, score, direction
    direction= "RIGHT"
    head_pos = [120,60]
    snake_body = [[120,60]]
    food_pos = [random.randrange(1, (frame_size_x // square_size )) * square_size,
                random.randrange(1, (frame_size_y// square_size)) * square_size] 
    food_spawn = True
    score = 0 

init_vars()

def show_score(choice,color,font,size):
    score_font = pygame.font.SysFont(font,size)
    score_surface = score_font.render("Score: " + str(score), True, color)
    score_rect = score_surface.get_rect()
    if choice == 1:
        score_rect.midtop = (frame_size_x / 10, 15)
    else:
        score_rect.midtop = (frame_size_x / 2, frame_size_y/1.25)

    game_window.blit(score_surface, score_rect)

#Game loop 

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()
        elif event.type == pygame.KEYDOWN:
            if ( event.key == pygame.K_UP or event.key == ord("w") 
                and direction != "DOWN" ):
                direction = "UP"
            elif ( event.key == pygame.K_DOWN or event.key == ord("s") 
                and direction != "UP" ):
                direction = "DOWN"
            elif ( event.key == pygame.K_RIGHT or event.key == ord("d") 
                and direction != "LEFT" ):
                direction = "RIGHT"
            
            elif ( event.key == pygame.K_LEFT or event.key == ord("a") 
                and direction != "RIGHT" ):
                direction = "LEFT"

    if direction == "UP":
        head_pos[1] -= square_size
    elif direction == "DOWN":
        head_pos[1] += square_size
    elif direction == "LEFT":
        head_pos[0] -= square_size
    elif direction == "RIGHT":
        head_pos[0] += square_size








    if head_pos[0] < 0 :
        head_pos[0] = frame_size_x - square_size
    elif head_pos[0] > frame_size_x - square_size:
        head_pos[0] = 0 
    elif head_pos[1] < 0:
        head_pos[1] = frame_size_y - square_size
    elif head_pos[1] > frame_size_y - square_size:
        head_pos[1] = 0 

    # eating apple 

    snake_body.insert(0,list(head_pos))
    if head_pos[0] == food_pos[0] and head_pos[1] == food_pos[1]:
        score += 1 
        food_spawn = False 
    else :
        snake_body.pop()

    # spawn food 
    if not food_spawn:
        food_pos = [random.randrange(1,(frame_size_x // square_size )) * square_size,
           random.randrange(1, (frame_size_y// square_size)) * square_size]
        food_spawn = True

    # GFX 
    game_window.fill(black) 
    for pos in snake_body: 
        pygame.draw.rect(game_window, green, pygame.Rect(
            pos[0] + 2, pos[1] + 2,
            square_size - 2, square_size -2))

    pygame.draw.rect(game_window,red, pygame.Rect(food_pos[0],
                        food_pos[1], square_size,square_size))
    # game over conditions
    for block in snake_body[1:]:
        if head_pos[0]== block[0] and head_pos[1] == block[1]:
            init_vars()
    show_score(1, white,'consolas',20)
    pygame.display.update()
    fps_controller.tick(speed)