snake in python using the pygame module

Question

Alright so running the code draws the snake, but I can't move it at all. Trying to make it so that the snake doesn't stop when it starts moving. I'm new to programming in general so sorry if I'm dumb, but for the love of god I can't figure out how to make this work, please help. The grid function works just fine, but the move functions don't at all.

Here's the code

# Snake game

import pygame


pygame.init()
pygame.display.set_caption("Snake Game and AI")

WIDTH = 24
HEIGHT = 24
SCREEN = pygame.display.set_mode((500, 500))
RED = (255, 0, 0)
BLACK = (0, 0, 0)
GREEN = (0, 128, 0)
WHITE = (255, 255, 255)
SPEED = 25
x_head = 251
y_head = 251
keys = pygame.key.get_pressed()
direction = None


def grid():
    for x in range(25, 500, 25):
        pygame.draw.rect(SCREEN, WHITE, (x, 25, 1, 450))

    for y in range(25, 500, 25):
        pygame.draw.rect(SCREEN, WHITE, (25, y, 450, 1))


def press_key():
    global direction
    global keys
    if keys[pygame.K_RIGHT] and direction != 'left':
        direction = 'right'
    if keys[pygame.K_LEFT] and direction != 'right':
        direction = 'left'
    if keys[pygame.K_UP] and direction != 'down':
        direction = 'up'
    if keys[pygame.K_DOWN] and direction != 'up':
        direction = 'down'


def move_snake():
    global x_head
    global y_head
    global SCREEN
    global WIDTH
    global HEIGHT
    while direction == 'right':
        x_head += SPEED
    while direction == 'left':
        x_head -= SPEED
    while direction == 'up':
        y_head -= SPEED
    while direction == 'down':
        y_head += SPEED

    pygame.draw.rect(SCREEN, GREEN, (x_head, y_head, WIDTH, HEIGHT))


is_running = True
while is_running:
    pygame.time.delay(150)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            is_running = False

    press_key()
    SCREEN.fill(BLACK)
    grid()
    move_snake()
    pygame.display.update()


pygame.quit()

In `move_snake()` you probably want `if direction ==` rather than `while direction ==`, since this will cause an infinite loop. — Kingsley, Jan 27 '20 at 22:14

Rabbid76 · Accepted Answer · 2020-01-27T22:16:55.407

pygame.key.get_pressed() returns a list of states of every key on the keyboard. You have to retrieve the current states of the keys in every frame:

is_running = True
while is_running:
    pygame.time.delay(150)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            is_running = False

    # get current key states
    keys = pygame.key.get_pressed() # <-----

    press_key()
    # [...]

Furthermore, move_snake is called int he main application loop. You don't need the endless loops in move_snake at all. Change the while loops to a selection (if). The snake does one step in every frame, dependent on the state of direction:

def move_snake():
    global x_head
    global y_head
    global SCREEN
    global WIDTH
    global HEIGHT
    if direction == 'right':
        x_head += SPEED
    if direction == 'left':
        x_head -= SPEED
    if direction == 'up':
        y_head -= SPEED
    if direction == 'down':
        y_head += SPEED

snake in python using the pygame module

1 Answers1