Step by Step

Lesson 20 of 40 in Coddy's Make Games with Pygame course.

The snake always moves. Keep the way it is going in a direction: how many cells to add to the column and to the row in each step.

(1, 0) is right, (-1, 0) is left.
(0, 1) is down, (0, -1) is up.

direction = (1, 0)

while running:
    # events
    head = (head[0] + direction[0], head[1] + direction[1])

A tuple cannot be changed, so each step makes a new one. The clock runs at clock.tick(10): ten frames a second, so the snake moves ten cells a second.

Challenge

Easy

Before the loop, set direction = (1, 0).
In the loop, after the events, move the head one step in direction.

The snake leaves the window for now. Walls come later.

Try it yourself

import pygame

CELL = 20
COLS, ROWS = 24, 18

pygame.init()
screen = pygame.display.set_mode((COLS * CELL, ROWS * CELL))
pygame.display.set_caption("Snake")
clock = pygame.time.Clock()


def draw_cell(cell, color):
    col, row = cell
    pygame.draw.rect(screen, color, (col * CELL + 1, row * CELL + 1, CELL - 2, CELL - 2))


head = (5, 9)

running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False


    screen.fill((30, 30, 46))
    draw_cell(head, (180, 255, 160))
    pygame.display.flip()
    clock.tick(10)

pygame.quit()