Raspberry Pi Guia Del Usuario página 161

if event.key == K_RIGHT or event.key == ord('d'):
changeDirection = 'right'
if event.key == K_LEFT or event.key == ord('a'):
changeDirection = 'left'
if event.key == K_UP or event.key == ord('w'):
changeDirection = 'up'
if event.key == K_DOWN or event.key == ord('s'):
changeDirection = 'down'
if event.key == K_ESCAPE:
pygame.event.post(pygame.event.Event(QUIT))
direction
if changeDirection == 'right' and not direction == 'left':
direction = changeDirection
if changeDirection == 'left' and not direction == 'right':
direction = changeDirection
if changeDirection == 'up' and not direction == 'down':
direction = changeDirection
if changeDirection == 'down' and not direction == 'up':
direction = changeDirection
if direction == 'right':
snakePosition[0] += 20
if direction == 'left':
snakePosition[0] -= 20
if direction == 'up':
snakePosition[1] -= 20
if direction == 'down':
snakePosition[1] += 20
+= -=
changeDirection
W A S D
changeDirection
changeDirection
direction
-=
snakePosition[0] += 20
changeDirection
+=