arrow22
Posts: 2
Joined: Thu Jan 02, 2020 10:36 pm

Raspberry Snake in Python 2--Game not working, Unknown Error

Thu Jan 02, 2020 10:46 pm

I recently got a Raspberry Pi 3B+ and I've been using the Raspberry Pi User Guide by Eben Upton to get started. One of the activities that I did was creating Raspberry Snake with Python 2. There were a couple errors that I took care of, but when I ran the program, the only direction that I could go was up!
After the GAME OVER message went away, an error popped up in the Shell window:
Traceback (most recent call last):
File "/home/pi/raspberrySnake.py", line 36, in <module>
for event in pygame.event.get():
pygame.error: video system not initialized
I went to line 36 but couldn't see my error.

Could someone please explain what "pygame.error: video system not initialized" means? I'm new to Python and haven't seen this kind of error before.
Thank you!

User avatar
paddyg
Posts: 2463
Joined: Sat Jan 28, 2012 11:57 am
Location: UK

Re: Raspberry Snake in Python 2--Game not working, Unknown Error

Sat Jan 04, 2020 1:48 pm

As of last Tuesday night python2 has reached end of life, so unless you have a burning need to use it I would suggest switching to python3. I don't have the exact code you're using but I found an approximation to the listing below elsewhere on this forum and it seems to work on this laptop with python3.

Code: Select all

#!/user/bin/env python

import pygame, sys, time, random
from pygame.locals import *

pygame.init()
fpsClock = pygame.time.Clock()

playSurface = pygame.display.set_mode((640, 480))
pygame.display.set_caption('Raspberry Snake')

redColour = pygame.Color(255, 0, 0)
blackColour = pygame.Color(0, 0, 0)
whiteColour = pygame.Color(255, 255, 255)
greyColour = pygame.Color(150, 150, 150)
snakePosition = [100,100]
snakeSegments = [[100,100],[80,100],[60,100]]
raspberryPosition = [300,300]
raspberrySpawned = 1
direction = 'right'
changeDirection = direction

def gameOver():
    gameOverFont = pygame.font.font('freesansbold.ttf', 72)
    gameOverSurf = gameOverFont.render('Game Over', True, greyColour)
    gameOverRect = gameOverSurf.get_rect()
    gameOverRect.midtop = (320, 10)
    playSurface.blit(gameOverSurf, gameOverRect)
    pygame.display.flip()
    time.sleep(5)
    pygame.quit()
    sys.exit()

while True:
    for event in pygame.event.get():
        if event.type == QUIT:
            pygame.quit()
            sys.exit()
        elif event.type == KEYDOWN:
            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))
    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
    snakeSegments.insert(0,list(snakePosition))
    if snakePosition[0] == raspberryPosition[0] and snakePosition[1] == raspberryPosition[1]:
        raspberrySpawned = 0
    else:
        snakeSegments.pop()
    if raspberrySpawned == 0:
        x = random.randrange(1,32)
        y = random.randrange(1,24)
        raspberryPosition = [int(x*20),int(y*20)]
    raspberrySpawned = 1
    playSurface.fill(blackColour)
    for position in snakeSegments:
        pygame.draw.rect(playSurface,whiteColour,Rect(position[0], position[1], 20, 20))

    pygame.draw.rect (playSurface,redColour,Rect(raspberryPosition[0], raspberryPosition[1], 20, 20))
    pygame.display.flip()
    if snakePosition[0] > 620 or snakePosition[0] < 0:
        gameOver()
    if snakePosition[1] > 460 or snakePosition[1] < 0:
        gameOver()
    for snakeBody in snakeSegments[1:]:
        if snakePosition[0] == snakeBody[0] and snakePosition[1] == snakeBody[1]:
            gameover()

    fpsClock.tick(30)
also https://groups.google.com/forum/?hl=en-GB&fromgroups=#!forum/pi3d


User avatar
joelostinspace
Posts: 51
Joined: Sat Aug 10, 2019 2:51 pm
Location: Earth

Re: Raspberry Snake in Python 2--Game not working, Unknown Error

Sat Jan 04, 2020 9:53 pm

one small typo:
def gameOver():
gameOverFont = pygame.font.font('freesansbold.ttf', 72)
to:

Code: Select all

def gameOver():
    gameOverFont = pygame.font.Font('freesansbold.ttf', 72)

I would rather live in a world where my life is surrounded by mystery than a world so small that my mind could comprehend it.


--- Harry Emerson Fosdick

arrow22
Posts: 2
Joined: Thu Jan 02, 2020 10:36 pm

Re: Raspberry Snake in Python 2--Game not working, Unknown Error

Tue Jan 07, 2020 9:48 pm

Ahhh. Thanks so much!

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