Error when I press C to reload/re-execute code?

Question

I am trying to make a snake game using TheNewBoston's tutorials, since I am a Middle School student and dont have much experience in python. The code is:

__author__ = 'Ded'

import pygame
import time

pygame.init()

display_width = 800
display_height = 600


gameDisplay = pygame.display.set_mode((display_width, display_height))

pygame.display.set_caption('Dipshit')

white = (255, 255, 255)
black = (0, 0, 0)
red = (255, 0, 0)
green = (0, 255, 0)
blue = (0, 0, 255)

clock = pygame.time.Clock()

block_size = 10
FPS = 30

font = pygame.font.SysFont(None, 25)

def message_to_screen(msg,color):
    screen_text = font.render(msg, True, color)
    gameDisplay.blit(screen_text, [display_width/2, display_height/2])


def gameLoop():
    gameExit = False
    gameOver = False

    lead_x = display_width/2
    lead_y = display_height/2
    lead_x_change = 0
    lead_y_change = 0

    while not gameExit:

        while gameOver == True:
            gameDisplay.fill(white)
            message_to_screen("Game over, press C to play again or Q to quit", red)
            pygame.display.update()

            for event in pygame.event.get():
                if event.type == pygame.KEYDOWN:
                    if event.key == pygame.K_q:
                        gameExit = True
                        gameOver = False
                    if event.key == pygame.K_c:
                        gameLoop()

        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                gameExit = True
            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_LEFT:
                    lead_x_change -= block_size
                    lead_y_change = 0
                if event.key == pygame.K_RIGHT:
                    lead_x_change += block_size
                    lead_y_change = 0
                if event.key == pygame.K_DOWN:
                    lead_y_change += block_size
                    lead_x_change = 0
                if event.key == pygame.K_UP:
                    lead_y_change -= block_size
                    lead_x_change = 0


        if event.type == pygame.KEYUP:
            if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT:
                lead_x_change = 0

        if event.type == pygame.KEYUP:
            if event.key == pygame.K_DOWN or event.key == pygame.K_UP:
                lead_y_change = 0

        if lead_x >= display_width or lead_x < 0 or lead_y >= display_height or lead_y < 0:
            gameOver = True

        lead_x += lead_x_change
        lead_y += lead_y_change

        gameDisplay.fill(white)
        pygame.draw.rect(gameDisplay, black, [lead_x,lead_y,block_size,block_size])


        pygame.display.update()

        clock.tick(FPS)
    pygame.quit()
    quit()

gameLoop()

However, I get this error when I execute, play, lose and press C to retry. Q works fine when I want to quit but C just quits, and prints this error:

C:\Python34\python.exe "C:/Users/Ded/PycharmProjects/PyGame/PyGame Tutorial.py" Traceback (most recent call last): File "C:/Users/Ded/PycharmProjects/PyGame/PyGame Tutorial.py", line 100, in gameLoop() File "C:/Users/Ded/PycharmProjects/PyGame/PyGame Tutorial.py", line 56, in gameLoop gameLoop() File "C:/Users/Ded/PycharmProjects/PyGame/PyGame Tutorial.py", line 76, in gameLoop if event.type == pygame.KEYUP: UnboundLocalError: local variable 'event' referenced before assignment

Process finished with exit code 1

I think you want to indent your two if event.type == pygame.KEYUP: blocks in the for even in pygame.event.get() loop. — TidB

rlms rlms · Accepted Answer · 2015-02-15T17:12:11

You need to indent these parts of the code:

    if event.type == pygame.KEYUP:
        if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT:
            lead_x_change = 0

    if event.type == pygame.KEYUP:
        if event.key == pygame.K_DOWN or event.key == pygame.K_UP:
            lead_y_change = 0

so that they are part of the for loop. Otherwise if there are no events to get and no iterations of the loop occur, the variable event won't be defined.

Error when I press C to reload/re-execute code?

1 Answers