Pygame restart function

Question

I am doing a game where you control a snake and when he dies the game quits. I have tried adding a different function (on) so only while on is true the game will continue. However, this does not restart here is the code I have and could anyone put in a restart function?

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('Happy Birthday Mum')

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
diff = 30

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()
        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 event.key == K_1:
                diff = 10
            if event.key == K_2:
                diff = 20
            if event.key == K_3:
                diff = 30
            if event.key == K_4:
                diff = 40
            if event.key == K_5:
                diff = 50
            if event.key == K_r:
                restart()

    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(diff)

Answer 1

You essentially want two while loops - one for when the overall game is running, and a smaller one while the snake is alive.

start pygame and set global variables;
while the program is running:
    set all of the initial variables for the game (snake position, etc)
    while the snake is alive:
        handle input;
        check to see if the snake is dead;

I've taken your python code and structured it this way. Pay attention to where I set the variable snake_is_alive to false. See how it makes the inner loop end, but makes the outer loop start over.

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('Happy Birthday Mum')
redColour = pygame.Color(255, 0, 0)
blackColour = pygame.Color(0, 0, 0)
whiteColour = pygame.Color(255, 255, 255)
greyColour = pygame.Color(150, 150, 150)

game_is_running = True
while game_is_running:
        snakePosition = [100,100]
        snakeSegments = [[100,100],[80,100],[60,100]]
        raspberryPosition = [300,300]
        raspberrySpawned = 1
        direction = 'right'
        changeDirection = direction
        diff = 30

        snake_is_alive = True
        while snake_is_alive:
            for event in pygame.event.get():
                if event.type == QUIT:
                    pygame.quit()
                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 event.key == K_1:
                        diff = 10
                    if event.key == K_2:
                        diff = 20
                    if event.key == K_3:
                        diff = 30
                    if event.key == K_4:
                        diff = 40
                    if event.key == K_5:
                        diff = 50
                    if event.key == K_r:
                        snake_is_alive = False

            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:
                snake_is_alive = False
            if snakePosition[1] > 460 or snakePosition[1] < 0:
                snake_is_alive = False
            for snakeBody in snakeSegments[1:]:
                if snakePosition[0] == snakeBody[0] and snakePosition[1] == snakeBody[1]:
                    snake_is_alive = False
            fpsClock.tick(diff)


        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)

I got rid of the functions to make it easier to read, but even if you make functions, the overall structure (inner loop and outer loop) should remain the same.

Answer 2

You need to turn your game into a function just like you did with end game. Then in your end game loop instead of exiting just call playGame again. Make sure that you reset all your variables to there original state at the begging of the loop before the while. Something like this: (pseudo code)

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('Happy Birthday Mum')

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
diff = 30

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)
    playGame();

def playGame():

    RESET ALL GAME VARIABLES HERE

    while True:
        for event in pygame.event.get():
            if event.type == QUIT:
                pygame.quit()
            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 event.key == K_1:
                    diff = 10
                if event.key == K_2:
                    diff = 20
                if event.key == K_3:
                    diff = 30
                if event.key == K_4:
                    diff = 40
                if event.key == K_5:
                    diff = 50
                if event.key == K_r:
                    restart()

        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(diff)


playGame();