Apple won't disappear when my snake is touching it

Question

This is my first post! I am trying to make a snake clone in Pygame, but when my snake touches the apple, it won't teleport to another place. Here's my code:

import pygame          
import time
import random

pygame.init()          

wh = (255,255,255)     #white
bk = (0,0,0)           #black
ylw = (255,255,0)      #yellow 
prpl = (127,0,127)     #purple

snakeXChange = 0
snakeYChange = 0
dWidth = 800
dHeight = 600 
clock = pygame.time.Clock()
fps = 25
blockSize = 15
appleX = round(random.randrange(0, dWidth - blockSize)/ 10.0)* 10.0
appleY = round(random.randrange(0, dHeight - blockSize) / 10.0)* 10.0
snakeX = dWidth / 2           
snakeY = dHeight / 2          
font = pygame.font.SysFont(None, 25)
def message(msg, color):
    screenText = font.render(msg, True, color)
    gameDisplay.blit(screenText, [dWidth / 2, dHeight / 2])

gameDisplay = pygame.display.set_mode((dWidth,dHeight))     
pygame.display.set_caption('Snek')                   #shoutout to Hopson


gameExit = False                                    
gameOver = False


while not gameExit:                                  
    for event in pygame.event.get():                 
        if event.type == pygame.QUIT:                
            gameExit = True                         
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_LEFT:
                snakeXChange = -blockSize
                snakeYChange = 0
            if event.key == pygame.K_RIGHT:
                snakeXChange = blockSize
                snakeYChange = 0
            if event.key == pygame.K_UP:
                snakeYChange = -blockSize
                snakeXChange = 0
            if event.key == pygame.K_DOWN:
                snakeYChange = blockSize
                snakeXChange = 0


    snakeX += snakeXChange

    snakeY += snakeYChange

    gameDisplay.fill(prpl)                          

    pygame.draw.rect(gameDisplay, wh, [snakeX,snakeY,blockSize,blockSize])  #snake

    pygame.draw.rect(gameDisplay, ylw, [appleX,appleY,blockSize,blockSize]) #apple

    if snakeX == appleX and snakeY == appleY:
        appleX = round(random.randrange(0, dWidth - blockSize)/ 10.0)* 10.0
        appleY = round(random.randrange(0, dHeight - blockSize) / 10.0)* 10.0

    clock.tick(fps)

    pygame.display.update()  

message("GAME OVER NIBBA", ylw)
pygame.display.update()                              #updates the display
time.sleep(5)
pygame.quit()                                        
quit()

Original source: https://paste.ee/p/eSimt

I am following theNewBoston's tutorials as a reference.

Cheers

SalmonSan

Just to be clear, you want the apple to teleport / move to new location right? Also, from a quick glance, it seems your apple coordinates are float, but snake's are int. Now that may be a reason why the "teleport" doesn't happen because your condition for teleport (`if apple == snake`) may not be getting triggered. Try putting some print statements to output the location of the apple & the snake in the loop, that'll help you debug the cause. Good luck. — shad0w_wa1k3r, Sep 02 '18 at 07:52

score 3 · Answer 1 · answered Sep 02 '18 at 09:34

You're rounding the appleX and appleY coordinates to the nearest multiple of 10, but move in steps of 15 px, and that means it can happen that the snake isn't able to touch the apple. For example the appleX could be 410 and the snake starts at 400, so it would never be able to reach the apple.

Just round all positions to the nearest multiple of 15 (the blockSize and speed):

appleX = round(random.randrange(0, dWidth - blockSize) / 15.0) * 15.0
appleY = round(random.randrange(0, dHeight - blockSize) / 15.0) * 15.0
snakeX = round(dWidth / 2. / 15.) * 15
snakeY = round(dHeight / 2. / 15.) * 15

You could also just pass 15 as the step argument to random.randrange to get a random multiple of 15.

appleX = random.randrange(0, dWidth-blockSize, 15)

It would also be possible to use pygame.Rects for the collision detection and to store the coordinates.

Just nitpicking a bit, but the snake could actually touch the apple (meaning the two rectangles might have an intersection) and the apple still wouldn't "teleport" because snakeX != appleX (or Y). In the OP code I mean. — ChatterOne, Sep 03 '18 at 10:08

Apple won't disappear when my snake is touching it

1 Answers1