im working on a tron game with pygame and i cant figure out how to make my tail that the player's car makes disappear after somany pixels. i want the tail to start shortening itself after like 500 pixels. if you can, can you post the full code edited (im kinda a noob at pygame)

thanks

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

def print_text(font, x, y, text, color=(255,255,255)):
    imgText = font.render(text, True, color)
    screen.blit(imgText, (x,y))
    

#main program begins
pygame.init()
w = 500
h = 500
screen = pygame.display.set_mode((w,h))
pygame.display.set_caption("Tron")
font1 = pygame.font.Font(None, 24)
pygame.mouse.set_visible(False)
white = 255,255,255
red = 220, 50, 50
yellow = 230,230,50
black = 0,0,0



pos_x = 300
pos_y = 460
p1 = [[300],[460]]
poss = pos_y,pos_x
print p1
screen.fill(black)

vel_y = 0.7
path = 8 # 8=up 6=right 4=left 2=down
#repeating loop
while True:
    for event in pygame.event.get():
        #Keydown
        if event.type == KEYDOWN:
            if event.key == K_ESCAPE:
                pygame.quit()
                sys.exit()
            if event.key == K_UP and path != 2:
                path = 8
            if event.key == K_RIGHT and path != 4:
                path = 6                
            if event.key == K_LEFT and path != 6:
                path = 4
            if event.key == K_DOWN and path != 8:
                path = 2
    
    if path == 8:
        pos_y -= 1
    elif path == 6:
        pos_x += 1
    elif path == 4:
        pos_x -= 1
    elif path == 2:
        pos_y += 1
    p1[0].append(pos_x)
    p1[1].append(pos_y)
    if pos_y <= 0 or pos_y >= h or pos_x <= 0 or pos_x >= w:
        pygame.quit()
        sys.exit()

    if len(p1[0]) == 10:
        
    
    pygame.time.delay(10) 
    pos = pos_x,pos_y,10,10
    #print pos
    
    pygame.draw.rect(screen, white, pos, 0)
    
    
    pygame.display.update()

Add the cords to a list each time your tron moves. .pop() after max length is reached

I don't know how to do that could you help me

What is if block after line 64, your code never will run.

What is if block after line 64, your code never will run.

i put that there because i was trying to solve my problem and i forgot to delete it

Is this privite project or home work?

Is this privite project or home work?

Private. Why?

I created a new thread with a different problem.

I coded version of your code, but I do not want to give ready answer for home works.

OK, here it is:

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

def print_text(font, x, y, text, color=(255,255,255)):
    imgText = font.render(text, True, color)
    screen.blit(imgText, (x,y))
    

pygame.init()
w = h = 500
screen = pygame.display.set_mode((w,h))
pygame.display.set_caption("Tron")
font1 = pygame.font.Font(None, 24)
pygame.mouse.set_visible(False)
white = 255, 255, 255
red = 220, 50, 50
yellow = 230, 230, 50
black = 0, 0, 0
screen.fill(black)

pos_x, pos_y = 300, 460
tron_path = []

#vel_y = 0.7 # not used

limit = 100
key = K_UP
change = {K_UP:(0,-1), K_RIGHT:(1,0), K_LEFT:(-1,0), K_DOWN:(0,1)}
opposite = {K_UP: K_DOWN, K_LEFT: K_RIGHT}
opposite.update((b,a) for a,b in opposite.items())

speed = 4
counter = 0
grow, growth_rate = 400, 10

while True:
    pygame.time.delay(speed)
    counter += 1
    # growing by time tail (snake game style)
    if counter > grow:
        counter = 0
        limit += growth_rate
        print 'limit', limit
    for event in pygame.event.get():
        if event.type == KEYDOWN:
            if event.key == K_ESCAPE:
                pygame.quit()
                raise SystemExit('Escaped')
            if event.key in change and key != opposite[event.key]:
                key = event.key
    offset_x, offset_y = change[key]
    pos_x += offset_x
    pos_y += offset_y           
    
    #print pos_x, pos_y
    tron_path.append((pos_x, pos_y))

    if len(tron_path) > limit:
        pygame.draw.rect(screen, black, tron_path.pop(0) + (10, 10), 0)

    if pos_y <= 0 or pos_y >= h or pos_x <= 0 or pos_x >= w:
        pygame.quit()
        raise SystemExit('Out of board exit')

    pos = pos_x, pos_y, 10, 10
    pygame.draw.rect(screen, white, pos, 0)
    pygame.display.update()

Ok thanks. This will help me out a lot