Some of the objects in sprite group are getting stuck on screen instead of moving in pygame-CodePudding

import pygame
from sys import exit
import random

WIDTH, HEIGHT = 1400,750
FPS = 60
HEADWAY_GAP = 40
vehicleColor = {0:"red",1:"blue",2:"yellow"}
directions = ["Right", "Left"]
classofVehicle = ["Car","Bike","Bus"]
coord = {"Right":(0,300), "Left":(1400,350)}
objects = {"Right":[],"Left":[]}

pygame.init()
myWindow = pygame.display.set_mode((WIDTH, HEIGHT))
clock = pygame.time.Clock()
road = pygame.image.load("Required_images/Road/Road_final.png")

class Vehicle(pygame.sprite.Sprite):
  def __init__(self, ClassofVehicle, Color_Code, direction, pos):
    super().__init__()
    self.Class = ClassofVehicle
    self.Color_Code = Color_Code
    self.direction = direction
    self.pos = pos
    path = "Required_images/" ClassofVehicle "/" ClassofVehicle "_" Color_Code ".png"
    self.image = pygame.image.load(path)
    self.rect = self.image.get_rect()
    if self.direction == "Right":
      self.rect.midright = pos
    else:
      self.rect.midleft = pos
    self.index = len(objects[direction])-1

  def movingVehicles(self):
    if self.direction == "Right":
      if self.index == 0 or (self.rect.x   self.rect.width < objects[self.direction][self.index].rect.x - HEADWAY_GAP):
        self.rect.x  = 1
    elif self.direction == "Left":
      if self.index == 0 or (self.rect.x - self.rect.width > objects[self.direction][self.index].rect.x   HEADWAY_GAP):
        self.rect.x -= 1
  
  def update(self):
    self.movingVehicles()

Object_timer = pygame.USEREVENT 1
pygame.time.set_timer(Object_timer, 1000)
objectsGroup = pygame.sprite.Group()

def generatingObjects():
  Dir = random.choice(directions)
  po = coord[Dir]
  color_code = random.choice([0,1,2])
  cla = random.choice(classofVehicle)
  object = Vehicle(cla,vehicleColor[color_code],Dir,po)
  objectsGroup.add(object)
  objects[Dir].append(object)

while True:
  for event in pygame.event.get():
    if event.type == pygame.QUIT:
      pygame.quit()
      exit()

    if event.type == Object_timer:
      generatingObjects()


myWindow.fill((0,0,0))
objectsGroup.update()
objectsGroup.draw(myWindow)
pygame.display.update()
clock.tick(FPS)

I have created a sprite class and a sprite group. I also created an user defined event to generate vehicles for every 1000ms. To display the vehicles on the screen instead of looping through all the elements of the sprite group separately I used group_name.draw() method. But when I run the code, some of the images are getting stuck on the screen for some time and are moving after sometime. I tried to look for any error in the logic but I couldn't find it. If you have any knowledge or able to find the error, please help and also any kind of suggestions are appreciated.

CodePudding user response：

It is a matter of Indentation. You have to draw the scene in the application loop instead of after the application loop:

while True:
  for event in pygame.event.get():
    if event.type == pygame.QUIT:
      pygame.quit()
      exit()

    if event.type == Object_timer:
      generatingObjects()

# INDENTATION
#->|

  myWindow.fill((0,0,0))
  objectsGroup.update()
  objectsGroup.draw(myWindow)
  pygame.display.update()
  clock.tick(FPS)

CodePudding user response：

make sure to indent the elements in your while loop and use a pygame.display.flip() at the very end of your loop.

so it looks like

while True:
  for event in pygame.event.get():
    if event.type == pygame.QUIT:
      pygame.quit()
      exit()

    if event.type == Object_timer:
      generatingObjects()

    myWindow.fill((0,0,0))
    objectsGroup.update()
    objectsGroup.draw(myWindow)
    clock.tick(FPS)
    pygame.display.flip()