class BackgroundManager(pygame.sprite.Sprite):
	stars=[ ]
	last_stars=[ ]
	
	def __init__(self):
		for x in range(init_stars):
			self.add_star()
	
	def update(self):
		counter=0
		for star in self.stars:
			if star.top > WIN_RESY:
				del self.last_stars[counter]
			else:
				self.last_stars[counter]=pygame.Rect(star.topleft,(star.width+2, star.height+2))
			counter+=1
		
		counter=0
		for star in self.stars:
			if star.top > WIN_RESY:
				del self.stars[counter]
				#del self.last_stars[counter]
				self.add_star()
			else:
				#self.last_stars[counter]=pygame.Rect(star.topleft,(star.width+2, star.height+2))
				star.move_ip(0,star.get_speed())
			counter+=1
		
	
	def draw(self):
		for star in self.stars:
			surface.fill((255,255,255),star)
		return self.stars
		
	def clear(self):
		for star in self.last_stars:
			surface.fill((0,0,0),star)
			
	def add_star(self):
		size=random.randint(3,6)
		x=random.randint(0,WIN_RESX)
		rect=star(x,0,size,size)
		rect.set_speed(random.randint(8,BG_Speed))
		self.stars.append(rect)
		self.last_stars.append(rect)