def bgscroll(self):
#Handles Background Updating
#Backgrounds are special Obstacle instances with no Collision check
#Background (re)placement, updating, and draw function calling
#is handled here, unlike other Obstacle instances
if ( self.bginit ):
#Initial Background placement, runs only when Game instance starts
sl = random.choice(streetlist)
street1 = Obstacle(sl[0], sl[1], sl[2], sl[3], sl[4])
bg1 = Obstacle(self.bg, -21, False, 1, 0)
house1 = Obstacle(self.house, 0, False, 1.5, 0)
sl = random.choice(streetlist)
street2 = Obstacle(sl[0], sl[1], sl[2], sl[3], sl[4])
bg2 = Obstacle(self.bg, -21, False, 1, 0)
house2 = Obstacle(self.house, 0, False, 1.5, 0)
self.BgGr.add(street1, street2, bg1, bg2, house1, house2)
#Declaring local position variables
street1.xpos = 0
bg1.xpos = 0
house1.xpos = 0
street2.xpos= 1300
bg2.xpos = 1000
house2.xpos = 1000
self.bginit = False
for item in self.BgGr:
#After initial placement, only repositioning and drawing takes place
#Level progress calculation is based on Background instances which
#left the screen
item.update()
if item.xpos <= -(item.rect[2]):
item.xpos = item.rect[2]
self.levelprogress += 1
item.draw(self.gameDisplay)
