parallax-scrolling

Attribution

This code example is taken from Wireframe #3 Source Code: Moon Patrol's illusion of depth, pages 32-33. The code example and related images were created by Rik Cross.

Licensed under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported.

Original Python code

# set screen width and height
WIDTH = 800
HEIGHT = 400

# create the back layer
layer_back = Actor('image_back')
layer_back.topleft = 0, 0
layer_back.speed = 1

#create the middle layer
layer_middle = Actor('image_middle')
layer_middle.topleft = 0, 0
layer_middle.speed = 3

#create the front layer
layer_front = Actor('image_front')
layer_front.topleft = 0, 0
layer_front.speed = 5

#add layers to list
layers = [layer_back, layer_middle, layer_front]

def update():
    for l in layers:
        # move each layer to the left
        l.left -= l.speed
        # if the layer has moved far enough to the left
        # then reset the layers position
        if l.right <= WIDTH:
            l.left = 0

def draw():
    screen.clear()
    # draw all images in the image list
    for l in layers:
        l.draw()