Sprite.js documentation — sprite.js 1.2.0 documentation: "Extra Features
To use some of these feature, you must include an extra javascript files in your web page.
ScrollingSurface object
This object is not included in sprite.js core and needs to be loaded independantly:
This object provide a simple and efficent way to display a moving background within a scene. The object buffers parts that have already been drawn and only redraw the necessary parts instead of the whole scene at every frame."
'via Blog this'
