Base class for Verge3D preloaders.
Does nothing, should be overridden in the subclass.
A callback which should be called when the preloader is considered to be off.
A callback which should be continuously called during the loading
process. The percentage parameter varies from 0
(0%) to 1
(100%).
There is a built-in preloader that displays a logo with simple progress bar. See SimplePreloader class for more info.
For more info on how to obtain the source code of this module see this page.