NOTE:
This tutorial includes the use of a paid plugin from Scirra Store.
In my previous tutorial for this topic I showed how to trick/mask the lag that occurs while switching between layouts.
In this tutorial, there will be no tricks. I'll show you how to make a real preloading with MM_Preloader plugin.
The problem
A lot happens during transition from one layout to another. Objects have to be loaded, instances have to be created, sprite images have to be loaded, engine has to release old data from the memory, etc.
From all those operations, the most heavy one is loading sprite's image. The engine has to read the PNG/JPG file, decompress it to bitmap and place in memory. The more images and the bigger images are there on the next layout, the bigger the lag is.
The solution is in the MM_Preloader plugin.