Here is my first cut of the game engine reference intro. Feedback welcome.
The key to understanding the game engine mode is knowing how to prepare your images. The game engine arranges everything into 2D graphics “tiles”. Sprites, Text, Backgrounds are all made up of image tiles.
Tiles are arranged into tile sets. A tile set is a collection of tiles that all have the same width and height. A tile set is like a palette of tiles you can use to create a background or animate a sprite.
Finally a tile set is mapped into a tile atlas (or map of tile sets). A tile atlas mirrors the way images are stored on the GPU hardware. This is part of how the great graphics speed is achieved. In fact, you should expect somewhere around 60 fps in the game engine mode.
In an app where many small tiles are used frequently, it is more efficient to store the tile sets in a tile atlas which is treated as a single unit by the graphics hardware. In particular, because there are less rendering state changes by binding once, it is faster to load one large tile atlas one time than to load many smaller tiles as they are drawn.The following link will always point to the most recent Game Engine Command List.