04-24-2020, 01:06 AM
Classic 2D chipsets couldn't fit the entire map of a level in video RAM, but only a small portion, a little bigger than the screen. Game code had to copy or "stream" tiles on the fly from the full level that resided in cartridge ROM, to the video RAM as the player advanced. This is the intended use of TLN_CopyTiles(). However in Tilengine you load the entire map and scroll freely on it, so this feature isn't really useful unless you want to emulate this specific limitation of classic systems.