The creation of a tileset for large character sets uses a lot of memory. This post shows an approach based on the Flyweight pattern to allow their usage with minimal memory footprint.
This post is part of the OpenGL 2D Facade series
Objective
The objective is similar to the previous one, except that we want to draw characters from large sets, possibly more than 10,000 characters:
With the previous approach, with 10,000 characters and tiles of 29 per 64 pixels, a tileset uses at least 74MB. Even if we save some memory using tricks (like using a single channel rather than four), it is still large. Furthermore, it is for one size and style: we have to create more tilesets for other sizes and styles (bold, italic, shadowed, etc.).
Thanks to this post’s approach, we can create tilesets that only contain the characters we need for the current frame. It is unlikely that a frame has all the characters of a large set, and in usual cases, it is a tiny subset.
In the example above, the program creates the following tileset:
