Sometimes, you want to simulate the insides of a building - and not waste much space. This chapter walks you through using Binary Space Partition to sub-divide your dungeon space and make an interior map.

This chapter discusses how to build dungeons using a Binary Space Partition to sub-divide the map into regions, and then place rooms and corridors inside it. It's similar to how Nethack makes its dungeons, and can lead to a fun dungeon-bashing experience.

In order to learn about map building, it's a good idea to be able to see it in progress. This chapter builds a test harness that can `snapshot` each iteration of your map development, and play it as a small movie when a map is created.

So far, we've only had one type of map. That's about to change - but to support it, we need to build a generic Map Builder interface. This chapter walks you through using Rust traits to build a generic interface, and use it to make a varied experience for your player.