Dungeons are generated via Images that tell how the dungeon gets generated.
Each pixel rapresents a different kind of entity. We can clearly distinguish tiles and backgrounds.
Pink pixels will accept "anything", or are basically "blank" pixels. For the sake of random generation, will not alter the area where they're placed.
Gray pixels are the main biome's blocks depending on the biome the entrance will be put in.
Blue pixels tell the engine that there should be a connected room in that location).
Black pixels will tell the gen that there should be no tile in that location, leaving an open "sky" or "air" area.
Some examples:
in the engine
after, the famous photo from tiy's post.
bubbles!