I'm refactoring cavern class to create more natural looking caverns. I tried to use Teemu's source code for that, but caverns in Kaduria are much bigger and needed other type of strategy. Then I noticed that I could use Area class to create caverns itself. It almost worked right away. The neat idea in flood filling was that I'm sometimes using 2x2 seeds to make the shape more irregular. Damn it's slow, but look at this:
The round things are actual rooms added after caverns. They don't have corridors yet. The passage routine between caverns is actually buggy, but I guess it could look ok after small rooms (to be added later), because small rooms attach themselves in free areas just like those loose corridor ends. I like the result, although those long straight corridors don't look that good. Maybe this theme needs more caverns after all.