☂️ Game engine: Issues with mapgen

[olanti-p]

We have some issues with our current mapgen infrastructure:

• There are convoluted rules regarding inheritance of mapgens and palettes, which makes the mapgen extremely flexible but hard to reason about
• Mapgen is not deterministic, i.e. it's impossible to set a "seed" for the world, it's always random
• Mapgen variations do not use ids, which makes it impossible to overwrite individual variations or even track down what variations have been used for generating particular piece of map (example issue that could've benefited from this: Odd basement generation #1365)
• OMT boundaries impose some restrictions on placement of buildings and other large-scale objects on map
• OM boundaries can sometimes be visible on water because river/lake worldgen does not look beyond OM borders while doing a smoothing pass - fixed by Smoother rivers connections on overmaps edges #3178
• OMS placement could use some work
• There is no full-featured map maker tool easily available. There are some options, but all of them can mimic only a fraction of JSON power. A lot of difficulty in developing one, as I've discovered, comes from the aforementioned convoluted mapgen rules:
  1. CDDA Hostile Architect, standalone exe
  2. CDDA extension for Tiled level editor tool
  3. BNME, fork of BN with dedicated mapmaker interface based on Dear ImGui