"Rooms" map generation mode

[msakuta]

We want to generate a map with connected free space and "interesting" terrain such as multiple paths and challenging routing. However, none of the methods so far was perfect.

• Perlin noise is good at generating natual looking terrain, but it doesn't guarantee connectivity and sometimes miss a significant portion of map area by disconnection.
• Maze is an attempt to improve it, but it tend to "congest" around the center of the map and not so interesting.

Now we introduce yet another map generation mode called "Rooms".

The algorithm

It is named "Rooms" because the objective is to produce rooms connected with corridors.

First, we generate a set of room "seeds" in a grid pattern. Note that each room is colored by different label in the visualization below because they are disconnected.

Second, we generate connection between rooms.
There are many ways to do this, but in our case, we start from the center and explore ramdonly outwards, similar to Dijkstra algorhtm.

Third, expand some of the rooms to introduce some variation of space.

Fourth, modulate the room positions randomly to add some variation.

Finally, add some Perlin noise to add even more variety and natural looking style.

It can auto-scale as the map resolution increases, but there is a practical limit where the map gets too big that the game won't finish in reasonable time. That said, it's cool to see many agents can navigate this huge maps in real time.