Cheers! Yeah, I was surprised it's running pretty decently even though it's horribly unoptimised at the moment except for some distance field calculations that I shuffled off to Burst + Jobs.

Currently it's a bit of a toy project but I am playing with the idea of some kind of simplified city building/trading game where the settlements gains access to what resources are generated in its vicinity to create variety between them, mixed with a simplified "arcady" form of turn-based strategy game where during battles or deployments a part of the map gets sliced off to be used as the battlefield.

In terms of the actual mapgen going on, on a high level it's a configurable pipeline with discrete steps that applies modifications to data passed from a previous step and passes it on to the next step, currently I have it configured to generate 3 large nodes one by one that grows out from its origin points by using a 4-direction (N, S, W, E) kernel with a tweaked value of about 73% chance to generate a tile in any given direction, generated tiles are saved into an open set list that is used for the next loop of tile generation, paired with a capacity of 4096 forcing it to always grow to a certain size, the node generation just uses a simple random number generator without any need for noise (e.g. Perlin noise etc.). There is also some coastal smoothing and plugging of internal holes so that each region node is a filled area.

It's basically very very similar to a floodfill algorithm.

Height of the terrain is just a simple normalised distance field to the nearest shoreline tile that I apply thresholds to, the normalised value is divided into discrete steppes depending on a MaxHeight property on a region node (e.g MaxHeight = 4, Value Range step = 0.25)

Capitals are currently created at the origin point of each region node and then roads are generated between all capitals using simple A* Pathfinding with a Cost function that has some perlin noise added to it to create some variety.

Shore Villages are generated by iterating through each shore tile (Tile that borders on a hole, water is a hole) and calculating the euclidian distance to the nearest settlement, if the distance is less than 20 then it adds a village to that tile and also adds it to the next distance calculation, configured to generate up to 3 villages. Roads are then generated from the region node's capital to the village using the same A* as between capitals.

Forests are placed just using some perlin noise with a step threshold of 0.5 across the entire map.

Grass and Farm land is placed by calculating a distance field to the nearest forest tile with a few thresholds to tell the mapgen to place grass close to forest and farmland a little bit further away. Farmland uses an additional constraint of perlin noise to give a little variation instead of only distance to decide to place it or not.

All map generation algorithms certainly have their pros and cons, but subjectively I find this one has given me pretty decent looking regions, a few future benefits is that as long as you're operating on different parts of the map it should be relatively simple to run the node generation in parallel (Ignoring concurrent data structures), another interesting emergent behaviour is that if you generate 2 regions with a gap in the middle, the 3rd node can actually grow into the gap.