World Generation

Kinsward generates worlds procedurally using noise-based terrain and a 16-step climate simulation pipeline. Each world is unique based on its seed.

Seeds

Set a world seed for reproducible generation:

./kinsward --seed 42
# or
WORLD_SEED=42 ./kinsward

If no seed is provided, one is generated randomly.

Noise-Based Terrain

The base terrain uses Fractal Brownian Motion (FBM) Perlin noise:

Noise Layer	Octaves	Scale	Determines
Elevation	6	0.008	Terrain shape, z-level
Moisture	4	0.012	Biome type (grass/mud/sand)
Temperature	1	0.006	Climate (snow/ice)
Cave	3	0.05	Underground caverns

Elevation to Z-Level

Elevation Value	Z-Level	Terrain
< ~0.12	-2	Deep water
< 0.35	-1	Shallow water
< 0.55	0	Plains
< 0.70	1	Hills
< 0.85	2	Mountains
>= 0.85	3	Peaks

Water z-levels use a continuous formula for smooth depth transitions. Shore zones (elevation 0.35–0.40) generate Sand or Ice blocks at z=0.

Generation depth: 5 blocks below and 4 above the active z-level. Stairs are auto-placed at elevation transitions.

Climate Pipeline

The region map uses a 16-step simulation that runs on a 1024x1024 grid (each cell = 16x16 tiles):

1. Plates & Elevation

Voronoi tectonic plates with boundary uplift and detail noise. Determines the base continental structure.

2. Terrain Conditioning

Thermal erosion and smoothing passes to create natural-looking terrain.

3. Sea Level

Ocean, coast, and land classification via BFS. Computes ocean_distance for each cell.

4. Temperature

Derived from latitude, lapse rate (elevation cooling), and ocean proximity (maritime moderation).

5. Pressure

Hadley cell circulation + thermal pressure + barometric effects + noise + pressure centers.

6. Wind

Pressure gradient force + Coriolis effect + terrain deflection + surface drag.

7. Rainfall

Evaporation from oceans + advection by wind + orographic lift + rain shadow effects.

8. Geology

Rock type assignment from tectonic context. Eight rock types: Granite, Basalt, Sandstone, Limestone, Marble, Slate, Gneiss, Quartzite.

9. Depression Fill

Priority-flood algorithm to remove micro-sinks and ensure water can drain.

10. Drainage

Computed from elevation gradients, slope, and rock permeability.

11. Proto-Rivers

Flow accumulation with lake filling to trace initial river paths.

12. Fluvial Erosion

River valley carving modulated by rock hardness. Harder rocks resist erosion.

13. Final Rivers

Recomputed on the eroded terrain for accurate river placement.

14. Biomes

Assigned from temperature x rainfall x elevation x drainage. 22 biome types (see below).

15. Fertility

Soil fertility derived from rainfall + temperature + drainage + elevation + river proximity.

16. Vegetation

Plant density from biome type + rainfall + temperature + noise variation.

Biomes

The world features 22 biome types:

Biome	Description
Ocean	Open water
Deep Ocean	Far from shore
Beach	Coastal sand
Glacier	Permanent ice
Tundra	Frozen plains
Taiga	Boreal conifer
Boreal Forest	Cold dense forest
Temperate Grassland	Moderate plains
Temperate Forest	Deciduous woodland
Temperate Rainforest	Wet temperate forest
Steppe	Dry grassland
Shrubland	Sparse bushes
Savanna	Tropical grassland
Tropical Forest	Warm woodland
Tropical Rainforest	Dense tropical jungle
Desert	Arid wasteland
Wetland	Swamp/marsh
Floodplain	River-adjacent flat
Montane Forest	Mountain woodland
Alpine	High-altitude meadow
Snow Peak	Mountain summit
Lake	Inland water body

Headless World Generation

The worldgen binary generates worlds without launching the game:

# Generate with a specific seed
worldgen --seed 42

# Export region map layers as PNG
worldgen --seed 42 --layers elevation --format png --out elevation.png

# Export as ASCII
worldgen --layers rivers --format ascii

# JSON output
worldgen --seed 42 --json

Available layers for export: elevation, temperature, rainfall, wind, drainage, rivers, geology, fertility, vegetation, plates, biome.

You can also export region maps from a running game using kinswardctl region-map.