A living map, coast to snow line

Climate is the stored primitive; biome is a label draped over it. The generator bakes smooth temperature, rainfall, elevation, and slope fields, then runs a Whittaker-style lookup over temperature and rainfall (extended with elevation) to assign a biome. Because the inputs are continuous, transitions blur for free: forest thins to woodland to grassland with no edge, while genuine thresholds (snow line, tree line) survive as cutoffs on temperature plus an elevation lapse rate. Biome id never drives rendering; it is a convenience layer for spawn rules and the where-am-I readout.

Flora is scattered assets, not block types. The built proof-of-concept uses godot_voxel's VoxelInstancer (MultiMesh for dense ground cover, scene items with collision for trees), filtered by the climate fields. Each surface voxel carries an 8-bit biome id, and every flora layer filters on that id, so per-biome flora drops in without fighting the engine's four-channel texture limit. The catalog binds each plant to the band it tolerates: the climate gate runs first, then placement, so a plant never appears outside ground it could actually live on.

The full pipeline (per-band scatter density, cultivated-only crops in a farmland mask, hand-placed arcane flora at anomaly sites) is designed and partly proven. The capital coast is mediterranean by classification; the same fields feed farming fertility (biome, rainfall, flatness) and settlement placement, so ecology and economy read from one source.

• Ten land biomes plus open water and ice, classified planet-wide from the climate fields.
• Whittaker classification: temperature (latitude plus elevation lapse) and rainfall (latitude bands plus noise) map to a biome label.
• Biome is stored as an 8-bit per-voxel id; each flora layer filters on that id for per-biome scatter.
• Climate gate runs before rarity: a plant outside its temperature/moisture band never spawns there, regardless of how common it is elsewhere.
• Built: the VoxelInstancer flora scatter POC and the biome classification; per-species placement is designed. Spawn weights and worldgen params are withheld.