Step-generator form of generateChunkTerrain: yields the fraction of
the land budget placed so far (0–1) after each raise/sink round, so async
drivers can suspend between rounds. Deterministic — the rand call order is
identical to the synchronous version.
Step-generator form of generateChunkTerrain: yields the fraction of the land budget placed so far (0–1) after each raise/sink round, so async drivers can suspend between rounds. Deterministic — the
randcall order is identical to the synchronous version.