Reshapes land elevation by blending it with a distance-from-coast field:
every land cell's target height grows with its BFS distance from the
nearest water, normalized by the farthest interior point. Water cells are
never touched, and land never drops below 0 or above elevationMax, so the
land/water split the chunk stage placed is preserved exactly.
Runs between the landmass and mountain-range passes: ranges then rise from
an interior that is already the high ground. Deterministic and rand-free.
Reshapes land elevation by blending it with a distance-from-coast field: every land cell's target height grows with its BFS distance from the nearest water, normalized by the farthest interior point. Water cells are never touched, and land never drops below 0 or above elevationMax, so the land/water split the chunk stage placed is preserved exactly.
Runs between the landmass and mountain-range passes: ranges then rise from an interior that is already the high ground. Deterministic and rand-free.