One link of a sea-level offset STRIP: the water surface offset lerps from
y0 at (x0, z0) to y1 at (x1, z1) across a capsule of the given width.
Chain several (sharing endpoints) to step a river's surface downhill;
overlapping links resolve by max, so joints stay seamless. Keep the
feathered edge inside the channel banks, like the circular regions.
One link of a sea-level offset STRIP: the water surface offset lerps from
y0at (x0, z0) toy1at (x1, z1) across a capsule of the given width. Chain several (sharing endpoints) to step a river's surface downhill; overlapping links resolve by max, so joints stay seamless. Keep the feathered edge inside the channel banks, like the circular regions.