The sea over a patch: the datum sphere, meshed on the patch's own grid.
A second surface rather than a color on the first, because a shore seen
from a landed ship is a flat sheet meeting a slope, and the ground under it
is a seabed the sheet is looked through. The vertices are anchor-relative
for the reason the patch's are, and they morph onto the parent's grid for
the reason the patch's do: the parent's sheet is the parent's chord of the
same sphere, and a child whose sheet did not slide onto it would show a
sliver of seabed along every level boundary. depths is the one thing the
material cannot derive — the ground under the sheet — and it morphs with
the rest so the shallows do not shimmer at the handover.
Members
boundsCenterreadonly
Bounding sphere in the same anchor-relative axes the vertices are in.
boundsRadiusreadonly
depthsreadonly
Water level minus the ground, meters, never negative. Zero where the ground is dry.
morphDepthsreadonly
morphPositionsreadonly
Where each vertex sits once fully morphed onto the parent's grid.
positionsreadonly
xyz triples in body-fixed axes, relative to the patch's anchor, at
each vertex's own water level: the sea's datum, a lake's spill or a
river's surface, whichever stands highest there — and a step under the
ground where nothing does, so the sheet hides rather than z-fights.