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feat: shelf-edge variation -- the red-line scalloping (terrain-water task 10)

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PASS B, replacing the reverted incision. The developer's sketch asked for
the shelf/riser BOUNDARY to be organic, not for water: notches, coves and
small peninsulas where a flat shelf meets its riser, instead of the clean
oval contour the curve produces.

Mechanism (the task's preferred "boundary warp", in its most
monotonic-safe form): every shelf/riser boundary is the contour where the
raw height crosses K3, K4 or K5, so the boundary is warped by SLIDING
THOSE THREE KNOTS per column -- edgeShift = simplex(resolvedSeed + 7507,
12 per island width) x ShelfEdgeVariation. The contours then wander in and
out of the terrain instead of tracing an iso-height line. Noise-warped by
construction, so there is no grid direction for an artifact to line up on
-- the failure mode of the thing this replaces.

Why slide knots rather than perturb a weight or the input height:
monotonicity becomes structural instead of conditional. The curve is
strictly monotonic for ANY ordered knot set, so no derivative bound, no
amplitude-vs-feather-width tuning, no way for a dial to invert a column.
MaxEdgeShift keeps the set ordered (half the smallest margin to a fixed
knot = 12.3 m of input height for the v5 knots); the config dial is
clamped to it, loudly. AssertMonotonic now sweeps 24 corners -- the 8
modulation extremes x {-max, 0, +max} shift -- and checks the bound first.

K1, K2 and K6 never move, which buys the guarantees exactly rather than
statistically: below K2 and above K6 a warped column is bit-identical to
an unwarped one, so the red ceiling still floors every shelf edge (storm
ladder safe), the 420 m cap still caps, and the toe and summit spikes are
untouched. The block slides rigidly, so the bench and mid-riser keep their
exact widths -- shelf interiors stay flat, riser interiors keep their
profile, and only the foothill riser and plateau stretch to absorb it.
The micro-relief mask takes the same shift, so pass A's skin follows the
shelf wherever pass B moved its edge.

Dial ShelfEdgeVariation (default 5 m of INPUT height -- a boundary
displacement, not an elevation change) under the existing TerrainDetail
gate; both passes stay one judged unit. TDTL v2 body records relief and
edge amp/frequency/seed-offset plus the applied clamp bound; writer,
parser and harness follow. No blueprint was written between the revert
and this commit, so v2 only ever means relief + edge warp on disk.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
This commit is contained in:
Stewart Howe 2026-08-08 20:31:41 -04:00
parent 3b6d166458
commit 492b56a87c
7 changed files with 182 additions and 69 deletions
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4
Tools/Scripts/RoundTripHarness.cs
View file

@ -229,8 +229,8 @@ public partial class RoundTripHarness : Node
return false;
}
var da = a.TerrainDetail; var db = b.TerrainDetail;
float[] fa = { da.Version, da.ReliefAmpM, da.ReliefFreqIslands, da.ReliefSeedOffset };
float[] fb = { db.Version, db.ReliefAmpM, db.ReliefFreqIslands, db.ReliefSeedOffset };
float[] fa = { da.Version, da.ReliefAmpM, da.ReliefFreqIslands, da.ReliefSeedOffset, da.EdgeAmpM, da.EdgeFreqIslands, da.EdgeSeedOffset, da.EdgeMaxShiftM };
float[] fb = { db.Version, db.ReliefAmpM, db.ReliefFreqIslands, db.ReliefSeedOffset, db.EdgeAmpM, db.EdgeFreqIslands, db.EdgeSeedOffset, db.EdgeMaxShiftM };
for (int i = 0; i < fa.Length; i++)
if (System.BitConverter.SingleToInt32Bits(fa[i]) != System.BitConverter.SingleToInt32Bits(fb[i]))
{