SPRINT2 decisions 3 and 5, plus Lane A's fog nit.
Decision 3 — gusts now descend. Cloth pressure goes with dot(wind, normal); a
flat panel's normal points at the sky, so in a perfectly horizontal wind the
dot is ~0 and "lie it flat and ignore the storm" was the cheapest winning rig.
A gust front is descending air, not just faster air. Per-gust downdraft
fraction in storm JSON (storm_02 0.3, storm_01 0.18, default 0.25, validated
0..1), each gust varying 0.6-1.4x. Peak downdraft in storm_02 is 4.4 m/s, 17%
of the horizontal. Lane B: the cloth-side assert is yours.
The vertical draws from its OWN rng stream, and there's an assert pinning
that: pulling it from the main stream would shift every subsequent (t0, pow)
and silently re-time storms Lane A has already hand-verified. Their carabiner
still blows at t=45.4 and cascades at t=56.
speedAt() stays horizontal — an anemometer doesn't read falling air, and a
wind meter that spikes because a gust is descending reads as a bug.
Decision 5 — debris.pieces frozen and documented in contracts.js as the seam
Lane B reads in sail.step(), with the sphere/SI/mutated-in-place semantics
spelled out and an assert tying the live shape to the contract table.
Fog: dispose() captured scene.fog by reference and step() mutates that object
in place, so restoring it restored nothing (Lane A caught it). Now captured by
value, and fog we created ourselves is removed rather than left behind.
Selftest 130/0/0 (was 121); Lane C 28 asserts.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Decision 4 — conform to Lane D's call sites rather than the reverse (D
landed first and duck-typed them): repair(i), trim(i, delta) and
cornerPos(i). repair takes no hardware argument because prep sells
exactly one kind of spare, so it re-rigs at shackle grade — an upgrade
on a blown carabiner, a downgrade on a blown rated shackle, which is the
prototype's behaviour and a real choice about which corner you run to.
cornerPos returns a fresh vector at the live node, so a blown corner's
prompt chases the flogging corner instead of sitting on a dead anchor
(measured: 13 m off). All three are contract entries now, not PROPOSED
comments, so the merge tripwire enforces the seam.
Decision 5 — sail.step() takes an optional debris and applies sphere-vs-
cloth impulses. The exchange is symmetric: every newton-second the cloth
takes out of a crate, the crate loses. Asserted, and it conserves to
0.000% on an interior hit. Pinned corners are the deliberate exception —
invMass 0 means a crate off a corner dumps its momentum into the house,
which is correct, the anchor is bolted to a wall.
Note this leaves debris.js's applyToSail dead: it guards on `sail.nodes`,
which never existed on the rig — the cloth stores Float64Arrays. So the
debris-vs-sail impulse has been silently doing nothing in the assembled
game. Decision 5 puts it on this side; flagged for Lane C in THREADS.
The contact radius is swept by the piece's travel because main.js steps
the sail before the debris (so piece positions are a frame stale) and a
0.3 m crate at 25 m/s covers 0.42 m per frame — enough to pass clean
between cloth nodes.
Also: coverageOver() rays now start at heightAt(x,z) rather than y=0.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Rebased onto M0 and reconciled against the real spine. checkContract
('sailRig') now conforms and js/tests/b.test.js runs 28 asserts green.
Contract fixes:
- anchor.sway(t) is the ABSOLUTE position, not an offset (thanks A —
I had it adding sway to pos, which would have flung every
tree-anchored corner to double its coordinates).
- events is an Emitter emitting {type, corner}, not a drained array.
- coverageOver() rects are centre+size, matching world.gardenBed. It
consumes world.sunDir directly: a hit along sunDir means shaded.
- START_BUDGET/SPARE_COST/HARDWARE/FIXED_DT now come from contracts.js
rather than being redeclared here.
Bug: a corner that blew was marked broken but never had its mass
returned, so invMass stayed 0 and the "blown" corner sat welded in
mid-air — no flogging, and the sail silently went dead. PLAN3D §5-B
wants flogging emergent from the freed node, so _checkFailure now frees
it. The cascade test missed this because it called _repin() by hand;
the new test drives a real overload failure instead and asserts the
corner tears 2 m off its anchor and keeps moving.
Tension dial remapped from the prototype's rest/tension to a real
pre-strain. rest/tension asks for 17% strain at dial 1.2 and 29% at 1.4
— stretching an 18 m sail by three metres — and put 68 kN on a corner of
the yard's biggest quad with no wind blowing. At 0.10 strain-per-dial it
swings a 5x5 rig's peak load 2.1x loose-to-tight and redlines a 192 m2
quad at 8.3 kN drum-tight, which is punishing and correct.
HARDWARE ratings retuned in contracts.js to real newtons per the
standing note there that Lane B owns these numbers. Costs and tier shape
untouched; $80 still buys rated hardware on at most 2 of 4 corners.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Types, tuning constants ported from the prototype, a seeded PRNG and Emitter,
plus checkContract() — the tripwire that catches a lane drifting from its
interface at merge time instead of three lanes later.
createStubWind() ports the prototype's gust shape (telegraph 1.5s, ramp 0.8s,
hold 1.7s, fade 1.0s) so B and D can develop before Lane C lands weather.js.
Its schedule is precomputed at construction, which keeps sample() pure in t —
the selftest samples out of order and must get the same answer.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
