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>
debris.js: hand-rolled kinematic tumble, drag ∝ speed² so the gust that
spikes a corner is the one that launches the neighbour's bin. Ground bounce
via world.heightAt (contracts.js documents it as ours), sphere-vs-player
knockdown reported to Lane D, sphere-vs-sail-node impulse duck-typed so it
lights up when Lane B exposes nodes and stays silent until then.
skyfx.js: instanced rain that wraps around the camera rather than respawning,
storm sky + procedural cloud dome, lightning, and synthesized WebAudio layers
(wind bed, howl, rain, gust whoosh on the telegraph, rope creak off the worst
corner, flog when one blows). It modulates Lane A's lights and hands them back
on dispose() rather than owning them.
weather_demo.html: graybox bench to drive all three before M0 — mock sail,
storm scrub, 4x, throw-a-crate.
Aligned to contracts.js now that it has landed: relative three imports (there
is no importmap), contracts' rng() instead of a local copy, and storm paths
resolved off import.meta.url — server.py serves the repo root, so an absolute
/world/... would have 404'd at integration.
storm_02: fix the southerly change. contracts.js puts north at -Z and the wind
vector blows toward (cos d, sin d), so the old swing to +2.6 blew toward due
south — a northerly wearing a southerly's name. Now slews to -1.35: a SSW
buster off the open side of the yard, into the house.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Implements the contracts.js wind surface (PLAN3D §4): sample(pos,t) and
gustTelegraph(t), plus storm defs as data.
The prototype scheduled gusts by integrating (wind.gustT += dt). We can't:
sample(pos,t) is called by sail/player/debris/rain at arbitrary t, so gusts
are precomputed into a timeline from a seeded PRNG at load and read from t.
Envelope shape is a faithful port — telegraph 1.5s / ramp 0.8s / hold 1.7s /
fade 1.0s.
Maths lives in weather.core.js with zero imports (no THREE, no DOM, no
Date.now), so the determinism rule is structural and the suite runs in node
without waiting on Lane A's M0.
storm_01_gentle peaks at 11 m/s; storm_02_wildnight sustains 20 m/s and gusts
to 32 (BOM 'destructive'), with the southerly change landing just before the
worst of it — the corners that were slack all storm are the ones that cop it.
15 asserts green: telegraph lead >=1.2s, wind continuity in time and space,
storm JSON validator (incl. 14 deliberately-broken defs it must reject),
determinism, sample-order independence, tree wind shadow.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
