The gust-only downdraft could not satisfy B's 60% no-free-lunch bar and the §7
twisted-survives gate together: the downdraft peaked at the gust peak, where
the horizontal peaked too, so a flat sail never reached 60% of a pitched one's
load without a spike so violent it also broke the twisted rig. The integrator
measured the pincer (0.58 -> 48% and still breaks twisted).
Fix: the downdraft is now a fraction of the LOCAL total wind speed, not of gust
power (weather.core verticalAt = -frac * localHoriz). It presses a flat roof
steadily across the whole storm — peak total 32.6 m/s dwarfs peak gust power
12.6 — so the ratio clears 60% at a gentle fraction, with no gust-peak spike.
It rides the local speed, so a tree's wind shadow shelters from falling air too.
speedAt() stays horizontal (a wind meter doesn't read falling air).
Field renamed downdraft -> downdraftOfTotal; the validator rejects the old name
rather than silently re-meaning it. The vertical now carries NO rng draws at
all, so the determinism guarantee (tuning can't re-time gusts) is structural,
not just separate-stream.
Measured both gates myself with B's SailRig (8-direction flat-vs-pitched sweep +
§7 legs). Target for storm_02 is 0.45: 69% of-max / 60% worst-heading on the
bar, twisted rated rig survives with ~21% margin. HELD at 0.12 this commit —
the current yard's only twisted quad ('h1,t2,p1,t1', ~190 m2) starts losing a
corner near 0.15 in the exact solver, so 0.45 would red B's §7. 0.12 ~= the old
gust-only 0.3 in peak downdraft (-4.2 vs -4.5 m/s). Bump to 0.45 is a one-number
joint step once A lands decision-2 anchors (18-45 m2 quads) and B re-points §7.
storm_03_southerly: campaign ramp between gentle and wildnight — peak gust 21
m/s, sustained 13, one moderate southerly change. Auto-swept by the suite.
Selftest 170/0/0 (all three §7 legs green). Verified live: downdraft/horizontal
ratio is exactly 0.12 in-game, rain occlusion still covers the bed.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The garden visibly stays dry under the sail. Rain arrives along the wind, so
the dry patch sits downwind of the cloth and slides across the yard as the
wind swings — at the southerly change it walks right off the bed, free drama
and honest physics.
Cheap on purpose. Ray-testing 3k drops against 162 triangles every frame is
~486k intersections for an effect nobody inspects closely. Instead project the
sail's triangles ALONG the rain onto the ground into a coarse height grid, a
few times a second (the cloth moves slowly next to the rain); per-drop cost is
one grid read, and occluded drops get a zero-scale matrix rather than a
raycast. Measured 0.041 ms/rebuild, 10x/s = 0.41 ms/s against A's 0.63 ms
frame — negligible. Reads rig.pos/rig.tris, so nothing new needed from Lane B.
Verified in the real game with a surviving twisted rated rig: 497 grid cells
covered, 96% of the garden bed under cover, live drops culled under the cloth
and falling in the open yard either side. Screenshot for DESIGN.md.
skyfx exposes rainShadowOver(rect) — NOT the same as rig.coverageOver(bed,
sunDir). That one is the SUN shadow; this is the RAIN shadow (down the wind).
Which drives garden HP is a design call — flagged for A in THREADS.
Selftest 134/0/0 (8 new rain-shadow asserts).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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>
selftest.html only imports; each lane owns js/tests/<letter>.test.js. Five lanes
sharing one selftest.html would be the single guaranteed merge conflict in the
repo, so the stubs are pre-created with each lane's PLAN3D asserts written into
the header.
No rAF anywhere: it's throttled in a hidden tab, so a rAF-driven selftest would
pass only while you watch it. fixedLoop() drives time instead.
Lane A's suite covers the §5-A acceptance criteria, including "camera never
clips through house" — stated as the underlying invariant (no solid between the
player's head and the camera) so it survives Lane E swapping the house GLB.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
