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>
`ready` only meant the graph got built — a suspended AudioContext is still
silent, so there was no way to tell whether the storm was actually audible.
The HUD now reports the real context state.
Verified through it: context runs on first gesture; 7.5 -> 17.8 m/s takes the
wind bed 0.16 -> 0.36 gain while the howl layer goes 0.016 -> 0.104 and the
cutoff opens 428 -> 767 Hz, so a gale reads as a gale and not just a louder
breeze. Rain tracks its curve 0.03 -> 0.32.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Three bugs the bench found once it was actually running a storm:
- Debris was glued to the floor. The scrape `v *= 0.86` ran every frame while
grounded, which is 0.86^60 per second — it pinned a 9 kg crate at 0.7 m/s in
a 19 m/s wind. Friction now applies on impact, with dt-scaled rolling
friction while resting. A crate crosses the whole yard at ~6 m/s.
- Debris slid instead of tumbling: wind is horizontal, so once down there was
no vertical force at all and it skated at constant height. Added tumbling
lift that flips sign as it rolls — bins hop now.
- The cloud dome had a dead straight seam across the sky. The fbm claimed to
tile and didn't; now each octave wraps at its own integer period.
Also: shelters and the bench now use Lane A's landed yard coords (t1 -9,2 /
t2 8,-2, gardenBed 1,2) instead of my guesses, so shelter tuning means
something.
Verified in-browser against a real storm: crate crosses the yard and the t=74
bin spawns from storm JSON; sail node shoved 0.32 m; a 14 kg bin at 20 m/s
knocks the player down and a tub drifting at 0.3 m/s correctly does not;
lightning peaks 0.88. Lane A's selftest: 37 pass / 3 skip.
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>
