From 135511fb0523d08335e5acaae29be92a0c853049 Mon Sep 17 00:00:00 2001 From: m3ultra Date: Thu, 16 Jul 2026 23:58:31 +1000 Subject: [PATCH] Add vertical gusts, freeze debris.pieces, fix fog restore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 --- web/world/data/storms/storm_01_gentle.json | 3 +- web/world/data/storms/storm_02_wildnight.json | 5 +- web/world/js/contracts.js | 56 ++++++++++++ web/world/js/skyfx.js | 20 +++- web/world/js/tests/c.test.js | 90 +++++++++++++++++- web/world/js/tests/weather.selftest.js | 91 +++++++++++++++++++ web/world/js/weather.core.js | 52 ++++++++++- 7 files changed, 306 insertions(+), 11 deletions(-) diff --git a/web/world/data/storms/storm_01_gentle.json b/web/world/data/storms/storm_01_gentle.json index d76f06a..259194e 100644 --- a/web/world/data/storms/storm_01_gentle.json +++ b/web/world/data/storms/storm_01_gentle.json @@ -13,7 +13,8 @@ "maxGap": 14, "powBase": 2, "powRand": 3, - "powRamp": 2 + "powRamp": 2, + "downdraft": 0.18 }, "dirCurve": [[0, 0.9], [45, 1.0], [90, 1.15]], diff --git a/web/world/data/storms/storm_02_wildnight.json b/web/world/data/storms/storm_02_wildnight.json index 91299ac..0508b82 100644 --- a/web/world/data/storms/storm_02_wildnight.json +++ b/web/world/data/storms/storm_02_wildnight.json @@ -11,13 +11,16 @@ "baseCurve": [[0, 7.0], [15, 11.0], [40, 17.0], [60, 20.0], [78, 19.0], [90, 16.0]], + "_gusts_comment": "downdraft = fraction of gust power that blows DOWN, per gust (each gust varies 0.6-1.4x this). A gust front is descending air, not just faster air; without it a flat horizontal sail sheds everything and ignoring the storm is the winning move. 0.3 here because a wild night should punish a flat rig hard.", + "gusts": { "firstAt": 3, "minGap": 5.5, "maxGap": 11, "powBase": 3, "powRand": 5, - "powRamp": 7 + "powRamp": 7, + "downdraft": 0.3 }, "dirCurve": [[0, 0.85], [50, 0.95], [55, 0.6], [59, -1.25], [70, -1.45], [90, -1.35]], diff --git a/web/world/js/contracts.js b/web/world/js/contracts.js index 5219bc3..a310041 100644 --- a/web/world/js/contracts.js +++ b/web/world/js/contracts.js @@ -190,6 +190,48 @@ export class Emitter { * @property {boolean} broken */ +/** + * DEBRIS — Lane C implements. Lane B consumes `pieces` inside sail.step(). + * + * SPRINT2 decision 5: the sail reads the pieces and applies its own impulses, + * rather than debris.js reaching into the cloth. Momentum bookkeeping stays in + * the one integrator that owns the nodes. That makes `pieces` a real contract + * surface, so it is **frozen** here: fields below are what Lane B may rely on. + * + * @typedef {object} Debris + * @property {DebrisPiece[]} pieces + * Live pieces, newest last. The ARRAY IS MUTATED IN PLACE each step — pieces + * are spliced out when they leave the yard, so don't hold a reference to it + * across frames, and don't hold a piece past the step it despawned in. Read it + * fresh inside step(). Order is not stable. + * @property {(dt:number, t:number, world?:object) => void} step Fixed dt. Deterministic. + * @property {(ev:object, t:number) => DebrisPiece} spawn + * @property {(map:Object) => Debris} setModels + * @property {() => void} clear + */ + +/** + * One airborne object. Frozen shape — Lane C will not remove or repurpose these. + * + * The collision volume is a SPHERE of radius `r` centred on (x,y,z): a crate is + * boxy, but a sphere is what you can afford to test against every cloth node, + * every frame. Everything is SI — metres, m/s, kg — so `mass * v` is a real + * momentum you can subtract from. + * + * @typedef {object} DebrisPiece + * @property {number} x + * @property {number} y Centre, not base. Rests at heightAt(x,z) + r. + * @property {number} z + * @property {number} vx + * @property {number} vy + * @property {number} vz + * @property {number} r Collision sphere radius, m. + * @property {number} mass kg. Crate 9, tub 5, bin 14. + * @property {string} model Key into models/debris/, e.g. 'BlueCrate_v2'. + * @property {boolean} hitPlayer Already knocked the player down once. + * @property {THREE.Object3D|null} mesh Render instance. Lane C drives it; don't move it. + */ + /** * PLAYER — Lane D implements. * @@ -258,6 +300,20 @@ export const CONTRACT = { interact: { register: 'function' }, camera: { object: 'object', yaw: 'number', update: 'function' }, game: { phase: 'string', on: 'function' }, + debris: { pieces: 'object', step: 'function', spawn: 'function', setModels: 'function', clear: 'function' }, +}; + +/** + * The frozen DebrisPiece fields (SPRINT2 decision 5). Lane B's sail.step() reads + * these off `debris.pieces` and applies impulses from them, so renaming one is a + * breaking change to someone else's integrator, not a local tidy-up. Asserted + * against live pieces in c.test.js — if this table and debris.js disagree, the + * selftest says so before Lane B's cloth does. + */ +export const DEBRIS_PIECE_FIELDS = { + x: 'number', y: 'number', z: 'number', + vx: 'number', vy: 'number', vz: 'number', + r: 'number', mass: 'number', model: 'string', }; /** diff --git a/web/world/js/skyfx.js b/web/world/js/skyfx.js index 030576e..0877b40 100644 --- a/web/world/js/skyfx.js +++ b/web/world/js/skyfx.js @@ -337,10 +337,19 @@ export function createSkyFx(o = {}) { dome.renderOrder = -1; if (scene) scene.add(dome); - // remember what world.js handed us, so dispose() puts it back exactly + // Remember what world.js handed us, so dispose() puts it back exactly. + // Fog is captured BY VALUE, not by reference: step() mutates that very object + // in place, so `scene.fog = original.fog` restores the object we just spent a + // storm wrecking. Lane A caught it — sun and hemi came back exactly and the fog + // stayed where the storm left it. Harmless today only because the next skyfx + // immediately re-drives it, which is exactly the kind of bug that waits. + const ownsFog = !!scene && !scene.fog; const original = { background: scene ? scene.background : null, fog: scene ? scene.fog : null, + fogColor: scene && scene.fog ? scene.fog.color.clone() : null, + fogNear: scene && scene.fog ? scene.fog.near : 0, + fogFar: scene && scene.fog ? scene.fog.far : 0, sun: sun ? sun.intensity : 0, hemi: hemi ? hemi.intensity : 0, }; @@ -454,7 +463,14 @@ export function createSkyFx(o = {}) { scene.remove(rain.mesh); scene.remove(dome); scene.background = original.background; - scene.fog = original.fog; + if (ownsFog) { + scene.fog = null; // we brought it; we take it + } else if (original.fog) { + scene.fog = original.fog; + original.fog.color.copy(original.fogColor); + original.fog.near = original.fogNear; + original.fog.far = original.fogFar; + } } if (sun) sun.intensity = original.sun; if (hemi) hemi.intensity = original.hemi; diff --git a/web/world/js/tests/c.test.js b/web/world/js/tests/c.test.js index a74f905..5348546 100644 --- a/web/world/js/tests/c.test.js +++ b/web/world/js/tests/c.test.js @@ -15,8 +15,10 @@ import * as THREE from '../../vendor/three.module.js'; import { assert, fixedLoop } from '../testkit.js'; -import { FIXED_DT, checkContract } from '../contracts.js'; +import { FIXED_DT, checkContract, DEBRIS_PIECE_FIELDS } from '../contracts.js'; import { loadStorm, createWind } from '../weather.js'; +import { createDebris } from '../debris.js'; +import { createSkyFx } from '../skyfx.js'; import { weatherCases } from './weather.selftest.js'; const STORMS = ['storm_01_gentle', 'storm_02_wildnight']; @@ -43,12 +45,34 @@ export default async function run(t) { const pos = new THREE.Vector3(3, 0, -2); const a = wind.sample(pos, 12.5); assert(a instanceof THREE.Vector3, 'sample did not return a THREE.Vector3'); - assert(a.y === 0, `wind should be horizontal, got y=${a.y}`); + assert(Number.isFinite(a.x) && Number.isFinite(a.y) && Number.isFinite(a.z), + `sample returned a non-finite vector: ${a.x},${a.y},${a.z}`); // out param must not change the answer, only where it lands const out = new THREE.Vector3(); const b = wind.sample(pos, 12.5, out); assert(b === out, 'out param was ignored'); - assert(a.x === b.x && a.z === b.z, 'out param changed the result'); + assert(a.x === b.x && a.y === b.y && a.z === b.z, 'out param changed the result'); + }); + + // This assert used to read `a.y === 0` — "wind should be horizontal". SPRINT2 + // decision 3 made that false on purpose: gusts now descend, which is what makes + // a flat sail pay. Keeping the useful half — y is downward-or-zero, never up, + // and never garbage — so player shove and rain angle can still trust the sign. + t.test('vertical wind is downward-only, and only during gusts', () => { + const wind = createWind(storms.storm_02_wildnight); + const pos = new THREE.Vector3(0, 1.7, 0); + const v = new THREE.Vector3(); + let sawDown = false; + fixedLoop(wind.duration, FIXED_DT, (dt, time) => { + wind.sample(pos, time, v); + assert(v.y <= 1e-9, `wind blew UP (y=${v.y.toFixed(3)}) at t=${time.toFixed(2)}`); + if (v.y < -1) sawDown = true; + }); + assert(sawDown, 'never saw a downdraft worth the name in a whole wild night'); + // and the wind meter must stay horizontal — a falling gust shouldn't spike the HUD + const calm = wind.speedAt(pos, 0.5); + assert(Math.abs(calm - Math.hypot(wind.sample(pos, 0.5).x, wind.sample(pos, 0.5).z)) < 1e-9, + 'speedAt() is not the horizontal magnitude of sample()'); }); // Lifted from a.test.js onto the real wind (Lane A's note in this file's @@ -70,6 +94,66 @@ export default async function run(t) { assert(edges >= 5, `only ${edges} gusts telegraphed in a ${wind.duration}s storm — too quiet to test`); }); + // --- SPRINT2 decision 5: debris.pieces is Lane B's to read, so it's frozen --- + t.test('debris conforms and its pieces match the frozen shape', () => { + const wind = createWind(storms.storm_02_wildnight); + const debris = createDebris({ wind }); + assert(checkContract('debris', debris).length === 0, checkContract('debris', debris).join('; ')); + + const p = debris.spawn({ model: 'BlueCrate_v2', lateral: 0 }, 40); + for (const [field, want] of Object.entries(DEBRIS_PIECE_FIELDS)) { + const got = typeof p[field]; + assert(got === want, `piece.${field} is ${got}, contract says ${want}`); + if (want === 'number') assert(Number.isFinite(p[field]), `piece.${field} is not finite`); + } + assert(debris.pieces.includes(p), 'spawn() returned a piece that is not in pieces'); + assert(p.r > 0 && p.mass > 0, 'a piece with no radius or no mass cannot be collided with'); + + // The array is mutated in place and pieces are spliced on despawn — that's + // documented, and B reads it fresh inside step(). Prove clear() empties it + // rather than swapping in a new array behind their reference. + const ref = debris.pieces; + debris.clear(); + assert(ref === debris.pieces && debris.pieces.length === 0, + 'clear() replaced the pieces array instead of emptying it — B holds a reference'); + }); + + // Lane A rebuilds skyfx on every phase change, so dispose() is on the hot path. + // They verified sun/hemi restore exactly and spotted that fog didn't; this pins + // both. The vacuity guards matter — a restore test where nothing ever moved is + // a test that passes forever and checks nothing. + t.test('skyfx.dispose() hands the scene back exactly as it found it', () => { + const scene = new THREE.Scene(); + scene.background = new THREE.Color(0x9fc4e8); + scene.fog = new THREE.Fog(0x9fc4e8, 30, 140); + const camera = new THREE.PerspectiveCamera(); + const sun = new THREE.DirectionalLight(0xfff4e0, 2.0); + const hemi = new THREE.HemisphereLight(0xbfd8ff, 0x3a4a2a, 1.8); + const before = { + bg: scene.background, fogColor: scene.fog.color.getHex(), + fogNear: scene.fog.near, fogFar: scene.fog.far, + sun: sun.intensity, hemi: hemi.intensity, children: scene.children.length, + }; + + const wind = createWind(storms.storm_02_wildnight); + const sky = createSkyFx({ scene, camera, wind, sun, hemi }); + fixedLoop(40, FIXED_DT, (dt, time) => sky.step(dt, time, {})); + + assert(sun.intensity < before.sun * 0.9, 'the storm never dimmed the sun — this test proves nothing'); + assert(scene.fog.near !== before.fogNear, 'the storm never touched the fog — this test proves nothing'); + + sky.dispose(); + assert(sun.intensity === before.sun, `sun left at ${sun.intensity}, want ${before.sun}`); + assert(hemi.intensity === before.hemi, `hemi left at ${hemi.intensity}, want ${before.hemi}`); + assert(scene.background === before.bg, 'scene.background not restored'); + assert(scene.fog.color.getHex() === before.fogColor, + `fog colour left at #${scene.fog.color.getHex().toString(16)}, want #${before.fogColor.toString(16)}`); + assert(scene.fog.near === before.fogNear && scene.fog.far === before.fogFar, + `fog left at near=${scene.fog.near} far=${scene.fog.far}, want ${before.fogNear}/${before.fogFar}`); + assert(scene.children.length === before.children, + `skyfx left ${scene.children.length - before.children} object(s) in the scene`); + }); + t.test('every storm in data/storms/ loads and validates', () => { // loadStorm throws on invalid, so reaching here with all of them is the pass assert(Object.keys(storms).length === STORMS.length, 'a storm failed to load'); diff --git a/web/world/js/tests/weather.selftest.js b/web/world/js/tests/weather.selftest.js index 29ca7d6..e0e9ffb 100644 --- a/web/world/js/tests/weather.selftest.js +++ b/web/world/js/tests/weather.selftest.js @@ -280,6 +280,97 @@ export function weatherCases(storms) { assert(Math.abs(luvS - luvB) < 1e-9, 'upwind side is being sheltered — shadow is pointing the wrong way'); }); + // ---- 9. vertical gust structure (SPRINT2 decision 3) ---- + // Cloth pressure goes with dot(wind, normal). A flat horizontal panel's normal + // points at the sky, so in a perfectly horizontal wind that dot is ~0 and the + // cheapest winning rig is "lie it flat and ignore the storm" — the opposite of + // the game. Gust fronts are descending air, and descending air hits a flat + // panel square on. Lane B owns the cloth-side assert; these are the wind side. + test('gusts carry a downdraft, and still air does not', () => { + const f = createWindField(storms.storm_02_wildnight); + let peakDown = 0, betweenMax = 0; + for (let t = 0; t <= f.duration; t += DT) { + const v = f.gustVertical(t); + assert(v <= 1e-12, `vertical wind went UP (${v.toFixed(2)}) at t=${t.toFixed(2)} — downdraft only`); + const live = f.gusts.some((g) => t > g.t0 && t < g.endAt); + if (live) peakDown = Math.min(peakDown, v); + else betweenMax = Math.max(betweenMax, Math.abs(v)); + } + metrics['storm_02.peakDowndraft'] = +peakDown.toFixed(2); + assert(betweenMax === 0, `air is falling between gusts (${betweenMax}) — downdraft must be a gust feature`); + assert(peakDown < -2, `peak downdraft only ${peakDown.toFixed(2)} m/s — a flat sail would still shrug it off`); + }); + + test('downdraft tracks its own gust and its JSON fraction', () => { + const def = storms.storm_02_wildnight; + const f = createWindField(def); + const frac = def.gusts.downdraft; + for (const g of f.gusts) { + assert(g.down >= frac * 0.6 - 1e-9 && g.down <= frac * 1.4 + 1e-9, + `gust at t=${g.t0.toFixed(1)} has down=${g.down.toFixed(3)}, outside 0.6–1.4× of ${frac}`); + // minGap >= GUST.TOTAL means gusts never overlap, so at hold it's exactly this gust + const atHold = f.gustVertical(g.t0 + 3); + assert(Math.abs(atHold - -(g.pow * g.down)) < 1e-9, + `at gust hold vertical is ${atHold.toFixed(3)}, want ${(-g.pow * g.down).toFixed(3)}`); + } + }); + + test('downdraft 0 gives a perfectly horizontal wind', () => { + const def = JSON.parse(JSON.stringify(storms.storm_02_wildnight)); + def.gusts.downdraft = 0; + const f = createWindField(def); + const out = { x: 0, y: 0, z: 0 }; + for (let t = 0; t <= f.duration; t += 0.05) { + f.vecAt(2, -1, t, out); + assert(out.y === 0, `y=${out.y} at t=${t.toFixed(2)} with downdraft 0 — the opt-out leaks`); + } + }); + + test('downdraft does not re-time the storm', () => { + // The vertical draws from its own RNG stream precisely so that adding or + // tuning it can't shift gust times or powers. Lane A hand-drove storm_02 and + // watched the carabiner blow at t=45.4 and p2 cascade at t=56; a downdraft + // tweak silently moving those would be a nasty way to lose an afternoon. + const base = storms.storm_02_wildnight; + const a = createWindField(base); + for (const dd of [0, 0.1, 0.25, 0.5, 1]) { + const d = JSON.parse(JSON.stringify(base)); + d.gusts.downdraft = dd; + const b = createWindField(d); + assert(a.gusts.length === b.gusts.length, `downdraft ${dd} changed the gust count`); + a.gusts.forEach((g, i) => { + assert(g.t0 === b.gusts[i].t0, + `downdraft ${dd} moved gust ${i} from t=${g.t0.toFixed(3)} to ${b.gusts[i].t0.toFixed(3)}`); + assert(g.pow === b.gusts[i].pow, `downdraft ${dd} changed gust ${i}'s power`); + }); + } + }); + + test('at a gust peak the downdraft is a real fraction of the horizontal', () => { + const f = createWindField(storms.storm_02_wildnight); + const out = { x: 0, y: 0, z: 0 }; + let bestRatio = 0, atT = 0; + for (let t = 0; t <= f.duration; t += DT) { + f.vecAt(0, 0, t, out); + const horiz = Math.hypot(out.x, out.z); + if (horiz < 1) continue; + const r = Math.abs(out.y) / horiz; + if (r > bestRatio) { bestRatio = r; atT = t; } + } + metrics['storm_02.peakVerticalRatio'] = +bestRatio.toFixed(3); + assert(bestRatio > 0.12, + `strongest downdraft is only ${(bestRatio * 100).toFixed(0)}% of the horizontal wind (t=${atT.toFixed(1)}) — a flat sail still shrugs`); + }); + + test('validator rejects a bad downdraft', () => { + for (const dd of [-0.1, 1.5, NaN, 'lots']) { + const d = JSON.parse(JSON.stringify(storms.storm_02_wildnight)); + d.gusts.downdraft = dd; + const { ok } = validateStorm(d, 'broken'); + assert(!ok, `validator ACCEPTED downdraft = ${dd}`); + } + }); + return { cases, metrics }; } diff --git a/web/world/js/weather.core.js b/web/world/js/weather.core.js index 6d4b4ed..43cb02c 100644 --- a/web/world/js/weather.core.js +++ b/web/world/js/weather.core.js @@ -130,17 +130,29 @@ function sampleAngleCurve(curve, t) { // ---------- gust timeline ---------- // Prototype: pow = 12 + rand*16 + 10*p, next = t + 5 + rand*7. Same shape, from JSON. +export const DEFAULT_DOWNDRAFT = 0.25; + export function buildGustTimeline(def, seed) { const g = def.gusts || {}; const rng = mulberry32(seed >>> 0); + // Vertical draws from its OWN stream, deliberately. Pulling it from `rng` + // would shift every subsequent (t0, pow) and silently re-time storms that are + // already tuned and hand-verified — A drove storm_02 and watched the carabiner + // blow at t=45.4 and cascade at t=56, one second after the change. Adding a + // downdraft shouldn't move that. + const rngV = mulberry32((seed ^ 0x0d0117) >>> 0); const minGap = g.minGap ?? 5, maxGap = g.maxGap ?? 12; + const downFrac = g.downdraft ?? DEFAULT_DOWNDRAFT; const out = []; let t = g.firstAt ?? 3; // hard cap: a malformed gap can't spin us forever while (t < def.duration && out.length < 512) { const p = def.duration > 0 ? t / def.duration : 0; const pow = (g.powBase ?? 12) + rng() * (g.powRand ?? 16) + (g.powRamp ?? 10) * p; - out.push({ t0: t, pow, rampAt: t + GUST.TELEGRAPH, endAt: t + GUST.TOTAL }); + // Not every gust slams down the same: some roll through nearly flat, some + // are a proper little downburst. 0.6–1.4× the storm's fraction. + const down = downFrac * (0.6 + rngV() * 0.8); + out.push({ t0: t, pow, down, rampAt: t + GUST.TELEGRAPH, endAt: t + GUST.TOTAL }); t += minGap + rng() * Math.max(0, maxGap - minGap); } return out; @@ -190,6 +202,26 @@ export function createWindField(def, opts = {}) { return sampleAngleCurve(def.dirCurve, t) + wAmp * Math.sin(t * wRate); } + /** + * Vertical wind, m/s. NEGATIVE = downward. Zero between gusts. + * + * A gust front is descending air, not just faster air. Without this the field + * is perfectly horizontal, and a horizontal sail is a free lunch: cloth + * pressure goes with dot(wind, normal), a flat panel's normal points at the + * sky, and the dot product is ~0 no matter how hard it blows. So the cheapest + * winning rig was "lie it flat and ignore the storm", which is the opposite of + * the game (SPRINT2 decision 3). A downdraft hits a flat panel square on. + */ + function gustVertical(t) { + let v = 0; + for (let i = 0; i < gusts.length; i++) { + const g = gusts[i]; + if (t <= g.t0) break; // sorted — nothing later is live + if (t < g.endAt) v -= gustEnvelope(t - g.t0, g.pow) * g.down; + } + return v; + } + // ---- noise drift ---- // The noise pattern rides downwind with the mean flow (Taylor's frozen // turbulence), so a gust visibly travels ACROSS the yard instead of blinking on @@ -278,7 +310,13 @@ export function createWindField(def, opts = {}) { }, get shelters() { return shelters; }, - /** Scalar wind speed (m/s) at a point. The cheap path — no allocation. */ + /** + * Scalar wind speed (m/s) at a point — HORIZONTAL only, which is what an + * anemometer reads and what the HUD, rain and grass want. The gust downdraft + * is deliberately not in here: a wind meter jumping because air is falling + * past it would read as a bug. Use vecAt/sample for the full 3D vector. + * The cheap path — no allocation. + */ speedAt(x, z, t) { const uni = uniformSpeed(t); const d = dirAt(t); @@ -289,16 +327,18 @@ export function createWindField(def, opts = {}) { dirAt, uniformSpeed, gustOnly, + gustVertical, /** Writes wind velocity (m/s) into out {x,y,z}. Ground plane is XZ, +Y up. */ vecAt(x, z, t, out) { const uni = uniformSpeed(t); const d = dirAt(t); const dirX = Math.cos(d), dirZ = Math.sin(d); - let s = uni * spatialFactor(x, z, t) * shelterFactor(x, z, dirX, dirZ); + const m = spatialFactor(x, z, t) * shelterFactor(x, z, dirX, dirZ); + let s = uni * m; if (s < 0) s = 0; out.x = dirX * s; - out.y = 0; // wind is horizontal; lift is the sail's job (Lane B) + out.y = gustVertical(t) * m; // gust fronts descend — see gustVertical() out.z = dirZ * s; return out; }, @@ -375,6 +415,10 @@ export function validateStorm(def, name = 'storm') { // Overlapping gusts stack, and a stacked telegraph is unreadable to the player. if (minGap < GUST.TOTAL) bad(`gusts.minGap (${minGap}) < gust length ${GUST.TOTAL}s — gusts would overlap`); if ((g.powBase ?? 12) < 0) bad('gusts.powBase must be >= 0'); + const dd = g.downdraft ?? DEFAULT_DOWNDRAFT; + if (!Number.isFinite(dd) || dd < 0 || dd > 1) { + bad(`gusts.downdraft must be 0..1 — the fraction of gust power that blows DOWN — got ${dd}`); + } } for (const e of def.events || []) {