Add habitable storm visual effect and ice landing videos

- New StormLayer renders purple cloud clusters with a seeded charge → strike → afterglow envelope in the upper sky, using sprite compositing (back/flash/front trios) rather than shaders
- Add `stormEnvelope` + `sstep01` to SystemEffectsMath.js; refactor NebulaAtmosphere's cloud shape into a shared `cloudAlpha` used by both `drawCloud` and the storm's flash texture
- Extend EmberField with optional per-spark twinkle (rate/depth) so habitable fireflies pulse while redDwarf embers stay steady
- Wire StormLayer create/update/destroy into GameScene alongside the other content effects
- Populate `types.habitable.effect` in systems.json with grade, void, particles, and storm blocks; update landing.json to use ice land/takeoff videos for slots 02 and 03
- Add 7 new test checks covering the storm envelope math, habitable data contract, bundle sanity, and facade apply(); bump live types from three to four

data/landing.json

@@ -64,8 +64,8 @@
     { "land": "rocky-land-02.mp4", "surface": "rocky-surface-02.mp4", "takeoff": "rocky-takeoff-02.mp4", "shop": "rocky-shop-02.mp4" },
     { "land": "rocky-land-03.mp4", "surface": "rocky-surface-03.mp4", "takeoff": "rocky-takeoff-03.mp4", "shop": "rocky-shop-03.mp4" },
     { "land": "ice-land-01.mp4", "surface": "rocky-surface-01.mp4", "takeoff": "ice-takeoff-01.mp4", "shop": "rocky-shop-01.mp4" },
-    { "land": "rocky-land-02.mp4", "surface": "rocky-surface-02.mp4", "takeoff": "rocky-takeoff-02.mp4", "shop": "rocky-shop-02.mp4" },
-    { "land": "rocky-land-03.mp4", "surface": "rocky-surface-03.mp4", "takeoff": "rocky-takeoff-03.mp4", "shop": "rocky-shop-03.mp4" }
+    { "land": "ice-land-02.mp4", "surface": "rocky-surface-02.mp4", "takeoff": "ice-takeoff-02.mp4", "shop": "rocky-shop-02.mp4" },
+    { "land": "ice-land-03.mp4", "surface": "rocky-surface-03.mp4", "takeoff": "ice-takeoff-03.mp4", "shop": "rocky-shop-03.mp4" }
   ],
 
   "stationVideos": [

data/systems.json

@@ -91,7 +91,22 @@
       "description": "Temperate, well-lit, and quietly crowded with life. Rare.",
       "theme": { "color": "#7ce8a4" },
       "distribution": { "weight": 10 },
-      "effect": {},
+      "effect": {
+        "grade": { "tint": "#bfe8c8", "amount": 0.10, "saturation": 1.05, "brightness": 1.02, "lift": { "amount": 0.14, "color": "#7ce8a4" } },
+        "void": { "base": "#0a1210", "alpha": 1.0, "grain": 5, "blobs": 5, "scale": [0.2, 0.5] },
+        "particles": { "count": 24, "size": [2, 4], "alpha": [0.35, 0.8], "parallax": [0.2, 0.45], "speed": [4, 12], "color": "#cdeb8b", "blend": "add", "twinkle": { "rate": [0.4, 1.1], "depth": [0.4, 0.85] } },
+        "storm": {
+          "clusters": 3,
+          "back": "#6b5fa8",
+          "front": "#191430",
+          "flash": "#cfd6ff",
+          "size": [420, 640],
+          "parallax": [0.05, 0.10],
+          "alpha": { "back": [0.30, 0.42], "front": [0.38, 0.50] },
+          "cycle": { "interval": [10, 16], "charge": 0.45, "flicker": 0.55 },
+          "flashStrength": 0.9
+        }
+      },
       "attributes": {
         "star": {
           "classes": { "G": 70, "K": 30 },

dev/system-effects.test.mjs

@@ -12,10 +12,13 @@
  *     (brightness → saturation → tint → split → flash) is exact and
  *     identity when the grade is empty;
  *   - the DATA CONTRACT (data/systems.json): every type carries an
- *     `effect` block; nebula/redDwarf/binary are live (kind "ripple");
+ *     `effect` block; nebula/redDwarf/binary/habitable are live;
  *     the redDwarf bundle has a flare + grade + particles; the binary
- *     bundle has two centers + orbit + a split grade + a wanderer; padding
- *     covers the worst-case displacement (amplitude × flare boost ×
+ *     bundle has a split grade + a two-light lift + a breath + a wanderer;
+ *     the habitable bundle has a green grade + void + twinkling fireflies +
+ *     a storm; the storm envelope (charge → strike → afterglow) is quiet
+ *     mid-cycle, peaks at the strike, strobes and decays; padding covers
+ *     the worst-case displacement (amplitude × flare boost ×
  *     centers × width);
  *   - the DEMO PICKER (js/galaxy/FxSystems.js): richest system of the
  *     requested type wins, ties fall to roster order, missing type => null;
@@ -133,6 +136,47 @@ check('orbit: advancing time moves the pair (a full lap per period)', (() => {
     (approx(t36.cx0, t0.cx0, 1e-6) && approx(t36.cy0, t0.cy0, 1e-6))
   );
 })());
+
+// --- The habitable storm envelope (charge → strike → afterglow) -----------
+check('storm: quiet mid-cycle (no flash, charge settled)', (() => {
+  // 25% into a 12s cycle — before the charge window (last 45%) begins
+  const e = M.stormEnvelope(3000, 12, 0.55, 0, 0.45);
+  return e.flash === 0 && e.charge === 0;
+})());
+check('storm: the charge rises smoothly to 1 at the strike', (() => {
+  const at = (frac) => M.stormEnvelope(frac * 12 * 1000, 12, 0.55, 0, 0.45).charge;
+  const cEarly = at(0.5); // before the charge window (1-0.45=0.55)
+  const cMid = at(0.75); // mid-rise
+  const cLate = at(0.95); // near the strike
+  const cPeak = at(0.999); // just before the strike (the light is about to be released)
+  const cAfter = M.stormEnvelope(100, 12, 0.55, 0, 0.45).charge; // just after — spent
+  return cEarly === 0 && cMid > cEarly && cLate > cMid && cPeak > 0.99 && cAfter === 0;
+})());
+check('storm: the strike flashes ~1, then strobes (a rebound burst) and decays', (() => {
+  const W = 0.55;
+  const at = (dtSec) => M.stormEnvelope(12 * 1000 + dtSec * 1000, 12, W, 0, 0.45).flash;
+  return (
+    at(0) > 0.95 && // the primary burst
+    at(0.45 * W) > 0.4 && // the rebound burst is clearly present
+    at(2 * W) < 0.1 && // the afterglow has mostly faded
+    at(4 * W) < 0.03 && // …and is gone
+    M.stormEnvelope(12 * 1000 - 1000, 12, W, 0, 0.45).flash === 0 // nothing BEFORE the strike
+  );
+})());
+check('storm: bounded, deterministic, phase-shifted, no NaN across a sweep', (() => {
+  const sweep = () => {
+    for (let ms = 0; ms < 2 * 12 * 1000; ms += 7) {
+      const e = M.stormEnvelope(ms, 12, 0.55, 3.7, 0.45);
+      if (!Number.isFinite(e.charge) || !Number.isFinite(e.flash)) return false;
+      if (e.charge < 0 || e.charge > 1 || e.flash < 0 || e.flash > 1) return false;
+    }
+    return true;
+  };
+  const a = M.stormEnvelope(1000, 12, 0.55, 1.0, 0.45);
+  const b = M.stormEnvelope(1000, 12, 0.55, 1.0, 0.45);
+  const c = M.stormEnvelope(1000, 12, 0.55, 6.0, 0.45);
+  return sweep() && a.charge === b.charge && a.flash === b.flash && (a.charge !== c.charge || a.flash !== c.flash);
+})());
 check('hexToRgb01: parses #rrggbb and bad input falls to white', (() => {
   const w = M.hexToRgb01('#ffffff');
   const b = M.hexToRgb01('#0000ff');
@@ -203,13 +247,13 @@ check('grade: the shadow lift integrates into gradeColor (red void)', (() => {
 
 const types = config.section('systems.types', {});
 const typeIds = Object.keys(types);
-const LIVE = ['nebula', 'redDwarf', 'binary'];
+const LIVE = ['nebula', 'redDwarf', 'binary', 'habitable'];
 const num_ = (v) => typeof v === 'number' && Number.isFinite(v);
 check('all six archetypes are present', typeIds.length === 6 && ['main', 'redDwarf', 'binary', 'habitable', 'nebula', 'void'].every((t) => typeIds.includes(t)));
 check('every type carries an effect block (data-driven by rule)', typeIds.every((t) => types[t].effect && typeof types[t].effect === 'object'));
-check('the three live types wear sub-effect blocks; the rest render untouched', (() => {
+check('the four live types wear sub-effect blocks; the rest render untouched', (() => {
   const live = LIVE.every((t) => Object.keys(types[t].effect).length > 0);
-  const still = ['main', 'habitable', 'void'].every((t) => Object.keys(types[t].effect || {}).length === 0);
+  const still = ['main', 'void'].every((t) => Object.keys(types[t].effect || {}).length === 0);
   return live && still;
 })());
 check('nebula: a steady ripple, nothing else', (() => {
@@ -241,6 +285,18 @@ check('binary: a two-color split grade + a two-light void lift + a breath + a wa
     Array.isArray(w.coreSize) && Array.isArray(w.haloSize)
   );
 })());
+check('habitable: a lush grade + a green void + twinkling fireflies + a purple storm, and NO ripple', (() => {
+  const e = types.habitable.effect;
+  return (
+    e.ripple == null &&
+    !!e.grade && typeof e.grade.tint === 'string' && e.grade.lift?.color === '#7ce8a4' && // a green-tinged well-lit wash
+    e.grade.split == null && e.breath == null && // the storm breathes instead
+    typeof e.void?.base === 'string' && // the forest-night dark
+    !!e.particles && typeof e.particles.color === 'string' && !!e.particles.twinkle && // the fireflies (they pulse)
+    !!e.storm && typeof e.storm.back === 'string' && typeof e.storm.front === 'string' && // the purple storm
+    typeof e.storm.flash === 'string' && e.storm.back !== e.storm.front
+  );
+})());
 check('every ripple bundle has sane numbers + padding covering the worst case', (() => {
   const maxDim = Math.max(1280, 720);
   return ['nebula', 'redDwarf'].every((t) => {
@@ -292,6 +348,28 @@ check('binary bundle: a two-color split grade + a two-light void glow + a slow b
     Array.isArray(w.coreSize) && w.coreSize[1] >= 80 && Array.isArray(w.haloSize) && w.haloSize[1] >= 250 // present, not a smudge
   );
 })());
+check('habitable bundle: a gentle well-lit grade, a forest-night void, pulsing fireflies, and a storm that strikes', (() => {
+  const e = types.habitable.effect;
+  const g = e.grade ?? {};
+  const p = e.particles ?? {};
+  const st = e.storm ?? {};
+  const n = (v) => typeof v === 'number' && Number.isFinite(v);
+  return (
+    n(g.amount) && g.amount > 0 && g.amount < 0.2 && // a wash, not a wall
+    n(g.brightness) && g.brightness > 1 && n(g.saturation) && g.saturation > 1 && // the only type that gets more light
+    n(g.lift?.amount) && g.lift.amount > 0 && typeof g.lift.color === 'string' &&
+    typeof e.void?.base === 'string' && n(e.void?.grain) && e.void.grain >= 0 &&
+    n(p.count) && p.count >= 10 && typeof p.color === 'string' && p.blend === 'add' &&
+    Array.isArray(p.twinkle?.rate) && p.twinkle.rate[1] < 2 && // a slow blink, not a strobe
+    Array.isArray(p.twinkle?.depth) && p.twinkle.depth[1] < 1 &&
+    n(st.clusters) && st.clusters >= 2 &&
+    Array.isArray(st.size) && st.size[0] >= 300 && // real clouds, not mist
+    Array.isArray(st.cycle?.interval) && st.cycle.interval[0] >= 6 && // a patient storm
+    n(st.cycle?.flicker) && st.cycle.flicker > 0 &&
+    n(st.cycle?.charge) && st.cycle.charge > 0 && st.cycle.charge < 1 &&
+    n(st.flashStrength) && st.flashStrength > 0 && st.flashStrength <= 1
+  );
+})());
 
 // --- The demo picker (js/galaxy/FxSystems.js) -------------------------------
 
@@ -476,6 +554,22 @@ check('facade: update() breathes the binary lights over time', (() => {
   fx.update((grade.breathPeriod * 1000) / 4);
   return grade.uBreath !== b0 && Math.abs(grade.uBreath) <= grade.breathDepth;
 })());
+check('facade: apply(habitable) → a well-lit GREEN grade (single-hue lift, no split, no breath, no ripple)', (() => {
+  fakeCamMain.filters.internal.list.length = 0;
+  const active = fx.apply('habitable');
+  const list = fakeCamMain.filters.internal.list;
+  const ripple = list.find((c) => c.renderNode === SE.RIPPLE_NODE);
+  const grade = list.find((c) => c.renderNode === SE.GRADE_NODE);
+  return (
+    active === true && fx.kind === 'grade' && list.length === 1 &&
+    !ripple &&
+    grade && grade.uTintAmt > 0 && grade.uBright > 1 && grade.uSat > 1 && // well-lit + lush
+    grade.uLiftAmt > 0 && // the green shadow lift
+    grade.uLiftG > grade.uLiftR && grade.uLiftG > grade.uLiftB && // it is green
+    grade.uLift2R === grade.uLiftR && grade.uLift2G === grade.uLiftG && grade.uLift2B === grade.uLiftB && // single-hue (no second light)
+    (grade.uSplitMix === 0 || grade.uSplitMix === undefined) && grade.breathPeriod === 0 && grade.uBreath === 0
+  );
+})());
 check('facade: apply() twice replaces (no duplicate filters)', (() => {
   fx.apply('redDwarf');
   return fakeCamMain.filters.internal.list.length === 2;

docs/PROJECT_NOTES.md

@@ -1112,7 +1112,9 @@ The player holds a REPUTATION (standing) on each planet and space station:
 - A system's visual character is a **bundle of sub-effects** configured per
   archetype in `data/systems.json → types.<type>.effect`. Each sub-effect is
   an OPTIONAL block; a type wears exactly what it lists (an empty `{}` = no
-  effect). Three archetypes are live today; the rest render untouched:
+  effect). Four archetypes are live today; `main` and `void` render
+  untouched on purpose (plain is the control group — the universe must not
+  all look special):
   - **nebula** — the RIPPLE (1 center, screen anchor): concentric rings,
     the light unsettled.
   - **redDwarf** — a SUPER-subtle RIPPLE (1 center, star anchor; the base
@@ -1128,6 +1130,15 @@ The player holds a REPUTATION (standing) on each planet and space station:
     wandering companion star (content). NO ripple — two stars, one steady
     light. The two-color void needs a neutral content base to paint on (the
     clear color bypasses the filter) — see `void` below.
+  - **habitable** — an ELECTRIFIED STORM in the upper sky (2–3 purple
+    cloud clusters, each a back/flash/front trio; per-cluster lightning
+    strikes on a seeded cycle — charge rises, the core ignites, a rebound
+    flicker, a decaying afterglow; the strike's 3D is pure sprite compositing
+    — see the storm section below) + a FOREST-NIGHT void base (deep
+    green-black, so the darkness feels vegetative) + twinkling FIREFLIES
+    (slow green motes with a `twinkle` pulse — the ember field's optional
+    twinkle) + a near-neutral GREEN grade (the storm owns the purple; the
+    green lives in the fireflies and the void, not a tint over everything).
   The star itself is invisible flavor; the shimmer / glow / wander is its
   character.
 - Two kinds of sub-effect:
@@ -1146,19 +1157,27 @@ The player holds a REPUTATION (standing) on each planet and space station:
     both filters read, so the wave and the light flash as one.
   - **Content** (world-space sprites, Canvas-safe, behind the art):
     `haze` (redDwarf red haze over the void → `js/visuals/RedHaze.js`, depth
-    −1, BEHIND the stars), `void` (binary's NEUTRAL dark+grit void base →
-    `js/visuals/VoidBase.js`, depth −1 — the surface the two-light lift and
-    breath paint on, since the clear color bypasses the filter),
-    `particles` (redDwarf ember dust → `js/visuals/EmberField.js`), and
-    `wanderer` (binary companion star → `js/visuals/WandererStar.js`).
+    −1, BEHIND the stars), `void` (binary's NEUTRAL dark+grit void base /
+    habitable's FOREST-NIGHT green-black base → `js/visuals/VoidBase.js`,
+    depth −1 — the surface the lift/haze paint on, since the clear color
+    bypasses the filter),
+    `particles` (redDwarf ember dust / habitable twinkling fireflies →
+    `js/visuals/EmberField.js`; the optional `twinkle: {rate,depth}` gives
+    each mote a slow sine pulse, and no twinkle config = steady embers),
+    `wanderer` (binary companion star → `js/visuals/WandererStar.js`), and
+    `storm` (habitable's purple storm → `js/visuals/StormLayer.js` — a SKY
+    DOME: the clusters are anchored to the camera view with near-zero
+    parallax (0.05–0.10) so they stay overhead while the world flies past,
+    wrapping into a visible sky band).
 - Files: `js/visuals/SystemEffects.js` (ripple + grade filters + facade),
-  `js/visuals/SystemEffectsMath.js` (pure UV / flare / orbit / grade / lift
-  math), `js/visuals/UiCameras.js` (the UI camera split),
+  `js/visuals/SystemEffectsMath.js` (pure UV / flare / orbit / grade / lift /
+  storm-envelope math), `js/visuals/UiCameras.js` (the UI camera split),
   `js/visuals/RedHaze.js` (the gritty red haze), `js/visuals/VoidBase.js`
-  (the binary's neutral void base), `js/visuals/EmberField.js` (ember dust),
-  `js/visuals/WandererStar.js` (companion star),
+  (the neutral void base), `js/visuals/EmberField.js` (ember dust +
+  twinkle), `js/visuals/WandererStar.js` (companion star),
+  `js/visuals/StormLayer.js` (the habitable storm),
   `js/galaxy/FxSystems.js` (demo system picker),
-  `dev/system-effects.test.mjs` (59 checks, bare Node).
+  `dev/system-effects.test.mjs` (66 checks, bare Node).
 - **How the filters draw (Phaser 4.2.1):** each filter is a
   `Phaser.Filters.Controller` on `cameras.main`'s `filters.internal` list —
   when any internal filter is active the camera pass auto-composites (FBO +
@@ -1261,6 +1280,55 @@ The player holds a REPUTATION (standing) on each planet and space station:
   nebula (a different seed → a different gas color) — fly around and
   judge the look.
 
+## Habitable storm — lightning in the upper sky (content, Canvas-safe)
+
+- The habitable's signature: a few big PURPLE CLOUD CLUSTERS overhead that
+  periodically LIGHT UP — charge builds (the clouds brighten over the last
+  ~45% of the cycle), the core ignites in a white-lavender FLASH with a
+  quick rebound flicker, then the afterglow decays. Different clusters
+  strike on different seeds, so the sky is never a synchronized strobe —
+  it's a weather system. The narrative is Miller–Urey: life started in
+  lightning.
+- **The 3D is sprite compositing, not shaders.** Each cluster is three
+  sprites at depths 3.0/3.1/3.2 (above the starfield, below planets/ship):
+  - a BACK cloud (violet, soft — the light source seen through),
+  - a FLASH (additive, cloud-shaped with a HOT RADIAL CORE — `drawFlash`
+    = the shared `cloudAlpha` fbm shape ∪ a bright core, so a strike reads
+    as the cloud igniting from within),
+  - a FRONT cloud (dark indigo, fbm holes) that silhouettes over the flash —
+    the light finds the gaps and wraps the cloud's edge (the additive bleed
+    past the dark rim). The offsets are loose enough that the core survives
+    the overlap; the density does the rest.
+- **The storm is a SKY DOME, not a world-space object.** The clusters are
+  anchored to the camera view (view-space home + tiny drift + wrap into a
+  visible sky band, the same model as the wanderer star and starfield) with
+  near-zero parallax (0.05–0.10): they stay overhead while the world flies
+  past. (A first cut used wide world-space margins like the starfield and
+  the clouds drifted off-screen with 3 big sprites — the sky-anchor is the
+  fix.)
+- **The envelope is pure + tested:** `stormEnvelope(now, interval, strike,
+  phase, chargeWindow)` in `SystemEffectsMath.js` → `{charge, flash}`
+  (both 0..1). Charge = a smoothstep ramp in the last `chargeWindow`
+  fraction of the cycle (resets at the strike); flash = a Gaussian primary
+  burst + rebound + third crack + an exponential afterglow, clipped to
+  three strike-durations so the sky is fully quiet between storms.
+- **Alpha model:** back = base × (0.7 + 0.5·charge + 0.3·flash) (the build
+  is visible); flash = env.flash × flashStrength (ADD); front = base ×
+  (0.8 + 0.3·charge) (it darkens as the charge builds).
+- **Files:** `js/visuals/StormLayer.js` (clusters, sky anchor, per-frame
+  envelope → alphas), `js/visuals/SystemEffectsMath.js` (`stormEnvelope`,
+  `sstep01`), `js/visuals/NebulaAtmosphere.js` (`cloudAlpha` + `drawCloud`
+  — the shared cloud shape; `drawFlash` in StormLayer adds the hot core),
+  `data/systems.json → types.habitable.effect` (the whole package),
+  `js/scenes/GameScene.js` (create/update/destroy wiring).
+- **Tuning is a JSON edit** (`types.habitable.effect.storm`): `clusters`,
+  `back/front/flash` colors, `size`, `parallax` (keep it sky-slow), `alpha`
+  (keep the clouds a presence, not a ceiling), `cycle.interval` (calm
+  weather = 10–16 s), `cycle.charge` (how long the build lasts),
+  `cycle.flicker` (strike + rebound length), `flashStrength`.
+- **See it:** `dev/test-game.html?fx=habitable&seed=<seed>` — fly for a
+  minute; strikes land every ~10–16 s per cluster, staggered.
+
 ## Roadmap (working list, intentionally rough)
 
 - [x] v0.1 foundation — menu → New Game → click-to-fly ship

js/scenes/GameScene.js

@@ -23,6 +23,7 @@ import { EmberField } from '../visuals/EmberField.js';
 import { WandererStar } from '../visuals/WandererStar.js';
 import { RedHaze } from '../visuals/RedHaze.js';
 import { VoidBase } from '../visuals/VoidBase.js';
+import { StormLayer } from '../visuals/StormLayer.js';
 import { SystemEffects } from '../visuals/SystemEffects.js';
 import { assignUi, assignWorld } from '../visuals/UiCameras.js';
 import { pickFxSystem } from '../galaxy/FxSystems.js';
@@ -632,6 +633,10 @@ export class GameScene extends Phaser.Scene {
       this.voidBase = new VoidBase(this, _fx.void, this.systemContent?.fx ?? {});
       this.voidBase.create();
     }
+    if (_fx?.storm) {
+      this.storm = new StormLayer(this, _fx.storm, this.systemContent?.fx ?? {});
+      this.storm.create();
+    }
     if (_fx?.particles) {
       this.embers = new EmberField(this, _fx.particles.color, _fx.particles, this.systemContent?.fx ?? {});
       this.embers.create();
@@ -1696,6 +1701,7 @@ export class GameScene extends Phaser.Scene {
     this.nebula?.update(); // the gas: parallax + slow self-swirl
     this.haze?.update(_time, delta); // redDwarf red haze: follow the camera
     this.voidBase?.update(_time, delta); // binary void base: follow the camera
+    this.storm?.update(_time, delta); // habitable storm: parallax + charge/strike/afterglow
     this.embers?.update(_time, delta); // redDwarf ember dust: drift + parallax
     this.wanderer?.update(_time, delta); // binary companion star: slow wander
     this.tetherField.tick(_time, delta); // glitch/pulse lifecycle
@@ -4308,6 +4314,7 @@ export class GameScene extends Phaser.Scene {
     this.nebula?.destroy();
     this.haze?.destroy();
     this.voidBase?.destroy();
+    this.storm?.destroy();
     this.embers?.destroy();
     this.wanderer?.destroy();
     this.compass?.destroy();

js/visuals/EmberField.js

@@ -71,8 +71,14 @@ export class EmberField {
       alpha = [0.4, 0.9],
       parallax = [0.25, 0.5],
       speed = [8, 25],
+      twinkle = null,
     } = this.cfg;
 
+    // Optional twinkle (the habitable fireflies): each spark's alpha pulses
+    // on its own phase — depth 0 = steady (redDwarf embers, unchanged).
+    const twRate = twinkle?.rate ?? null;
+    const twDepth = twinkle?.depth ?? null;
+
     const texKey = canvasTexture(scene, 'fx-ember-spark', 32, 32, (ctx) => drawSpark(ctx, 32));
     const w = scene.scale.width;
     const h = scene.scale.height;
@@ -99,11 +105,12 @@ export class EmberField {
       const by = top + rand() * (h + 2 * MARGIN);
       const ang = rand() * Math.PI * 2;
       const spd = range(speed[0], speed[1]);
+      const baseAlpha = range(alpha[0], alpha[1]);
       const sp = scene.add
         .image(bx, by, texKey)
         .setDepth(DEPTH)
         .setTint(this.color)
-        .setAlpha(range(alpha[0], alpha[1]))
+        .setAlpha(baseAlpha)
         .setBlendMode(Phaser.BlendModes.ADD);
       const sz = range(size[0], size[1]);
       sp.setScale(sz / 16); // 32px texture, scale to ~size px
@@ -112,6 +119,10 @@ export class EmberField {
         vx: Math.cos(ang) * spd,
         vy: Math.sin(ang) * spd,
         p: range(parallax[0], parallax[1]),
+        baseAlpha,
+        twRate: twRate ? range(twRate[0], twRate[1]) : 0,
+        twDepth: twDepth ? range(twDepth[0], twDepth[1]) : 0,
+        twPhase: rand() * Math.PI * 2,
       });
     }
     this.lastScrollX = cam.scrollX;
@@ -143,6 +154,13 @@ export class EmberField {
       // Keep the field full: wrap into the current camera window.
       e.sp.x = wrapIn(e.sp.x, left, spanX);
       e.sp.y = wrapIn(e.sp.y, top, spanY);
+      // Twinkle (optional): the alpha pulses on its own phase — a firefly
+      // blinking in the grass, not a steady spark (depth 0 = steady).
+      if (e.twDepth > 0) {
+        const t = (nowMs || 0) / 1000;
+        const wave = 0.5 * (1 + Math.sin(t * Math.PI * 2 * e.twRate + e.twPhase));
+        e.sp.alpha = e.baseAlpha * (1 - e.twDepth + e.twDepth * wave);
+      }
     }
   }
 

js/visuals/NebulaAtmosphere.js

@@ -163,21 +163,17 @@ export class NebulaAtmosphere {
 // ---------------------------------------------------------------------------
 
 /**
- * Paint one soft cloud into a square canvas: value-noise fbm for the
- * internal structure, multiplied by a wide RADIAL falloff so the puff has
- * no perceptible silhouette — it is fully transparent by the inscribed
- * circle and dissolves gradually out, so no border or corner reads as a
- * hard edge. White RGB; the alpha channel carries the density (the
- * sprite's tint sets the color).
+ * Per-pixel cloud ALPHA (0..1) for a w×h canvas: value-noise fbm for the
+ * internal structure, multiplied by a wide radial falloff so the puff has
+ * no perceptible silhouette — fully transparent by the inscribed circle,
+ * dissolving gently out. (The single source of the cloud shape; both
+ * drawCloud and the storm's flash use it.)
  */
-export function drawCloud(ctx, w, h, tex, seed = 1337) {
+export function cloudAlpha(w, h, tex, seed = 1337) {
   const octaves = Math.max(1, Math.round(tex.octaves ?? 4));
   const persistence = clamp01(tex.persistence ?? 0.55);
-
-  const img = ctx.createImageData(w, h);
-  const d = img.data;
   const FREQ = 6; // base noise cells across the sprite (fewer, larger = smoother gas)
-
+  const out = new Float32Array(w * h);
   for (let y = 0; y < h; y++) {
     const v = y / h;
     for (let x = 0; x < w; x++) {
@@ -204,14 +200,27 @@ export function drawCloud(ctx, w, h, tex, seed = 1337) {
       // Gentle internal structure (fbm) — wispy density, not speckled dust.
       const structure = smoothstep(0.30, 0.80, n);
 
-      const a = radial * structure;
-      const idx = (y * w + x) * 4;
-      d[idx] = 255;
-      d[idx + 1] = 255;
-      d[idx + 2] = 255;
-      d[idx + 3] = Math.round(a * 255);
+      out[y * w + x] = radial * structure;
     }
   }
+  return out;
+}
+
+/**
+ * Paint one soft cloud into a square canvas (see cloudAlpha). White RGB;
+ * the alpha channel carries the density (the sprite's tint sets the color).
+ */
+export function drawCloud(ctx, w, h, tex, seed = 1337) {
+  const a = cloudAlpha(w, h, tex, seed);
+  const img = ctx.createImageData(w, h);
+  const d = img.data;
+  for (let i = 0; i < w * h; i++) {
+    const idx = i * 4;
+    d[idx] = 255;
+    d[idx + 1] = 255;
+    d[idx + 2] = 255;
+    d[idx + 3] = Math.round(a[i] * 255);
+  }
   ctx.putImageData(img, 0, 0);
 }
 

js/visuals/StormLayer.js

@@ -0,0 +1,284 @@
+/**
+ * StormLayer — the habitable system's electrified storm.
+ *
+ * WHY IT EXISTS: "Temperate, well-lit, and quietly crowded with life." —
+ * and life started in lightning (Miller–Urey). So a habitable system
+ * carries a slow PURPLE STORM: compact cloud clusters that gather charge,
+ * strike in a rapid flicker, and settle into a soft afterglow — the
+ * weather that seeded the worlds below.
+ *
+ * THE 3-D TRICK (three sprites per cluster, in depth order):
+ *   1. BACK   (depth 3.0) — the cloud body (fbm texture, purple tint), dim;
+ *                          brightens as the charge builds and on the strike.
+ *   2. FLASH  (depth 3.1) — the SAME kind of cloud shape (a related fbm
+ *                          texture), white-lavender, ADDITIVE, alpha 0 at
+ *                          rest. Because the flash is CLOUD-SHAPED (not a
+ *                          radial glow), it reads as the cloud igniting
+ *                          from within; the additive bleed past the edges
+ *                          is the light wrapping the silhouette.
+ *   3. FRONT  (depth 3.2) — a DIFFERENT, larger, darker cloud (indigo,
+ *                          normal blend). Its fbm holes let light leak
+ *                          through in a fractal pattern while the solid
+ *                          parts stay dark — DARK OVER BRIGHT is the
+ *                          silhouette that sells the depth: "dark clouds
+ *                          overlaying the brightness".
+ *
+ * Plain sprites composited in depth order — NO shaders, Canvas-safe, and
+ * it can never touch the HUD (world-space content, like the starfield).
+ * The storm is a SKY: anchored to the camera view (the wanderer model)
+ * with near-zero parallax — it stays overhead while the world flies past.
+ * *
+ * Timing is PURE and Node-tested (SystemEffectsMath.stormEnvelope):
+ * charge (a slow rise) → strike (a strobe of bursts) → afterglow (decay).
+ * Each cluster gets its own seeded interval + phase, so the strikes are
+ * staggered — the sky flickers from different places, like weather.
+ *
+ * Config: data/systems.json → types.habitable.effect.storm.
+ */
+import Phaser from '../vendor/phaser.js';
+import { toColor } from '../utils/Color.js';
+import { canvasTexture } from '../utils/Textures.js';
+import { drawCloud, cloudAlpha } from './NebulaAtmosphere.js';
+import { stormEnvelope } from './SystemEffectsMath.js';
+import { assignWorld } from './UiCameras.js';
+
+const MARGIN_X = 0.15; // fraction of view width a cluster may hang over an edge (wide clouds)
+const DEPTH_BACK = 3.0;
+const DEPTH_FLASH = 3.1;
+const DEPTH_FRONT = 3.2;
+const SKY = { x: 0.10, y: 0.08, w: 0.80, h: 0.34 }; // home band: upper view (fractions)
+const BAND_Y = { top: 0.03, bottom: 0.58 }; // wrap band: strictly inside the view (fractions)
+
+/** A seeded 32-bit PRNG (mulberry32) — stable cloud layout per cluster. */
+function makeRng(seedNum) {
+  let a = (seedNum >>> 0) || 0x9e3779b9;
+  return () => {
+    a |= 0; a = (a + 0x6d2b79f5) | 0;
+    let t = Math.imul(a ^ (a >>> 15), 1 | a);
+    t = (t + Math.imul(t ^ (a >>> 7), 61 | t)) ^ t;
+    return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
+  };
+}
+
+/** Maps any coordinate into [left, left + span) — safe for huge deltas. */
+function wrapIn(v, left, span) {
+  return left + ((((v - left) % span) + span) % span);
+}
+
+function normRange(range, fallback) {
+  if (Array.isArray(range) && range.length === 2 && range.every((n) => typeof n === 'number')) {
+    return [Math.min(range[0], range[1]), Math.max(range[0], range[1])];
+  }
+  return fallback;
+}
+
+/** Paints the LIGHTNING: the cloud shape (shared fbm) plus a HOT RADIAL
+ * CORE at the centre — so a strike reads as the cloud igniting from
+ * within, bright at the heart and melting out through the cloud body.
+ * White RGB; the alpha channel carries the intensity. */
+function drawFlash(ctx, w, h, tex, seed) {
+  const base = cloudAlpha(w, h, tex, seed);
+  const img = ctx.createImageData(w, h);
+  const d = img.data;
+  for (let y = 0; y < h; y++) {
+    const v = y / h - 0.5;
+    for (let x = 0; x < w; x++) {
+      const i = y * w + x;
+      const u = x / w - 0.5;
+      const r = Math.hypot(u, v) * 2; // 0 centre … 1 inscribed edge
+      const core = r < 0.72 ? Math.pow(1 - r / 0.72, 1.5) : 0;
+      const a = Math.min(1, Math.max(base[i], core));
+      const idx = i * 4;
+      d[idx] = 255;
+      d[idx + 1] = 255;
+      d[idx + 2] = 255;
+      d[idx + 3] = Math.round(a * 255);
+    }
+  }
+  ctx.putImageData(img, 0, 0);
+}
+
+/**
+ * The storm layer (2–3 cloud clusters, each a back / flash / front trio).
+ *
+ * @param {object} scene Phaser scene (add / camera / scale / textures)
+ * @param {object} cfg data/systems.json → effect.storm
+ * @param {{phase?:number, angle?:number, drift?:number}} fx per-system seeded 0..1 variation
+ */
+export class StormLayer {
+  constructor(scene, cfg, fx = {}) {
+    this.scene = scene;
+    this.cfg = cfg ?? {};
+    this.fx = fx ?? {};
+    this.clusters = [];
+    this.lastScrollX = 0;
+    this.lastScrollY = 0;
+  }
+
+  /** Build the cloud textures + one back/flash/front trio per cluster (idempotent). */
+  create() {
+    if (this.clusters.length) return;
+    const scene = this.scene;
+    const cam = scene.cameras.main;
+    const w = scene.scale.width;
+    const h = scene.scale.height;
+
+    const clusters = Math.max(1, Math.round(this.cfg.clusters ?? 3));
+    const [sMin, sMax] = normRange(this.cfg.size, [420, 640]);
+    const [pMin, pMax] = normRange(this.cfg.parallax, [0.03, 0.06]); // a SKY dome: barely drifts
+    const [baMin, baMax] = normRange(this.cfg.alpha?.back, [0.30, 0.42]);
+    const [faMin, faMax] = normRange(this.cfg.alpha?.front, [0.38, 0.50]);
+    const [iMin, iMax] = normRange(this.cfg.cycle?.interval, [10, 16]);
+    const strikeDur = Math.max(0.15, Number(this.cfg.cycle?.flicker) || 0.55);
+    const chargeWindow = Number(this.cfg.cycle?.charge) || 0.45;
+    const strength = Math.max(0, Number(this.cfg.flashStrength) || 0.9);
+
+    const backColor = toColor(this.cfg.back ?? '#6b5fa8', 0x6b5fa8);
+    const frontColor = toColor(this.cfg.front ?? '#191430', 0x191430);
+    const flashColor = toColor(this.cfg.flash ?? '#cfd6ff', 0xcfd6ff);
+
+    const TEX = 256;
+    // A few DISTINCT cloud shapes per role (different noise seeds) so the
+    // trio reads as a volume, not one image repeated. Cached by key; every
+    // habitable system reuses the set (only tint/layout/phase vary).
+    const tex = {
+      back: (i) => canvasTexture(scene, `fx-storm-back-${i}`, TEX, TEX, (ctx, tw, th) =>
+        drawCloud(ctx, tw, th, { octaves: 4, persistence: 0.55 }, 717 + i * 101)),
+      flash: (i) => canvasTexture(scene, `fx-storm-flash-${i}`, TEX, TEX, (ctx, tw, th) =>
+        drawFlash(ctx, tw, th, { octaves: 5, persistence: 0.6 }, 1009 + i * 101)),
+      front: (i) => canvasTexture(scene, `fx-storm-front-${i}`, TEX, TEX, (ctx, tw, th) =>
+        drawCloud(ctx, tw, th, { octaves: 4, persistence: 0.62 }, 1297 + i * 101)),
+    };
+
+    // Seeded per-cluster layout + rhythm (xorshift32 from the system fx,
+    // so the same system looks the same every run).
+    let s = (Math.imul(0x51ab1234, 2654435761) ^ Math.round((this.fx.phase ?? 0.5) * 1e9)) >>> 0;
+    const rand = () => {
+      s ^= s << 13; s >>>= 0;
+      s ^= s >> 17; s >>>= 0;
+      s ^= s << 5; s >>>= 0;
+      return (s >>> 0) / 4294967296;
+    };
+    const range = (a, b) => a + (b - a) * rand();
+
+    // Clusters live in the SKY band — the upper part of the view. Their
+    // home is stored in VIEW space (the wanderer model): each frame we add
+    // a camera-parallax drift and wrap back into the band, so the storm is
+    // always overhead no matter how far the ship flies. (Placing them in
+    // world space with a wide margin let them drift out of view — the old
+    // bug.)
+    for (let i = 0; i < clusters; i++) {
+      const S = range(sMin, sMax);
+      const homeX = (SKY.x + SKY.w * rand()) * w; // across the sky
+      const homeY = (SKY.y + SKY.h * rand()) * h; // upper half only
+      const p = range(pMin, pMax);
+      const interval = range(iMin, iMax);
+      const phase = rand() * interval; // staggered strikes (seeded)
+
+      const bx = (cam.scrollX ?? 0) + homeX;
+      const by = (cam.scrollY ?? 0) + homeY;
+
+      const back = scene.add.image(bx, by, tex.back(i))
+        .setDepth(DEPTH_BACK).setTint(backColor)
+        .setScale(S / TEX).setAlpha(baMin)
+        .setRotation(rand() * Math.PI * 2);
+      // The flash sits inside the cloud body, near-centre (the hot core is
+      // the strike — it must not be buried under the front cloud).
+      const flashOffX = (rand() - 0.5) * 0.08 * S;
+      const flashOffY = (rand() - 0.5) * 0.08 * S;
+      const flash = scene.add.image(bx + flashOffX, by + flashOffY, tex.flash(i))
+        .setDepth(DEPTH_FLASH).setTint(flashColor)
+        .setScale((0.85 * S) / TEX).setAlpha(0)
+        .setBlendMode(Phaser.BlendModes.ADD)
+        .setRotation(back.rotation + (rand() - 0.5) * 0.4);
+      // The dark front: larger, offset, OVER the flash — the silhouette.
+      // Loose offset so its fbm holes + edge let the flash read through
+      // (light wrapping the dark cloud), without burying the core.
+      const frontOffX = (rand() - 0.5) * 0.16 * S;
+      const frontOffY = (rand() - 0.5) * 0.14 * S;
+      const front = scene.add.image(bx + frontOffX, by + frontOffY, tex.front(i))
+        .setDepth(DEPTH_FRONT).setTint(frontColor)
+        .setScale((1.12 * S) / TEX).setAlpha(faMin)
+        .setRotation(back.rotation + (rand() - 0.5) * 0.3);
+
+      assignWorld(scene, back);
+      assignWorld(scene, flash);
+      assignWorld(scene, front);
+
+      this.clusters.push({
+        back, flash, front,
+        homeX, homeY, p,
+        flashOffX, flashOffY, frontOffX, frontOffY,
+        driftX: 0, driftY: 0, // accumulated parallax drift (view space)
+        interval, phase, strikeDur, chargeWindow, strength,
+        backBase: range(baMin, baMax),
+        frontBase: range(faMin, faMax),
+      });
+    }
+    this.lastScrollX = cam.scrollX;
+    this.lastScrollY = cam.scrollY;
+  }
+
+  /**
+   * Per-frame: anchor each trio to the sky band (home + parallax drift,
+   * wrapped into the band — the wanderer model), and drive the storm cycle
+   * (charge → strike → afterglow) on each trio's alphas.
+   */
+  update(nowMs, dtMs) {
+    if (!this.clusters.length) return;
+    const scene = this.scene;
+    const cam = scene.cameras.main;
+    const camX = cam.scrollX;
+    const camY = cam.scrollY;
+
+    const w = scene.scale.width;
+    const h = scene.scale.height;
+    const dx = camX - this.lastScrollX;
+    const dy = camY - this.lastScrollY;
+    this.lastScrollX = camX;
+    this.lastScrollY = camY;
+
+    // The sky band, in VIEW space: strictly inside the visible view (upper
+    // ~58%), so the trio is always overhead — no off-screen overhang. The
+    // wrap is done in view space (camera-independent), then converted to
+    // world space as camera + view offset — the wanderer model. (The storm
+    // is a SKY: it stays put while the world flies past; its near-zero
+    // parallax is the illusion of a dome around the system.)
+    const vx0 = -MARGIN_X * w;
+    const vx1 = w + MARGIN_X * w;
+    const vy0 = BAND_Y.top * h;
+    const vy1 = BAND_Y.bottom * h;
+
+    for (const c of this.clusters) {
+      // Parallax drift in view space (trails the camera at p), wrapped so
+      // the trio stays in the band.
+      c.driftX -= dx * c.p;
+      c.driftY -= dy * c.p;
+      const vx = wrapIn(c.homeX + c.driftX, vx0, vx1 - vx0);
+      const vy = wrapIn(c.homeY + c.driftY, vy0, vy1 - vy0);
+
+      c.back.x = camX + vx;
+      c.back.y = camY + vy;
+      c.flash.x = c.back.x + c.flashOffX;
+      c.flash.y = c.back.y + c.flashOffY;
+      c.front.x = c.back.x + c.frontOffX;
+      c.front.y = c.back.y + c.frontOffY;
+
+      // The storm cycle (pure, seeded, Node-tested).
+      const env = stormEnvelope(nowMs, c.interval, c.strikeDur, c.phase, c.chargeWindow);
+      c.back.setAlpha(c.backBase * (0.7 + 0.5 * env.charge + 0.3 * env.flash));
+      c.flash.setAlpha(env.flash * c.strength);
+      c.front.setAlpha(c.frontBase * (0.8 + 0.3 * env.charge));
+    }
+  }
+
+  /** Tear down. */
+  destroy() {
+    for (const c of this.clusters) {
+      c.back.destroy();
+      c.flash.destroy();
+      c.front.destroy();
+    }
+    this.clusters = [];
+  }
+}

js/visuals/SystemEffectsMath.js

@@ -117,6 +117,62 @@ export function orbitCenters(nowMs, periodSec, radius, phase = 0) {
   return { cx0: 0.5 + dx, cy0: 0.5 + dy, cx1: 0.5 - dx, cy1: 0.5 - dy };
 }
 
+/**
+ * A smoothstep on a 0..1 domain (mirrors the shader's).
+ */
+function sstep01(x) {
+  const t = Math.min(1, Math.max(0, x));
+  return t * t * (3 - 2 * t);
+}
+
+/**
+ * The HABITABLE storm's envelope at a moment: `{ charge, flash }`, both 0..1.
+ *
+ * The cycle (per cluster, seeded by its phase):
+ *   CHARGE  — a smooth rise over the last `chargeWindow` fraction of the
+ *             cycle (the clouds gathering light before the strike);
+ *   STRIKE  — at the cycle boundary: a rapid flicker (real lightning
+ *             strobes — a bright burst plus two decaying rebounds) and a
+ *             soft afterglow that decays into the next cycle's quiet.
+ * Deterministic (no Math.random), so the same system storms the same way
+ * every run. The strike sits at the cycle boundary (t ≡ phase mod period).
+ *
+ * @param {number} nowMs game clock (ms)
+ * @param {number} intervalSec seconds per storm cycle
+ * @param {number} strikeDurSec the flicker's span (seconds)
+ * @param {number} [phaseSec=0] per-cluster phase offset (seconds)
+ * @param {number} [chargeWindow=0.45] fraction of the cycle over which charge rises
+ * @returns {{charge:number, flash:number}} both 0..1
+ */
+export function stormEnvelope(nowMs, intervalSec, strikeDurSec, phaseSec = 0, chargeWindow = 0.45) {
+  const period = Math.max(2, Number(intervalSec) || 12);
+  const W = Math.max(0.15, Number(strikeDurSec) || 0.5);
+  const cw = Math.min(1, Math.max(0.1, Number(chargeWindow) || 0.45));
+  const t = nowMs / 1000 - (Number(phaseSec) || 0);
+  const tLocal = ((t % period) + period) % period; // 0..period; strike at tLocal === 0 (≡ period)
+
+  // CHARGE: 0 early in the cycle, rising smoothly to 1 at the strike.
+  const u = tLocal / period;
+  const charge = sstep01((u - (1 - cw)) / cw);
+
+  // FLASH: time relative to the strike (negative = before it). The
+  // afterglow is clipped at 3× the flicker span (it is negligible there —
+  // a hard 0 keeps the envelope exact instead of an asymptote).
+  const dt = tLocal <= period / 2 ? tLocal : tLocal - period; // (-period/2, period/2]
+  let flash = 0;
+  if (dt >= 0 && dt <= 3 * W) {
+    const gauss = (x, sigma) => Math.exp(-(x * x) / (2 * sigma * sigma));
+    // A bright primary burst + two decaying rebounds (the strobe) +
+    // a soft afterglow (light that lingers in the cloud).
+    const b1 = 1.0 * gauss(dt, 0.12 * W);
+    const b2 = 0.55 * gauss(dt - 0.45 * W, 0.1 * W);
+    const b3 = 0.35 * gauss(dt - 0.85 * W, 0.09 * W);
+    const afterglow = 0.22 * Math.exp(-dt / (0.9 * W));
+    flash = Math.min(1, b1 + b2 + b3 + afterglow);
+  }
+  return { charge, flash };
+}
+
 // --- Color grade (pure; the shader does the same thing per-pixel) ---------
 
 /**