Initial commit

shared/bodyStyle.js

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+/**
+ * Body style — three appearance sliders inspired by dreamfall simhuman
+ * global morphs (mass / muscle / fat).
+ *
+ * Plain numbers only: Party, C path, and client mesh build all share this.
+ * Ranges match vibe-human MODELING_CONTROLS for body.global.*:
+ *   mass   −1 lean … +1 heavy
+ *   muscle −1 soft … +1 muscular
+ *   fat     0 base … +1 fat  (no negative target in the reference)
+ */
+
+export const BODY_STYLE_DEFAULTS = Object.freeze({
+  mass: 0,
+  muscle: 0,
+  fat: 0,
+});
+
+/** Slider metadata for the kit chest UI. */
+export const BODY_STYLE_SLIDERS = Object.freeze([
+  {
+    id: 'mass',
+    label: 'Mass',
+    min: -1,
+    max: 1,
+    step: 0.01,
+    left: 'Lean',
+    right: 'Heavy',
+  },
+  {
+    id: 'muscle',
+    label: 'Muscle',
+    min: -1,
+    max: 1,
+    step: 0.01,
+    left: 'Soft',
+    right: 'Muscular',
+  },
+  {
+    id: 'fat',
+    label: 'Fat',
+    min: 0,
+    max: 1,
+    step: 0.01,
+    left: 'Base',
+    right: 'Heavy',
+  },
+]);
+
+function clamp(v, lo, hi) {
+  const n = Number(v);
+  if (!Number.isFinite(n)) return lo;
+  return Math.max(lo, Math.min(hi, n));
+}
+
+/**
+ * Normalize a partial body bag. Missing keys become 0 (average build).
+ * @param {unknown} raw
+ * @returns {{ mass: number, muscle: number, fat: number }}
+ */
+export function normalizeBodyStyle(raw) {
+  if (!raw || typeof raw !== 'object') {
+    return { ...BODY_STYLE_DEFAULTS };
+  }
+  return {
+    mass: clamp(raw.mass, -1, 1),
+    muscle: clamp(raw.muscle, -1, 1),
+    fat: clamp(raw.fat, 0, 1),
+  };
+}
+
+/** True when every channel is at the neutral default. */
+export function isDefaultBodyStyle(style) {
+  const s = normalizeBodyStyle(style);
+  return s.mass === 0 && s.muscle === 0 && s.fat === 0;
+}
+
+/**
+ * Compact wire form for full-roster snapshots (two decimals).
+ * @returns {{ m: number, u: number, f: number }}
+ */
+export function packBodyStyle(style) {
+  const s = normalizeBodyStyle(style);
+  return {
+    m: Math.round(s.mass * 100) / 100,
+    u: Math.round(s.muscle * 100) / 100,
+    f: Math.round(s.fat * 100) / 100,
+  };
+}
+
+/** Inverse of packBodyStyle — also accepts full { mass, muscle, fat }. */
+export function unpackBodyStyle(raw) {
+  if (!raw || typeof raw !== 'object') return normalizeBodyStyle(null);
+  if ('mass' in raw || 'muscle' in raw || 'fat' in raw) {
+    return normalizeBodyStyle(raw);
+  }
+  return normalizeBodyStyle({
+    mass: raw.m,
+    muscle: raw.u,
+    fat: raw.f,
+  });
+}
+
+/**
+ * Ease unit strength so mid-slider stays mild and the last third punches
+ * harder into caricature (leaner / bulkier / more cut / fatter).
+ * @param {number} t 0..1
+ * @returns {number} 0..1
+ */
+function easeExtreme(t) {
+  const a = clamp(t, 0, 1);
+  // ~0.35 at half travel, 1.0 at the end — more of the gain sits near the stop.
+  return a * 0.35 + a * a * 0.25 + a * a * a * 0.4;
+}
+
+/** Signed ease: preserves direction, applies easeExtreme on |v|. */
+function shapedSigned(v) {
+  if (v === 0) return 0;
+  return Math.sign(v) * easeExtreme(Math.abs(v));
+}
+
+/**
+ * Map mass/muscle/fat onto the loft physique scalars used by buildBodyGeometry.
+ *
+ * Ends of each slider push hard (ease-in + large peak gains). Mid values stay
+ * readable so average builds do not jump. Seeded rng still adds a small natural
+ * variation so two fighters with the same sliders are not voxel-identical.
+ *
+ * @param {{ mass: number, muscle: number, fat: number }} style
+ * @param {{ range: (a: number, b: number) => number }} rng
+ */
+export function physiqueFromBodyStyle(style, rng) {
+  const s = normalizeBodyStyle(style);
+  // Shaped channels: mild near 0, extreme at ±1 / 1.
+  const mass = shapedSigned(s.mass);
+  const muscle = shapedSigned(s.muscle);
+  const fat = easeExtreme(s.fat);
+
+  // Peak gains (at shaped = ±1 / 1) — roughly 2× the first-pass response so
+  // full lean / tank / soft / cut / fat reads clearly under armor.
+  // Overall girth: mass + fat dominate; muscle adds a little.
+  const bulkBase = 1 + mass * 0.32 + fat * 0.26 + muscle * 0.1;
+  // Waist: fat fills hard, muscle nips, mass thickens.
+  const waistBase = 1 + fat * 0.48 + mass * 0.2 - muscle * 0.18;
+  // Shoulders / chest: muscle primary.
+  const shoulderBase = 1 + muscle * 0.42 + mass * 0.16 + fat * 0.1;
+  // Arms: muscle, with a little mass/fat.
+  const armBase = 1 + muscle * 0.48 + mass * 0.14 + fat * 0.12;
+  // Legs: fat + mass, muscle secondary.
+  const legBase = 1 + fat * 0.36 + mass * 0.2 + muscle * 0.16;
+  // Head: slight only — keeps helm fit.
+  const headBase = 1 + mass * 0.06 + fat * 0.05;
+
+  const jitter = (base, lo = 0.97, hi = 1.03) => base * (rng?.range?.(lo, hi) ?? 1);
+
+  return {
+    bulk: jitter(bulkBase),
+    // Lower floors so full lean/soft can actually go thin.
+    waistF: Math.max(0.52, jitter(waistBase, 0.98, 1.02)),
+    shoulderF: Math.max(0.62, jitter(shoulderBase, 0.98, 1.02)),
+    armF: Math.max(0.58, jitter(armBase, 0.97, 1.03)),
+    legF: Math.max(0.6, jitter(legBase, 0.97, 1.03)),
+    headF: Math.max(0.85, jitter(headBase, 0.98, 1.02)),
+    style: s,
+  };
+}