animations

shared/player.js

@@ -0,0 +1,121 @@
+/**
+ * Player definition — identity traits that are not sim state.
+ *
+ * Appearance (body style, jersey) and locomotion (velocity, effort) live
+ * elsewhere. This bag is the stable "who is this skater" record: how they hold
+ * a stick, which side they shoot from, and anything else that picks a pose set
+ * rather than a frame of motion.
+ *
+ * Kept plain and three.js-free so the same record can travel over the wire.
+ */
+
+/** Which side of the body the stick lives on, and which way they shoot. */
+export const SHOT_SIDE = Object.freeze({
+  LEFT: 'left',
+  RIGHT: 'right',
+});
+
+/**
+ * Defaults for a new player bag.
+ *
+ * Authored stickwork (GRIP targets, arm poses) is written for a **right**
+ * shot: top hand on the right, lower hand on the left, forehand at −X in
+ * skater space. A **left** shot mirrors that set across the body midline.
+ */
+export const PLAYER_DEFAULTS = Object.freeze({
+  shotSide: SHOT_SIDE.RIGHT,
+});
+
+/**
+ * Accept the spellings we are likely to see and fold them to `'left' | 'right'`.
+ *
+ * @param {unknown} v
+ * @returns {'left' | 'right'}
+ */
+export function normalizeShotSide(v) {
+  if (v === SHOT_SIDE.LEFT || v === 'L' || v === 'l' || v === -1 || v === false) {
+    return SHOT_SIDE.LEFT;
+  }
+  if (v === SHOT_SIDE.RIGHT || v === 'R' || v === 'r' || v === 1 || v === true) {
+    return SHOT_SIDE.RIGHT;
+  }
+  return PLAYER_DEFAULTS.shotSide;
+}
+
+/**
+ * Sign used to mirror authored right-shot content onto a left shot.
+ * `+1` = as authored (right), `-1` = mirror across the sagittal plane (left).
+ *
+ * @param {unknown} side
+ * @returns {1 | -1}
+ */
+export function shotSign(side) {
+  return normalizeShotSide(side) === SHOT_SIDE.LEFT ? -1 : 1;
+}
+
+/**
+ * Top hand on the stick for this shot side.
+ * Right shot: right hand on top. Left shot: left hand on top.
+ *
+ * @param {unknown} side
+ * @returns {'L' | 'R'}
+ */
+export function topHandFor(side) {
+  return normalizeShotSide(side) === SHOT_SIDE.LEFT ? 'L' : 'R';
+}
+
+/**
+ * Lower (blade-side) hand — the one IK pins to the shaft.
+ *
+ * @param {unknown} side
+ * @returns {'L' | 'R'}
+ */
+export function lowerHandFor(side) {
+  return normalizeShotSide(side) === SHOT_SIDE.LEFT ? 'R' : 'L';
+}
+
+/**
+ * Rough real-world split (~62% left shot in the NHL). Used when a roster
+ * entry does not specify a side, so a lineup is not all clones.
+ *
+ * @param {number} u01 uniform in [0, 1)
+ * @returns {'left' | 'right'}
+ */
+export function rollShotSide(u01) {
+  const u = Number.isFinite(u01) ? u01 : 0.5;
+  return u < 0.62 ? SHOT_SIDE.LEFT : SHOT_SIDE.RIGHT;
+}
+
+/**
+ * Normalize a partial player bag. Missing keys take the defaults.
+ *
+ * @param {unknown} raw
+ * @returns {{ shotSide: 'left' | 'right' }}
+ */
+export function normalizePlayer(raw) {
+  if (!raw || typeof raw !== 'object') {
+    return { shotSide: PLAYER_DEFAULTS.shotSide };
+  }
+  return {
+    shotSide: normalizeShotSide(/** @type {{ shotSide?: unknown }} */ (raw).shotSide),
+  };
+}
+
+/**
+ * Compact wire form for roster snapshots.
+ * @returns {{ ss: 'L' | 'R' }}
+ */
+export function packPlayer(player) {
+  const p = normalizePlayer(player);
+  return { ss: p.shotSide === SHOT_SIDE.LEFT ? 'L' : 'R' };
+}
+
+/** Inverse of packPlayer — also accepts a full `{ shotSide }` bag. */
+export function unpackPlayer(raw) {
+  if (!raw || typeof raw !== 'object') return normalizePlayer(null);
+  if ('shotSide' in raw) return normalizePlayer(raw);
+  const ss = /** @type {{ ss?: unknown }} */ (raw).ss;
+  if (ss === 'L' || ss === 'l') return { shotSide: SHOT_SIDE.LEFT };
+  if (ss === 'R' || ss === 'r') return { shotSide: SHOT_SIDE.RIGHT };
+  return normalizePlayer(null);
+}

shared/skaterSim.js

@@ -1,5 +1,6 @@
 import { clamp, lerpAngle, wrapAngle } from './scalar.js';
 import { clampToRink } from './rink.js';
+import { normalizePlayer } from './player.js';
 
 /**
  * Skating locomotion.
@@ -55,6 +56,7 @@ export const SKATE = Object.freeze({
 });
 
 export function createSkaterState(id, spawn = {}, opts = {}) {
+  const player = normalizePlayer(opts.player ?? opts);
   return {
     id,
     name: opts.name ?? `Skater ${id}`,
@@ -62,6 +64,12 @@ export function createSkaterState(id, spawn = {}, opts = {}) {
     seed: opts.seed ?? 1337,
     team: opts.team ?? 0,
 
+    /**
+     * Stable identity traits — shot side, and anything else that picks a pose
+     * set rather than a frame of motion. See `shared/player.js`.
+     */
+    shotSide: player.shotSide,
+
     x: spawn.x ?? 0,
     y: 0,
     z: spawn.z ?? 0,