# Newbury Exhibit v2

Fan-made shared multi-viewer AR experience for a physical LEGO® Hidden Side™ town
display. Multiple phones point at printed ArUco markers ("Newbury Crests") and see
the same server-driven ghosts anchored to real-world positions, each from their own
viewpoint. Tribute project — not affiliated with or endorsed by the LEGO Group.

## Stack
Node 20 (Express + ws) in Docker · Three.js r160 (CDN import map) · js-aruco2
(ARUCO_4X4_1000, vendored) · vanilla ES-module client.

## Units
**All world coordinates are centimetres** (1 Three.js unit = 1 cm): anchor/spawn/building
positions and sizes, wander radius, calibration readouts. Marker print size stays in mm
(`sizeMM`); the mm→cm conversion happens once in `fuse.js`.

## Baked-in AR fixes (hard-won, do not "simplify" these)
- **POS-IT pose**: **raw** centered image coords into POS-IT (no Y pre-flip — pre-flipping
  double-inverts the vertical axis and makes tilt respond backwards); rotation used
  **as-is**; translation **Y and Z negated** (`-t[1]`, `-t[2]`). A/B toggle: `FLIP_INPUT_Y`
  in `public/js/ar/pose.js`.
- **Planar-ambiguity flips**: per-marker temporal consistency — pick the POS-IT solution
  closest to the previous frame (`public/js/ar/pose.js`).
- **Phantom marker IDs**: `maxHammingDistance: 0` (`public/js/ar/detect.js`).
- **Multi-marker flicker**: confidence-weighted quaternion slerp fusion, hemisphere-aligned,
  weighted by marker screen area (`public/js/ar/fuse.js`). Place anchors densely so ≥2
  crests are visible from any viewing angle.
- **Vendor load order matters**: `cv → svd → posit1 → aruco → dictionary`.

## Features
- **Playlist engine** (server-driven, all viewers in sync): N concurrent ghosts,
  per-ghost dwell time then rotate through the whole roster, shuffle/roster order,
  color/rarity filters, optional time-of-day windows, crossfade in/out.
- **Paths**: waypoint routes (loop or pingpong) drawn in the 3D editor — ghosts walk them
  at constant speed and turn to face each new direction, like they live there. Waypoints are
  full 3D so paths can climb. Path motion is deterministic (pure function of time), same as wander.
- **Rarity system**: `weighted` order makes Commons appear often and Legendaries rarely
  (per-rarity appearance weights), and `movementScale` shrinks how much rarer ghosts move.
- **Residents**: pin any ghost permanently to a spawn or path (`residents` in the playlist);
  they never rotate out and their spot is excluded from rotation.
- **Behaviors**: static float (bob + idle sway) or wander (deterministic orbit-drift —
  a pure function of server spawn record + wall clock, so every phone computes the
  same motion with zero position streaming). Wander is 3D: horizontal radius plus a
  configurable vertical amplitude (`wanderVertical`, cm).
- **Anchors ("Newbury Crests")**: flat (horizontal) / wall (vertical) / custom mounts,
  fully editable — position, yaw/pitch/roll trim, printed size, enable toggle.
- **3D layout editor** (`/admin/layout.html`): Three.js orbit view with drag gizmos
  (5 mm snap, green arrow = height) for anchors, occlusion buildings, and spawn points —
  spawn Y is fully editable so ghosts can live at any height. Anchors render through the
  exact same `anchorWorldMatrix` the AR pipeline uses, each with a white orientation arrow;
  compass rose on the grid (N = +Z = back of table). Top-view button, property panel,
  save/reset-to-seed.
- **Placement plan printer** (`/admin/plan.html`): to-scale top-down plan of the whole
  layout — at 1:1 the actual crest patterns print true-size in position, so you can tape
  the sheets to the table and the markers are already placed. Tiles across A4/A3 with
  10 mm overlap, crop marks, join labels (A1/B2…), overview page with tile map, per-layer
  toggles, grid ruler and compass. 1:2 / 1:5 / fit scales for checking proportions.
- **Playlist manager** (`/admin/playlist.html`), **crest print sheet** (`/admin/print.html`,
  true-to-size), **calibration** (`/admin/calibrate.html`: live distance/angle/jitter +
  fused pose), **client error log** (`/admin/errors.html`).
- **Occlusion**: buildings render as invisible depth-only volumes so ghosts pass behind them.
- **Multi-part OBJ ghosts**: legs/wisp + torso + head + headpiece assembled and tinted with
  the recovered Hidden Side gradient shader (Red/Angry, Yellow/Crazy, Blue/Sad). Procedural
  wisp fallback until models are dropped into `public/models/` and listed in the model
  manifest (`GET/PUT /api/models`).

## Modes
- `EXHIBIT_MODE=dev` — admin pages open, on-screen client error overlay, errors reported
  to `/api/client-errors`.
- `EXHIBIT_MODE=final` — admin + setup pages require `ADMIN_PASSWORD` (12 h tokens).

## Run
```bash
cp .env.example .env       # set mode + password
docker compose up -d --build
# http://host:33044          → viewer
# http://host:33044/admin/layout.html → admin
```
Live edits (layout, playlist, models) persist in the `exhibit-live` volume and survive
rebuilds; `POST /api/scene/reset` restores the committed seed.

## Deploy on blackpearl
```bash
git clone https://gitea.hideawaygaming.com.au/jessikitty/newbury-exhibit-v2.git
cd newbury-exhibit-v2 && cp .env.example .env && bash deploy.sh
```
Then nginx-proxy 33044 with HTTPS (camera + sensors require a secure context).

## Adding your OBJ ghost models
1. Drop parts into `public/models/<id>/` (e.g. `legs.obj`, `torso.obj`, `head.obj`, `headpiece.obj`).
2. Register via the models API (or edit `data/models.json` seed):
```json
{ "models": [ { "id": "minifig", "scale": 1.0, "parts": {
  "legs": "/models/minifig/legs.obj", "torso": "/models/minifig/torso.obj",
  "head": "/models/minifig/head.obj", "headpiece": "/models/minifig/headpiece.obj" } } ] }
```
The gradient shader recolors every part by the ghost's color type automatically.