refactor: update file paths in poker documentation

Remove the `parts/` and `setup/` prefixes from file references in
`games/poker/poker.md` to match the updated file structure.

.gitattributes

@@ -0,0 +1,7 @@
+# Game assets are large binaries; store them in Git LFS.
+games/**/*.png filter=lfs diff=lfs merge=lfs -text
+games/**/*.jpg filter=lfs diff=lfs merge=lfs -text
+games/**/*.jpeg filter=lfs diff=lfs merge=lfs -text
+games/**/*.webp filter=lfs diff=lfs merge=lfs -text
+games/**/*.glb filter=lfs diff=lfs merge=lfs -text
+games/**/*.gltf filter=lfs diff=lfs merge=lfs -text

apps/proxy/src/config.ts

@@ -0,0 +1,12 @@
+/**
+ * Runtime config for the proxy. `GAMES_ROOT` is set at startup (from env or a
+ * default) and read by the asset/trace routes to serve local game assets. It's
+ * a module-level value because the node-server adapter injects its own
+ * `HttpBindings` as the Hono env, not custom bindings.
+ */
+export let GAMES_ROOT: string | undefined;
+
+/** Set the games root at startup. */
+export function setGamesRoot(root: string | undefined): void {
+  GAMES_ROOT = root;
+}

apps/proxy/src/env.test.ts

@@ -3,9 +3,10 @@ import { loadEnv } from './env.js';
 
 describe('loadEnv', () => {
   it('parses a valid environment', () => {
-    expect(loadEnv({ STEAM_API_KEY: 'key', PORT: '4000' })).toEqual({
+    expect(loadEnv({ STEAM_API_KEY: 'key', PORT: '4000', GAMES_ROOT: '/games' })).toEqual({
       STEAM_API_KEY: 'key',
       PORT: 4000,
+      GAMES_ROOT: '/games',
     });
   });
 

apps/proxy/src/env.ts

@@ -3,6 +3,8 @@ import { z } from 'zod';
 const envSchema = z.object({
   STEAM_API_KEY: z.string().min(1).optional(),
   PORT: z.coerce.number().int().min(1).max(65535).default(3000),
+  /** Absolute path to the games root, for serving local game assets. */
+  GAMES_ROOT: z.string().min(1).optional(),
 });
 
 export type Env = z.infer<typeof envSchema>;
@@ -11,6 +13,7 @@ export type Env = z.infer<typeof envSchema>;
 export interface Bindings {
   STEAM_API_KEY?: string;
   PORT: number;
+  GAMES_ROOT?: string;
 }
 
 export function loadEnv(source: NodeJS.ProcessEnv = process.env): Env {

apps/proxy/src/index.ts

@@ -1,7 +1,10 @@
 import { serve } from '@hono/node-server';
 import { cors } from 'hono/cors';
 import { Hono } from 'hono';
+import { fileURLToPath } from 'node:url';
+import * as path from 'node:path';
 import { loadEnv, type Bindings } from './env.js';
+import { setGamesRoot } from './config.js';
 import asset from './routes/asset.js';
 import health from './routes/health.js';
 import items from './routes/items.js';
@@ -10,6 +13,13 @@ import trace from './routes/trace.js';
 
 const env = loadEnv();
 
+// Default GAMES_ROOT to the repo's `games` folder so local game assets work
+// without configuration; override via env.
+setGamesRoot(
+  env.GAMES_ROOT ??
+    path.resolve(path.dirname(fileURLToPath(import.meta.url)), '..', '..', '..', 'games'),
+);
+
 const app = new Hono<{ Bindings: Bindings }>();
 
 app.use('*', cors());

apps/proxy/src/routes/asset.test.ts

@@ -1,8 +1,20 @@
-import { afterEach, describe, expect, it, vi } from 'vitest';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import * as path from 'node:path';
+import { mkdtempSync, writeFileSync } from 'node:fs';
+import { tmpdir } from 'node:os';
 import asset from './asset.js';
+import { setGamesRoot } from '../config.js';
+
+let dir: string;
+
+beforeEach(() => {
+  dir = mkdtempSync(path.join(tmpdir(), 'games-'));
+  setGamesRoot(dir);
+});
 
 afterEach(() => {
   vi.unstubAllGlobals();
+  setGamesRoot(undefined);
 });
 
 describe('asset route', () => {
@@ -40,4 +52,22 @@ describe('asset route', () => {
     const res = await asset.request('/?url=https%3A%2F%2Fexample.com%2Fa.png');
     expect(res.status).toBe(502);
   });
+
+  it('serves a local game asset from GAMES_ROOT', async () => {
+    writeFileSync(path.join(dir, 'cards.png'), new Uint8Array([1, 2, 3]));
+    const res = await asset.request('/?url=cards.png');
+    expect(res.status).toBe(200);
+    expect(res.headers.get('content-type')).toBe('image/png');
+    expect(await res.arrayBuffer()).toEqual(new Uint8Array([1, 2, 3]).buffer);
+  });
+
+  it('returns 404 for a missing local asset', async () => {
+    const res = await asset.request('/?url=nope.png');
+    expect(res.status).toBe(404);
+  });
+
+  it('rejects path traversal outside GAMES_ROOT', async () => {
+    const res = await asset.request('/?url=..%2F..%2Fetc%2Fpasswd');
+    expect(res.status).toBe(400);
+  });
 });

apps/proxy/src/routes/asset.ts

@@ -1,4 +1,6 @@
 import { Hono } from 'hono';
+import { GAMES_ROOT } from '../config.js';
+import { resolveAsset } from './resolveAsset.js';
 
 const app = new Hono();
 
@@ -7,6 +9,10 @@ const app = new Hono();
  * client. Workshop asset hosts (steamusercontent.com, etc.) often omit CORS
  * headers, which would block `TextureLoader` / `GLTFLoader` in the browser.
  * Routing through the proxy makes those assets loadable.
+ *
+ * A relative URL (no scheme) is treated as a game asset path relative to the
+ * `GAMES_ROOT` directory and served from disk, so bgm parts can reference
+ * local files (e.g. `poker/parts/assets/cards.png`).
  */
 app.get('/', async (c) => {
   const raw = c.req.query('url');
@@ -14,20 +20,28 @@ app.get('/', async (c) => {
     return c.json({ error: 'Missing url query param' }, 400);
   }
 
-  let url: URL;
+  const result = await resolveAsset(raw, GAMES_ROOT);
-  try {
+  if (!result.ok) {
-    url = new URL(raw);
+    // A missing local file vs an invalid reference.
-  } catch {
+    return c.json(
-    return c.json({ error: 'Invalid url query param' }, 400);
+      { error: result.reason === 'not-found' ? 'Asset not found' : 'Invalid url query param' },
+      result.reason === 'not-found' ? 404 : 400,
+    );
   }
-  // Only allow http(s) to avoid SSRF via file://, etc.
+  const asset = result.asset;
-  if (url.protocol !== 'http:' && url.protocol !== 'https:') {
+
-    return c.json({ error: 'Only http(s) urls are allowed' }, 400);
+  if (asset.stream) {
+    return new Response(asset.stream as unknown as BodyInit, {
+      headers: {
+        'Content-Type': asset.contentType,
+        'Cache-Control': 'public, max-age=86400',
+      },
+    });
   }
 
   let res: Response;
   try {
-    res = await fetch(url);
+    res = await fetch(asset.url!);
   } catch (err) {
     return c.json({ error: `Failed to fetch asset: ${String(err)}` }, 502);
   }

apps/proxy/src/routes/resolveAsset.ts

@@ -0,0 +1,76 @@
+import { createReadStream } from 'node:fs';
+import { stat } from 'node:fs/promises';
+import * as path from 'node:path';
+
+/** Content-type by extension for local game assets. */
+const CONTENT_TYPES: Record<string, string> = {
+  '.png': 'image/png',
+  '.jpg': 'image/jpeg',
+  '.jpeg': 'image/jpeg',
+  '.gif': 'image/gif',
+  '.webp': 'image/webp',
+  '.svg': 'image/svg+xml',
+  '.gltf': 'model/gltf+json',
+  '.glb': 'model/gltf-binary',
+  '.obj': 'text/plain',
+  '.fbx': 'application/octet-stream',
+};
+
+export interface ResolvedAsset {
+  /** The http(s) URL to fetch, when the asset is remote. */
+  url?: string;
+  /** A readable stream of a local file, when the asset is on disk. */
+  stream?: NodeJS.ReadableStream;
+  contentType: string;
+}
+
+export type ResolveResult =
+  | { ok: true; asset: ResolvedAsset }
+  | { ok: false; reason: 'invalid' | 'not-found' };
+
+/**
+ * Resolve an asset reference to either a remote http(s) URL or a local file
+ * under `gamesRoot`. A reference with a scheme is remote; otherwise it's a
+ * game asset path relative to `gamesRoot`. Returns `{ ok: false }` with a
+ * reason when the reference is invalid (non-http scheme, path traversal) or
+ * the file is missing.
+ */
+export async function resolveAsset(
+  raw: string,
+  gamesRoot: string | undefined,
+): Promise<ResolveResult> {
+  // A relative path (no scheme) is a local game asset.
+  if (!/^[a-z][a-z0-9+.-]*:/i.test(raw)) {
+    if (!gamesRoot) return { ok: false, reason: 'invalid' };
+    const rel = raw.replace(/^\/+/, '');
+    const abs = path.resolve(gamesRoot, rel);
+    if (!abs.startsWith(path.resolve(gamesRoot) + path.sep)) {
+      return { ok: false, reason: 'invalid' };
+    }
+    try {
+      await stat(abs);
+    } catch {
+      return { ok: false, reason: 'not-found' };
+    }
+    const ext = path.extname(abs).toLowerCase();
+    return {
+      ok: true,
+      asset: {
+        stream: createReadStream(abs),
+        contentType: CONTENT_TYPES[ext] ?? 'application/octet-stream',
+      },
+    };
+  }
+
+  let url: URL;
+  try {
+    url = new URL(raw);
+  } catch {
+    return { ok: false, reason: 'invalid' };
+  }
+  // Only allow http(s) to avoid SSRF via file://, etc.
+  if (url.protocol !== 'http:' && url.protocol !== 'https:') {
+    return { ok: false, reason: 'invalid' };
+  }
+  return { ok: true, asset: { url: raw, contentType: 'application/octet-stream' } };
+}

apps/proxy/src/routes/trace.ts

@@ -4,6 +4,8 @@ import sharp from 'sharp';
 import { createRequire } from 'module';
 import { traceRequestSchema, type TraceResult } from '@tts/shared';
 import { offsetShape, parseSvgShape } from './svgShape.js';
+import { resolveAsset } from './resolveAsset.js';
+import { GAMES_ROOT } from '../config.js';
 
 // vtracer is a CommonJS package; load it via require so the wasm initializes
 // with the correct `__dirname`.
@@ -39,19 +41,29 @@ app.get('/', async (c) => {
   const { url, mode, threshold, format, simplify, maxColors, offset } =
     parsed.data;
 
-  // Only allow http(s) to avoid SSRF via file://, etc.
+  // Resolve the image: a relative path is a local game asset under GAMES_ROOT;
-  const parsedUrl = new URL(url);
+  // otherwise it must be an http(s) URL.
-  if (parsedUrl.protocol !== 'http:' && parsedUrl.protocol !== 'https:') {
+  const resolved = await resolveAsset(url, GAMES_ROOT);
-    return c.json({ error: 'Only http(s) urls are allowed' }, 400);
+  if (!resolved.ok) {
+    return c.json({ error: 'Invalid or missing image url' }, 400);
   }
+  const asset = resolved.asset;
 
   let image: Buffer;
   try {
-    const res = await fetch(url);
+    if (asset.stream) {
+      const chunks: Buffer[] = [];
+      for await (const chunk of asset.stream) {
+        chunks.push(Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk));
+      }
+      image = Buffer.concat(chunks);
+    } else {
+      const res = await fetch(asset.url!);
       if (!res.ok) {
         return c.json({ error: `Image responded ${res.status}` }, 502);
       }
       image = Buffer.from(await res.arrayBuffer());
+    }
   } catch (err) {
     return c.json({ error: `Failed to fetch image: ${String(err)}` }, 502);
   }

apps/web/package.json

@@ -22,6 +22,8 @@
     "@tts/mesh": "workspace:*",
     "@tts/shared": "workspace:*",
     "@tts/bgm": "workspace:*",
+    "@tts/http": "workspace:*",
+    "@tts/tabletop": "workspace:*",
     "bson": "^7.3.1",
     "react": "^19.2.8",
     "react-dom": "^19.2.8",

apps/web/src/api.ts

@@ -1,5 +1,7 @@
-import { deserialize } from 'bson';
+import type { SearchResult, TTSMod } from '@tts/shared';
-import type { SearchResult, TraceResult, TTSMod } from '@tts/shared';
+import { traceImage } from '@tts/http';
+
+export { traceImage };
 
 const BASE = '';
 
@@ -19,27 +21,8 @@ export function searchWorkshop(q: string, page = 1): Promise<SearchResult> {
 }
 
 /**
- * Trace an image into a vector shape, BSON-deserializing the proxy response.
+ * Fetch a full parsed TTS save.
- * `mode` controls how the region is derived (`alpha`, `bw`, `color`); a
- * non-zero `offset` insets (negative) or outsets (positive) the shape in
- * pixels.
  */
-export async function traceImage(
-  url: string,
-  mode: 'alpha' | 'bw' | 'color' = 'alpha',
-  offset?: number,
-): Promise<TraceResult> {
-  const params = new URLSearchParams({ url, mode });
-  if (offset !== undefined) params.set('offset', String(offset));
-  const res = await fetch(`${BASE}/trace?${params.toString()}`);
-  if (!res.ok) {
-    const body = (await res.json().catch(() => null)) as { error?: string } | null;
-    throw new Error(body?.error ?? `Trace failed (${res.status})`);
-  }
-  return deserialize(new Uint8Array(await res.arrayBuffer())) as TraceResult;
-}
-
-/** Fetch a full parsed TTS save. */
 export function fetchMod(id: string, fileUrl?: string): Promise<TTSMod> {
   const params = new URLSearchParams();
   if (fileUrl) params.set('fileUrl', fileUrl);

apps/web/src/components/viewers/CardViewer.tsx

@@ -8,7 +8,7 @@ import {
   type ExtrudedGeometry,
 } from '@tts/mesh';
 import Scene from './Scene';
-import { assetUrl } from './assetUrl';
+import { assetUrl } from '@tts/http';
 import { cardAspect, resolveCardConfig, spriteUv } from './cardResolution';
 import { flipTexture } from './flipTexture';
 import { getSharedGeometry, objectTint, tintedColor } from './sharedResources';

apps/web/src/components/viewers/CustomModelViewer.tsx

@@ -5,7 +5,7 @@ import type { TTSObject } from '@tts/shared';
 import * as THREE from 'three';
 import type { Object3D } from 'three';
 import Scene from './Scene';
-import { assetUrl } from './assetUrl';
+import { assetUrl } from '@tts/http';
 import { FlexibleModelLoader } from './flexibleModelLoader';
 import { objectTint, tintedColor } from './sharedResources';
 

apps/web/src/components/viewers/TileViewer.tsx

@@ -12,7 +12,7 @@ import {
   type ExtrudedGeometry,
 } from '@tts/mesh';
 import Scene from './Scene';
-import { assetUrl } from './assetUrl';
+import { assetUrl } from '@tts/http';
 import { flipTexture } from './flipTexture';
 import {
   getSharedGeometry,

apps/web/src/components/viewers/TokenViewer.tsx

@@ -3,14 +3,15 @@ import { useMemo } from 'react';
 import * as THREE from 'three';
 import type { TTSObject } from '@tts/shared';
 import {
+  circleShape,
   extrudeShapeParts,
+  traceToShape,
+  traceToUvBounds,
   type ExtrudedGeometry,
-  type Shape,
-  type UVBounds,
 } from '@tts/mesh';
-import { traceImage } from '../../api';
+import { traceImage } from '@tts/http';
 import Scene from './Scene';
-import { assetUrl } from './assetUrl';
+import { assetUrl } from '@tts/http';
 import {
   getSharedGeometry,
   getSharedMaterial,
@@ -71,8 +72,9 @@ export function TokenMesh({
   const { front, back, walls } = useMemo(() => {
     // The traced shape and its UV framing share the same transform, so the
     // full image rectangle maps to the same bounds in mesh coordinates.
-    const shape = trace ? toMeshShape(trace) : circleShape();
+    const scale = TOKEN_SIZE / Math.max(trace?.width ?? 0, trace?.height ?? 0);
-    const uvBounds = trace ? toUvBounds(trace) : undefined;
+    const shape = trace ? traceToShape(trace, scale) : circleShape(TOKEN_SIZE / 2);
+    const uvBounds = trace ? traceToUvBounds(trace, scale) : undefined;
     const parts = extrudeShapeParts(shape, { height: thickness, uvBounds });
     // Shared across tokens with the same source image (the trace is cached per
     // URL, so the silhouette is deterministic) so the full-setup view reuses
@@ -154,71 +156,3 @@ function toGeometry(extruded: ExtrudedGeometry) {
   geo.setIndex(new THREE.BufferAttribute(indices, 1));
   return geo;
 }
-
-/** A circle fallback when there's no image to trace. */
-function circleShape(): Shape {
-  const pts: number[][] = [];
-  for (let i = 0; i < 48; i++) {
-    const a = (i / 48) * Math.PI * 2;
-    pts.push([Math.cos(a) * (TOKEN_SIZE / 2), Math.sin(a) * (TOKEN_SIZE / 2)]);
-  }
-  return { outline: pts };
-}
-
-/**
- * Convert a traced shape (image pixel coords, origin top-left, y-down) to a
- * mesh `Shape` (y-up, centered at the origin). Flips the y-axis, scales to
- * `TOKEN_SIZE`, centers the result, and normalizes winding so the outline is
- * counter-clockwise and holes are clockwise (as `@tts/mesh` expects).
- */
-function toMeshShape(trace: {
-  shape: { outline: number[][]; holes?: number[][][] };
-  width: number;
-  height: number;
-}): Shape {
-  const { shape, width, height } = trace;
-  const scale = TOKEN_SIZE / Math.max(width, height);
-  const ox = (width * scale) / 2;
-  const oy = (height * scale) / 2;
-  const transform = (pts: number[][]) =>
-    pts.map(([x, y]) => [x! * scale - ox, (height - y!) * scale - oy]);
-  return {
-    outline: normalizeWinding(transform(shape.outline), true),
-    holes: shape.holes?.map((h) => normalizeWinding(transform(h), false)),
-  };
-}
-
-/**
- * The full image rectangle, in mesh coordinates, used as the UV framing so the
- * texture aligns with the traced silhouette (which may be smaller than the
- * image when there is transparent padding).
- */
-function toUvBounds(trace: {
-  width: number;
-  height: number;
-}): UVBounds {
-  const scale = TOKEN_SIZE / Math.max(trace.width, trace.height);
-  const ox = (trace.width * scale) / 2;
-  const oy = (trace.height * scale) / 2;
-  return { minX: -ox, minY: -oy, maxX: ox, maxY: oy };
-}
-
-/**
- * Ensure a ring has the requested winding. `ccw` true yields a
- * counter-clockwise ring (outline); false yields clockwise (hole).
- */
-function normalizeWinding(pts: number[][], ccw: boolean): number[][] {
-  const isCcw = signedArea(pts) > 0;
-  return isCcw === ccw ? pts : [...pts].reverse();
-}
-
-/** Signed area of a polygon; positive means counter-clockwise. */
-function signedArea(points: number[][]): number {
-  let area = 0;
-  for (let i = 0; i < points.length; i++) {
-    const [x1, y1] = points[i]!;
-    const [x2, y2] = points[(i + 1) % points.length]!;
-    area += x1! * y2! - x2! * y1!;
-  }
-  return area / 2;
-}

apps/web/src/components/viewers/assetUrl.ts

@@ -1,8 +0,0 @@
-/**
- * Route an external asset URL through the proxy so it can be loaded by
- * three.js loaders (TextureLoader, GLTFLoader, etc.) despite the upstream host
- * omitting CORS headers.
- */
-export function assetUrl(url: string): string {
-  return `/asset?url=${encodeURIComponent(url)}`;
-}

apps/web/src/pages/ModPage.tsx

@@ -6,7 +6,7 @@ import { useModStore } from '../stores/modStore';
 import { useSearchStore } from '../stores/searchStore';
 import { modFileUrl } from '../api';
 import ObjectTree from '../components/ObjectTree';
-import ErrorBoundary from '../components/ErrorBoundary';
+import { ErrorBoundary } from '@tts/tabletop';
 import { resolveViewer } from '../components/viewers';
 import { iconsForObject } from '../components/objectIcons';
 // Register the 3D viewers (side effect) so `resolveViewer` can find them.

apps/web/src/pages/PartPage.tsx

@@ -1,6 +1,8 @@
 import { useParams } from 'react-router-dom';
+import { PartView, ErrorBoundary } from '@tts/tabletop';
 import Breadcrumbs from '../components/Breadcrumbs';
 import PackageMissing from '../components/PackageMissing';
+import Scene from '../components/viewers/Scene';
 import { findPackage } from './bgm';
 
 /** Detail view for a single part within a package. */
@@ -35,6 +37,14 @@ export default function PartPage() {
               {found.fillet ? ` · fillet ${found.fillet}mm` : ''}
             </p>
           </div>
+          {/* The boundary wraps the Canvas (Scene), not PartView, so its HTML
+              fallback renders outside the r3f namespace. The library's proxy
+              calls default to the host's `/asset` and `/trace` paths. */}
+          <ErrorBoundary>
+            <Scene>
+              <PartView part={found} baseUrl={found.baseUrl} />
+            </Scene>
+          </ErrorBoundary>
           <pre className="overflow-x-auto rounded-lg border border-zinc-800 bg-zinc-900 p-3 text-xs text-zinc-400">
             {JSON.stringify(found, null, 2)}
           </pre>

docs/bgm-loader-status.md

@@ -14,7 +14,7 @@
 | `src/markdown.ts` | Virtual def files from markdown code blocks, via **`marked`**. `file=` naming + content-hash auto-naming (`./<hash>.yaml`); multiple blocks may share a `file=` name |
 | `src/parse.ts` | yaml/json/toml → def objects (`yaml`, `smol-toml`); real-file walker (incl. `.csv`) |
 | `src/variants.ts` | `$variants` expansion via **`typed-csv`** (`typed-csv/csv-loader`). Inline (newline) vs path; paths resolve against the virtual def map |
-| `src/collect.ts` | `loadDefs` (real + virtual, virtual wins), `collectPackages` (package decl → `include` globs via **picomatch** → parts/surfaces/setups, `type#id` uniqueness, `$variants` on defs and route candidates) |
+| `src/collect.ts` | `loadDefs` (real + virtual, virtual wins), `collectPackages` (package decl → `include` globs via **picomatch** → parts/surfaces/setups, `type#id` uniqueness, `$variants` on defs and route candidates). Sets each part's `baseUrl` to its source file's directory for resolving relative asset paths |
 | `src/vite.ts` | The **vite plugin** (`bgm()`): resolves `virtual:bgm/packages` (all packages) and `virtual:bgm/package/<id>` (one package) imports to `export default <json>`, watches source files for reload. Serializes the package's `Map`s to objects (`SerializedPackage`); throws on unknown packages; re-collects per `load` (no stale cache). |
 | `src/*.test.ts` | **23 tests, all passing** — markdown extractor, typed-csv parsing (incl. the spec's empty-array + crop tuple cases), full harbor collection, plugin unit tests (resolve/load/shape/watch), and a real `vite build` integration test covering two packages |
 
@@ -24,6 +24,22 @@ Deps: `marked`, `typed-csv`, `yaml`, `smol-toml`, `picomatch`, `zod`, `vite`, `@
 
 Exercises the format end-to-end: package decl, two `file=parts/tokens.yaml` blocks, a table surface with `mount`/`children` and `candidates: $variants` against a virtual csv block, a child player surface, and a setup declaring its enabled `surfaces`. Same content duplicated as the vitest fixture under `packages/bgm/src/__fixtures__/harbor/`.
 
+### `games/poker/poker.md` — example game (new)
+
+A real 52-card deck: a single `card` part expanded by `$variants` into 52 cards, each picking a cell from a `13×4` face sheet (`cards-13x4.jpg`) and a shared `4×1` back sheet (`back-4x1.png`). Assets are stored in Git LFS (`.gitattributes`).
+
+### `packages/tabletop` — rendering library (new)
+
+A standalone r3f library that renders bgm parts. `PartView`/`PartMesh` build a mesh from a `Part` definition via `@tts/mesh` (size/fillet, face/back sprite UVs, traced `shape` or rect fallback). Proxy calls (`/asset`, `/trace`) default to `@tts/http` handlers and are overridable via `TabletopProvider`. Plan: [`bgm-tabletop-plan.md`](./bgm-tabletop-plan.md).
+
+### `packages/http` — shared proxy HTTP (new)
+
+CORS-safe proxy HTTP helpers shared by the web app and `@tts/tabletop`: `assetUrl`/`resolveAssetUrl` (route external assets through `/asset`) and `traceImage` (image → vector shape via `/trace`, BSON-deserialized). The trace-to-shape geometry conversion lives in `@tts/mesh` (`traceToShape`/`traceToUvBounds`), and `ErrorBoundary` is shared via `@tts/tabletop`.
+
+### `apps/proxy` — local game assets (new)
+
+The proxy serves local game assets from the `games` root: `GAMES_ROOT` (env or default) is set at startup (`config.ts`) and read by the `/asset` and `/trace` routes to serve relative paths (e.g. `poker/parts/assets/cards.png`) from disk, alongside the existing http(s) proxy path.
+
 ### `apps/web` — consumer (new)
 
 - `vite.config.ts` — wired with `bgm({ root: <repo>/games })`, importing the plugin from `@tts/bgm`.
@@ -36,9 +52,10 @@ The vite plugin itself lives in `packages/bgm/src/vite.ts` (exported from `@tts/
 ## Works
 
 - `pnpm --filter @tts/bgm build` and `typecheck` pass.
-- Root `pnpm test`: **177 pass**.
+- Root `pnpm test`: **191 pass**.
 - `pnpm --filter @tts/web build` succeeds; config warnings fixed.
 - `src/vite.test.ts` runs a **real `vite build`** against a self-contained fixture (`src/__fixtures__/vite-build/`) and asserts the bundled output contains the package data — the plugin is proven end-to-end without touching the web app.
+- `pnpm --filter @tts/tabletop build` / `test` pass; `pnpm --filter @tts/proxy typecheck` passes.
 
 ## Known issues
 

games/poker/poker.md

@@ -16,74 +16,75 @@ language: en
 ## Parts
 
 A single `card` part expanded into 52 cards by the `$variants` CSV. Each row
-picks a cell from a `13×5` sprite sheet — 13 ranks across, 4 suits down, and
+picks a cell from the `13×4` face sheet (`cards-13x4.jpg`) — 13 ranks across,
-a shared card-back row at index 4.
+4 suits down. All cards share the same back from the `4×1` back sheet
+(`back-4x1.png`).
 
-```yaml file=parts/cards.yaml
+```yaml file=cards.yaml
 role: part
 type: card
-face: ./assets/cards.png
+face: ./cards-13x4.jpg
-back: ./assets/cards.png
+back: ./back-4x1.png
 size: [63, 88, 3]
 fillet: 2
 $variants: ./cards.csv
 ```
 
-```csv file=parts/cards.csv
+```csv file=cards.csv
 id,rank,suit,faceCrop,backCrop
 string,string,string,[number;number;number;number],[number;number;number;number]
-2s,2,spades,[0;0;13;5],[0;4;13;5]
+2s,2,spades,[0;0;13;4],[0;0;4;1]
-3s,3,spades,[1;0;13;5],[0;4;13;5]
+3s,3,spades,[1;0;13;4],[0;0;4;1]
-4s,4,spades,[2;0;13;5],[0;4;13;5]
+4s,4,spades,[2;0;13;4],[0;0;4;1]
-5s,5,spades,[3;0;13;5],[0;4;13;5]
+5s,5,spades,[3;0;13;4],[0;0;4;1]
-6s,6,spades,[4;0;13;5],[0;4;13;5]
+6s,6,spades,[4;0;13;4],[0;0;4;1]
-7s,7,spades,[5;0;13;5],[0;4;13;5]
+7s,7,spades,[5;0;13;4],[0;0;4;1]
-8s,8,spades,[6;0;13;5],[0;4;13;5]
+8s,8,spades,[6;0;13;4],[0;0;4;1]
-9s,9,spades,[7;0;13;5],[0;4;13;5]
+9s,9,spades,[7;0;13;4],[0;0;4;1]
-10s,10,spades,[8;0;13;5],[0;4;13;5]
+10s,10,spades,[8;0;13;4],[0;0;4;1]
-js,J,spades,[9;0;13;5],[0;4;13;5]
+js,J,spades,[9;0;13;4],[0;0;4;1]
-qs,Q,spades,[10;0;13;5],[0;4;13;5]
+qs,Q,spades,[10;0;13;4],[0;0;4;1]
-ks,K,spades,[11;0;13;5],[0;4;13;5]
+ks,K,spades,[11;0;13;4],[0;0;4;1]
-as,A,spades,[12;0;13;5],[0;4;13;5]
+as,A,spades,[12;0;13;4],[0;0;4;1]
-2h,2,hearts,[0;1;13;5],[0;4;13;5]
+2h,2,hearts,[0;1;13;4],[0;0;4;1]
-3h,3,hearts,[1;1;13;5],[0;4;13;5]
+3h,3,hearts,[1;1;13;4],[0;0;4;1]
-4h,4,hearts,[2;1;13;5],[0;4;13;5]
+4h,4,hearts,[2;1;13;4],[0;0;4;1]
-5h,5,hearts,[3;1;13;5],[0;4;13;5]
+5h,5,hearts,[3;1;13;4],[0;0;4;1]
-6h,6,hearts,[4;1;13;5],[0;4;13;5]
+6h,6,hearts,[4;1;13;4],[0;0;4;1]
-7h,7,hearts,[5;1;13;5],[0;4;13;5]
+7h,7,hearts,[5;1;13;4],[0;0;4;1]
-8h,8,hearts,[6;1;13;5],[0;4;13;5]
+8h,8,hearts,[6;1;13;4],[0;0;4;1]
-9h,9,hearts,[7;1;13;5],[0;4;13;5]
+9h,9,hearts,[7;1;13;4],[0;0;4;1]
-10h,10,hearts,[8;1;13;5],[0;4;13;5]
+10h,10,hearts,[8;1;13;4],[0;0;4;1]
-jh,J,hearts,[9;1;13;5],[0;4;13;5]
+jh,J,hearts,[9;1;13;4],[0;0;4;1]
-qh,Q,hearts,[10;1;13;5],[0;4;13;5]
+qh,Q,hearts,[10;1;13;4],[0;0;4;1]
-kh,K,hearts,[11;1;13;5],[0;4;13;5]
+kh,K,hearts,[11;1;13;4],[0;0;4;1]
-ah,A,hearts,[12;1;13;5],[0;4;13;5]
+ah,A,hearts,[12;1;13;4],[0;0;4;1]
-2d,2,diamonds,[0;2;13;5],[0;4;13;5]
+2d,2,diamonds,[0;2;13;4],[0;0;4;1]
-3d,3,diamonds,[1;2;13;5],[0;4;13;5]
+3d,3,diamonds,[1;2;13;4],[0;0;4;1]
-4d,4,diamonds,[2;2;13;5],[0;4;13;5]
+4d,4,diamonds,[2;2;13;4],[0;0;4;1]
-5d,5,diamonds,[3;2;13;5],[0;4;13;5]
+5d,5,diamonds,[3;2;13;4],[0;0;4;1]
-6d,6,diamonds,[4;2;13;5],[0;4;13;5]
+6d,6,diamonds,[4;2;13;4],[0;0;4;1]
-7d,7,diamonds,[5;2;13;5],[0;4;13;5]
+7d,7,diamonds,[5;2;13;4],[0;0;4;1]
-8d,8,diamonds,[6;2;13;5],[0;4;13;5]
+8d,8,diamonds,[6;2;13;4],[0;0;4;1]
-9d,9,diamonds,[7;2;13;5],[0;4;13;5]
+9d,9,diamonds,[7;2;13;4],[0;0;4;1]
-10d,10,diamonds,[8;2;13;5],[0;4;13;5]
+10d,10,diamonds,[8;2;13;4],[0;0;4;1]
-jd,J,diamonds,[9;2;13;5],[0;4;13;5]
+jd,J,diamonds,[9;2;13;4],[0;0;4;1]
-qd,Q,diamonds,[10;2;13;5],[0;4;13;5]
+qd,Q,diamonds,[10;2;13;4],[0;0;4;1]
-kd,K,diamonds,[11;2;13;5],[0;4;13;5]
+kd,K,diamonds,[11;2;13;4],[0;0;4;1]
-ad,A,diamonds,[12;2;13;5],[0;4;13;5]
+ad,A,diamonds,[12;2;13;4],[0;0;4;1]
-2c,2,clubs,[0;3;13;5],[0;4;13;5]
+2c,2,clubs,[0;3;13;4],[0;0;4;1]
-3c,3,clubs,[1;3;13;5],[0;4;13;5]
+3c,3,clubs,[1;3;13;4],[0;0;4;1]
-4c,4,clubs,[2;3;13;5],[0;4;13;5]
+4c,4,clubs,[2;3;13;4],[0;0;4;1]
-5c,5,clubs,[3;3;13;5],[0;4;13;5]
+5c,5,clubs,[3;3;13;4],[0;0;4;1]
-6c,6,clubs,[4;3;13;5],[0;4;13;5]
+6c,6,clubs,[4;3;13;4],[0;0;4;1]
-7c,7,clubs,[5;3;13;5],[0;4;13;5]
+7c,7,clubs,[5;3;13;4],[0;0;4;1]
-8c,8,clubs,[6;3;13;5],[0;4;13;5]
+8c,8,clubs,[6;3;13;4],[0;0;4;1]
-9c,9,clubs,[7;3;13;5],[0;4;13;5]
+9c,9,clubs,[7;3;13;4],[0;0;4;1]
-10c,10,clubs,[8;3;13;5],[0;4;13;5]
+10c,10,clubs,[8;3;13;4],[0;0;4;1]
-jc,J,clubs,[9;3;13;5],[0;4;13;5]
+jc,J,clubs,[9;3;13;4],[0;0;4;1]
-qc,Q,clubs,[10;3;13;5],[0;4;13;5]
+qc,Q,clubs,[10;3;13;4],[0;0;4;1]
-kc,K,clubs,[11;3;13;5],[0;4;13;5]
+kc,K,clubs,[11;3;13;4],[0;0;4;1]
-ac,A,clubs,[12;3;13;5],[0;4;13;5]
+ac,A,clubs,[12;3;13;4],[0;0;4;1]
 ```
 
 ## Board
@@ -91,7 +92,7 @@ ac,A,clubs,[12;3;13;5],[0;4;13;5]
 A table with a draw pile on the left and five community-card slots across the
 middle. The deck pile fans its stacked cards along a curve.
 
-```yaml file=parts/board.yaml
+```yaml file=board.yaml
 type: board
 id: poker
 role: surface
@@ -110,7 +111,7 @@ layout:
       $variants: ./community.csv
 ```
 
-```csv file=parts/community.csv
+```csv file=community.csv
 slot,x,y,rotation
 string,number,number,number
 0,-100,0,0
@@ -125,7 +126,7 @@ string,number,number,number
 Deal the whole deck onto the draw pile (`poker:card` expands to every card of
 that type), then flip a flop onto the community slots.
 
-```yaml file=setup/main.yaml
+```yaml file=main.yaml
 role: setup
 type: game
 id: main

packages/bgm/src/__fixtures__/vite-build/src/vite-env.d.ts

@@ -0,0 +1,18 @@
+/// <reference types="vite/client" />
+
+/**
+ * Ambient types for the virtual `bgm` modules served by the bgm vite plugin,
+ * so the fixture's entry typechecks in the editor (the plugin provides them at
+ * build time). Mirrors `apps/web/src/vite-env.d.ts`.
+ */
+declare module 'virtual:bgm/packages' {
+  import type { SerializedPackage } from '@tts/bgm';
+  const packages: SerializedPackage[];
+  export default packages;
+}
+
+declare module 'virtual:bgm/package/*' {
+  import type { SerializedPackage } from '@tts/bgm';
+  const pkg: SerializedPackage;
+  export default pkg;
+}

packages/bgm/src/collect.test.ts

@@ -25,6 +25,9 @@ describe('collectPackages', () => {
     });
     expect(wood.face).toBe('./assets/tokens.png');
     expect(wood.faceCrop).toEqual([1, 0, 5, 2]);
+    // Relative assets resolve against the source file's directory. The fixture
+    // markdown sits at the games root, so the virtual file is `parts/tokens.yaml`.
+    expect(wood.baseUrl).toBe('parts/');
 
     // Two surfaces: the table board and its child player board.
     expect([...harbor.surfaces.keys()].sort()).toEqual(['board#harbor', 'board#player']);

packages/bgm/src/collect.ts

@@ -13,6 +13,7 @@
  *
  * See docs/bgm-format.md for the format's concrete behavior.
  */
+import * as path from 'node:path';
 import picomatch from 'picomatch';
 import { collectVirtualFiles } from './markdown.js';
 import { parseDefText, readDefFiles } from './parse.js';
@@ -218,7 +219,13 @@ function asPackage(def: ParsedDef, source: string): PackageDef {
 
 function asPart(obj: Record<string, unknown>, source: string): Part {
   try {
-    return validatePart(obj) as unknown as Part;
+    const part = validatePart(obj) as unknown as Part;
+    // Resolve relative asset paths against the directory of the source file
+    // (path-style name relative to the games root, e.g. `harbor/parts/`).
+    // Real files may carry a leading slash from an empty root; strip it.
+    const dir = path.posix.dirname(source).replace(/^\/+/, '');
+    part.baseUrl = dir ? `${dir}/` : '';
+    return part;
   } catch (err) {
     throw wrapZod(err, source);
   }

packages/bgm/src/types.ts

@@ -69,6 +69,11 @@ export interface Part {
   size?: Size;
   /** Fillet radius in mm; defaults to `0`. */
   fillet?: number;
+  /**
+   * Directory of the part's source file (json/yaml/markdown), for resolving
+   * relative asset paths. Set by the loader; not authored.
+   */
+  baseUrl?: string;
   /** Extra fields from the source definition, kept for forwards compatibility. */
   [key: string]: unknown;
 }

packages/bgm/src/vite.unit.test.ts

@@ -80,7 +80,9 @@ describe('bgm vite plugin', () => {
     const plugin = bgm({ root: gamesRoot });
     const watched: string[] = [];
     const context = { addWatchFile: (file: string) => watched.push(file) };
-    (plugin.buildStart as Callable<typeof plugin.buildStart>).call(context);
+    // Vite 8 (rolldown) `buildStart` takes `(this, options)`; the plugin ignores
+    // the options, so pass a placeholder.
+    (plugin.buildStart as Callable<typeof plugin.buildStart>).call(context, {} as never);
 
     // Every def file (real + virtual code blocks) is watched so edits
     // trigger a re-collect.

packages/http/package.json

@@ -0,0 +1,28 @@
+{
+  "name": "@tts/http",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "main": "./dist/index.js",
+  "types": "./dist/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.js"
+    }
+  },
+  "scripts": {
+    "build": "tsc -p tsconfig.json",
+    "typecheck": "tsc -p tsconfig.json --noEmit",
+    "test": "vitest run",
+    "lint": "echo \"no lint configured\""
+  },
+  "dependencies": {
+    "@tts/shared": "workspace:*",
+    "bson": "^7.3.1"
+  },
+  "devDependencies": {
+    "typescript": "^5.7.2",
+    "vitest": "^4.1.10"
+  }
+}

packages/http/src/asset.test.ts

@@ -0,0 +1,23 @@
+import { describe, expect, it } from 'vitest';
+import { resolveAssetUrl } from './asset.js';
+
+describe('resolveAssetUrl', () => {
+  it('passes absolute urls through unchanged', () => {
+    expect(resolveAssetUrl('https://example.com/a.png', 'harbor/parts/')).toBe(
+      'https://example.com/a.png',
+    );
+    expect(resolveAssetUrl('data:image/png;base64,AAAA', 'harbor/parts/')).toBe(
+      'data:image/png;base64,AAAA',
+    );
+  });
+
+  it('resolves a relative path against baseUrl', () => {
+    expect(resolveAssetUrl('./assets/tokens.png', 'harbor/parts/')).toBe(
+      'harbor/parts/assets/tokens.png',
+    );
+  });
+
+  it('returns the relative path as-is without a baseUrl', () => {
+    expect(resolveAssetUrl('./assets/tokens.png')).toBe('./assets/tokens.png');
+  });
+});

packages/http/src/asset.ts

@@ -0,0 +1,26 @@
+/**
+ * Asset URL helpers for the host app's CORS-safe asset proxy (`/asset`).
+ * Shared by the web viewers and `@tts/tabletop`, which both route external
+ * assets (textures, models) through the proxy so three.js can load them.
+ */
+
+/**
+ * Resolve a part's asset URL. Absolute URLs (http/https, data:, blob:) pass
+ * through unchanged; relative paths are resolved against `baseUrl` — the
+ * directory of the part's source file (the json/yaml/markdown that defined
+ * it). Without a `baseUrl`, a relative path is returned as-is.
+ */
+export function resolveAssetUrl(url: string, baseUrl?: string): string {
+  if (/^(https?:|data:|blob:)/i.test(url)) return url;
+  if (!baseUrl) return url;
+  // `baseUrl` is a path relative to the games root (no scheme), so join rather
+  // than resolve as a URL. A fake origin lets `new URL` normalize `./` and
+  // `../`; the origin is stripped from the result.
+  const resolved = new URL(url, `http://localhost/${baseUrl}`).pathname;
+  return resolved.replace(/^\/+/, '');
+}
+
+/** Route an external asset URL through the proxy so three.js can load it. */
+export function assetUrl(url: string): string {
+  return `/asset?url=${encodeURIComponent(url)}`;
+}

packages/http/src/index.ts

@@ -0,0 +1,3 @@
+export { resolveAssetUrl, assetUrl } from './asset.js';
+export { traceImage } from './trace.js';
+export type { TraceResult } from '@tts/shared';

packages/http/src/trace.ts

@@ -0,0 +1,27 @@
+/**
+ * Trace an image into a vector shape via the host app's proxy (`/trace`).
+ * Shared by the web token viewer and `@tts/tabletop`, which both trace an
+ * image's alpha channel into a silhouette for extrusion.
+ */
+import { deserialize } from 'bson';
+import type { TraceResult } from '@tts/shared';
+
+/**
+ * Trace an image into a vector shape, BSON-deserializing the proxy response.
+ * `mode` controls how the region is derived (`alpha`, `bw`, `color`); a
+ * non-zero `offset` insets (negative) or outsets (positive) the shape.
+ */
+export async function traceImage(
+  url: string,
+  mode: 'alpha' | 'bw' | 'color' = 'alpha',
+  offset?: number,
+): Promise<TraceResult> {
+  const params = new URLSearchParams({ url, mode });
+  if (offset !== undefined) params.set('offset', String(offset));
+  const res = await fetch(`/trace?${params.toString()}`);
+  if (!res.ok) {
+    const body = (await res.json().catch(() => null)) as { error?: string } | null;
+    throw new Error(body?.error ?? `Trace failed (${res.status})`);
+  }
+  return deserialize(new Uint8Array(await res.arrayBuffer())) as TraceResult;
+}

packages/http/tsconfig.json

@@ -0,0 +1,9 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": {
+    "outDir": "./dist",
+    "rootDir": "./src",
+    "lib": ["ES2022", "DOM"]
+  },
+  "include": ["src"]
+}

packages/http/vitest.config.ts

@@ -0,0 +1,7 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  test: {
+    include: ['src/**/*.test.ts'],
+  },
+});

packages/mesh/src/index.ts

@@ -3,3 +3,4 @@ export * from './shapes.js';
 export * from './tessellate.js';
 export * from './walls.js';
 export * from './extrude.js';
+export * from './trace.js';

packages/mesh/src/trace.test.ts

@@ -0,0 +1,45 @@
+import { describe, expect, it } from 'vitest';
+import { traceToShape, traceToUvBounds } from './trace.js';
+
+describe('traceToShape', () => {
+  it('flips y and centers the traced shape', () => {
+    const trace = {
+      shape: { outline: [[0, 0], [10, 0], [10, 10], [0, 10]] },
+      width: 10,
+      height: 10,
+    };
+    const shape = traceToShape(trace, 0.2);
+    // Centered at origin, scaled to fit the 2x2 box. The y-flip reverses
+    // winding, so the outline is normalized to CCW (order may differ).
+    expect(shape.outline).toHaveLength(4);
+    expect(shape.outline).toEqual(
+      expect.arrayContaining([
+        [-1, 1],
+        [1, 1],
+        [1, -1],
+        [-1, -1],
+      ]),
+    );
+  });
+
+  it('maps holes to clockwise winding', () => {
+    const trace = {
+      shape: {
+        outline: [[0, 0], [10, 0], [10, 10], [0, 10]],
+        holes: [[[2, 2], [2, 8], [8, 8], [8, 2]]],
+      },
+      width: 10,
+      height: 10,
+    };
+    const shape = traceToShape(trace, 0.2);
+    expect(shape.holes).toHaveLength(1);
+    expect(shape.holes![0]).toHaveLength(4);
+  });
+});
+
+describe('traceToUvBounds', () => {
+  it('maps the full image rectangle to the part box', () => {
+    const bounds = traceToUvBounds({ width: 10, height: 20 }, 0.2);
+    expect(bounds).toEqual({ minX: -1, minY: -2, maxX: 1, maxY: 2 });
+  });
+});

packages/mesh/src/trace.ts

@@ -0,0 +1,67 @@
+/**
+ * Trace-to-shape helpers: convert a proxy `/trace` result (image pixel coords,
+ * origin top-left, y-down) into a mesh `Shape` (y-up, centered at the origin).
+ *
+ * Shared by the web token viewer and `@tts/tabletop`, which both trace an
+ * image's alpha channel into a silhouette and extrude it. The only difference
+ * between consumers is the scale factor, so the transform is parameterized by
+ * `scale` and the callers compute it (fit-to-box vs fit-to-max-dimension).
+ */
+import type { Shape } from './shapes.js';
+import type { UVBounds } from './types.js';
+
+/** A traced image region, in image pixel coords (origin top-left, y-down). */
+export interface TraceInput {
+  shape: { outline: number[][]; holes?: number[][][] };
+  width: number;
+  height: number;
+}
+
+/**
+ * Convert a traced shape to a mesh `Shape` scaled by `scale`. Flips the y-axis
+ * (image y-down → mesh y-up), centers the result at the origin, and normalizes
+ * winding so the outline is counter-clockwise and holes are clockwise (as
+ * `@tts/mesh` expects).
+ */
+export function traceToShape(trace: TraceInput, scale: number): Shape {
+  const { shape, width, height } = trace;
+  const ox = (width * scale) / 2;
+  const oy = (height * scale) / 2;
+  const transform = (pts: number[][]) =>
+    pts.map(([x, y]) => [x! * scale - ox, (height - y!) * scale - oy]);
+  return {
+    outline: normalizeWinding(transform(shape.outline), true),
+    holes: shape.holes?.map((h) => normalizeWinding(transform(h), false)),
+  };
+}
+
+/**
+ * The full image rectangle, in mesh coordinates, used as the UV framing so the
+ * texture aligns with a traced silhouette (which may be smaller than the image
+ * when there is transparent padding).
+ */
+export function traceToUvBounds(
+  trace: { width: number; height: number },
+  scale: number,
+): UVBounds {
+  const ox = (trace.width * scale) / 2;
+  const oy = (trace.height * scale) / 2;
+  return { minX: -ox, minY: -oy, maxX: ox, maxY: oy };
+}
+
+/** Ensure a ring has the requested winding. `ccw` true yields CCW (outline). */
+function normalizeWinding(pts: number[][], ccw: boolean): number[][] {
+  const isCcw = signedArea(pts) > 0;
+  return isCcw === ccw ? pts : [...pts].reverse();
+}
+
+/** Signed area of a polygon; positive means counter-clockwise. */
+function signedArea(points: number[][]): number {
+  let area = 0;
+  for (let i = 0; i < points.length; i++) {
+    const [x1, y1] = points[i]!;
+    const [x2, y2] = points[(i + 1) % points.length]!;
+    area += x1! * y2! - x2! * y1!;
+  }
+  return area / 2;
+}

packages/tabletop/package.json

@@ -0,0 +1,37 @@
+{
+  "name": "@tts/tabletop",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "main": "./dist/index.js",
+  "types": "./dist/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.js"
+    }
+  },
+  "scripts": {
+    "build": "tsc -p tsconfig.json",
+    "typecheck": "tsc -p tsconfig.json --noEmit",
+    "test": "vitest run",
+    "lint": "echo \"no lint configured\""
+  },
+  "dependencies": {
+    "@react-three/drei": "^10.7.8",
+    "@react-three/fiber": "^9.7.0",
+    "@react-three/postprocessing": "^3.0.4",
+    "@tts/bgm": "workspace:*",
+    "@tts/http": "workspace:*",
+    "@tts/mesh": "workspace:*",
+    "react": "^19.2.8",
+    "three": "^0.185.1",
+    "zustand": "^5.0.14"
+  },
+  "devDependencies": {
+    "@types/react": "^19.2.18",
+    "@types/three": "^0.185.4",
+    "typescript": "^5.7.2",
+    "vitest": "^4.1.10"
+  }
+}

packages/tabletop/src/ErrorBoundary.tsx

@@ -12,8 +12,8 @@ interface State {
 
 /**
  * Catches render errors in its subtree and renders a fallback instead of
- * letting them crash the whole page. Used to isolate failures in object
+ * letting them crash the whole page. Used to isolate failures in part viewers
- * viewers (e.g. WebGL context loss, model/texture load errors).
+ * (e.g. WebGL context loss, texture/trace load errors).
  */
 export default class ErrorBoundary extends Component<Props, State> {
   override state: State = { error: null };
@@ -24,7 +24,7 @@ export default class ErrorBoundary extends Component<Props, State> {
 
   override componentDidCatch(error: Error, info: ErrorInfo) {
     // Surface the error for debugging without breaking the UI.
-    console.error('Viewer error:', error, info.componentStack);
+    console.error('Part viewer error:', error, info.componentStack);
   }
 
   override render() {
@@ -40,7 +40,7 @@ export default class ErrorBoundary extends Component<Props, State> {
 function DefaultFallback({ error }: { error: Error }) {
   return (
     <div className="flex h-80 flex-col items-center justify-center gap-2 overflow-auto rounded-lg border border-zinc-800 bg-zinc-900 p-4 text-center">
-      <p className="text-sm font-medium text-zinc-200">Couldn't render this object</p>
+      <p className="text-sm font-medium text-zinc-200">Couldn't render this part</p>
       <p className="max-w-sm wrap-break-word font-mono text-xs text-zinc-400">
         {error.message}
       </p>

packages/tabletop/src/http.ts

@@ -0,0 +1,7 @@
+/**
+ * HTTP helpers for loading part assets. Re-exported from `@tts/http`, the
+ * shared package for the host app's proxy (`/asset` and `/trace`) handlers.
+ * Kept as a thin re-export so the tabletop's public surface is unchanged.
+ */
+export { resolveAssetUrl, assetUrl, traceImage } from '@tts/http';
+export type { TraceResult } from '@tts/http';

packages/tabletop/src/index.ts

@@ -0,0 +1,12 @@
+export { PartView, PartMesh } from './partView.js';
+export { default as ErrorBoundary } from './ErrorBoundary.js';
+export { TabletopProvider, useTabletopHttp } from './provider.js';
+export type { TabletopHttp, AssetUrlFn, TraceImageFn } from './provider.js';
+export {
+  partDimensions,
+  spriteUvFromCrop,
+  fallbackShape,
+  traceToShape,
+  traceToUvBounds,
+} from './part.js';
+export { resolveAssetUrl, assetUrl, traceImage } from './http.js';

packages/tabletop/src/part.test.ts

@@ -0,0 +1,81 @@
+import { describe, expect, it } from 'vitest';
+import type { Part } from '@tts/bgm';
+import {
+  partDimensions,
+  spriteUvFromCrop,
+  fallbackShape,
+  traceToShape,
+  traceToUvBounds,
+} from './part.js';
+
+describe('partDimensions', () => {
+  it('converts mm size to world units', () => {
+    const part: Part = { type: 'card', id: 'as', size: [63, 88, 3] };
+    expect(partDimensions(part)).toEqual({ width: 63 / 30, height: 88 / 30, depth: 3 / 30 });
+  });
+
+  it('defaults when no size', () => {
+    const part: Part = { type: 'token', id: 'wood' };
+    expect(partDimensions(part)).toEqual({ width: 2, height: 2, depth: 0.1 });
+  });
+});
+
+describe('spriteUvFromCrop', () => {
+  it('returns full-image UVs without a crop', () => {
+    expect(spriteUvFromCrop(undefined)).toEqual({ repeatX: 1, repeatY: 1, offsetX: 0, offsetY: 0 });
+  });
+
+  it('selects a sprite cell from a crop', () => {
+    // [col, row, cols, rows] — cell at col 1, row 2 of a 13x5 sheet.
+    expect(spriteUvFromCrop([1, 2, 13, 5])).toEqual({
+      repeatX: 1 / 13,
+      repeatY: 1 / 5,
+      offsetX: 1 / 13,
+      offsetY: 1 - 3 / 5,
+    });
+  });
+});
+
+describe('fallbackShape', () => {
+  it('returns a rect without a fillet', () => {
+    const part: Part = { type: 'tile', id: 'x', size: [40, 20, 3] };
+    const shape = fallbackShape(part, 40 / 30, 20 / 30);
+    expect(shape.outline).toHaveLength(4);
+  });
+
+  it('returns a rounded rect with a fillet', () => {
+    const part: Part = { type: 'card', id: 'as', size: [63, 88, 3], fillet: 2 };
+    const shape = fallbackShape(part, 63 / 30, 88 / 30);
+    // 4 corners x 4 segments.
+    expect(shape.outline.length).toBeGreaterThan(4);
+  });
+});
+
+describe('traceToShape', () => {
+  it('flips y and centers the traced shape', () => {
+    const trace = {
+      shape: { outline: [[0, 0], [10, 0], [10, 10], [0, 10]] },
+      width: 10,
+      height: 10,
+    };
+    const shape = traceToShape(trace, 2, 2);
+    // Centered at origin, scaled to fit the 2x2 box. The y-flip reverses
+    // winding, so the outline is normalized to CCW (order may differ).
+    expect(shape.outline).toHaveLength(4);
+    expect(shape.outline).toEqual(
+      expect.arrayContaining([
+        [-1, 1],
+        [1, 1],
+        [1, -1],
+        [-1, -1],
+      ]),
+    );
+  });
+});
+
+describe('traceToUvBounds', () => {
+  it('maps the full image rectangle to the part box', () => {
+    const bounds = traceToUvBounds({ width: 10, height: 20 }, 2, 4);
+    expect(bounds).toEqual({ minX: -1, minY: -2, maxX: 1, maxY: 2 });
+  });
+});

packages/tabletop/src/part.ts

@@ -0,0 +1,91 @@
+/**
+ * Pure helpers for rendering a bgm `Part` as a mesh. Kept free of react-three
+ * so they can be unit-tested in a plain node environment (mirroring the web
+ * app's `cardResolution.ts`).
+ */
+import type { Part, Crop } from '@tts/bgm';
+import {
+  rectShape,
+  roundedRectShape,
+  traceToShape as meshTraceToShape,
+  traceToUvBounds as meshTraceToUvBounds,
+  type Shape,
+} from '@tts/mesh';
+
+/** Scale from mm (the format's `size` unit) to world units. */
+export const MM_TO_WORLD = 1 / 30;
+
+/** Default part size `[w, h, d]` in mm when a part has no `size`. */
+const DEFAULT_SIZE: [number, number, number] = [60, 60, 3];
+
+/** A part's dimensions in world units, derived from its `size` (mm). */
+export function partDimensions(part: Part): { width: number; height: number; depth: number } {
+  const [w, h, d] = part.size ?? DEFAULT_SIZE;
+  return {
+    width: w * MM_TO_WORLD,
+    height: h * MM_TO_WORLD,
+    depth: d * MM_TO_WORLD,
+  };
+}
+
+/**
+ * UV repeat/offset that selects a single sprite from a sheet, given a crop
+ * `[col, row, cols, rows]` that divides the image into a `cols` x `rows` grid
+ * and picks the cell at `[col, row]`. Row 0 is the top of the image (v=1), so
+ * the offset counts down from 1. Without a crop, the whole image is shown.
+ */
+export function spriteUvFromCrop(
+  crop: Crop | undefined,
+): { repeatX: number; repeatY: number; offsetX: number; offsetY: number } {
+  if (!crop) return { repeatX: 1, repeatY: 1, offsetX: 0, offsetY: 0 };
+  const [col, row, cols, rows] = crop;
+  return {
+    repeatX: 1 / cols,
+    repeatY: 1 / rows,
+    offsetX: col / cols,
+    offsetY: 1 - (row + 1) / rows,
+  };
+}
+
+/**
+ * The fallback footprint for a part without a `shape` sprite: a rounded rect
+ * when `fillet` is set, otherwise a plain rect, sized to the part's world
+ * dimensions. The fillet (mm) is converted to world units and clamped to half
+ * the smaller dimension.
+ */
+export function fallbackShape(part: Part, width: number, height: number): Shape {
+  const fillet = (part.fillet ?? 0) * MM_TO_WORLD;
+  if (fillet > 0) {
+    return roundedRectShape(width, height, Math.min(fillet, Math.min(width, height) / 2));
+  }
+  return rectShape(width, height);
+}
+
+/**
+ * Convert a traced shape (image pixel coords, origin top-left, y-down) to a
+ * mesh `Shape` (y-up, centered at the origin), scaled to fit the part's world
+ * `width` x `height` box. Flips the y-axis, centers the result, and normalizes
+ * winding so the outline is counter-clockwise and holes are clockwise (as
+ * `@tts/mesh` expects).
+ */
+export function traceToShape(
+  trace: { shape: { outline: number[][]; holes?: number[][][] }; width: number; height: number },
+  width: number,
+  height: number,
+): Shape {
+  const { width: tw, height: th } = trace;
+  return meshTraceToShape(trace, Math.min(width / tw, height / th));
+}
+
+/**
+ * The full image rectangle, in mesh coordinates, used as the UV framing so the
+ * texture aligns with a traced silhouette (which may be smaller than the image
+ * when there is transparent padding).
+ */
+export function traceToUvBounds(
+  trace: { width: number; height: number },
+  width: number,
+  height: number,
+): { minX: number; minY: number; maxX: number; maxY: number } {
+  return meshTraceToUvBounds(trace, Math.min(width / trace.width, height / trace.height));
+}

packages/tabletop/src/partView.tsx

@@ -0,0 +1,160 @@
+/**
+ * `PartView` — render a bgm `Part` definition as a 3D mesh.
+ *
+ * Builds the mesh from the part's definition using `@tts/mesh` geometry:
+ * - `size` → world dimensions; `fillet` → corner radius.
+ * - `face`/`faceCrop`/`back`/`backCrop` → textures with sprite UVs.
+ * - `shape` → traced silhouette (via the proxy `/trace`); otherwise a
+ *   rect/rounded-rect fallback.
+ *
+ * A standalone component library: it reuses `@tts/mesh` geometry, not the web
+ * app's viewers. The trace endpoint and asset proxy are the only coupling to
+ * the host app's HTTP surface.
+ */
+import { useTexture } from '@react-three/drei';
+import { useMemo } from 'react';
+import * as THREE from 'three';
+import type { Part } from '@tts/bgm';
+import { extrudeShapeParts, type ExtrudedGeometry, type UVBounds } from '@tts/mesh';
+import {
+  fallbackShape,
+  partDimensions,
+  spriteUvFromCrop,
+  traceToShape,
+  traceToUvBounds,
+} from './part.js';
+import { resolveAssetUrl } from './http.js';
+import { useTabletopHttp, type TraceImageFn } from './provider.js';
+
+interface TraceData {
+  shape: { outline: number[][]; holes?: number[][][] };
+  width: number;
+  height: number;
+}
+
+// Cache traces by URL so Suspense doesn't re-issue the request on every render.
+// A URL maps to either a pending promise (while loading) or the resolved value.
+const traceCache = new Map<string, TraceData | null | Promise<TraceData | null>>();
+
+/**
+ * Suspend on the alpha trace for `url`, resolving to the traced shape (or null
+ * when there's no URL / the trace fails). Throws the cached promise only while
+ * it's pending; once resolved, the value is returned directly.
+ */
+export function useTrace(url: string | undefined, traceImage: TraceImageFn): TraceData | null {
+  if (!url) return null;
+  const cached = traceCache.get(url);
+  if (cached === undefined) {
+    const promise = traceImage(url, 'alpha', -2).then((result) => {
+      const value: TraceData | null = result.shape
+        ? { shape: result.shape, width: result.width, height: result.height }
+        : null;
+      traceCache.set(url, value);
+      return value;
+    });
+    traceCache.set(url, promise);
+    throw promise;
+  }
+  if (cached instanceof Promise) throw cached;
+  return cached;
+}
+
+/** A 1x1 transparent placeholder so `useTexture` always receives a URL. */
+const FALLBACK_URL =
+  'data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7';
+
+/**
+ * Render a single part as a mesh. `PartView` is a canvas-internal mesh
+ * component — wrap it (or its containing `<Canvas>`) in `ErrorBoundary` to
+ * isolate render failures, since an HTML fallback can't render inside a canvas.
+ * `baseUrl` resolves relative asset paths against the part's source file
+ * directory (see `resolveAssetUrl`).
+ */
+export function PartView({ part, baseUrl }: { part: Part; baseUrl?: string }) {
+  return <PartMesh part={part} baseUrl={baseUrl} />;
+}
+
+/** The part mesh, exported for composition into a shared scene. */
+export function PartMesh({ part, baseUrl }: { part: Part; baseUrl?: string }) {
+  const { assetUrl, traceImage } = useTabletopHttp();
+  const { width, height, depth } = partDimensions(part);
+  const faceUrl = part.face ? resolveAssetUrl(part.face, baseUrl) : undefined;
+  const backUrl = part.back ? resolveAssetUrl(part.back, baseUrl) : undefined;
+  const shapeUrl = part.shape ? resolveAssetUrl(part.shape, baseUrl) : undefined;
+
+  // Always call both hooks so the hook count is stable across renders.
+  const face = useTexture(faceUrl ? assetUrl(faceUrl) : FALLBACK_URL);
+  const back = useTexture(backUrl ? assetUrl(backUrl) : FALLBACK_URL);
+
+  const trace = useTrace(shapeUrl, traceImage);
+
+  const { frontGeo, backGeo, wallsGeo } = useMemo(() => {
+    const shape = trace ? traceToShape(trace, width, height) : fallbackShape(part, width, height);
+    const uvBounds: UVBounds | undefined = trace ? traceToUvBounds(trace, width, height) : undefined;
+    const parts = extrudeShapeParts(shape, { height: depth, uvBounds });
+    const key = `part:${part.type}#${part.id}:${width}:${height}:${depth}`;
+    return {
+      frontGeo: toGeometry(parts.front, key + ':front'),
+      backGeo: toGeometry(parts.back, key + ':back'),
+      wallsGeo: toGeometry(parts.walls, key + ':walls'),
+    };
+  }, [part, trace, width, height, depth]);
+
+  // Face texture: the sprite cell from the sheet (or the full image when there
+  // is no crop). Cloned so the sprite offset/repeat don't leak into other parts
+  // that share the same sheet URL.
+  const faceMap = useMemo(() => {
+    if (!faceUrl) return null;
+    const tex = face.clone();
+    const { repeatX, repeatY, offsetX, offsetY } = spriteUvFromCrop(part.faceCrop);
+    tex.repeat.set(repeatX, repeatY);
+    tex.offset.set(offsetX, offsetY);
+    return tex;
+  }, [faceUrl, face, part.faceCrop]);
+
+  // Back texture: the sprite cell (or full image), flipped so it reads
+  // correctly instead of being mirrored on the back face.
+  const backMap = useMemo(() => {
+    if (!backUrl) return null;
+    const tex = back.clone();
+    const { repeatX, repeatY, offsetX, offsetY } = spriteUvFromCrop(part.backCrop);
+    tex.repeat.set(repeatX, repeatY);
+    tex.offset.set(offsetX, offsetY);
+    tex.repeat.x = -tex.repeat.x;
+    tex.offset.x -= tex.repeat.x;
+    return tex;
+  }, [backUrl, back, part.backCrop]);
+
+  const wallColor = new THREE.Color('#ffffff');
+
+  return (
+    <group>
+      <mesh geometry={frontGeo}>
+        <meshStandardMaterial color={faceMap ? '#ffffff' : '#52525b'} map={faceMap ?? undefined} roughness={0.6} />
+      </mesh>
+      <mesh geometry={backGeo}>
+        <meshStandardMaterial color={backMap ? '#ffffff' : '#52525b'} map={backMap ?? undefined} roughness={0.6} />
+      </mesh>
+      <mesh geometry={wallsGeo}>
+        <meshStandardMaterial color={wallColor} roughness={0.6} />
+      </mesh>
+    </group>
+  );
+}
+
+// Shared geometry cache so repeated parts reuse buffers.
+const geometryCache = new Map<string, THREE.BufferGeometry>();
+
+/** Convert raw extruded arrays into a cached three.js `BufferGeometry`. */
+function toGeometry(extruded: ExtrudedGeometry, key: string): THREE.BufferGeometry {
+  const cached = geometryCache.get(key);
+  if (cached) return cached;
+  const { positions, normals, uvs, indices } = extruded;
+  const geo = new THREE.BufferGeometry();
+  geo.setAttribute('position', new THREE.BufferAttribute(positions, 3));
+  geo.setAttribute('normal', new THREE.BufferAttribute(normals, 3));
+  geo.setAttribute('uv', new THREE.BufferAttribute(uvs, 2));
+  geo.setIndex(new THREE.BufferAttribute(indices, 1));
+  geometryCache.set(key, geo);
+  return geo;
+}

packages/tabletop/src/provider.tsx

@@ -0,0 +1,47 @@
+import { createContext, useContext, type ReactNode } from 'react';
+import { assetUrl as defaultAssetUrl, traceImage as defaultTraceImage, type TraceResult } from './http.js';
+
+/** Build a proxy URL for an external asset (texture, model, etc.). */
+export type AssetUrlFn = (url: string) => string;
+
+/** Trace an image into a vector shape via the proxy. */
+export type TraceImageFn = (
+  url: string,
+  mode?: 'alpha' | 'bw' | 'color',
+  offset?: number,
+) => Promise<TraceResult>;
+
+export interface TabletopHttp {
+  /** Route an asset URL through the host's proxy. */
+  assetUrl: AssetUrlFn;
+  /** Trace an image into a shape via the host's proxy. */
+  traceImage: TraceImageFn;
+}
+
+const defaultHttp: TabletopHttp = {
+  assetUrl: defaultAssetUrl,
+  traceImage: defaultTraceImage,
+};
+
+const TabletopHttpContext = createContext<TabletopHttp>(defaultHttp);
+
+/**
+ * Provide the HTTP handlers the tabletop library uses to reach the host's
+ * proxy (`/asset` and `/trace`). The library defaults to its own handlers that
+ * hit the conventional proxy paths; a host app can override them (e.g. to point
+ * at a different base URL or inject auth).
+ */
+export function TabletopProvider({
+  http = defaultHttp,
+  children,
+}: {
+  http?: TabletopHttp;
+  children: ReactNode;
+}) {
+  return <TabletopHttpContext.Provider value={http}>{children}</TabletopHttpContext.Provider>;
+}
+
+/** The active HTTP handlers for the current subtree. */
+export function useTabletopHttp(): TabletopHttp {
+  return useContext(TabletopHttpContext);
+}

packages/tabletop/tsconfig.json

@@ -0,0 +1,11 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": {
+    "outDir": "./dist",
+    "rootDir": "./src",
+    "lib": ["ES2022", "DOM"],
+    "jsx": "react-jsx"
+  },
+  "include": ["src"],
+  "exclude": ["src/**/*.test.ts"]
+}

packages/tabletop/vitest.config.ts

@@ -0,0 +1,7 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  test: {
+    include: ['src/**/*.test.ts'],
+  },
+});

pnpm-lock.yaml

@@ -87,12 +87,18 @@ importers:
       '@tts/extract':
         specifier: workspace:*
         version: link:../../packages/extract
+      '@tts/http':
+        specifier: workspace:*
+        version: link:../../packages/http
       '@tts/mesh':
         specifier: workspace:*
         version: link:../../packages/mesh
       '@tts/shared':
         specifier: workspace:*
         version: link:../../packages/shared
+      '@tts/tabletop':
+        specifier: workspace:*
+        version: link:../../packages/tabletop
       bson:
         specifier: ^7.3.1
         version: 7.3.1
@@ -187,6 +193,22 @@ importers:
         specifier: ^5.7.2
         version: 5.9.3
 
+  packages/http:
+    dependencies:
+      '@tts/shared':
+        specifier: workspace:*
+        version: link:../shared
+      bson:
+        specifier: ^7.3.1
+        version: 7.3.1
+    devDependencies:
+      typescript:
+        specifier: ^5.7.2
+        version: 5.9.3
+      vitest:
+        specifier: ^4.1.10
+        version: 4.1.10(@types/node@22.20.1)(vite@8.2.1(@types/node@22.20.1)(esbuild@0.28.1)(jiti@2.7.0)(tsx@4.23.11)(yaml@2.9.0))
+
   packages/mesh:
     dependencies:
       earcut:
@@ -216,6 +238,49 @@ importers:
         specifier: ^5.7.2
         version: 5.9.3
 
+  packages/tabletop:
+    dependencies:
+      '@react-three/drei':
+        specifier: ^10.7.8
+        version: 10.7.8(@react-three/fiber@9.7.0(@types/react@19.2.18)(react-dom@19.2.8(react@19.2.8))(react@19.2.8)(three@0.185.1))(@types/react@19.2.18)(@types/three@0.185.4)(react-dom@19.2.8(react@19.2.8))(react@19.2.8)(three@0.185.1)
+      '@react-three/fiber':
+        specifier: ^9.7.0
+        version: 9.7.0(@types/react@19.2.18)(react-dom@19.2.8(react@19.2.8))(react@19.2.8)(three@0.185.1)
+      '@react-three/postprocessing':
+        specifier: ^3.0.4
+        version: 3.0.4(@react-three/fiber@9.7.0(@types/react@19.2.18)(react-dom@19.2.8(react@19.2.8))(react@19.2.8)(three@0.185.1))(@types/three@0.185.4)(react@19.2.8)(three@0.185.1)
+      '@tts/bgm':
+        specifier: workspace:*
+        version: link:../bgm
+      '@tts/http':
+        specifier: workspace:*
+        version: link:../http
+      '@tts/mesh':
+        specifier: workspace:*
+        version: link:../mesh
+      react:
+        specifier: ^19.2.8
+        version: 19.2.8
+      three:
+        specifier: ^0.185.1
+        version: 0.185.1
+      zustand:
+        specifier: ^5.0.14
+        version: 5.0.14(@types/react@19.2.18)(react@19.2.8)(use-sync-external-store@1.6.0(react@19.2.8))
+    devDependencies:
+      '@types/react':
+        specifier: ^19.2.18
+        version: 19.2.18
+      '@types/three':
+        specifier: ^0.185.4
+        version: 0.185.4
+      typescript:
+        specifier: ^5.7.2
+        version: 5.9.3
+      vitest:
+        specifier: ^4.1.10
+        version: 4.1.10(@types/node@22.20.1)(vite@8.2.1(@types/node@22.20.1)(esbuild@0.28.1)(jiti@2.7.0)(tsx@4.23.11)(yaml@2.9.0))
+
   packages/tts:
     dependencies:
       '@tts/shared':