Rebuild core around render graph AST and shared memory

Amp-Thread-ID: https://ampcode.com/threads/T-01a01380-b478-77d0-84a0-102880a5c5ae
Co-authored-by: Heaust Azure <heaust.azure@gmail.com>

addons/mesh-handles/src/index.js

@@ -0,0 +1,67 @@
+const TOKEN = Symbol("yawn mesh handle addon");
+
+/** Creates the optional snapshot/BVH worker used by core's picking protocol. */
+export const createPickingWorker = () => new Worker(
+  new URL("./bvh-worker.js", import.meta.url),
+  { type: "module", name: "yawn-spatial-query" },
+);
+
+/** Conventional mesh/instance objects layered entirely over the Yawn core protocol. */
+export class MeshHandles {
+  #core;
+
+  constructor(core) {
+    this.#core = core;
+  }
+
+  fromImportedScene(result) {
+    if (!result || !Array.isArray(result.meshes)) throw new TypeError("invalid imported scene");
+    return result.meshes.map((mesh) => new Mesh(TOKEN, this.#core, mesh));
+  }
+
+  async pickRay(origin, direction, options) {
+    const result = await this.#core.pickRay(origin, direction, options);
+    return {
+      ...result,
+      hits: result.hits.map((hit) => ({
+        ...hit,
+        instance: new Instance(TOKEN, this.#core, hit.instance),
+      })),
+    };
+  }
+}
+
+export class Mesh {
+  #core; #handle; #defaultInstance; #defaultType;
+
+  constructor(token, core, descriptor) {
+    if (token !== TOKEN) throw new TypeError("Mesh cannot be constructed directly");
+    this.#core = core;
+    this.#handle = Object.freeze([...descriptor.handle]);
+    this.#defaultInstance = new Instance(TOKEN, core, descriptor.defaultInstance);
+    this.#defaultType = Object.freeze([...descriptor.defaultType]);
+  }
+
+  get handle() { return this.#handle; }
+  get defaultInstance() { return this.#defaultInstance; }
+
+  async createInstance(transform, { type = this.#defaultType } = {}) {
+    return new Instance(TOKEN, this.#core, await this.#core.createInstance(this.#handle, transform, { type }));
+  }
+}
+
+export class Instance {
+  #core; #handle; #dead = false;
+
+  constructor(token, core, handle) {
+    if (token !== TOKEN) throw new TypeError("Instance cannot be constructed directly");
+    this.#core = core;
+    this.#handle = Object.freeze([...handle]);
+  }
+
+  get handle() { return this.#handle; }
+  #live() { if (this.#dead) throw new Error("STALE_HANDLE"); }
+  setType(words) { this.#live(); this.#core.setInstanceType(this.#handle, words); }
+  setTransform(transform) { this.#live(); this.#core.setInstanceTransform(this.#handle, transform); }
+  async destroy() { this.#live(); await this.#core.destroyInstance(this.#handle); this.#dead = true; }
+}