feat: add render graph driven renderer architecture

Amp-Thread-ID: https://ampcode.com/threads/T-019f9d91-77c1-7206-a60f-ed6554ce92ab

Co-authored-by: Heaust Azure <heaust.azure@gmail.com>

vendor/fxnode/test/render-scheduler.test.ts

@@ -0,0 +1,83 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import { DirtyReason, RenderScheduler, requestViewInvalidations } from "@lib/worker/render-scheduler.js";
+
+test("atlas cleanup invalidations request worker viewport repaints", () => {
+  const requests: Array<readonly [number, DirtyReason]> = [];
+  const views = new Map([
+    ["a", { scheduler: { request: (id: number, reason: DirtyReason) => requests.push([id, reason]) } }],
+  ]);
+  requestViewInvalidations(["missing", "a"], views);
+  assert.deepEqual(requests, [[0, DirtyReason.Viewport]]);
+});
+
+test("continuous RAF polls while idle and preserves one-frame backpressure", () => {
+  const callbacks: Array<() => void> = [];
+  const draws: Array<readonly [number, number, number]> = [];
+  let polls = 0;
+  const scheduler = new RenderScheduler(
+    (...args) => draws.push(args),
+    (callback) => callbacks.push(callback),
+  );
+  const tick = () => {
+    const callback = callbacks.shift();
+    assert.ok(callback);
+    callback();
+  };
+
+  scheduler.start(() => polls++);
+  assert.equal(callbacks.length, 1);
+  tick();
+  assert.equal(polls, 1);
+  assert.equal(draws.length, 0);
+  assert.equal(callbacks.length, 1);
+
+  scheduler.request(4, DirtyReason.Preview);
+  tick();
+  assert.deepEqual(draws, [[1, 4, DirtyReason.Preview]]);
+  scheduler.request(5, DirtyReason.Scene);
+  tick();
+  assert.equal(draws.length, 1);
+  scheduler.consumed(99);
+  tick();
+  assert.equal(draws.length, 1);
+  scheduler.consumed(1);
+  tick();
+  assert.deepEqual(draws[1], [2, 5, DirtyReason.Scene]);
+  assert.equal(scheduler.metrics.staleAcks, 1);
+  assert.equal(scheduler.metrics.maxInFlight, 1);
+
+  scheduler.stop();
+  tick();
+  assert.equal(callbacks.length, 0);
+});
+
+test("requests coalesce and only a matching defer retries the same reasons", () => {
+  const callbacks: Array<() => void> = [],
+    draws: Array<readonly [number, number, number]> = [];
+  const scheduler = new RenderScheduler(
+    (...args) => draws.push(args),
+    (callback) => callbacks.push(callback),
+  );
+  const tick = () => callbacks.shift()!();
+  scheduler.start();
+  scheduler.request(2, DirtyReason.Scene);
+  scheduler.request(7, DirtyReason.Selection);
+  tick();
+  assert.deepEqual(draws, [[1, 7, DirtyReason.Scene | DirtyReason.Selection]]);
+
+  scheduler.defer(99, DirtyReason.Camera);
+  tick();
+  assert.equal(draws.length, 1, "a stale defer must not clear the in-flight frame");
+  scheduler.defer(1, DirtyReason.Scene | DirtyReason.Selection);
+  tick();
+  assert.deepEqual(draws[1], [2, 7, DirtyReason.Scene | DirtyReason.Selection]);
+
+  scheduler.consumed(1);
+  tick();
+  assert.equal(draws.length, 2, "a stale ack must not consume the retried frame");
+  scheduler.consumed(2);
+  tick();
+  assert.equal(draws.length, 2);
+  scheduler.stop();
+});