.

frontend/src/scripts/objects/game-object-container.ts

@@ -1,6 +1,7 @@
 import { Renderer } from 'sdf-2d';
 import {
   Circle,
+  CharacterBase,
   CommandExecutors,
   CommandReceiver,
   CreateObjectsCommand,
@@ -21,6 +22,10 @@ import { CharacterView } from './types/character-view';
 import { PlanetView } from './types/planet-view';
 import { View } from './view';
 
+// Keep enough history for interpolation, without retaining a background tab's entire session.
+const deferredHistorySeconds = 0.5;
+const persistentRemoteCalls = new Set(['setKillCount', 'setLight', 'setContested']);
+
 export class GameObjectContainer extends CommandReceiver {
   public player?: CharacterView;
   public readonly camera: Camera;
@@ -28,6 +33,7 @@ export class GameObjectContainer extends CommandReceiver {
 
   private objects: Map<Id, View> = new Map();
   private wasLocalPlayerAlive = false;
+  private lastStepAtMs = performance.now();
 
   // Creates and deletes take effect on the render timeline, not on arrival.
   private visibleFrom = new Map<Id, number>();
@@ -67,6 +73,7 @@ export class GameObjectContainer extends CommandReceiver {
     [PropertyUpdatesForObjects.name]: (c: PropertyUpdatesForObjects) => {
       serverTimeline.onSnapshot(c.timestamp);
       this.stampPending(c.timestamp);
+      this.pruneDeferred(c.timestamp - deferredHistorySeconds);
       c.updates.forEach((u) => {
         const object = this.objects.get(u.id);
         u.updates.forEach((au) => object?.updateProperty?.(au));
@@ -96,6 +103,7 @@ export class GameObjectContainer extends CommandReceiver {
     this.awaitingDeleteStamp = [];
     this.remoteCalls = [];
     this.wasLocalPlayerAlive = false;
+    this.lastStepAtMs = performance.now();
   }
 
   public get localPlayer(): CharacterView | undefined {
@@ -104,6 +112,12 @@ export class GameObjectContainer extends CommandReceiver {
 
   public step(deltaTimeInSeconds: number) {
     this.stampPending(serverTimeline.snapshotTime);
+    const nowMs = performance.now();
+    const resumed = nowMs - this.lastStepAtMs > deferredHistorySeconds * 1000;
+    this.lastStepAtMs = nowMs;
+    this.pruneDeferred(
+      serverTimeline.renderTime - (resumed ? 0 : deferredHistorySeconds),
+    );
     this.retireDueObjects();
     this.remoteCalls = this.remoteCalls.filter(({ object, calls, at }) => {
       if (this.objects.get(object.id) !== object) {
@@ -166,8 +180,25 @@ export class GameObjectContainer extends CommandReceiver {
     }
   }
 
-  private retireDueObjects() {
-    const renderTime = serverTimeline.renderTime;
+  private pruneDeferred(cutoff: number) {
+    this.retireDueObjects(cutoff);
+    this.remoteCalls = this.remoteCalls.filter(({ object, calls, at }) => {
+      if (at === undefined || at > cutoff) {
+        return true;
+      }
+      for (const call of calls) {
+        if (call.functionName === 'setHealth' && object instanceof CharacterBase) {
+          // The view's health setter also plays hit feedback; expired damage is state only.
+          object.health = call.args[0];
+        } else if (persistentRemoteCalls.has(call.functionName)) {
+          object.processRemoteCalls([call]);
+        }
+      }
+      return false;
+    });
+  }
+
+  private retireDueObjects(renderTime = serverTimeline.renderTime) {
     for (const [id, at] of this.deleteAt) {
       if (renderTime >= at) {
         this.deleteObject(id);
@@ -205,8 +236,13 @@ export class GameObjectContainer extends CommandReceiver {
   }
 
   private deleteObject(id: Id) {
-    this.objects.get(id)?.beforeDestroy?.();
+    const object = this.objects.get(id);
+    object?.beforeDestroy?.();
     this.objects.delete(id);
+    this.remoteCalls = this.remoteCalls.filter((call) => call.object !== object);
+    if (this.player === object) {
+      this.player = undefined;
+    }
     this.planets = this.planets.filter((p) => p.id !== id);
     this.visibleFrom.delete(id);
     this.deleteAt.delete(id);

test/suspended-rendering.test.ts

@@ -0,0 +1,278 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import {
+  CharacterBase,
+  CharacterTeam,
+  Circle,
+  CreateObjectsCommand,
+  DeleteObjectsCommand,
+  GameObject,
+  PropertyUpdatesForObjects,
+  RemoteCall,
+  RemoteCallsForObject,
+  RemoteCallsForObjects,
+} from '../frontend/node_modules/shared';
+import { GameObjectContainer } from '../frontend/src/scripts/objects/game-object-container';
+import { PlanetView } from '../frontend/src/scripts/objects/types/planet-view';
+import { serverTimeline } from '../frontend/src/scripts/helper/server-timeline';
+
+vi.mock('../frontend/src/scripts/objects/types/camera', () => ({
+  Camera: class {
+    draw() {}
+    follow() {}
+  },
+}));
+vi.mock('../frontend/src/scripts/objects/types/planet-view', () => ({
+  PlanetView: class {
+    beforeDestroy = vi.fn();
+    render = vi.fn();
+    processRemoteCalls = vi.fn();
+    step() {}
+    constructor(public id: number) {}
+  },
+}));
+vi.mock('../frontend/src/scripts/sound-handler', () => ({
+  SoundHandler: { play: vi.fn() },
+  Sounds: {},
+}));
+vi.mock('../frontend/src/scripts/feedback-hud', () => ({ FeedbackHud: {} }));
+
+let nowMs = 0;
+beforeEach(() => {
+  nowMs = 0;
+  vi.spyOn(performance, 'now').mockImplementation(() => nowMs);
+  serverTimeline.reset();
+});
+afterEach(() => vi.restoreAllMocks());
+
+function character(id = 1) {
+  const pose = new Circle([0, 0], 10);
+  const object = new CharacterBase(
+    id,
+    'Remote player',
+    0,
+    0,
+    CharacterTeam.red,
+    100,
+    pose,
+    pose,
+    pose,
+  );
+  return Object.assign(object, {
+    step: vi.fn(),
+    render: vi.fn(),
+    beforeDestroy: vi.fn(),
+    // A health setter also represents damage sound/flash feedback in CharacterView.
+    setHealth: vi.fn((health: number) => (object.health = health)),
+    onShoot: vi.fn(),
+    onDie: vi.fn(),
+  });
+}
+
+function calls(
+  container: GameObjectContainer,
+  id: number,
+  ...entries: Array<[string, ...unknown[]]>
+) {
+  container.handleCommand(
+    new RemoteCallsForObjects([
+      new RemoteCallsForObject(
+        id,
+        entries.map(([name, ...args]) => new RemoteCall(name, args)),
+      ),
+    ]),
+  );
+}
+
+function snapshot(container: GameObjectContainer, timestamp: number) {
+  nowMs = (timestamp - 5) * 1000;
+  container.handleCommand(new PropertyUpdatesForObjects([], timestamp));
+}
+
+function retained(container: GameObjectContainer) {
+  return container as unknown as {
+    objects: Map<number, unknown>;
+    deleteAt: Map<number, number>;
+    remoteCalls: Array<{ object: unknown }>;
+  };
+}
+
+describe('suspended rendering', () => {
+  it('bounds deleted views and effect batches as snapshots arrive without frames', () => {
+    const container = new GameObjectContainer({} as never);
+    const survivor = character();
+    container.handleCommand(new CreateObjectsCommand([survivor]));
+    const deleted: PlanetView[] = [];
+
+    for (let i = 0; i < 1000; i++) {
+      const object = new PlanetView(i + 100, []);
+      deleted.push(object);
+      container.handleCommand(new CreateObjectsCommand([object]));
+      calls(container, survivor.id, ['onShoot', 40]);
+      container.handleCommand(new DeleteObjectsCommand([object.id]));
+      snapshot(container, 5 + i * 0.04);
+
+      expect(container.planets.length).toBeLessThanOrEqual(15);
+      expect(retained(container).objects.size).toBeLessThanOrEqual(16);
+      expect(retained(container).deleteAt.size).toBeLessThanOrEqual(15);
+      expect(retained(container).remoteCalls.length).toBeLessThanOrEqual(15);
+    }
+
+    expect(deleted[0].beforeDestroy).toHaveBeenCalledOnce();
+    expect(deleted[984].beforeDestroy).toHaveBeenCalledOnce();
+    expect(survivor.onShoot).not.toHaveBeenCalled();
+
+    serverTimeline.step(0);
+    container.step(0);
+    expect(survivor.onShoot).not.toHaveBeenCalled();
+    expect(retained(container).remoteCalls.length).toBeLessThanOrEqual(3);
+
+    // With no additional effects, subsequent snapshots retire the entire old tail.
+    snapshot(container, 46);
+    expect(container.planets).toHaveLength(0);
+    expect(retained(container).objects.size).toBe(1);
+    expect(retained(container).deleteAt.size).toBe(0);
+    expect(retained(container).remoteCalls).toHaveLength(0);
+    serverTimeline.step(0);
+    container.step(0);
+    expect(survivor.onShoot).not.toHaveBeenCalled();
+  });
+
+  it('preserves expired state silently and applies fresh health feedback in order', () => {
+    const container = new GameObjectContainer({} as never);
+    const object = character();
+    container.handleCommand(new CreateObjectsCommand([object]));
+    calls(container, object.id, ['setHealth', 80], ['setKillCount', 1], ['onShoot', 40]);
+    snapshot(container, 5);
+    calls(container, object.id, ['setHealth', 60], ['setKillCount', 2], ['onDie']);
+    snapshot(container, 5.04);
+    snapshot(container, 5.6);
+
+    expect(object.health).toBe(60);
+    expect(object.killCount).toBe(2);
+    expect(object.setHealth).not.toHaveBeenCalled();
+    expect(object.onShoot).not.toHaveBeenCalled();
+    expect(object.onDie).not.toHaveBeenCalled();
+
+    calls(container, object.id, ['setHealth', 40], ['setKillCount', 3], ['onShoot', 50]);
+    snapshot(container, 5.7);
+    serverTimeline.step(0);
+    container.step(0);
+    expect(object.health).toBe(60);
+    expect(object.setHealth).not.toHaveBeenCalled();
+
+    nowMs += 110;
+    serverTimeline.step(0.11);
+    container.step(0);
+    expect(object.health).toBe(40);
+    expect(object.killCount).toBe(3);
+    expect(object.setHealth).toHaveBeenCalledExactlyOnceWith(40);
+    expect(object.onShoot).toHaveBeenCalledExactlyOnceWith(50);
+    expect(object.onDie).not.toHaveBeenCalled();
+  });
+
+  it('preserves final light and contested state while discarding transient planet effects', () => {
+    const container = new GameObjectContainer({} as never);
+    const object = Object.assign(new (class extends GameObject {})(1), {
+      contested: false,
+      lightness: 0,
+      color: [0, 0, 0],
+      step() {},
+      render() {},
+      setContested(value: boolean) {
+        this.contested = value;
+      },
+      setLight(color: number[], lightness: number) {
+        this.color = color;
+        this.lightness = lightness;
+      },
+      onFlipped: vi.fn(),
+      generatedPoints: vi.fn(),
+    });
+    container.handleCommand(new CreateObjectsCommand([object]));
+    calls(
+      container,
+      object.id,
+      ['setContested', true],
+      ['setLight', [1, 0, 0], 2],
+      ['onFlipped', CharacterTeam.red],
+      ['generatedPoints', 10],
+    );
+    snapshot(container, 5);
+    calls(
+      container,
+      object.id,
+      ['setContested', false],
+      ['setLight', [0, 0, 1], 3],
+      ['onFlipped', CharacterTeam.blue],
+      ['generatedPoints', 20],
+    );
+    snapshot(container, 5.04);
+    snapshot(container, 6);
+
+    expect(object.contested).toBe(false);
+    expect(object.color).toEqual([0, 0, 1]);
+    expect(object.lightness).toBe(3);
+    expect(object.onFlipped).not.toHaveBeenCalled();
+    expect(object.generatedPoints).not.toHaveBeenCalled();
+    expect(retained(container).remoteCalls).toHaveLength(0);
+  });
+
+  it('releases effect references immediately when a paused view is replaced', () => {
+    const container = new GameObjectContainer({} as never);
+    let object = character();
+    container.handleCommand(new CreateObjectsCommand([object]));
+    snapshot(container, 5);
+
+    for (let i = 0; i < 100; i++) {
+      calls(container, object.id, ['onShoot', 40]);
+      container.handleCommand(new DeleteObjectsCommand([object.id]));
+      const replacement = character(object.id);
+      container.handleCommand(new CreateObjectsCommand([replacement]));
+      expect(object.beforeDestroy).toHaveBeenCalledOnce();
+      expect(retained(container).remoteCalls).toHaveLength(0);
+      expect(retained(container).objects.get(object.id)).toBe(replacement);
+      object = replacement;
+    }
+
+    snapshot(container, 5.04);
+    nowMs += 200;
+    serverTimeline.step(0.2);
+    container.step(0);
+    expect(object.beforeDestroy).not.toHaveBeenCalled();
+  });
+
+  it('expires the last queued effects on resume even when snapshots also stopped', () => {
+    const container = new GameObjectContainer({} as never);
+    const object = character();
+    container.handleCommand(new CreateObjectsCommand([object]));
+    calls(container, object.id, ['setHealth', 20], ['setKillCount', 4], ['onShoot', 40]);
+    snapshot(container, 5);
+
+    nowMs += 10_000;
+    serverTimeline.step(10);
+    container.step(10);
+
+    expect(object.health).toBe(20);
+    expect(object.killCount).toBe(4);
+    expect(object.setHealth).not.toHaveBeenCalled();
+    expect(object.onShoot).not.toHaveBeenCalled();
+    expect(retained(container).remoteCalls).toHaveLength(0);
+  });
+
+  it('releases a deleted local player reference without waiting for a frame', () => {
+    const container = new GameObjectContainer({} as never);
+    const object = character();
+    container.handleCommand(new CreateObjectsCommand([object]));
+    container.player = object as never;
+    snapshot(container, 5);
+    container.handleCommand(new DeleteObjectsCommand([object.id]));
+    snapshot(container, 5.04);
+    expect(container.localPlayer).toBe(object);
+
+    snapshot(container, 6);
+    expect(object.beforeDestroy).toHaveBeenCalledOnce();
+    expect(container.player).toBeUndefined();
+    expect(container.localPlayer).toBeUndefined();
+    expect(retained(container).objects.size).toBe(0);
+  });
+});