don't update controllable entities on the client

client/src/JumpStorm.ts

@@ -8,7 +8,8 @@ import {
   Physics,
   Input,
   Collision,
-  NetworkUpdate
+  NetworkUpdate,
+  SystemNames
 } from '@engine/systems';
 import {
   type MessageQueueProvider,
@@ -20,6 +21,7 @@ import {
   type EntityUpdateBody
 } from '@engine/network';
 import { stringify, parse } from '@engine/utils';
+import { ComponentNames, Control, NetworkUpdateable } from '@engine/components';
 
 class ClientMessageProcessor implements MessageProcessor {
   private game: Game;
@@ -32,11 +34,27 @@ class ClientMessageProcessor implements MessageProcessor {
     switch (message.type) {
       case MessageType.NEW_ENTITIES:
         const entityAdditions = message.body as unknown as EntityAddBody[];
-        entityAdditions.forEach((addBody) =>
-          this.game.addEntity(
-            Entity.from(addBody.entityName, addBody.id, addBody.args)
-          )
+        entityAdditions.forEach((addBody) => {
+          const entity = Entity.from(
+            addBody.entityName,
+            addBody.id,
+            addBody.args
           );
+          if (entity.hasComponent(ComponentNames.Control)) {
+            const clientId = this.game.getSystem<Input>(
+              SystemNames.Input
+            ).clientId;
+            const control = entity.getComponent<Control>(
+              ComponentNames.Control
+            );
+
+            if (control.controllableBy === clientId) {
+              entity.addComponent(new NetworkUpdateable());
+            }
+          }
+
+          this.game.addEntity(entity);
+        });
         break;
       case MessageType.REMOVE_ENTITIES:
         const ids = message.body as unknown as string[];
@@ -44,9 +62,22 @@ class ClientMessageProcessor implements MessageProcessor {
         break;
       case MessageType.UPDATE_ENTITIES:
         const entityUpdates = message.body as unknown as EntityUpdateBody[];
-        entityUpdates.forEach(
-          ({ id, args }) => this.game.getEntity(id)?.setFrom(args)
+        entityUpdates.forEach(({ id, args }) => {
+          const entity = this.game.getEntity(id);
+          if (!entity) return;
+          if (entity && entity.hasComponent(ComponentNames.Control)) {
+            const clientId = this.game.getSystem<Input>(
+              SystemNames.Input
+            ).clientId;
+            const control = entity.getComponent<Control>(
+              ComponentNames.Control
             );
+
+            // don't listen to entities which we control
+            if (control.controllableBy == clientId) return;
+          }
+          entity.setFrom(args);
+        });
         break;
       default:
         break;
@@ -131,6 +162,7 @@ export class JumpStorm {
     const grid = new Grid();
 
     [
+      new Physics(),
       new NetworkUpdate(
         clientSocketMessageQueueProvider,
         clientSocketMessagePublisher,
@@ -138,7 +170,6 @@ export class JumpStorm {
       ),
       inputSystem,
       new FacingDirection(),
-      new Physics(),
       new Collision(grid),
       new WallBounds(),
       new Render(ctx)

client/vite.config.ts

@@ -5,10 +5,9 @@ import { fileURLToPath, URL } from 'node:url';
 // https://vitejs.dev/config/
 export default defineConfig({
   server: {
-    host: '0.0.0.0',
     proxy: {
       '/api': {
-        target: 'http://10.0.0.237:8080',
+        target: 'http://localhost:8080',
         ws: true,
         rewrite: (path) => path.replace(/^\/api/, '')
       }

engine/Game.ts

@@ -56,8 +56,8 @@ export class Game {
     this.systems.set(system.name, system);
   }
 
-  public getSystem(name: string): System | undefined {
-    return this.systems.get(name);
+  public getSystem<T>(name: string): T {
+    return this.systems.get(name) as unknown as T;
   }
 
   public doGameLoop(timeStamp: number) {

engine/components/Control.ts

@@ -3,16 +3,17 @@ import { Component, ComponentNames, Velocity } from '.';
 export class Control extends Component {
   public controlVelocityComponent: Velocity;
   public controllableBy: string;
-  public isControllable: boolean; // computed each update in the input system
+  public isControllable?: boolean; // updated by the input system
 
   constructor(
     controllableBy: string,
-    controlVelocityComponent: Velocity = new Velocity()
+    controlVelocityComponent: Velocity = new Velocity(),
+    isControllable?: boolean
   ) {
     super(ComponentNames.Control);
 
     this.controllableBy = controllableBy;
+    this.isControllable = isControllable;
     this.controlVelocityComponent = controlVelocityComponent;
-    this.isControllable = false;
   }
 }

engine/entities/Player.ts

@@ -82,7 +82,7 @@ export class Player extends Entity {
   }
 
   public setFrom(args: Record<string, any>) {
-    const { control, velocity, forces, boundingBox } = args;
+    const { control, forces, velocity, boundingBox } = args;
 
     let center = boundingBox.center;
 
@@ -92,7 +92,8 @@ export class Player extends Entity {
     const distance = Math.sqrt(
       Math.pow(center.y - myCenter.y, 2) + Math.pow(center.x - myCenter.x, 2)
     );
-    if (distance < 30) center = myCenter;
+    const clientServerPredictionCenterThreshold = 30;
+    if (distance < clientServerPredictionCenterThreshold) center = myCenter;
 
     [
       Object.assign(new Control(control.controllableBy), control),

engine/structures/RefreshingCollisionFinderBehavior.ts

@@ -11,4 +11,5 @@ export interface RefreshingCollisionFinderBehavior {
   insert(boxedEntry: BoxedEntry): void;
   getNeighborIds(boxedEntry: BoxedEntry): Set<string>;
   setTopLeft(topLeft: Coord2D): void;
+  setDimension(dimension: Dimension2D): void;
 }

engine/systems/NetworkUpdate.ts

@@ -8,13 +8,16 @@ import {
   MessageType,
   EntityUpdateBody
 } from '../network';
+import { stringify } from '../utils';
+
+type EntityUpdateInfo = { timer: number; hash: string };
 
 export class NetworkUpdate extends System {
   private queueProvider: MessageQueueProvider;
   private publisher: MessagePublisher;
   private messageProcessor: MessageProcessor;
 
-  private entityUpdateTimers: Map<string, number>;
+  private entityUpdateInfo: Map<string, EntityUpdateInfo>;
 
   constructor(
     queueProvider: MessageQueueProvider,
@@ -27,10 +30,20 @@ export class NetworkUpdate extends System {
     this.publisher = publisher;
     this.messageProcessor = messageProcessor;
 
-    this.entityUpdateTimers = new Map();
+    this.entityUpdateInfo = new Map();
   }
 
   public update(dt: number, game: Game) {
+    // 0. remove unnecessary info for removed entities
+    const networkUpdateableEntities = game.componentEntities.get(
+      ComponentNames.NetworkUpdateable
+    );
+    for (const entityId of this.entityUpdateInfo.keys()) {
+      if (!networkUpdateableEntities?.has(entityId)) {
+        this.entityUpdateInfo.delete(entityId);
+      }
+    }
+
     // 1. process new messages
     this.queueProvider
       .getNewMessages()
@@ -39,24 +52,41 @@ export class NetworkUpdate extends System {
 
     // 2. send entity updates
     const updateMessages: EntityUpdateBody[] = [];
+
+    // todo: figure out if we can use the controllable component to determine if we should publish an update
     game.forEachEntityWithComponent(
       ComponentNames.NetworkUpdateable,
       (entity) => {
-        let timer = this.entityUpdateTimers.get(entity.id) ?? dt;
-        timer -= dt;
-        this.entityUpdateTimers.set(entity.id, timer);
+        const newHash = stringify(entity.serialize());
+        let updateInfo: EntityUpdateInfo = this.entityUpdateInfo.get(
+          entity.id
+        ) ?? {
+          timer: this.getNextUpdateTimeMs(),
+          hash: newHash
+        };
 
-        if (timer > 0) return;
-        this.entityUpdateTimers.set(entity.id, this.getNextUpdateTimeMs());
+        // update timer
+        updateInfo.timer -= dt;
+        this.entityUpdateInfo.set(entity.id, updateInfo);
+        if (updateInfo.timer > 0) return;
+        updateInfo.timer = this.getNextUpdateTimeMs();
+        this.entityUpdateInfo.set(entity.id, updateInfo);
+
+        // maybe update if hash is not consitent
+        if (updateInfo.hash == newHash) {
+          return;
+        }
+        updateInfo.hash = newHash;
+        this.entityUpdateInfo.set(entity.id, updateInfo);
 
-        if (entity.hasComponent(ComponentNames.NetworkUpdateable)) {
         updateMessages.push({
           id: entity.id,
           args: entity.serialize()
         });
       }
-      }
     );
+
+    if (updateMessages.length)
       this.publisher.addMessage({
         type: MessageType.UPDATE_ENTITIES,
         body: updateMessages
@@ -67,6 +97,6 @@ export class NetworkUpdate extends System {
   }
 
   private getNextUpdateTimeMs() {
-    return Math.random() * 70 + 50;
+    return Math.random() * 30 + 50;
   }
 }

engine/systems/Physics.ts

@@ -11,7 +11,7 @@ import {
   Control
 } from '../components';
 import { PhysicsConstants } from '../config';
-import type { Force2D, Velocity2D } from '../interfaces';
+import type { Force2D } from '../interfaces';
 import { Game } from '../Game';
 
 export class Physics extends System {
@@ -98,7 +98,7 @@ export class Physics extends System {
           ? 360 + boundingBox.rotation
           : boundingBox.rotation) % 360;
 
-      // clear the control velocity
+      // clear the control velocity if and only if we are controlling
       if (control && control.isControllable) {
         control.controlVelocityComponent = new Velocity();
       }

engine/utils/coding.ts

@@ -9,6 +9,18 @@ const replacer = (_key: any, value: any) => {
   }
 };
 
+const sortObj = (obj: any): any =>
+  obj === null || typeof obj !== 'object'
+    ? obj
+    : Array.isArray(obj)
+    ? obj.map(sortObj)
+    : Object.assign(
+        {},
+        ...Object.entries(obj)
+          .sort(([keyA], [keyB]) => keyA.localeCompare(keyB))
+          .map(([k, v]) => ({ [k]: sortObj(v) }))
+      );
+
 const reviver = (_key: any, value: any) => {
   if (typeof value === 'object' && value !== null) {
     if (value.dataType === 'Map') {
@@ -18,8 +30,9 @@ const reviver = (_key: any, value: any) => {
   return value;
 };
 
+// "deterministic" stringify
 export const stringify = (obj: any) => {
-  return JSON.stringify(obj, replacer);
+  return JSON.stringify(sortObj(obj), replacer);
 };
 
 export const parse = <T>(str: string) => {

server/src/constants.ts

@@ -1,6 +1,6 @@
 export namespace Constants {
   export const SERVER_PORT = 8080;
-  export const SERVER_TICK_RATE = (1 / 60) * 1000;
+  export const SERVER_TICK_RATE = (1 / 120) * 1000;
   export const GAME_TOPIC = 'game';
   export const MAX_PLAYERS = 8;
 }

server/src/main.ts

@@ -30,9 +30,9 @@ const server = new GameServer(
 );
 
 [
+  new Physics(),
   new SessionInputSystem(sessionManager),
   new NetworkUpdate(messageReceiver, messagePublisher, messageProcessor),
-  new Physics(),
   new Collision(new Grid()),
   new WallBounds()
 ].forEach((system) => game.addSystem(system));
@@ -44,9 +44,9 @@ floor.addComponent(
   new BoundingBox(
     {
       x: Miscellaneous.WIDTH / 2,
-      y: Miscellaneous.HEIGHT + floorHeight / 2
+      y: Miscellaneous.HEIGHT - floorHeight / 2
     },
-    { width: Miscellaneous.WIDTH, height: floorHeight }
+    { width: Miscellaneous.WIDTH / 2, height: floorHeight }
   )
 );
 game.addEntity(floor);

server/src/network/MessageProcessor.ts

@@ -29,8 +29,16 @@ export class ServerMessageProcessor implements MessageProcessor {
         session?.inputSystem.keyReleased(message.body as string);
         break;
       }
-      default:
+      case MessageType.UPDATE_ENTITIES: {
+        const entityUpdates = message.body as unknown as EntityUpdateBody[];
+        entityUpdates.forEach(({ id, args }) =>
+          this.game.getEntity(id)?.setFrom(args)
+        );
+        break;
+      }
+      default: {
         break;
       }
     }
   }
+}

server/src/network/SessionInputSystem.ts

@@ -1,7 +1,7 @@
 import { Game } from '@engine/Game';
 import { SessionManager } from '.';
 import { System } from '@engine/systems';
-import { BoundingBox, ComponentNames, Control } from '@engine/components';
+import { ComponentNames } from '@engine/components';
 
 export class SessionInputSystem extends System {
   private sessionManager: SessionManager;