Three JS Multiplayer Game Demo

Welcome to Notblox! This project showcases a simple multiplayer game engine built with Three.js and TypeScript, featuring an Entity Component System (ECS) for efficient network synchronization and utilizing Rapier.js for physics.

Online Demo

Demo link: NotBlox.online
Hosted on a European server. Note: There is no client-side prediction, so the game may feel laggy if you're far from the server.

Videos :

Car https://www.youtube.com/watch?v=7eSYb6jKOV0
Football https://www.youtube.com/watch?v=tZlNKU_buCQ

Controls

W : Forward
S : Backward
A : Left
D : Right
Space : Jump
Mouse Left click : Rotate screen
E : Interact

Features

Multiplayer
Only TypeScript
3D Physics (Rapier.js)
Vanilla Three.js
Server Authoritative
ECS (Entity Component System) with Network Sync (NetworkComponent)
~Delta Compression~ (needs rework)
Interpolation
Fast to load (small assets)
Run on low end devices : My Three.JS Performance Guide
Shared code between server and client (useful for component replication)
Trimesh Collider
Cars

Why ?

Browser games are fun, but most of them are Unity WebGL exports that take a long time to load. I wanted to create a simple multiplayer game engine using Three.js and my own ECS. This project has in mind to be a simple and fast game engine that can be used to create simple multiplayer games with the modularity of ECS.

Multiplayer GTA-like ?

I'm thinking about creating a GTA-like game with this engine. It would be a simple game with a city, cars, and players. The game would be server-authoritative, and the server would be able to spawn cars, NPCs, and other entities. The game would be a simple sandbox game where players can interact with each other and the environment. Inspiration : https://github.com/swift502/Sketchbook

Demo (Click on the images to see the video)

How to run locally

Prerequisites:

Node.js v24+ — required by uWebSockets.js. Use nvm to manage versions.
pnpm — this is a monorepo. Install it with npm i -g pnpm if you don't have it.

Clone the repo

git clone https://github.com/iErcann/Notblox.git
cd Notblox

Install all packages

pnpm install

Run everything (back + front + shared watch)

pnpm run dev

Or run individually

pnpm run dev:back    # game server on ws://localhost:8001
pnpm run dev:front   # Next.js on http://localhost:4000

Go on your browser to http://localhost:4000/play/test

Backend Configuration (Game Server)

The backend can be configured through environment variables in ./back/.env:

Local dev mode

NODE_ENV=development
GAME_TICKRATE=20 # Game tickrate in Hz (20Hz = 50ms)
GAME_SCRIPT=defaultScript.ts # Script source file in back/src/scripts/

# Commented in dev mode :
# FRONTEND_URL=https://www.notblox.online # Only accept connections from this URL

In production

NODE_ENV=production
GAME_TICKRATE=20 # Game tickrate in Hz (20Hz = 50ms)
GAME_SCRIPT=defaultScript.ts # Script source file in back/src/scripts/

# To prevent hijacking
FRONTEND_URL=https://www.notblox.online

# To get WSS, set your path:
SSL_KEY_FILE=/etc/letsencrypt/live/npm-3/privkey.pem
SSL_CERT_FILE=/etc/letsencrypt/live/npm-3/cert.pem

Game Scripts

The GAME_SCRIPT system allows for modular gameplay modes similar to Garry's Mod's LUA scripts.

Scripts live in back/src/scripts/ and are plain TypeScript source files loaded at runtime by tsx — no compilation step needed. The Docker image is built once; scripts can be swapped via a volume mount without ever rebuilding.

| Script | Description | | ----------------------- | ------------------------------------------------------------------- | | defaultScript.ts | Sandbox world: cars, physics cubes, a trampoline, a football | | footballScript.ts | 2-team football match with score, goals, and a kick mechanic | | parkourScript.ts | Obby-style obstacle course with checkpoints | | petSimulatorScript.ts | Pet simulator: hatch eggs, collect pets, leaderboard, coin triggers |

How it works:

GAME_SCRIPT in .env points to the source filename (e.g. defaultScript.ts)
At startup, sandbox.ts dynamically imports the script via tsx — TypeScript is stripped/transformed on the fly by Node's tsx loader

Swapping scripts without rebuilding:

# Mount a local scripts folder over the one baked into the image
docker run \
  -v ./my-scripts:/app/back/src/scripts \
  -e GAME_SCRIPT=myGame.ts \
  ghcr.io/iercann/notblox-game-server:latest

Adding a new game mode:

Create back/src/scripts/myGame.ts — import ECS entities/components as needed
Set GAME_SCRIPT=myGame.ts in .env
Run pnpm run dev:back

Tickrate Configuration

The GAME_TICKRATE setting controls how frequently the server updates game state:

| Tickrate | Use Case | Description | Server CPU Usage | | ---------- | --------------------- | -------------------------------------------------------------- | ---------------- | | 60 ticks/s | Vehicle/Physics-heavy | Smooth physics interactions, highest precision vehicle control | High | | 40 ticks/s | Mixed Gameplay | Good physics interactions, balanced vehicle control | Medium | | 20 ticks/s | Standard Gameplay | Good balance of responsiveness and performance | Low |

Performance Considerations:

Higher tickrates = smoother gameplay but increased:
- Server CPU usage
- Network bandwidth
- Client-server messages
Choose based on your game's requirements and server capacity
View Stress Test (20 ticks/s)

Front end Configuration

To configure the front end, set the NEXT_PUBLIC_SERVER_URL environment variable in your .env.local file:

# Development
NEXT_PUBLIC_SERVER_URL=ws://localhost

# Production (SSL Required)
# NEXT_PUBLIC_SERVER_URL=wss://back.notblox.online

How to change the map

Maps are GLB/GLTF files. The back-end approximates a Trimesh Collider based on the map, which is rendered on the client.

To change the map, update the URL in back/src/scripts/defaultScript.ts:

new MapWorld('https://notbloxo.fra1.cdn.digitaloceanspaces.com/Notblox-Assets/world/TestWorld.glb') // Change this URL to your map

How to Host Your Assets for Free Without a S3 Bucket

You can host your assets for free using GitHub and Githack. Here's how:

Create a repository on GitHub, e.g., Notblox-Assets.
Use Githack to serve your assets via CDN: Setup Githack.

Githack

Then, update the URL in defaultScript.ts:

new MapWorld(
  'https://rawcdn.githack.com/iErcann/Notblox-Assets/d66f6da91bb7f025c90aa9f6eb24b99e997efa38/BasicWorld.glb'
) // Change this URL to your map

How to Point the Map to a Local File (For Testing)

For local testing, place the map .glb under the front/public/assets folder and use:

new MapWorld('http://localhost:4001/BasicWorld.glb')

Make sure to run the front-end with npm run dev to serve the local file.

Blender: How to Export a Map Correctly

Export with Compression

Choose GLB/GLTF export.

Choose GLB/GLTF Export

Activate compression.

Activate Compression

Current Event system (might change!)

Is it better design to store event effects within an Entity itself, or within a system?

If you are using event queues anyway, you can also do them properly. With one global EventManager system which receives all events. Systems can subscribe to events they are interested in and then the EventManager will put those events into their event queues.

Component can also be a NetworkComponent. This means it can be sent over the network to be replicated by the clients.

Shared

// Shared component between client & back
export class ColorComponent extends NetworkComponent {
  constructor(entityId: number, public color: string);
  deserialize(data: SerializedColorComponent);
  serialize(): SerializedColorComponent;
}

Back

The back-end need to pass some events; This is achieved with the event components (example: EventColorComponent) that are only used once per ECS loop and then removed from the EventQueue entity.

// Creating a color change event on the back
EventSystem.addEvent(new ColorEve

NotBlox

Install / Use

README