Incheon is a general purpose low latency game server based on Node.JS and Socket.IO

Still in early development. Check back with us soon :P

Features:

• Somewhat opinionated, letting you quickly develop your game without much hassle
• Server to client communication:
  • Communication is all binary
  • A game engine can opt-in to which object properties are transported
• Intelligent sync strategies for lag handling:
  • Client side prediction for player-controlled objects (snap, gradual snap)
  • Update interpolation for non-player objects
• Provides API for dynamic game-world objects
  • game worlds with physics engines (currently only physijs)
  • game worlds with reduced-physics, which track position, velocity, orientation, momentum (linear and angular).

Things to do:

• Allow general messages (not just world updates)
• Input validation (check player can control ship)
• Implement more types of lag compensation
• Optimize what goes over the wire:
  • Only dirty items get sent, with periodic sync
  • Option to specify incremental updates
  • client to server should also be binary
• Recording and replaying sessions
• tests tests tests

Caveats:

• Due to websocket limitations, only TCP and no UDP :(

Architecture

The Step Sequence

The fundamental sequence of each (client-side) step is organized as follows:

1. [clientEngine] process inputs
2. [clientEngine] handle all inbound messages
3. [clientEngine] handle outbound inputs
4. [clientEngine:gameEngine] stepCount++
5. [clientEngine:gameEngine] physicsEngine.step
6. [clientEngine:gameEngine] updateGameWorld: for each object->step
7. [clientEngine] render.draw

Event List

• preStep
• postStep
• objectAdded
• server.playerJoined
• server.playerDisconnected
• server.inputReceived
• client.preStep
• client.postStep