SmartLoop

Zero-dependency utility for running JS up to 3 parallel update methods at configurable rate.

📋 Changelog · 📢 Issues and requests

Motivation

Needed zero-dependency isomorphic game loop allowing running render and simulation updates at different configurable rate and support for deterministic lockstep networking.

Features

• Written in TypeScript (includes definitions)
• Created using ES6 generators
• Can be run in both browser or Node
• Electron and NWJS friendly
• Supports up to 3 separate update method types render(), update(), fixedUpdate()
  • Maximum 2 update methods when in Node render()
• Exposes render() method build on the top of requestAnimationFrame()
• Uses setImmediate() and setTimeout() when in Node

Usage

const update = () => { /* render code */ }
const fixedUpdate = () => { /* physics code */ }

const loop = new SmartLoop({ rate: 60, update, fixedRate: 30, fixedUpdate  })

loop.start()

setTimeout(() => loop.pause(), 2000)
setTimeout(() => loop.resume(), 3000)

References

Good reads

• High Resolution Time from w3.org
• Game timers: Issues and solutions.
• Fix Your Timestep! by Glenn Fiedler
• Game loop from Game Programming Patterns books
• A Modern C++ Game Loop Template (MIT) on Reddit

GDC Talks

• GDC - Networking for Physics by Glenn Fiedler
• 8 Frames in 16ms: Rollback Networking in Mortal Kombat and Injustice 2 by Michael Stallone

Libraries

• node-microtime (benchmark gist)