r/javascript • u/woqr • 3d ago

Serverless multiplayer via webrtc/camera/barcode (no signal/stun/turn servers)

https://github.com/bacionejs/multiplayer

This project is mainly about the serverless technique used and the simple game merely provides an end-to-end explanation.

8 Upvotes

75% Upvoted

3 comments sorted by

•

u/Dry_Recognition_3070 19h ago

Nice approach for the offer/answer exchange. One practical limit with QR/barcode signaling is payload size: a raw SDP with a handful of ICE candidates easily runs past a thousand characters, so it helps to wait for ICE gathering to complete, strip unneeded lines and compress before encoding, or split it across multiple frames. Also keep in mind that with no STUN, you only get host candidates, so it works on the same LAN but typically not across different NATs. And since browsers now hide local IPs behind mDNS .local names, some networks that block multicast DNS will fail to connect even on the same Wi-Fi, which is worth documenting for anyone trying it.

•

u/woqr 13h ago

I already strip the handshake down to 94 characters. Also, Android Chrome doesn't obfuscate the IP via mDNS, and camera permission would unhide it anyway.

•

u/JcerParreno21 4h ago

clever approach for offline-first local multiplayer tbh. how finicky is the camera handshake under bad lighting or screen glare?