DungeonsOfKharadum/MULTIPLAYER_WEBRTC_GUIDE.md

WebRTC Multiplayer Guide

How WebRTC Multiplayer Works

Architecture

Your game now supports two networking modes:

1. ENet (Native builds): Windows/Linux/Mac players connect via IP:Port
2. WebRTC (Web builds): Browser players connect via Room IDs

Important: ENet and WebRTC are NOT compatible with each other!

• PC (ENet) players can only play with other PC (ENet) players
• Browser (WebRTC) players can only play with other Browser (WebRTC) players

Your Server Setup

• Matchbox Signaling: ws://ruinborn.thefirstboss.com:3536
• STUN Server: stun:ruinborn.thefirstboss.com:3578

How Players Find Each Other

WebRTC/Browser Mode (Room-Based)

1. Host creates a game:

   • Clicks "Host Game"
   • Game generates a 6-character Room Code (e.g., "ABC123")
   • Share this code with friends

2. Players join:

   • Enter the Room Code in the "Join Game" field
   • Click "Join"
   • Matchbox connects all players in the same room

Example Flow

Host (Browser):
- Clicks "Host"
- Gets Room Code: "XYZ789"
- Tells friend: "Join room XYZ789"

Player (Browser):
- Types "XYZ789" in join field
- Clicks "Join"
- Connected!

Testing Scenarios

Scenario 1: Browser to Browser (WebRTC)

✅ Works!

1. Open game in Chrome: host.com/game
2. Host creates game → Gets code "ABC123"
3. Open game in Firefox: host.com/game
4. Join with code "ABC123"
5. Both connected via WebRTC!

Scenario 2: PC to Browser (Mixed)

❌ Doesn't Work!

PC (ENet) ←→ Browser (WebRTC) = INCOMPATIBLE

Scenario 3: Phone Browser to PC Browser (WebRTC)

✅ Works!

1. PC Browser hosts → code "XYZ456"
2. Phone browser joins "XYZ456"
3. Connected via WebRTC!

Scenario 4: PC to PC (ENet)

✅ Works!

1. PC1 hosts → Shows IP: 192.168.1.100
2. PC2 joins → Enters "192.168.1.100"
3. Connected via ENet!

Can PC Host and Browser Join?

Short Answer: No, not with the current setup.

Long Answer: ENet (PC) and WebRTC (Browser) use completely different protocols. They can't talk to each other directly.

Solution: If you want cross-platform play, you have two options:

Option A: Make PC Use WebRTC Too

Update PC builds to also use WebRTC when you want to play with browser users:

# Force WebRTC mode even on native builds
use_webrtc = true  # in network_manager.gd

Then PC and Browser can use the same room codes!

Option B: Use a Dedicated Server

Run a dedicated server that:

• Accepts both ENet and WebRTC connections
• Bridges between them

This is more complex but allows true cross-platform play.

Room Codes

Room codes are automatically generated as 6-character codes:

• Easy to share (just text it!)
• No IP addresses to remember
• Works through NATs/firewalls

Example codes: ABC123, XYZ789, PLAYER, GAME42

Exporting for Web

1. Export HTML5:

   • Project → Export → Add → HTML5 (WebAssembly)
   • Export the project

2. Host on Web Server:

   # Your files
   python -m http.server 8000
   

3. Players Access:

   • http://yoursite.com/game
   • Works on PC browsers, phone browsers, tablets!

Security Notes

• Room codes are NOT secure (anyone with code can join)
• For production, add:
  • Password-protected rooms
  • Room capacity limits
  • Ban/kick functionality
  • Room expiration

Troubleshooting

"Connection failed" in browser:

• Check matchbox server is running: netstat -tulpn | grep 3536
• Check firewall allows port 3536
• Check browser console for errors

"Can't see other players":

• Make sure both players entered the SAME room code
• Check both are using browser builds (not mixing PC/browser)

"Stuck on connecting":

• STUN server must be reachable
• Check port 3578 is open
• Try different browsers

Current Limitations

1. PC (ENet) ←/→ Browser (WebRTC) can't play together
2. Need to share room codes manually (no lobby browser yet)
3. No reconnection if disconnected (must rejoin)

Next Steps

To improve multiplayer:

1. Add lobby browser (see active rooms)
2. Add friend codes/invites
3. Add voice chat (WebRTC supports it!)
4. Add dedicated server for PC↔Browser bridge