# Local Testing Setup Guide

## Testing Both Players in Same Scene

When testing the UDP avatar sync system with both broadcaster and receiver in the same Unity scene, you need to handle port conflicts properly.

### The Port Conflict Issue

The error you encountered:
```
Failed to start UDP listener: Only one usage of each socket address (protocol/network address/port) is normally permitted.
```

This happens because both components try to bind to the same UDP port (8080) simultaneously.

## Solution: Updated Receiver with Port Sharing

The `UDPAvatarReceiver` has been updated with port sharing capabilities:

### New Settings in Inspector

- **Allow Port Sharing**: ✅ Enable this for local testing
- **Listen Port**: 8080 (or will auto-find alternative)

### How It Works

1. **Port Sharing Enabled**: Uses `SO_REUSEADDR` socket option to allow multiple bindings
2. **Fallback Ports**: If port sharing fails, tries ports 8081, 8082, 8083, etc.
3. **Debug Info**: Shows actual port being used in the GUI

## Local Testing Setup

### GameObject 1: Player 1 (Broadcaster + Receiver)
```
Avatar Player 1
├── UDPAvatarBroadcaster
│   ├── Player ID: 1
│   ├── Avatar Root: [Player 1 Avatar]
│   └── Show Debug Info: ✅
└── UDPAvatarReceiver  
    ├── Target Player ID: 2 (receive from Player 2)
    ├── Target Avatar Root: [Player 2 Avatar Clone]
    ├── Allow Port Sharing: ✅
    └── Show Debug Info: ✅
```

### GameObject 2: Player 2 (Broadcaster + Receiver)
```
Avatar Player 2
├── UDPAvatarBroadcaster
│   ├── Player ID: 2
│   ├── Avatar Root: [Player 2 Avatar]
│   └── Show Debug Info: ✅
└── UDPAvatarReceiver
    ├── Target Player ID: 1 (receive from Player 1)
    ├── Target Avatar Root: [Player 1 Avatar Clone]
    ├── Allow Port Sharing: ✅
    └── Show Debug Info: ✅
```

## Alternative Setup Methods

### Method 1: Different Ports (Simple)
- Player 1 Broadcaster: Port 8080
- Player 2 Broadcaster: Port 8081
- Update receivers to listen on corresponding ports

### Method 2: Single Broadcaster (Minimal)
- One broadcaster component sending data
- Multiple receivers in scene listening
- Good for testing receiver logic only

### Method 3: Separate Scenes (Real-world)
- Build and run multiple instances of your game
- Most accurate representation of real multiplayer

## Troubleshooting

### Still Getting Port Errors?

1. **Check Windows Firewall**:
   ```
   Allow Unity.exe through Windows Defender Firewall
   Allow UDP port 8080-8085
   ```

2. **Verify Port Sharing Setting**:
   ```
   UDPAvatarReceiver → Allow Port Sharing: ✅
   ```

3. **Check Console for Alternative Ports**:
   ```
   Look for: "UDP listener started on alternative port 8081"
   ```

### No Data Being Received?

1. **Verify Player IDs**:
   - Broadcaster Player ID: 1
   - Receiver Target Player ID: 1 (to receive from broadcaster)

2. **Check Debug GUI**:
   - Broadcaster: "Broadcasting" status
   - Receiver: "Listen Port" shows actual port

3. **Test Loopback**:
   - Set Receiver Target Player ID: 0 (receive from any)
   - Should receive own broadcasts

## Debug Information

Enable debug info on both components to see:

**Broadcaster GUI (Top-left)**:
- Player ID and broadcast status
- Sequence number (should increment)
- Update rate and packet size

**Receiver GUI (Top-right)**:
- Listen port (actual port being used)
- Packets received/dropped
- Target player ID

## Production vs Testing

| Environment | Setup | Port Handling |
|-------------|-------|---------------|
| **Local Testing** | Same scene, port sharing | Allow Port Sharing: ✅ |
| **LAN/Hotspot** | Separate devices | Standard UDP binding |
| **Production** | Different machines | No port conflicts |

## Quick Checklist

1. ✅ Enable "Allow Port Sharing" on all receivers
2. ✅ Set unique Player IDs (1, 2, 3...)
3. ✅ Set correct Target Player IDs on receivers
4. ✅ Enable debug info to monitor status
5. ✅ Check console for port conflict messages
6. ✅ Verify Windows Firewall allows Unity/UDP

The updated receiver should now handle local testing scenarios gracefully!