EditorPlayModeSync

Synchronizes Play Mode enter/exit across multiple Unity Editor instances on the local network. Uses UDP broadcast on port 8052 to propagate state changes, enabling multi-instance testing workflows.

Definition

Namespace: Paragon.Core.Editor Assembly: Paragon.Editor.dll

[InitializeOnLoad]
public class EditorPlayModeSync : IDisposable

Attributes: [InitializeOnLoad] — initializes via static constructor on editor load. Implements: IDisposable

Remarks

This utility is designed for multi-editor workflows where you need multiple Unity instances to enter or exit Play Mode simultaneously (e.g., testing networked multiplayer locally).

Initialization Flow

1. Static constructor runs on editor load ([InitializeOnLoad])

2. Resolves the project name via ParagonPaths.Project for self-identification

3. Subscribes to EditorApplication.playModeStateChanged to broadcast state changes

4. Subscribes to EditorApplication.update to process received messages

5. Creates a UDP client bound to port 8052 with broadcast enabled

Message Protocol

Messages are plain ASCII strings in the format: {clientName}:{PlayModeStateChange}

Message	Meaning
ProjectA:EnteredPlayMode	Project A entered Play Mode
ProjectA:ExitingPlayMode	Project A is exiting Play Mode

Self-Filtering

Each editor identifies itself by its project name (ParagonPaths.Project). When a message is received with a matching client name, it is ignored to prevent feedback loops.

Delayed Execution

Play mode transitions triggered by remote messages are delayed by 1 second via Yield.WaitForEditorSeconds to ensure stable state before transitioning.

Quick Lookup

Goal	How
Enable enter-play sync	Set EditorPlayModeSync.SyncEnterPlay = true in Editor Preferences
Enable exit-play sync	Set EditorPlayModeSync.SyncExitPlay = true in Editor Preferences
Disable all syncing	Set both SyncEnterPlay and SyncExitPlay to false
UDP port	8052 (hardcoded)
Message format	{clientName}:{PlayModeStateChange}

Properties

Property	Type	Access	Description
SyncEnterPlay	bool	public static	When true, entering Play Mode in another editor triggers enter here. Persisted via [EditorPreference].
SyncExitPlay	bool	public static	When true, exiting Play Mode in another editor triggers exit here. Persisted via [EditorPreference].

Fields

Field	Type	Access	Description
port	int	private const	UDP broadcast port (8052)
udpClient	UdpClient	private static	The UDP client for sending and receiving broadcasts
clientName	string	private static readonly	This editor's project name for self-identification
syncedPlayMode	PlayModeStateChange?	private static	Queued play mode change received from another editor

Methods

Connect (private static)

Creates and binds the UdpClient to port 8052 with ReuseAddress and EnableBroadcast, then begins async receive.

Broadcast (private static)

private static void Broadcast(string payload)

Sends a UDP broadcast message. No-ops if both sync preferences are disabled.

ReceiveCallback (private static)

Async callback for UdpClient.BeginReceive. Decodes the message and passes to OnMessageReceived, then re-registers for the next receive.

OnMessageReceived (private static)

Parses the {clientName}:{state} message. Ignores messages from self. Sets syncedPlayMode for processing in the next Update.

Update (private static)

Called every editor frame via EditorApplication.update. If syncedPlayMode is set:

• ExitingPlayMode + SyncExitPlay enabled + currently playing → exit play mode after 1s

• EnteredPlayMode + SyncEnterPlay enabled + not playing → enter play mode after 1s

Disconnect (private static)

Closes and nullifies the UDP client.

IDisposable.Dispose (explicit)

Calls Disconnect() to clean up the UDP client.

Common Pitfalls

Port conflict Port 8052 is hardcoded. If another application uses this port, the UdpClient.Bind will throw a SocketException. There is no fallback port mechanism.

Firewall blocking UDP broadcast may be blocked by firewall rules. Ensure port 8052 UDP is allowed for local network broadcast.

No encryption or authentication Messages are plain ASCII over UDP broadcast. Any application on the local network can send messages on port 8052 that will be interpreted as play mode commands.

Feedback loop prevention relies on project name If two editors share the same ParagonPaths.Project value, they will filter out each other's messages as "self" and syncing will not work.

See Also

• EditorPlayModeSync Overview — subsystem overview

• Yield — async delay via WaitForEditorSeconds