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[Multiplayer] Differentiate Main vs Cloned Editor Instances

Solution

editor scriptingplay modeworkflow

Unity 2022.3.x - Unity 6.3.x

Published 30 days ago

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Reviewed by _architect

Chief Editor

80 posts
Issue

 Identifying the primary Unity Editor instance versus virtual project clones is difficult when initialization logic must only occur once. In multiplayer testing scenarios, secondary instances may trigger redundant CurrentPlayer.IsMainEditor checks, attempt to access shared database resources, or load assets simultaneously, causing file access conflicts and performance degradation within the Unity.Multiplayer.Playmode environment.

Quick-Fix

To detect the primary editor instance, query the CurrentPlayer.IsMainEditor boolean property located within the Unity.Multiplayer.Playmode namespace.

Expand Analysis

Branching logic based on the editor role is accomplished by evaluating the CurrentPlayer.IsMainEditor flag. This property determines if the execution occurs in the host process or a temporary clone generated for multiplayer testing.

To implement this check:

  • Import the Unity.Multiplayer.Playmode namespace at the top of your startup manager.
  • Use the InitializeOnLoadMethod attribute to ensure the check runs immediately upon project opening.
  • Wrap instance-specific logic in a conditional block that queries CurrentPlayer.IsMainEditor.

Additional Tips

  • Virtual clones share the same ProjectSettings but have unique temporary folders; avoid writing persistent data to local paths from a secondary instance to prevent overwriting main project data.
  • If your startup manager logic involves networking or disk I/O, using CurrentPlayer.IsMainEditor is critical to avoid race conditions between simultaneous editor processes.

Copy 



using Unity.Multiplayer.Playmode;
using UnityEditor;
using UnityEngine;

public static class yourStartupManager
{
    [InitializeOnLoadMethod]
    private static void OnEditorLoad()
    {
        if (CurrentPlayer.IsMainEditor)
        {
            // Execute startup sequence or main instance-specific logic
            Debug.Log("This is the main editor instance.");
        }
        else
        {
            // Execute logic for virtual/cloned instances, if any
            Debug.Log("This is a virtual/cloned editor instance.");
        }
    }
}

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Content inspired by a Unity discussion post.