SingletonNetworkBehaviour

Abstract generic singleton base class for network behaviours that need exactly one authoritative instance in the networked scene. Combines the SingletonBehaviour pattern (find → load → create) with automatic NetworkObject.Spawn() on Start().

Definition

Namespace: Paragon.Core.Network Assembly: Paragon.dll

[SingletonSettings]
public abstract class SingletonNetworkBehaviour<T> : ParagonNetworkBehaviour
    where T : SingletonNetworkBehaviour<T>

Inheritance: NetworkBehaviour → ParagonNetworkBehaviour → SingletonNetworkBehaviour<T>

Remarks

This class mirrors the SingletonBehaviour<T> pattern used by non-networked singletons but adds network-specific behaviour:

1. Instance resolution follows a chain: cached instance → FindFirstObjectByType<T>() → Resources.Load<T>(assetPath) → create new GameObject with component.

2. Auto-spawn: On Start(), if the NetworkObject is not already spawned, it calls NetworkObject.Spawn() automatically. This ensures the singleton is network-visible as soon as it enters the scene.

3. DontDestroyOnLoad support via [SingletonSettings(DontDestroyOnLoad = true)].

4. Editor asset creation: In the editor, if an AssetPath is configured and no prefab exists, one is automatically created in Assets/Resources/.

The class uses the curiously recurring template pattern (CRTP) — T must be the concrete subclass itself.

Play Mode only: Instance asserts that Application.isPlaying is true. Accessing the singleton outside Play Mode will trigger a Debug.Assert.

Quick Lookup

Goal	How
Access the singleton	MySingleton.Instance
Check debug state	MySingleton.DebugEnabled
Create a network singleton	Subclass with [SingletonSettings] (see example)

Properties

Instance (static)

Returns the singleton instance, creating or finding it if necessary.

public static T Instance { get; }

Resolution order:

1. Cached instance field

2. FindFirstObjectByType<T>() in the scene

3. Resources.Load<T>(assetPath) if AssetPath is configured

4. Create new GameObject with AddComponent<T>()

DebugEnabled (static, new)

Whether debug output is enabled for the singleton instance. Shadows the instance-level property for convenient static access.

public new static bool DebugEnabled { get; }

Extension Points

Optional Overrides

Method	Purpose
Awake()	Initializes the singleton. Sets instance, applies DontDestroyOnLoad and hide flags. Call base.Awake() if overriding.
Start()	Auto-spawns the NetworkObject if not already spawned. Call base.Start() if overriding.
OnDestroy()	Clears the static instance reference. Call base.OnDestroy() if overriding.

Implementation Requirements

When subclassing SingletonNetworkBehaviour<T>, you MUST:

1. Pass the concrete class as T (CRTP): class MyManager : SingletonNetworkBehaviour<MyManager>

2. Apply [SingletonSettings] attribute (even with defaults)

3. Ensure the prefab has a NetworkObject component (required for Spawn() in Start())

You SHOULD:

• Set AssetPath in [SingletonSettings] if the singleton should be loadable from Resources

• Set DontDestroyOnLoad = true for managers that persist across scenes

• Call base.Awake() and base.Start() if overriding lifecycle methods

You SHOULD NOT:

• Access Instance outside of Play Mode (assertion will fire)

• Create multiple instances of the same singleton type (assertion will fire in Awake())

Common Pitfalls

Missing NetworkObject component Start() calls NetworkObject.Spawn(). If the GameObject lacks a NetworkObject, this will throw a NullReferenceException. Always ensure the prefab or dynamically created object has a NetworkObject.

Duplicate singleton instances Creating two instances of the same type triggers a Debug.Assert in Awake(). Ensure only one instance exists — the resolution chain (find → load → create) handles this automatically when using Instance.

Overriding Awake/Start without calling base Forgetting base.Awake() skips singleton registration, DontDestroyOnLoad, and hide flag setup. Forgetting base.Start() skips auto-spawning on the network.

Examples

Creating a Network Singleton Manager

using Paragon.Core.Network;

[SingletonSettings(DontDestroyOnLoad = true, AssetPath = "Game Session Manager")]
public class GameSessionManager : SingletonNetworkBehaviour<GameSessionManager>
{
    protected override void Awake()
    {
        base.Awake();
        // Custom initialization
    }

    protected override void Start()
    {
        base.Start(); // Auto-spawns NetworkObject
        // Custom start logic
    }
}

Accessing the Singleton

// From anywhere in game code
GameSessionManager.Instance.DoSomething();

// Check debug state
if (GameSessionManager.DebugEnabled)
{
    Debug.Log("Session manager debug info...");
}

See Also

• ParagonNetworkBehaviour — the base class this extends

• NetworkManager — the network system entry point