Error sending the message: NetworkId is invalid, likely caused by stale connection 0.

Unity Engine
,
1

Hi, in my multiplayer game a player can have de character that shoot projectil. To do that I originaly Spawn the projectil when needed but it resulte a delay for the player befor the projectil is visible.

To improve that I tried to make an objectPooling système.
There is the code :

using System.Collections.Generic;
using Unity.Netcode;
using UnityEngine;

public class NetWorkObjectPooling : NetworkBehaviour
{
    public static NetWorkObjectPooling Instance;
    private Dictionary<string, Queue<NetworkObject>> poolDictionary;

    private void Awake()
    {
        if (Instance != null)
        {
            Debug.Log("Found more than one NetworkObjectPooling, new is destroyed");
            Destroy(this.gameObject);
            return;
        }
        Instance = this;
        poolDictionary = new Dictionary<string, Queue<NetworkObject>>();
        DontDestroyOnLoad(this.gameObject);
    }

    public void CreatePool(string tag, GameObject prefab, int size)
    {
        if (!IsServer) return;
        Queue<NetworkObject> objectPool = new Queue<NetworkObject>();
        List<ulong> objectIDs = new List<ulong>();

        for (int i = 0; i < size; i++)
        {
            var obj = Instantiate(prefab);
            obj.gameObject.SetActive(false);
            NetworkObject objNetwork = obj.GetComponent<NetworkObject>();
            if (objNetwork != null)
            {
                objNetwork.Spawn();
                objectPool.Enqueue(objNetwork);
                objectIDs.Add(objNetwork.NetworkObjectId);
            }
            else
            {
                Destroy(obj);
            }
        }

        poolDictionary.Add(tag, objectPool);
        AddToPoolClientRpc(tag, objectIDs.ToArray());
    }

    [ClientRpc]
    public void AddToPoolClientRpc(string tag, ulong[] objectIDs)
    {
        if (IsServer) return;

        Queue<NetworkObject> objectPool = new Queue<NetworkObject>();
        foreach (ulong id in objectIDs)
        {
            NetworkObject networkObject = NetworkManager.Singleton.SpawnManager.SpawnedObjects[id];
            if (networkObject != null)
            {
                networkObject.gameObject.SetActive(false);
                objectPool.Enqueue(networkObject);
            }
        }
        poolDictionary.Add(tag, objectPool);
    }

    public NetworkObject GetFromPool(string tag, Vector3 position, Quaternion rotation)
    {
        if (!poolDictionary.ContainsKey(tag))
        {
            Debug.LogWarning("Pool with tag " + tag + " doesn't exist.");
            return null;
        }

        NetworkObject objectToSpawn = poolDictionary[tag].Dequeue();
        DequeueServerRpc(tag, NetworkManager.Singleton.LocalClientId);
        objectToSpawn.transform.position = position;
        objectToSpawn.transform.rotation = rotation;
        objectToSpawn.gameObject.SetActive(true);
        objectToSpawn.transform.parent = null; // Unparent the object if it has a parent

        return objectToSpawn;
    }

    [ServerRpc(RequireOwnership = false)]
    private void DequeueServerRpc(string tag, ulong clientId)
    {
        DequeueClientRpc(tag, clientId);
    }

    [ClientRpc]
    private void DequeueClientRpc(string tag, ulong clientId)
    {
        if (NetworkManager.Singleton.LocalClientId == clientId) return;
        poolDictionary[tag].Dequeue();
    }

    public void ReturnToPool(string tag, GameObject objectToReturn)
    {
        if (!poolDictionary.ContainsKey(tag))
        {
            Debug.LogWarning("Pool with tag " + tag + " doesn't exist.");
            Destroy(objectToReturn.gameObject); // Si le pool n'existe pas, détruisez l'objet
            return;
        }

        objectToReturn.gameObject.SetActive(false);
        NetworkObject networkObj = objectToReturn.GetComponent<NetworkObject>();
        if (networkObj != null)
        {
            poolDictionary[tag].Enqueue(networkObj);
            EnqueueServerRpc(tag, NetworkManager.Singleton.LocalClientId, networkObj.NetworkObjectId);
        }
        else
        {
            Debug.LogWarning("Object is not on the network, we destroy it");
            Destroy(objectToReturn.gameObject); // détruisez l'objet
        }
    }

    [ServerRpc(RequireOwnership = false)]
    private void EnqueueServerRpc(string tag, ulong clientId, ulong objectId)
    {
        EnqueueClientRpc(tag, clientId, objectId);
    }

    [ClientRpc]
    private void EnqueueClientRpc(string tag, ulong clientId, ulong objectId)
    {
        if (NetworkManager.Singleton.LocalClientId == clientId) return;

        NetworkObject networkObject = NetworkManager.Singleton.SpawnManager.SpawnedObjects[objectId];
        if (networkObject != null)
        {
            poolDictionary[tag].Enqueue(networkObject);
        }
    }
}

I supposed something is not do well because know if I want to sent RPC to an pooled object I got this message error :

Error sending the message: NetworkId is invalid, likely caused by stale connection 0.
UnityEngine.Debug:LogError (object)
Unity.Netcode.Transports.UTP.UnityTransport:SendBatchedMessages (Unity.Netcode.Transports.UTP.UnityTransport/SendTarget,Unity.Netcode.Transports.UTP.BatchedSendQueue) (at Library/PackageCache/com.unity.netcode.gameobjects@1.0.2/Runtime/Transports/UTP/UnityTransport.cs:681)
Unity.Netcode.Transports.UTP.UnityTransport:Update () (at Library/PackageCache/com.unity.netcode.gameobjects@1.0.2/Runtime/Transports/UTP/UnityTransport.cs:829)

For exemple with the missileScript :

using System;
using System.Collections;
using System.Collections.Generic;
using Unity.Collections;
using Unity.Netcode;
using UnityEngine;
using static PlayerMovement;
using static Unity.VisualScripting.Member;

public class Missile :  NetworkBehaviour
{
    [SerializeField] float speed;

    public Vector3 dir;
    public int damageOnHit;
    [SerializeField] Rigidbody rb;
    private Health ownerHealth;
    [SerializeField] GameObject visualPart;
    [SerializeField] GameObject hitGameObject;

    [SerializeField] float timeBeforDespawn = 0f;
    [SerializeField] bool despawnTrigger = false;
    [SerializeField] bool hitTrigger = false;
    float currentTimer = 0f;
    private bool firstframe = true;
    private bool init = false;

    FixedString64Bytes localIdentificatorID;
    private void Start()
    {
        Debug.Log("Missile spawn");
        Debug.Log("dir :" + dir.ToString());
    }
    public void InitLocalyForTestOnly(Vector3 pos, Vector3 direction, int damageonHit, FixedString64Bytes identificatorID)
    {
        localIdentificatorID = identificatorID;
        this.transform.position = pos;
        init = true;
        dir = direction;
        this.damageOnHit = damageonHit;
        if (IdentificatorManager.instance != null)
        {
            GameObject obj = IdentificatorManager.instance.GetFromID(identificatorID.ToString());
            if (obj != null)
            {
                ownerHealth = obj.GetComponent<Health>();
                if (ownerHealth == null)
                {
                    ownerHealth = obj.GetComponentInChildren<Health>();
                }
            }
        }

    }

    public void Init(Vector3 pos, Vector3 direction, int damageonHit, FixedString64Bytes identificatorID)
    {
        if(NetworkManager.IsServer)
        {
            TestClientRpc();
            InitClientRpc(pos, direction, damageonHit, identificatorID);
        }
        else
        {
            InitServerRpc(pos, direction, damageonHit, identificatorID);
        }
    }
    [ServerRpc]
    public void InitServerRpc(Vector3 pos, Vector3 direction, int damageonHit, FixedString64Bytes identificatorID)
    {
        InitClientRpc(pos, direction, damageonHit, identificatorID);
    }

    [ClientRpc]
    public void TestClientRpc()
    {
        Debug.Log("Thats working");
    }
    [ClientRpc]
    public void InitClientRpc(Vector3 pos, Vector3 direction, int damageonHit, FixedString64Bytes identificatorID)
    {
        this.transform.position = pos;
        init = true;
        dir = direction;
        this.damageOnHit = damageonHit;
        if(IdentificatorManager.instance != null)
        {
            GameObject obj = IdentificatorManager.instance.GetFromID(identificatorID.ToString());
            if (obj != null)
            {
                ownerHealth = obj.GetComponent<Health>();
                if (ownerHealth == null)
                {
                    ownerHealth = obj.GetComponentInChildren<Health>();
                }
            }
        }
       
    }


    // Update is called once per frame
    void Update()
    {
        Debug.Log("POS" + this.transform.position.ToString());
        if (!init)
        {  
            return;
        }
        if(firstframe && init)
        {
            firstframe = false;
            visualPart.SetActive(true);
        }

        if (despawnTrigger) return;
        if(hitTrigger)
        {
            rb.velocity = new Vector2(0, 0);
            currentTimer += Time.deltaTime;
            if(currentTimer > timeBeforDespawn)
            {
                SyncActiveState syncScript = GetComponentInParent<SyncActiveState>();
                this.gameObject.SetActive(false);
                syncScript.SetActiveState(false);
                if (IsServer && gameObject.GetComponent<NetworkObject>().IsSpawned)
                {
                    Debug.Log("Despawn : " + this.gameObject.name);
                   
                    gameObject.GetComponent<NetworkObject>().Despawn();
                    despawnTrigger = true;
                }
            }
            return;
        }
        rb.velocity = dir*speed;
       
    }
    [ClientRpc]
    public void STOPClientRpc()
    {
        SyncActiveState syncScript = GetComponentInParent<SyncActiveState>();
        if (syncScript != null)
        {
            hitTrigger = true;
            currentTimer = 0f;
            visualPart.SetActive(false);

            if (hitGameObject != null) hitGameObject.SetActive(true);
            //this.gameObject.SetActive(false);
            //
            //if (IsServer && gameObject.GetComponent<NetworkObject>().IsSpawned)
            //{
            //    Debug.Log("Despawn : " + this.gameObject.name);
            //   
            //    gameObject.GetComponent<NetworkObject>().Despawn();
            //
            //}
        }
    }

    void OnDrawGizmos()
    {
        Gizmos.color = Color.red;
        Gizmos.DrawWireSphere(this.transform.position, 1.3f);
    }

    public void STOP(Collider collision)
    {
        SyncActiveState syncScript = GetComponentInParent<SyncActiveState>();
        if (syncScript != null)
        {
            hitTrigger = true;
            currentTimer = 0f;
            visualPart.SetActive(false);

            if (hitGameObject != null)
            {
                // Récupérer le point de collision et faire un raycast pour obtenir la normale
                Vector3 hitPosition = collision.ClosestPoint(transform.position);
                Vector3 hitNormal = Vector3.up; // Valeur par défaut si le raycast échoue

                RaycastHit hitInfo;
                if (Physics.Raycast(transform.position, (hitPosition - transform.position).normalized, out hitInfo))
                {
                    hitNormal = hitInfo.normal;
                }

                hitGameObject.SetActive(true);
                hitGameObject.transform.position = hitPosition;
                hitGameObject.transform.rotation = Quaternion.LookRotation(hitNormal);
            }



            if (IsServer)
            {
                STOPClientRpc();

                // Remplacer Physics2D.OverlapCircleAll par Physics.OverlapSphere pour la détection 3D
                Collider[] hitColliders = Physics.OverlapSphere(this.transform.position, 1.3f);

                foreach (Collider hitCollider in hitColliders)
                {
                    Health otherHealth = hitCollider.gameObject.GetComponent<Health>();
                    if (otherHealth != null)
                    {
                        if (ownerHealth != null && ownerHealth.gameObject.CompareTag("Player") && otherHealth.gameObject.CompareTag("Player") && MultiplayerManager.instance != null && MultiplayerManager.instance.GetDifficulty() == 0) continue;
                        else if (ownerHealth != null) otherHealth.Damage(damageOnHit, ownerHealth.transform);
                        else otherHealth.Damage(damageOnHit, this.transform);
                    }
                }

                if (IsServer && NetWorkObjectPooling.Instance != null)
                {
                    NetWorkObjectPooling.Instance.ReturnToPool("Projectile",this.gameObject);
                }
            }
            // Désactiver l'objet si nécessaire (commenté)
            // this.gameObject.SetActive(false);

            // Désancrer l'objet réseau si nécessaire (commenté)
            // if (IsServer && gameObject.GetComponent<NetworkObject>().IsSpawned)
            // {
            //     Debug.Log("Despawn : " + this.gameObject.name);
            //     gameObject.GetComponent<NetworkObject>().Despawn();
            // }
        }
    }

    void OnTriggerEnter(UnityEngine.Collider collision)
    {
        if (hitTrigger) return;

        // Récupérer le composant Health sur l'objet collisionné ou ses enfants
        Health otherHealth = collision.gameObject.GetComponent<Health>();
        if (otherHealth == null)
        {
            otherHealth = collision.gameObject.GetComponentInChildren<Health>();
        }

        // Vérifier si le composant Health trouvé est celui du propriétaire
        if (otherHealth != null && ownerHealth != null && otherHealth.gameObject == ownerHealth.gameObject)
        {
            return;
        }

        // Si un composant Health valide est trouvé, effectuer une action
        if (otherHealth != null)
        {
            // Remplacez STOP() par l'action désirée, comme infliger des dégâts
            // if (IsHost) otherHealth.Damage(damageOnHit, this.transform);
            STOP(collision);
        }

        // Si l'objet collisionné a certains tags spécifiques, effectuer une action
        if (collision.gameObject.tag == "Border" || collision.gameObject.tag == "Deco" || collision.gameObject.tag == "Wall")
        {
            STOP(collision);
        }
    }

    public override void OnNetworkDespawn()
    {
        // Logique de nettoyage ou préparation avant destruction
        base.OnNetworkDespawn(); // Appel à la base si nécessaire
        Debug.Log("Destroy" + this.gameObject.name);
        Destroy(gameObject);
    }
}

If i call the InitLocalyForTestOnly I have no problem and the missile do well localy, but if I call the Init which sendRPC, I have the error.
TestClientRpc(); produce an error as well.

The polled objects are visible In the scene but it’s seems not initialize correctly, for exemple I added those debug :

Debug.Log("local isServer :" +IsServer.ToString());
Debug.Log("local isClient :" +IsClient.ToString());
Debug.Log("local isOwner  :" +IsOwner.ToString());
Debug.Log("local isHost   :" + IsHost.ToString());


local isServer :False
UnityEngine.Debug:Log (object)
Missile:Init (UnityEngine.Vector3,UnityEngine.Vector3,int,Unity.Collections.FixedString64Bytes) (at Assets/Missile.cs:58)
AttackScript:AttackPrefab (UnityEngine.Vector3,PlayerData/WeaponType) (at Assets/AttackScript.cs:441)
PlayerAction:Attack () (at Assets/PlayerAction.cs:84)
PlayerAction:<Start>b__14_0 () (at Assets/PlayerAction.cs:58)
UnityEngine.Events.UnityEvent:Invoke ()
RPGCharacterAnims.RPGCharacterAnimatorEvents:Hit () (at Assets/ExplosiveLLC/RPG Character Mecanim Animation Pack/Code/RPGCharacterAnimatorEvents.cs:33)

local isClient :False
UnityEngine.Debug:Log (object)
Missile:Init (UnityEngine.Vector3,UnityEngine.Vector3,int,Unity.Collections.FixedString64Bytes) (at Assets/Missile.cs:59)
AttackScript:AttackPrefab (UnityEngine.Vector3,PlayerData/WeaponType) (at Assets/AttackScript.cs:441)
PlayerAction:Attack () (at Assets/PlayerAction.cs:84)
PlayerAction:<Start>b__14_0 () (at Assets/PlayerAction.cs:58)
UnityEngine.Events.UnityEvent:Invoke ()
RPGCharacterAnims.RPGCharacterAnimatorEvents:Hit () (at Assets/ExplosiveLLC/RPG Character Mecanim Animation Pack/Code/RPGCharacterAnimatorEvents.cs:33)

local isOwner  :False
UnityEngine.Debug:Log (object)
Missile:Init (UnityEngine.Vector3,UnityEngine.Vector3,int,Unity.Collections.FixedString64Bytes) (at Assets/Missile.cs:60)
AttackScript:AttackPrefab (UnityEngine.Vector3,PlayerData/WeaponType) (at Assets/AttackScript.cs:441)
PlayerAction:Attack () (at Assets/PlayerAction.cs:84)
PlayerAction:<Start>b__14_0 () (at Assets/PlayerAction.cs:58)
UnityEngine.Events.UnityEvent:Invoke ()
RPGCharacterAnims.RPGCharacterAnimatorEvents:Hit () (at Assets/ExplosiveLLC/RPG Character Mecanim Animation Pack/Code/RPGCharacterAnimatorEvents.cs:33)

local isHost   :False
UnityEngine.Debug:Log (object)
Missile:Init (UnityEngine.Vector3,UnityEngine.Vector3,int,Unity.Collections.FixedString64Bytes) (at Assets/Missile.cs:61)
AttackScript:AttackPrefab (UnityEngine.Vector3,PlayerData/WeaponType) (at Assets/AttackScript.cs:441)
PlayerAction:Attack () (at Assets/PlayerAction.cs:84)
PlayerAction:<Start>b__14_0 () (at Assets/PlayerAction.cs:58)
UnityEngine.Events.UnityEvent:Invoke ()
RPGCharacterAnims.RPGCharacterAnimatorEvents:Hit () (at Assets/ExplosiveLLC/RPG Character Mecanim Animation Pack/Code/RPGCharacterAnimatorEvents.cs:33)

When Is call to get an object from the pool, the objets are spawned :

9861744--1420809--upload_2024-5-29_17-45-25.png
9861744--1420809--upload_2024-5-29_17-45-25.png1217×474 85.2 KB

I don’t know what is appening…

Thanks for your help

2

Pooling doesn’t fix the latency issue. Also NGO has network object pooling class built in.

To fix the latency issue, when the client fires a projectile, a local non-networked version of that projectile is spawned. It does not interact with anything, it’s purely visual. If the server determines a hit, it sends an RPC and the client destroys its local projectile.

So much for the premise but the latency will merely be moved towards the impact. That however is already a worthwhile improvement for the feel of the game.

Unity’s Boss Room example game utilizes this client-side prediction of object spawning and animations.

3

Hi,
Thanks for your response. just for information, the problem was Settinf the GameObject.SetActive(false) when creating a pool.

Does that mean that I don’t even need to spawn projectil on network?
I can use local projectil, without interraction on clients and one with interaction on the server that can hit and damage?

Thanks for your help.

4

Sure, you could have the interacting projectile on the server only as long as it sends the “destroyed” RPC and clients know which of their local projectiles they should destroy.