Question NetworkVariable in Netcode for game objects not working

Hi , I am new to Netcode for game objects.

Recently, I tested NetworkVariable functionality in both MLAPI 0.1.0 and Netcode 1.0.0. In my project, I tried to create a scene "Start Point" for handling server connection. Then, I created a Lobby scene to manage the names of connected players.

In StartPoint Scene, input field will be provided to enter text. In Lobby scene, the TextUI will be update when NetworkVariable is changed, and clients who are joining server will modify NetworkVariable<FixedString64Bytes> by their text in StartPoint scene .

The problem is, when using Netcode 1.0.0, as mentioned in title, NetworkVariables from clients/ host does not sync together. My current solution is, I need to call ServerRpc--> ClientRpc to manage variable changes.

Here is my setting from inspector:

Here is my code:

Code (CSharp):

1. using UnityEngine;
2. using Unity.Netcode;
3. using UnityEngine.SceneManagement;
4. using Unity.Collections;
5. using TMPro;
6.  
7. public class StartPoint : NetworkBehaviour
8. {
9.     public TMP_InputField YourName_Field;
10.  
11.     [SerializeField]
12.     public static string YourName;
13.  
14.     // a variable belongs to one client and can be read by all clients
15.     public static NetworkVariable<FixedString64Bytes> PlayerName = new NetworkVariable<FixedString64Bytes>();    
16.  
17.     public static StartPoint singleton = null;
18.  
19.     public GameObject SetActivePanel;
20.  
21.     public void Awake()
22.     {
23.         DontDestroyOnLoad(this.gameObject);
24.         if(singleton == null)
25.         {
26.             singleton = this;
27.         }
28.         else if (singleton != this)
29.         {
30.             Debug.Log("destroy");
31.             Destroy(this);
32.         }
33.  
34.     }
35.  
36.     public void StartHost()
37.     {
38.         NetworkManager.Singleton.StartHost();
39.         InitPlayerName();
40.         NetworkManager.Singleton.SceneManager.SetClientSynchronizationMode(LoadSceneMode.Single);
41.         Debug.Log("starthost");
42.         SetActivePanel.SetActive(false);
43.         NetworkManager.Singleton.SceneManager.LoadScene("Lobby" , LoadSceneMode.Single);
44.     }
45.  
46.  
47.     public void StartClient()
48.     {
49.         NetworkManager.Singleton.StartClient();
50.         InitPlayerName();
51.         Debug.Log("Start Client");
52.         SetActivePanel.SetActive(false);
53.         NetworkManager.Singleton.SceneManager.SetClientSynchronizationMode(LoadSceneMode.Single);
54.  
55.     }
56.  
57.     [ServerRpc(RequireOwnership =false)]
58.     public void WriteStringServerRpc(string name)          
59.     {
60.         PlayerName.Value = name;
61.         PrintNetworkVariableValueClientRpc();
62.         //WriteStringClientRpc(name);                          
63.     }
64.     //testing function
65.     [ClientRpc]
66.     public void PrintNetworkVariableValueClientRpc()
67.     {
68.         Debug.Log(PlayerName.Value);
69.     }
70.  
71.     [ClientRpc]
72.     public void WriteStringClientRpc(string name)
73.     {
74.         PlayerName.Value = name;
75.     }
76.  
77.     // set your name
78.     public void InitPlayerName()
79.     {
80.         YourName = YourName_Field.text;
81.     }
82. }

Code (CSharp):

1. public class LobbyStart : NetworkBehaviour
2. {
3.     // the text that display player name
4.     [SerializeField]
5.     public TextMeshProUGUI PlayerText;
6.  
7.     int i = 1;
8.     private void Awake()
9.     {
10.         PlayerText = GameObject.Find("PlayerName").GetComponent<TextMeshProUGUI>();
11.     }
12.     public void Start2()
13.     {
14.         StartPoint.PlayerName.OnValueChanged += HandleNameChange;           // listener
15.         StartPoint.singleton.WriteStringServerRpc(StartPoint.YourName);
16.         Debug.Log("Current PlayerName is : " + StartPoint.PlayerName.Value);
17.     }
18.     public override void OnNetworkSpawn()
19.     {
20.         StartPoint.PlayerName.OnValueChanged += HandleNameChange;           // listener
21.         StartPoint.singleton.WriteStringServerRpc(StartPoint.YourName);
22.         Debug.Log("Current PlayerName is : " + StartPoint.PlayerName.Value);
23.     }
24.     public override void OnDestroy()
25.     {
26.         Debug.Log("OnDestroy");
27.         StartPoint.PlayerName.OnValueChanged -= HandleNameChange;
28.     }
29.  
30.     public void ChangeNetworkVariableButton()
31.     {
32.         StartPoint.singleton.WriteStringServerRpc("test" + i.ToString());         //called by client , excuted on host/server
33.         i++;
34.     }
35.  
36.     private void HandleNameChange(FixedString64Bytes previousValue, FixedString64Bytes newValue)
37.     {
38.        PlayerText.text = newValue.ToString();
39.         Debug.Log("HandleName Change , " + " The Name is :" + newValue);
40.  
41.     }
42. }

Anything missing?

 

For me I'm using UnityID's and I made "PlayerHUD" script and attached it to player with gameobject "PlayerInfo" as children and that gameobject had textmeshpro component.



I'm not sure how to fix you're code but this was my solution for usernames.

Code (CSharp):

1.  
2. using TMPro;
3. using Unity.Netcode;
4. using UnityEngine;
5. using UnityEngine.SceneManagement;
6. using Unity.Collections;
7. using System.Threading.Tasks;
8. using System.Collections.Generic;
9. using Unity.Services.Authentication;
10. using Unity.Services.CloudSave;
11. using Unity.Services.Core;
12. using Unity.Services.Core.Environments;
13.  
14. public class PlayerHud : NetworkBehaviour
15. {
16.   [SerializeField]
17.   private NetworkVariable<NetworkString> playerNetworkName = new NetworkVariable<NetworkString>();
18.  
19.   [SerializeField]
20.   private bool overlaySet = false;
21.  
22.   [SerializeField]
23.   private string PlayerName;
24.  
25.   public async override void OnNetworkSpawn()
26.   {
27.     Dictionary<string, string> usernameData = await SaveData.LoadAsync(new HashSet<string> {"username"});
28.     PlayerName = usernameData["username"];
29.     Debug.LogWarning($"Got username: {PlayerName}");
30.  
31.     if(!string.IsNullOrEmpty(PlayerName))
32.     {
33.         SetNameServerRpc(PlayerName);
34.         Debug.LogWarning($"Sending RPC");
35.     }
36.       //if(IsServer)
37.       //{
38.         //  playerNetworkName.Value = $"Player {PlayerName}";
39.       //    Debug.LogWarning($"Username Check as Server: {PlayerName}");
40.       //}
41.  
42.   }
43.  
44.   public void SetOverlay()
45.   {
46.       var localPlayerOverlay = gameObject.GetComponentInChildren<TextMeshPro>();
47.       localPlayerOverlay.text = $"{playerNetworkName.Value}";
48.   }
49.  
50.   public void Update()
51.   {
52.       if(!overlaySet && !string.IsNullOrEmpty(playerNetworkName.Value))
53.       {
54.           SetOverlay();
55.           overlaySet = true;
56.       }
57.   }
58.  
59.   [ServerRpc/*(RequireOwnership = false)*/]
60.   public void SetNameServerRpc(string UserName)
61.   {
62.     Debug.LogWarning($"RPC reached");
63.     Debug.LogWarning($"Username Check as Server: {UserName}");
64.     playerNetworkName.Value = $"{UserName}";
65.     Debug.LogWarning($"Changed NetworkVariable to {playerNetworkName.Value}");
66.   }
67. }
68.  

EDIT:
Also I forgot about NetworkString.cs which I imported Assets/Scripts/Shared

Code (CSharp):

1. using Unity.Collections;
2. using Unity.Netcode;
3.  
4. public struct NetworkString : INetworkSerializable
5. {
6.     private FixedString32Bytes info;
7.     public void NetworkSerialize<T>(BufferSerializer<T> serializer) where T : IReaderWriter
8.     {
9.         serializer.SerializeValue(ref info);
10.     }
11.  
12.     public override string ToString()
13.     {
14.         return info.ToString();
15.     }
16.  
17.     public static implicit operator string(NetworkString s) => s.ToString();
18.     public static implicit operator NetworkString(string s) => new NetworkString() { info = new FixedString32Bytes(s) };
19. }
20.  

EDIT: (Again I'm sry)

But I fixed in that code the "" marks in names so I'ma just drop the new code here

Code (CSharp):

1. using TMPro;
2. using Unity.Netcode;
3. using UnityEngine;
4. using UnityEngine.SceneManagement;
5. using Unity.Collections;
6. using System.Threading.Tasks;
7. using System.Collections.Generic;
8. using Unity.Services.Authentication;
9. using Unity.Services.CloudSave;
10. using Unity.Services.Core;
11. using Unity.Services.Core.Environments;
12. using System;
13.  
14. public class PlayerHud : NetworkBehaviour
15. {
16.   [SerializeField]
17.   private NetworkVariable<NetworkString> playerNetworkName = new NetworkVariable<NetworkString>();
18.  
19.   [SerializeField]
20.   private bool overlaySet = false;
21.  
22.   [SerializeField]
23.   private string PlayerName;
24.  
25.   [SerializeField]
26.   private string playerName;
27.  
28.   public async override void OnNetworkSpawn()
29.   {
30.     Dictionary<string, string> usernameData = await SaveData.LoadAsync(new HashSet<string> {"username"});
31.     PlayerName = usernameData["username"];
32.     playerName = PlayerName.Trim( new Char[] {'"', '.' } );
33.     Debug.LogWarning($"Got username: {playerName}");
34.  
35.     if(!string.IsNullOrEmpty(playerName))
36.     {
37.         SetNameServerRpc(playerName);
38.         Debug.LogWarning($"Sending RPC");
39.     }
40.       //if(IsServer)
41.       //{
42.         //  playerNetworkName.Value = $"Player {PlayerName}";
43.       //    Debug.LogWarning($"Username Check as Server: {PlayerName}");
44.       //}
45.  
46.   }
47.  
48.   public void SetOverlay()
49.   {
50.       var localPlayerOverlay = gameObject.GetComponentInChildren<TextMeshPro>();
51.       localPlayerOverlay.text = $"{playerNetworkName.Value}";
52.   }
53.  
54.   public void Update()
55.   {
56.       if(!overlaySet && !string.IsNullOrEmpty(playerNetworkName.Value))
57.       {
58.           SetOverlay();
59.           overlaySet = true;
60.       }
61.   }
62.  
63.   [ServerRpc/*(RequireOwnership = false)*/]
64.   public void SetNameServerRpc(string UserName)
65.   {
66.     Debug.LogWarning($"RPC reached");
67.     Debug.LogWarning($"Username Check as Server: {UserName}");
68.     playerNetworkName.Value = $"{UserName}";
69.     Debug.LogWarning($"Changed NetworkVariable to {playerNetworkName.Value}");
70.   }
71. }
72.  

 

1. private FixedString32Bytes info;
2. public void NetworkSerialize<T>(BufferSerializer<T> serializer) where T : IReaderWriter
3. {
4. serializer.SerializeValue(ref info);

 

I've had a similar issue, and implementing NetworkSerialize for FixedString32Bytes doesn't work because it complains about

error CS0315: The type 'Unity.Collections.FixedString64Bytes' cannot be used as type parameter 'T' in the generic type or method 'BufferSerializer<T>.SerializeValue<T>(ref T, FastBufferWriter.ForPrimitives)'. There is no boxing conversion from 'Unity.Collections.FixedString64Bytes' to 'System.IComparable'.

 

My compiler tells me that "The type 'Unity.Collections.FixedString32Bytes' cannot be used as type parameter 'T' in the generic type or method 'BufferSerializer<T>.SerializeValue<T>(ref T, FastBufferWriter.ForPrimitives)'. There is no boxing conversion from 'Unity.Collections.FixedString32Bytes' to 'System.IComparable'."

 

Starting from pre.8 you have to use

NetworkVariable<ForceNetworkSerializeByMemcpy<FixedString32Bytes>>

instead

 

Hey, in pre.7 I used

Code (CSharp):

1. _name.Value = (FixedString64Bytes) playerNameInput.text;

to write a string to the network variable FixedString64Bytes.
Now with

Code (CSharp):

1. NetworkVariable<ForceNetworkSerializeByMemcpy<FixedString32Bytes>>

it doesn't work anymore. (Cannot convert type 'string' to 'Unity.Netcode.ForceNetworkSerializeByMemcpy<FixedString32Bytes>')

How can you write or read a string from this type?

 

Writing that way should still work.

For writing:

Code (CSharp):

1. _name.Value = new FixedString64Bytes("myString");
2.   // or
3. _name.Value = (FixedString64Bytes) "myString";

For reading:

Code (CSharp):

1. string name = _name.Value.Value.ToString();
2. // or
3. string name = ((FixedString64Bytes)_name.Value).ToString();