Class SyncVarAttribute

[SyncVar] is an attribute that can be put on member variables of NetworkBehaviour classes. These variables will have their values sychronized from the server to clients in the game that are in the ready state.

Setting the value of a [SyncVar] marks it as dirty, so it will be sent to clients at the end of the current frame. Only simple values can be marked as [SyncVars]. The type of the SyncVar variable cannot be from an external DLL or assembly.

using UnityEngine;
using UnityEngine.Networking;

public class Ship : NetworkBehaviour
{
   [SyncVar]
   public int health = 100;

   [SyncVar]
   public float energy = 100;
}

The allowed SyncVar types are:

• Basic type (byte, int, float, string, UInt64, etc)
• Built-in Unity math type (Vector3, Quaternion, etc),
• Structs containing allowable types.

Inheritance

Object

Attribute

SyncVarAttribute

Namespace: UnityEngine.Networking

Syntax

[AttributeUsage(AttributeTargets.Field)]
[Obsolete("The high level API classes are deprecated and will be removed in the future.")]
public class SyncVarAttribute : Attribute, _Attribute

Fields

hook

The hook attribute can be used to specify a function to be called when the sync var changes value on the client.

This ensures that all clients receive the proper variables from other clients.

//Attach this to the GameObject you would like to spawn (the player).
//Make sure to create a NetworkManager with an HUD component in your Scene. To do this, create a GameObject, click on it, and click on the Add Component button in the Inspector window.  From there, Go to Network>NetworkManager and Network>NetworkManagerHUD respectively.
//Assign the GameObject you would like to spawn in the NetworkManager.
//Start the server and client for this to work.

//Use this script to send and update variables between Networked GameObjects
using UnityEngine;
using UnityEngine.Networking;

public class Health : NetworkBehaviour
{
   public const int m_MaxHealth = 100;

   //Detects when a health change happens and calls the appropriate function
   [SyncVar(hook = "OnChangeHealth")]
   public int m_CurrentHealth = m_MaxHealth;
   public RectTransform healthBar;

   public void TakeDamage(int amount)
   {
       if (!isServer)
           return;
       //Decrease the "health" of the GameObject
       m_CurrentHealth -= amount;
       //Make sure the health doesn't go below 0
       if (m_CurrentHealth <= 0)
       {
           m_CurrentHealth = 0;
       }
   }

   void Update()
   {
       //If the space key is pressed, decrease the GameObject's own "health"
       if (Input.GetKey(KeyCode.Space))
       {
           if (isLocalPlayer)
               CmdTakeHealth();
       }
   }

   void OnChangeHealth(int health)
   {
       healthBar.sizeDelta = new Vector2(health, healthBar.sizeDelta.y);
   }

   //This is a Network command, so the damage is done to the relevant GameObject
   [Command]
   void CmdTakeHealth()
   {
       //Apply damage to the GameObject
       TakeDamage(2);
   }
}

Declaration

public string hook

Field Value

Type	Description
String