feat: Added a way to safely access GlobalObjectIdHash via PrefabHashId [MTT-1645] (#2437)

* Added a way to access the GlobalObjectIdHash via PrefabHashId.
* Added PrefabHashId tests.

---------

Co-authored-by: Fatih Mar <[email protected]>
Co-authored-by: Noel Stephens <[email protected]>
Co-authored-by: NoelStephensUnity <[email protected]>

Author: 3 people

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -7,8 +7,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 Additional documentation and release notes are available at [Multiplayer Documentation](https://docs-multiplayer.unity3d.com).
 
 ## [Unreleased]
+
 ### Added
 
+- Added a way to access the GlobalObjectIdHash via PrefabIdHash for use in the Connection Approval Callback. (#2437)
 - Added `NetworkTransform.UseHalfFloatPrecision` property that, when enabled, will use half float values for position, rotation, and scale. This yields a 50% bandwidth savings a the cost of precision. (#2388)
 - Added `NetworkTransform.UseQuaternionSynchronization` property that, when enabled, will synchronize the entire quaternion. (#2388)
 - Added `NetworkTransform.UseQuaternionCompression` property that, when enabled, will use a smallest three implementation reducing a full quaternion synchronization update to the size of an unsigned integer. (#2388)

com.unity.netcode.gameobjects/Runtime/Core/NetworkObject.cs

@@ -17,6 +17,28 @@ public sealed class NetworkObject : MonoBehaviour
         [SerializeField]
         internal uint GlobalObjectIdHash;
 
+        /// <summary>
+        /// Gets the Prefab Hash Id of this object if the object is registerd as a prefab otherwise it returns 0
+        /// </summary>
+        [HideInInspector]
+        public uint PrefabIdHash
+        {
+            get
+            {
+                foreach (var prefab in NetworkManager.NetworkConfig.Prefabs.Prefabs)
+                {
+                    if (prefab.Prefab == gameObject)
+                    {
+                        return GlobalObjectIdHash;
+                    }
+                }
+
+                return 0;
+            }
+        }
+
+        private bool m_IsPrefab;
+
 #if UNITY_EDITOR
         private void OnValidate()
         {

com.unity.netcode.gameobjects/Tests/Runtime/NetworkObject/NetworkObjectPropertyTests.cs

@@ -0,0 +1,45 @@
+using NUnit.Framework;
+using Unity.Netcode.TestHelpers.Runtime;
+using UnityEngine;
+
+namespace Unity.Netcode.RuntimeTests
+{
+    /// <summary>
+    /// Tests properties of NetworkObject for proper functionality.
+    /// </summary>
+    public class NetworkObjectPropertyTests : NetcodeIntegrationTest
+    {
+        protected override int NumberOfClients => 1;
+
+        private NetworkObject m_TestPrefabNetworkObject;
+
+        protected override void OnServerAndClientsCreated()
+        {
+            // create prefab and get the NetworkObject component attached to it
+            m_TestPrefabNetworkObject = CreateNetworkObjectPrefab("TestObject").GetComponent<NetworkObject>();
+        }
+
+        /// <summary>
+        /// Tests PrefabHashId returns correctly when the NetworkObject is not a prefab.
+        /// </summary>
+        [Test]
+        public void TestPrefabHashIdPropertyNotAPrefab()
+        {
+            const uint kInvalidPrefabHashId = 0;
+
+            var gameObject = new GameObject("TestObject");
+            var networkObject = gameObject.AddComponent<NetworkObject>();
+            Assert.AreEqual(kInvalidPrefabHashId, networkObject.PrefabIdHash);
+        }
+
+        /// <summary>
+        /// Tests PrefabHashId returns correctly when the NetworkObject is a prefab.
+        /// </summary>
+        /// <returns></returns>
+        [Test]
+        public void TestPrefabHashIdPropertyIsAPrefab()
+        {
+            Assert.AreEqual(m_TestPrefabNetworkObject.GlobalObjectIdHash, m_TestPrefabNetworkObject.PrefabIdHash);
+        }
+    }
+}