Added multiplayer plugin

Assets/Mirror/Editor/NetworkScenePostProcess.cs

@@ -0,0 +1,92 @@
+using System.Collections.Generic;
+using System.Linq;
+using UnityEditor;
+using UnityEditor.Callbacks;
+using UnityEngine;
+
+namespace Mirror
+{
+    public class NetworkScenePostProcess : MonoBehaviour
+    {
+        [PostProcessScene]
+        public static void OnPostProcessScene()
+        {
+            // find all NetworkIdentities in all scenes
+            // => can't limit it to GetActiveScene() because that wouldn't work
+            //    for additive scene loads (the additively loaded scene is never
+            //    the active scene)
+            // => ignore DontDestroyOnLoad scene! this avoids weird situations
+            //    like in NetworkZones when we destroy the local player and
+            //    load another scene afterwards, yet the local player is still
+            //    in the FindObjectsOfType result with scene=DontDestroyOnLoad
+            //    for some reason
+            // => OfTypeAll so disabled objects are included too
+            // => Unity 2019 returns prefabs here too, so filter them out.
+            IEnumerable<NetworkIdentity> identities = Resources.FindObjectsOfTypeAll<NetworkIdentity>()
+                .Where(identity => identity.gameObject.hideFlags != HideFlags.NotEditable &&
+                                   identity.gameObject.hideFlags != HideFlags.HideAndDontSave &&
+                                   identity.gameObject.scene.name != "DontDestroyOnLoad" &&
+                                   !PrefabUtility.IsPartOfPrefabAsset(identity.gameObject));
+
+            foreach (NetworkIdentity identity in identities)
+            {
+                // if we had a [ConflictComponent] attribute that would be better than this check.
+                // also there is no context about which scene this is in.
+                if (identity.GetComponent<NetworkManager>() != null)
+                {
+                    Debug.LogError("NetworkManager has a NetworkIdentity component. This will cause the NetworkManager object to be disabled, so it is not recommended.");
+                }
+
+                // not spawned before?
+                //  OnPostProcessScene is called after additive scene loads too,
+                //  and we don't want to set main scene's objects inactive again
+                if (!identity.isClient && !identity.isServer)
+                {
+                    // valid scene object?
+                    //   otherwise it might be an unopened scene that still has null
+                    //   sceneIds. builds are interrupted if they contain 0 sceneIds,
+                    //   but it's still possible that we call LoadScene in Editor
+                    //   for a previously unopened scene.
+                    //   (and only do SetActive if this was actually a scene object)
+                    if (identity.sceneId != 0)
+                    {
+                        PrepareSceneObject(identity);
+                    }
+                    // throwing an exception would only show it for one object
+                    // because this function would return afterwards.
+                    else Debug.LogError("Scene " + identity.gameObject.scene.path + " needs to be opened and resaved, because the scene object " + identity.name + " has no valid sceneId yet.");
+                }
+            }
+        }
+
+        static void PrepareSceneObject(NetworkIdentity identity)
+        {
+            // set scene hash
+            identity.SetSceneIdSceneHashPartInternal();
+
+            // disable it
+            // note: NetworkIdentity.OnDisable adds itself to the
+            //       spawnableObjects dictionary (only if sceneId != 0)
+            identity.gameObject.SetActive(false);
+
+            // safety check for prefabs with more than one NetworkIdentity
+#if UNITY_2018_2_OR_NEWER
+            GameObject prefabGO = PrefabUtility.GetCorrespondingObjectFromSource(identity.gameObject);
+#else
+                        GameObject prefabGO = PrefabUtility.GetPrefabParent(identity.gameObject);
+#endif
+            if (prefabGO)
+            {
+#if UNITY_2018_3_OR_NEWER
+                GameObject prefabRootGO = prefabGO.transform.root.gameObject;
+#else
+                            GameObject prefabRootGO = PrefabUtility.FindPrefabRoot(prefabGO);
+#endif
+                if (prefabRootGO != null && prefabRootGO.GetComponentsInChildren<NetworkIdentity>().Length > 1)
+                {
+                    Debug.LogWarningFormat("Prefab '{0}' has several NetworkIdentity components attached to itself or its children, this is not supported.", prefabRootGO.name);
+                }
+            }
+        }
+    }
+}