The NetworkIdentity identifies objects across the network, between server and clients. Its primary data is a NetworkInstanceId which is allocated by the server and then set on clients. This is used in network communications to be able to lookup game objects on different machines.
The NetworkIdentity is used to synchronize information in the object with the network. Only the server should create instances of objects which have NetworkIdentity as otherwise they will not be properly connected to the system.
For complex objects with a heirarchy of subcomponents, the NetworkIdentity must be on the root of the heirarchy. It is not supported to have multiple NetworkIdentity components on subcomponents of a heirarchy.
NetworkBehaviour scripts require a NetworkIdentity on the game object to be able to function.
The NetworkIdentity manages the dirty state of the NetworkBehaviours of the object. When it discovers that NetworkBehaviours are dirty, it causes an update packet to be created and sent to clients.
The flow for serialization updates managed by the NetworkIdentity is:
* Each NetworkBehaviour has a dirty mask. This mask is available inside OnSerialize as syncVarDirtyBits
* Each SyncVar in a NetworkBehaviour script is assigned a bit in the dirty mask.
* Changing the value of SyncVars causes the bit for that SyncVar to be set in the dirty mask
* Alternatively, calling SetDirtyBit() writes directly to the dirty mask
* NetworkIdentity objects are checked on the server as part of it’s update loop
* If any NetworkBehaviours on a NetworkIdentity are dirty, then an UpdateVars packet is created for that object
* The UpdateVars packet is populated by calling OnSerialize on each NetworkBehaviour on the object
* NetworkBehaviours that are NOT dirty write a zero to the packet for their dirty bits
* NetworkBehaviours that are dirty write their dirty mask, then the values for the SyncVars that have changed
* If OnSerialize returns true for a NetworkBehaviour, the dirty mask is reset for that NetworkBehaviour, so it will not send again
until its value changes.
* The UpdateVars packet is sent to ready clients that are observing the object
On the client:
* an UpdateVars packet is received for an object
* The OnDeserialize function is called for each NetworkBehaviour script on the object
* Each NetworkBehaviour script on the object reads a dirty mask.
* If the dirty mask for a NetworkBehaviour is zero, the OnDeserialize functions returns without reading any more
* If the dirty mask is non-zero value, then the OnDeserialize function reads the values for the SyncVars that correspond to the dirty bits that are set
* If there are SyncVar hook functions, those are invoked with the value read from the stream.
| clientAuthorityCallback | A callback that can be populated to be notified when the client-authority state of objects changes. |
| assetId | Unique identifier used to find the source assets when server spawns the on clients. |
| clientAuthorityOwner | The client that has authority for this object. This will be null if no client has authority. |
| connectionToClient | The connection associated with this NetworkIdentity. This is only valid for player objects on the server. |
| connectionToServer | The UConnection associated with this NetworkIdentity. This is only valid for player objects on a local client. |
| hasAuthority | This returns true if this object is the authoritative version of the object in the distributed network application. |
| isClient | Returns true if running as a client and this object was spawned by a server. |
| isLocalPlayer | This returns true if this object is the one that represents the player on the local machine. |
| isServer | Returns true if running as a server, which spawned the object. |
| localPlayerAuthority | localPlayerAuthority means that the client of the "owning" player has authority over their own player object. |
| netId | Unique identifier for this particular object instance, used for tracking objects between networked clients and the server. |
| observers | The set of network connections (players) that can see this object. |
| playerControllerId | The id of the player associated with this GameObject. |
| sceneId | A unique identifier for NetworkIdentity objects within a scene. |
| serverOnly | Flag to make this object only exist when the game is running as a server (or host). |
| AssignClientAuthority | This assigns control of an object to a client via the client's NetworkConnection. |
| ForceSceneId | Force the scene ID to a specific value. |
| RebuildObservers | This causes the set of players that can see this object to be rebuild. The OnRebuildObservers callback function will be invoked on each NetworkBehaviour. |
| RemoveClientAuthority | Removes ownership for an object for a client by its conneciton. |
| ClientAuthorityCallback | The delegate type for the clientAuthorityCallback. |
| enabled | Enabled Behaviours are Updated, disabled Behaviours are not. |
| isActiveAndEnabled | Has the Behaviour had enabled called. |
| gameObject | The game object this component is attached to. A component is always attached to a game object. |
| tag | The tag of this game object. |
| transform | The Transform attached to this GameObject. |
| runInEditMode | Allow a specific instance of a MonoBehaviour to run in edit mode (only available in the editor). |
| useGUILayout | Disabling this lets you skip the GUI layout phase. |
| hideFlags | Should the object be hidden, saved with the scene or modifiable by the user? |
| name | The name of the object. |
| BroadcastMessage | Calls the method named methodName on every MonoBehaviour in this game object or any of its children. |
| CompareTag | Is this game object tagged with tag ? |
| GetComponent | Returns the component of Type type if the game object has one attached, null if it doesn't. |
| GetComponentInChildren | Returns the component of Type type in the GameObject or any of its children using depth first search. |
| GetComponentInParent | Returns the component of Type type in the GameObject or any of its parents. |
| GetComponents | Returns all components of Type type in the GameObject. |
| GetComponentsInChildren | Returns all components of Type type in the GameObject or any of its children. |
| GetComponentsInParent | Returns all components of Type type in the GameObject or any of its parents. |
| SendMessage | Calls the method named methodName on every MonoBehaviour in this game object. |
| SendMessageUpwards | Calls the method named methodName on every MonoBehaviour in this game object and on every ancestor of the behaviour. |
| CancelInvoke | Cancels all Invoke calls on this MonoBehaviour. |
| Invoke | Invokes the method methodName in time seconds. |
| InvokeRepeating | Invokes the method methodName in time seconds, then repeatedly every repeatRate seconds. |
| IsInvoking | Is any invoke on methodName pending? |
| StartCoroutine | Starts a coroutine. |
| StopAllCoroutines | Stops all coroutines running on this behaviour. |
| StopCoroutine | Stops the first coroutine named methodName, or the coroutine stored in routine running on this behaviour. |
| GetInstanceID | Returns the instance id of the object. |
| ToString | Returns the name of the game object. |
| Logs message to the Unity Console (identical to Debug.Log). | |
| Destroy | Removes a gameobject, component or asset. |
| DestroyImmediate | Destroys the object obj immediately. |
| DontDestroyOnLoad | Makes the object target not be destroyed automatically when loading a new scene. |
| FindObjectOfType | Returns the first active loaded object of Type type. |
| FindObjectsOfType | Returns a list of all active loaded objects of Type type. |
| Instantiate | Clones the object original and returns the clone. |
| bool | Does the object exist? |
| operator != | Compares if two objects refer to a different object. |
| operator == | Compares two object references to see if they refer to the same object. |
| Awake | Awake is called when the script instance is being loaded. |
| FixedUpdate | This function is called every fixed framerate frame, if the MonoBehaviour is enabled. |
| LateUpdate | LateUpdate is called every frame, if the Behaviour is enabled. |
| OnAnimatorIK | Callback for setting up animation IK (inverse kinematics). |
| OnAnimatorMove | Callback for processing animation movements for modifying root motion. |
| OnApplicationFocus | Sent to all GameObjects when the player gets or loses focus. |
| OnApplicationPause | Sent to all GameObjects when the application pauses. |
| OnApplicationQuit | Sent to all game objects before the application is quit. |
| OnAudioFilterRead | If OnAudioFilterRead is implemented, Unity will insert a custom filter into the audio DSP chain. |
| OnBecameInvisible | OnBecameInvisible is called when the renderer is no longer visible by any camera. |
| OnBecameVisible | OnBecameVisible is called when the renderer became visible by any camera. |
| OnCollisionEnter | OnCollisionEnter is called when this collider/rigidbody has begun touching another rigidbody/collider. |
| OnCollisionEnter2D | Sent when an incoming collider makes contact with this object's collider (2D physics only). |
| OnCollisionExit | OnCollisionExit is called when this collider/rigidbody has stopped touching another rigidbody/collider. |
| OnCollisionExit2D | Sent when a collider on another object stops touching this object's collider (2D physics only). |
| OnCollisionStay | OnCollisionStay is called once per frame for every collider/rigidbody that is touching rigidbody/collider. |
| OnCollisionStay2D | Sent each frame where a collider on another object is touching this object's collider (2D physics only). |
| OnConnectedToServer | Called on the client when you have successfully connected to a server. |
| OnControllerColliderHit | OnControllerColliderHit is called when the controller hits a collider while performing a Move. |
| OnDestroy | This function is called when the MonoBehaviour will be destroyed. |
| OnDisable | This function is called when the behaviour becomes disabled () or inactive. |
| OnDisconnectedFromServer | Called on the client when the connection was lost or you disconnected from the server. |
| OnDrawGizmos | Implement OnDrawGizmos if you want to draw gizmos that are also pickable and always drawn. |
| OnDrawGizmosSelected | Implement OnDrawGizmosSelected to draw a gizmo if the object is selected. |
| OnEnable | This function is called when the object becomes enabled and active. |
| OnFailedToConnect | Called on the client when a connection attempt fails for some reason. |
| OnFailedToConnectToMasterServer | Called on clients or servers when there is a problem connecting to the MasterServer. |
| OnGUI | OnGUI is called for rendering and handling GUI events. |
| OnJointBreak | Called when a joint attached to the same game object broke. |
| OnJointBreak2D | Called when a Joint2D attached to the same game object breaks. |
| OnMasterServerEvent | Called on clients or servers when reporting events from the MasterServer. |
| OnMouseDown | OnMouseDown is called when the user has pressed the mouse button while over the GUIElement or Collider. |
| OnMouseDrag | OnMouseDrag is called when the user has clicked on a GUIElement or Collider and is still holding down the mouse. |
| OnMouseEnter | Called when the mouse enters the GUIElement or Collider. |
| OnMouseExit | Called when the mouse is not any longer over the GUIElement or Collider. |
| OnMouseOver | Called every frame while the mouse is over the GUIElement or Collider. |
| OnMouseUp | OnMouseUp is called when the user has released the mouse button. |
| OnMouseUpAsButton | OnMouseUpAsButton is only called when the mouse is released over the same GUIElement or Collider as it was pressed. |
| OnNetworkInstantiate | Called on objects which have been network instantiated with Network.Instantiate. |
| OnParticleCollision | OnParticleCollision is called when a particle hits a Collider. |
| OnParticleTrigger | OnParticleTrigger is called when any particles in a particle system meet the conditions in the trigger module. |
| OnPlayerConnected | Called on the server whenever a new player has successfully connected. |
| OnPlayerDisconnected | Called on the server whenever a player disconnected from the server. |
| OnPostRender | OnPostRender is called after a camera finished rendering the scene. |
| OnPreCull | OnPreCull is called before a camera culls the scene. |
| OnPreRender | OnPreRender is called before a camera starts rendering the scene. |
| OnRenderImage | OnRenderImage is called after all rendering is complete to render image. |
| OnRenderObject | OnRenderObject is called after camera has rendered the scene. |
| OnSerializeNetworkView | Used to customize synchronization of variables in a script watched by a network view. |
| OnServerInitialized | Called on the server whenever a Network.InitializeServer was invoked and has completed. |
| OnTransformChildrenChanged | This function is called when the list of children of the transform of the GameObject has changed. |
| OnTransformParentChanged | This function is called when the parent property of the transform of the GameObject has changed. |
| OnTriggerEnter | OnTriggerEnter is called when the Collider other enters the trigger. |
| OnTriggerEnter2D | Sent when another object enters a trigger collider attached to this object (2D physics only). |
| OnTriggerExit | OnTriggerExit is called when the Collider other has stopped touching the trigger. |
| OnTriggerExit2D | Sent when another object leaves a trigger collider attached to this object (2D physics only). |
| OnTriggerStay | OnTriggerStay is called once per frame for every Collider other that is touching the trigger. |
| OnTriggerStay2D | Sent each frame where another object is within a trigger collider attached to this object (2D physics only). |
| OnValidate | This function is called when the script is loaded or a value is changed in the inspector (Called in the editor only). |
| OnWillRenderObject | OnWillRenderObject is called for each camera if the object is visible. |
| Reset | Reset to default values. |
| Start | Start is called on the frame when a script is enabled just before any of the Update methods is called the first time. |
| Update | Update is called every frame, if the MonoBehaviour is enabled. |