Struct GhostDespawnSystem
Present only in client worlds. Responsible for destroying spawned ghosts when a despawn request/command is received from the server.
Clients are not responsible for destroying ghost entities (and thus should never). The server is responsible for notifying the client about which ghosts should be destroyed (as part of the snapshot protocol).
When a despawn command is received, the ghost entity is queued into a despawn queue. Two distinct despawn queues exist: one for interpolated, and one for the predicted ghosts.
The above distinction is necessary because interpolated ghosts timeline (InterpolationTick) is in the past in respect to both the server and client timeline (the current simulated tick). When a snapshot with a despawn command (for an interpolated ghost) is received, the server tick at which the entity has been destroyed (on the server) may be still in the future (for this client), and therefore the client must wait until the InterpolationTick is greater or equal the despawning tick to actually despawn the ghost.
Predicted entities, on the other hand, can be despawned only when the current ServerTick is greater than or equal to the despawn tick of the server. Therefore, if the client is running ahead (as it should be), predicted ghosts will be destroyed as soon as their despawn request is pulled out of the snapshot (i.e. later on that same frame).
Implements
Inherited Members
Namespace: Unity.NetCode
Assembly: Unity.NetCode.dll
Syntax
[BurstCompile]
[UpdateInGroup(typeof(GhostSimulationSystemGroup))]
[WorldSystemFilter(WorldSystemFilterFlags.ClientSimulation|WorldSystemFilterFlags.ThinClientSimulation, WorldSystemFilterFlags.Default)]
public struct GhostDespawnSystem : ISystem, ISystemCompilerGeneratedMethods
OnCreate(ref SystemState)
Called when this system is created.
Declaration
public void OnCreate(ref SystemState state)Parameters
| Type | Name | Description |
|---|---|---|
| SystemState | state | The Unity.Entities.SystemState backing this system instance |
Remarks
Implement an OnCreate function to set up system resources when it is created.
OnCreate is invoked before the the first time Unity.Entities.ISystemStartStop.OnStartRunning(ref Unity.Entities.SystemState)
and Unity.Entities.ISystem.OnUpdate(ref Unity.Entities.SystemState) are invoked.
OnCreateForCompiler(ref SystemState)
Generated by compilation pipeline and used internally.
Declaration
public void OnCreateForCompiler(ref SystemState state)Parameters
| Type | Name | Description |
|---|---|---|
| SystemState | state | The Unity.Entities.SystemState backing this system instance |
OnDestroy(ref SystemState)
Called when this system is destroyed.
Declaration
[BurstCompile]
public void OnDestroy(ref SystemState state)Parameters
| Type | Name | Description |
|---|---|---|
| SystemState | state | The Unity.Entities.SystemState backing this system instance |
Remarks
Systems are destroyed when the application shuts down, the World is destroyed, or you call Unity.Entities.World.DestroySystem(Unity.Entities.SystemHandle). In the Unity Editor, system destruction occurs when you exit Play Mode and when scripts are reloaded.
OnUpdate(ref SystemState)
Implement OnUpdate to perform the major work of this system.
Declaration
[BurstCompile]
public void OnUpdate(ref SystemState state)Parameters
| Type | Name | Description |
|---|---|---|
| SystemState | state | The Unity.Entities.SystemState backing this system instance |
Remarks
By default, the system invokes `OnUpdate` once every frame on the main thread. To skip OnUpdate if all of the system's [EntityQueries] are empty, use the [RequireMatchingQueriesForUpdateAttribute]. To limit when OnUpdate is invoked, you can specify components that must exist, or queries that match specific Entities. To do this, call Unity.Entities.SystemState.RequireForUpdate<T>() or Unity.Entities.SystemState.RequireForUpdate(Unity.Entities.EntityQuery) in the system's OnCreate method. For more information, see Unity.Entities.SystemState.ShouldRunSystem().
You can instantiate and schedule an Unity.Entities.IJobChunk instance; you can use the [C# Job System] or you can perform work on the main thread. If you call Unity.Entities.EntityManager methods that perform structural changes on the main thread, be sure to arrange the system order to minimize the performance impact of the resulting [sync points].
[sync points]: xref:concepts-structural-changes
[C# Job System]: https://docs.unity3d.com/Manual/JobSystem.html
[EntityQueries]: xref:Unity.Entities.EntityQuery
[RequireMatchingQueriesForUpdateAttribute]: xref:Unity.Entities.RequireMatchingQueriesForUpdateAttribute