Struct GhostSendSystem

System present only for servers worlds, and responsible to replicate ghost entities to the clients. The GhostSendSystem is one of the most complex system of the whole package and heavily rely on multi-thread jobs to dispatch ghosts to all connection as much as possible in parallel.

Ghosts entities are replicated by sending a 'snapshot' of their state to the clients, at NetworkTickRate frequency. Snaphosts are streamed to the client when their connection is tagged with a NetworkStreamInGame component (we usually refere a connection with that tag as "in-game"), and transmitted using an unrealiable channel. To save bandwith, snapshosts are delta-compressed against the latest reported ones received by the client. By default, up to 3 baseline are used to delta-compress the data, by using a predictive compression scheme (see GhostDeltaPredictor). It is possible to reduce the number of baseline used (and CPU cycles) using the GhostSendSystemData settings.

The GhostSendSystem is designed to send to each connection one single packet per network update. By default, the system will try to replicate to the clients all the existing ghost present in the world. When all ghosts cannot be serialized into the same packet, the enties are prioritized by their importance.

The base ghost importance can be set at authoring time on the prefab (Unity.NetCode.GhostAuthoringComponent); At runtime the ghost importance is scaled based on:

- age (the last time the entities has been sent)

- scaled by distance, (see GhostConnectionPosition, GhostDistanceImportance

- scaled by custom scaling (see GhostImportance

Ghost entities are replicated on "per-chunk" basis; all ghosts for the same chunk, are replicated together. The importance, as well as the importance scaling, apply to whole chunk.

The send system can also be configured to send multiple ghost packets per frame and to to use snaphost larger than the MaxMessageSize. In that case, the snapshot packet is sent using another unreliable channel, setup with a Unity.Networking.Transport.FragmentationPipelineStage.

Implements
ISystemCompilerGenerated
Inherited Members
Namespace: Unity.NetCode
Assembly: Unity.NetCode.dll
Syntax
[WorldSystemFilter(WorldSystemFilterFlags.ServerSimulation, WorldSystemFilterFlags.Default)]
[UpdateInGroup(typeof(SimulationSystemGroup), OrderLast = true)]
[UpdateAfter(typeof(EndSimulationEntityCommandBufferSystem))]
[BurstCompile]
public struct GhostSendSystem : ISystem, ISystemCompilerGenerated

Implements

Unity.Entities.ISystemCompilerGenerated

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