Question Unity Netcode throws error.

Hi,
I was following Unity Netcode getting started tutorial "https://docs.unity3d.com/Packages/com.unity.netcode@0.6/manual/getting-started.html"

Instead of using "Convert to Client Server Entity" I used subscene workflow.
Then all the other scripts for system were using ComponentSystem which I replaced with the SystemBase class and this required me to replace all the PostUpdateCommands with the EntityCommandBuffer.

Now when I run the code everything looks fine but I get the runtime exceptions in the console as can be seen in the screenshot.




One of the Systems was GoInGameServerSystem. I am pasting its code here (I made similar changes to other systems as well):

using System;
using Unity.NetCode;
using Unity.Entities;
// When server receives go in game request, go in game and delete request
[UpdateInGroup(typeof(ServerSimulationSystemGroup))]
public class GoInGameServerSystem : SystemBase
{
EndSimulationEntityCommandBufferSystem _mECB;
protected override void OnCreate()
{
_mECB = World.GetOrCreateSystem<EndSimulationEntityCommandBufferSystem>();
}
protected override void OnUpdate()
{
var ecb = _mECB.CreateCommandBuffer();//.AsParallelWriter();
Entities.WithNone<SendRpcCommandRequestComponent>().ForEach((Entity reqEnt, ref GoInGameRequest req, ref ReceiveRpcCommandRequestComponent reqSrc) =>
{
//PostUpdateCommands.AddComponent<NetworkStreamInGame>(reqSrc.SourceConnection);
//UnityEngine.Debug.Log(String.Format("Server setting connection {0} to in game", EntityManager.GetComponentData<NetworkIdComponent>(reqSrc.SourceConnection).Value));
//var ghostCollection = GetSingletonEntity<GhostPrefabCollectionComponent>();
//var prefab = Entity.Null;
//var prefabs = EntityManager.GetBuffer<GhostPrefabBuffer>(ghostCollection);
//for (int ghostId = 0; ghostId < prefabs.Length; ++ghostId)
//{
// if (EntityManager.HasComponent<MovableCubeData>(prefabs[ghostId].Value))
// prefab = prefabs[ghostId].Value;
//}
//var player = EntityManager.Instantiate(prefab);
//EntityManager.SetComponentData(player, new GhostOwnerComponent { NetworkId = EntityManager.GetComponentData<NetworkIdComponent>(reqSrc.SourceConnection).Value });
//PostUpdateCommands.AddBuffer<CubeInput>(player);
//PostUpdateCommands.SetComponent(reqSrc.SourceConnection, new CommandTargetComponent { targetEntity = player });
//PostUpdateCommands.DestroyEntity(reqEnt);
ecb.AddComponent<NetworkStreamInGame>(reqSrc.SourceConnection);
UnityEngine.Debug.Log(String.Format("Server setting connection {0} to in game", EntityManager.GetComponentData<NetworkIdComponent>(reqSrc.SourceConnection).Value));
var ghostCollection = GetSingletonEntity<GhostPrefabCollectionComponent>();
var prefab = Entity.Null;
var prefabs = EntityManager.GetBuffer<GhostPrefabBuffer>(ghostCollection);
for (int ghostId = 0; ghostId < prefabs.Length; ++ghostId)
{
if (EntityManager.HasComponent<MovableCubeData>(prefabs[ghostId].Value))
prefab = prefabs[ghostId].Value;
}
//var player = EntityManager.Instantiate(prefab);
var player = ecb.Instantiate(prefab);
EntityManager.SetComponentData(player, new GhostOwnerComponent { NetworkId = EntityManager.GetComponentData<NetworkIdComponent>(reqSrc.SourceConnection).Value });
ecb.AddBuffer<CubeInput>(player);
ecb.SetComponent(reqSrc.SourceConnection, new CommandTargetComponent { targetEntity = player });
ecb.DestroyEntity(reqEnt);
}).WithoutBurst().Run();
_mECB.AddJobHandleForProducer(this.Dependency);
}
}


Can someone look into this and provide some guidance.

Regards

 

Thanks for the response.
Now when I think about it that is actually right.

But the problem that I am facing is that the Netcode example uses following for the same
//var player = EntityManager.Instantiate(prefab);
//EntityManager.SetComponentData(player, new GhostOwnerComponent { NetworkId = EntityManager.GetComponentData<NetworkIdComponent>(reqSrc.SourceConnection).Value });
//PostUpdateCommands.AddBuffer<CubeInput>(player);

but if I put this inside the foreach loop (i.e., var player = EntityManager.Instantiate(prefab)) then it gives me error for structural changes inside the forEach.. I used ecb and that removed the error but now I realize it was completely wrong as you have already mentioned.
Is there any other way? or I will have to go with WithStructuralChanges?
(that would mean I will need to understand how that will impact the whole example as I have just started to try DOTS)

 

This is awesome.. Thanks I will follow this one now...