DOTS Multiplayer discussion

@timjohansson Thank you for the answer!
So RPC's don't share packed size with entities snapshots. Did I get it right?

What is the best possible way to organize Response/Request flow for information that will be rarely sent? The question more about the best way of using the unity transport layer and what is better, create a separate driver or hook up into NetworkStreamRecieveSystem.
Because, I've found that using entities RPC it's not very convenient, especially for sending arrays and writing all boilerplate code only for sending a message over the network.

 

Thank you @timjohansson !

 

Sorry to keep bothering @Jawsarn but I am a bit confused on how for #1 the code snippet showed that they are using predicted when spawning.

Code (CSharp):

1.  
2.                else
3.                 {
4.                     bulletSpawnArchetype = EntityManager.CreateArchetype(
5.                         ComponentType.ReadWrite<PredictedGhostSpawnRequestComponent>(),
6.                         ComponentType.ReadWrite<BulletSnapshotData>());
7.                 }

That ^ "else" statement is run on clients. Why is an Archetype needed with those components fort predicting a spawn?

(cc @timjohansson )

 

@timjohansson what is the purpose of the CalculateVelocityJob in the asteroids sample?

 

thank you!

 

@timjohansson Thank you a lot!

 

@timjohansson I've posted the problem in some other thread and on issues a while ago without answer. But do you know about the problem of the serializers causing "InvalidProgramException: Passing an argument of size '10568'." and when it will be fixed? Right now I have to manually go update the IGhostSerializers to remove duplicate ComponentDataFromEntity (as child entities using same component create redudant ComponentDataFromEntity variables) when I generate ghosts.

 

I wasn't even aware that such a restriction existed before the exception popped up.
Can we not fix that by making the GhostSerializerCollection unmanaged and just pass a pointer around for it?

 

@timjohansson

Thank you for updating the sample projects! huge help!

1. Is there a way to add a DynamicBuffer of CommandData directly onto a Gameobject using [GenerateAuthoringComponent] ?

Currently I am still using:

Code (CSharp):

1. public class PlayerCommandDataAuthoringComponent : MonoBehaviour, IConvertGameObjectToEntity
2. {
3.     public void Convert(Entity entity, EntityManager dstManager, GameObjectConversionSystem conversionSystem)
4.     {
5.         dstManager.AddBuffer<PlayerCommandData>(entity);
6.     }
7. }

Not the biggest deal, but thought I would check for consistency in my project.

2. Do I need to add Current Simulated Position/Rotation to all my Ghost objects? In the Asteroids sample project they are on ships/bullets/asteroids but I do not see them being called explicitly in the code. What happens if these are not included on Ghost objects?

(cc @Jawsarn )

 

You rock thank you @timjohansson !

 

how do I disable fixed client tick rate?

In the sample project GameMain.cs I see:

`world.EntityManager.CreateEntity(typeof(FixedClientTickRate));`

What should I be using instead?

Edit, I found the solution but thought I would leave the comment in case anyone else was wondering:

`world.EntityManager.CreateEntity(typeof(ClientServerTickRate));`

 

@timjohansson

I am running into issues when trying to deploy a WebGL build.



I am guessing the issue is WebRTC not supporting the sockets used by the current Netcode.

What would be the approach to get this working or is it a non-starter to build multiplayer games using Unity ECS/Netcode?

I am guessing there needs to be some kind of an

if (WebGL build) then use...[insert WebRTC interface here]

at the Transport low level code.

Or is this an il2cpp issue?

 

Hello everyone!
Help me please, I need create thin clients and generate fake input.
1) Create. I now way by create custom bootstrap. Are there any other ways ?
2) Fake input. I managed to make input from the server side ( generate physical parameters and apply thees, objects are moving ), but i need to make input from client side. I think, i need to write fake data to Input buffer in ClientSimulationSystemGroup at thin world, but i can't do this, because i can't find at what entity i must write buffer.

 

Thank you very much!!! You helped me a lot!!!

 

How many players are available in current version on NetCode ? I was extend your example with thin clients and fake input. Conducted tests show that more than 64 clients do not work correctly. Entities for new client are created at server and old clients, but not created at new client. Therefor new client don't show players, don't generate fake input - at server and other clients new players are not moving.

 

I recorded a video for you, please watch.

 

Hello @timjohansson ! Is there any way to know when Ghost on the client will be despawned? The problem that I want to solve is to clean up references to an entity that will be destroyed.

 

1. In my game(spaceship flight simulator) I need to implement my own physics so basically to make smoother movements I need for example velocity(but also a direction vector and possibly some other variables for my simulator physics) so i can gradually increase/decrease the value. My question is should velocity be ghost authoring component or should i maintain on server and client along with snapshots velocity values calculated at fixed timestep (in current tick we use value that refer to previous tick/snapshot so newVelocityValue=prevSnapshotVelocityValue+acceleration*fixedTimestep - ofc this is based on user input)? What is the best approach for flight simulator game i want to make? So on server we would have special buffers attached to each player's entity with velocity value and those entities we create when snapshot is created and destroyed when the snapshot they refer to are destroyed. I already implemented velocity as ghost component and it works well although i tested the game only locally(i still use netcode 0.1 in my game).
2nd approach would probably decrease the size of the snapshot?

2. In a similar game i believe they used fixed timestep also i think they send 10 snapshots/sec and maintain 4 last snapshots and the game worked very well - is this also possible in the Netcode to change number of snapshots sent by server per sec?

@timjohansson

 

Is there already a fix for that?

I'm spawning rockets using predictive spawning which works pretty well.
Sometimes netcode spawns another rocket when it receives the first snapshot without deleting the old one.
The old one does get deleted once i spawn another one of the same Archetype.

 

I was able to fix my issue by replacing the if statement inside the DefaultyGhostSpawnSystem.cs at line 316 with

Code (CSharp):

1.          
2. if (m_NewGhosts.Length == 0 && m_DelayedSpawnQueue.Count == 0 && m_PredictedSpawnQueue.Count == 0 && m_SpawnRequestGroup.IsEmptyIgnoreFilter && m_PredictSpawnGhosts.Length == 0)
3.     return inputDeps;
4.  

The system was just not updating when it still had predictedSpawnGhosts pending which is why the rockets(predicted entities) did despawn once another one of the same type did get spawned.

 

I'm reaching the icomponent data limit, im currently capped of at 10 ghosts. are there any plans to lift this restriction? or is there some way of reusing ghost components (ie. have one projectile ghost and 20 variants of that one ghost for all the projectiles in the game)?


what should be and should not be a ghost? should a door be a ghost? i currently have 12 different door ghosts, seems like codesmell, but i need the door positions to be synced across all players, but i can't because of the size limit. what about pickups, should each pickup item be a ghost?

does a door in this case constantly use up bandwidth even though no one's interacting with it?

Edit: just scrolled up and saw it is getting fixed

 

Hello, @Stroustrup !
I would recommend you to differ between GhostPrefab as a template and actual visual representation. This will allow you to have an infinite number of door variants with only one DoorGhost. Also, it will save you from modifying all your doors if you decide to add more components later.
You can go further and move all your data to some kind of database/scriptobject whatever, and configure your ghost with that data after spawn.
So your workflow will be like:

Code (CSharp):

1. struct PickUpItem
2. {
3.     [GhostDefaultField]
4.     public int ItemId;
5. }
6.  
7. // Later in the code
8. var itemData = db.Get(pickUpItem.ItemId);
9. LoadVisual(itemData.Visual)
10. // etc.
11.  

 

Ok, i sent bug report. Let's wait the answer

 

Hello @timjohansson !
I've encountered an issue (at least from my perspective) and want to clarify if this behavior is intentional or it's a bug.

On the server I spawn a ghost and set some data:
var ghostEntity = commandBuffer.Instantiate(ghostPprefab);
commandBuffer.SetComponent(ghostEntity, new Component { ImportantData = value });

On the client I making some actions based on that ImportantData. When I run client and server in one process everything works fine and I'm receiving data from the server when the ghost is spawned. But when I run client and server in separate applications it looks like the ghost is spawned on the client without data from the first snapshot and receives it later. I thought that notification about newly spawned ghosts should come alongside with initial snapshot of data. Am I wrong?

Instatiation type of the ghost is "Interpolated"

Thank you!

 

Hi @timjohansson. Any plan to release new version of DOTS Netcode soon to compatible with latest Entities?

 

currently stuck on 2020.1 beta 14, neither netcode nor uitoolkit works on anything after that. hdrp 9 also broke for me

 

I use 2020.1.0f1 and it(netcode) works - though i (still) use netcode 0.1

 

but thats only compatible with entities 9 though?

 

entities 6 i think

 

While experimenting with the netcode, I struggle the most with custom type serialization for the ghost snapshot data.

For example in the Dots Physics package, there are many types (
PhysicsConstrainedBodyPair, PhysicsJoint etc.) which get picked up as fields in the ghost editor component, but don't get serialized to the snapshot data (and therefore not synchronized between client and server).

What would be the best way to add additional serialization for those types, so it won't get overwritten when code generation is triggered?

 

you need to add a ghost default field attribute to your components, note that very few components get serialized. i use the ascii characters inside of a nativestring 64 to sync player inventory because that's the longest ghost type.
alternatively to adding a ghost default field, you can manually enter the variable name inside your component by ticking the manual field list and regenerating code. but again, only thing that get's synced by default are byte, int, bool, nativestring64, float, float2, float3, float4 and that's all i think

 

I see a bunch of different netcode topics here in the DOTS forum. Wouldn't it be helpful to have a NetCode subforum like physics has?

 

Yeah many asked for subforum and admins never replied. Or at least someone could create NetCode discord channel and invite us that would be also nice(preferably devs) - solution not that good might be creating page with links to all NetCode threads or when ever someone posts NetCode thread she/he should start title with [NetCode]

 

has anyone got netcode to work with 2020.1?

 

Yes, but I have to make this change after generating the code: https://forum.unity.com/threads/har...pshots-of-child-entities.937298/#post-6124016

 

There's code for 2020.1 compatibility, ghost prediction despawning fix, and the Passing an argument of size '10568' laying around in the forum.

And those are just the posts that i'm aware of.

Even if you as the Netcode team don't like those changes and plan on doing something fancy in the future there are people who are looking for this stuff right now.

I think having a place where we could group all this stuff would benefit a lot.

 

+1 for topic specific sub forum for NetCode.

if components get added (or removed) at runtime to a ghost, how to best sync it between client and server?

does everything need to be handled with RPC’s or is there a better way?