Trying to understand Unreal Engine 4 replication - unreal-engine4

I'm trying to understand how to call events between client and server. My goal for now is simple. I want to create anything that is interactable for 2 players.
Easiest thing I could think of was cube that is switching color when clicked. So I did create actor based blueprint, checked "Replicates" and AlwaysRelevant to be sure. PlayerController is also replicated and there is no pawn needed.
Color change blueprint:
SM is just static mesh if that is important. As far as I know client have no authority to call multicast events so I wanted to push it through server but it stops there. Called from server works as expected and color itself IS replicated to client, however client cannot change color himself.
What am I missing in this concept? I've watched like 5 videos about replication and I started to think there is something missing which is either obvious for everyone but me or their examples do not need things I do here.

As you've found out, a player's client can not directly call server RPCs on actors which the player does not own. Calls must be routed through that player's PlayerController. The server copy of the player's PlayerController can then call server methods on server-owned actors.
Another issue is that you seem to be using both RPCs and replicated properties for the same purpose. Unclear to me why changed is replicated since you're modifying it in a multicast event which normally runs on all the machines. This is a recipe for hard to find race condition bugs.
Replication in Unreal is definitely one of the harder concepts to get the hang of. The resource that helped me the most is this guide which while quite dated, is both comprehensive and to the point.

You can't have it in PlayerController, it's got to be in a Pawn, or if not, in PlayerState, or it won't get shared to other clients.

Related

Does a Level Sequence replicate over network?

I have created two level sequences, simple roll of an actor object. My goal is to be able to see those objects roll in all clients.
I do replicate the event on server and with multicast. I see that the blueprint goes up to the point to play the sequence but it is only triggered for the server.
Is it possible to trigger a sequence over network or I should use a different approach?
Found the solution, if anyone stumbles upon the same issue. I triggered the sequence through the player character and it worked just fine.

Triton inference server: Explicit model control

I need a little advice with deploying Triton inference server with explicit model control. From the looks of it, this mode gives the user the most control to which model goes live. But the problem I’m not able to solve is how to load models in case the server goes down in production which triggers a new instance to spawn up.
The only solution I can think of is to have a service poll the server at regular time intervals, constantly check if my live models are actually live and if not, load them. But this seems like quite a complicated process.
I would like to know how others have solved this problem.
Thanks in advance

Multiple or single NetworkManager in Unity

ok so I'm trying to get multiple matches going in an online multiplayer unity game and I need to know:
Is it better performance to manage all connections from a single NetworkManager or break up user connections into multiple ones? I ask with respect to performance. So will this be more costly for my server or the reverse?
danke sehr
ok so i thought about it a little more and since you can only have one active NetworkManager per scene (according to documentation ) I suppose I can't have multiple ones to break up connections as I was thinking.
My idea now is to use matchIds using Mirror but I'm stilling running into an issue. Collisions can still occur between GameObjects even though they have different matchIds.

How to synchronize a 1v1 realtime action online mini game?

What I'm trying to make
Hi, game development newbie here. The game I am trying to make is fairly simple. It's almost exactly like the old FC game "Ballon Fight" except that I'm trying to make it online where players can go through a match making to find opponents.
BalloonFight:
What I Read
I have read some articles, and found most of them lead to two approaches:
Put all game logic on the client, and the client sends player inputs to server on every frame update. The server acts like a dispatcher which only makes sure player A's input is received by both client A and B. My understanding is that if we see the client in this case as a pure function, and if the two players' inputs are received by each other, the game should produce same results on both clients. Thus synchronization is achieved.
Put all game logic on the server, and let the server do the calculations and send back results to both clients. In this case, clients only worry about displaying.
My Fears
Solution 1 sounded like a simpler one to me, but immediately I realized when network problem is put into account, it becomes incredibly complicated. Losing player A's connection for a few seconds means all the input is lost in that period. What I can guess is, to counter that, the server has to detect whether player A is lagged out and accumulate input from player B until player A is back then feed all the accumulated input to player A's client. Player A's client then need to do a fast forward to catch up. This sounds like there's huge amount of infra work on both client side and server side.
Solution 2 on the other hand looks very daunting to me, since for now I have only written some games on the client side.
My questions
in order to make a simple online game like this, what is the most beginner friendly way to synchronize game state?
if I were to use solution 1 stated above, is there any framework that provides such infra so that I don't have to handle network issues all by myself?
In advance, thank you game dev gurus.

Unity UNET How to change online scene in sync with clients

I'm using the old Unity 2017.3 UNET implementation in my game. Players connect to a server and are placed in a Lobby scene until the party leader selects another level to go to. The implementation is just a slightly modified version of the default NetworkLobbyManager.
The trouble started now that I've begun heavily testing the networking code by running a compiled build for a client and then using the editor as the server. Very frequently, the server running in the editor will run a great deal slower than the compiled client build. So when I use NetworkManager.ServerChangeScene the client will load the scene before the server, which will cause all NetworkIdentities on the client scene to be disabled (because they haven't been created on the server yet.)
It's a lot less likely to happen if the server is running a compiled build, because the server will almost always load the scene before any clients. But it does surface a bigger issue with Unity itself. That there's no guarantee that the server will be available when changing scenes.
Is there some other way of changing scenes in a networked game? Is there a way to guarantee that the server enters the scene before any clients? Or am I stuck just kind of hoping that the network remains stable between scene changes?
Well I thought about it more overnight and decided to look in other directions, because more investigation revealed that sometimes the Network Identities are still disabled when the server loads the scene first as well.
I was looking through the UNET source code and realized that the server should be accounting for situations where it loads the scene after the clients, although that code looks a little jank to me. This theory was backed up by the documentation I found that also says NetworkIdentities in the Scene on startup are treated as if they are spawned dynamically when the server starts.
Knowing those things now, I'm starting to think that I'm just dumb and messed some stuff up on my end. The object that was being disabled is a manager that enables and disables other NetworkIdentity objects. I'm pretty sure the main problem is that it's disabling a network identity on the client, that is still enabled on the server, which is causing the whole thing to go haywire.
In the future, I'm just going to try and stay away from enabling and disabling game objects on a networked basis and stick to putting relevant functionality behind a flag of my own so that I can "soft disable" an object without bugging out any incoming RPCs or SyncVar data.