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.
Related
I'm making a multiplayer game and for kind of all of it I need to have enemies and AI characters.
-for example 5-10 players in a match fighting a monster together. and the monster needs to be synced for all clients.
-or when there are not enough players online the server would add AI bots to the match so the player wouldn't get board.
I tried to make the AI and spawn it and give its authority to one of the players so the AI calculation doesn't cost the server.
Even though I couldn't have the server-side AI because Match Interest Management and that wasn't possible by that.
The problem starts when for example 2 players join a 4-player match and server adds 2 more bots everything works fine until when the match starts the first player which controls the AIs is fine but the other player gets freeze. I look for any infinite loops in my codes but I didn't find anything. I tried delaying spawns but still nothing.
The freezing happens when I use the dedicated server. in the editor and local network there is a very low chance it would happen.
if anyone knows Mirror Please help me if you think you can.
Thank You. Sorry if I didn't explained well.
Let's say I have an open world game that supports multiple players.
The game stores their positioning by X and Y in this world.
Also, whoever is playing the game can see a canvas of 11x11, where his player-self is represented on this screen, always centered.
The game world has 1000x1000 squares to walk using keys.
What I know is that:
I could emit events whenever a player walks,
check this event data at the server-side (to see if it is possible and the speed is correct/anti-cheating measures),
update the game state which contains all players and positioning,
re-emit this state from the server so every client would be able to render properly this new player.
The problem is, should I really update someone who isn't even being seen?
When everyone is walking around, moving items, earning levels, etc - those events are being emitted from the client, and that's okay, but thinking about the server-side, it will re-emit that for each update state, and, maybe that will be overloaded?
Also, sending the whole game state, even if it isn't being rendered, opens so many breaches to cheating that this made me think that there is another option.
I'm a beginner at Networking and Game Development, and that is being hard to get into my mind - so I decided to try and put it into a question. This way, maybe with someone reading what I'm thinking about, I might get some clarification. Perhaps I'm just thinking about it the wrong way.
Q: should I really update someone who isn't even being seen?
There is no need.
The normal way MMORPG games do in the server side is to cyclely process network packages and some other calculations like the connection of players like skill cast or something else.
The central of a server may look like below
void run()
{
while (true)
{
processNetwork();
processSkills();
processMoves();
...
}
}
The loop will run several times a second, like 20 frames a second is enough cause players can not feel the little frame, they think they move/play smoothly but the trueth is not.
For your question, player only need to see some little area, when he moves, the server will braodcast his postion to others in the area and the players in his area in the next frame.
And that is just the simpliest model, actual model will be more complicated and we will detach different functions of the game to different server, sucn as chat server, battle server, auction server and others.
What's the approach that should I use to develop an API that receives two moves and return a result (win/lose/draw)?
Scattegories game
Example:
Animal that starts with letter L
Player 1 - move: Lion
Player 2 - move: Lyon
thegame.com/api/v1/game/1/player/1/move/1
thegame.com/api/v1/game/1/player/2/move/1
How return the result to the players?
Should object player wait for the response or ask result?
What's the best way to develop an API with a callback?
Any other way to resolve this kind of problem?
Thanks.
Plurals are a bit more common, ie:
thegame.com/api/v1/games/1/players/1/moves/1
I think it's probably more logical for moves to be directly under the game, independent of players:
thegame.com/api/v1/games/1/moves/1
where each move has an associated player who made the move. This would make it easy to re-run all moves and understand the game history.
For players, their canonical URL would be independent of games
thegame.com/api/v1/players/1
You can still have a way to access all games for a player and all players for a game, if you like
thegame.com/api/v1/players/1/games
thegame.com/api/v1/games/1/players
Assuming this is a 2 (or more) player game with humans waiting on each other, you could probably make each client poll the game every few seconds. e.g. if a client has made the latest move, it starts polling the URL thegame.com/api/v1/games/1?moves_since=123456. This returns a list of all moves since the timestamp 123456. The timestamp could be the time the last move was made by this user. Once it returns a valid move, the client shows that to the user and waits for them to make their own move. If there are several players, the "game" resource could include a field like "nextMover" to indicate which player is next to make a move.
A more modern way would be to use something like Websockets so the client gets an immediate push from the server when changes occur. It's mostly a similar design but server immediately notifies all clients of updates instead of clients polling.
I'm trying to develop a TCG(trading card game) in Unity(I'm Unity newbie) and currently stuck on the architecture of the project and the card effects in particular. Coming from web development background for me all the logic and card effects should be on the server but going through some tutorials for Unity I think the logic should be on the client and I should use a simple room-based server to notify for player actions. Is that correct?
To summarize - where the game logic should be(e.g. card effects, rounds etc)? On the client or on the server?
I actually worked on one of the major TCG's out now for iOS/droid, so this is coming from experience. You definitely want all game logic and rules to be on the server. Do not trust your client to be the source of truth for any game outcomes etc. People will be able to hack that by tampering with the data sent back to the server. They don't have to decompile the game to do that, it can be done merely by sniffing the net traffic.
That said, you may end up with some duplicated logic on both client and server, only so that you can enforce game rules and display the outcomes without always hitting the server. However, your server is always the source of truth and the client is just there to accept input and display outcomes.
The general flow was the client would send a message requesting a new game to the server. The server would respond with the cards for each side and the opening move for the first player. Then the client would simply parse each move and display the outcome. On the cards objects we had methods for many of the actions, such as DrainHealth() and BuffAttack(). When called, these methods would trigger things like particle effects and sound fx attached to the card script.
Yeah the effects should be on the client, I assume your game will be turn based right? You might want to take a look at photon then:
https://doc.photonengine.com/en-us/realtime/current/getting-started/realtime-intro
They have a loot of good tutorials about their API and it's well documented :)
Hope that helps you,
good luck
I coded a bomberman application that uses a gamekit peer to peer connection. The problem is that after a while the game isn't in sync anymore.
I looked at the sample code for GKTanks and used their model. There is no client/server relation between peers so I didn't use one in my game. Both peers maintain a gamestate which they update based on received data.
I have a NSTimer that's used for running the gameloop at each frame. The NSTimers aren't in sync so sometimes the gamestates become different ex: players pick up a powerup at approximately the same time and they both get the powerup because it takes a while to send data.
I would appreciate any idea on making the app work. I'm thinking of rewriting the code to use client-server but I'm not sure if it's a good idea... yet
Thank you!
EDIT: I changed the code such that a random player is picked to be the host.
Every time a player places a bomb he asks the server where to place it. The server returns the players position(as seen on the server) and then tells the player where to place the bomb.
For powerups the server checks if a player picked up a powerup and if he did it sends a packet informing him.
Another problem has appeared now. The latency between devices is high(I'm using a bluetooth connection). It takes around 0.2 seconds to place a bomb after the client tapped the button to place it.
I'm sending all data reliably. Am I doing this right?
Well preferbly you want a host-client relationship where only the host can manipulate the game state, so in your case it would be:
Both players rush to the powerup.
Host picks it up first.
It gets registered and the host recieves the power-up.
Meanwhile player#2 also picks up the power-up, sends the action to the host.
The host informs player#2 that the power-up is already disappeared.
The thing with your situation you are bound to get desynchs from packet loss.
With host-client relationship that cannot happen, the only problem is the host always has an advantage that becomes greater when the latency increases between devices especially on smartphones.
In a game like bomberman it's perfectly plausible to send the entire gamestate each time something changes instead of the action that was performed, this is to ensure both devices are in sync.
To sum it up: both users have their gamestate but only the host can manipulate both.
what you should do:
one of the devices is host, another one is client
host process all the game states and makes decisions, then it sends whole gamestate to the client
client gets the gamestate and just draws everything based on it - it doesnt make any decisions (who picked bomb, did bomb exploded etc)
client just sends input to the host (pressed left,right, pause etc)
that's it. if you try to make decisions on both machines, you will run into big troubles trying to keep them in sync.