As technology continues to evolve, game development has also progressed significantly from the days when Pong was a worldwide sensation. This progression has seen single-player games take a backseat to multiplayer games that connect players across the globe in real-time. However, a significant challenge that arises while creating multiplayer games is creating a functional multiplayer game server. This article seeks to provide an in-depth explanation on creating a multiplayer game server, breaking down the process into simple, manageable steps. Both experienced and novice game developers will find this guide useful in their game development journey.
How do online multiplayer games work?
Multiplayer games work by allowing multiple people to play the same game simultaneously on different devices. This is achieved through networking and synchronization, and players can either compete against each other or cooperate towards a common goal.
Offline multiplayer games are often played on a single device, while online multiplayer games require multiple devices connected to the internet. Online games typically use a server-client model where a central server hosts the game and all the players connect to it.
Communication between the devices can either be done through Transmission Communication Protocol (TCP) or User Datagram Protocol (UDP), which have different trade-offs in terms of speed and reliability. This communication involves the computers sending and receiving data through sockets using an IP address.
To ensure the games are synced and run smoothly, a game state is established detailing the current situation in the game. This state often needs to be updated frequently based on the actions of the players. To prevent the game from freezing during a delay in communication, systems use a buffer which provides a backup of the game state.
Moreover, to manage the delay when a player takes action such as moving a character or opening a door, client-side prediction is utilized. With client-side prediction, any changes a player makes to an object they own happens immediately and the updated state is sent to the server.
Finally, the implementation of these concepts and designs for multiplayer games can be achieved using networking frameworks like Unity’s Netcode, Photon, Mirror, and Fish-Net.
Why it’s hard to create an online multiplayer game?
Creating an online multiplayer game is a demanding task due to mainly two reasons – latency and the possibility of cheating.
Latency refers to the delay in the transfer of data from one device to another. This delay may not be significant when watching a video or browsing the internet, but for high-speed online multiplayer games where reaction time is crucial, it can be a real problem. This delay can affect the accuracy of the gameplay, where gamers may perceive moves or actions done by other players a fraction of a second later than when it was actually done.
Cheating is another major issue. In order to prevent fraud and ensure fair play, the server needs to perform all the calculations regarding the movements and actions of each player. However, this introduces another level of complexity and delay since every action needs to go through the server before it is finalized and visible to all players.
This is where client prediction comes in. In essence, both the client’s device and the server calculate the movement, aiming to reduce perceived latency on the player’s side. The client predicts the player’s action immediately after pressing a key, and once the server sends back its calculated position, the client compares it to its predicted position. If the server’s position and the client’s prediction don’t match, this triggers a correction of the player’s actual position.
Additionally, issues pertaining to game collisions can further complicate multiplayer design. For instance, two players might not be allowed to occupy the same space at the same time, depending on the game’s design. Dealing with game collision intricacies is another demanding task that makes designing an online multiplayer game difficult.
On top of these challenges, there’s the aspect of designing and implementing matchmaking systems, maintaining servers, dealing with network drops, and scaling the game for potentially millions of gamers playing simultaneously around the world. These requirements add further complexity to the task.
Understanding Multiplayer Game Servers
A multiplayer game server is primarily a host that connects multiple players to a single game, allowing them to play in real-time. Each player’s actions are transferred to the server, which sends back synchronized results to all connected players. There are two main types of multiplayer servers – local player hosted game servers and cloud/dedicated game servers.
Local Player Hosted Servers
In this model, a player’s computing resources are used to host the game, which their friends can join to play together. There are several benefits to this type of server, including giving players control over mods and game modifications, eliminating additional costs that come with dedicated servers, and easier scalability. However, the downside’s lie in less developer control and dependence on the host player’s connection, which could potentially disrupt the game.
Dedicated/Cloud Game Servers
On the other hand, dedicated or cloud servers host the game remotely. This server model provides more developer control, ensuring uniformity and fairness in gameplay. This model also allows persistent game states for “shared-world” games. Although it requires constant monitoring and incurs operating costs, offering a seamless gaming experience justifies this trade-off.
How to create a multiplayer game server?
Creating a multiplayer game server is a complex process, but it can greatly improve the player experience by allowing multiple people to enjoy the game simultaneously in a dedicated server environment. Here’s a step-by-step guide to creating a multiplayer game server.
Step 1: Set Up a Server
The first step is to set up a server that will host your game. There are many cloud server hosting options available such as Photon, Amazon Web Services, and Google Cloud. The choice depends on your budget, specific hosting needs, and familiarity with the platform. If you’re working with Photon, head to their website and create a free account, then set up a server.
Step 2: Link the Server to Your Game
After setting up your server, you will be given an Application ID or similar identifier, which you will use to connect your game to the server. This is typically done in the game’s code. Ensure to secure the App ID as it is sensitive information.
Step 3: Create a Loading Scene
Develop a user-friendly loading scene that your players will see while they’re connecting to the server. You should initiate a connection to the Photon Server during this loading scene. This can enhance the player’s experience of waiting while they establish a connection.
Step 4: Transition to Lobby
Once your player’s game client has successfully established a connection with your server, you’ll want to seamlessly transition them into the game’s lobby. The lobby is the central hub for players to meet, interact, and enter games together. It gives players options to create, join, or leave rooms.
Step 5: Create and Join Rooms
At this point, you have to implement capabilities that allow players to set up new game rooms or join existing ones. Every game room is basically a separate zone in the server—each game room can have its own game, separate from the rest. Remember to ensure that players can easily navigate this functionality and that they can smoothly join and leave rooms.
Step 6: Transfer to Game Scene
After players have successfully created or joined a room, it’s time to transition them to the actual game scene. This is the heart of your game, where the real action happens. The server must be programmed to maintain continuity and smooth transitions for players moving from the lobby into the game, ensuring no gameplay or data is lost in the process.
Step 7: Control the Player Characters
In the game scene, every gamer should be able to control his or her character independently of the others. You have to implement functions that enable players to interact within the game independently using their client, and confirm that all of these actions function correctly within the server environment.
Step 8: Sync all Movements
Arguably the most important step is ensuring all movements, actions, and game-related changes are synchronized across all game clients through the server. This is where a tool like Photon’s Transform View Classic Component becomes handy, as it helps to sync all in-game activities automatically. It is worth noting that depending on your game design, you might need to consider some additional aspects such as handling the logic for game-wide events and taking care of game-state persistence in case of connection failures.
Finally, make sure to beta-test your server with a group of gamers to ensure it works as intended. Recording and analyzing server logs are also essential parts of keeping your multiplayer game server healthy and functioning optimally. Creating a multiplayer game server is a complex job, but the rewards of a well-executed multiplayer experience can greatly enhance gamer enjoyment, and in turn, your game’s success.
Creating a multiplayer game server may seem daunting, especially to novice game developers. However, by breaking down this process into manageable steps, the task becomes less formidable. By creating a multiplayer server, developers open up a world of interconnected gaming for players, thereby adding significant value to their games. With a dedicated server, developers also maintain control over the game integrity, ensuring a fair and enjoyable gaming experience for all players. Although it requires continuous monitoring and potentially incurs operating costs, the payoff lies in the quality and seamless gameplay that can attract and retain players. With this guide, game developers are well-equipped to undertake the journey of creating their multiplayer game server and take their game from a single-player experience to a global, interactive platform.