透過範例在 Unity 和 NodeJS 上的遊戲中創建安全、快速的多人遊戲

mkdir multiplayer-game-server
cd multiplayer-game-server
npm init -y
npm install socket.io

// Create a simple socket IO server
const io = require('socket.io')(3000, {
    cors: {
        origin: '*'
    }
});

// Simple example of game states
let gameState = {};
let playerSpeedConfig = {
    maxX: 1,
    maxY: 1,
    maxZ: 1
};

// Work with new connection
io.on('connection', (socket) => {
    console.log('Player connected:', socket.id);

    // Initialize player state for socket ID
    gameState[socket.id] = { x: 0, y: 0, z: 0 };

    // work with simple player command for movement
    socket.on('playerMove', (data) => {
        const { id, dx, dy, dz } = parsePlayerMove(data);

        // Check Maximal Values
        if(dx > playerSpeedConfig.maxX) dx = playerSpeedConfig.maxX;
        if(dy > playerSpeedConfig.maxY) dx = playerSpeedConfig.maxY;
        if(dz > playerSpeedConfig.maxZ) dx = playerSpeedConfig.maxZ;

        // update game state for current player
        gameState[id].x += dx;
        gameState[id].y += dy;
        gameState[id].z += dz;

        // Send new state for all clients
        const updatedData = serializeGameState(gameState);
        io.emit('gameStateUpdate', updatedData);
    });

    // Work with unsafe data
    socket.on('dataupdate', (data) => {
        const { id, unsafe } = parsePlayerUnsafe(data);

        // update game state for current player
        gameState[id].unsafeValue += unsafe;

        // Send new state for all clients
        const updatedData = serializeGameState(gameState);
        io.emit('gameStateUpdate', updatedData);
    });

    // Work with player disconnection
    socket.on('disconnect', () => {
        console.log('Player disconnected:', socket.id);
        delete gameState[socket.id];
    });
});

// Simple Parse our binary data
function parsePlayerMove(buffer) {
    const id = buffer.toString('utf8', 0, 16); // Player ID (16 bit)
    const dx = buffer.readFloatLE(16);         // Delta X
    const dy = buffer.readFloatLE(20);         // Delta  Y
    const dz = buffer.readFloatLE(24);         // Delta  Z
    return { id, dx, dy, dz };
}

// Simple Parse of unsafe data
function parsePlayerUnsafe(buffer) {
    const id = buffer.toString('utf8', 0, 16); // Player ID (16 bit)
    const unsafe = buffer.readFloatLE(16);     // Unsafe float
    return { id, unsafe };
}

// Simple game state serialization for binary protocol
function serializeGameState(gameState) {
    const buffers = [];
    for (const [id, data] of Object.entries(gameState)) {
        // Player ID
        const idBuffer = Buffer.from(id, 'utf8');

        // Position (critical) Buffer
        const posBuffer = Buffer.alloc(12);
        posBuffer.writeFloatLE(data.x, 0);
        posBuffer.writeFloatLE(data.y, 4);
        posBuffer.writeFloatLE(data.z, 8);

        // Unsafe Data Buffer
        const unsafeBuffer = Buffer.alloc(4);
        unsafeBuffer.writeFloatLE(data.unsafeValue, 0);

        // Join all buffers
        buffers.push(Buffer.concat([idBuffer, posBuffer, unsafeBuffer]));
    }
    return Buffer.concat(buffers);
}

using UnityEngine;
using SocketIOClient;
using UniRx;
using System;
using System.Text;

// Basic Game Client Implementation
public class GameClient : MonoBehaviour
{
    // SocketIO Based Client
    private SocketIO client;

    // Our Player Reactive Position
    public ReactiveProperty<Vector3> playerPosition = new ReactiveProperty<Vector3>(Vector3.zero);

    // Client Initialization
    private void Start()
    {
        // Connect to our server
        client = new SocketIO("http://localhost:3000");

        // Add Client Events
        client.OnConnected += OnConnected;    // On Connected
        client.On("gameStateUpdate", OnGameStateUpdate); // On Game State Changed

        // Connect to Socket Async
        client.ConnectAsync();

        // Subscribe to our player position changed
        playerPosition.Subscribe(newPosition => {
            // Here you can interpolate your position instead
            // to get smooth movement at large ping
            transform.position = newPosition;
        });

        // Add Movement Commands
        Observable.EveryUpdate().Where(_ => Input.GetKey(KeyCode.W)).Subscribe(_ => ProcessInput(true));
        Observable.EveryUpdate().Where(_ => Input.GetKey(KeyCode.S)).Subscribe(_ => ProcessInput(false));
    }

    // On Player Connected
    private async void OnConnected(object sender, EventArgs e)
    {
        Debug.Log("Connected to server!");
    }

    // On Game State Update
    private void OnGameStateUpdate(SocketIOResponse response)
    {
        // Get our binary data
        byte[] data = response.GetValue<byte[]>();

        // Work with binary data
        int offset = 0;
        while (offset < data.Length)
        {
            // Get Player ID
            string playerId = Encoding.UTF8.GetString(data, offset, 16);
            offset += 16;

            // Get Player Position
            float x = BitConverter.ToSingle(data, offset);
            float y = BitConverter.ToSingle(data, offset + 4);
            float z = BitConverter.ToSingle(data, offset + 8);
            offset += 12;

            // Get Player unsafe variable
            float unsafeVariable = BitConverter.ToSingle(data, offset);

            // Check if it's our player position
            if (playerId == client.Id)
                playerPosition.Value = new Vector3(x, y, z);
            else
                UpdateOtherPlayerPosition(playerId, new Vector3(x, y, z), unsafeVariable);
        }
    }

    // Process player input
    private void ProcessInput(bool isForward){
        if (isForward)
            SendMoveData(new Vector3(0, 0, 1)); // Move Forward
        else
            SendMoveData(new Vector3(0, 0, -1)); // Move Backward
    }

    // Send Movement Data
    private async void SendMoveData(Vector3 delta)
    {
        byte[] data = new byte[28];
        Encoding.UTF8.GetBytes(client.Id).CopyTo(data, 0);
        BitConverter.GetBytes(delta.x).CopyTo(data, 16);
        BitConverter.GetBytes(delta.y).CopyTo(data, 20);
        BitConverter.GetBytes(delta.z).CopyTo(data, 24);

        await client.EmitAsync("playerMove", data);
    }

    // Send any unsafe data
    private async void SendUnsafeData(float unsafeData){
        byte[] data = new byte[20];
        Encoding.UTF8.GetBytes(client.Id).CopyTo(data, 0);
        BitConverter.GetBytes(unsafeData).CopyTo(data, 16);
        await client.EmitAsync("dataUpdate", data);
    }

    // Update Other players position
    private void UpdateOtherPlayerPosition(string playerId, Vector3 newPosition, float unsafeVariable)
    {
        // Here we can update other player positions and variables
    }

    // On Client Object Destroyed
    private void OnDestroy()
    {
        client.DisconnectAsync();
    }
}