Program.cs

using System;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Content;

using Networking;
using LiteNetLib;
using FontStashSharp;

class VindexGame : Game {
    [STAThread]
    static void Main(string[] args) {
        if (args.Length > 0) {
            Console.WriteLine($"Host address: {args[0]}");
            Globals.hostAddress = args[0];
        } else {
            Console.WriteLine("No arguments were passed.");
        }
        using VindexGame g = new();
        g.Run();
    }

    private VindexGame() {
        GraphicsDeviceManager gdm = new GraphicsDeviceManager(this);

        gdm.PreferredBackBufferWidth = 1280;
        gdm.PreferredBackBufferHeight = 720;
        gdm.IsFullScreen = false;
        gdm.SynchronizeWithVerticalRetrace = true;

        IsMouseVisible = true;


        Window.IsBorderlessEXT = false;

        Content.RootDirectory = "Content";
    }

    protected override void Initialize() {
        base.Initialize();
    }

    SpriteBatch? spriteBatch;
    protected override void LoadContent() {
        spriteBatch = new SpriteBatch(GraphicsDevice);

        GameAssets.Initialize(Content, GraphicsDevice, spriteBatch);
        Globals.window = Window;

        base.LoadContent();
    }

    protected override void UnloadContent() {
        spriteBatch?.Dispose();
        client?.Stop();
        server?.Stop();
        GameAssets.Unload();
        base.UnloadContent();
    }

    bool selected = false;

    Server? server;
    Client? client;

    protected override void Update(GameTime gameTime) {
        Globals.Update();
        Globals.gameTime = gameTime;
        if (selected && client?.netHandle != null) {
            server?.Update(gameTime);
            client.Update();
        }

        if (!selected) ChooseClient_Server();

        base.Update(gameTime);
    }

    public void ChooseClient_Server() {
        // Server & Client
        if (Globals.keyboardState.IsKeyDown(Keys.S)) {
            selected = true;
            server = new Server();
            server.Initialize();
            client = new Client();
        }
        // Client
        else if (Globals.keyboardState.IsKeyDown(Keys.C)) {
            selected = true;
            client = new Client();
        }
    }

    protected override void Draw(GameTime gameTime) {
        GraphicsDevice.Clear(selected ? Color.DarkCyan : Color.CornflowerBlue);

        Matrix pv_mat = Matrix.Identity;
        if (client != null && client.player.camera != null) {
            pv_mat = client.player.camera.getTransform();
        }

        if (client != null && client.netHandle.GetPeerHandle() != null) {
            spriteBatch?.Begin();

            DrawUI();
            DrawDebugText(spriteBatch);
            client.player.DrawUI(Vector2.Zero);

            spriteBatch?.End();
        }

        if (spriteBatch != null){
            spriteBatch.Begin(SpriteSortMode.Texture, BlendState.NonPremultiplied, SamplerState.PointClamp, DepthStencilState.None, RasterizerState.CullNone, null, pv_mat);
            DrawWorld();
            spriteBatch.End();
        }

        base.Draw(gameTime);
    }

    public void DrawUI() {
        float offset_x = 0f;
        float offset_x_delta = GameAssets.font.TextBounds("0", Vector2.Zero).X2 - GameAssets.font.TextBounds("0", Vector2.Zero).X;
        for (int i = 0; i < Server.MAX_PLAYERS; i++) {
            if (client.scores[i] >= 0)
                GameAssets.font.DrawText(GameAssets.spriteBatch, client.scores[i].ToString(), new Vector2(offset_x, Globals.window.ClientBounds.Height - 50), Server.PLAYER_COLORS[i]);
                offset_x += offset_x_delta * 3f;
        }
    }

    public void DrawWorld() {
        for(int i = 0; i < Server.MAX_PLAYERS; i++) {
            if (i == client?.player.id) {
                client.player.Draw(client.player.color);
            } else {
                client?.players[i]?.DrawUI(client.players[i].position - new Vector2(0, 27));
                client?.players[i]?.Draw(client.players[i].color);
            }
        }

        for (int i = 0; i < client?.bulletCount; i++) {
            if (client.bullets[i] != null) {
                if (client.bullets[i].safe_id == client.player.id)
                    client.bullets[i].Draw(Color.White);
                else
                    client.bullets[i].Draw(Color.Red);
            }
        }
    }

    public void DrawDebugText(SpriteBatch spriteBatch) {
        Bounds bounds = GameAssets.font.TextBounds("Hosting server", Vector2.Zero);
        float y_offset = 27.0f;
        if (server != null) {
            GameAssets.font.DrawText(spriteBatch, "Hosting server", new Vector2(0.0f, y_offset), Color.White);
            y_offset += bounds.Y2 - bounds.Y;
        }

        GameAssets.font.DrawText(spriteBatch, "Peer: " + client.netHandle.GetPeerHandle().GetID(), new Vector2(0.0f, y_offset), Color.White);
    }
}