PONG — MonoGame OOP Teaching Project

A classic two-player PONG game built with MonoGame DesktopGL on .NET 10, designed as a teaching example for object-oriented programming and event-driven architecture in C#.

Gameplay

Player	Up	Down
Player 1 (left)	W	S
Player 2 (right)	↑	↓

Press Enter to start and to serve. Press Escape to quit.

Project structure

Game1.csproj
Program.cs              ← Entry point, creates and runs the game
Types/
  Game1.cs              ← Orchestrator: creates objects, wires events, calls Update/Draw
  Ball.cs               ← Ball physics, collision detection, fires events
  Paddle.cs             ← Paddle input handling and movement
  ScoreBoard.cs         ← Score tracking, fires ScoreChanged
  GameState.cs          ← Enum: Welcome | WaitingToServe | Playing
  ScoredEventArgs.cs    ← EventArgs for Ball.Scored
  PaddleHitEventArgs.cs ← EventArgs for Ball.PaddleHit
  ScoreChangedEventArgs.cs ← EventArgs for ScoreBoard.ScoreChanged
Content/
  Font.spritefont       ← Bitmap font (Arial 32pt) built by content pipeline
  Content.mgcb          ← MonoGame content pipeline build file

OOP concepts demonstrated

Concept	Where
Encapsulation	Each class owns its data — only exposes what others need
Single Responsibility	Ball handles physics, Paddle handles input, ScoreBoard tracks points
Events & Delegates	Objects communicate via events — no tight coupling
EventArgs subclasses	Strongly typed event data (ScoredEventArgs, PaddleHitEventArgs, ScoreChangedEventArgs)
Dependency Injection	Paddle receives its keys via constructor
Nullable reference types	Enabled project-wide — fields are null! until initialised in Initialize()

Event flow

Ball ──────→ Scored          → Game1.OnBallScored  → ScoreBoard.AddPoint()
        ──→ PaddleHit        → Game1.OnPaddleHit   → (extension point: sound)
        ──→ WallHit          → Game1.OnWallHit      → (extension point: sound)
ScoreBoard → ScoreChanged    → Game1.OnScoreChanged → (extension point: win condition)

Getting started

Prerequisites: .NET 10 SDK

# Run in development
dotnet run

# Debug in VS Code
# Press F5 — uses .vscode/launch.json

Publishing

# Builds self-contained executables for Windows, Linux, and macOS
powershell -ExecutionPolicy Bypass -File .\publish.ps1

Output:

publish\win-x64\Game1.exe        Windows x64
publish\linux-x64\Game1          Linux x64
publish\osx-x64\Game1            macOS Intel
publish\osx-arm64\Game1          macOS Apple Silicon

AI assistance (GitHub Copilot)

This project includes a custom Copilot agent and skills to help work with MonoGame:

	Name	Use
🤖 Agent	monogame-dev	MonoGame API help, game loop questions, content pipeline
🛠 Skill	/add-game-object	Add a new entity following the OOP/event pattern
🛠 Skill	/add-screen	Add a new game screen (Game Over, Pause, etc.)
🛠 Skill	/add-sound-effect	Add audio via the content pipeline
🛠 Skill	/debug-collision	Draw hitboxes to visualise collision detection