Pong Clone with SDL3

An enhanced Pong clone for macOS, built with modern C++17 and the latest SDL3 / SDL3_ttf libraries. Features smooth ball physics, AI-controlled opponent with predictive trajectory tracking, adjustable difficulty levels, and on-screen scoring.

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🎮 Features

• Smooth Ball Physics — Subpixel movement using SDL_FRect for precise positioning
• AI Opponent — Predictive trajectory tracking with bounce simulation
• Adjustable Difficulty — Easy, Medium, and Hard modes with different AI behaviors
• Dynamic Gameplay — Ball speed increases on paddle hits, angle varies by hit position
• Score Display — Real-time score rendering with SDL3_ttf
• Classic Visuals — Dashed center line, clean black & white aesthetic

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🕹️ Controls

Key	Action
W / ↑	Move paddle up
S / ↓	Move paddle down
1	Set difficulty to Easy
2	Set difficulty to Medium
3	Set difficulty to Hard
ESC	Quit game

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📁 Project Structure

Pong/
├── main.cpp              # Entry point - creates and runs Game instance
├── src/
│   ├── Game.h            # Game class interface & Difficulty enum
│   ├── Game.cpp          # Full game implementation
│   ├── Ball.h            # Ball struct definition
│   └── Paddle.h          # Paddle struct definition
├── CMakeLists.txt        # CMake build configuration
├── conanfile.py          # Conan dependency manager config
├── conan_provider.cmake  # Conan CMake integration
└── README.md

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🏗️ Architecture

Classes & Structs

Ball (src/Ball.h)

struct Ball {
    SDL_FRect rect;  // Position (x, y) and size (w, h)
    float vx;        // Velocity in x direction (px/sec)
    float vy;        // Velocity in y direction (px/sec)
};

Paddle (src/Paddle.h)

struct Paddle {
    SDL_FRect rect;  // Position and size
    float speed;     // Movement speed (px/sec)
};

Difficulty Enum (src/Game.h)

enum class Difficulty { Easy, Medium, Hard };

Game Class (src/Game.h)

Main game manager handling initialization, game loop, rendering, and cleanup.

Method	Description
Init()	Initialize SDL3, TTF, window, renderer, and game objects
Run()	Main game loop - events, physics, AI, rendering
SetDifficulty()	Adjust AI paddle speed and behavior
ResetBall()	Reset ball to center with random direction
UpdateAI()	AI paddle movement with trajectory prediction
PredictBallImpactX()	Calculate where ball will intersect paddle plane
UpdateScoreTexture()	Render score text to texture

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🤖 AI System

The AI opponent uses predictive trajectory tracking rather than simply following the ball's current position.

How It Works

1. Trajectory Prediction — Calculates where the ball will be when it reaches the AI paddle's x-coordinate
2. Bounce Simulation — Uses modular arithmetic to simulate wall reflections:

   reflectedY = mod > h ? (2 * h - mod) : mod;

3. Difficulty Scaling — AI behavior varies by difficulty level:

Difficulty	AI Speed	Reaction	Accuracy
Easy	400 px/s	Waits until ball passes midfield	±20px random offset
Medium	640 px/s	Reacts at 30% field distance	±10px random offset
Hard	900 px/s	Immediate reaction	Perfect tracking

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⚡ Physics

Ball Movement

• Base Speed: 520 px/sec
• Max Speed: 1100 px/sec
• Speed Increase: 5% on each paddle hit
• Angle Range: ±25° initial launch angle

Paddle Deflection

The ball's outgoing angle depends on where it hits the paddle:

• Center hit → Shallow angle
• Edge hit → Steep angle (up to ~55°)

float impactDist = (ballCenter - paddleCenter);
ball->vy += impactDist * 5.0f;  // Angle adjustment factor

Collision Detection

Simple AABB (Axis-Aligned Bounding Box) collision:

if (bl.x < pl.x + pl.w && bl.x + bl.w > pl.x &&
    bl.y < pl.y + pl.h && bl.y + bl.h > pl.y && ball->vx < 0)

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🔧 Build Instructions

Prerequisites

Tool	Version	Installation
CMake	3.16+	cmake.org
Conan	2.x	pip install conan
C++17 Compiler	—	See platform-specific below

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🍎 macOS

Requirements

• Xcode Command Line Tools or full Xcode
• AppleClang (included with Xcode)

# Install Xcode CLI tools (if not already installed)
xcode-select --install

# Install Conan via Homebrew (recommended)
brew install conan

# Or via pip
pip3 install conan

Build & Run

# Clone the repository
git clone <repo-url>
cd Pong

# Install dependencies (first time only)
conan install . --build=missing

# Configure with CMake
cmake --preset conan-release

# Build
cmake --build --preset conan-release

# Run the game
./build/build/Release/Pong

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🪟 Windows

Requirements

• Visual Studio 2019/2022 with "Desktop development with C++" workload
• Or MinGW-w64 with GCC 8+

Option A: Visual Studio (Recommended)

# Install Conan (via pip or standalone installer)
pip install conan

# Clone and enter directory
git clone <repo-url>
cd Pong

# Detect default profile (first time only)
conan profile detect

# Install dependencies
conan install . --build=missing -s build_type=Release

# Configure with CMake (Visual Studio generator)
cmake --preset conan-default

# Build
cmake --build --preset conan-release --config Release

# Run the game
.\build\build\Release\Pong.exe

Option B: MinGW / MSYS2

# Install MSYS2 from https://www.msys2.org/
# Open MSYS2 MinGW64 terminal

# Install required packages
pacman -S mingw-w64-x86_64-cmake mingw-w64-x86_64-gcc

# Install Conan
pip install conan

# Configure Conan for MinGW
conan profile detect
# Edit ~/.conan2/profiles/default and set:
#   compiler=gcc
#   compiler.version=<your-version>

# Build steps same as macOS
conan install . --build=missing
cmake --preset conan-release
cmake --build --preset conan-release

# Run
./build/build/Release/Pong.exe

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🐧 Linux (Bonus)

# Ubuntu/Debian - install dependencies
sudo apt update
sudo apt install build-essential cmake libgl1-mesa-dev

# Install Conan
pip3 install conan

# Build (same as macOS)
conan install . --build=missing
cmake --preset conan-release
cmake --build --preset conan-release

# Run
./build/build/Release/Pong

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🛠️ IDE Integration

CLion

1. Open the project folder
2. CLion auto-detects CMake
3. Configure Conan plugin or run conan install . --build=missing in terminal
4. Select conan-release preset in CMake settings
5. Build & Run

Visual Studio Code

1. Install extensions: CMake Tools, C/C++
2. Run conan install . --build=missing in terminal
3. Select kit and preset via CMake Tools
4. Press F5 to build and run

Visual Studio

1. Run conan install . --build=missing in Developer PowerShell
2. Open folder (CMake project support)
3. Select conan-release configuration
4. Build with Ctrl+Shift+B

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📦 Dependencies

Managed via Conan:

Package	Version	Purpose
sdl	3.2.20	Windowing, rendering, input
sdl_ttf	3.2.2	TrueType font rendering

SDL3_ttf also brings in: Freetype, HarfBuzz, libpng, zlib, brotli

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🎯 Game Constants

Constant	Value	Description
Window Size	800×600	Default window dimensions
Ball Size	16×16 px	Square ball
Paddle Size	18×120 px	Paddle dimensions
Player Speed	720 px/sec	Left paddle movement speed
Font Size	48 px	Score text size

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📝 SDL3 Notes

This project uses SDL3 (not SDL2), which includes several API changes:

• Functions return bool instead of int for success/failure
• Event types use SDL_EVENT_* prefix (e.g., SDL_EVENT_QUIT)
• SDL_DestroySurface() replaces SDL_FreeSurface()
• SDL_RenderTexture() replaces SDL_RenderCopy()
• SDL_FRect used for subpixel precision rendering
• Must include <SDL3/SDL_main.h> separately

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📄 License

Open source - feel free to modify and extend!

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🙏 Acknowledgments

• SDL Wiki for comprehensive documentation
• Lazy Foo' Productions for SDL3 tutorials
• Hack Club for project inspiration