Code Notes made by Vaibhav Rathod

SFML (Simple and Fast Multimedia Library)

3 min read

Written by Vaibhav Rathod

History

  • Who: Created by Laurent Gomila.
  • Why: To provide a modern, object-oriented C++ alternative to SDL — with a cleaner API, built-in networking, and native C++ design (classes, RAII, no manual cleanup).
  • When: First released in 2007. SFML 2.x is the stable version. SFML 3.0 released in 2024 with C++17 and improved API.

Introduction

What is SFML?

  • A cross-platform C++ multimedia library organized into 5 modules: System, Window, Graphics, Audio, Network.
  • Designed for 2D game development with a clean, object-oriented API.
  • Website: sfml-dev.org

Advantages

  • Clean C++ OOP API — no manual resource management (RAII).
  • Built-in networking module (TCP/UDP sockets).
  • Easy sprite, texture, font, and sound management.
  • Cross-platform: Windows, Linux, macOS, iOS, Android.
  • Great for learning game development.

Disadvantages

  • 2D only (no built-in 3D — use OpenGL alongside).
  • Smaller community than SDL.
  • SFML 3 has breaking changes from SFML 2.

Installation & Setup

Linux (apt)

sudo apt install libsfml-dev

macOS (Homebrew)

brew install sfml

Windows (vcpkg)

vcpkg install sfml

CMake

find_package(SFML 2.6 COMPONENTS graphics audio network REQUIRED)
target_link_libraries(MyGame sfml-graphics sfml-audio sfml-network)

Core Concepts

Window & Game Loop

#include <SFML/Graphics.hpp>
 
int main() {
    sf::RenderWindow window(
        sf::VideoMode(800, 600),
        "My SFML Game",
        sf::Style::Default
    );
    window.setFramerateLimit(60);
 
    while (window.isOpen()) {
        sf::Event event;
        while (window.pollEvent(event)) {
            if (event.type == sf::Event::Closed)
                window.close();
            if (event.type == sf::Event::KeyPressed)
                if (event.key.code == sf::Keyboard::Escape)
                    window.close();
        }
 
        window.clear(sf::Color::Black);
        // draw here
        window.display();
    }
    return 0;
}

Shapes

// Circle
sf::CircleShape circle(50.f);  // radius 50
circle.setFillColor(sf::Color::Green);
circle.setOutlineColor(sf::Color::White);
circle.setOutlineThickness(2.f);
circle.setPosition(100.f, 100.f);
 
// Rectangle
sf::RectangleShape rect(sf::Vector2f(200.f, 100.f));
rect.setFillColor(sf::Color(100, 150, 250));
rect.setPosition(300.f, 200.f);
 
// Convex polygon
sf::ConvexShape triangle;
triangle.setPointCount(3);
triangle.setPoint(0, sf::Vector2f(0, 0));
triangle.setPoint(1, sf::Vector2f(100, 0));
triangle.setPoint(2, sf::Vector2f(50, 100));
triangle.setFillColor(sf::Color::Red);
 
window.draw(circle);
window.draw(rect);
window.draw(triangle);

Sprites & Textures

sf::Texture texture;
if (!texture.loadFromFile("player.png")) {
    return -1; // file not found
}
 
sf::Sprite sprite(texture);
sprite.setPosition(200.f, 150.f);
sprite.setScale(2.f, 2.f);       // 2x size
sprite.setRotation(45.f);         // degrees
sprite.setColor(sf::Color(255, 255, 255, 128)); // 50% transparent
 
// Sprite sheet — use texture rect
sprite.setTextureRect(sf::IntRect(0, 0, 64, 64)); // x, y, w, h
 
window.draw(sprite);

Input Handling

Keyboard

// Event-based (one-shot)
if (event.type == sf::Event::KeyPressed) {
    if (event.key.code == sf::Keyboard::Space)
        player.jump();
}
 
// Real-time (continuous)
if (sf::Keyboard::isKeyPressed(sf::Keyboard::Left))
    player.x -= speed * dt;
if (sf::Keyboard::isKeyPressed(sf::Keyboard::Right))
    player.x += speed * dt;

Mouse

// Mouse position
sf::Vector2i mousePos = sf::Mouse::getPosition(window);
 
// Event-based click
if (event.type == sf::Event::MouseButtonPressed) {
    if (event.mouseButton.button == sf::Mouse::Left) {
        int x = event.mouseButton.x;
        int y = event.mouseButton.y;
    }
}

Text & Fonts

sf::Font font;
font.loadFromFile("arial.ttf");
 
sf::Text text;
text.setFont(font);
text.setString("Score: 100");
text.setCharacterSize(24);
text.setFillColor(sf::Color::White);
text.setStyle(sf::Text::Bold | sf::Text::Underlined);
text.setPosition(10.f, 10.f);
 
window.draw(text);

Audio

#include <SFML/Audio.hpp>
 
// Sound effect (short, loaded into memory)
sf::SoundBuffer buffer;
buffer.loadFromFile("jump.wav");
sf::Sound sound(buffer);
sound.play();
sound.setVolume(80.f); // 0-100
 
// Music (streamed from disk — for long tracks)
sf::Music music;
music.openFromFile("background.ogg");
music.setLoop(true);
music.play();
music.setVolume(50.f);

Networking

#include <SFML/Network.hpp>
 
// TCP Client
sf::TcpSocket socket;
sf::Socket::Status status = socket.connect("localhost", 5000);
if (status == sf::Socket::Done) {
    std::string msg = "Hello Server";
    socket.send(msg.c_str(), msg.size());
}
 
// TCP Server
sf::TcpListener listener;
listener.listen(5000);
sf::TcpSocket client;
listener.accept(client);
 
char buffer[1024];
std::size_t received;
client.receive(buffer, sizeof(buffer), received);

Delta Time

sf::Clock clock;
 
while (window.isOpen()) {
    float dt = clock.restart().asSeconds();
 
    // Move at 200 pixels/second
    player.move(200.f * dt, 0.f);
}

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