Open window, center camera, and draw circle

src/main.cpp

 #include <cstdio>
 
-int main() {
-	std::puts("Hello cube!\n");
+#include <SFML/Audio.hpp>
+#include <SFML/Graphics.hpp>
+
+int main()
+{
+	// # Create the main window and camera
+	sf::RenderWindow window(sf::VideoMode(800, 600), "Double trouble");
+	window.setFramerateLimit(90);
+	sf::View camera(sf::FloatRect(0, 0, 800, 600));
+	camera.setCenter(0, 0);
+	window.setView(camera);
+
+	// # Create things
+	sf::CircleShape circle;
+	circle.setPosition(0, 0);
+	circle.setRadius(10);
+	circle.setFillColor(sf::Color::Red);
+
+	while (window.isOpen())
+	{
+		// # Process events
+		sf::Event event;
+		while (window.pollEvent(event))
+		{
+			// ## Close window on exit
+			if (event.type == sf::Event::Closed ||
+				event.type == sf::Event::KeyPressed &&
+					event.key.code == sf::Keyboard::Escape)
+			{
+				window.close();
+			}
+		}
+
+		// # Render video
+		window.clear();
+		window.draw(circle);
+		window.display();
+	}
 	return 0;
 }
-