Need some extra stuff to make it work in mingw on Windows.

sfmldemo/main.cpp

@@ -1,5 +1,7 @@
 #include "imgui.h"
 #include "imgui-SFML.h"
+#define _USE_MATH_DEFINES
+#include <math.h>
 #include <fmt/core.h>
 #include <box2d/box2d.h>
 #include <SFML/Graphics/CircleShape.hpp>
@@ -73,7 +75,7 @@ int main() {
   sf::ContextSettings settings;
   settings.antialiasingLevel = 8;
 
-  sf::RenderWindow window(sf::VideoMode(720, 480), "Simple Game Demo", sf::Style::Default, settings);
+  sf::RenderWindow window(sf::VideoMode(1920, 1080), "Simple Game Demo", sf::Style::Default, settings);
 
   // window.setFramerateLimit(60);
   window.setVerticalSyncEnabled(true);