added fps; added time measurement of run loop; extra sleep commented out because of buggy update behaviour when used

src/Application.cpp

@@ -17,6 +17,10 @@ Application Application::app;
 void Application::run() {
     bool quit {false};
     while (!quit) {
+        // measure start time for this tick
+        auto start = SDL_GetTicks();
+
+        // handle events
         SDL_Event event;
         if (SDL_PollEvent(&event)) {
             switch (event.type) {
@@ -30,12 +34,29 @@ void Application::run() {
                     quit = handle_event(event);
             }
         }
+
+        // update windows
         for (const Window& window : Window::windows()) {
             window.update();
         }
+
+        // run any custom actions
         for (RunLoopAction action : _actions) {
             action();
         }
+
+        // measure end time for this tick
+        auto end = SDL_GetTicks();
+
+        // calculate how long this tick took, and how much is left
+        // if we want to maintain a steady fps
+        auto elapsed = end - start;
+        auto available = 1000 / _fps - elapsed;
+
+        // if there's any time left, sleep that much
+        if (available > 0) {
+            // SDL_Delay(available);
+        }
     }
 }
 

src/Application.hpp

@@ -36,11 +36,15 @@ namespace sc {
                 void add_run_loop_action(RunLoopAction action);
                 void remove_run_loop_action(RunLoopAction action);
 
+                int fps() const { return _fps; }
+                void fps(int fps) { _fps = fps; }
+
             private:
                 static Application app;
 
                 std::map<SDL_EventType, std::vector<EventHandler>> _event_handlers;
                 std::vector<RunLoopAction> _actions;
+                int _fps {60};
 
                 bool handle_event(const SDL_Event& event);
         };