Created attachment 3843 [details]
Sample log output showing frame time vs frequency of mouse movement polling

Note: My Mac OS X version is 10.14 (it wasn't listed in the OS selection)

I'm using SDL to process input in a small game I'm working on. I've just got some drag-and-drop stuff working in a menu but I noticed something super weird: as the game runs, the drag-and-drop gets more stuttery and jumpy over time. My frame rate is roughly 60 FPS, but when the game loop starts the mouse events are only firing every 2 frames or so and then become less frequent over just a few seconds. I see lots of complaints online about SDL_PollEvent being slow, but the solves for those cases are exactly what I'm already doing: running SDL_PollEvent in a loop. What am I doing wrong here?

I'm using SDL2 2.0.9 and the problem exists on 2.0.8 as well.

This is the event processing loop from the top of my game loop:

  void poll_events() {
    SDL_Event event;
    while (SDL_PollEvent(&event)) {
      switch (event.type) {
        case SDL_WINDOWEVENT:
          handle_window_event(event.window);
          break;
        case SDL_MOUSEMOTION:
          handle_mouse_motion_event(event.motion);
          break;
        case SDL_MOUSEBUTTONDOWN:
        case SDL_MOUSEBUTTONUP:
          handle_mouse_button_event(event.button);
          break;
        case SDL_MOUSEWHEEL:
          handle_mouse_wheel_event(event.wheel);
          break;
        case SDL_KEYDOWN:
        case SDL_KEYUP:
          handle_key_event(event.key);
      }
    }
  }

I've attached a sample of my log output showing frame time vs frequency of mouse movement events.