A very simple SDL app framework

sdl_app.cpp

#include <cassert>
#include <cstdint>

#define _SDL_main_h
#include <SDL/SDL.h>

struct app_t {

  app_t() : _screen(nullptr), _active(false) {}

  virtual bool init(uint32_t w, uint32_t h) {
    const uint32_t mode = SDL_INIT_VIDEO;
    if (SDL_WasInit(mode)) {
      return false;
    }
    if (SDL_Init(mode)) {
      return false;
    }
    assert(!_screen);
    _screen = SDL_SetVideoMode(w, h, 32, 0);
    if (!_screen) {
      return false;
    }
    _active = true;
    return true;
  }

  virtual void on_event(const SDL_Event &event) {
    switch (event.type) {
    case SDL_QUIT:
      _active = false;
      break;
    }
  }

  virtual void tick() {
    SDL_Event event;
    while (SDL_PollEvent(&event)) {
      on_event(event);
    }
  }

  bool active() const { return _active; }

protected:
  SDL_Surface *_screen;
  bool _active;
};

struct my_app_t : public app_t {

  virtual void tick() {
    app_t::tick();
    SDL_FillRect(_screen, nullptr, 0x202020);
    SDL_Delay(1);
    SDL_Flip(_screen);
  }
};

int main(int argc, const char **args) {
  my_app_t app;
  if (!app.init(320, 240)) {
    return 1;
  }
  while (app.active()) {
    app.tick();
  }
  return 0;
}