mainloop SDL

void Game::loop() {
    // mainloop inspired on http://bit.ly/wcSotJ
    int start = SDL_GetTicks();
    double frame = 0;
    int fps = 15;
    SDL_Delay(fps);
    while (running) {
        frame++;
        double delta = (SDL_GetTicks() - start) / frame;
        printf("%f\n", delta);
        SDL_PollEvent(&event);
        step(delta);
        draw();
        if (event.type == SDL_QUIT //
        || (event.type == SDL_KEYDOWN && event.key.keysym.scancode == 9)) // ESC
            running = 0;
        SDL_Delay(fps);
    }
}