    // Valid weather modes.
    #define WEATHER_NONE		0
    #define WEATHER_CLOUDS		1
    #define WEATHER_RAIN		2
    #define WEATHER_SNOW		3
    #define WEATHER_FOG		4
    #define WEATHER_NIGHT		5

    // Sets a weather mode to be displayed via the V1RPG_Renderfunc()
    // function from v1_rpg.vc
    //
    // valid weather modes are:
    //
    // WEATHER_NONE, WEATHER_CLOUDS, ,
    // WEATHER_FOG, WEATHER_NIGHT
    //
    // WEATHER_RAIN and WEATHER_SNOW are not yet implemented.
    void SetWeather(int mode)

    // shakes the screen horizontally with a magnitude of x_intensity and
    // vertically with a magnitude of y_intensity for duration time
    void Earthquake( int x_intensity, int y_intensity, int duration )