function ease_inout_circ(arg0, arg1, arg2, arg3)
{
    arg0 /= (arg3 * 0.5);
    if (arg0 < 1)
        return (arg2 * 0.5 * (1 - sqrt(1 - (arg0 * arg0)))) + arg1;
    arg0 -= 2;
    return (arg2 * 0.5 * (sqrt(1 - (arg0 * arg0)) + 1)) + arg1;
}