How are the three marks of existence experienced through Samadhi meditation?

Could dry vipassana & pure one-pointed samadhi type meditations just be different approaches to the same enlightenment? If one attains the fourth jhana with one pointed concentration does one experience anatta? What about anicca & dukkha? How is sunyata related to anatta? Is it really necessary to focus on non-consepts at some point in order for one pointed (ekaggata) concentration to lead to enlightenment? Are there scriptures that can help us understand this?