Writing In The Attic Rockwell What Is The True Story For Flowers In The Attic?

What is the true story for flowers in the attic? - writing in the attic rockwell

I read the novel Flowers in the Attic, and saw the movie. I hear that is based on a true story. I wonder what the real story and what happened? Virginia was written from the experience? I am well known for his novels, have a model of incest