Sam Rockwell is developing a film about the legendary boxer Marvin Hagler. The 55-year-old actor and Mark Berger’s Play Hooky production company have secured the rights to Dave Wedge’s upcoming book about the late fighter titled ‘Blood and Hate: The Untold Story of Marvelous Marvin Hagler’s Battle for Glory’ after a competitive bidding war. The book follows Hagler – an underdog from Newark who moves to Brockton, Massachusetts and begins training under the eye of brothers Goody and Pat Petronelli. Hagler developed into a leading middleweight contender and earned a world title shot against Briti…