On July 10, 2016, Unified Patents Inc. filed a petition for inter partes review, IPR2016-01374, against claims 1, 2, 3, 8, 18, 19, 20, 21, 25, 26, 27, and 28 of U.S. Patent 6,339,428, directed to a video graphics texture mapping. The patent is owned by an NPE called Advanced Silicon Technologies (AST) (http://adsiltech.com/), and is the third patent owned by AST that Unified has challenged.
A copy of the petition may be found on the PTAB portal.