Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Minkowski Portal Refinement collision detection algorithm is a technique for determining whether two convex shapes overlap. The algorithm was created by Gary Snethen in 2006 and was first published in Game Programming Gems 7. The algorithm was used in Tomb Raider: Underworld and other games created by Crystal Dynamics and its sister studios within Eidos Interactive. MPR, like its cousin GJK, relies on shapes that are defined using support mappings.