Avengers reassemble and Top Gun flies back - Hollywood studios preview their new movies 10 hours ago Steven McIntosh, Paul Glynn and Ian Youngs, Culture reporters Getty Images Robert Downey Jr was unmasked as the villain Doctor Doom Some of the most hotly anticipated films of the next couple of years have been previewed at the annual gathering of the cinema industry, CinemaCon, in Las Vegas this week. The event gives fans and cinema owners a glimpse of the biggest movies coming down the tracks, with footage and trailers screened there - often before they're posted online. A-list stars and directors were on hand to give peeks at what to expect. From the Avengers to Ariana Grande to an AI Val Kilmer, here are some of the main films and what we learned. Doomsday is nigh Getty Images Director Joe Russo got in between Robert Downey Jr (left) and Chris Evans Disney showcased the first proper trailer for the long-awaited next Avengers film, Avengers: Doomsday, as the conference closed on Thursday.…