FILMMAKER James Cameron has topped himself.   The sci-fi blockbuster Avatar has passed the global box office gross of Titanic, the previous world-wide record holder at $ 1.843 billion, according to estimates by sources at 20th Century Fox, the studio behind Avatar. Both blockbusters were directed by Cameron.   Official numbers on Avatar's global gross are expected to be released Tuesday. Barring some unusual development, those figures will show that Avatar's global gross has topped that of Titanic.   According to box office figures from

Still from 1997 Oscar-winning film "Titanic" [Photo: Xinhua]   The 3-D version of 1997 Oscar-winning film "Titanic" directed by James Cameron is slated for release in 2012 to mark the 100th anniversary of the ship's sinking, according to media reports on Wednesday.   The RMS "Titanic", which set off on her maiden voyage from Southampton, England, April 10, 1912, sank on April 14, 1912 after hitting an iceberg.   In the film, the lone survivor of the accident, a 100-year-old woman named Rose DeWitt Bukator, narrates the