Gene Maddaus Senior Media Writer Prince Royal, an actor in Los Angeles, was working as an extra on “The Flash” when he was directed to a tractor trailer to “take pictures.” Inside were hundreds of cameras. He stood with his arms up as the operators took a 3-D scan, which he was told would be used for continuity and special effects. “We were told if we didn’t do it, we’d be sent home without pay,” he said.