Los Angeles ? Lots of movies have inspired video games, and lots of video games have sequels.

It’s extremely rare, however, for a game to be the official sequel to a movie — especially a film that’s 21 years old.

The appropriate subject for such a crossover is “Tron,” the 1982 cult film about a man who gets transformed into neon computer-code version of himself and has to fight his way back to reality.

The new PC game “Tron 2.0” picks up the story two decades later, when the previously empty world of computers is now crowded with spam, Internet traffic, security servers, firewalls, viruses and a population explosion of new and complex programs — all fighting for survival.

“Tron” writer-director Steven Lisberger, who wowed moviegoers in 1982 with his then-revolutionary, now-quaint computer animation, has wanted to make a film sequel for years. He still does.

But lately, he’s had to satisfy himself by serving as a consultant on the “Tron 2.0” game, developed by Monolith Productions and published by Walt Disney Co.’s Buena Vista Interactive.

“It’s sort of groundbreaking to approach it this way,” he said. “We’ve been kicking around scripts and concepts in the film division for quite some time now. The game division just blasted ahead and took the lead on this.”

If there is a third film installment in the “Tron” series — say, “Tron 3.0” — it depends on the success of the game.

Film director Steven Lisberger, who wrote and directed the original 1982 cyberspace movie Tron, stands before a Tron mural in Los Angeles. Lisberger consulted on an updated sequel to the movie and a new video game.

“There has been a regrouping and rethinking about how one does a film in conjunction with the game and, in a way, as a sequel to the game now,” Lisberger said.

Richard Taylor, who created many of the computer effects for “Tron,” also served as an adviser on “Tron 2.0.” He said a follow-up movie was years overdue.

“I run into people all the time who say they saw ‘Tron’ and that’s why they’re doing what they’re doing now,” he said of his work in video games.

“It tweaked a lot kids’ imaginations when they were 12 years old, and they’re still big fans.”

In the original, Jeff Bridges played a computer hacker named Flynn who gets digitized and finds that programs look just like their creators in neon suits.

The concept led to offshoot video games, and it’s influence can still be seen in movies like “Spy Kids 3-D: Game Over” and “The Matrix.”

Disney, sensing a “Tron” cult following, has rediscovered the movie. In addition to “2.0,” the company is releasing a series of action figures based on the story and a new comic book.