A zombie? No, it’s Tom Hanks from The Polar Express.

Warner Bros.

With a big assist from Silicon Valley technology, a movie superstar like Angelina Jolie could keep starring as Lara Croft in Tomb Raider sequels — forever.

Aided by increasingly powerful microprocessors and incredibly sophisticated software, moviemakers and video-game developers are getting closer to achieving the holy grail of animation: creating computer-generated actors that are visually indistinguishable from real people. Consider it Hollywood’s most special effect.

Experts say that could bring revolutionary changes for film lovers and game players. Stars could keep playing iconic roles even as they aged past the point of believability, like Jolie as Croft or Daniel Radcliffe as Harry Potter. At the same time, video games could look more realistic — in fact, more like movies themselves.

“Basically anything a person can dream up, we’ll be able to create,” said Mark Starkenburg, chief executive of Santa Monica-based Image Metrics, which recently made a very lifelike computer-generated video of a soap-opera actress using new chips from Advanced Micro Devices of Sunnyvale, Calif.

The video isn’t perfect, however, and experts say chips and animation software need to get much better to be able to produce computer-generated actors that look identical to the original.

But “we may be getting to the tipping point,” said Rick Bergman, general manager of AMD’s graphics products group. “With what we’re starting to deliver with our chips, the computing power is getting real close.”

Over the past three decades, computer-produced graphics have created stunning visual effects in films such as Alien, Total Recall, Jurassic Park, Titanic and Lord of the Rings. Lately, increasing numbers — including all the new Disney-Pixar collaborations, such as Bolt and the upcoming Monsters vs. Aliens — are shown in 3-D.

But while animators have been able to make very realistic-looking representations of buildings, trees and other objects, the complexity of the human face and its subtle emotions have proven too difficult to replicate.

For now, producers have generally avoided even trying to make digital characters that look like actual people. And when they have, they’ve often blundered into what those in the industry call the “uncanny valley.” That’s where animated faces seem so devoid of normal human expressiveness they appear zombielike, a problem critics claim especially cropped up in the 2004 movie Polar Express that starred a synthetic Tom Hanks.

But in creating its video of the TV soap-opera actress — Emily O’Brien, who has appeared in The Young and the Restless — Image Metrics found another solution. It used a device developed by the University of Southern California’s Institute for Creative Technologies, which can digitally capture enormous amounts of visual detail about human actors, including their faces.

Computer generation gives film producers enormous creative flexibility. Besides allowing them to change actors’ appearance — by digitally exaggerating their movements or facial expressions, for example — it also makes it easy to create elaborate animated environments, which can be a lot cheaper than having to fly an entire movie crew to exotic locations.

Moreover, being able to create digital characters that are indistinguishable from real people would enable performers who have grown older, or have even died, to continue appearing in movies, said Jules Urbach, who has licensed USC’s technology to use in his Burbank animation business, LightStage.

Urbach said an actor in his 30s — whom he declined to identify — recently asked him to capture the man’s image with LightStage so the actor can star in future animated films without ever looking a day older than he does now.

If needed, Urbach added, the actor’s words could be digitally generated years from now through computerized voice reconstruction, a technology that also is rapidly advancing.

While all this might let actors collect film royalties well past their prime, some critics have decried giving animators so much creative control. Yet Mark Friedlander, director of new media for the Screen Actors Guild, said his members shouldn’t panic yet over what he called “blurring the line between the real and the synthetic.”

“It certainly is something we’re beginning to watch,” he said. But he added, “I don’t really see technology in any way replacing performers. I see it enhancing the possibility of storytelling.”