Remember when you saw “The Truman Show” and thought, “Gee, this would have been better if instead of Jim Carrey it was a dog”? Well, the fellows at the Disney animation studios have taken your desires to heart and created “Bolt,” a jaunty action comedy about a Hollywood pooch who has lived his entire life thinking he actually has the mighty powers of the superdog he plays on TV.

His name is Bolt (voice of John Travolta), and he lives in a comfortable trailer on the Hollywood set where his show is filmed. But he doesn’t know it’s a set, or that he’s on a show, or that the show is filmed. The cameras are hidden, the stunt work carefully orchestrated so as to never require more than one take. It’s an elaborate (and, let’s be honest, cruel) ploy to wring better “performances” out of Bolt. If he truly believes his owner, Penny (Miley Cyrus), is in trouble every week, he’ll look extra-convincing to the viewing audience when he rescues her.

I question the wisdom of this system, not to mention the necessity of it. I don’t recall ever seeing a dog do something in a TV show and thinking, “Geez, I DID NOT buy that. That dog’s performance has failed to convince me.” As a storytelling device for the movie, it’s a needlessly elaborate way of setting up the meat of the plot, which is that Bolt winds up out in the real world and is crestfallen to discover he doesn’t actually have super powers. Surely there were simpler ways of getting to that.

Anyway, he winds up lost in New York City, still convinced that Penny is in actual danger. Believing that evil cats are to blame (“degenerate creatures of darkness,” he calls them), he takes a cynical alley cat named Mittens (Susie Essman) as a hostage and forces her to help him get back to L.A. Thus begins an “Incredible Journey”-style trek across the country, with Bolt and Mittens gradually becoming friends as she helps him learn how to be a regular dog. Can you imagine a puppy who never knew the joys of sticking one’s head out the window of a moving car? So sad.

Along the way they meet Rhino (Mark Walton), a hamster who basically steals the film from them. Rolling along in an plastic ball, Rhino is a devoted fanboy who watches Bolt’s TV show every week and is thrilled beyond measure to assist his hero in a real live caper. His earnest enthusiasm, Mittens’ wry cynicism, and Bolt’s ingrained heroism provide the kind of combo that buddy comedies always strive for but seldom achieve. “Bolt,” written and directed by a team of regular Disney crew members, finds good chuckles in the central trio, as well as in many of the peripheral characters, both on the Hollywood set (Penny’s agent is a great parody of wormy Tinseltown types) and in the animal world (including dialect-appropriate pigeons for every region of the country).

It’s even better when things get adventurous. The imaginatively exciting prologue, which is a sequence from the “Bolt” TV show, doesn’t just translate an action movie into cartoon form — it uses the animation medium to expand the scene’s potential. People, vehicles, and dogs can move much faster and more dangerously when you don’t have to worry about logistical things like stuntmen or camera placement. Putting the film in 3D only enhances the adrenaline effect, and there are several high-octane scenes like that sprinkled throughout the movie.

The story is shamelessly derivative, not just of “The Truman Show” and “The Incredible Journey” but of both “Toy Story” movies, not to mention the many films about people’s fantasy lives colliding with reality. In that regard, it’s less clever than many Disney cartoons have been. You won’t mind much, though, because it’s gentle and warm-hearted, and because you love dogs, and because you like to see them reunited with their owners.

B (1 hr., 36 min.; PG, mild action violence.)