This is a test player.

‘Hard time dealing with reality?” asks the off-screen psychiatrist. “Always,” admits the title hero of “A Glimpse Inside the Mind of Charles Swan III.” Considering the actor playing him, you might be tempted to take that response with a horselaugh and a large dose of schadenfreude. But that would be a mistake. The actor/walking disaster known as Charlie Sheen gives a perfectly credible performance here. It’s the rest of the film that tries your patience.

Written and directed by Roman Coppola (son of Francis, brother of Sofia), “A Glimpse Inside the Mind of Charles Swan III” is exactly the kind of movie you’d imagine a scion of Hollywood royalty might make — sun-drenched, Art Deco, unambitious. It plays, sometimes engagingly, like the work of someone who has never had to work very hard.

Basing his hero loosely on Charles White III, a Los Angeles-based illustrator whose pioneering airbrush work graced countless album covers and movie posters in the ’70s, Coppola fashions a doodle of a character study that initially reels you in. Swan (Sheen) is a graphic-design rock star but his best years are behind him, and behind the ever-present shades he’s stuck in a creative rut. His latest California blonde, Ivana (Kathryn Winnick), has left him. He can’t come up with an album cover for his best friend, a superstar comedian named Kirby (Jason Schwartzman). His business manager (Aubrey Plaza of “Parks and Recreation”) and accountant (Bill Murray) can’t get him to stand still long enough to deliver the bad news.

Advertisement - Continue Reading Below

As the title implies, much of “Glimpse” takes place inside Swan’s head, in fantasy sequences that suggest “All That Jazz” stranded in Malibu. We get dance numbers set in graveyards, bossa nova musical performances (in Portuguese, no less), attacks by Swan’s ex-girlfriends dressed as Native Americans and Nazis. Our first glimpse of Murray is an absolute keeper: He turns up in the western sequence dressed as John Wayne in “True Grit.” But Coppola subsequently wastes this national treasure by giving Murray too little to do, just as he slowly kills his movie’s momentum with poky scenes illustrating Swan’s crisis of confidence.

If the character put me in mind of anyone, it’s the late singer-songwriter Harry Nilsson, another LA genius undone by indolence. But Sheen brings the right note of jaded panic to the role — we can assume he knows what it’s like to spin out in La-La Land — and he pitches Swan’s climactic speech to Ivana right on the line between nobility and maudlin self-pity. The movie’s too small to qualify as a comeback, but after Sheen’s public meltdown a while back, it’s nice to see his professional instincts are intact.

If only the movie itself amounted to much. Coppola’s a stylist, and his one previous effort as a dramatic feature film director, 2001’s “CQ,” is a lovely, eccentric riff on “Barbarella” and “8½.” He’s probably better known for co-writing a pair of Wes Anderson movies, “Darjeeling Limited” and last year’s “Moonrise Kingdom,” and already the cliché is that Coppola’s an Anderson without the rigor or emotional depth.

It’s a cliché because it’s true. Yet he has a real eye for resonant moments, like a slow-motion traveling shot of Swan and Ivana silently arguing their way through a car wash. That’s a truly LA image, and the movie is at its best when it captures the city’s airbrushed veneer and the dread that rankles beneath. For better and for worse — so far — Coppola’s one of those grown-up kids who can’t help but make home movies.