ON LOCATION : Sex, Drugs, Pick and Roll : Jim Carroll’s cult favorite ‘The Basketball Diaries’ is finally making it to the screen. It seems everyone wanted to star. Leonardo DiCaprio made the cut.

Matt Dillon wanted this movie. Anthony Michael Hall, Eric Stoltz, Ethan Hawke, Stephen Dorff--and River Phoenix, who may have wanted it too much. It’s perfect for any ambitious, talented young star who can play conflicted, charming and doomed.

The movie is “The Basketball Diaries” and the star is Leonardo DiCaprio.

It’s based on Jim Carroll’s 1978 book of the same name--a memoir of the 43-year-old poet and subculture hero’s days as a New York teen-age hoop prodigy and heroin addict. The book has been optioned many times, but either the project was wrong or the political climate was. Now with heroin, for better or worse, hot and basketball extremely cool, Island Pictures has lured DiCaprio and Mark Wahlberg (a.k.a. Marky Mark) and hired a first-time director to film Carroll’s visceral cautionary tale in and around the streets of New York City.

In the musty, echoing gym of Forest Hills High in Queens, Leo, as his friends know him, playing Carroll, is driving up court, Steadicam following alongside. He puts the basketball between his legs and passes to Wahlberg, who lifts the ball with both hands behind his head and scores a perfect layup. A bleacher full of teen-age extras goes wild. Wahlberg contorts his face into a victory scowl.

“Hooooo!” he exclaims.

DiCaprio smiles. They bump chests amicably.

A loud bzzzzzzz signals that the shot is over. “Beautiful,” says Scott Kalvert, the director. It’s the second day of shooting here. Doing a period movie would have cost too much, so everyone looks like ‘90s New York kids: black hair, white skin, baggy jeans. Forest Hills High is Kalvert’s alma mater. “I think they’ve still got my picture and prison number on the wall,” he jokes. Did he play basketball? “No. I did the drugs, though.”

It’s cold in Bruno Kirby’s trailer. The heat’s not working. A guy keeps trying to fix it. “No problem,” says the mild-mannered Kirby, who is discussing his character, Swifty, the perverted coach of Jim Carroll’s scrappy boy’s club team. The guy’s real name was Lefty, but all names except Jim Carroll’s have been changed for the movie to avoid lawsuits.

“NAMBLA,” Kirby says, referring to the National Man-Boy Love Assn. “Are you familiar with this organization? It’s quite scary, really.” Asked how he feels about playing a pedophile, Kirby demurs. “I don’t really play villains,” he explains. “I play people with problems.” Yes, well, Swifty’s “problem” is that he doesn’t just want to coach the pretty young men on his team, he wants to molest them.

This is just one of the squalid little details from Carroll’s bizarre youth. “The Basketball Diaries” appeared in book form in 1978, but he’d been publishing pieces of it in downtown New York literary magazines since the 1960s, when he was still a teen-ager.

When he wasn’t doing drugs or playing ball, he was hanging out around Greenwich Village and the St. Mark’s Place poetry scene. He made himself known to Allen Ginsberg and Gregory Corso, but preferred Randall Jarrell to the Beats. (He still publishes poetry, including a volume for Penguin called “Fear of Dreaming,” out this year.) In 1980, he branched out into rock, recording “Catholic Boy,” an album of spare rock ‘n’ roll and streetwise lyrics that included “People Who Died.” He was more of a punk than a hippie and for a while, Carroll was the punk movement’s Lou Reed.

For all these reasons, the book has always had a cult following. When MTV asked River Phoenix what he wanted to do after being nominated for an Oscar for “Running on Empty,” he pulled a battered paperback “Basketball Diaries” out of his pocket and said, “I want to play Jim Carroll.”

DiCaprio never met Phoenix, but saw him at a party in Los Angeles the night he died, a face in the crowd. “I said, ‘Was that River Phoenix?’ And then he was gone,” DiCaprio recalls. “It was kinda creepy.”

It’s warm in DiCaprio’s trailer. This is a low-budget movie: $4 million, according to producer Liz Heller. Maybe only the star gets heat. He’s sitting around in jeans and a hooded sweatshirt. He’s 5-foot-11 but doesn’t look it because he’s so skinny--a male Kate Moss. He’s an OK basketball player, not amazing. And he looks a little like the young Jim Carroll.

Between takes, he’s watching a pay-per-view event called something like “The Ultimate Guy Fight to the Death,” in which he-men from around the world battle in a no-rules Thunderdome until bones break or someone says “Uncle.”

DiCaprio does not want it mentioned that he was watching this festival of ultra-violence. Or that he was smoking. That would be bad example for his young fans. The teen-idol star of “This Boy’s Life,” “What’s Eating Gilbert Grape?” and next year’s “The Quick and the Dead” would rather keep his sins to himself. But he says he had no qualms about playing a kid junkie.

“I’m just gonna do the films that I’m gonna do,” he says. His voice is flat, affectless, Californian. A cold has made it raspier. He pops vitamin C tablets into his mouth like popcorn.

“You can’t always think of public perception, because if you get caught up in, ‘Oh, he’s a depressing actor. He just does dark films,’ you get locked into one thing,” he says. “You should just do everything, all types of different things.”

DiCaprio has been enjoying New York to the fullest since he got here in early spring. Tabloid gossip columns have reported numerous club sightings of him with Wahlberg and Kalvert. Asked if his research of the Jim Carroll experience has extended to experimentation with drugs (a persistent rumor), he says no, and his voice rises in astonishment at the question.

“Compared to this guy, I’m so clean, man, it’s ridiculous,” he says. “I swear--and I wouldn’t just say this for an interview--but I don’t do any of those drugs. It’s just acting for me. People said, ‘Why don’t you try it for the movie?’ and that’s just so lame, you know? You do drugs like that and it gives you an excuse to do them again.”

Despite the title, “The Basketball Diaries” isn’t really about basketball. It’s three years, age 13 to 16, in the life of an all-city athlete who at 6-feet-1 can dunk the ball backward and score 40 points in a game while doing almost every drug known to man. But with each successive diary entry, ball playing is replaced by drug playing. By the end of the book, all that’s left for Carroll’s keen intelligence and writer’s eye to observe is his own life going down the toilet.

“It’s a coming-of-age tale,” says Kalvert. “Like ‘Catcher in the Rye.’ ”

More like “The Catcher in the Rye” through the rheumy eyes of William Burroughs.

This is Kalvert’s first feature. His resume so far consists of music videos for Will Smith, Cyndi Lauper and Marky Mark and the Funky Bunch. It’s also the first produced screenplay for the writer, Bryan Goluboff. Kalvert is 30, Goluboff 27. Both are total Carroll groupies.

“I used to follow Jim around in the Village when I was 14 years old,” says Goluboff. Kalvert read the book at 18 and says he “lent it to everyone I knew.”

Sex and drugs are all over the “Diaries.” Carroll turns to prostitution to pay for his habit. Karen Akers, a New York cabaret singer, turned down a cameo in the film when told what the scene entailed: whips, razor blades, cruelty to cats. The worst has been toned down, say the producer and director. The last thing they want in a film starring teen idols is an NC-17 rating. So while moviegoers may not actually see DiCaprio stick the needle in his vein, they’ll see its evil effects.

“Toward the end of the movie, when you see some of the stuff that goes down--the prostitution, stealing from his mother (played by Lorraine Bracco)--it’s not pretty. People aren’t gonna say, ‘Wow, I want to do drugs.’ It’s sickening.”

The producers hired an ex-addict as a “drug consultant” to ensure authenticity. A genius at mimicry, DiCaprio can slip effortlessly into junkie mode.

“The voice: you go down an octave. Even when you raise your voice it’s like you got this frog in your throat,” he says, as if teaching an acting lesson. “It’s not necessarily being tired and it’s not necessarily like being drunk. It’s sort of like your body becomes jelly and all your bones and everything become completely relaxed. You just feel at peace. Supposedly. I don’t know. I’ve never done it. Right?” He laughs nervously.

A week later: another day of shooting, this time at St. Agnes Cathedral on East 12th Street in the Village. It’s a funeral for Jim’s friend Bobby.

The real Jim Carroll is sitting in the balcony, high above and removed from the action below. He looks like someone you’d see in a bus station. Long straight red hair, thinning at the temples, pulled back in a ponytail that hangs halfway down his back. Old jeans (he’s still lean). Old red-and-white leather Converse high tops-basketball shoes. Plaid shirt over a T-shirt, grunge-style. A baseball cap that says “NBA Jam Session.”

“When they first told me it was gonna be Leo, I didn’t know who he was,” Carroll says in his amused way. “If they’d said the kid from ‘Growing Pains,’ I would have known, because when I first saw that kid, I said, ‘This kid has a lot of presence.’ I said, ‘That kid is very pretty. He’s gonna do well.”

Who knew Jim Carroll watched “Growing Pains”?

When Carroll talks, he rarely looks you in the eye. He fixates on middle-distance objects and launches into long rambling bits of autobiography. His digressions seem like tangents, but they always come back to the point. His voice is nasal, New York-accented, with a slight lisp. He’s been clean since 1975, but he still talks like Dennis Hopper in “Apocalypse Now”--a hipster junkie rap with lots of exclamatory “wows” and “mans.” He also uses words like eschew and baroque --correctly--and has a memory like flypaper.

Carroll told DiCaprio about how they used to use eyedroppers instead of syringes to boot the heroin, about how he never got nauseous but would sometimes sneeze for nine hours straight, about how even when he was straight he used to “trance out” so much he was lost in thought that they called him “Dazey.”

Because he’s sick of being known as the “Basketball Diaries” guy for the last 20 years, the fact that they’re making this movie, he says, “just makes me want to work harder on something new.”

Mark Wahlberg is sitting on a stoop next to the cathedral. He’s in a geeky white shirt buttoned to the top and gray church pants. His hair is a goofy short bowl cut. The first thing he says, in his thick Boston street brogue, is “You wanna heah my impression of Jim?” Then he does it:

“The interesting thing with Mawky is he’s got such a name and I figure, Wow, I can’t have him in this movie! But gettin’ back to the first time I smoked a bag, Wow, I muthta been 13 years old. Leo’s great. Leo’s fabulous. He just plays bathketball a little differently.”

He’s got it down. Who knew Marky Mark had a sense of humor?

Wahlberg, who appeared earlier this summer in Penny Marshall’s “Renaissance Man,” read six times for the part of Herbie, Jim’s toughest buddy in “The Basketball Diaries.” “I felt the character in a lot of ways,” he says. “I wasn’t strung out on heroin but I was doing what I had to do, you know what I’m saying? It was more about money for us than getting high.”

Here’s the difference between Wahlberg and DiCaprio. Wahlberg, 24, has the wary humility of a guy who’s been spanked by stardom. DiCaprio, a cocky 19, acts like he thinks his star is always going to be on the rise.

DiCaprio wanders over from his trailer. He and Wahlberg talk trash at each other.

“What’s up?” says DiCaprio, “You sayin’ good things about me?

“No, whaddya kiddin’ me?” says Wahlberg.

“Can I have a cigarette?” says DiCaprio. Then he remembers there’s a reporter watching. “Oh yeah,” he says. “I don’t smoke.”

Rick Marin is a free - lance writer living in New York.