It’s not as easy as it used to be to get a movie made. But that hasn’t slowed writer-director Richard Linklater, whose latest film, “Bernie,” opened in limited release April 27 to strong box office.

“I have three or four balls in the air right now – and I’m usually writing two or three scripts all the time,” Linklater, a still-boyish 51, says, sitting in a Manhattan hotel. “I have a huge backlog of projects – probably eight or nine that are viable. I used to be able to dig in my heels about what I wanted to do next. Now, it’s about whichever of the three or four projects I have ready to go can get financing.”

“Bernie,” based on a true-crime story from a small Texas town, is a film Linklater knew he wanted to make when he first read the Texas Monthly story about the case in 1998. He attended the trial of Bernhardt Tiede, the mild-mannered assistant funeral director charged with murdering Marjorie Nugent, the rich widow who was his companion, and even visited Tiede in jail after he was convicted.

“But the movie didn’t happen because, in 2000, when I wrote it, no one popped into my mind in terms of casting,” Linklater says, “so it wasn’t on my fast track.”

After Linklater made “The School of Rock” in 2003, he mentioned the script to the film’s star, Jack Black: “Having worked with Jack, I thought there was an element in Jack that would dial into Bernie, that Jack could relate to,” Linklater says. “Once he and Shirley (MacLaine) and Matthew (McConaughey) signed on, we had enough steam to get it made.”

The film tells a true story and was shot in Carthage, Texas, the small town where the real events occurred. It even incorporates real residents of the town, talking to the camera about Bernie (though most of their remarks are scripted).

“This story reflected a lot of what my own small-town life was,” Linklater says. “I think about my mom and her friends. There’s always a lot of personality behind their opinions. So that gossiping group is like a Greek chorus, at the conceptual-storytelling level. With Bernie gone and Mrs. Nugent dead, these people were all that was left to talk about their take on the story and the characters. And believe me – in Carthage, everybody has an opinion about whether Bernie killed her or not.” (In fact, Tiede confessed to the murder and is serving a life sentence.)

Linklater met Tiede after corresponding with him in prison: “Really, the only people who write letters anymore are people in prison,” he says. “Bernie wrote these beautiful, flowing letters. When I met him, he wasn’t some charming psychopath. He’s a genuinely sweet guy who did one bad thing. And now he’s a model prisoner, doing all these positive things in prison.”

Linklater burst on to the scene with 1991’s “Slacker,” and has directed more than a dozen features since then. His credits run the gamut from low-budget indies (“Tape,” “Waking Life”) to studio comedies (“School of Rock,” “Bad News Bears”). He’s learned to work the system so that he’s always ready with a script and a cast, should the money suddenly show up.

“Right now, I’ve got a few things that are right on the cusp of happening,” he says. “We just have to see how the planets line up. I wish I could say I was already in post-production on my next film that would come out in the fall. But that’s not the case.

“It used to be that the industry would say, ‘OK, we can scrounge together the money to get this made.’ Now, when you say what you want to do next, the industry says, ‘We don’t care.’

“I got pretty lucky. I got a lot of films made that wouldn’t have been made without the independent film boom of the ’90s. I’d hate to be starting out now. It’s a tough time to get backing, to make a cultural impact, to even get your film shown in theaters. I’m not complaining; you do your best within the system.”