Yesterday the full cast was announced for Roland Emmerich‘s Stonewall as the movie started shooting. To coincide with that the director has been talking to EW about the difficulties of recreating the era that kicked off the gay rights fight.

“Nothing in New York looks like the ’60s anymore,” he says. “So we actually ended up with quite a big undertaking. We actually built part of Christopher Street and of the side of the Stonewall, just to be correct and how it really looked. Secondly, we do a lot of blue-screen. The movie ends with the first gay march, the gay liberation march in 1970, and that’s not possible anymore. So we do the whole scene with special effects, like blue-screen. We shot [that] in modern New York and turn it into 1969.”

So while it may be lower budget than Emmerich usual fare such as 2012 and Independence Day, it still sounds like he’s making plenty of use of VFX with the $20 million he does have to spend.

He also wants to point out that it is a fictionalised account of the events, “We do have some historic characters [in the movie], but the interesting thing about Stonewall is that actually the people we know about that lived during that riot, most of them are dead because they died in the AIDS crisis. Most of these kids, nobody knows about them much. We only know from witnesses, guys who fought in, in some respect, what is the day of revolution.”

As for why he decided to make the movie, “I was always naturally interested in the subject matter. Then, maybe two or three years ago, a couple of friends and I were kind of talking about marriage equality, and one of them said to me, ‘You know, Roland, you should make a gay movie.’ And I’m saying, ‘Well, nobody wants to see a gay movie from me.’ And then I kind of said, ‘Well, if it’s an important subject matter, then maybe they will.’ At the same time, I was involved with the L.A. Gay and Lesbian Center, and they told me that 40 percent of all homeless youth are gay, which is a disproportionate amount. That was like the bridge to today. It’s still going on. [Gay] kids get thrown out of their homes and become homeless, and [my movie] is like a story of one of these kids who gets involved in the whole Stonewall riots, because the riots were actually kind of done by the kids. A lot of them were homeless. They were hustlers, kids who had nothing to lose.”

Jeremy Irvine, Caleb Landry Jones, Jonathan Rhys Meyers, Ron Perlman, Joey King are all set to star in the movie, which should be out next year.