NEW YORK – Black undies? Or white?

It was a choice that confronted writer-director Zack Snyder while making “Sucker Punch,” a mostly female action-fantasy starring Emily Browning as a gun-toting, sword-swinging killer deceptively named Babydoll. She dispatches zombies and robots with the kind of brutality that made Snyder’s mostly male “300″ a hit in 2007, but she also wears a thigh-high skirt that, as viewers will discover when “Sucker Punch” opens Friday, can be rather revealing.

The underwear question involved more than just aesthetics. As it turns out, Snyder wanted the color to downplay any titillation, not increase it.

“I did make a concession to say, ‘Let’s make her underwear black,”‘ Snyder says. “Otherwise I’m noticing it too much. If it was white, you see it. But those are the kinds of things we did, because I didn’t want the movie to be about that.”

It’s a small but important point that underscores the tricky nature of a movie whose sexual politics are as multi layered as its plot. A three-tiered narrative that unfolds in an insane asylum, a brothel and the escapist fantasies of its beleaguered heroine, “Sucker Punch” is a visual blend of pulp comics, steampunk and video-game violence, all shot in Snyder’s signature heightened style. One minute its female characters are invincible warriors, the next they’re chattel. And almost always, they are thoroughly rouged and suggestively dressed.

“It was difficult, at first, to convince the studio, not because it’s about all-female action characters but because it was so different,” says Snyder’s wife, Deborah, who helped produce the film for Warner Bros. “You usually pitch them a set of comps” — that is, clips of comparable movies — “but there were no comps for a movie like this. That was both exciting and scary.”

What has been done before is the revved-up mix of female-driven action and overt sexuality. The 1970s television show “Charlie’s Angels” was famous for strategically jiggling its heroines; Russ Meyer’s 1965 cult classic “Faster, Pussycat! Kill! Kill!” featured women with aggressive personalities and outsize bosoms. More recently, Angelina Jolie’s Lara Croft character often wore combat boots and little else.

“You have to recognize that we are making a genre movie, a movie that has elements of, say, Japanese anime,” says Carla Gugino, who plays the brothel’s mother hen, Madam Gorski. “In ’300,’ the men wore less clothing than we’re wearing! It is absolutely embracing that women can be sexy, strong, smart, all of those things.”

“Sucker Punch” features five young actresses cast somewhat against type. Browning (Babydoll) starred in the kids’ film “Lemony Snicket’s A Series of Unfortunate Events.” Abbie Cornish (Sweet Pea) played John Keats’ love interest in the costume drama “Bright Star.” Jamie Chung (Amber) recently had an eye-candy role in Adam Sandler’s “Grown Ups.” Jena Malone (Rocket) is known for indie films like “Bastard Out of Carolina.” And Vanessa Hudgens (Blondie) is a dimpled tween idol from Disney’s “High School Musical” franchise.

For “Sucker Punch,” however, they practiced martial arts, trained with assault rifles and worked out under Logan Hood, a former Navy SEAL who also wrangled Snyder’s actors on “300.” Malone, for one, piled 10 pounds of muscle on her 5-foot-6-inch frame and eventually pushed her rack dead-lift weight to 300 pounds.

“I get incredible work as an actor,” Malone says. “But no one ever says, ‘When I look at you I see someone who can kill 40 men with heavy artillery.’ Never had I had anyone instill that belief in me. It was incredible.”

The film goes so far as to exclude men entirely from the main cast. There are no “boyfriend” roles at all, and most of the male characters are villains, from Babydoll’s abusive stepfather to brothel owner Blue (Oscar Isaac, “Robin Hood”). Scott Glenn plays the Wise Man, a benevolent father figure who sends the women into battle; he is the film’s only “redemptive” male, according to Snyder.

At the same time, Snyder wanted his female characters to embrace certain traditional sexual archetypes — “the nurse, the French maid, the schoolgirl,” he says — and simultaneously take control of them. Such archetypes are common in movies with explicit sexual content, he notes, yet “Sucker Punch” seems destined to cause some hand-wringing even though it contains no sex scenes at all.

“The most dangerous place to go, I think, with female sexuality, is when people are conscious of their own sexuality and it becomes a tool,” Snyder says. “The power of it, when they’re aware of it — that’s dangerous. Society is not into that, for whatever reason. I thought we had a sexual revolution and everyone is cool with that. But apparently it’s still a hot-button issue.”