Melvin Van Peebles, who died Sept. 21 at 89, was not the inventor of Black cinema, but it’s no exaggeration to say that he smashed open the door to Black cinema as we know it. It’s a door that, until he came along, had been wedged tightly shut — by Hollywood and by mainstream American culture. There were a handful of Black actors who were stars, like Sidney Poitier and Lena Horne and Cicely Tyson, and a handful of films by Black filmmakers, but there was still a vast roster of things that Black artists working in the movies could and could not do. Van Peebles stood in front of his audience, holding that roster in hand, and burned it.

He was a novelist, a playwright, a recording artist, an actor, a director, a groundbreaker, a visionary: the filmmaker as one-man band. In key ways, he changed movie history, and if you believe in movies as much as I do, that really means that he changed history, period. He made it possible for a great many people to see themselves on the big screen in a new way, and therefore to believe in themselves in a new way. He created a mirror. His audience supplied the gaze.

“Sweet Sweetback’s Baadasssss Song,” the 1971 feature that accomplished all this, was a scrappy independent movie made for $500,000 (Van Peebles poured his savings of $70,000 into it), and it showed. Even now, it doesn’t look like other movies. It’s a bare-bones drama and a grainy dream; an extended music video; a series of tropes, motifs and references that come at you raw and unfiltered, ripped from the gut of the Black American experience. Van Peebles had made two previous features: “Watermelon Man” (1970), a relatively cutting-edge studio comedy starring Godfrey Cambridge as a bigoted white insurance salesman who wakes up one day to discover that he’s a Black man; and, three years before that, “The Story of a Three-Day Pass” (1967), a small drama, made and financed in France, that explored a soldier’s leave through the lens of a racism that’s all the more devastating for being so casual. Both films were fresh and new.

But “Sweetback” wasn’t just new. Unlike “Shaft” (released three months later), it was radical. Van Peebles trashed the rules, creating a new mythology and leaving a litany of smashed taboos — and, more than that, a sense of what the world might look like without them.

“Sweetback” has an outrageous opening that still resonates. A line of women — a makeshift matriarchy — stare, adoringly, at a boy eating his food. He eats like he’s starving, with patches on his scalp that suggest malnutrition. The music on the soundtrack is eerie sci-fi. The movie is telling us that this is square one: what poverty really looks like. And then, with spirituals playing in the background, we watch this mere boy lose his virginity — an incredibly transgressive image, but one that’s presented as an unholy liberation. This is Sweetback’s rite of passage, but the film has already cut ahead to him as an outlaw (played by Van Peebles, looking like a mustachioed hustler gunslinger), running and running and running.

As an adult, Sweetback performs in live sex shows, and he then gets taken downtown by two dastardly cops. When he beats them up and escapes, he winds up a fugitive. But this is no thriller. The images of Sweetback running in his black shirt, gold suede vest, and matching flared pants are really about what he’s running from. He has liberated himself from the Man, which means the System. The system of soul-threshing employment below your station; of not speaking your mind; of the jail you can be tossed into for next to nothing (or maybe nothing); of the cops who enforce it all.

Throughout the movie, in what amounts to a metaphysical sleight-of-hand trick, Van Peebles turns his lack of budget into an economy of means. The burning of a police car, through rapid-fire editing, becomes the burning of America. The wooden B-movie acting of the white actors playing cops becomes a form of kabuki: These policemen aren’t just mean and corrupt, they’re like aliens, foreign creatures with the empathy drilled out of them. And the film’s storytelling is as free as jazz — or, in fact, a then-unknown band named Earth, Wind & Fire, who lay down a funk ostinato topped by a snaky, blaring sax. “Sweetback” is an existential B-movie picaresque; you never know where it’s going next. What the EWF music tells you is that it’s all going to turn out okay. Sweetback flouts the System and wins.

The story of what happened to “Sweetback” is as enthralling as the tale the movie tells, and Melvin Van Peebles’ son, the actor-director Mario Van Peebles (who is, incidentally, the kid in that opening scene), made a fantastic movie about it. “Baadasssss!” (2003), which Mario wrote, directed and starred in, portraying his father, is a cracked movie-land biopic about how “Sweetback” got made and got presented to the world. Melvin Van Peebles knew his movie could strike a revolutionary chord, but he had to get it in front of audiences. The distribution network wasn’t interested. Sure, folks like John Cassavetes had made independent features (like “Shadows,” which really started the whole movement), but who saw them? Next to no one.

Van Peebles was able to open “Sweet Sweetback’s Baadasssss Song” at just two theaters, in Detroit and Atlanta, and the lines went around the block. The film’s title — what studio would have approved it? — already told the audience what they needed to hear: that this was going to be a movie torn from their experience. And it was. “Sweetback,” which received an X rating (it was marketed with the ad line “Rated X by an all-white jury”), went on to gross $15 million in America, the equivalent of $100 million today, and that was enough to light the torch of a revolution.

The studios began to greenlight Black films in its wake, and since those films, usually about the underworld, came to be known as “blaxploitation” (a horrible term, and one I admit I’ve used for years simply as a matter of convenience, but really it should be retired), they were often thought of in degraded terms. Some of them were grindhouse pulp. But not all. They were imperfect, but the stories they told were carved out of street life. And they reverberated. They were a formative influence on the world of hip-hop, and that would be true even if Van Peebles hadn’t recorded several albums in the late ’60s that are considered forerunners of rap.

There’s a perception at work in every frame of “Sweetback,” one that extends far beyond the movie — and, in a sense, back to half a century’s worth of movies. In 1971, that perception said: All the images of Black people you have ever seen in a Hollywood movie…those images were ultimately controlled by white people. Which is not to say that actors like Poitier and Tyson lacked creative agency; they were great artists. They presented truths. But they worked within imaginative frameworks that were not under Black control. “Sweetback” changed all that. As scrappy as it was, it was one of the first popular movies that was a pure expression of Black imagination and mythology. And that was its power. Van Peebles made it as if he were making the first movie. And so it felt every bit as unprecedented as it was. Van Peebles reinvented an art form, and he did it the old-fashioned way: by any means necessary.