Projects such as “Ed Wood” and “American Movie” have proven it’s possible to create a great film about the making of a terrible one.

And make no mistake about it, 1971’s “Sweet Sweetback’s Baad Asssss Song” is a mess. For those who have excised it from their memory, it’s the tale of a male prostitute (writer-director Melvin Van Peebles) who saves a Black Panther member from racist cops then spends the rest of the time running from “the Man.”

Choppy, trippy and X-rated, the flick was deemed unreleasable at the time. Yet it’s undeniably potent anti-establishment themes caught on with the urban crowd.

Shot for just $150,000, the picture went on to make $15 million and helped usher in the era of the “blaxploitation” film. (The term is a real misnomer, because for once black filmmakers were finding their own voice INSTEAD of being exploited.)

“Baadasssss!” chronicles the fascinating tale behind the making of this cultural landmark.

Mario Van Peebles — the son of Melvin — writes, directs and portrays his father. To say he nails the role is an understatement. He embodies not just the physicality of the man but the entire concept of what his dad went through to make his signature film. (The then-13-year-old Mario actually had two roles in “Sweetback’s” and experienced the day-to-day filming at his pop’s side.)

“Times were changing. The Panthers knew it. Students knew it. Hollywood was ignoring it,” Peebles narrates during the intro.

Set in 1970, the filmmaker has just finished his first studio effort, “Watermelon Man,” and is trying to use this clout to make a movie for black audiences. He envisions a script in which a black hero fights against white cops and wins — and doesn’t die at the end.

Instead of big-name actors, he “wants the picture to star the community. All the faces that Norman Rockwell never painted.”

Mario Van Peebles, right, explains his concept for an anti-establishment film to his agent (Saul Rubinek) in Baadasssss!

Peebles depicts his father as a kind of mad genius — part tortured artist, part cigar-chomping drill sergeant. Once things begin to turn against him in terms of financing, he becomes obsessed with being able to finish the project using any means necessary.

The most intriguing portions of this drama involve tales of how the elder Peebles circumvents the system in order to keep the camera rolling. He fools the vigilante unions reps in Los Angeles into not demanding union fees by pretending that he is shooting a porno. He decides to star in the movie himself only when his money man informs him they can’t afford SAG wages.

Along the way his multiracial crew is faced with all kinds of obstacles, including his entire second unit getting arrested and thrown in jail because police mistakenly think one of their pieces of equipment is a bazooka.

By the time “Sweet Sweetback’s” is finally completed, Peebles is “hemorrhaging cash.” Then he learns the X-rating is preventing him from getting distribution, and even the few theaters who agree to show the film can’t print the offensive title in newspapers or put it on a marquee.

How the feature catches on with audiences is the stuff of legend.

Aside from these insider looks at indie moviemaking, “Baadasssss!” gains its power through the emotional complexity of its central character.

How difficult was it for Mario to portray his father as a not-very-likable guy, but one the audience can’t help but respect? He also has to direct a kid playing himself in uncomfortably graphic scenes — events Mario implies left his young self with some lingering psychological damage.

It’s certainly a complicated relationship between father and son. This range of honest emotional interplay gives the piece an added stratum of depth.

Ultimately, “Baadasssss!” is effective at detailing how guerilla filmmaking is not glamorous; sometimes it can be war.

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Perhaps Bill Cosby sums it up best. The comedian was actually a late-to-the-party investor in “Sweetback’s” and a major reason it got finished. He is among the many real-life members of the cast and crew who have their say over the end credits.

Cosby states, “To follow your dream, the first thing you need to do is wake up.”