I ran into Cheech Marin (of Cheech and Chong) last week and asked his opinion of the fast-growing subgenre of stoner films.

“Do you have to be stoned while you’re shooting them as well as when you’re seeing them?” I asked.

“Making a movie is too damned difficult,” Cheech assured me. “Alas, you’ve got to be straight to get through it.”

Take a look at the newest round of stoner films, however, and it’s difficult to find much entertainment value unless you bring a considerable degree of potitude. The latest effusion, “Your Highness,” is a case in point. The film is to stoner films what “Avatar” was to 3D — except that “Avatar” was pricey but brilliant while “Your Highness” is simply pricey but prurient.

The stoner subgenre dates back to 1936 and a weirdly didactic movie called “Tell Your Children” — the name was quickly changed to “Reefer Madness” — but there’s been a busy rebirth lately: think “Pineapple Express,” “Green Hornet,” “Tropic Thunder” and the “Harold & Kumar” series (a new one will emerge in November).

Inevitably, there are questions about definition: Cheech and Chong left no ambiguity about “Up in Smoke,” which astonished everyone by becoming a $100 million grosser. “Green Hornet” represents the first stoned-superhero movie — indeed, much of Seth Rogen’s dialogue is impenetrable to an audience that is weedless as well as heedless. The “Harold & Kumar” films embody a sort of pothead “Bourne” genre, with the protagonists constantly on the run — they’re not straight enough to move very quickly.

“Your Highness,” created by the “Pineapple Express” team of Danny McBride and David Gordon Green, represents a throwback to the road movies of Bob Hope and Bing Crosby, except that the dialogue is full of, well, potholes. Besides, it’s hard thinking of Hope and Crosby dealing out serial dick jokes.

“Your Highness,” which cost somewhere between $50 million and $80 million depending on who you ask, represents a breakthrough in that it’s the first stoner film to embrace the talents of two major stars. Natalie Portman was an Oscar winner this year and James Franco was not only a nominee but also almost a co-host — I say “almost” because I can’t quite remember (neither can he).

On Oscar night, some viewers wondered, regarding Franco, “What was he smoking?” My theory is that he was simply distracted by his studies of Shelley and Keats as part of his PhD program at Yale. While Franco in person is both lucid and expressive, some of his output in short subjects (he directs them), in performance art (think sudser “General Hospital”) and even the short stories he keeps publishing can be perplexing. Then there was the art show in Berlin — or was it a garage sale that happened to have bullet holes in it?

I don’t think Franco aspires to be a sort of stoner Shakespeare, but his writings and choice of roles in films like “Your Highness” inevitably will fortify that image.

The re-emergence of the stoner film points attention to another film subgenre: the should-have-been stoner movie. “Arthur” is a vivid example: The remake is so conventional and politically correct that one yearns for the characters to be transformed to an altered state. The original Arthur, as played by Dudley Moore, was an alcoholic, whoring mess. Who would ever imagine that Russell Brand would straighten out the character?

For the record, Marin, the auteur of stoner films, spends his time collecting art (his collection is vast), writing, golfing, playing music and providing vivid voices for animated films like “Cars 2.” He hasn’t seen “Your Highness,” nor does he plan to do so. Apparently he didn’t want to see his old genre go up in smoke.