Richard Linklater, who directed stoner classics like “Dazed and Confused” and “Waking Life,” truly trips out with “A Scanner Darkly,” a surreal version of sci-fi visionary Philip K. Dick’s split-personality, semi-autobiographical addiction story, published in 1977.

Set in Orange County, California, in 2013, the somewhat incoherent plot revolves around the paranoia of an undercover drug agent, known as Bob Arctor (Keanu Reeves), who is hooked on something lethal called Substance D (named for causing “dumbness, despair, desertion and death”) while covertly keeping under surveillance his whacked-out slacker friends, the addled James Barris (Robert Downey Jr.) and the jokster Ernie Luckman (Woody Harrelson), plus his drug-and-love connection Donna Hawthorne (Winona Ryder).

To protect his undercover identity, Bob often dons a “scramble suit,” which turns its wearer into a “vague blur” in this creepy, mind-bending exploration of alternative realities. Frankly, I found the film enough of a brain-cell challenge without the costume.

Shot in the same style as “Waking Life,” Linklater filmed the actors in the traditional live-action, and then had animators overlay each frame. Resembling a comic-book-come-to-life, it’s actually an old technique called roto-scoping, one that was utilized by pioneers like Max Fleischer and some early Disney animators, although now the painstaking hand-tracing is achieved through computer software.

While it’s often confusing in time lapses and unevenly paced, it might be noted that none of the actors had to stretch too far for their junkie personas since most are outspoken about their personal off-screen drug experiences.

On the Granger Movie Gauge of 1 to 10, “A Scanner Darkly” is a bleak, bizarre, stylistic 6. While it’s a mundane cautionary cult tale about the perils of drug abuse, a curious visual appeal is what distinguishes this film.