In a Dream: 4 of 5 stars

Jeremiah Zagar points his camera at his artistic parents for his warts-and-grout-and-all documentary In A Dream. His mother is Julia, a gallery owner and long-suffering wife to the wildly eccentric (to put it mildly) mosaic artist Isaiah Zagar, a man who has covered many a Philadelphia building, inside and out, with stunning, epic mosaics detailing his obsessions with his family, himself and, as the film progresses, a woman he has an affair with.

The Zagars are creative folk, yes, but they’re also a family with mental illness problems (Isaiah attempted suicide in his 20s, and seems a bit mad), substance abuse problems (Jeremiah’s brother is in and out of rehab). What’s fascinating in this HBO film is the way it captures how Isaiah is kept well by his industriousness. Hurled into these massive mosaics -- which he does pretty much by himself -- he loses himself in the work. As he slips into his affair with an assistant, the work becomes uglier -- cluttered walls of bicycle wheels and beer bottles. Gone are the striking, clean and reflective surfaces that dazzle in many a scene.

Jeremiah’s movie crosses into “too much information” as dad celebrates the tactile glories of feces and the naked wonders of his and his wife’s bodies. But it’s a revealing portrait of the life of a “mad artist” and the one thing that keeps him sane.

Screening at: 4:45 p.m. Sunday, March 29, Regal; 9 p.m. Wednesday, April 1, Regal.