The artist now has a cat, Spunky, and even a computer, though he has refused to learn how to do much with it, his brother said, adding that Mr. Johnston briefly played the iPhone game while it was being developed and seemed to like it.

Reached at his father’s house recently after he had returned from a concert tour in the Midwest, Mr. Johnston did not seem to remember much about the game or having played it. Asked what he thought of his work serving as the basis for a video game, he sighed and said, “Just another milestone in Daniel Johnston history, I guess.”

But he added that he had come of age when a video game was played with a joystick, on a television screen, usually one encased in a large wooden box with slots for quarters. “If they make it into a real video game, it might work out, I guess,” he said. “I don’t even know what an iPhone is.”