Sometime around 1979, Windmill Ceramic produced a set of unlicensed mugs based off of Star Wars characters. They were originally sold as blank ceramic pieces for people to paint and decorate. First I'll show you R2-D2.
The set also includes Darth Vader, though this one doesn't look as close to its screen counterpart as the R2 mug does.
I can't tell whether the stars protrude or indent from the mug because the paint job on mine is obscuring the view. Other sources also state the existence of the Windmill Ceramics Darth Vader mug with stars in his eyes, so I know mine's not the only one that's been painted this way.
There's also a less humorous version of Darth, one without stars in his eyes.
I like it when the decorators leave a note on the bottom, it gives it more of a historical feel. This one says, "Merry xmas Mike!" and the initials BH (not pictured).
Towards the bottom of the mugs, there's a very slight difference between the two. Notice in the picture below that the mug on the left (stars-in-eyes Vader) has an indent or crease running across it (vertically in the photo) while the right mug (no-stars-in-eyes Vader) is smooth.
There's still other Vaders, too. There's one that has a handle that is curved on the top half and flat on the bottom, and the top rim is shaped a bit differently. There's another mug that has its handle located on the back of Vader's head instead of the side.
Windmill Ceramics also released a Chewbacca mug. I've seen a C-3PO mug that, judging by its handle, looks to belong to this set, though I'm not sure of it. Windmill also made unlicensed ceramic lamps of Chewbacca, Darth Vader, R2-D2, and possibly C-3PO. You can read my post about those by clicking here.