Henry Ruggs is back in the public eye ... the ex-Raiders star just showed up to a Las Vegas courthouse after a judge ordered him to appear over a missed breath test.

Ruggs entered the court in a black shirt, black pants and black bowtie -- and walked with seemingly no issues whatsoever.

Of course, the last time we saw Ruggs in public was in a courtroom on Nov. 3 -- the day after he was accused of slamming his Corvette into a Toyota and killing a woman and her dog.