How can something this expensive so cheapen the King Arthur legend?

The cost of “King Arthur: Legend of the Sword” was about $175 million. But it’s full of computer-generated imagery (enough already — there is a CGI battle in nearly every actioner that looks exactly like the warfare in its predecessors) that’s supposed to pass for adventure.

Director Guy Ritchie (“Snatch,” not to be confused with Amy Schumer’s new comedy, and “Sherlock Holmes”) has a pretty cool style that’s useful here. Some of his lightning-quick sequences are fasterthanthis and make for fun viewing, as though he’s telling the audience “Hey, you better pay attention and keep up.”

The idea of starting the movie with rampaging behemoth elephants the size of ancient dinosaurs wasn’t a good concept. We focus right away on the CGI, not the actors. It is, however, a dead giveaway of what’s to come that might give you a head start out of the theater if you choose not to sit through this.

We watch the orphaned Arthur, who grows up in a brothel, as he learns to fight and deceive. This isn’t the Disney version of Arthur; rather, it’s sort of a Dickens-with-more-grit approach. He’s a tough guy with a good heart who steals from Vikings and then gives it to the women working in the brothel.

Arthur is played as an adult by the capable Charlie Hunnam (television’s “Sons of Anarchy”) who just starred in the far superior “The Lost City of Z.”

At last, he ends up freeing the sword Excalibur from its stony resting place.

He also runs afoul of his uncle Vortigern (Jude Law), who has aspirations to the throne.

There’s a lot going on here, but lots of it is CGI and “Game of Thrones”-type murders most foul. In fact, the body count is surprisingly high, even for a sword-and-sorcery flick.

Law has little to do but be a scenery-chewing villain who is in cahoots with a very dark force indeed. Hunnam is good, but this character never will make the top of the list on his resume because it’s just not that interesting. The most entertaining character, perhaps, is The Mage (Astrid Berges-Frisbey, “Pirates of the Caribbean: On Stranger Tides”), who uses her magic to help Arthur.

The movie has the look and the appeal, such as it is, of a film based on a video game: Lots of running around, some pretty environments and an enjoyable scene or two. It’s below average, and it certainly isn’t the stuff of legend.