Google is getting real about virtual reality.

The Alphabet Inc. unit is developing an all-in-one virtual-reality headset that doesn’t rely on a smartphone, computer or game console, according to people familiar with the matter. That would be a first in the rapidly evolving field.

Google also plans to release later this year a more advanced version of its $20 cardboard virtual-reality viewer that uses a smartphone as a screen, people familiar with the matter said. The new plastic viewer will include computer chips and sensors, these people said.

The new devices are the latest evidence of Google’s growing interest in virtual reality and will thrust the tech giant more fully into competition with Facebook Inc., whose Oculus unit plans to start shipping a $599 headset next month that runs off a personal computer.

HTC Corp. and Sony Corp. also plan headsets this year that require a PC or game console, while Samsung Electronics Co. began selling a $100 viewer in November that uses the company’s phones.