Pi For Everyone: What To Expect from Standalone Mode
Hi! This is Evan, and I led development on the Looking Glass Portrait embedded software.
Ever since we launched the original Looking Glass in 2018, one of the questions we’ve gotten most frequently is: “how can I run my Looking Glass without a powerful computer attached?”
With Looking Glass Portrait, we’re excited to finally able to answer that question: we’ve embedded a Raspberry Pi 4 that functions as a player for content exported from our new software, HoloPlay Studio.
As is often the case, however, answering that question opens the door to ten new ones. I’ve been spending some time on the Looking Glass Factory Discord server trying to get a feel for people’s burning questions. Here are answers to a few of the most frequent; hopefully they can quench your curiosity!
Q: How do I connect the Raspberry Pi to Looking Glass Portrait?
A: The Raspberry Pi is permanently built inside Looking Glass Portrait with a persistent connection to one of its two HDMI inputs. You can switch between those inputs with a button press.
Q: How do I transfer content from my Mac or PC to Looking Glass Portrait?
A: The USB-C port on Looking Glass Portrait provides access to a shared internal USB drive. HoloPlay Studio, running on your Mac or PC, will generate playlists and media for your device and transfer them to that drive.
You can then switch Looking Glass Portrait into standalone mode by pressing the side button, at which point it will read and play back that media.
Q: I have a previous-generation Looking Glass. Can I still use tools like the HoloPlay Unity Plugin with Looking Glass Portrait attached to my PC or Mac?
A: Yes! HoloPlay Service, the Unity and Unreal plugins, and the existing developer tools will be updated for compatibility with Looking Glass Portrait. If you’re used to the Looking Glass software development workflow, working with the Portrait should be much the same.
Many of the third-party software tools created with the HoloPlay Core SDK should work out-of-the-box; others may require small updates from their developers to look best under the new 3:4 aspect ratio.
Q: How can I record holographic video from my Unity project for import into HoloPlay Studio?
A: The HoloPlay Unity plugin will be updated with an extension that unlocks recording of multiview video, which can then be imported into HoloPlay Studio.
Q: Can I sync content to my Looking Glass Portrait over-the-air?
A: Not yet, but we're trying to fit it into our schedule for later this year.
~~Dev Corner~~
Q: Okay, so what’s actually running on the internal Pi? Does it run its own version of HoloPlay Service and the existing Looking Glass developer tools?
A: No - the Raspberry Pi runs a minimal software image designed specifically for smooth, immediate playback of content exported from HoloPlay Studio.
Q: Will Looking Glass be providing an SDK to develop software that runs on the Raspberry Pi?
A: If you’re part of the Raspberry Pi community, you’ll know that drivers for 3D rendering and multimedia evolve on a month-to-month basis. Rather than try to leverage them and hit a moving target, we decided to optimize for stability and chose not to include real-time rendering in the current Looking Glass Portrait software.
HoloPlay Studio handles the rendering tasks that a real-time rendering API would perform; this ultimately allows us to deliver substantially higher-quality output as it frees up the more limited compute resources on the Pi itself.
Q: Will Looking Glass Factory issue upgrades for the Raspberry Pi software?
A: Yes! As HoloPlay Studio continues to expand support for different holographic media formats, we will issue updates to the Looking Glass Portrait’s own software.
As an example, one planned update will enable media sync via Wi-fi.
Q: Can I remove the Raspberry Pi from my Looking Glass Portrait, or modify the software it runs?
A: I can’t stop you! (And I wouldn’t if I could.)
Q: Why not use a Pi Compute Module?
A: There’s no guarantee that the Compute Module 4 will be consistently available in the quantities we need by the time we expect to get these into customers’ hands.
I hope this helped answer some of the most common questions we’re already starting to see!
Feel free to hop into the Looking Glass Discord channel if you think there’s anything I missed.
