Shimmer, a free Mac app, streams PC games from Sunshine into a Picture-in-Picture window and keeps taking DualSense input

A round of Street Fighter 6 can now sit in the corner of a MacBook screen while the player types an email in front of it. The Mac app that does it is Shimmer, from Kevin Patel, and the game never runs on the Mac at all.

It runs on a PC or a headless server, and the Mac is just the window onto it. Patel’s own setup, per his announcement post, is a Bazzite server, the stock Moonlight client and Picture-in-Picture mode. What he wanted from Moonlight was its option to keep controller input going when the game window isn’t focused. Shimmer, he writes, is built “with a focus on Picture in Picture mode and pairing with a PS5 DualSense controller.”

The README on GitHub gives the mechanics. “Press ⌃⌥P during a stream and the game moves into the system Picture in Picture window,” it says, and the shortcut is one of three ways in (the menu bar and an automatic mode are the others). While the game floats over your other apps, the README says, “The controller keeps driving the game.” So you can alt-tab to a spreadsheet and still land a combo, which is a very specific way to be unproductive.

The demo clips stream Street Fighter 6 at 30 Mbps over Ethernet to a 5K display on a base M5 MacBook Pro with 16GB of RAM. Patel reports virtually no latency and no significant frame drops while he multitasks, locks and unlocks the Mac, and dictates. Those are his demo conditions, not a requirement, and the README never gives a bitrate.

The pad support is the second half of the pitch. The README lists “Xbox and DualSense controllers, including rumble, gyro and touchpad,” and Patel says DualSense controllers “get a little bit of special treatment,” down to menu bar icons that show the battery level of each connected PS5 DualSense controller. Apple and Sony’s controller relationship, he says, means pressing the PS button pairs the pad instantly.

Shimmer is a family business. Patel says it “was forked from Glimmer and developed entirely via agentic coding” (Glimmer is another Mac Moonlight client, and the lineage is mostly adjectives). The README says the streaming protocol code is ported from Moonlight, also GPLv3, and Patel says Shimmer is “licensed under the GPLv3, so it stays free and open source.”

The catch is the install. The README says building needs macOS 26 or later on Apple Silicon, Xcode 26 and Homebrew, and “A PC running Sunshine is required.” There is no download: the Releases section is empty and, in the README’s words, “There is no notarized installer yet.” Anyone who isn’t comfortable with Xcode is waiting.

Streaming from a home server to a laptop is already how plenty of people play, and the part that stays awkward is the window. Full-screen takes over the Mac, windowed fights for focus, and a corner overlay with live controller input is a third way to split attention. Slow turn-based games and anything with a long loading screen suit a game that lives in a corner, so those are the ones to watch for on a Shimmer screen.

Patel plans to leave the project alone for a while. The wish list in his post is agent loops to cut CPU use at higher bitrates, a test of Steam’s Pyrowave codec, and maybe to “perhaps replace Sunshine on the server too.” That last one would swap out the one piece the README says is required, and nobody has said what replaces it.

The fight stays in the corner.