Set-up guide · Reefglass

Reefglass as your desktop

Run the reef live behind your windows on a Mac, or use it on Windows. About ten minutes, using free apps.

Guide version 0.2 · 14 October 2026 · For the free offline Reefglass file

Early guide. We have written these steps carefully but have not yet followed every one on a clean Mac or Windows PC. If a step does not match what you see, email contactus@launchpadtechnology.co.uk.

The two options

Live Mac desktop: the real reef, following your clock, running behind your windows. Uses Plash, a free app from the Mac App Store.
Windows desktop: uses Lively Wallpaper, a free, open-source app. Reefglass is built and tested on Mac first; on Windows it should work but is less tested.

Plash and Lively Wallpaper are made by independent developers, not by us. We link to them; we don't bundle or control them.

Before you start

Download the file from the Reefglass page and make a permanent folder for it, for example a folder called Glass Worlds in your home folder. Move reefglass-1.1.0-rc.3.html (the number may differ) into it.
Don't leave it in Downloads, or in a folder that iCloud can offload. If macOS removes the local copy to save space, the wallpaper goes blank.
Check it runs: double-click the file. It opens in your browser and the reef appears. If it doesn't, see If something goes wrong before going further.

Battery and graphics: read this first

Reefglass is a live 3D world, not a video. As a wallpaper it redraws the scene up to 30 times a second, all the time it is visible. That means:

It uses your graphics processor continuously and some memory. On a laptop running on battery, expect noticeably shorter battery life. On some Macs, especially older Intel models, you may hear the fans.
Wallpaper mode is capped at 30 frames per second (a normal browser tab can run at 60 or more). You can lower the cap further (see Settings).
It steps its own detail down if your Mac can't keep up, and steps back up when it can.
We haven't measured a power figure, so we don't quote one.

Our advice: turn on Plash's option to switch off on battery (step 5 below), so the live reef only runs when you're plugged in. On battery, the video loop is usually a much lighter choice than live 3D.

Mac: live desktop with Plash

Plash is a free menu-bar app by Sindre Sorhus that shows a web page as your desktop background, above your normal wallpaper and below your desktop icons.

Install Plash from the Mac App Store (search for "Plash"). Open it; a Plash icon appears in the menu bar at the top of your screen.
Find your file's address. In Finder, open your Glass Worlds folder, drag reefglass-1.1.0-rc.3.html onto a browser window, and copy the address from the address bar. It starts with file:///Users/.
Add wallpaper mode to the end of the address. Paste the address somewhere you can edit it, and add this to the very end:
```
#mode-wallpaper,time-live
```
so the whole thing looks like:
```
file:///Users/yourname/Glass%20Worlds/reefglass-1.1.0-rc.3.html#mode-wallpaper,time-live
```
mode-wallpaper hides the controls, switches to the underwater dive view and caps the frame rate at 30 fps. time-live keeps the reef's day and night in step with your Mac's clock. (The usual form, ?mode=wallpaper&time=live, also works where an app keeps it.)
Add it to Plash. Click the Plash menu-bar icon, choose to add a website, paste the full address from step 3, and save. The reef appears behind your windows.
Save your battery. In Plash's settings, turn on the option to deactivate while on battery.
Optional: to poke at the reef, turn on Browsing Mode in the Plash menu; turn it off again so clicks go to your desktop. If you have several displays, choose which one Plash uses in its settings (Plash shows one website at a time).

If Plash won't open the file address: some ways of adding to Plash don't accept file:// addresses. If yours doesn't, you can serve the folder on your own Mac only. Open Terminal and run:

cd ~/"Glass Worlds" && python3 -m http.server 8765 --bind 127.0.0.1

Then add http://127.0.0.1:8765/reefglass-1.1.0-rc.3.html?mode=wallpaper&time=live to Plash. This only works while that Terminal window stays open, and it is only reachable from your own Mac. (macOS may ask to install its command line tools the first time.) Glass Worlds for Mac, planned for later and free for buyers, will remove this step.

Windows: Lively Wallpaper

Lively Wallpaper is a free, open-source app (GPL-3.0) that can use a web page as your Windows desktop. It needs Windows 10 (version 1809 or later) or Windows 11.

Install Lively Wallpaper from the Microsoft Store (search "Lively Wallpaper"), or from its GitHub releases page.
Add Reefglass. Open Lively and drag reefglass-1.1.0-rc.3.html from your Glass Worlds folder into the Lively window, or use its add-wallpaper button and choose the file. If Lively lets you enter an address instead, use the file address with #mode-wallpaper,time-live on the end, as in the Mac steps.
Set it as your wallpaper. If the reef shows its on-screen controls, wallpaper mode wasn't picked up; use the address method.
Save power. In Lively's settings, keep wallpapers pausing when a full-screen app or game is running, and turn on pausing while on battery.

Settings you can add

Add these to the end of the address, after # as name-value pairs separated by commas (or after ? as name=value joined by &).

Setting	What it does
`mode-wallpaper`	No controls, dive view, slow drifting camera, 30 fps cap. Use this for any wallpaper.
`time-live`	Follow your device's clock for day, dusk and night. Without it, the reef opens at midday and runs in real time from there.
`fps-20`	Lower the frame cap (try 20 or 15) to use less power. Movement looks less smooth.
`quality-medium`	Start at a lower detail level: `low`, `medium`, `high` (default) or `ultra`. It still steps down on its own if needed.
`interactive-0`	Ignore the mouse completely.
`view-tank`	Show the whole glass case instead of the underwater view.

Example, a lighter setting for an older laptop:

…reefglass-1.1.0-rc.3.html#mode-wallpaper,time-live,fps-20,quality-medium

If something goes wrong

Black or blank wallpaper: check the file is still where you put it and hasn't been offloaded to iCloud. Open it directly in Safari; if it doesn't run there, your Mac's graphics may not support WebGL 2.
Controls are showing: the wallpaper settings didn't reach the page. Check the end of the address.
Day and night are wrong: add time-live.
Mac is warm or the battery drains: add fps-20,quality-medium, and make sure Plash is set to switch off on battery.
Still stuck? Email contactus@launchpadtechnology.co.uk with your Mac or PC model and operating system version.

Plash is by Sindre Sorhus and Lively Wallpaper by rocksdanister. They are independent of Launchpad Technology. The Reefglass file is free for homes, shops, schools and businesses. For a custom world or tailored learning content, contact us.