Windows

It builds. Nothing has drawn yet

There’s no Windows machine behind this work, so CI is the only thing that has ever compiled the Windows plugin. A green Windows job means it compiles, links and bundles. CI launches the build too, but GitHub’s Windows runner can’t create a Vulkan instance, so the frame check gives up with “no frame after 120s”. No frame has ever been drawn on Windows, and nobody has run it on a real machine. If you have a Windows PC and half an hour, trying this page and saying on the Discord what happened is one of the most useful things you could do for the project.

Windows gets a Win32 plugin over the same renderer core, speaking the same channel with the same method names, so OrblitView and every other Dart caller works there unchanged. CMake runs the setup when Flutter configures the build, through bash, which is the one thing here Flutter doesn’t already ask for.

What you need

Windows 10 or 11, on x64	Not on Arm
Visual Studio 2022 or newer	With the “Desktop development with C++” workload, as flutter doctor asks for. The renderer is C++20 and builds with MSVC. CI compiles it with Visual Studio 2026, and 2022 hasn’t been tried
Git for Windows	For its bash, which has to be on PATH. See below
Developer Mode	Flutter needs it to link plugins. start ms-settings:developers opens the setting

Bash on PATH

The setup script is bash, and CMake looks for bash on PATH. If it finds none, the build stops with:

No bash on PATH. packages/orblit_filament/windows/setup.sh stages the
Filament release and compiles the materials, and needs the bash that
Git for Windows installs.

Git for Windows does install a bash, in C:\Program Files\Git\bin. As far as we know, its installer’s default PATH option only adds Git\cmd, which has git and no bash. So a machine where git works can still hit that error. For the current PowerShell session:

$env:Path = "C:\Program Files\Git\bin;$env:Path"
where.exe bash

To keep it, add the same folder to Path under “Edit the system environment variables”.

where.exe bash should list Git’s first. If the first one is C:\Windows\System32\bash.exe, that’s WSL’s launcher, and it would run the setup inside Linux, where it doesn’t belong. Nobody has seen what happens then, so put Git’s folder ahead of it.

CMake remembers the bash it found. If it has already found the wrong one, run flutter clean after fixing PATH.

Running it

flutter run -d windows

The first configure is the slow one. It downloads Filament’s Windows release, about 810 MB, and compiles the materials for Vulkan and OpenGL with the release’s own matc.exe.

At runtime the renderer asks for Vulkan first, through vulkan-1.dll, and falls back to OpenGL through opengl32.dll. It only falls back when vulkan-1.dll is missing or building Filament’s engine throws. On CI’s runner the DLL loads, then Filament panics creating the Vulkan instance on its own driver thread, where nothing can catch it, so OpenGL is never tried.

Each frame is copied into a flutter::PixelBufferTexture on its way to Flutter. The copy-free route is reported to crash under Impeller, and nobody has been able to check that on a real machine, so the copy stays until someone can.

x64 only

Google publishes Filament’s Windows release for x64 and nothing else, so there’s nothing to link an arm64 build against. On Windows on Arm, Flutter builds for arm64, and the plugin stops at configure time with a message saying to build with --target-platform windows-x64. That advice is wrong for now: flutter build windows has no such flag in Flutter 3.47, because it builds for whatever machine it’s on. So Windows on Arm can’t build Orblit’s renderer yet.