👉 The Windows flavor runs the Avalonia port on Avalonia's Windows backend. It is the quickest way to develop and test the port without a Linux computer, and an alternative to the WinUI 3 version that Windows players get, one in which the Steam overlay works. This page covers what is specific to it, and how it differs from the WinUI 3 version.

The design that every flavor shares is on Design Details of Avalonia Port; building is on Build Instructions for Avalonia Windows Version on Windows.

ℹ️ At a Glance

   
Purpose Development and testing of the Avalonia port, and an alternative Windows version; not shipped to players yet
Runtime identifier win-x64, the default when -p:GnhAvalonia=true is built on Windows
Symbols WINDOWS_AVALONIA and SENTRY, never WINDOWS; see Build Configuration Per Flavor
Game engine and data The WinUI 3 version's gnollhackwin.dll and Windows-format nhdat
Rendering Direct3D 11 through ANGLE, on a DXGI flip-model swap chain of the window (LowLatencyDxgiSwapChain)
Web view Microsoft Edge WebView2, which must be installed; see Web View
Game controllers XInput
Crash reporting Sentry, including native crashes, through the WinUI 3 version's gnhsentry.dll
Single instance instance.lock in the data folder; a second copy says so and exits. Windows has no termination signals: a logoff ends Avalonia's lifetime, after which the game saves
Executable A GUI program; standard output and error go to Logs\GnollHack.log in the data folder
Data folder %LOCALAPPDATA%\GnollHack-Avalonia; see Files and Folders
Distribution A zipped self-contained publish folder; no installer, no MSIX package and no Steam depot yet
Manifest Platforms\Avalonia\app.manifest, used on Windows only
Paths Platforms\ means win\win32\xpl\GnollHackM\Platforms\ in the GnollHack repository

🧠 Design Decisions

Decision Choice Why
Why it exists A Windows build of the Avalonia port, for testing and as an alternative to the WinUI 3 version The quickest loop for an Avalonia change: it builds with dotnet alone, starts without WSL, and Visual Studio can attach its debugger to the process. Unlike WinUI 3, it can give the Steam overlay a swap chain to draw on
WINDOWS_AVALONIA, not WINDOWS Plain net11.0, not a -windows target framework, with a symbol of its own WINDOWS marks the WinUI 3 version's code; for the same reason the platform name is "WindowsAvalonia", so GHApp.IsWindows stays false and GHApp.IsWindowsAvalonia is the run-time check
Composition LowLatencyDxgiSwapChain, then WinUIComposition, then RedirectionSurface Steam's overlay draws on a window swap chain's Present. Avalonia's default, Windows composition, never presents one, so the overlay never appeared with it (WA-STEAM-0003). In the Steam overlay test of November 2026 the swap chain also ran the map faster
GPU The high-performance GPU, unless Windows' per-app graphics setting for the executable says Power saving Avalonia otherwise takes the first adapter Windows lists, which is the integrated GPU on most hybrid laptops; in November 2026 the map ran GPU-bound at 40 fps there instead of 60
Overlay keep-alive While Steam's overlay library is loaded, a 1 × 1 visual is redrawn about 30 times a second on pages that draw nothing Avalonia presents only when something changed, so the overlay could not open over a still menu
Screen resolution The WinUI 3 version's display mode change, made with CDS_FULLSCREEN The mode ends with the process, so a crash cannot leave the desktop at the game's resolution
Secure storage Windows' data protection (DPAPI) for the current user A key from the computer's name could be rebuilt by anyone; a store in the older format is converted the first time it is read
Executable A GUI program with its own icon, logging to a file A console window would open beside the game when it is started from Explorer or Steam
Data folder %LOCALAPPDATA%\GnollHack-Avalonia, apart from the WinUI 3 version's Testing never touches the WinUI 3 version's saved games and settings on the same computer
Window icon A multi-size icon, built at run time with smooth filtering Windows picks the matching size from an icon, but scales a single large image with point sampling
Application manifest Lists the supported operating systems, Windows 10 and 11 Without the list, Avalonia cannot create the child windows that host native controls, such as the web view
WebView2 user data WebView2\ in the data folder WebView2's default, a folder next to the executable, may not be writable

📁 Files

The Windows flavor's own C# is in Platforms\WindowsAvalonia\; Platforms\Windows\ is the WinUI 3 version's, and the Avalonia build never compiles it. Paths are relative to Platforms\ except the last five:

File Role
WindowsAvalonia\GHWindowsStderrLog.cs Standard output and error, the engine's included, to Logs\GnollHack.log
WindowsAvalonia\GHAvaloniaWindowsKeyHook.cs The low-level keyboard hook behind Disable Windows Key
WindowsAvalonia\GHWindowsGpuSelection.cs Chooses the GPU Avalonia renders on, and reports it to the performance test
WindowsAvalonia\appicon.ico, WindowsAvalonia\Packaging\New-WindowsAppIcon.ps1 The executable's icon, and the script that makes it from Resources\AppIcon\appicon.png
Windows\libs\ The game engine, gnollhackwin.dll, built by win\win32\vs\gnollhackwin.vcxproj and not in Git; gnhsentry.dll; FMOD's fmod.dll, fmodstudio.dll and its other libraries
Windows\gnh\ The Windows-format nhdat and the other game data files
Avalonia\app.manifest Supported operating systems and per-monitor DPI awareness
win\win32\xpl\GnollHackM\GHXInputGamepadBackend.cs XInput controllers, shared with the WinUI 3 version
win\win32\xpl\GnollHackM\NativeLibraryPreflightWindows.cs Why a native library failed to load, and the Smart App Control tag of crash reports; shared with the WinUI 3 version
win\win32\xpl\GnollHackM\GHSentryNative.cs sentry-native through gnhsentry.dll, shared with the WinUI 3 version
win\win32\xpl\GnollHackM\GHDxgiAdapters.cs The Direct3D adapter list and the high-performance and power-saving adapters, shared with the WinUI 3 version
win\win32\xpl\GnollHackM\GHWindowsGpuChoice.cs The GPU rule and the "Multiple GPUs" alert rule, without Windows calls, so the unit tests can check them

  • Composition switch: --win-composition=<mode> or GNOLLHACK_WIN_COMPOSITION picks dxgi, winui, dcomp, redirect, wgl or avalonia (Avalonia's own defaults), for testing. The log's GnollHack: Windows composition request line names the render timer that was applied.

  • GPU switch: --win-gpu=<mode> or GNOLLHACK_WIN_GPU picks auto (the default: the high-performance GPU unless Windows says Power saving), dedicated, integrated or avalonia (Avalonia's own first adapter), for testing. The log's GnollHack: Windows GPU line names the adapter that was chosen. The choice applies only to ANGLE on Direct3D 11, so with --win-composition=wgl it applies only when OpenGL is unavailable, and ARM64 builds keep Avalonia's own rule.

  • libs\ is copied whole, so files only the WinUI 3 version needs, such as its native crash reporter gnhsentry.dll, land in the output too. Avalonia's own Direct3D translation layer is named av_libglesv2.dll, so it does not clash with the WinUI 3 version's libGLESv2.dll.

⚖️ Compared with the WinUI 3 Version

  🪟 Windows Avalonia 🪟 WinUI 3
Purpose Development, testing, and an alternative Windows version Released to players
User interface .NET MAUI on Avalonia.Controls.Maui .NET MAUI on WinUI 3
.NET .NET 11, SDK pinned in Platforms\Avalonia\global.json .NET 10, SDK pinned in GnollHackM\global.json
Game engine and data gnollhackwin.dll, Windows-format nhdat The same
Rendering ANGLE on the window's DXGI swap chain SkiaSharp on a SwapChainPanel, or a XAML Canvas without GPU acceleration
GPU The high-performance GPU, unless Windows' per-app setting says Power saving, chosen through Avalonia's adapter callback The same rule while GPU Acceleration is on, applied by initializing ANGLE's display on that GPU before SkiaSharp creates it; with GPU Acceleration off, Windows' default GPU
Steam overlay Draws over the game; tested on the map in November 2026 Does not appear
Web view WebView2 through Avalonia WebView2 through .NET MAUI
Crash reporting Sentry, including native crashes The same
Windows-only settings Screen Resolution, Disable Windows Key, Right and Middle Mouse Button The same
Data folder %LOCALAPPDATA%\GnollHack-Avalonia The app's own data folder
Distribution A zipped folder MSIX and Steam

🐞 Crash Reporting

The shared model is in Crash Reporting. On Windows:

  • sentry-native: gnhsentry.dll, the same file as the WinUI 3 version's, with GnollHack's crash shim: a filter that keeps CoreCLR's unhandled-exception filter in the chain, and a vectored handler that reports faults in the game engine, SkiaSharp, FMOD and ANGLE under .NET code. Its module list names the WinUI 3 version's ANGLE files, not this flavor's av_libglesv2.dll.
  • Tags: windows.package (steam or unbundled), windows.sac_state (the Smart App Control state), and native_load.file and native_load.win32_error when a native library fails to load.
  • Debug symbols: a Release publish uploads gnollhackwin.pdb and, from the computer that built the committed DLL, gnhsentry.pdb.
  • The whole mechanism is on Design Details of Native Crash Reporting, and how gnhsentry.dll is rebuilt on Build gnhsentry.dll.

⚠️ Workarounds

The Windows flavor's workarounds are in the shared Avalonia code and recorded with the others; see Workarounds.

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