Merc Keyboard Mapper

Windows user-mode mapper for the SteelSeries Merc Stealth keyboard.

The app runs as a native Win32 tray GUI with a small .NET 8 mapper engine. It maps observable Merc gamepad keys to normal keyboard scan-code output and suppresses browser/media/app-launch side effects where Windows user mode allows it.

Install

Download the installer from the GitHub release:

https://github.com/PatrickQuintal/merc-driver/releases/download/v1.0.1/MercKeyboardMapperSetup.exe

The setup wizard installs to:

%ProgramFiles%\Merc Keyboard Mapper

It creates Start Menu shortcuts, registers a normal Windows Settings > Apps uninstall entry, and can launch the mapper after installation. Windows will ask for administrator permission during install.

Runtime requirements:

• Requires the normal .NET 8 Runtime x64.
• Does not require the .NET Desktop Runtime.
• If the runtime is missing, setup opens the Microsoft runtime installer link.

Uninstall from Windows Settings > Apps > Installed apps, or run:

& "$env:ProgramFiles\Merc Keyboard Mapper\MercKeyboardMapperUninstall.exe" --uninstall

Use

When MercKeyboardMapper.exe is running, the mapper is active. Closing the window hides it to the system tray. Use the tray icon's Exit command to stop the mapper.

The GUI provides:

• mapper status and recent logs
• mapping table search
• Q/refresh mapping toggle
• repeat timing controls
• per-user Windows startup toggle

Startup registration uses:

HKCU\Software\Microsoft\Windows\CurrentVersion\Run

Project Layout

• apps/merc-mapper/src/Merc.Mapper.Core/ - mapper runtime, startup registration, mapping catalog, and Windows interop
• apps/merc-mapper/src/Merc.Mapper/ - console runner and production mapper engine
• apps/merc-mapper/native/MercShellHook/ - native GUI wrapper, shell hook, setup wizard, and uninstaller
• apps/merc-mapper/tests/Merc.Mapper.Tests/ - mapper, packaging, and behavior tests
• apps/merc-mapper/package-release.cmd - Windows release packager
• apps/merc-mapper/test-release-smoke.ps1 - installer smoke test

Build

Build and test from WSL:

dotnet build apps/merc-mapper/src/Merc.Mapper/Merc.Mapper.csproj -c Debug
dotnet test apps/merc-mapper/tests/Merc.Mapper.Tests/Merc.Mapper.Tests.csproj -c Debug

Package the Windows release from a Windows filesystem checkout or staged copy:

apps\merc-mapper\package-release.cmd

The package command builds the native hook, GUI wrapper, setup wizard, uninstaller, and framework-dependent mapper engine. The stable local output folder is:

C:\Users\pat_q\Desktop\merc-mapper-run

Do not create versioned desktop folders for normal iteration.

Input Boundary

The mapper handles keys that Windows exposes to user mode through Raw Input, low-level keyboard hooks, shell app-command hooks, or related APIs.

Some Merc keys primarily report as keypad/home-cluster events. Those mappings are enabled by default so crouch and the left gamepad number cluster work in the installed app. The production GUI does not expose a toggle for this path; the development console can disable it with --no-keypad-cluster for controlled testing.

Keys that are invisible to normal Windows user-mode input APIs are outside this mapper's scope.

Testing

Release validation should include:

dotnet test apps/merc-mapper/tests/Merc.Mapper.Tests/Merc.Mapper.Tests.csproj -c Debug

apps\merc-mapper\package-release.cmd

apps\merc-mapper\test-release-smoke.ps1

Additional test details are in:

apps/merc-mapper/TESTING.md