Platform layer

A core rule of the codebase: gameplay code should not contain platform conditionals. Platform differences are pushed into a small number of modules that expose a clean cross-platform API and compile to no-ops elsewhere.

Layer	Where
Platform detection	utils.PlatformUtil
Desktop natives (Win32, POSIX)	utils.PlatformUtilNative, utils.CoolSystemStuff, utils.HiddenProcess
Memory reporting	utils.MemoryUtil, debug.Memory, debug/mem/ (C++ include)
Mobile storage, permissions, touch	mobile/
Android services	android/platform/*.hx + android/src/quack/fnf/phoenix/android/*.java
Window behaviour	backend.WindowBackend, backend.WindowColorMode, backend.TransparentWindow, backend.FlxTransWindow, backend.FunkinGame
Library-level fixes	source/source-haxelib-patches/ (details)

Desktop

• Windows. Main runs SetProcessDPIAware(), SetConsoleOutputCP(CP_UTF8) and DisableProcessWindowsGhosting() through inline C++, linking wininet.lib and dwmapi.lib via @:buildXml. WindowColorMode applies the dark title bar through DWM. utils.PlatformUtil.detectWine() reports whether the Windows build is running under Wine. backend.TransparentWindow drives the see-through window effect through backend.FlxTransWindow (a port of the same class in psych-engine-modified-build): it resolves the HWND of the current process instead of trusting GetActiveWindow(), then applies WS_EX_LAYERED with a color key and whole-window alpha in a single SetLayeredWindowAttributes() call, plus WS_EX_TRANSPARENT for click-through.
• Linux. hxgamemode is requested in Main.__init__() behind GAMEMODE_ALLOWED and released in shutdownGameMode(); both paths tolerate gamemoded being absent. gamemode.ini is the shipped profile. Video decoding is libvlc through hxvlc.
• macOS. FEATURE_FILE_DROP is disabled (drag-and-drop does not work there); sys/utsname.h is included for the arch query in utils.PlatformUtil.getArch().

Android

The Android integration is the largest platform-specific surface. It is documented in depth in docs/ANDROID_PLATFORM.md; the structure is:

Gameplay code
  └─ android.platform.*          (Haxe API, no-ops off Android)
       └─ AndroidBridge.hx       (cached JNI handles + event dispatch)
            └─ android/src/quack/fnf/phoenix/android/*.java

Haxe module	Responsibility
AndroidPlatform	boots the whole layer from Main
AndroidBridge	JNI helpers and the Java → Haxe event dispatcher
AndroidLifecycle	pause/resume/stop, focus
AndroidMedia	MediaSession / Media3 metadata, playback state, lock-screen controls
AndroidDisplay	insets, cutouts, refresh rate, immersive mode
AndroidStorage	scoped storage and permissions
AndroidHardwareInput, AndroidGamepad, AndroidHaptics	physical keys, controllers, vibration
AndroidIntents, AndroidNotification, AndroidDiscord, AndroidSystem	intents, notifications, RPC, system info

Java side: PhoenixCore (registration + dispatch(event, arg)), PhoenixMedia and PhoenixMediaService (a Media3 MediaSession / MediaSessionService mirror for background media-session visibility and external controls), PhoenixDisplay, PhoenixStorage, PhoenixInput. The extension classes are registered through config.push("android.extension", ...) in project.hxp, and Lime's GameActivity instantiates them. project.hxp also adds the Android-only source/android/media3 Gradle shim, which pins androidx.media3:media3-session without affecting desktop, web or iOS builds.

Data crossing the boundary: arrays become CSV strings, byte buffers go through haxe.io.Bytes.ofData, and JNI method handles are created lazily and cached.

Build-time Android work also lives in project.hxp: configureAndroidRuntime() copies libc++_shared.so from the NDK into the Gradle project (why).

iOS

lime build ios -nosign in CI. Native tweaks (fullscreen, orientation, lifecycle) go through templates/ plist/Xcode settings and the shared mobile/ modules. Objective-C / Swift injections are applied by the project script, not scattered through source/.

Web, Flash and AIR

These targets lose whole feature flags: no MODS_ALLOWED, no LUA_ALLOWED / PYTHON_ALLOWED, no VIDEOS_ALLOWED, and on SWF no SHADERS_ALLOWED. HTML5 embeds assets (EMBED_ASSETS) and uses mp3 rather than ogg.

Flash/AIR additionally rely on the seven files in source/source-haxelib-patches/, which gate out library APIs that only exist on the Lime/OpenFL renderers.

Adding platform-specific behaviour

1. If it can be expressed in Haxe against an existing library API → write it in the relevant utils/, mobile/ or android/platform/ module, behind #if.
2. If it needs library changes → add a patch in source/source-haxelib-patches/.
3. If it needs C/C++, Java/Kotlin, Objective-C or Win32 → put the native source under android/src/, templates/ or an inline @:cppFileCode block, and wire it up from project.hxp (build callbacks, setup/ scripts).

Expose the result as a cross-platform function with a no-op fallback, so callers never need their own #if.