feat: turn Deck mode on for new installs and add a performance overlay toggle (#101)

* feat: turn Deck mode on for new installs and add a performance overlay toggle

* feat: hide the session fps HUD where Deck mode's performance overlay runs

app/src/main/java/com/droiddeck/launcher/App.kt

@@ -12,6 +12,8 @@ class App : Application() {
     override fun onCreate() {
         super.onCreate()
         CrashHandler.install(this)
+        // Before anything else touches the session prefs: a new install's first read decides it.
+        com.droiddeck.launcher.session.SessionPrefs.settleDeckModeDefault(this)
         BwrapSpawner.start(this)
     }
 }

app/src/main/java/com/droiddeck/launcher/MainActivity.kt

@@ -105,6 +105,7 @@ class MainActivity : ComponentActivity() {
     private var glThread by mutableStateOf(true)
     private var noGlError by mutableStateOf(true)
     private var steamDeckMode by mutableStateOf(false)
+    private var mangoapp by mutableStateOf(true)
     private var steamController by mutableStateOf(SessionPrefs.CONTROLLER_DECK)
     private var showProtons by mutableStateOf(false)
     // Components page: FEX / DXVK / VKD3D-Proton per Proton (ComponentsManager).
@@ -899,6 +900,7 @@ class MainActivity : ComponentActivity() {
                 fexPreset = if (mode == SessionService.MODE_STEAM) fexPreset else null,
                 steamChannel = if (mode == SessionService.MODE_STEAM) steamChannel else null,
                 steamDeckMode = mode == SessionService.MODE_STEAM && steamDeckMode,
+                mangoapp = mangoapp,
                 steamController = if (mode == SessionService.MODE_STEAM) steamController else null,
                 runSteamAtStartup = mode == SessionService.MODE_STEAM && runSteamAtStartup,
                 addedGamesDirs = if (mode == SessionService.MODE_STEAM) addedGamesDirs else null,
@@ -956,6 +958,7 @@ class MainActivity : ComponentActivity() {
                     steamDeckMode = on
                     steamChannel = SessionPrefs.steamChannel(this)
                 },
+                onMangoapp = { on -> SessionPrefs.setMangoapp(this, on); mangoapp = on },
                 onSteamController = { id -> SessionPrefs.setSteamController(this, id); steamController = id },
                 onRunSteamAtStartup = { on ->
                     SessionPrefs.setRunSteamAtStartup(this, on)
@@ -1042,6 +1045,7 @@ class MainActivity : ComponentActivity() {
         fexPreset = SessionPrefs.fexPreset(this)
         steamChannel = SessionPrefs.steamChannel(this)
         steamDeckMode = SessionPrefs.steamDeckMode(this)
+        mangoapp = SessionPrefs.mangoapp(this)
         steamController = SessionPrefs.steamController(this)
         runSteamAtStartup = SessionPrefs.runSteamAtStartup(this)
         addedGamesDirs = SessionPrefs.addedGamesDirs(this)

app/src/main/java/com/droiddeck/launcher/session/SessionPrefs.kt

@@ -44,12 +44,23 @@ object SessionPrefs {
         prefs(context).edit().putBoolean("appImagesEnabled", on).apply()
     }
 
-    fun hudEnabled(context: Context): Boolean = prefs(context).getBoolean("hud", true)
+    /**
+     * The session's performance HUD (the fps box). A Deck-mode Steam session with the performance
+     * overlay has Steam's own (mangoapp, from the QAM), so there the HUD is off unless turned on
+     * in one - a choice kept apart from every other session's, where it stays on by default.
+     */
+    fun hudEnabled(context: Context): Boolean = prefs(context).getBoolean(hudKey(context), !mangoappSession(context))
 
     fun setHudEnabled(context: Context, on: Boolean) {
-        prefs(context).edit().putBoolean("hud", on).apply()
+        prefs(context).edit().putBoolean(hudKey(context), on).apply()
     }
 
+    private fun hudKey(context: Context) = if (mangoappSession(context)) "hudDeck" else "hud"
+
+    /** A Steam session that runs Deck mode with its performance overlay (mangoapp). */
+    private fun mangoappSession(context: Context) =
+        SessionState.mode == SessionService.MODE_STEAM && steamDeckMode(context) && mangoapp(context)
+
     /** When enabled, a single Back opens Steam QAM and a double Back opens the session menu. */
     fun backActionsInverted(context: Context): Boolean = prefs(context).getBoolean("backActionsInverted", false)
 
@@ -292,10 +303,30 @@ object SessionPrefs {
         prefs(context).getString("steamController", CONTROLLER_DECK) ?: CONTROLLER_DECK
     fun setSteamController(context: Context, id: String) { prefs(context).edit().putString("steamController", id).apply() }
 
-    /** Runs the SteamOS gamepad client with its Quick Access performance controls. */
-    fun steamDeckMode(context: Context): Boolean = prefs(context).getBoolean("steamDeckMode", false)
+    /** Runs the SteamOS gamepad client with its Quick Access performance controls. On for new installs (settleDeckModeDefault). */
+    fun steamDeckMode(context: Context): Boolean = prefs(context).getBoolean("steamDeckMode", true)
     fun setSteamDeckMode(context: Context, on: Boolean) { prefs(context).edit().putBoolean("steamDeckMode", on).apply() }
 
+    /**
+     * Deck mode became the default for new installs; an install from before keeps what it ran with
+     * (off), so an update never changes its interface or restarts the client on its own. Run once at
+     * process start, before anything reads or writes these prefs: a new install has neither prefs
+     * nor a runtime yet. The answer is written down, so it is decided once.
+     */
+    fun settleDeckModeDefault(context: Context) {
+        val p = prefs(context)
+        if (p.contains("steamDeckMode")) return
+        val existing = p.all.isNotEmpty() || java.io.File(context.filesDir, "linuxfs").exists()
+        p.edit().putBoolean("steamDeckMode", !existing).apply()
+    }
+
+    /**
+     * Deck mode's performance overlay (mangoapp, beside gamescope): the QAM's Overlay Level draws
+     * through it. Off is the way out where Valve's mangoapp crashes (one Turnip build did).
+     */
+    fun mangoapp(context: Context): Boolean = prefs(context).getBoolean("mangoapp", true)
+    fun setMangoapp(context: Context, on: Boolean) { prefs(context).edit().putBoolean("mangoapp", on).apply() }
+
     /**
      * Zink's lazy descriptor mode (ZINK_DESCRIPTORS=lazy) with its compact set layout
      * (ZINK_DEBUG=compact) for the client's GL-on-Vulkan UI, as WinNative runs it. On by default.

app/src/main/java/com/droiddeck/launcher/session/SessionService.kt

@@ -528,6 +528,7 @@ class SessionService : Service() {
         if (SessionPrefs.glThread(this)) guest.add("mesa_glthread=true")
         if (SessionPrefs.noGlError(this)) guest.add("MESA_NO_ERROR=1")
         if (SessionState.mode == MODE_STEAM) guest.add("BL_STEAMDECK=" + (if (SessionPrefs.steamDeckMode(this)) "1" else "0"))
+        if (SessionState.mode == MODE_STEAM) guest.add("BL_MANGOAPP=" + (if (SessionPrefs.mangoapp(this)) "1" else "0"))
         if (steamHere) guest.add("BL_STEAM_CHANNEL=" + SessionPrefs.steamChannel(this))
         if (SessionState.mode == MODE_STEAM) {
             guest.add("BL_GAMESCOPE_FORCE_FULLSCREEN=" + (if (SessionPrefs.forceFullscreen(this)) "1" else "0"))

app/src/main/java/com/droiddeck/launcher/ui/ModeSettingsDialog.kt

@@ -70,6 +70,8 @@ class ModeSettings(
     val steamChannel: String? = null,
     /** Steam only: enable the SteamOS client interface and its performance controls. */
     val steamDeckMode: Boolean = false,
+    /** Steam, Deck mode: the QAM's performance overlay (mangoapp) is started. */
+    val mangoapp: Boolean = true,
     /** Steam only: what the pad is to the client (SessionPrefs.CONTROLLER_*); null outside Steam. */
     val steamController: String? = null,
     /** Steam only: start a Steam session when DroidDeck opens. */
@@ -128,6 +130,7 @@ class ModeSettingsActions(
     val onForceFullscreen: (Boolean) -> Unit = {},
     val onSteamChannel: (String) -> Unit = {},
     val onSteamDeckMode: (Boolean) -> Unit = {},
+    val onMangoapp: (Boolean) -> Unit = {},
     val onSteamController: (String) -> Unit = {},
     val onRunSteamAtStartup: (Boolean) -> Unit = {},
     val onPickAddedGamesDir: () -> Unit = {},
@@ -359,6 +362,11 @@ fun ModeSettingsPage(s: ModeSettings, a: ModeSettingsActions) {
                 "Enables Steam's Deck interface and Quick Access performance overlay controls. Applies next session.",
                 s.steamDeckMode, onChange = a.onSteamDeckMode,
             )
+            if (s.steamDeckMode) ToggleRow(
+                host, "mangoapp", "Performance overlay",
+                "The Quick Access Menu's frame-rate and usage overlay. Turn off if games crash or go black with Deck mode on. Applies next session.",
+                s.mangoapp, onChange = a.onMangoapp,
+            )
             // Deck mode fixes the branch (SessionPrefs.steamChannel); the choice is for Deck mode off.
             if (s.steamDeckMode) SettingsRow("Client branch", "Steam Deck public beta: Deck mode needs it, so Steam doesn't keep offering an update") {}
             else ChoiceRow(