fix: draw the gamescope cursor only when that option is on

The extra plane costs frames on a phone, so compositing stays off unless Performance asks for it.

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

@@ -155,6 +155,7 @@ class FrontEndActivity : ComponentActivity() {
     private var gpuClockPin by mutableStateOf(false)
     private var prootNoSeccomp by mutableStateOf(false)
     private var prootFastPath by mutableStateOf(true)
+    private var cursorComposite by mutableStateOf(false)
     private var guestHostname by mutableStateOf(SessionPrefs.DEFAULT_GUEST_HOSTNAME)
     private var phantomWarning by mutableStateOf<String?>(null)
     private var phantomProcessStatus by mutableStateOf(PhantomProcessStatus.NOT_APPLICABLE)
@@ -1771,7 +1772,8 @@ class FrontEndActivity : ComponentActivity() {
             fsyncFirst = fsyncFirst,
             gamescopeRealtime = gamescopeRealtime,
             gpuClockPin = gpuClockPin,
-            prootNoSeccomp = prootNoSeccomp, prootFastPath = prootFastPath, guestHostname = guestHostname, phantomWarning = phantomWarning,
+            prootNoSeccomp = prootNoSeccomp, prootFastPath = prootFastPath, cursorComposite = cursorComposite,
+            guestHostname = guestHostname, phantomWarning = phantomWarning,
             onClientOverride = { on -> SessionPrefs.setClientCpusOverride(this, on); clientOverride = on },
             onTuSysmem = { on -> SessionPrefs.setTuSysmem(this, on); tuSysmem = on },
             onZinkLazy = { on -> SessionPrefs.setZinkLazy(this, on); zinkLazy = on },
@@ -1785,6 +1787,7 @@ class FrontEndActivity : ComponentActivity() {
             onGpuClockPin = { on -> SessionPrefs.setGpuClockPin(this, on); gpuClockPin = on },
             onProotNoSeccomp = { on -> SessionPrefs.setProotNoSeccomp(this, on); prootNoSeccomp = on },
             onProotFastPath = { on -> SessionPrefs.setProotFastPath(this, on); prootFastPath = on },
+            onCursorComposite = { on -> SessionPrefs.setCursorComposite(this, on); cursorComposite = on },
             onGuestHostname = { name -> SessionPrefs.setGuestHostname(this, name) },
             onClientCore = { core, on ->
                 clientCores = if (on) clientCores + core else clientCores - core
@@ -1967,6 +1970,7 @@ class FrontEndActivity : ComponentActivity() {
         gpuClockPin = SessionPrefs.gpuClockPin(this)
         prootNoSeccomp = SessionPrefs.prootNoSeccomp(this)
         prootFastPath = SessionPrefs.prootFastPath(this)
+        cursorComposite = SessionPrefs.cursorComposite(this)
         guestHostname = SessionPrefs.guestHostname(this)
         refreshPhantomStatus()
     }

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

@@ -472,6 +472,13 @@ object SessionPrefs {
         prefs(context).edit().putBoolean("prootFastPath", on).apply()
     }
 
+    /** gamescope draws the cursor itself. Off by default: on a phone that plane costs frames. */
+    fun cursorComposite(context: Context): Boolean = prefs(context).getBoolean("cursorComposite", false)
+
+    fun setCursorComposite(context: Context, on: Boolean) {
+        prefs(context).edit().putBoolean("cursorComposite", on).apply()
+    }
+
     const val DEFAULT_GUEST_HOSTNAME = "DroidDeck"
 
     @JvmStatic

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

@@ -720,6 +720,7 @@ class SessionService : Service() {
         guest.add("BL_SYNC_FALLBACK=" + (if (SessionPrefs.syncFallback(this)) "1" else "0"))
         guest.add("BL_FSYNC_FIRST=" + (if (SessionPrefs.fsyncFirst(this)) "1" else "0"))
         guest.add("BL_GAMESCOPE_REALTIME=" + (if (SessionPrefs.gamescopeRealtime(this)) "1" else "0"))
+        if (SessionPrefs.cursorComposite(this)) guest.add("BL_CURSOR_COMPOSITE=1")
         if (com.droiddeck.launcher.core.ZramSupport.supported()) guest.add("BL_ZRAM=1")
         guest.add("BANNER_AUDIO_DIRECT_DECAY=0")
         val extra = extraEnv() + com.droiddeck.launcher.agent.AgentEnv.beginSession(this)

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

@@ -20,7 +20,7 @@ object SettingsReset {
         "gpuDriverMode", "androidDriver", "linuxDriver", "linuxDriver.steam", "linuxDriver.desktop",
         "tuSysmem", "glThread", "noGlError", "zinkLazy", "mangoapp", "gpuClockPin", "gamescopeRealtime",
         "directAudio", "mic", "wifiDiscovery", "clientCpusOverride", "clientCpus", "gameCpus",
-        "noXalia", "fastSync", "fsyncFirst", "syncFallback", "prootNoSeccomp", "prootFastPath",
+        "noXalia", "fastSync", "fsyncFirst", "syncFallback", "prootNoSeccomp", "prootFastPath", "cursorComposite",
         "guestHostname", "fexPreset", "forceSsbs", "logs", "storageDiagnostics",
         "upscaler", "upscaleSharpness", "screenEffects", "textureAnisotropy", "textureLodBias",
         "steamDownloadsInBackground", "steam_offline", "bootMovie", "bootMovieSound", "bootMovieVolume", "bootMovieSeconds",

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

@@ -46,6 +46,7 @@ fun PerformancePage(
     gpuClockPin: Boolean,
     prootNoSeccomp: Boolean,
     prootFastPath: Boolean,
+    cursorComposite: Boolean,
     guestHostname: String,
     phantomWarning: String?,
     onClientOverride: (Boolean) -> Unit,
@@ -61,6 +62,7 @@ fun PerformancePage(
     onGpuClockPin: (Boolean) -> Unit,
     onProotNoSeccomp: (Boolean) -> Unit,
     onProotFastPath: (Boolean) -> Unit,
+    onCursorComposite: (Boolean) -> Unit,
     onGuestHostname: (String) -> Unit,
     onClientCore: (Int, Boolean) -> Unit,
     onGameCore: (Int, Boolean) -> Unit,
@@ -158,6 +160,11 @@ fun PerformancePage(
                 else stringResource(R.string.perf_fastpath_hint),
                 prootFastPath && !prootNoSeccomp, enabled = !prootNoSeccomp, onChange = onProotFastPath,
             )
+            ToggleRow(
+                host, "cursorcomposite", stringResource(R.string.perf_cursor_composite),
+                stringResource(R.string.perf_cursor_composite_hint),
+                cursorComposite, onChange = onCursorComposite,
+            )
         }
         SettingsGroup(stringResource(R.string.perf_identity)) {
             var draft by remember(guestHostname) { mutableStateOf(guestHostname) }

app/src/main/res/values/strings.xml

@@ -568,6 +568,8 @@
     <string name="perf_fastpath">proot fast path</string>
     <string name="perf_fastpath_needs_seccomp">Needs proot\'s seccomp filter.</string>
     <string name="perf_fastpath_hint">Faster file lookups and less stutter. Turn off if a program can\'t find its files.</string>
+    <string name="perf_cursor_composite">Draw the cursor inside gamescope</string>
+    <string name="perf_cursor_composite_hint">Gamescope paints the pointer itself instead of handing it to Android. Turn on for a controller-driven cursor. Off is faster on a phone. Applies next session.</string>
     <string name="perf_identity">Session identity</string>
     <string name="perf_hostname">Host name</string>
     <string name="perf_hostname_hint">The name Steam sees for this device. Blank restores %1$s.</string>

tools/linuxfs/overlay/usr/local/bin/droiddeck-session

@@ -227,7 +227,9 @@ if [ -z "${BL_INSIDE:-}" ]; then
       echo "== gamescope: games at ${nested}x${height} stretched to the ${width}x${height} output"
     fi
   fi
-  if [ "$mode" = steam ]; then
+  # Off unless Performance asks for it. Compositing the cursor here adds a second
+  # plane on the phone's compositor; a controller-driven cursor is the reason to turn it on.
+  if [ "$mode" = steam ] && [ "${BL_CURSOR_COMPOSITE:-0}" = 1 ]; then
     export gamescope_cursor_composite=2
   fi
   args=(--backend wayland --expose-wayland -f -W "$width" -H "$height" -w "$nested" -h "$height")

tools/tests/test_session_cursor_routing.py

@@ -1,4 +1,4 @@
-"""The XTest cursor path is enabled only for Steam sessions."""
+"""Gamescope composites the cursor only when a Steam session asks for it."""
 import os
 from pathlib import Path
 import re
@@ -8,29 +8,37 @@ import unittest
 SESSION = Path(__file__).resolve().parents[1] / 'linuxfs/overlay/usr/local/bin/droiddeck-session'
 SOURCE = SESSION.read_text()
 MATCH = re.search(
-    r'^  if \[ "\$mode" = steam \]; then\n.*?^  fi\n', SOURCE, re.M | re.S)
+    r'^  if \[ "\$mode" = steam \] && \[ "\$\{BL_CURSOR_COMPOSITE:-0\}" = 1 \]; then\n.*?^  fi\n',
+    SOURCE, re.M | re.S)
 assert MATCH is not None
 CURSOR_SETUP = MATCH.group(0)
 
 
 class SessionCursorRoutingTest(unittest.TestCase):
-    def run_setup(self, mode, initial=None):
+    def run_setup(self, mode, initial=None, composite=None):
         env = dict(os.environ, mode=mode)
         if initial is not None:
             env['gamescope_cursor_composite'] = initial
         else:
             env.pop('gamescope_cursor_composite', None)
+        if composite is not None:
+            env['BL_CURSOR_COMPOSITE'] = composite
+        else:
+            env.pop('BL_CURSOR_COMPOSITE', None)
         result = subprocess.run(
             ['bash', '-c', CURSOR_SETUP + 'printf "%s\n" "${gamescope_cursor_composite-}"'],
             env=env, text=True, capture_output=True, check=True)
         return result.stdout.strip()
 
-    def test_steam_enables_manual_composition_for_the_nested_cursor(self):
-        self.assertEqual('2', self.run_setup('steam'))
+    def test_steam_leaves_the_cursor_with_the_host_unless_asked(self):
+        self.assertEqual('', self.run_setup('steam'))
+
+    def test_steam_composites_the_cursor_when_the_setting_is_on(self):
+        self.assertEqual('2', self.run_setup('steam', composite='1'))
 
     def test_other_sessions_keep_their_existing_cursor_composition(self):
-        self.assertEqual('', self.run_setup('desktop'))
-        self.assertEqual('1', self.run_setup('run', '1'))
+        self.assertEqual('', self.run_setup('desktop', composite='1'))
+        self.assertEqual('1', self.run_setup('run', '1', composite='1'))
 
 
 if __name__ == '__main__':