added fps counter

android/app/src/main/cpp/xemu_snapshots_stub.c

@@ -387,8 +387,44 @@ static struct {
     .cond = PTHREAD_COND_INITIALIZER,
 };
 
+static struct {
+    pthread_mutex_t lock;
+    uint64_t window_start_ms;
+    uint64_t last_frame_ms;
+    uint32_t frame_count;
+    float fps;
+} g_fps_state = {
+    .lock = PTHREAD_MUTEX_INITIALIZER,
+};
+
+static void update_android_fps_counter(void)
+{
+    const uint64_t now_ms = (uint64_t)SDL_GetTicks64();
+
+    pthread_mutex_lock(&g_fps_state.lock);
+
+    if (g_fps_state.window_start_ms == 0) {
+        g_fps_state.window_start_ms = now_ms;
+    }
+
+    g_fps_state.last_frame_ms = now_ms;
+    g_fps_state.frame_count++;
+
+    const uint64_t elapsed_ms = now_ms - g_fps_state.window_start_ms;
+    if (elapsed_ms >= 500) {
+        g_fps_state.fps = ((float)g_fps_state.frame_count * 1000.0f) /
+                          (float)elapsed_ms;
+        g_fps_state.frame_count = 0;
+        g_fps_state.window_start_ms = now_ms;
+    }
+
+    pthread_mutex_unlock(&g_fps_state.lock);
+}
+
 void xemu_android_process_snapshot_request(void)
 {
+    update_android_fps_counter();
+
     if (pthread_mutex_trylock(&g_snap_req.lock) != 0) {
         return;
     }
@@ -460,3 +496,27 @@ Java_com_izzy2lost_x1box_MainActivity_nativeLoadSnapshot(
     (void)obj;
     return dispatch_snapshot(env, name, SNAP_LOAD);
 }
+
+JNIEXPORT jfloat JNICALL
+Java_com_izzy2lost_x1box_MainActivity_nativeGetFps(
+        JNIEnv *env, jobject obj)
+{
+    float fps = 0.0f;
+    const uint64_t now_ms = (uint64_t)SDL_GetTicks64();
+    (void)env;
+    (void)obj;
+
+    pthread_mutex_lock(&g_fps_state.lock);
+    fps = g_fps_state.fps;
+    if (g_fps_state.last_frame_ms == 0 ||
+        (now_ms - g_fps_state.last_frame_ms) > 1500) {
+        fps = 0.0f;
+    }
+    pthread_mutex_unlock(&g_fps_state.lock);
+
+    if (fps < 0.0f) {
+        fps = 0.0f;
+    }
+
+    return (jfloat)fps;
+}

android/app/src/main/java/com/izzy2lost/x1box/MainActivity.kt

@@ -3,10 +3,16 @@ package com.izzy2lost.x1box
 import android.content.Context
 import android.content.Intent
 import android.graphics.Bitmap
+import android.graphics.Color
+import android.graphics.Typeface
 import android.hardware.input.InputManager
 import android.net.Uri
 import android.os.Build
 import android.os.Bundle
+import android.os.Handler
+import android.os.Looper
+import android.util.TypedValue
+import android.view.Gravity
 import android.view.InputDevice
 import android.view.KeyEvent
 import android.view.View
@@ -17,6 +23,7 @@ import android.widget.BaseAdapter
 import android.widget.FrameLayout
 import android.widget.ImageView
 import android.widget.ListView
+import android.widget.RelativeLayout
 import android.widget.TextView
 import android.widget.Toast
 import androidx.appcompat.app.AlertDialog
@@ -25,12 +32,14 @@ import org.libsdl.app.SDLActivity
 import java.io.File
 import java.nio.ByteBuffer
 import java.nio.ByteOrder
+import java.util.Locale
 
 class MainActivity : SDLActivity(), InputManager.InputDeviceListener {
   companion object {
     const val EXTRA_AUTO_LOAD_SNAPSHOT_SLOT = "com.izzy2lost.x1box.extra.AUTO_LOAD_SNAPSHOT_SLOT"
     private const val SNAPSHOT_PREVIEW_HEADER_SIZE = 12
     private const val TOTAL_SNAPSHOT_SLOTS = 10
+    private const val PREF_SHOW_FPS_COUNTER = "setting_show_fps_counter"
   }
 
   private data class SnapshotSlotPreview(
@@ -51,6 +60,17 @@ class MainActivity : SDLActivity(), InputManager.InputDeviceListener {
   private var comboTriggered = false
   private var startupSnapshotSlot: Int? = null
   private var startupSnapshotLoadScheduled = false
+  private var showFpsCounter = false
+  private var fpsCounterView: TextView? = null
+  private val fpsUpdateHandler = Handler(Looper.getMainLooper())
+  private val fpsUpdateRunnable = object : Runnable {
+    override fun run() {
+      val view = fpsCounterView ?: return
+      val fps = nativeGetFps().coerceAtLeast(0f)
+      view.text = String.format(Locale.US, "FPS %.1f", fps)
+      fpsUpdateHandler.postDelayed(this, 500L)
+    }
+  }
 
   override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
@@ -58,7 +78,11 @@ class MainActivity : SDLActivity(), InputManager.InputDeviceListener {
     if (requestedSlot in 1..TOTAL_SNAPSHOT_SLOTS) {
       startupSnapshotSlot = requestedSlot
     }
+    showFpsCounter = isFpsCounterEnabled()
     setupOnScreenController()
+    if (showFpsCounter) {
+      setupFpsCounter()
+    }
     setupControllerDetection()
     hideSystemUI()
   }
@@ -141,6 +165,107 @@ class MainActivity : SDLActivity(), InputManager.InputDeviceListener {
     updateControllerVisibility()
   }
 
+  private fun dpToPx(dp: Int): Int = (dp * resources.displayMetrics.density).toInt()
+
+  private fun isFpsCounterEnabled(): Boolean {
+    return getSharedPreferences("x1box_prefs", MODE_PRIVATE)
+      .getBoolean(PREF_SHOW_FPS_COUNTER, false)
+  }
+
+  private fun applyFpsCounterPreference() {
+    val shouldShow = isFpsCounterEnabled()
+    if (shouldShow == showFpsCounter) {
+      if (showFpsCounter && fpsCounterView == null) {
+        setupFpsCounter()
+      }
+      return
+    }
+
+    showFpsCounter = shouldShow
+    if (showFpsCounter) {
+      setupFpsCounter()
+      startFpsUpdates()
+    } else {
+      stopFpsUpdates()
+      fpsCounterView?.let { view ->
+        (view.parent as? ViewGroup)?.removeView(view)
+      }
+      fpsCounterView = null
+    }
+  }
+
+  private fun setupFpsCounter() {
+    if (fpsCounterView != null) {
+      return
+    }
+
+    val parent = mLayout ?: return
+    val baseTopMargin = dpToPx(12)
+    val counter = TextView(this).apply {
+      text = "FPS 0.0"
+      setTextColor(Color.WHITE)
+      setTypeface(Typeface.MONOSPACE, Typeface.BOLD)
+      setTextSize(TypedValue.COMPLEX_UNIT_SP, 12f)
+      setPadding(dpToPx(10), dpToPx(4), dpToPx(10), dpToPx(4))
+      setBackgroundColor(Color.argb(150, 0, 0, 0))
+      isClickable = false
+      isFocusable = false
+      importantForAccessibility = View.IMPORTANT_FOR_ACCESSIBILITY_NO
+    }
+
+    counter.layoutParams = if (parent is RelativeLayout) {
+      RelativeLayout.LayoutParams(
+        RelativeLayout.LayoutParams.WRAP_CONTENT,
+        RelativeLayout.LayoutParams.WRAP_CONTENT
+      ).apply {
+        addRule(RelativeLayout.ALIGN_PARENT_TOP)
+        addRule(RelativeLayout.CENTER_HORIZONTAL)
+        topMargin = baseTopMargin
+      }
+    } else {
+      FrameLayout.LayoutParams(
+        FrameLayout.LayoutParams.WRAP_CONTENT,
+        FrameLayout.LayoutParams.WRAP_CONTENT
+      ).apply {
+        gravity = Gravity.TOP or Gravity.CENTER_HORIZONTAL
+        topMargin = baseTopMargin
+      }
+    }
+
+    counter.setOnApplyWindowInsetsListener { view, insets ->
+      val topInset = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
+        insets.getInsets(WindowInsets.Type.statusBars() or WindowInsets.Type.displayCutout()).top
+      } else {
+        @Suppress("DEPRECATION")
+        insets.systemWindowInsetTop
+      }
+
+      val layoutParams = view.layoutParams
+      if (layoutParams is ViewGroup.MarginLayoutParams) {
+        val wantedTopMargin = baseTopMargin + topInset
+        if (layoutParams.topMargin != wantedTopMargin) {
+          layoutParams.topMargin = wantedTopMargin
+          view.layoutParams = layoutParams
+        }
+      }
+      insets
+    }
+
+    fpsCounterView = counter
+    parent.addView(counter)
+    counter.bringToFront()
+    counter.requestApplyInsets()
+  }
+
+  private fun startFpsUpdates() {
+    fpsUpdateHandler.removeCallbacks(fpsUpdateRunnable)
+    fpsUpdateRunnable.run()
+  }
+
+  private fun stopFpsUpdates() {
+    fpsUpdateHandler.removeCallbacks(fpsUpdateRunnable)
+  }
+
   override fun onResume() {
     super.onResume()
     
@@ -150,7 +275,16 @@ class MainActivity : SDLActivity(), InputManager.InputDeviceListener {
       registerVirtualController()
     }, 1000)
 
+    applyFpsCounterPreference()
     scheduleStartupSnapshotLoadIfRequested()
+    if (showFpsCounter) {
+      startFpsUpdates()
+    }
+  }
+
+  override fun onPause() {
+    stopFpsUpdates()
+    super.onPause()
   }
 
   private fun scheduleStartupSnapshotLoadIfRequested() {
@@ -260,6 +394,7 @@ class MainActivity : SDLActivity(), InputManager.InputDeviceListener {
   }
 
   override fun onDestroy() {
+    stopFpsUpdates()
     inGameMenuDialog?.dismiss()
     inGameMenuDialog = null
 
@@ -271,6 +406,7 @@ class MainActivity : SDLActivity(), InputManager.InputDeviceListener {
     }
     
     inputManager?.unregisterInputDeviceListener(this)
+    fpsCounterView = null
     super.onDestroy()
   }
 
@@ -346,6 +482,7 @@ class MainActivity : SDLActivity(), InputManager.InputDeviceListener {
 
   private external fun nativeSaveSnapshot(name: String): Boolean
   private external fun nativeLoadSnapshot(name: String): Boolean
+  private external fun nativeGetFps(): Float
 
   private fun slotName(slot: Int) = "android_slot_$slot"
 

android/app/src/main/java/com/izzy2lost/x1box/SettingsActivity.kt

@@ -47,6 +47,7 @@ class SettingsActivity : AppCompatActivity() {
     val switchHrtf        = findViewById<MaterialSwitch>(R.id.switch_hrtf)
     val switchShaders     = findViewById<MaterialSwitch>(R.id.switch_cache_shaders)
     val switchFpu         = findViewById<MaterialSwitch>(R.id.switch_hard_fpu)
+    val switchShowFps     = findViewById<MaterialSwitch>(R.id.switch_show_fps_counter)
     val toggleAudioDriver = findViewById<MaterialButtonToggleGroup>(R.id.toggle_audio_driver)
     val btnSave           = findViewById<MaterialButton>(R.id.btn_settings_save)
     tvVulkanDriverName    = findViewById(R.id.tv_vulkan_driver_name)
@@ -83,6 +84,7 @@ class SettingsActivity : AppCompatActivity() {
     switchHrtf.isChecked    = prefs.getBoolean("setting_hrtf", true)
     switchShaders.isChecked = prefs.getBoolean("setting_cache_shaders", true)
     switchFpu.isChecked     = prefs.getBoolean("setting_hard_fpu", true)
+    switchShowFps.isChecked = prefs.getBoolean("setting_show_fps_counter", false)
 
     val audioDriver = prefs.getString("setting_audio_driver", "openslES") ?: "openslES"
     when (audioDriver) {
@@ -131,6 +133,7 @@ class SettingsActivity : AppCompatActivity() {
         .putBoolean("setting_hrtf", switchHrtf.isChecked)
         .putBoolean("setting_cache_shaders", switchShaders.isChecked)
         .putBoolean("setting_hard_fpu", switchFpu.isChecked)
+        .putBoolean("setting_show_fps_counter", switchShowFps.isChecked)
         .putString("setting_audio_driver", selectedAudioDriver)
 
       when {

android/app/src/main/res/layout/activity_settings.xml

@@ -140,6 +140,14 @@
 
           </com.google.android.material.button.MaterialButtonToggleGroup>
 
+          <com.google.android.material.materialswitch.MaterialSwitch
+            android:id="@+id/switch_show_fps_counter"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="4dp"
+            android:text="@string/settings_show_fps_counter"
+            android:textColor="@color/xemu_text_muted" />
+
           <!-- ── VULKAN DRIVER ── -->
           <TextView
             android:layout_width="match_parent"

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

@@ -89,6 +89,7 @@
   <string name="settings_display_mode_stretch">Stretch</string>
   <string name="settings_display_mode_4_3">4:3</string>
   <string name="settings_display_mode_16_9">16:9</string>
+  <string name="settings_show_fps_counter">Show FPS Counter</string>
 
   <string name="settings_resolution_scale">Internal Resolution Scale</string>
   <string name="settings_resolution_scale_1x">1x (Native 480p)</string>