Implement speed limit option (#51)

app/src/main/cpp/skyline/common/android_settings.h

@@ -31,6 +31,8 @@ namespace skyline {
         }
 
         void Update() override {
+            enableSpeedLimit = ktSettings.GetBool("enableSpeedLimit");
+            speedLimit = ktSettings.GetFloat("speedLimit");
             isDocked = ktSettings.GetBool("isDocked");
             usernameValue = std::move(ktSettings.GetString("usernameValue"));
             profilePictureValue = ktSettings.GetString("profilePictureValue");

app/src/main/cpp/skyline/common/settings.h

@@ -61,6 +61,8 @@ namespace skyline {
 
       public:
         // System
+        Setting<bool> enableSpeedLimit;
+        Setting<float> speedLimit;
         Setting<bool> isDocked; //!< If the emulated Switch should be handheld or docked
         Setting<std::string> usernameValue; //!< The user name to be supplied to the guest
         Setting<std::string> profilePictureValue; //!< The profile picture path to be supplied to the guest

app/src/main/cpp/skyline/gpu/presentation_engine.cpp

@@ -238,6 +238,7 @@ namespace skyline::gpu {
         } else {
             frameTimestamp = timestamp;
         }
+        if (*state.settings->enableSpeedLimit) LimitSpeed(constant::NsInSecond / 60);
     }
 
     void PresentationEngine::PresentationThread() {
@@ -448,6 +449,23 @@ namespace skyline::gpu {
         return nextFrameId++;
     }
 
+    void PresentationEngine::LimitSpeed(i64 targetFrameTimeNs) {
+        static i64 lastFrameTime = 0;
+        i64 currentTime = util::GetTimeNs();
+
+        i64 adjustedFrameTimeNs = static_cast<i64>(targetFrameTimeNs / (*state.settings->speedLimit / 100.0f));
+
+        if (lastFrameTime != 0) {
+            i64 elapsedTime = currentTime - lastFrameTime;
+            if (elapsedTime < adjustedFrameTimeNs) {
+                // Sleep for the remaining time to meet the adjusted frame time
+                std::this_thread::sleep_for(std::chrono::nanoseconds(adjustedFrameTimeNs - elapsedTime));
+            }
+        }
+
+        lastFrameTime = util::GetTimeNs(); // Update last frame time
+    }
+
     void PresentationEngine::Pause() {
         paused.store(true, std::memory_order_release);
         LOGI("PresentationEngine paused.");

app/src/main/cpp/skyline/gpu/presentation_engine.h

@@ -105,6 +105,8 @@ namespace skyline::gpu {
          */
         void UpdateSwapchain(texture::Format format, texture::Dimensions extent);
 
+        void LimitSpeed(i64 targetFrameTimeNs);
+
       public:
         PresentationEngine(const DeviceState &state, GPU &gpu);
 

app/src/main/cpp/skyline/jvm.h

@@ -68,6 +68,10 @@ namespace skyline {
         JniString GetString(const std::string_view &key) {
             return {env, static_cast<jstring>(env->GetObjectField(settingsInstance, env->GetFieldID(settingsClass, key.data(), "Ljava/lang/String;")))};
         }
+
+        float GetFloat(const std::string_view &key) {
+            return static_cast<float>(env->GetFloatField(settingsInstance, env->GetFieldID(settingsClass, key.data(), "F")));
+        }
     };
 
     /**

app/src/main/java/emu/skyline/preference/SeekBarPreference.kt

@@ -2,7 +2,9 @@
 package emu.skyline.preference
 
 import android.content.Context
+import android.content.res.TypedArray
 import android.util.AttributeSet
+import android.util.Log
 import android.view.LayoutInflater
 import android.view.View
 import androidx.preference.DialogPreference
@@ -35,13 +37,17 @@ class SeekBarPreference(context: Context, attrs: AttributeSet) : DialogPreferenc
         }
     }
 
+    override fun onGetDefaultValue(a: TypedArray, index: Int): Any {
+        return a.getInt(index, 0)
+    }
+
     override fun onClick() { showMaterialDialog() }
 
     private fun showMaterialDialog() {
         val dialogView = LayoutInflater.from(context).inflate(R.layout.preference_dialog_seekbar, null)
         val slider = dialogView.findViewById<Slider>(R.id.seekBar)
         val valueText = dialogView.findViewById<MaterialTextView>(R.id.value)
-
+        
         // Configure slider
         slider.valueFrom = if (isPercentage) minValue.toFloat() else minValue.toInt().toFloat()
         slider.valueTo = if (isPercentage) maxValue.toFloat() else maxValue.toInt().toFloat()
@@ -56,11 +62,14 @@ class SeekBarPreference(context: Context, attrs: AttributeSet) : DialogPreferenc
             currentValue = if (isPercentage) value else value.toInt()
         }
 
+        var dismissTrigger: String? = null
+
         // Build and show the MaterialAlertDialog
         MaterialAlertDialogBuilder(context)
             .setTitle(title)
             .setView(dialogView)
             .setPositiveButton(android.R.string.ok) { _, _ ->
+                dismissTrigger = "positive_button"
                 if (isPercentage) {
                     persistFloat(currentValue.toFloat())
                 } else {
@@ -69,8 +78,10 @@ class SeekBarPreference(context: Context, attrs: AttributeSet) : DialogPreferenc
                 updateSummary()
                 callChangeListener(currentValue)
             }
-            .setNegativeButton(android.R.string.cancel) { _, _ ->
-                slider.value = summary.toString().replace("%", "").toInt().toFloat()
+            .setNegativeButton(android.R.string.cancel, null)
+            .setOnDismissListener {
+                if (dismissTrigger != "positive_button")
+                    slider.value = summary?.toString()?.replace("%", "")?.toIntOrNull()?.toFloat() ?: minValue.toFloat()
             }
             .show()
     }
@@ -92,11 +103,21 @@ class SeekBarPreference(context: Context, attrs: AttributeSet) : DialogPreferenc
     }
 
     override fun onSetInitialValue(defaultValue: Any?) {
-        currentValue = if (isPercentage) {
-            getPersistedFloat((defaultValue as? Float) ?: minValue.toFloat()).toFloat()
-        } else {
-            getPersistedInt((defaultValue as? Int) ?: minValue.toInt())
+        val actualDefaultValue = when (defaultValue) {
+            is String -> defaultValue.toIntOrNull() ?: minValue.toInt()
+            is Int -> defaultValue ?: minValue.toInt()
+            is Float -> defaultValue.toInt()
+            else -> minValue.toInt() // fallback to minValue if default is invalid
         }
+        currentValue = if (!isPercentage) getPersistedInt(actualDefaultValue!!)!! else getPersistedFloat(actualDefaultValue.toFloat()!!).toInt()!!
         updateSummary()
     }
+
+    fun setMaxValue(max: Any) { 
+        if (isPercentage) maxValue = max as Float else maxValue = max as Int
+    }
+
+    fun setMinValue(min: Any) {
+        if (isPercentage) minValue = min as Float else minValue = min as Int
+    }
 }

app/src/main/java/emu/skyline/settings/EmulationSettings.kt

@@ -24,6 +24,8 @@ class EmulationSettings private constructor(context : Context, prefName : String
     var useCustomSettings by sharedPreferences(context, false, prefName = prefName)
 
     // System
+    var enableSpeedLimit by sharedPreferences(context, false, prefName = prefName)
+    var speedLimit by sharedPreferences(context, 100f, prefName = prefName)
     var isDocked by sharedPreferences(context, true, prefName = prefName)
     var usernameValue by sharedPreferences(context, context.getString(R.string.username_default), prefName = prefName)
     var profilePictureValue by sharedPreferences(context, "", prefName = prefName)

app/src/main/java/emu/skyline/settings/GameSettingsFragment.kt

@@ -50,20 +50,23 @@ class GameSettingsFragment : PreferenceFragmentCompat() {
             findPreference("category_debug")
         ).forEach { it?.dependency = "use_custom_settings" }
 
+        findPreference<Preference>("enable_speed_limit")?.setOnPreferenceChangeListener { _, newValue ->
+            disablePreference("speed_limit", !(newValue as Boolean), null)
+            true
+        }
+
         // Only show validation layer setting in debug builds
         @Suppress("SENSELESS_COMPARISON")
         if (BuildConfig.BUILD_TYPE != "release")
             findPreference<Preference>("validation_layer")?.isVisible = true
 
-        if (!GpuDriverHelper.supportsForceMaxGpuClocks()) {
-            val forceMaxGpuClocksPref = findPreference<TwoStatePreference>("force_max_gpu_clocks")!!
-            forceMaxGpuClocksPref.isSelectable = false
-            forceMaxGpuClocksPref.isChecked = false
-            forceMaxGpuClocksPref.summary = context!!.getString(R.string.force_max_gpu_clocks_desc_unsupported)
-        }
-
         findPreference<GpuDriverPreference>("gpu_driver")?.item = item
 
+        findPreference<SwitchPreferenceCompat>("enable_speed_limit")?.isChecked?.let {
+            disablePreference("speed_limit", !it, null)
+        }
+        disablePreference("force_max_gpu_clocks", !GpuDriverHelper.supportsForceMaxGpuClocks(), context?.getString(R.string.force_max_gpu_clocks_desc_unsupported))
+
         // Hide settings that don't support per-game configuration
         var prefToRemove = findPreference<Preference>("profile_picture_value")
         prefToRemove?.parent?.removePreference(prefToRemove)
@@ -76,4 +79,20 @@ class GameSettingsFragment : PreferenceFragmentCompat() {
         if (BuildConfig.BUILD_TYPE == "release")
             findPreference<PreferenceCategory>("category_debug")?.isVisible = false
     }
+
+    private fun disablePreference(
+        preferenceId: String, 
+        isDisabled: Boolean, 
+        disabledSummary: String? = null
+    ) {
+        val preference = findPreference<Preference>(preferenceId)!!
+        preference.isSelectable = !isDisabled
+        preference.isEnabled = !isDisabled
+        if (preference is TwoStatePreference && isDisabled) {
+            preference.isChecked = false
+        }
+        if (isDisabled && disabledSummary != null) {
+            preference.summary = disabledSummary
+        }
+    }
 }

app/src/main/java/emu/skyline/settings/GlobalSettingsFragment.kt

@@ -53,6 +53,11 @@ class GlobalSettingsFragment : PreferenceFragmentCompat() {
             true
         }
 
+        findPreference<Preference>("enable_speed_limit")?.setOnPreferenceChangeListener { _, newValue ->
+            disablePreference("speed_limit", !(newValue as Boolean), null)
+            true
+        }
+
         CoroutineScope(Dispatchers.IO).launch {
             WindowInfoTracker.getOrCreate(requireContext()).windowLayoutInfo(requireActivity()).collect { newLayoutInfo ->
                 withContext(Dispatchers.Main) {
@@ -68,6 +73,9 @@ class GlobalSettingsFragment : PreferenceFragmentCompat() {
 
         disablePreference("use_material_you", Build.VERSION.SDK_INT < Build.VERSION_CODES.S, null)
         disablePreference("force_max_gpu_clocks", !GpuDriverHelper.supportsForceMaxGpuClocks(), context!!.getString(R.string.force_max_gpu_clocks_desc_unsupported))
+        findPreference<SwitchPreferenceCompat>("enable_speed_limit")?.isChecked?.let {
+            disablePreference("speed_limit", !it, null)
+        }
         resources.getStringArray(R.array.credits_entries).asIterable().shuffled().forEach {
             findPreference<PreferenceCategory>("category_credits")?.addPreference(Preference(context!!).apply {
                 title = it

app/src/main/java/emu/skyline/settings/NativeSettings.kt

@@ -17,6 +17,8 @@ import kotlinx.serialization.Serializable
 @Suppress("unused")
 data class NativeSettings(
     // System
+    var enableSpeedLimit : Boolean,
+    var speedLimit : Float,
     var isDocked : Boolean,
     var usernameValue : String,
     var profilePictureValue : String,
@@ -50,6 +52,8 @@ data class NativeSettings(
     var validationLayer : Boolean
 ) {
     constructor(context : Context, pref : EmulationSettings) : this(
+        pref.enableSpeedLimit,
+        pref.speedLimit,
         pref.isDocked,
         pref.usernameValue,
         pref.profilePictureValue,

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

@@ -97,6 +97,10 @@
     <string name="copy_global_settings_warning">Are you sure you want to copy global settings to this game? <b>Current settings will be lost</b></string>
     <!-- Settings - System -->
     <string name="system">System</string>
+    <string name="enable_speed_limit">Enable Speed Limit</string>
+    <string name="enable_speed_limit_desc">Emulation speed will be limited</string>
+    <string name="speed_limit">Speed Limit</string>
+    <string name="speed_limit_desc">Set the emulation speed limit</string>
     <string name="use_docked">Use Docked Mode</string>
     <string name="handheld_enabled">The system will emulate being in handheld mode</string>
     <string name="docked_enabled">The system will emulate being in docked mode</string>

app/src/main/res/xml/emulation_preferences.xml

@@ -3,6 +3,19 @@
     <PreferenceCategory
         android:key="category_system"
         android:title="@string/system">
+        <SwitchPreferenceCompat
+            android:defaultValue="false"
+            android:summary="@string/enable_speed_limit_desc"
+            app:key="enable_speed_limit"
+            app:title="@string/enable_speed_limit" />
+        <emu.skyline.preference.SeekBarPreference
+            android:summary="@string/speed_limit_desc"
+            android:defaultValue="100"
+            android:key="speed_limit"
+            android:title="@string/speed_limit" 
+            app:maxValue="200"
+            app:minValue="0"
+            app:isPercentage="true" />
         <SwitchPreferenceCompat
             android:defaultValue="true"
             android:summaryOff="@string/handheld_enabled"
@@ -148,16 +161,16 @@
             app:title="@string/vsync_mode"
             app:useSimpleSummaryProvider="true"/>
         <emu.skyline.preference.SeekBarPreference
-            android:defaultValue="4"
             android:summary="@string/executor_slot_count_scale_desc"
+            android:defaultValue="4"
             android:key="executor_slot_count_scale"
             android:title="@string/executor_slot_count_scale" 
             app:maxValue="6"
             app:minValue="1"
             app:isPercentage="false" />
         <emu.skyline.preference.SeekBarPreference
-            android:defaultValue="256"
             android:summary="@string/executor_flush_threshold_desc"
+            android:defaultValue="256"
             android:key="executor_flush_threshold"
             android:title="@string/executor_flush_threshold" 
             app:maxValue="1024"