Android: Dual core warning when hosting netplay

Using dual core during netplay seems sufficiently detrimental that its worth showing this warning message and the option to turn dual core off when starting netplay.

Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/netplay/model/NetplayViewModel.kt

@@ -11,15 +11,16 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.channels.Channel
 import kotlinx.coroutines.flow.MutableStateFlow
-import kotlinx.coroutines.flow.receiveAsFlow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.flow.receiveAsFlow
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
 import org.dolphinemu.dolphinemu.features.netplay.NetplaySession
+import org.dolphinemu.dolphinemu.features.settings.model.BooleanSetting
 import org.dolphinemu.dolphinemu.features.settings.model.IntSetting
 import org.dolphinemu.dolphinemu.features.settings.model.NativeConfig
 import org.dolphinemu.dolphinemu.features.settings.model.StringSetting
@@ -104,18 +105,37 @@ class NetplayViewModel(
     private val _notAllPlayersHaveGame = Channel<Unit>(Channel.CONFLATED)
     val notAllPlayersHaveGame = _notAllPlayersHaveGame.receiveAsFlow()
 
+    private val _dualCoreWarning = Channel<Unit>(Channel.CONFLATED)
+    val dualCoreWarning = _dualCoreWarning.receiveAsFlow()
+
     fun startGame() {
-        if (netplaySession.doAllPlayersHaveGame()) {
-            netplaySession.startGame()
-        } else {
+        if (!netplaySession.doAllPlayersHaveGame()) {
             _notAllPlayersHaveGame.trySend(Unit)
+            return
         }
+
+        if (BooleanSetting.MAIN_CPU_THREAD.boolean &&
+            !BooleanSetting.NETPLAY_SKIP_DUAL_CORE_WARNING.boolean
+        ) {
+            _dualCoreWarning.trySend(Unit)
+            return
+        }
+
+        confirmStartGame()
     }
 
     fun confirmStartGame() {
         netplaySession.startGame()
     }
 
+    fun setDualCoreEnabled(enabled: Boolean) {
+        BooleanSetting.MAIN_CPU_THREAD.setBoolean(NativeConfig.LAYER_BASE, enabled)
+    }
+
+    fun skipDualCoreWarning() {
+        BooleanSetting.NETPLAY_SKIP_DUAL_CORE_WARNING.setBoolean(NativeConfig.LAYER_BASE, true)
+    }
+
     fun sendMessage(message: String) {
         val trimmedMessage = message.trim()
         if (trimmedMessage.isEmpty()) {
@@ -176,12 +196,14 @@ class NetplayViewModel(
                         JoinInfoType.EXTERNAL to JoinAddress.Loading,
                     )
                 }
+
                 is TraversalState.Connected -> {
                     _joinAddresses.value += mapOf(
                         JoinInfoType.ROOM_ID to JoinAddress.Loaded(state.hostCode),
                         JoinInfoType.EXTERNAL to JoinAddress.Loaded(state.externalAddress),
                     )
                 }
+
                 is TraversalState.Failure -> {
                     _joinAddresses.value += mapOf(
                         JoinInfoType.ROOM_ID to JoinAddress.Unknown(retry),

Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/netplay/ui/NetplayActivity.kt

@@ -58,6 +58,9 @@ class NetplayActivity : AppCompatActivity(), ThemeProvider {
                     onGameSelected = viewModel::changeGame,
                     gameFiles = viewModel.gameFiles.collectAsState().value,
                     notAllPlayersHaveGame = viewModel.notAllPlayersHaveGame,
+                    dualCoreWarning = viewModel.dualCoreWarning,
+                    onSetDualCoreEnabled = viewModel::setDualCoreEnabled,
+                    onSkipDualCoreWarning = viewModel::skipDualCoreWarning,
                     onConfirmStartGame = viewModel::confirmStartGame,
                     players = viewModel.players.collectAsState().value,
                     hostInputAuthorityEnabled = viewModel.hostInputAuthority.collectAsState().value,

Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/netplay/ui/NetplayScreen.kt

@@ -5,6 +5,7 @@ package org.dolphinemu.dolphinemu.features.netplay.ui
 import android.content.Intent
 import android.content.res.Configuration
 import androidx.compose.foundation.ScrollState
+import androidx.compose.foundation.clickable
 import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
@@ -37,6 +38,7 @@ import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.ArrowBack
 import androidx.compose.material.icons.automirrored.filled.Send
 import androidx.compose.material.icons.filled.Add
+import androidx.compose.material.icons.filled.MoreVert
 import androidx.compose.material.icons.filled.Refresh
 import androidx.compose.material.icons.filled.Remove
 import androidx.compose.material.icons.filled.Share
@@ -59,6 +61,7 @@ import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.ModalBottomSheet
 import androidx.compose.material3.OutlinedTextField
 import androidx.compose.material3.SheetValue
+import androidx.compose.material3.Switch
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
 import androidx.compose.material3.adaptive.currentWindowAdaptiveInfo
@@ -72,7 +75,10 @@ import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.layout.layout
 import androidx.compose.ui.layout.onGloballyPositioned
 import androidx.compose.ui.platform.LocalConfiguration
 import androidx.compose.ui.platform.LocalContext
@@ -87,7 +93,6 @@ import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
-import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.unit.sp
 import androidx.window.core.layout.WindowSizeClass
 import coil.compose.AsyncImage
@@ -129,6 +134,9 @@ fun NetplayScreen(
     onGameSelected: (GameFile) -> Unit,
     gameFiles: List<GameFile>,
     notAllPlayersHaveGame: Flow<Unit>,
+    dualCoreWarning: Flow<Unit>,
+    onSetDualCoreEnabled: (Boolean) -> Unit,
+    onSkipDualCoreWarning: () -> Unit,
     onConfirmStartGame: () -> Unit,
     hostInputAuthorityEnabled: Boolean,
     networkMode: NetworkMode,
@@ -252,6 +260,11 @@ fun NetplayScreen(
             notAllPlayersHaveGame.collect { showNotAllPlayersHaveGame = true }
         }
 
+        var showDualCoreWarning by rememberSaveable { mutableStateOf(false) }
+        LaunchedEffect(Unit) {
+            dualCoreWarning.collect { showDualCoreWarning = true }
+        }
+
         var dismissSaveTransferProgressDialog by rememberSaveable { mutableStateOf(false) }
         if (saveTransferProgress == null) {
             dismissSaveTransferProgressDialog = false
@@ -323,6 +336,21 @@ fun NetplayScreen(
                     onDismissRequest = { showNotAllPlayersHaveGame = false },
                 )
             }
+
+            showDualCoreWarning -> {
+                DualCoreWarningDialog(
+                    onSetDualCoreEnabled = onSetDualCoreEnabled,
+                    onStartGame = {
+                        showDualCoreWarning = false
+                        onConfirmStartGame()
+                    },
+                    onSkipWarning = {
+                        showDualCoreWarning = false
+                        onSkipDualCoreWarning()
+                    },
+                    onDismiss = { showDualCoreWarning = false },
+                )
+            }
         }
     }
 }
@@ -1273,6 +1301,73 @@ private fun GameDigestPlayerRow(
     }
 }
 
+@Composable
+private fun DualCoreWarningDialog(
+    onSetDualCoreEnabled: (Boolean) -> Unit,
+    onStartGame: () -> Unit,
+    onSkipWarning: () -> Unit,
+    onDismiss: () -> Unit,
+) {
+    var dualCoreEnabled by rememberSaveable { mutableStateOf(true) }
+    AlertDialog(
+        title = { Text(stringResource(R.string.netplay_dual_core_warning_title)) },
+        text = {
+            Column {
+                Text(
+                    text = stringResource(R.string.netplay_dual_core_warning_message),
+                )
+                val ripplePadding = 12.dp
+                Spacer(Modifier.height(12.dp))
+                Row(
+                    verticalAlignment = Alignment.CenterVertically,
+                    modifier = Modifier
+                        .fillMaxWidth()
+                        .layout { measurable, constraints ->
+                            // Enlarge the ripple area beyond the dialog's padding
+                            val hPx = ripplePadding.roundToPx()
+                            val placeable = measurable.measure(
+                                constraints.copy(
+                                    minWidth = constraints.maxWidth + hPx * 2,
+                                    maxWidth = constraints.maxWidth + hPx * 2
+                                )
+                            )
+                            layout(constraints.maxWidth, placeable.height) {
+                                placeable.place(-hPx, 0)
+                            }
+                        }
+                        .clip(MaterialTheme.shapes.small)
+                        .clickable {
+                            dualCoreEnabled = !dualCoreEnabled
+                            onSetDualCoreEnabled(dualCoreEnabled)
+                        }
+                        .padding(ripplePadding),
+                ) {
+                    Text(
+                        text = stringResource(R.string.dual_core),
+                        color = MaterialTheme.colorScheme.onSurface,
+                        modifier = Modifier.weight(1f),
+                    )
+                    Switch(
+                        checked = dualCoreEnabled,
+                        onCheckedChange = null,
+                    )
+                }
+            }
+        },
+        confirmButton = {
+            TextButton(onClick = onStartGame) {
+                Text(stringResource(R.string.netplay_start))
+            }
+        },
+        dismissButton = {
+            TextButton(onClick = onSkipWarning) {
+                Text(stringResource(R.string.netplay_dont_warn_again))
+            }
+        },
+        onDismissRequest = onDismiss,
+    )
+}
+
 @Composable
 private fun NetplayMessage.color(): Color {
     val isDark = isSystemInDarkTheme()
@@ -1361,6 +1456,9 @@ private fun PreviewNetplayScreen() {
         onGameSelected = {},
         gameFiles = emptyList(),
         notAllPlayersHaveGame = emptyFlow(),
+        dualCoreWarning = emptyFlow(),
+        onSetDualCoreEnabled = {},
+        onSkipDualCoreWarning = {},
         onConfirmStartGame = {},
         hostInputAuthorityEnabled = true,
         networkMode = NetworkMode.HOST_INPUT_AUTHORITY,

Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/settings/model/BooleanSetting.kt

@@ -947,7 +947,8 @@ enum class BooleanSetting(
         "ProgressEnabled",
         false
     ),
-    NETPLAY_USE_UPNP(Settings.FILE_DOLPHIN, Settings.SECTION_INI_NETPLAY, "UseUPNP", false);
+    NETPLAY_USE_UPNP(Settings.FILE_DOLPHIN, Settings.SECTION_INI_NETPLAY, "UseUPNP", false),
+    NETPLAY_SKIP_DUAL_CORE_WARNING(Settings.FILE_DOLPHIN, Settings.SECTION_INI_NETPLAY, "SkipDualCoreWarning", false);
 
     override val isOverridden: Boolean
         get() = NativeConfig.isOverridden(file, section, key)

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

@@ -1012,6 +1012,9 @@ It can efficiently compress both junk data and encrypted Wii data.
     <string name="netplay_start">Start</string>
     <string name="netplay_start_warning_title">Warning</string>
     <string name="netplay_start_warning_not_all_players_have_game">Not all players have the game. Do you really want to start?</string>
+    <string name="netplay_dual_core_warning_title">Dual Core Enabled</string>
+    <string name="netplay_dual_core_warning_message">Dual core during netplay is not recommended. It can cause performance issues and prevent certain games from booting.</string>
+    <string name="netplay_dont_warn_again">Don\'t warn again</string>
     <string name="netplay_chat_label">Chat</string>
     <string name="netplay_chat_send">Send</string>
     <string name="netplay_message_game_changed">Game changed to %1$s</string>