Backport LAN (#2131)

backport the old LAN feature to the modern melonDS codebase.

.github/workflows/build-ubuntu.yml

@@ -20,7 +20,7 @@ jobs:
       run: |
         sudo rm -f /etc/apt/sources.list.d/dotnetdev.list /etc/apt/sources.list.d/microsoft-prod.list
         sudo apt update
-        sudo apt install --allow-downgrades cmake ninja-build extra-cmake-modules libpcap0.8-dev libsdl2-dev \
+        sudo apt install --allow-downgrades cmake ninja-build extra-cmake-modules libpcap0.8-dev libsdl2-dev libenet-dev \
           qt6-{base,base-private,multimedia}-dev libarchive-dev libzstd-dev libfuse2
     - name: Configure
       run: cmake -B build -G Ninja -DUSE_QT6=ON -DCMAKE_INSTALL_PREFIX=/usr
@@ -63,7 +63,7 @@ jobs:
           apt update
           apt -y full-upgrade
           apt -y install git {gcc-12,g++-12}-aarch64-linux-gnu cmake ninja-build extra-cmake-modules \
-            {libsdl2,qt6-{base,base-private,multimedia},libarchive,libzstd}-dev:arm64 \
+            {libsdl2,qt6-{base,base-private,multimedia},libarchive,libzstd,libenet}-dev:arm64 \
             pkg-config dpkg-dev
       - name: Check out source
         uses: actions/checkout@v4

cmake/FindENet.cmake

@@ -0,0 +1,48 @@
+# - Try to find enet
+# Once done this will define
+#
+#  ENET_FOUND - system has enet
+#  ENET_INCLUDE_DIRS - the enet include directory
+#  ENET_LIBRARIES - the libraries needed to use enet
+#
+# $ENETDIR is an environment variable used for finding enet.
+#
+#  Borrowed from The Mana World
+#  http://themanaworld.org/
+#
+# Several changes and additions by Fabian 'x3n' Landau
+# Lots of simplifications by Adrian Friedli
+#                 > www.orxonox.net <
+
+FIND_PATH(ENET_INCLUDE_DIRS enet/enet.h
+    PATHS
+    $ENV{ENETDIR}
+    /usr/local
+    /usr
+    PATH_SUFFIXES include
+)
+
+FIND_LIBRARY(ENET_LIBRARY
+    NAMES enet
+    PATHS
+    $ENV{ENETDIR}
+    /usr/local
+    /usr
+    PATH_SUFFIXES lib
+)
+
+# handle the QUIETLY and REQUIRED arguments and set ENET_FOUND to TRUE if
+# all listed variables are TRUE
+INCLUDE(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(ENet DEFAULT_MSG ENET_LIBRARY ENET_INCLUDE_DIRS)
+
+IF (ENET_FOUND)
+    IF(WIN32)
+        SET(WINDOWS_ENET_DEPENDENCIES "ws2_32;winmm")
+        SET(ENET_LIBRARIES ${ENET_LIBRARY} ${WINDOWS_ENET_DEPENDENCIES})
+    ELSE(WIN32)
+        SET(ENET_LIBRARIES ${ENET_LIBRARY})
+    ENDIF(WIN32)
+ENDIF (ENET_FOUND)
+
+MARK_AS_ADVANCED(ENET_LIBRARY ENET_LIBRARIES ENET_INCLUDE_DIRS)

flake.lock

@@ -20,11 +20,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1722813957,
-        "narHash": "sha256-IAoYyYnED7P8zrBFMnmp7ydaJfwTnwcnqxUElC1I26Y=",
+        "lastModified": 1723175592,
+        "narHash": "sha256-M0xJ3FbDUc4fRZ84dPGx5VvgFsOzds77KiBMW/mMTnI=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "cb9a96f23c491c081b38eab96d22fa958043c9fa",
+        "rev": "5e0ca22929f3342b19569b21b2f3462f053e497b",
         "type": "github"
       },
       "original": {

flake.nix

@@ -37,6 +37,7 @@
           libarchive
           libGL
           libslirp
+          enet
         ]) ++ optionals isLinux [
           pkgs.wayland
           pkgs.kdePackages.qtwayland

src/Platform.h

@@ -270,6 +270,9 @@ bool Mutex_TryLock(Mutex* mutex);
 
 void Sleep(u64 usecs);
 
+u64 GetMSCount();
+u64 GetUSCount();
+
 
 // functions called when the NDS or GBA save files need to be written back to storage
 // savedata and savelen are always the entire save memory buffer and its full length

src/frontend/qt_sdl/CMakeLists.txt

@@ -51,6 +51,9 @@ set(SOURCES_QT_SDL
 
     CLI.h
     CLI.cpp
+
+    LANDialog.cpp
+    NetplayDialog.cpp
 )
 
 if (APPLE)

src/frontend/qt_sdl/EmuInstance.cpp

@@ -39,7 +39,7 @@
 #include "Config.h"
 #include "Platform.h"
 #include "Net.h"
-#include "LocalMP.h"
+#include "MPInterface.h"
 
 #include "NDS.h"
 #include "DSi.h"
@@ -62,11 +62,11 @@ using namespace melonDS::Platform;
 MainWindow* topWindow = nullptr;
 
 const string kWifiSettingsPath = "wfcsettings.bin";
-extern LocalMP localMp;
 extern Net net;
 
 
-EmuInstance::EmuInstance(int inst) : instanceID(inst),
+EmuInstance::EmuInstance(int inst) : deleting(false),
+    instanceID(inst),
     globalCfg(Config::GetGlobalTable()),
     localCfg(Config::GetLocalTable(inst))
 {
@@ -117,8 +117,10 @@ EmuInstance::EmuInstance(int inst) : instanceID(inst),
 
 EmuInstance::~EmuInstance()
 {
-    // TODO window cleanup and shit?
-    localMp.End(instanceID);
+    deleting = true;
+    deleteAllWindows();
+
+    MPInterface::Get().End(instanceID);
 
     emuThread->emuExit();
     emuThread->wait();
@@ -168,6 +170,44 @@ void EmuInstance::createWindow()
     emuThread->attachWindow(win);
 }
 
+void EmuInstance::deleteWindow(int id, bool close)
+{
+    if (id >= kMaxWindows) return;
+
+    MainWindow* win = windowList[id];
+    if (!win) return;
+
+    if (win->hasOpenGL() && win == mainWindow)
+    {
+        // we intentionally don't unpause here
+        emuThread->emuPause();
+        emuThread->deinitContext();
+    }
+
+    emuThread->detachWindow(win);
+
+    windowList[id] = nullptr;
+    numWindows--;
+
+    if (topWindow == win) topWindow = nullptr;
+    if (mainWindow == win) mainWindow = nullptr;
+
+    if (close)
+        win->close();
+
+    if ((!mainWindow) && (!deleting))
+    {
+        // if we closed this instance's main window, delete the instance
+        deleteEmuInstance(instanceID);
+    }
+}
+
+void EmuInstance::deleteAllWindows()
+{
+    for (int i = kMaxWindows-1; i >= 0; i--)
+        deleteWindow(i, true);
+}
+
 
 void EmuInstance::osdAddMessage(unsigned int color, const char* fmt, ...)
 {

src/frontend/qt_sdl/EmuInstance.h

@@ -91,6 +91,8 @@ public:
     std::string instanceFileSuffix();
 
     void createWindow();
+    void deleteWindow(int id, bool close);
+    void deleteAllWindows();
 
     void osdAddMessage(unsigned int color, const char* fmt, ...);
 
@@ -217,6 +219,8 @@ private:
     bool hotkeyPressed(int id)  { return hotkeyPress   & (1<<id); }
     bool hotkeyReleased(int id) { return hotkeyRelease & (1<<id); }
 
+    bool deleting;
+
     int instanceID;
 
     EmuThread* emuThread;

src/frontend/qt_sdl/EmuThread.cpp

@@ -151,6 +151,7 @@ void EmuThread::run()
 
     while (emuStatus != emuStatus_Exit)
     {
+        MPInterface::Get().Process();
         emuInstance->inputProcess();
 
         if (emuInstance->hotkeyPressed(HK_FastForwardToggle)) emit windowLimitFPSChange();

src/frontend/qt_sdl/LANDialog.cpp

@@ -0,0 +1,405 @@
+/*
+    Copyright 2016-2024 melonDS team
+
+    This file is part of melonDS.
+
+    melonDS is free software: you can redistribute it and/or modify it under
+    the terms of the GNU General Public License as published by the Free
+    Software Foundation, either version 3 of the License, or (at your option)
+    any later version.
+
+    melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
+    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with melonDS. If not, see http://www.gnu.org/licenses/.
+*/
+
+#include <stdio.h>
+#include <string.h>
+#include <queue>
+#include <vector>
+
+#include <QStandardItemModel>
+#include <QPushButton>
+#include <QInputDialog>
+#include <QMessageBox>
+
+#include "LANDialog.h"
+#include "Config.h"
+#include "main.h"
+#include "LAN.h"
+
+#include "ui_LANStartHostDialog.h"
+#include "ui_LANStartClientDialog.h"
+#include "ui_LANDialog.h"
+
+using namespace melonDS;
+
+
+LANStartClientDialog* lanClientDlg = nullptr;
+LANDialog* lanDlg = nullptr;
+
+#define lan() ((LAN&)MPInterface::Get())
+
+
+LANStartHostDialog::LANStartHostDialog(QWidget* parent) : QDialog(parent), ui(new Ui::LANStartHostDialog)
+{
+    ui->setupUi(this);
+    setAttribute(Qt::WA_DeleteOnClose);
+
+    setMPInterface(MPInterface_LAN);
+
+    // TODO: remember the last setting? so this doesn't suck massively
+    // we could also remember the player name (and auto-init it from the firmware name or whatever)
+    ui->sbNumPlayers->setRange(2, 16);
+    ui->sbNumPlayers->setValue(16);
+}
+
+LANStartHostDialog::~LANStartHostDialog()
+{
+    delete ui;
+}
+
+void LANStartHostDialog::done(int r)
+{
+    if (r == QDialog::Accepted)
+    {
+        if (ui->txtPlayerName->text().trimmed().isEmpty())
+        {
+            QMessageBox::warning(this, "melonDS", "Please enter a player name.");
+            return;
+        }
+
+        std::string player = ui->txtPlayerName->text().toStdString();
+        int numplayers = ui->sbNumPlayers->value();
+
+        if (!lan().StartHost(player.c_str(), numplayers))
+        {
+            QMessageBox::warning(this, "melonDS", "Failed to start LAN game.");
+            return;
+        }
+
+        lanDlg = LANDialog::openDlg(parentWidget());
+    }
+    else
+    {
+        setMPInterface(MPInterface_Local);
+    }
+
+    QDialog::done(r);
+}
+
+
+LANStartClientDialog::LANStartClientDialog(QWidget* parent) : QDialog(parent), ui(new Ui::LANStartClientDialog)
+{
+    ui->setupUi(this);
+    setAttribute(Qt::WA_DeleteOnClose);
+
+    setMPInterface(MPInterface_LAN);
+
+    QStandardItemModel* model = new QStandardItemModel();
+    ui->tvAvailableGames->setModel(model);
+    const QStringList listheader = {"Name", "Players", "Status", "Host IP"};
+    model->setHorizontalHeaderLabels(listheader);
+
+    connect(ui->tvAvailableGames->selectionModel(), SIGNAL(selectionChanged(const QItemSelection&, const QItemSelection&)),
+            this, SLOT(onGameSelectionChanged(const QItemSelection&, const QItemSelection&)));
+
+    ui->buttonBox->button(QDialogButtonBox::Ok)->setText("Connect");
+    ui->buttonBox->button(QDialogButtonBox::Ok)->setEnabled(false);
+
+    QPushButton* btn = ui->buttonBox->addButton("Direct connect...", QDialogButtonBox::ActionRole);
+    connect(btn, SIGNAL(clicked()), this, SLOT(onDirectConnect()));
+
+    lanClientDlg = this;
+    lan().StartDiscovery();
+
+    timerID = startTimer(1000);
+}
+
+LANStartClientDialog::~LANStartClientDialog()
+{
+    killTimer(timerID);
+
+    lanClientDlg = nullptr;
+    delete ui;
+}
+
+void LANStartClientDialog::onGameSelectionChanged(const QItemSelection& cur, const QItemSelection& prev)
+{
+    QModelIndexList indlist = cur.indexes();
+    if (indlist.count() == 0)
+    {
+        ui->buttonBox->button(QDialogButtonBox::Ok)->setEnabled(false);
+    }
+    else
+    {
+        ui->buttonBox->button(QDialogButtonBox::Ok)->setEnabled(true);
+    }
+}
+
+void LANStartClientDialog::on_tvAvailableGames_doubleClicked(QModelIndex index)
+{
+    done(QDialog::Accepted);
+}
+
+void LANStartClientDialog::onDirectConnect()
+{
+    if (ui->txtPlayerName->text().trimmed().isEmpty())
+    {
+        QMessageBox::warning(this, "melonDS", "Please enter a player name before connecting.");
+        return;
+    }
+
+    QString host = QInputDialog::getText(this, "Direct connect", "Host address:");
+    if (host.isEmpty()) return;
+
+    std::string hostname = host.toStdString();
+    std::string player = ui->txtPlayerName->text().toStdString();
+
+    setEnabled(false);
+    lan().EndDiscovery();
+    if (!lan().StartClient(player.c_str(), hostname.c_str()))
+    {
+        QString msg = QString("Failed to connect to the host %0.").arg(QString::fromStdString(hostname));
+        QMessageBox::warning(this, "melonDS", msg);
+        setEnabled(true);
+        lan().StartDiscovery();
+        return;
+    }
+
+    setEnabled(true);
+    lanDlg = LANDialog::openDlg(parentWidget());
+    QDialog::done(QDialog::Accepted);
+}
+
+void LANStartClientDialog::done(int r)
+{
+    if (r == QDialog::Accepted)
+    {
+        if (ui->txtPlayerName->text().trimmed().isEmpty())
+        {
+            QMessageBox::warning(this, "melonDS", "Please enter a player name before connecting.");
+            return;
+        }
+
+        QModelIndexList indlist = ui->tvAvailableGames->selectionModel()->selectedRows();
+        if (indlist.count() == 0) return;
+
+        QStandardItemModel* model = (QStandardItemModel*)ui->tvAvailableGames->model();
+        QStandardItem* item = model->item(indlist[0].row());
+        u32 addr = item->data().toUInt();
+        char hostname[16];
+        snprintf(hostname, 16, "%d.%d.%d.%d", (addr>>24), ((addr>>16)&0xFF), ((addr>>8)&0xFF), (addr&0xFF));
+
+        std::string player = ui->txtPlayerName->text().toStdString();
+
+        setEnabled(false);
+        lan().EndDiscovery();
+        if (!lan().StartClient(player.c_str(), hostname))
+        {
+            QString msg = QString("Failed to connect to the host %0.").arg(QString(hostname));
+            QMessageBox::warning(this, "melonDS", msg);
+            setEnabled(true);
+            lan().StartDiscovery();
+            return;
+        }
+
+        setEnabled(true);
+        lanDlg = LANDialog::openDlg(parentWidget());
+    }
+    else
+    {
+        lan().EndDiscovery();
+        setMPInterface(MPInterface_Local);
+    }
+
+    QDialog::done(r);
+}
+
+void LANStartClientDialog::timerEvent(QTimerEvent *event)
+{
+    doUpdateDiscoveryList();
+}
+
+void LANStartClientDialog::doUpdateDiscoveryList()
+{
+    auto disclist = lan().GetDiscoveryList();
+
+    QStandardItemModel* model = (QStandardItemModel*)ui->tvAvailableGames->model();
+    int curcount = model->rowCount();
+    int newcount = disclist.size();
+    if (curcount > newcount)
+    {
+        model->removeRows(newcount, curcount-newcount);
+    }
+    else if (curcount < newcount)
+    {
+        for (int i = curcount; i < newcount; i++)
+        {
+            QList<QStandardItem*> row;
+            row.append(new QStandardItem());
+            row.append(new QStandardItem());
+            row.append(new QStandardItem());
+            row.append(new QStandardItem());
+            model->appendRow(row);
+        }
+    }
+
+    int i = 0;
+    for (const auto& [key, data] : disclist)
+    {
+        model->item(i, 0)->setText(data.SessionName);
+        model->item(i, 0)->setData(QVariant(key));
+
+        QString plcount = QString("%0/%1").arg(data.NumPlayers).arg(data.MaxPlayers);
+        model->item(i, 1)->setText(plcount);
+
+        QString status;
+        switch (data.Status)
+        {
+            case 0: status = "Idle"; break;
+            case 1: status = "Playing"; break;
+        }
+        model->item(i, 2)->setText(status);
+
+        QString ip = QString("%0.%1.%2.%3").arg(key>>24).arg((key>>16)&0xFF).arg((key>>8)&0xFF).arg(key&0xFF);
+        model->item(i, 3)->setText(ip);
+
+        i++;
+    }
+}
+
+
+LANDialog::LANDialog(QWidget* parent) : QDialog(parent), ui(new Ui::LANDialog)
+{
+    ui->setupUi(this);
+    setAttribute(Qt::WA_DeleteOnClose);
+
+    QStandardItemModel* model = new QStandardItemModel();
+    ui->tvPlayerList->setModel(model);
+    const QStringList header = {"#", "Player", "Status", "Ping", "IP"};
+    model->setHorizontalHeaderLabels(header);
+
+    timerID = startTimer(1000);
+}
+
+LANDialog::~LANDialog()
+{
+    killTimer(timerID);
+
+    delete ui;
+}
+
+void LANDialog::on_btnLeaveGame_clicked()
+{
+    done(QDialog::Accepted);
+}
+
+void LANDialog::done(int r)
+{
+    bool showwarning = true;
+    if (lan().GetNumPlayers() < 2)
+        showwarning = false;
+
+    if (showwarning)
+    {
+        if (QMessageBox::warning(this, "melonDS", "Really leave this LAN game?",
+                                 QMessageBox::Yes | QMessageBox::No, QMessageBox::No) == QMessageBox::No)
+            return;
+    }
+
+    lan().EndSession();
+    setMPInterface(MPInterface_Local);
+
+    QDialog::done(r);
+}
+
+void LANDialog::timerEvent(QTimerEvent *event)
+{
+    doUpdatePlayerList();
+}
+
+void LANDialog::doUpdatePlayerList()
+{
+    auto playerlist = lan().GetPlayerList();
+    auto maxplayers = lan().GetMaxPlayers();
+
+    QStandardItemModel* model = (QStandardItemModel*)ui->tvPlayerList->model();
+    int curcount = model->rowCount();
+    int newcount = playerlist.size();
+    if (curcount > newcount)
+    {
+        model->removeRows(newcount, curcount-newcount);
+    }
+    else if (curcount < newcount)
+    {
+        for (int i = curcount; i < newcount; i++)
+        {
+            QList<QStandardItem*> row;
+            row.append(new QStandardItem());
+            row.append(new QStandardItem());
+            row.append(new QStandardItem());
+            row.append(new QStandardItem());
+            row.append(new QStandardItem());
+            model->appendRow(row);
+        }
+    }
+
+    int i = 0;
+    for (const auto& player : playerlist)
+    {
+        QString id = QString("%0/%1").arg(player.ID+1).arg(maxplayers);
+        model->item(i, 0)->setText(id);
+
+        QString name = player.Name;
+        model->item(i, 1)->setText(name);
+
+        QString status = "???";
+        switch (player.Status)
+        {
+            case LAN::Player_Client:
+                status = "Connected";
+                break;
+            case LAN::Player_Host:
+                status = "Game host";
+                break;
+            case LAN::Player_Connecting:
+                status = "Connecting";
+                break;
+            case LAN::Player_Disconnected:
+                status = "Connection lost";
+                break;
+        }
+        model->item(i, 2)->setText(status);
+
+        if (player.IsLocalPlayer)
+        {
+            model->item(i, 3)->setText("-");
+            model->item(i, 4)->setText("(local)");
+        }
+        else
+        {
+            if (player.Status == LAN::Player_Client ||
+                player.Status == LAN::Player_Host)
+            {
+                QString ping = QString("%0 ms").arg(player.Ping);
+                model->item(i, 3)->setText(ping);
+            }
+            else
+            {
+                model->item(i, 3)->setText("-");
+            }
+
+
+            u32 ip = player.Address;
+
+            QString ips = QString("%0.%1.%2.%3").arg(ip&0xFF).arg((ip>>8)&0xFF).arg((ip>>16)&0xFF).arg(ip>>24);
+            model->item(i, 4)->setText(ips);
+        }
+
+        i++;
+    }
+}

src/frontend/qt_sdl/LANDialog.h

@@ -0,0 +1,117 @@
+/*
+    Copyright 2016-2024 melonDS team
+
+    This file is part of melonDS.
+
+    melonDS is free software: you can redistribute it and/or modify it under
+    the terms of the GNU General Public License as published by the Free
+    Software Foundation, either version 3 of the License, or (at your option)
+    any later version.
+
+    melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
+    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with melonDS. If not, see http://www.gnu.org/licenses/.
+*/
+
+#ifndef LANDIALOG_H
+#define LANDIALOG_H
+
+#include <QDialog>
+#include <QMutex>
+#include <QItemSelection>
+
+#include "types.h"
+
+namespace Ui
+{
+    class LANStartHostDialog;
+    class LANStartClientDialog;
+    class LANDialog;
+}
+
+class LANStartHostDialog : public QDialog
+{
+Q_OBJECT
+
+public:
+    explicit LANStartHostDialog(QWidget* parent);
+    ~LANStartHostDialog();
+
+    static LANStartHostDialog* openDlg(QWidget* parent)
+    {
+        LANStartHostDialog* dlg = new LANStartHostDialog(parent);
+        dlg->open();
+        return dlg;
+    }
+
+private slots:
+    void done(int r);
+
+private:
+    Ui::LANStartHostDialog* ui;
+};
+
+class LANStartClientDialog : public QDialog
+{
+Q_OBJECT
+
+public:
+    explicit LANStartClientDialog(QWidget* parent);
+    ~LANStartClientDialog();
+
+    static LANStartClientDialog* openDlg(QWidget* parent)
+    {
+        LANStartClientDialog* dlg = new LANStartClientDialog(parent);
+        dlg->open();
+        return dlg;
+    }
+
+protected:
+    void timerEvent(QTimerEvent* event) override;
+
+private slots:
+    void onGameSelectionChanged(const QItemSelection& cur, const QItemSelection& prev);
+    void on_tvAvailableGames_doubleClicked(QModelIndex index);
+    void onDirectConnect();
+    void done(int r);
+
+    void doUpdateDiscoveryList();
+
+private:
+    Ui::LANStartClientDialog* ui;
+    int timerID;
+};
+
+class LANDialog : public QDialog
+{
+Q_OBJECT
+
+public:
+    explicit LANDialog(QWidget* parent);
+    ~LANDialog();
+
+    static LANDialog* openDlg(QWidget* parent)
+    {
+        LANDialog* dlg = new LANDialog(parent);
+        dlg->show();
+        return dlg;
+    }
+
+protected:
+    void timerEvent(QTimerEvent* event) override;
+
+private slots:
+    void on_btnLeaveGame_clicked();
+    void done(int r);
+
+    void doUpdatePlayerList();
+
+private:
+    Ui::LANDialog* ui;
+    int timerID;
+};
+
+#endif // LANDIALOG_H

src/frontend/qt_sdl/LANDialog.ui

@@ -0,0 +1,51 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>LANDialog</class>
+ <widget class="QDialog" name="LANDialog">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>522</width>
+    <height>391</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>LAN game - melonDS</string>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayout">
+   <item>
+    <layout class="QHBoxLayout" name="horizontalLayout">
+     <property name="leftMargin">
+      <number>0</number>
+     </property>
+     <item>
+      <widget class="QPushButton" name="btnLeaveGame">
+       <property name="text">
+        <string>Leave game</string>
+       </property>
+      </widget>
+     </item>
+     <item>
+      <spacer name="horizontalSpacer">
+       <property name="orientation">
+        <enum>Qt::Orientation::Horizontal</enum>
+       </property>
+       <property name="sizeHint" stdset="0">
+        <size>
+         <width>40</width>
+         <height>20</height>
+        </size>
+       </property>
+      </spacer>
+     </item>
+    </layout>
+   </item>
+   <item>
+    <widget class="QTreeView" name="tvPlayerList"/>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>

src/frontend/qt_sdl/LANStartClientDialog.ui

@@ -0,0 +1,117 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>LANStartClientDialog</class>
+ <widget class="QDialog" name="LANStartClientDialog">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>547</width>
+    <height>409</height>
+   </rect>
+  </property>
+  <property name="sizePolicy">
+   <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
+    <horstretch>0</horstretch>
+    <verstretch>0</verstretch>
+   </sizepolicy>
+  </property>
+  <property name="windowTitle">
+   <string>Join LAN game - melonDS</string>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayout">
+   <item>
+    <layout class="QHBoxLayout" name="horizontalLayout_2">
+     <item>
+      <widget class="QLabel" name="label">
+       <property name="text">
+        <string>Player name:</string>
+       </property>
+      </widget>
+     </item>
+     <item>
+      <widget class="QLineEdit" name="txtPlayerName">
+       <property name="sizePolicy">
+        <sizepolicy hsizetype="Fixed" vsizetype="Fixed">
+         <horstretch>0</horstretch>
+         <verstretch>0</verstretch>
+        </sizepolicy>
+       </property>
+       <property name="minimumSize">
+        <size>
+         <width>150</width>
+         <height>0</height>
+        </size>
+       </property>
+      </widget>
+     </item>
+     <item>
+      <spacer name="horizontalSpacer">
+       <property name="orientation">
+        <enum>Qt::Horizontal</enum>
+       </property>
+       <property name="sizeHint" stdset="0">
+        <size>
+         <width>40</width>
+         <height>20</height>
+        </size>
+       </property>
+      </spacer>
+     </item>
+    </layout>
+   </item>
+   <item>
+    <widget class="QTreeView" name="tvAvailableGames">
+     <property name="editTriggers">
+      <set>QAbstractItemView::NoEditTriggers</set>
+     </property>
+    </widget>
+   </item>
+   <item>
+    <widget class="QDialogButtonBox" name="buttonBox">
+     <property name="orientation">
+      <enum>Qt::Horizontal</enum>
+     </property>
+     <property name="standardButtons">
+      <set>QDialogButtonBox::Cancel|QDialogButtonBox::Ok</set>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>accepted()</signal>
+   <receiver>LANStartClientDialog</receiver>
+   <slot>accept()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>248</x>
+     <y>254</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>157</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>rejected()</signal>
+   <receiver>LANStartClientDialog</receiver>
+   <slot>reject()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>316</x>
+     <y>260</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>286</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+ </connections>
+</ui>

src/frontend/qt_sdl/LANStartHostDialog.ui

@@ -0,0 +1,97 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>LANStartHostDialog</class>
+ <widget class="QDialog" name="LANStartHostDialog">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>389</width>
+    <height>228</height>
+   </rect>
+  </property>
+  <property name="sizePolicy">
+   <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
+    <horstretch>0</horstretch>
+    <verstretch>0</verstretch>
+   </sizepolicy>
+  </property>
+  <property name="windowTitle">
+   <string>Host LAN game - melonDS</string>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayout">
+   <property name="sizeConstraint">
+    <enum>QLayout::SetFixedSize</enum>
+   </property>
+   <item>
+    <layout class="QFormLayout" name="formLayout">
+     <item row="0" column="0">
+      <widget class="QLabel" name="label">
+       <property name="text">
+        <string>Player name:</string>
+       </property>
+      </widget>
+     </item>
+     <item row="0" column="1">
+      <widget class="QLineEdit" name="txtPlayerName"/>
+     </item>
+     <item row="1" column="0">
+      <widget class="QLabel" name="label_2">
+       <property name="text">
+        <string>Number of players:</string>
+       </property>
+      </widget>
+     </item>
+     <item row="1" column="1">
+      <widget class="QSpinBox" name="sbNumPlayers"/>
+     </item>
+    </layout>
+   </item>
+   <item>
+    <widget class="QDialogButtonBox" name="buttonBox">
+     <property name="orientation">
+      <enum>Qt::Horizontal</enum>
+     </property>
+     <property name="standardButtons">
+      <set>QDialogButtonBox::Cancel|QDialogButtonBox::Ok</set>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>accepted()</signal>
+   <receiver>LANStartHostDialog</receiver>
+   <slot>accept()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>248</x>
+     <y>254</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>157</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>rejected()</signal>
+   <receiver>LANStartHostDialog</receiver>
+   <slot>reject()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>316</x>
+     <y>260</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>286</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+ </connections>
+</ui>

src/frontend/qt_sdl/NetplayDialog.cpp

@@ -0,0 +1,181 @@
+/*
+    Copyright 2016-2024 melonDS team
+
+    This file is part of melonDS.
+
+    melonDS is free software: you can redistribute it and/or modify it under
+    the terms of the GNU General Public License as published by the Free
+    Software Foundation, either version 3 of the License, or (at your option)
+    any later version.
+
+    melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
+    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with melonDS. If not, see http://www.gnu.org/licenses/.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <queue>
+
+#include <enet/enet.h>
+
+#include <QStandardItemModel>
+#include <QProcess>
+
+#include "NDS.h"
+#include "NDSCart.h"
+#include "main.h"
+//#include "IPC.h"
+#include "NetplayDialog.h"
+//#include "Input.h"
+//#include "ROMManager.h"
+#include "Config.h"
+#include "Savestate.h"
+#include "Platform.h"
+
+#include "ui_NetplayStartHostDialog.h"
+#include "ui_NetplayStartClientDialog.h"
+#include "ui_NetplayDialog.h"
+
+using namespace melonDS;
+
+
+extern EmuThread* emuThread;
+NetplayDialog* netplayDlg;
+
+
+NetplayStartHostDialog::NetplayStartHostDialog(QWidget* parent) : QDialog(parent), ui(new Ui::NetplayStartHostDialog)
+{
+    ui->setupUi(this);
+    setAttribute(Qt::WA_DeleteOnClose);
+
+    ui->txtPort->setText("8064");
+}
+
+NetplayStartHostDialog::~NetplayStartHostDialog()
+{
+    delete ui;
+}
+
+void NetplayStartHostDialog::done(int r)
+{
+    if (r == QDialog::Accepted)
+    {
+        std::string player = ui->txtPlayerName->text().toStdString();
+        int port = ui->txtPort->text().toInt();
+
+        // TODO validate input!!
+
+        netplayDlg = NetplayDialog::openDlg(parentWidget());
+
+        Netplay::StartHost(player.c_str(), port);
+    }
+
+    QDialog::done(r);
+}
+
+
+NetplayStartClientDialog::NetplayStartClientDialog(QWidget* parent) : QDialog(parent), ui(new Ui::NetplayStartClientDialog)
+{
+    ui->setupUi(this);
+    setAttribute(Qt::WA_DeleteOnClose);
+
+    ui->txtPort->setText("8064");
+}
+
+NetplayStartClientDialog::~NetplayStartClientDialog()
+{
+    delete ui;
+}
+
+void NetplayStartClientDialog::done(int r)
+{
+    if (r == QDialog::Accepted)
+    {
+        std::string player = ui->txtPlayerName->text().toStdString();
+        std::string host = ui->txtIPAddress->text().toStdString();
+        int port = ui->txtPort->text().toInt();
+
+        // TODO validate input!!
+
+        netplayDlg = NetplayDialog::openDlg(parentWidget());
+
+        Netplay::StartClient(player.c_str(), host.c_str(), port);
+    }
+
+    QDialog::done(r);
+}
+
+
+NetplayDialog::NetplayDialog(QWidget* parent) : QDialog(parent), ui(new Ui::NetplayDialog)
+{
+    ui->setupUi(this);
+    setAttribute(Qt::WA_DeleteOnClose);
+
+    QStandardItemModel* model = new QStandardItemModel();
+    ui->tvPlayerList->setModel(model);
+
+    connect(this, &NetplayDialog::sgUpdatePlayerList, this, &NetplayDialog::doUpdatePlayerList);
+}
+
+NetplayDialog::~NetplayDialog()
+{
+    delete ui;
+}
+
+void NetplayDialog::done(int r)
+{
+    // ???
+
+    QDialog::done(r);
+}
+
+void NetplayDialog::updatePlayerList(Netplay::Player* players, int num)
+{
+    emit sgUpdatePlayerList(players, num);
+}
+
+void NetplayDialog::doUpdatePlayerList(Netplay::Player* players, int num)
+{
+    QStandardItemModel* model = (QStandardItemModel*)ui->tvPlayerList->model();
+
+    model->clear();
+    model->setRowCount(num);
+
+    // TODO: remove IP column in final product
+
+    const QStringList header = {"#", "Player", "Status", "Ping", "IP"};
+    model->setHorizontalHeaderLabels(header);
+
+    for (int i = 0; i < num; i++)
+    {
+        Netplay::Player* player = &players[i];
+
+        QString id = QString("%0").arg(player->ID+1);
+        model->setItem(i, 0, new QStandardItem(id));
+
+        QString name = player->Name;
+        model->setItem(i, 1, new QStandardItem(name));
+
+        QString status;
+        switch (player->Status)
+        {
+            case 1: status = ""; break;
+            case 2: status = "Host"; break;
+            default: status = "ded"; break;
+        }
+        model->setItem(i, 2, new QStandardItem(status));
+
+        // TODO: ping
+        model->setItem(i, 3, new QStandardItem("x"));
+
+        char ip[32];
+        u32 addr = player->Address;
+        sprintf(ip, "%d.%d.%d.%d", addr&0xFF, (addr>>8)&0xFF, (addr>>16)&0xFF, addr>>24);
+        model->setItem(i, 4, new QStandardItem(ip));
+    }
+}

src/frontend/qt_sdl/NetplayDialog.h

@@ -0,0 +1,111 @@
+/*
+    Copyright 2016-2024 melonDS team
+
+    This file is part of melonDS.
+
+    melonDS is free software: you can redistribute it and/or modify it under
+    the terms of the GNU General Public License as published by the Free
+    Software Foundation, either version 3 of the License, or (at your option)
+    any later version.
+
+    melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
+    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with melonDS. If not, see http://www.gnu.org/licenses/.
+*/
+
+#ifndef NETPLAYDIALOG_H
+#define NETPLAYDIALOG_H
+
+#include <QDialog>
+
+#include "types.h"
+#include "Netplay.h"
+
+namespace Ui
+{
+    class NetplayStartHostDialog;
+    class NetplayStartClientDialog;
+    class NetplayDialog;
+}
+
+class NetplayStartHostDialog;
+class NetplayStartClientDialog;
+class NetplayDialog;
+
+class NetplayStartHostDialog : public QDialog
+{
+Q_OBJECT
+
+public:
+    explicit NetplayStartHostDialog(QWidget* parent);
+    ~NetplayStartHostDialog();
+
+    static NetplayStartHostDialog* openDlg(QWidget* parent)
+    {
+        NetplayStartHostDialog* dlg = new NetplayStartHostDialog(parent);
+        dlg->open();
+        return dlg;
+    }
+
+private slots:
+    void done(int r);
+
+private:
+    Ui::NetplayStartHostDialog* ui;
+};
+
+class NetplayStartClientDialog : public QDialog
+{
+Q_OBJECT
+
+public:
+    explicit NetplayStartClientDialog(QWidget* parent);
+    ~NetplayStartClientDialog();
+
+    static NetplayStartClientDialog* openDlg(QWidget* parent)
+    {
+        NetplayStartClientDialog* dlg = new NetplayStartClientDialog(parent);
+        dlg->open();
+        return dlg;
+    }
+
+private slots:
+    void done(int r);
+
+private:
+    Ui::NetplayStartClientDialog* ui;
+};
+
+class NetplayDialog : public QDialog
+{
+Q_OBJECT
+
+public:
+    explicit NetplayDialog(QWidget* parent);
+    ~NetplayDialog();
+
+    static NetplayDialog* openDlg(QWidget* parent)
+    {
+        NetplayDialog* dlg = new NetplayDialog(parent);
+        dlg->show();
+        return dlg;
+    }
+
+    void updatePlayerList(Netplay::Player* players, int num);
+
+signals:
+    void sgUpdatePlayerList(Netplay::Player* players, int num);
+
+private slots:
+    void done(int r);
+
+    void doUpdatePlayerList(Netplay::Player* players, int num);
+
+private:
+    Ui::NetplayDialog* ui;
+};
+
+#endif // NETPLAYDIALOG_H

src/frontend/qt_sdl/NetplayDialog.ui

@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>NetplayDialog</class>
+ <widget class="QDialog" name="NetplayDialog">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>522</width>
+    <height>391</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>NETPLAY SHITO</string>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayout_2">
+   <item>
+    <widget class="QLabel" name="lblStatus">
+     <property name="text">
+      <string>STATUS PLACEHOLDER</string>
+     </property>
+    </widget>
+   </item>
+   <item>
+    <widget class="QTreeView" name="tvPlayerList"/>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>

src/frontend/qt_sdl/NetplayStartClientDialog.ui

@@ -0,0 +1,107 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>NetplayStartClientDialog</class>
+ <widget class="QDialog" name="NetplayStartClientDialog">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>400</width>
+    <height>229</height>
+   </rect>
+  </property>
+  <property name="sizePolicy">
+   <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
+    <horstretch>0</horstretch>
+    <verstretch>0</verstretch>
+   </sizepolicy>
+  </property>
+  <property name="windowTitle">
+   <string>NETPLAY CLIENT</string>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayout">
+   <property name="sizeConstraint">
+    <enum>QLayout::SetFixedSize</enum>
+   </property>
+   <item>
+    <layout class="QFormLayout" name="formLayout">
+     <item row="0" column="0">
+      <widget class="QLabel" name="label">
+       <property name="text">
+        <string>Player name:</string>
+       </property>
+      </widget>
+     </item>
+     <item row="2" column="0">
+      <widget class="QLabel" name="label_2">
+       <property name="text">
+        <string>Host port:</string>
+       </property>
+      </widget>
+     </item>
+     <item row="0" column="1">
+      <widget class="QLineEdit" name="txtPlayerName"/>
+     </item>
+     <item row="2" column="1">
+      <widget class="QLineEdit" name="txtPort"/>
+     </item>
+     <item row="1" column="0">
+      <widget class="QLabel" name="label_3">
+       <property name="text">
+        <string>Host address:</string>
+       </property>
+      </widget>
+     </item>
+     <item row="1" column="1">
+      <widget class="QLineEdit" name="txtIPAddress"/>
+     </item>
+    </layout>
+   </item>
+   <item>
+    <widget class="QDialogButtonBox" name="buttonBox">
+     <property name="orientation">
+      <enum>Qt::Horizontal</enum>
+     </property>
+     <property name="standardButtons">
+      <set>QDialogButtonBox::Cancel|QDialogButtonBox::Ok</set>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>accepted()</signal>
+   <receiver>NetplayStartClientDialog</receiver>
+   <slot>accept()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>248</x>
+     <y>254</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>157</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>rejected()</signal>
+   <receiver>NetplayStartClientDialog</receiver>
+   <slot>reject()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>316</x>
+     <y>260</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>286</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+ </connections>
+</ui>

src/frontend/qt_sdl/NetplayStartHostDialog.ui

@@ -0,0 +1,97 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>NetplayStartHostDialog</class>
+ <widget class="QDialog" name="NetplayStartHostDialog">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>400</width>
+    <height>229</height>
+   </rect>
+  </property>
+  <property name="sizePolicy">
+   <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
+    <horstretch>0</horstretch>
+    <verstretch>0</verstretch>
+   </sizepolicy>
+  </property>
+  <property name="windowTitle">
+   <string>NETPLAY HOST</string>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayout">
+   <property name="sizeConstraint">
+    <enum>QLayout::SetFixedSize</enum>
+   </property>
+   <item>
+    <layout class="QFormLayout" name="formLayout">
+     <item row="0" column="0">
+      <widget class="QLabel" name="label">
+       <property name="text">
+        <string>Player name:</string>
+       </property>
+      </widget>
+     </item>
+     <item row="1" column="0">
+      <widget class="QLabel" name="label_2">
+       <property name="text">
+        <string>Port:</string>
+       </property>
+      </widget>
+     </item>
+     <item row="0" column="1">
+      <widget class="QLineEdit" name="txtPlayerName"/>
+     </item>
+     <item row="1" column="1">
+      <widget class="QLineEdit" name="txtPort"/>
+     </item>
+    </layout>
+   </item>
+   <item>
+    <widget class="QDialogButtonBox" name="buttonBox">
+     <property name="orientation">
+      <enum>Qt::Horizontal</enum>
+     </property>
+     <property name="standardButtons">
+      <set>QDialogButtonBox::Cancel|QDialogButtonBox::Ok</set>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>accepted()</signal>
+   <receiver>NetplayStartHostDialog</receiver>
+   <slot>accept()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>248</x>
+     <y>254</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>157</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>rejected()</signal>
+   <receiver>NetplayStartHostDialog</receiver>
+   <slot>reject()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>316</x>
+     <y>260</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>286</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+ </connections>
+</ui>

src/frontend/qt_sdl/Platform.cpp

@@ -38,7 +38,7 @@
 #include "main.h"
 #include "CameraManager.h"
 #include "Net.h"
-#include "LocalMP.h"
+#include "MPInterface.h"
 #include "SPI_Firmware.h"
 
 #ifdef __WIN32__
@@ -47,7 +47,7 @@
 #endif // __WIN32__
 
 extern CameraManager* camManager[2];
-extern melonDS::LocalMP localMp;
+
 extern melonDS::Net net;
 
 namespace melonDS::Platform
@@ -395,6 +395,16 @@ void Sleep(u64 usecs)
     QThread::usleep(usecs);
 }
 
+u64 GetMSCount()
+{
+    return sysTimer.elapsed();
+}
+
+u64 GetUSCount()
+{
+    return sysTimer.nsecsElapsed() / 1000;
+}
+
 
 void WriteNDSSave(const u8* savedata, u32 savelen, u32 writeoffset, u32 writelen, void* userdata)
 {
@@ -458,55 +468,55 @@ void WriteDateTime(int year, int month, int day, int hour, int minute, int secon
 void MP_Begin(void* userdata)
 {
     int inst = ((EmuInstance*)userdata)->getInstanceID();
-    localMp.Begin(inst);
+    MPInterface::Get().Begin(inst);
 }
 
 void MP_End(void* userdata)
 {
     int inst = ((EmuInstance*)userdata)->getInstanceID();
-    localMp.End(inst);
+    MPInterface::Get().End(inst);
 }
 
 int MP_SendPacket(u8* data, int len, u64 timestamp, void* userdata)
 {
     int inst = ((EmuInstance*)userdata)->getInstanceID();
-    return localMp.SendPacket(inst, data, len, timestamp);
+    return MPInterface::Get().SendPacket(inst, data, len, timestamp);
 }
 
 int MP_RecvPacket(u8* data, u64* timestamp, void* userdata)
 {
     int inst = ((EmuInstance*)userdata)->getInstanceID();
-    return localMp.RecvPacket(inst, data, timestamp);
+    return MPInterface::Get().RecvPacket(inst, data, timestamp);
 }
 
 int MP_SendCmd(u8* data, int len, u64 timestamp, void* userdata)
 {
     int inst = ((EmuInstance*)userdata)->getInstanceID();
-    return localMp.SendCmd(inst, data, len, timestamp);
+    return MPInterface::Get().SendCmd(inst, data, len, timestamp);
 }
 
 int MP_SendReply(u8* data, int len, u64 timestamp, u16 aid, void* userdata)
 {
     int inst = ((EmuInstance*)userdata)->getInstanceID();
-    return localMp.SendReply(inst, data, len, timestamp, aid);
+    return MPInterface::Get().SendReply(inst, data, len, timestamp, aid);
 }
 
 int MP_SendAck(u8* data, int len, u64 timestamp, void* userdata)
 {
     int inst = ((EmuInstance*)userdata)->getInstanceID();
-    return localMp.SendAck(inst, data, len, timestamp);
+    return MPInterface::Get().SendAck(inst, data, len, timestamp);
 }
 
 int MP_RecvHostPacket(u8* data, u64* timestamp, void* userdata)
 {
     int inst = ((EmuInstance*)userdata)->getInstanceID();
-    return localMp.RecvHostPacket(inst, data, timestamp);
+    return MPInterface::Get().RecvHostPacket(inst, data, timestamp);
 }
 
 u16 MP_RecvReplies(u8* data, u64 timestamp, u16 aidmask, void* userdata)
 {
     int inst = ((EmuInstance*)userdata)->getInstanceID();
-    return localMp.RecvReplies(inst, data, timestamp, aidmask);
+    return MPInterface::Get().RecvReplies(inst, data, timestamp, aidmask);
 }
 
 

src/frontend/qt_sdl/Window.cpp

@@ -73,7 +73,8 @@
 #include "Config.h"
 #include "version.h"
 #include "Savestate.h"
-#include "LocalMP.h"
+#include "MPInterface.h"
+#include "LANDialog.h"
 
 //#include "main_shaders.h"
 
@@ -88,7 +89,6 @@ using namespace melonDS;
 
 extern CameraManager* camManager[2];
 extern bool camStarted[2];
-extern LocalMP localMp;
 
 
 QString NdsRomMimeType = "application/x-nintendo-ds-rom";
@@ -432,6 +432,25 @@ MainWindow::MainWindow(int id, EmuInstance* inst, QWidget* parent) :
 
             actMPNewInstance = submenu->addAction("Launch new instance");
             connect(actMPNewInstance, &QAction::triggered, this, &MainWindow::onMPNewInstance);
+
+            submenu->addSeparator();
+
+            actLANStartHost = submenu->addAction("Host LAN game");
+            connect(actLANStartHost, &QAction::triggered, this, &MainWindow::onLANStartHost);
+
+            actLANStartClient = submenu->addAction("Join LAN game");
+            connect(actLANStartClient, &QAction::triggered, this, &MainWindow::onLANStartClient);
+
+            /*submenu->addSeparator();
+
+            actNPStartHost = submenu->addAction("NETPLAY HOST");
+            connect(actNPStartHost, &QAction::triggered, this, &MainWindow::onNPStartHost);
+
+            actNPStartClient = submenu->addAction("NETPLAY CLIENT");
+            connect(actNPStartClient, &QAction::triggered, this, &MainWindow::onNPStartClient);
+
+            actNPTest = submenu->addAction("NETPLAY GO");
+            connect(actNPTest, &QAction::triggered, this, &MainWindow::onNPTest);*/
         }
     }
     {
@@ -737,6 +756,8 @@ MainWindow::MainWindow(int id, EmuInstance* inst, QWidget* parent) :
 
     QObject::connect(qApp, &QApplication::applicationStateChanged, this, &MainWindow::onAppStateChanged);
     onUpdateInterfaceSettings();
+
+    updateMPInterface(MPInterface::GetType());
 }
 
 MainWindow::~MainWindow()
@@ -756,24 +777,9 @@ void MainWindow::closeEvent(QCloseEvent* event)
     QByteArray geom = saveGeometry();
     QByteArray enc = geom.toBase64(QByteArray::Base64Encoding);
     windowCfg.SetString("Geometry", enc.toStdString());
-
     Config::Save();
 
-    if (hasOGL && (windowID == 0))
-    {
-        // we intentionally don't unpause here
-        emuThread->emuPause();
-        emuThread->deinitContext();
-    }
-
-    emuThread->detachWindow(this);
-
-    if (windowID == 0)
-    {
-        int inst = emuInstance->instanceID;
-        deleteEmuInstance(inst);
-    }
-
+    emuInstance->deleteWindow(windowID, false);
     QMainWindow::closeEvent(event);
 }
 
@@ -1685,6 +1691,67 @@ void MainWindow::onMPNewInstance()
     createEmuInstance();
 }
 
+void MainWindow::onLANStartHost()
+{
+    if (!lanWarning(true)) return;
+    LANStartHostDialog::openDlg(this);
+}
+
+void MainWindow::onLANStartClient()
+{
+    if (!lanWarning(false)) return;
+    LANStartClientDialog::openDlg(this);
+}
+
+void MainWindow::onNPStartHost()
+{
+    //Netplay::StartHost();
+    //NetplayStartHostDialog::openDlg(this);
+}
+
+void MainWindow::onNPStartClient()
+{
+    //Netplay::StartClient();
+    //NetplayStartClientDialog::openDlg(this);
+}
+
+void MainWindow::onNPTest()
+{
+    // HAX
+    //Netplay::StartGame();
+}
+
+void MainWindow::updateMPInterface(MPInterfaceType type)
+{
+    // MP interface was changed, reflect it in the UI
+
+    bool enable = (type == MPInterface_Local);
+    actMPNewInstance->setEnabled(enable);
+    actLANStartHost->setEnabled(enable);
+    actLANStartClient->setEnabled(enable);
+    /*actNPStartHost->setEnabled(enable);
+    actNPStartClient->setEnabled(enable);
+    actNPTest->setEnabled(enable);*/
+}
+
+bool MainWindow::lanWarning(bool host)
+{
+    if (numEmuInstances() < 2)
+        return true;
+
+    QString verb = host ? "host" : "join";
+    QString msg = "Multiple emulator instances are currently open.\n"
+            "If you "+verb+" a LAN game now, all secondary instances will be closed.\n\n"
+            "Do you wish to continue?";
+
+    auto res = QMessageBox::warning(this, "melonDS", msg, QMessageBox::Yes|QMessageBox::No, QMessageBox::No);
+    if (res == QMessageBox::No)
+        return false;
+
+    deleteAllEmuInstances(1);
+    return true;
+}
+
 void MainWindow::onOpenEmuSettings()
 {
     emuThread->emuPause();
@@ -1840,7 +1907,7 @@ void MainWindow::onMPSettingsFinished(int res)
 {
     emuInstance->mpAudioMode = globalCfg.GetInt("MP.AudioMode");
     emuInstance->audioMute();
-    localMp.SetRecvTimeout(globalCfg.GetInt("MP.RecvTimeout"));
+    MPInterface::Get().SetRecvTimeout(globalCfg.GetInt("MP.RecvTimeout"));
 
     emuThread->emuUnpause();
 }

src/frontend/qt_sdl/Window.h

@@ -35,6 +35,7 @@
 
 #include "Screen.h"
 #include "Config.h"
+#include "MPInterface.h"
 
 
 class EmuInstance;
@@ -125,6 +126,9 @@ public:
 
     void osdAddMessage(unsigned int color, const char* msg);
 
+    // called when the MP interface is changed
+    void updateMPInterface(melonDS::MPInterfaceType type);
+
 protected:
     void keyPressEvent(QKeyEvent* event) override;
     void keyReleaseEvent(QKeyEvent* event) override;
@@ -167,6 +171,11 @@ private slots:
     void onRAMInfo();
     void onOpenTitleManager();
     void onMPNewInstance();
+    void onLANStartHost();
+    void onLANStartClient();
+    void onNPStartHost();
+    void onNPStartClient();
+    void onNPTest();
 
     void onOpenEmuSettings();
     void onEmuSettingsDialogFinished(int res);
@@ -232,6 +241,8 @@ private:
 
     void createScreenPanel();
 
+    bool lanWarning(bool host);
+
     bool showOSD;
 
     bool hasOGL;
@@ -279,6 +290,11 @@ public:
     QAction* actRAMInfo;
     QAction* actTitleManager;
     QAction* actMPNewInstance;
+    QAction* actLANStartHost;
+    QAction* actLANStartClient;
+    QAction* actNPStartHost;
+    QAction* actNPStartClient;
+    QAction* actNPTest;
 
     QAction* actEmuSettings;
 #ifdef __APPLE__

src/frontend/qt_sdl/main.cpp

@@ -22,18 +22,14 @@
 #include <string.h>
 
 #include <optional>
-#include <vector>
 #include <string>
-#include <algorithm>
 
-#include <QProcess>
 #include <QApplication>
+#include <QStyle>
 #include <QMessageBox>
 #include <QMenuBar>
-#include <QMimeDatabase>
 #include <QFileDialog>
 #include <QInputDialog>
-#include <QPaintEvent>
 #include <QPainter>
 #include <QKeyEvent>
 #include <QMimeData>
@@ -57,24 +53,14 @@
 #include "duckstation/gl/context.h"
 
 #include "main.h"
-#include "CheatsDialog.h"
-#include "DateTimeDialog.h"
-#include "EmuSettingsDialog.h"
-#include "InputConfig/InputConfigDialog.h"
-#include "VideoSettingsDialog.h"
-#include "ROMInfoDialog.h"
-#include "RAMInfoDialog.h"
-#include "PowerManagement/PowerManagementDialog.h"
-
 #include "version.h"
 
 #include "Config.h"
-#include "DSi.h"
 
 #include "EmuInstance.h"
 #include "ArchiveUtil.h"
 #include "CameraManager.h"
-#include "LocalMP.h"
+#include "MPInterface.h"
 #include "Net.h"
 
 #include "CLI.h"
@@ -87,7 +73,6 @@ using namespace melonDS;
 QString* systemThemeName;
 
 
-
 QString emuDirectory;
 
 const int kMaxEmuInstances = 16;
@@ -95,10 +80,14 @@ EmuInstance* emuInstances[kMaxEmuInstances];
 
 CameraManager* camManager[2];
 bool camStarted[2];
-LocalMP localMp;
+
 std::optional<LibPCap> pcap;
 Net net;
 
+
+QElapsedTimer sysTimer;
+
+
 void NetInit()
 {
     Config::Table cfg = Config::GetGlobalTable();
@@ -159,12 +148,25 @@ void deleteEmuInstance(int id)
     emuInstances[id] = nullptr;
 }
 
-void deleteAllEmuInstances()
+void deleteAllEmuInstances(int first)
 {
-    for (int i = 0; i < kMaxEmuInstances; i++)
+    for (int i = first; i < kMaxEmuInstances; i++)
         deleteEmuInstance(i);
 }
 
+int numEmuInstances()
+{
+    int ret = 0;
+
+    for (int i = 0; i < kMaxEmuInstances; i++)
+    {
+        if (emuInstances[i])
+            ret++;
+    }
+
+    return ret;
+}
+
 
 void pathInit()
 {
@@ -203,6 +205,28 @@ void pathInit()
 }
 
 
+void setMPInterface(MPInterfaceType type)
+{
+    // switch to the requested MP interface
+    MPInterface::Set(type);
+
+    // set receive timeout
+    // TODO: different settings per interface?
+    MPInterface::Get().SetRecvTimeout(Config::GetGlobalTable().GetInt("MP.RecvTimeout"));
+
+    // update UI appropriately
+    // TODO: decide how to deal with multi-window when it becomes a thing
+    for (int i = 0; i < kMaxEmuInstances; i++)
+    {
+        EmuInstance* inst = emuInstances[i];
+        if (!inst) continue;
+
+        MainWindow* win = inst->getMainWindow();
+        if (win) win->updateMPInterface(type);
+    }
+}
+
+
 
 MelonApplication::MelonApplication(int& argc, char** argv)
     : QApplication(argc, argv)
@@ -237,6 +261,7 @@ bool MelonApplication::event(QEvent *event)
 
 int main(int argc, char** argv)
 {
+    sysTimer.start();
     srand(time(nullptr));
 
     for (int i = 0; i < kMaxEmuInstances; i++)
@@ -308,7 +333,10 @@ int main(int argc, char** argv)
         }
     }
 
-    // localMp is initialized at this point
+    // default MP interface type is local MP
+    // this will be changed if a LAN or netplay session is initiated
+    setMPInterface(MPInterface_Local);
+
     NetInit();
 
     createEmuInstance();

src/frontend/qt_sdl/main.h

@@ -22,19 +22,14 @@
 #include "glad/glad.h"
 
 #include <QApplication>
-#include <QWidget>
-#include <QWindow>
-#include <QMainWindow>
-#include <QImage>
-#include <QActionGroup>
-#include <QTimer>
-#include <QScreen>
-#include <QCloseEvent>
+#include <QEvent>
+#include <QElapsedTimer>
 
 #include "EmuInstance.h"
 #include "Window.h"
 #include "EmuThread.h"
 #include "ScreenLayout.h"
+#include "MPInterface.h"
 
 class MelonApplication : public QApplication
 {
@@ -48,8 +43,13 @@ public:
 extern QString* systemThemeName;
 extern QString emuDirectory;
 
+extern QElapsedTimer sysTimer;
+
 bool createEmuInstance();
 void deleteEmuInstance(int id);
-void deleteAllEmuInstances();
+void deleteAllEmuInstances(int first = 0);
+int numEmuInstances();
+
+void setMPInterface(melonDS::MPInterfaceType type);
 
 #endif // MAIN_H

src/net/CMakeLists.txt

@@ -6,6 +6,9 @@ add_library(net-utils STATIC
     Net_Slirp.cpp
     PacketDispatcher.cpp
     LocalMP.cpp
+    LAN.cpp
+    Netplay.cpp
+    MPInterface.cpp
 )
 
 target_include_directories(net-utils PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}")
@@ -21,3 +24,12 @@ else()
     add_subdirectory(libslirp EXCLUDE_FROM_ALL)
     target_link_libraries(net-utils PUBLIC slirp)
 endif()
+
+if (USE_VCPKG)
+    find_package(unofficial-enet CONFIG REQUIRED)
+    target_link_libraries(net-utils PRIVATE unofficial::enet::enet)
+else()
+    pkg_check_modules(ENet REQUIRED IMPORTED_TARGET libenet)
+    fix_interface_includes(PkgConfig::ENet)
+    target_link_libraries(net-utils PUBLIC PkgConfig::ENet)
+endif()

src/net/LAN.h

@@ -0,0 +1,156 @@
+/*
+    Copyright 2016-2024 melonDS team
+
+    This file is part of melonDS.
+
+    melonDS is free software: you can redistribute it and/or modify it under
+    the terms of the GNU General Public License as published by the Free
+    Software Foundation, either version 3 of the License, or (at your option)
+    any later version.
+
+    melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
+    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with melonDS. If not, see http://www.gnu.org/licenses/.
+*/
+
+#ifndef LAN_H
+#define LAN_H
+
+#include <string>
+#include <vector>
+#include <map>
+#include <queue>
+
+#include <enet/enet.h>
+
+#ifndef socket_t
+    #ifdef __WIN32__
+        #include <winsock2.h>
+        #define socket_t    SOCKET
+    #else
+        #define socket_t    int
+    #endif
+#endif
+
+#include "types.h"
+#include "Platform.h"
+#include "MPInterface.h"
+
+namespace melonDS
+{
+
+class LAN : public MPInterface
+{
+public:
+    LAN() noexcept;
+    LAN(const LAN&) = delete;
+    LAN& operator=(const LAN&) = delete;
+    LAN(LAN&& other) = delete;
+    LAN& operator=(LAN&& other) = delete;
+    ~LAN() noexcept;
+
+    enum PlayerStatus
+    {
+        Player_None = 0,        // no player in this entry
+        Player_Client,          // game client
+        Player_Host,            // game host
+        Player_Connecting,      // player still connecting
+        Player_Disconnected,    // player disconnected
+    };
+
+    struct Player
+    {
+        int ID;
+        char Name[32];
+        PlayerStatus Status;
+        u32 Address;
+
+        bool IsLocalPlayer;
+        u32 Ping;
+    };
+
+    struct DiscoveryData
+    {
+        u32 Magic;
+        u32 Version;
+        u32 Tick;
+        char SessionName[64];
+        u8 NumPlayers;
+        u8 MaxPlayers;
+        u8 Status; // 0=idle 1=playing
+    };
+
+    bool StartDiscovery();
+    void EndDiscovery();
+    bool StartHost(const char* player, int numplayers);
+    bool StartClient(const char* player, const char* host);
+    void EndSession();
+
+    std::map<u32, DiscoveryData> GetDiscoveryList();
+    std::vector<Player> GetPlayerList();
+    int GetNumPlayers() { return NumPlayers; }
+    int GetMaxPlayers() { return MaxPlayers; }
+
+    void Process() override;
+
+    void Begin(int inst) override;
+    void End(int inst) override;
+
+    int SendPacket(int inst, u8* data, int len, u64 timestamp) override;
+    int RecvPacket(int inst, u8* data, u64* timestamp) override;
+    int SendCmd(int inst, u8* data, int len, u64 timestamp) override;
+    int SendReply(int inst, u8* data, int len, u64 timestamp, u16 aid) override;
+    int SendAck(int inst, u8* data, int len, u64 timestamp) override;
+    int RecvHostPacket(int inst, u8* data, u64* timestamp) override;
+    u16 RecvReplies(int inst, u8* data, u64 timestamp, u16 aidmask) override;
+
+private:
+    bool Inited;
+    bool Active;
+    bool IsHost;
+
+    ENetHost* Host;
+    ENetPeer* RemotePeers[16];
+
+    socket_t DiscoverySocket;
+    u32 DiscoveryLastTick;
+    std::map<u32, DiscoveryData> DiscoveryList;
+    Platform::Mutex* DiscoveryMutex;
+
+    Player Players[16];
+    int NumPlayers;
+    int MaxPlayers;
+    Platform::Mutex* PlayersMutex;
+
+    Player MyPlayer;
+    u32 HostAddress;
+
+    u16 ConnectedBitmask;
+
+    int MPRecvTimeout;
+    int LastHostID;
+    ENetPeer* LastHostPeer;
+    std::queue<ENetPacket*> RXQueue;
+
+    u32 FrameCount;
+
+    void ProcessDiscovery();
+
+    void HostUpdatePlayerList();
+    void ClientUpdatePlayerList();
+
+    void ProcessHostEvent(ENetEvent& event);
+    void ProcessClientEvent(ENetEvent& event);
+    void ProcessEvent(ENetEvent& event);
+    void ProcessLAN(int type);
+
+    int SendPacketGeneric(u32 type, u8* packet, int len, u64 timestamp);
+    int RecvPacketGeneric(u8* packet, bool block, u64* timestamp);
+};
+
+}
+
+#endif // LAN_H

src/net/LocalMP.cpp

@@ -19,8 +19,6 @@
 #include <cstring>
 
 #include "LocalMP.h"
-#include "Platform.h"
-#include "types.h"
 
 using namespace melonDS;
 using namespace melonDS::Platform;

src/net/LocalMP.h

@@ -21,6 +21,7 @@
 
 #include "types.h"
 #include "Platform.h"
+#include "MPInterface.h"
 
 namespace melonDS
 {
@@ -33,20 +34,11 @@ struct MPStatusData
     u16 MPReplyBitmask;   // bitmask of which clients replied in time
 };
 
-struct MPPacketHeader
-{
-    u32 Magic;
-    u32 SenderID;
-    u32 Type;       // 0=regular 1=CMD 2=reply 3=ack
-    u32 Length;
-    u64 Timestamp;
-};
-
 constexpr u32 kPacketQueueSize = 0x10000;
 constexpr u32 kReplyQueueSize = 0x10000;
 constexpr u32 kMaxFrameSize = 0x948;
 
-class LocalMP
+class LocalMP : public MPInterface
 {
 public:
     LocalMP() noexcept;
@@ -56,8 +48,7 @@ public:
     LocalMP& operator=(LocalMP&& other) = delete;
     ~LocalMP() noexcept;
 
-    [[nodiscard]] int GetRecvTimeout() const noexcept { return RecvTimeout; }
-    void SetRecvTimeout(int timeout) noexcept { RecvTimeout = timeout; }
+    void Process() {}
 
     void Begin(int inst);
     void End(int inst);
@@ -69,11 +60,13 @@ public:
     int SendAck(int inst, u8* data, int len, u64 timestamp);
     int RecvHostPacket(int inst, u8* data, u64* timestamp);
     u16 RecvReplies(int inst, u8* data, u64 timestamp, u16 aidmask);
+
 private:
     void FIFORead(int inst, int fifo, void* buf, int len) noexcept;
     void FIFOWrite(int inst, int fifo, void* buf, int len) noexcept;
     int SendPacketGeneric(int inst, u32 type, u8* packet, int len, u64 timestamp) noexcept;
     int RecvPacketGeneric(int inst, u8* packet, bool block, u64* timestamp) noexcept;
+
     Platform::Mutex* MPQueueLock;
     MPStatusData MPStatus {};
     u8 MPPacketQueue[kPacketQueueSize] {};
@@ -81,8 +74,6 @@ private:
     u32 PacketReadOffset[16] {};
     u32 ReplyReadOffset[16] {};
 
-    int RecvTimeout = 25;
-
     int LastHostID = -1;
     Platform::Semaphore* SemPool[32] {};
 };

src/net/MPInterface.cpp

@@ -0,0 +1,68 @@
+/*
+    Copyright 2016-2024 melonDS team
+
+    This file is part of melonDS.
+
+    melonDS is free software: you can redistribute it and/or modify it under
+    the terms of the GNU General Public License as published by the Free
+    Software Foundation, either version 3 of the License, or (at your option)
+    any later version.
+
+    melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
+    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with melonDS. If not, see http://www.gnu.org/licenses/.
+*/
+
+#include "MPInterface.h"
+#include "LocalMP.h"
+#include "LAN.h"
+
+namespace melonDS
+{
+
+class DummyMP : public MPInterface
+{
+public:
+    void Process() override {}
+
+    void Begin(int inst) override {}
+    void End(int inst) override {}
+
+    int SendPacket(int inst, u8* data, int len, u64 timestamp) override { return 0; }
+    int RecvPacket(int inst, u8* data, u64* timestamp) override { return 0; }
+    int SendCmd(int inst, u8* data, int len, u64 timestamp) override { return 0; }
+    int SendReply(int inst, u8* data, int len, u64 timestamp, u16 aid) override { return 0; }
+    int SendAck(int inst, u8* data, int len, u64 timestamp) override { return 0; }
+    int RecvHostPacket(int inst, u8* data, u64* timestamp) override { return 0; }
+    u16 RecvReplies(int inst, u8* data, u64 timestamp, u16 aidmask) override { return 0; }
+};
+
+
+std::unique_ptr<MPInterface> MPInterface::Current(std::make_unique<DummyMP>());
+MPInterfaceType MPInterface::CurrentType = MPInterface_Dummy;
+
+
+void MPInterface::Set(MPInterfaceType type)
+{
+    switch (type)
+    {
+    case MPInterface_Local:
+        Current = std::make_unique<LocalMP>();
+        break;
+
+    case MPInterface_LAN:
+        Current = std::make_unique<LAN>();
+        break;
+
+    default:
+        Current = std::make_unique<DummyMP>();
+        break;
+    }
+
+    CurrentType = type;
+}
+
+}

src/net/MPInterface.h

@@ -0,0 +1,82 @@
+/*
+    Copyright 2016-2024 melonDS team
+
+    This file is part of melonDS.
+
+    melonDS is free software: you can redistribute it and/or modify it under
+    the terms of the GNU General Public License as published by the Free
+    Software Foundation, either version 3 of the License, or (at your option)
+    any later version.
+
+    melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
+    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with melonDS. If not, see http://www.gnu.org/licenses/.
+*/
+
+#ifndef MPINTERFACE_H
+#define MPINTERFACE_H
+
+#include <memory>
+#include "types.h"
+
+namespace melonDS
+{
+
+// TODO: provision for excluding unwanted interfaces at compile time
+enum MPInterfaceType
+{
+    MPInterface_Dummy = -1,
+    MPInterface_Local,
+    MPInterface_LAN,
+    MPInterface_Netplay,
+};
+
+struct MPPacketHeader
+{
+    u32 Magic;
+    u32 SenderID;
+    u32 Type;       // 0=regular 1=CMD 2=reply 3=ack
+    u32 Length;
+    u64 Timestamp;
+};
+
+class MPInterface
+{
+public:
+    virtual ~MPInterface() = default;
+
+    static MPInterface& Get() { return *Current; }
+    static MPInterfaceType GetType() { return CurrentType; }
+    static void Set(MPInterfaceType type);
+
+    [[nodiscard]] int GetRecvTimeout() const noexcept { return RecvTimeout; }
+    void SetRecvTimeout(int timeout) noexcept { RecvTimeout = timeout; }
+
+    // function called every video frame
+    virtual void Process() = 0;
+
+    virtual void Begin(int inst) = 0;
+    virtual void End(int inst) = 0;
+
+    virtual int SendPacket(int inst, u8* data, int len, u64 timestamp) = 0;
+    virtual int RecvPacket(int inst, u8* data, u64* timestamp) = 0;
+    virtual int SendCmd(int inst, u8* data, int len, u64 timestamp) = 0;
+    virtual int SendReply(int inst, u8* data, int len, u64 timestamp, u16 aid) = 0;
+    virtual int SendAck(int inst, u8* data, int len, u64 timestamp) = 0;
+    virtual int RecvHostPacket(int inst, u8* data, u64* timestamp) = 0;
+    virtual u16 RecvReplies(int inst, u8* data, u64 timestamp, u16 aidmask) = 0;
+
+protected:
+    int RecvTimeout = 25;
+
+private:
+    static MPInterfaceType CurrentType;
+    static std::unique_ptr<MPInterface> Current;
+};
+
+}
+
+#endif // MPINTERFACE_H

src/net/Netplay.h

@@ -0,0 +1,57 @@
+/*
+    Copyright 2016-2024 melonDS team
+
+    This file is part of melonDS.
+
+    melonDS is free software: you can redistribute it and/or modify it under
+    the terms of the GNU General Public License as published by the Free
+    Software Foundation, either version 3 of the License, or (at your option)
+    any later version.
+
+    melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
+    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with melonDS. If not, see http://www.gnu.org/licenses/.
+*/
+
+#ifndef NETPLAY_H
+#define NETPLAY_H
+
+#include "types.h"
+
+namespace Netplay
+{
+
+struct Player
+{
+    int ID;
+    char Name[32];
+    int Status; // 0=no player 1=normal 2=host 3=connecting
+    melonDS::u32 Address;
+};
+
+
+extern bool Active;
+
+bool Init();
+void DeInit();
+
+void StartHost(const char* player, int port);
+void StartClient(const char* player, const char* host, int port);
+void StartMirror(const Player* player);
+
+melonDS::u32 PlayerAddress(int id);
+
+void StartGame();
+void StartLocal();
+
+void StartGame();
+
+void ProcessFrame();
+void ProcessInput();
+
+}
+
+#endif // NETPLAY_H

vcpkg.json

@@ -3,7 +3,8 @@
 	"dependencies": [
 		"sdl2",
 		"libarchive",
-		"zstd"
+		"zstd",
+		"enet"
 	],
 	"features": {
 		"qt6": {