Add "Separate Windows" LayoutOption (#6177)

src/citra/citra.cpp

@@ -35,6 +35,7 @@
 #include "core/loader/loader.h"
 #include "core/movie.h"
 #include "core/settings.h"
+#include "input_common/main.h"
 #include "network/network.h"
 #include "video_core/renderer_base.h"
 
@@ -359,11 +360,23 @@ int main(int argc, char** argv) {
     // Register generic image interface
     Core::System::GetInstance().RegisterImageInterface(std::make_shared<LodePNGImageInterface>());
 
-    std::unique_ptr<EmuWindow_SDL2> emu_window{std::make_unique<EmuWindow_SDL2>(fullscreen)};
+    EmuWindow_SDL2::InitializeSDL2();
-    Frontend::ScopeAcquireContext scope(*emu_window);
-    Core::System& system = Core::System::GetInstance();
 
-    const Core::System::ResultStatus load_result{system.Load(*emu_window, filepath)};
+    const auto emu_window{std::make_unique<EmuWindow_SDL2>(fullscreen, false)};
+    const bool use_secondary_window{Settings::values.layout_option ==
+                                    Settings::LayoutOption::SeparateWindows};
+    const auto secondary_window =
+        use_secondary_window ? std::make_unique<EmuWindow_SDL2>(false, true) : nullptr;
+
+    Frontend::ScopeAcquireContext scope(*emu_window);
+
+    LOG_INFO(Frontend, "Citra Version: {} | {}-{}", Common::g_build_fullname, Common::g_scm_branch,
+             Common::g_scm_desc);
+    Settings::LogSettings();
+
+    Core::System& system = Core::System::GetInstance();
+    const Core::System::ResultStatus load_result{
+        system.Load(*emu_window, filepath, secondary_window.get())};
 
     switch (load_result) {
     case Core::System::ResultStatus::ErrorGetLoader:
@@ -431,7 +444,12 @@ int main(int argc, char** argv) {
         system.VideoDumper().StartDumping(dump_video, layout);
     }
 
-    std::thread render_thread([&emu_window] { emu_window->Present(); });
+    std::thread main_render_thread([&emu_window] { emu_window->Present(); });
+    std::thread secondary_render_thread([&secondary_window] {
+        if (secondary_window) {
+            secondary_window->Present();
+        }
+    });
 
     std::atomic_bool stop_run;
     system.Renderer().Rasterizer()->LoadDiskResources(
@@ -440,7 +458,11 @@ int main(int argc, char** argv) {
                       total);
         });
 
-    while (emu_window->IsOpen()) {
+    const auto secondary_is_open = [&secondary_window] {
+        // if the secondary window isn't created, it shouldn't affect the main loop
+        return secondary_window ? secondary_window->IsOpen() : true;
+    };
+    while (emu_window->IsOpen() && secondary_is_open()) {
         const auto result = system.RunLoop();
 
         switch (result) {
@@ -454,13 +476,21 @@ int main(int argc, char** argv) {
             break;
         }
     }
-    render_thread.join();
+    emu_window->RequestClose();
+    if (secondary_window) {
+        secondary_window->RequestClose();
+    }
+    main_render_thread.join();
+    secondary_render_thread.join();
 
     Core::Movie::GetInstance().Shutdown();
     if (system.VideoDumper().IsDumping()) {
         system.VideoDumper().StopDumping();
     }
 
+    Network::Shutdown();
+    InputCommon::Shutdown();
+
     system.Shutdown();
 
     detached_tasks.WaitForAllTasks();

src/citra/default_ini.h

@@ -182,7 +182,11 @@ filter_mode =
 
 [Layout]
 # Layout for the screen inside the render window.
-# 0 (default): Default Top Bottom Screen, 1: Single Screen Only, 2: Large Screen Small Screen, 3: Side by Side
+# 0 (default): Default Top Bottom Screen
+# 1: Single Screen Only
+# 2: Large Screen Small Screen
+# 3: Side by Side
+# 4: Separate Windows
 layout_option =
 
 # Toggle custom layout (using the settings below) on or off.

src/citra/emu_window/emu_window_sdl2.cpp

@@ -135,18 +135,8 @@ void EmuWindow_SDL2::Fullscreen() {
     SDL_MaximizeWindow(render_window);
 }
 
-EmuWindow_SDL2::EmuWindow_SDL2(bool fullscreen) {
+EmuWindow_SDL2::EmuWindow_SDL2(bool fullscreen, bool is_secondary) : EmuWindow(is_secondary) {
     // Initialize the window
-    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_GAMECONTROLLER) < 0) {
-        LOG_CRITICAL(Frontend, "Failed to initialize SDL2: {}! Exiting...", SDL_GetError());
-        exit(1);
-    }
-
-    InputCommon::Init();
-    Network::Init();
-
-    SDL_SetMainReady();
-
     if (Settings::values.use_gles) {
         SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
         SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
@@ -201,6 +191,7 @@ EmuWindow_SDL2::EmuWindow_SDL2(bool fullscreen) {
         exit(1);
     }
 
+    render_window_id = SDL_GetWindowID(render_window);
     auto gl_load_func = Settings::values.use_gles ? gladLoadGLES2Loader : gladLoadGLLoader;
 
     if (!gl_load_func(static_cast<GLADloadproc>(SDL_GL_GetProcAddress))) {
@@ -211,19 +202,26 @@ EmuWindow_SDL2::EmuWindow_SDL2(bool fullscreen) {
     OnResize();
     OnMinimalClientAreaChangeRequest(GetActiveConfig().min_client_area_size);
     SDL_PumpEvents();
-    LOG_INFO(Frontend, "Citra Version: {} | {}-{}", Common::g_build_fullname, Common::g_scm_branch,
-             Common::g_scm_desc);
-    Settings::LogSettings();
 }
 
 EmuWindow_SDL2::~EmuWindow_SDL2() {
     core_context.reset();
-    Network::Shutdown();
-    InputCommon::Shutdown();
     SDL_GL_DeleteContext(window_context);
     SDL_Quit();
 }
 
+void EmuWindow_SDL2::InitializeSDL2() {
+    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_GAMECONTROLLER) < 0) {
+        LOG_CRITICAL(Frontend, "Failed to initialize SDL2: {}! Exiting...", SDL_GetError());
+        exit(1);
+    }
+
+    InputCommon::Init();
+    Network::Init();
+
+    SDL_SetMainReady();
+}
+
 std::unique_ptr<Frontend::GraphicsContext> EmuWindow_SDL2::CreateSharedContext() const {
     return std::make_unique<SharedContext_SDL2>();
 }
@@ -240,7 +238,7 @@ void EmuWindow_SDL2::Present() {
     SDL_GL_MakeCurrent(render_window, window_context);
     SDL_GL_SetSwapInterval(1);
     while (IsOpen()) {
-        VideoCore::g_renderer->TryPresent(100);
+        VideoCore::g_renderer->TryPresent(100, is_secondary);
         SDL_GL_SwapWindow(render_window);
     }
     SDL_GL_MakeCurrent(render_window, nullptr);
@@ -248,9 +246,14 @@ void EmuWindow_SDL2::Present() {
 
 void EmuWindow_SDL2::PollEvents() {
     SDL_Event event;
+    std::vector<SDL_Event> other_window_events;
 
     // SDL_PollEvent returns 0 when there are no more events in the event queue
     while (SDL_PollEvent(&event)) {
+        if (event.window.windowID != render_window_id) {
+            other_window_events.push_back(event);
+            continue;
+        }
         switch (event.type) {
         case SDL_WINDOWEVENT:
             switch (event.window.event) {
@@ -299,16 +302,13 @@ void EmuWindow_SDL2::PollEvents() {
             break;
         }
     }
-
+    for (auto& e : other_window_events) {
-    const u32 current_time = SDL_GetTicks();
+        // This is a somewhat hacky workaround to re-emit window events meant for another window
-    if (current_time > last_time + 2000) {
+        // since SDL_PollEvent() is global but we poll events per window.
-        const auto results = Core::System::GetInstance().GetAndResetPerfStats();
+        SDL_PushEvent(&e);
-        const auto title =
+    }
-            fmt::format("Citra {} | {}-{} | FPS: {:.0f} ({:.0f}%)", Common::g_build_fullname,
+    if (!is_secondary) {
-                        Common::g_scm_branch, Common::g_scm_desc, results.game_fps,
+        UpdateFramerateCounter();
-                        results.emulation_speed * 100.0f);
-        SDL_SetWindowTitle(render_window, title.c_str());
-        last_time = current_time;
     }
 }
 
@@ -323,3 +323,16 @@ void EmuWindow_SDL2::DoneCurrent() {
 void EmuWindow_SDL2::OnMinimalClientAreaChangeRequest(std::pair<u32, u32> minimal_size) {
     SDL_SetWindowMinimumSize(render_window, minimal_size.first, minimal_size.second);
 }
+
+void EmuWindow_SDL2::UpdateFramerateCounter() {
+    const u32 current_time = SDL_GetTicks();
+    if (current_time > last_time + 2000) {
+        const auto results = Core::System::GetInstance().GetAndResetPerfStats();
+        const auto title =
+            fmt::format("Citra {} | {}-{} | FPS: {:.0f} ({:.0f}%)", Common::g_build_fullname,
+                        Common::g_scm_branch, Common::g_scm_desc, results.game_fps,
+                        results.emulation_speed * 100.0f);
+        SDL_SetWindowTitle(render_window, title.c_str());
+        last_time = current_time;
+    }
+}

src/citra/emu_window/emu_window_sdl2.h

@@ -29,9 +29,11 @@ private:
 
 class EmuWindow_SDL2 : public Frontend::EmuWindow {
 public:
-    explicit EmuWindow_SDL2(bool fullscreen);
+    explicit EmuWindow_SDL2(bool fullscreen, bool is_secondary);
     ~EmuWindow_SDL2();
 
+    static void InitializeSDL2();
+
     void Present();
 
     /// Polls window events
@@ -88,12 +90,18 @@ private:
     /// Called when a configuration change affects the minimal size of the window
     void OnMinimalClientAreaChangeRequest(std::pair<u32, u32> minimal_size) override;
 
+    /// Called when polling to update framerate
+    void UpdateFramerateCounter();
+
     /// Is the window still open?
     bool is_open = true;
 
     /// Internal SDL2 render window
     SDL_Window* render_window;
 
+    /// Internal SDL2 window ID
+    int render_window_id{};
+
     /// Fake hidden window for the core context
     SDL_Window* dummy_window;
 

src/citra_qt/bootmanager.cpp

@@ -113,9 +113,10 @@ void EmuThread::run() {
 #endif
 }
 
-OpenGLWindow::OpenGLWindow(QWindow* parent, QWidget* event_handler, QOpenGLContext* shared_context)
+OpenGLWindow::OpenGLWindow(QWindow* parent, QWidget* event_handler, QOpenGLContext* shared_context,
+                           bool is_secondary)
     : QWindow(parent), context(std::make_unique<QOpenGLContext>(shared_context->parent())),
-      event_handler(event_handler) {
+      event_handler(event_handler), is_secondary{is_secondary} {
 
     // disable vsync for any shared contexts
     auto format = shared_context->format();
@@ -143,7 +144,7 @@ void OpenGLWindow::Present() {
 
     context->makeCurrent(this);
     if (VideoCore::g_renderer) {
-        VideoCore::g_renderer->TryPresent(100);
+        VideoCore::g_renderer->TryPresent(100, is_secondary);
     }
     context->swapBuffers(this);
     auto f = context->versionFunctions<QOpenGLFunctions_4_3_Core>();
@@ -196,8 +197,8 @@ void OpenGLWindow::exposeEvent(QExposeEvent* event) {
     QWindow::exposeEvent(event);
 }
 
-GRenderWindow::GRenderWindow(QWidget* parent_, EmuThread* emu_thread)
+GRenderWindow::GRenderWindow(QWidget* parent_, EmuThread* emu_thread, bool is_secondary_)
-    : QWidget(parent_), emu_thread(emu_thread) {
+    : QWidget(parent_), EmuWindow(is_secondary_), emu_thread(emu_thread) {
 
     setWindowTitle(QStringLiteral("Citra %1 | %2-%3")
                        .arg(QString::fromUtf8(Common::g_build_name),
@@ -207,7 +208,6 @@ GRenderWindow::GRenderWindow(QWidget* parent_, EmuThread* emu_thread)
     auto layout = new QHBoxLayout(this);
     layout->setContentsMargins(0, 0, 0, 0);
     setLayout(layout);
-    InputCommon::Init();
 
     this->setMouseTracking(true);
 
@@ -215,9 +215,7 @@ GRenderWindow::GRenderWindow(QWidget* parent_, EmuThread* emu_thread)
     connect(this, &GRenderWindow::FirstFrameDisplayed, parent, &GMainWindow::OnLoadComplete);
 }
 
-GRenderWindow::~GRenderWindow() {
+GRenderWindow::~GRenderWindow() = default;
-    InputCommon::Shutdown();
-}
 
 void GRenderWindow::MakeCurrent() {
     core_context->MakeCurrent();
@@ -382,6 +380,12 @@ bool GRenderWindow::event(QEvent* event) {
 void GRenderWindow::focusOutEvent(QFocusEvent* event) {
     QWidget::focusOutEvent(event);
     InputCommon::GetKeyboard()->ReleaseAllKeys();
+    has_focus = false;
+}
+
+void GRenderWindow::focusInEvent(QFocusEvent* event) {
+    QWidget::focusInEvent(event);
+    has_focus = true;
 }
 
 void GRenderWindow::resizeEvent(QResizeEvent* event) {
@@ -396,7 +400,8 @@ void GRenderWindow::InitRenderTarget() {
 
     GMainWindow* parent = GetMainWindow();
     QWindow* parent_win_handle = parent ? parent->windowHandle() : nullptr;
-    child_window = new OpenGLWindow(parent_win_handle, this, QOpenGLContext::globalShareContext());
+    child_window = new OpenGLWindow(parent_win_handle, this, QOpenGLContext::globalShareContext(),
+                                    is_secondary);
     child_window->create();
     child_widget = createWindowContainer(child_window, this);
     child_widget->resize(Core::kScreenTopWidth, Core::kScreenTopHeight + Core::kScreenBottomHeight);
@@ -421,7 +426,7 @@ void GRenderWindow::ReleaseRenderTarget() {
 void GRenderWindow::CaptureScreenshot(u32 res_scale, const QString& screenshot_path) {
     if (res_scale == 0)
         res_scale = VideoCore::GetResolutionScaleFactor();
-    const Layout::FramebufferLayout layout{Layout::FrameLayoutFromResolutionScale(res_scale)};
+    const auto layout{Layout::FrameLayoutFromResolutionScale(res_scale, is_secondary)};
     screenshot_image = QImage(QSize(layout.width, layout.height), QImage::Format_RGB32);
     VideoCore::RequestScreenshot(
         screenshot_image.bits(),

src/citra_qt/bootmanager.h

@@ -129,7 +129,8 @@ signals:
 class OpenGLWindow : public QWindow {
     Q_OBJECT
 public:
-    explicit OpenGLWindow(QWindow* parent, QWidget* event_handler, QOpenGLContext* shared_context);
+    explicit OpenGLWindow(QWindow* parent, QWidget* event_handler, QOpenGLContext* shared_context,
+                          bool is_secondary = false);
 
     ~OpenGLWindow();
 
@@ -142,13 +143,14 @@ protected:
 private:
     std::unique_ptr<QOpenGLContext> context;
     QWidget* event_handler;
+    bool is_secondary;
 };
 
 class GRenderWindow : public QWidget, public Frontend::EmuWindow {
     Q_OBJECT
 
 public:
-    GRenderWindow(QWidget* parent, EmuThread* emu_thread);
+    GRenderWindow(QWidget* parent, EmuThread* emu_thread, bool is_secondary);
     ~GRenderWindow() override;
 
     // EmuWindow implementation.
@@ -178,6 +180,10 @@ public:
     bool event(QEvent* event) override;
 
     void focusOutEvent(QFocusEvent* event) override;
+    void focusInEvent(QFocusEvent* event) override;
+    bool HasFocus() const {
+        return has_focus;
+    }
 
     void InitRenderTarget();
 
@@ -229,6 +235,7 @@ private:
     /// Temporary storage of the screenshot taken
     QImage screenshot_image;
     bool first_frame = false;
+    bool has_focus = false;
 
 protected:
     void showEvent(QShowEvent* event) override;

src/citra_qt/configuration/configure_enhancements.ui

@@ -261,6 +261,11 @@
             <string>Side by Side</string>
            </property>
           </item>
+          <item>
+           <property name="text">
+            <string>Separate Windows</string>
+           </property>
+          </item>
          </widget>
         </item>
        </layout>

src/citra_qt/main.cpp

@@ -87,6 +87,7 @@
 #include "core/savestate.h"
 #include "core/settings.h"
 #include "game_list_p.h"
+#include "input_common/main.h"
 #include "network/network_settings.h"
 #include "ui_main.h"
 #include "video_core/renderer_base.h"
@@ -256,8 +257,11 @@ void GMainWindow::InitializeWidgets() {
 #ifdef CITRA_ENABLE_COMPATIBILITY_REPORTING
     ui->action_Report_Compatibility->setVisible(true);
 #endif
-    render_window = new GRenderWindow(this, emu_thread.get());
+    render_window = new GRenderWindow(this, emu_thread.get(), false);
+    secondary_window = new GRenderWindow(this, emu_thread.get(), true);
     render_window->hide();
+    secondary_window->hide();
+    secondary_window->setParent(nullptr);
 
     game_list = new GameList(this);
     ui->horizontalLayout->addWidget(game_list);
@@ -277,6 +281,7 @@ void GMainWindow::InitializeWidgets() {
         }
     });
 
+    InputCommon::Init();
     multiplayer_state = new MultiplayerState(this, game_list->GetModel(), ui->action_Leave_Room,
                                              ui->action_Show_Room);
     multiplayer_state->setVisible(false);
@@ -327,6 +332,7 @@ void GMainWindow::InitializeWidgets() {
     actionGroup_ScreenLayouts->addAction(ui->action_Screen_Layout_Single_Screen);
     actionGroup_ScreenLayouts->addAction(ui->action_Screen_Layout_Large_Screen);
     actionGroup_ScreenLayouts->addAction(ui->action_Screen_Layout_Side_by_Side);
+    actionGroup_ScreenLayouts->addAction(ui->action_Screen_Layout_Separate_Windows);
 }
 
 void GMainWindow::InitializeDebugWidgets() {
@@ -516,6 +522,17 @@ void GMainWindow::InitializeHotkeys() {
             &QShortcut::activated, ui->action_Fullscreen, &QAction::trigger);
     connect(hotkey_registry.GetHotkey(main_window, fullscreen, render_window),
             &QShortcut::activatedAmbiguously, ui->action_Fullscreen, &QAction::trigger);
+
+    // This action will fire specifically when secondary_window is in focus
+    QAction* secondary_fullscreen_action = new QAction(secondary_window);
+    // Use the same fullscreen hotkey as the main window
+    const auto fullscreen_hotkey = hotkey_registry.GetKeySequence(main_window, fullscreen);
+    secondary_fullscreen_action->setShortcut(fullscreen_hotkey);
+
+    connect(secondary_fullscreen_action, SIGNAL(triggered()), this,
+            SLOT(ToggleSecondaryFullscreen()));
+    secondary_window->addAction(secondary_fullscreen_action);
+
     connect(hotkey_registry.GetHotkey(main_window, QStringLiteral("Exit Fullscreen"), this),
             &QShortcut::activated, this, [&] {
                 if (emulation_running) {
@@ -690,6 +707,10 @@ void GMainWindow::ConnectWidgetEvents() {
             &GRenderWindow::OnEmulationStarting);
     connect(this, &GMainWindow::EmulationStopping, render_window,
             &GRenderWindow::OnEmulationStopping);
+    connect(this, &GMainWindow::EmulationStarting, secondary_window,
+            &GRenderWindow::OnEmulationStarting);
+    connect(this, &GMainWindow::EmulationStopping, secondary_window,
+            &GRenderWindow::OnEmulationStopping);
 
     connect(&status_bar_update_timer, &QTimer::timeout, this, &GMainWindow::UpdateStatusBar);
 
@@ -763,6 +784,8 @@ void GMainWindow::ConnectMenuEvents() {
             &GMainWindow::ChangeScreenLayout);
     connect(ui->action_Screen_Layout_Side_by_Side, &QAction::triggered, this,
             &GMainWindow::ChangeScreenLayout);
+    connect(ui->action_Screen_Layout_Separate_Windows, &QAction::triggered, this,
+            &GMainWindow::ChangeScreenLayout);
     connect(ui->action_Screen_Layout_Swap_Screens, &QAction::triggered, this,
             &GMainWindow::OnSwapScreens);
     connect(ui->action_Screen_Layout_Upright_Screens, &QAction::triggered, this,
@@ -922,6 +945,7 @@ bool GMainWindow::LoadROM(const QString& filename) {
         ShutdownGame();
 
     render_window->InitRenderTarget();
+    secondary_window->InitRenderTarget();
 
     Frontend::ScopeAcquireContext scope(*render_window);
 
@@ -936,7 +960,8 @@ bool GMainWindow::LoadROM(const QString& filename) {
 
     Core::System& system{Core::System::GetInstance()};
 
-    const Core::System::ResultStatus result{system.Load(*render_window, filename.toStdString())};
+    const Core::System::ResultStatus result{
+        system.Load(*render_window, filename.toStdString(), secondary_window)};
 
     if (result != Core::System::ResultStatus::Success) {
         switch (result) {
@@ -1098,6 +1123,8 @@ void GMainWindow::BootGame(const QString& filename) {
 
     connect(render_window, &GRenderWindow::Closed, this, &GMainWindow::OnStopGame);
     connect(render_window, &GRenderWindow::MouseActivity, this, &GMainWindow::OnMouseActivity);
+    connect(secondary_window, &GRenderWindow::Closed, this, &GMainWindow::OnStopGame);
+    connect(secondary_window, &GRenderWindow::MouseActivity, this, &GMainWindow::OnMouseActivity);
 
     // BlockingQueuedConnection is important here, it makes sure we've finished refreshing our views
     // before the CPU continues
@@ -1189,6 +1216,7 @@ void GMainWindow::ShutdownGame() {
 
     // The emulation is stopped, so closing the window or not does not matter anymore
     disconnect(render_window, &GRenderWindow::Closed, this, &GMainWindow::OnStopGame);
+    disconnect(secondary_window, &GRenderWindow::Closed, this, &GMainWindow::OnStopGame);
 
     // Update the GUI
     ui->action_Start->setEnabled(false);
@@ -1203,6 +1231,7 @@ void GMainWindow::ShutdownGame() {
     ui->action_Advance_Frame->setEnabled(false);
     ui->action_Capture_Screenshot->setEnabled(false);
     render_window->hide();
+    secondary_window->hide();
     loading_screen->hide();
     loading_screen->Clear();
     if (game_list->IsEmpty())
@@ -1236,6 +1265,7 @@ void GMainWindow::ShutdownGame() {
 
     // When closing the game, destroy the GLWindow to clear the context after the game is closed
     render_window->ReleaseRenderTarget();
+    secondary_window->ReleaseRenderTarget();
 }
 
 void GMainWindow::StoreRecentFile(const QString& filename) {
@@ -1636,6 +1666,7 @@ void GMainWindow::OnStopGame() {
 
 void GMainWindow::OnLoadComplete() {
     loading_screen->OnLoadComplete();
+    UpdateSecondaryWindowVisibility();
 }
 
 void GMainWindow::OnMenuReportCompatibility() {
@@ -1660,6 +1691,17 @@ void GMainWindow::ToggleFullscreen() {
     }
 }
 
+void GMainWindow::ToggleSecondaryFullscreen() {
+    if (!emulation_running) {
+        return;
+    }
+    if (secondary_window->isFullScreen()) {
+        secondary_window->showNormal();
+    } else {
+        secondary_window->showFullScreen();
+    }
+}
+
 void GMainWindow::ShowFullscreen() {
     if (ui->action_Single_Window_Mode->isChecked()) {
         UISettings::values.geometry = saveGeometry();
@@ -1709,6 +1751,19 @@ void GMainWindow::ToggleWindowMode() {
     }
 }
 
+void GMainWindow::UpdateSecondaryWindowVisibility() {
+    if (!emulation_running) {
+        return;
+    }
+    if (Settings::values.layout_option == Settings::LayoutOption::SeparateWindows) {
+        secondary_window->RestoreGeometry();
+        secondary_window->show();
+    } else {
+        secondary_window->BackupGeometry();
+        secondary_window->hide();
+    }
+}
+
 void GMainWindow::ChangeScreenLayout() {
     Settings::LayoutOption new_layout = Settings::LayoutOption::Default;
 
@@ -1720,35 +1775,38 @@ void GMainWindow::ChangeScreenLayout() {
         new_layout = Settings::LayoutOption::LargeScreen;
     } else if (ui->action_Screen_Layout_Side_by_Side->isChecked()) {
         new_layout = Settings::LayoutOption::SideScreen;
+    } else if (ui->action_Screen_Layout_Separate_Windows->isChecked()) {
+        new_layout = Settings::LayoutOption::SeparateWindows;
     }
 
     Settings::values.layout_option = new_layout;
     Settings::Apply();
+    UpdateSecondaryWindowVisibility();
 }
 
 void GMainWindow::ToggleScreenLayout() {
-    Settings::LayoutOption new_layout = Settings::LayoutOption::Default;
+    const Settings::LayoutOption new_layout = []() {
-
+        switch (Settings::values.layout_option) {
-    switch (Settings::values.layout_option) {
+        case Settings::LayoutOption::Default:
-    case Settings::LayoutOption::Default:
+            return Settings::LayoutOption::SingleScreen;
-        new_layout = Settings::LayoutOption::SingleScreen;
+        case Settings::LayoutOption::SingleScreen:
-        break;
+            return Settings::LayoutOption::LargeScreen;
-    case Settings::LayoutOption::SingleScreen:
+        case Settings::LayoutOption::LargeScreen:
-        new_layout = Settings::LayoutOption::LargeScreen;
+            return Settings::LayoutOption::SideScreen;
-        break;
+        case Settings::LayoutOption::SideScreen:
-    case Settings::LayoutOption::LargeScreen:
+            return Settings::LayoutOption::SeparateWindows;
-        new_layout = Settings::LayoutOption::SideScreen;
+        case Settings::LayoutOption::SeparateWindows:
-        break;
+            return Settings::LayoutOption::Default;
-    case Settings::LayoutOption::SideScreen:
+        default:
-        new_layout = Settings::LayoutOption::Default;
+            LOG_ERROR(Frontend, "Unknown layout option {}", Settings::values.layout_option);
-        break;
+            return Settings::LayoutOption::Default;
-    default:
+        }
-        LOG_ERROR(Frontend, "Unknown layout option {}", Settings::values.layout_option);
+    }();
-    }
 
     Settings::values.layout_option = new_layout;
     SyncMenuUISettings();
     Settings::Apply();
+    UpdateSecondaryWindowVisibility();
 }
 
 void GMainWindow::OnSwapScreens() {
@@ -1813,6 +1871,7 @@ void GMainWindow::OnConfigure() {
         } else {
             setMouseTracking(false);
         }
+        UpdateSecondaryWindowVisibility();
     } else {
         Settings::values.input_profiles = old_input_profiles;
         Settings::values.touch_from_button_maps = old_touch_from_button_maps;
@@ -1991,7 +2050,9 @@ void GMainWindow::OnCaptureScreenshot() {
     const QString timestamp =
         QDateTime::currentDateTime().toString(QStringLiteral("dd.MM.yy_hh.mm.ss.z"));
     path.append(QStringLiteral("/%1_%2.png").arg(filename, timestamp));
-    render_window->CaptureScreenshot(UISettings::values.screenshot_resolution_factor, path);
+
+    auto* const screenshot_window = secondary_window->HasFocus() ? secondary_window : render_window;
+    screenshot_window->CaptureScreenshot(UISettings::values.screenshot_resolution_factor, path);
     OnStartGame();
 }
 
@@ -2227,7 +2288,9 @@ void GMainWindow::closeEvent(QCloseEvent* event) {
         ShutdownGame();
 
     render_window->close();
+    secondary_window->close();
     multiplayer_state->Close();
+    InputCommon::Shutdown();
     QWidget::closeEvent(event);
 }
 
@@ -2412,6 +2475,8 @@ void GMainWindow::SyncMenuUISettings() {
                                                       Settings::LayoutOption::LargeScreen);
     ui->action_Screen_Layout_Side_by_Side->setChecked(Settings::values.layout_option ==
                                                       Settings::LayoutOption::SideScreen);
+    ui->action_Screen_Layout_Separate_Windows->setChecked(Settings::values.layout_option ==
+                                                          Settings::LayoutOption::SeparateWindows);
     ui->action_Screen_Layout_Swap_Screens->setChecked(Settings::values.swap_screen);
     ui->action_Screen_Layout_Upright_Screens->setChecked(Settings::values.upright_screen);
 }

src/citra_qt/main.h

@@ -197,7 +197,9 @@ private slots:
     void OnDisplayTitleBars(bool);
     void InitializeHotkeys();
     void ToggleFullscreen();
+    void ToggleSecondaryFullscreen();
     void ChangeScreenLayout();
+    void UpdateSecondaryWindowVisibility();
     void ToggleScreenLayout();
     void OnSwapScreens();
     void OnRotateScreens();
@@ -238,6 +240,7 @@ private:
     std::unique_ptr<Ui::MainWindow> ui;
 
     GRenderWindow* render_window;
+    GRenderWindow* secondary_window;
 
     GameListPlaceholder* game_list_placeholder;
     LoadingScreen* loading_screen;

src/citra_qt/main.ui

@@ -125,6 +125,7 @@
      <addaction name="action_Screen_Layout_Single_Screen"/>
      <addaction name="action_Screen_Layout_Large_Screen"/>
      <addaction name="action_Screen_Layout_Side_by_Side"/>
+     <addaction name="action_Screen_Layout_Separate_Windows"/>
      <addaction name="separator"/>
      <addaction name="action_Screen_Layout_Upright_Screens"/>
      <addaction name="action_Screen_Layout_Swap_Screens"/>
@@ -471,6 +472,14 @@
     <string>Side by Side</string>
    </property>
   </action>
+  <action name="action_Screen_Layout_Separate_Windows">
+   <property name="checkable">
+    <bool>true</bool>
+   </property>
+   <property name="text">
+    <string>Separate Windows</string>
+   </property>
+  </action>
   <action name="action_Screen_Layout_Swap_Screens">
    <property name="checkable">
     <bool>true</bool>

src/core/core.cpp

@@ -247,7 +247,8 @@ System::ResultStatus System::SingleStep() {
     return RunLoop(false);
 }
 
-System::ResultStatus System::Load(Frontend::EmuWindow& emu_window, const std::string& filepath) {
+System::ResultStatus System::Load(Frontend::EmuWindow& emu_window, const std::string& filepath,
+                                  Frontend::EmuWindow* secondary_window) {
     FileUtil::SetCurrentRomPath(filepath);
     app_loader = Loader::GetLoader(filepath);
     if (!app_loader) {
@@ -278,7 +279,8 @@ System::ResultStatus System::Load(Frontend::EmuWindow& emu_window, const std::st
     if (Settings::values.is_new_3ds) {
         num_cores = 4;
     }
-    ResultStatus init_result{Init(emu_window, *system_mode.first, *n3ds_mode.first, num_cores)};
+    ResultStatus init_result{
+        Init(emu_window, secondary_window, *system_mode.first, *n3ds_mode.first, num_cores)};
     if (init_result != ResultStatus::Success) {
         LOG_CRITICAL(Core, "Failed to initialize system (Error {})!",
                      static_cast<u32>(init_result));
@@ -324,6 +326,7 @@ System::ResultStatus System::Load(Frontend::EmuWindow& emu_window, const std::st
 
     status = ResultStatus::Success;
     m_emu_window = &emu_window;
+    m_secondary_window = secondary_window;
     m_filepath = filepath;
     self_delete_pending = false;
 
@@ -355,8 +358,9 @@ void System::Reschedule() {
     }
 }
 
-System::ResultStatus System::Init(Frontend::EmuWindow& emu_window, u32 system_mode, u8 n3ds_mode,
+System::ResultStatus System::Init(Frontend::EmuWindow& emu_window,
-                                  u32 num_cores) {
+                                  Frontend::EmuWindow* secondary_window, u32 system_mode,
+                                  u8 n3ds_mode, u32 num_cores) {
     LOG_DEBUG(HW_Memory, "initialized OK");
 
     memory = std::make_unique<Memory::MemorySystem>();
@@ -420,7 +424,7 @@ System::ResultStatus System::Init(Frontend::EmuWindow& emu_window, u32 system_mo
     video_dumper = std::make_unique<VideoDumper::NullBackend>();
 #endif
 
-    VideoCore::ResultStatus result = VideoCore::Init(emu_window, *memory);
+    VideoCore::ResultStatus result = VideoCore::Init(emu_window, secondary_window, *memory);
     if (result != VideoCore::ResultStatus::Success) {
         switch (result) {
         case VideoCore::ResultStatus::ErrorGenericDrivers:
@@ -586,7 +590,8 @@ void System::Reset() {
     }
 
     // Reload the system with the same setting
-    [[maybe_unused]] const System::ResultStatus result = Load(*m_emu_window, m_filepath);
+    [[maybe_unused]] const System::ResultStatus result =
+        Load(*m_emu_window, m_filepath, m_secondary_window);
 
     // Restore the deliver arg.
     if (auto apt = Service::APT::GetModule(*this)) {
@@ -611,8 +616,8 @@ void System::serialize(Archive& ar, const unsigned int file_version) {
         // Re-initialize everything like it was before
         auto system_mode = this->app_loader->LoadKernelSystemMode();
         auto n3ds_mode = this->app_loader->LoadKernelN3dsMode();
-        [[maybe_unused]] const System::ResultStatus result =
+        [[maybe_unused]] const System::ResultStatus result = Init(
-            Init(*m_emu_window, *system_mode.first, *n3ds_mode.first, num_cores);
+            *m_emu_window, m_secondary_window, *system_mode.first, *n3ds_mode.first, num_cores);
     }
 
     // flush on save, don't flush on load

src/core/core.h

@@ -143,7 +143,8 @@ public:
      * @param filepath String path to the executable application to load on the host file system.
      * @returns ResultStatus code, indicating if the operation succeeded.
      */
-    [[nodiscard]] ResultStatus Load(Frontend::EmuWindow& emu_window, const std::string& filepath);
+    [[nodiscard]] ResultStatus Load(Frontend::EmuWindow& emu_window, const std::string& filepath,
+                                    Frontend::EmuWindow* secondary_window = {});
 
     /**
      * Indicates if the emulated system is powered on (all subsystems initialized and able to run an
@@ -324,8 +325,9 @@ private:
      * @param system_mode The system mode.
      * @return ResultStatus code, indicating if the operation succeeded.
      */
-    [[nodiscard]] ResultStatus Init(Frontend::EmuWindow& emu_window, u32 system_mode, u8 n3ds_mode,
+    [[nodiscard]] ResultStatus Init(Frontend::EmuWindow& emu_window,
-                                    u32 num_cores);
+                                    Frontend::EmuWindow* secondary_window, u32 system_mode,
+                                    u8 n3ds_mode, u32 num_cores);
 
     /// Reschedule the core emulation
     void Reschedule();
@@ -385,6 +387,7 @@ private:
     std::string status_details = "";
     /// Saved variables for reset
     Frontend::EmuWindow* m_emu_window;
+    Frontend::EmuWindow* m_secondary_window;
     std::string m_filepath;
     std::string m_chainloadpath;
     u64 title_id;

src/core/frontend/emu_window.cpp

@@ -4,12 +4,13 @@
 
 #include <cmath>
 #include <mutex>
-#include "core/3ds.h"
 #include "core/frontend/emu_window.h"
 #include "core/frontend/input.h"
 #include "core/settings.h"
 
 namespace Frontend {
+/// We need a global touch state that is shared across the different window instances
+static std::weak_ptr<EmuWindow::TouchState> global_touch_state;
 
 GraphicsContext::~GraphicsContext() = default;
 
@@ -45,18 +46,14 @@ private:
 };
 
 EmuWindow::EmuWindow() {
-    // TODO: Find a better place to set this.
+    CreateTouchState();
-    config.min_client_area_size =
+};
-        std::make_pair(Core::kScreenTopWidth, Core::kScreenTopHeight + Core::kScreenBottomHeight);
+
-    active_config = config;
+EmuWindow::EmuWindow(bool is_secondary_) : is_secondary{is_secondary_} {
-    touch_state = std::make_shared<TouchState>();
+    CreateTouchState();
-    Input::RegisterFactory<Input::TouchDevice>("emu_window", touch_state);
-}
-
-EmuWindow::~EmuWindow() {
-    Input::UnregisterFactory<Input::TouchDevice>("emu_window");
 }
 
+EmuWindow::~EmuWindow() = default;
 /**
  * Check if the given x/y coordinates are within the touchpad specified by the framebuffer layout
  * @param layout FramebufferLayout object describing the framebuffer size and screen positions
@@ -111,6 +108,15 @@ std::tuple<unsigned, unsigned> EmuWindow::ClipToTouchScreen(unsigned new_x, unsi
     return std::make_tuple(new_x, new_y);
 }
 
+void EmuWindow::CreateTouchState() {
+    if (touch_state = global_touch_state.lock()) {
+        return;
+    }
+    touch_state = std::make_shared<TouchState>();
+    Input::RegisterFactory<Input::TouchDevice>("emu_window", touch_state);
+    global_touch_state = touch_state;
+}
+
 bool EmuWindow::TouchPressed(unsigned framebuffer_x, unsigned framebuffer_y) {
     if (!IsWithinTouchscreen(framebuffer_layout, framebuffer_x, framebuffer_y))
         return false;
@@ -194,6 +200,12 @@ void EmuWindow::UpdateCurrentFramebufferLayout(unsigned width, unsigned height,
             layout = Layout::SideFrameLayout(width, height, Settings::values.swap_screen,
                                              Settings::values.upright_screen);
             break;
+#ifndef ANDROID
+        case Settings::LayoutOption::SeparateWindows:
+            layout = Layout::SeparateWindowsLayout(width, height, is_secondary,
+                                                   Settings::values.upright_screen);
+            break;
+#endif
         case Settings::LayoutOption::MobilePortrait:
             layout = Layout::MobilePortraitFrameLayout(width, height, Settings::values.swap_screen);
             break;

src/core/frontend/emu_window.h

@@ -7,7 +7,9 @@
 #include <memory>
 #include <tuple>
 #include <utility>
+
 #include "common/common_types.h"
+#include "core/3ds.h"
 #include "core/frontend/framebuffer_layout.h"
 
 namespace Frontend {
@@ -87,12 +89,15 @@ public:
  */
 class EmuWindow : public GraphicsContext {
 public:
+    class TouchState;
+
     /// Data structure to store emuwindow configuration
     struct WindowConfig {
         bool fullscreen = false;
         int res_width = 0;
         int res_height = 0;
-        std::pair<unsigned, unsigned> min_client_area_size;
+        std::pair<unsigned, unsigned> min_client_area_size{
+            Core::kScreenTopWidth, Core::kScreenTopHeight + Core::kScreenBottomHeight};
     };
 
     /// Polls window events
@@ -177,6 +182,7 @@ public:
 
 protected:
     EmuWindow();
+    EmuWindow(bool is_secondary);
     virtual ~EmuWindow();
 
     /**
@@ -204,6 +210,8 @@ protected:
         framebuffer_layout = layout;
     }
 
+    bool is_secondary{};
+
 private:
     /**
      * Handler called when the minimal client area was requested to be changed via SetConfig.
@@ -214,13 +222,14 @@ private:
         // By default, ignore this request and do nothing.
     }
 
+    void CreateTouchState();
+
     Layout::FramebufferLayout framebuffer_layout; ///< Current framebuffer layout
 
-    WindowConfig config;        ///< Internal configuration (changes pending for being applied in
+    WindowConfig config{};        ///< Internal configuration (changes pending for being applied in
-                                /// ProcessConfigurationChanges)
+                                  /// ProcessConfigurationChanges)
-    WindowConfig active_config; ///< Internal active configuration
+    WindowConfig active_config{}; ///< Internal active configuration
 
-    class TouchState;
     std::shared_ptr<TouchState> touch_state;
 
     /**

src/core/frontend/framebuffer_layout.cpp

@@ -342,6 +342,13 @@ FramebufferLayout SideFrameLayout(u32 width, u32 height, bool swapped, bool upri
     return res;
 }
 
+FramebufferLayout SeparateWindowsLayout(u32 width, u32 height, bool is_secondary, bool upright) {
+    // When is_secondary is true, we disable the top screen, and enable the bottom screen.
+    // The same logic is found in the SingleFrameLayout using the is_swapped bool.
+    is_secondary = Settings::values.swap_screen ? !is_secondary : is_secondary;
+    return SingleFrameLayout(width, height, is_secondary, upright);
+}
+
 FramebufferLayout CustomFrameLayout(u32 width, u32 height) {
     ASSERT(width > 0);
     ASSERT(height > 0);
@@ -360,7 +367,7 @@ FramebufferLayout CustomFrameLayout(u32 width, u32 height) {
     return res;
 }
 
-FramebufferLayout FrameLayoutFromResolutionScale(u32 res_scale) {
+FramebufferLayout FrameLayoutFromResolutionScale(u32 res_scale, bool is_secondary) {
     FramebufferLayout layout;
     if (Settings::values.custom_layout == true) {
         layout = CustomFrameLayout(
@@ -370,8 +377,13 @@ FramebufferLayout FrameLayoutFromResolutionScale(u32 res_scale) {
         int width, height;
         switch (Settings::values.layout_option) {
         case Settings::LayoutOption::SingleScreen:
+#ifndef ANDROID
+        case Settings::LayoutOption::SeparateWindows:
+#endif
+        {
+            const bool swap_screens = is_secondary || Settings::values.swap_screen;
             if (Settings::values.upright_screen) {
-                if (Settings::values.swap_screen) {
+                if (swap_screens) {
                     width = Core::kScreenBottomHeight * res_scale;
                     height = Core::kScreenBottomWidth * res_scale;
                 } else {
@@ -379,7 +391,7 @@ FramebufferLayout FrameLayoutFromResolutionScale(u32 res_scale) {
                     height = Core::kScreenTopWidth * res_scale;
                 }
             } else {
-                if (Settings::values.swap_screen) {
+                if (swap_screens) {
                     width = Core::kScreenBottomWidth * res_scale;
                     height = Core::kScreenBottomHeight * res_scale;
                 } else {
@@ -387,9 +399,10 @@ FramebufferLayout FrameLayoutFromResolutionScale(u32 res_scale) {
                     height = Core::kScreenTopHeight * res_scale;
                 }
             }
-            layout = SingleFrameLayout(width, height, Settings::values.swap_screen,
+            layout =
-                                       Settings::values.upright_screen);
+                SingleFrameLayout(width, height, swap_screens, Settings::values.upright_screen);
             break;
+        }
         case Settings::LayoutOption::LargeScreen:
             if (Settings::values.upright_screen) {
                 if (Settings::values.swap_screen) {
@@ -544,6 +557,9 @@ std::pair<unsigned, unsigned> GetMinimumSizeFromLayout(Settings::LayoutOption la
 
     switch (layout) {
     case Settings::LayoutOption::SingleScreen:
+#ifndef ANDROID
+    case Settings::LayoutOption::SeparateWindows:
+#endif
         min_width = Settings::values.swap_screen ? Core::kScreenBottomWidth : Core::kScreenTopWidth;
         min_height = Core::kScreenBottomHeight;
         break;

src/core/frontend/framebuffer_layout.h

@@ -98,6 +98,16 @@ FramebufferLayout LargeFrameLayout(u32 width, u32 height, bool is_swapped, bool
  */
 FramebufferLayout SideFrameLayout(u32 width, u32 height, bool is_swapped, bool upright);
 
+/**
+ * Factory method for constructing a Frame with the Top screen and bottom
+ * screen on separate windows
+ * @param width Window framebuffer width in pixels
+ * @param height Window framebuffer height in pixels
+ * @param is_secondary if true, the bottom screen will be enabled instead of the top screen
+ * @return Newly created FramebufferLayout object with default screen regions initialized
+ */
+FramebufferLayout SeparateWindowsLayout(u32 width, u32 height, bool is_secondary, bool upright);
+
 /**
  * Factory method for constructing a custom FramebufferLayout
  * @param width Window framebuffer width in pixels
@@ -111,7 +121,7 @@ FramebufferLayout CustomFrameLayout(u32 width, u32 height);
  * Read from the current settings to determine which layout to use.
  * @param res_scale resolution scale factor
  */
-FramebufferLayout FrameLayoutFromResolutionScale(u32 res_scale);
+FramebufferLayout FrameLayoutFromResolutionScale(u32 res_scale, bool is_secondary = false);
 
 /**
  * Convenience method for transforming a frame layout when using Cardboard VR

src/core/settings.h

@@ -24,7 +24,9 @@ enum class LayoutOption {
     SingleScreen,
     LargeScreen,
     SideScreen,
-
+#ifndef ANDROID
+    SeparateWindows,
+#endif
     // Similiar to default, but better for mobile devices in portrait mode. Top screen in clamped to
     // the top of the frame, and the bottom screen is enlarged to match the top screen.
     MobilePortrait,

src/input_common/main.cpp

@@ -56,6 +56,7 @@ void Shutdown() {
     Input::UnregisterFactory<Input::AnalogDevice>("analog_from_button");
     Input::UnregisterFactory<Input::MotionDevice>("motion_emu");
     motion_emu.reset();
+    Input::UnregisterFactory<Input::TouchDevice>("emu_window");
     Input::UnregisterFactory<Input::TouchDevice>("touch_from_button");
     sdl.reset();
     udp.reset();

src/video_core/renderer_base.cpp

@@ -9,11 +9,20 @@
 #include "video_core/swrasterizer/swrasterizer.h"
 #include "video_core/video_core.h"
 
-RendererBase::RendererBase(Frontend::EmuWindow& window) : render_window{window} {}
+RendererBase::RendererBase(Frontend::EmuWindow& window, Frontend::EmuWindow* secondary_window_)
+    : render_window{window}, secondary_window{secondary_window_} {}
+
 RendererBase::~RendererBase() = default;
+
 void RendererBase::UpdateCurrentFramebufferLayout(bool is_portrait_mode) {
-    const Layout::FramebufferLayout& layout = render_window.GetFramebufferLayout();
+    const auto update_layout = [is_portrait_mode](Frontend::EmuWindow& window) {
-    render_window.UpdateCurrentFramebufferLayout(layout.width, layout.height, is_portrait_mode);
+        const Layout::FramebufferLayout& layout = window.GetFramebufferLayout();
+        window.UpdateCurrentFramebufferLayout(layout.width, layout.height, is_portrait_mode);
+    };
+    update_layout(render_window);
+    if (secondary_window) {
+        update_layout(*secondary_window);
+    }
 }
 
 void RendererBase::RefreshRasterizerSetting() {

src/video_core/renderer_base.h

@@ -15,7 +15,7 @@ class EmuWindow;
 
 class RendererBase : NonCopyable {
 public:
-    explicit RendererBase(Frontend::EmuWindow& window);
+    explicit RendererBase(Frontend::EmuWindow& window, Frontend::EmuWindow* secondary_window);
     virtual ~RendererBase();
 
     /// Initialize the renderer
@@ -29,7 +29,10 @@ public:
 
     /// Draws the latest frame to the window waiting timeout_ms for a frame to arrive (Renderer
     /// specific implementation)
-    virtual void TryPresent(int timeout_ms) = 0;
+    virtual void TryPresent(int timeout_ms, bool is_secondary) = 0;
+    virtual void TryPresent(int timeout_ms) {
+        TryPresent(timeout_ms, false);
+    }
 
     /// Prepares for video dumping (e.g. create necessary buffers, etc)
     virtual void PrepareVideoDumping() = 0;
@@ -67,7 +70,8 @@ public:
     void Sync();
 
 protected:
-    Frontend::EmuWindow& render_window; ///< Reference to the render window handle.
+    Frontend::EmuWindow& render_window;    ///< Reference to the render window handle.
+    Frontend::EmuWindow* secondary_window; ///< Reference to the secondary render window handle.
     std::unique_ptr<VideoCore::RasterizerInterface> rasterizer;
     f32 m_current_fps = 0.0f; ///< Current framerate, should be set by the renderer
     int m_current_frame = 0;  ///< Current frame, should be set by the renderer

src/video_core/renderer_opengl/renderer_opengl.cpp

@@ -352,10 +352,13 @@ static std::array<GLfloat, 3 * 2> MakeOrthographicMatrix(const float width, cons
     return matrix;
 }
 
-RendererOpenGL::RendererOpenGL(Frontend::EmuWindow& window)
+RendererOpenGL::RendererOpenGL(Frontend::EmuWindow& window, Frontend::EmuWindow* secondary_window)
-    : RendererBase{window}, frame_dumper(Core::System::GetInstance().VideoDumper(), window) {
+    : RendererBase{window, secondary_window},
-
+      frame_dumper(Core::System::GetInstance().VideoDumper(), window) {
     window.mailbox = std::make_unique<OGLTextureMailbox>();
+    if (secondary_window) {
+        secondary_window->mailbox = std::make_unique<OGLTextureMailbox>();
+    }
     frame_dumper.mailbox = std::make_unique<OGLVideoDumpingMailbox>();
 }
 
@@ -374,9 +377,17 @@ void RendererOpenGL::SwapBuffers() {
 
     RenderScreenshot();
 
-    const auto& layout = render_window.GetFramebufferLayout();
+    const auto& main_layout = render_window.GetFramebufferLayout();
-    RenderToMailbox(layout, render_window.mailbox, false);
+    RenderToMailbox(main_layout, render_window.mailbox, false);
 
+#ifndef ANDROID
+    if (Settings::values.layout_option == Settings::LayoutOption::SeparateWindows) {
+        ASSERT(secondary_window);
+        const auto& secondary_layout = secondary_window->GetFramebufferLayout();
+        RenderToMailbox(secondary_layout, secondary_window->mailbox, false);
+        secondary_window->PollEvents();
+    }
+#endif
     if (frame_dumper.IsDumping()) {
         try {
             RenderToMailbox(frame_dumper.GetLayout(), frame_dumper.mailbox, true);
@@ -1112,9 +1123,10 @@ void RendererOpenGL::DrawScreens(const Layout::FramebufferLayout& layout, bool f
     }
 }
 
-void RendererOpenGL::TryPresent(int timeout_ms) {
+void RendererOpenGL::TryPresent(int timeout_ms, bool is_secondary) {
-    const auto& layout = render_window.GetFramebufferLayout();
+    const auto& window = is_secondary ? *secondary_window : render_window;
-    auto frame = render_window.mailbox->TryGetPresentFrame(timeout_ms);
+    const auto& layout = window.GetFramebufferLayout();
+    auto frame = window.mailbox->TryGetPresentFrame(timeout_ms);
     if (!frame) {
         LOG_DEBUG(Render_OpenGL, "TryGetPresentFrame returned no frame to present");
         return;
@@ -1127,7 +1139,7 @@ void RendererOpenGL::TryPresent(int timeout_ms) {
     // Recreate the presentation FBO if the color attachment was changed
     if (frame->color_reloaded) {
         LOG_DEBUG(Render_OpenGL, "Reloading present frame");
-        render_window.mailbox->ReloadPresentFrame(frame, layout.width, layout.height);
+        window.mailbox->ReloadPresentFrame(frame, layout.width, layout.height);
     }
     glWaitSync(frame->render_fence, 0, GL_TIMEOUT_IGNORED);
     // INTEL workaround.

src/video_core/renderer_opengl/renderer_opengl.h

@@ -56,7 +56,7 @@ struct PresentationTexture {
 
 class RendererOpenGL : public RendererBase {
 public:
-    explicit RendererOpenGL(Frontend::EmuWindow& window);
+    explicit RendererOpenGL(Frontend::EmuWindow& window, Frontend::EmuWindow* secondary_window);
     ~RendererOpenGL() override;
 
     /// Initialize the renderer
@@ -70,7 +70,7 @@ public:
 
     /// Draws the latest frame from texture mailbox to the currently bound draw framebuffer in this
     /// context
-    void TryPresent(int timeout_ms) override;
+    void TryPresent(int timeout_ms, bool is_secondary) override;
 
     /// Prepares for video dumping (e.g. create necessary buffers, etc)
     void PrepareVideoDumping() override;

src/video_core/video_core.cpp

@@ -39,13 +39,14 @@ Layout::FramebufferLayout g_screenshot_framebuffer_layout;
 Memory::MemorySystem* g_memory;
 
 /// Initialize the video core
-ResultStatus Init(Frontend::EmuWindow& emu_window, Memory::MemorySystem& memory) {
+ResultStatus Init(Frontend::EmuWindow& emu_window, Frontend::EmuWindow* secondary_window,
+                  Memory::MemorySystem& memory) {
     g_memory = &memory;
     Pica::Init();
 
     OpenGL::GLES = Settings::values.use_gles;
 
-    g_renderer = std::make_unique<OpenGL::RendererOpenGL>(emu_window);
+    g_renderer = std::make_unique<OpenGL::RendererOpenGL>(emu_window, secondary_window);
     ResultStatus result = g_renderer->Init();
 
     if (result != ResultStatus::Success) {

src/video_core/video_core.h

@@ -54,7 +54,8 @@ enum class ResultStatus {
 };
 
 /// Initialize the video core
-ResultStatus Init(Frontend::EmuWindow& emu_window, Memory::MemorySystem& memory);
+ResultStatus Init(Frontend::EmuWindow& emu_window, Frontend::EmuWindow* secondary_window,
+                  Memory::MemorySystem& memory);
 
 /// Shutdown the video core
 void Shutdown();