7 files changed, 240 insertions, 94 deletions

diff --git a/src/core/frontend/emu_window.h b/src/core/frontend/emu_window.h
index d0bcb4660..70a522556 100644
--- a/src/core/frontend/emu_window.h
+++ b/src/core/frontend/emu_window.h
@@ -13,6 +13,23 @@
 namespace Core::Frontend {
 
 /**
+ * Represents a graphics context that can be used for background computation or drawing. If the
+ * graphics backend doesn't require the context, then the implementation of these methods can be
+ * stubs
+ */
+class GraphicsContext {
+public:
+    /// Makes the graphics context current for the caller thread
+    virtual void MakeCurrent() = 0;
+
+    /// Releases (dunno if this is the "right" word) the context from the caller thread
+    virtual void DoneCurrent() = 0;
+
+    /// Swap buffers to display the next frame
+    virtual void SwapBuffers() = 0;
+};
+
+/**
  * Abstraction class used to provide an interface between emulation code and the frontend
  * (e.g. SDL, QGLWidget, GLFW, etc...).
  *
@@ -30,7 +47,7 @@ namespace Core::Frontend {
  * - DO NOT TREAT THIS CLASS AS A GUI TOOLKIT ABSTRACTION LAYER. That's not what it is. Please
  *   re-read the upper points again and think about it if you don't see this.
  */
-class EmuWindow {
+class EmuWindow : public GraphicsContext {
 public:
     /// Data structure to store emuwindow configuration
     struct WindowConfig {
@@ -40,17 +57,21 @@ public:
         std::pair<unsigned, unsigned> min_client_area_size;
     };
 
-    /// Swap buffers to display the next frame
-    virtual void SwapBuffers() = 0;
-
     /// Polls window events
     virtual void PollEvents() = 0;
 
-    /// Makes the graphics context current for the caller thread
-    virtual void MakeCurrent() = 0;
-
-    /// Releases (dunno if this is the "right" word) the GLFW context from the caller thread
-    virtual void DoneCurrent() = 0;
+    /**
+     * Returns a GraphicsContext that the frontend provides that is shared with the emu window. This
+     * context can be used from other threads for background graphics computation. If the frontend
+     * is using a graphics backend that doesn't need anything specific to run on a different thread,
+     * then it can use a stubbed implemenation for GraphicsContext.
+     *
+     * If the return value is null, then the core should assume that the frontend cannot provide a
+     * Shared Context
+     */
+    virtual std::unique_ptr<GraphicsContext> CreateSharedContext() const {
+        return nullptr;
+    }
 
     /**
      * Signal that a touch pressed event has occurred (e.g. mouse click pressed)
diff --git a/src/yuzu/bootmanager.cpp b/src/yuzu/bootmanager.cpp
index 7438fbc0a..c29f2d2dc 100644
--- a/src/yuzu/bootmanager.cpp
+++ b/src/yuzu/bootmanager.cpp
@@ -1,6 +1,13 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
 #include <QApplication>
 #include <QHBoxLayout>
 #include <QKeyEvent>
+#include <QOffscreenSurface>
+#include <QOpenGLWindow>
+#include <QPainter>
 #include <QScreen>
 #include <QWindow>
 #include <fmt/format.h>
@@ -82,13 +89,36 @@ void EmuThread::run() {
     render_window->moveContext();
 }
 
+class GGLContext : public Core::Frontend::GraphicsContext {
+public:
+    explicit GGLContext(QOpenGLContext* shared_context) : surface() {
+        context = std::make_unique<QOpenGLContext>(shared_context);
+        surface.setFormat(shared_context->format());
+        surface.create();
+    }
+
+    void MakeCurrent() override {
+        context->makeCurrent(&surface);
+    }
+
+    void DoneCurrent() override {
+        context->doneCurrent();
+    }
+
+    void SwapBuffers() override {}
+
+private:
+    std::unique_ptr<QOpenGLContext> context;
+    QOffscreenSurface surface;
+};
+
 // This class overrides paintEvent and resizeEvent to prevent the GUI thread from stealing GL
 // context.
 // The corresponding functionality is handled in EmuThread instead
-class GGLWidgetInternal : public QGLWidget {
+class GGLWidgetInternal : public QOpenGLWindow {
 public:
-    GGLWidgetInternal(QGLFormat fmt, GRenderWindow* parent)
-        : QGLWidget(fmt, parent), parent(parent) {}
+    GGLWidgetInternal(GRenderWindow* parent, QOpenGLContext* shared_context)
+        : QOpenGLWindow(shared_context), parent(parent) {}
 
     void paintEvent(QPaintEvent* ev) override {
         if (do_painting) {
@@ -101,9 +131,51 @@ public:
         parent->OnFramebufferSizeChanged();
     }
 
+    void keyPressEvent(QKeyEvent* event) override {
+        InputCommon::GetKeyboard()->PressKey(event->key());
+    }
+
+    void keyReleaseEvent(QKeyEvent* event) override {
+        InputCommon::GetKeyboard()->ReleaseKey(event->key());
+    }
+
+    void mousePressEvent(QMouseEvent* event) override {
+        if (event->source() == Qt::MouseEventSynthesizedBySystem)
+            return; // touch input is handled in TouchBeginEvent
+
+        const auto pos{event->pos()};
+        if (event->button() == Qt::LeftButton) {
+            const auto [x, y] = parent->ScaleTouch(pos);
+            parent->TouchPressed(x, y);
+        } else if (event->button() == Qt::RightButton) {
+            InputCommon::GetMotionEmu()->BeginTilt(pos.x(), pos.y());
+        }
+    }
+
+    void mouseMoveEvent(QMouseEvent* event) override {
+        if (event->source() == Qt::MouseEventSynthesizedBySystem)
+            return; // touch input is handled in TouchUpdateEvent
+
+        const auto pos{event->pos()};
+        const auto [x, y] = parent->ScaleTouch(pos);
+        parent->TouchMoved(x, y);
+        InputCommon::GetMotionEmu()->Tilt(pos.x(), pos.y());
+    }
+
+    void mouseReleaseEvent(QMouseEvent* event) override {
+        if (event->source() == Qt::MouseEventSynthesizedBySystem)
+            return; // touch input is handled in TouchEndEvent
+
+        if (event->button() == Qt::LeftButton)
+            parent->TouchReleased();
+        else if (event->button() == Qt::RightButton)
+            InputCommon::GetMotionEmu()->EndTilt();
+    }
+
     void DisablePainting() {
         do_painting = false;
     }
+
     void EnablePainting() {
         do_painting = true;
     }
@@ -114,7 +186,7 @@ private:
 };
 
 GRenderWindow::GRenderWindow(QWidget* parent, EmuThread* emu_thread)
-    : QWidget(parent), child(nullptr), emu_thread(emu_thread) {
+    : QWidget(parent), child(nullptr), context(nullptr), emu_thread(emu_thread) {
 
     setWindowTitle(QStringLiteral("yuzu %1 | %2-%3")
                        .arg(Common::g_build_name, Common::g_scm_branch, Common::g_scm_desc));
@@ -137,19 +209,19 @@ void GRenderWindow::moveContext() {
     auto thread = (QThread::currentThread() == qApp->thread() && emu_thread != nullptr)
                       ? emu_thread
                       : qApp->thread();
-    child->context()->moveToThread(thread);
+    context->moveToThread(thread);
 }
 
 void GRenderWindow::SwapBuffers() {
-    // In our multi-threaded QGLWidget use case we shouldn't need to call `makeCurrent`,
+    // In our multi-threaded QWidget use case we shouldn't need to call `makeCurrent`,
     // since we never call `doneCurrent` in this thread.
     // However:
     // - The Qt debug runtime prints a bogus warning on the console if `makeCurrent` wasn't called
     // since the last time `swapBuffers` was executed;
     // - On macOS, if `makeCurrent` isn't called explicitely, resizing the buffer breaks.
-    child->makeCurrent();
+    context->makeCurrent(child);
 
-    child->swapBuffers();
+    context->swapBuffers(child);
     if (!first_frame) {
         emit FirstFrameDisplayed();
         first_frame = true;
@@ -157,11 +229,11 @@ void GRenderWindow::SwapBuffers() {
 }
 
 void GRenderWindow::MakeCurrent() {
-    child->makeCurrent();
+    context->makeCurrent(child);
 }
 
 void GRenderWindow::DoneCurrent() {
-    child->doneCurrent();
+    context->doneCurrent();
 }
 
 void GRenderWindow::PollEvents() {}
@@ -174,14 +246,26 @@ void GRenderWindow::PollEvents() {}
 void GRenderWindow::OnFramebufferSizeChanged() {
     // Screen changes potentially incur a change in screen DPI, hence we should update the
     // framebuffer size
-    qreal pixelRatio = windowPixelRatio();
+    qreal pixelRatio = GetWindowPixelRatio();
     unsigned width = child->QPaintDevice::width() * pixelRatio;
     unsigned height = child->QPaintDevice::height() * pixelRatio;
     UpdateCurrentFramebufferLayout(width, height);
 }
 
+void GRenderWindow::ForwardKeyPressEvent(QKeyEvent* event) {
+    if (child) {
+        child->keyPressEvent(event);
+    }
+}
+
+void GRenderWindow::ForwardKeyReleaseEvent(QKeyEvent* event) {
+    if (child) {
+        child->keyReleaseEvent(event);
+    }
+}
+
 void GRenderWindow::BackupGeometry() {
-    geometry = ((QGLWidget*)this)->saveGeometry();
+    geometry = ((QWidget*)this)->saveGeometry();
 }
 
 void GRenderWindow::RestoreGeometry() {
@@ -199,18 +283,18 @@ QByteArray GRenderWindow::saveGeometry() {
     // If we are a top-level widget, store the current geometry
     // otherwise, store the last backup
     if (parent() == nullptr)
-        return ((QGLWidget*)this)->saveGeometry();
+        return ((QWidget*)this)->saveGeometry();
     else
         return geometry;
 }
 
-qreal GRenderWindow::windowPixelRatio() const {
+qreal GRenderWindow::GetWindowPixelRatio() const {
     // windowHandle() might not be accessible until the window is displayed to screen.
     return windowHandle() ? windowHandle()->screen()->devicePixelRatio() : 1.0f;
 }
 
 std::pair<unsigned, unsigned> GRenderWindow::ScaleTouch(const QPointF pos) const {
-    const qreal pixel_ratio = windowPixelRatio();
+    const qreal pixel_ratio = GetWindowPixelRatio();
     return {static_cast<unsigned>(std::max(std::round(pos.x() * pixel_ratio), qreal{0.0})),
             static_cast<unsigned>(std::max(std::round(pos.y() * pixel_ratio), qreal{0.0}))};
 }
@@ -220,47 +304,6 @@ void GRenderWindow::closeEvent(QCloseEvent* event) {
     QWidget::closeEvent(event);
 }
 
-void GRenderWindow::keyPressEvent(QKeyEvent* event) {
-    InputCommon::GetKeyboard()->PressKey(event->key());
-}
-
-void GRenderWindow::keyReleaseEvent(QKeyEvent* event) {
-    InputCommon::GetKeyboard()->ReleaseKey(event->key());
-}
-
-void GRenderWindow::mousePressEvent(QMouseEvent* event) {
-    if (event->source() == Qt::MouseEventSynthesizedBySystem)
-        return; // touch input is handled in TouchBeginEvent
-
-    auto pos = event->pos();
-    if (event->button() == Qt::LeftButton) {
-        const auto [x, y] = ScaleTouch(pos);
-        this->TouchPressed(x, y);
-    } else if (event->button() == Qt::RightButton) {
-        InputCommon::GetMotionEmu()->BeginTilt(pos.x(), pos.y());
-    }
-}
-
-void GRenderWindow::mouseMoveEvent(QMouseEvent* event) {
-    if (event->source() == Qt::MouseEventSynthesizedBySystem)
-        return; // touch input is handled in TouchUpdateEvent
-
-    auto pos = event->pos();
-    const auto [x, y] = ScaleTouch(pos);
-    this->TouchMoved(x, y);
-    InputCommon::GetMotionEmu()->Tilt(pos.x(), pos.y());
-}
-
-void GRenderWindow::mouseReleaseEvent(QMouseEvent* event) {
-    if (event->source() == Qt::MouseEventSynthesizedBySystem)
-        return; // touch input is handled in TouchEndEvent
-
-    if (event->button() == Qt::LeftButton)
-        this->TouchReleased();
-    else if (event->button() == Qt::RightButton)
-        InputCommon::GetMotionEmu()->EndTilt();
-}
-
 void GRenderWindow::TouchBeginEvent(const QTouchEvent* event) {
     // TouchBegin always has exactly one touch point, so take the .first()
     const auto [x, y] = ScaleTouch(event->touchPoints().first().pos());
@@ -313,35 +356,60 @@ void GRenderWindow::OnClientAreaResized(unsigned width, unsigned height) {
     NotifyClientAreaSizeChanged(std::make_pair(width, height));
 }
 
+std::unique_ptr<Core::Frontend::GraphicsContext> GRenderWindow::CreateSharedContext() const {
+    return std::make_unique<GGLContext>(shared_context.get());
+}
+
 void GRenderWindow::InitRenderTarget() {
-    if (child) {
-        delete child;
-    }
+    shared_context.reset();
+    context.reset();
 
-    if (layout()) {
-        delete layout();
-    }
+    delete child;
+    child = nullptr;
+
+    delete container;
+    container = nullptr;
+
+    delete layout();
 
     first_frame = false;
 
     // TODO: One of these flags might be interesting: WA_OpaquePaintEvent, WA_NoBackground,
     // WA_DontShowOnScreen, WA_DeleteOnClose
-    QGLFormat fmt;
+    QSurfaceFormat fmt;
     fmt.setVersion(4, 3);
-    fmt.setProfile(QGLFormat::CoreProfile);
+    fmt.setProfile(QSurfaceFormat::CoreProfile);
+    // TODO: expose a setting for buffer value (ie default/single/double/triple)
+    fmt.setSwapBehavior(QSurfaceFormat::DefaultSwapBehavior);
+    shared_context = std::make_unique<QOpenGLContext>();
+    shared_context->setFormat(fmt);
+    shared_context->create();
+    context = std::make_unique<QOpenGLContext>();
+    context->setShareContext(shared_context.get());
+    context->setFormat(fmt);
+    context->create();
     fmt.setSwapInterval(false);
 
-    // Requests a forward-compatible context, which is required to get a 3.2+ context on OS X
-    fmt.setOption(QGL::NoDeprecatedFunctions);
+    child = new GGLWidgetInternal(this, shared_context.get());
+    container = QWidget::createWindowContainer(child, this);
 
-    child = new GGLWidgetInternal(fmt, this);
     QBoxLayout* layout = new QHBoxLayout(this);
-
-    resize(Layout::ScreenUndocked::Width, Layout::ScreenUndocked::Height);
-    layout->addWidget(child);
+    layout->addWidget(container);
     layout->setMargin(0);
     setLayout(layout);
 
+    // Reset minimum size to avoid unwanted resizes when this function is called for a second time.
+    setMinimumSize(1, 1);
+
+    // Show causes the window to actually be created and the OpenGL context as well, but we don't
+    // want the widget to be shown yet, so immediately hide it.
+    show();
+    hide();
+
+    resize(Layout::ScreenUndocked::Width, Layout::ScreenUndocked::Height);
+    child->resize(Layout::ScreenUndocked::Width, Layout::ScreenUndocked::Height);
+    container->resize(Layout::ScreenUndocked::Width, Layout::ScreenUndocked::Height);
+
     OnMinimalClientAreaChangeRequest(GetActiveConfig().min_client_area_size);
 
     OnFramebufferSizeChanged();
diff --git a/src/yuzu/bootmanager.h b/src/yuzu/bootmanager.h
index 3183621bc..9608b959f 100644
--- a/src/yuzu/bootmanager.h
+++ b/src/yuzu/bootmanager.h
@@ -7,9 +7,9 @@
 #include <atomic>
 #include <condition_variable>
 #include <mutex>
-#include <QGLWidget>
 #include <QImage>
 #include <QThread>
+#include <QWidget>
 #include "common/thread.h"
 #include "core/core.h"
 #include "core/frontend/emu_window.h"
@@ -21,6 +21,8 @@ class QTouchEvent;
 class GGLWidgetInternal;
 class GMainWindow;
 class GRenderWindow;
+class QSurface;
+class QOpenGLContext;
 
 namespace VideoCore {
 enum class LoadCallbackStage;
@@ -121,25 +123,21 @@ public:
     void MakeCurrent() override;
     void DoneCurrent() override;
     void PollEvents() override;
+    std::unique_ptr<Core::Frontend::GraphicsContext> CreateSharedContext() const override;
+
+    void ForwardKeyPressEvent(QKeyEvent* event);
+    void ForwardKeyReleaseEvent(QKeyEvent* event);
 
     void BackupGeometry();
     void RestoreGeometry();
     void restoreGeometry(const QByteArray& geometry); // overridden
     QByteArray saveGeometry();                        // overridden
 
-    qreal windowPixelRatio() const;
+    qreal GetWindowPixelRatio() const;
+    std::pair<unsigned, unsigned> ScaleTouch(const QPointF pos) const;
 
     void closeEvent(QCloseEvent* event) override;
-
-    void keyPressEvent(QKeyEvent* event) override;
-    void keyReleaseEvent(QKeyEvent* event) override;
-
-    void mousePressEvent(QMouseEvent* event) override;
-    void mouseMoveEvent(QMouseEvent* event) override;
-    void mouseReleaseEvent(QMouseEvent* event) override;
-
     bool event(QEvent* event) override;
-
     void focusOutEvent(QFocusEvent* event) override;
 
     void OnClientAreaResized(unsigned width, unsigned height);
@@ -161,7 +159,6 @@ signals:
     void FirstFrameDisplayed();
 
 private:
-    std::pair<unsigned, unsigned> ScaleTouch(const QPointF pos) const;
     void TouchBeginEvent(const QTouchEvent* event);
     void TouchUpdateEvent(const QTouchEvent* event);
     void TouchEndEvent();
@@ -169,11 +166,17 @@ private:
     void OnMinimalClientAreaChangeRequest(
         const std::pair<unsigned, unsigned>& minimal_size) override;
 
-    GGLWidgetInternal* child;
+    QWidget* container = nullptr;
+    GGLWidgetInternal* child = nullptr;
 
     QByteArray geometry;
 
     EmuThread* emu_thread;
+    // Context that backs the GGLWidgetInternal (and will be used by core to render)
+    std::unique_ptr<QOpenGLContext> context;
+    // Context that will be shared between all newly created contexts. This should never be made
+    // current
+    std::unique_ptr<QOpenGLContext> shared_context;
 
     /// Temporary storage of the screenshot taken
     QImage screenshot_image;
diff --git a/src/yuzu/main.cpp b/src/yuzu/main.cpp
index 588f53860..bdee44b04 100644
--- a/src/yuzu/main.cpp
+++ b/src/yuzu/main.cpp
@@ -2031,6 +2031,18 @@ void GMainWindow::dragMoveEvent(QDragMoveEvent* event) {
     event->acceptProposedAction();
 }
 
+void GMainWindow::keyPressEvent(QKeyEvent* event) {
+    if (render_window) {
+        render_window->ForwardKeyPressEvent(event);
+    }
+}
+
+void GMainWindow::keyReleaseEvent(QKeyEvent* event) {
+    if (render_window) {
+        render_window->ForwardKeyReleaseEvent(event);
+    }
+}
+
 bool GMainWindow::ConfirmChangeGame() {
     if (emu_thread == nullptr)
         return true;
@@ -2098,7 +2110,8 @@ int main(int argc, char* argv[]) {
     QCoreApplication::setOrganizationName("yuzu team");
     QCoreApplication::setApplicationName("yuzu");
 
-    QApplication::setAttribute(Qt::AA_DontCheckOpenGLContextThreadAffinity);
+    // Enables the core to make the qt created contexts current on std::threads
+    QCoreApplication::setAttribute(Qt::AA_DontCheckOpenGLContextThreadAffinity);
     QApplication app(argc, argv);
 
     // Qt changes the locale and causes issues in float conversion using std::to_string() when
diff --git a/src/yuzu/main.h b/src/yuzu/main.h
index 85e3810f2..ce5045819 100644
--- a/src/yuzu/main.h
+++ b/src/yuzu/main.h
@@ -252,4 +252,8 @@ protected:
     void dropEvent(QDropEvent* event) override;
     void dragEnterEvent(QDragEnterEvent* event) override;
     void dragMoveEvent(QDragMoveEvent* event) override;
+
+    // Overrides used to forward signals to the render window when the focus moves out.
+    void keyPressEvent(QKeyEvent* event) override;
+    void keyReleaseEvent(QKeyEvent* event) override;
 };
diff --git a/src/yuzu_cmd/emu_window/emu_window_sdl2.cpp b/src/yuzu_cmd/emu_window/emu_window_sdl2.cpp
index de7a26e14..68a176032 100644
--- a/src/yuzu_cmd/emu_window/emu_window_sdl2.cpp
+++ b/src/yuzu_cmd/emu_window/emu_window_sdl2.cpp
@@ -19,6 +19,37 @@
 #include "input_common/sdl/sdl.h"
 #include "yuzu_cmd/emu_window/emu_window_sdl2.h"
 
+class SDLGLContext : public Core::Frontend::GraphicsContext {
+public:
+    explicit SDLGLContext() {
+        // create a hidden window to make the shared context against
+        window = SDL_CreateWindow("", SDL_WINDOWPOS_UNDEFINED, // x position
+                                  SDL_WINDOWPOS_UNDEFINED,     // y position
+                                  Layout::ScreenUndocked::Width, Layout::ScreenUndocked::Height,
+                                  SDL_WINDOW_OPENGL | SDL_WINDOW_HIDDEN);
+        context = SDL_GL_CreateContext(window);
+    }
+
+    ~SDLGLContext() {
+        SDL_GL_DeleteContext(context);
+        SDL_DestroyWindow(window);
+    }
+
+    void MakeCurrent() override {
+        SDL_GL_MakeCurrent(window, context);
+    }
+
+    void DoneCurrent() override {
+        SDL_GL_MakeCurrent(window, nullptr);
+    }
+
+    void SwapBuffers() override {}
+
+private:
+    SDL_Window* window;
+    SDL_GLContext context;
+};
+
 void EmuWindow_SDL2::OnMouseMotion(s32 x, s32 y) {
     TouchMoved((unsigned)std::max(x, 0), (unsigned)std::max(y, 0));
     InputCommon::GetMotionEmu()->Tilt(x, y);
@@ -153,6 +184,7 @@ EmuWindow_SDL2::EmuWindow_SDL2(bool fullscreen) {
     SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8);
     SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8);
     SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 0);
+    SDL_GL_SetAttribute(SDL_GL_SHARE_WITH_CURRENT_CONTEXT, 1);
 
     std::string window_title = fmt::format("yuzu {} | {}-{}", Common::g_build_fullname,
                                            Common::g_scm_branch, Common::g_scm_desc);
@@ -171,7 +203,6 @@ EmuWindow_SDL2::EmuWindow_SDL2(bool fullscreen) {
     if (fullscreen) {
         Fullscreen();
     }
-
     gl_context = SDL_GL_CreateContext(render_window);
 
     if (gl_context == nullptr) {
@@ -278,3 +309,7 @@ void EmuWindow_SDL2::OnMinimalClientAreaChangeRequest(
 
     SDL_SetWindowMinimumSize(render_window, minimal_size.first, minimal_size.second);
 }
+
+std::unique_ptr<Core::Frontend::GraphicsContext> EmuWindow_SDL2::CreateSharedContext() const {
+    return std::make_unique<SDLGLContext>();
+}
diff --git a/src/yuzu_cmd/emu_window/emu_window_sdl2.h b/src/yuzu_cmd/emu_window/emu_window_sdl2.h
index b0d4116cc..17e98227f 100644
--- a/src/yuzu_cmd/emu_window/emu_window_sdl2.h
+++ b/src/yuzu_cmd/emu_window/emu_window_sdl2.h
@@ -27,6 +27,8 @@ public:
     /// Releases the GL context from the caller thread
     void DoneCurrent() override;
 
+    std::unique_ptr<Core::Frontend::GraphicsContext> CreateSharedContext() const override;
+
     /// Whether the window is still open, and a close request hasn't yet been sent
     bool IsOpen() const;