Change Present to finish only after swap

src/citra_qt/bootmanager.cpp

@@ -86,7 +86,7 @@ GRenderWindow::GRenderWindow(QWidget* parent, EmuThread* emu_thread)
     setWindowTitle(QStringLiteral("Citra %1 | %2-%3")
                        .arg(Common::g_build_name, Common::g_scm_branch, Common::g_scm_desc));
     setAttribute(Qt::WA_AcceptTouchEvents);
-
+    connect(this, &QOpenGLWidget::frameSwapped, this, &GRenderWindow::OnFrameSwapped);
     InputCommon::Init();
 }
 
@@ -104,6 +104,10 @@ void GRenderWindow::DoneCurrent() {
 
 void GRenderWindow::PollEvents() {}
 
+void OnFrameSwapped() {
+    VideoCore::g_renderer->PresentComplete();
+}
+
 // On Qt 5.0+, this correctly gets the size of the framebuffer (pixels).
 //
 // Older versions get the window size (density independent pixels),
@@ -294,6 +298,10 @@ void GRenderWindow::paintGL() {
     update();
 }
 
+void GRenderWindow::OnFrameSwapped() {
+    VideoCore::g_renderer->PresentComplete();
+}
+
 void GRenderWindow::showEvent(QShowEvent* event) {
     QWidget::showEvent(event);
 }