init the renderer on demand, instead of always ready

src/qt/qt_mainwindow.cpp

@@ -55,8 +55,6 @@ MainWindow::MainWindow(QWidget *parent) :
 
     ui->setupUi(this);
     ui->stackedWidget->setMouseTracking(true);
-    ui->ogl->setRenderType(HardwareRenderer::RenderType::OpenGL);
-    ui->gles->setRenderType(HardwareRenderer::RenderType::OpenGLES);
     statusBar()->setVisible(!hide_status_bar);
 
     this->setWindowIcon(QIcon(":/settings/win/icons/86Box-yellow.ico"));
@@ -138,15 +136,15 @@ MainWindow::MainWindow(QWidget *parent) :
     ui->actionUpdate_status_bar_icons->setChecked(update_icons);
     switch (vid_api) {
     case 0:
-        ui->stackedWidget->setCurrentIndex(0);
+        ui->stackedWidget->switchRenderer(RendererStack::Renderer::Software);
         ui->actionSoftware_Renderer->setChecked(true);
         break;
     case 1:
-        ui->stackedWidget->setCurrentIndex(1);
+        ui->stackedWidget->switchRenderer(RendererStack::Renderer::OpenGL);
         ui->actionHardware_Renderer_OpenGL->setChecked(true);
         break;
     case 2:
-        ui->stackedWidget->setCurrentIndex(2);
+        ui->stackedWidget->switchRenderer(RendererStack::Renderer::OpenGLES);
         ui->actionHardware_Renderer_OpenGL_ES->setChecked(true);
         break;
     }
@@ -225,9 +223,6 @@ MainWindow::MainWindow(QWidget *parent) :
     }
 
     setFocusPolicy(Qt::StrongFocus);
-    ui->gles->setFocusPolicy(Qt::NoFocus);
-    ui->sw->setFocusPolicy(Qt::NoFocus);
-    ui->ogl->setFocusPolicy(Qt::NoFocus);
     ui->stackedWidget->setFocusPolicy(Qt::NoFocus);
     ui->centralwidget->setFocusPolicy(Qt::NoFocus);
     menuBar()->setFocusPolicy(Qt::NoFocus);
@@ -964,21 +959,21 @@ QSize MainWindow::getRenderWidgetSize()
 }
 
 void MainWindow::on_actionSoftware_Renderer_triggered() {
-    ui->stackedWidget->setCurrentIndex(0);
+    ui->stackedWidget->switchRenderer(RendererStack::Renderer::Software);
     ui->actionHardware_Renderer_OpenGL->setChecked(false);
     ui->actionHardware_Renderer_OpenGL_ES->setChecked(false);
     vid_api = 0;
 }
 
 void MainWindow::on_actionHardware_Renderer_OpenGL_triggered() {
-    ui->stackedWidget->setCurrentIndex(1);
+    ui->stackedWidget->switchRenderer(RendererStack::Renderer::OpenGL);
     ui->actionSoftware_Renderer->setChecked(false);
     ui->actionHardware_Renderer_OpenGL_ES->setChecked(false);
     vid_api = 1;
 }
 
 void MainWindow::on_actionHardware_Renderer_OpenGL_ES_triggered() {
-    ui->stackedWidget->setCurrentIndex(2);
+    ui->stackedWidget->switchRenderer(RendererStack::Renderer::OpenGLES);
     ui->actionSoftware_Renderer->setChecked(false);
     ui->actionHardware_Renderer_OpenGL->setChecked(false);
     vid_api = 2;

src/qt/qt_mainwindow.ui

@@ -37,14 +37,7 @@
      <number>0</number>
     </property>
     <item>
-     <widget class="RendererStack" name="stackedWidget">
+     <widget class="RendererStack" name="stackedWidget" />
-      <property name="currentIndex">
-       <number>0</number>
-      </property>
-      <widget class="SoftwareRenderer" name="sw"/>
-      <widget class="HardwareRenderer" name="ogl"/>
-      <widget class="HardwareRenderer" name="gles"/>
-     </widget>
     </item>
    </layout>
   </widget>

src/qt/qt_rendererstack.cpp

@@ -162,6 +162,42 @@ void RendererStack::leaveEvent(QEvent* event)
     event->accept();
 }
 
+void RendererStack::switchRenderer(Renderer renderer) {
+    startblit();
+    if (current != nullptr) {
+        removeWidget(current);
+    }
+
+    switch (renderer) {
+    case Renderer::Software:
+    {
+        auto sw = new SoftwareRenderer(this);
+        connect(this, &RendererStack::blitToRenderer, sw, &SoftwareRenderer::onBlit);
+        current = sw;
+    }
+        break;
+    case Renderer::OpenGL:
+    {
+        auto hw = new HardwareRenderer(this);
+        connect(this, &RendererStack::blitToRenderer, hw, &HardwareRenderer::onBlit);
+        hw->setRenderType(HardwareRenderer::RenderType::OpenGL);
+        current = hw;
+        break;
+    }
+    case Renderer::OpenGLES:
+    {
+        auto hw = new HardwareRenderer(this);
+        connect(this, &RendererStack::blitToRenderer, hw, &HardwareRenderer::onBlit);
+        hw->setRenderType(HardwareRenderer::RenderType::OpenGLES);
+        current = hw;
+        break;
+    }
+    }
+    current->setFocusPolicy(Qt::NoFocus);
+    addWidget(current);
+    endblit();
+}
+
 // called from blitter thread
 void RendererStack::blit(int x, int y, int w, int h)
 {
@@ -185,16 +221,3 @@ void RendererStack::blit(int x, int y, int w, int h)
     blitToRenderer(imagebufs[currentBuf], sx, sy, sw, sh);
     currentBuf = (currentBuf + 1) % 2;
 }
-
-void RendererStack::on_RendererStack_currentChanged(int arg1) {
-    disconnect(this, &RendererStack::blitToRenderer, nullptr, nullptr);
-    switch (arg1) {
-    case 0:
-        connect(this, &RendererStack::blitToRenderer, dynamic_cast<SoftwareRenderer*>(currentWidget()), &SoftwareRenderer::onBlit);
-        break;
-    case 1:
-    case 2:
-        connect(this, &RendererStack::blitToRenderer, dynamic_cast<HardwareRenderer*>(currentWidget()), &HardwareRenderer::onBlit);
-        break;
-    }
-}

src/qt/qt_rendererstack.hpp

@@ -31,6 +31,13 @@ public:
         event->ignore();
     }
 
+    enum class Renderer {
+        Software,
+        OpenGL,
+        OpenGLES,
+    };
+    void switchRenderer(Renderer renderer);
+
 signals:
     void blitToRenderer(const QImage& img, int, int, int, int);
 
@@ -38,9 +45,6 @@ public slots:
     void blit(int x, int y, int w, int h);
     void mousePoll();
 
-private slots:
-    void on_RendererStack_currentChanged(int arg1);
-
 private:
     Ui::RendererStack *ui;
 
@@ -57,6 +61,8 @@ private:
     // when calling bits();
     int currentBuf = 0;
     QVector<QImage> imagebufs;
+
+    QWidget* current = nullptr;
 };
 
 #endif // QT_RENDERERCONTAINER_HPP