citra_qt: Add API status indicator

src/citra_qt/configuration/configure_graphics.ui

@@ -60,6 +60,11 @@
              <string>OpenGL</string>
             </property>
            </item>
+           <item>
+            <property name="text">
+             <string>Vulkan</string>
+            </property>
+           </item>
           </widget>
          </item>
         </layout>

src/citra_qt/main.cpp

@@ -357,6 +357,22 @@ void GMainWindow::InitializeWidgets() {
         statusBar()->addPermanentWidget(label);
     }
 
+    // Setup Graphics API button
+    graphics_api_button = new QPushButton();
+    graphics_api_button->setObjectName(QStringLiteral("GraphicsAPIStatusBarButton"));
+    graphics_api_button->setFocusPolicy(Qt::NoFocus);
+    UpdateAPIIndicator();
+
+    connect(graphics_api_button, &QPushButton::clicked, this, [this] {
+        if (emulation_running) {
+            return;
+        }
+
+        UpdateAPIIndicator(true);
+    });
+
+    statusBar()->insertPermanentWidget(0, graphics_api_button);
+
     statusBar()->addPermanentWidget(multiplayer_state->GetStatusText());
     statusBar()->addPermanentWidget(multiplayer_state->GetStatusIcon());
 
@@ -1988,6 +2004,7 @@ void GMainWindow::OnConfigure() {
         }
         UpdateSecondaryWindowVisibility();
         UpdateBootHomeMenuState();
+        UpdateAPIIndicator();
     } else {
         Settings::values.input_profiles = old_input_profiles;
         Settings::values.touch_from_button_maps = old_touch_from_button_maps;
@@ -2314,6 +2331,26 @@ void GMainWindow::ShowMouseCursor() {
     }
 }
 
+void GMainWindow::UpdateAPIIndicator(bool update) {
+    static std::array graphics_apis = {QStringLiteral("SOFTWARE"), QStringLiteral("OPENGL"),
+                                       QStringLiteral("VULKAN")};
+
+    static std::array graphics_api_colors = {QStringLiteral("#3ae400"), QStringLiteral("#00ccdd"),
+                                             QStringLiteral("#91242a")};
+
+    u32 api_index = static_cast<u32>(Settings::values.graphics_api.GetValue());
+    if (update) {
+        api_index = (api_index + 1) % graphics_apis.size();
+        Settings::values.graphics_api = static_cast<Settings::GraphicsAPI>(api_index);
+    }
+
+    const QString style_sheet = QStringLiteral("QPushButton { font-weight: bold; color: %0; }")
+                                    .arg(graphics_api_colors[api_index]);
+
+    graphics_api_button->setText(graphics_apis[api_index]);
+    graphics_api_button->setStyleSheet(style_sheet);
+}
+
 void GMainWindow::OnMouseActivity() {
     ShowMouseCursor();
 }

src/citra_qt/main.h

@@ -7,6 +7,7 @@
 #include <array>
 #include <memory>
 #include <QMainWindow>
+#include <QPushButton>
 #include <QTimer>
 #include <QTranslator>
 #include "citra_qt/compatibility_list.h"
@@ -254,6 +255,7 @@ private:
     void HideMouseCursor();
     void ShowMouseCursor();
     void OpenPerGameConfiguration(u64 title_id, const QString& file_name);
+    void UpdateAPIIndicator(bool update = false);
 
     std::unique_ptr<Ui::MainWindow> ui;
 
@@ -269,6 +271,7 @@ private:
     QLabel* emu_speed_label = nullptr;
     QLabel* game_fps_label = nullptr;
     QLabel* emu_frametime_label = nullptr;
+    QPushButton* graphics_api_button = nullptr;
     QTimer status_bar_update_timer;
     bool message_label_used_for_movie = false;