Qt: Fix saving settings enabling camera when camera name changes (fixes #2125)

CHANGES

@@ -17,6 +17,7 @@ Other fixes:
  - Qt: Fix crash when switching from high-resolution OpenGL renderer to software
  - Qt: Fix OpenGL renderer lagging behind when fast-forwarding (fixes mgba.io/i/2094)
  - Qt: Fix smudged window icon on Windows
+ - Qt: Fix saving settings enabling camera when camera name changes (fixes mgba.io/i/2125)
 Misc:
  - Core: Truncate preloading ROMs that slightly exceed max size (fixes mgba.io/i/2093)
  - GBA: Default-enable VBA bug compat for Ruby and Emerald ROM hacks

src/platform/qt/InputController.cpp

@@ -94,23 +94,23 @@ InputController::InputController(int playerId, QWidget* topLevel, QObject* paren
 		InputControllerImage* image = static_cast<InputControllerImage*>(context);
 		image->w = w;
 		image->h = h;
+		image->p->m_cameraActive = true;
 		if (image->image.isNull()) {
 			image->image.load(":/res/no-cam.png");
 		}
 #ifdef BUILD_QT_MULTIMEDIA
-		if (image->p->m_config->getQtOption("cameraDriver").toInt() == static_cast<int>(CameraDriver::QT_MULTIMEDIA)) {
 		QByteArray camera = image->p->m_config->getQtOption("camera").toByteArray();
 		if (!camera.isNull()) {
-				QMetaObject::invokeMethod(image->p, "setCamera", Q_ARG(QByteArray, camera));
+			image->p->m_cameraDevice = camera;
 		}
 		QMetaObject::invokeMethod(image->p, "setupCam");
-		}
 #endif
 	};
 
 	m_image.stopRequestImage = [](mImageSource* context) {
 		InputControllerImage* image = static_cast<InputControllerImage*>(context);
 #ifdef BUILD_QT_MULTIMEDIA
+		image->p->m_cameraActive = false;
 		QMetaObject::invokeMethod(image->p, "teardownCam");
 #endif
 	};
@@ -766,10 +766,18 @@ void InputController::setLuminanceValue(uint8_t value) {
 
 void InputController::setupCam() {
 #ifdef BUILD_QT_MULTIMEDIA
+	if (m_config->getQtOption("cameraDriver").toInt() != static_cast<int>(CameraDriver::QT_MULTIMEDIA)) {
+		return;
+	}
+
 	if (!m_camera) {
-		m_camera = std::make_unique<QCamera>();
+		m_camera = std::make_unique<QCamera>(m_cameraDevice);
 		connect(m_camera.get(), &QCamera::statusChanged, this, &InputController::prepareCamSettings, Qt::QueuedConnection);
 	}
+	if (m_camera->status() == QCamera::UnavailableStatus) {
+		m_camera.reset();
+		return;
+	}
 	m_camera->setCaptureMode(QCamera::CaptureVideo);
 	m_camera->setViewfinder(&m_videoDumper);
 	m_camera->load();
@@ -820,20 +828,22 @@ void InputController::prepareCamSettings(QCamera::Status status) {
 void InputController::teardownCam() {
 #ifdef BUILD_QT_MULTIMEDIA
 	if (m_camera) {
-		m_camera->stop();
+		m_camera->unload();
+		m_camera.reset();
 	}
 #endif
 }
 
 void InputController::setCamera(const QByteArray& name) {
 #ifdef BUILD_QT_MULTIMEDIA
-	bool needsRestart = false;
-	if (m_camera) {
-		needsRestart = m_camera->state() == QCamera::ActiveState;
+	if (m_cameraDevice == name) {
+		return;
 	}
-	m_camera = std::make_unique<QCamera>(name);
-	connect(m_camera.get(), &QCamera::statusChanged, this, &InputController::prepareCamSettings, Qt::QueuedConnection);
-	if (needsRestart) {
+	m_cameraDevice = name;
+	if (m_camera && m_camera->state() == QCamera::ActiveState) {
+		teardownCam();
+	}
+	if (m_cameraActive) {
 		setupCam();
 	}
 #endif

src/platform/qt/InputController.h

@@ -158,6 +158,8 @@ private:
 	} m_image;
 
 #ifdef BUILD_QT_MULTIMEDIA
+	bool m_cameraActive = false;
+	QByteArray m_cameraDevice;
 	std::unique_ptr<QCamera> m_camera;
 	VideoDumper m_videoDumper;
 #endif

src/platform/qt/SettingsView.cpp

@@ -503,10 +503,13 @@ void SettingsView::updateConfig() {
 	}
 
 	QVariant camera = m_ui.camera->itemData(m_ui.camera->currentIndex());
-	if (camera != m_controller->getQtOption("camera")) {
+	QVariant oldCamera = m_controller->getQtOption("camera");
+	if (camera != oldCamera) {
 		m_controller->setQtOption("camera", camera);
+		if (!oldCamera.isNull()) {
 			emit cameraChanged(camera.toByteArray());
 		}
+	}
 
 	QLocale language = m_ui.languages->itemData(m_ui.languages->currentIndex()).toLocale();
 	if (language != m_controller->getQtOption("language").toLocale() && !(language.bcp47Name() == QLocale::system().bcp47Name() && m_controller->getQtOption("language").isNull())) {