Qt: Improve camera initialization

CHANGES

@@ -24,6 +24,7 @@ Misc:
  - Debugger: Add breakpoint and watchpoint listing
  - Qt: Add missing HEVC NVENC option (fixes mgba.io/i/1323)
  - LR35902: Support PC-relative opcode decoding
+ - Qt: Improve camera initialization
 
 0.7.1: (2019-02-24)
 Bugfixes:

src/platform/qt/InputController.cpp

@@ -725,12 +725,23 @@ void InputController::setupCam() {
 #ifdef BUILD_QT_MULTIMEDIA
 	if (!m_camera) {
 		m_camera = std::make_unique<QCamera>();
+		connect(m_camera.get(), &QCamera::statusChanged, this, &InputController::prepareCamSettings);
 	}
-	QVideoFrame::PixelFormat format(QVideoFrame::Format_RGB32);
+	m_camera->setCaptureMode(QCamera::CaptureVideo);
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 5, 0))
+	m_camera->setViewfinder(&m_videoDumper);
 	m_camera->load();
+#endif
+}
+
+#ifdef BUILD_QT_MULTIMEDIA
+void InputController::prepareCamSettings(QCamera::Status status) {
+	if (status != QCamera::LoadedStatus || m_camera->state() == QCamera::ActiveState) {
+		return;
+	}
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 5, 0))
+	QVideoFrame::PixelFormat format(QVideoFrame::Format_RGB32);
 	QCameraViewfinderSettings settings;
-	QSize size(1920, 1080);
+	QSize size(1280, 720);
 	auto cameraRes = m_camera->supportedViewfinderResolutions(settings);
 	for (auto& cameraSize : cameraRes) {
 		if (cameraSize.width() < m_image.w || cameraSize.height() < m_image.h) {
@@ -741,10 +752,11 @@ void InputController::setupCam() {
 		}
 	}
 	settings.setResolution(size);
+
 	auto cameraFormats = m_camera->supportedViewfinderPixelFormats(settings);
 	auto goodFormats = m_videoDumper.supportedPixelFormats();
 	bool goodFormatFound = false;
-	for (auto& goodFormat : goodFormats) {
+	for (const auto& goodFormat : goodFormats) {
 		if (cameraFormats.contains(goodFormat)) {
 			settings.setPixelFormat(goodFormat);
 			format = goodFormat;
@@ -754,20 +766,20 @@ void InputController::setupCam() {
 	}
 	if (!goodFormatFound) {
 		LOG(QT, WARN) << "Could not find a valid camera format!";
+		for (const auto& format : cameraFormats) {
+			LOG(QT, WARN) << "Camera supported format: " << QString::number(format);
+		}
 	}
 	m_camera->setViewfinderSettings(settings);
 #endif
-	m_camera->setCaptureMode(QCamera::CaptureVideo);
-	m_camera->setViewfinder(&m_videoDumper);
 	m_camera->start();
-#endif
 }
+#endif
 
 void InputController::teardownCam() {
 #ifdef BUILD_QT_MULTIMEDIA
 	if (m_camera) {
 		m_camera->stop();
-		m_camera.reset();
 	}
 #endif
 }

src/platform/qt/InputController.h

@@ -27,13 +27,12 @@
 
 #ifdef BUILD_QT_MULTIMEDIA
 #include "VideoDumper.h"
+#include <QCamera>
 #endif
 
 struct mRotationSource;
 struct mRumble;
 
-class QCamera;
-
 namespace QGBA {
 
 class ConfigController;
@@ -124,6 +123,9 @@ public slots:
 	void setCamImage(const QImage& image);
 
 private slots:
+#ifdef BUILD_QT_MULTIMEDIA
+	void prepareCamSettings(QCamera::Status);
+#endif
 	void setupCam();
 	void teardownCam();
 

src/platform/qt/VideoDumper.cpp

@@ -23,14 +23,18 @@ bool VideoDumper::present(const QVideoFrame& frame) {
 	QImage::Format format = QVideoFrame::imageFormatFromPixelFormat(vFormat);
 	bool swap = false;
 	if (format == QImage::Format_Invalid) {
-		vFormat = static_cast<QVideoFrame::PixelFormat>(vFormat - QVideoFrame::Format_BGRA32 + QVideoFrame::Format_ARGB32);
+		if (vFormat < QVideoFrame::Format_BGRA5658_Premultiplied) {
-		format = QVideoFrame::imageFormatFromPixelFormat(vFormat);
+			vFormat = static_cast<QVideoFrame::PixelFormat>(vFormat - QVideoFrame::Format_BGRA32 + QVideoFrame::Format_ARGB32);
-		if (format == QImage::Format_ARGB32) {
+			format = QVideoFrame::imageFormatFromPixelFormat(vFormat);
-			format = QImage::Format_RGBA8888;
+			if (format == QImage::Format_ARGB32) {
-		} else if (format == QImage::Format_ARGB32_Premultiplied) {
+				format = QImage::Format_RGBA8888;
-			format = QImage::Format_RGBA8888_Premultiplied;
+			} else if (format == QImage::Format_ARGB32_Premultiplied) {
+				format = QImage::Format_RGBA8888_Premultiplied;
+			}
+			swap = true;
+		} else {
+			return false;
 		}
-		swap = true;
 	}
 	uchar* bits = mappedFrame.bits();
 	QImage image(bits, mappedFrame.width(), mappedFrame.height(), mappedFrame.bytesPerLine(), format);