libcamera: Switch to FrameBuffer interface

Switch to the FrameBuffer interface where all buffers are treated as
external buffers and are allocated outside the camera. Applications
allocating buffers using libcamera are switched to use the
FrameBufferAllocator helper.

Follow-up changes to this one will finalize the transition to the new
FrameBuffer interface by removing code that is left unused after this
change.

Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/qcam/main_window.cpp

@@ -23,7 +23,7 @@
 using namespace libcamera;
 
 MainWindow::MainWindow(CameraManager *cm, const OptionsParser::Options &options)
-	: options_(options), isCapturing_(false)
+	: options_(options), allocator_(nullptr), isCapturing_(false)
 {
 	int ret;
 
@@ -37,8 +37,10 @@ MainWindow::MainWindow(CameraManager *cm, const OptionsParser::Options &options)
 	adjustSize();
 
 	ret = openCamera(cm);
-	if (!ret)
+	if (!ret) {
+		allocator_ = FrameBufferAllocator::create(camera_);
 		ret = startCapture();
+	}
 
 	if (ret < 0)
 		QTimer::singleShot(0, QCoreApplication::instance(),
@@ -49,6 +51,7 @@ MainWindow::~MainWindow()
 {
 	if (camera_) {
 		stopCapture();
+		delete allocator_;
 		camera_->release();
 		camera_.reset();
 	}
@@ -176,8 +179,14 @@ int MainWindow::startCapture()
 		return ret;
 	}
 
+	ret = allocator_->allocate(stream);
+	if (ret < 0) {
+		std::cerr << "Failed to allocate capture buffers" << std::endl;
+		return ret;
+	}
+
 	std::vector<Request *> requests;
-	for (unsigned int i = 0; i < cfg.bufferCount; ++i) {
+	for (const std::unique_ptr<FrameBuffer> &buffer : allocator_->buffers(stream)) {
 		Request *request = camera_->createRequest();
 		if (!request) {
 			std::cerr << "Can't create request" << std::endl;
@@ -185,13 +194,7 @@ int MainWindow::startCapture()
 			goto error;
 		}
 
-		std::unique_ptr<Buffer> buffer = stream->createBuffer(i);
-		if (!buffer) {
-			std::cerr << "Can't create buffer " << i << std::endl;
-			goto error;
-		}
-
-		ret = request->addBuffer(stream, std::move(buffer));
+		ret = request->addBuffer(stream, buffer.get());
 		if (ret < 0) {
 			std::cerr << "Can't set buffer for request" << std::endl;
 			goto error;
@@ -254,11 +257,11 @@ void MainWindow::requestComplete(Request *request)
 	if (request->status() == Request::RequestCancelled)
 		return;
 
-	const std::map<Stream *, Buffer *> &buffers = request->buffers();
+	const std::map<Stream *, FrameBuffer *> &buffers = request->buffers();
 
 	framesCaptured_++;
 
-	Buffer *buffer = buffers.begin()->second;
+	FrameBuffer *buffer = buffers.begin()->second;
 	const FrameMetadata &metadata = buffer->metadata();
 
 	double fps = metadata.timestamp - lastBufferTime_;
@@ -281,28 +284,21 @@ void MainWindow::requestComplete(Request *request)
 
 	for (auto it = buffers.begin(); it != buffers.end(); ++it) {
 		Stream *stream = it->first;
-		Buffer *buffer = it->second;
-		unsigned int index = buffer->index();
+		FrameBuffer *buffer = it->second;
 
-		std::unique_ptr<Buffer> newBuffer = stream->createBuffer(index);
-		if (!newBuffer) {
-			std::cerr << "Can't create buffer" << std::endl;
-			return;
-		}
-
-		request->addBuffer(stream, std::move(newBuffer));
+		request->addBuffer(stream, buffer);
 	}
 
 	camera_->queueRequest(request);
 }
 
-int MainWindow::display(Buffer *buffer)
+int MainWindow::display(FrameBuffer *buffer)
 {
-	if (buffer->mem()->planes().size() != 1)
+	if (buffer->planes().size() != 1)
 		return -EINVAL;
 
 	/* \todo Once the FrameBuffer is done cache mapped memory. */
-	const FrameBuffer::Plane &plane = buffer->mem()->planes().front();
+	const FrameBuffer::Plane &plane = buffer->planes().front();
 	void *memory = mmap(NULL, plane.length, PROT_READ, MAP_SHARED,
 			    plane.fd.fd(), 0);