hyperion.ng/libsrc/grabber/dispmanx/DispmanxFrameGrabber.cpp

// STL includes
#include <cassert>
#include <iostream>

//Qt
#include <QJsonObject>
#include <QJsonArray>
#include <QJsonDocument>
#include <QSize>

// Constants
namespace {
const bool verbose = false;
const int DEFAULT_DEVICE = 0;

} //End of constants

// Local includes
#include "grabber/DispmanxFrameGrabber.h"

DispmanxFrameGrabber::DispmanxFrameGrabber()
	: Grabber("DISPMANXGRABBER")
	  , _vc_display(0)
	  , _vc_resource(0)
	  , _vc_flags(DISPMANX_TRANSFORM_T(0))
	  , _captureBuffer(new ColorRgba[0])
	  , _captureBufferSize(0)
	  , _image_rgba()
{
	_useImageResampler = true;
	// Initialise BCM
	bcm_host_init();
}

DispmanxFrameGrabber::~DispmanxFrameGrabber()
{
	freeResources();

	// De-init BCM
	bcm_host_deinit();
}

bool DispmanxFrameGrabber::setupScreen()
{
	bool rc (false);

	int deviceIdx (DEFAULT_DEVICE);

	QSize screenSize = getScreenSize(deviceIdx);
	if ( screenSize.isEmpty() )
	{
		Error(_log, "Failed to open display [%d]! Probably no permissions to access the capture interface", deviceIdx);
		setEnabled(false);
	}
	else
	{
		setWidthHeight(screenSize.width(), screenSize.height());
		Info(_log, "Display [%d] opened with resolution: %dx%d", deviceIdx, screenSize.width(), screenSize.height());
		setEnabled(true);
		rc = true;
	}
	return rc;
}

void DispmanxFrameGrabber::freeResources()
{
	delete[] _captureBuffer;
	// Clean up resources
	vc_dispmanx_resource_delete(_vc_resource);
}

bool DispmanxFrameGrabber::setWidthHeight(int width, int height)
{
	bool rc = false;
	if(Grabber::setWidthHeight(width, height))
	{
		if(_vc_resource != 0) {
			vc_dispmanx_resource_delete(_vc_resource);
		}

		Debug(_log,"Create the resources for capturing image");
		uint32_t vc_nativeImageHandle;
		_vc_resource = vc_dispmanx_resource_create(
			VC_IMAGE_RGBA32,
			width,
			height,
			&vc_nativeImageHandle);
		assert(_vc_resource);

		if (_vc_resource != 0)
		{
			Debug(_log,"Define the capture rectangle with the same size");
			vc_dispmanx_rect_set(&_rectangle, 0, 0, width, height);
			rc = true;
		}
	}
	return rc;
}

void DispmanxFrameGrabber::setFlags(DISPMANX_TRANSFORM_T vc_flags)
{
	_vc_flags = vc_flags;
}

int DispmanxFrameGrabber::grabFrame(Image<ColorRgb> & image)
{
	int rc = 0;
	if (_isEnabled && !_isDeviceInError)
	{
		// vc_dispmanx_resource_read_data doesn't seem to work well
		// with arbitrary positions so we have to handle cropping by ourselves
		int cropLeft   = _cropLeft;
		int cropRight  = _cropRight;
		int cropTop    = _cropTop;
		int cropBottom = _cropBottom;

		if (_vc_flags & DISPMANX_SNAPSHOT_FILL)
		{
			// disable cropping, we are capturing the video overlay window
			Debug(_log,"Disable cropping, as the video overlay window is captured");
			cropLeft = cropRight = cropTop = cropBottom = 0;
		}

		unsigned imageWidth  = static_cast<unsigned>(_width - cropLeft - cropRight);
		unsigned imageHeight = static_cast<unsigned>(_height - cropTop - cropBottom);

		// resize the given image if needed
		if (image.width() != imageWidth || image.height() != imageHeight)
		{
			image.resize(imageWidth, imageHeight);
		}

		if (_image_rgba.width() != imageWidth || _image_rgba.height() != imageHeight)
		{
			_image_rgba.resize(imageWidth, imageHeight);
		}

		// Open the connection to the display
		_vc_display = vc_dispmanx_display_open(DEFAULT_DEVICE);
		if (_vc_display < 0)
		{
			Error(_log, "Cannot open display: %d", DEFAULT_DEVICE);
			rc = -1;
		}
		else {

			// Create the snapshot (incl down-scaling)
			int ret = vc_dispmanx_snapshot(_vc_display, _vc_resource, _vc_flags);
			if (ret < 0)
			{
				Error(_log, "Snapshot failed: %d", ret);
				rc = ret;
			}
			else
			{
				// Read the snapshot into the memory
				void* imagePtr   = _image_rgba.memptr();
				void* capturePtr = imagePtr;

				unsigned imagePitch = imageWidth * sizeof(ColorRgba);

				// dispmanx seems to require the pitch to be a multiple of 64
				unsigned capturePitch = (_rectangle.width * sizeof(ColorRgba) + 63) & (~63);

				// grab to temp buffer if image pitch isn't valid or if we are cropping
				if (imagePitch != capturePitch
					 || static_cast<unsigned>(_rectangle.width) != imageWidth
					 || static_cast<unsigned>(_rectangle.height) != imageHeight)
				{
					// check if we need to resize the capture buffer
					unsigned captureSize = capturePitch * static_cast<unsigned>(_rectangle.height) / sizeof(ColorRgba);
					if (_captureBufferSize != captureSize)
					{
						delete[] _captureBuffer;
						_captureBuffer = new ColorRgba[captureSize];
						_captureBufferSize = captureSize;
					}

					capturePtr = &_captureBuffer[0];
				}

				ret = vc_dispmanx_resource_read_data(_vc_resource, &_rectangle, capturePtr, capturePitch);
				if (ret < 0)
				{
					Error(_log, "vc_dispmanx_resource_read_data failed: %d", ret);
					rc = ret;
				}
				else
				{
					_imageResampler.processImage(static_cast<uint8_t*>(capturePtr),
												  _width,
												  _height,
												  static_cast<int>(capturePitch),
												  PixelFormat::RGB32,
												  image);
				}
			}
			vc_dispmanx_display_close(_vc_display);
		}
	}
	return rc;
}

QSize DispmanxFrameGrabber::getScreenSize(int device) const
{
	int width (0);
	int height(0);

	DISPMANX_DISPLAY_HANDLE_T vc_display = vc_dispmanx_display_open(device);
	if ( vc_display > 0)
	{
		// Obtain the display information
		DISPMANX_MODEINFO_T vc_info;
		int result = vc_dispmanx_display_get_info(vc_display, &vc_info);
		(void)result;

		if (result == 0)
		{
			width = vc_info.width;
			height = vc_info.height;

			DebugIf(verbose, _log, "Display found with resolution: %dx%d", width, height);
		}
		// Close the display
		vc_dispmanx_display_close(vc_display);
	}

	return QSize(width, height);
}

QJsonObject DispmanxFrameGrabber::discover(const QJsonObject& params)
{
	DebugIf(verbose, _log, "params: [%s]", QString(QJsonDocument(params).toJson(QJsonDocument::Compact)).toUtf8().constData());

	QJsonObject inputsDiscovered;

	int deviceIdx (DEFAULT_DEVICE);
	QJsonArray video_inputs;

	QSize screenSize = getScreenSize(deviceIdx);
	if ( !screenSize.isEmpty() )
	{
		QJsonArray fps = { 1, 5, 10, 15, 20, 25, 30, 40, 50, 60 };

		QJsonObject in;

		QString displayName;
		displayName = QString("Screen:%1").arg(deviceIdx);

		in["name"] = displayName;
		in["inputIdx"] = deviceIdx;

		QJsonArray formats;
		QJsonObject format;

		QJsonArray resolutionArray;

		QJsonObject resolution;

		resolution["width"] = screenSize.width();
		resolution["height"] = screenSize.height();
		resolution["fps"] = fps;

		resolutionArray.append(resolution);

		format["resolutions"] = resolutionArray;
		formats.append(format);

		in["formats"] = formats;
		video_inputs.append(in);
	}

	if (!video_inputs.isEmpty())
	{
		inputsDiscovered["device"] = "dispmanx";
		inputsDiscovered["device_name"] = "DispmanX";
		inputsDiscovered["type"] = "screen";
		inputsDiscovered["video_inputs"] = video_inputs;
	}

	if (inputsDiscovered.isEmpty())
	{
		DebugIf(verbose, _log, "No displays found to capture from!");
	}

	DebugIf(verbose, _log, "device: [%s]", QString(QJsonDocument(inputsDiscovered).toJson(QJsonDocument::Compact)).toUtf8().constData());

	return inputsDiscovered;
}