Merge pull request #593 from Vort/atv_double_buffering

ATV Demodulator: implement double buffering

plugins/channelrx/demodatv/atvdemodsink.cpp

@@ -484,7 +484,7 @@ void ATVDemodSink::applyChannelSettings(int channelSampleRate, int channelFreque
             m_samplesPerLine - m_numberSamplesPerLineSignals,
             m_settings.m_nbLines - m_numberOfBlackLines
         );
-		m_tvScreenData = m_registeredTVScreen->getData();
+		m_tvScreenBuffer = m_registeredTVScreen->getBackBuffer();
     }
 
     m_fieldIndex = 0;
@@ -576,7 +576,7 @@ void ATVDemodSink::applySettings(const ATVDemodSettings& settings, bool force)
                 m_samplesPerLine - m_numberSamplesPerLineSignals,
                 m_settings.m_nbLines - m_numberOfBlackLines
             );
-			m_tvScreenData = m_registeredTVScreen->getData();
+			m_tvScreenBuffer = m_registeredTVScreen->getBackBuffer();
         }
 
         m_fieldIndex = 0;

plugins/channelrx/demodatv/atvdemodsink.h

@@ -109,7 +109,7 @@ private:
 
     //*************** ATV PARAMETERS  ***************
     TVScreenAnalog *m_registeredTVScreen;
-	std::shared_ptr<TVScreenAnalogData> m_tvScreenData;
+	std::shared_ptr<TVScreenAnalogBuffer> m_tvScreenBuffer;
 
     //int m_intNumberSamplePerLine;
     int m_numberSamplesPerHTopNom;     //!< number of samples per horizontal synchronization pulse (pulse in ultra-black) - nominal value
@@ -199,7 +199,7 @@ private:
     inline void processSample(float& sample, int& sampleVideo)
     {
         // Filling pixel on the current line - reference index 0 at start of sync pulse
-		m_tvScreenData->setSampleValue(m_sampleOffset - m_numberSamplesPerHSync, sampleVideo);
+		m_tvScreenBuffer->setSampleValue(m_sampleOffset - m_numberSamplesPerHSync, sampleVideo);
 
         if (m_settings.m_hSync)
         {
@@ -278,7 +278,7 @@ private:
     {
         if (m_lineIndex == m_numberOfVSyncLines + 3 && m_fieldIndex == 0)
         {
-			m_registeredTVScreen->renderImage();
+			m_tvScreenBuffer = m_registeredTVScreen->swapBuffers();
         }
 
         if (m_vSyncDetectSampleCount > m_vSyncDetectThreshold &&
@@ -311,7 +311,7 @@ private:
         if (m_interleaved)
             rowIndex = rowIndex * 2 - m_fieldIndex;
 
-		m_tvScreenData->selectRow(rowIndex, m_sampleOffsetFrac);
+		m_tvScreenBuffer->selectRow(rowIndex, m_sampleOffsetFrac);
 	}
 
     // Vertical sync is obtained by skipping horizontal sync on the line that triggers vertical sync (new frame)
@@ -320,11 +320,11 @@ private:
 		if ((m_sampleOffsetDetected > (3 * m_samplesPerLine) / 2) // Vertical sync is first horizontal sync after skip (count at least 1.5 line length)
             || (!m_settings.m_vSync && (m_lineIndex >= m_settings.m_nbLines))) // Vsync ignored and reached nominal number of lines per frame
         {
-			m_registeredTVScreen->renderImage();
+			m_tvScreenBuffer = m_registeredTVScreen->swapBuffers();
 			m_lineIndex = 0;
         }
 
-		m_tvScreenData->selectRow(m_lineIndex, m_sampleOffsetFrac);
+		m_tvScreenBuffer->selectRow(m_lineIndex, m_sampleOffsetFrac);
     }
 };
 

sdrgui/gui/tvscreenanalog.cpp

@@ -68,10 +68,11 @@ TVScreenAnalog::TVScreenAnalog(QWidget *parent)
 	: QGLWidget(parent)
 {
 	m_isDataChanged = false;
-	m_data = std::make_shared<TVScreenAnalogData>(5, 1);
+	m_frontBuffer = std::make_shared<TVScreenAnalogBuffer>(5, 1);
+	m_backBuffer = std::make_shared<TVScreenAnalogBuffer>(5, 1);
 
-	connect(&m_objTimer, SIGNAL(timeout()), this, SLOT(tick()));
+	connect(&m_updateTimer, SIGNAL(timeout()), this, SLOT(tick()));
-	m_objTimer.start(40); // capped at 25 FPS
+	m_updateTimer.start(40); // capped at 25 FPS
 }
 
 void TVScreenAnalog::cleanup()
@@ -81,9 +82,9 @@ void TVScreenAnalog::cleanup()
 	m_lineShiftsTexture = nullptr;
 }
 
-std::shared_ptr<TVScreenAnalogData> TVScreenAnalog::getData()
+std::shared_ptr<TVScreenAnalogBuffer> TVScreenAnalog::getBackBuffer()
 {
-	return m_data;
+	return m_backBuffer;
 }
 
 void TVScreenAnalog::resizeTVScreen(int intCols, int intRows)
@@ -91,8 +92,12 @@ void TVScreenAnalog::resizeTVScreen(int intCols, int intRows)
 	qDebug("TVScreen::resizeTVScreen: cols: %d, rows: %d", intCols, intRows);
 
 	int colsAdj = intCols + 4;
-	if (m_data->getWidth() != colsAdj || m_data->getHeight() != intRows)
+	QMutexLocker lock(&m_buffersMutex);
-		m_data = std::make_shared<TVScreenAnalogData>(colsAdj, intRows);
+	if (m_frontBuffer->getWidth() != colsAdj || m_frontBuffer->getHeight() != intRows)
+	{
+		m_frontBuffer = std::make_shared<TVScreenAnalogBuffer>(colsAdj, intRows);
+		m_backBuffer = std::make_shared<TVScreenAnalogBuffer>(colsAdj, intRows);
+	}
 }
 
 void TVScreenAnalog::resizeGL(int intWidth, int intHeight)
@@ -143,12 +148,12 @@ void TVScreenAnalog::initializeGL()
 	m_texelHeightLoc = m_shader->uniformLocation("tlh");
 }
 
-void TVScreenAnalog::initializeTextures()
+void TVScreenAnalog::initializeTextures(std::shared_ptr<TVScreenAnalogBuffer> buffer)
 {
 	m_imageTexture = std::make_shared<QOpenGLTexture>(QOpenGLTexture::Target2D);
 	m_lineShiftsTexture = std::make_shared<QOpenGLTexture>(QOpenGLTexture::Target2D);
-	m_imageTexture->setSize(m_data->getWidth(), m_data->getHeight());
+	m_imageTexture->setSize(buffer->getWidth(), buffer->getHeight());
-	m_lineShiftsTexture->setSize(1, m_data->getHeight());
+	m_lineShiftsTexture->setSize(1, buffer->getHeight());
 	m_imageTexture->setFormat(QOpenGLTexture::RGBA8_UNorm);
 	m_lineShiftsTexture->setFormat(QOpenGLTexture::RGBA8_UNorm);
 	m_imageTexture->setAutoMipMapGenerationEnabled(false);
@@ -166,9 +171,12 @@ void TVScreenAnalog::initializeTextures()
 	m_lineShiftsTexture->setWrapMode(QOpenGLTexture::DirectionT, QOpenGLTexture::ClampToEdge);
 }
 
-void TVScreenAnalog::renderImage()
+std::shared_ptr<TVScreenAnalogBuffer> TVScreenAnalog::swapBuffers()
 {
+	QMutexLocker lock(&m_buffersMutex);
+	std::swap(m_frontBuffer, m_backBuffer);
 	m_isDataChanged = true;
+	return m_backBuffer;
 }
 
 void TVScreenAnalog::tick()
@@ -190,15 +198,17 @@ void TVScreenAnalog::paintGL()
 		return;
 	}
 
+	std::shared_ptr<TVScreenAnalogBuffer> buffer = m_frontBuffer;
+
 	if (!m_imageTexture ||
-		m_imageTexture->width() != m_data->getWidth() ||
+		m_imageTexture->width() != buffer->getWidth() ||
-		m_imageTexture->height() != m_data->getHeight())
+		m_imageTexture->height() != buffer->getHeight())
 	{
-		initializeTextures();
+		initializeTextures(buffer);
 	}
 
-	float imageWidth = m_data->getWidth();
+	float imageWidth = buffer->getWidth();
-	float imageHeight = m_data->getHeight();
+	float imageHeight = buffer->getHeight();
 	float texelWidth = 1.0f / imageWidth;
 	float texelHeight = 1.0f / imageHeight;
 
@@ -213,12 +223,12 @@ void TVScreenAnalog::paintGL()
 	glActiveTexture(GL_TEXTURE0);
 	m_imageTexture->bind();
 	glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0,
-		m_data->getWidth(), m_data->getHeight(), GL_RGBA, GL_UNSIGNED_BYTE, m_data->getImageData());
+		buffer->getWidth(), buffer->getHeight(), GL_RGBA, GL_UNSIGNED_BYTE, buffer->getImageData());
 
 	glActiveTexture(GL_TEXTURE1);
 	m_lineShiftsTexture->bind();
 	glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0,
-		1, m_data->getHeight(), GL_RGBA, GL_UNSIGNED_BYTE, m_data->getLineShiftData());
+		1, buffer->getHeight(), GL_RGBA, GL_UNSIGNED_BYTE, buffer->getLineShiftData());
 
 	float rectHalfWidth = 1.0f + 4.0f / (imageWidth - 4.0f);
 	GLfloat vertices[] =

sdrgui/gui/tvscreenanalog.h

@@ -28,7 +28,6 @@
 #include <memory>
 #include <algorithm>
 
-#include <QImage>
 #include <QMutex>
 #include <QTimer>
 #include <QGLWidget>
@@ -36,10 +35,10 @@
 #include <QOpenGLFunctions>
 #include <QOpenGLShaderProgram>
 
-class TVScreenAnalogData
+class TVScreenAnalogBuffer
 {
 public:
-	TVScreenAnalogData(int width, int height)
+	TVScreenAnalogBuffer(int width, int height)
 	{
 		m_width = width;
 		m_height = height;
@@ -53,7 +52,7 @@ public:
 		std::fill(m_lineShiftData, m_lineShiftData + height, 127);
 	}
 
-	~TVScreenAnalogData()
+	~TVScreenAnalogBuffer()
 	{
 		delete[] m_imageData;
 		delete[] m_lineShiftData;
@@ -116,7 +115,7 @@ class SDRGUI_API TVScreenAnalog : public QGLWidget, protected QOpenGLFunctions
 {
 	Q_OBJECT
 
-	QTimer m_objTimer;
+	QTimer m_updateTimer;
 
 	bool m_isDataChanged;
 
@@ -129,7 +128,9 @@ class SDRGUI_API TVScreenAnalog : public QGLWidget, protected QOpenGLFunctions
 	int m_vertexAttribIndex;
 	int m_texCoordAttribIndex;
 
-	std::shared_ptr<TVScreenAnalogData> m_data;
+	QMutex m_buffersMutex;
+	std::shared_ptr<TVScreenAnalogBuffer> m_frontBuffer;
+	std::shared_ptr<TVScreenAnalogBuffer> m_backBuffer;
 
 	std::shared_ptr<QOpenGLShaderProgram> m_shader;
 	std::shared_ptr<QOpenGLTexture> m_imageTexture;
@@ -138,12 +139,12 @@ class SDRGUI_API TVScreenAnalog : public QGLWidget, protected QOpenGLFunctions
 public:
 	TVScreenAnalog(QWidget *parent);
 
-	std::shared_ptr<TVScreenAnalogData> getData();
+	std::shared_ptr<TVScreenAnalogBuffer> getBackBuffer();
+	std::shared_ptr<TVScreenAnalogBuffer> swapBuffers();
 	void resizeTVScreen(int intCols, int intRows);
-	void renderImage();
 
 private:
-	void initializeTextures();
+	void initializeTextures(std::shared_ptr<TVScreenAnalogBuffer> buffer);
 	void initializeGL() override;
 	void paintGL() override;
 	void resizeGL(int width, int height);