star trails

src/core/StelApp.cpp

@@ -977,10 +977,17 @@ void StelApp::highGraphicsModeDraw()
 
 	const QList<StelModule*> modules = moduleMgr->getCallOrders(StelModule::ActionDraw);
 
-	for(auto* module : modules)
-	{
-		module->draw(core);
-	}
+	if (core->getFlagClearSky())
+		for (auto* module : modules)
+		{
+			module->draw(core);
+		}
+	else
+		for (auto* module : modules)
+		{
+			if (! QStringList({"MilkyWay", "ZodiacalLight", "GridLinesMgr", "NebulaMgr"}).contains(module->objectName()))
+				module->draw(core);
+		}
 
 	if(sceneMultisampledFBO)
 	{
@@ -1051,10 +1058,17 @@ void StelApp::draw()
 	else
 	{
 		const QList<StelModule*> modules = moduleMgr->getCallOrders(StelModule::ActionDraw);
-		for (auto* module : modules)
-		{
-			module->draw(core);
-		}
+		if (core->getFlagClearSky())
+			for (auto* module : modules)
+			{
+				module->draw(core);
+			}
+		else
+			for (auto* module : modules)
+			{
+				if (! QStringList({"MilkyWay", "ZodiacalLight", "GridLinesMgr", "NebulaMgr"}).contains(module->objectName()))
+					module->draw(core);
+			}
 	}
 
 	core->postDraw();
@@ -1375,6 +1389,10 @@ void StelApp::setViewportEffect(const QString& name)
 	{
 		viewportEffect = new StelViewportDistorterFisheyeToSphericMirror(w, h);
 	}
+	else if (name == "viewportFaderEffect")
+	{
+		viewportEffect = new StelViewportFaderEffect();
+	}
 	else
 	{
 		qDebug() << "unknown viewport effect name:" << name;

src/core/StelCore.cpp

@@ -106,6 +106,7 @@
 	, de441Available(false)
 	, de440Active(false)
 	, de441Active(false)
+	, flagClearSky(true)
 {
 	setObjectName("StelCore");
 	registerMathMetaTypes();
@@ -355,6 +356,9 @@
 
 	actionsMgr->addAction("actionHorizontal_Flip", displayGroup, N_("Flip scene horizontally"), this, "flipHorz", "Ctrl+Shift+H", "", true);
 	actionsMgr->addAction("actionVertical_Flip", displayGroup, N_("Flip scene vertically"), this, "flipVert", "Ctrl+Shift+V", "", true);
+
+	actionsMgr->addAction("actionClear_Background", displayGroup, N_("Toggle background clearing"), this, "flagClearSky", "Ctrl+Alt+C", "", true);
+
 }
 
 QString StelCore::getDefaultProjectionTypeKey() const
@@ -530,7 +534,13 @@
 	Vec3f backColor = StelMainView::getInstance().getSkyBackgroundColor();
 	QOpenGLFunctions* gl = QOpenGLContext::currentContext()->functions();
 	gl->glClearColor(backColor[0], backColor[1], backColor[2], 0.f);
-	gl->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
+	if (flagClearSky)
+		gl->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
+	else
+	{
+		// TODO: dim whole framebuffer to 90%, else we are overexposed much too fast.
+		gl->glClear(GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
+	}
 
 	skyDrawer->preDraw();
 }
@@ -3044,3 +3054,10 @@
 	}
 	program.setUniformValue("STELCORE_currentPlanetHeliocentricEclipticVelocity", velocity.toQVector());
 }
+
+void StelCore::setFlagClearSky(const bool state)
+{
+	flagClearSky = state;
+	qDebug() << "flagClearSky now" << state;
+	emit flagClearSkyChanged(state);
+}

src/core/StelCore.hpp

@@ -67,6 +67,7 @@ class StelCore : public QObject
 	Q_PROPERTY(bool flagUseDST READ getUseDST WRITE setUseDST NOTIFY flagUseDSTChanged)
 	Q_PROPERTY(bool startupTimeStop READ getStartupTimeStop WRITE setStartupTimeStop NOTIFY startupTimeStopChanged)
 	Q_PROPERTY(DitheringMode ditheringMode READ getDitheringMode WRITE setDitheringMode NOTIFY ditheringModeChanged)
+	Q_PROPERTY(bool flagClearSky READ getFlagClearSky WRITE setFlagClearSky NOTIFY flagClearSkyChanged)
 
 public:
 	//! @enum FrameType
@@ -794,6 +795,11 @@ public slots:
 	//! Converts magnitude/arcsec² to luminance in cd/m².
 	static float mpsasToLuminance(const float mag) { return 10.8e4f*std::pow(10.f, -0.4f*mag); }
 
+	//! get state of the clear sky flag. For regular use it should be true, while false will overdraw the previous frame
+	bool getFlagClearSky() const {return flagClearSky;}
+	//! set state of the clear sky flag. For regular use it should be true, while false will overdraw the previous frame
+	void setFlagClearSky(const bool state);
+
 signals:
 	//! This signal is emitted when the observer location has changed.
 	void locationChanged(const StelLocation&);
@@ -847,6 +853,8 @@ public slots:
 	void configurationDataSaved();
 	void updateSearchLists();
 	void ditheringModeChanged(DitheringMode mode);
+	//! Emitted when clear sky flag changed.
+	void flagClearSkyChanged(bool state);
 
 private slots:
 	//! Call this whenever latitude changes. I.e., just connect it to the locationChanged() signal.
@@ -951,6 +959,8 @@ private slots:
 	bool de441Available; // ephem file found
 	bool de440Active;    // available and user-activated.
 	bool de441Active;    // available and user-activated.
+
+	bool flagClearSky; // Keep this true unless you want to render star streaks.
 };
 
 #endif // STELCORE_HPP

src/core/StelViewportEffect.cpp

@@ -148,7 +148,7 @@ StelViewportDistorterFisheyeToSphericMirror::StelViewportDistorterFisheyeToSpher
 
 				// sharp image up to the border of the fisheye image, at the cost of
 				// accepting clamping artefacts. You can get rid of the clamping
-				// artefacts by specifying a viewport size a little less then
+				// artefacts by specifying a viewport size a little less than
 				// (1<<n)*(1<<n), for instance 1022*1022. With a viewport size
 				// of 512*512 and viewportFovDiameter=512 you will get clamping
 				// artefacts in the 3 otherwise black hills on the bottom of the image.
@@ -177,7 +177,7 @@ StelViewportDistorterFisheyeToSphericMirror::StelViewportDistorterFisheyeToSpher
 		QTextStream in;
 		QString fName = StelFileMgr::findFile(custom_distortion_file);
 		if (fName.isEmpty()) {
-			qWarning() << "WARNING: could not open custom_distortion_file:" << custom_distortion_file;
+			qWarning() << "WARNING: could not find custom_distortion_file:" << custom_distortion_file;
 		} else {
 			file.setFileName(fName);
 			if(file.open(QIODevice::ReadOnly))
@@ -345,3 +345,13 @@ void StelViewportDistorterFisheyeToSphericMirror::paintViewportBuffer(const QOpe
 	GL(gl->glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST));
 }
 
+void StelViewportFaderEffect::paintViewportBuffer(const QOpenGLFramebufferObject* buf) const
+{
+	StelPainter sPainter(StelApp::getInstance().getCore()->getProjection2d());
+	QOpenGLFunctions* gl = sPainter.glFuncs();
+	sPainter.setColor(1,1,1);
+	GL(gl->glBindTexture(GL_TEXTURE_2D, buf->texture()));
+	GL(gl->glBlendColor(1, 1, 1, 0.08));
+	sPainter.setBlending(true, GL_CONSTANT_ALPHA, GL_ONE_MINUS_CONSTANT_ALPHA);
+	sPainter.drawRect2d(0, 0, buf->width(), buf->height());
+}

src/core/StelViewportEffect.hpp

@@ -70,5 +70,16 @@ class StelViewportDistorterFisheyeToSphericMirror : public StelViewportEffect
 	QVector<Vec2f> displayTexCoordList;
 };
 
+class StelViewportFaderEffect : public StelViewportEffect
+{
+public:
+	StelViewportFaderEffect() {}
+	virtual QString getName() const Q_DECL_OVERRIDE {return "viewportFaderEffect";}
+	//! Alter the GL frame buffer, this method must not display anything.
+	//! The implementation in this class reduces the brightness of the existing buffer.
+	// virtual void alterBuffer(QOpenGLFramebufferObject* buf) const Q_DECL_OVERRIDE;
+	virtual void paintViewportBuffer(const QOpenGLFramebufferObject* buf) const Q_DECL_OVERRIDE;
+};
+
 #endif // STELVIEWPORTEFFECT_HPP
 

src/core/modules/LandscapeMgr.cpp

@@ -664,7 +664,7 @@ void LandscapeMgr::draw(StelCore* core)
 	StelSkyDrawer* drawer=core->getSkyDrawer();
 
 	// Draw the atmosphere
-	if (!getFlagAtmosphereNoScatter())
+	if (!getFlagAtmosphereNoScatter() && core->getFlagClearSky())
 	    atmosphere->draw(core);
 
 	// GZ 2016-01: When we draw the atmosphere with a low sun, it is possible that the glaring red ball is overpainted and thus invisible.

src/core/modules/Planet.cpp

@@ -3082,11 +3082,12 @@ void Planet::draw(StelCore* core, float maxMagLabels, const QFont& planetNameFon
 		// by putting here, only draw orbit if Planet is visible for clarity
 		drawOrbit(core);  // TODO - fade in here also...
 
-		if (flagLabels && ang_dist>0.25f && maxMagLabels>getVMagnitudeWithExtinction(core))
+		if (flagLabels && ang_dist>0.25f && maxMagLabels>getVMagnitudeWithExtinction(core) && core->getFlagClearSky())
 			labelsFader=true;
 		else
 			labelsFader=false;
-		drawHints(core, planetNameFont);
+		if (core->getFlagClearSky())
+			drawHints(core, planetNameFont);
 
 		draw3dModel(core,transfo,static_cast<float>(screenRd));
 	}
@@ -3624,7 +3625,7 @@ void Planet::draw3dModel(StelCore* core, StelProjector::ModelViewTranformP trans
 	}
 
 	// Draw the halo if it enabled in the ssystem.ini file (+ special case for backward compatible for the Sun)
-	if (isSun && drawSunHalo && core->getSkyDrawer()->getFlagEarlySunHalo())
+	if (isSun && drawSunHalo && core->getSkyDrawer()->getFlagEarlySunHalo() && core->getFlagClearSky())
 	{
 		// Prepare openGL lighting parameters according to luminance
 		float surfArcMin2 = static_cast<float>(getSpheroidAngularRadius(core))*60.f;
@@ -3761,7 +3762,7 @@ void Planet::draw3dModel(StelCore* core, StelProjector::ModelViewTranformP trans
 		#endif
 	}
 
-	bool allowDrawHalo = !isSun || !core->getSkyDrawer()->getFlagEarlySunHalo(); // We had drawn the sun already before the sphere.
+	bool allowDrawHalo = core->getFlagClearSky() && ( !isSun || !core->getSkyDrawer()->getFlagEarlySunHalo()); // We had drawn the sun already before the sphere.
 	if (!isSun && !isMoon && currentLocationIsEarth)
 	{
 		// Let's hide halo when inner planet between Sun and observer (or moon between planet and observer).

src/core/modules/ZoneArray.cpp

@@ -490,7 +490,7 @@ void SpecialZoneArray<Star>::draw(StelPainter* sPainter, int index, bool isInsid
 			twinkleFactor=qMin(1.0f, 1.0f-0.9f*altAz[2]); // suppress twinkling in higher altitudes. Keep 0.1 twinkle amount in zenith.
 		}
 
-		if (drawer->drawPointSource(sPainter, vf.toVec3d(), *tmpRcmag, s->getBVIndex(), !isInsideViewport, twinkleFactor) && s->hasName() && extinctedMagIndex < maxMagStarName && s->hasComponentID()<=1)
+		if (drawer->drawPointSource(sPainter, vf.toVec3d(), *tmpRcmag, s->getBVIndex(), !isInsideViewport, twinkleFactor) && core->getFlagClearSky() && s->hasName() && extinctedMagIndex < maxMagStarName && s->hasComponentID()<=1)
 		{
 			const float offset = tmpRcmag->radius*0.7f;
 			const Vec3f colorr = StelSkyDrawer::indexToColor(s->getBVIndex())*0.75f;