Projection: plate carree (#2856)

* Cleanup
- implementation of 3 methods in base class
- Removed corresponding overrides in several derived classes
- Follow Qt's recommendation to code style (Q_DECL_OVERRIDE -> override)

* Added new projection: ProjectionCylinderFill (derived from ProjectionCylinder)
- Called Equirectangular to the users, a projection with automated windows stretching
- Inhibit zooming and panning for the new projection.

src/core/StelCore.cpp

@@ -407,6 +407,9 @@ StelProjectorP StelCore::getProjection(StelProjector::ModelViewTranformP modelVi
 		case ProjectionCylinder:
 			prj = StelProjectorP(new StelProjectorCylinder(modelViewTransform));
 			break;
+		case ProjectionCylinderFill:
+			prj = StelProjectorP(new StelProjectorCylinderFill(modelViewTransform));
+			break;
 		case ProjectionMercator:
 			prj = StelProjectorP(new StelProjectorMercator(modelViewTransform));
 			break;
@@ -479,6 +482,12 @@ void StelCore::windowHasBeenResized(qreal x, qreal y, qreal width, qreal height)
 	currentProjectorParams.viewportXywh.set(qRound(x), qRound(y), qRound(width), qRound(height));
 	currentProjectorParams.viewportCenter.set(x+(0.5+currentProjectorParams.viewportCenterOffset.v[0])*width, y+(0.5+currentProjectorParams.viewportCenterOffset.v[1])*height);
 	currentProjectorParams.viewportFovDiameter = qMin(width,height);
+
+	if (currentProjectionType==ProjectionType::ProjectionCylinderFill)
+	{
+		currentProjectorParams.widthStretch=0.5*width/height;
+		currentProjectorParams.viewportFovDiameter = height;
+	}
 }
 
 /*************************************************************************
@@ -544,8 +553,27 @@ void StelCore::setCurrentProjectionType(ProjectionType type)
 {
 	if(type!=currentProjectionType)
 	{
+		QSettings* conf = StelApp::getInstance().getSettings();
+
 		currentProjectionType=type;
 		updateMaximumFov();
+		if (currentProjectionType==ProjectionType::ProjectionCylinderFill)
+		{
+			// Save whatever stretch is present into config.ini. This value is saved just temporarily until switching back to another projection and will not be loaded on startup.
+			// (To configure a stretch at startup, use startup.ssc script.)
+			conf->setValue("projection/width_stretch", currentProjectorParams.widthStretch);
+			currentProjectorParams.fov=180.f;
+			currentProjectorParams.widthStretch=0.5*currentProjectorParams.viewportXywh[2]/currentProjectorParams.viewportXywh[3];
+			currentProjectorParams.viewportFovDiameter = currentProjectorParams.viewportXywh[3];
+			Q_ASSERT(movementMgr);
+			movementMgr->setViewportVerticalOffsetTarget(0.);
+			movementMgr->zoomTo(180., 0.5);
+		}
+		else
+		{
+			// reset to what is stored in config.ini
+			currentProjectorParams.widthStretch=conf->value("projection/width_stretch", 1.0).toDouble();
+		}
 
 		emit currentProjectionTypeChanged(type);
 		emit currentProjectionTypeKeyChanged(getCurrentProjectionTypeKey());

src/core/StelCore.hpp

@@ -101,6 +101,7 @@ class StelCore : public QObject
 		ProjectionMercator,		//!< Mercator projection
 		ProjectionMiller,		//!< Miller cylindrical projection
 		ProjectionCylinder,		//!< Cylinder projection
+		ProjectionCylinderFill		//!< Cylinder projection, no zoom or movement allowed
 	};
 	Q_ENUM(ProjectionType)
 

src/core/StelMovementMgr.cpp

@@ -1542,6 +1542,24 @@ void StelMovementMgr::setViewDirectionJ2000(const Vec3d& v)
 
 void StelMovementMgr::panView(const double deltaAz, const double deltaAlt)
 {
+	if (core->getCurrentProjectionType()==StelCore::ProjectionCylinderFill) // Inhibit any motion in this projection!
+	{
+		Vec3d tmp;
+		switch (mountMode){
+			case MountEquinoxEquatorial:
+				StelUtils::spheToRect(M_PI, 0., tmp);
+				break;
+			default:
+				StelUtils::spheToRect(0., 0., tmp);
+				break;
+		}
+
+		setViewDirectionJ2000(mountFrameToJ2000(tmp));
+		setViewUpVector(Vec3d(0., 0., 1.));
+
+		return;
+	}
+
 	// DONE 2016-12 FIX UP VECTOR PROBLEM
 	// The function is called in update loops, so make a quick check for exit.
 	if ((deltaAz==0.) && (deltaAlt==0.))

src/core/StelMovementMgr.hpp

@@ -24,6 +24,7 @@
 #include "StelModule.hpp"
 #include "StelObjectType.hpp"
 #include "VecMath.hpp"
+#include "StelCore.hpp"
 #include <QTimeLine>
 #include <QTimer>
 #include <QCursor>
@@ -479,9 +480,15 @@ private slots:
 	double maxFov;     // Maximum FOV in degrees. Depends on projection.
 	double userMaxFov; // Custom setting. Can be useful in a planetarium context.
 	double deltaFov;   // requested change of FOV (degrees) used during zooming.
+	StelCore* core;          // The core on which the movement are applied
+	QSettings* conf;
+	class StelObjectMgr* objectMgr;
 	void setFov(double f)
 	{
-		currentFov=qBound(minFov, f, maxFov);
+		if (core->getCurrentProjectionType()==StelCore::ProjectionCylinderFill)
+			currentFov=180.0;
+		else
+			currentFov=qBound(minFov, f, maxFov);
 	}
 	// immediately add deltaFov argument to FOV - does not change private var.
 	void changeFov(double deltaFov);
@@ -494,9 +501,6 @@ private slots:
 	//! Make the first screen position correspond to the second (useful for mouse dragging and also time dragging.)
 	void dragView(int x1, int y1, int x2, int y2);
 
-	StelCore* core;          // The core on which the movement are applied
-	QSettings* conf;
-	class StelObjectMgr* objectMgr;
 	bool flagLockEquPos;     // Define if the equatorial position is locked
 	bool flagTracking;       // Define if the selected object is followed
 	bool flagInhibitAllAutomoves; // Required for special installations: If true, there is no automatic centering etc.

src/core/StelProjector.cpp

@@ -164,7 +164,7 @@ void StelProjector::init(const StelProjectorParams& params)
 	flipHorz = params.flipHorz ? -1.f : 1.f;
 	flipVert = params.flipVert ? -1.f : 1.f;
 	viewportFovDiameter = params.viewportFovDiameter * devicePixelsPerPixel;
-	pixelPerRad = 0.5f * static_cast<float>(viewportFovDiameter) / fovToViewScalingFactor(params.fov*(static_cast<float>(M_PI)/360.f));
+	pixelPerRad = 0.5f * static_cast<float>(viewportFovDiameter) / fovToViewScalingFactor(params.fov*(static_cast<float>(M_PI/360.)));
 	widthStretch = params.widthStretch;
 	computeBoundingCap();
 }

src/core/StelProjector.hpp

@@ -72,18 +72,18 @@ class StelProjector
 	class Mat4dTransform: public ModelViewTranform
 	{
 	public:
-        Mat4dTransform(const Mat4d& altAzToWorld, const Mat4d& vertexToAltAzPos);
-	void forward(Vec3d& v) const Q_DECL_OVERRIDE;
-	void backward(Vec3d& v) const Q_DECL_OVERRIDE;
-	void forward(Vec3f& v) const Q_DECL_OVERRIDE;
-	void backward(Vec3f& v) const Q_DECL_OVERRIDE;
-	void combine(const Mat4d& m) Q_DECL_OVERRIDE;
-	Mat4d getApproximateLinearTransfo() const Q_DECL_OVERRIDE;
-	ModelViewTranformP clone() const Q_DECL_OVERRIDE;
-	QByteArray getForwardTransformShader() const Q_DECL_OVERRIDE;
-	void setForwardTransformUniforms(QOpenGLShaderProgram& program) const Q_DECL_OVERRIDE;
-	QByteArray getBackwardTransformShader() const Q_DECL_OVERRIDE;
-	void setBackwardTransformUniforms(QOpenGLShaderProgram& program) const Q_DECL_OVERRIDE;
+		Mat4dTransform(const Mat4d& altAzToWorld, const Mat4d& vertexToAltAzPos);
+		void forward(Vec3d& v) const override;
+		void backward(Vec3d& v) const override;
+		void forward(Vec3f& v) const override;
+		void backward(Vec3f& v) const override;
+		void combine(const Mat4d& m) override;
+		Mat4d getApproximateLinearTransfo() const override;
+		ModelViewTranformP clone() const override;
+		QByteArray getForwardTransformShader() const override;
+		void setForwardTransformUniforms(QOpenGLShaderProgram& program) const override;
+		QByteArray getBackwardTransformShader() const override;
+		void setBackwardTransformUniforms(QOpenGLShaderProgram& program) const override;
 
 	private:
 		Mat4dTransform(const Mat4dTransform& src) = default;
@@ -126,7 +126,7 @@ class StelProjector
 			, devicePixelsPerPixel(1)
 			, widthStretch(1) {}
 
-		Vector4<int> viewportXywh;       //! posX, posY, width, height
+		Vec4i viewportXywh;              //! posX, posY, width, height
 		float fov;                       //! FOV in degrees
 		bool gravityLabels;              //! the flag to use gravity labels or not
 		float defaultAngleForGravityText;//! a rotation angle to apply to gravity text (only if gravityLabels is set to false)
@@ -145,7 +145,7 @@ class StelProjector
 	virtual ~StelProjector() {}
 
 	///////////////////////////////////////////////////////////////////////////
-	// Methods which must be reimplemented by all instance of StelProjector
+	// Methods which must be reimplemented by all subclasses of StelProjector
 	//! Get a human-readable name for this projection type
 	virtual QString getNameI18() const = 0;
 	//! Get a human-readable short description for this projection type
@@ -164,7 +164,7 @@ class StelProjector
 	//! Apply the transformation in the backward projection in place.
 	virtual bool backward(Vec3d& v) const = 0;
 	//! Return the small zoom increment to use at the given FOV for nice movements
-	virtual float deltaZoom(float fov) const = 0;
+	virtual float deltaZoom(float fov) const {return fov;}
 	//! Returns GLSL code that can be used in a shader to implement forward transformation
 	virtual QByteArray getForwardTransformShader() const = 0;
 	//! Sets the necessary uniforms so that the shader returned by getForwardTransformShader can work
@@ -181,9 +181,9 @@ class StelProjector
 	bool intersectViewportDiscontinuity(const SphericalCap& cap) const;
 
 	//! Convert a Field Of View radius value in radians in ViewScalingFactor (used internally)
-	virtual float fovToViewScalingFactor(float fov) const = 0;
+	virtual float fovToViewScalingFactor(float fov) const {return fov;}
 	//! Convert a ViewScalingFactor value (used internally) in Field Of View radius in radians
-	virtual float viewScalingFactorToFov(float vsf) const = 0;
+	virtual float viewScalingFactorToFov(float vsf) const { return vsf;}
 
 	//! Get the current state of the flag which decides whether to
 	//! arrage labels so that they are aligned with the bottom of a 2d
@@ -347,19 +347,19 @@ class StelProjector
 		  widthStretch(1.0) {}
 
 	//! Return whether the projection presents discontinuities. Used for optimization.
-	virtual bool hasDiscontinuity() const =0;
+	virtual bool hasDiscontinuity() const {return false;}
 	//! Determine whether a great circle connection p1 and p2 intersects with a projection discontinuity.
 	//! For many projections without discontinuity, this should return always false, but for other like
 	//! cylindrical projection it will return true if the line cuts the wrap-around line (i.e. at lon=180 if the observer look at lon=0).
-	virtual bool intersectViewportDiscontinuityInternal(const Vec3d& p1, const Vec3d& p2) const = 0;
+	virtual bool intersectViewportDiscontinuityInternal(const Vec3d& p1, const Vec3d& p2) const {return false;}
 
 	//! Determine whether a cap intersects with a projection discontinuity.
-	virtual bool intersectViewportDiscontinuityInternal(const Vec3d& capN, double capD) const = 0;
+	virtual bool intersectViewportDiscontinuityInternal(const Vec3d& capN, double capD) const {return false;}
 
 	//! Initialize the bounding cap.
 	virtual void computeBoundingCap();
 
-	ModelViewTranformP modelViewTransform;	// Operator to apply (if not Q_NULLPTR) before the modelview projection step
+	ModelViewTranformP modelViewTransform;	// Operator to apply (if not nullptr) before the modelview projection step
 
 	float flipHorz,flipVert;            // Whether to flip in horizontal or vertical directions. Values only -1 (flip) or +1 (no flip).
 	float pixelPerRad;                  // pixel per rad at the center of the viewport disk