Provide the main interface to all operations of projecting coordinates from sky to screen. More...

#include <StelProjector.hpp>

Data Structures
class	Mat4dTransform

class	ModelViewTranform
	Allows to define non linear operations in addition to the standard linear (Matrix 4d) ModelView transformation. More...

struct	StelProjectorParams
	Contains all the param needed to initialize a StelProjector. More...

Public Types
enum	StelProjectorMaskType { MaskNone , MaskDisk }
	Define viewport mask types. More...

typedef QSharedPointer< ModelViewTranform >	ModelViewTranformP
	Shared pointer on a ModelViewTranform instance (implement reference counting)

Public Member Functions
virtual	~StelProjector ()
	Destructor.

virtual QString	getNameI18 () const =0
	Get a human-readable name for this projection type.

virtual QString	getDescriptionI18 () const
	Get a human-readable short description for this projection type.

QString	getHtmlSummary () const
	Get a HTML version of the short description for this projection type.

virtual float	getMaxFov () const =0
	Get the maximum FOV aperture in degree.

virtual bool	forward (Vec3f &v) const =0
	Apply the transformation in the forward direction in place. More...

virtual bool	backward (Vec3d &v) const =0
	Apply the transformation in the backward projection in place.

virtual float	deltaZoom (float fov) const
	Return the small zoom increment to use at the given FOV for nice movements.

virtual QByteArray	getForwardTransformShader () const =0
	Returns GLSL code that can be used in a shader to implement forward transformation.

virtual void	setForwardTransformUniforms (QOpenGLShaderProgram &program) const
	Sets the necessary uniforms so that the shader returned by getForwardTransformShader can work.

virtual QByteArray	getBackwardTransformShader () const =0
	Returns GLSL code that can be used in a shader to implement backward transformation.

virtual void	setBackwardTransformUniforms (QOpenGLShaderProgram &program) const
	Sets the necessary uniforms so that the shader returned by getBackwardTransformShader can work.

bool	intersectViewportDiscontinuity (const Vec3d &p1, const Vec3d &p2) const
	Determine whether a great circle connection p1 and p2 intersects with a projection discontinuity. More...

bool	intersectViewportDiscontinuity (const SphericalCap &cap) const

virtual float	fovToViewScalingFactor (float fov) const
	Convert a Field Of View radius value in radians in ViewScalingFactor (used internally)

virtual float	viewScalingFactorToFov (float vsf) const
	Convert a ViewScalingFactor value (used internally) in Field Of View radius in radians.

bool	getFlagGravityLabels () const
	Get the current state of the flag which decides whether to arrange labels so that they are aligned with the bottom of a 2d screen, or a 3d dome.

const Vec4i &	getViewport () const
	Get the lower left corner of the viewport and the width, height.

Vector2< qreal >	getViewportCenter () const
	Get the center of the viewport relative to the lower left corner of the screen.

Vector2< qreal >	getViewportCenterOffset () const

int	getViewportPosX () const
	Get the horizontal viewport offset in pixels.

int	getViewportPosY () const
	Get the vertical viewport offset in pixels.

int	getViewportWidth () const
	Get the viewport width in pixels.

int	getViewportHeight () const
	Get the viewport height in pixels.

qreal	getDevicePixelsPerPixel () const
	Get the number of device pixels per "Device Independent Pixels" (value is usually 1, but 2 for mac retina screens).

SphericalRegionP	getViewportConvexPolygon (float marginX=0., float marginY=0.) const
	Return a convex polygon on the sphere which includes the viewport in the current frame. More...

const SphericalCap &	getBoundingCap () const
	Return a SphericalCap containing the whole viewport.

float	getPixelPerRadAtCenter () const
	Get size of a radian in pixels at the center of the viewport disk.

float	getFov () const
	Get the current FOV diameter in degrees.

bool	needGlFrontFaceCW () const
	Get whether front faces need to be oriented in the clockwise direction.

bool	checkInViewport (const Vec3d &pos) const
	Check to see if a 2d position is inside the viewport. More...

bool	checkInViewport (const Vec3f &pos) const
	Check to see if a 2d position is inside the viewport. More...

Vec3d	viewPortIntersect (const Vec3d &p1, const Vec3d &p2) const
	Return the position where the 2 2D point p1 and p2 cross the viewport edge P1 must be inside the viewport and P2 outside (check with checkInViewport() before calling this method)

bool	project (const Vec3d &v, Vec3d &win) const
	Project the vector v from the current frame into the viewport. More...

bool	project (const Vec3f &v, Vec3f &win) const
	Project the vector v from the current frame into the viewport. More...

bool	project (const Vec3d &v, Vec3f &win) const
	Project the vector v from the current frame into the viewport. More...

virtual void	project (int n, const Vec3d in, Vec3f out)

virtual void	project (int n, const Vec3f in, Vec3f out)

bool	projectInPlace (Vec3d &vd) const
	Project the vector v from the current frame into the viewport. More...

bool	projectInPlace (Vec3f &v) const
	Project the vector v from the current frame into the viewport. More...

bool	projectCheck (const Vec3d &v, Vec3d &win) const
	Project the vector v from the current frame into the viewport. More...

bool	projectCheck (const Vec3f &v, Vec3f &win) const
	Project the vector v from the current frame into the viewport. More...

bool	unProject (const Vec3d &win, Vec3d &v) const
	Project the vector v from the viewport frame into the current frame. More...

bool	unProject (double x, double y, Vec3d &v) const

bool	projectLineCheck (const Vec3d &v1, Vec3d &win1, const Vec3d &v2, Vec3d &win2) const
	Project the vectors v1 and v2 from the current frame into the viewport. More...

QByteArray	getProjectShader () const

void	setProjectUniforms (QOpenGLShaderProgram &program) const

QByteArray	getUnProjectShader () const

void	setUnProjectUniforms (QOpenGLShaderProgram &program) const

ModelViewTranformP	getModelViewTransform () const
	Get the current model view matrix.

Mat4f	getProjectionMatrix () const
	Get the current projection matrix.

StelProjectorMaskType	getMaskType (void) const
	Get the current type of the mask if any.

bool	isSameProjection (const StelProjector &other) const
	Check whether the projection represented by `other` is the same as this. More...

Static Public Member Functions
static const QString	maskTypeToString (StelProjectorMaskType type)
	Get a string description of a StelProjectorMaskType.

static StelProjectorMaskType	stringToMaskType (const QString &s)
	Get a StelProjectorMaskType from a string description.

Protected Member Functions
	StelProjector (ModelViewTranformP amodelViewTransform)
	Private constructor. Only StelCore can create instances of StelProjector.

virtual bool	hasDiscontinuity () const
	Return whether the projection presents discontinuities. Used for optimization.

virtual bool	intersectViewportDiscontinuityInternal (const Vec3d &p1, const Vec3d &p2) const
	Determine whether a great circle connection p1 and p2 intersects with a projection discontinuity. More...

virtual bool	intersectViewportDiscontinuityInternal (const Vec3d &capN, double capD) const
	Determine whether a cap intersects with a projection discontinuity.

virtual void	computeBoundingCap ()
	Initialize the bounding cap.

Protected Attributes
ModelViewTranformP	modelViewTransform

float	flipHorz

float	flipVert

float	pixelPerRad

StelProjectorMaskType	maskType

double	zNear

double	oneOverZNearMinusZFar

Vec4i	viewportXywh

Vector2< qreal >	viewportCenter

Vector2< qreal >	viewportCenterOffset

qreal	viewportFovDiameter

bool	gravityLabels

float	defaultAngleForGravityText

SphericalCap	boundingCap

qreal	devicePixelsPerPixel

qreal	widthStretch

Friends
class	StelPainter

class	StelCore

Detailed Description

Provide the main interface to all operations of projecting coordinates from sky to screen.

The StelProjector also defines the viewport size and position. All positions in pixels are in real device pixels, which is not the same as device independent pixels. On a mac with retina screen, there are 2 device pixels per pixels. All methods from this class are threadsafe. The usual usage is to create local instances of StelProjectorP using the getProjection() method from StelCore where needed. For performing drawing using a particular projection, refer to the StelPainter class.

See also: StelProjectorP

Member Enumeration Documentation

◆ StelProjectorMaskType

enum StelProjector::StelProjectorMaskType

Define viewport mask types.

Enumerator
MaskNone	Regular - no mask.
MaskDisk	For disk viewport mode (circular mask to seem like bins/telescope)

Member Function Documentation

◆ checkInViewport() [1/2]

bool StelProjector::checkInViewport ( const Vec3d & pos ) const

Check to see if a 2d position is inside the viewport.

TODO Optimize by storing viewportXywh[1] + viewportXywh[3] and viewportXywh[0] + viewportXywh[2] already computed

◆ checkInViewport() [2/2]

bool StelProjector::checkInViewport ( const Vec3f & pos ) const

Check to see if a 2d position is inside the viewport.

TODO Optimize by storing viewportXywh[1] + viewportXywh[3] and viewportXywh[0] + viewportXywh[2] already computed

◆ forward()

virtual bool StelProjector::forward ( Vec3f & v ) const

pure virtual

Apply the transformation in the forward direction in place.

After transformation v[2] will always contain the length of the original v: sqrt(v[0]*v[0]+v[1]*v[1]+v[2]*v[2]) regardless of the projection type. This makes it possible to implement depth buffer testing in a way independent of the projection type. I would like to return the squared length instead of the length because of performance reasons. But then far away objects are not textured any more, perhaps because of a depth buffer overflow although the depth test is disabled?

Implemented in StelProjector2d, StelProjectorMiller, StelProjectorSinusoidal, StelProjectorOrthographic, StelProjectorMercator, StelProjectorCylinder, StelProjectorHammer, StelProjectorFisheye, StelProjectorStereographic, StelProjectorEqualArea, and StelProjectorPerspective.

◆ getViewportConvexPolygon()

SphericalRegionP StelProjector::getViewportConvexPolygon	(	float	marginX = `0.`,
		float	marginY = `0.`
	)		const

Return a convex polygon on the sphere which includes the viewport in the current frame.

Parameters

marginX	an extra margin in pixel which extends the polygon size in the X direction.
marginY	an extra margin in pixel which extends the polygon size in the Y direction.

Returns: a SphericalConvexPolygon or the special fullSky region if the viewport cannot be represented by a convex polygon (e.g. if aperture > 180 deg).

◆ intersectViewportDiscontinuity()

bool StelProjector::intersectViewportDiscontinuity	(	const Vec3d &	p1,
		const Vec3d &	p2
	)		const

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).

◆ intersectViewportDiscontinuityInternal()

virtual bool StelProjector::intersectViewportDiscontinuityInternal	(	const Vec3d &	p1,
		const Vec3d &	p2
	)		const

inlineprotectedvirtual

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).

Reimplemented in StelProjectorMercator, StelProjectorCylinder, StelProjectorHammer, and StelProjector2d.

◆ isSameProjection()

bool StelProjector::isSameProjection ( const StelProjector & other ) const

Check whether the projection represented by other is the same as this.

This check is intended to tell whether the shaders returned by #getProjectShader and #getUnProjectShader are the same for this and other. The parameters compared include projection type and whether refraction is on. Numerical