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 apperture 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 =0
	Return the small zoom increment to use at the given FOV for nice movements.

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 =0
	Convert a Field Of View radius value in radians in ViewScalingFactor (used internally)

virtual float	viewScalingFactorToFov (float vsf) const =0
	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 arrage labels so that they are aligned with the bottom of a 2d screen, or a 3d dome. More...

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

Vec2f	getViewportCenter () const
	Get the center of the viewport relative to the lower left corner of the screen.

Vec2f	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.

float	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...

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...

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.

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 =0
	Return whether the projection presents discontinuities. Used for optimization.

virtual bool	intersectViewportDiscontinuityInternal (const Vec3d &p1, const Vec3d &p2) const =0
	Determine whether a great circle connection p1 and p2 intersects with a projection discontinuity. More...

virtual bool	intersectViewportDiscontinuityInternal (const Vec3d &capN, double capD) const =0
	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

float	zNear

float	oneOverZNearMinusZFar

Vec4i	viewportXywh

Vec2f	viewportCenter

Vec2f	viewportCenterOffset

float	viewportFovDiameter

bool	gravityLabels

float	defaultAngleForGravityText

SphericalCap	boundingCap

float	devicePixelsPerPixel

float	widthStretch

Friends
class	StelPainter

class	StelCore

Detailed Description

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

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

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

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

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.

◆ getFlagGravityLabels()

bool StelProjector::getFlagGravityLabels ( ) const

◆ getViewportConvexPolygon()

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

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

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

protectedpure virtual

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).

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

◆ project() [1/2]

bool StelProjector::project	(	const Vec3d &	v,
		Vec3d &	win
	)		const

Parameters

v	the vector in the current frame.
win	the projected vector in the viewport 2D frame.

Returns: true if the projected coordinate is valid.

◆ project() [2/2]

bool StelProjector::project	(	const Vec3f &	v,
		Vec3f &	win
	)		const

Parameters

v	the vector in the current frame.
win	the projected vector in the viewport 2D frame.

Returns: true if the projected coordinate is valid.

◆ projectCheck() [1/2]

bool StelProjector::projectCheck	(	const Vec3d &	v,
		Vec3d &	win
	)		const

Parameters

v	the direction vector in the current frame. Does not need to be normalized.
win	the projected vector in the viewport 2D frame. win[0] and win[1] are in screen pixels, win[2] is unused.

Returns: true if the projected point is inside the viewport.

◆ projectCheck() [2/2]

bool StelProjector::projectCheck	(	const Vec3f &	v,
		Vec3f &	win
	)		const

Parameters

v	the direction vector in the current frame. Does not need to be normalized.
win	the projected vector in the viewport 2D frame. win[0] and win[1] are in screen pixels, win[2] is unused.

Returns: true if the projected point is inside the viewport.

◆ projectInPlace() [1/2]

bool StelProjector::projectInPlace ( Vec3d & vd ) const

Parameters

vd	the vector in the current frame.

Returns: true if the projected coordinate is valid.

◆ projectInPlace() [2/2]

bool StelProjector::projectInPlace ( Vec3f & v ) const

Parameters

v	the vector in the current frame.

Returns: true if the projected coordinate is valid.

◆ projectLineCheck()

bool StelProjector::projectLineCheck	(	const Vec3d &	v1,
		Vec3d &	win1,
		const Vec3d &	v2,
		Vec3d &	win2
	)		const

Parameters

v1	the first vector in the current frame.
v2	the second vector in the current frame.
win1	the first projected vector in the viewport 2D frame.
win2	the second projected vector in the viewport 2D frame.

Returns: true if at least one of the projected vector is within the viewport.

◆ unProject()

bool StelProjector::unProject	(	const Vec3d &	win,
		Vec3d &	v
	)		const

Parameters

win	the vector in the viewport 2D frame. win[0] and win[1] are in screen pixels, win[2] is unused.
v	the unprojected direction vector in the current frame.

Returns: true if the projected coordinate is valid.

Data Structures

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Friends

Detailed Description

Member Enumeration Documentation

◆ StelProjectorMaskType

Member Function Documentation

◆ checkInViewport() [1/2]

◆ checkInViewport() [2/2]

◆ forward()

◆ getFlagGravityLabels()

◆ getViewportConvexPolygon()

◆ intersectViewportDiscontinuity()

◆ intersectViewportDiscontinuityInternal()

◆ project() [1/2]

◆ project() [2/2]

◆ projectCheck() [1/2]

◆ projectCheck() [2/2]

◆ projectInPlace() [1/2]

◆ projectInPlace() [2/2]

◆ projectLineCheck()

◆ unProject()