StelProjector Class Reference

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

#include <StelProjector.hpp>

List of all members.

Classes
class	Mat4dTransform
class	ModelViewTranform
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.
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.
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.
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.
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.
SphericalRegionP	getViewportConvexPolygon (float marginX=0., float marginY=0.) const
	Return a convex polygon on the sphere which includes the viewport in the current frame.
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.
bool	checkInViewport (const Vec3f &pos) const
	Check to see if a 2d position is inside the viewport.
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.
bool	project (const Vec3f &v, Vec3f &win) const
	Project the vector v from the current frame into the viewport.
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.
bool	projectInPlace (Vec3f &v) const
	Project the vector v from the current frame into the viewport.
bool	projectCheck (const Vec3d &v, Vec3d &win) const
	Project the vector v from the current frame into the viewport.
bool	projectCheck (const Vec3f &v, Vec3f &win) const
	Project the vector v from the current frame into the viewport.
bool	unProject (const Vec3d &win, Vec3d &v) const
	Project the vector v from the viewport frame into the current frame.
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.
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.
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
float	viewportFovDiameter
bool	gravityLabels
float	defautAngleForGravityText
SphericalCap	boundingCap

---

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 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 Typedef Documentation

StelProjector::ModelViewTranformP

Shared pointer on a ModelViewTranform instance (implement reference counting).

---

Member Enumeration Documentation

enum StelProjector::StelProjectorMaskType

Define viewport mask types.

Enumerator:

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

---

Constructor & Destructor Documentation

virtual StelProjector::~StelProjector

(

)

[inline, virtual]

Destructor.

StelProjector::StelProjector

(

ModelViewTranformP

amodelViewTransform

)

[inline, protected]

Private constructor. Only StelCore can create instances of StelProjector.

---

Member Function Documentation

virtual bool StelProjector::backward

(

Vec3d &

v

)

const [pure virtual]

Apply the transformation in the backward projection in place.

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

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

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

virtual void StelProjector::computeBoundingCap

(

)

[protected, virtual]

Initialize the bounding cap.

Reimplemented in StelProjector2d.

virtual float StelProjector::deltaZoom

(

float

fov

)

const [pure virtual]

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

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

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

virtual float StelProjector::fovToViewScalingFactor

(

float

fov

)

const [pure virtual]

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

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

const SphericalCap& StelProjector::getBoundingCap

(

)

const

Return a SphericalCap containing the whole viewport.

virtual QString StelProjector::getDescriptionI18

(

)

const [inline, virtual]

Get a human-readable short description for this projection type.

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

bool StelProjector::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.

float StelProjector::getFov

(

)

const

Get the current FOV diameter in degrees.

QString StelProjector::getHtmlSummary

(

)

const

Get a HTML version of the short description for this projection type.

StelProjectorMaskType StelProjector::getMaskType

(

void

)

const

Get the current type of the mask if any.

virtual float StelProjector::getMaxFov

(

)

const [pure virtual]

Get the maximum FOV apperture in degree.

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

ModelViewTranformP StelProjector::getModelViewTransform

(

)

const

Get the current model view matrix.

virtual QString StelProjector::getNameI18

(

)

const [pure virtual]

Get a human-readable name for this projection type.

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

float StelProjector::getPixelPerRadAtCenter

(

)

const

Get size of a radian in pixels at the center of the viewport disk.

Mat4f StelProjector::getProjectionMatrix

(

)

const

Get the current projection matrix.

const Vec4i& StelProjector::getViewport

(

)

const

Get the lower left corner of the viewport and the width, height.

Vec2f StelProjector::getViewportCenter

(

)

const

Get the center of the viewport relative to the lower left corner of the screen.

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).

int StelProjector::getViewportHeight

(

)

const

Get the viewport height in pixels.

int StelProjector::getViewportPosX

(

)

const

Get the horizontal viewport offset in pixels.

int StelProjector::getViewportPosY

(

)

const

Get the vertical viewport offset in pixels.

int StelProjector::getViewportWidth

(

)

const

Get the viewport width in pixels.

virtual bool StelProjector::hasDiscontinuity

(

)

const [protected, pure virtual]

Return whether the projection presents discontinuities. Used for optimization.

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

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).

virtual bool StelProjector::intersectViewportDiscontinuityInternal	(	const Vec3d &	capN,
		double	capD
	)			const [protected, pure virtual]

Determine whether a cap intersects with a projection discontinuity.

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

virtual bool StelProjector::intersectViewportDiscontinuityInternal	(	const Vec3d &	p1,
		const Vec3d &	p2
	)			const [protected, pure virtual]

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).

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

static const QString StelProjector::maskTypeToString

(

StelProjectorMaskType

type

)

[static]

Get a string description of a StelProjectorMaskType.

bool StelProjector::needGlFrontFaceCW

(

)

const

Get whether front faces need to be oriented in the clockwise direction.

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

Project the vector v from the current frame into the viewport.

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.

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

Project the vector v from the current frame into the viewport.

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.

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

Project the vector v from the current frame into the viewport.

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.

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

Project the vector v from the current frame into the viewport.

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.

bool StelProjector::projectInPlace

(

Vec3f &

v

)

const

Project the vector v from the current frame into the viewport.

Parameters:

v

the vector in the current frame.

Returns:

true if the projected coordinate is valid.

bool StelProjector::projectInPlace

(

Vec3d &

vd

)

const

Project the vector v from the current frame into the viewport.

Parameters:

vd

the vector in the current frame.

Returns:

true if the projected coordinate is valid.

bool StelProjector::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.

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.

static StelProjectorMaskType StelProjector::stringToMaskType

(

const QString &

s

)

[static]

Get a StelProjectorMaskType from a string description.

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

Project the vector v from the viewport frame into the current frame.

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.

Vec3d StelProjector::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).

virtual float StelProjector::viewScalingFactorToFov

(

float

vsf

)

const [pure virtual]

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

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