The TrackBall class implements a trackball camera. More...

#include <vclib/render/viewer/trackball.h>

Classes
struct	TransformArgs

Public Types
enum	MotionType { ARC , PAN , ZMOVE , ROLL , SCALE , FOV , FOCUS , DIR_LIGHT_ARC , MOTION_NUMBER }

using	AtomicMotionArg = std::variant< TransformArgs, Scalar, Point3< Scalar >, std::monostate >

Public Member Functions
void	reset ()

void	reset (const Point3< Scalar > &center, Scalar scale)
	Reset the manipulator to a given center and scale.

void	resetDirectionalLight ()

Point3< Scalar >	center () const

void	setCenter (const Point3< Scalar > &center)

Scalar	scale () const

void	setScale (Scalar scale)

void	changeScale (Scalar factor)

void	setRotation (const Quaternion< Scalar > &rotation)

void	setRotation (const Point3< Scalar > &axis, Scalar angle)

Scalar	fovDeg () const
	Get the vertical field of view.

void	setFovDeg (Scalar fov)
	Set the vertical field of view adapting the eye distance.

Camera< Scalar >::ProjectionMode::Enum	projectionMode () const

void	setProjectionMode (Camera< Scalar >::ProjectionMode::Enum mode)

void	setScreenSize (Scalar width, Scalar height)

void	setScreenSize (const Point2< Scalar > &sz)

DirectionalLight< Scalar >	light () const

const vcl::Camera< Scalar > &	camera () const

Matrix44< Scalar >	viewMatrix () const

Matrix44< Scalar >	projectionMatrix () const

Matrix44< Scalar >	gizmoMatrix () const

Matrix44< Scalar >	lightGizmoMatrix () const

bool	isDragging () const

MotionType	currentMotion () const

void	applyAtomicMotion (MotionType motion, AtomicMotionArg step=std::monostate())
	Applies an atomic motion to the trackball. Atomic motions are motions that are applied atomically to the camera. The step parameter is a std::variant that can store different values depending on the motion type.

void	applyScale (Scalar value)

void	applyRoll (Scalar angleRad)

void	applyPan (const Point3< Scalar > &translation)

void	applyArc (const Point3< Scalar > &axis, Scalar angle)

void	setMousePosition (Scalar x, Scalar y)

void	setMousePosition (const Point2< Scalar > &point)

void	beginDragMotion (MotionType motion)
	Starts a drag motion.

void	endDragMotion (MotionType motion)
	Ends a drag motion.

void	update ()
	Updates the state of the trackball during a drag motion.

Private Member Functions
void	setDragMotionValue (MotionType motion, bool value)

void	drag (MotionType motion)

Scalar	trackballToPixelRatio () const

Point3< Scalar >	pointOnTrackballPlane (Point2< Scalar > screenCoord) const

Point3< Scalar >	pointOnArcball (Point2< Scalar > screenCoord) const

void	rotate (const Quaternion< Scalar > &q)

void	rotate (Point3< Scalar > axis, Scalar angleRad)

void	translate (Point3< Scalar > t)
	Translate in the camera space.

void	rotateDirLight (const Quaternion< Scalar > &rotation)

void	rotateDirLight (Point3< Scalar > axis, Scalar angle)

void	dragArc ()

void	roll (Scalar delta)

void	dragRoll ()

void	performPan (const Point2< Scalar > &pixelDelta)
	perform a pan operation

void	dragPan ()

void	performZmove (const Scalar &pixelDelta)
	translate in the camera z direction

void	dragZmove ()

void	performScale (Scalar pixelDelta)

void	dragScale ()

void	dragDirLightArc ()

void	performFov (Scalar pixelDelta)

Private Attributes
Camera< Scalar >	mCamera

Affine3< Scalar >	mTransform = Affine3<Scalar>::Identity()

Quaternion< Scalar >	mDirectionalLightTransform

Point2< Scalar >	mScreenSize = {-1, -1}

Scalar	mRadius = ARC_BALL_RADIUS_RATIO

bool	mDragging = false

MotionType	mCurrDragMotion = MOTION_NUMBER

Point3< Scalar >	mInitialPoint

Affine3< Scalar >	mInitialTransform = Affine3<Scalar>::Identity()

Quaternion< Scalar >	mInitialDirRotation = Quaternion<Scalar>::Identity()

Point2< Scalar >	mCurrMousePosition

Point2< Scalar >	mPrevMousePosition

Static Private Attributes
static constexpr Scalar	ARC_BALL_RADIUS_RATIO = 1.0 / 1.61803398875

static constexpr Scalar	FOCUS_SCALE_FACTOR = 1.15

static constexpr Scalar	DEFAULT_FOV_DEG = 54.0

Detailed Description

template<typename Scalar>
class vcl::TrackBall< Scalar >

The TrackBall class implements a trackball camera.

The trackball class stores a camera and provides a set motions that allow the user to manipulate it.

There are two main types of motions:

atomic motions: these motions have no state and they are applied atomicly to the camera. They are not affected by the mouse position. An example of an atomic motion is a zoom.
drag motions: these motions have a state, that may change with the mouse position. They begin and end with the begin/end member functions, and they update their state trough the change of the mouse position. An example of a drag motion is an arcball rotation.

Member Function Documentation

◆ applyAtomicMotion()

template<typename Scalar >

void vcl::TrackBall< Scalar >::applyAtomicMotion	(	MotionType	motion,
		AtomicMotionArg	step = `std::monostate()`
	)

inline

Applies an atomic motion to the trackball. Atomic motions are motions that are applied atomically to the camera. The step parameter is a std::variant that can store different values depending on the motion type.

Possible motion types and supported step values are:

ROLL:
- Scalar (positive counter-clockwise roll, negative otherwise)
SCALE:
- Scalar (positive zoom in, negative zoom out)
ARC:
- TransformArgs (axis, angle) rotation along axis by angle
PAN:
- Point3 translation in trackball camera space
ZMOVE:
- Scalar z translation in trackball camera space
FOCUS:
- Point3 set center in world space
  Parameters
  
  motion
  
  step

◆ beginDragMotion()

template<typename Scalar >

void vcl::TrackBall< Scalar >::beginDragMotion ( MotionType motion )

inline

Starts a drag motion.

Parameters

[in] motion the motion type

Note: this function should be called when the drag motion begins (e.g., the mouse is pressed) or the motion type changes.

◆ dragArc()

template<typename Scalar >

void vcl::TrackBall< Scalar >::dragArc ( )

inlineprivate

— User interaction functions — -----------— Arc -----------—

◆ dragDirLightArc()

template<typename Scalar >

void vcl::TrackBall< Scalar >::dragDirLightArc ( )

inlineprivate

--— Directional Light Arc --—

◆ endDragMotion()

template<typename Scalar >

void vcl::TrackBall< Scalar >::endDragMotion ( MotionType motion )

inline

Ends a drag motion.

Parameters

[in] motion the motion type

Note: this function should be called when the drag motion ends (e.g., the mouse is released)

◆ performFov()

template<typename Scalar >

void vcl::TrackBall< Scalar >::performFov ( Scalar pixelDelta )

inlineprivate

--— Fov --—

◆ performPan()

template<typename Scalar >

void vcl::TrackBall< Scalar >::performPan ( const Point2< Scalar > & pixelDelta )

inlineprivate

perform a pan operation

-----------— Pan -----------—

Parameters

pixelDelta the pan movement in pixels

◆ performScale()

template<typename Scalar >

void vcl::TrackBall< Scalar >::performScale ( Scalar pixelDelta )

inlineprivate

-----------— Scaling -----------—

◆ performZmove()

template<typename Scalar >

void vcl::TrackBall< Scalar >::performZmove ( const Scalar & pixelDelta )

inlineprivate

translate in the camera z direction

-----------— Z-Move -----------—

Parameters

pixelDelta the delta movement in pixels

◆ reset()

template<typename Scalar >

void vcl::TrackBall< Scalar >::reset	(	const Point3< Scalar > &	center,
		Scalar	scale
	)

inline

Reset the manipulator to a given center and scale.

Parameters

center
scale

◆ roll()

template<typename Scalar >

void vcl::TrackBall< Scalar >::roll ( Scalar delta )

inlineprivate

-----------— Roll -----------—

◆ rotate()

template<typename Scalar >

void vcl::TrackBall< Scalar >::rotate ( const Quaternion< Scalar > & q )

inlineprivate

------— Base functions ------—

◆ setDragMotionValue()

template<typename Scalar >

void vcl::TrackBall< Scalar >::setDragMotionValue	(	MotionType	motion,
		bool	value
	)

inlineprivate

-----------— Generic Functions -----------—

◆ setFovDeg()

template<typename Scalar >

void vcl::TrackBall< Scalar >::setFovDeg ( Scalar fov )

inline

Set the vertical field of view adapting the eye distance.

Parameters

[in] fov the field of view in degrees.

◆ translate()

template<typename Scalar >

void vcl::TrackBall< Scalar >::translate ( Point3< Scalar > t )

inlineprivate

Translate in the camera space.

Note: from the trackball center Y range is [-1, 1] and X is [-aspectRatio, aspectRatio]

◆ update()

template<typename Scalar >

void vcl::TrackBall< Scalar >::update ( )

inline

Updates the state of the trackball during a drag motion.

Note: : this member function must be called only when a drag motion is in progress (e.g., when the mouse is dragging);

The documentation for this class was generated from the following file:

vclib/render/include/vclib/render/viewer/trackball.h

Classes

Public Types

Public Member Functions

Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

Member Function Documentation

◆ applyAtomicMotion()

◆ beginDragMotion()

◆ dragArc()

◆ dragDirLightArc()

◆ endDragMotion()

◆ performFov()

◆ performPan()

◆ performScale()

◆ performZmove()

◆ reset()

◆ roll()

◆ rotate()

◆ setDragMotionValue()

◆ setFovDeg()

◆ translate()

◆ update()