Implementation of Ken Shoemake's arcball camera with smooth navigation. More...

#include <ArcBall.h>

Inheritance diagram for ArcBall:

Public Member Functions
	ArcBall (const Vector3 &cameraPosition, const Vector3 &viewCenter, const Vector3 &upDir, Deg fov, const Vector2i &windowSize)
	Constructs a new instance.

void	setViewParameters (const Vector3 &eye, const Vector3 &viewCenter, const Vector3 &upDir)
	Set the camera view parameters: eye position, view center, up direction.

void	reset ()
	Reset the camera to its initial position, view center, and up dir.

void	reshape (const Vector2i &windowSize)
	Update screen size after the window has been resized.

bool	updateTransformation ()
	Update any unfinished transformation due to lagging.

Float	lagging () const
	Get the amount of lagging such that the camera will (slowly) smoothly navigate.

void	setLagging (Float lagging)
	Set the amount of lagging such that the camera will (slowly) smoothly navigate. Lagging must be in [0, 1).

void	initTransformation (const Vector2i &mousePos)
	Initialize the first (screen) mouse position for camera transformation. This should be called from the mouse pressed event.

void	rotate (const Vector2i &mousePos)
	Rotate the camera from the previous (screen) mouse position to the current(screen) position.

void	translate (const Vector2i &mousePos)
	Translate the camera from the previous (screen) mouse position to the current(screen) mouse position.

void	translateDelta (const Vector2 &translationNDC)
	Translate the camera by the delta amount of (NDC) mouse position. Note that NDC position must be in[-1, -1] to[1, 1].

void	zoom (Float delta)
	Zoom the camera.

Deg	fov () const
	Field of view.

const DualQuaternion &	view () const
	Get the camera's view transformation as a dual quaternion.

Matrix4	viewMatrix () const
	Get the camera's view transformation as a matrix.

Matrix4	inverseViewMatrix () const
	Get the camera's inverse view matrix (which also produces transformation of the camera)

const DualQuaternion &	transformation () const
	Get the camera's transformation as a dual quaternion.

Matrix4	transformationMatrix () const
	Get the camera's transformation matrix.

Float	viewDistance () const
	Return the distance from the camera position to the center view.

Protected Member Functions
void	updateInternalTransformations ()
	Update the camera transformations-.

Vector2	screenCoordToNDC (const Vector2i &mousePos) const
	Transform from screen coordinate to NDC - normalized device coordinate. The top - left of the screen corresponds to[-1, 1] NDC, and the bottom right is[1, -1] NDC.

Protected Attributes
Deg	_fov

Vector2i	_windowSize

Vector2	_prevMousePosNDC

Float	_lagging {}

Vector3	_targetPosition

Vector3	_currentPosition

Vector3	_positionT0

Quaternion	_targetQRotation

Quaternion	_currentQRotation

Quaternion	_qRotationT0

Float	_targetZooming

Float	_currentZooming

Float	_zoomingT0

DualQuaternion	_view

DualQuaternion	_inverseView

Detailed Description

Implementation of Ken Shoemake's arcball camera with smooth navigation.

See also: : https://www.talisman.org/~erlkonig/misc/shoemake92-arcball.pdf

Constructor & Destructor Documentation

◆ ArcBall()

ArcBall::ArcBall	(	const Vector3 &	cameraPosition,
		const Vector3 &	viewCenter,
		const Vector3 &	upDir,
		Deg	fov,
		const Vector2i &	windowSize
	)

Constructs a new instance.

Parameters

cameraPosition	the position of the camera on the arc ball.
viewCenter	the position of the arc ball.
upDir	a vector representing the upwards direction.
fov	the fov of the camera.
windowSize	the size of the output window.

Member Function Documentation

◆ fov()

Deg ArcBall::fov ( ) const

inline

Field of view.

Returns: the field of view

◆ initTransformation()

void ArcBall::initTransformation ( const Vector2i & mousePos )

Initialize the first (screen) mouse position for camera transformation. This should be called from the mouse pressed event.

Parameters

mousePos the current mouse position.

◆ inverseViewMatrix()

Matrix4 ArcBall::inverseViewMatrix ( ) const

inline

Get the camera's inverse view matrix (which also produces transformation of the camera)

Returns: the camera's inverse view transformation

◆ lagging()

Float ArcBall::lagging ( ) const

inline

Get the amount of lagging such that the camera will (slowly) smoothly navigate.

Returns: the amount of lagging in [0, 1).

◆ reset()

void ArcBall::reset ( )

Reset the camera to its initial position, view center, and up dir.

◆ reshape()

void ArcBall::reshape ( const Vector2i & windowSize )

inline

Update screen size after the window has been resized.

Parameters

windowSize the new window size.

◆ rotate()

void ArcBall::rotate ( const Vector2i & mousePos )

Rotate the camera from the previous (screen) mouse position to the current(screen) position.

Parameters

mousePos the current mouse position.

◆ screenCoordToNDC()

Vector2 ArcBall::screenCoordToNDC ( const Vector2i & mousePos ) const

protected

Transform from screen coordinate to NDC - normalized device coordinate. The top - left of the screen corresponds to[-1, 1] NDC, and the bottom right is[1, -1] NDC.

Parameters

mousePos the mouse position in screen coordinates.

Returns: the given mouse position in normalized device coordinates

◆ setLagging()

void ArcBall::setLagging ( Float lagging )

Set the amount of lagging such that the camera will (slowly) smoothly navigate. Lagging must be in [0, 1).

◆ setViewParameters()

void ArcBall::setViewParameters	(	const Vector3 &	eye,
		const Vector3 &	viewCenter,
		const Vector3 &	upDir
	)

Set the camera view parameters: eye position, view center, up direction.

Parameters

eye	the position of the camera on the arc ball.
viewCenter	the position of the arc ball.
upDir	a vector representing the upwards direction.

◆ transformation()

const DualQuaternion & ArcBall::transformation ( ) const

inline

Get the camera's transformation as a dual quaternion.

Returns: the camera's transformation

◆ transformationMatrix()

Matrix4 ArcBall::transformationMatrix ( ) const

inline

Get the camera's transformation matrix.

Returns: the camera's transformation

◆ translate()

void ArcBall::translate ( const Vector2i & mousePos )

Translate the camera from the previous (screen) mouse position to the current(screen) mouse position.

Parameters

mousePos the current mouse position.

◆ translateDelta()

void ArcBall::translateDelta ( const Vector2 & translationNDC )

Translate the camera by the delta amount of (NDC) mouse position. Note that NDC position must be in[-1, -1] to[1, 1].

Parameters

translationNDC the translation amount.

◆ updateInternalTransformations()

void ArcBall::updateInternalTransformations ( )

protected

Update the camera transformations-.

◆ updateTransformation()

bool ArcBall::updateTransformation ( )

Update any unfinished transformation due to lagging.

Returns: true if the camera matrices have changed, false otherwise.

◆ view()

const DualQuaternion & ArcBall::view ( ) const

inline

Get the camera's view transformation as a dual quaternion.

Returns: the camera's view transformation

◆ viewDistance()

Float ArcBall::viewDistance ( ) const

inline

Return the distance from the camera position to the center view.

Returns: the distance from the camera position to the center view

◆ viewMatrix()

Matrix4 ArcBall::viewMatrix ( ) const

inline

Get the camera's view transformation as a matrix.

Returns: camera's view transformation

◆ zoom()

void ArcBall::zoom ( Float delta )

Zoom the camera.

Parameters

delta the amount of zoom (positive delta = zoom in, negative = zoom out)

Member Data Documentation

◆ _currentPosition

Vector3 ArcBall::_currentPosition

protected

◆ _currentQRotation

Quaternion ArcBall::_currentQRotation

protected

◆ _currentZooming

Float ArcBall::_currentZooming

protected

◆ _fov

Deg ArcBall::_fov

protected

◆ _inverseView

DualQuaternion ArcBall::_inverseView

protected

◆ _lagging

Float ArcBall::_lagging {}

protected

◆ _positionT0

Vector3 ArcBall::_positionT0

protected

◆ _prevMousePosNDC

Vector2 ArcBall::_prevMousePosNDC

protected

◆ _qRotationT0

Quaternion ArcBall::_qRotationT0

protected

◆ _targetPosition

Vector3 ArcBall::_targetPosition

protected

◆ _targetQRotation

Quaternion ArcBall::_targetQRotation

protected

◆ _targetZooming

Float ArcBall::_targetZooming

protected

◆ _view

DualQuaternion ArcBall::_view

protected

◆ _windowSize

Vector2i ArcBall::_windowSize

protected

◆ _zoomingT0

Float ArcBall::_zoomingT0

protected

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

src/arcball/ArcBall.h
src/arcball/ArcBall.cpp

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ ArcBall()

Member Function Documentation

◆ fov()

◆ initTransformation()

◆ inverseViewMatrix()

◆ lagging()

◆ reset()

◆ reshape()

◆ rotate()

◆ screenCoordToNDC()

◆ setLagging()

◆ setViewParameters()

◆ transformation()

◆ transformationMatrix()

◆ translate()

◆ translateDelta()

◆ updateInternalTransformations()

◆ updateTransformation()

◆ view()

◆ viewDistance()

◆ viewMatrix()

◆ zoom()

Member Data Documentation

◆ _currentPosition

◆ _currentQRotation

◆ _currentZooming

◆ _fov

◆ _inverseView

◆ _lagging

◆ _positionT0

◆ _prevMousePosNDC

◆ _qRotationT0

◆ _targetPosition

◆ _targetQRotation

◆ _targetZooming

◆ _view

◆ _windowSize

◆ _zoomingT0