This class implements a finger-proxy force rendering algorithm. More...

#include <CAlgorithmFingerProxy.h>

Inheritance diagram for chai3d::cAlgorithmFingerProxy:

Public Member Functions
	cAlgorithmFingerProxy ()
	Constructor of cAlgorithmFingerProxy. More...

virtual	~cAlgorithmFingerProxy ()
	Destructor of cAlgorithmFingerProxy. More...

void	initialize (cWorld *a_world, const cVector3d &a_initialGlobalPosition)
	This method initialize the algorithm. More...

void	reset ()
	This method reset the algorithm and sets the proxy position to the device position. More...

virtual cVector3d	computeForces (const cVector3d &a_toolPos, const cVector3d &a_toolVel)
	This method calculates the interaction forces. More...

void	setProxyRadius (const double &a_radius)
	This method sets the radius of the proxy. More...

double	getProxyRadius () const
	This method returns the radius of the proxy. More...

cVector3d	getProxyGlobalPosition () const
	This method returns the last computed position of the proxy in world coordinates. More...

void	setProxyGlobalPosition (const cVector3d &a_position)
	This method sets the position of the proxy in world coordinates. More...

cVector3d	getDeviceGlobalPosition () const
	This method returns the last specified position of the device in world coordinates. More...

cVector3d	getForce ()
	This method returns the last computed force in world coordinates. More...

cVector3d	getNormalForce ()
	This method returns the most recently calculated normal force. More...

cVector3d	getTangentialForce ()
	This method returns the most recently calculated tangential force. More...

int	getNumCollisionEvents ()
	This method return the number of collision events (0, 1, 2 or 3): More...

void	setEpsilonBaseValue (double a_value)
	This method sets the epsilon tolerance error base value. More...

double	getEpsilonBaseValue ()
	This method returns the current epsilon tolerance error base value. More...

Public Member Functions inherited from chai3d::cGenericForceAlgorithm
	cGenericForceAlgorithm ()
	Constructor of cGenericForceAlgorithm. More...

virtual	~cGenericForceAlgorithm ()
	Destructor of cGenericForceAlgorithm. More...

cWorld *	getWorld ()
	This method returns a pointer to the world in which the force algorithm is operating. More...

void	setShowEnabled (bool a_showEnabled)

bool	getShowEnabled ()

Public Attributes
cCollisionEvent *	m_collisionEvents [3]
	Table of collision events (0-3). Call getNumCollisionEvents() to see how many are actually valid. More...

bool	m_useDynamicProxy
	If true the the dynamic proxy is enabled to handle moving objects. More...

double	m_frictionDynHysteresisMultiplier

double	m_forceShadingAngleThreshold
	Maximum force shading angle (radians) threshold between normals of triangle. More...

cCollisionSettings	m_collisionSettings
	Collision settings. More...

Protected Member Functions
virtual void	render (cRenderOptions &a_options)
	This method renders the force algorithms graphically in OpenGL. (For debug purposes) More...

virtual bool	goalAchieved (const cVector3d &a_proxy, const cVector3d &a_goal) const
	This method tests whether the proxy has reached the goal point. More...

virtual void	computeNextBestProxyPosition (const cVector3d &a_goal)
	This method computes the next goal position of the proxy. More...

virtual void	testFrictionAndMoveProxy (const cVector3d &a_goal, const cVector3d &a_proxy, cVector3d &a_normal, cGenericObject *a_parent)
	This method attempts to move the proxy, subject to friction constraints. More...

virtual void	updateForce ()
	This method computes the resulting force which will be sent to the haptic device. More...

void	adjustDynamicProxy (const cVector3d &a_goal)
	This method ajust the position of proxy by taking into account motion of objects in the world. More...

bool	computeNextProxyPositionWithContraints0 (const cVector3d &a_goalGlobalPos)
	This method updates the position of the proxy - constraint 0. More...

bool	computeNextProxyPositionWithContraints1 (const cVector3d &a_goalGlobalPos)
	This method updates the position of the proxy - constraint 1. More...

bool	computeNextProxyPositionWithContraints2 (const cVector3d &a_goalGlobalPos)
	This method updates the position of the proxy - constraint 2. More...

cVector3d	computeShadedSurfaceNormal (cCollisionEvent *a_contactPoint)
	This method computes the local surface normal from interpolated vertex normals. More...

Protected Attributes
cVector3d	m_proxyGlobalPos
	Global position of the proxy. More...

cVector3d	m_deviceGlobalPos
	Global position of device. More...

cVector3d	m_lastGlobalForce
	Last computed force (in global coordinate frame). More...

cVector3d	m_nextBestProxyGlobalPos
	Next best position for the proxy (in global coordinate frame). More...

bool	m_slipping
	If true then we are currently in a "slip friction". More...

cVector3d	m_normalForce
	Normal force. More...

cVector3d	m_tangentialForce
	Tangential force. More...

unsigned int	m_numCollisionEvents
	Number of collision events between proxy and triangles (0, 1, 2 or 3). More...

double	m_radius
	Radius of the proxy. More...

cCollisionRecorder	m_collisionRecorderConstraint0
	Collision detection recorder for searching first constraint. More...

cCollisionRecorder	m_collisionRecorderConstraint1
	Collision detection recorder for searching second constraint. More...

cCollisionRecorder	m_collisionRecorderConstraint2
	Collision detection recorder for searching third constraint. More...

cVector3d	m_contactPointLocalPos0
	Local position of contact point first object. More...

cVector3d	m_contactPointLocalPos1
	Local position of contact point first object. More...

cVector3d	m_contactPointLocalPos2
	Local position of contact point first object. More...

double	m_epsilonInitialValue
	Epsilon value - used for handling numerical limits. More...

double	m_epsilon
	Epsilon value - used for handling numerical limits. More...

double	m_epsilonCollisionDetection
	Epsilon value - used for handling numerical limits. More...

double	m_epsilonBaseValue
	Epsilon value - used for handling numerical limits. More...

double	m_epsilonMinimalValue
	Epsilon value - used for handling numerical limits. More...

unsigned int	m_algoCounter
	Value of state machine. More...

cVector3d	surfaceNormal
	Surface normal. More...

Protected Attributes inherited from chai3d::cGenericForceAlgorithm
cWorld *	m_world
	Pointer to the world in which the force algorithm operates. More...

bool	m_showEnabled
	If true then the graphic display mode is enabled. More...

Detailed Description

This class implements a finger-proxy force rendering algorithm for polygonal objects.

Constructor & Destructor Documentation

chai3d::cAlgorithmFingerProxy::cAlgorithmFingerProxy ( )

Constructor of cAlgorithmFingerProxy.

virtual chai3d::cAlgorithmFingerProxy::~cAlgorithmFingerProxy ( )

inlinevirtual

Member Function Documentation

void chai3d::cAlgorithmFingerProxy::initialize	(	cWorld *	a_world,
		const cVector3d &	a_initialGlobalPosition
	)

virtual

This method Initializes the algorithm, including setting the pointer to the world in which the algorithm is to operate, and setting the initial position of the device.

Parameters

a_world	Pointer to world in which force algorithm is operating.
a_initialGlobalPosition	Initial position of the haptic device.

Reimplemented from chai3d::cGenericForceAlgorithm.

void chai3d::cAlgorithmFingerProxy::reset ( )

This method reset the algorithm and sets the proxy position to the device position.

cVector3d chai3d::cAlgorithmFingerProxy::computeForces	(	const cVector3d &	a_toolPos,
		const cVector3d &	a_toolVel
	)

virtual

This method computes the interaction forces that are associated with the position of the device and the proxy.

Parameters

a_toolPos	New position of tool
a_toolVel	New velocity of tool

Returns: Haptic force.

Reimplemented from chai3d::cGenericForceAlgorithm.

void chai3d::cAlgorithmFingerProxy::setProxyRadius ( const double & a_radius )

inline

double chai3d::cAlgorithmFingerProxy::getProxyRadius ( ) const

inline

cVector3d chai3d::cAlgorithmFingerProxy::getProxyGlobalPosition ( ) const

inline

void chai3d::cAlgorithmFingerProxy::setProxyGlobalPosition ( const cVector3d & a_position )

inline

cVector3d chai3d::cAlgorithmFingerProxy::getDeviceGlobalPosition ( ) const

inline

cVector3d chai3d::cAlgorithmFingerProxy::getForce ( )

inline

cVector3d chai3d::cAlgorithmFingerProxy::getNormalForce ( )

inline

cVector3d chai3d::cAlgorithmFingerProxy::getTangentialForce ( )

inline

int chai3d::cAlgorithmFingerProxy::getNumCollisionEvents ( )

inline

void chai3d::cAlgorithmFingerProxy::setEpsilonBaseValue ( double a_value )

This method sets the epsilon value which is used during geometry computation of the proxy model.

double chai3d::cAlgorithmFingerProxy::getEpsilonBaseValue ( )

inline

void chai3d::cAlgorithmFingerProxy::render ( cRenderOptions & a_options )

protectedvirtual

This method render the force algorithm graphically using OpenGL.

Parameters

a_options Rendering options.

Reimplemented from chai3d::cGenericForceAlgorithm.

bool chai3d::cAlgorithmFingerProxy::goalAchieved	(	const cVector3d &	a_proxy,
		const cVector3d &	a_goal
	)		const

protectedvirtual

This method tests whether the proxy has reached the goal point, allowing for subclass-specific approximations.

Parameters

a_goal	The location to which we'd like to move the proxy.
a_proxy	The current position of the proxy.

Returns: true is the proxy has effectively reached the goal, false otherwise.

void chai3d::cAlgorithmFingerProxy::computeNextBestProxyPosition ( const cVector3d & a_goal )

protectedvirtual

Given the new position of the device and considering the current position of the proxy, this method attempts to move the proxy towards the device position (the goal). If its path is blocked by an obstacle (e.g., a triangle in a mesh), the proxy is moved to this intersection point and a new goal is calculated as the closest point to the original goal in the half-plane above the intersection triangle. The process is repeated if necessary, bringing the proxy to its final location.

Parameters

a_goal The goal position of the proxy subject to constraints.

void chai3d::cAlgorithmFingerProxy::testFrictionAndMoveProxy	(	const cVector3d &	a_goal,
		const cVector3d &	a_proxy,
		cVector3d &	a_normal,
		cGenericObject *	a_parent
	)

protectedvirtual

This method attempts to move the proxy, subject to friction constraints. This is called from computeNextBestProxyPosition() when the proxy is ready to move along a known surface.

Parameters

a_goal	The location to which we'd like to move the proxy.
a_proxy	The current position of the proxy.
a_normal	The surface normal at the obstructing surface.
a_parent	The surface along which we're moving.

void chai3d::cAlgorithmFingerProxy::updateForce ( )

protectedvirtual

This method uses the contact to determine the force to apply to the device. The function computes a force proportional to the distance between the positions of the proxy and the device and scaled by the average stiffness of each contact triangle.

void chai3d::cAlgorithmFingerProxy::adjustDynamicProxy ( const cVector3d & a_goal )

protected

bool chai3d::cAlgorithmFingerProxy::computeNextProxyPositionWithContraints0 ( const cVector3d & a_goalGlobalPos )

protected

bool chai3d::cAlgorithmFingerProxy::computeNextProxyPositionWithContraints1 ( const cVector3d & a_goalGlobalPos )

protected

bool chai3d::cAlgorithmFingerProxy::computeNextProxyPositionWithContraints2 ( const cVector3d & a_goalGlobalPos )

protected

cVector3d chai3d::cAlgorithmFingerProxy::computeShadedSurfaceNormal ( cCollisionEvent * a_contactPoint )

protected

This method computes the surface normal at the proxy position.

Parameters

a_contactPoint Position of proxy.

Returns: Surface normal.

Member Data Documentation

cCollisionEvent* chai3d::cAlgorithmFingerProxy::m_collisionEvents[3]

bool chai3d::cAlgorithmFingerProxy::m_useDynamicProxy

double chai3d::cAlgorithmFingerProxy::m_frictionDynHysteresisMultiplier

Dynamic friction hysteresis multiplier In CHAI's proxy, the angle computed from the coefficient is multiplied by this constant to avoid rapidly oscillating between slipping and sticking without having to turn the dynamic friction level way down.

double chai3d::cAlgorithmFingerProxy::m_forceShadingAngleThreshold

cCollisionSettings chai3d::cAlgorithmFingerProxy::m_collisionSettings

cVector3d chai3d::cAlgorithmFingerProxy::m_proxyGlobalPos

protected

cVector3d chai3d::cAlgorithmFingerProxy::m_deviceGlobalPos

protected

cVector3d chai3d::cAlgorithmFingerProxy::m_lastGlobalForce

protected

cVector3d chai3d::cAlgorithmFingerProxy::m_nextBestProxyGlobalPos

protected

bool chai3d::cAlgorithmFingerProxy::m_slipping

protected

cVector3d chai3d::cAlgorithmFingerProxy::m_normalForce

protected

cVector3d chai3d::cAlgorithmFingerProxy::m_tangentialForce

protected

unsigned int chai3d::cAlgorithmFingerProxy::m_numCollisionEvents

protected

double chai3d::cAlgorithmFingerProxy::m_radius

protected

cCollisionRecorder chai3d::cAlgorithmFingerProxy::m_collisionRecorderConstraint0

protected

cCollisionRecorder chai3d::cAlgorithmFingerProxy::m_collisionRecorderConstraint1

protected

cCollisionRecorder chai3d::cAlgorithmFingerProxy::m_collisionRecorderConstraint2

protected

cVector3d chai3d::cAlgorithmFingerProxy::m_contactPointLocalPos0

protected

cVector3d chai3d::cAlgorithmFingerProxy::m_contactPointLocalPos1

protected

cVector3d chai3d::cAlgorithmFingerProxy::m_contactPointLocalPos2

protected

double chai3d::cAlgorithmFingerProxy::m_epsilonInitialValue

protected

To address numerical errors during geometric computation, several epsilon values are computed and used.

double chai3d::cAlgorithmFingerProxy::m_epsilon

protected

double chai3d::cAlgorithmFingerProxy::m_epsilonCollisionDetection

protected

double chai3d::cAlgorithmFingerProxy::m_epsilonBaseValue

protected

double chai3d::cAlgorithmFingerProxy::m_epsilonMinimalValue

protected

unsigned int chai3d::cAlgorithmFingerProxy::m_algoCounter

protected

cVector3d chai3d::cAlgorithmFingerProxy::surfaceNormal

protected

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

Public Member Functions

Public Attributes

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation