vcg::PathMode Class Reference

The path constrained manipulator. More...

#include <trackmode.h>

Inheritance diagram for vcg::PathMode:

Public Member Functions
void	Apply (Trackball *trackball, float WheelNotch)
	Apply a translation, function of the user mouse wheel action.
void	Apply (Trackball *trackball, Point3f new_point)
	Apply a translation, function of the user mouse drag action.
void	Draw (Trackball *trackball)
	Render this manipulator.
bool	isSticky ()
	The (non) avaibility to manipulator changes inside an action.
const char *	Name ()
	Return this manipulator's name.
	PathMode (const Point3f &start, const Point3f &end)
	The segment constructor.
	PathMode (const std::vector< Point3f > &pts, bool w=false)
	The vector-boolean constructor.
void	Reset ()
	The reset function.
void	SetAction ()
	The begin action function.
Point3f	SetStartNear (Point3f p)
	Try to set the inital point.
void	Undo ()
	The undo function.
Private Member Functions
void	GetPoints (float state, Point3f &point, Point3f &prev_point, Point3f &next_point)
	The state interpreter.
float	HitPoint (float state, Ray3fN ray, Point3f &hit_point)
	Compute the new point and the $\Delta$ -state.
void	Init (const std::vector< Point3f > &points)
	The data initializer.
float	Normalize (float state)
	The state normalizer.
int	Verse (Point3f reference_point, Point3f current_point, Point3f prev_point, Point3f next_point)
	Compute the verse to follow for slide nearer to a given point.
Private Attributes
float	current_state
	The current state.
float	initial_state
	The initial state.
float	min_seg_length
	The length of the shostest path segment.
Point3f	old_hitpoint
	The point relative to the old state.
float	path_length
	The path length.
std::vector< Point3f >	points
	The node vector.
float	undo_current_state
	current_state after an Undo() call.
Point3f	undo_old_hitpoint
	old_hitpoint after an Undo() call.
bool	wrap
	True if the path is closed, false otherwise.

Detailed Description

The path constrained manipulator.

This manipulator moves the object along an eventually closed path.

The user can either drag the mouse or scroll the wheel, when the user drags the mouse, the object tries to slide toward it.

The object is assumed to initially be on the same position of the first point on the path.

This is a stateful manipulator, result of the Apply functions is determined by the objects's position along the path and by either the mouse coordinates or the mouse wheel notch.

Definition at line 649 of file trackmode.h.

Constructor & Destructor Documentation

vcg::PathMode::PathMode	(	const std::vector< Point3f > &	pts,
		bool	w = `false`
	)			`[inline]`

The vector-boolean constructor.

The vector passed to build the path is copied locally. The boolean value specifies if the path is to be closed. If the boolean value is not specified, the path is not closed.

Warning:: the path is not assumed to have 0-length segments, so, if you want to close the path, please do not add a copy of the first point on the end of the vector.

Parameters:

	pts	the path nodes.
	w	a boolean value that closes the path.

Definition at line 663 of file trackmode.h.

vcg::PathMode::PathMode	(	const Point3f &	start,
		const Point3f &	end
	)			`[inline]`

The segment constructor.

If the path is a simple segment, it can be specified just with the endpoints.

Parameters:

	start	the starting point.
	end	the ending point.

Definition at line 677 of file trackmode.h.

Member Function Documentation

void PathMode::Apply	(	Trackball *	trackball,
		float	WheelNotch
	)			`[virtual]`

Apply a translation, function of the user mouse wheel action.

The manipulated object is moved along the path. A step of the mouse wheel makes the object slide by a distance equal to the half of the shortest segment on the path.

Parameters:

	trackball	the manipulator manager.
	WheelNotch	the mouse wheel notch.

Reimplemented from vcg::TrackMode.

Definition at line 449 of file trackmode.cpp.

void PathMode::Apply	(	Trackball *	trackball,
		Point3f	new_point
	)			`[virtual]`

Apply a translation, function of the user mouse drag action.

The manipulated object is moved along the path. This function implements an algorithm that makes the object try to slide on the path towards the mouse pointer.

Parameters:

	trackball	the manipulator manager.
	new_point	the new mouse pointer coordinate.

Reimplemented from vcg::TrackMode.

Definition at line 541 of file trackmode.cpp.

void PathMode::Draw ( Trackball * trackball ) [virtual]

Render this manipulator.

Parameters:

trackball

the manipulator manager.

Reimplemented from vcg::TrackMode.

Definition at line 562 of file trackmode.cpp.

void PathMode::GetPoints	(	float	state,
		Point3f &	point,
		Point3f &	prev_point,
		Point3f &	next_point
	)			`[private]`

The state interpreter.

Given the state, return the current point, the previous node and the next node on the path. The algoritm is linear in the node paths.

Parameters:

	state	the given state.
	point	is set to the current point.
	prev_point	is set to the point of current point's previous node.
	next_point	is set to the point of current point's next node.

Definition at line 389 of file trackmode.cpp.

float PathMode::HitPoint	(	float	state,
		Ray3fN	ray,
		Point3f &	hit_point
	)			`[private]`

Compute the new point and the $\Delta$ -state.

Given a state and the mouse coords ray, computes the new state point and return the $\Delta$ -state. The algoritm is linear in the node paths.

Parameters:

	state	the given state.
	ray	the ray relative to mouse coords.
	hit_point	is set to the new state point.

Returns:: the $\Delta$ -state.

Definition at line 511 of file trackmode.cpp.

void PathMode::Init ( const std::vector< Point3f > & points ) [private]

The data initializer.

Initialize the internal state and checks params validity.

Parameters:

points

the path nodes.

Definition at line 322 of file trackmode.cpp.

bool PathMode::isSticky ( ) [virtual]

The (non) avaibility to manipulator changes inside an action.

This manipulator has an internal state and does not allow a switch in the middle of a function.

Returns:: the costant boolean true.

Reimplemented from vcg::TrackMode.

Definition at line 553 of file trackmode.cpp.

const char* vcg::PathMode::Name ( ) [inline, virtual]

Return this manipulator's name.

Returns:: the constant string "PathMode"

Reimplemented from vcg::TrackMode.

Definition at line 691 of file trackmode.h.

float PathMode::Normalize ( float state ) [private]

The state normalizer.

Normalize a given state in the right interval:

$[0 \ldots 1]$ if the path is open.
$[0 \ldots 1)$ if the path is closed (because it wraps).

Parameters:

state

the given state.

Definition at line 463 of file trackmode.cpp.

void PathMode::Reset ( ) [virtual]

The reset function.

This function reset the object position to the initial point.

Reimplemented from vcg::TrackMode.

Definition at line 345 of file trackmode.cpp.

void PathMode::SetAction ( ) [virtual]

The begin action function.

This function is to be called at the begin of an user action.

Reimplemented from vcg::TrackMode.

Definition at line 536 of file trackmode.cpp.

Point3f PathMode::SetStartNear ( Point3f p )

Try to set the inital point.

This function try to set the starting point in the point passed as parameter, if the point passed does not reside on the path, the start is put on the closest point on it.

Parameters:

p

the point wished for the start.

Returns:: the starting point on the path.

Definition at line 350 of file trackmode.cpp.

void PathMode::Undo ( ) [virtual]

The undo function.

This function recreates the state present before the last Apply() call.

Reimplemented from vcg::TrackMode.

Definition at line 557 of file trackmode.cpp.

int PathMode::Verse	(	Point3f	reference_point,
		Point3f	current_point,
		Point3f	prev_point,
		Point3f	next_point
	)			`[private]`

Compute the verse to follow for slide nearer to a given point.

Given the current state point, the point of previus and next node and a reference point, compute the verse to follow for the object to come closer to the reference point.

Parameters: