FiberLocus Class Reference

Detailed Description

FiberLocus is used to refer to the entire segment of a Fiber.

It is used to calculate the distance to this segment, or the intersection of the segment with a plane.

The only mysterious thing is the name: why Locus?

Public Member Functions
	FiberLocus ()
	construct without initialization
	FiberLocus (Fiber const *f, int r)
	constructor
Fiber const *	fiber () const
	the Fiber
unsigned int	point () const
	index of segment
real	len () const
	the length of the segment
Vector	pos1 () const
	position of first point in space
Vector	pos2 () const
	position of second point in space
Vector	diff () const
	that is pos2() - pos1()
Vector	dir () const
	that is ( pos2() - pos1() ).normalized()
Vector	center () const
	that is [ pos2() + pos1() ] / 2
PointExact	exact1 () const
	PointExact corresponding to first point.
PointExact	exact2 () const
	PointExact corresponding to second point.
bool	isFirst () const
	true if the segment is the first of the Fiber
bool	notFirst () const
	true if the segment is not the first of the Fiber
bool	isLast () const
	true if the segment is the last of the fiber
bool	notLast () const
	true if the segment is not the last of the fiber
void	projectPoint0 (Vector const &w, real &abs, real &dist) const
	calculate the projection of w on the line supporting the segment More...
void	projectPoint (Vector const &w, real &abs, real &dist) const
	calculate the projection of w on the line supporting the segment More...
void	projectPointF (const real[], real &abs, real &dist) const
	faster projectionPoint, but incompatible with periodic boundary conditions More...
int	intersectPlane (Vector const &n, real a, real &abs) const
	find the intersection with the plane defined by n.x + a = 0 More...
bool	projectSegment (FiberLocus const &that, real &a, real &b, real &dist) const
	calculates the closest distance between the two lines supporting the segments More...

Member Function Documentation

int intersectPlane	(	Vector const &	n,
		real	a,
		real &	abs
	)		const

Returns

0, +1 or -1:

• 0 if the segment does not interects the plane (in this case, abs is not set)
• +1 if the segment interect and fiber->dir().n > 0
• -1 if the segement intersects, and fiber->dir().n < 0

Intersection with the MINUS_END point is counted, but not with the PLUS_END point (return = 0).

void projectPoint	(	Vector const &	w,
		real &	abs,
		real &	dis
	)		const

W is projected on the line that supports this FiberLocus The function calculates:

• abs <- the signed distance from pos1() to the projection of W
• dist <- the distance between W and its projection

It is assumed here that len() returns the distance between the two points of the FiberLocus Attention: dis may not be set if ( abs < 0 ) or ( abs > len() )

void projectPoint0	(	Vector const &	w,
		real &	abs,
		real &	dis
	)		const

W is projected on the line that supports this FiberLocus The function calculates:

• abs <- the signed distance from pos1() to the projection of W
• dist <- the distance between W and its projection

It is assumed here that len() returns the distance between the two points of the FiberLocus Attention: dis is not set if ( abs < 0 ) or ( abs > len() )

void projectPointF	(	const real	w[],
		real &	abs,
		real &	dis
	)		const

This is a faster version of projectPoint(), but it does not work with periodic boundaries

bool projectSegment	(	FiberLocus const &	that,
		real &	abs1,
		real &	abs2,
		real &	dist
	)		const

Set dis to be the square of the minimum distance between the two lines. In 2D, the distance should be zero unless the two lines are parallel.

Abscissa abs1 and abs1 are set to indicate the points realizing this distance. The return value is true if both projections fall inside the segments.