Definition of an ellipse. More...

#include <Ellipse.h>

Public Member Functions
	Ellipse ()
	Basic constructor with default values. More...

	Ellipse (const Vector2 &center)
	Constructor with ellipse center definition. More...

	Ellipse (const Vector2 &center, const Vector2 &axes)
	Constructor with ellipse center definition and axes. More...

	Ellipse (const Vector2 &center, const Vector2 &axes, float angle)
	Constructor with ellipse center definition, axes, and orientation. More...

float	ellipseCenterDistance (const Ellipse &other) const
	Compute the distance between the centers of this ellipse and the provided ellipse. More...

Vector2	ellipseCenterDisplace (const Ellipse &other) const
	Computes the displacement from this ellipse's center to the other ellipse's center. More...

float	distanceOfClosestApproach (const Ellipse &other) const
	Compute the distance of closest approach between two ellipses. More...

float	approxDistanceOfClosestApproach (const Ellipse &other) const
	Compute the effective distance between this ellipse and the provided ellipse. More...

Vector2	closestPoint (const Vector2 &pt) const
	Computes the closest point on the ellipse to a point Also reports direction. More...

float	minimumDistance (const Agents::Obstacle *obstacle, Vector2 &dir) const
	Computes the minimum distance between the obstacle (a line segment) and the ellipse. More...

float	distanceOfClosestApproach (const Agents::Obstacle *line) const
	Computes the distance of closest approach. More...

float	approximateMinimumDistance (const Vector2 &pt) const
	Computes the approximate distance from point p to the ellipse. More...

float	radiusInPointDirection (const Vector2 &pt) const
	Computes the radius of the ellipse in the direction of the point. More...

Vector2	toEllipseSpace (const Vector2 &pt) const
	Translates the point into ellipse-space coordinates i.e. the transformation necessary to place the ellipse at the center, with its axes aligned with the world axes. More...

Vector2	fromEllipseSpace (const Vector2 &pt) const
	Translates the point from ellipse-space coordinates into world coordinates. More...

void	setOrientation (float angle)
	Sets the orientation of the ellipse. More...

void	setOrientation (const Vector2 &dir)
	Sets the orientation of the ellipse. More...

void	setCenter (const Vector2 &pos)
	Set center of the ellipse. More...

void	setAxes (const Vector2 &axes)
	Sets the major and minor axes of the ellipse. More...

void	setAxes (float major, float minor)
	Sets the major and minor axes of the ellipse. More...

void	setMajorAxis (float length)
	Sets the major axis of the ellipse. More...

float	getMajor () const
	Returns the length of the major axis. More...

void	setMinorAxis (float length)
	Sets the minor axis of the ellipse. More...

float	getMinor () const
	Returns the length of the minor axis. More...

float	getSmallerAxis () const
	Returns the smaller of the axes.

float	getLargerAxis () const
	Returns the larger of the axes.

Protected Attributes
Vector2	_center
	The center of the ellipse.

float	_cosPhi
	Part of the orientation of the ellipse. Oriented with angle phi. This is cosine of that angle.

float	_sinPhi
	Part of the orientation of the ellipse. Oriented with angle phi. This is sine of that angle.

float	_majorAxis
	Length of semi-major axis. The semi-major axis is the "direction" the ellipse is oriented. So, when phi is zero, the semi-major axis is aligned with the x-axis. It need not be a bigger value than the semi-minor axis.

float	_minorAxis
	Length of semi-minor axis. The semi-minor axis is perpendicular to the "direction" the ellipse is oriented. So, when phi is zero, the semi-minor axis is aligned with the y-axis. It need not be a smaller value than the semi-major axis.

Detailed Description

Definition of an ellipse.

Constructor & Destructor Documentation

GCF::Ellipse::Ellipse ( )

Basic constructor with default values.

By default, the Ellipse is a circle, centered on the origin.

GCF::Ellipse::Ellipse ( const Vector2 & center )

Constructor with ellipse center definition.

Parameters

center The position of the ellipse's center in R2.

GCF::Ellipse::Ellipse	(	const Vector2 &	center,
		const Vector2 &	axes
	)

Constructor with ellipse center definition and axes.

Parameters

center	The position of the ellipse's center in R2.
axes	The semi-major and semi-minor axis values stored in a two-dimensional vector.

GCF::Ellipse::Ellipse	(	const Vector2 &	center,
		const Vector2 &	axes,
		float	angle
	)

Constructor with ellipse center definition, axes, and orientation.

Parameters

center	The position of the ellipse's center in R2.
axes	The semi-major and semi-minor axis values stored in a two-dimensional vector.
angle	The angle (in radians) defining the orientation of the ellipse.

Member Function Documentation

float GCF::Ellipse::approxDistanceOfClosestApproach ( const Ellipse & other ) const

Compute the effective distance between this ellipse and the provided ellipse.

Effective distance is the distance between two ellipse boundaries along the line that connects the ellipse centers.

Parameters

other The other ellipse

Returns: The effective distance.

float GCF::Ellipse::approximateMinimumDistance ( const Vector2 & pt ) const

Computes the approximate distance from point p to the ellipse.

This is computed by finding the intersection of a line formed by the point and the origin with the ellipse. The distance is to that point. This is NOT the ACTUAL closest distance.

Parameters

pt	The point whose distance is to be computed.

Returns: A positive value if pt is outside the ellipse and a negative value if the point lies inside the ellipse.

Vector2 GCF::Ellipse::closestPoint ( const Vector2 & pt ) const

Computes the closest point on the ellipse to a point Also reports direction.

Parameters

pt	The point to which we want the closest point.

Returns: The point on the ellipse that was closest.

float GCF::Ellipse::distanceOfClosestApproach ( const Ellipse & other ) const

Compute the distance of closest approach between two ellipses.

Parameters

other The other ellipse

Returns: The distance of closest approach.

float GCF::Ellipse::distanceOfClosestApproach ( const Agents::Obstacle * line ) const

Computes the distance of closest approach.

It is the distance between the center and the line after the obstacle has been moved along its normal until it makes contact. The obstacle is interpreted as an INFINITE line

Parameters

line	The line segment obstacle to compute against.

Returns: float representing the "distance of closest approach"

Vector2 GCF::Ellipse::ellipseCenterDisplace ( const Ellipse & other ) const

inline

Computes the displacement from this ellipse's center to the other ellipse's center.

Parameters

other The other ellipse

Returns: The center displacement.

float GCF::Ellipse::ellipseCenterDistance ( const Ellipse & other ) const

inline

Compute the distance between the centers of this ellipse and the provided ellipse.

Parameters

other The other ellipse

Returns: The center distance.

Vector2 GCF::Ellipse::fromEllipseSpace ( const Vector2 & pt ) const

Translates the point from ellipse-space coordinates into world coordinates.

Parameters

pt	The point to translate.

Returns: The translated point.

float GCF::Ellipse::getMajor ( ) const

inline

Returns the length of the major axis.

Returns: The major axis

float GCF::Ellipse::getMinor ( ) const

inline

Returns the length of the minor axis.

Returns: The major axis

float GCF::Ellipse::minimumDistance	(	const Agents::Obstacle *	obstacle,
		Vector2 &	dir
	)		const

Computes the minimum distance between the obstacle (a line segment) and the ellipse.

Also provides the direction of that minimum displacement.

Parameters

obstacle	A pointer to the obstacle to test
dir	The direction of minimum displacment is set into this parameter.

Returns: The distance (in dir) from the nearest point on the obstacle to the ellipse.

float GCF::Ellipse::radiusInPointDirection ( const Vector2 & pt ) const

Computes the radius of the ellipse in the direction of the point.

Parameters

pt	The point used to define the direction. Should be different from the ellipse center and, ideally, outside the ellipse.

Returns: The length of the radius in this direction

void GCF::Ellipse::setAxes ( const Vector2 & axes )

inline

Sets the major and minor axes of the ellipse.

Parameters

axes	A two dimensional vector containg the major and minor axis sizes in the x and y values, respectively.

void GCF::Ellipse::setAxes	(	float	major,
		float	minor
	)

inline

Sets the major and minor axes of the ellipse.

Parameters

major	The value of the semi-major axis.
minor	The value of the semi-minor axis.

void GCF::Ellipse::setCenter ( const Vector2 & pos )

inline

Set center of the ellipse.

Parameters

pos	The two-dimensional vector specifying center position.

void GCF::Ellipse::setMajorAxis ( float length )

inline

Sets the major axis of the ellipse.

Parameters

length The value of the semi-major axis.

void GCF::Ellipse::setMinorAxis ( float length )

inline

Sets the minor axis of the ellipse.

Parameters

length The value of the semi-minor axis.

void GCF::Ellipse::setOrientation ( float angle )

inline

Sets the orientation of the ellipse.

Parameters

angle Rotation from x-axis in radians.

void GCF::Ellipse::setOrientation ( const Vector2 & dir )

inline

Sets the orientation of the ellipse.

Parameters

dir	A unit-length vector pointing in the direction

Vector2 GCF::Ellipse::toEllipseSpace ( const Vector2 & pt ) const

Translates the point into ellipse-space coordinates i.e. the transformation necessary to place the ellipse at the center, with its axes aligned with the world axes.

Parameters

pt	The point to translate.

Returns: The translated point.

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

PedPlugins/PedGCF/Ellipse.h
PedPlugins/PedGCF/Ellipse.cpp

Public Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation