Module org.dyn4j

Package org.dyn4j.geometry

Class Circle

Object

AbstractShape

Circle

All Implemented Interfaces:

DataContainer, Convex, Rotatable, Shape, Transformable, Translatable

public class Circle
extends AbstractShape
implements Convex, Shape, Transformable, DataContainer

Implementation of a Circle Convex Shape.

A Circle's radius must be greater than zero.

Since:

1.0.0

Version:

3.2.0

Author:

William Bittle

Constructor Summary

Constructors

Constructor	Description
Circle(double radius)	Full constructor.

Method Summary

Modifier and Type	Method	Description
void	computeAABB(Transform transform, AABB aabb)	Computes the AABB from this Shape after applying the given transformation and places the result in the given AABB.
boolean	contains(Vector2 point, Transform transform)	Returns true if the given point is inside this Shape.
Mass	createMass(double density)	Creates a Mass object using the geometric properties of this Shape and the given density.
Vector2[]	getAxes(Vector2[] foci, Transform transform)	Returns an array of separating axes to test for this Shape.
PointFeature	getFarthestFeature(Vector2 vector, Transform transform)	Returns the Feature farthest in the direction of the given vector.
Vector2	getFarthestPoint(Vector2 vector, Transform transform)	Returns the point farthest in the direction of the given vector.
Vector2[]	getFoci(Transform transform)	Returns an array of world space foci points for circular curved edges.
double	getRadius(Vector2 center)	Returns the radius of the shape if the given point was the center for this shape.
Interval	project(Vector2 vector, Transform transform)	Returns the Interval of this Shape projected onto the given Vector2 given the Transform.
String	toString()

Methods inherited from class AbstractShape

computeAABB, contains, createAABB, createAABB, getCenter, getRadius, getUserData, project, rotate, rotate, rotate, rotate, rotate, rotate, rotateAboutCenter, setUserData, translate, translate

Methods inherited from class Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface DataContainer

getUserData, setUserData

Methods inherited from interface Rotatable

rotate, rotate, rotate, rotate, rotate, rotate

Methods inherited from interface Shape

computeAABB, contains, createAABB, createAABB, getCenter, getRadius, project, rotateAboutCenter

Methods inherited from interface Translatable

translate, translate

Constructor Detail

Circle

public Circle(double radius)

Full constructor.

Creates a new Circle centered on the origin with the given radius.

Parameters:

radius - the radius

Throws:

IllegalArgumentException - if the given radius is less than or equal to zero

Method Detail

getRadius

public double getRadius(Vector2 center)

Description copied from interface: Shape

Returns the radius of the shape if the given point was the center for this shape.

Specified by:

getRadius in interface Shape

Parameters:

center - the center point

Returns:

double

toString

public String toString()

Overrides:

toString in class AbstractShape

contains

public boolean contains(Vector2 point,
                        Transform transform)

Description copied from interface: Shape

Returns true if the given point is inside this Shape.

If the given point lies on an edge the point is considered to be inside the Shape.

The given point is assumed to be in world space.

Specified by:

contains in interface Shape

Parameters:

point - world space point

transform - Transform for this Shape

Returns:

boolean

project

public Interval project(Vector2 vector,
                        Transform transform)

Description copied from interface: Shape

Returns the Interval of this Shape projected onto the given Vector2 given the Transform.

Specified by:

project in interface Shape

Parameters:

vector - Vector2 to project onto

transform - Transform for this Shape

Returns:

Interval

getFarthestFeature

public PointFeature getFarthestFeature(Vector2 vector,
                                       Transform transform)

Returns the Feature farthest in the direction of the given vector.

The returned feature is in world space.

For a Circle this will always return a PointFeature.

Specified by:

getFarthestFeature in interface Convex

Parameters:

vector - the direction

transform - the local to world space Transform of this Convex Shape

Returns:

Feature

getFarthestPoint

public Vector2 getFarthestPoint(Vector2 vector,
                                Transform transform)

Description copied from interface: Convex

Returns the point farthest in the direction of the given vector. If two points are equally distant along the given Vector2 the first one is used.

The returned point is in world space.

Specified by:

getFarthestPoint in interface Convex

Parameters:

vector - the direction

transform - the local to world space Transform of this Convex Shape

Returns:

Vector2

getAxes

public Vector2[] getAxes(Vector2[] foci,
                         Transform transform)

Returns an array of separating axes to test for this Shape.

The foci parameter is an array of circular focal points of the other Shape.

If foci points are given, this method will return the separating axes for this Shape's voronoi regions also. The points in the foci array are assumed to be in world space.

The returned axes are normalized and in world space.

Circular shapes are handled specifically in the SAT algorithm since they have an infinite number of axes. As a result this method returns null.

Specified by:

getAxes in interface Convex

Parameters:

foci - the world space points representing foci of curved Shapes; can be null

transform - the local to world space Transform of this Convex Shape

Returns:

null

getFoci

public Vector2[] getFoci(Transform transform)

Description copied from interface: Convex

Returns an array of world space foci points for circular curved edges.

This method returns null if the Shape has zero curved edges.

The returned points are in world space.

Specified by:

getFoci in interface Convex

Parameters:

transform - the local to world space Transform of this Convex Shape

Returns:

Vector2[]

createMass

public Mass createMass(double density)

Creates a Mass object using the geometric properties of this Shape and the given density.

m = d * π * r² I = m * r² / 2

Specified by:

createMass in interface Shape

Parameters:

density - the density in kg/m²

Returns:

Mass the Mass of this Shape

computeAABB

public void computeAABB(Transform transform,
                        AABB aabb)

Description copied from interface: Shape

Computes the AABB from this Shape after applying the given transformation and places the result in the given AABB.

Specified by:

computeAABB in interface Shape

Parameters:

transform - the Transform for this Shape

aabb - the destination AABB