gov.nasa.worldwind.geom
Class Sphere

java.lang.Object
  gov.nasa.worldwind.geom.Sphere

All Implemented Interfaces:

Extent, Renderable

public final class Sphere
extends Object
implements Extent, Renderable

Represents a sphere in three dimensional space.

Instances of Sphere are immutable.

Field Summary

static Sphere

UNIT_SPHERE

Constructor Summary

Sphere(Vec4 center, double radius)
Creates a new Sphere from a given center and radius.

Method Summary

static Vec4[]	composeExtrema(Vec4[] points) Calculate the extrema of a given array of Vec4s.
static Sphere	createBoundingSphere(Vec4[] points) Creates a sphere that completely contains a set of points.
boolean	equals(Object o)
Vec4	getCenter() Obtains the center of this Sphere.
double	getDiameter() Obtains the diameter of this Sphere.
double	getRadius() Obtains the radius of this Sphere.
int	hashCode()
Intersection[]	intersect(Line line) Obtains the intersections of this sphere with a line.
boolean	intersects(Frustum frustum) tests for intersetion with a Frustum.
boolean	intersects(Line line) Tests for intersection with a Line.
boolean	intersects(Plane plane) Tests for intersection with a Plane.
void	render(DrawContext dc) Causes this Sphere to render itself using the DrawContext provided.
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

UNIT_SPHERE

public static final Sphere UNIT_SPHERE

Constructor Detail

Sphere

public Sphere(Vec4 center,
              double radius)

Creates a new Sphere from a given center and radius. radius must be positive (that is, greater than zero), and center may not be null.

Parameters:

center - the center of the new sphere

radius - the radius of the new sphere

Throws:

IllegalArgumentException - if center is null or if radius is non-positive

Method Detail

composeExtrema

public static Vec4[] composeExtrema(Vec4[] points)

Calculate the extrema of a given array of Vec4s. The resulting array is always of length 2, with the first element containing the minimum extremum, and the second containing the maximum. The minimum extremum is composed by taking the smallest x, y and z values from all the Vec4s in the array. These values are not necessarily taken from the same Vec4. The maximum extrema is composed in the same fashion.

Parameters:

points - any array of Vec4s

Returns:

a array with length of 2, comprising the most extreme values in the given array

Throws:

IllegalArgumentException - if points is null

createBoundingSphere

public static Sphere createBoundingSphere(Vec4[] points)

Creates a sphere that completely contains a set of points.

Parameters:

points - the Vec4s to be enclosed by the new Sphere

Returns:

a Sphere encompassing the given array of Vec4s

Throws:

IllegalArgumentException - if points is null or empty

equals

public boolean equals(Object o)

Overrides:

equals in class Object

getCenter

public final Vec4 getCenter()

Obtains the center of this Sphere.

Specified by:

getCenter in interface Extent

Returns:

the Vec4 situated at the center of this Sphere

getDiameter

public final double getDiameter()

Obtains the diameter of this Sphere. The diameter is twice the radius.

Specified by:

getDiameter in interface Extent

Returns:

the diameter of this Sphere

getRadius

public final double getRadius()

Obtains the radius of this Sphere. The radus is the distance from the center to the surface. If an object's distance to this sphere's center is less than or equal to the radius, then that object is at least partially within this Sphere.

Specified by:

getRadius in interface Extent

Returns:

the radius of this sphere

hashCode

public int hashCode()

Overrides:

hashCode in class Object

intersect

public final Intersection[] intersect(Line line)

Obtains the intersections of this sphere with a line. The returned array may be either null or of zero length if no intersections are discovered. It does not contain null elements and will have a size of 2 at most. Tangential intersections are marked as such. line is considered to have infinite length in both directions.

Specified by:

intersect in interface Extent

Parameters:

line - the Line with which to intersect this Sphere

Returns:

an array containing all the intersections of this Sphere and line

Throws:

IllegalArgumentException - if line is null

intersects

public boolean intersects(Frustum frustum)

tests for intersetion with a Frustum. This operation is commutative, so someSphere.intersects(frustum) and frustum.intersects(someSphere) are equivalent.

Specified by:

intersects in interface Extent

Parameters:

frustum - the Frustum with which to test for intersection

Returns:

true if either frustum or this Sphere wholly or partially contain the other, false otherwise.

Throws:

IllegalArgumentException - if frustum is null

intersects

public boolean intersects(Line line)

Tests for intersection with a Line.

Specified by:

intersects in interface Extent

Parameters:

line - the Line with which to test for intersection

Returns:

true if line intersects or makes a tangent with the surface of this Sphere

Throws:

IllegalArgumentException - if line is null

intersects

public boolean intersects(Plane plane)

Tests for intersection with a Plane.

Specified by:

intersects in interface Extent

Parameters:

plane - the Plane with which to test for intersection

Returns:

true if plane intersects or makes a tangent with the surface of this Sphere

Throws:

IllegalArgumentException - if plane is null

render

public void render(DrawContext dc)

Causes this Sphere to render itself using the DrawContext provided. dc may not be null.

Specified by:

render in interface Renderable

Parameters:

dc - the DrawContext to be used

Throws:

IllegalArgumentException - if dc is null

See Also:

DrawContext

toString

public String toString()

Overrides:

toString in class Object