gov.nasa.worldwind.geom
Interface Extent

All Known Subinterfaces:

Globe

All Known Implementing Classes:

Box, Cylinder, Earth, EarthFlat, EllipsoidalGlobe, FlatGlobe, Sphere

public interface Extent

Represents a volume enclosing one or more objects or collections of points. Primarily used to test intersections with other objects.

Method Summary

Vec4	getCenter() Returns the extent's center point.
double	getDiameter() Returns the extent's diameter.
double	getEffectiveRadius(Plane plane) Computes the effective radius of the extent relative to a specified plane.
double	getProjectedArea(View view) Computes the area in square pixels of this Extent after it is projected into the specified view's viewport.
double	getRadius() Returns the extent's radius.
Intersection[]	intersect(Line line) Computes the intersections of this extent with line.
boolean	intersects(Frustum frustum) Determines whether or not this Extent intersects frustum.
boolean	intersects(Line line) Determines whether or not line intersects this Extent.
boolean	intersects(Plane plane) Calculate whether or not this Extent is intersected by plane.

Method Detail

getCenter

Vec4 getCenter()

Returns the extent's center point.

Returns:

the extent's center point.

getDiameter

double getDiameter()

Returns the extent's diameter. The computation of the diameter depends on the implementing class. See the documentation for the individual classes to determine how they compute a diameter.

Returns:

the extent's diameter.

getEffectiveRadius

double getEffectiveRadius(Plane plane)

Computes the effective radius of the extent relative to a specified plane.

Parameters:

plane - the plane.

Returns:

the effective radius, or 0 if the plane is null.

getProjectedArea

double getProjectedArea(View view)

Computes the area in square pixels of this Extent after it is projected into the specified view's viewport. The returned value is the screen area that this Extent covers in the infinite plane defined by the view's viewport. This area is not limited to the size of the view's viewport, and portions of this Extent are not clipped by the view's frustum.

This returns Double.POSITIVE_INFINITY if the view's eye point is inside this Extent, or if any portion of this Extent is behind the eye point. In either case, this Extent has no finite projection on the view.

Parameters:

view - the View for which to compute a projected screen area.

Returns:

the projected screen area of this Extent in square pixels, or Double.POSITIVE_INFINITY if the view's eye point is inside this Extent or part of this Extent is behind the view's eye point.

Throws:

IllegalArgumentException - if the view is null.

getRadius

double getRadius()

Returns the extent's radius. The computation of the radius depends on the implementing class. See the documentation for the individual classes to determine how they compute a radius.

Returns:

the extent's radius.

intersect

Intersection[] intersect(Line line)

Computes the intersections of this extent with line. The returned array may be either null or of zero length if no intersections are discovered. It does not contain null elements. Tangential intersections are marked as such. line is considered to have infinite length in both directions.

Parameters:

line - the Line with which to intersect this Extent.

Returns:

an array of intersections representing all the points where line enters or leave this Extent.

intersects

boolean intersects(Frustum frustum)

Determines whether or not this Extent intersects frustum. Returns true if any part of these two objects intersect, including the case where either object wholly contains the other, false otherwise.

Parameters:

frustum - the Frustum with which to test for intersection.

Returns:

true if there is an intersection, false otherwise.

intersects

boolean intersects(Line line)

Determines whether or not line intersects this Extent. This method may be faster than checking the size of the array returned by intersect(Line). Implementing methods must ensure that this method returns true if and only if intersect(Line) returns a non-null array containing at least one element.

Parameters:

line - the Line with which to test for intersection.

Returns:

true if an intersection is found, false otherwise.

intersects

boolean intersects(Plane plane)

Calculate whether or not this Extent is intersected by plane.

Parameters:

plane - the Plane with which to test for intersection.

Returns:

true if plane is found to intersect this Extent.