gov.nasa.worldwind.geom
Class Cylinder

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

All Implemented Interfaces:

Extent, Renderable

public class Cylinder
extends Object
implements Extent, Renderable

Represents a geometric cylinder, most often used as a bounding volume. Cylinders are immutable.

Field Summary

protected Vec4	axisUnitDirection
protected Vec4	bottomCenter
protected double	cylinderHeight
protected double	cylinderRadius
protected Vec4	topCenter

Constructor Summary

Cylinder(Vec4 bottomCenter, Vec4 topCenter, double cylinderRadius)
Create a Cylinder from two points and a radius.

Cylinder(Vec4 bottomCenter, Vec4 topCenter, double cylinderRadius, Vec4 unitDirection)
Create a Cylinder from two points, a radius and an axis direction.

Method Summary

protected boolean	clipcyl(Vec4 raybase, Vec4 raycos, Vec4 bot, Vec4 top, Vec4 axis, double[] tVals)
static Cylinder	computeBoundingCylinder(Iterable<? extends Vec4> points) Compute a bounding cylinder for a collection of points.
static Cylinder	computeVerticalBoundingCylinder(Globe globe, double verticalExaggeration, Sector sector) Returns a cylinder that minimally surrounds the specified minimum and maximum elevations in the sector at a specified vertical exaggeration, and is oriented such that the cylinder axis is perpendicular to the globe's surface.
static Cylinder	computeVerticalBoundingCylinder(Globe globe, double verticalExaggeration, Sector sector, double minElevation, double maxElevation) Returns a cylinder that minimally surrounds the specified minimum and maximum elevations in the sector at a specified vertical exaggeration, and is oriented such that the cylinder axis is perpendicular to the globe's surface.
protected static Cylinder	computeVerticalBoundsFromSectorLatitudeRange(Globe globe, Sector sector, double minHeight, double maxHeight) Compute the Cylinder that surrounds the equator, and has height defined by the sector's minumum and maximum latitudes (including maxHeight).
protected static Cylinder	computeVerticalBoundsFromSectorQuadrilateral(Globe globe, Sector sector, double minHeight, double maxHeight) Returns a cylinder that minimally surrounds the specified height range in the sector.
protected static Cylinder	computeVerticalBoundsFromSectorVertices(Globe globe, Sector sector, double minHeight, double maxHeight) Returns a cylinder that surrounds the specified height range in the zero-area sector.
boolean	equals(Object o)
Vec4	getAxisUnitDirection() Returns the unit-length axis of this cylinder.
Vec4	getBottomCenter() Returns the this cylinder's bottom-center point.
Vec4	getCenter() Return this cylinder's center point.
double	getCylinderHeight() Returns this cylinder's height.
double	getCylinderRadius() Returns this cylinder's radius.
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.
Vec4	getTopCenter() Returns the this cylinder's top-center point.
double	getVolume() Return this cylinder's volume.
int	hashCode()
protected boolean	intcyl(Vec4 raybase, Vec4 raycos, Vec4 base, Vec4 axis, double radius, double[] tVals)
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.
protected double	intersects(Plane plane, double effectiveRadius)
protected double	intersectsAt(Plane plane, double effectiveRadius, Vec4[] endpoints)
void	render(DrawContext dc) Display the cylinder.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

axisUnitDirection

protected final Vec4 axisUnitDirection

bottomCenter

protected final Vec4 bottomCenter

cylinderHeight

protected final double cylinderHeight

cylinderRadius

protected final double cylinderRadius

topCenter

protected final Vec4 topCenter

Constructor Detail

Cylinder

public Cylinder(Vec4 bottomCenter,
                Vec4 topCenter,
                double cylinderRadius)

Create a Cylinder from two points and a radius.

Parameters:

bottomCenter - the center point of of the cylinder's base.

topCenter - the center point of the cylinders top.

cylinderRadius - the cylinder's radius.

Throws:

IllegalArgumentException - if the radius is zero or the top or bottom point is null or they are coincident.

Cylinder

public Cylinder(Vec4 bottomCenter,
                Vec4 topCenter,
                double cylinderRadius,
                Vec4 unitDirection)

Create a Cylinder from two points, a radius and an axis direction. Provided for use when unit axis is know and computation of it can be avoided.

Parameters:

bottomCenter - the center point of of the cylinder's base.

topCenter - the center point of the cylinders top.

cylinderRadius - the cylinder's radius.

unitDirection - the unit-length axis of the cylinder.

Throws:

IllegalArgumentException - if the radius is zero or the top or bottom point is null or they are coincident.

Method Detail

clipcyl

protected boolean clipcyl(Vec4 raybase,
                          Vec4 raycos,
                          Vec4 bot,
                          Vec4 top,
                          Vec4 axis,
                          double[] tVals)

computeBoundingCylinder

public static Cylinder computeBoundingCylinder(Iterable<? extends Vec4> points)

Compute a bounding cylinder for a collection of points.

Parameters:

points - the points to compute a bounding cylinder for.

Returns:

a cylinder bounding all the points. The axis of the cylinder is the longest principal axis of the collection. (See WWMath.computePrincipalAxes(Iterable).

Throws:

IllegalArgumentException - if the point list is null or empty.

See Also:

computeVerticalBoundingCylinder(gov.nasa.worldwind.globes.Globe, double, Sector)

computeVerticalBoundingCylinder

public static Cylinder computeVerticalBoundingCylinder(Globe globe,
                                                       double verticalExaggeration,
                                                       Sector sector)

Returns a cylinder that minimally surrounds the specified minimum and maximum elevations in the sector at a specified vertical exaggeration, and is oriented such that the cylinder axis is perpendicular to the globe's surface.

Parameters:

globe - The globe associated with the sector.

verticalExaggeration - the vertical exaggeration to apply to the minimum and maximum elevations when computing the cylinder.

sector - the sector to return the bounding cylinder for.

Returns:

The minimal bounding cylinder in Cartesian coordinates.

Throws:

IllegalArgumentException - if sector is null

See Also:

computeBoundingCylinder(Iterable)

computeVerticalBoundingCylinder

public static Cylinder computeVerticalBoundingCylinder(Globe globe,
                                                       double verticalExaggeration,
                                                       Sector sector,
                                                       double minElevation,
                                                       double maxElevation)

Returns a cylinder that minimally surrounds the specified minimum and maximum elevations in the sector at a specified vertical exaggeration, and is oriented such that the cylinder axis is perpendicular to the globe's surface.

Parameters:

globe - The globe associated with the sector.

verticalExaggeration - the vertical exaggeration to apply to the minimum and maximum elevations when computing the cylinder.

sector - the sector to return the bounding cylinder for.

minElevation - the minimum elevation of the bounding cylinder.

maxElevation - the maximum elevation of the bounding cylinder.

Returns:

The minimal bounding cylinder in Cartesian coordinates.

Throws:

IllegalArgumentException - if sector is null

See Also:

computeBoundingCylinder(Iterable)

computeVerticalBoundsFromSectorLatitudeRange

protected static Cylinder computeVerticalBoundsFromSectorLatitudeRange(Globe globe,
                                                                       Sector sector,
                                                                       double minHeight,
                                                                       double maxHeight)

Compute the Cylinder that surrounds the equator, and has height defined by the sector's minumum and maximum latitudes (including maxHeight).

Parameters:

globe - The globe associated with the sector.

sector - the sector to return the bounding cylinder for.

minHeight - the minimum height to include in the bounding cylinder.

maxHeight - the maximum height to include in the bounding cylinder.

Returns:

the minimal bounding cylinder in Cartesianl coordinates.

Throws:

IllegalArgumentException - if sector is null

computeVerticalBoundsFromSectorQuadrilateral

protected static Cylinder computeVerticalBoundsFromSectorQuadrilateral(Globe globe,
                                                                       Sector sector,
                                                                       double minHeight,
                                                                       double maxHeight)

Returns a cylinder that minimally surrounds the specified height range in the sector.

Parameters:

globe - The globe associated with the sector.

sector - the sector to return the bounding cylinder for.

minHeight - the minimum height to include in the bounding cylinder.

maxHeight - the maximum height to include in the bounding cylinder.

Returns:

The minimal bounding cylinder in Cartesian coordinates.

Throws:

IllegalArgumentException - if sector is null

computeVerticalBoundsFromSectorVertices

protected static Cylinder computeVerticalBoundsFromSectorVertices(Globe globe,
                                                                  Sector sector,
                                                                  double minHeight,
                                                                  double maxHeight)

Returns a cylinder that surrounds the specified height range in the zero-area sector. The returned cylinder won't be as tight a fit as computeBoundsFromSectorQuadrilateral.

Parameters:

globe - The globe associated with the sector.

sector - the sector to return the bounding cylinder for.

minHeight - the minimum height to include in the bounding cylinder.

maxHeight - the maximum height to include in the bounding cylinder.

Returns:

The minimal bounding cylinder in Cartesian coordinates.

Throws:

IllegalArgumentException - if sector is null

equals

public boolean equals(Object o)

Overrides:

equals in class Object

getAxisUnitDirection

public Vec4 getAxisUnitDirection()

Returns the unit-length axis of this cylinder.

Returns:

the unit-length axis of this cylinder.

getBottomCenter

public Vec4 getBottomCenter()

Returns the this cylinder's bottom-center point.

Returns:

this cylinder's bottom-center point.

getCenter

public Vec4 getCenter()

Return this cylinder's center point.

Specified by:

getCenter in interface Extent

Returns:

this cylinder's center point.

getCylinderHeight

public double getCylinderHeight()

Returns this cylinder's height.

Returns:

this cylinder's height.

getCylinderRadius

public double getCylinderRadius()

Returns this cylinder's radius.

Returns:

this cylinder's radius.

getDiameter

public 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.

Specified by:

getDiameter in interface Extent

Returns:

the extent's diameter.

getEffectiveRadius

public double getEffectiveRadius(Plane plane)

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

Specified by:

getEffectiveRadius in interface Extent

Parameters:

plane - the plane.

Returns:

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

getProjectedArea

public 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.

Specified by:

getProjectedArea in interface Extent

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.

getRadius

public 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.

Specified by:

getRadius in interface Extent

Returns:

the extent's radius.

getTopCenter

public Vec4 getTopCenter()

Returns the this cylinder's top-center point.

Returns:

this cylinder's top-center point.

getVolume

public double getVolume()

Return this cylinder's volume.

Returns:

this cylinder's volume.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

intcyl

protected boolean intcyl(Vec4 raybase,
                         Vec4 raycos,
                         Vec4 base,
                         Vec4 axis,
                         double radius,
                         double[] tVals)

intersect

public 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.

Specified by:

intersect in interface Extent

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

public 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.

Specified by:

intersects in interface Extent

Parameters:

frustum - the Frustum with which to test for intersection.

Returns:

true if there is an intersection, false otherwise.

intersects

public 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.

Specified by:

intersects in interface Extent

Parameters:

line - the Line with which to test for intersection.

Returns:

true if an intersection is found, false otherwise.

intersects

public boolean intersects(Plane plane)

Calculate whether or not this Extent is intersected by plane.

Specified by:

intersects in interface Extent

Parameters:

plane - the Plane with which to test for intersection.

Returns:

true if plane is found to intersect this Extent.

intersects

protected double intersects(Plane plane,
                            double effectiveRadius)

intersectsAt

protected double intersectsAt(Plane plane,
                              double effectiveRadius,
                              Vec4[] endpoints)

render

public void render(DrawContext dc)

Display the cylinder.

Specified by:

render in interface Renderable

Parameters:

dc - the current draw context.

Throws:

IllegalArgumentException - if the draw context is null.

See Also:

DrawContext

toString

public String toString()

Overrides:

toString in class Object