gov.nasa.worldwind.geom
Class Frustum

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

Direct Known Subclasses:

PickPointFrustum

public class Frustum
extends Object

Represents a view frustum composed of six planes: left, right, bottom, top, near far.

Frustum instances are immutable.

Nested Class Summary

static class

Frustum.Corners Holds the eight corner points of a frustum.

Field Summary

protected Plane[]	allPlanes Holds all six frustum planes in an array in the order left, right, bottom, top, near, far.
protected Plane	bottom
protected Plane	far
protected Plane	left
protected Plane	near
protected Plane	right
protected Plane	top

Constructor Summary

Frustum()
Constructs a frustum two meters wide centered at the origin.

Frustum(Plane left, Plane right, Plane bottom, Plane top, Plane near, Plane far)
Create a frustum from six Planes defining the frustum boundaries.

Method Summary

boolean	contains(Extent extent) Indicates whether a specified Extent is fully within this frustum.
boolean	contains(Vec4 point) Indicates whether a specified point is within this frustum.
boolean	equals(Object obj)
static Frustum	fromPerspective(Angle horizontalFieldOfView, int viewportWidth, int viewportHeight, double near, double far) Creates a Frustum from a horizontal field-of-view, viewport aspect ratio and distance to near and far depth clipping planes.
static Frustum	fromPerspective(double width, double height, double near, double far) Creates a Frustum from three sets of parallel clipping planes (a parallel projectionMatrix).
static Frustum	fromPerspectiveVecs(Vec4 vTL, Vec4 vTR, Vec4 vBL, Vec4 vBR, double near, double far) Creates a Frustum from four edge vectors, viewport aspect ratio and distance to near and far planes.
static Frustum	fromProjectionMatrix(Matrix projectionMatrix) Creates a frustum by extracting the six frustum planes from a projection matrix.
Plane[]	getAllPlanes() Returns all the planes.
Plane	getBottom() Returns the bottom plane.
Frustum.Corners	getCorners() Returns the eight corners of this frustum.
Plane	getFar() Returns the far plane.
Plane	getLeft() Returns the left plane.
Plane	getNear() Returns the near plane.
Plane	getRight() Returns the right plane.
Plane	getTop() Returns the top plane.
int	hashCode()
boolean	intersects(Extent extent) Indicates whether a specified Extent intersects this frustum.
boolean	intersectsSegment(Vec4 pa, Vec4 pb) Determines whether a line segment intersects this frustum.
String	toString()
Frustum	transformBy(Matrix matrix) Returns a copy of this frustum transformed by a specified Matrix.

Methods inherited from class java.lang.Object

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

Field Detail

allPlanes

protected final Plane[] allPlanes

Holds all six frustum planes in an array in the order left, right, bottom, top, near, far.

bottom

protected final Plane bottom

far

protected final Plane far

left

protected final Plane left

near

protected final Plane near

right

protected final Plane right

top

protected final Plane top

Constructor Detail

Frustum

public Frustum()

Constructs a frustum two meters wide centered at the origin. Primarily used for testing.

Frustum

public Frustum(Plane left,
               Plane right,
               Plane bottom,
               Plane top,
               Plane near,
               Plane far)

Create a frustum from six Planes defining the frustum boundaries.

None of the arguments may be null.

Parameters:

near - the near plane

far - the far plane

left - the left plane

right - the right plane

top - the top plane

bottom - the bottom plane

Throws:

IllegalArgumentException - if any argument is null.

Method Detail

contains

public final boolean contains(Extent extent)

Indicates whether a specified Extent is fully within this frustum.

Parameters:

extent - the Extent to test.

Returns:

true if the extent is fully within this frustum, otherwise false.

Throws:

IllegalArgumentException - if the extent is null.

contains

public final boolean contains(Vec4 point)

Indicates whether a specified point is within this frustum.

Parameters:

point - the point to test.

Returns:

true if the point is within the frustum, otherwise false.

Throws:

IllegalArgumentException - if the point is null.

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

fromPerspective

public static Frustum fromPerspective(Angle horizontalFieldOfView,
                                      int viewportWidth,
                                      int viewportHeight,
                                      double near,
                                      double far)

Creates a Frustum from a horizontal field-of-view, viewport aspect ratio and distance to near and far depth clipping planes. The near plane must be closer than the far plane, and both near and far values must be positive.

Parameters:

horizontalFieldOfView - horizontal field-of-view angle in the range (0, 180)

viewportWidth - the width of the viewport in screen pixels

viewportHeight - the height of the viewport in screen pixels

near - distance to the near depth clipping plane

far - distance to far depth clipping plane

Returns:

Frustum configured from the specified perspective parameters.

Throws:

IllegalArgumentException - if fov is not in the range (0, 180), if either near or far are negative, or near is greater than or equal to far

fromPerspective

public static Frustum fromPerspective(double width,
                                      double height,
                                      double near,
                                      double far)

Creates a Frustum from three sets of parallel clipping planes (a parallel projectionMatrix). In this case, the near and far depth clipping planes may be negative.

Parameters:

near - distance to the near depth clipping plane

far - distance to far depth clipping plane

width - horizontal dimension of the near clipping plane

height - vertical dimension of the near clipping plane

Returns:

a Frustum configured with the specified perspective parameters.

Throws:

IllegalArgumentException - if the difference of any plane set (lright - left, top - bottom, far - near) is less than or equal to zero.

fromPerspectiveVecs

public static Frustum fromPerspectiveVecs(Vec4 vTL,
                                          Vec4 vTR,
                                          Vec4 vBL,
                                          Vec4 vBR,
                                          double near,
                                          double far)

Creates a Frustum from four edge vectors, viewport aspect ratio and distance to near and far planes. The edge vectors connect the near corners of the frustum to the far corners. The near plane must be closer than the far plane, and both planes must be positive.

Parameters:

vTL - vector defining the top-left of the frustum

vTR - vector defining the top-right of the frustum

vBL - vector defining the bottom-left of the frustum

vBR - vector defining the bottom-right of the frustum

near - distance to the near plane

far - distance to far plane

Returns:

Frustum that was created

Throws:

IllegalArgumentException - if any of the vectors are null, if either near or far are negative, or near is greater than or equal to far

fromProjectionMatrix

public static Frustum fromProjectionMatrix(Matrix projectionMatrix)

Creates a frustum by extracting the six frustum planes from a projection matrix.

Parameters:

projectionMatrix - the projection matrix to extract the frustum planes from.

Returns:

a frustum defined by the extracted planes.

Throws:

IllegalArgumentException - if the projection matrix is null.

getAllPlanes

public Plane[] getAllPlanes()

Returns all the planes.

Returns:

an array of the frustum planes, in the order left, right, bottom, top, near, far.

getBottom

public final Plane getBottom()

Returns the bottom plane.

Returns:

the bottom plane.

getCorners

public Frustum.Corners getCorners()

Returns the eight corners of this frustum.

Returns:

the eight frustum corners.

getFar

public final Plane getFar()

Returns the far plane.

Returns:

the left plane.

getLeft

public final Plane getLeft()

Returns the left plane.

Returns:

the left plane.

getNear

public final Plane getNear()

Returns the near plane.

Returns:

the left plane.

getRight

public final Plane getRight()

Returns the right plane.

Returns:

the right plane.

getTop

public final Plane getTop()

Returns the top plane.

Returns:

the top plane.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

intersects

public boolean intersects(Extent extent)

Indicates whether a specified Extent intersects this frustum.

Parameters:

extent - the Extent to test.

Returns:

true if the extent intersects this frustum, otherwise false.

Throws:

IllegalArgumentException - if the extent is null.

intersectsSegment

public boolean intersectsSegment(Vec4 pa,
                                 Vec4 pb)

Determines whether a line segment intersects this frustum.

Parameters:

pa - one end of the segment.

pb - the other end of the segment.

Returns:

true if the segment intersects or is contained in the frustum, otherwise false.

Throws:

IllegalArgumentException - if either point is null.

toString

public String toString()

Overrides:

toString in class Object

transformBy

public Frustum transformBy(Matrix matrix)

Returns a copy of this frustum transformed by a specified Matrix.

Parameters:

matrix - the Matrix to apply to this frustum.

Returns:

a new frustum transformed by the specified matrix.

Throws:

IllegalArgumentException - if the matrix is null.