gov.nasa.worldwind.geom

Class Line

java.lang.Object

gov.nasa.worldwind.geom.Line

public class Line
extends java.lang.Object

Represents a line in Cartesian coordinates.

Field Summary

Fields

Modifier and Type	Field and Description
Vec3	direction This line's direction.
Vec3	origin This line's origin.

Constructor Summary

Constructors

Constructor and Description
Line() Constructs a line with origin and direction both zero.
Line(Line line) Constructs a line with the origin and direction from a specified line.
Line(Vec3 origin, Vec3 direction) Constructs a line with a specified origin and direction.

Method Summary

Modifier and Type	Method and Description
boolean	equals(java.lang.Object o)
int	hashCode()
Vec3	pointAt(double distance, Vec3 result) Computes a Cartesian point a specified distance along this line.
Line	set(Vec3 origin, Vec3 direction) Sets this line to a specified origin and direction.
Line	setToSegment(Vec3 pointA, Vec3 pointB) Sets this line to the specified segment.
java.lang.String	toString()
boolean	triStripIntersection(float[] points, int stride, short[] elements, int count, Vec3 result) Computes the first intersection of a triangle strip with this line.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Field Detail

origin

public final Vec3 origin

This line's origin.

direction

public final Vec3 direction

This line's direction.

Constructor Detail

Line

public Line()

Constructs a line with origin and direction both zero.

Line

public Line(Vec3 origin,
            Vec3 direction)

Constructs a line with a specified origin and direction.

Parameters:

origin - the line's origin

direction - the line's direction

Throws:

java.lang.IllegalArgumentException - If either the origin or the direction are null

Line

public Line(Line line)

Constructs a line with the origin and direction from a specified line.

Parameters:

line - the line specifying origin and direction

Throws:

java.lang.IllegalArgumentException - If the line is null

Method Detail

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

set

public Line set(Vec3 origin,
                Vec3 direction)

Sets this line to a specified origin and direction.

Parameters:

origin - the line's new origin

direction - the line's new direction

Returns:

this line, set to the new origin and direction

Throws:

java.lang.IllegalArgumentException - If either the origin or the direction are null

setToSegment

public Line setToSegment(Vec3 pointA,
                         Vec3 pointB)

Sets this line to the specified segment. This line has its origin at the first endpoint and its direction extending from the first endpoint to the second.

Parameters:

pointA - the segment's first endpoint

pointB - the segment's second endpoint

Returns:

this line, set to the specified segment

Throws:

java.lang.IllegalArgumentException - If either endpoint is null

pointAt

public Vec3 pointAt(double distance,
                    Vec3 result)

Computes a Cartesian point a specified distance along this line.

Parameters:

distance - The distance from this line's origin at which to compute the point.

result - A pre-allocated Vec3 instance in which to return the computed point.

Returns:

The specified result argument containing the computed point.

Throws:

java.lang.IllegalArgumentException - If the specified result argument is null or undefined.

triStripIntersection

public boolean triStripIntersection(float[] points,
                                    int stride,
                                    short[] elements,
                                    int count,
                                    Vec3 result)

Computes the first intersection of a triangle strip with this line. This line is interpreted as a ray; intersection points behind the line's origin are ignored.

The triangle strip is specified by a list of vertex points and a list of elements indicating the triangle strip tessellation of those vertices. The triangle strip elements are interpreted in the same manner as OpenGL, where each index indicates a vertex position rather than an actual index into the points array (e.g. a triangle strip index of 1 indicates the XYZ tuple starting at array index 3).

Parameters:

points - an array of points containing XYZ tuples

stride - the number of coordinates between the first coordinate of adjacent points - must be at least 3

elements - an array of indices into the points defining the triangle strip organization

count - the number of indices to consider

result - a pre-allocated Vec3 in which to return the nearest intersection point, if any

Returns:

true if this line intersects the triangle strip, otherwise false

Throws:

java.lang.IllegalArgumentException - If either array is null or empty, if the stride is less than 3, if the count is less than 0, or if the result argument is null