gov.nasa.worldwind.shape

Class OmnidirectionalSightline

java.lang.Object

gov.nasa.worldwind.render.AbstractRenderable

gov.nasa.worldwind.shape.OmnidirectionalSightline

All Implemented Interfaces:

Renderable, Attributable, Highlightable, Movable

public class OmnidirectionalSightline
extends AbstractRenderable
implements Attributable, Highlightable, Movable

Displays an omnidirectional sightline's visibility within the WorldWind scene. The sightline's placement and area of potential visibility are represented by a Cartesian sphere with a center position and a range. Terrain features within the sphere are considered visible if there is a direct line-of-sight between the center position and a given terrain point.

OmnidirectionalSightline displays an overlay on the WorldWind terrain indicating which terrain features are visible, and which are occluded. Visible terrain features, those having a direct line-of-sight to the center position, appear in the sightline's normal attributes or its highlight attributes, depending on the highlight state. Occluded terrain features appear in the sightline's occlude attributes, regardless of highlight state. Terrain features outside the sightline's range are excluded from the overlay.

Limitations and Planned Improvements

• OmnidirectionalSightline is currently limited to terrain-based occlusion, and does not incorporate other 3D scene elements during visibility determination. Subsequent iterations will support occlusion of both terrain and 3D polygons.
• The visibility overlay is drawn in ShapeAttributes' interior color only. Subsequent iterations will add an outline where the sightline's range intersects the scene, and will display the sightline's geometry as an outline.
• OmnidirectionalSightline requires OpenGL ES 2.0 extension GL_OES_depth_texture. Subsequent iterations may relax this requirement.

Constructor Summary

Constructors

Constructor and Description
OmnidirectionalSightline(Position position, double range) Constructs an OmnidirectionalSightline that displays the line-of-sight from a specified center position and range.
OmnidirectionalSightline(Position position, double range, ShapeAttributes attributes) Constructs an OmnidirectionalSightline that displays the line-of-sight from a specified center position and range.

Method Summary

Modifier and Type	Method and Description
int	getAltitudeMode() Indicates the altitude mode associated with this sightline's position.
ShapeAttributes	getAttributes() Indicates this sightline's "normal" attributes.
ShapeAttributes	getHighlightAttributes() Indicates this sightline's "highlight" attributes.
ShapeAttributes	getOccludeAttributes() Indicates this sightline's "occlude" attributes.
Position	getPosition() Indicates the geographic position where this sightline is centered.
double	getRange() Indicates this sightline's range.
Position	getReferencePosition() A position associated with the object that indicates its aggregate geographic position.
boolean	isHighlighted() Indicates whether this sightline's overlay uses its highlight attributes rather than its normal attributes for visible features.
void	moveTo(Globe globe, Position position) Moves the sightline over the globe's surface.
OmnidirectionalSightline	setAltitudeMode(int altitudeMode) Sets the altitude mode associated with this sightline's position.
void	setAttributes(ShapeAttributes attributes) Sets this sightline's "normal" attributes to the supplied attributes bundle.
void	setHighlightAttributes(ShapeAttributes highlightAttributes) Sets this sightline's "highlight" attributes.
void	setHighlighted(boolean highlighted) Sets the highlighted state of this sightline, which indicates whether this sightline's overlay uses its highlight attributes rather than its normal attributes for visible features.
void	setOccludeAttributes(ShapeAttributes occludeAttributes) Sets this sightline's "occlude" attributes.
OmnidirectionalSightline	setPosition(Position position) Sets this sightline's geographic position to the values in the supplied position.
OmnidirectionalSightline	setRange(double meters) Sets this sightline's range.

Methods inherited from class gov.nasa.worldwind.render.AbstractRenderable

getDisplayName, getPickDelegate, getUserProperty, hasUserProperty, isEnabled, putUserProperty, removeUserProperty, render, setDisplayName, setEnabled, setPickDelegate

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

OmnidirectionalSightline

public OmnidirectionalSightline(Position position,
                                double range)

Constructs an OmnidirectionalSightline that displays the line-of-sight from a specified center position and range. Visible features are displayed in white, while occluded features are displayed in red.

Parameters:

position - the position where the sightline is centered

range - the sightline's range in meters from its position

Throws:

java.lang.IllegalArgumentException - If the position is null, or if the range is negative

OmnidirectionalSightline

public OmnidirectionalSightline(Position position,
                                double range,
                                ShapeAttributes attributes)

Constructs an OmnidirectionalSightline that displays the line-of-sight from a specified center position and range. Visible features are displayed in the specified attributes, while occluded features are displayed in red.

Parameters:

position - the position where the sightline is centered

range - the sightline's range in meters from its position

attributes - a reference to an attributes bundle used by this sightline when not highlighted

Throws:

java.lang.IllegalArgumentException - If the position is null, or if the range is negative

Method Detail

getPosition

public Position getPosition()

Indicates the geographic position where this sightline is centered.

Returns:

this sightline's geographic position

setPosition

public OmnidirectionalSightline setPosition(Position position)

Sets this sightline's geographic position to the values in the supplied position.

Parameters:

position - the new position where this sightline is centered

Returns:

this sightline, with its position set to the specified value

Throws:

java.lang.IllegalArgumentException - If the position is null

getAltitudeMode

public int getAltitudeMode()

Indicates the altitude mode associated with this sightline's position.

Returns:

the altitude mode, see WorldWind.AltitudeMode for possible

setAltitudeMode

public OmnidirectionalSightline setAltitudeMode(int altitudeMode)

Sets the altitude mode associated with this sightline's position.

Parameters:

altitudeMode - the new altitude mode, see WorldWind.AltitudeMode for acceptable values

Returns:

this sightline with its altitude mode set to the specified value

getRange

public double getRange()

Indicates this sightline's range. Range represents the sightline's transmission distance in meters from its center position.

Returns:

this sightline's range in meters.

setRange

public OmnidirectionalSightline setRange(double meters)

Sets this sightline's range. Range represents the sightline's transmission distance in meters from its center position.

Parameters:

meters - this sightline's range in meters

Returns:

this sightline with its range set to the specified value

Throws:

java.lang.IllegalArgumentException - If the range is negative

getAttributes

public ShapeAttributes getAttributes()

Indicates this sightline's "normal" attributes. These attributes are used for the sightline's overlay when the highlighted flag is false, and there is a direct line-of-sight from the sightline's center position to a terrain feature. If null and this sightline is not highlighted, visible terrain features are excluded from the overlay.

Specified by:

getAttributes in interface Attributable

Returns:

a reference to this sightline's attributes bundle

setAttributes

public void setAttributes(ShapeAttributes attributes)

Sets this sightline's "normal" attributes to the supplied attributes bundle. These attributes are used for the sightline's overlay when the highlighted flag is false, and there is a direct line-of-sight from the sightline's center position to a terrain feature. If null and this sightline is not highlighted, visible terrain features are excluded from the overlay.

It is permissible to share attribute bundles between sightlines.

Specified by:

setAttributes in interface Attributable

Parameters:

attributes - a reference to an attributes bundle used by this sightline when not highlighted

getHighlightAttributes

public ShapeAttributes getHighlightAttributes()

Indicates this sightline's "highlight" attributes. These attributes are used for the sightline's overlay when the highlighted flag is true, and there is a direct line-of-sight from the sightline's center position to a terrain feature. If null and the highlighted flag is true, this sightline's normal attributes are used. If they, too, are null, visible terrain features are excluded from the overlay.

Specified by:

getHighlightAttributes in interface Attributable

Returns:

a reference to this sightline's highlight attributes bundle

setHighlightAttributes

public void setHighlightAttributes(ShapeAttributes highlightAttributes)

Sets this sightline's "highlight" attributes. These attributes are used for the sightline's overlay when the highlighted flag is true, and there is a direct line-of-sight from the sightline's center position to a terrain feature. If null and the highlighted flag is true, this sightline's normal attributes are used. If they, too, are null, visible terrain features are excluded from the overlay.

It is permissible to share attribute bundles between sightlines.

Specified by:

setHighlightAttributes in interface Attributable

Parameters:

highlightAttributes - a reference to the attributes bundle used by this sightline when highlighted

getOccludeAttributes

public ShapeAttributes getOccludeAttributes()

Indicates this sightline's "occlude" attributes. These attributes are used for the sightline's overlay when there's no direct line-of-sight from the sightline's center position to a terrain feature. If null, occluded terrain features are excluded from the overlay.

Returns:

a reference to this sightline's occlude attributes bundle

setOccludeAttributes

public void setOccludeAttributes(ShapeAttributes occludeAttributes)

Sets this sightline's "occlude" attributes. These attributes are used for the sightline's overlay when there's no direct line-of-sight from the sightline's center position to a terrain feature. If null, occluded terrain features are excluded from the overlay.

It is permissible to share attribute bundles between sightlines.

Parameters:

occludeAttributes - a reference to an attributes bundle used by this sightline when occluded

isHighlighted

public boolean isHighlighted()

Indicates whether this sightline's overlay uses its highlight attributes rather than its normal attributes for visible features.

Specified by:

isHighlighted in interface Highlightable

Returns:

true if this sightline is highlighted, and false otherwise

setHighlighted

public void setHighlighted(boolean highlighted)

Sets the highlighted state of this sightline, which indicates whether this sightline's overlay uses its highlight attributes rather than its normal attributes for visible features.

Specified by:

setHighlighted in interface Highlightable

Parameters:

highlighted - true to highlight this sightline, and false otherwise

getReferencePosition

public Position getReferencePosition()

A position associated with the object that indicates its aggregate geographic position. For an OmnidirectionalSightline, this is simply it's position property.

Specified by:

getReferencePosition in interface Movable

Returns:

getPosition()

moveTo

public void moveTo(Globe globe,
                   Position position)

Moves the sightline over the globe's surface. For an OmnidirectionalSightline, this simply calls setPosition(Position).

Specified by:

moveTo in interface Movable

Parameters:

globe - not used.

position - the new position of the sightline's reference position.