org.cesiumjs.cs.core

Class Occluder

java.lang.Object

org.cesiumjs.cs.core.Occluder

@JsType(isNative=true,
        namespace="Cesium",
        name="Occluder")
public class Occluder
extends Object

Author:

Serge Silaev aka iSergio

Field Summary

Fields

Modifier and Type	Field and Description
Cartesian3	cameraPosition The position of the camera.
Cartesian3	position The position of the occluder.
double	radius The radius of the occluder.

Constructor Summary

Constructors

Constructor and Description
Occluder(BoundingSphere occluderBoundingSphere, Cartesian3 cameraPosition) Creates an Occluder derived from an object's position and radius, as well as the camera position.

Method Summary

Modifier and Type	Method and Description
static Object	computeOccludeePoint(BoundingSphere occluderBoundingSphere, Cartesian3 occludeePosition, Cartesian3[] positions) Computes a point that can be used as the occludee position to the visibility functions.
static Object	computeOccludeePointFromRectangle(Rectangle rectangle) Computes a point that can be used as the occludee position to the visibility functions from an rectangle.
static Object	computeOccludeePointFromRectangle(Rectangle rectangle, Ellipsoid ellipsoid) Computes a point that can be used as the occludee position to the visibility functions from an rectangle.
Number	computeVisibility(BoundingSphere occludeeBS) Determine to what extent an occludee is visible (not visible, partially visible, or fully visible).
static Occluder	fromBoundingSphere(BoundingSphere occluderBoundingSphere, Cartesian3 cameraPosition) Creates an occluder from a bounding sphere and the camera position.
static Occluder	fromBoundingSphere(BoundingSphere occluderBoundingSphere, Cartesian3 cameraPosition, Occluder result) Creates an occluder from a bounding sphere and the camera position.
boolean	isBoundingSphereVisible(BoundingSphere occludee) Determines whether or not a sphere, the occludee, is hidden from view by the occluder.
boolean	isPointVisible(Cartesian3 occludee) etermines whether or not a point, the occludee, is hidden from view by the occluder.

Methods inherited from class java.lang.Object

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

Field Detail

cameraPosition

@JsProperty
public Cartesian3 cameraPosition

The position of the camera.

position

@JsProperty
public Cartesian3 position

The position of the occluder.

radius

@JsProperty
public double radius

The radius of the occluder.

Constructor Detail

Occluder

@JsConstructor
public Occluder(BoundingSphere occluderBoundingSphere,
                               Cartesian3 cameraPosition)

Creates an Occluder derived from an object's position and radius, as well as the camera position. The occluder can be used to determine whether or not other objects are visible or hidden behind the visible horizon defined by the occluder and camera position.

     Example:
     
     // Construct an occluder one unit away from the origin with a radius of one.
     Cartesian3 cameraPosition = Cartesian3.ZERO();
     BoundingSphere occluderBoundingSphere = new BoundingSphere(new Cartesian3(0, 0, -1), 1);
     Occluder occluder = new Occluder(occluderBoundingSphere, cameraPosition);
     
 

Parameters:

occluderBoundingSphere - The bounding sphere surrounding the occluder.

cameraPosition - The coordinate of the viewer/camera.

Method Detail

computeOccludeePoint

@JsMethod
public static Object computeOccludeePoint(BoundingSphere occluderBoundingSphere,
                                                    Cartesian3 occludeePosition,
                                                    Cartesian3[] positions)

Computes a point that can be used as the occludee position to the visibility functions. Use a radius of zero for the occludee radius. Typically, a user computes a bounding sphere around an object that is used for visibility; however it is also possible to compute a point that if seen/not seen would also indicate if an object is visible/not visible. This function is better called for objects that do not move relative to the occluder and is large, such as a chunk of terrain. You are better off not calling this and using the object's bounding sphere for objects such as a satellite or ground vehicle.

     
     Cartesian3 cameraPosition = new Cartesian3(0, 0, 0);
     BoundingSphere occluderBoundingSphere = new BoundingSphere(new Cartesian3(0, 0, -8), 2);
     Occluder occluder = new Occluder(occluderBoundingSphere, cameraPosition);
     Cartesian3[] positions = {new Cartesian3(-0.25, 0, -5.3), new Cartesian3(0.25, 0, -5.3)};
     BoundingSphere tileOccluderSphere = BoundingSphere.fromPoints(positions);
     Cartesian3 occludeePosition = tileOccluderSphere.center;
     Object occludeePt = Occluder.computeOccludeePoint(occluderBoundingSphere, occludeePosition, positions);
     
 

Parameters:

occluderBoundingSphere - The bounding sphere surrounding the occluder.

occludeePosition - List of altitude points on the horizon near the surface of the occluder.

positions - An object containing two attributes: occludeePoint and valid which is a boolean value.

Returns:

An object containing two attributes: occludeePoint and valid which is a boolean value.

computeOccludeePointFromRectangle

@JsMethod
public static Object computeOccludeePointFromRectangle(Rectangle rectangle)

Computes a point that can be used as the occludee position to the visibility functions from an rectangle.

Parameters:

rectangle - The rectangle used to create a bounding sphere.

Returns:

An object containing two attributes: occludeePoint and valid which is a boolean value.

computeOccludeePointFromRectangle

@JsMethod
public static Object computeOccludeePointFromRectangle(Rectangle rectangle,
                                                                 Ellipsoid ellipsoid)

Computes a point that can be used as the occludee position to the visibility functions from an rectangle.

Parameters:

rectangle - The rectangle used to create a bounding sphere.

ellipsoid - The ellipsoid used to determine positions of the rectangle. Default: Ellipsoid.WGS84()

Returns:

An object containing two attributes: occludeePoint and valid which is a boolean value.

fromBoundingSphere

@JsMethod
public static Occluder fromBoundingSphere(BoundingSphere occluderBoundingSphere,
                                                    Cartesian3 cameraPosition)

Creates an occluder from a bounding sphere and the camera position.

Parameters:

occluderBoundingSphere - The bounding sphere surrounding the occluder.

cameraPosition - The coordinate of the viewer/camera.

Returns:

The occluder derived from an object's position and radius, as well as the camera position.

fromBoundingSphere

@JsMethod
public static Occluder fromBoundingSphere(BoundingSphere occluderBoundingSphere,
                                                    Cartesian3 cameraPosition,
                                                    Occluder result)

Creates an occluder from a bounding sphere and the camera position.

Parameters:

occluderBoundingSphere - The bounding sphere surrounding the occluder.

cameraPosition - The coordinate of the viewer/camera.

result - The object onto which to store the result.

Returns:

The occluder derived from an object's position and radius, as well as the camera position.

computeVisibility

@JsMethod
public Number computeVisibility(BoundingSphere occludeeBS)

Determine to what extent an occludee is visible (not visible, partially visible, or fully visible).

     Example:
     
     BoundingSphere sphere1 = new BoundingSphere(new Cartesian3(0, 0, -1.5), 0.5);
     BoundingSphere sphere2 = new BoundingSphere(new Cartesian3(0, 0, -2.5), 0.5);
     Cartesian3 cameraPosition = new Cartesian3(0, 0, 0);
     Occluder occluder = new Occluder(sphere1, cameraPosition);
     occluder.computeVisibility(sphere2); //returns Visibility.NONE
     
 

Parameters:

occludeeBS - The bounding sphere of the occludee.

Returns:

Visibility.NONE() if the occludee is not visible, Visibility.PARTIAL() if the occludee is partially visible, or Visibility.FULL() if the occludee is fully visible.

isBoundingSphereVisible

@JsMethod
public boolean isBoundingSphereVisible(BoundingSphere occludee)

Determines whether or not a sphere, the occludee, is hidden from view by the occluder.

     Example:
     
     Cartesian3 cameraPosition = new Cesium.Cartesian3(0, 0, 0);
     BoundingSphere littleSphere = new BoundingSphere(new Cartesian3(0, 0, -1), 0.25);
     Occluder occluder = new Occluder(littleSphere, cameraPosition);
     BoundingSphere bigSphere = new BoundingSphere(new Cartesian3(0, 0, -3), 1);
     occluder.isBoundingSphereVisible(bigSphere); //returns true
     
 

Parameters:

occludee - The bounding sphere surrounding the occludee object.

Returns:

true if the occludee is visible; otherwise false.

See Also:

computeVisibility(BoundingSphere)

isPointVisible

@JsMethod
public boolean isPointVisible(Cartesian3 occludee)

etermines whether or not a point, the occludee, is hidden from view by the occluder.

     Example:
     
     Cartesian3 cameraPosition = new Cartesian3(0, 0, 0);
     BoundingSphere littleSphere = new BoundingSphere(new Cartesian3(0, 0, -1), 0.25);
     Occluder occluder = new Occluder(littleSphere, cameraPosition);
     Cartesian3 point = new Cartesian3(0, 0, -3);
     occluder.isPointVisible(point); //returns true
     
 

Parameters:

occludee - The point surrounding the occludee object.

Returns:

true if the occludee is visible; otherwise false.

See Also:

computeVisibility(BoundingSphere)