EllipsoidalOccluder

// Construct an ellipsoidal occluder with radii 1.0, 1.1, and 0.9.
var cameraPosition = new Cartesian3(5.0, 6.0, 7.0);
var occluderEllipsoid = new Ellipsoid(1.0, 1.1, 0.9);
var occluder = new EllipsoidalOccluder(occluderEllipsoid, cameraPosition);

Methods

getCameraPosition

Gets the position of the camera.

Returns:

Cartesian3 The position of the camera.

getEllipsoid

Returns the occluding ellipsoid.

Returns:

Ellipsoid The ellipsoid.

isPointVisible

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

Parameters:

Name	Type	Description
occludee	Cartesian3	The point to test for visibility.

Returns:

boolean true if the occludee is visible; otherwise false.

Example

var cameraPosition = new Cartesian3(0, 0, 2.5);
var ellipsoid = new Ellipsoid(1.0, 1.1, 0.9);
var occluder = new EllipsoidalOccluder(ellipsoid, cameraPosition);
var point = new Cartesian3(0, -3, -3);
occluder.isPointVisible(point); //returns true

isScaledSpacePointVisible

Determines whether or not a point expressed in the ellipsoid scaled space, is hidden from view by the occluder. To transform a Cartesian X, Y, Z position in the coordinate system aligned with the ellipsoid into the scaled space, call Ellipsoid#transformPositionToScaledSpace.

Parameters:

Name	Type	Description
occludeeScaledSpacePosition	Cartesian3	The point to test for visibility, represented in the scaled space.

Returns:

boolean true if the occludee is visible; otherwise false.

Example

var cameraPosition = new Cartesian3(0, 0, 2.5);
var ellipsoid = new Ellipsoid(1.0, 1.1, 0.9);
var occluder = new EllipsoidalOccluder(ellipsoid, cameraPosition);
var point = new Cartesian3(0, -3, -3);
var scaledSpacePoint = ellipsoid.transformPositionToScaledSpace(point);
occluder.isScaledSpacePointVisible(scaledSpacePoint); //returns true

setCameraPosition

Sets the position of the camera.

Parameters:

Name	Type	Description
cameraPosition	Cartesian3	The new position of the camera.

<static> prototype.computeHorizonCullingPoint

Computes a point that can be used for horizon culling from a list of positions. If the point is below the horizon, all of the positions are guaranteed to be below the horizon as well. The returned point is expressed in the ellipsoid-scaled space and is suitable for use with EllipsoidalOccluder#isScaledSpacePointVisible.

Parameters:

Name	Type	Argument	Description
directionToPoint	Cartesian3		The direction that the computed point will lie along. A reasonable direction to use is the direction from the center of the ellipsoid to the center of the bounding sphere computed from the positions. The direction need not be normalized.
positions	Cartesian3[]		The positions from which to compute the horizon culling point. The positions must be expressed in a reference frame centered at the ellipsoid and aligned with the ellipsoid's axes.
result	Cartesian3	<optional>	The instance on which to store the result instead of allocating a new instance.

Returns:

Cartesian3 The computed horizon culling point, expressed in the ellipsoid-scaled space.

<static> prototype.computeHorizonCullingPointFromExtent

Computes a point that can be used for horizon culling of an extent. If the point is below the horizon, the ellipsoid-conforming extent is guaranteed to be below the horizon as well. The returned point is expressed in the ellipsoid-scaled space and is suitable for use with EllipsoidalOccluder#isScaledSpacePointVisible.

Parameters:

Name	Type	Argument	Description
extent	Extent		The extent for which to compute the horizon culling point.
ellipsoid	Ellipsoid		The ellipsoid on which the extent is defined. This may be different from the ellipsoid used by this instance for occlusion testing.
result	Cartesian3	<optional>	The instance on which to store the result instead of allocating a new instance.

Returns:

Cartesian3 The computed horizon culling point, expressed in the ellipsoid-scaled space.

<static> prototype.computeHorizonCullingPointFromVertices

Computes a point that can be used for horizon culling from a list of positions. If the point is below the horizon, all of the positions are guaranteed to be below the horizon as well. The returned point is expressed in the ellipsoid-scaled space and is suitable for use with EllipsoidalOccluder#isScaledSpacePointVisible.

Parameters:

Name	Type	Argument	Default	Description
directionToPoint	Cartesian3			The direction that the computed point will lie along. A reasonable direction to use is the direction from the center of the ellipsoid to the center of the bounding sphere computed from the positions. The direction need not be normalized.
vertices	Number[]			The vertices from which to compute the horizon culling point. The positions must be expressed in a reference frame centered at the ellipsoid and aligned with the ellipsoid's axes.
stride	Number	<optional>	3
center	Cartesian3	<optional>	Cartesian3.ZERO
result	Cartesian3	<optional>		The instance on which to store the result instead of allocating a new instance.

Returns:

Cartesian3 The computed horizon culling point, expressed in the ellipsoid-scaled space.