BillboardCollection

new BillboardCollection(options)

A renderable collection of billboards. Billboards are viewport-aligned images positioned in the 3D scene.


Example billboards


Billboards are added and removed from the collection using BillboardCollection#add and BillboardCollection#remove. Billboards in a collection automatically share textures for images with the same identifier.
Performance:

For best performance, prefer a few collections, each with many billboards, to many collections with only a few billboards each. Organize collections so that billboards with the same update frequency are in the same collection, i.e., billboards that do not change should be in one collection; billboards that change every frame should be in another collection; and so on.

Name Type Description
options Object optional Object with the following properties:
Name Type Default Description
modelMatrix Matrix4 Matrix4.IDENTITY optional The 4x4 transformation matrix that transforms each billboard from model to world coordinates.
debugShowBoundingVolume Boolean false optional For debugging only. Determines if this primitive's commands' bounding spheres are shown.
Example:
// Create a billboard collection with two billboards
var billboards = new Cesium.BillboardCollection();
billboards.add({
  position : { x : 1.0, y : 2.0, z : 3.0 },
  image : 'url/to/image'
});
billboards.add({
  position : { x : 4.0, y : 5.0, z : 6.0 },
  image : 'url/to/another/image'
});
Demo:
See:
Source: Scene/BillboardCollection.js, line 132

Members

debugShowBoundingVolume :Boolean

This property is for debugging only; it is not for production use nor is it optimized.

Draws the bounding sphere for each draw command in the primitive.

Default Value: false
Source: Scene/BillboardCollection.js, line 230

length :Number

Returns the number of billboards in this collection. This is commonly used with BillboardCollection#get to iterate over all the billboards in the collection.
Source: Scene/BillboardCollection.js, line 268

modelMatrix :Matrix4

The 4x4 transformation matrix that transforms each billboard in this collection from model to world coordinates. When this is the identity matrix, the billboards are drawn in world coordinates, i.e., Earth's WGS84 coordinates. Local reference frames can be used by providing a different transformation matrix, like that returned by Transforms.eastNorthUpToFixedFrame.
Default Value: Matrix4.IDENTITY
Example:
var center = Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883);
billboards.modelMatrix = Cesium.Transforms.eastNorthUpToFixedFrame(center);
billboards.add({
  image : 'url/to/image',
  position : new Cesium.Cartesian3(0.0, 0.0, 0.0) // center
});
billboards.add({
  image : 'url/to/image',
  position : new Cesium.Cartesian3(1000000.0, 0.0, 0.0) // east
});
billboards.add({
  image : 'url/to/image',
  position : new Cesium.Cartesian3(0.0, 1000000.0, 0.0) // north
});
billboards.add({
  image : 'url/to/image',
  position : new Cesium.Cartesian3(0.0, 0.0, 1000000.0) // up
});
See:
Source: Scene/BillboardCollection.js, line 217

Methods

add(billboard) → Billboard

Creates and adds a billboard with the specified initial properties to the collection. The added billboard is returned so it can be modified or removed from the collection later.
Performance:

Calling add is expected constant time. However, the collection's vertex buffer is rewritten - an O(n) operation that also incurs CPU to GPU overhead. For best performance, add as many billboards as possible before calling update.

Name Type Description
billboard Object optional A template describing the billboard's properties as shown in Example 1.
Returns:
The billboard that was added to the collection.
Throws:
  • DeveloperError : This object was destroyed, i.e., destroy() was called.
Examples:
// Example 1:  Add a billboard, specifying all the default values.
var b = billboards.add({
  show : true,
  position : Cesium.Cartesian3.ZERO,
  pixelOffset : Cesium.Cartesian2.ZERO,
  eyeOffset : Cesium.Cartesian3.ZERO,
  horizontalOrigin : Cesium.HorizontalOrigin.CENTER,
  verticalOrigin : Cesium.VerticalOrigin.CENTER,
  scale : 1.0,
  image : 'url/to/image',
  color : Cesium.Color.WHITE,
  id : undefined
});
// Example 2:  Specify only the billboard's cartographic position.
var b = billboards.add({
  position : Cesium.Cartesian3.fromDegrees(longitude, latitude, height)
});
See:
Source: Scene/BillboardCollection.js, line 365

contains(billboard) → Boolean

Check whether this collection contains a given billboard.
Name Type Description
billboard Billboard optional The billboard to check for.
Returns:
true if this collection contains the billboard, false otherwise.
See:
Source: Scene/BillboardCollection.js, line 470

destroy() → undefined

Destroys the WebGL resources held by this object. Destroying an object allows for deterministic release of WebGL resources, instead of relying on the garbage collector to destroy this object.

Once an object is destroyed, it should not be used; calling any function other than isDestroyed will result in a DeveloperError exception. Therefore, assign the return value (undefined) to the object as done in the example.
Returns:
Throws:
  • DeveloperError : This object was destroyed, i.e., destroy() was called.
Example:
billboards = billboards && billboards.destroy();
See:
Source: Scene/BillboardCollection.js, line 1356

get(index) → Billboard

Returns the billboard in the collection at the specified index. Indices are zero-based and increase as billboards are added. Removing a billboard shifts all billboards after it to the left, changing their indices. This function is commonly used with BillboardCollection#length to iterate over all the billboards in the collection.
Performance:

Expected constant time. If billboards were removed from the collection and BillboardCollection#update was not called, an implicit O(n) operation is performed.

Name Type Description
index Number The zero-based index of the billboard.
Returns:
The billboard at the specified index.
Throws:
  • DeveloperError : This object was destroyed, i.e., destroy() was called.
Example:
// Toggle the show property of every billboard in the collection
var len = billboards.length;
for (var i = 0; i < len; ++i) {
  var b = billboards.get(i);
  b.show = !b.show;
}
See:
Source: Scene/BillboardCollection.js, line 500

isDestroyed() → Boolean

Returns true if this object was destroyed; otherwise, false.

If this object was destroyed, it should not be used; calling any function other than isDestroyed will result in a DeveloperError exception.
Returns:
true if this object was destroyed; otherwise, false.
See:
Source: Scene/BillboardCollection.js, line 1335

remove(billboard) → Boolean

Removes a billboard from the collection.
Performance:

Calling remove is expected constant time. However, the collection's vertex buffer is rewritten - an O(n) operation that also incurs CPU to GPU overhead. For best performance, remove as many billboards as possible before calling update. If you intend to temporarily hide a billboard, it is usually more efficient to call Billboard#show instead of removing and re-adding the billboard.

Name Type Description
billboard Billboard The billboard to remove.
Returns:
true if the billboard was removed; false if the billboard was not found in the collection.
Throws:
  • DeveloperError : This object was destroyed, i.e., destroy() was called.
Example:
var b = billboards.add(...);
billboards.remove(b);  // Returns true
See:
Source: Scene/BillboardCollection.js, line 397

removeAll()

Removes all billboards from the collection.
Performance:

O(n). It is more efficient to remove all the billboards from a collection and then add new ones than to create a new collection entirely.

Throws:
  • DeveloperError : This object was destroyed, i.e., destroy() was called.
Example:
billboards.add(...);
billboards.add(...);
billboards.removeAll();
See:
Source: Scene/BillboardCollection.js, line 425

update()

Called when Viewer or CesiumWidget render the scene to get the draw commands needed to render this primitive.

Do not call this function directly. This is documented just to list the exceptions that may be propagated when the scene is rendered:

Throws:
Source: Scene/BillboardCollection.js, line 1017