PointPrimitiveCollection
查阅Mars3D API

new Cesium.PointPrimitiveCollection(options)
engine/Source/Scene/PointPrimitiveCollection.js 93

A renderable collection of points.

Points are added and removed from the collection using PointPrimitiveCollection#add and PointPrimitiveCollection#remove.
Performance:

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

参数名称 类型 描述信息
options object 可选 Object with the following properties:
参数名称 类型 默认值 描述信息
modelMatrix Matrix4 Matrix4.IDENTITY 可选 The 4x4 transformation matrix that transforms each point from model to world coordinates.
debugShowBoundingVolume boolean false 可选 For debugging only. Determines if this primitive's commands' bounding spheres are shown.
blendOption BlendOption BlendOption.OPAQUE_AND_TRANSLUCENT 可选 The point blending option. The default is used for rendering both opaque and translucent points. However, if either all of the points are completely opaque or all are completely translucent, setting the technique to BlendOption.OPAQUE or BlendOption.TRANSLUCENT can improve performance by up to 2x.
show boolean true 可选 Determines if the primitives in the collection will be shown.
使用示例:
// Create a pointPrimitive collection with two points
const points = scene.primitives.add(new Cesium.PointPrimitiveCollection());
points.add({
  position : new Cesium.Cartesian3(1.0, 2.0, 3.0),
  color : Cesium.Color.YELLOW
});
points.add({
  position : new Cesium.Cartesian3(4.0, 5.0, 6.0),
  color : Cesium.Color.CYAN
});
参考:

成员(属性)

blendOption : BlendOption
engine/Source/Scene/PointPrimitiveCollection.js 200

The point blending option. The default is used for rendering both opaque and translucent points. However, if either all of the points are completely opaque or all are completely translucent, setting the technique to BlendOption.OPAQUE or BlendOption.TRANSLUCENT can improve performance by up to 2x.
默认值: BlendOption.OPAQUE_AND_TRANSLUCENT

debugShowBoundingVolume : boolean
engine/Source/Scene/PointPrimitiveCollection.js 187

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.

默认值: false

length : number
engine/Source/Scene/PointPrimitiveCollection.js 238

Returns the number of points in this collection. This is commonly used with PointPrimitiveCollection#get to iterate over all the points in the collection.

modelMatrix : Matrix4
engine/Source/Scene/PointPrimitiveCollection.js 172

The 4x4 transformation matrix that transforms each point in this collection from model to world coordinates. When this is the identity matrix, the pointPrimitives 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.
默认值: Matrix4.IDENTITY
使用示例:
const center = Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883);
pointPrimitives.modelMatrix = Cesium.Transforms.eastNorthUpToFixedFrame(center);
pointPrimitives.add({
  color : Cesium.Color.ORANGE,
  position : new Cesium.Cartesian3(0.0, 0.0, 0.0) // center
});
pointPrimitives.add({
  color : Cesium.Color.YELLOW,
  position : new Cesium.Cartesian3(1000000.0, 0.0, 0.0) // east
});
pointPrimitives.add({
  color : Cesium.Color.GREEN,
  position : new Cesium.Cartesian3(0.0, 1000000.0, 0.0) // north
});
pointPrimitives.add({
  color : Cesium.Color.CYAN,
  position : new Cesium.Cartesian3(0.0, 0.0, 1000000.0) // up
});
参考:

show : boolean
engine/Source/Scene/PointPrimitiveCollection.js 138

Determines if primitives in this collection will be shown.
默认值: true

方法

add(options) → PointPrimitive
engine/Source/Scene/PointPrimitiveCollection.js 290

Creates and adds a point with the specified initial properties to the collection. The added point 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 pointPrimitives as possible before calling update.

参数名称 类型 描述信息
options object 可选 A template describing the point's properties as shown in Example 1.
返回值:
The point that was added to the collection.
Throws:
  • DeveloperError : This object was destroyed, i.e., destroy() was called.
使用示例s:
// Example 1:  Add a point, specifying all the default values.
const p = pointPrimitives.add({
  show : true,
  position : Cesium.Cartesian3.ZERO,
  pixelSize : 10.0,
  color : Cesium.Color.WHITE,
  outlineColor : Cesium.Color.TRANSPARENT,
  outlineWidth : 0.0,
  id : undefined
});
// Example 2:  Specify only the point's cartographic position.
const p = pointPrimitives.add({
  position : Cesium.Cartesian3.fromDegrees(longitude, latitude, height)
});
参考:

contains(pointPrimitive) → boolean
engine/Source/Scene/PointPrimitiveCollection.js 401

Check whether this collection contains a given point.
参数名称 类型 描述信息
pointPrimitive PointPrimitive 可选 The point to check for.
返回值:
true if this collection contains the point, false otherwise.
参考:

destroy()
engine/Source/Scene/PointPrimitiveCollection.js 1222

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.
Throws:
  • DeveloperError : This object was destroyed, i.e., destroy() was called.
使用示例:
pointPrimitives = pointPrimitives && pointPrimitives.destroy();
参考:

get(index) → PointPrimitive
engine/Source/Scene/PointPrimitiveCollection.js 434

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

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

参数名称 类型 描述信息
index number The zero-based index of the point.
返回值:
The point at the specified index.
Throws:
  • DeveloperError : This object was destroyed, i.e., destroy() was called.
使用示例:
// Toggle the show property of every point in the collection
const len = pointPrimitives.length;
for (let i = 0; i < len; ++i) {
  const p = pointPrimitives.get(i);
  p.show = !p.show;
}
参考:

isDestroyed() → boolean
engine/Source/Scene/PointPrimitiveCollection.js 1202

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.
返回值:
true if this object was destroyed; otherwise, false.
参考:

remove(pointPrimitive) → boolean
engine/Source/Scene/PointPrimitiveCollection.js 323

Removes a point 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 points as possible before calling update. If you intend to temporarily hide a point, it is usually more efficient to call PointPrimitive#show instead of removing and re-adding the point.

参数名称 类型 描述信息
pointPrimitive PointPrimitive The point to remove.
返回值:
true if the point was removed; false if the point was not found in the collection.
Throws:
  • DeveloperError : This object was destroyed, i.e., destroy() was called.
使用示例:
const p = pointPrimitives.add(...);
pointPrimitives.remove(p);  // Returns true
参考:

removeAll()
engine/Source/Scene/PointPrimitiveCollection.js 352

Removes all points from the collection.
Performance:

O(n). It is more efficient to remove all the points 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.
使用示例:
pointPrimitives.add(...);
pointPrimitives.add(...);
pointPrimitives.removeAll();
参考:
packages/engine
packages/widgets