GroundPolylinePrimitive

new Cesium.GroundPolylinePrimitive(options)
engine/Source/Scene/GroundPolylinePrimitive.js 97

A GroundPolylinePrimitive represents a polyline draped over the terrain or 3D Tiles in the Scene.

Only to be used with GeometryInstances containing GroundPolylineGeometry.

Name Type Description
options object optional Object with the following properties:
Name Type Default Description
geometryInstances Array | GeometryInstance optional GeometryInstances containing GroundPolylineGeometry
appearance Appearance optional The Appearance used to render the polyline. Defaults to a white color Material on a PolylineMaterialAppearance.
show boolean true optional Determines if this primitive will be shown.
interleave boolean false optional When true, geometry vertex attributes are interleaved, which can slightly improve rendering performance but increases load time.
releaseGeometryInstances boolean true optional When true, the primitive does not keep a reference to the input geometryInstances to save memory.
allowPicking boolean true optional When true, each geometry instance will only be pickable with Scene#pick. When false, GPU memory is saved.
asynchronous boolean true optional Determines if the primitive will be created asynchronously or block until ready. If false initializeTerrainHeights() must be called first.
classificationType ClassificationType ClassificationType.BOTH optional Determines whether terrain, 3D Tiles or both will be classified.
debugShowBoundingVolume boolean false optional For debugging only. Determines if this primitive's commands' bounding spheres are shown.
debugShowShadowVolume boolean false optional For debugging only. Determines if the shadow volume for each geometry in the primitive is drawn. Must be true on creation to have effect.
Example:
// 1. Draw a polyline on terrain with a basic color material

const instance = new Cesium.GeometryInstance({
  geometry : new Cesium.GroundPolylineGeometry({
     positions : Cesium.Cartesian3.fromDegreesArray([
         -112.1340164450331, 36.05494287836128,
         -112.08821010582645, 36.097804071380715
     ]),
     width : 4.0
  }),
  id : 'object returned when this instance is picked and to get/set per-instance attributes'
});

scene.groundPrimitives.add(new Cesium.GroundPolylinePrimitive({
  geometryInstances : instance,
  appearance : new Cesium.PolylineMaterialAppearance()
}));

// 2. Draw a looped polyline on terrain with per-instance color and a distance display condition.
// Distance display conditions for polylines on terrain are based on an approximate terrain height
// instead of true terrain height.

const instance2 = new Cesium.GeometryInstance({
  geometry : new Cesium.GroundPolylineGeometry({
     positions : Cesium.Cartesian3.fromDegreesArray([
         -112.1340164450331, 36.05494287836128,
         -112.08821010582645, 36.097804071380715,
         -112.13296079730024, 36.168769146801104
     ]),
     loop : true,
     width : 4.0
  }),
  attributes : {
     color : Cesium.ColorGeometryInstanceAttribute.fromColor(Cesium.Color.fromCssColorString('green').withAlpha(0.7)),
     distanceDisplayCondition : new Cesium.DistanceDisplayConditionGeometryInstanceAttribute(1000, 30000)
  },
  id : 'object returned when this instance is picked and to get/set per-instance attributes'
});

scene.groundPrimitives.add(new Cesium.GroundPolylinePrimitive({
  geometryInstances : instance2,
  appearance : new Cesium.PolylineColorAppearance()
}));

Members

readonly allowPicking : boolean
engine/Source/Scene/GroundPolylinePrimitive.js 280

When true, each geometry instance will only be pickable with Scene#pick. When false, GPU memory is saved.
Default Value: true

appearance : Appearance
engine/Source/Scene/GroundPolylinePrimitive.js 130

The Appearance used to shade this primitive. Each geometry instance is shaded with the same appearance. Some appearances, like PolylineColorAppearance allow giving each instance unique properties.
Default Value: undefined

readonly asynchronous : boolean
engine/Source/Scene/GroundPolylinePrimitive.js 296

Determines if the geometry instances will be created and batched on a web worker.
Default Value: true

classificationType : ClassificationType
engine/Source/Scene/GroundPolylinePrimitive.js 149

Determines whether terrain, 3D Tiles or both will be classified.
Default Value: ClassificationType.BOTH

debugShowBoundingVolume : boolean
engine/Source/Scene/GroundPolylinePrimitive.js 164

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

readonly debugShowShadowVolume : boolean
engine/Source/Scene/GroundPolylinePrimitive.js 348

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

If true, draws the shadow volume for each geometry in the primitive.

Default Value: false

readonly geometryInstances : Array|GeometryInstance
engine/Source/Scene/GroundPolylinePrimitive.js 113

The geometry instances rendered with this primitive. This may be undefined if options.releaseGeometryInstances is true when the primitive is constructed.

Changing this property after the primitive is rendered has no effect.

Default Value: undefined

readonly interleave : boolean
engine/Source/Scene/GroundPolylinePrimitive.js 248

Determines if geometry vertex attributes are interleaved, which can slightly improve rendering performance.
Default Value: false

readonly ready : boolean
engine/Source/Scene/GroundPolylinePrimitive.js 312

Determines if the primitive is complete and ready to render. If this property is true, the primitive will be rendered the next time that GroundPolylinePrimitive#update is called.

readonly deprecated readyPromise : Promise.<GroundPolylinePrimitive>
engine/Source/Scene/GroundPolylinePrimitive.js 325

Gets a promise that resolves when the primitive is ready to render.

Deprecated: true

readonly releaseGeometryInstances : boolean
engine/Source/Scene/GroundPolylinePrimitive.js 264

When true, the primitive does not keep a reference to the input geometryInstances to save memory.
Default Value: true

show : boolean
engine/Source/Scene/GroundPolylinePrimitive.js 140

Determines if the primitive will be shown. This affects all geometry instances in the primitive.
Default Value: true

Methods

static Cesium.GroundPolylinePrimitive.initializeTerrainHeights() → Promise.<void>
engine/Source/Scene/GroundPolylinePrimitive.js 361

Initializes the minimum and maximum terrain heights. This only needs to be called if you are creating the GroundPolylinePrimitive synchronously.
Returns:
A promise that will resolve once the terrain heights have been loaded.

static Cesium.GroundPolylinePrimitive.isSupported(scene) → boolean
engine/Source/Scene/GroundPolylinePrimitive.js 890

Checks if the given Scene supports GroundPolylinePrimitives. GroundPolylinePrimitives require support for the WEBGL_depth_texture extension.
Name Type Description
scene Scene The current scene.
Returns:
Whether or not the current scene supports GroundPolylinePrimitives.

destroy()
engine/Source/Scene/GroundPolylinePrimitive.js 925

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.
Example:
e = e && e.destroy();
See:

getGeometryInstanceAttributes(id) → object
engine/Source/Scene/GroundPolylinePrimitive.js 870

Returns the modifiable per-instance attributes for a GeometryInstance.
Name Type Description
id * The id of the GeometryInstance.
Returns:
The typed array in the attribute's format or undefined if the is no instance with id.
Throws:
  • DeveloperError : must call update before calling getGeometryInstanceAttributes.
Example:
const attributes = primitive.getGeometryInstanceAttributes('an id');
attributes.color = Cesium.ColorGeometryInstanceAttribute.toValue(Cesium.Color.AQUA);
attributes.show = Cesium.ShowGeometryInstanceAttribute.toValue(true);

isDestroyed() → boolean
engine/Source/Scene/GroundPolylinePrimitive.js 905

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:

update()
engine/Source/Scene/GroundPolylinePrimitive.js 711

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:
  • DeveloperError : For synchronous GroundPolylinePrimitives, you must call GroundPolylinePrimitives.initializeTerrainHeights() and wait for the returned promise to resolve.
  • DeveloperError : All GeometryInstances must have color attributes to use PolylineColorAppearance with GroundPolylinePrimitive.
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