Cesium: Class: Primitive

new Primitive(optionsopt)

A primitive represents geometry in the Scene. The geometry can be from a single GeometryInstance as shown in example 1 below, or from an array of instances, even if the geometry is from different geometry types, e.g., an RectangleGeometry and an EllipsoidGeometry as shown in Code Example 2.

A primitive combines geometry instances with an Appearance that describes the full shading, including Material and RenderState. Roughly, the geometry instance defines the structure and placement, and the appearance defines the visual characteristics. Decoupling geometry and appearance allows us to mix and match most of them and add a new geometry or appearance independently of each other.

Combining multiple instances into one primitive is called batching, and significantly improves performance for static data. Instances can be individually picked; Scene#pick returns their GeometryInstance#id. Using per-instance appearances like PerInstanceColorAppearance, each instance can also have a unique color.

Geometry can either be created and batched on a web worker or the main thread. The first two examples show geometry that will be created on a web worker by using the descriptions of the geometry. The third example shows how to create the geometry on the main thread by explicitly calling the createGeometry method.

Parameters:

Name Type Attributes Description

options

Object

Object with the following properties:

Properties

Name	Type	Attributes	Default	Description
`geometryInstances`	Array.<GeometryInstance> \| GeometryInstance	<optional>		The geometry instances - or a single geometry instance - to render.
`appearance`	Appearance	<optional>		The appearance used to render the primitive.
`show`	Boolean	<optional>	true	Determines if this primitive will be shown.
`modelMatrix`	Matrix4	<optional>	Matrix4.IDENTITY	The 4x4 transformation matrix that transforms the primitive (all geometry instances) from model to world coordinates.
`vertexCacheOptimize`	Boolean	<optional>	false	When `true`, geometry vertices are optimized for the pre and post-vertex-shader caches.
`interleave`	Boolean	<optional>	false	When `true`, geometry vertex attributes are interleaved, which can slightly improve rendering performance but increases load time.
`compressVertices`	Boolean	<optional>	true	When `true`, the geometry vertices are compressed, which will save memory.
`releaseGeometryInstances`	Boolean	<optional>	true	When `true`, the primitive does not keep a reference to the input `geometryInstances` to save memory.
`allowPicking`	Boolean	<optional>	true	When `true`, each geometry instance will only be pickable with `Scene#pick`. When `false`, GPU memory is saved.
`cull`	Boolean	<optional>	true	When `true`, the renderer frustum culls and horizon culls the primitive's commands based on their bounding volume. Set this to `false` for a small performance gain if you are manually culling the primitive.
`asynchronous`	Boolean	<optional>	true	Determines if the primitive will be created asynchronously or block until ready.
`debugShowBoundingVolume`	Boolean	<optional>	false	For debugging only. Determines if this primitive's commands' bounding spheres are shown.
`shadows`	ShadowMode	<optional>	ShadowMode.DISABLED	Determines whether this primitive casts or receives shadows from each light source.

Source:

Scene/Primitive.js, line 198

See:

Examples

// 1. Draw a translucent ellipse on the surface with a checkerboard pattern
var instance = new Cesium.GeometryInstance({
  geometry : new Cesium.EllipseGeometry({
      center : Cesium.Cartesian3.fromDegrees(-100.0, 20.0),
      semiMinorAxis : 500000.0,
      semiMajorAxis : 1000000.0,
      rotation : Cesium.Math.PI_OVER_FOUR,
      vertexFormat : Cesium.VertexFormat.POSITION_AND_ST
  }),
  id : 'object returned when this instance is picked and to get/set per-instance attributes'
});
scene.primitives.add(new Cesium.Primitive({
  geometryInstances : instance,
  appearance : new Cesium.EllipsoidSurfaceAppearance({
    material : Cesium.Material.fromType('Checkerboard')
  })
}));

// 2. Draw different instances each with a unique color
var rectangleInstance = new Cesium.GeometryInstance({
  geometry : new Cesium.RectangleGeometry({
    rectangle : Cesium.Rectangle.fromDegrees(-140.0, 30.0, -100.0, 40.0),
    vertexFormat : Cesium.PerInstanceColorAppearance.VERTEX_FORMAT
  }),
  id : 'rectangle',
  attributes : {
    color : new Cesium.ColorGeometryInstanceAttribute(0.0, 1.0, 1.0, 0.5)
  }
});
var ellipsoidInstance = new Cesium.GeometryInstance({
  geometry : new Cesium.EllipsoidGeometry({
    radii : new Cesium.Cartesian3(500000.0, 500000.0, 1000000.0),
    vertexFormat : Cesium.VertexFormat.POSITION_AND_NORMAL
  }),
  modelMatrix : Cesium.Matrix4.multiplyByTranslation(Cesium.Transforms.eastNorthUpToFixedFrame(
    Cesium.Cartesian3.fromDegrees(-95.59777, 40.03883)), new Cesium.Cartesian3(0.0, 0.0, 500000.0), new Cesium.Matrix4()),
  id : 'ellipsoid',
  attributes : {
    color : Cesium.ColorGeometryInstanceAttribute.fromColor(Cesium.Color.AQUA)
  }
});
scene.primitives.add(new Cesium.Primitive({
  geometryInstances : [rectangleInstance, ellipsoidInstance],
  appearance : new Cesium.PerInstanceColorAppearance()
}));

// 3. Create the geometry on the main thread.
scene.primitives.add(new Cesium.Primitive({
  geometryInstances : new Cesium.GeometryInstance({
      geometry : Cesium.EllipsoidGeometry.createGeometry(new Cesium.EllipsoidGeometry({
        radii : new Cesium.Cartesian3(500000.0, 500000.0, 1000000.0),
        vertexFormat : Cesium.VertexFormat.POSITION_AND_NORMAL
      })),
      modelMatrix : Cesium.Matrix4.multiplyByTranslation(Cesium.Transforms.eastNorthUpToFixedFrame(
        Cesium.Cartesian3.fromDegrees(-95.59777, 40.03883)), new Cesium.Cartesian3(0.0, 0.0, 500000.0), new Cesium.Matrix4()),
      id : 'ellipsoid',
      attributes : {
        color : Cesium.ColorGeometryInstanceAttribute.fromColor(Cesium.Color.AQUA)
      }
  }),
  appearance : new Cesium.PerInstanceColorAppearance()
}));

Members

(readonly) allowPicking :Boolean

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

Type:

Boolean

Default Value:

true

Source:

Scene/Primitive.js, line 423

appearance :Appearance

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

Type:

Appearance

Default Value:

undefined

Source:

Scene/Primitive.js, line 225

(readonly) asynchronous :Boolean

Determines if the geometry instances will be created and batched on a web worker.

Type:

Boolean

Default Value:

true

Source:

Scene/Primitive.js, line 439

(readonly) compressVertices :Boolean

When true, geometry vertices are compressed, which will save memory.

Type:

Boolean

Default Value:

true

Source:

Scene/Primitive.js, line 455

cull :Boolean

When true, the renderer frustum culls and horizon culls the primitive's commands based on their bounding volume. Set this to false for a small performance gain if you are manually culling the primitive.

Type:

Boolean

Default Value:

true

Source:

Scene/Primitive.js, line 276

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.

Type:

Boolean

Default Value:

false

Source:

Scene/Primitive.js, line 288

geometryInstances :Array.<GeometryInstance>|GeometryInstance

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.

Type:

Array.<GeometryInstance> | GeometryInstance

Default Value:

undefined

Source:

Scene/Primitive.js, line 213

(readonly) interleave :Boolean

Determines if geometry vertex attributes are interleaved, which can slightly improve rendering performance.

Type:

Boolean

Default Value:

false

Source:

Scene/Primitive.js, line 391

modelMatrix :Matrix4

The 4x4 transformation matrix that transforms the primitive (all geometry instances) from model to world coordinates. When this is the identity matrix, the primitive is 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.

This property is only supported in 3D mode.

Type:

Matrix4

Default Value:

Matrix4.IDENTITY

Source:

Scene/Primitive.js, line 247

Example

var origin = Cesium.Cartesian3.fromDegrees(-95.0, 40.0, 200000.0);
p.modelMatrix = Cesium.Transforms.eastNorthUpToFixedFrame(origin);

(readonly) ready :Boolean

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

Type:

Boolean

Source:

Scene/Primitive.js, line 471

(readonly) readyPromise :Promise.<Primitive>

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

Type:

Promise.<Primitive>

Source:

Scene/Primitive.js, line 483

(readonly) releaseGeometryInstances :Boolean

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

Type:

Boolean

Default Value:

true

Source:

Scene/Primitive.js, line 407

shadows :ShadowMode

Determines whether this primitive casts or receives shadows from each light source.

Type:

ShadowMode

Default Value:

ShadowMode.DISABLED

Source:

Scene/Primitive.js, line 308

show :Boolean

Determines if the primitive will be shown. This affects all geometry instances in the primitive.

Type:

Boolean

Default Value:

true

Source:

Scene/Primitive.js, line 258

(readonly) vertexCacheOptimize :Boolean

When true, geometry vertices are optimized for the pre and post-vertex-shader caches.

Type:

Boolean

Default Value:

true

Source:

Scene/Primitive.js, line 375

Methods

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.

Source:

Scene/Primitive.js, line 1820

See:

Primitive#isDestroyed

Throws:

This object was destroyed, i.e., destroy() was called.
Type DeveloperError

Returns:

Type: undefined

Example

e = e && e.destroy();

getGeometryInstanceAttributes(id) → {Object}

Returns the modifiable per-instance attributes for a GeometryInstance.

Parameters:

Name	Type	Description
`id`	Object	The id of the `GeometryInstance`.

Source:

Scene/Primitive.js, line 1717

Throws:

must call update before calling getGeometryInstanceAttributes.
Type DeveloperError

Returns:

The typed array in the attribute's format or undefined if the is no instance with id.

Type: Object

Example

var attributes = primitive.getGeometryInstanceAttributes('an id');
attributes.color = Cesium.ColorGeometryInstanceAttribute.toValue(Cesium.Color.AQUA);
attributes.show = Cesium.ShowGeometryInstanceAttribute.toValue(true);
attributes.distanceDisplayCondition = Cesium.DistanceDisplayConditionGeometryInstanceAttribute.toValue(100.0, 10000.0);

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.

Source:

Scene/Primitive.js, line 1797

See:

Primitive#destroy

Returns:

true if this object was destroyed; otherwise, false.

Type: Boolean

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:

Source:

Scene/Primitive.js, line 1565

Throws:

All instance geometries must have the same primitiveType.

Type

DeveloperError
Appearance and material have a uniform with the same name.

Type

DeveloperError
Primitive.modelMatrix is only supported in 3D mode.

Type

DeveloperError
Vertex texture fetch support is required to render primitives with per-instance attributes. The maximum number of vertex texture image units must be greater than zero.

Type

RuntimeError