Scene中包含几何体的卷。
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.
Only PerInstanceColorAppearance with the same color across all instances is supported at this time when using
ClassificationPrimitive directly.
For full Appearance support when classifying terrain or 3D Tiles use GroundPrimitive instead.
For correct rendering, this feature requires the EXT_frag_depth WebGL extension. For hardware that do not support this extension, there will be rendering artifacts for some viewing angles.
Valid geometries are BoxGeometry, CylinderGeometry, EllipsoidGeometry, PolylineVolumeGeometry, and SphereGeometry.
Geometries that follow the surface of the ellipsoid, such as CircleGeometry, CorridorGeometry, EllipseGeometry, PolygonGeometry, and RectangleGeometry,
are also valid if they are extruded volumes; otherwise, they will not be rendered.
| Name | Type | Description | ||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
options |
Object | optional
具有以下属性的对象：
|
Members
-
Default Value:
true
-
Default Value:
true
classificationType : ClassificationType
-
Default Value:
ClassificationType.BOTH
true时，几何体顶点被压缩，这将节省内存。-
Default Value:
true
Draws the bounding sphere for each draw command in the primitive.
-
Default Value:
false
Draws the shadow volume for each geometry in the primitive.
-
Default Value:
false
readonly geometryInstances : Array|GeometryInstance
options.releaseGeometryInstances，则为undefined
构造原语时为true。
Changing this property after the primitive is rendered has no effect.
Because of the rendering technique used, all geometry instances must be the same color.
If there is an instance with a differing color, a DeveloperError will be thrown
on the first attempt to render.
-
Default Value:
undefined
-
Default Value:
false
ClassificationPrimitive#update
被称为。readonly readyPromise : Promise.<ClassificationPrimitive>
true时，原语不保留对输入geometryInstances的引用以节省内存。-
Default Value:
true
-
Default Value:
true
true时，几何体顶点针对顶点前后着色器缓存进行了优化。-
Default Value:
true
Methods
| Name | Type | Description |
|---|---|---|
scene |
Scene | 现场。 |
Returns:
true；否则，返回false
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 ：此对象已销毁，即调用destroy（）。
Example:
e = e && e.destroy();See:
GeometryInstance的每个实例的可修改属性。| Name | Type | Description |
|---|---|---|
id |
* | GeometryInstance的id。 |
Returns:
Throws:
-
DeveloperError ：必须在调用getGeometryInstanceAttributes之前调用update。
Example:
var attributes = primitive.getGeometryInstanceAttributes('an id');
attributes.color = Cesium.ColorGeometryInstanceAttribute.toValue(Cesium.Color.AQUA);
attributes.show = Cesium.ShowGeometryInstanceAttribute.toValue(true);
If this object was destroyed, it should not be used; calling any function other than
isDestroyed will result in a DeveloperError exception.
Returns:
true；否则为false。Viewer或CesiumWidget将场景渲染到
获取渲染此基本体所需的draw命令。
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 ：所有实例几何图形必须具有相同的基本类型。
-
DeveloperError ：外观和材质具有相同名称的制服。
-
DeveloperError ：并非所有几何体实例都具有相同的颜色属性。