BufferPolygon
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View bound to the underlying buffer data of a BufferPolygonCollection.

BufferPolygon instances are flyweights: a single BufferPolygon instance can be temporarily bound to any conceptual "polygon" in a BufferPolygonCollection, allowing very large collections to be iterated and updated with a minimal memory footprint.

Represented as one (1) external linear ring of three (3) or more positions. May optionally define one or more internal linear rings ("holes") within the polygon. Each hole is represented as a single index into the positions array, where the vertex at that index is the start of an internal linear ring that continues along the following vertices until reaching either the vertex index of the next hole, or the end of the vertex list. Stores a precomputed triangulation, represented as three vertex indices per triangle.

new Cesium.BufferPolygon()
engine/Source/Scene/BufferPolygon.js 35

Experimental

This feature is not final and is subject to change without Cesium's standard deprecation policy.

参考:

继承

成员(属性)

featureId : number
engine/Source/Scene/BufferPrimitive.js 145

Feature ID associated with the primitive; not required to be unique.
继承自:

readonly holeCount : number
engine/Source/Scene/BufferPolygon.js 241

Count of holes (indices) in this polygon.

readonly outerVertexCount : number
engine/Source/Scene/BufferPolygon.js 202

Count of positions (vertices) in this polygon's outer linear ring, number of VEC3 elements.

readonly outerVertexOffset : number
engine/Source/Scene/BufferPolygon.js 191

Offset in collection position array to first vertex in polygon's outer linear ring, number of VEC3 elements.

show : boolean
engine/Source/Scene/BufferPrimitive.js 157

Whether primitive is shown.
继承自:

readonly triangleCount : number
engine/Source/Scene/BufferPolygon.js 407

Count of triangles in this polygon, number of VEC3 elements.

readonly vertexCount : number
engine/Source/Scene/BufferPolygon.js 141

Count of positions (vertices) in this polygon, including both outer ring and internal rings (holes), number of VEC3 elements.

方法

static Cesium.BufferPolygon.clone(polygon, result) → BufferPolygon
engine/Source/Scene/BufferPolygon.js 111

Copies data from source polygon to result. If the result polygon is not new (the last polygon in the collection) then source and result polygons must have the same vertex counts, hole counts, and triangle counts.
参数名称 类型 描述信息
polygon BufferPolygon
result BufferPolygon
返回值:

getColor(result) → Color
engine/Source/Scene/BufferPrimitive.js 201

Returns the color of primitive.
参数名称 类型 描述信息
result Color
返回值:
继承自:

getHolePositions(holeIndex, result)
engine/Source/Scene/BufferPolygon.js 336

Returns an array view of the inner linear ring vertex positions for the specified hole. If 'result' argument is given, vertex positions are written to that array and returned. Otherwise, returns an ArrayView on collection memory — changes to this array will not trigger render updates, which requires `.setPositions()`.
参数名称 类型 描述信息
holeIndex number
result Float64Array 可选 return {Float64Array}

getHoles(result) → Uint32Array
engine/Source/Scene/BufferPolygon.js 258

Gets this polygon's hole indices, with each hole represented as a single offset into this polygon's positions array. Each hole implicitly continues along an internal linear ring from that vertex offset until reaching either the end of the positions array, or the next hole offset. If 'result' argument is given, hole indices are written to that array and returned. Otherwise, returns an ArrayView on collection memory — changes to this array will not trigger render updates, which requires `.setHoles()`.
参数名称 类型 描述信息
result Uint32Array 可选
返回值:

getHoleVertexCount(holeIndex) → number
engine/Source/Scene/BufferPolygon.js 311

Returns the number of (VEC3) vertices in the specified hole.
参数名称 类型 描述信息
holeIndex number
返回值:

getOuterPositions(result) → Float64Array
engine/Source/Scene/BufferPolygon.js 219

Returns an array view of this polygon's outer linear ring vertex positions. If 'result' argument is given, vertex positions are written to that array and returned. Otherwise, returns an ArrayView on collection memory — changes to this array will not trigger render updates, which requires `.setPositions()`.
参数名称 类型 描述信息
result Float64Array 可选
返回值:

getPositions(result)
engine/Source/Scene/BufferPolygon.js 154

Returns an array view of this polygon's vertex positions. If 'result' argument is given, vertex positions are written to that array and returned. Otherwise, returns an ArrayView on collection memory — changes to this array will not trigger render updates, which requires `.setPositions()`.
参数名称 类型 描述信息
result Float64Array 可选 return {Float64Array}

getTriangles(result) → Uint32Array
engine/Source/Scene/BufferPolygon.js 423

Returns an array view of this polygon's triangle indices, represented as three vertex indices per triangle. If 'result' argument is given, triangle indices are written to that array and returned. Otherwise, returns an ArrayView on collection memory — changes to this array will not trigger render updates, which requires `.setTriangles()`.
参数名称 类型 描述信息
result Uint32Array 可选
返回值:

setColor(color)
engine/Source/Scene/BufferPrimitive.js 212

Updates the color of primitive.
参数名称 类型 描述信息
color Color
继承自:

setHoles(holes)
engine/Source/Scene/BufferPolygon.js 282

Sets this polygon's hole indices, with holes represented as a single offset into this polygon's positions array. Each hole implicitly continues along an internal linear ring from that vertex offset until reaching either the end of the positions array, or the next hole offset.
参数名称 类型 描述信息
holes Uint32Array

setPositions(positions)
engine/Source/Scene/BufferPolygon.js 159

参数名称 类型 描述信息
positions Float64Array

setTriangles(indices)
engine/Source/Scene/BufferPolygon.js 447

Sets this polygon's triangle indices, represented as three vertex indices per triangle.
参数名称 类型 描述信息
indices Uint32Array

toJSON() → Object
engine/Source/Scene/BufferPolygon.js 483

Returns a JSON-serializable object representing the polygon. This encoding is not memory-efficient, and should generally be used for debugging and testing.
返回值:
JSON-serializable object.
继承自:
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