QuantizedMeshTerrainData
查阅Mars3D API

new Cesium.QuantizedMeshTerrainData(options)
engine/Source/Core/QuantizedMeshTerrainData.js 94

Terrain data for a single tile where the terrain data is represented as a quantized mesh. A quantized mesh consists of three vertex attributes, longitude, latitude, and height. All attributes are expressed as 16-bit values in the range 0 to 32767. Longitude and latitude are zero at the southwest corner of the tile and 32767 at the northeast corner. Height is zero at the minimum height in the tile and 32767 at the maximum height in the tile.
参数名称 类型 描述信息
options object Object with the following properties:
参数名称 类型 默认值 描述信息
quantizedVertices Uint16Array The buffer containing the quantized mesh.
indices Uint16Array | Uint32Array The indices specifying how the quantized vertices are linked together into triangles. Each three indices specifies one triangle.
minimumHeight number The minimum terrain height within the tile, in meters above the ellipsoid.
maximumHeight number The maximum terrain height within the tile, in meters above the ellipsoid.
boundingSphere BoundingSphere A sphere bounding all of the vertices in the mesh.
orientedBoundingBox OrientedBoundingBox 可选 An OrientedBoundingBox bounding all of the vertices in the mesh.
horizonOcclusionPoint Cartesian3 The horizon occlusion point of the mesh. If this point is below the horizon, the entire tile is assumed to be below the horizon as well. The point is expressed in ellipsoid-scaled coordinates.
westIndices Array.<number> The indices of the vertices on the western edge of the tile.
southIndices Array.<number> The indices of the vertices on the southern edge of the tile.
eastIndices Array.<number> The indices of the vertices on the eastern edge of the tile.
northIndices Array.<number> The indices of the vertices on the northern edge of the tile.
westSkirtHeight number The height of the skirt to add on the western edge of the tile.
southSkirtHeight number The height of the skirt to add on the southern edge of the tile.
eastSkirtHeight number The height of the skirt to add on the eastern edge of the tile.
northSkirtHeight number The height of the skirt to add on the northern edge of the tile.
childTileMask number 15 可选 A bit mask indicating which of this tile's four children exist. If a child's bit is set, geometry will be requested for that tile as well when it is needed. If the bit is cleared, the child tile is not requested and geometry is instead upsampled from the parent. The bit values are as follows:
Bit PositionBit ValueChild Tile
01Southwest
12Southeast
24Northwest
38Northeast
createdByUpsampling boolean false 可选 True if this instance was created by upsampling another instance; otherwise, false.
encodedNormals Uint8Array 可选 The buffer containing per vertex normals, encoded using 'oct' encoding
waterMask Uint8Array 可选 The buffer containing the watermask.
credits Array.<Credit> 可选 Array of credits for this tile.
使用示例:
const data = new Cesium.QuantizedMeshTerrainData({
    minimumHeight : -100,
    maximumHeight : 2101,
    quantizedVertices : new Uint16Array([// order is SW NW SE NE
                                         // longitude
                                         0, 0, 32767, 32767,
                                         // latitude
                                         0, 32767, 0, 32767,
                                         // heights
                                         16384, 0, 32767, 16384]),
    indices : new Uint16Array([0, 3, 1,
                               0, 2, 3]),
    boundingSphere : new Cesium.BoundingSphere(new Cesium.Cartesian3(1.0, 2.0, 3.0), 10000),
    orientedBoundingBox : new Cesium.OrientedBoundingBox(new Cesium.Cartesian3(1.0, 2.0, 3.0), Cesium.Matrix3.fromRotationX(Cesium.Math.PI, new Cesium.Matrix3())),
    horizonOcclusionPoint : new Cesium.Cartesian3(3.0, 2.0, 1.0),
    westIndices : [0, 1],
    southIndices : [0, 1],
    eastIndices : [2, 3],
    northIndices : [1, 3],
    westSkirtHeight : 1.0,
    southSkirtHeight : 1.0,
    eastSkirtHeight : 1.0,
    northSkirtHeight : 1.0
});
参考:

成员(属性)

credits : Array.<Credit>
engine/Source/Core/QuantizedMeshTerrainData.js 216

An array of credits for this tile.

waterMask : Uint8Array|HTMLImageElement|HTMLCanvasElement
engine/Source/Core/QuantizedMeshTerrainData.js 228

The water mask included in this terrain data, if any. A water mask is a rectangular Uint8Array or image where a value of 255 indicates water and a value of 0 indicates land. Values in between 0 and 255 are allowed as well to smoothly blend between land and water.

方法

interpolateHeight(rectangle, longitude, latitude) → number
engine/Source/Core/QuantizedMeshTerrainData.js 571

Computes the terrain height at a specified longitude and latitude.
参数名称 类型 描述信息
rectangle Rectangle The rectangle covered by this terrain data.
longitude number The longitude in radians.
latitude number The latitude in radians.
返回值:
The terrain height at the specified position. The position is clamped to the rectangle, so expect incorrect results for positions far outside the rectangle.

isChildAvailable(thisX, thisY, childX, childY) → boolean
engine/Source/Core/QuantizedMeshTerrainData.js 729

Determines if a given child tile is available, based on the HeightmapTerrainData.childTileMask. The given child tile coordinates are assumed to be one of the four children of this tile. If non-child tile coordinates are given, the availability of the southeast child tile is returned.
参数名称 类型 描述信息
thisX number The tile X coordinate of this (the parent) tile.
thisY number The tile Y coordinate of this (the parent) tile.
childX number The tile X coordinate of the child tile to check for availability.
childY number The tile Y coordinate of the child tile to check for availability.
返回值:
True if the child tile is available; otherwise, false.

upsample(tilingScheme, thisX, thisY, thisLevel, descendantX, descendantY, descendantLevel) → Promise.<QuantizedMeshTerrainData>|undefined
engine/Source/Core/QuantizedMeshTerrainData.js 431

Upsamples this terrain data for use by a descendant tile. The resulting instance will contain a subset of the vertices in this instance, interpolated if necessary.
参数名称 类型 描述信息
tilingScheme TilingScheme The tiling scheme of this terrain data.
thisX number The X coordinate of this tile in the tiling scheme.
thisY number The Y coordinate of this tile in the tiling scheme.
thisLevel number The level of this tile in the tiling scheme.
descendantX number The X coordinate within the tiling scheme of the descendant tile for which we are upsampling.
descendantY number The Y coordinate within the tiling scheme of the descendant tile for which we are upsampling.
descendantLevel number The level within the tiling scheme of the descendant tile for which we are upsampling.
返回值:
A promise for upsampled heightmap terrain data for the descendant tile, or undefined if too many asynchronous upsample operations are in progress and the request has been deferred.

wasCreatedByUpsampling() → boolean
engine/Source/Core/QuantizedMeshTerrainData.js 769

Gets a value indicating whether or not this terrain data was created by upsampling lower resolution terrain data. If this value is false, the data was obtained from some other source, such as by downloading it from a remote server. This method should return true for instances returned from a call to HeightmapTerrainData#upsample.
返回值:
True if this instance was created by upsampling; otherwise, false.
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