HeightmapTessellator

Members

<static> DEFAULT_STRUCTURE

The default structure of a heightmap, as given to HeightmapTessellator.computeVertices.

Methods

<static> computeVertices

Fills an array of vertices from a heightmap image. On return, the vertex data is in the order [X, Y, Z, H, U, V], where X, Y, and Z represent the Cartesian position of the vertex, H is the height above the ellipsoid, and U and V are the texture coordinates.

Parameters:

Name	Type	Argument	Default	Description
description.vertices	Array | Float32Array			The array to use to store computed vertices. If description.skirtHeight is 0.0, the array should have description.width * description.height * 6 elements. If description.skirtHeight is greater than 0.0, the array should have (description.width + 2) * (description.height * 2) * 6 elements.
description.heightmap	TypedArray			The heightmap to tessellate.
description.width	Number			The width of the heightmap, in height samples.
description.height	Number			The height of the heightmap, in height samples.
description.skirtHeight	Number			The height of skirts to drape at the edges of the heightmap.
description.nativeExtent	Extent			An extent in the native coordinates of the heightmap's projection. For a heightmap with a geographic projection, this is degrees. For the web mercator projection, this is meters.
description.extent	Extent	<optional>		The extent covered by the heightmap, in geodetic coordinates with north, south, east and west properties in radians. Either extent or nativeExtent must be provided. If both are provided, they're assumed to be consistent.
description.isGeographic	Boolean	<optional>	true	True if the heightmap uses a GeographicProjection, or false if it uses a WebMercatorProjection.
description.relativetoCenter	Cartesian3	<optional>	Cartesian3.ZERO	The positions will be computed as worldPosition.subtract(relativeToCenter).
description.ellipsoid	Ellipsoid	<optional>	Ellipsoid.WGS84	The ellipsoid to which the heightmap applies.
description.structure	Object	<optional>		An object describing the structure of the height data. Properties Name Type Argument Default Description heightScale Number <optional> 1.0 The factor by which to multiply height samples in order to obtain the height above the heightOffset, in meters. The heightOffset is added to the resulting height after multiplying by the scale. heightOffset Number <optional> 0.0 The offset to add to the scaled height to obtain the final height in meters. The offset is added after the height sample is multiplied by the heightScale. elementsPerHeight Number <optional> 1 The number of elements in the buffer that make up a single height sample. This is usually 1, indicating that each element is a separate height sample. If it is greater than 1, that number of elements together form the height sample, which is computed according to the structure.elementMultiplier and structure.isBigEndian properties. stride Number <optional> 1 The number of elements to skip to get from the first element of one height to the first element of the next height. elementMultiplier Number <optional> 256.0 The multiplier used to compute the height value when the stride property is greater than 1. For example, if the stride is 4 and the strideMultiplier is 256, the height is computed as follows: `height = buffer[index] + buffer[index + 1] * 256 + buffer[index + 2] * 256 * 256 + buffer[index + 3] * 256 * 256 * 256` This is assuming that the isBigEndian property is false. If it is true, the order of the elements is reversed. isBigEndian Boolean <optional> false Indicates endianness of the elements in the buffer when the stride property is greater than 1. If this property is false, the first element is the low-order element. If it is true, the first element is the high-order element.

Example

var width = 5;
var height = 5;
var vertices = new Float32Array(width * height * 6);
var description = ;
HeightmapTessellator.computeVertices({
    vertices : vertices,
    heightmap : [1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0],
    width : width,
    height : height,
    skirtHeight : 0.0,
    nativeExtent : {
        west : 10.0,
        east : 20.0,
        south : 30.0,
        north : 40.0
    }
});