TerrainProvider

Members

<static> attributeIndices

Specifies the indices of the attributes of the terrain geometry.

<static> heightmapTerrainQuality

Specifies the quality of terrain created from heightmaps. A value of 1.0 will ensure that adjacent heightmap vertices are separated by no more than CentralBodySurface._maxScreenSpaceError screen pixels and will probably go very slowly. A value of 0.5 will cut the estimated level zero geometric error in half, allowing twice the screen pixels between adjacent heightmap vertices and thus rendering more quickly.

Methods

getErrorEvent

Gets an event that is raised when the terrain provider encounters an asynchronous error. By subscribing to the event, you will be notified of the error and can potentially recover from it. Event listeners are passed an instance of TileProviderError.

Returns:

Event The event.

getLevelMaximumGeometricError

Gets the maximum geometric error allowed in a tile at a given level. This function should not be called before TerrainProvider#isReady returns true.

Parameters:

Name	Type	Description
level	Number	The tile level for which to get the maximum geometric error.

Returns:

Number The maximum geometric error.

getLogo

Gets the logo to display when this terrain provider is active. Typically this is used to credit the source of the terrain. This function should not be called before TerrainProvider#isReady returns true.

Throws:

DeveloperError : getLogo must not be called before the terrain provider is ready.

Returns:

Image | Canvas A canvas or image containing the log to display, or undefined if there is no logo.

getTilingScheme

Gets the tiling scheme used by this provider. This function should not be called before TerrainProvider#isReady returns true.

Throws:

DeveloperError : getTilingScheme must not be called before the terrain provider is ready.

Returns:

GeographicTilingScheme The tiling scheme.

See:

• WebMercatorTilingScheme
• GeographicTilingScheme

hasWaterMask

Gets a value indicating whether or not the provider includes a water mask. The water mask indicates which areas of the globe are water rather than land, so they can be rendered as a reflective surface with animated waves. This function should not be called before TerrainProvider#isReady returns true.

Returns:

Boolean True if the provider has a water mask; otherwise, false.

isReady

Gets a value indicating whether or not the provider is ready for use.

Returns:

Boolean True if the provider is ready to use; otherwise, false.

requestTileGeometry

Requests the geometry for a given tile. This function should not be called before TerrainProvider#isReady returns true. The result must include terrain data and may optionally include a water mask and an indication of which child tiles are available.

Parameters:

Name	Type	Argument	Default	Description
x	Number			The X coordinate of the tile for which to request geometry.
y	Number			The Y coordinate of the tile for which to request geometry.
level	Number			The level of the tile for which to request geometry.
throttleRequests	Boolean	<optional>	true	True if the number of simultaneous requests should be limited, or false if the request should be initiated regardless of the number of requests already in progress.

Returns:

Promise | TerrainData A promise for the requested geometry. If this method returns undefined instead of a promise, it is an indication that too many requests are already pending and the request will be retried later.

<static> getEstimatedLevelZeroGeometricErrorForAHeightmap

Determines an appropriate geometric error estimate when the geometry comes from a heightmap.

Parameters:

Name	Type	Description
ellipsoid		The ellipsoid to which the terrain is attached.
tileImageWidth		The width, in pixels, of the heightmap associated with a single tile.
numberOfTilesAtLevelZero		The number of tiles in the horizontal direction at tile level zero.

Returns:

Number An estimated geometric error.