/*global define*/
define([
'../ThirdParty/when',
'./defaultValue',
'./defined',
'./defineProperties',
'./Ellipsoid',
'./Event',
'./GeographicTilingScheme',
'./HeightmapTerrainData',
'./TerrainProvider'
], function(
when,
defaultValue,
defined,
defineProperties,
Ellipsoid,
Event,
GeographicTilingScheme,
HeightmapTerrainData,
TerrainProvider) {
'use strict';
/**
* A very simple {@link TerrainProvider} that produces geometry by tessellating an ellipsoidal
* surface.
*
* @alias EllipsoidTerrainProvider
* @constructor
*
* @param {Object} [options] Object with the following properties:
* @param {TilingScheme} [options.tilingScheme] The tiling scheme specifying how the ellipsoidal
* surface is broken into tiles. If this parameter is not provided, a {@link GeographicTilingScheme}
* is used.
* @param {Ellipsoid} [options.ellipsoid] The ellipsoid. If the tilingScheme is specified,
* this parameter is ignored and the tiling scheme's ellipsoid is used instead. If neither
* parameter is specified, the WGS84 ellipsoid is used.
*
* @see TerrainProvider
*/
function EllipsoidTerrainProvider(options) {
options = defaultValue(options, {});
this._tilingScheme = options.tilingScheme;
if (!defined(this._tilingScheme)) {
this._tilingScheme = new GeographicTilingScheme({
ellipsoid : defaultValue(options.ellipsoid, Ellipsoid.WGS84)
});
}
// Note: the 64 below does NOT need to match the actual vertex dimensions, because
// the ellipsoid is significantly smoother than actual terrain.
this._levelZeroMaximumGeometricError = TerrainProvider.getEstimatedLevelZeroGeometricErrorForAHeightmap(this._tilingScheme.ellipsoid, 64, this._tilingScheme.getNumberOfXTilesAtLevel(0));
this._errorEvent = new Event();
this._readyPromise = when.resolve(true);
}
defineProperties(EllipsoidTerrainProvider.prototype, {
/**
* 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 {@link TileProviderError}.
* @memberof EllipsoidTerrainProvider.prototype
* @type {Event}
*/
errorEvent : {
get : function() {
return this._errorEvent;
}
},
/**
* Gets the credit 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 {@link EllipsoidTerrainProvider#ready} returns true.
* @memberof EllipsoidTerrainProvider.prototype
* @type {Credit}
*/
credit : {
get : function() {
return undefined;
}
},
/**
* Gets the tiling scheme used by this provider. This function should
* not be called before {@link EllipsoidTerrainProvider#ready} returns true.
* @memberof EllipsoidTerrainProvider.prototype
* @type {GeographicTilingScheme}
*/
tilingScheme : {
get : function() {
return this._tilingScheme;
}
},
/**
* Gets a value indicating whether or not the provider is ready for use.
* @memberof EllipsoidTerrainProvider.prototype
* @type {Boolean}
*/
ready : {
get : function() {
return true;
}
},
/**
* Gets a promise that resolves to true when the provider is ready for use.
* @memberof EllipsoidTerrainProvider.prototype
* @type {Promise.<Boolean>}
* @readonly
*/
readyPromise : {
get : function() {
return this._readyPromise;
}
},
/**
* 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 {@link EllipsoidTerrainProvider#ready} returns true.
* @memberof EllipsoidTerrainProvider.prototype
* @type {Boolean}
*/
hasWaterMask : {
get : function() {
return false;
}
},
/**
* Gets a value indicating whether or not the requested tiles include vertex normals.
* This function should not be called before {@link EllipsoidTerrainProvider#ready} returns true.
* @memberof EllipsoidTerrainProvider.prototype
* @type {Boolean}
*/
hasVertexNormals : {
get : function() {
return false;
}
}
});
/**
* Requests the geometry for a given tile. This function should not be called before
* {@link TerrainProvider#ready} returns true. The result includes terrain
* data and indicates that all child tiles are available.
*
* @param {Number} x The X coordinate of the tile for which to request geometry.
* @param {Number} y The Y coordinate of the tile for which to request geometry.
* @param {Number} level The level of the tile for which to request geometry.
* @param {Boolean} [throttleRequests=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>|undefined} 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.
*/
EllipsoidTerrainProvider.prototype.requestTileGeometry = function(x, y, level, throttleRequests) {
var width = 16;
var height = 16;
return new HeightmapTerrainData({
buffer : new Uint8Array(width * height),
width : width,
height : height
});
};
/**
* Gets the maximum geometric error allowed in a tile at a given level.
*
* @param {Number} level The tile level for which to get the maximum geometric error.
* @returns {Number} The maximum geometric error.
*/
EllipsoidTerrainProvider.prototype.getLevelMaximumGeometricError = function(level) {
return this._levelZeroMaximumGeometricError / (1 << level);
};
/**
* Determines whether data for a tile is available to be loaded.
*
* @param {Number} x The X coordinate of the tile for which to request geometry.
* @param {Number} y The Y coordinate of the tile for which to request geometry.
* @param {Number} level The level of the tile for which to request geometry.
* @returns {Boolean} Undefined if not supported, otherwise true or false.
*/
EllipsoidTerrainProvider.prototype.getTileDataAvailable = function(x, y, level) {
return undefined;
};
return EllipsoidTerrainProvider;
});