/*global define*/
define([
'../Core/defined',
'./ImageryState'
], function(
defined,
ImageryState) {
'use strict';
/**
* The assocation between a terrain tile and an imagery tile.
*
* @alias TileImagery
* @private
*
* @param {Imagery} imagery The imagery tile.
* @param {Cartesian4} textureCoordinateRectangle The texture rectangle of the tile that is covered
* by the imagery, where X=west, Y=south, Z=east, W=north.
* @param {Boolean} useWebMercatorT true to use the Web Mercator texture coordinates for this imagery tile.
*/
function TileImagery(imagery, textureCoordinateRectangle, useWebMercatorT) {
this.readyImagery = undefined;
this.loadingImagery = imagery;
this.textureCoordinateRectangle = textureCoordinateRectangle;
this.textureTranslationAndScale = undefined;
this.useWebMercatorT = useWebMercatorT;
}
/**
* Frees the resources held by this instance.
*/
TileImagery.prototype.freeResources = function() {
if (defined(this.readyImagery)) {
this.readyImagery.releaseReference();
}
if (defined(this.loadingImagery)) {
this.loadingImagery.releaseReference();
}
};
/**
* Processes the load state machine for this instance.
*
* @param {Tile} tile The tile to which this instance belongs.
* @param {FrameState} frameState The frameState.
* @returns {Boolean} True if this instance is done loading; otherwise, false.
*/
TileImagery.prototype.processStateMachine = function(tile, frameState) {
var loadingImagery = this.loadingImagery;
var imageryLayer = loadingImagery.imageryLayer;
loadingImagery.processStateMachine(frameState, !this.useWebMercatorT);
if (loadingImagery.state === ImageryState.READY) {
if (defined(this.readyImagery)) {
this.readyImagery.releaseReference();
}
this.readyImagery = this.loadingImagery;
this.loadingImagery = undefined;
this.textureTranslationAndScale = imageryLayer._calculateTextureTranslationAndScale(tile, this);
return true; // done loading
}
// Find some ancestor imagery we can use while this imagery is still loading.
var ancestor = loadingImagery.parent;
var closestAncestorThatNeedsLoading;
while (defined(ancestor) && ancestor.state !== ImageryState.READY) {
if (ancestor.state !== ImageryState.FAILED && ancestor.state !== ImageryState.INVALID) {
// ancestor is still loading
closestAncestorThatNeedsLoading = closestAncestorThatNeedsLoading || ancestor;
}
ancestor = ancestor.parent;
}
if (this.readyImagery !== ancestor) {
if (defined(this.readyImagery)) {
this.readyImagery.releaseReference();
}
this.readyImagery = ancestor;
if (defined(ancestor)) {
ancestor.addReference();
this.textureTranslationAndScale = imageryLayer._calculateTextureTranslationAndScale(tile, this);
}
}
if (loadingImagery.state === ImageryState.FAILED || loadingImagery.state === ImageryState.INVALID) {
// The imagery tile is failed or invalid, so we'd like to use an ancestor instead.
if (defined(closestAncestorThatNeedsLoading)) {
// Push the ancestor's load process along a bit. This is necessary because some ancestor imagery
// tiles may not be attached directly to a terrain tile. Such tiles will never load if
// we don't do it here.
closestAncestorThatNeedsLoading.processStateMachine(frameState, !this.useWebMercatorT);
return false; // not done loading
} else {
// This imagery tile is failed or invalid, and we have the "best available" substitute.
return true; // done loading
}
}
return false; // not done loading
};
return TileImagery;
});