80 lines
2.5 KiB
JavaScript
80 lines
2.5 KiB
JavaScript
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define([
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'../Core/defined',
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'../Core/DoublyLinkedList'
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], function(
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defined,
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DoublyLinkedList) {
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'use strict';
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/**
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* Stores tiles with content loaded.
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*
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* @private
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*/
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function Cesium3DTilesetCache() {
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// [head, sentinel) -> tiles that weren't selected this frame and may be removed from the cache
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// (sentinel, tail] -> tiles that were selected this frame
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this._list = new DoublyLinkedList();
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this._sentinel = this._list.add();
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this._trimTiles = false;
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}
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Cesium3DTilesetCache.prototype.reset = function() {
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// Move sentinel node to the tail so, at the start of the frame, all tiles
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// may be potentially replaced. Tiles are moved to the right of the sentinel
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// when they are selected so they will not be replaced.
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this._list.splice(this._list.tail, this._sentinel);
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};
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Cesium3DTilesetCache.prototype.touch = function(tile) {
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var node = tile.cacheNode;
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if (defined(node)) {
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this._list.splice(this._sentinel, node);
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}
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};
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Cesium3DTilesetCache.prototype.add = function(tile) {
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if (!defined(tile.cacheNode)) {
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tile.cacheNode = this._list.add(tile);
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}
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};
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Cesium3DTilesetCache.prototype.unloadTile = function(tileset, tile, unloadCallback) {
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var node = tile.cacheNode;
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if (!defined(node)) {
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return;
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}
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this._list.remove(node);
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tile.cacheNode = undefined;
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unloadCallback(tileset, tile);
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};
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Cesium3DTilesetCache.prototype.unloadTiles = function(tileset, unloadCallback) {
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var trimTiles = this._trimTiles;
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this._trimTiles = false;
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var list = this._list;
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var maximumMemoryUsageInBytes = tileset.maximumMemoryUsage * 1024 * 1024;
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// Traverse the list only to the sentinel since tiles/nodes to the
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// right of the sentinel were used this frame.
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//
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// The sub-list to the left of the sentinel is ordered from LRU to MRU.
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var sentinel = this._sentinel;
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var node = list.head;
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while ((node !== sentinel) && ((tileset.totalMemoryUsageInBytes > maximumMemoryUsageInBytes) || trimTiles)) {
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var tile = node.item;
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node = node.next;
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this.unloadTile(tileset, tile, unloadCallback);
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}
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};
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Cesium3DTilesetCache.prototype.trim = function() {
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this._trimTiles = true;
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};
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return Cesium3DTilesetCache;
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});
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