Tile improved

I have just improved tile images when its source are a WMS sever. Now, when the camera advances to the globe (and depending on its altitude) the set of tiles that composes the globe becomes more populated and with more detail (every tile queries for a more little piece of earth).
The next image show this. The left window shows all the globe with the Blue Marble images composed by 4x4 set of tiles. In the right window a zoom has made centered in Catalonia (Catalunya, where i live :) ).



Also note that the loading process doesn't use the brute force. Tiles that are hidden doesn't query the server for images, that is, only when a TileImage must to be rendered for the first time, it queries the server (or an image file, this depends on a Loader class) for the texture data.