/// <summary>
/// Load tile either from local cache or from web (in this case, send an asynchronous request that will be received later)
/// Returns true if load happened (either from cache or from web), returns false if it didn't (because too many requests are pending)
/// </summary>
/// <param name="zoom"></param>
/// <param name="coordX"></param>
/// <param name="coordY"></param>
/// <returns></returns>
public bool LoadTileImageFromZoomAndCoords(int zoom, int coordX, int coordY)
{
string key = MapGeneratorOSM.GetKeyFromZoomAndCoords(zoom, coordX, coordY);
string tilePath = GetTilePathFromZoomAndCoords(zoom, coordX, coordY);
if (!allTileTexturesFilePathDico.ContainsKey(key))
{
// We don't know tile path, it means we never created the file nor made a request to download it
bool fileExists = false;
lock (fileAccessLock)
{
fileExists = File.Exists(tilePath);
if (fileExists)
{
// check if file really contains something (never too careful)
FileInfo info = new FileInfo(tilePath);
if (info.Length <= 0)
{
// file exist but is empty
fileExists = false;
}
}
}
if (fileExists)
{
// but it already exists in cache ! So we should just ask for rendering
mapGenerator.EnqueueTileToDisplay(key);
}
else
{
// it doesn't exist yet, so we should create it and download its content
CreateTileDirectoriesIfNeeded(zoom, coordX);
// except if there are too many requests pending
if (webRequestCount >= webRequestMaxCount)
{
//Debug.LogWarning("Prevent download of tile : " + key + " because webRequestCount is = " + webRequestCount);
return(false);
}
allTileTexturesFilePathDico.Add(key, tilePath);
// Call web request to download image
lock (fileAccessLock)
{
try
{
string url = RandomServer() + "/" + zoom + "/" + coordX + "/" + coordY + ".png";
//Debug.Log(url);
WebClient client = new WebClient();
// sync
//client.DownloadFile(new Uri(url), tilePath);
// async
client.DownloadFileCompleted += new AsyncCompletedEventHandler(DownloadDataCallback);
client.DownloadFileAsync(new Uri(url), tilePath, key);
webRequestCount++;
}
catch (System.Exception ex)
{
Debug.LogError("LoadTileImageFromZoomAndCoords got exception : " + ex.Message);
}
}
}
}
return(true);
}
