/// <summary>
/// Finds the "best" tile from queue
/// </summary>
public virtual GeoSpatialDownloadRequest GetClosestDownloadRequest()
{
GeoSpatialDownloadRequest closestRequest = null;
GeoSpatialDownloadRequest firstRequest = null;
double largestArea = double.MinValue;
lock (m_downloadRequests.SyncRoot)
{
foreach (GeoSpatialDownloadRequest curRequest in m_downloadRequests.Values)
{
if (curRequest.IsDownloading)
{
continue;
}
BoundingBox bb = new BoundingBox((float)curRequest.Boundary.South,
(float)curRequest.Boundary.North,
(float)curRequest.Boundary.West,
(float)curRequest.Boundary.East,
(float)m_camera.WorldRadius,
(float)m_camera.WorldRadius + 300000f);
if (!m_camera.ViewFrustum.Intersects(bb))
{
deletionList.Add(curRequest);
continue;
}
double screenArea = bb.CalcRelativeScreenArea(m_camera);
if (screenArea > largestArea)
{
largestArea = screenArea;
closestRequest = curRequest;
}
if (firstRequest != null)
{
firstRequest = curRequest;
}
}
}
// Remove requests that point to invisible tiles
foreach (GeoSpatialDownloadRequest req in deletionList)
{
m_downloadRequests.Remove(req.ToString());
//if (req.QuadTile != null)
// req.QuadTile.DownloadRequest = null;
}
deletionList.Clear();
if (closestRequest == null && firstRequest != null)
{
closestRequest = firstRequest;
}
return(closestRequest);
}