/// <summary>
/// Creates a new tile.
/// </summary>
/// <param name="producerId">the id of the producer of this tile.</param>
/// <param name="level">the quadtree level of this tile.</param>
/// <param name="tx">tx the quadtree x coordinate of this tile.</param>
/// <param name="ty">ty the quadtree y coordinate of this tile.</param>
/// <param name="task">task the task that will produce the tile data.</param>
public Tile(int producerId, int level, int tx, int ty, CreateTileTask task)
{
if (task == null)
{
throw new ArgumentNullException("task can not be null");
}
TId = new TId(producerId, level, tx, ty);
Users = 0;
m_task = task;
}
/// <summary>
/// Call this if a tile is needed. Will move the tile from the unused to the used cache if its is found there.
/// If the tile is not found then a new tile will be created with a new slot.If there are no more free
/// slots then the cache capacity has not been set to a high enough value and the program must abort.
/// </summary>
public Tile GetTile(int producerId, int level, int tx, int ty)
{
//If this producer id does not exist can not create tile.
if (!m_producers.ContainsKey(producerId))
{
throw new InvalidOperationException("Producer id not been inserted into cache");
}
TId id = new TId(producerId, level, tx, ty);
Tile tile = null;
//If tile is not in the used cache
if (!m_usedTiles.ContainsKey(id))
{
//If tile is also not in the unused cache
if (!m_unusedTiles.ContainsKey(id))
{
List <Slot> slot = NewSlot();
//if there are no more free slots then start recyling slots from the unused tiles
if (slot == null && !m_unusedTiles.Empty())
{
//Remove the tile and recylce its slot
slot = m_unusedTiles.RemoveFirst().Slot;
}
//If a slot is found create a new tile with a new task
if (slot != null)
{
CreateTileTask task = m_producers[producerId].CreateTask(level, tx, ty, slot);
tile = new Tile(producerId, level, tx, ty, task);
}
//If a free slot is not found then program has must abort. Try setting the cache capacity to higher value.
if (slot == null)
{
throw new CacheCapacityException("No more free slots found. Insufficient storage capacity for cache " + name);
}
}
else
{
//else if the tile is in the unused cache remove it and keep a reference to it
tile = m_unusedTiles.Remove(id);
}
if (tile != null)
{
m_usedTiles.Add(id, tile);
}
}
else
{
tile = m_usedTiles[id];
}
//Should never be null be this stage
if (tile == null)
{
throw new ArgumentNullException("Tile should not be null");
}
//Keep track of the max number of tiles ever used for debug purposes
if (m_usedTiles.Count > m_maxUsedTiles)
{
m_maxUsedTiles = m_usedTiles.Count;
}
//inc the num of users
tile.IncrementUsers();
return(tile);
}
