/// <summary>
/// Update the position of a monitor.
/// </summary>
/// <param name="monitor">The monitor whose position has changed.</param>
/// <param name="previousRegion">The previous area that the monitor was watching.</param>
/// <param name="currentRegion">The new area that the monitor is watching.</param>
public void UpdateMonitor(IQuadTreeMonitor <TItem> monitor, Bound previousRegion, Bound currentRegion)
{
// convert the bounds to rectangles
Rect previousRect = new Rect(previousRegion);
Rect currentRect = new Rect(currentRegion);
Rect merged = Rect.Merge(previousRect, currentRect);
IterateChunks(merged, node => {
bool previousContains = previousRect.Colliding(node.MonitoredRegion);
bool currentContains = currentRect.Colliding(node.MonitoredRegion);
// the monitor is no longer interested in this chunk
if (previousContains && currentContains == false)
{
node.Remove(monitor, previousRegion);
}
// the monitor is still interested in this chunk
else if (previousContains && currentContains)
{
node.Update(monitor, previousRegion, currentRegion);
}
// the monitor is now interested in this chunk, but was not before
else if (previousContains == false && currentContains)
{
node.Add(monitor, currentRegion);
}
});
}
public void Update(IQuadTreeMonitor <T> monitor, Bound previousRegion, Bound currentRegion)
{
// update the stored monitor
for (int i = 0; i < _monitors.Length; ++i)
{
if (ReferenceEquals(_monitors[i].Monitor, monitor))
{
_monitors[i].Region = currentRegion;
break;
}
}
// update the monitor
for (int i = 0; i < _items.Length; ++i)
{
StoredItem item = _items[i];
bool containedPrevious = previousRegion.Contains(item.Position);
bool containedCurrent = currentRegion.Contains(item.Position);
// the monitor was previously interested but no longer is
if (containedPrevious && containedCurrent == false)
{
monitor.OnExit(item.Item);
}
// the monitor was not previous interested but now is
else if (containedPrevious == false && containedCurrent)
{
monitor.OnEnter(item.Item);
}
}
}
public void Add(IQuadTreeMonitor <T> monitor, Bound monitoredRegion)
{
_monitors.Add(new StoredMonitor(monitor, monitoredRegion));
// check to see if the monitor is interested in any of our stored items
for (int i = 0; i < _items.Length; ++i)
{
StoredItem item = _items[i];
if (monitoredRegion.Contains(item.Position))
{
monitor.OnEnter(item.Item);
}
}
}
public void Remove(IQuadTreeMonitor <T> monitor, Bound monitoredRegion)
{
// remove the stored monitor
for (int i = 0; i < _monitors.Length; ++i)
{
if (ReferenceEquals(_monitors[i].Monitor, monitor))
{
_monitors.Remove(i);
break;
}
}
// remove all stored items from the monitor
for (int i = 0; i < _items.Length; ++i)
{
StoredItem item = _items[i];
if (monitoredRegion.Contains(item.Position))
{
monitor.OnExit(item.Item);
}
}
}
/// <summary>
/// Removes the given monitor from the quad tree. It will receive a series of OnExit calls
/// during this Remove call.
/// </summary>
/// <param name="monitor">The monitor to remove.</param>
/// <param name="monitoredRegion">The region that the monitor was monitoring.</param>
public void RemoveMonitor(IQuadTreeMonitor <TItem> monitor, Bound monitoredRegion)
{
IterateChunks(monitoredRegion, node => {
node.Remove(monitor, monitoredRegion);
});
}
public StoredMonitor(IQuadTreeMonitor <T> monitor, Bound region)
{
Monitor = monitor;
Region = region;
}
