/// <summary>Begins a threaded prune of the particles</summary>
/// <param name="pruneDelegate">
/// Method that evaluates whether a particle should be pruned from the system
/// </param>
/// <param name="callback">
/// Callback that will be invoked when the update has finished
/// </param>
/// <param name="state">
/// User defined parameter that will be passed to the callback
/// </param>
/// <returns>An asynchronous result handle for the background operation</returns>
public IAsyncResult BeginPrune(
PrunePredicate pruneDelegate, AsyncCallback callback, object state
)
{
Debug.Assert(
!this.asyncPrune.IsRunning, "An asynchronous prune is already running"
);
Debug.Assert(
!this.asyncUpdate.IsRunning, "Can't prune while an asynchronous update is running"
);
this.asyncPrune.Start(pruneDelegate, callback, state);
return(this.asyncPrune);
}
/// <summary>Prunes dead particles from the system</summary>
/// <param name="pruneDelegate">
/// Delegate deciding which particles will be pruned
/// </param>
public void Prune(PrunePredicate pruneDelegate)
{
for (int index = 0; index < this.particleCount;)
{
bool keep = pruneDelegate(ref this.particles[index]);
if (keep)
{
++index;
}
else
{
this.particles[index] = this.particles[this.particleCount - 1];
--this.particleCount;
}
}
}
/// <summary>
/// Resets the asynchronous prune process for another use
/// </summary>
/// <param name="pruneDelegate">Method deciding which particles to prune</param>
/// <param name="callback">
/// Callback that will be invoked when pruning has finished
/// </param>
/// <param name="state">User-defined state from the BeginPrune() method</param>
public void Start(
PrunePredicate pruneDelegate, AsyncCallback callback, object state
)
{
this.running = true;
lock (this) {
this.completed = false;
if (this.doneEvent != null)
{
this.doneEvent.Reset();
}
}
this.exception = null;
this.pruneDelegate = pruneDelegate;
this.callback = callback;
this.state = state;
ThreadPool.QueueUserWorkItem(this.runDelegate);
}
