private void SetEngagedUserTrackingId(int newId, EventQueueSection section)
{
int oldId = this.EngagedUserTrackingId;
this.EngagedUserTrackingId = newId;
if (oldId != newId)
{
section.Enqueue(
() =>
{
if (this.EngagedUserChanged != null)
{
var args = new UserTrackingIdChangedEventArgs(oldId, newId);
this.EngagedUserChanged(this, args);
}
});
}
}
private void SendTrackedUsersChanged(EventQueueSection section)
{
section.Enqueue(
() =>
{
if (this.TrackedUsersChanged != null)
{
this.TrackedUsersChanged(this, EventArgs.Empty);
}
});
}
internal void SetPrimaryUserTrackingId(int newId, EventQueueSection section)
{
int oldId = this.PrimaryUserTrackingId;
this.PrimaryUserTrackingId = newId;
if (oldId != newId)
{
section.Enqueue(
() =>
{
if (this.PrimaryUserChanged != null)
{
var args = new UserTrackingIdChangedEventArgs(oldId, newId);
this.PrimaryUserChanged(this, args);
}
});
// If the new primary user is the same as the engaged user, then there is no candidate user.
// Otherwise, we have a new candidate user as long as the new primary user is a valid user.
this.SetCandidateUserTrackingId(
(this.EngagedUserTrackingId != InvalidUserTrackingId) && (this.EngagedUserTrackingId == newId)
? InvalidUserTrackingId
: newId,
section);
}
}
/// <summary>
/// Called whenever the set of tracked hand pointers has changed.
/// </summary>
/// <param name="trackedHandPointers">
/// Hand pointers from which we'll update the set of tracked users and the primary user.
/// </param>
public void UpdateHandPointers(IEnumerable<HandPointer> trackedHandPointers)
{
bool foundEngagedUser = false;
bool foundCandidateUser = false;
int primaryUserTrackingId = InvalidUserTrackingId;
using (var section = new EventQueueSection())
{
this.TrackedUserTrackingIds.Clear();
foreach (var handPointer in trackedHandPointers)
{
if (handPointer.IsTracked && (handPointer.TrackingId != InvalidUserTrackingId))
{
// Only consider valid user tracking ids
this.TrackedUserTrackingIds.Add(handPointer.TrackingId);
if (this.EngagedUserTrackingId == handPointer.TrackingId)
{
foundEngagedUser = true;
}
if (this.CandidateUserTrackingId == handPointer.TrackingId)
{
foundCandidateUser = true;
}
if (handPointer.IsPrimaryUser)
{
primaryUserTrackingId = handPointer.TrackingId;
}
}
}
this.SendTrackedUsersChanged(section);
// If engaged user was not found in list of candidate users, engaged user has become invalid.
if (!foundEngagedUser)
{
this.SetEngagedUserTrackingId(InvalidUserTrackingId, section);
}
// If candidate user was not found in list of candidate users, candidate user has become invalid.
if (!foundCandidateUser)
{
this.SetCandidateUserTrackingId(InvalidUserTrackingId, section);
}
this.SetPrimaryUserTrackingId(primaryUserTrackingId, section);
}
}
/// <summary>
/// Resets all state to the initial state, with no users remembered as engaged or tracked.
/// </summary>
public void Reset()
{
using (var section = new EventQueueSection())
{
this.activityMeter.Clear();
this.TrackedUserTrackingIds.Clear();
this.PrimaryUserTrackingId = InvalidUserTrackingId;
this.SetCandidateUserTrackingId(InvalidUserTrackingId, section);
this.SetEngagedUserTrackingId(InvalidUserTrackingId, section);
this.SendTrackedUsersChanged(section);
}
}
/// <summary>
/// Promote candidate user to be the engaged user.
/// </summary>
/// <param name="candidateTrackingId">
/// Tracking Id of user to be promoted to engaged user.
/// If tracking Id does not match the Id of current candidate user,
/// no action is taken.
/// </param>
/// <returns>
/// True if specified candidate could be confirmed as the new engaged user,
/// false otherwise.
/// </returns>
public bool ConfirmCandidateEngagement(int candidateTrackingId)
{
bool isConfirmed = false;
if ((candidateTrackingId != InvalidUserTrackingId) && (candidateTrackingId == this.CandidateUserTrackingId))
{
using (var section = new EventQueueSection())
{
this.SetCandidateUserTrackingId(InvalidUserTrackingId, section);
this.SetEngagedUserTrackingId(candidateTrackingId, section);
}
isConfirmed = true;
}
return isConfirmed;
}
