/// <summary>
/// Marks this Clock as the root of a timing tree.
/// </summary>
/// <param name="timeManager">
/// The TimeManager that controls this timing tree.
/// </param>
internal void MakeRoot(TimeManager timeManager)
{
Debug.Assert(!IsTimeManager, "Cannot associate a root with multiple timing trees");
Debug.Assert(this._timeManager == null, "Cannot use a timeline already in the timing tree as a root");
Debug.Assert(timeManager.TimeManagerClock == this, "Cannot associate more than one root per timing tree");
Debug.Assert(this._parent == null && _children == null, "Cannot use a timeline connected to other timelines as a root");
IsTimeManager = true;
_rootChildren = new List<WeakReference>();
_timeManager = timeManager;
_depth = 0;
//
InternalCurrentIteration = 1;
InternalCurrentProgress = 0;
InternalCurrentGlobalSpeed = 1;
InternalCurrentClockState = ClockState.Active;
}
/// <summary>
/// The MediaContext lives in the Dispatcher and is the MediaSystem's class that keeps
/// per Dispatcher state.
/// </summary>
internal MediaContext(Dispatcher dispatcher)
{
// We create exactly one MediaContext per thread. This is the one
// for this thread
Debug.Assert(dispatcher.Reserved0 == null);
// Initialize frame time information
if (IsClockSupported)
{
SafeNativeMethods.QueryPerformanceCounter(out _lastPresentationTime);
_estimatedNextPresentationTime = TimeSpan.FromTicks(CountsToTicks(_lastPresentationTime));
}
// Generate a unique id for our context so that we can pass this along to
// CreateHWNDRenderTarget
_contextGuid = Guid.NewGuid();
// Create a dictionary in which we manage the CompositionTargets.
_registeredICompositionTargets = new Dictionary<ICompositionTarget, object>();
_renderModeMessage = new DispatcherOperationCallback(InvalidateRenderMode);
// Create a notification window to listen for broadcast window messages
_notificationWindow = new MediaContextNotificationWindow(this);
// Connect to the MediaSystem.
if (MediaSystem.Startup(this))
{
_isConnected = MediaSystem.ConnectChannels(this);
}
// Subscribe to the OnDestroyContext event so that we can cleanup our state.
_destroyHandler = new EventHandler(this.OnDestroyContext);
Dispatcher.ShutdownFinished += _destroyHandler;
_renderMessage = new DispatcherOperationCallback(RenderMessageHandler);
_animRenderMessage = new DispatcherOperationCallback(AnimatedRenderMessageHandler);
_inputMarkerMessage = new DispatcherOperationCallback(InputMarkerMessageHandler);
// We hold off connecting ourselves to the dispatcher until we are sure that
// initialization will complete successfully. In rare cases, function calls
// earlier in this constructor throw exceptions, resulting in the MediaContext
// being left in an uninitialized state; however, the Dispatcher could call methods
// on the MediaContext, resulting in unpredictable behaviour (see bug 1630647).
//
// NOTE: We must attach to the Dispatcher before creating a TimeManager,
// otherwise we will create a circular function loop where TimeManager attempts
// to create a Clock, which attempts to locate a MediaContext, which attempts to
// create a TimeManager, resulting in a stack overflow.
dispatcher.Reserved0 = this;
_timeManager = new TimeManager();
_timeManager.Start();
_timeManager.NeedTickSooner += new EventHandler(OnNeedTickSooner);
_promoteRenderOpToInput = new DispatcherTimer(DispatcherPriority.Render);
_promoteRenderOpToInput.Tick += new EventHandler(PromoteRenderOpToInput);
_promoteRenderOpToRender = new DispatcherTimer(DispatcherPriority.Render);
_promoteRenderOpToRender.Tick += new EventHandler(PromoteRenderOpToRender);
_estimatedNextVSyncTimer = new DispatcherTimer(DispatcherPriority.Render);
_estimatedNextVSyncTimer.Tick += new EventHandler(EstimatedNextVSyncTimeExpired);
_commitPendingAfterRender = false;
}
