/// <summary>
/// Updates the specified context.
/// </summary>
/// <param name="uv">The Ultraviolet context to update.</param>
/// <param name="time">Time elapsed since the last update.</param>
/// <returns><see langword="true"/> if the host should continue processing; otherwise, <see langword="false"/>.</returns>
private Boolean UpdateContext(UltravioletContext uv, UltravioletTime time)
{
using (UltravioletProfiler.Section(UltravioletProfilerSections.Update))
{
uv.Update(time);
}
return(!uv.Disposed);
}
/// <summary>
/// Advances the application state by one tick.
/// </summary>
public void RunOneTick()
{
var uv = host.Ultraviolet;
if (!host.IsActive && InactiveSleepTime.TotalMilliseconds > 0)
{
Thread.Sleep(InactiveSleepTime);
}
var syncContext = SynchronizationContext.Current as UltravioletSynchronizationContext;
if (syncContext != null)
{
syncContext.ProcessWorkItems();
}
if (IsFixedTimeStep)
{
if (tickTimer.Elapsed.TotalMilliseconds >= targetElapsedTime.TotalMilliseconds)
{
tickTimer.Restart();
tickElapsed -= targetElapsedTime.TotalMilliseconds * (int)(tickElapsed / targetElapsedTime.TotalMilliseconds);
uv.HandleFrameStart();
const Double CatchUpThreshold = 1.05;
if (frameElapsed > 0 && frameElapsed > targetElapsedTime.TotalMilliseconds * CatchUpThreshold)
{
const Int32 RunningSlowlyFrameCount = 5;
runningSlowlyFrames = RunningSlowlyFrameCount;
isRunningSlowly = true;
const Int32 CatchUpFrameLimit = 10;
var catchUpUpdates = Math.Min(CatchUpFrameLimit, (int)(frameElapsed / targetElapsedTime.TotalMilliseconds));
for (int i = 0; i < catchUpUpdates; i++)
{
timeTrackerUpdate.Increment(targetElapsedTime, isRunningSlowly);
timeTrackerDraw.Increment(targetElapsedTime, isRunningSlowly);
if (!UpdateContext(uv, timeTrackerUpdate.Time))
{
return;
}
}
}
else
{
if (isRunningSlowly)
{
runningSlowlyFrames--;
if (runningSlowlyFrames == 0)
{
isRunningSlowly = false;
}
}
}
frameTimer.Restart();
var uvTimeUpdate = timeTrackerUpdate.Increment(targetElapsedTime, isRunningSlowly);
if (!UpdateContext(uv, uvTimeUpdate))
{
return;
}
if (!host.IsSuspended)
{
var uvTimeDraw = timeTrackerDraw.Increment(targetElapsedTime, isRunningSlowly);
using (UltravioletProfiler.Section(UltravioletProfilerSections.Draw))
{
uv.Draw(uvTimeDraw);
}
}
uv.HandleFrameEnd();
frameElapsed = frameTimer.Elapsed.TotalMilliseconds;
}
else
{
// NOTE: The precision of Sleep() can generally be assumed to be something like 10-15ms, so
// we only call it if we know we're going to be waiting a long time and there's no point
// in sucking up CPU cycles spinning our loop.
var frameDelay = (int)(targetElapsedTime.TotalMilliseconds - tickTimer.Elapsed.TotalMilliseconds);
if (frameDelay >= 10)
{
Thread.Sleep(frameDelay);
}
}
}
else
{
var time = tickTimer.Elapsed.TotalMilliseconds;
tickTimer.Restart();
uv.HandleFrameStart();
var uvTimeDelta = TimeSpan.FromTicks((long)(time * TimeSpan.TicksPerMillisecond));
var uvTimeUpdate = timeTrackerUpdate.Increment(uvTimeDelta, false);
if (!UpdateContext(uv, uvTimeUpdate))
{
return;
}
if (!host.IsSuspended)
{
var uvTimeDraw = uvTimeUpdate;
using (UltravioletProfiler.Section(UltravioletProfilerSections.Draw))
{
uv.Draw(uvTimeDraw);
}
}
uv.HandleFrameEnd();
}
}