// update for given elapsed time
public void Update(float elapsedTime)
{
// if in a transition
if (fade > 0)
{
// update transition time
fade -= elapsedTime;
// if time to switch to new screen (fade out finished)
if (next != null && fade < 0.5f * fadeTime)
{
// tell new screen it is getting in focus
next.SetFocus(contentManager, true);
// tell the old screen it lost its focus
if (current != null)
{
current.SetFocus(contentManager, false);
}
// set new screen as current
current = next;
next = null;
}
}
// if current screen available, update it
if (current != null)
{
current.Update(elapsedTime);
}
// calulate frame rate
frameRateTime += elapsedTime;
if (frameRateTime > 0.5f)
{
frameRate = (int)((float)frameRateCount / frameRateTime);
frameRateCount = 0;
frameRateTime = 0;
}
// accumulate elapsed time for background animation
backgroundTime += elapsedTime;
}
