当我使用 XNA 框架(适用于 windows Phone)时,我的游戏运行良好,但是当我在 Silverlight/XNA 框架上迁移时,我遇到了动画滞后的问题。问题如下:当我将固定时间步设置为 GameTimer (timer.UpdateInterval = TimeSpan.FromTicks(333333)) 时,实际时间步不固定,并且计时器事件(OnUpdate、OnDraw)以不同的间隔触发。这段代码更清楚地显示了我的问题:
Silverlight/XNA 框架:(动画滞后):
TimeSpan curNow;
TimeSpan lastUpdate;
TimeSpan lastDraw;
public GamePage()
{
timer = new GameTimer();
timer.UpdateInterval = TimeSpan.FromTicks(333333);
timer.Update += OnUpdate;
timer.Draw += OnDraw;
}
private void OnUpdate(object sender, GameTimerEventArgs e)
{
curNow = new TimeSpan(DateTime.Now.Ticks);
TimeSpan elapsed=e.ElapsedTime;//Always constant and has value: 33ms
TimeSpan realElapsed = curNow - lastUpdate;//Real elapsed time always changing and has a value between: 17-39ms (sometimes more then 39ms)
lastUpdate = curNow;
}
private void OnDraw(object sender, GameTimerEventArgs e)
{
curNow = new TimeSpan(DateTime.Now.Ticks);
TimeSpan elapsed=e.ElapsedTime;//Always changing and has a value between: 17-39ms (sometimes more then 39ms)
TimeSpan realElapsed = curNow -lastDraw;//Always changing and has a value between: 17-39ms (sometimes more then 39ms)
lastDraw= curNow;
}
XNA 框架:(一切正常):
TimeSpan curNow;
TimeSpan lastUpdate;
TimeSpan lastDraw;
public Game()
{
// Frame rate is 30 fps by default for Windows Phone.
TargetElapsedTime = TimeSpan.FromTicks(333333);
}
protected override void Update(GameTime gameTime)
{
curNow = new TimeSpan(DateTime.Now.Ticks);
TimeSpan elapsed=gameTime.ElapsedGameTime;//Always constant and has value: 33ms
TimeSpan realElapsed = curNow - lastUpdate;//Real elapsed time has a value between: 34-35ms (sometimes more then 35ms)
lastUpdate = curNow;
}
protected override void Draw(GameTime gameTime)
{
curNow = new TimeSpan(DateTime.Now.Ticks);
TimeSpan elapsed=gameTime.ElapsedGameTime ;//Value between: 33-34ms (sometimes more then 34ms)
TimeSpan realElapsed = curNow - lastDraw;//Value between: 34-35ms (sometimes more then 35ms)
lastDraw = curNow;
}