我正在使用 xna 为 Windows Phone 7 开发我的第一款游戏。经过一些测试后，我注意到游戏动画出现了短暂的减速并进行了一些性能测试，但无法完全消除减速。现在我创建了一个空项目，其中只有一个 DrawableGameComponent 继承类绘制有关 runsslow 标志、Draw/Update 时间（传递给方法）以及垃圾收集器是否正在运行的文本。奇怪的是，即使使用这个极简代码，延迟似乎大约每 1 到 5 秒发生一次。延迟我指的是何时绘制而不是 33 毫秒 > 50 毫秒。有时甚至在这个简约项目中设置了 runsslow 标志。从我的实验来看，垃圾收集器似乎不是造成这种情况的主要原因，因为他执行的次数要少得多。
更新代码：
public override void Update(GameTime gameTime)
{
elapsedTime += gameTime.ElapsedGameTime;
timeSpanUpdate.Add(gameTime.ElapsedGameTime.TotalMilliseconds);
if (elapsedTime.TotalMilliseconds >= timeToElapseForVisualisation)
{
//update the values messured
elapsedTime -= TimeSpan.FromMilliseconds(timeToElapseForVisualisation);
//get the values we are interested in
double sum = 0;
maxUpdateTime = int.MinValue;
foreach (double val in timeSpanUpdate)
{
sum += val;
maxUpdateTime = (int)Math.Max(maxUpdateTime, val);
}
averageUpdateTime = (int)(sum / timeSpanUpdate.Count);
timeSpanUpdate.Clear();
sum = 0;
maxDrawTime = int.MinValue;
foreach (double val in timeSpanDraw)
{
sum += val;
maxDrawTime = (int)Math.Max(maxDrawTime, val);
}
averageDrawTime = (int)(sum / timeSpanDraw.Count);
timeSpanDraw.Clear();
}
if (gameTime.IsRunningSlowly)
{
runsSlow = true;
timeToShowRunsslowRemaining = timeToShow;
}
else if (timeToShowRunsslowRemaining > 0)
{
timeToShowRunsslowRemaining -= gameTime.ElapsedGameTime.TotalMilliseconds;
}
else
{
runsSlow = false;
}
}
抽奖代码：
//we use stringbuilders as strings passed to drawstring can induce the gc
private StringBuilder drawText = new StringBuilder("Draw max: ");
private StringBuilder updateText = new StringBuilder("Update max: ");
private StringBuilder runsslowYes = new StringBuilder("runsslow: yes");
private StringBuilder runsslowNo = new StringBuilder("runsslow: no");
public override void Draw(GameTime gameTime)
{
DateTime now = DateTime.Now;
timeSpanDraw.Add((now - lastDrawCall).TotalMilliseconds);
lastDrawCall = now;
drawText.Remove("Draw max: ".Length, drawText.Length - "Draw max: ".Length);
drawText.Append(maxDrawTime);
updateText.Remove("Update max: ".Length, updateText.Length - "Update max: ".Length);
updateText.Append(maxUpdateTime);
spriteBatch.Begin();
if (maxDrawTime >= thresholdMaxDelays)
{
spriteBatch.DrawString(spriteFont, drawText, drawTextPos, Color.Red);
}
else
{
spriteBatch.DrawString(spriteFont, drawText, drawTextPos, Color.White);
}
if (maxUpdateTime >= thresholdMaxDelays)
{
spriteBatch.DrawString(spriteFont, updateText, updateTextPos, Color.Red);
}
else
{
spriteBatch.DrawString(spriteFont, updateText, updateTextPos, Color.White);
}
if (runsSlow)
{
spriteBatch.DrawString(spriteFont, runsslowYes, runsslowTextPos, Color.Red);
}
else
{
spriteBatch.DrawString(spriteFont, runsslowNo, runsslowTextPos, Color.White);
}
spriteBatch.End();
base.Draw(gameTime);
}
我还注意到它并非一直都在发生。