C#游戏开发中精确的时间调配

方法一：参考《精通C#游戏编程》一书。根据学习WorldWind源码可知，WorldWind中采用的方法与该方法基本一致。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;

namespace GameLoop//根据需要修改名称空间
{
public class PreciseTimer
{
[System.Security.SuppressUnmanagedCodeSecurity]
[DllImport("kernel32")]
private static extern bool QueryPerformanceFrequency(ref long PerformanceFrequency);

[System.Security.SuppressUnmanagedCodeSecurity]
[DllImport("kernel32")]
private static extern bool QueryPerformanceCounter(ref long PerformanceCount);

long _ticksPerSecond = 0;
long _previousElapsedTime = 0;

public PreciseTimer()
{
QueryPerformanceFrequency(ref _ticksPerSecond);
GetElapsedTime(); // Get rid of first rubbish result
}

public double GetElapsedTime()
{
long time = 0;
QueryPerformanceCounter(ref time);

double elapsedTime = (double)(time - _previousElapsedTime) / (double)_ticksPerSecond;
_previousElapsedTime = time;

return elapsedTime;
}
}
}