C# 实用赛车游戏计时器源代码

using System; 
using System.Runtime.InteropServices; 
 
namespace Dodger 
{ 
 
    /// <summary> 
    /// Enumeration for various actions our timer can perform 
    /// </summary> 
    public enum DirectXTimer 
    { 
        Reset,  
        Start,  
        Stop,  
        Advance, 
        GetAbsoluteTime,  
        GetApplicationTime,  
        GetElapsedTime  
    }; 
 
    /// <summary> 
/// Summary description for Utility. 
/// </summary> 
public class Utility 
{ 
        #region Timer Internal Stuff 
        [System.Security.SuppressUnmanagedCodeSecurity] // We won't use this maliciously 
        [DllImport("kernel32")] 
        private static extern bool QueryPerformanceFrequency(ref long PerformanceFrequency); 
        [System.Security.SuppressUnmanagedCodeSecurity] // We won't use this maliciously 

        [DllImport("kernel32")] 
        private static extern bool QueryPerformanceCounter(ref long PerformanceCount); 
        [System.Security.SuppressUnmanagedCodeSecurity] // We won't use this maliciously 
        [DllImport("winmm.dll")] 
        public static extern int timeGetTime(); 
        private static bool isTimerInitialized = false; 
        private static bool m_bUsingQPF = false; 
        private static bool m_bTimerStopped = true; 
        private static long m_llQPFTicksPerSec = 0; 
        private static long m_llStopTime = 0; 
        private static long m_llLastElapsedTime = 0; 
        private static long m_llBaseTime = 0; 
        private static double m_fLastElapsedTime = 0.0; 
        private static double m_fBaseTime = 0.0; 
        private static double m_fStopTime = 0.0; 
     #endregion 
 
        /// <summary> 
        /// Performs timer opertations. Use the following commands: 
        ///  
        ///          DirectXTimer.Reset - to reset the timer 
        ///          DirectXTimer.Start - to start the timer 
        ///          DirectXTimer.Stop - to stop (or pause) the timer 
        ///          DirectXTimer.Advance - to advance the timer by 0.1 seconds 
        ///          DirectXTimer.GetAbsoluteTime - to get the absolute system time 
        ///          DirectXTimer.GetApplicationTime - to get the current time 
        ///          DirectXTimer.GetElapsedTime - to get the time that elapsed between TIMER_GETELAPSEDTIME calls 
        /// 
        /// </summary> 
        public static float Timer(DirectXTimer command)