// created on 07/13/2005 at 17:06

using System;
using System.Runtime.InteropServices;
using System.ComponentModel;
using System.Threading;

public class GameTimer{

    //Import the APIs we need.
	[DllImport("Kernel32.dll")]
	private static extern bool QueryPerformanceCounter(out long lpPerformanceCount);
	[DllImport("Kernel32.dll")]
	private static extern bool QueryPerformanceFrequency(out long lpFrequency);

	public long last;
	public long now;
	private long freq;


	// Constructor
	public GameTimer(){
		if (QueryPerformanceFrequency(out freq) == false){
			throw new Win32Exception(); // timer not supported
		}else{
			QueryPerformanceCounter(out last);
			QueryPerformanceCounter(out now);
		}
	}
 
	// Restarts the timer (starts timing from now).
	public void Mark(){
        QueryPerformanceCounter(out last);
	}

	// Return the time since last Mark().
	public double GetElapsedTime(){
		QueryPerformanceCounter(out now);
		return ((double)(now - last) / (double)freq);
	}
}