Use more a reliable time source in Windows for the Timer class

src/util/Timer.cpp

@@ -5,13 +5,18 @@
 
 #ifdef _WIN32
 	#include <windows.h>
-	#include <mmsystem.h>
 #endif
 
 #include <iostream>
 
 Timer::Timer(void) : time_elapsed(0), system_milliseconds(0), start_time(0), end_time(0), last_update(0), num_updates(0), paused_time(0), offset(0), paused_state(false), lock_state(false), lock_rate(0)
 {
+#ifdef _WIN32
+	// According to Microsoft, QueryPerformanceXXX API is perfectly
+	//fine for Windows 7+ systems, and use the highest appropriate counter.
+	//this only need to be done once.
+	::QueryPerformanceFrequency(&win_frequency);
+#endif;
 }
 
 
@@ -82,7 +87,12 @@ void Timer::update(void)
 	{
 #ifdef _WIN32
 
-		system_milliseconds = timeGetTime ();
+		//Use QuaryPerformanceCounter, imune to problems sometimes
+		//multimedia timers have.
+		LARGE_INTEGER win_current_count;
+		::QueryPerformanceCounter(&win_current_count);
+
+		system_milliseconds = (unsigned long)(win_current_count.QuadPart * 1000.0 / win_frequency.QuadPart);
 
 #else
 		gettimeofday(&time_val,&time_zone);

src/util/Timer.h

@@ -18,6 +18,7 @@
 class Timer {
 private:
 
+	//units are microsecs:
     unsigned long time_elapsed;
     unsigned long system_milliseconds;
     unsigned long start_time;
@@ -30,7 +31,9 @@ private:
 #ifndef _WIN32
     struct timeval time_val;
     struct timezone time_zone;
-#endif
+#else
+	LARGE_INTEGER win_frequency;
+#endif;
 
     bool paused_state;
     bool lock_state;
@@ -91,6 +94,7 @@ public:
      *  \return Total time elapsed since the timer start() to the last update() excluding time paused() in milliseconds
      */
     unsigned long getMilliseconds(void);
+
     /// Alias of getMilliseconds() which returns time in seconds
     /**
      *  \return Total time elapsed since the timer start() to the last update() excluding time paused() in seconds
@@ -159,6 +163,7 @@ public:
      */
     bool paused();
     
+
     
     void timerTestFunc();
 };