fps.cpp

本程序表现了一个草地在天空飞行的情景本程序是系列程序的第四步。

#include "FPS.h"

FPS_CLASS::FPS_CLASS()
{
   t1 = 0;
   tx = 0;
   t2 = timeGetTime();
   FPS = 0;
   tFPS = 0;
   Interval = 0.0f;
}

void FPS_CLASS::StartMath(int time)
{
   Ttime = time;
   MathTime = true;
}

DWORD FPS_CLASS::GetFps()
{
   t2 = timeGetTime();
   T2 = t2;

   if (Interval > 0.0f)
   {
        if (tx == 0) tx = t2;
        if ((t2 - tx) > (DWORD)Interval)
        {
                IsOneSecond = true;
                Interval = 0.0f;
                tx = 0;
        }else
        {
                IsOneSecond = false;
        }
   }

   if ((t2 - t1)/1000 > 1)
   {
           if (MathTime)
           {
               Ttime--;
               if (Ttime < 1)
               {
                   Ttime = 0;
                }
           }

           t1 = t2;
	   FPS = tFPS;
	   tFPS = 0;
   }else
   {
	   tFPS++;
   }

   ultoa(FPS,fpsString,16);

   return FPS;
}