// Save the screen shot
  if(!screenShotSaved && KEY_DOWN(VK_SNAPSHOT))
  {
     D3DDISPLAYMODE display;
     d3ddev->GetDisplayMode(0, &display);

     // Create the off screen surface with the same info as the back buffer
     d3ddev->CreateOffscreenPlainSurface(display.Width, display.Height, D3DFMT_A8R8G8B8, D3DPOOL_DEFAULT, 
										 &ScreenShotSurface, NULL);

     // Save the back buffer to the surface
     d3ddev->GetBackBuffer(0, 0, D3DBACKBUFFER_TYPE_MONO, &ScreenShotSurface);
     sprintf_s(screenshotdir,"Screenshots/Screenshot%d.png",i);
     D3DXSaveSurfaceToFile(screenshotdir, D3DXIFF_PNG, ScreenShotSurface, NULL, NULL);
     // Increase i for next screenshot (Only allow up to 10 screenshots max for memory safety)
    if(i>=10)
      i = 1;
    else
      i++;

    screenShotSaved = true;
  }

    if(ScreenShotSurface != NULL)    {         ScreenShotSurface->Release();         ScreenShotSurface = NULL;    }

// Gets and displays the Frames Per Secondvoid GetFPS(){   // Hold the number of frames per second in between seconds   static float FPS = 0.0f;   // Check if a second has passed   float nextSecond = 0.0f;   // Last second that occured   static float prevSecond = 0.0f;   // Add to the frames per second every time this function is called   FPS++;   // Get the second in millisecond then convert to seconds (by multiplying 0.001)   nextSecond = GetTickCount() * 0.001f;				   // If the time we have now substracted from the previous second is greater than   // or equal to 1 (i.e. if a second has passed) then we display the FPS number   if(nextSecond - prevSecond > 1.0f)      {         // Make the second we just got the previous second for next time the function is called	     prevSecond = nextSecond;		            // Display the FPS		 sprintf_s(frames,"FPS: %d",int(FPS));         // Reset the FPS counter         FPS = 0;      }}//End GetFPS

//============================================================================// PTimer.h - Timer class//============================================================================#ifndef __PTIMER_H__#define __PTIMER_H__#include <windows.h>class PTimer{public:	PTimer();	~PTimer();	// Get the time taken for the last frame in ms	float GetFrameTime() const { return m_fFrameTime; }	//========================================================================	void BeginFrame();	void EndFrame();protected:	float m_fFrameTime;	DWORD m_dwStartTime;	size_t m_nIndex;	bool m_bFirstLoop;	LARGE_INTEGER m_liFreq;	LARGE_INTEGER m_liStart;	static const size_t ms_nFramesAverage = 16;	float m_fFrameTimes[ms_nFramesAverage];};#endif // __PTIMER_H__

//============================================================================// PTimer.cpp - Timer class//============================================================================#include "PTimer.h"#include <mmsystem.h>#pragma comment(lib, "winmm.lib")// Max time one frame can take (Clamped to this max value)static const DWORD s_dwMaxFrameTime = 1000;// Frame time threshold (in ms) under which QPC result is usedstatic const DWORD s_dwQPCThreshold = 5;//============================================================================PTimer::PTimer() :	m_dwStartTime(0),	m_nIndex(0),	m_bFirstLoop(true){	timeBeginPeriod(1);	QueryPerformanceFrequency(&m_liFreq);	m_liStart.QuadPart = 0;	for(size_t i=0; i<ms_nFramesAverage; ++i)		m_fFrameTimes = 0.0f;}PTimer::~PTimer(){	timeEndPeriod(1);}//============================================================================void PTimer::BeginFrame(){	m_dwStartTime = timeGetTime();	QueryPerformanceCounter(&m_liStart);}void PTimer::EndFrame(){	// Get frame time (via QPC and timeGetTime())	LARGE_INTEGER liFrameTime;	QueryPerformanceCounter(&liFrameTime);	liFrameTime.QuadPart -= m_liStart.QuadPart;	DWORD dwFrameTime = timeGetTime() - m_dwStartTime;	bool bUseTimeGetTime;	float fTime = 0.0f;	// If this was a fast frame, use QPC, and check results with timeGetTime	if(dwFrameTime < s_dwQPCThreshold)	{		fTime = ((float)(liFrameTime.QuadPart*1000) / (float)m_liFreq.QuadPart);		// Validate nonsense answers		if(fTime > (float)s_dwQPCThreshold)			bUseTimeGetTime = true;		else			bUseTimeGetTime = false;	}	else		bUseTimeGetTime = true;	// This was a slow frame, don't care what QPC says, use timeGetTime	if(bUseTimeGetTime)	{		if(dwFrameTime > s_dwMaxFrameTime)			dwFrameTime = s_dwMaxFrameTime;		fTime = (float)dwFrameTime;	}	// Record frame	m_fFrameTimes[m_nIndex++] = fTime;	if(m_nIndex >= ms_nFramesAverage)	{		m_bFirstLoop = false;		m_nIndex = 0;	}	// Calculate total	float fTotal = m_fFrameTimes[0];	for(size_t i=1; i<ms_nFramesAverage; ++i)		fTotal += m_fFrameTimes;	// Average	if(m_bFirstLoop)		m_fFrameTime = fTotal / (float)m_nIndex;	else		m_fFrameTime = fTotal / (float)ms_nFramesAverage;}//============================================================================

void PApp::MainLoop(){	do	{		m_timer.BeginFrame();		Loop(true);		m_timer.EndFrame();	} while(!ShouldExit());}