Elysian Shadows

Code: Select all

#ifndef _PERFTIMER_H
#define _PERFTIMER_H

#include <windows.h>
#include <string>
#include <mmsystem.h> 
#include <ctime>
using namespace std;

#define STRING_SIZE    255

class PerfTimer
{
protected:
	double m_TimeScale;
	double m_Time;
	double m_DeltaTime;

	unsigned int m_FrameCount;
	double m_ElapsedTime ;
	TCHAR *m_Buffer; 
	wstring m_Output;

public:
	PerfTimer();
        ~PerfTimer();
	double GetTime();
	void SetTime();
	double DeltaTime(PerfTimer & P1);
	void OutputFrameRate(HWND & windowHandle);
};

Code: Select all

#include "PerfTimer.h"

PerfTimer::PerfTimer()
{
	__int64 countsPerSecond = 0;
	if(QueryPerformanceFrequency((LARGE_INTEGER*)&countsPerSecond) != 0)
	{
		m_TimeScale = 1.0 / (double)countsPerSecond;
	}
	else
	{
		m_TimeScale = 0.0;
		m_Time = 0.0;	// set to zero if no performance timer available
	}
	m_FrameCount = 0;
	m_ElapsedTime = 0.0;
        m_Buffer = new TCHAR[STRING_SIZE];
}

PerfTimer::~PerfTimer() {
       delete[] m_Buffer;
}

double PerfTimer::GetTime()
{
	return m_Time;
}

void PerfTimer::SetTime()
{
	__int64 currentTime = 0;
	QueryPerformanceCounter((LARGE_INTEGER*)&currentTime);
	m_Time = currentTime * m_TimeScale;
}

double PerfTimer::DeltaTime(PerfTimer & P1)
{
	m_DeltaTime = GetTime() - P1.GetTime();
	return m_DeltaTime;
}

void PerfTimer::OutputFrameRate(HWND & windowHandle)
{
	// increment the frame count
	m_FrameCount++;

	// calculate how much time has passed since the last frame
	m_ElapsedTime += m_DeltaTime;
	// if 1 second has passed
	if( m_ElapsedTime >= 1.0 )
	{
		// calculate frames per second.
		// FPS = frameCnt / timeElapsed however only computed when elapsedTime = 1.0 
		// Therefore FPS = frameCnt / 1.0 = frameCnt.

		m_Output = L"Frames Per Second = ";
		_itow_s(m_FrameCount,m_Buffer,20,10);
		m_Output += m_Buffer;

		// set the window caption 
		SetWindowText(windowHandle, m_Output.c_str());

		// Reset
		m_FrameCount = 0;
		m_ElapsedTime = 0.0f;
	}
}

Code: Select all

        ...

	PerfTimer P1;
	PerfTimer P2;
	P1.SetTime();
	double sleepElapsedTime = 0.0;

	// Game loop!
	while (1)
	{
		
		P2.SetTime();	// Get current time
		sleepElapsedTime += P2.DeltaTime ( P1 );     // Get Delta time
		P2.OutputFrameRate( hwnd );		          // Output FPS to caption (Pass the window handle)		
			
		SwapBuffers(hDC);

		while (PeekMessage (&msg, NULL, 0, 0, PM_NOREMOVE))		
		{
			if (!GetMessage (&msg, NULL, 0, 0))			
			{
				PostQuitMessage(0);
				break;
			}

			TranslateMessage (&msg);
			DispatchMessage (&msg);
		}

		P1 = P2;		
	}