在本机窗口opengl c ++中获得准确帧率（每秒帧数）的好方法是什么？
答案 0 :(得分：6)
这是我过去在ATL项目中使用的计时器类。暂时没有完成C ++或opengl，但也许这会给你一些想法：
// Put this in your class somewhere
CTimer m_timer;
// Initialize the timer using
m_timer.Init();
// Call this everytime you call draw your scene
m_timer.Update();
// Call this to get the frames/sec
m_timer.GetFPS();
// Timer.h: Timer class used for determining elapsed time and
// frames per second.
//
//////////////////////////////////////////////////////////////////////
#ifndef _E_TIMER_H
#define _E_TIMER_H
#pragma once
//////////////////////////////////////////////////////////////////////
// INCLUDES
//////////////////////////////////////////////////////////////////////
#include <windows.h>
#include <stdio.h>
#include <math.h>
//////////////////////////////////////////////////////////////////////
// CLASSES
//////////////////////////////////////////////////////////////////////
class CTimer
{
private:
//performance timer variables
__int64 m_i64PerformanceTimerStart;
__int64 m_i64PerformanceTimerElapsed;
//multimedia timer variables
unsigned long m_ulMMTimerElapsed;
unsigned long m_ulMMTimerStart;
//general timer variables
__int64 m_i64Frequency;
float m_fResolution;
bool m_bPerformanceTimer;
//FPS variables
float m_fTime1;
float m_fTime2;
float m_fDiffTime;
float m_fFPS;
int m_iFramesElapsed;
public:
//----------------------------------------------------------
// Name: CTimer::CTimer
// Desc: Default constructor
// Args: None
// Rets: None
//----------------------------------------------------------
CTimer( void )
: m_fFPS(0.0f), m_fTime1(0.0f), m_fTime2(0.0f), m_fDiffTime(0.0f), m_iFramesElapsed(0)
{ }
//----------------------------------------------------------
// Name: CTimer::CTimer
// Desc: Default destructor
// Args: None
// Rets: None
//----------------------------------------------------------
virtual ~CTimer( void )
{ }
//----------------------------------------------------------
// Name: CTimer::Init - public
// Desc: Initiate the timer for the program
// Args: None
// Rets: bool: -true: using performance timer
// -false: using multimedia timer
//----------------------------------------------------------
bool Init( void )
{
//check to see if we are going to be using the performance counter
if( QueryPerformanceFrequency( ( LARGE_INTEGER* )&m_i64Frequency ) )
{
//we are able to use the performance timer
m_bPerformanceTimer= true;
//get the current time and store it in m_i64PerformanceTimerStart
QueryPerformanceCounter( ( LARGE_INTEGER* )&m_i64PerformanceTimerStart );
//calculate the timer resolution
m_fResolution= ( float )( ( ( double )1.0f )/( ( double )m_i64Frequency ) );
//initialize the elapsed time variable
m_i64PerformanceTimerElapsed= m_i64PerformanceTimerStart;
}
//we cannot use the performence counter, so we'll use the multimedia counter
else
{
//we're using the multimedia counter
m_bPerformanceTimer= false;
m_ulMMTimerStart = timeGetTime( ); //record the time the program started
m_ulMMTimerElapsed = m_ulMMTimerStart; //initialize the elapsed time variable
m_fResolution = 1.0f/1000.0f;
m_i64Frequency = 1000;
}
return m_bPerformanceTimer;
}
//----------------------------------------------------------
// Name: CTimer::Update - public
// Desc: Update the timer (perform FPS counter calculations)
// Args: None
// Rets: None
//----------------------------------------------------------
void Update( void )
{
//increase the number of frames that have passed
m_iFramesElapsed++;
if ( m_iFramesElapsed % 5 == 1 )
m_fTime1 = GetTime( )/1000;
else if ( m_iFramesElapsed % 5 == 0 )
{
m_fTime1 = m_fTime2;
m_fTime2 = GetTime( )/1000;
m_fDiffTime= ( float )fabs( m_fTime2-m_fTime1 );
}
m_fFPS= 5/( m_fDiffTime );
/*m_fTime2 = GetTime( )/1000;
m_fDiffTime= ( float )fabs( m_fTime2-m_fTime1 );
if (m_fDiffTime > 1.0f)
{
m_fTime1 = m_fTime2;
m_fFPS= m_iFramesElapsed / ( m_fDiffTime );
m_iFramesElapsed = 0;
}
*/
}
//----------------------------------------------------------
// Name: CTimer::GetTime - public
// Desc: Get the current time since the program started
// Args: None
// Rets: float: The time elapsed since the program started.
//----------------------------------------------------------
float GetTime( void )
{
__int64 i64Time;
//check to see if we are using the performance counter
if( m_bPerformanceTimer )
{
//get the current performance time
QueryPerformanceCounter( ( LARGE_INTEGER* )&i64Time );
//return the time since the program started
return ( ( float )( i64Time - m_i64PerformanceTimerStart )*m_fResolution )*1000.0f;
}
//we are using the multimedia counter
else
{
//return the time since the program started
return ( ( float )( timeGetTime( ) - m_ulMMTimerStart )*m_fResolution )*1000.0f;
}
}
//----------------------------------------------------------
// Name: CTimer::GetElapsedSeconds - public
// Desc: Get the elapsed seconds since the last frame was drawn.
// Args: elapsedFrames:
// Rets: float: The time elapsed since the program started.
//----------------------------------------------------------
float GetElapsedSeconds(unsigned long elapsedFrames = 1)
{ return m_fDiffTime; }
//----------------------------------------------------------
// Name: CTimer::GetFPS - public
// Desc: Get the current number of frames per second
// Args: None
// Rets: float: the number of frames per second
//----------------------------------------------------------
inline float GetFPS( void )
{ return m_fFPS; }
};
#endif // _E_TIMER_H
答案 1 :(得分：0)
在c ++中，我最喜欢的计时器与史蒂夫建议的相同。
在你的opengl应用程序中可能还存在禁用vsync的问题，对我来说，默认情况下它始终处于启用状态，你必须加载一些函数来禁用它。
可能更多与平台无关的解决方案，
使用time.h
我记不起函数:(但它会返回你的应用程序在几秒钟内运行的时间，在这种情况下，只计算在几秒钟之间传递的帧数，这就是你的fps（假设函数GetTime（））
// in your loop:
//////////
static int lastTime = GetTime();
static int framesDone = 0;
int currentTime = GetTime();
if(currentTime > lastTime)
{
int fps = framesDone;
framesDone = 0;
lastTime = currentTime;
}
framesDone++;
/////////
但是，对于Windows来说，第一个答案是最好的。
如果您需要帮助来禁用vsync，请告诉我们。