這邊先引用別人寫的比較好的文章，以便快速的瞭解關於framebuffer的一些函式。

《-------------------------------------------------------------------一下內容為引用-----------------------------------------------------------------------》

《------------------------------------------------------------------------以上內容為引用-----------------------------------------------------------------------》

看完上面的內容，你應該對FrameBuffer有一個比較完整的瞭解，其實我要做的是整理framebuffer程式為介面，以便被使用。

CFramebuffer.h

#pragma once

#include <gl/glew.h>
#include <glut.h>
#include <cv.h>
#include <highgui.h>

class CFrameBuffer
{
public:
	CFrameBuffer();
public:
	~CFrameBuffer();
private:
	unsigned int m_FboID;
	unsigned int m_RboID;
	unsigned int m_tex;
	bool     m_bIsBegined;
	int      m_curbuff;

public:
	int     m_width;
	int		m_height;

public:
	void init(int width, int height);
	bool begin();
	bool end();
	void saveFrameBuff(const char* fileName);

	unsigned int getTex(){return m_tex;}
};

CFramebuffer.cpp

#include "stdafx.h"

#include <iostream>
#include "CFrameBuffer.h"
CFrameBuffer::CFrameBuffer()
{
	m_FboID = 0;
	m_RboID = 0;
	m_tex   = 0;
	m_bIsBegined = false;
	m_width = 0;
	m_height = 0;
	m_curbuff = 0;
}

CFrameBuffer::~CFrameBuffer()
{
	if(m_bIsBegined)
	{
		end();
		m_bIsBegined = false;
	}
	glDeleteTextures(1,&m_tex);
	glDeleteRenderbuffersEXT(1,&m_RboID);
	glDeleteFramebuffersEXT(1,&m_FboID);
}

void CFrameBuffer::init(int width, int height)
{
	glewInit();
	m_width = width;
	m_height = height;

	glEnable(GL_TEXTURE_2D);
	glGenTextures(1,&m_tex);
	glBindTexture(GL_TEXTURE_2D,m_tex);

	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_CLAMP);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_CLAMP);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
	glTexImage2D(GL_TEXTURE_2D,0,GL_RGBA,m_width,m_height,0,GL_BGR,GL_UNSIGNED_BYTE,NULL);
	glBindTexture(GL_TEXTURE_2D,0);
	glDisable(GL_TEXTURE_2D);

	glEnable(GL_RENDERBUFFER_EXT);
	glGenRenderbuffersEXT(1,&m_RboID);
	glBindRenderbufferEXT(GL_RENDERBUFFER_EXT,m_RboID);
	glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT,GL_DEPTH_COMPONENT,m_width,m_height);
	glBindRenderbufferEXT(GL_RENDERBUFFER_EXT,0);
	glDisable(GL_RENDERBUFFER_EXT);

	glEnable(GL_FRAMEBUFFER_EXT);
	glGenFramebuffersEXT(1,&m_FboID);
	glBindFramebufferEXT(GL_FRAMEBUFFER_EXT,m_FboID);
	glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT,GL_COLOR_ATTACHMENT0_EXT,GL_TEXTURE_2D,m_tex,0);
	glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,GL_DEPTH_ATTACHMENT_EXT,GL_RENDERBUFFER_EXT,m_RboID);
	

	GLenum status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);

	if(status != GL_FRAMEBUFFER_COMPLETE_EXT)
	{
		switch(status)
		{
		case GL_FRAMEBUFFER_COMPLETE_EXT:
			std::cout << "Framebuffer complete." << std::endl;
			break;

		case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT_EXT:
			std::cout << "[ERROR] Framebuffer incomplete: Attachment is NOT complete." << std::endl;
			break;

		case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT_EXT:
			std::cout << "[ERROR] Framebuffer incomplete: No image is attached to FBO." << std::endl;
			break;

		case GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS_EXT:
			std::cout << "[ERROR] Framebuffer incomplete: Attached images have different dimensions." << std::endl;
			break;

		case GL_FRAMEBUFFER_INCOMPLETE_FORMATS_EXT:
			std::cout << "[ERROR] Framebuffer incomplete: Color attached images have different internal formats." << std::endl;
			break;

		case GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER_EXT:
			std::cout << "[ERROR] Framebuffer incomplete: Draw buffer." << std::endl;
			break;

		case GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER_EXT:
			std::cout << "[ERROR] Framebuffer incomplete: Read buffer." << std::endl;
			break;

		case GL_FRAMEBUFFER_UNSUPPORTED_EXT:
			std::cout << "[ERROR] Unsupported by FBO implementation." << std::endl;
			break;

		default:
			std::cout << "[ERROR] Unknow error." << std::endl;
			break;
		}
	}
	glBindFramebufferEXT(GL_FRAMEBUFFER_EXT,0);
	glDisable(GL_FRAMEBUFFER_EXT);
	
	m_curbuff = 0;
}

bool CFrameBuffer::begin()
{
	if(m_bIsBegined)
	{
		return false;
	}
	else
	{
		//glPushAttrib(GL_ALL_ATTRIB_BITS);
		//glGetIntegerv(GL_FRAMEBUFFER_BINDING_EXT,&m_curbuff);
		//glBindFramebufferEXT(GL_FRAMEBUFFER_EXT,m_FboID);

		glGetIntegerv(GL_FRAMEBUFFER_BINDING_EXT,&m_curbuff);
		glPushAttrib(GL_VIEWPORT_BIT);
		glMatrixMode(GL_PROJECTION);
		glPushMatrix();
		glMatrixMode(GL_MODELVIEW);
		glPushMatrix();

		glBindFramebufferEXT(GL_FRAMEBUFFER_EXT,m_FboID);
		//cout<<"begin after : GL_FRAMEBUFFER_BINDING_EXT = "<<FboId<<endl;
		glViewport(0,0,m_width,m_height);
		glMatrixMode(GL_PROJECTION);
		glLoadIdentity();
		glOrtho(0,m_width,0,m_height,-1000,1000);
		glMatrixMode(GL_MODELVIEW);
		glLoadIdentity();

		m_bIsBegined = true;
		return true;
	}
}

bool CFrameBuffer::end()
{
	if(m_bIsBegined)
	{
		//glPopAttrib();
		//glBindFramebufferEXT(GL_FRAMEBUFFER_EXT,m_curbuff);
		glMatrixMode(GL_MODELVIEW);
		glPopMatrix();
		glMatrixMode(GL_PROJECTION);
		glPopMatrix();
		glPopAttrib();

		glBindFramebufferEXT(GL_FRAMEBUFFER_EXT,m_curbuff);
		m_bIsBegined = false;
		return true;
	}
	else
	{
		return false;
	}
}

void CFrameBuffer::saveFrameBuff(const char* fileName)
{
	IplImage* pImage = cvCreateImage(cvSize(m_width,m_height),8,3);
	glEnable(GL_TEXTURE_2D);
	glBindTexture(GL_TEXTURE_2D,m_tex);
	glGetTexImage(GL_TEXTURE_2D,0,GL_BGR,GL_UNSIGNED_BYTE,pImage->imageData);
	glDisable(GL_TEXTURE_2D);

	cvFlip(pImage,NULL,0);
	cvSaveImage(fileName,pImage);
	cvReleaseImage(&pImage);
}

上面已經很詳細寫出的framebuffer的內容，你只要在draw函式之前呼叫begin()和draw函式之後用end()就可以完成將紋理繪製到framebuffer中了，這裡還使用一個函式來儲存framebuffer的紋理到圖片，接觸到OpenCV的一些函式。