【转】MFC中建立OpenGL窗口
【转】http://hi.baidu.com/lmhopen/blog/item/0282dccbdbbbf21bbf09e62f.html
三种建立OpenGL窗口的方法,
一种是win32 sdk加OpenGL函数,这种方法写起来极其麻烦,很是繁琐,
第二种把建立OpenGL环境所用到的OpenGL函数写成一个小类,然后用win32 sdk加OpenGL类的方式建立OpenGL窗口,这种方法比前一个方法简洁清晰了点,不过还是感觉繁琐.
第三种方法用MFC编程建立OpenGL窗口,这种方法我最推崇.因为首先用MFC建立windows窗口方便简洁.其次可以考虑把要用到的OpenGL函数编成一个类,这样用起OpenGL来更是简洁方便了.
我现在手头有这三种代码,但我以后主要用MFC来写OpenGL程序,下边把如何用MFC建立一个最基本的OpenGL窗口贴出来.
首先是头文件:
// smotri.h
// smotri - Simple MFC, C++, OpenGL Tutorial Program
// by: Joel Parris
// date: 10/9/2000
#include <afxwin.h> // MFC Windows include file
#include <GL/gl.h> // OpenGL include file
#include <GL/glu.h> // OpenGL Utilities include file
#include <math.h>
class CSmotri: public CWinApp
{
public:
virtual BOOL InitInstance();
};
class COpenGLWindow: public CFrameWnd
{
public:
COpenGLWindow(); // COpenGLWindow Class Constructor
~COpenGLWindow(); // COpenGLWindow Class Constructor
HDC m_hgldc; // GDI Device Context
HGLRC m_hglRC; // Rendering Context
BOOL SetPixelformat(HDC hdc);
void GetGLInfo();
int DrawGLScene(void);
int InitGL(void);
void ReSizeGLScene(int width, int height);
//virtual BOOL PreCreateWindow( CREATESTRUCT& cs );
protected:
afx_msg void OnPaint();
afx_msg int OnCreate(LPCREATESTRUCT lpCreateStruct);
afx_msg void OnSize(UINT nType, int cx, int cy );
afx_msg BOOL OnEraseBkgnd( CDC* pDC );
afx_msg void OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags);
DECLARE_MESSAGE_MAP()
};
然后是CPP文件:
// smotri - Simple MFC, C++, OpenGL Tutorial Program
// by: Joel Parris
// date: 1/21/2001
#include "smotri.h"
//#include "timer.h"
CSmotri Smotri; // Instantiate the Smotri application
////////////////////////////////////////////////////////////////////
// CMyApp Member Function
BOOL CSmotri::InitInstance() // Initialize Smotri
{
m_pMainWnd = new COpenGLWindow;
// m_nCmdShow = SW_SHOWMAXIMIZED; // Comment to UnMaximize the Window
m_pMainWnd -> ShowWindow(m_nCmdShow);
m_pMainWnd -> UpdateWindow();
return true;
}
////////////////////////////////////////////////////////////////////
// COpenGLWindow message map and Member functions
BEGIN_MESSAGE_MAP(COpenGLWindow, CFrameWnd)
ON_WM_PAINT()
ON_WM_CREATE()
ON_WM_SIZE()
ON_WM_ERASEBKGND()
ON_WM_KEYDOWN()
END_MESSAGE_MAP()
COpenGLWindow::COpenGLWindow()
{
Create( NULL, _T("Smotri - a Simple MFC OpenGL Application"),
WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN | WS_CLIPSIBLINGS | CS_OWNDC);
//ModifyStyle(WS_CAPTION, 0, SWP_FRAMECHANGED);
}
COpenGLWindow::~COpenGLWindow()
{
wglMakeCurrent(NULL,NULL);
wglDeleteContext(m_hglRC);
}
/*BOOL COpenGLWindow::PreCreateWindow( CREATESTRUCT& cs )
{
if(!CFrameWnd::PreCreateWindow(cs))
return FALSE;
// Set the initial size of the window
cs.cx = 550;
cs.cy = 400;
return TRUE;
}*/
BOOL COpenGLWindow::OnEraseBkgnd( CDC* pDC )
{
/* This overrides the MFC Message Loop's OnEraseBkgnd(), which
keeps the OpenGL window from flashing. I shouldn't tell you
this but contrary to popular opinion it doesn't matter what this
override returns TRUE or FALSE. If you don't believe me, try it
for yourself.
*/
return TRUE;
}
void COpenGLWindow::OnSize(UINT nType, int cx, int cy )
{
ReSizeGLScene( cx, cy );
}
void COpenGLWindow::OnPaint()
{
CPaintDC dc(this); // Needed
//QueryPerformanceFrequency(&timerFrequency); // Initialize timer
//QueryPerformanceCounter(&startCount); // Start timer
// process block
int imax = 100;
for (int i = 1; i <= imax; i++) // Draw the scene 100 times
{
DrawGLScene(); // Render the OpenGL scene
}
// end, process block
//QueryPerformanceCounter(&endCount); // Stop timer
//double time = interval_time( startCount, endCount );
//output_time( time );
SwapBuffers(m_hgldc);
}
BOOL COpenGLWindow::SetPixelformat(HDC hdc)
{
PIXELFORMATDESCRIPTOR *ppfd;
int pixelformat;
PIXELFORMATDESCRIPTOR pfd = {
sizeof(PIXELFORMATDESCRIPTOR), // size of this pfd
1, // version number
PFD_DRAW_TO_WINDOW | // support window
PFD_SUPPORT_OPENGL | // support OpenGL
PFD_GENERIC_FORMAT |
PFD_DOUBLEBUFFER, // double buffered
PFD_TYPE_RGBA, // RGBA type
32, // 32-bit color depth
0, 0, 0, 0, 0, 0, // color bits ignored
8, // no alpha buffer
0, // shift bit ignored
8, // no accumulation buffer
0, 0, 0, 0, // accum bits ignored
64, // 64-bit z-buffer
8, // stencil buffer
8, // auxiliary buffer
PFD_MAIN_PLANE, // main layer
0, // reserved
0, 0, 0 // layer masks ignored
};
ppfd = &pfd;
if ( (pixelformat = ChoosePixelFormat(hdc, ppfd)) == 0 )
{
::MessageBox(NULL, "ChoosePixelFormat failed", "Error", MB_OK);
return FALSE;
}
if (SetPixelFormat(hdc, pixelformat, ppfd) == FALSE)
{
::MessageBox(NULL, "SetPixelFormat failed", "Error", MB_OK);
return FALSE;
}
return TRUE;
}
int COpenGLWindow::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
m_hgldc = ::GetDC(m_hWnd); // Get a device context for OpenGL
if(!SetPixelformat(m_hgldc)) // set pixel format
{
::MessageBox(::GetFocus(),"SetPixelformat Failed!","Error",MB_OK);
return -1;
}
m_hglRC = wglCreateContext(m_hgldc); // Create an OpenGL rendering context
int i= wglMakeCurrent(m_hgldc,m_hglRC); // Make rendering context current
GetGLInfo(); // Get OpenGL information
InitGL(); // Initialize OpenGL
return 0;
}
void COpenGLWindow::GetGLInfo() // Get OpenGL Information
{
CString oglinfo;
oglinfo = "OpenGL Information\n\nWho: ";
oglinfo += ::glGetString( GL_VENDOR );
oglinfo += "\nWhich: ";
oglinfo += ::glGetString( GL_RENDERER );
oglinfo += "\nVersion: ";
oglinfo += ::glGetString( GL_VERSION );
oglinfo += "\nExtensions: ";
oglinfo += ::glGetString( GL_EXTENSIONS );
AfxMessageBox(oglinfo,MB_ICONINFORMATION); // Display OpenGL Information
}
void COpenGLWindow::ReSizeGLScene( int width, int height) // Resize And Initialize The GL Window
{
// from NeHe's Tutorial 3
if (height==0) // Prevent A Divide By Zero By
{
height=1; // Making Height Equal One
}
glViewport(0,0,width,height); // Reset The Current Viewport
glMatrixMode(GL_PROJECTION); // Select The Projection Matrix
glLoadIdentity(); // Reset The Projection Matrix
// Calculate The Aspect Ratio Of The Window
gluPerspective(45.0,(float)width/(float)height,0.1,100.0);
glMatrixMode(GL_MODELVIEW); // Select The Modelview Matrix
glLoadIdentity(); // Reset The Modelview Matrix
}
int COpenGLWindow::InitGL(void) // Intitialize OpenGl // All Setup For OpenGL Goes Here
{
// from NeHe's Tutorial 3
glShadeModel(GL_SMOOTH); // Enable Smooth Shading
glClearColor(0.0, 0.0, 0.0, 0.5); // Black Background
glClearDepth(1.0); // Depth Buffer Setup
glEnable(GL_DEPTH_TEST); // Enables Depth Testing
glDepthFunc(GL_LEQUAL); // The Type Of Depth Testing To Do
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); // Really Nice Perspective Calculations
return TRUE; // Initialization Went OK
}
int COpenGLWindow::DrawGLScene(void) // Here's Where We Do All The Drawing
{
// from NeHe's Tutorial 3
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear Screen And Depth Buffer
glLoadIdentity(); // Reset The Current Modelview Matrix
glTranslated(-1.5,0.0,-6.0); // Move Left 1.5 Units And Into The Screen 6.0
glBegin(GL_TRIANGLES); // Drawing Using Triangles
glColor3d(1.0,0.0,0.0); // Set The Color To Red
glVertex3d( 0.0, 1.0, 0.0); // Top
glColor3d(0.0,1.0,0.0); // Set The Color To Green
glVertex3d(-1.0,-1.0, 0.0); // Bottom Left
glColor3d(0.0,0.0,1.0); // Set The Color To Blue
glVertex3d( 1.0,-1.0, 0.0); // Bottom Right
glEnd(); // Finished Drawing The Triangle
glTranslated(3.0,0.0,0.0); // Move Right 3 Units
glColor3d(0.5,0.5,1.0); // Set The Color To Blue One Time Only
glBegin(GL_QUADS); // Draw A Quad
glVertex3d(-1.0, 1.0, 0.0); // Top Left
glVertex3d( 1.0, 1.0, 0.0); // Top Right
glVertex3d( 1.0,-1.0, 0.0); // Bottom Right
glVertex3d(-1.0,-1.0, 0.0); // Bottom Left
glEnd(); // Done Drawing The Quad
// Keep Going
return TRUE;
}
void COpenGLWindow::OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags)
{
switch (nChar)
{
case VK_ESCAPE:
exit(0);
break;
default:
break;
}
}
由于这是MFC程序,所以要在工程设置里选择使用MFC动态或静态连接,在工程设置的LINK选项卡里加上opengl32.lib glu32.lib
（项目->属性->链接器->输入->附加依赖项 中导入相关的lib）
基本步骤就是:
1创建一个windows窗口.
2在OnCreate函数中创建和设置OpenGL环境.
3在OnSize函数中设置OpenGL窗口跟着windows窗口自动调整大小
4在OnPaint函数中使用OpenGL的作图命令,用swappbuffers把图形显示出来
5设置空的onerasebkgnd函数返回TRUE,目的是防止窗口闪烁.
6在窗口类的析构函数中释放环境描述表DC和着色描述表RC,删除RC
基本上用其它方法编OpenGL程序也得是这样的步骤,
