VC中如何配置OpenGL.doc

VC中如何配置OpenGL李永红摘要： 阐述了Windows中如何设置引用OpenGL进行三维图形绘制，在VC和openGL之间建立桥梁和纽带。关键词：OpenGL，VC程序设计1. 概述OpenGL（全写Open Graphics Library）是个定义了一个跨编程语言、跨平台的编程接口的规格，它用于三维图像。OpenGL是个专业的图形程序接口，是一个功能强大、调用方便的底层图形库。OpenGL能够兼容Windows系统，但不能提供图形用户界面，本文特别介绍了如何在VC中引用OpenGL进行图形绘制。2. 直接将OpenGL绘制的图形输出到系统窗口利用VC的AppWizard建立单文档界面的工程文件，在VC环境中进行编译。2.1 建立适合于OpenGL的运行环境调用VC设置，将OpenGL所在的头文件目录和静态库文件添加到文件目录中，选择连接设置，增加连接库“opengl32.lib glu32.lib glaux.li”，打开stdafx.h文件，在该文件中加入#include#include2.2 在VC生成的视类中添加BOOL SetWindowPixelFormat(HDC hDC)，并给予实现。BOOL CTestOpenGLView:SetWindowPixelFormat(HDC hDC)PIXELFORMATDESCRIPTOR pixelDesc;pixelDesc.nSize=sizeof(PIXELFORMATDESCRIPTOR);pixelDesc.nVersion=1;pixelDesc.dwFlags=PFD_DRAW_TO_WINDOW|PFD_DRAW_TO_BITMAP|PFD_SUPPORT_OPENGL|PFD_SUPPORT_GDI|PFD_STEREO_DONTCARE;pixelDesc.iPixelType=PFD_TYPE_RGBA;pixelDesc.cColorBits=32;pixelDesc.cRedBits=8;pixelDesc.cRedShift=16;pixelDesc.cGreenBits=8;pixelDesc.cGreenShift=8;pixelDesc.cBlueBits=8;pixelDesc.cBlueShift=0;pixelDesc.cAlphaBits=0;pixelDesc.cAlphaShift=0;pixelDesc.cAccumBits=64;pixelDesc.cAccumRedBits=16;pixelDesc.cAccumGreenBits=16;pixelDesc.cAccumBlueBits=16;pixelDesc.cAccumAlphaBits=0;pixelDesc.cDepthBits=32;pixelDesc.cStencilBits=8;pixelDesc.cAuxBuffers=0;pixelDesc.iLayerType=PFD_MAIN_PLANE;pixelDesc.bReserved=0;pixelDesc.dwLayerMask=0;pixelDesc.dwVisibleMask=0;pixelDesc.dwDamageMask=0;m_GLPixelIndex = ChoosePixelFormat(hDC, &pixelDesc);if(m_GLPixelIndex=0)m_GLPixelIndex=1;if(DescribePixelFormat(hDC,m_GLPixelIndex,sizeof(PIXELFORMATDESCRIPTOR),&pixelDesc)=0)return FALSE;if(SetPixelFormat(hDC,m_GLPixelIndex, &pixelDesc)=FALSE)return FALSE;if(CreateViewGLContext( hDC ) = FALSE)return 0;return TRUE;在视类头文件中添加成员变量int m_GLPixelIndex; 2.3 建立函数使得程序的设备描述符CDC与OpenGL发生联系。BOOL CTestOpenGLView:CreateViewGLContext(HDC hDC)m_hGLContext=wglCreateContext(hDC);if(m_hGLContext=NULL)return FALSE;if(wglMakeCurrent(hDC,m_hGLContext)=FALSE)return FALSE;return TRUE;在头文件中添加以下成员变量：HGLRC m_hGLContext; /protect2.4 重载OnCreate函数，在其中加入调用OpenGL的语句int CTestOpenGLView:OnCreate(LPCREATESTRUCT lpCreateStruct)if (CView:OnCreate(lpCreateStruct) = -1)return -1;/ TODO: Add your specialized creation code hereHWND hWnd = GetSafeHwnd();HDC hDC = :GetDC(hWnd);if(SetWindowPixelFormat( hDC ) = FALSE)return 0;return 0;2.5 在OnSize()中增加与OpenGL坐标设置相关的代码。void CTestOpenGLView:OnSize(UINT nType, int cx, int cy)CView:OnSize(nType, cx, cy);/ TODO: Add your message handler code hereGLsizei width, height;GLdouble aspect;width = cx;height = cy;if(cy=0)aspect = (GLdouble)width;elseaspect = (GLdouble)width/(GLdouble)height;glViewport(0, 0, width, height);glMatrixMode(GL_PROJECTION);glLoadIdentity();glMatrixMode(GL_MODELVIEW);glLoadIdentity();2.6 重载OnDestroy( )函数，在其中增加释放资源、恢复系统环境的代码。void CTestOpenGLView:OnDestroy()CView:OnDestroy();/ TODO: Add your message handler code hereif(wglGetCurrentContext()!=NULL)/make the rendering context not currentwglMakeCurrent(NULL,NULL);if(m_hGLContext!=NULL)wglDeleteContext(m_hGLContext);m_hGLContext=NULL;2.7 在onDraw（）中加入OpenGL的三维图形绘制代码，可以直接将openGL的绘制结果输出到VC的视框中。void CTestOpenGLView:OnDraw(CDC* /*pDC*/)CTestOpenGLDoc* pDoc = GetDocument();ASSERT_VALID(pDoc);if (!pDoc)return;/ TODO: add draw code for native data hereglLoadIdentity();glClear(GL_COLOR_BUFFER_BIT);glBegin(GL_QUADS); glColor4f(1.0f, 0.0f, 0.0f, 1.0f); glVertex3f(-0.5f, -0.5f, 1.0f); glColor4f(0.0f,1.0f,0.0f,1.0f); glVertex3f( 0.0f, -0.5f, 1.0f); glColor4f(0.0f,0.0f,1.0f,1.0f); glVertex3f( -0.5f, 0.5f, -1.0f); glColor4f(0.0f,1.0f,1.0f,1.0f); glVertex3f(0.5f, 0.5f, 0.0f);glEnd();glFlush();2.8 软件最终运行效果3. 将OpenGL绘制的图形输出为位图在某些窗体中，可以利用位图作为中间介质，将OpenGL三维图形的绘制结果输出到位图，利用位图进行图像的显示。3.1 位图类的设计利用位图作为桥梁，必须先设计位图类，该类具有创建位图、存储位图、显示位图、调入位图等操作成员，位图类的设计较多，此处不再阐述。3.2 利用VC中的Appwizard设计一个基于对话框的类，在其中加入静态框，然后加入基于CWnd的类，在类中，加入成员变量：CreateOpenGL( )、SetLogicalPalette( )、 DestroyOpenGL( )等，其中，最重要的是CreateOpenGL( )，具体实现代码为：int CGraphDraw:CreateOpenGL()CDC *dc;HDC hDC;m_DIB.Create(m_cx,m_cy,24);dc=m_DIB.GetDC( );hDC=dc-GetSafeHdc();CBitmap *pBitmap=dc-GetCurrentBitmap();BITMAP bmInfo;pBitmap-GetObject(sizeof(BITMAP),&bmInfo);PIXELFORMATDESCRIPTOR pfd = sizeof(PIXELFORMATDESCRIPTOR), 1, PFD_DRAW_TO_BITMAP | PFD_SUPPORT_OPENGL | PFD_SUPPORT_GDI, PFD_TYPE_RGBA, 16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 32, 0, 0, PFD_MAIN_PLANE, 0, 0, 0, 0 ; int pixelformat;pixelformat = :ChoosePixelFormat(hDC, &pfd);SetPixelFormat(hDC, pixelformat, &pfd);if(pfd.dwFlags & PFD_NEED_PALETTE)SetLogicalPalette(); m_hRC = wglCreateContext( hDC ); wglMakeCurrent( hDC, m_hRC ); glClearDepth(1.0); glDepthFunc(GL_LEQUAL); glPointSize(1.0); glLineWidth(1.0); glCullFace(GL_BACK); ReleaseDC(dc);return 0; 在上述代码中，最重要的代码是上述中的黑体部分，获得的设备描述符来自位图。3.3 程序中调用CRect r;CDC *pDC = m_Graph.GetDC();m_Graph.GetClientRect(&r);m_Graph.m_cx = r.Width();m_Graph.m_cy = r.Height();m_Graph.CreateOpenGL();glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );glMatrixMode( GL_PROJECTION );glLoadIdentity();glOrtho(-1.0,1.0,-1.0,1.0,-1.0,1.0);glColor3f(0.75f,0.75f,0.0f);glBegin(GL_LINES); glVertex3f(-1.0f,-0.3f,0.0f); glVertex3f(1.0f,-0.3f,0.0f);glEnd();glBegin(GL_LINES); glVertex3f(0.0f,-0.3f,0.0f); glVertex3f(0.0f,0.5f,0.0f);glEnd();glBegin(GL_LINES); glVertex3f(0.0f,0.5f,0.0f); glVertex3f(-0.02f,0.45f,0.0f);