[转载]MFC中OpenGL旋转的问题

原文地址：MFC中OpenGL旋转的问题作者：zero916619

要求用户不干涉的情况下让物体自由旋转，这如果用win32的sdk直接来实现的话，就像Nehe的教程上那样是比较容易做的，可以在空闲事件的情况下调用绘图部分代码；

    if (PeekMessage(&msg,NULL,0,0,PM_REMOVE))    // Is There A Message Waiting?
         {
        
                 TranslateMessage(&msg);                // Translate The Message
                 DispatchMessage(&msg);                // Dispatch The Message
         }
        else                                        // If There Are No Messages
         {
             DrawGLScene()；
         }

但MFC中我不了解到底该怎么弄才好，起先也是想放到空闲事件处理程序中去调用绘图代码，就写了如下代码：

BOOL COpenGLDemoApp::OnIdle(LONG lCount)
{
    // TODO: Add your specialized code here and/or call the base class
     CFrameWnd*    pw=(CFrameWnd*)AfxGetMainWnd();  
     ((COpenGLDemoView*)pw->GetActiveView())->DrawGLScene();
    return CWinApp::OnIdle(lCount);
}

可发现效果不对劲，必须要用户的鼠标在上面滑动才会旋转，和要求完全不符合呀。于是我就换了个想法，试着用了一个定时器，让它定时刷新重绘，从而产生出旋转的效果，代码如下:

int COpenGLDemoView::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
    if (CView::OnCreate(lpCreateStruct) == -1)
        return -1;
    
    // TODO: Add your specialized creation code here
     HWND hWnd = this->GetSafeHwnd();    
     HDC hDC = ::GetDC(hWnd);

    if(this->SetWindowPixelFormat(hDC)==FALSE)
     {//设置像素格式
        return 0;
     }
    if(this->CreateViewGLContext(hDC)==FALSE)
     {//创建RC并选为所用
        return 0;
     }
    if(!this->InitGL())
     {//初始化openGL
        return 0;
     }
    this->SetTimer(1,10,NULL);
    return 0;
}
void COpenGLDemoView::OnPaint()
{
     CPaintDC dc(this); // device context for painting
    this->DrawGLScene();
}
void COpenGLDemoView::OnTimer(UINT nIDEvent)
{
    // TODO: Add your message handler code here and/or call default
    //控制旋转角度
     rTri+=1.2f;
    if(rTri>=360.0f)
     {
         rTri-=360.0f;
     }
     rQuads-=1.15f;
    if(rQuads<=-360.0f)
     {
         rQuads+=360.0f;
     }

     InvalidateRect(NULL,FALSE);//角度更新了，通知其重绘
     CView::OnTimer(nIDEvent);
}
int COpenGLDemoView::DrawGLScene()                                   
{// Here's Where We Do All The Drawing
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);    // Clear Screen And Depth Buffer
     glShadeModel(GL_SMOOTH);
     glLoadIdentity();                                    // Reset The Current Modelview Matrix
     glTranslatef(-1.5f,0.0f,-6.0f);//物体左移1.5,向内移6,相当于移动镜头一样，让物体进入镜头中
     glRotatef(rTri,0.0f,1.0f,0.0f);
     glBegin(GL_TRIANGLES);                            // 绘制三角形
         glColor3f(1.0f,0.0f,0.0f);
         glVertex3f( 0.0f, 1.0f, 0.0f);                    // 上顶点
         glColor3f(0.0f,1.0f,0.0f);
         glVertex3f(-1.0f,-1.0f, 0.0f);                    // 左下
         glColor3f(0.0f,0.0f,1.0f);
         glVertex3f( 1.0f,-1.0f, 0.0f);                    // 右下
     glEnd();                                // 三角形绘制结束
     glShadeModel(GL_FLAT);
     glLoadIdentity();
     glTranslatef(1.5f,0.0f,-6.0f);
     glRotatef(rQuads,1.0f,0.0f,0.0f);
     glBegin(GL_QUADS);                            //   绘制正方形
         glColor3f(1.0f,0.0f,0.0f);
         glVertex3f(-1.0f, 1.0f, 0.0f);                    // 左上
         glColor3f(1.0,1.0f,1.0f);
         glVertex3f(-1.0f,-1.0f, 0.0f);                    // 右下

         glColor3f(0.0f,0.0f,1.0f);
         glVertex3f( 1.0f,-1.0f, 0.0f);                    // 左下
         glColor3f(0.0f,1.0f,0.0f);
         glVertex3f( 1.0f, 1.0f, 0.0f);                    // 右上
     glEnd();                                // 正方形绘制结束
     glFlush();
     rTri+=1.2f;
    if(rTri>=360.0f)
     {
         rTri-=360.0f;
     }
     rQuads-=1.15f;
    if(rQuads<=-360.0f)
     {
         rQuads+=360.0f;
     }
     HWND hWnd = this->GetSafeHwnd();    
     HDC hDC = ::GetDC(hWnd);
     SwapBuffers(hDC);
    return TRUE;                                        // Everything Went OK
}