Hi folks! I'm a total newbie in the field of OpenGL and MFC programming. I managed to run an OpenGL child window within a dialog window, added some controls to it and made some objects rotate by mouse. Now I have two problems: 1 - Where can I place OpenGL commands to set up the OpenGL scene and the camera? I tried to put them everywhere but nothing ever happened. 2 - Where can I create display lists? It's like with problem number one, I put them everywhere and nothing happened. I adapted my code from the tutorial "How to Create a CHILD OpenGL Window in a Dialog" by Marc Guy on www.codeguru.com I hope these questions are not too stupid and maybe someone can answer them. Thank you in advance, Elsenhans

No, I don't use the Document/View architecture. I figured out that I've got a problem with the device and render contexts (OpenGL in dialog window). In my OnPaint() function the contexts are set like this:

void COpenGL::OnPaint()
{
CPaintDC dc(this);
HDC hdc = ::GetDC(m_hWnd);
HGLRC hglrc;
hglrc = wglCreateContext(hdc);
wglMakeCurrent(hdc, hglrc);

//OpenGL commands here
SwapBuffers(hdc);

wglMakeCurrent(NULL, NULL) ;
::ReleaseDC (m_hWnd, hdc) ;
wglDeleteContext(hglrc);
}

Everything works fine. Now I put OpenGL commands (setting up the scene and camera) enclosed by the same context stuff as in the OnPaint() function into other functions and nothing happens.

You should create your OpenGL context once and make it current (put it in OnCreate). Don't delete your OpenGL context until the app is done (put it in OnClose or OnDestroy). Put your drawing code in OnPaint (or have OnPaint call your drawing functions).

I changed my code the way you guys told me and it seems to work. I can execute OpenGL commands in other functions now. But there is another problem: From within the OnPaint() function I'm only able to change the background color of my OpenGL window. I cannot see the white rectangle which should be displayed now. What am I doing wrong now? Sorry for this stupid newbie question.



int COpenGL::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
if (CWnd::OnCreate(lpCreateStruct) == -1) return -1;
m_pCDC= new CClientDC(this);
MySetPixelFormat(m_pCDC->GetSafeHdc());
m_hRC = wglCreateContext(m_pCDC->GetSafeHdc());
wglMakeCurrent(m_pCDC->GetSafeHdc(), m_hRC);

glClearColor (0.0, 0.0, 0.0, 0.0);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0.0, 1.0, 0.0, 1.0, -1.0, 1.0);

return 0;
}

void COpenGL::OnPaint()
{
glClear (GL_COLOR_BUFFER_BIT);
glColor3f (1.0, 1.0, 1.0);
glBegin(GL_POLYGON);
glVertex3f (0.25, 0.25, 0.0);
glVertex3f (0.75, 0.25, 0.0);
glVertex3f (0.75, 0.75, 0.0);
glVertex3f (0.25, 0.75, 0.0);
glEnd();
glFlush();

SwapBuffers(m_pCDC->GetSafeHdc());
}

void COpenGL::OnDestroy()
{
wglMakeCurrent(NULL, NULL);
if (m_hRC!=NULL) ::wglDeleteContext(m_hRC);
if(m_pCDC) delete m_pCDC;
CWnd::OnDestroy();
}

Quote:Original post by Elsenhans2
int COpenGL::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
if (CWnd::OnCreate(lpCreateStruct) == -1) return -1;
m_pCDC= new CClientDC(this);
MySetPixelFormat(m_pCDC->GetSafeHdc());
m_hRC = wglCreateContext(m_pCDC->GetSafeHdc());
wglMakeCurrent(m_pCDC->GetSafeHdc(), m_hRC);

glClearColor (0.0, 0.0, 0.0, 0.0);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0.0, 1.0, 0.0, 1.0, -1.0, 1.0);

return 0;
}

Looks like you're not returning to the modelview stack after you set the projection.

It has nothing to do with returning to the modelview stack. I put these commands in and still I see just a black window. When I make the context current within OnPaint(), add the camera settings and delete the context after that everything works fine. Making the context current in OnCreate() and deleting it in OnDestroy() seems to have no effect. I can only change the background color but cannot see the white rectangle which should be displayed in the OpenGL window.