So, I've got a problem after resizing window in mfc project. This is the code: void CCubeView::DrawGraphic() { CRect clientRect; GetClientRect(&clientRect); glViewport(0, 0, clientRect.right, clientRect.bottom); glMatrixMode(GL_PROJECTION); glOrtho(0,1,0,1,0,1); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glColor3f (1.0, 0.0, 0.5); glBegin(GL_LINES); glVertex3f( 0.5, 0.5, 0 ); //полезная область будет от 0 до 1 glVertex3f( 0 , 0, 0 ); glEnd(); } void CCubeView::OnDraw(CDC* pDC) { CCubeDoc* pDoc = GetDocument(); ASSERT_VALID(pDoc); glClearColor (0,0,0,0); glClear (GL_COLOR_BUFFER_BIT || GL_DEPTH_BUFFER_BIT); DrawGraphic(); SwapBuffers(pDC->m_hDC); } In the beginning of a program the line that is described in func DrawGraphic() is painted in a window. after calling a modal dialog in a program, function InvalidateRect(NULL,FALSE) is called. After calling invalidateRect the line isn't painted in a window. If there is a resizing in a program (I think this way the func InvalidateRect is called aswell) the line isn't painted too. What it can be?

Yes, I use debug and the func is called. So,sth wrong happens during InvalidateRect(...). what is think outside the box? it's just like to take coffe and do sth else while thinking over the problem?

The problem with MFC (in this case with Opengl) is the need to become familiar/intimate with how/when the messaging system works to update various elements (i.e what happens without ensuring a message is sent to do something (i.e. system will send message(s) automagically) and when you need to explicitly send a message to make something happen.

There are few ways to deal with this problem. Typically I have found many examples of/and use the CWnd::RecalcLayout() function (but typically when the state of something in a CCubeView needs to be updated/changed). [Google on
CWnd::RecalcLayout() for more info].

In your case I would try CCubeView::RecalcLayout() from within or
at sometime after the dialog has finished doing what it does: it should put your
CCubeView back into the reasonable state it was in before the dialog was put into action.

Try it a see. If it helps, then good I guess.
But you may also want to take a minimalist's approach and substitute it for any other better solutions (e.g. performance wise?) that may come along/be recommended (depending on the nature of your app).

void CCubeView::DrawGraphic()
{
// ...

// the last two parameters of glViewport() are
// widith and height of your view port.
glViewport(0, 0, clientRect.width(), clientRect.height());

// ...
}


void CCubeView::OnDraw(CDC* pDC)
{
// insert this line before you draw with OpenGL
// m_hGLContext is the OpenGL context
wglMakeCurrent(pDC->m_hDC,m_hGLContext);


// your drawing code
// ...
}