OPENGL and MFC CDC
I wrote a pretty big graphics program a while back that uses CDC for drawing.
I wanted to do some 3D stuff among dozens of other things so, i installed OPENGL in replace of my CDCs
I have more everything ironed out and its working great for the most part.
My mouse points and any other point (example - ::OnMouseMove(nFlags, point)) are not 100% matching up with what OPENGL draws.
For example, if you want to draw a line the further you go out from point 0,0 the bigger the difference in the mouse point and where it draws when you click.
So if you draw a long from 0,0 to say 200,200 then it seems to draw properly. However, the more i zoom out the more the difference is visible.
Im assuming its in my projection.... i really don't know. Im not sure what code to give you.
Note, my ASPECT is 1 because i need to be able to change the size of the window and i don't want the image to lose that same aspect.
// Make the rendering context current
// Reset The Current Viewport And Perspective Transformation
glViewport(0, 0, cx, cy);
m_width = cx;
// Calculate The Aspect Ratio Of The Window