How to make OpenTK.GLControl Transparent

Question

I am using WPF and OpenTk and I have a GLControl that is set to Transparent, the clear color is set to Transparent as well but when it draws the rectangle it becomes black. How do I make it so that it draws my rectangle on a transparent background, I have stuff behind the OpenTK.GLControl that I want to see along with the rectangle.

Answer 1

Your OpenGL windows are regular Win32 windows. They do not work with WPF's "I can't believe it's not a window" windows. You can't make an OpenGL window transparent in the way you want.