in the old 2.7 version I had no problem with the hires retina display of the macbook pro. In the new 3.0 version my 640 x 400 pixel application starts with the viewport in the lower left corner. As soon as I touch the window bar the viewport spreads to the full window. This happens not clearly reproducable and the viewport drops back some times to the quater window size. I tried both glfwSetWindowSizeCallback and glfwSetFramebufferSizeCallback. What kind of events do I have to listen to?
Thanks for any help.
You should set the viewport to the framebuffer size (which is in pixels) instead of the window size (which is in screen coordinates). OpenGL works with pixels, not screen coordinates.