I am testing my game on a Mac with a resolution of 2560 x1600 and am getting some strange behaviour. The frame buffer size reported by glfwGetFramebufferSize is always 1650 x 1050, regardless of which resolution I set with glfwCreateWindow, or if I set GLFW_COCOA_RETINA_FRAMEBUFFER or not.
I do not understand why the frame buffer is 1650 x 1050. It should either be 2560x1600, or 1280 x 800 depending if retina is enabled.
The GLFW_COCOA_RETINA_FRAMEBUFFER setting seems to have no effect at all. The performance of the game is equally bad, if it’s enabled or disabled.
I only have macOS 10.13 and no retina display, so cannot investigate this issue myself. From what I recall there were changes in macOS 11+ which broke some features of GLFW, and this may be one of them.