ex.1 without the double buffer in the current code the framerate isn't limited.(and fails down to a 3-5fps)
ex. 2. way back when you started with OpenGL if I compiled the code without the double buffer flag the screen would just be black.(Googling this says it is a Windows 10 issue, but I believe it got fixed with the glFlush() you just added.)
Without the double buffer flag I don't the code should work at all. I think it is pure random coincidence that it happens to work, and so we're only using it that way on the stream because for some reason it allows OBS to work. You should never
try to run it that way in any other circumstance.