Hi @Pulzer,
Welcome to the GLFW forums.
It looks like you forgot to set the glViewport. You need to set this to the framebuffer size.
EDIT: looking at the code further it appears you’ve not given enough of the code to know what’s going on, so it may not be the viewport size. Indeed that would normally show up as only part of the screen being rendered, so I’m not sure what’s going on here.
Cheers,
Doug.