glvertex3f to dark

what could make my glvertex3f to dark and how to fix? In some ways it’s ok but somewhere else to dark. It’s within X-Plane so I guess they’re doing something I need to work against.

Your best bet is to talk to the X-Plane support guys on their development forum. The answer is almost certainly going to depend on how X-Plane is written, how materials and other render state are managed, and which method you’re using to plug external OpenGL code into their system).