Ok, what I wanted to do was to make the crossbow scope have a nightvision lens, So the easiest way I thought of was to draw a green fade. This works great. But then I wanted to make everything bright. (Like what opposing force did with their NVG, they made the surrounding world brighter. And drew a green sprite over the screen, off course me, I'm using a green fade.)
Now but when I go to do this, In game I get an error that it can't change the gamma and brightness cvar. Here, I got two screenshots:
So please, can somebody help me, what am I missing!?