I really hate to ask another question, but 3D is just killing me here. And as well, I made another thread for this since it is a completely different question regarding gluLookAt. I now have gluLookAt working, to some extent, but I am ending up with what seems like a angle-lock type deal, as well as another issue. I am as usual absolutely stumped. Here's a image I made demonstrating my problem.

Basically, what is going on, is I have gluLookAt code like so:
GLU.gluLookAt(width/2 + x, height/2, 80 + z, width/2 + x + rotx, height/2, 0, 0, 1f, 0);
And as you can see, I rotate the screen by adding rotx to the position the camera is looking at. The issue is, after just about that red section I have marked out, rotx has already surpassed 360, which to what I'm attempting should mean it has done a full turn, but for some reason that is not the case, and as well, after rotx gets high enough, the camera stops turning completely. I have no idea what is going on here, and help on this matter would be appriciated. Thanks.