I wonder what is the 3rd vector (the 3rd row) in the following code?
gluLookAt( -512, -384, 700, 512, 384, 0, 0.0f, 1.0f, 0.0f);
It is strange that if the first row is 512, 384, (the camera’s location), then I see the target as if I am standing with my eyes right on top of the desk’s surface, but if I change it to -512, -384, that means I walked away to the lower left side of the desk and look down the floor?.. or look at the desk? I thought the 3rd row tells how the camera is facing… so if I walk away from the desk and still face the same orientation, I should see the floor. So what is the third row anyway and how does it work?