How to rotate camera around a chosen point?

Alright, so someone else asked this question a long time ago but couldn’t explain what they were wanting to know and therefore never got an answer. So I’ll explain it as clearly as possible.
I have a point in space (the location of a unit in a space RTS game). I want the camera to remain a fixed distance from this point (say 30 units). However, when clicking and dragging, I want the camera to rotate around this point, while continuing to look at the point. I more or less just need to know how to get the mouse’s movement and turn it into the resources needed for the FlyByCamera.class’s rotateCamera(float value, Vector3f axis) method.
How would I get “value” and “axis?” If I can figure that out, I can get the rest from there pretty simply.

checking out how the chase camera does it may be a good start.

I would rotate a vector sticking out 30 units in z direction by a quaternion for the position, and use that same quaternion to rotate the camera locally

…and you do not want to bother FlyByCamera with this information. When dragging, you have an angle and a distance… calculating position and orientation from this is easy and you can apply it to the camera directly. No reason to involve FlyByCamera… even if you want to continue flying around afterwards.

@pspeed You’re misunderstanding the reason I used FlyByCamera as an example. I’m simply saying the “rotateCamera” method in said class does exactly what I need, excluding a couple of modifications.
@wezrule I’ll have to look at it. Does it support mouse dragging to rotate around a point?

yep

@wezrule Actually, ChaseCamera is working perfectly as needed. I’d completely forgotten about it being there, and last I knew (or thought I knew), it only support WASD to rotate around the chosen spatial. Thanks!