Small extension to OrbitControls to allow for offsetting the target position on screen. This is useful for zooming and rotating around an arbitrary point on the screen to create model viewers with offset on screen. It also allows for panning around without changing the target position.
Live Demo: https://repalash.com/OffsetOrbitControls/
To use replace OrbitControls with OffsetOrbitControls and call controls.update() in the render loop. see index.html
To reset the target or to set the offset on the screen, set controls.targetOffset.set(x, y, 0) in screen space NDC.
To fix the target offset on screen, disable panning by doing controls.enablePan = false