Calculating Camera FOV based on Object's position

Unity Engine
1

Hello all,

I made a simple script to adjust the camera’s FOV depending on where the lowest object in my scene is located along the Z axis. Here is my code :

    private Camera _camera;
        private float _fov, _currentVelocity = 0.0f, _smoothTime = 0.3f;
        private Vector3 _objPos;
   
        public float padding = 1.0f;
   
        private void Start()
        {
            _camera = GetComponent<Camera>();
        }
       
        private void Update()
        {
            _camera.fieldOfView = Mathf.SmoothDamp(_camera.fieldOfView, _fov, ref _currentVelocity, _smoothTime);
        }
   
        public void SetFov()
        {
            var theta = Mathf.Atan2(_camera.transform.position.z - _objPos.z - padding, _camera.transform.position.y) * Mathf.Rad2Deg;
            var camRot = _camera.transform.localEulerAngles.x;
            _fov = -2 * (theta - camRot);
        }
   
        public void SetObjectPosition(Vector3 pos)
        {
            _objPos = pos;
        }

So I am trying to calculate the FOV angle relative to the distance between the camera and the beginning of the camera viewport. Here is a diagram to illustrate this :

360×640 256 KB

I am sure I made a silly mistake somewhere, would really appreciate it if someone could point it out for me.

Thanks.

2

Nevermind, I figured it out. I forgot to consider the orientation of the angles. Here is the fixed line of code for anyone who is interested :

_fov = Mathf.DeltaAngle(-2 * (theta + camRot - 90.0f), 90.0f);