Bounds to Orthographic Fitting equalvant for Perspective Camera

Unity Engine
1

Hi there,

I’m using following code from this place for Othographic camera to which works great

void Fit () {
        float screenRatio = (float)Screen.width / (float)Screen.height;
        float targetRatio = rink.bounds.size.x / rink.bounds.size.y;

        if(screenRatio >= targetRatio){
            Camera.main.orthographicSize = rink.bounds.size.y / 2;
        }else{
            float differenceInSize = targetRatio / screenRatio;
            Camera.main.orthographicSize = rink.bounds.size.y / 2 * differenceInSize;
        }
    }

However, now i want to get the same effect using perspective camera. Just like above code camera will not move.

Please advise
Thanks

2

If you calculate the height and distance to the target, the FOV is;

var fov = 2f * Mathf.Atan(targetHeight * 0.5f / targetDistance) * Mathf.Rad2Deg;

2 Likes
3

Thanks @grizzly for the assistance.

So targetHieght’d be rink.bounds.size.y?
and distance’d be like this?
Vector3.Distance(Camera.main.transform.position, rink.transform.position);

So final code’d be

var targetDistance = Vector3.Distance(Camera.main.transform.position, rink.transform.position);
var targetHeight = rink.bounds.size.y;
var fov = 2f * Mathf.Atan(targetHeight * 0.5f / targetDistance) * Mathf.Rad2Deg;

Is this right?

4

Yes, the frustum height should match the bounds height.