How add limit to camera movement?

Questions & Answers
1

public Camera Camera;
public bool Rotate;
protected Plane Plane;

private void Awake()
{
    if (Camera == null)
        Camera = Camera.main;
}

private void Update()
{

    //Update Plane
    if (Input.touchCount >= 1)
        Plane.SetNormalAndPosition(transform.up, transform.position);

    var Delta1 = Vector3.zero;
    var Delta2 = Vector3.zero;

    //Scroll
    if (Input.touchCount >= 1)
    {
        Delta1 = PlanePositionDelta(Input.GetTouch(0));
        if (Input.GetTouch(0).phase == TouchPhase.Moved)
            Camera.transform.Translate(Delta1, Space.World);
    }

    //Pinch
    if (Input.touchCount >= 2)
    {
        var pos1  = PlanePosition(Input.GetTouch(0).position);
        var pos2  = PlanePosition(Input.GetTouch(1).position);
        var pos1b = PlanePosition(Input.GetTouch(0).position - Input.GetTouch(0).deltaPosition);
        var pos2b = PlanePosition(Input.GetTouch(1).position - Input.GetTouch(1).deltaPosition);

        //calc zoom
        var zoom = Vector3.Distance(pos1, pos2) /
                   Vector3.Distance(pos1b, pos2b);

        //edge case
        if (zoom == 0 || zoom > 10)
            return;

        //Move cam amount the mid ray
        Camera.transform.position = Vector3.LerpUnclamped(pos1, Camera.transform.position, 1 / zoom);

        if (Rotate && pos2b != pos2)
            Camera.transform.RotateAround(pos1, Plane.normal, Vector3.SignedAngle(pos2 - pos1, pos2b - pos1b, Plane.normal));
    }

}

protected Vector3 PlanePositionDelta(Touch touch)
{
    //not moved
    if (touch.phase != TouchPhase.Moved)
        return Vector3.zero;

    //delta
    var rayBefore = Camera.ScreenPointToRay(touch.position - touch.deltaPosition);
    var rayNow = Camera.ScreenPointToRay(touch.position);
    if (Plane.Raycast(rayBefore, out var enterBefore) && Plane.Raycast(rayNow, out var enterNow))
        return rayBefore.GetPoint(enterBefore) - rayNow.GetPoint(enterNow);

    //not on plane
    return Vector3.zero;
}

protected Vector3 PlanePosition(Vector2 screenPos)
{
    //position
    var rayNow = Camera.ScreenPointToRay(screenPos);
    if (Plane.Raycast(rayNow, out var enterNow))
        return rayNow.GetPoint(enterNow);

    return Vector3.zero;
}

private void OnDrawGizmos()
{
    Gizmos.DrawLine(transform.position, transform.position + transform.up);
}

,
public Camera Camera;
public bool Rotate;
protected Plane Plane;

private void Awake()
{
    if (Camera == null)
        Camera = Camera.main;
}

private void Update()
{

    //Update Plane
    if (Input.touchCount >= 1)
        Plane.SetNormalAndPosition(transform.up, transform.position);

    var Delta1 = Vector3.zero;
    var Delta2 = Vector3.zero;

    //Scroll
    if (Input.touchCount >= 1)
    {
        Delta1 = PlanePositionDelta(Input.GetTouch(0));
        if (Input.GetTouch(0).phase == TouchPhase.Moved)
            Camera.transform.Translate(Delta1, Space.World);
    }

    //Pinch
    if (Input.touchCount >= 2)
    {
        var pos1  = PlanePosition(Input.GetTouch(0).position);
        var pos2  = PlanePosition(Input.GetTouch(1).position);
        var pos1b = PlanePosition(Input.GetTouch(0).position - Input.GetTouch(0).deltaPosition);
        var pos2b = PlanePosition(Input.GetTouch(1).position - Input.GetTouch(1).deltaPosition);

        //calc zoom
        var zoom = Vector3.Distance(pos1, pos2) /
                   Vector3.Distance(pos1b, pos2b);

        //edge case
        if (zoom == 0 || zoom > 10)
            return;

        //Move cam amount the mid ray
        Camera.transform.position = Vector3.LerpUnclamped(pos1, Camera.transform.position, 1 / zoom);

        if (Rotate && pos2b != pos2)
            Camera.transform.RotateAround(pos1, Plane.normal, Vector3.SignedAngle(pos2 - pos1, pos2b - pos1b, Plane.normal));
    }

}

protected Vector3 PlanePositionDelta(Touch touch)
{
    //not moved
    if (touch.phase != TouchPhase.Moved)
        return Vector3.zero;

    //delta
    var rayBefore = Camera.ScreenPointToRay(touch.position - touch.deltaPosition);
    var rayNow = Camera.ScreenPointToRay(touch.position);
    if (Plane.Raycast(rayBefore, out var enterBefore) && Plane.Raycast(rayNow, out var enterNow))
        return rayBefore.GetPoint(enterBefore) - rayNow.GetPoint(enterNow);

    //not on plane
    return Vector3.zero;
}

protected Vector3 PlanePosition(Vector2 screenPos)
{
    //position
    var rayNow = Camera.ScreenPointToRay(screenPos);
    if (Plane.Raycast(rayNow, out var enterNow))
        return rayNow.GetPoint(enterNow);

    return Vector3.zero;
}

private void OnDrawGizmos()
{
    Gizmos.DrawLine(transform.position, transform.position + transform.up);
}
2

If you’re asking how to limit the camera to a certain area, just check if the camera is on the border or past the wanted area, and then reset its position to the border. A little clunky, but it could work.

3

What exactly should be limited?

Position? Then you can try this:

transform.position = new Vector3(
    Mathf.Clamp(transform.position.x, YourMinX, YourMaxX),
    Mathf.Clamp(transform.position.y, YourMinY, YourMaxY),
    Mathf.Clamp(transform.position.z, YourMinZ, YourMaxZ));