IOS zoom to touch position and clamp

Hi,

Currently, I have 2 questions here and wonder if anyone can help me. Thanks!

1. I have trouble to make camera pinch zoom to touch position. 2

2. I did a Mathf.clamp to limit the camera X and Y axis, however, it is very jaggy.

so here is my script. It does nice pinch to zoom and pan around while touch drag.

if(Input.touchCount == 2)

{

curDist = Input.GetTouch(0).position - Input.GetTouch(1).position;

preDist =((Input.GetTouch(0).position - Input.GetTouch(0).deltaPosition) - (Input.GetTouch(1).position - Input.GetTouch(1).deltaPosition)); touchDelta = curDist.magnitude - prevDist.magnitude;

Vector2 touch_pos = Input.GetTouch(0).deltaPosition/2;

//Drag Camera with 2 fingers.

transform.Translate((-touch_pos.x/dragSpeed) Camera.fieldOfView/2.5f), (-touch_pos.y/dragSpeed) Camera.fieldOfView/2.5f, 0f);

//Zoom

Camera.main.FieldOfView = Mathf.Clamp(Camera.main.fieldOfView - (0.1f * touchDelta), 20,60);

//Zoom to touch position (DIDN"T WORK!!!!!)

transform.position = Vector3.MoveTowards(transform.position, new Vector3(touch_pos.x, touch_pos.y, transform.position.z), 60 * Time.deltaTime);

//Clamp Camera.

transform.position = new Vector3(Mathf.Clamp(transform.position.x, -clampX, clampX),Mathf.Clamp(transform.position.y, -clampY, clampY),transform.position.z;

}

//Drag Camera with 1 finger.

if(Input.touchCount >= 1 && Input.touchCount <2)

{

Vector2 touch_pos = Input.GetTouch(0).deltaPosition/2;

transform.Translate((-touch_pos.x/dragSpeed) Camera.fieldOfView/2.5f), (-touch_pos.y/dragSpeed) Camera.fieldOfView/2.5f, 0f);

}

//Clamp Camera again (but still not smooth).

transform.position = new Vector3(Mathf.Clamp(transform.position.x, -clampX, clampX),Mathf.Clamp(transform.position.y, -clampY, clampY),transform.position.z;

your help will be appreciated. Thank you

Jason