Pinch and Scroll to Move and Zoom in Unity for Mobile Games

ScrollAndPinch.cs

/*

Set this on an empty game object positioned at (0,0,0) and attach your active camera.
The script only runs on mobile devices or the remote app.

*/

using UnityEngine;

class ScrollAndPinch : MonoBehaviour
{
#if UNITY_IOS || UNITY_ANDROID
    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);
    }
#endif
}

I noticed that the pinch and scroll take away the camera to out of bounds. This glitch makes the map out sight by totally zooming in or zooming out by the user, hence creating a situation to restart the app. If there is an add-on to prevent moving the camera out of specific area then it would have been a great script. The scroll and pinch features works well, though.

After the //scroll section you can add a few lines to keep the camera in your bounds.

After the //scroll section you can add a few lines to keep the camera in your bounds.

Can you please tell me what lines of code needs to be set to keep the camera in the bounds.

Can you help dont understand why not working

NullReferenceException: Object reference not set to an instance of an object
CameraControl.PlanePositionDelta (UnityEngine.Touch touch) (at Assets/CameraControl.cs:67)
CameraControl.Update () (at Assets/CameraControl.cs:30)

Can you help dont understand why not working

NullReferenceException: Object reference not set to an instance of an object
CameraControl.PlanePositionDelta (UnityEngine.Touch touch) (at Assets/CameraControl.cs:67)
CameraControl.Update () (at Assets/CameraControl.cs:30)

Have you referenced the camera and plane from the inspector ?

To anyone who wants to:

• Restrict the zoom in and out of the camera
• Adjust camera pan speed

Check out the fork that i made. I have added a few simple lines of code to do the above function.

Thanks for sharing this script @ditzel, it's very useful and helped me today a lot :) 🙏

You should know that someone out there is thinking good things about you today and wish you well! :D

@ditzel you are the best
@Kudoshi thanks for the great fork!