Camera shaking/jittering while moving it (No physics/rigidbodies)

Unity Engine
1

Hey so I’m working on a simple phone game but are having some really annoying problems with the camera moving fast between 2 points but I’m only changing the position once in my script. I’ve uploaded the project here for demonstration: https://dl.dropboxusercontent.com/u/13581369/SomethingIsNotRight/SomethingIsNotRight.html (Hold down button 0/LMB and move slowly)

My goal is to have smooth movement relative to the world when draging the mouse or finger on the phone. my very messy script so far:

using UnityEngine;
using System.Collections;

public class Swipe : MonoBehaviour
{
    // Use this for initialization
    void Start ()
    {
       Application.targetFrameRate = 60;
    }

    float speed = 0.1f;
    float zoomSpeed = 0.1f;
    float currDist = 0.0f;
    float lastDist = 0.0f;
    Vector3 LastPosition;
    Vector3 CurrentPosition;

    void FixedUpdate()
    {
        CurrentPosition = Camera.main.ScreenToWorldPoint(Input.mousePosition);
    }

    private void LateUpdate()
    {
       
        //Mobile
        //if (Application.platform == RuntimePlatform.Android || Application.platform == RuntimePlatform.IPhonePlayer)
        //{
            if (Input.touchCount == 1)
            {
                if (Input.GetTouch(0).phase == TouchPhase.Began)
                {
                    StopAllCoroutines();
                    flicktimer = 0;
                    CheckClick(Input.GetTouch(0).position);
                }
                else if (Input.GetTouch(0).phase == TouchPhase.Moved)
                {
                    this.transform.position += (Vector3)Input.touches[0].deltaPosition;
                }
                else if (Input.GetTouch(0).phase == TouchPhase.Ended)
                {
                    CheckClick(Input.GetTouch(0).position);
                    if (CheckFlick())
                    {
                        flickstart = this.transform.position;
                        flickend = this.transform.position;
                        flickend -= (Input.touches[0].deltaPosition * 0.0001f);
                        StartCoroutine(DoFlick());
                    }
                }
            }
            if (Input.touchCount == 2)
            {
                PinchZoom();
            }
        //}
        //PC
        //else if (Application.platform == RuntimePlatform.WindowsEditor)
        //{
            if (Input.GetMouseButtonDown(0))
            {
                StopAllCoroutines();
                CheckClick(Input.mousePosition);
            }
            else if (Input.GetMouseButton(0))
            {
                this.transform.position += (LastPosition - CurrentPosition);
            }
            else if (Input.GetMouseButtonUp(0))
            {
                CheckClick(Input.mousePosition);
                if (CheckFlick(CurrentPosition, LastPosition))
                {
                    flickstart = this.transform.position;
                    flickend = this.transform.position;
                    flickend -= (Vector2)((CurrentPosition - LastPosition) * 0.01f);
                    StartCoroutine(DoFlick());
                }
            }
            Zoom();
        //}
            LastPosition = CurrentPosition;
    }



    private bool CheckClick(Vector2 pos)
    {
        Vector3 wp = Camera.main.ScreenToWorldPoint(pos);
        Vector2 touchPos = new Vector2(wp.x, wp.y);
        var hit = Physics2D.OverlapPoint(touchPos);

        if (hit)
        {
            Debug.Log(hit.transform.gameObject.name);
            //hit.transform.gameObject.SendMessage('Clicked',0,SendMessageOptions.DontRequireReceiver);
            return true;
        }
        return false;
    }

    private bool CheckFlick()
    {
        Debug.Log((Input.touches[0].deltaPosition));
        return (Vector2.SqrMagnitude(Input.touches[0].deltaPosition) > 10);
    }

    private bool CheckFlick(Vector2 curpos, Vector2 lastpos)
    {
        Debug.Log(Vector2.SqrMagnitude(curpos - lastpos));
        return (Vector2.SqrMagnitude(curpos - lastpos) > 10);
    }

    private void PinchZoom()
    {
        Touch touchZero = Input.GetTouch(0);
        Touch touchOne = Input.GetTouch(1);

        // Find the position in the previous frame of each touch.
        Vector2 touchZeroPrevPos = touchZero.position - touchZero.deltaPosition;
        Vector2 touchOnePrevPos = touchOne.position - touchOne.deltaPosition;

        // Find the magnitude of the vector (the distance) between the touches in each frame.
        float prevTouchDeltaMag = (touchZeroPrevPos - touchOnePrevPos).magnitude;
        float touchDeltaMag = (touchZero.position - touchOne.position).magnitude;

        // Find the difference in the distances between each frame.
        float deltaMagnitudeDiff = prevTouchDeltaMag - touchDeltaMag;

        Debug.Log(deltaMagnitudeDiff);

        // ... change the orthographic size based on the change in distance between the touches.
        camera.orthographicSize += deltaMagnitudeDiff * 0.05f;

        // Make sure the orthographic size never drops below zero.
        camera.orthographicSize = Mathf.Max(camera.orthographicSize, 10f);
    }

    private void Zoom()
    {
        camera.orthographicSize += Input.GetAxis("Mouse ScrollWheel") * 30f;
        camera.orthographicSize = Mathf.Max(camera.orthographicSize, 10f);
    }


    private Vector2 flickstart;
    private Vector2 flickend;
    private float flicktime = 2;
    private float flicktimer = 0;
   
    private IEnumerator DoFlick()
    {
        while (flicktime >= flicktimer)
        {
            flicktimer += Time.deltaTime;
            transform.Translate(Vector2.Lerp(flickstart, flickend, flicktime) * Time.deltaTime);
            yield return new WaitForEndOfFrame();
        }
    }
}

I’ve also tried Lateupdate, and update but the shaking is even worse there :\

2

I made an even simpler version of the script; Same problem…

using UnityEngine;
using System.Collections;

public class Swipe : MonoBehaviour
{
    Vector2 LastPosition;
    Vector2 CurrentPosition;
    void Update()
    {
        LastPosition = CurrentPosition;

    }

    private void LateUpdate()
    {
        CurrentPosition = Camera.main.ScreenToWorldPoint(Input.mousePosition);
        if (Input.GetMouseButton(0))
        {
                Vector2 pos = (CurrentPosition - LastPosition);
                Debug.Log(pos);
                this.transform.position = new Vector3(this.transform.position.x - pos.x, this.transform.position.y - pos.y, -10);
        }
    }
}
3

I’ve found out what courses the strange behavior however I’m still unaware why it happens.

CurrentPosition =Camera.main.ScreenToWorldPoint(Input.mousePosition); // Flickering
CurrentPosition = Input.mousePosition; //Works - Smooth movement but doesn't move relative to the world
4

Okay I’ve fixed my issue but I’m still a bit confused about how that fixes it… The only logically explanation I can find is that it may be references that gets over written… If anyone can explain it I would gladly hear your assumptions:

Working Code:

public class Swipe : MonoBehaviour
{
    Vector2 LastPosition;
    Vector2 CurrentPosition;

    void FixedUpdate()
    {
    }

    void Update()
    {

    }

    private void LateUpdate()
    {
        CurrentPosition = -Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, Camera.main.nearClipPlane));

        if (Input.GetMouseButton(0))
        {
            Vector2 pos = (CurrentPosition - LastPosition);
            this.transform.position += new Vector3(pos.x, pos.y, 0);
        }

        LastPosition = -Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, Camera.main.nearClipPlane)); //This line was the problem LastPosition = CurrentPosition may have overwritten some values???
    }
}
5

Hi, I had the same issue and your post has helped me a lot… After changing LastPosition to directly Camera.ScreenToWorldPoint it works perfectly. No clue how, but it really works! Thanks a lot!