Spinning an object using touch input

Hello!

I made this C# script. I think this is the easiest way to spin an object. Simply attach it to your object and it will spin while drag, and when you release the spin will slow down.

 using UnityEngine;
 using System.Collections;
 
 public class SpinLogic : MonoBehaviour {
 
     float f_lastX = 0.0f;
     float f_difX = 0.5f;
     float f_steps = 0.0f;
     int i_direction = 1;
 
     // Use this for initialization
     void Start () 
     {
         
     }
     
     // Update is called once per frame
     void Update () 
     {
         if (Input.GetMouseButtonDown(0))
         {
             f_difX = 0.0f;
         }
         else if (Input.GetMouseButton(0))
         {
             f_difX = Mathf.Abs(f_lastX - Input.GetAxis ("Mouse X"));
 
             if (f_lastX < Input.GetAxis ("Mouse X"))
             {
                 i_direction = -1;
                 transform.Rotate(Vector3.up, -f_difX);
             }
 
             if (f_lastX > Input.GetAxis ("Mouse X"))
             {
                 i_direction = 1;
                 transform.Rotate(Vector3.up, f_difX);
             }
 
             f_lastX = -Input.GetAxis ("Mouse X");
         }
         else 
         {
             if (f_difX > 0.5f) f_difX -= 0.05f;
             if (f_difX < 0.5f) f_difX += 0.05f;
 
             transform.Rotate(Vector3.up, f_difX * i_direction);
         }
     }
 }

I hope it helps!

Happy Coding!

Ok I found the original clean and beautiful code (from user duck) that I brutally butchered with the finesse of a drunk rhino above. Thinking about it i really wish i posted this in response to the thread i found ducks example in:

http://answers.unity3d.com/questions/34317/rotate-object-with-mouse-cursor-that-slows-down-on.html

I'm basically trying to make this work as well as it does with a mouse but with fingers on a touchscreen with no unexpected issues with potentially multiple fingers touching and releasing in the heat of action. Should be a simple conversion job, but for me it is turning into a real nightmare. I feel so stupid right now. Please don't think I'm some script kiddie that wants something for free without working for it. I literally can't get my head around what may be wrong and have spent 2 full days on this tweaking/rebuilding/failing/starting over/coming back/swearing etc. This motion working properly and reliably is the only thing holding me back and it is the main action for my game so it needs to be as efficient as possible. Thanks so much for any help, suggestions or if you must negative comments ;-)

 var rotationSpeed = 10.0;
 var lerpSpeed = 1.0;
 
 private var speed = new Vector3();
 private var avgSpeed = new Vector3();
 private var dragging = false;
 private var targetSpeedX = new Vector3();
 
 function OnMouseDown() 
 {
     dragging = true;
 }
 
 function Update () 
 {
 
     if (Input.GetMouseButton(0) && dragging) {
         speed = new Vector3(-Input.GetAxis ("Mouse X"), Input.GetAxis("Mouse Y"), 0);
         avgSpeed = Vector3.Lerp(avgSpeed,speed,Time.deltaTime * 5);
     } else {
         if (dragging) {
             speed = avgSpeed;
             dragging = false;
         }
         var i = Time.deltaTime * lerpSpeed;
         speed = Vector3.Lerp( speed, Vector3.zero, i);   
     }
 
     transform.Rotate( Camera.main.transform.up * speed.x * rotationSpeed, Space.World );
     transform.Rotate( Camera.main.transform.right * speed.y * rotationSpeed, Space.World );
 
 }

Here's my version that uses physics and touch input from a mobile device if it can help anyone

 using UnityEngine;
 using System.Collections;
 
 public class SpinWithTouch : MonoBehaviour
 {
     public Rigidbody rb;
 
     void Start()
     {
         rb = GetComponent<Rigidbody>();
     }
 
     void Update()
     {
         if (Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Moved)
         {
             // Get movement of the finger since last frame
             Vector2 touchDeltaPosition = Input.GetTouch(0).deltaPosition;
 
             rb.AddTorque(Camera.main.transform.up * -touchDeltaPosition.x);
             rb.AddTorque(Camera.main.transform.right * touchDeltaPosition.y);
         }
     }
 }
 

Following @stek very simple and very helpful example. I took his code and modified it so it can spin on both sides while accepting touch controls so it can work on mobile devices. Simply, attach the script to the spinning object. Bare with me, i am a beginner. The script:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;


 public class SpinWheelScript : MonoBehaviour {


 float pointerY;
 float f_lastX = 0.0f;
 float f_difX = 0.5f;
 float f_steps = 0.0f;
 int i_direction = 1;


 void Start()
 {
     pointerY = Input.GetAxis("Mouse Y");
 }

 void Update()
 {

     if (Input.GetMouseButtonDown(0))
     {
         f_difX = 0.0f;
     }


     else if (Input.touchCount > 0)
     {
         pointerY = Input.touches[0].deltaPosition.y;
         f_difX = Mathf.Abs(f_lastX - pointerY);
         var touch = Input.GetTouch(0);

         if (touch.position.x > Screen.width / 2)
         {
             // Right
             if (f_lastX < Input.GetAxis("Mouse Y"))
             {
                 i_direction = 1;
                 transform.Rotate(Vector3.forward, f_difX * Time.deltaTime);
             }

             if (f_lastX > Input.GetAxis("Mouse Y"))
             {
                 i_direction = -1;
                 transform.Rotate(Vector3.forward, -f_difX * Time.deltaTime);
             }
         }
         else if (touch.position.x < Screen.width / 2)
         {
             // Left
             if (f_lastX < Input.GetAxis("Mouse Y"))
             {
                 i_direction = -1;
                 transform.Rotate(Vector3.forward, -f_difX * Time.deltaTime);
             }

             if (f_lastX > Input.GetAxis("Mouse Y"))
             {
                 i_direction = 1;
                 transform.Rotate(Vector3.forward, f_difX * Time.deltaTime);
             }
         }

         f_lastX = -pointerY;
         f_difX = 500f;
     Debug.Log(f_difX);
     }
     else
     {
         if (f_difX > 0.5f) f_difX -= 1f;
         if (f_difX < 0.5f) f_difX += 1f;

         transform.Rotate(Vector3.forward, f_difX * i_direction * Time.smoothDeltaTime);
     }
 }
 }

Currently, the object will spin based on a swipe along the Y axis, you can simple change it by replacing the Y's with X's. Also, i've modified the speeds to fit my liking. Hope this helps.

Cheers!

I don't know if anyone else needs this. But in my case I didn't want the object to rotate, but rather rotate the camera around it, so this is the script I made (for mobile), in case anyone else wants something similar. (The swiper object is an empty gameobject which is the parent of the camera. I didn't include code to change the swiper transform to match the object since I only use one object, but that should be easy to add if you need to rotate many different things). cheers :)

 using UnityEngine;
 using UnityEngine.EventSystems;
 
 public class Rotator : MonoBehaviour, IDragHandler
 {
     public Transform world;
     public GameObject swiper;
     public float zoomSpeed;
     float direction;
 
     public void OnDrag(PointerEventData eventData)
     {
         if (Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Moved)
         {
 
             // Get movement of the finger since last frame
             Vector2 touchDeltaPosition = Input.GetTouch(0).deltaPosition;
 
             //actual touch
             Touch touchZero = Input.GetTouch(0);
             //current touch x position
             float touchZeroCurrPos = touchZero.position.x;
             //previous touch x position
             float touchZeroPrevPos = touchZero.position.x - touchDeltaPosition.x;
             //difference between previous and current finger position
             float Diff = touchZeroPrevPos - touchZeroCurrPos;
 
            
             if (touchZeroCurrPos < touchZeroPrevPos )
             {
                 Debug.Log("right");
                 direction = -1;
                 swiper.transform.Rotate(Vector3.up, -Diff * Time.deltaTime * zoomSpeed);
             }
             if (touchZeroCurrPos > touchZeroPrevPos)
             {
                 Debug.Log("left");
                 direction = 1;
                 swiper.transform.Rotate(Vector3.down, Diff * Time.deltaTime * zoomSpeed);
             }
 
         }
     }
 }