Rotating a gameobject via dragging finger

I've never tried to do t$$anonymous$$s myself, but I can take a guess at it. Maybe try somet$$anonymous$$ng like t$$anonymous$$s:

 Vector2 firstScreenPosition;
 
 Vector2 secondScreenPosition;
 
 bool fingerDownBool;
 
 void Start()
 {
 fingerDownBool = false;
 }
 
 void Update()
 {
 
 if (Input.GetButtonDown ("Fire1"))
         {
 if (fingerDownBool == false)
 {
 fingerDownBool = true;
 
 //t$$anonymous$$s part I'm guessing on if it works for your specific example since haven't tried it
 firstScreenPosition = mainCam.WorldToScreenPoint(Input.mousePosition);
 }

 

    //probably want a better way to detect if finger is up t$$anonymous$$s might require 2 clicks to start moving

 //could try GetButtonUp() for example

   

  else if (fingerDownBool == true)
     {

 fingerDownBool = false;
 }
 }
 
 
 if (fingerDownBool == true)
 {
 secondScreenPosition = mainCam.WorldToScreenPoint(Input.mousePosition);
 
 if (secondScreenPosition.x >= firstScreenPosition.x)
 {
 float newScreenPosition = secondScreenPosition.x - firstScreenPosition.x;
 
 //probably want to use a Slerp or some other function for smooth rotation but you get the idea
 transform.RotateAround (transform.position, transform.up, newScreenPosition);
 }
 
 //etc
 else if (secondScreenPosition.x <= firstScreenPosition.x)
 {
 }
 
 //grab current position for next Update()comparison
 
 firstScreenPosition = mainCam.WorldToScreenPoint(Input.mousePosition);
 
 }

Hopefully that get's you started that is a complete guess since I never tried it, but maybe get you on the right track I hope.