My variable changes after my gameobject moves, when there is no input to change the variable - unity3d

Question

I'm trying to get the last position of my gameobject, before it stops moving, but the "lastPos" variable keeps being magically changed to the current position, after my gameobject moves. (I'm probs being stupid)
The reason I'm doing this is to try to add smoothing to the end of the movement of my gameobject, instead of stopping suddenly after it being let go, I want it to gradually slide to a stop. So I was thinking if I found the difference between last position before it stops and the current one, I could add some velocity to the end of it, depending on the distance between the two points, the more velocity it would add.
I couldn't find a tutorial on how to add this.
The problem is probably in the last 3 If statements.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Move : MonoBehaviour
{
bool dragging = false;
Vector2 offset;
Transform toDrag;
Transform lastPos;
float posDif;
private void Start()
{
Application.targetFrameRate = 60;
}
void Update()
{
Vector2 v2;
if(Input.touchCount != 1)
{
dragging = false;
return;
}
Touch touch = Input.touches[0];
Vector2 pos = touch.position;
if(touch.phase == TouchPhase.Began)
{
toDrag = gameObject.transform;
v2 = new Vector2(pos.x, pos.y);
v2 = Camera.main.ScreenToWorldPoint(v2);
offset.x = toDrag.position.x - v2.x; offset.y = toDrag.position.y - v2.y;
dragging = true;
Debug.Log("TOUCH");
}
if (dragging && touch.phase == TouchPhase.Moved)
{
if (touch.phase != TouchPhase.Stationary && touch.phase != TouchPhase.Ended && touch.phase != TouchPhase.Canceled)
{
lastPos = gameObject.transform;
}
v2 = new Vector2(Input.mousePosition.x, Input.mousePosition.y);
v2 = Camera.main.ScreenToWorldPoint(v2);
toDrag.position = v2 + offset;
gameObject.transform.position = new Vector2(v2.x + offset.x, -2.67f);
Debug.Log("Last Pos: " + lastPos.position.x);
}
if (dragging && (touch.phase == TouchPhase.Ended || touch.phase == TouchPhase.Canceled))
{
dragging = false;
posDif = gameObject.transform.position.x - lastPos.position.x;
gameObject.GetComponent<Rigidbody2D>().velocity = new Vector2(posDif * 10f, 0f);
Debug.Log("Current Pos: " + gameObject.transform.position.x);
Debug.Log(posDif);
}
}
}

Answer 1

Your lastPos is set to your current gameObject transform. It’s a class, so a reference object, so you’ll always have the latest values.
If you change the type of the lastPos variable to be a Vector3 you’ll be storing that value, at the time you record it. transform.position is a Vector3 which is a struct (a value type).
...
private Vector3 lastPos;
...
if (dragging && touch.phase == TouchPhase.Moved)
{
lastPos = gameObject.transform.position;
v2 = new Vector2(Input.mousePosition.x, Input.mousePosition.y);
v2 = Camera.main.ScreenToWorldPoint(v2);
toDrag.position = v2 + offset;
gameObject.transform.position = new Vector2(v2.x + offset.x, -2.67f);
Debug.Log("Last Pos: " + lastPos);
}
If what I’m talking about sounds alien, here’s the official docs at Microsoft describing the difference between structs (value types) and classes (reference types). Choosing Between Class and Struct