Question Rotate Bar Based on Touch Drag

I want to rotate the bar based on my finger touch draw related to the pivot point. Following test structure implementation, I have created it for testing purposes.


Currently, I can able to write this code:

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class TestRotateController : MonoBehaviour
6. {
7.  
8.     float rotateSpeed = 10f;
9.     Vector2 touchStartPos;
10.     Transform touchItem;
11.     //
12.     [SerializeField] LayerMask touchItemsMask;
13.  
14.     private void Update()
15.     {
16.         if (Input.GetMouseButtonDown(0))
17.         {
18.             Vector3 mousePos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
19.             Vector2 mousePos2D = new Vector2(mousePos.x, mousePos.y);
20.  
21.             RaycastHit2D hit = Physics2D.Raycast(mousePos2D, Vector2.zero, 0f, touchItemsMask);
22.  
23.             if (hit.collider != null && hit.transform.CompareTag(GameConstants.TAG_RELEASE_ANGLE_BAR))
24.             {
25.                 touchItem = hit.transform;
26.                 touchStartPos = mousePos2D;
27.             }
28.         }
29.         else if (Input.GetMouseButton(0))
30.         {
31.  
32.             if (touchItem != null && touchItem.CompareTag(GameConstants.TAG_RELEASE_ANGLE_BAR))
33.             {
34.  
35.                 Vector3 mousePos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
36.                 Vector2 mousePos2D = new Vector2(mousePos.x, mousePos.y);
37.  
38.                 RotateReleaseAngleBar(touchStartPos, mousePos2D);
39.  
40.             }
41.         }
42.         else if (Input.GetMouseButtonUp(0))
43.         {
44.             touchItem = null;
45.         }
46.     }
47.  
48.     // rotate pivot parent
49.     public void RotateReleaseAngleBar(Vector2 touchStartPosition, Vector2 touchPosition)
50.     {
51.         if (touchStartPosition.x > touchPosition.x)
52.         {
53.             transform.parent.Rotate(Vector3.forward, rotateSpeed * Time.deltaTime);
54.         }
55.         else if (touchStartPosition.x < touchPosition.x)
56.         {
57.             transform.parent.Rotate(Vector3.forward, -rotateSpeed * Time.deltaTime);
58.         }
59.     }
60. }

Now with this code, I can't able to rotate the bar as my finger is moving. The selected direction will remain proper because I have used X value to decide this but when I stop dragging my finger then also rotation remains to continue in the same direction.

I want to stop this, I want to rotate the bar based on finger drag amount. It is a kind of experience, I want a person is rotating the bar with his finger.

 

Is this the type of thing you are looking for?

If so, here is the script I came up with:

Code (CSharp):

1. using UnityEngine;
2.  
3. public class TestRotateController : MonoBehaviour
4. {
5.     [SerializeField] private Collider2D m_Handle;
6.     private Quaternion? m_RotationOffset;
7.  
8.     private void Update()
9.     {
10.  
11.         if (Input.GetMouseButtonDown(0))
12.         {
13.             Vector2 mousePos = GetMousePosition();
14.             // Is mouse inside handle collider?
15.             if (m_Handle.OverlapPoint(mousePos))
16.                 // Get offset rotation between up vector and mousePos
17.                 m_RotationOffset = Quaternion.FromToRotation(GetDirectionFromPoint(mousePos), transform.up);
18.         }
19.         else if (Input.GetMouseButtonUp(0))
20.             m_RotationOffset = null;
21.  
22.         // If rotation offset is not null, do rotation
23.         if (m_RotationOffset != null)
24.         {
25.             // Debug draw offset rotation, no needed.
26.             Debug.DrawLine(transform.position, transform.position + Quaternion.Inverse(m_RotationOffset.Value) * transform.up, Color.cyan);
27.             // Look at cursor
28.             transform.rotation = Quaternion.LookRotation(Vector3.forward, GetDirectionFromPoint(GetMousePosition()));
29.             // Apply offset rotation
30.             transform.rotation *= m_RotationOffset.Value;
31.         }
32.     }
33.  
34.     private Vector2 GetMousePosition() => Camera.main.ScreenToWorldPoint(Input.mousePosition);
35.     private Vector2 GetDirectionFromPoint(Vector2 point) => point - (Vector2)transform.position;
36. }

Instead of you raycasting, I just check if the cursor overlaps the handle collider defined in the inspector. Of course raycasting is still a valid option, especially if you want a foreground object to block the interaction.