Question How to get smooth inertia scrolling on a scroll rect with a mouse scroll wheel?

Hi,

is there a way to get the same inertia behavior on a scroll rect that you get when click-dragging the list,
when you use a mouse scroll wheel? The scroll wheel just moves the list without any smoothing.

Thanks!

 

Ok, with the help of my boy OpenAI Chatbot I came up with this. Works pretty well. You can use this script to replace the regular Scroll Rect script.

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEngine.EventSystems;
5. using UnityEngine.UI;
6.  
7. public class InertiaScrollRect : ScrollRect, IScrollHandler, IDragHandler
8. {
9.     // The speed at which the scrolling will slow down when inertia is applied
10.     float decelerationRate = 2;
11.  
12.     // The current velocity of the scrolling
13.     private float scrollVelocity;
14.  
15.     // A flag that indicates whether inertia is currently being applied
16.     private bool isInertiaActive = true;
17.  
18.     // Stop inertia when you click on the list
19.     public override void OnInitializePotentialDrag(PointerEventData eventData)
20.     {
21.         StopInertia();
22.     }
23.  
24.     public override void OnScroll(PointerEventData eventData)
25.     {
26.         // Calculate the amount of scrolling that should be applied based on the mouse wheel delta
27.  
28.         // I had to tone the regular scroll sensitivy of 1 way down for this to be not too fast
29.         // You can probaly mess around with the values here
30.         float scrollDelta = eventData.scrollDelta.y * (scrollSensitivity * 0.001f);
31.  
32.         // If inertia is currently being applied, we need to stop it before we can apply
33.         // the new scroll delta.
34.         if (isInertiaActive)
35.         {
36.             StopInertia();
37.         }
38.  
39.         float normalizedPosition = verticalNormalizedPosition;
40.  
41.         // Apply the scroll delta to the current normalized position
42.         normalizedPosition += scrollDelta;
43.  
44.         // Set the new normalized position of the scroll rect
45.          SetNormalizedPosition(normalizedPosition,1);
46.  
47.         // Start inertia scrolling with the current scroll velocity
48.         StartInertia(scrollDelta / Time.deltaTime);
49.     }
50.  
51.     // Update is called once per frame
52.     void Update()
53.     {
54.         if (isInertiaActive)
55.         {
56.  
57.             // Calculate the new scroll position based on the current scroll velocity
58.             float scrollDelta = scrollVelocity * Time.deltaTime;
59.  
60.             float normalizedPosition = verticalNormalizedPosition;
61.  
62.             // Apply the scroll delta to the current normalized position
63.             normalizedPosition += scrollDelta;
64.  
65.             if (normalizedPosition <= 0 || normalizedPosition >= 1)
66.             {
67.                 // The content has reached the top or bottom, so stop applying inertia
68.                 StopInertia();
69.             }
70.             else
71.             {
72.                 // The content has not reached the top or bottom, so set the new normalized position
73.                 // and continue applying inertia.
74.                 SetNormalizedPosition(normalizedPosition, 1);
75.  
76.                 // Reduce the scroll velocity according to the deceleration rate
77.                 scrollVelocity -= scrollVelocity * decelerationRate * Time.deltaTime;
78.  
79.                 // Check if the scroll velocity has reached 0
80.                 if (Mathf.Abs(scrollVelocity) <= 0)
81.                 {
82.                     // The scroll velocity has reached 0, so stop applying inertia
83.                     StopInertia();
84.                 }
85.             }
86.         }
87.     }
88.  
89.     // Start inertia scrolling with the specified scroll velocity
90.     private void StartInertia(float velocity)
91.     {
92.         scrollVelocity = velocity;
93.         isInertiaActive = true;
94.     }
95.  
96.     // Stop applying inertia to the scrolling
97.     private void StopInertia()
98.     {
99.         scrollVelocity = 0;
100.         isInertiaActive = false;
101.     }
102. }

 

Oh boy...!

 

Amazing. Thanks for sharing this script with us.