Input.mouseScrollDelta

Description

The current mouse scroll delta. (Read Only)

Note: This API is part of the legacy Input class, and not recommended for new projects. The documentation is provided here to support legacy projects that use the old Input Manager and Input class. For new projects you should use the newer and Input System Package. (read more).

Input.mouseScrollDelta is stored in a Vector2.y property. (The Vector2.x value is ignored.) Input.mouseScrollDelta can be positive (up) or negative (down). The value is zero when the mouse scroll is not rotated. Note that a mouse with a center scroll wheel is typical on a PC. Modern macOS uses double finger movement up and down on the trackpad to emulate center scrolling. The value returned by mouseScrollDelta will need to be adjusted according to the scroll rate. In the example below a scale of 0.1f is used.

Note that mouseScrollDelta is read-only.

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

// Input.mouseScrollDelta example
//
// Create a sphere moved by a mouse scrollwheel or two-finger
// slide on a Mac trackpad.

public class ExampleClass : MonoBehaviour
{
    private Transform sphere;
    private float scale;

    void Awake()
    {
        GameObject go = GameObject.CreatePrimitive(PrimitiveType.Sphere);
        sphere = go.transform;

        // create a yellow quad
        go = GameObject.CreatePrimitive(PrimitiveType.Quad);
        go.transform.Rotate(new Vector3(90.0f, 0.0f, 0.0f));
        go.transform.localScale = new Vector3(4.0f, 4.0f, 4.0f);
        go.GetComponent<Renderer>().material.color = new Color(0.75f, 0.75f, 0.0f, 0.5f);

        // change the camera color and position
        Camera.main.clearFlags = CameraClearFlags.SolidColor;
        Camera.main.transform.position = new Vector3(2, 1, 5);
        Camera.main.transform.Rotate(0, -160, 0);

        scale = 0.1f;
    }

    void OnGUI()
    {
        Vector3 pos = sphere.position;
        pos.y += Input.mouseScrollDelta.y * scale;
        sphere.position = pos;
    }
}