public void OnMouseDrag()

OnMouseDrag is called every frame while the mouse is down. This event is sent to all scripts attached to the Collider. This function is not called on objects that belong to Ignore Raycast layer. This function is called on Colliders and 2D Colliders marked as trigger when the following properties are set to true: - For 3D physics: Physics.queriesHitTriggers - For 2D physics: Physics2D.queriesHitTriggers can be a coroutine. Note: New projects created with this version of Unity are pre-configured to use a version of the Input System that doesn't support this callback. To support this callback in your project, change the Active Input Handling setting in Player settings to either Both or Input Manager (Old). Using the old Input Manager alone is not recommended for new projects. For more information, refer to Input.

using UnityEngine;using System.Collections;public class ExampleClass : MonoBehaviour{    public Renderer rend;    void Start()    {        rend = GetComponent<Renderer>();    }    void OnMouseDrag()    {        rend.material.color -= Color.white * Time.deltaTime;    }}