Drag and drop scripts not working

Scripting
1

Hey everyone,
I’m trying to make my first game, and the first puzzle is a very simple drag and drop one. However, every tutorial I’ve watched on how to make a drag and drop script doesn’t seem to work. It doesn’t even pop up with an error message or anything, I don’t think the puzzle piece is being recognized at all. I got chatGPT to write me a script with some debug messages as a last resort, but that script isn’t working either and when I hover over the puzzle piece, the mouse isn’t even detected.
Here are the links to the youtube videos I watched:

  1. https://www.youtube.com/watch?v=o_qEXZhQR-M
  2. https://www.youtube.com/watch?v=SgWMQCE1_Oo

Here’s the script chatGPT gave me:

using UnityEngine;

public class DragAndDrop2D : MonoBehaviour
{
    private Vector3 offset;
    private float zCoord;

    void OnMouseDown()
    {
        Debug.Log("Mouse DOWN on: " + gameObject.name);

        // Store object's Z coordinate
        zCoord = Camera.main.WorldToScreenPoint(transform.position).z;

        // Calculate offset between object and mouse world pos
        offset = transform.position - GetMouseWorldPos();

        Debug.Log("Offset set to: " + offset);
    }

    void OnMouseDrag()
    {
        Debug.Log("Dragging: " + gameObject.name);

        transform.position = GetMouseWorldPos() + offset;

        Debug.Log("New position: " + transform.position);
    }

    void OnMouseUp()
    {
        Debug.Log("Mouse UP on: " + gameObject.name);
    }

    private Vector3 GetMouseWorldPos()
    {
        Vector3 mousePoint = Input.mousePosition;

        // Maintain the object's Z so it doesn't jump
        mousePoint.z = zCoord;

        Vector3 world = Camera.main.ScreenToWorldPoint(mousePoint);

        Debug.Log("Mouse world position: " + world);

        return world;
    }
}

Also, I opened a new project and quickly threw together a test to see if it was a problem with that specific project, however it still didn’t work.

I’m unsure if theres some hidden setting I need to configure or something, so any guidance would be greatly appreciated. If further info is needed, let me know. Thanks.

2

The reason none of these solutions work is that they rely on OnMouseDown() and similar event methods, which function only when the legacy Input Manager is enabled.

You have two options:

  1. Change the Active Input Handling setting in Player Settings to “Both” or “Input Manager (Old).” This is not recommended, as the legacy Input Manager is being phased out and the newer Input System is the preferred option for current and future projects.
  2. Find tutorials that use the new Input System. This is the recommended approach because you will learn to use the system that will be the default for Unity input from now on.