[Unity3DObjectDragHandler.cs] Handles drag and drop for a 3D object in Unity3D #unity #csharp #draganddrop

Unity3DObjectDragHandler.cs

using UnityEngine;

public class Unity3DObjectDragHandler : MonoBehaviour
{
    public Camera camera;

    public void Start()
    {
    }

    public void Update()
    {
        if (camera == null) return;

        if (Input.touchCount > 0)
        {
            var touch = Input.GetTouch(0);
            if (touch.phase == TouchPhase.Moved || touch.phase == TouchPhase.Stationary)
            {
                var touchPosition = touch.position;
                var rayFromCameraPassingThroughTouchPosition = camera.ScreenPointToRay(touchPosition);
                // Create a logical plane at this object's position and perpendicular to world Y
                var planeInCurrentObjectPosition = new Plane(Vector3.up, transform.position);
                if (planeInCurrentObjectPosition.Raycast(rayFromCameraPassingThroughTouchPosition, out var distance))
                {
                    var hitPos = rayFromCameraPassingThroughTouchPosition.GetPoint(distance);
                    transform.position = hitPos;
                }
            }
        }
    }
}