arfoundation-samples/Assets/Scripts/UX/FadePlaneOnBoundaryChange.cs

using UnityEngine;
using UnityEngine.XR.ARFoundation;

namespace UnityEngine.XR.ARFoundation.Samples
{
    [RequireComponent(typeof(ARPlane))]
    [RequireComponent(typeof(Animator))]
    public class FadePlaneOnBoundaryChange : MonoBehaviour
    {
        const string k_FadeOffAnim = "FadeOff";
        const string k_FadeOnAnim = "FadeOn";
        const float k_TimeOut = 2.0f;

        Animator m_Animator;
        ARPlane m_Plane;

        float m_ShowTime = 0;
        bool m_UpdatingPlane = false;

        void OnEnable()
        {
            m_Plane = GetComponent<ARPlane>();
            m_Animator = GetComponent<Animator>();

            m_Plane.boundaryChanged += PlaneOnBoundaryChanged;
        }

        void OnDisable()
        {
            m_Plane.boundaryChanged -= PlaneOnBoundaryChanged;
        }

        void Update()
        {
            if (m_UpdatingPlane)
            {
                m_ShowTime -= Time.deltaTime;

                if (m_ShowTime <= 0)
                {
                    m_UpdatingPlane = false;
                    m_Animator.SetBool(k_FadeOffAnim, true);
                    m_Animator.SetBool(k_FadeOnAnim, false);
                }
            }
        }

        void PlaneOnBoundaryChanged(ARPlaneBoundaryChangedEventArgs obj)
        {
            m_Animator.SetBool(k_FadeOffAnim, false);
            m_Animator.SetBool(k_FadeOnAnim, true);
            m_UpdatingPlane = true;
            m_ShowTime = k_TimeOut;
        }
    }
}