ScriptableRenderPipeline/com.unity.shadergraph/Editor/Data/Graphs/SerializableCubemap.cs

using System;
using UnityEngine;

namespace UnityEditor.ShaderGraph
{
    [Serializable]
    public class SerializableCubemap
    {
        [SerializeField]
        string m_SerializedCubemap;

        [SerializeField]
        string m_Guid;

        [NonSerialized]
        Cubemap m_Cubemap;

        [Serializable]
        class CubemapHelper
        {
            public Cubemap cubemap;
        }

        public Cubemap cubemap
        {
            get
            {
                if (!string.IsNullOrEmpty(m_SerializedCubemap))
                {
                    var textureHelper = new CubemapHelper();
                    EditorJsonUtility.FromJsonOverwrite(m_SerializedCubemap, textureHelper);
                    m_SerializedCubemap = null;
                    m_Guid = AssetDatabase.AssetPathToGUID(AssetDatabase.GetAssetPath(textureHelper.cubemap));
                    m_Cubemap = textureHelper.cubemap;
                }
                else if (!string.IsNullOrEmpty(m_Guid) && m_Cubemap == null)
                {
                    m_Cubemap = AssetDatabase.LoadAssetAtPath<Cubemap>(AssetDatabase.GUIDToAssetPath(m_Guid));
                }

                return m_Cubemap;
            }
            set
            {
                m_SerializedCubemap = null;
                m_Guid = AssetDatabase.AssetPathToGUID(AssetDatabase.GetAssetPath(value));
                m_Cubemap = value;
            }
        }
    }
}