UnityEditor.MaterialEditor.GetPreviewType C# (CSharp) Method

        private static PreviewType GetPreviewType(Material mat)
        {
            if (mat != null)
            {
                switch (mat.GetTag("PreviewType", false, string.Empty).ToLower())
                {
                    case "plane":
                        return PreviewType.Plane;

                    case "skybox":
                        return PreviewType.Skybox;
                }
                if ((mat.shader != null) && mat.shader.name.Contains("Skybox"))
                {
                    return PreviewType.Skybox;
                }
            }
            return PreviewType.Mesh;
        }