Refactor HelixViewer extend format support

QuickLook.Plugin/QuickLook.Plugin.HelixViewer/HelixPanel.xaml.cs

@@ -15,13 +15,7 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-using Assimp;
-using HelixToolkit.Wpf;
-using System;
-using System.Linq;
 using System.Windows.Controls;
-using System.Windows.Media;
-using System.Windows.Media.Media3D;
 
 namespace QuickLook.Plugin.HelixViewer;
 
@@ -39,43 +33,4 @@ public partial class HelixPanel : UserControl
     {
         InitializeComponent();
     }
-
-    private void Load()
-    {
-        if (_path.EndsWith(".fbx", StringComparison.OrdinalIgnoreCase))
-        {
-            var context = new AssimpContext();
-            var scene = context.ImportFile(_path, PostProcessSteps.Triangulate);
-
-            foreach (var mesh in scene.Meshes)
-            {
-                var geometry = new MeshGeometry3D()
-                {
-                    Positions = [.. mesh.Vertices.Select(v => new Point3D(v.X, v.Y, v.Z))],
-                    TriangleIndices = [.. mesh.GetIndices()],
-                };
-                var model = new GeometryModel3D()
-                {
-                    Geometry = geometry,
-                    Material = Materials.Gray,
-                };
-
-                modelVisual.Content = model;
-            }
-        }
-        else
-        {
-            var modelImporter = new ModelImporter();
-            var model3DGroup = modelImporter.Load(_path);
-            var diffuseMaterial = new DiffuseMaterial(new SolidColorBrush(Color.FromRgb(0xA0, 0xA0, 0xA0)));
-
-            foreach (GeometryModel3D child in model3DGroup.Children.Cast<GeometryModel3D>())
-            {
-                child.Material = diffuseMaterial;
-                child.BackMaterial = diffuseMaterial;
-            }
-
-            modelVisual.Content = model3DGroup;
-        }
-    }
 }