message: Make sure we access the diffuse texture channel
diff: @@ -630,10 +630,10 @@ struct build_scene_visitor : sg::node_visitor
  {
  unsigned prev = current_geom_id_;
  - if (sp.flags() == 0 && sp.material() && sp.textures().size() > 0)
  + if (sp.flags() == 0 && sp.material() && sp.textures().find("diffuse") != sp.textures().end())
  {
  std::shared_ptr<sg::material> material = sp.material();
  - std::shared_ptr<sg::texture> texture = sp.textures()[0];
  + std::shared_ptr<sg::texture> texture = sp.textures()["diffuse"];
  auto surf = std::make_pair(material, texture);
  