Reference TSkinVertexBuffer

  TSkinVertexBuffer = class(TDrawingBuffer<TSkinVertex>)
  protected
    function CountAttributes: Integer; override;
    procedure BindAttributes; override;
  public
    { Add a vertex, returning the buffer so calls can be chained }
    function Add(const V, N: TVec3; const Tex: TVec2; const Bones, Weights: TVec4): TSkinVertexBuffer; overload;
  end;