public void Render()
        {
            Framebuffer.Execute();
            Viewport.Execute();
            BlendState.Execute();
            FaceCullState.Execute();
            MaskState.Execute();
            DepthState.Execute();
            StencilState.Execute();
            Clear.Execute();
            camera.UpdateFrame();
            camera.UpdateViewport(Viewport.Viewport);
            foreach (var item in renderItems)
            {
#if false
                if (item.Model.Frame != frame)
                {
                    camera.UpdateModelFrame(frame);
                }
#endif
                //item.Batch.Mesh.ApplyAttributes(
            }
        }
        public void Render()
        {
            if (manipulator.Active == false)
            {
                return;
            }

            Model model = selectionManager.Models.First();

            manipulator.Parent = model;

            //  ManipulatorGroup is not updated by SceneManager.Update()
            sceneManager.UpdateOncePerFrame(ManipulatorGroup);

            renderer.CurrentGroup       = ManipulatorGroup;
            renderer.Requested.MeshMode = MeshMode.PolygonFill;

            //  Step 0: Lock depth, stencil and mask states
            Material.LockDepthState   = true;
            Material.LockStencilState = true;
            Material.LockMaskState    = true;
            Material.LockBlendState   = true;

            //  Hidden manipulator set stencil 1
            maskNoRGBADepth.Execute();
            depthGreater.Execute();
            stencilSetOne.Execute();
            BlendState.Default.Execute();
            renderer.RenderGroup();

            //  Visible manipulator set stencil 2
            maskNoRGBADepth.Execute();
            depthLEqual.Execute();
            stencilSetTwo.Execute();
            renderer.RenderGroup();

            //  Clear depth for manipulator
            maskDepthOnly.Execute();
            depthReplace.Execute();
            StencilState.Default.Execute();
            renderer.RenderGroup();

            //  Set depth for manipulator
            maskDepthOnly.Execute();
            depthLEqual.Execute();
            renderer.RenderGroup();

            //  Step 4: Render visible parts
            MaskState.Default.Execute();
            depthLEqual.Execute();
            stencilRequireTwo.Execute();
            BlendState.Default.Execute();
            renderer.RenderGroup();

            //  Step 5: Render with hidden depth and blend states
            maskNoDepth.Execute();
            depthLEqual.Execute();
            stencilRequireOne.Execute();
            blendHidden.Execute();
            renderer.RenderGroup();

            //  Unlock depth and blend states
            Material.LockDepthState   = false;
            Material.LockStencilState = false;
            Material.LockMaskState    = false;
            Material.LockBlendState   = false;

            Vector3 o      = model.Frame.LocalToWorld.Matrix.GetColumn3(3);
            Vector3 xStart = o; xStart.X -= 20.0f;
            Vector3 yStart = o;
            Vector3 zStart = o; zStart.Z -= 20.0f;
            Vector3 xEnd   = o; xEnd.X += 20.0f;
            Vector3 yEnd   = o; yEnd.Y = 0.0f;
            Vector3 zEnd   = o; zEnd.Z += 20.0f;

            lineRenderer.Begin();
            lineRenderer.Line(xStart, xEnd, new Vector4(1.0f, 0.0f, 0.0f, 1.0f));
            lineRenderer.Line(yStart, yEnd, new Vector4(0.0f, 1.0f, 0.0f, 1.0f));
            lineRenderer.Line(zStart, zEnd, new Vector4(0.0f, 0.0f, 1.0f, 1.0f));
            lineRenderer.End();
        }