case WM_SIZE: // Window size has been changed
            if (g_D3DDev) // Resize D3D render target
            {
                // Release render target and depth-stencil view
                ID3D11RenderTargetView *nullRTV = NULL;
                g_D3DDevCtx->OMSetRenderTargets(1, &nullRTV, NULL);
                if (g_RenderTargetView)
                {
                    g_RenderTargetView->Release();
                    g_RenderTargetView = NULL;
                }
                if (g_DepthStencilView)
                {
                    g_DepthStencilView->Release();
                    g_DepthStencilView = NULL;
                }

                if (g_SwapChain)
                {
                    // Resize swap chain
                    g_SwapChainDesc.BufferDesc.Width = LOWORD(lParam);
                    g_SwapChainDesc.BufferDesc.Height = HIWORD(lParam);
                    g_SwapChain->ResizeBuffers(g_SwapChainDesc.BufferCount, g_SwapChainDesc.BufferDesc.Width,
                                               g_SwapChainDesc.BufferDesc.Height, g_SwapChainDesc.BufferDesc.Format,
                                               g_SwapChainDesc.Flags);

                    // Re-create a render target and depth-stencil view
                    ID3D11Texture2D *backBuffer = NULL, *dsBuffer = NULL;
                    g_SwapChain->GetBuffer(0, __uuidof(ID3D11Texture2D), (LPVOID*)&backBuffer);
                    g_D3DDev->CreateRenderTargetView(backBuffer, NULL, &g_RenderTargetView);
                    backBuffer->Release();
                    g_DepthStencilDesc.Width = g_SwapChainDesc.BufferDesc.Width;
                    g_DepthStencilDesc.Height = g_SwapChainDesc.BufferDesc.Height;
                    g_D3DDev->CreateTexture2D(&g_DepthStencilDesc, NULL, &dsBuffer);
                    g_D3DDev->CreateDepthStencilView(dsBuffer, NULL, &g_DepthStencilView);
                    dsBuffer->Release();
                    g_D3DDevCtx->OMSetRenderTargets(1, &g_RenderTargetView, g_DepthStencilView);

                    // Setup the viewport
                    D3D11_VIEWPORT vp;
                    vp.Width = (float)g_SwapChainDesc.BufferDesc.Width;
                    vp.Height = (float)g_SwapChainDesc.BufferDesc.Height;
                    vp.MinDepth = 0.0f;
                    vp.MaxDepth = 1.0f;
                    vp.TopLeftX = 0;
                    vp.TopLeftY = 0;
                    g_D3DDevCtx->RSSetViewports(1, &vp);
                }

                // TwWindowSize has been called by TwEventWin, so it is not necessary to call it again here.
            }
            return 0;