I'm trying to use direct2d to render images off-screen using WindowsAPICodePack. This is easily achieved using WicBitmapRenderTarget but sadly it's not hardware accelerated.

So I'm trying this route:

1. Create direct3d device
2. Create texture2d
3. Use texture surface to create render target using CreateDxgiSurfaceRenderTarget
4. Draw some shapes

While this renders the image it appears GPU isn't being used at all while CPU is used heavily.

Am I doing something wrong? Is there a way to check whether hardware or software rendering is used?

Code sample:

var device =  D3DDevice1.CreateDevice1(
                null,
                DriverType.Hardware,
                null,
                CreateDeviceOptions.SupportBgra
                ,FeatureLevel.Ten
                );

 var txd = new Texture2DDescription();
            txd.Width = 256;
            txd.Height = 256;
            txd.MipLevels = 1;
            txd.ArraySize = 1;
            txd.Format = Format.B8G8R8A8UNorm; //DXGI_FORMAT_R32G32B32A32_FLOAT;
            txd.SampleDescription = new SampleDescription(1,0);
            txd.Usage = Usage.Default;
            txd.BindingOptions = BindingOptions.RenderTarget | BindingOptions.ShaderResource;
            txd.MiscellaneousResourceOptions = MiscellaneousResourceOptions.None;
            txd.CpuAccessOptions = CpuAccessOptions.None;

            var tx = device.CreateTexture2D(txd);

            var srfc = tx.GraphicsSurface;

            var d2dFactory = D2DFactory.CreateFactory();

            var renderTargetProperties = new RenderTargetProperties
            {
                PixelFormat = new PixelFormat(Format.Unknown, AlphaMode.Premultiplied),
                DpiX = 96,
                DpiY = 96,
                RenderTargetType = RenderTargetType.Default,
            };

            using(var renderTarget = d2dFactory.CreateGraphicsSurfaceRenderTarget(srfc, renderTargetProperties))
            {
                renderTarget.BeginDraw();
                var clearColor = new ColorF(1f,1f,1f,1f);
                renderTarget.Clear(clearColor);
                using (var strokeBrush = renderTarget.CreateSolidColorBrush(new ColorF(0.2f,0.2f,0.2f,1f)))
                {
                    for (var i = 0; i < 100000; i++)
                    {
                        renderTarget.DrawEllipse(new Ellipse(new Point2F(i, i), 10, 10), strokeBrush, 2);
                    }
                }

                var hr = renderTarget.EndDraw();
            }