My CompositionSurfaceVisual is not displayed

[martinrhan]

I added a custom control into the MainWindow

public partial class MainWindow : Window {
    public MainWindow() {
        InitializeComponent();
        this.Content = new DXControl();
    }
}

public class DXControl : Control{
    static IDXGIFactory7 DXGIFactory = DXGI.CreateDXGIFactory1<IDXGIFactory7>();
    static ID2D1Factory D2D1Factory = D2D1.D2D1CreateFactory<ID2D1Factory>();

    protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e) {
        int imageWidth = 1024;
        int imageHeight = 1024;

        ID3D11Device3 d3d11Device = D3D11.D3D11CreateDevice(DriverType.Hardware, DeviceCreationFlags.BgraSupport, Vortice.Direct3D.FeatureLevel.Level_11_1).QueryInterface<ID3D11Device3>();

        ID3D11Texture2D texture = d3d11Device.CreateTexture2D1(new() {
            Format = Format.R8G8B8A8_UNorm,
            Width = (uint)imageWidth,
            Height = (uint)imageHeight,
            ArraySize = 1,
            MipLevels = 1,
            SampleDescription = SampleDescription.Default,
            BindFlags = BindFlags.RenderTarget | BindFlags.ShaderResource,
            Usage = ResourceUsage.Default,
            CPUAccessFlags = CpuAccessFlags.None,
            MiscFlags = ResourceOptionFlags.SharedNTHandle | ResourceOptionFlags.SharedKeyedMutex,
            TextureLayout = TextureLayout.Undefined
        });

        IDXGIDevice dxgiDevice = d3d11Device.QueryInterface<IDXGIDevice>();

        ID2D1RenderTarget renderTarget = D2D1Factory.CreateDxgiSurfaceRenderTarget(
            texture.QueryInterface<IDXGISurface>(),
            new() {
                Type = RenderTargetType.Hardware,
                PixelFormat = new(Format.R8G8B8A8_UNorm, Vortice.DCommon.AlphaMode.Ignore),
                Usage = RenderTargetUsage.None,
                MinLevel = Vortice.Direct2D1.FeatureLevel.Default,
                DpiX = 0,
                DpiY = 0
            }
            );
        renderTarget.Clear(new(0xFF0000FF));

        IDXGIResource1 dxgiResource1 = texture.QueryInterface<IDXGIResource1>();
        IntPtr ptr = dxgiResource1.CreateSharedHandle(null, Vortice.DXGI.SharedResourceFlags.Read, null);
        PlatformHandle platformHandle = new(ptr, KnownPlatformGraphicsExternalImageHandleTypes.D3D11TextureNtHandle);

        Compositor compositor = ElementComposition.GetElementVisual(this)!.Compositor;
        var task = compositor.TryGetCompositionGpuInterop();
        ICompositionGpuInterop? gpuInterop = task.Result;
        if (gpuInterop is null) return;
        ICompositionImportedGpuImage importedImage = gpuInterop.ImportImage(
            platformHandle,
            new() {
                Format = PlatformGraphicsExternalImageFormat.R8G8B8A8UNorm,
                Width = imageWidth,
                Height = imageHeight,
                MemoryOffset = 0,
                MemorySize = (ulong)(imageWidth * imageHeight * sizeof(uint)),
                TopLeftOrigin = true
            }
            );

        CompositionSurfaceVisual visual = compositor.CreateSurfaceVisual();
        visual.Size = new(Bounds.Width, Bounds.Height);
        CompositionDrawingSurface compositionDrawingSurface = compositor.CreateDrawingSurface();
        visual.Surface = compositionDrawingSurface;
        compositionDrawingSurface.UpdateAsync(importedImage).ContinueWith(task => Debug.WriteLine("Update Completed"));

        ElementComposition.SetElementChildVisual(this, visual);
    }
}

I cannot find any problem within my code. The app can run and the window showed up without any exception. However, the window was blank and my ID3D11Texture2D which was cleared into red color wasn't present.

[kekekeks]

From a brief look you don't have a Flush call for your d3d device context and aren't using UpdateWithKeyedMutex to make sure that rendering is actually completed by the time Avalonia tries to take a snapshot

[kekekeks]

https://github.com/AvaloniaUI/Avalonia/tree/d3a2b086645087fef5fc1acb54ddbb41780de870/samples/GpuInterop/D3DDemo

[martinrhan]

Does the Avalonia debugger display composition visual in the visual tree?

[maxkatz6]

DevTools? No, it doesn't include composition info.

[martinrhan]

I solved the problem by putting the lines of codes into OnLoaded instead of OnAttachedToVisualTree