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Walkthrough: Hosting Direct3D9 Content in WPF

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This walkthrough shows how to host Direct3D9 content in a Windows Presentation Foundation (WPF) application.

In this walkthrough, you perform the following tasks:

  • Create a WPF project to host the Direct3D9 content.

  • Import the Direct3D9 content.

  • Display the Direct3D9 content by using the D3DImage class.

When you are finished, you will know how to host Direct3D9 content in a WPF application.

Prerequisites

You need the following components to complete this walkthrough:

Creating the WPF Project

The first step is to create the project for the WPF application.

To create the WPF project

Create a new WPF Application project in Visual C# named D3DHost. For more information, see Walkthrough: My first WPF desktop application.

MainWindow.xaml opens in the WPF Designer.

Importing the Direct3D9 Content

You import the Direct3D9 content from an unmanaged DLL by using the DllImport attribute.

To import Direct3D9 content

  1. Open MainWindow.xaml.cs in the Code Editor.

  2. Replace the automatically generated code with the following code.

    using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Interop;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Windows.Threading;
using System.Runtime.InteropServices;
using System.Security.Permissions;

namespace D3DHost
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            // Set up the initial state for the D3DImage.
            HRESULT.Check(SetSize(512, 512));
            HRESULT.Check(SetAlpha(false));
            HRESULT.Check(SetNumDesiredSamples(4));

            //
            // Optional: Subscribing to the IsFrontBufferAvailableChanged event.
            //
            // If you don't render every frame (e.g. you only render in
            // reaction to a button click), you should subscribe to the
            // IsFrontBufferAvailableChanged event to be notified when rendered content
            // is no longer being displayed. This event also notifies you when
            // the D3DImage is capable of being displayed again.

            // For example, in the button click case, if you don't render again when
            // the IsFrontBufferAvailable property is set to true, your
            // D3DImage won't display anything until the next button click.
            //
            // Because this application renders every frame, there is no need to
            // handle the IsFrontBufferAvailableChanged event.
            //
            CompositionTarget.Rendering += new EventHandler(CompositionTarget_Rendering);

            //
            // Optional: Multi-adapter optimization
            //
            // The surface is created initially on a particular adapter.
            // If the WPF window is dragged to another adapter, WPF
            // ensures that the D3DImage still shows up on the new
            // adapter.
            //
            // This process is slow on Windows XP.
            //
            // Performance is better on Vista with a 9Ex device. It's only
            // slow when the D3DImage crosses a video-card boundary.
            //
            // To work around this issue, you can move your surface when
            // the D3DImage is displayed on another adapter. To
            // determine when that is the case, transform a point on the
            // D3DImage into screen space and find out which adapter
            // contains that screen space point.
            //
            // When your D3DImage straddles two adapters, nothing
            // can be done, because one will be updating slowly.
            //
            _adapterTimer = new DispatcherTimer();
            _adapterTimer.Tick += new EventHandler(AdapterTimer_Tick);
            _adapterTimer.Interval = new TimeSpan(0, 0, 0, 0, 500);
            _adapterTimer.Start();

            //
            // Optional: Surface resizing
            //
            // The D3DImage is scaled when WPF renders it at a size
            // different from the natural size of the surface. If the
            // D3DImage is scaled up significantly, image quality
            // degrades.
            //
            // To avoid this, you can either create a very large
            // texture initially, or you can create new surfaces as
            // the size changes. Below is a very simple example of
            // how to do the latter.
            //
            // By creating a timer at Render priority, you are guaranteed
            // that new surfaces are created while the element
            // is still being arranged. A 200 ms interval gives
            // a good balance between image quality and performance.
            // You must be careful not to create new surfaces too
            // frequently. Frequently allocating a new surface may
            // fragment or exhaust video memory. This issue is more
            // significant on XDDM than it is on WDDM, because WDDM
            // can page out video memory.
            //
            // Another approach is deriving from the Image class,
            // participating in layout by overriding the ArrangeOverride method, and
            // updating size in the overriden method. Performance will degrade
            // if you resize too frequently.
            //
            // Blurry D3DImages can still occur due to subpixel
            // alignments.
            //
            _sizeTimer = new DispatcherTimer(DispatcherPriority.Render);
            _sizeTimer.Tick += new EventHandler(SizeTimer_Tick);
            _sizeTimer.Interval = new TimeSpan(0, 0, 0, 0, 200);
            _sizeTimer.Start();
        }

        ~MainWindow()
        {
            Destroy();
        }

        void AdapterTimer_Tick(object sender, EventArgs e)
        {
            POINT p = new POINT(imgelt.PointToScreen(new Point(0, 0)));

            HRESULT.Check(SetAdapter(p));
        }

        void SizeTimer_Tick(object sender, EventArgs e)
        {
            // The following code does not account for RenderTransforms.
            // To handle that case, you must transform up to the root and
            // check the size there.

            // Given that the D3DImage is at 96.0 DPI, its Width and Height
            // properties will always be integers. ActualWidth/Height
            // may not be integers, so they are cast to integers.
            uint actualWidth = (uint)imgelt.ActualWidth;
            uint actualHeight = (uint)imgelt.ActualHeight;
            if ((actualWidth > 0 && actualHeight > 0) &&
                (actualWidth != (uint)d3dimg.Width || actualHeight != (uint)d3dimg.Height))
            {
                HRESULT.Check(SetSize(actualWidth, actualHeight));
            }
        }

        void CompositionTarget_Rendering(object sender, EventArgs e)
        {
            RenderingEventArgs args = (RenderingEventArgs)e;

            // It's possible for Rendering to call back twice in the same frame
            // so only render when we haven't already rendered in this frame.
            if (d3dimg.IsFrontBufferAvailable && _lastRender != args.RenderingTime)
            {
                IntPtr pSurface = IntPtr.Zero;
                HRESULT.Check(GetBackBufferNoRef(out pSurface));
                if (pSurface != IntPtr.Zero)
                {
                    d3dimg.Lock();
                    // Repeatedly calling SetBackBuffer with the same IntPtr is
                    // a no-op. There is no performance penalty.
                    d3dimg.SetBackBuffer(D3DResourceType.IDirect3DSurface9, pSurface);
                    HRESULT.Check(Render());
                    d3dimg.AddDirtyRect(new Int32Rect(0, 0, d3dimg.PixelWidth, d3dimg.PixelHeight));
                    d3dimg.Unlock();

                    _lastRender = args.RenderingTime;
                }
            }
        }

        DispatcherTimer _sizeTimer;
        DispatcherTimer _adapterTimer;
        TimeSpan _lastRender;

        // Import the methods exported by the unmanaged Direct3D content.

        [DllImport("D3DCode.dll")]
        static extern int GetBackBufferNoRef(out IntPtr pSurface);

        [DllImport("D3DCode.dll")]
        static extern int SetSize(uint width, uint height);

        [DllImport("D3DCode.dll")]
        static extern int SetAlpha(bool useAlpha);

        [DllImport("D3DCode.dll")]
        static extern int SetNumDesiredSamples(uint numSamples);

        [StructLayout(LayoutKind.Sequential)]
        struct POINT
        {
            public POINT(Point p)
            {
                x = (int)p.X;
                y = (int)p.Y;
            }

            public int x;
            public int y;
        }

        [DllImport("D3DCode.dll")]
        static extern int SetAdapter(POINT screenSpacePoint);

        [DllImport("D3DCode.dll")]
        static extern int Render();

        [DllImport("D3DCode.dll")]
        static extern void Destroy();
    }

    public static class HRESULT
    {
        public static void Check(int hr)
        {
            Marshal.ThrowExceptionForHR(hr);
        }
    }
}

Hosting the Direct3D9 Content

Finally, use the D3DImage class to host the Direct3D9 content.

To host the Direct3D9 content

  1. In MainWindow.xaml, replace the automatically generated XAML with the following XAML.

        <Window x:Class="D3DHost.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:i="clr-namespace:System.Windows.Interop;assembly=PresentationCore"
    Title="MainWindow" Height="300" Width="300" Background="PaleGoldenrod">
    <Grid>
        <Image x:Name="imgelt">
            <Image.Source>
                <i:D3DImage x:Name="d3dimg" />
            </Image.Source>
        </Image>
    </Grid>
</Window>

  2. Build the project.

  3. Copy the DLL that contains the Direct3D9 content to the bin/Debug folder.

  4. Press F5 to run the project.

    The Direct3D9 content appears within the WPF application.

See also