SlimDX and WPF via D3DImage

Question

I've written some code using SlimDX and WPF where I would expect the end result to be a red screen.

Unfortunately all I get is a black screen.

This is on windows 7.

Can anyone see anything major I'm missing?

The reason I'm using a separate surface as the backbuffer for the D3DImage is that I am going to be needing multiple viewports. I thought that rendering to seperate surfaces instead of the devices initial backbuffer would be the best way to achieve that.

anyway, on with the code..

Disclaimer: Please ignore the bad code, this is written entirely as throw-away code just so I can figure out how to do achieve what I'm after.

Here's my window class:

namespace SlimDXWithWpf
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        SlimDXRenderer controller;

        public MainWindow()
        {
            InitializeComponent();
            controller = new SlimDXRenderer();
            controller.Initialize();

            D3DImage image = new D3DImage();

            image.Lock();
            controller.RenderToSurface();
            image.SetBackBuffer(D3DResourceType.IDirect3DSurface9, controller.SurfacePointer);
            image.AddDirtyRect(new Int32Rect(0, 0, image.PixelWidth, image.PixelHeight));            
            image.Unlock();

            Background = new ImageBrush(image);
        }
    }
}

And heres my "renderer" class

namespace SlimDXWithWpf
{
    public class SlimDXRenderer : IDisposable
    {
        Direct3DEx directX;
        DeviceEx device;
        Surface surface;
        Surface backBuffer;
        IntPtr surfacePointer;

        public IntPtr SurfacePointer
        {
            get
            {
                return surfacePointer;
            }
        }

        public void Initialize()
        {
            directX = new Direct3DEx();

            HwndSource hwnd = new HwndSource(0, 0, 0, 0, 0, 640, 480, "SlimDXControl", IntPtr.Zero);

            PresentParameters pp = new PresentParameters()
            {
                BackBufferCount = 1,
                BackBufferFormat = Format.A8R8G8B8,
                BackBufferWidth = 640,
                BackBufferHeight = 480,
                DeviceWindowHandle = hwnd.Handle,
                PresentationInterval = PresentInterval.Immediate,
                Windowed = true,
                SwapEffect = SwapEffect.Discard              
            };



            device = new DeviceEx(directX, 0, DeviceType.Hardware, hwnd.Handle, CreateFlags.HardwareVertexProcessing, pp);
            backBuffer = device.GetRenderTarget(0); 

            surface = Surface.CreateRenderTarget(device, 1024, 768, Format.A8R8G8B8, MultisampleType.None, 1, false);
            surfacePointer = surface.ComPointer;            
        }

        public void RenderToSurface()
        {
            device.SetRenderTarget(0, surface);
            device.Clear(ClearFlags.Target | ClearFlags.ZBuffer, new Color4(Color.Red), 0f, 0);
            device.BeginScene();            
            device.EndScene();                        
        }

        public void Dispose()
        {
            surface.Dispose();
            device.Dispose();
            directX.Dispose();
        }
    }
}

-- Edit: For a second I had thought I'd solved it, but it seems it will only work when my second render target (the one I'm trying to clear red) is 640x480. Any thoughts?

Answer 1

Did you base some of this code on the SlimDX WPF sample? It looks like you might have, which is why your Clear() call is using 0.0f for the Z clear value... which is a bug in our sample. It should be 1.0f.

Beyond that, the only potential issue I see is that your surface render target is a different size than your back buffer, but that should not actually cause problems. Have you tried rendering to the device's backbuffer (Device.GetBackBuffer()) instead of a new surface to see what impact that has?