How to control stereo-frames separately with C#? (NVIDIA 3D shutter glasses)

Question

I’m trying to make a very simple application which would display different images on each eye. I have Asus VG236H monitor and NVIDIA 3D Vision kit, the stereo 3D shutter glasses. The I’m using C#, .NET Framework 2.0, DirectX 9 (Managed Direct X) and Visual Studio 2008. I have been searching high and low for examples and tutorials, have actually found a couple and based those I have created the program but for some reason I can’t get it working.

When looking for examples how to display different images for each eye, many people keep referring to the NVIDIA presentation at GDC 09 (the famous GDC09-3DVision-The_In_and_Out.pdf document) and the pages 37-40. My code is mainly constructed based on that example:

1. I'm loading two textures (Red.png and Blue.png) on surface (_imageLeft and _imageRight), in function LoadSurfaces()
2. Set3D() function puts those two images side-by-side to one bigger image which has the size of 2x Screen width and Screen height + 1 (_imageBuf).
3. Set3D() function continues by appending the stereo signature on the last row.
4. OnPaint()-function takes the back buffer (_backBuf) and copies the content of the combined image (_imageBuf) to it.

When I run the program, shutter glasses start working, but I only see the two images side-by-side on the screen. Could someone help out and tell me what am I doing wrong? I believe that solving this problem might also help others as there does not yet seem to be a simple example how to do this with C#.

Below are the tactical parts of my code. Complete project can be downloaded here: http://koti.mbnet.fi/jjantti2/NVStereoTest.rar

    public void InitializeDevice()
    {
        PresentParameters presentParams = new PresentParameters();

        presentParams.Windowed = false;
        presentParams.BackBufferFormat = Format.A8R8G8B8;
        presentParams.BackBufferWidth = _size.Width;
        presentParams.BackBufferHeight = _size.Height;
        presentParams.BackBufferCount = 1;
        presentParams.SwapEffect = SwapEffect.Discard;
        presentParams.PresentationInterval = PresentInterval.One;
        _device = new Device(0, DeviceType.Hardware, this, CreateFlags.SoftwareVertexProcessing, presentParams);
    }

    public void LoadSurfaces()
    {
        _imageBuf = _device.CreateOffscreenPlainSurface(_size.Width * 2, _size.Height + 1, Format.A8R8G8B8, Pool.Default);

        _imageLeft = Surface.FromBitmap(_device, (Bitmap)Bitmap.FromFile("Blue.png"), Pool.Default);
        _imageRight = Surface.FromBitmap(_device, (Bitmap)Bitmap.FromFile("Red.png"), Pool.Default);
    }

    private void Set3D()
    {
        Rectangle destRect = new Rectangle(0, 0, _size.Width, _size.Height);
        _device.StretchRectangle(_imageLeft, _size, _imageBuf, destRect, TextureFilter.None);
        destRect.X = _size.Width;
        _device.StretchRectangle(_imageRight, _size, _imageBuf, destRect, TextureFilter.None);

        GraphicsStream gStream = _imageBuf.LockRectangle(LockFlags.None);

        byte[] data = new byte[] {0x44, 0x33, 0x56, 0x4e,   //NVSTEREO_IMAGE_SIGNATURE         = 0x4433564e
                                  0x00, 0x00, 0x0F, 0x00,   //Screen width * 2 = 1920*2 = 3840 = 0x00000F00;
                                  0x00, 0x00, 0x04, 0x38,   //Screen height = 1080             = 0x00000438;
                                  0x00, 0x00, 0x00, 0x20,   //dwBPP = 32                       = 0x00000020;
                                  0x00, 0x00, 0x00, 0x02};  //dwFlags = SIH_SCALE_TO_FIT       = 0x00000002;

        gStream.Seek(_size.Width * 2 * _size.Height * 4, System.IO.SeekOrigin.Begin);   //last row
        gStream.Write(data, 0, data.Length);

        gStream.Close();

        _imageBuf.UnlockRectangle();
    }

    protected override void OnPaint(System.Windows.Forms.PaintEventArgs e)
    {
        _device.BeginScene();

        // Get the Backbuffer then Stretch the Surface on it.
        _backBuf = _device.GetBackBuffer(0, 0, BackBufferType.Mono);
        _device.StretchRectangle(_imageBuf, new Rectangle(0, 0, _size.Width * 2, _size.Height + 1), _backBuf, new Rectangle(0, 0, _size.Width, _size.Height), TextureFilter.None);
        _backBuf.ReleaseGraphics();

        _device.EndScene();

        _device.Present();

        this.Invalidate();
    }

Answer 1

A friend of mine found the problem. The bytes in the stereo signature were in reversed order. Here is the correct order:

byte[] data = new byte[] {0x4e, 0x56, 0x33, 0x44,   //NVSTEREO_IMAGE_SIGNATURE         = 0x4433564e;
0x00, 0x0F, 0x00, 0x00,   //Screen width * 2 = 1920*2 = 3840 = 0x00000F00;
0x38, 0x04, 0x00, 0x00,   //Screen height = 1080             = 0x00000438;
0x20, 0x00, 0x00, 0x00,   //dwBPP = 32                       = 0x00000020;
0x02, 0x00, 0x00, 0x00};  //dwFlags = SIH_SCALE_TO_FIT       = 0x00000002;

The code works perfectly after this change. This code might even serve as a good tutorial for someone else attempting the same thing. :)