Quick code to get a WPF Visual to DirectX Texture (performance wise)

Question

Well, the problem is simple, I have something rendered on a WPF Visual. I want to get it to on a DirectX Texture. At present, I using the following code to get the job done.

var bmp = new System.Windows.Media.Imaging.RenderTargetBitmap(bound.Width, bound.Height, 96, 96, System.Windows.Media.PixelFormats.Pbgra32);
bmp.Render(drawingVisual);
var encoder = new System.Windows.Media.Imaging.PngBitmapEncoder();
encoder.Frames.Add(System.Windows.Media.Imaging.BitmapFrame.Create(bmp));
Texture texture = new Texture(dxDevice, bound.Width, bound.Height, 1, Usage.RenderTarget, Format.A8R8G8B8, Pool.Default);
using (MemoryStream ms = new MemoryStream())
{
    encoder.Save(ms);
    ms.Seek(0, SeekOrigin.Begin);
    Surface privateSurface = texture.GetSurfaceLevel(0);
    SurfaceLoader.FromStream(privateSurface, ms, Filter.None, Color.MediumAquamarine.ToArgb());
    ms.Close();
}
return texture; // our prepared texture

But it's somewhat slow, in an obvious manner. Can you guys suggest something which could possibly make it quicker?

[EDIT] I tried to load the data using CopyPixels(), but it throws D3DXERR_INVALIDDATA exception.

RenderTargetBitmap bmp = GetBitmap();
// copy into a byte array
int stride = bmp.PixelWidth * 4; 
byte[] data = new byte[bmp.PixelHeight * stride]; 
bmp.CopyPixels(data, stride, 0); 

// create texture
using (MemoryStream ms = new MemoryStream(data))
{
    ms.Seek(0, SeekOrigin.Begin);

    if (dxDevice != null)
    {
        // next line throws D3DXERR_INVALIDDATA exception
        texture = TextureLoader.FromStream(dxDevice, ms);
    }
}

[EDIT] Ok, so here's how I managed to do it.

RenderTargetBitmap bmp = GetBitmap();
// copy into a byte array
int stride = bmp.PixelWidth * 4; 
byte[] data = new byte[bmp.PixelHeight * stride]; 
bmp.CopyPixels(data, stride, 0); 

// create texture
Texture texture = new Texture(dxDevice, bound.Width, bound.Height, 1, Usage.SoftwareProcessing, Format.A8R8G8B8, Pool.Managed);
Surface privateSurface = texture.GetSurfaceLevel(0);
var graphicsStream = privateSurface.LockRectangle(LockFlags.None);
graphicsStream.Write(data);
privateSurface.UnlockRectangle();

Alex Shtoff · Accepted Answer · 2011-04-24T10:27:23.170

2

Yes. You can still use RenderTargetBitmap. But instead of encoding it to PNG and reading in Direct3D, you can call CopyPixels on your RenderTargetBitmap and then write the pixels directly to your texture. Should be much faster!

// render the visual, just like you did
var bmp = new RenderTargetBitmap(width, height, 96, 96, PixelFormats.Default, null);
bmp.Render(visual);

// get the pixels
var pixels = new int[width * height];
bmp.CopyPixels(pixels, 4 * width, 0); // each line consists of 4*width bytes.

And now, depending on the exact API you use (SlimDX? Something else?) you need to lock your texture, and write the data in the pixels array to the texture.

edited Apr 24 '11 at 10:27

answered Apr 23 '11 at 22:08

Alex Shtoff

2,520
1
25
53

Updated my question. I did try to do what you suggested but it throws D3DXERR_INVALIDDATA exception. Anything else you wanna suggest? – Trainee4Life Apr 24 '11 at 19:02
1

FromStream doesn't do what you think. It tries to load a known file format, not raw texture data. If you are using SlimDX, the correct thing to do is texture.GetSurfaceLevel(0), lock the surface and write the pixels directly to the surface. – Alex Shtoff Apr 25 '11 at 12:36
Well, I thought so. Thanks for pointing me to the 'right' API. I'll give it a try and let you know. – Trainee4Life Apr 25 '11 at 15:32
I could use LockRectangle() only on texture from Pool.Managed with Usage.SoftwareProcessing. Any idea why? BTW just updated my question with what I did based on your suggestion. Thanks a lot Alex! – Trainee4Life Apr 26 '11 at 19:51

Quick code to get a WPF Visual to DirectX Texture (performance wise)

1 Answers1