I'm wanting to export a 3D scene from a Viewport3D to a bitmap.
The obvious way to do this would be to use RenderTargetBitmap -- however when I this the quality of the exported bitmap is significantly lower than the on-screen image. Looking around on the internet, it seems that RenderTargetBitmap doesn't take advantage of hardware rendering. Which means that the rendering is done at Tier 0. Which means no mip-mapping etc, hence the reduced quality of the exported image.
Does anyone know how to export a bitmap of a Viewport3D at on-screen quality?
Clarification
Though the example given below doesn't show this, I need to eventually export the bitmap of the Viewport3D to a file. As I understand the only way to do this is to get the image into something that derives from BitmapSource. Cplotts below shows that increasing the quality of the export using RenderTargetBitmap improves the image, but as the rendering is still done in software, it is prohibitively slow.
Is there a way to export a rendered 3D scene to a file, using hardware rendering? Surely that should be possible?
Here's an example... on-screen quality:
RenderTargetBitmapQuality:
You can see the problem with this xaml:
<Window x:Class="RenderTargetBitmapProblem.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Height="400" Width="500">
<Grid>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Viewport3D Name="viewport3D">
<Viewport3D.Camera>
<PerspectiveCamera Position="0,0,3"/>
</Viewport3D.Camera>
<ModelVisual3D>
<ModelVisual3D.Content>
<AmbientLight Color="White"/>
</ModelVisual3D.Content>
</ModelVisual3D>
<ModelVisual3D>
<ModelVisual3D.Content>
<GeometryModel3D>
<GeometryModel3D.Geometry>
<MeshGeometry3D Positions="-1,-10,0 1,-10,0 -1,20,0 1,20,0"
TextureCoordinates="0,1 0,0 1,1 1,0"
TriangleIndices="0,1,2 1,3,2"/>
</GeometryModel3D.Geometry>
<GeometryModel3D.Material>
<DiffuseMaterial>
<DiffuseMaterial.Brush>
<ImageBrush ImageSource="http://www.wyrmcorp.com/galleries/illusions/Hermann%20Grid.png"
TileMode="Tile" Viewport="0,0,0.25,0.25"/>
</DiffuseMaterial.Brush>
</DiffuseMaterial>
</GeometryModel3D.Material>
</GeometryModel3D>
</ModelVisual3D.Content>
<ModelVisual3D.Transform>
<RotateTransform3D>
<RotateTransform3D.Rotation>
<AxisAngleRotation3D Axis="1,0,0" Angle="-82"/>
</RotateTransform3D.Rotation>
</RotateTransform3D>
</ModelVisual3D.Transform>
</ModelVisual3D>
</Viewport3D>
<Image Name="rtbImage" Visibility="Collapsed"/>
<Button Grid.Row="1" Click="Button_Click">RenderTargetBitmap!</Button>
</Grid>
</Window>
And this code:
private void Button_Click(object sender, RoutedEventArgs e)
{
RenderTargetBitmap bmp = new RenderTargetBitmap((int)viewport3D.ActualWidth,
(int)viewport3D.ActualHeight, 96, 96, PixelFormats.Default);
bmp.Render(viewport3D);
rtbImage.Source = bmp;
viewport3D.Visibility = Visibility.Collapsed;
rtbImage.Visibility = Visibility.Visible;
}