[vtkusers] Shadow support on volume rendering

[David E DeMarle]

Finally had a second to look into it.

There seem to be issues with short word type (and likely endian) in
the ospray volume renderer interface. Converting the array to float
results in a close match between ospray and gl volume rendered data.

Sorry for the hassle and delay Ian.

I'll file a bug report and we'll try and get it addressed.

Attached find a sample rendered with lighting and shadows enabled.

David E DeMarle
Kitware, Inc.
Principal Engineer
21 Corporate Drive
Clifton Park, NY 12065-8662
Phone: 518-881-4909


On Wed, Nov 8, 2017 at 4:57 AM, ianl <ilindsay at insigniamedical.co.uk> wrote:
> Hi David,
>
> Basically any DICOM CT set will do, but a good example is the Visible Human
> Female Ankle, available here:
> https://mri.radiology.uiowa.edu/VHDicom/VHFCT1mm/VHF-Ankle.tar.gz
>
> This renders fine (see image) with the GPU renderer. I get a totally black
> image when I add in the OSPRay render pass. I have verified this by writing
> a loop to check the value of all output pixels, all end up as zeros.
>
> <http://vtk.1045678.n5.nabble.com/file/t147622/render.png>
>
> I have had a play around with the TestOSPRayVolumeRenderer.cxx test. I
> removed the data surface filter so the test only renders the volumetric
> image, this seems to render fine with OSPRay, so it seems that my set-up is
> ok.
>
> As another test, I added a marching cubes filter to extract an iso surface
> to my pipeline, along with a vtkPolyDataMapper to render it. In this
> configuration, I see a surface rendered by OSPRay, so it seems that the
> issue is something specific to my pipeline and volumetric rendering. I'll
> keep digging.
>
>
>
> --
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