[vtkusers] vtkVolumeTextureMapper3D memory consumption since 5.6

[Karthik Krishnan]

Simon:

Thanks. Please log a bug report at vtk.org/Bug, so we don't forget
about it. We should be querying the available VRAM (as is done in the
GPURaycast mapper) and the MAX_3D_TEXTURE_SIZE to compute the
decimated extents.

On a side note, you may want to experiment with seeing if you can
perform the "resample" faster using vtkImageResample. The 3D texture
mapper uses its own resampling, which is smart, but not multi-threaded
unlike vtkImageReslice. The gradient pre-computation and resampling
can be done a lot faster than it is now. You can log a feature request
/ (contribute a patch :) ) for the same.

--
karthik


On Fri, Oct 29, 2010 at 8:13 PM, Simon ESNEAULT <sesneault at gmail.com> wrote:
> Hi All,
> Since vtk 5.6 is out, we have some trouble using vtkVolumeTextureMapper3D.
> With VTK 5.4 rendering a volume of 512x512x366 consumes around 500 Mo and
> needs one or two seconds to load. The interactivity is good (20 fps)
> With VTK 5.6, rendering the same volume consumes 1700 Mo and needs more than
> 30 seconds to load. And the interactivity is unusable. (~1 fps)
> Test done on an intel i7 870 cpu, with an nvidia gtx 260, Ubuntu Linux 64
> bits (same result on windows 7).
> After some investigation, it appears that the pb, is the use of
> MAX_3D_TEXTURE_SIZE in the file vtkOpenGLVolumeTextureMapper3D.cxx instead
> of an harcoded max texture size (128*256*256) as it used to be in vtk 5.4.
> In the documentation it is said that all the volume will be resampled to a
> 128*256*256 volume, but it's no longer true in > 5.4.
> As a rough hack, if we changed the code around line 1970 of the
> file vtkOpenGLVolumeTextureMapper3D.cxx :
> int vtkOpenGLVolumeTextureMapper3D::IsTextureSizeSupported(int
> size[3], components)
> {
>   GLint maxSize;
>   glGetIntegerv(vtkgl::MAX_3D_TEXTURE_SIZE,&maxSize);
>   if(size[0]>maxSize || size[1]>maxSize || size[2]>maxSize)
>     {
>     return 0;
>     }
> ... into ...
> int vtkOpenGLVolumeTextureMapper3D::IsTextureSizeSupported(int
> size[3], components)
> {
>   GLint maxSize;
>   glGetIntegerv(vtkgl::MAX_3D_TEXTURE_SIZE,&maxSize);
>   maxSize = 256;
>   if(size[0]>maxSize || size[1]>maxSize || size[2]>maxSize)
>     {
>     return 0;
>     }
> ... we get back the good old behavior of this 3D volume mapper.
> Maybe this can be set as an option, something like
> mapper->Max3DTextureSizeOn(), to prevent that problem.
>
> Thanks for listening, and thanks a lot for VTK.
> -Simon
>
> --
> ------------------------------------------------------------------
> Simon Esneault - Therenva
> Centre d'Innovation Technologique
> Centre Cardio-Pneumologique
> CHU Pontchaillou
> Rennes, France
> Tel : +33 (0)6 64 61 30 94
> Mail : simon.esneault at therenva.com
> ------------------------------------------------------------------
>
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