[Paraview] Re: [vtk-developers] Integrating new volume renderer into VTK/Paraview

[Lisa Avila]

Hi Steve,

Can you send me the code? (either point me to an ftp location or I can give 
you instructions for uploading files here) We'll look it over here, see 
what we may need to do on the OpenGL header issues (are you using the 
vtkOpenGLExtensionManager to manage the use of your extensions and get the 
function pointers?) It shouldn't be too hard to get this into VTK.

For ParaView, we are currently using a 2 level LOD method with Projected 
Tetras being the "fast" one always, and either no second level, or ZSweep 
or the ray caster for final rendering. This would probably be different in 
that we would replace PT whenever possible with this new method (as long as 
the required extensions were available). We can worry about this once the 
class is integrated into VTK.

Thanks,

Lisa



At 01:20 PM 12/8/2005, Steven Callahan wrote:
>We are working on integrating the Hardware-Assisted Visibility Sorting 
>(HAVS) volume renderer into VTK and ParaView.  We have a prototype version 
>that performs at about twice the speed of  Projected Tetrahedra with about 
>the same image quality as ZSweep, incorporated into ParaView.  (ZSweep has 
>much better image quality than PT.)
>
>We would like to know what steps we need to take to get this added to VTK 
>and ParaView.
>
>Our implementation is a new volume mapper 
>vtkHAVSUnstructuredGridVolumeMapper that can be used in place of any of 
>the other unstructured grid volume mappers.  The actual code consists of 
>the mapper class along with several shader files which are written in ARB 
>assembly and work with ATI and NVidia video cards.  The code also supports 
>a new high quality, dynamic Level-of-Detail approach by passing in a 
>desired frame rate...
>
>For integration with VTK, we see the following issue: Our code requires 
>the most recent OpenGL extension header files.  VTK currently uses headers 
>that are slightly out of date.  The newest headers are always available at 
>the SGI website (http://oss.sgi.com/projects/ogl-sample/registry/).
>
>We have integrated our code into ParaView.   For screenshots comparing PT 
>with HAVS, see http://www.sci.utah.edu/~stevec/images.
>
>For complete integration with ParaView, we see the following issues:
>1.  We do not understand ParaView's LOD selection.  Thus, we have not 
>incorporated our LOD technique inside ParaView.  We would appreciate 
>getting help from someone that knows the details of how this works.
>2.  Although our code works on both ATI and NVidia, ParaView does not seem 
>to use hardware-acceleration on machines with ATI cards.  Even with the 
>precompiled Windows binaries from the web, the PT algorithm is extremely 
>slow, indicating that hardware rendering is not being used.
>Is this an intrinsic limitation of ParaView?
>
>Any help or advice on getting this code into VTK and ParaView would be 
>helpful.  Thanks
>
>Steve Callahan and Claudio Silva
>
>PS. We also have an efficient software volume renderer based on the same 
>algorithm that we would like to incorporate in the near future.
>
>
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