[vtkusers] Crash with FixedPointVolumeRayCastMapper

[Antoine Rosset]

Hi,

Yes, this crash occurs repeatedly when I rotate the object: suddenly  
it crashes at a specific angle. It seems the function try to access  
something outside the data memory zone.

Here are the parameters:

- float and unsigned char data (data is 512 x 512 x 51)
- 1 or 4 components
- with or without shading
- with or without linear opacity function

The crashes are not influenced by these parameters.

If I replace the vtkFixedPointVolumeRayCastMapper function by  
vtkVolumeRayCastMapper function, the crashes completely disappear.

BUT: if I change the reader->SetDataSpacing( 0.46875, 0.46875, 1.5)  
function to reader->SetDataSpacing( 1, 1, 1); the crashes DISAPPEAR.

The library is compiled under MacOS X 10.4, dual-G5, 2 GB of RAM.

BTW: This new function accelerate renderings by a factor from 4 to 8  
on dual-PowerPC systems compared to vtkVolumeRayCastMapper. And  
thanks for the new RGB support!

Sincerely,

Antoine Rosset

<> <> <> <> <> <> <> <> <> <> <> <> <> <> <> <> <><> <>
<> OSIRIX: Next Generation DICOM Viewer
<> http://homepage.mac.com/rossetantoine/osirix
<>
<> Antoine ROSSET, M.D. (RossetAntoine at bluewin.ch)
<> Blog : http://rossetantoine.blogspot.com/
<> Geneva University Hospital - Radiology Department
<> 20 Micheli-Du-Crest, CH-1205 Geneva
<> Switzerland, Europe
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On May 16, 2005, at 6:09 AM, Lisa Avila wrote:

> Hi Antoine,
>
> If you have some way of repeatedly causing the crash, I would love  
> to hear about it. Also, can you describe the type of data you are  
> rendering (data type and number of components, along with the  
> options you've selected such as MIP vs. composite, was shading on?  
> Is the gradient opacity function not a constant 1?), and your system?
>
> Thanks,
>
> Lisa