[vtkusers] error in vtkFixedPointVolumeRayCastHelper MoveToNextSample macros ?

[xabi riobe]

Hi,

I am working with FixedPointVolumeRayCast and it seems to me that there is a
mistake in the helper macros when incrementing the ray position.

for example:
#define
VTKKWRCHelper_MoveToNextSampleNN()                                      \
  if ( k < numSteps-1
)                                                         \

{
\
    mapper->FixedPointIncrement( pos, dir
);                                    \
    mapper->ShiftVectorDown( pos, spos
);                                       \
    dptr = data +  spos[0]*inc[0] + spos[1]*inc[1] +
spos[2]*inc[2];            \
    }


is called in FixedPointCompositeHelperGenerateImageOneSimpleNN

for( k=0; k<numSteps; ++k)
{
  if( k )
  {
     VTKKWRCHelper_MoveToNextSampleNN();
  }

   // the rest of the loop computes the color value
  ...
}


so if we have 3 steps in the ray, when k == 0 we compute the first sample
value,
then k == 1 we move to second sample and compute the value,
and then k == 2 and instead of moving to third sample we stay at the same
position and recompute the previous value.

I think the condition in the macro should be:
if ( k < numSteps )

for all the VTKKWRCHelper_MoveToNextSample*** macros



Is this true or am i missing something?


XR.
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