[vtkusers] Bugs in vtk 4.0

[Alexander Trum]

Hello,

We are using VTK 4.0 and we have found some bugs.
We have no CVS write access therefore i am writing this mail in the hope
somebody will fix it and check the changes in.

================================================================================
1. Bug in vtkIVWriter.cxx
================================================================================

change
--------------------------------------------------------------------------------
  if (colors)
    {
    fprintf(fp,"\tMaterial {\n");
    fprintf(fp,"\t\tdiffuseColor [\n");
    fprintf(fp, "\t\t\t");
    for (i=0; i<colors->GetNumberOfTuples(); i++)
      {
      unsigned char *rgba;
      rgba = colors->GetPointer(4*i);
      fprintf(fp, "%g %g %g, ", rgba[0]/255.0f,
              rgba[1]/255.0f, rgba[2]/255.0f);
      if (!((i+1)%2))
        {
        fprintf(fp, "\n\t\t\t");
        }
      }
    fprintf(fp, "\n\t\t]\n");
    fprintf(fp,"\t}\n");
    }
  colors->Delete();
--------------------------------------------------------------------------------
to
--------------------------------------------------------------------------------
  if (colors)
    {
    fprintf(fp,"\tMaterial {\n");
    fprintf(fp,"\t\tdiffuseColor [\n");
    fprintf(fp, "\t\t\t");
    for (i=0; i<colors->GetNumberOfTuples(); i++)
      {
      unsigned char *rgba;
      rgba = colors->GetPointer(4*i);
      fprintf(fp, "%g %g %g, ", rgba[0]/255.0f,
              rgba[1]/255.0f, rgba[2]/255.0f);
      if (!((i+1)%2))
        {
        fprintf(fp, "\n\t\t\t");
        }
      }
    fprintf(fp, "\n\t\t]\n");
    fprintf(fp,"\t}\n");
    colors->Delete();
    }
--------------------------------------------------------------------------------
because otherwise the program will crash if colors == NULL

================================================================================
2. Bug in vtkTriangleFilter.cxx
================================================================================

change the line 121 from
--------------------------------------------------------------------------------
if ( this->PassVerts )
--------------------------------------------------------------------------------
to
--------------------------------------------------------------------------------
if ( this->PassLines )
--------------------------------------------------------------------------------
because otherwise lines will only be passed if verts are passed!

================================================================================
3. Bug in vtkOBBTree.cxx
================================================================================

change the lines 1908 and 1909 from
--------------------------------------------------------------------------------
   delete OBBstackA;
   delete OBBstackB;
--------------------------------------------------------------------------------
to
--------------------------------------------------------------------------------
   delete[] OBBstackA;
   delete[] OBBstackB;
--------------------------------------------------------------------------------
because otherwise there will be memory leaks!

================================================================================
4. Bug in vtkDecimatePro.cxx
================================================================================

change
--------------------------------------------------------------------------------
static float ComputeEdgeError(float x[3], float x1[3], float x2[3])
{
  float projDist = vtkLine::DistanceToLine(x, x1, x2);
  float edgeLength = vtkMath::Distance2BetweenPoints(x1,x2);

  return (projDist < edgeLength ? projDist : edgeLength);
}
--------------------------------------------------------------------------------
to
--------------------------------------------------------------------------------
static float ComputeEdgeError(float x[3], float x1[3], float x2[3])
{
  float projDist = vtkLine::DistanceToLine(x, x1, x2);
  float edgeLength = vtkMath::Distance2BetweenPoints(x1,x2);

  float e = (projDist < edgeLength ? projDist : edgeLength);
  if (e < 0.0) e = 0.0;
  return e;
}
--------------------------------------------------------------------------------
because the implementation of vtkLine::DistanceToLine returns sometimes
negative values!!!
Perhaps it is much more better to fix this error in
vtkLine::DistanceToLine!
Effects: Only a few polygons will be kept after decimation of some large
polygonal models
if preserve topology is off and accumulate error is on!!!





Thanks a lot,
  Alexander

-- 
Alexander Trum
Dipl.-Math. (FH)
Senior Software Developer
Engineering IT Consulting
Teraport GmbH
Phone +49 89 651086 721
Fax +49 89 651086 701
Mobile +49 173 38 25 490
mailto:alexander.trum at teraport.de
http://www.teraport.de