/*
   ____    _ __           ____               __    ____
  / __/___(_) /  ___ ____/ __ \__ _____ ___ / /_  /  _/__  ____
 _\ \/ __/ / _ \/ -_) __/ /_/ / // / -_|_-</ __/ _/ // _ \/ __/
/___/\__/_/_.__/\__/_/  \___\_\_,_/\__/___/\__/ /___/_//_/\__(_)

Copyright 2012 SciberQuest Inc.

*/
/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkSQTubeFilter.cxx

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
#include "vtkSQTubeFilter.h"

#include "vtkCellArray.h"
#include "vtkCellData.h"
#include "vtkFloatArray.h"
#include "vtkMath.h"
#include "vtkInformation.h"
#include "vtkInformationVector.h"
#include "vtkObjectFactory.h"
#include "vtkPointData.h"
#include "vtkPointSet.h"
#include "vtkPolyData.h"
#include "vtkUnstructuredGrid.h"
#include "vtkPolyLine.h"

vtkStandardNewMacro(vtkSQTubeFilter);

// Construct object with radius 0.5, radius variation turned off, the number
// of sides set to 3, and radius factor of 10.
//----------------------------------------------------------------------------
vtkSQTubeFilter::vtkSQTubeFilter()
{
  this->Radius = 0.5;
  this->VaryRadius = VTK_VARY_RADIUS_OFF;
  this->NumberOfSides = 3;
  this->RadiusFactor = 10;

  this->DefaultNormal[0] = this->DefaultNormal[1] = 0.0;
  this->DefaultNormal[2] = 1.0;

  this->UseDefaultNormal = 0;
  this->SidesShareVertices = 1;
  this->Capping = 0;
  this->OnRatio = 1;
  this->Offset = 0;

  this->GenerateTCoords = VTK_TCOORDS_OFF;
  this->TextureLength = 1.0;

  // by default process active point scalars
  this->SetInputArrayToProcess(0,0,0,vtkDataObject::FIELD_ASSOCIATION_POINTS,
                               vtkDataSetAttributes::SCALARS);

  // by default process active point vectors
  this->SetInputArrayToProcess(1,0,0,vtkDataObject::FIELD_ASSOCIATION_POINTS,
                               vtkDataSetAttributes::VECTORS);
}

//----------------------------------------------------------------------------
int vtkSQTubeFilter::FillOutputPortInformation(
      int /*port*/,
      vtkInformation *info)
{
  info->Set(vtkDataObject::DATA_TYPE_NAME(), "vtkPolyData");
  return 1;
}

//----------------------------------------------------------------------------
int vtkSQTubeFilter::RequestData(
  vtkInformation *vtkNotUsed(request),
  vtkInformationVector **inputVector,
  vtkInformationVector *outputVector)
{
  // output
  vtkInformation *outInfo = outputVector->GetInformationObject(0);
  vtkPolyData *output
    = dynamic_cast<vtkPolyData*>(outInfo->Get(vtkDataObject::DATA_OBJECT()));
  vtkPointData *outPD=output->GetPointData();
  vtkCellData *outCD=output->GetCellData();

  // input
  vtkInformation *inInfo = inputVector[0]->GetInformationObject(0);
  vtkCellArray *inLines;
  vtkPointSet *input=dynamic_cast<vtkPointSet*>(inInfo->Get(vtkDataObject::DATA_OBJECT()));
  vtkPolyData *inputPd=dynamic_cast<vtkPolyData*>(input);
  vtkUnstructuredGrid *inputUg=dynamic_cast<vtkUnstructuredGrid*>(input);
  if (inputPd)
    {
    inLines=inputPd->GetLines();
    }
  else
  if (inputUg)
    {
    inLines=inputUg->GetCells();
    }
  else
    {
    vtkErrorMacro("Unsupported input data type " << input->GetClassName());
    return 1;
    }

  vtkPoints *inPts=input->GetPoints();
  if ((inLines==0) || (inPts==0))
    {
    // vtkErrorMacro("Invalid dataset, must have non-empty lines.");
    return 1;
    }

  vtkIdType numPts=inPts->GetNumberOfPoints();
  vtkIdType numLines=inLines->GetNumberOfCells();
  if ((numPts==0) || (numLines==0))
    {
    // nothing to do
    return 1;
    }

  vtkDebugMacro(<<"Creating tube");

  vtkPointData *pd=input->GetPointData();
  vtkCellData *cd=input->GetCellData();

  vtkDataArray *inScalars=this->GetInputArrayToProcess(0,inputVector);
  vtkDataArray *inVectors=this->GetInputArrayToProcess(1,inputVector);

  vtkIdType numNewPts, numNewCells;
  vtkPoints *newPts;
  vtkDataArray *inNormals;
  int deleteNormals=0;
  vtkFloatArray *newNormals;
  vtkIdType i;
  double range[2], maxSpeed=0;
  vtkCellArray *newStrips;
  vtkIdType npts=0, *pts=NULL;
  vtkIdType offset=0;
  vtkFloatArray *newTCoords=NULL;
  int abort=0;
  vtkIdType inCellId;
  double oldRadius=1.0;

  // Create the geometry and topology
  numNewPts = numPts * this->NumberOfSides;
  newPts = vtkPoints::New();
  newPts->Allocate(numNewPts);
  newNormals = vtkFloatArray::New();
  newNormals->SetName("TubeNormals");
  newNormals->SetNumberOfComponents(3);
  newNormals->Allocate(3*numNewPts);
  newStrips = vtkCellArray::New();
  newStrips->Allocate(newStrips->EstimateSize(1,(int)numNewPts));
  vtkCellArray *singlePolyline = vtkCellArray::New();

  // Point data: copy scalars, vectors, tcoords. Normals may be computed here.
  outPD->CopyNormalsOff();
  if ( (this->GenerateTCoords == VTK_TCOORDS_FROM_SCALARS && inScalars) ||
       this->GenerateTCoords == VTK_TCOORDS_FROM_LENGTH ||
       this->GenerateTCoords == VTK_TCOORDS_FROM_NORMALIZED_LENGTH )
    {
    newTCoords = vtkFloatArray::New();
    newTCoords->SetNumberOfComponents(2);
    newTCoords->Allocate(numNewPts);
    outPD->CopyTCoordsOff();
    }
  outPD->CopyAllocate(pd,numNewPts);

  int generateNormals = 0;
  if ( !(inNormals=pd->GetNormals()) || this->UseDefaultNormal )
    {
    deleteNormals = 1;
    inNormals = vtkFloatArray::New();
    inNormals->SetNumberOfComponents(3);
    inNormals->SetNumberOfTuples(numPts);

    if ( this->UseDefaultNormal )
      {
      for ( i=0; i < numPts; i++)
        {
        inNormals->SetTuple(i,this->DefaultNormal);
        }
      }
    else
      {
      // Normal generation has been moved to lower in the function.
      // This allows each different polylines to share vertices, but have
      // their normals (and hence their tubes) calculated independently
      generateNormals = 1;
      }
    }

  // If varying width, get appropriate info.
  //
  if ( inScalars )
    {
    inScalars->GetRange(range,0);
    if ((range[1] - range[0]) == 0.0)
      {
      if (this->VaryRadius == VTK_VARY_RADIUS_BY_SCALAR )
        {
        vtkWarningMacro(<< "Scalar range is zero!");
        }
      range[1] = range[0] + 1.0;
      }
    if (this->VaryRadius == VTK_VARY_RADIUS_BY_ABSOLUTE_SCALAR)
      {
      // temporarily set the radius to 1.0 so that radius*scalar = scalar
      oldRadius = this->Radius;
      this->Radius = 1.0;
      if (range[0] < 0.0)
        {
        vtkWarningMacro(<< "Scalar values fall below zero when using absolute radius values!");
        }
      }
    }
  if ( inVectors )
    {
    maxSpeed = inVectors->GetMaxNorm();
    }

  // Copy selected parts of cell data; certainly don't want normals
  //
  numNewCells = inLines->GetNumberOfCells() * this->NumberOfSides + 2;
  outCD->CopyNormalsOff();
  outCD->CopyAllocate(cd,numNewCells);

  //  Create points along each polyline that are connected into NumberOfSides
  //  triangle strips. Texture coordinates are optionally generated.
  //
  this->Theta = 2.0*vtkMath::Pi() / this->NumberOfSides;
  vtkPolyLine *lineNormalGenerator = vtkPolyLine::New();
  for (inCellId=0, inLines->InitTraversal();
       inLines->GetNextCell(npts,pts) && !abort; inCellId++)
    {
    this->UpdateProgress(((double)inCellId)/((double)numLines));
    abort = this->GetAbortExecute();

    if (npts < 2)
      {
      vtkWarningMacro(<< "Less than two points in line!");
      continue; //skip tubing this polyline
      }

    // If necessary calculate normals, each polyline calculates its
    // normals independently, avoiding conflicts at shared vertices.
    if (generateNormals)
      {
      singlePolyline->Reset(); //avoid instantiation
      singlePolyline->InsertNextCell(npts,pts);
      if ( !lineNormalGenerator->GenerateSlidingNormals(inPts,singlePolyline,
                                                        inNormals) )
        {
        vtkWarningMacro("Could not generate normals for line. "
                        "Skipping to next.");
        continue; //skip tubing this polyline
        }
      }

    // Generate the points around the polyline. The tube is not stripped
    // if the polyline is bad.
    //
    if ( !this->GeneratePoints(offset,npts,pts,inPts,newPts,pd,outPD,
                               newNormals,inScalars,range,inVectors,
                               maxSpeed,inNormals) )
      {
      vtkWarningMacro(<< "Could not generate points!");
      continue; //skip tubing this polyline
      }

    // Generate the strips for this polyline (including caps)
    //
    this->GenerateStrips(offset,npts,pts,inCellId,cd,outCD,newStrips);

    // Generate the texture coordinates for this polyline
    //
    if ( newTCoords )
      {
      this->GenerateTextureCoords(offset,npts,pts,inPts,inScalars,newTCoords);
      }

    // Compute the new offset for the next polyline
    offset = this->ComputeOffset(offset,npts);

    }//for all polylines

  singlePolyline->Delete();

  // reset the radius to ite orginal value if necessary
  if (this->VaryRadius == VTK_VARY_RADIUS_BY_ABSOLUTE_SCALAR)
    {
    this->Radius = oldRadius;
    }

  // Update ourselves
  //
  if ( deleteNormals )
    {
    inNormals->Delete();
    }

  if ( newTCoords )
    {
    outPD->SetTCoords(newTCoords);
    newTCoords->Delete();
    }

  output->SetPoints(newPts);
  newPts->Delete();

  output->SetStrips(newStrips);
  newStrips->Delete();

  outPD->SetNormals(newNormals);
  newNormals->Delete();
  lineNormalGenerator->Delete();

  output->Squeeze();

  return 1;
}

//----------------------------------------------------------------------------
int vtkSQTubeFilter::GeneratePoints(vtkIdType offset,
                                  vtkIdType npts, vtkIdType *pts,
                                  vtkPoints *inPts, vtkPoints *newPts,
                                  vtkPointData *pd, vtkPointData *outPD,
                                  vtkFloatArray *newNormals,
                                  vtkDataArray *inScalars, double range[2],
                                  vtkDataArray *inVectors, double maxSpeed,
                                  vtkDataArray *inNormals)
{
  vtkIdType j;
  int i, k;
  double p[3];
  double pNext[3];
  double sNext[3];
  double sPrev[3];
  double startCapNorm[3], endCapNorm[3];
  double n[3];
  double s[3];
  //double bevelAngle;
  double w[3];
  double nP[3];
  double sFactor=1.0;
  double normal[3];
  vtkIdType ptId=offset;

  // Use "averaged" segment to create beveled effect.
  // Watch out for first and last points.
  //
  for (j=0; j < npts; j++)
    {
    if ( j == 0 ) //first point
      {
      inPts->GetPoint(pts[0],p);
      inPts->GetPoint(pts[1],pNext);
      for (i=0; i<3; i++)
        {
        sNext[i] = pNext[i] - p[i];
        sPrev[i] = sNext[i];
        startCapNorm[i] = -sPrev[i];
        }
      vtkMath::Normalize(startCapNorm);
      }
    else if ( j == (npts-1) ) //last point
      {
      for (i=0; i<3; i++)
        {
        sPrev[i] = sNext[i];
        p[i] = pNext[i];
        endCapNorm[i] = sNext[i];
        }
      vtkMath::Normalize(endCapNorm);
      }
    else
      {
      for (i=0; i<3; i++)
        {
        p[i] = pNext[i];
        }
      inPts->GetPoint(pts[j+1],pNext);
      for (i=0; i<3; i++)
        {
        sPrev[i] = sNext[i];
        sNext[i] = pNext[i] - p[i];
        }
      }

    inNormals->GetTuple(pts[j], n);

    if ( vtkMath::Normalize(sNext) == 0.0 )
      {
      vtkWarningMacro(<<"Coincident points!");
      return 0;
      }

    for (i=0; i<3; i++)
      {
      s[i] = (sPrev[i] + sNext[i]) / 2.0; //average vector
      }
    // if s is zero then just use sPrev cross n
    if (vtkMath::Normalize(s) == 0.0)
      {
      vtkDebugMacro(<< "Using alternate bevel vector");
      vtkMath::Cross(sPrev,n,s);
      if (vtkMath::Normalize(s) == 0.0)
        {
        vtkDebugMacro(<< "Using alternate bevel vector");
        }
      }

/*    if ( (bevelAngle = vtkMath::Dot(sNext,sPrev)) > 1.0 )
      {
      bevelAngle = 1.0;
      }
    if ( bevelAngle < -1.0 )
      {
      bevelAngle = -1.0;
      }
    bevelAngle = acos((double)bevelAngle) / 2.0; //(0->90 degrees)
    if ( (bevelAngle = cos(bevelAngle)) == 0.0 )
      {
      bevelAngle = 1.0;
      }

    bevelAngle = this->Radius / bevelAngle; //keep tube constant radius
*/
    vtkMath::Cross(s,n,w);
    if ( vtkMath::Normalize(w) == 0.0)
      {
      vtkWarningMacro(<<"Bad normal s = " <<s[0]<<" "<<s[1]<<" "<< s[2]
                      << " n = " << n[0] << " " << n[1] << " " << n[2]);
      return 0;
      }

    vtkMath::Cross(w,s,nP); //create orthogonal coordinate system
    vtkMath::Normalize(nP);

    // Compute a scale factor based on scalars or vectors
    if ( inScalars && this->VaryRadius == VTK_VARY_RADIUS_BY_SCALAR )
      {
      sFactor = 1.0 + ((this->RadiusFactor - 1.0) *
                (inScalars->GetComponent(pts[j],0) - range[0])
                       / (range[1]-range[0]));
      }
    else if ( inVectors && this->VaryRadius == VTK_VARY_RADIUS_BY_VECTOR )
      {
      sFactor =
        sqrt((double)maxSpeed/vtkMath::Norm(inVectors->GetTuple(pts[j])));
      if ( sFactor > this->RadiusFactor )
        {
        sFactor = this->RadiusFactor;
        }
      }
    else if ( inScalars &&
              this->VaryRadius == VTK_VARY_RADIUS_BY_ABSOLUTE_SCALAR )
      {
      sFactor = inScalars->GetComponent(pts[j],0);
      if (sFactor < 0.0)
        {
        vtkWarningMacro(<<"Scalar value less than zero, skipping line");
        return 0;
        }
      }

    //create points around line
    if (this->SidesShareVertices)
      {
      for (k=0; k < this->NumberOfSides; k++)
        {
        for (i=0; i<3; i++)
          {
          normal[i] = w[i]*cos((double)k*this->Theta) +
            nP[i]*sin((double)k*this->Theta);
          s[i] = p[i] + this->Radius * sFactor * normal[i];
          }
        newPts->InsertPoint(ptId,s);
        newNormals->InsertTuple(ptId,normal);
        outPD->CopyData(pd,pts[j],ptId);
        ptId++;
        }//for each side
      }
    else
      {
      double n_left[3], n_right[3];
      for (k=0; k < this->NumberOfSides; k++)
        {
        for (i=0; i<3; i++)
          {
          // Create duplicate vertices at each point
          // and adjust the associated normals so that they are
          // oriented with the facets. This preserves the tube's
          // polygonal appearance, as if by flat-shading around the tube,
          // while still allowing smooth (gouraud) shading along the
          // tube as it bends.
          normal[i]  = w[i]*cos((double)(k+0.0)*this->Theta) +
            nP[i]*sin((double)(k+0.0)*this->Theta);
          n_right[i] = w[i]*cos((double)(k-0.5)*this->Theta) +
            nP[i]*sin((double)(k-0.5)*this->Theta);
          n_left[i]  = w[i]*cos((double)(k+0.5)*this->Theta) +
            nP[i]*sin((double)(k+0.5)*this->Theta);
          s[i] = p[i] + this->Radius * sFactor * normal[i];
          }
        newPts->InsertPoint(ptId,s);
        newNormals->InsertTuple(ptId,n_right);
        outPD->CopyData(pd,pts[j],ptId);
        newPts->InsertPoint(ptId+1,s);
        newNormals->InsertTuple(ptId+1,n_left);
        outPD->CopyData(pd,pts[j],ptId+1);
        ptId += 2;
        }//for each side
      }//else separate vertices
    }//for all points in polyline

  //Produce end points for cap. They are placed at tail end of points.
  if (this->Capping)
    {
    int numCapSides = this->NumberOfSides;
    int capIncr = 1;
    if ( ! this->SidesShareVertices )
      {
      numCapSides = 2 * this->NumberOfSides;
      capIncr = 2;
      }

    //the start cap
    for (k=0; k < numCapSides; k+=capIncr)
      {
      newPts->GetPoint(offset+k,s);
      newPts->InsertPoint(ptId,s);
      newNormals->InsertTuple(ptId,startCapNorm);
      outPD->CopyData(pd,pts[0],ptId);
      ptId++;
      }
    //the end cap
    int endOffset = (int)(offset + (npts-1)*this->NumberOfSides);
    if ( ! this->SidesShareVertices )
      {
      endOffset = (int)(offset + 2*(npts-1)*this->NumberOfSides);
      }
    for (k=0; k < numCapSides; k+=capIncr)
      {
      newPts->GetPoint(endOffset+k,s);
      newPts->InsertPoint(ptId,s);
      newNormals->InsertTuple(ptId,endCapNorm);
      outPD->CopyData(pd,pts[npts-1],ptId);
      ptId++;
      }
    }//if capping

  return 1;
}

//----------------------------------------------------------------------------
void vtkSQTubeFilter::GenerateStrips(vtkIdType offset, vtkIdType npts,
                                   vtkIdType* vtkNotUsed(pts),
                                   vtkIdType inCellId,
                                   vtkCellData *cd, vtkCellData *outCD,
                                   vtkCellArray *newStrips)
{
  vtkIdType i, outCellId;
  int k;
  int i1, i2, i3;

  if (this->SidesShareVertices)
    {
    for (k=this->Offset; k<(this->NumberOfSides+this->Offset);
         k+=this->OnRatio)
      {
      i1 = k % this->NumberOfSides;
      i2 = (k+1) % this->NumberOfSides;
      outCellId = newStrips->InsertNextCell(((int)npts*2));
      outCD->CopyData(cd,inCellId,outCellId);
      for (i=0; i < npts; i++)
        {
        i3 = (int)(i*this->NumberOfSides);
        newStrips->InsertCellPoint(offset+i2+i3);
        newStrips->InsertCellPoint(offset+i1+i3);
        }
      } //for each side of the tube
    }
  else
    {
    for (k=this->Offset; k<(this->NumberOfSides+this->Offset);
         k+=this->OnRatio)
      {
      i1 = 2*(k % this->NumberOfSides) + 1;
      i2 = 2*((k+1) % this->NumberOfSides);
      outCellId = newStrips->InsertNextCell((int)(npts*2));
      outCD->CopyData(cd,inCellId,outCellId);
      for (i=0; i < npts; i++)
        {
        i3 = ((int)i)*2*this->NumberOfSides;
        newStrips->InsertCellPoint(offset+i2+i3);
        newStrips->InsertCellPoint(offset+i1+i3);
        }
      } //for each side of the tube
    }

  // Take care of capping. The caps are n-sided polygons that can be
  // easily triangle stripped.
  if (this->Capping)
    {
    vtkIdType startIdx = offset + npts*this->NumberOfSides;
    vtkIdType idx;

    if ( ! this->SidesShareVertices )
      {
      startIdx = offset + 2*npts*this->NumberOfSides;
      }

    //The start cap
    outCellId = newStrips->InsertNextCell(this->NumberOfSides);
    outCD->CopyData(cd,inCellId,outCellId);
    newStrips->InsertCellPoint(startIdx);
    newStrips->InsertCellPoint(startIdx+1);
    for (i1=this->NumberOfSides-1, i2=2, k=0; k<(this->NumberOfSides-2); k++)
      {
      if ( (k%2) )
        {
        idx = startIdx + i2;
        newStrips->InsertCellPoint(idx);
        i2++;
        }
      else
        {
        idx = startIdx + i1;
        newStrips->InsertCellPoint(idx);
        i1--;
        }
      }

    //The end cap - reversed order to be consistent with normal
    startIdx += this->NumberOfSides;
    outCellId = newStrips->InsertNextCell(this->NumberOfSides);
    outCD->CopyData(cd,inCellId,outCellId);
    newStrips->InsertCellPoint(startIdx);
    newStrips->InsertCellPoint(startIdx+this->NumberOfSides-1);
    for (i1=this->NumberOfSides-2, i2=1, k=0; k<(this->NumberOfSides-2); k++)
      {
      if ( (k%2) )
        {
        idx = startIdx + i1;
        newStrips->InsertCellPoint(idx);
        i1--;
        }
      else
        {
        idx = startIdx + i2;
        newStrips->InsertCellPoint(idx);
        i2++;
        }
      }
    }
}

//----------------------------------------------------------------------------
void vtkSQTubeFilter::GenerateTextureCoords(vtkIdType offset,
                                          vtkIdType npts, vtkIdType *pts,
                                          vtkPoints *inPts,
                                          vtkDataArray *inScalars,
                                          vtkFloatArray *newTCoords)
{
  vtkIdType i;
  int k;
  double tc=0.0;

  int numSides = this->NumberOfSides;
  if ( ! this->SidesShareVertices )
    {
    numSides = 2 * this->NumberOfSides;
    }

  double s0, s;
  //The first texture coordinate is always 0.
  for ( k=0; k < numSides; k++)
    {
    newTCoords->InsertTuple2(offset+k,0.0,0.0);
    }
  if ( this->GenerateTCoords == VTK_TCOORDS_FROM_SCALARS )
    {
    s0 = inScalars->GetTuple1(pts[0]);
    for (i=1; i < npts; i++)
      {
      s = inScalars->GetTuple1(pts[i]);
      tc = (s - s0) / this->TextureLength;
      for ( k=0; k < numSides; k++)
        {
        newTCoords->InsertTuple2(offset+i*numSides+k,tc,0.0);
        }
      }
    }
  else if ( this->GenerateTCoords == VTK_TCOORDS_FROM_LENGTH )
    {
    double xPrev[3], x[3], len=0.0;
    inPts->GetPoint(pts[0],xPrev);
    for (i=1; i < npts; i++)
      {
      inPts->GetPoint(pts[i],x);
      len += sqrt(vtkMath::Distance2BetweenPoints(x,xPrev));
      tc = len / this->TextureLength;
      for ( k=0; k < numSides; k++)
        {
        newTCoords->InsertTuple2(offset+i*numSides+k,tc,0.0);
        }
      xPrev[0]=x[0]; xPrev[1]=x[1]; xPrev[2]=x[2];
      }
    }
  else if ( this->GenerateTCoords == VTK_TCOORDS_FROM_NORMALIZED_LENGTH )
    {
    double xPrev[3], x[3], length=0.0, len=0.0;
    inPts->GetPoint(pts[0],xPrev);
    for (i=1; i < npts; i++)
      {
      inPts->GetPoint(pts[i],x);
      length += sqrt(vtkMath::Distance2BetweenPoints(x,xPrev));
      xPrev[0]=x[0]; xPrev[1]=x[1]; xPrev[2]=x[2];
      }

    inPts->GetPoint(pts[0],xPrev);
    for (i=1; i < npts; i++)
      {
      inPts->GetPoint(pts[i],x);
      len += sqrt(vtkMath::Distance2BetweenPoints(x,xPrev));
      tc = len / length;
      for ( k=0; k < numSides; k++)
        {
        newTCoords->InsertTuple2(offset+i*2+k,tc,0.0);
        }
      xPrev[0]=x[0]; xPrev[1]=x[1]; xPrev[2]=x[2];
      }
    }

  // Capping, set the endpoints as appropriate
  if ( this->Capping )
    {
    int ik;
    vtkIdType startIdx = offset + npts*numSides;

    //start cap
    for (ik=0; ik < this->NumberOfSides; ik++)
      {
      newTCoords->InsertTuple2(startIdx+ik,0.0,0.0);
      }

    //end cap
    for (ik=0; ik < this->NumberOfSides; ik++)
      {
      newTCoords->InsertTuple2(startIdx+this->NumberOfSides+ik,tc,0.0);
      }
    }
}

// Compute the number of points in this tube
//----------------------------------------------------------------------------
vtkIdType vtkSQTubeFilter::ComputeOffset(vtkIdType offset, vtkIdType npts)
{
  if ( this->SidesShareVertices )
    {
    offset += this->NumberOfSides * npts;
    }
  else
    {
    offset += 2 * this->NumberOfSides * npts; //points are duplicated
    }

  if ( this->Capping )
    {
    offset += 2*this->NumberOfSides; //cap points are duplicated
    }

  return offset;
}

// Description:
// Return the method of varying tube radius descriptive character string.
//----------------------------------------------------------------------------
const char *vtkSQTubeFilter::GetVaryRadiusAsString(void)
{
  if ( this->VaryRadius == VTK_VARY_RADIUS_OFF )
    {
    return "VaryRadiusOff";
    }
  else if ( this->VaryRadius == VTK_VARY_RADIUS_BY_SCALAR )
    {
    return "VaryRadiusByScalar";
    }
  else if ( this->VaryRadius == VTK_VARY_RADIUS_BY_ABSOLUTE_SCALAR )
    {
    return "VaryRadiusByAbsoluteScalar";
    }
  else
    {
    return "VaryRadiusByVector";
    }
}

// Description:
// Return the method of generating the texture coordinates.
//----------------------------------------------------------------------------
const char *vtkSQTubeFilter::GetGenerateTCoordsAsString(void)
{
  if ( this->GenerateTCoords == VTK_TCOORDS_OFF )
    {
    return "GenerateTCoordsOff";
    }
  else if ( this->GenerateTCoords == VTK_TCOORDS_FROM_SCALARS )
    {
    return "GenerateTCoordsFromScalar";
    }
  else if ( this->GenerateTCoords == VTK_TCOORDS_FROM_LENGTH )
    {
    return "GenerateTCoordsFromLength";
    }
  else
    {
    return "GenerateTCoordsFromNormalizedLength";
    }
}

//----------------------------------------------------------------------------
void vtkSQTubeFilter::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os,indent);

  os << indent << "Radius: " << this->Radius << "\n";
  os << indent << "Vary Radius: " << this->GetVaryRadiusAsString() << endl;
  os << indent << "Radius Factor: " << this->RadiusFactor << "\n";
  os << indent << "Number Of Sides: " << this->NumberOfSides << "\n";
  os << indent << "On Ratio: " << this->OnRatio << "\n";
  os << indent << "Offset: " << this->Offset << "\n";

  os << indent << "Use Default Normal: "
     << (this->UseDefaultNormal ? "On\n" : "Off\n");
  os << indent << "Sides Share Vertices: "
     << (this->SidesShareVertices ? "On\n" : "Off\n");
  os << indent << "Default Normal: " << "( " << this->DefaultNormal[0] <<
     ", " << this->DefaultNormal[1] << ", " << this->DefaultNormal[2] <<
     " )\n";
  os << indent << "Capping: " << (this->Capping ? "On\n" : "Off\n");
  os << indent << "Generate TCoords: "
     << this->GetGenerateTCoordsAsString() << endl;
  os << indent << "Texture Length: " << this->TextureLength << endl;
}
