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

  Program:   Visualization Toolkit
  Module:    vtkButterflySubdivisionFilter.cxx
  Language:  C++
  Date:      $Date$
  Version:   $Revision$
  Thanks:    This work was supported bt PHS Research Grant No. 1 P41 RR13218-01
             from the National Center for Research Resources

Copyright (c) 1993-2000 Ken Martin, Will Schroeder, Bill Lorensen 
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

 * Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.

 * Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

 * Neither name of Ken Martin, Will Schroeder, or Bill Lorensen nor the names
   of any contributors may be used to endorse or promote products derived
   from this software without specific prior written permission.

 * Modified source versions must be plainly marked as such, and must not be
   misrepresented as being the original software.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

=========================================================================*/
#include "vtkButterflySubdivisionFilter.h"
#include "vtkEdgeTable.h"
#include "vtkObjectFactory.h"

static float butterflyWeights[8] =
  {.5, .5, .125, .125, -.0625, -.0625, -.0625, -.0625};

vtkButterflySubdivisionFilter* vtkButterflySubdivisionFilter::New()
{
  // First try to create the object from the vtkObjectFactory
  vtkObject* ret = vtkObjectFactory::CreateInstance("vtkButterflySubdivisionFilter");
  if(ret)
    {
    return (vtkButterflySubdivisionFilter*)ret;
    }
  // If the factory was unable to create the object, then create it here.
  return new vtkButterflySubdivisionFilter;
}

void vtkButterflySubdivisionFilter::GenerateSubdivisionPoints (vtkPolyData *inputDS, vtkIntArray *edgeData, vtkPoints *outputPts, vtkPointData *outputPD)
{
  float *weights, *weights1, *weights2;
  int *pts;
  int cellId, edgeId, newId;
  int i, j;
  int npts;
  int p1, p2;
  int valence1, valence2;
  vtkCellArray *inputPolys=inputDS->GetPolys();
  vtkEdgeTable *edgeTable;
  vtkIdList *cellIds = vtkIdList::New();
  vtkIdList *p1CellIds = vtkIdList::New();
  vtkIdList *p2CellIds = vtkIdList::New();
  vtkIdList *stencil = vtkIdList::New();
  vtkIdList *stencil1 = vtkIdList::New();
  vtkIdList *stencil2 = vtkIdList::New();
  vtkPoints *inputPts=inputDS->GetPoints();
  vtkPointData *inputPD=inputDS->GetPointData();

  weights = new float[256];
  weights1 = new float[256];
  weights2 = new float[256];

  // Create an edge table to keep track of which edges we've processed
  edgeTable = vtkEdgeTable::New();
  edgeTable->InitEdgeInsertion(inputDS->GetNumberOfPoints());

  // Generate new points for subdivisions surface
  for (cellId=0, inputPolys->InitTraversal(); inputPolys->GetNextCell(npts, pts); cellId++)
    {
    if ( inputDS->GetCellType(cellId) != VTK_TRIANGLE )
      {
      continue;
      }

    p1 = pts[2];
    p2 = pts[0];

    for (edgeId=0; edgeId < 3; edgeId++)
      {
      // Do we need to  create a point on this edge?
      if (edgeTable->IsEdge (p1, p2) == -1)
	{
        outputPD->CopyData (inputPD, p1, p1);
        outputPD->CopyData (inputPD, p2, p2);
	edgeTable->InsertEdge (p1, p2);

        inputDS->GetCellEdgeNeighbors (-1, p1, p2, cellIds);
        // If this is a boundary edge. we need to use a special subdivision rule
        if (cellIds->GetNumberOfIds() == 1)
          {
 	  // Compute new POsition and PointData using the same subdivision scheme
	  this->GenerateBoundaryStencil (p1, p2,
					 inputDS, stencil, weights);
          } // boundary edge
	else
	  {
	  // find the valence of the two points
	  inputDS->GetPointCells (p1, p1CellIds);
	  valence1 = p1CellIds->GetNumberOfIds();
	  inputDS->GetPointCells (p2, p2CellIds);
	  valence2 = p2CellIds->GetNumberOfIds();

	  if (valence1 == 6 && valence2 == 6)
	    {
	    this->GenerateButterflyStencil (p1, p2,
					    inputDS, stencil, weights);
	    }
	  else if (valence1 == 6 && valence2 != 6)
	    {
	    this->GenerateLoopStencil (p2, p1,
				       inputDS, stencil, weights);
	    }
	  else if (valence1 != 6 && valence2 == 6)
	    {
	    this->GenerateLoopStencil (p1, p2,
				       inputDS, stencil, weights);
	    }
	  else
	    {
	    // Edge connects two extraordinary vertices
	    this->GenerateLoopStencil (p2, p1,
				       inputDS, stencil1, weights1);
	    this->GenerateLoopStencil (p1, p2,
				       inputDS, stencil2, weights2);
	    // combine the two stencils and halve the weights
	    int total = stencil1->GetNumberOfIds() + stencil2->GetNumberOfIds();
	    stencil->SetNumberOfIds (total);

	    j = 0;
	    for (i = 0; i < stencil1->GetNumberOfIds(); i++)
	      {
	      stencil->InsertId(j, stencil1->GetId(i));
	      weights[j++] = weights1[i] * .5;
	      }
	    for (i = 0; i < stencil2->GetNumberOfIds(); i++)
	      {
	      stencil->InsertId(j, stencil2->GetId(i));
	      weights[j++] = weights2[i] * .5;
	      }
	    }
	  }
	  newId = this->InterpolatePosition (inputPts, outputPts, stencil, weights);
	  outputPD->InterpolatePoint (inputPD, newId, stencil, weights);
	}
      else // we have already created a point on this edge. find it
	{
	newId = this->FindEdge (inputDS, cellId, p1, p2, edgeData, cellIds);
	}
      edgeData->InsertComponent(cellId,edgeId,newId);
      p1 = p2;
      if (edgeId < 2)
	{
	p2 = pts[edgeId + 1];
	}
      } // each interior edge
    } // each cell

  // cleanup
  delete [] weights; delete [] weights1; delete [] weights2;
  edgeTable->Delete();
  stencil->Delete (); stencil1->Delete (); stencil2->Delete ();
  cellIds->Delete();
  p1CellIds->Delete();
  p2CellIds->Delete();
}

void vtkButterflySubdivisionFilter::GenerateLoopStencil (int p1, int p2, vtkPolyData *polys, vtkIdList *stencilIds, float *weights)
{
  vtkIdList *cellIds = vtkIdList::New();
  vtkCell *cell;
  int j;
  int startCell, nextCell;
  int p, tp2;
  int shift[255];
  int processed = 0;
  int boundary = 0;

  // Find another cell with this edge (we assume there is just one)
  polys->GetCellEdgeNeighbors (-1, p1, p2, cellIds);
  startCell = cellIds->GetId(0);

  stencilIds->Reset();
  stencilIds->InsertNextId (p2);
  shift[0] = 0;
  
  // Walk around the loop and get cells
  nextCell = cellIds->GetId(1);
  tp2 = p2;
  boundary = 0;
  while (nextCell != startCell)
    {
    cell = polys->GetCell(nextCell);
    p = -1;
    for (int i = 0; i < 3; i++)
      {
      if ((p = cell->GetPointId(i)) != p1 && cell->GetPointId(i) != tp2)
        {
        break;
        }
      }
    tp2 = p;
    stencilIds->InsertNextId (tp2);
    processed++;
    shift[processed] = processed;
    polys->GetCellEdgeNeighbors (nextCell, p1, tp2, cellIds);
    if (cellIds->GetNumberOfIds() != 1)
      {
      boundary = 1;
       break;
      }
    nextCell = cellIds->GetId(0);
    }

  // If p1 or p2 is on the boundary, use the butterfly stencil with reflected vertices.
  if (boundary)
    {
    this->GenerateButterflyStencil (p1, p2,
				    polys, stencilIds, weights);
    cellIds->Delete();
    return;
    }

  // Generate weights
#define VTK_PI 3.14159265358979
  int K = stencilIds->GetNumberOfIds();
  if (K >= 5)
    {
    for (j = 0; j < K; j++)
      {
      weights[j] = (.25 +  cos (2.0 * VTK_PI * (float) shift[j] / (float) K)
		   + .5 * cos (4.0 * VTK_PI * (float) shift[j] / (float) K)) / (float) K;
      }
    }
  else if (K == 4)
    {
    static float weights4[4] = {3.0/8.0, 0.0, -1.0/8.0, 0.0};
    weights[0] = weights4[abs(shift[0])];
    weights[1] = weights4[abs(shift[1])];
    weights[2] = weights4[abs(shift[2])];
    weights[3] = weights4[abs(shift[3])];
    }
  else if (K == 3)
    {
    static float weights3[3] = {5.0/12.0, -1.0/12.0, -1.0/12.0};
    weights[0] = weights3[abs(shift[0])];
    weights[1] = weights3[abs(shift[1])];
    weights[2] = weights3[abs(shift[2])];
    }
  else
    {  // K == 2. p1 must be on a boundary edge,
    cell = polys->GetCell(startCell);
    p = -1;
    for (int i = 0; i < 3; i++)
      {
      if ((p = cell->GetPointId(i)) != p1 && cell->GetPointId(i) != p2)
        {
        break;
        }
      }
    p2 = p;
    stencilIds->InsertNextId (p2);
    weights[0] = 5.0 / 12.0;
    weights[1] = -1.0 / 12.0;
    weights[2] = -1.0 / 12.0;
    }
  // add in the extraordinary vertex
  weights[stencilIds->GetNumberOfIds()] = .75;
  stencilIds->InsertNextId (p1);

  cellIds->Delete();
}

void vtkButterflySubdivisionFilter::GenerateBoundaryStencil
    (int p1, int p2, vtkPolyData *polys,
     vtkIdList *stencilIds, float *weights)
{
  vtkIdList *cellIds = vtkIdList::New();
  int *cells;
  unsigned short ncells;
  int *pts;
  int npts;
  int i, j;
  int p0, p3;

  // find a boundary edge that uses p1 other than the one containing p2
  polys->GetPointCells (p1, ncells, cells);
  p0 = -1;
  for (i = 0; i < ncells && p0 == -1; i++)
    {
    polys->GetCellPoints (cells[i], npts, pts);
    for (j = 0; j < npts; j++)
      {
      if (pts[j] == p1 || pts[j] == p2)
	{
	continue;
	}
      polys->GetCellEdgeNeighbors (-1, p1, pts[j], cellIds);
      if (cellIds->GetNumberOfIds() == 1)
	{
	p0 = pts[j];
	break;
	}
      }
    }
  // find a boundary edge that uses p2 other than the one containing p1
  polys->GetPointCells (p2, ncells, cells);
  p3 = -1;
  for (i = 0; i < ncells && p3 == -1; i++)
    {
    polys->GetCellPoints (cells[i], npts, pts);
    for (j = 0; j < npts; j++)
      {
      if (pts[j] == p1 || pts[j] == p2 || pts[j] == p0)
	{
	continue;
	}
      polys->GetCellEdgeNeighbors (-1, p2, pts[j], cellIds);
      if (cellIds->GetNumberOfIds() == 1)
	{
	p3 = pts[j];
	break;
	}
      }
    }
  stencilIds->SetNumberOfIds (4);
  stencilIds->SetId (0, p0);
  stencilIds->SetId (1, p1);
  stencilIds->SetId (2, p2);
  stencilIds->SetId (3, p3);
  weights[0] = -.0625;
  weights[1] = .5625;
  weights[2] = .5625;
  weights[3] = -.0625;
  
  cellIds->Delete();
}

void vtkButterflySubdivisionFilter::GenerateButterflyStencil (int p1, int p2, vtkPolyData *polys, vtkIdList *stencilIds, float *weights)
{
  vtkIdList *cellIds = vtkIdList::New();
  vtkCell *cell;
  int i;
  int cell0, cell1;
  int p, p3, p4, p5, p6, p7, p8;

  polys->GetCellEdgeNeighbors (-1, p1, p2, cellIds);
  cell0 = cellIds->GetId(0);
  cell1 = cellIds->GetId(1);

  cell = polys->GetCell(cell0);
  p3 = -1;
  for (i = 0; i < 3; i++)
    {
    if ((p = cell->GetPointId(i)) != p1 && cell->GetPointId(i) != p2)
      {
      p3 = p;
      break;
      }
    }
  cell = polys->GetCell(cell1);
  p4 = -1;
  for (i = 0; i < 3; i++)
    {
    if ((p = cell->GetPointId(i)) != p1 && cell->GetPointId(i) != p2)
      {
      p4 = p;
      break;
      }
    }

  polys->GetCellEdgeNeighbors (cell0, p1, p3, cellIds);
  p5 = -1;
  if (cellIds->GetNumberOfIds() > 0)
    {
    cell = polys->GetCell(cellIds->GetId(0));
    for (i = 0; i < 3; i++)
      {
      if ((p = cell->GetPointId(i)) != p1 && cell->GetPointId(i) != p3)
        {
	p5 = p;
        break;
        }
      }
    }

  polys->GetCellEdgeNeighbors (cell0, p2, p3, cellIds);
  p6 = -1;
  if (cellIds->GetNumberOfIds() > 0)
    {
    cell = polys->GetCell(cellIds->GetId(0));
    for (i = 0; i < 3; i++)
      {
      if ((p = cell->GetPointId(i)) != p2 && cell->GetPointId(i) != p3)
        {
	p6 = p;
        break;
        }
      }
    }

  polys->GetCellEdgeNeighbors (cell1, p1, p4, cellIds);
  p7 = -1;
  if (cellIds->GetNumberOfIds() > 0)
    {
    cell = polys->GetCell(cellIds->GetId(0));
    for (i = 0; i < 3; i++)
      {
      if ((p = cell->GetPointId(i)) != p1 && cell->GetPointId(i) != p4)
        {
	p7 = p;
        break;
        }
      }
    }

  p8 = -1;
  polys->GetCellEdgeNeighbors (cell1, p2, p4, cellIds);
  if (cellIds->GetNumberOfIds() > 0)
    {
    cell = polys->GetCell(cellIds->GetId(0));
    for (i = 0; i < 3; i++)
      {
      if ((p = cell->GetPointId(i)) != p2 && cell->GetPointId(i) != p4)
        {
	p8= p;
        break;
        }
      }
    }

  stencilIds->SetNumberOfIds (8);
  stencilIds->SetId(0, p1);
  stencilIds->SetId(1, p2);
  stencilIds->SetId(2, p3);
  stencilIds->SetId(3, p4);
  if (p5 != -1)
    {
    stencilIds->SetId(4, p5);
    }
  else if (p4 != -1)
    {
    stencilIds->SetId(4, p4);
    }
  else
    {
      vtkWarningMacro (<< "bad p5, p4 " << p5  << ", " << p4);
    }

  if (p6 != -1)
    {
    stencilIds->SetId(5, p6);
    }
  else if (p4 != -1)
    {
    stencilIds->SetId(5, p4);
    }
  else
    {
      vtkWarningMacro (<< "bad p5, p4 " << p5 << ", " << p4);
    }

  if (p7 != -1)
    {
    stencilIds->SetId(6, p7);
    }
  else if (p3 != -1)
    {
    stencilIds->SetId(6, p3);
    }
  else
    {
      vtkWarningMacro (<< "bad p7, p3 " << p7 << ", " << p3);
    }

  if (p8 != -1)
    {
    stencilIds->SetId(7, p8);
    }
  else if (p3 != -1)
    {
    stencilIds->SetId(7, p3);
    }
  else
    {
      vtkWarningMacro (<< "bad p7, p8 " << p7 << ", " << p3);
    }


  for (i = 0; i < stencilIds->GetNumberOfIds (); i++)
    {
    weights[i] = butterflyWeights[i];
    }
  cellIds->Delete();
}
