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

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkMarchingCubes.cxx,v $
  Language:  C++
  Date:      $Date: 2002/12/26 18:18:12 $
  Version:   $Revision: 1.83 $

  Copyright (c) 1993-2002 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.

     THIS CLASS IS PATENTED UNDER UNITED STATES PATENT NUMBER 4,710,876
     "System and Method for the Display of Surface Structures Contained
     Within the Interior Region of a Solid Body".
     Application of this software for commercial purposes requires 
     a license grant from GE. Contact:

         Carl B. Horton
         Sr. Counsel, Intellectual Property
         3000 N. Grandview Blvd., W-710
         Waukesha, WI  53188
         Phone:  (262) 513-4022
         E-Mail: Carl.Horton@med.ge.com

     for more information.

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

#include "vtkCellArray.h"
#include "vtkCharArray.h"
#include "vtkDoubleArray.h"
#include "vtkFloatArray.h"
#include "vtkIntArray.h"
#include "vtkLongArray.h"
#include "vtkMarchingCubesCases.h"
#include "vtkMath.h"
#include "vtkMergePoints.h"
#include "vtkObjectFactory.h"
#include "vtkPointData.h"
#include "vtkPolyData.h"
#include "vtkShortArray.h"
#include "vtkStructuredPoints.h"
#include "vtkUnsignedCharArray.h"
#include "vtkUnsignedIntArray.h"
#include "vtkUnsignedLongArray.h"
#include "vtkUnsignedShortArray.h"

vtkCxxRevisionMacro(vtkMarchingCubes, "$Revision: 1.83 $");
vtkStandardNewMacro(vtkMarchingCubes);

// Description:
// Construct object with initial range (0,1) and single contour value
// of 0.0. ComputeNormal is on, ComputeGradients is off and ComputeScalars is on.
vtkMarchingCubes::vtkMarchingCubes()
{
  this->ContourValues = vtkContourValues::New();
  this->ComputeNormals = 1;
  this->ComputeGradients = 0;
  this->ComputeScalars = 1;
  this->Locator = NULL;
}

vtkMarchingCubes::~vtkMarchingCubes()
{
  this->ContourValues->Delete();
  if ( this->Locator )
    {
    this->Locator->UnRegister(this);
    this->Locator = NULL;
    }
}

// Description:
// Overload standard modified time function. If contour values are modified,
// then this object is modified as well.
unsigned long vtkMarchingCubes::GetMTime()
{
  unsigned long mTime=this->vtkStructuredPointsToPolyDataFilter::GetMTime();
  unsigned long mTime2=this->ContourValues->GetMTime();

  mTime = ( mTime2 > mTime ? mTime2 : mTime );
  if (this->Locator)
    {
    mTime2=this->Locator->GetMTime();
    mTime = ( mTime2 > mTime ? mTime2 : mTime );
    }

  return mTime;
}

// Calculate the gradient using central difference.
// NOTE: We calculate the negative of the gradient for efficiency
template <class T>
void vtkMarchingCubesComputePointGradient(int i, int j, int k, T *s, int dims[3], 
                                          int sliceSize, float Spacing[3], float n[3])
{
  float sp, sm;

  // x-direction
  if ( i == 0 )
    {
    sp = s[i+1 + j*dims[0] + k*sliceSize];
    sm = s[i + j*dims[0] + k*sliceSize];
    n[0] = (sm - sp) / Spacing[0];
    }
  else if ( i == (dims[0]-1) )
    {
    sp = s[i + j*dims[0] + k*sliceSize];
    sm = s[i-1 + j*dims[0] + k*sliceSize];
    n[0] = (sm - sp) / Spacing[0];
    }
  else
    {
    sp = s[i+1 + j*dims[0] + k*sliceSize];
    sm = s[i-1 + j*dims[0] + k*sliceSize];
    n[0] = 0.5 * (sm - sp) / Spacing[0];
    }

  // y-direction
  if ( j == 0 )
    {
    sp = s[i + (j+1)*dims[0] + k*sliceSize];
    sm = s[i + j*dims[0] + k*sliceSize];
    n[1] = (sm - sp) / Spacing[1];
    }
  else if ( j == (dims[1]-1) )
    {
    sp = s[i + j*dims[0] + k*sliceSize];
    sm = s[i + (j-1)*dims[0] + k*sliceSize];
    n[1] = (sm - sp) / Spacing[1];
    }
  else
    {
    sp = s[i + (j+1)*dims[0] + k*sliceSize];
    sm = s[i + (j-1)*dims[0] + k*sliceSize];
    n[1] = 0.5 * (sm - sp) / Spacing[1];
    }

  // z-direction
  if ( k == 0 )
    {
    sp = s[i + j*dims[0] + (k+1)*sliceSize];
    sm = s[i + j*dims[0] + k*sliceSize];
    n[2] = (sm - sp) / Spacing[2];
    }
  else if ( k == (dims[2]-1) )
    {
    sp = s[i + j*dims[0] + k*sliceSize];
    sm = s[i + j*dims[0] + (k-1)*sliceSize];
    n[2] = (sm - sp) / Spacing[2];
    }
  else
    {
    sp = s[i + j*dims[0] + (k+1)*sliceSize];
    sm = s[i + j*dims[0] + (k-1)*sliceSize];
    n[2] = 0.5 * (sm - sp) / Spacing[2];
    }
}

//
// Contouring filter specialized for volumes and "short int" data values.  
//
template <class T>
void vtkMarchingCubesComputeGradient(vtkMarchingCubes *self,T *scalars, int dims[3], 
                                     float origin[3], float Spacing[3],
                                     vtkPointLocator *locator, 
                                     vtkDataArray *newScalars, 
                                     vtkDataArray *newGradients, 
                                     vtkDataArray *newNormals, 
                                     vtkCellArray *newPolys, float *values, 
                                     int numValues)
{
  float s[8], value;
  int i, j, k, sliceSize;
  static int CASE_MASK[8] = {1,2,4,8,16,32,64,128};
  vtkMarchingCubesTriangleCases *triCase, *triCases;
  EDGE_LIST  *edge;
  int contNum, jOffset, kOffset, idx, ii, index, *vert;
  vtkIdType ptIds[3];
  int ComputeNormals = newNormals != NULL;
  int ComputeGradients = newGradients != NULL;
  int ComputeScalars = newScalars != NULL;
  int NeedGradients;
  float t, *x1, *x2, x[3], *n1, *n2, n[3], min, max;
  float pts[8][3], gradients[8][3], xp, yp, zp;
  static int edges[12][2] = { {0,1}, {1,2}, {3,2}, {0,3},
                              {4,5}, {5,6}, {7,6}, {4,7},
                              {0,4}, {1,5}, {3,7}, {2,6}};

  triCases =  vtkMarchingCubesTriangleCases::GetCases();

//
// Get min/max contour values
//
  if ( numValues < 1 )
    {
    return;
    }
  for ( min=max=values[0], i=1; i < numValues; i++)
    {
    if ( values[i] < min )
      {
      min = values[i];
      }
    if ( values[i] > max )
      {
      max = values[i];
      }
    }
//
// Traverse all voxel cells, generating triangles and point gradients
// using marching cubes algorithm.
//  
  sliceSize = dims[0] * dims[1];
  for ( k=0; k < (dims[2]-1); k++)
    {
    self->UpdateProgress ((float) k / ((float) dims[2] - 1));
    if (self->GetAbortExecute())
      {
      break;
      }
    kOffset = k*sliceSize;
    pts[0][2] = origin[2] + k*Spacing[2];
    zp = origin[2] + (k+1)*Spacing[2];
    for ( j=0; j < (dims[1]-1); j++)
      {
      jOffset = j*dims[0];
      pts[0][1] = origin[1] + j*Spacing[1];
      yp = origin[1] + (j+1)*Spacing[1];
      for ( i=0; i < (dims[0]-1); i++)
        {
        //get scalar values
        idx = i + jOffset + kOffset;
        s[0] = scalars[idx];
        s[1] = scalars[idx+1];
        s[2] = scalars[idx+1 + dims[0]];
        s[3] = scalars[idx + dims[0]];
        s[4] = scalars[idx + sliceSize];
        s[5] = scalars[idx+1 + sliceSize];
        s[6] = scalars[idx+1 + dims[0] + sliceSize];
        s[7] = scalars[idx + dims[0] + sliceSize];

        if ( (s[0] < min && s[1] < min && s[2] < min && s[3] < min &&
        s[4] < min && s[5] < min && s[6] < min && s[7] < min) ||
        (s[0] > max && s[1] > max && s[2] > max && s[3] > max &&
        s[4] > max && s[5] > max && s[6] > max && s[7] > max) )
          {
          continue; // no contours possible
          }

        //create voxel points
        pts[0][0] = origin[0] + i*Spacing[0];
        xp = origin[0] + (i+1)*Spacing[0];

        pts[1][0] = xp;
        pts[1][1] = pts[0][1];
        pts[1][2] = pts[0][2];

        pts[2][0] = xp;
        pts[2][1] = yp;
        pts[2][2] = pts[0][2];

        pts[3][0] = pts[0][0];
        pts[3][1] = yp;
        pts[3][2] = pts[0][2];

        pts[4][0] = pts[0][0];
        pts[4][1] = pts[0][1];
        pts[4][2] = zp;

        pts[5][0] = xp;
        pts[5][1] = pts[0][1];
        pts[5][2] = zp;

        pts[6][0] = xp;
        pts[6][1] = yp;
        pts[6][2] = zp;

        pts[7][0] = pts[0][0];
        pts[7][1] = yp;
        pts[7][2] = zp;

        NeedGradients = ComputeGradients || ComputeNormals;

        //create gradients if needed
        if (NeedGradients)
          {
          vtkMarchingCubesComputePointGradient(i,j,k, scalars, dims, sliceSize, Spacing, gradients[0]);
          vtkMarchingCubesComputePointGradient(i+1,j,k, scalars, dims, sliceSize, Spacing, gradients[1]);
          vtkMarchingCubesComputePointGradient(i+1,j+1,k, scalars, dims, sliceSize, Spacing, gradients[2]);
          vtkMarchingCubesComputePointGradient(i,j+1,k, scalars, dims, sliceSize, Spacing, gradients[3]);
          vtkMarchingCubesComputePointGradient(i,j,k+1, scalars, dims, sliceSize, Spacing, gradients[4]);
          vtkMarchingCubesComputePointGradient(i+1,j,k+1, scalars, dims, sliceSize, Spacing, gradients[5]);
          vtkMarchingCubesComputePointGradient(i+1,j+1,k+1, scalars, dims, sliceSize, Spacing, gradients[6]);
          vtkMarchingCubesComputePointGradient(i,j+1,k+1, scalars, dims, sliceSize, Spacing, gradients[7]);
          }
        for (contNum=0; contNum < numValues; contNum++)
          {
          value = values[contNum];
          // Build the case table
          for ( ii=0, index = 0; ii < 8; ii++)
            {
            if ( s[ii] >= value )
              {
              index |= CASE_MASK[ii];
              }
            }
          if ( index == 0 || index == 255 ) //no surface
            {
            continue;
            }

          triCase = triCases+ index;
          edge = triCase->edges;

          for ( ; edge[0] > -1; edge += 3 )
            {
            for (ii=0; ii<3; ii++) //insert triangle
              {
              vert = edges[edge[ii]];
              t = (value - s[vert[0]]) / (s[vert[1]] - s[vert[0]]);
              x1 = pts[vert[0]];
              x2 = pts[vert[1]];
              x[0] = x1[0] + t * (x2[0] - x1[0]);
              x[1] = x1[1] + t * (x2[1] - x1[1]);
              x[2] = x1[2] + t * (x2[2] - x1[2]);

              // check for a new point
              if ( locator->InsertUniquePoint(x, ptIds[ii]) )
                  {
                  if (NeedGradients)
                    {
                    n1 = gradients[vert[0]];
                    n2 = gradients[vert[1]];
                    n[0] = n1[0] + t * (n2[0] - n1[0]);
                    n[1] = n1[1] + t * (n2[1] - n1[1]);
                    n[2] = n1[2] + t * (n2[2] - n1[2]);
                    }
                  if (ComputeScalars)
                    {
                    newScalars->InsertTuple(ptIds[ii],&value);
                    }
                  if (ComputeGradients)
                    {
                    newGradients->InsertTuple(ptIds[ii],n);
                    }
                  if (ComputeNormals)
                    {
                    vtkMath::Normalize(n);
                    newNormals->InsertTuple(ptIds[ii],n);
                    }   
                  }
              }
            // check for degenerate triangle
            if ( ptIds[0] != ptIds[1] &&
                 ptIds[0] != ptIds[2] &&
                 ptIds[1] != ptIds[2] )
                {
                newPolys->InsertNextCell(3,ptIds);
                }
            }//for each triangle
          }//for all contours
        }//for i
      }//for j
    }//for k
}

//
// Contouring filter specialized for volumes and "short int" data values.  
//
void vtkMarchingCubes::Execute()
{
  vtkPoints *newPts;
  vtkCellArray *newPolys;
  vtkFloatArray *newScalars;
  vtkFloatArray *newNormals;
  vtkFloatArray *newGradients;
  vtkImageData *input = this->GetInput();
  vtkPointData *pd;
  vtkDataArray *inScalars;
  int dims[3];
  int estimatedSize;
  float Spacing[3], origin[3];
  float bounds[6];
  vtkPolyData *output = this->GetOutput();
  int numContours=this->ContourValues->GetNumberOfContours();
  float *values=this->ContourValues->GetValues();
  
  vtkDebugMacro(<< "Executing marching cubes");

//
// Initialize and check input
//
  if (input == NULL)
    {
    vtkErrorMacro(<<"Input is NULL");
    return;
    }
  pd=input->GetPointData();
  if (pd ==NULL)
    {
    vtkErrorMacro(<<"PointData is NULL");
    return;
    }
  inScalars=pd->GetScalars();
  if ( inScalars == NULL )
    {
    vtkErrorMacro(<<"Scalars must be defined for contouring");
    return;
    }

  if ( input->GetDataDimension() != 3 )
    {
    vtkErrorMacro(<<"Cannot contour data of dimension != 3");
    return;
    }
  input->GetDimensions(dims);
  input->GetOrigin(origin);
  input->GetSpacing(Spacing);

  // estimate the number of points from the volume dimensions
  estimatedSize = (int) pow ((double) (dims[0] * dims[1] * dims[2]), .75);
  estimatedSize = estimatedSize / 1024 * 1024; //multiple of 1024
  if (estimatedSize < 1024)
    {
    estimatedSize = 1024;
    }
  vtkDebugMacro(<< "Estimated allocation size is " << estimatedSize);
  newPts = vtkPoints::New(); newPts->Allocate(estimatedSize,estimatedSize/2);
  // compute bounds for merging points
  for ( int i=0; i<3; i++)
    {
    bounds[2*i] = origin[i];
    bounds[2*i+1] = origin[i] + (dims[i]-1) * Spacing[i];
    }
  if ( this->Locator == NULL )
    {
    this->CreateDefaultLocator();
    }
  this->Locator->InitPointInsertion (newPts, bounds, estimatedSize);

  if (this->ComputeNormals)
    {
    newNormals = vtkFloatArray::New();
    newNormals->SetNumberOfComponents(3);
    newNormals->Allocate(3*estimatedSize,3*estimatedSize/2);
    }
  else
    {
    newNormals = NULL;
    }

  if (this->ComputeGradients)
    {
    newGradients = vtkFloatArray::New();
    newGradients->SetNumberOfComponents(3);
    newGradients->Allocate(3*estimatedSize,3*estimatedSize/2);
    }
  else
    {
    newGradients = NULL;
    }

  newPolys = vtkCellArray::New();
  newPolys->Allocate(newPolys->EstimateSize(estimatedSize,3));

  if (this->ComputeScalars)
    {
    newScalars = vtkFloatArray::New();
    newScalars->Allocate(estimatedSize,estimatedSize/2);
    }
  else
    {
    newScalars = NULL;
    }

  if (inScalars->GetNumberOfComponents() == 1 )
    {
    switch (inScalars->GetDataType())
      {
      case VTK_CHAR:
        {
        char *scalars = static_cast<vtkCharArray *>(inScalars)->GetPointer(0);
        vtkMarchingCubesComputeGradient(this,scalars,dims,origin,Spacing,this->Locator,
                      newScalars,newGradients,
                      newNormals,newPolys,values,numContours);
        }
      break;
      case VTK_UNSIGNED_CHAR:
        {
        unsigned char *scalars = static_cast<vtkUnsignedCharArray *>(inScalars)->GetPointer(0);
        vtkMarchingCubesComputeGradient(this,scalars,dims,origin,Spacing,this->Locator,
                      newScalars,newGradients,
                      newNormals,newPolys,values,numContours);
        }
        break;
      case VTK_SHORT:
        {
        short *scalars = static_cast<vtkShortArray *>(inScalars)->GetPointer(0);
        vtkMarchingCubesComputeGradient(this,scalars,dims,origin,Spacing,this->Locator,
                      newScalars,newGradients,
                      newNormals,newPolys,values,numContours);
        }
      break;
      case VTK_UNSIGNED_SHORT:
        {
        unsigned short *scalars = static_cast<vtkUnsignedShortArray *>(inScalars)->GetPointer(0);
        vtkMarchingCubesComputeGradient(this,scalars,dims,origin,Spacing,this->Locator,
                      newScalars,newGradients,
                      newNormals,newPolys,values,numContours);
        }
      break;
      case VTK_INT:
        {
        int *scalars = static_cast<vtkIntArray *>(inScalars)->GetPointer(0);
        vtkMarchingCubesComputeGradient(this,scalars,dims,origin,Spacing,this->Locator,
                      newScalars,newGradients,
                      newNormals,newPolys,values,numContours);
        }
      break;
      case VTK_UNSIGNED_INT:
        {
        unsigned int *scalars = static_cast<vtkUnsignedIntArray *>(inScalars)->GetPointer(0);
        vtkMarchingCubesComputeGradient(this,scalars,dims,origin,Spacing,this->Locator,
                      newScalars,newGradients,
                      newNormals,newPolys,values,numContours);
        }
      break;
      case VTK_LONG:
        {
        long *scalars = static_cast<vtkLongArray *>(inScalars)->GetPointer(0);
        vtkMarchingCubesComputeGradient(this,scalars,dims,origin,Spacing,this->Locator,
                      newScalars,newGradients,
                      newNormals,newPolys,values,numContours);
        }
      break;
      case VTK_UNSIGNED_LONG:
        {
        unsigned long *scalars = static_cast<vtkUnsignedLongArray *>(inScalars)->GetPointer(0);
        vtkMarchingCubesComputeGradient(this,scalars,dims,origin,Spacing,this->Locator,
                      newScalars,newGradients,
                      newNormals,newPolys,values,numContours);
        }
      break;
      case VTK_FLOAT:
        {
        float *scalars = static_cast<vtkFloatArray *>(inScalars)->GetPointer(0);
        vtkMarchingCubesComputeGradient(this,scalars,dims,origin,Spacing,this->Locator,
                      newScalars,newGradients,
                      newNormals,newPolys,values,numContours);
        }
      break;
      case VTK_DOUBLE:
        {
        double *scalars = static_cast<vtkDoubleArray *>(inScalars)->GetPointer(0);
        vtkMarchingCubesComputeGradient(this,scalars,dims,origin,Spacing,this->Locator,
                      newScalars,newGradients,
                      newNormals,newPolys,values,numContours);
        }
      break;
      } //switch
    }

  else //multiple components - have to convert
    {
    int dataSize = dims[0] * dims[1] * dims[2];
    vtkFloatArray *image=vtkFloatArray::New(); 
    image->SetNumberOfComponents(inScalars->GetNumberOfComponents());
    image->SetNumberOfTuples(image->GetNumberOfComponents()*dataSize);
    inScalars->GetTuples(0,dataSize,image);

    float *scalars = image->GetPointer(0);
    vtkMarchingCubesComputeGradient(this,scalars,dims,origin,Spacing,this->Locator,
                  newScalars,newGradients,
                  newNormals,newPolys,values,numContours);
    image->Delete();
    }
  
  vtkDebugMacro(<<"Created: " 
               << newPts->GetNumberOfPoints() << " points, " 
               << newPolys->GetNumberOfCells() << " triangles");
  //
  // Update ourselves.  Because we don't know up front how many triangles
  // we've created, take care to reclaim memory. 
  //
  output->SetPoints(newPts);
  newPts->Delete();

  output->SetPolys(newPolys);
  newPolys->Delete();

  if (newScalars)
    {
    output->GetPointData()->SetScalars(newScalars);
    newScalars->Delete();
    }
  if (newGradients)
    {
    output->GetPointData()->SetVectors(newGradients);
    newGradients->Delete();
    }
  if (newNormals)
    {
    output->GetPointData()->SetNormals(newNormals);
    newNormals->Delete();
    }
  output->Squeeze();
  if (this->Locator)
    {
    this->Locator->Initialize(); //free storage
    }
}

// Description:
// Specify a spatial locator for merging points. By default, 
// an instance of vtkMergePoints is used.
void vtkMarchingCubes::SetLocator(vtkPointLocator *locator)
{
  if ( this->Locator == locator ) 
    {
    return;
    }
  
  if ( this->Locator )
    {
    this->Locator->UnRegister(this);
    this->Locator = NULL;
    }
  
  if (locator)
    {
    locator->Register(this);
    }
  
  this->Locator = locator;
  this->Modified();
}

void vtkMarchingCubes::CreateDefaultLocator()
{
  if ( this->Locator == NULL)
    {
    this->Locator = vtkMergePoints::New();
    }
}

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

  this->ContourValues->PrintSelf(os,indent);

  os << indent << "Compute Normals: " << (this->ComputeNormals ? "On\n" : "Off\n");
  os << indent << "Compute Gradients: " << (this->ComputeGradients ? "On\n" : "Off\n");
  os << indent << "Compute Scalars: " << (this->ComputeScalars ? "On\n" : "Off\n");

  if ( this->Locator )
    {
    os << indent << "Locator:" << this->Locator << "\n";
    this->Locator->PrintSelf(os,indent.GetNextIndent());
    }
  else
    {
    os << indent << "Locator: (none)\n";
    }
}
