vtkFlyingEdges3D.cxx 50.4 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkFlyingEdges3D.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 "vtkFlyingEdges3D.h"

#include "vtkMath.h"
#include "vtkImageData.h"
#include "vtkCellArray.h"
#include "vtkInformation.h"
#include "vtkInformationIntegerVectorKey.h"
#include "vtkInformationVector.h"
#include "vtkObjectFactory.h"
#include "vtkPointData.h"
#include "vtkPolyData.h"
#include "vtkFloatArray.h"
#include "vtkStreamingDemandDrivenPipeline.h"
#include "vtkMarchingCubesTriangleCases.h"
29
#include "vtkSMPTools.h"
30 31 32 33 34 35 36 37 38

#include <math.h>

vtkStandardNewMacro(vtkFlyingEdges3D);

//----------------------------------------------------------------------------

// This templated class implements the heart of the algorithm.
// vtkFlyingEdges3D populates the information in this class and
39
// then invokes Contour() to actually initiate execution.
40 41 42 43 44
template <class T>
class vtkFlyingEdges3DAlgorithm
{
public:
  // Edge case table values.
45 46 47 48 49 50 51
  enum {
    Below = 0, //below isovalue
    Above = 1, //above isovalue
    LeftAbove = 1, //left vertex is above isovalue
    RightAbove = 2, //right vertex is above isovalue
    BothAbove = 3 //entire edge is above isovalue
  };
52 53

  // Dealing with boundary situations when processing volumes.
54 55 56 57 58
  enum {
    Interior = 0,
    MinBoundary = 1,
    MaxBoundary = 2
  } vtkBoundarySituations;
59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100

  // Edge-based case table to generate output triangle primitives. It is
  // equivalent to the vertex-based Marching Cubes case table but provides
  // several computational advantages (parallel separability, more efficient
  // computation). This table is built from the MC case table when the class
  // is instantiated.
  unsigned char EdgeCases[256][16];

  // A table to map old edge ids (as defined from vtkMarchingCubesCases) into
  // the edge-based case table. This is so that the existing Marching Cubes
  // case tables can be reused.
  static const unsigned char EdgeMap[12];

  // A table that lists voxel point ids as a function of edge ids (edge ids
  // for edge-based case table).
  static const unsigned char VertMap[12][2];

  // A table describing vertex offsets (in index space) from the cube axes
  // origin for each of the eight vertices of a voxel.
  static const unsigned char VertOffsets[8][3];

  // This table is used to accelerate the generation of output triangles and
  // points. The EdgeUses array, a function of the voxel case number,
  // indicates which voxel edges intersect with the contour (i.e., require
  // interpolation). This array is filled in at instantiation during the case
  // table generation process.
  unsigned char EdgeUses[256][12];

  // Flags indicate whether a particular case requires voxel axes to be
  // processed. A cheap acceleration structure computed from the case
  // tables at the point of instantiation.
  unsigned char IncludesAxes[256];

  // Algorithm-derived data. XCases tracks the x-row edge cases. The
  // EdgeMetaData tracks information needed for parallel partitioning,
  // and to enable generation of the output primitives without using
  // a point locator.
  unsigned char *XCases;
  vtkIdType *EdgeMetaData;

  // Internal variables used by the various algorithm methods. Interfaces VTK
  // image data in a form more convenient to the algorithm.
Will Schroeder's avatar
Will Schroeder committed
101
  T        *Scalars;
102 103 104
  vtkIdType Dims[3];
  double   *Origin;
  double   *Spacing;
Will Schroeder's avatar
Will Schroeder committed
105
  vtkIdType NumberOfEdges;
106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128
  vtkIdType SliceOffset;
  int Min0;
  int Max0;
  int Inc0;
  int Min1;
  int Max1;
  int Inc1;
  int Min2;
  int Max2;
  int Inc2;

  // Output data. Threads write to partitioned memory.
  T         *NewScalars;
  vtkIdType *NewTris;
  float     *NewPoints;
  float     *NewGradients;
  float     *NewNormals;
  unsigned char NeedGradients;

  // Setup algorithm
  vtkFlyingEdges3DAlgorithm();

  // The three main passes of the algorithm.
Will Schroeder's avatar
Will Schroeder committed
129
  void ProcessXEdge(double value, T const * const inPtr, vtkIdType row, vtkIdType slice); //PASS 1
130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176
  void ProcessYZEdges(vtkIdType row, vtkIdType slice); //PASS 2
  void GenerateOutput(double value, T* inPtr, vtkIdType row, vtkIdType slice);//PASS 3

  // Place holder for now in case fancy bit fiddling is needed later.
  void SetXEdge(unsigned char *ePtr, unsigned char edgeCase)
    {*ePtr = edgeCase;}

  // Given the four x-edge cases defining this voxel, return the voxel case
  // number.
  unsigned char GetEdgeCase(unsigned char *ePtr[4])
    {
    return (*(ePtr[0]) | ((*(ePtr[1]))<<2) | ((*(ePtr[2]))<<4) | ((*(ePtr[3]))<<6));
    }

  // Return the number of contouring primitives for a particular edge case number.
  unsigned char GetNumberOfPrimitives(unsigned char eCase)
    { return this->EdgeCases[eCase][0]; }

  // Return an array indicating which voxel edges intersect the contour.
  unsigned char *GetEdgeUses(unsigned char eCase)
    { return this->EdgeUses[eCase]; }

  // Indicate whether voxel axes need processing for this case.
  unsigned char CaseIncludesAxes(unsigned char eCase)
    { return this->IncludesAxes[eCase]; }

  // Count edge intersections near volume boundaries.
  void CountBoundaryYZInts(unsigned char loc, unsigned char *edgeCases,
                           vtkIdType *eMD[4]);

  // Produce the output triangles for this voxel cell.
  void GenerateTris(unsigned char eCase, unsigned char numTris, vtkIdType *eIds,
                    vtkIdType &triId)
    {
      vtkIdType *tri;
      const unsigned char *edges = this->EdgeCases[eCase] + 1;
      for (int i=0; i < numTris; ++i, edges+=3)
        {
        tri = this->NewTris + 4*triId++;
        tri[0] = 3;
        tri[1] = eIds[edges[0]];
        tri[2] = eIds[edges[1]];
        tri[3] = eIds[edges[2]];
        }
    }

  // Compute gradient on interior point.
Will Schroeder's avatar
Will Schroeder committed
177 178 179 180 181
  void ComputeGradient(unsigned char loc, vtkIdType ijk[3],
                       T const * const s0_start, T const * const s0_end,
                       T const * const s1_start, T const * const s1_end,
                       T const * const s2_start, T const * const s2_end,
                       float g[3])
182 183 184
    {
      if ( loc == Interior )
        {
Will Schroeder's avatar
Will Schroeder committed
185 186 187
        g[0] = 0.5*( (*s0_start - *s0_end) / this->Spacing[0] );
        g[1] = 0.5*( (*s1_start - *s1_end) / this->Spacing[1] );
        g[2] = 0.5*( (*s2_start - *s2_end) / this->Spacing[2] );
188 189 190
        }
      else
        {
Will Schroeder's avatar
Will Schroeder committed
191 192 193 194 195
        this->ComputeBoundaryGradient(ijk,
                                      s0_start, s0_end,
                                      s1_start, s1_end,
                                      s2_start, s2_end,
                                      g);
196 197 198
        }
    }

Will Schroeder's avatar
Will Schroeder committed
199

200
  // Interpolate along a voxel axes edge.
Will Schroeder's avatar
Will Schroeder committed
201 202 203 204 205 206 207
  void InterpolateAxesEdge(double t, unsigned char loc,
                           float x0[3],
                           T const * const s,
                           const int incs[3],
                           float x1[3],
                           vtkIdType vId,
                           vtkIdType ijk[3],
208 209
                           float g0[3])
    {
Will Schroeder's avatar
Will Schroeder committed
210

211 212 213 214 215 216 217
      float *x = this->NewPoints + 3*vId;
      x[0] = x0[0] + t*(x1[0]-x0[0]);
      x[1] = x0[1] + t*(x1[1]-x0[1]);
      x[2] = x0[2] + t*(x1[2]-x0[2]);
      if ( this->NeedGradients )
        {
        float gTmp[3], g1[3];
Will Schroeder's avatar
Will Schroeder committed
218 219 220 221 222
        this->ComputeGradient(loc,ijk,
                              s + incs[0], s - incs[0],
                              s + incs[1], s - incs[1],
                              s + incs[2], s - incs[2],
                              g1);
223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240

        float *g = ( this->NewGradients ? this->NewGradients + 3*vId : gTmp );
        g[0] = g0[0] + t*(g1[0]-g0[0]);
        g[1] = g0[1] + t*(g1[1]-g0[1]);
        g[2] = g0[2] + t*(g1[2]-g0[2]);

        if ( this->NewNormals )
          {
          float *n = this->NewNormals + 3*vId;
          n[0] = -g[0];
          n[1] = -g[1];
          n[2] = -g[2];
          vtkMath::Normalize(n);
          }
        }//if normals or gradients required
    }

  // Compute the gradient on a point which may be on the boundary of the volume.
Will Schroeder's avatar
Will Schroeder committed
241 242 243 244 245
  void ComputeBoundaryGradient(vtkIdType ijk[3],
                               T const * const s0_start, T const * const s0_end,
                               T const * const s1_start, T const * const s1_end,
                               T const * const s2_start, T const * const s2_end,
                               float g[3]);
246 247 248 249

  // Interpolate along an arbitrary edge, typically one that may be on the
  // volume boundary. This means careful computation of stuff requiring
  // neighborhood information (e.g., gradients).
Will Schroeder's avatar
Will Schroeder committed
250 251 252 253 254
  void InterpolateEdge(double value, vtkIdType ijk[3],
                       T const * const s, const int incs[3],
                       float x[3],
                       unsigned char edgeNum,
                       unsigned char const* const edgeUses,
255 256 257
                       vtkIdType *eIds);

  // Produce the output points on the voxel axes for this voxel cell.
Will Schroeder's avatar
Will Schroeder committed
258 259 260 261
  void GeneratePoints(double value, unsigned char loc, vtkIdType ijk[3],
                      T const * const sPtr, const int incs[3],
                      float x[3], unsigned char const * const edgeUses,
                      vtkIdType *eIds);
262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298

  // Helper function to set up the point ids on voxel edges.
  unsigned char InitVoxelIds(unsigned char *ePtr[4], vtkIdType *eMD[4],
                             vtkIdType *eIds)
    {
      unsigned char eCase = GetEdgeCase(ePtr);
      eIds[0] = eMD[0][0]; //x-edges
      eIds[1] = eMD[1][0];
      eIds[2] = eMD[2][0];
      eIds[3] = eMD[3][0];
      eIds[4] = eMD[0][1]; //y-edges
      eIds[5] = eIds[4] + this->EdgeUses[eCase][4];
      eIds[6] = eMD[2][1];
      eIds[7] = eIds[6] + this->EdgeUses[eCase][6];
      eIds[8] = eMD[0][2]; //z-edges
      eIds[9] = eIds[8] + this->EdgeUses[eCase][8];
      eIds[10] = eMD[1][2];
      eIds[11] = eIds[10] + this->EdgeUses[eCase][10];
      return eCase;
    }

  // Helper function to advance the point ids along voxel rows.
  void AdvanceVoxelIds(unsigned char eCase, vtkIdType *eIds)
    {
      eIds[0] += this->EdgeUses[eCase][0]; //x-edges
      eIds[1] += this->EdgeUses[eCase][1];
      eIds[2] += this->EdgeUses[eCase][2];
      eIds[3] += this->EdgeUses[eCase][3];
      eIds[4] += this->EdgeUses[eCase][4]; //y-edges
      eIds[5] = eIds[4] + this->EdgeUses[eCase][5];
      eIds[6] += this->EdgeUses[eCase][6];
      eIds[7] = eIds[6] + this->EdgeUses[eCase][7];
      eIds[8] += this->EdgeUses[eCase][8]; //z-edges
      eIds[9] = eIds[8] + this->EdgeUses[eCase][9];
      eIds[10] += this->EdgeUses[eCase][10];
      eIds[11] = eIds[10] + this->EdgeUses[eCase][11];
    }
299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364

  // Threading integration via SMPTools
  template <class TT> class Pass1
    {
    public:
      vtkFlyingEdges3DAlgorithm<TT> *Algo;
      double Value;
      Pass1(vtkFlyingEdges3DAlgorithm<TT> *algo, double value)
        {this->Algo = algo; this->Value = value;}
      void  operator()(vtkIdType slice, vtkIdType end)
        {
        vtkIdType row;
        TT *rowPtr, *slicePtr = this->Algo->Scalars + slice*this->Algo->Inc2;
        for ( ; slice < end; ++slice )
          {
          for (row=0, rowPtr=slicePtr; row < this->Algo->Dims[1]; ++row)
            {
            this->Algo->ProcessXEdge(this->Value, rowPtr, row, slice);
            rowPtr += this->Algo->Inc1;
            }//for all rows in this slice
          slicePtr += this->Algo->Inc2;
          }//for all slices in this batch
        }
    };
  template <class TT> class Pass2
    {
    public:
      Pass2(vtkFlyingEdges3DAlgorithm<TT> *algo)
        {this->Algo = algo;}
      vtkFlyingEdges3DAlgorithm<TT> *Algo;
      void  operator()(vtkIdType slice, vtkIdType end)
        {
        for ( ; slice < end; ++slice)
          {
          for ( vtkIdType row=0; row < (this->Algo->Dims[1]-1); ++row)
            {
            this->Algo->ProcessYZEdges(row, slice);
            }//for all rows in this slice
          }//for all slices in this batch
        }
    };
  template <class TT> class Pass3
    {
    public:
      Pass3(vtkFlyingEdges3DAlgorithm<TT> *algo, double value)
        {this->Algo = algo; this->Value = value;}
      vtkFlyingEdges3DAlgorithm<TT> *Algo;
      double Value;
      void  operator()(vtkIdType slice, vtkIdType end)
        {
        vtkIdType row;
        vtkIdType *eMD0 = this->Algo->EdgeMetaData + slice*6*this->Algo->Dims[1];
        vtkIdType *eMD1 = eMD0 + 6*this->Algo->Dims[1];
        TT *rowPtr, *slicePtr = this->Algo->Scalars + slice*this->Algo->Inc2;
        for ( ; slice < end; ++slice )
          {
          // It's possible to skip entire slices if there is nothing to generate
          if ( eMD1[3] > eMD0[3] ) //there are triangle primitives!
            {
            for (row=0, rowPtr=slicePtr; row < this->Algo->Dims[1]-1; ++row)
              {
              this->Algo->GenerateOutput(this->Value, rowPtr, row, slice);
              rowPtr += this->Algo->Inc1;
              }//for all rows in this slice
            }//if there are triangles
          slicePtr += this->Algo->Inc2;
365 366
          eMD0 = eMD1;
          eMD1 = eMD0 + 6*this->Algo->Dims[1];
367 368 369 370 371 372 373 374 375 376
          }//for all slices in this batch
        }
    };

  // Interface between VTK and templated functions
  static void Contour(vtkFlyingEdges3D *self, vtkImageData *input,
                      int extent[6], vtkIdType *incs, T *scalars,
                      vtkPoints *newPts, vtkCellArray *newTris,
                      vtkDataArray *newScalars,vtkFloatArray *newNormals,
                      vtkFloatArray *newGradients);
377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402
};

//----------------------------------------------------------------------------
// Map MC edges numbering to use the saner FlyingEdges edge numbering scheme.
template <class T> const unsigned char vtkFlyingEdges3DAlgorithm<T>::
EdgeMap[12] = {0,5,1,4,2,7,3,6,8,9,10,11};

//----------------------------------------------------------------------------
// Map MC edges numbering to use the saner FlyingEdges edge numbering scheme.
template <class T> const unsigned char vtkFlyingEdges3DAlgorithm<T>::
VertMap[12][2] = {{0,1}, {2,3}, {4,5}, {6,7}, {0,2}, {1,3}, {4,6}, {5,7},
                  {0,4}, {1,5}, {2,6}, {3,7}};

//----------------------------------------------------------------------------
// The offsets of each vertex (in index space) from the voxel axes origin.
template <class T> const unsigned char vtkFlyingEdges3DAlgorithm<T>::
VertOffsets[8][3] = {{0,0,0}, {1,0,0}, {0,1,0}, {1,1,0},
                     {0,0,1}, {1,0,1}, {0,1,1}, {1,1,1}};

//----------------------------------------------------------------------------
// Instantiate and initialize key data members. Mostly we build the
// edge-based case table, and associated acceleration structures, from the
// marching cubes case table. Some of this code is borrowed shamelessly from
// vtkVoxel::Contour() method.
template <class T> vtkFlyingEdges3DAlgorithm<T>::
vtkFlyingEdges3DAlgorithm():XCases(NULL),EdgeMetaData(NULL),NewScalars(NULL),
Will Schroeder's avatar
Will Schroeder committed
403
                            NewTris(NULL),NewPoints(NULL),NewGradients(NULL),
404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460
                            NewNormals(NULL)
{
  int i, j, k, l, ii, eCase, index, numTris;
  static int vertMap[8] = {0,1,3,2,4,5,7,6};
  static int CASE_MASK[8] = {1,2,4,8,16,32,64,128};
  EDGE_LIST *edge;
  vtkMarchingCubesTriangleCases *triCase;
  unsigned char *edgeCase;

  // Initialize cases, increments, and edge intersection flags
  for (eCase=0; eCase<256; ++eCase)
    {
    for (j=0; j<16; ++j)
      {
      this->EdgeCases[eCase][j] = 0;
      }
    for (j=0; j<12; ++j)
      {
      this->EdgeUses[eCase][j] = 0;
      }
    this->IncludesAxes[eCase] = 0;
    }

  // The voxel, edge-based case table is a function of the four x-edge cases
  // that define the voxel. Here we convert the existing MC vertex-based case
  // table into a x-edge case table. Note that the four x-edges are ordered
  // (0->3): x, x+y, x+z, x+y+z; the four y-edges are ordered (4->7): y, y+x,
  // y+z, y+x+z; and the four z-edges are ordered (8->11): z, z+x, z+y,
  // z+x+y.
  for (l=0; l<4; ++l)
    {
    for (k=0; k<4; ++k)
      {
      for (j=0; j<4; ++j)
        {
        for (i=0; i<4; ++i)
          {
          //yes we could just count to (0->255) but where's the fun in that?
          eCase = i | (j<<2) | (k<<4) | (l<<6);
          for ( ii=0, index = 0; ii < 8; ++ii)
            {
            if ( eCase & (1<<vertMap[ii]) ) //map into ancient MC table
              {
              index |= CASE_MASK[ii];
              }
            }
          //Now build case table
          triCase = vtkMarchingCubesTriangleCases::GetCases() + index;
          edge = triCase->edges;
          for ( numTris=0, edge=triCase->edges; edge[0] > -1; edge += 3 )
            {//count the number of triangles
            numTris++;
            }
          if ( numTris > 0 )
            {
            edgeCase = this->EdgeCases[eCase];
            *edgeCase++ = numTris;
461 462 463 464 465 466 467 468 469 470
            for ( edge = triCase->edges; edge[0] > -1; edge += 3, edgeCase+=3 )
              {
              // Build new case table. You're probably wondering why the
              // crazy (0,2,1) edge order below. Simple: as originally
              // presented the MC algorithm used a left-handed coordinate
              // system, so we have to reverse the ordering of the triangle
              // to make it consistent with any generated normals.
              edgeCase[0] = this->EdgeMap[edge[0]];
              edgeCase[2] = this->EdgeMap[edge[1]];
              edgeCase[1] = this->EdgeMap[edge[2]];
471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552
              }
            }
          }//x-edges
        }//x+y-edges
      }//x+z-edges
    }//x+y+z-edges

  // Okay now build the acceleration structure. This is used to generate
  // output points and triangles when processing a voxel x-row as well as to
  // perform other topological reasoning. This structure is a function of the
  // particular case number.
  for (eCase=0; eCase < 256; ++eCase)
    {
    edgeCase = this->EdgeCases[eCase];
    numTris = *edgeCase++;

    // Mark edges that are used by this case.
    for (i=0; i < numTris*3; ++i) //just loop over all edges
      {
      this->EdgeUses[eCase][edgeCase[i]] = 1;
      }

    this->IncludesAxes[eCase] = this->EdgeUses[eCase][0] |
      this->EdgeUses[eCase][4] | this->EdgeUses[eCase][8];

    }//for all cases
}

//----------------------------------------------------------------------------
// Count intersections along voxel axes. When traversing the volume across
// x-edges, the voxel axes on the boundary may be undefined near boundaries
// (because there are no fully-formed cells). Thus the voxel axes on the
// boundary are treated specially.
template <class T> void vtkFlyingEdges3DAlgorithm<T>::
CountBoundaryYZInts(unsigned char loc, unsigned char *edgeUses,
                    vtkIdType *eMD[4])
{
  switch (loc)
    {
    case 2: //+x boundary
      eMD[0][1] += edgeUses[5];
      eMD[0][2] += edgeUses[9];
      break;
    case 8: //+y
      eMD[1][2] += edgeUses[10];
      break;
    case 10://+x +y
      eMD[0][1] += edgeUses[5];
      eMD[0][2] += edgeUses[9];
      eMD[1][2] += edgeUses[10];
      eMD[1][2] += edgeUses[11];
      break;
    case 32://+z
      eMD[2][1] += edgeUses[6];
      break;
    case 34: //+x +z
      eMD[0][1] += edgeUses[5];
      eMD[0][2] += edgeUses[9];
      eMD[2][1] += edgeUses[6];
      eMD[2][1] += edgeUses[7];
      break;
    case 40: //+y +z
      eMD[2][1] += edgeUses[6];
      eMD[1][2] += edgeUses[10];
      break;
    case 42: //+x +y +z happens no more than once per volume
      eMD[0][1] += edgeUses[5];
      eMD[0][2] += edgeUses[9];
      eMD[1][2] += edgeUses[10];
      eMD[1][2] += edgeUses[11];
      eMD[2][1] += edgeUses[6];
      eMD[2][1] += edgeUses[7];
      break;
    default: //uh-oh shouldn't happen
      break;
    }
}

//----------------------------------------------------------------------------
// Compute the gradient when the point may be near the boundary of the
// volume.
template <class T> void vtkFlyingEdges3DAlgorithm<T>::
Will Schroeder's avatar
Will Schroeder committed
553 554 555 556 557
ComputeBoundaryGradient(vtkIdType ijk[3],
                        T const * const s0_start, T const * const s0_end,
                        T const * const s1_start, T const * const s1_end,
                        T const * const s2_start, T const * const s2_end,
                        float g[3])
558
{
Will Schroeder's avatar
Will Schroeder committed
559 560
  const T* s = s0_start - this->Inc0;

561 562
  if ( ijk[0] == 0 )
    {
Will Schroeder's avatar
Will Schroeder committed
563
    g[0] = (*s0_start - *s) / this->Spacing[0];
564 565 566
    }
  else if ( ijk[0] >= (this->Dims[0]-1) )
    {
Will Schroeder's avatar
Will Schroeder committed
567
    g[0] = (*s - *s0_end) / this->Spacing[0];
568 569 570
    }
  else
    {
Will Schroeder's avatar
Will Schroeder committed
571
    g[0] = 0.5 * ( (*s0_start - *s0_end) / this->Spacing[0] );
572 573 574 575
    }

  if ( ijk[1] == 0 )
    {
Will Schroeder's avatar
Will Schroeder committed
576
    g[1] = (*s1_start - *s) / this->Spacing[1];
577 578 579
    }
  else if ( ijk[1] >= (this->Dims[1]-1) )
    {
Will Schroeder's avatar
Will Schroeder committed
580
    g[1] = (*s - *s1_end) / this->Spacing[1];
581 582 583
    }
  else
    {
Will Schroeder's avatar
Will Schroeder committed
584
    g[1] = 0.5 * ( (*s1_start - *s1_end) / this->Spacing[1] );
585 586 587 588
    }

  if ( ijk[2] == 0 )
    {
Will Schroeder's avatar
Will Schroeder committed
589
    g[2] = (*s2_start - *s) / this->Spacing[2];
590 591 592
    }
  else if ( ijk[2] >= (this->Dims[2]-1) )
    {
Will Schroeder's avatar
Will Schroeder committed
593
    g[2] = (*s - *s2_end) / this->Spacing[2];
594 595 596
    }
  else
    {
Will Schroeder's avatar
Will Schroeder committed
597
    g[2] = 0.5 * ( (*s2_start - *s2_end) / this->Spacing[2] );
598 599 600 601 602
    }
}

//----------------------------------------------------------------------------
// Interpolate a new point along a boundary edge. Make sure to consider
603
// proximity to the boundary when computing gradients, etc.
604
template <class T> void vtkFlyingEdges3DAlgorithm<T>::
Will Schroeder's avatar
Will Schroeder committed
605 606 607 608 609 610
InterpolateEdge(double value, vtkIdType ijk[3],
                T const * const s,
                const int incs[3],
                float x[3],
                unsigned char edgeNum,
                unsigned char const * const edgeUses,
611 612 613 614 615 616 617 618 619 620
                vtkIdType *eIds)
{
  // if this edge is not used then get out
  if ( ! edgeUses[edgeNum] )
    {
    return;
    }

  // build the edge information
  const unsigned char *vertMap = this->VertMap[edgeNum];
Will Schroeder's avatar
Will Schroeder committed
621

622 623 624 625 626
  float x0[3], x1[3];
  vtkIdType ijk0[3], ijk1[3], vId=eIds[edgeNum];
  int i;

  const unsigned char *offsets = this->VertOffsets[vertMap[0]];
Will Schroeder's avatar
Will Schroeder committed
627 628 629
  T const * const s0 = s + offsets[0]*incs[0] +
                           offsets[1]*incs[1] +
                           offsets[2]*incs[2];
630 631 632 633 634 635 636
  for (i=0; i<3; ++i)
    {
    ijk0[i] = ijk[i] + offsets[i];
    x0[i] = x[i] + offsets[i]*this->Spacing[i];
    }

  offsets = this->VertOffsets[vertMap[1]];
Will Schroeder's avatar
Will Schroeder committed
637 638 639
  T const * const s1 = s + offsets[0]*incs[0] +
                           offsets[1]*incs[1] +
                           offsets[2]*incs[2];
640 641 642 643 644 645 646 647 648 649 650 651 652 653 654
  for (i=0; i<3; ++i)
    {
    ijk1[i] = ijk[i] + offsets[i];
    x1[i] = x[i] + offsets[i]*this->Spacing[i];
    }

  // Okay interpolate
  double t = (value - *s0) / (*s1 - *s0);
  float *xPtr = this->NewPoints + 3*vId;
  xPtr[0] = x0[0] + t*(x1[0]-x0[0]);
  xPtr[1] = x0[1] + t*(x1[1]-x0[1]);
  xPtr[2] = x0[2] + t*(x1[2]-x0[2]);
  if ( this->NeedGradients )
    {
    float gTmp[3], g0[3], g1[3];
Will Schroeder's avatar
Will Schroeder committed
655 656 657 658 659 660 661 662 663 664
    this->ComputeBoundaryGradient(ijk0,
                                  s0+incs[0], s0-incs[0],
                                  s0+incs[1], s0-incs[1],
                                  s0+incs[2], s0-incs[2],
                                  g0);
    this->ComputeBoundaryGradient(ijk1,
                                  s1+incs[0], s1-incs[0],
                                  s1+incs[1], s1-incs[1],
                                  s1+incs[2], s1-incs[2],
                                  g1);
665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685

    float *g = ( this->NewGradients ? this->NewGradients + 3*vId : gTmp );
    g[0] = g0[0] + t*(g1[0]-g0[0]);
    g[1] = g0[1] + t*(g1[1]-g0[1]);
    g[2] = g0[2] + t*(g1[2]-g0[2]);

    if ( this->NewNormals )
      {
      float *n = this->NewNormals + 3*vId;
      n[0] = -g[0];
      n[1] = -g[1];
      n[2] = -g[2];
      vtkMath::Normalize(n);
      }
    }//if normals or gradients required
}

//----------------------------------------------------------------------------
// Generate the output points and optionally normals, gradients and
// interpolate attributes.
template <class T> void vtkFlyingEdges3DAlgorithm<T>::
Will Schroeder's avatar
Will Schroeder committed
686 687 688 689 690
GeneratePoints(double value, unsigned char loc, vtkIdType ijk[3],
               T const * const sPtr, const int incs[3],
               float x[3],
               unsigned char const * const edgeUses,
               vtkIdType *eIds)
691 692
{
  // Create a slightly faster path for voxel axes interior to the volume.
Will Schroeder's avatar
Will Schroeder committed
693
  float g0[3];
694 695
  if ( this->NeedGradients )
    {
Will Schroeder's avatar
Will Schroeder committed
696 697 698 699 700
    this->ComputeGradient(loc,ijk,
                          sPtr + incs[0], sPtr - incs[0],
                          sPtr + incs[1], sPtr - incs[1],
                          sPtr + incs[2], sPtr - incs[2],
                          g0);
701
    }
Will Schroeder's avatar
Will Schroeder committed
702 703

  for(int i=0; i < 3; ++i)
704
    {
Will Schroeder's avatar
Will Schroeder committed
705 706 707 708 709 710 711 712 713 714 715 716
    if(edgeUses[i*4])
      {
      //edgesUses[0] == x axes edge
      //edgesUses[4] == y axes edge
      //edgesUses[8] == z axes edge
      float x1[3] = {x[0], x[1], x[2] }; x1[i] += this->Spacing[i];
      vtkIdType ijk1[3] = { ijk[0], ijk[1], ijk[2] }; ++ijk[i];

      T const * const sPtr2 = (sPtr+incs[i]);
      double t = (value - *sPtr) / (*sPtr2 - *sPtr);
      this->InterpolateAxesEdge(t, loc, x, sPtr2, incs, x1, eIds[i*4], ijk1, g0);
      }
717 718 719 720 721 722 723 724 725 726
    }

  // Otherwise do more general gyrations. These are boundary situations where
  // the voxel axes is not fully formed. These situations occur on the
  // +x,+y,+z volume boundaries. (The other cases are handled by the default:
  // case and are expected.)
  switch (loc) //location is one of 27 regions in the volume
    {
    case 2: case 6: case 18:
    case 22: case 26: //+x & +x -y & +x -z & +x -y -z +x +y -z
Will Schroeder's avatar
Will Schroeder committed
727 728
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 5, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 9, edgeUses, eIds);
729 730
      break;
    case 8: case 24: case 25: //+y & +y -z & +y -x -z
Will Schroeder's avatar
Will Schroeder committed
731 732
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 1, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 10, edgeUses, eIds);
733 734
      break;
    case 10://+x +y
Will Schroeder's avatar
Will Schroeder committed
735 736 737 738 739
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 1, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 5, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 9, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 10, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 11, edgeUses, eIds);
740 741
      break;
    case 32: case 33: case 36: case 37: //+z & -x +z & -y +z & -x -y +z
Will Schroeder's avatar
Will Schroeder committed
742 743
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 2, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 6, edgeUses, eIds);
744 745
      break;
    case 34: case 38: //+x +z & +x -y +z
Will Schroeder's avatar
Will Schroeder committed
746 747 748 749 750
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 2, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 5, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 9, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 6, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 7, edgeUses, eIds);
751 752
      break;
    case 9: case 40: case 41: //-x +y & +y +z & -x + y + z
Will Schroeder's avatar
Will Schroeder committed
753 754 755 756 757
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 1, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 2, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 3, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 6, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 10, edgeUses, eIds);
758 759
      break;
    case 42: //+x +y +z happens no more than once per volume
Will Schroeder's avatar
Will Schroeder committed
760 761 762 763 764 765 766 767 768
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 1, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 2, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 3, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 5, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 9, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 10, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 11, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 6, edgeUses, eIds);
      this->InterpolateEdge(value, ijk, sPtr, incs, x, 7, edgeUses, eIds);
769 770 771 772 773 774 775 776 777 778 779 780 781
      break;
    default: //interior, or -x,-y,-z boundary
      return;
    }
}

//----------------------------------------------------------------------------
// PASS 1: Process a single volume x-row (and all of the voxel edges that
// compose the row). Determine the x-edges case classification, count the
// number of x-edge intersections, and figure out where intersections along
// the x-row begins and ends (i.e., gather information for computational
// trimming).
template <class T> void vtkFlyingEdges3DAlgorithm<T>::
Will Schroeder's avatar
Will Schroeder committed
782
ProcessXEdge(double value, T const* const inPtr, vtkIdType row, vtkIdType slice)
783 784 785 786 787 788 789 790 791 792
{
  vtkIdType nxcells=this->Dims[0]-1;
  vtkIdType minInt=nxcells, maxInt = 0;
  vtkIdType *edgeMetaData;
  unsigned char *ePtr = this->XCases + slice*this->SliceOffset + row*nxcells;
  double s0, s1 = static_cast<double>(*inPtr);

  //run along the entire x-edge computing edge cases
  edgeMetaData = this->EdgeMetaData + (slice*this->Dims[1] + row)*6;
  std::fill_n(edgeMetaData, 6, 0);
Will Schroeder's avatar
Will Schroeder committed
793 794 795 796 797 798

  vtkIdType sum = 0;

  //pull this out help reduce false sharing
  vtkIdType inc0 = this->Inc0;

799 800 801
  for (vtkIdType i=0; i < nxcells; ++i, ++ePtr)
    {
    s0 = s1;
Will Schroeder's avatar
Will Schroeder committed
802
    s1 = static_cast<double>(*(inPtr + (i+1)*inc0));
803

Will Schroeder's avatar
Will Schroeder committed
804 805 806 807 808 809 810 811 812
    unsigned char edgeCase = vtkFlyingEdges3DAlgorithm::Below;
    if (s0 >= value)
      {
      edgeCase = vtkFlyingEdges3DAlgorithm::LeftAbove;
      }
    if( s1 >= value)
      {
      edgeCase |= vtkFlyingEdges3DAlgorithm::RightAbove;
      }
813 814 815 816 817 818 819

    this->SetXEdge(ePtr, edgeCase);

    // if edge intersects contour
    if ( edgeCase == vtkFlyingEdges3DAlgorithm::LeftAbove ||
         edgeCase == vtkFlyingEdges3DAlgorithm::RightAbove )
      {
Will Schroeder's avatar
Will Schroeder committed
820
      ++sum; //increment number of intersections along x-edge
821 822 823 824 825
      minInt = ( i < minInt ? i : minInt);
      maxInt = i + 1;
      }//if contour interacts with this x-edge
    }//for all x-cell edges along this x-edge

Will Schroeder's avatar
Will Schroeder committed
826 827
  edgeMetaData[0] += sum; //write back the number of intersections along x-edge

828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991
  // The beginning and ending of intersections along the edge is used for
  // computational trimming.
  edgeMetaData[4] = minInt; //where intersections start along x edge
  edgeMetaData[5] = maxInt; //where intersections end along x edge
}

//----------------------------------------------------------------------------
// PASS 2: Process a single x-row of voxels. Count the number of y- and
// z-intersections by topological reasoning from x-edge cases. Determine the
// number of primitives (i.e., triangles) generated from this row. Use
// computational trimming to reduce work. Note *ePtr[4] is four pointers to
// four x-edge rows that bound the voxel x-row and which contain edge case
// information.
template <class T> void vtkFlyingEdges3DAlgorithm<T>::
ProcessYZEdges(vtkIdType row, vtkIdType slice)
{
  // Grab the four edge cases bounding this voxel x-row.
  unsigned char *ePtr[4], ec0, ec1, ec2, ec3;
  ePtr[0] = this->XCases + slice*this->SliceOffset + row*(this->Dims[0]-1);
  ePtr[1] = ePtr[0] + this->Dims[0]-1;
  ePtr[2] = ePtr[0] + this->SliceOffset;
  ePtr[3] = ePtr[2] + this->Dims[0]-1;

  // Grab the edge meta data surrounding the voxel row.
  vtkIdType *eMD[4];
  eMD[0] = this->EdgeMetaData + (slice*this->Dims[1] + row)*6; //this x-edge
  eMD[1] = eMD[0] + 6; //x-edge in +y direction
  eMD[2] = eMD[0] + this->Dims[1]*6; //x-edge in +z direction
  eMD[3] = eMD[2] + 6; //x-edge in +y+z direction

  // Determine whether this row of x-cells needs processing. If there are no
  // x-edge intersections, and the state of the four bounding x-edges is the
  // same, then there is no need for processing.
  if ( (eMD[0][0] | eMD[1][0] | eMD[2][0] | eMD[3][0]) == 0 ) //any x-ints?
    {
    if ( *(ePtr[0]) == *(ePtr[1]) &&  *(ePtr[1]) == *(ePtr[2]) &&
         *(ePtr[2]) == *(ePtr[3]) )
      {
      return; //there are no y- or z-ints, thus no contour, skip voxel row
      }
    }

  // Determine proximity to the boundary of volume. This information is used
  // to count edge intersections in boundary situations.
  unsigned char loc, yLoc, zLoc, yzLoc;
  yLoc = (row >= (this->Dims[1]-2) ? MaxBoundary : Interior);
  zLoc = (slice >= (this->Dims[2]-2) ? MaxBoundary : Interior);
  yzLoc = (yLoc << 2) | (zLoc << 4);

  // The trim edges may need adjustment if the contour travels between rows
  // of x-edges (without intersecting these x-edges). This means checking
  // whether the trim faces at (xL,xR) made up of the y-z edges intersect the
  // contour. Basically just an intersection operation. Determine the voxel
  // row trim edges, need to check all four x-edges.
  vtkIdType xL=eMD[0][4], xR=eMD[0][5];
  vtkIdType i;
  for (i=1; i < 4; ++i)
    {
    xL = ( eMD[i][4] < xL ? eMD[i][4] : xL);
    xR = ( eMD[i][5] > xR ? eMD[i][5] : xR);
    }

  if ( xL > 0 ) //if trimmed in the -x direction
    {
    ec0 = *(ePtr[0]+xL); ec1 = *(ePtr[1]+xL);
    ec2 = *(ePtr[2]+xL); ec3 = *(ePtr[3]+xL);
    if ( (ec0 & 0x1) != (ec1 & 0x1) || (ec1 & 0x1) != (ec2 & 0x1) ||
         (ec2 & 0x1) != (ec3 & 0x1) )
      {
      xL = eMD[0][4] = 0; //reset left trim
      }
    }

  if ( xR < (this->Dims[0]-1) ) //if trimmed in the +x direction
    {
    ec0 = *(ePtr[0]+xR); ec1 = *(ePtr[1]+xR);
    ec2 = *(ePtr[2]+xR); ec3 = *(ePtr[3]+xR);
    if ( (ec0 & 0x2) != (ec1 & 0x2) || (ec1 & 0x2) != (ec2 & 0x2) ||
         (ec2 & 0x2) != (ec3 & 0x2) )
      {
      xR = eMD[0][5] = this->Dims[0]-1; //reset right trim
      }
    }

  // Okay run along the x-voxels and count the number of y- and
  // z-intersections. Here we are just checking y,z edges that make up the
  // voxel axes. Also check the number of primitives generated.
  unsigned char *edgeUses, eCase, numTris;
  ePtr[0] += xL; ePtr[1] += xL; ePtr[2] += xL; ePtr[3] += xL;
  for (i=xL; i < xR; ++i) //run along the trimmed x-voxels
    {
    eCase = this->GetEdgeCase(ePtr);
    if ( (numTris=this->GetNumberOfPrimitives(eCase)) > 0 )
      {
      // Okay let's increment the triangle count.
      eMD[0][3] += numTris;

      // Count the number of y- and z-points to be generated. Pass# 1 counted
      // the number of x-intersections along the x-edges. Now we count all
      // intersections on the y- and z-voxel axes.
      edgeUses = this->GetEdgeUses(eCase);
      eMD[0][1] += edgeUses[4]; //y-voxel axes edge always counted
      eMD[0][2] += edgeUses[8]; //z-voxel axes edge always counted
      loc = yzLoc | (i >= (this->Dims[0]-2) ? MaxBoundary : Interior);
      if ( loc != 0 )
        {
        this->CountBoundaryYZInts(loc,edgeUses,eMD);
        }
      }//if cell contains contour

    // advance the four pointers along voxel row
    ePtr[0]++; ePtr[1]++; ePtr[2]++; ePtr[3]++;
    }//for all voxels along this x-edge
}

//----------------------------------------------------------------------------
// PASS 3: Process the x-row cells to generate output primitives, including
// point coordinates and triangles. This is the third pass of the algorithm.
template <class T> void vtkFlyingEdges3DAlgorithm<T>::
GenerateOutput(double value, T* rowPtr, vtkIdType row, vtkIdType slice)
{
  // Grab the edge meta data surrounding the voxel row.
  vtkIdType *eMD[4];
  eMD[0] = this->EdgeMetaData + (slice*this->Dims[1] + row)*6; //this x-edge
  eMD[1] = eMD[0] + 6; //x-edge in +y direction
  eMD[2] = eMD[0] + this->Dims[1]*6; //x-edge in +z direction
  eMD[3] = eMD[2] + 6; //x-edge in +y+z direction

  // Return if there is nothing to do (i.e., no triangles to generate)
  if ( eMD[0][3] == eMD[1][3] )
    {
    return;
    }

  // Get the voxel row trim edges and prepare to generate. Find the voxel row
  // trim edges, need to check all four x-edges to compute row trim edge.
  vtkIdType xL=eMD[0][4], xR=eMD[0][5];
  vtkIdType i;
  for (i=1; i < 4; ++i)
    {
    xL = ( eMD[i][4] < xL ? eMD[i][4] : xL);
    xR = ( eMD[i][5] > xR ? eMD[i][5] : xR);
    }

  // Grab the four edge cases bounding this voxel x-row. Begin at left trim edge.
  unsigned char *ePtr[4];
  ePtr[0] = this->XCases + slice*this->SliceOffset + row*(this->Dims[0]-1) + xL;
  ePtr[1] = ePtr[0] + this->Dims[0]-1;
  ePtr[2] = ePtr[0] + this->SliceOffset;
  ePtr[3] = ePtr[2] + this->Dims[0]-1;

  // Update scalars along this x-row if necessary
  vtkIdType numNewPts = eMD[1][0] - eMD[0][0];
  if ( this->NewScalars && numNewPts > 0 )
    {
    T TValue = static_cast<T>(value);
    std::fill_n(this->NewScalars+eMD[0][0], numNewPts, TValue);
    }

  // Traverse all voxels in this row, those containing the contour are
  // further identified for processing, meaning generating points and
  // triangles. Begin by setting up point ids on voxel edges.
  vtkIdType triId = eMD[0][3];
  vtkIdType eIds[12]; //the ids of generated points
Will Schroeder's avatar
Will Schroeder committed
992

993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007
  unsigned char eCase = this->InitVoxelIds(ePtr,eMD,eIds);

  // Determine the proximity to the boundary of volume. This information is
  // used to generate edge intersections.
  unsigned char loc, yLoc, zLoc, yzLoc;
  yLoc = (row < 1 ? MinBoundary :
          (row >= (this->Dims[1]-2) ? MaxBoundary : Interior));
  zLoc = (slice < 1 ? MinBoundary :
          (slice >= (this->Dims[2]-2) ? MaxBoundary : Interior));
  yzLoc = (yLoc << 2) | (zLoc << 4);

  // Run along voxels in x-row direction and generate output primitives. Note
  // that active voxel axes edges are interpolated to produce points and
  // possibly interpolate attribute data.
  float x[3];
Will Schroeder's avatar
Will Schroeder committed
1008
  x[0] = this->Origin[0] + xL*this->Spacing[0];
1009 1010
  x[1] = this->Origin[1] + row*this->Spacing[1];
  x[2] = this->Origin[2] + slice*this->Spacing[2];
Will Schroeder's avatar
Will Schroeder committed
1011 1012 1013 1014 1015 1016 1017 1018

  //compute the ijk for this section
  vtkIdType ijk[3] = { xL, row, slice};

  //load the inc0/inc1/inc2 into local memory
  const int incs[3] = { this->Inc0, this->Inc1, this->Inc2 };
  const T* sPtr = rowPtr + xL*incs[0];

1019 1020
  for (i=xL; i < xR; ++i)
    {
Will Schroeder's avatar
Will Schroeder committed
1021 1022
    const unsigned char numTris = this->GetNumberOfPrimitives(eCase);
    if ( numTris > 0 )
1023 1024 1025 1026 1027 1028 1029 1030 1031 1032
      {
      // Start by generating triangles for this case
      this->GenerateTris(eCase,numTris,eIds,triId);

      // Now generate point(s) along voxel axes if needed. Remember to take
      // boundary into account.
      loc = yzLoc | (i < 1 ? MinBoundary :
          (i >= (this->Dims[0]-2) ? MaxBoundary : Interior));
      if ( this->CaseIncludesAxes(eCase) || loc != Interior )
        {
Will Schroeder's avatar
Will Schroeder committed
1033 1034 1035 1036
        unsigned char const * const edgeUses = this->GetEdgeUses(eCase);
        this->GeneratePoints(value, loc, ijk,
                             sPtr, incs,
                             x, edgeUses, eIds);
1037 1038 1039 1040 1041 1042
        }
      this->AdvanceVoxelIds(eCase,eIds);
      }

    // advance along voxel row
    ePtr[0]++; ePtr[1]++; ePtr[2]++; ePtr[3]++;
Will Schroeder's avatar
Will Schroeder committed
1043 1044 1045 1046 1047
    eCase = this->GetEdgeCase(ePtr);

    ++ijk[0];
    sPtr += incs[0];
    x[0]+= this->Spacing[0];
1048 1049 1050 1051 1052 1053 1054
    } //for all non-trimmed cells along this x-edge
}

//----------------------------------------------------------------------------
// Contouring filter specialized for 3D volumes. This templated function
// interfaces the vtkFlyingEdges3D class with the templated algorithm
// class. It also invokes the three passes of the Flying Edges algorithm.
1055 1056 1057 1058 1059
template <class T> void vtkFlyingEdges3DAlgorithm<T>::
Contour(vtkFlyingEdges3D *self, vtkImageData *input, int extent[6],
        vtkIdType *incs, T *scalars, vtkPoints *newPts, vtkCellArray *newTris,
        vtkDataArray *newScalars, vtkFloatArray *newNormals,
        vtkFloatArray *newGradients)
1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071
{
  double value, *values = self->GetValues();
  int numContours = self->GetNumberOfContours();
  vtkIdType vidx, row, slice, *eMD, zInc;
  vtkIdType numOutXPts, numOutYPts, numOutZPts, numOutTris;
  vtkIdType numXPts=0, numYPts=0, numZPts=0, numTris=0;
  vtkIdType startXPts, startYPts, startZPts, startTris;
  startXPts = startYPts = startZPts = startTris = 0;

  // This may be subvolume of the total 3D image. Capture information for
  // subsequent processing.
  vtkFlyingEdges3DAlgorithm<T> algo;
Will Schroeder's avatar
Will Schroeder committed
1072
  algo.Scalars = scalars;
1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088
  algo.Origin = input->GetOrigin();
  algo.Spacing = input->GetSpacing();
  algo.Min0 = extent[0];
  algo.Max0 = extent[1];
  algo.Inc0 = incs[0];
  algo.Min1 = extent[2];
  algo.Max1 = extent[3];
  algo.Inc1 = incs[1];
  algo.Min2 = extent[4];
  algo.Max2 = extent[5];
  algo.Inc2 = incs[2];

  // Now allocate working arrays. The XCases array tracks x-edge cases.
  algo.Dims[0] = algo.Max0 - algo.Min0 + 1;
  algo.Dims[1] = algo.Max1 - algo.Min1 + 1;
  algo.Dims[2] = algo.Max2 - algo.Min2 + 1;
Will Schroeder's avatar
Will Schroeder committed
1089
  algo.NumberOfEdges = algo.Dims[1]*algo.Dims[2];
1090
  algo.SliceOffset = (algo.Dims[0]-1) * algo.Dims[1];
Will Schroeder's avatar
Will Schroeder committed
1091
  algo.XCases = new unsigned char [(algo.Dims[0]-1)*algo.NumberOfEdges];
1092 1093 1094 1095 1096 1097 1098

  // Also allocate the characterization (metadata) array for the x edges.
  // This array tracks the number of x-, y- and z- intersections on the voxel
  // axes along an x-edge; as well as the number of the output triangles, and
  // the xMin_i and xMax_i (minimum index of first intersection, maximum
  // index of intersection for the ith x-row, the so-called trim edges used
  // for computational trimming).
Will Schroeder's avatar
Will Schroeder committed
1099
  algo.EdgeMetaData = new vtkIdType [algo.NumberOfEdges*6];
1100 1101 1102 1103 1104 1105 1106 1107 1108 1109

  // Loop across each contour value. This encompasses all three passes.
  for (vidx = 0; vidx < numContours; vidx++)
    {
    value = values[vidx];

    // PASS 1: Traverse all x-rows building edge cases and counting number of
    // intersections (i.e., accumulate information necessary for later output
    // memory allocation, e.g., the number of output points along the x-rows
    // are counted).
1110
    Pass1<T> pass1(&algo,value);
1111
    vtkSMPTools::For(0,algo.Dims[2], pass1);
1112 1113 1114 1115

    // PASS 2: Traverse all voxel x-rows and process voxel y&z edges.  The
    // result is a count of the number of y- and z-intersections, as well as
    // the number of triangles generated along these voxel rows.
1116
    Pass2<T> pass2(&algo);
1117
    vtkSMPTools::For(0,algo.Dims[2]-1, pass2);
1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174

    // PASS 3: Now allocate and generate output. First we have to update the
    // edge meta data to partition the output into separate pieces so
    // independent threads can write without collisions. Once allocation is
    // complete, the volume is processed on a voxel row by row basis to
    // produce output points and triangles, and interpolate point attribute
    // data (as necessary).
    numOutXPts = startXPts;
    numOutYPts = startYPts;
    numOutZPts = startZPts;
    numOutTris = startTris;

    // Count number of points and tris generate along each cell row
    for (slice=0; slice < algo.Dims[2]; ++slice)
      {
      zInc = slice * algo.Dims[1];
      for (row=0; row < algo.Dims[1]; ++row)
        {
        eMD = algo.EdgeMetaData + (zInc+row)*6;
        numXPts = eMD[0];
        numYPts = eMD[1];
        numZPts = eMD[2];
        numTris = eMD[3];
        eMD[0] = numOutXPts + numOutYPts + numOutZPts;
        eMD[1] = eMD[0] + numXPts;
        eMD[2] = eMD[1] + numYPts;
        eMD[3] = numOutTris;
        numOutXPts += numXPts;
        numOutYPts += numYPts;
        numOutZPts += numZPts;
        numOutTris += numTris;
        }
      }

    // Output can now be allocated.
    newPts->GetData()->WriteVoidPointer(0,3*(numOutXPts+numOutYPts+numOutZPts));
    algo.NewPoints = static_cast<float*>(newPts->GetVoidPointer(0));
    newTris->WritePointer(numOutTris,4*numOutTris);
    algo.NewTris = static_cast<vtkIdType*>(newTris->GetPointer());
    if (newScalars)
      {
      newScalars->WriteVoidPointer(0,(numOutXPts+numOutYPts+numOutZPts));
      algo.NewScalars = static_cast<T*>(newScalars->GetVoidPointer(0));
      }
    if (newGradients)
      {
      newGradients->WriteVoidPointer(0,3*(numOutXPts+numOutYPts+numOutZPts));
      algo.NewGradients = static_cast<float*>(newGradients->GetVoidPointer(0));
      }
    if (newNormals)
      {
      newNormals->WriteVoidPointer(0,3*(numOutXPts+numOutYPts+numOutZPts));
      algo.NewNormals = static_cast<float*>(newNormals->GetVoidPointer(0));
      }
    algo.NeedGradients = (algo.NewGradients || algo.NewNormals ? 1 : 0);

    // Process voxel rows and generate output
1175
    Pass3<T> pass3(&algo,value);
1176
    vtkSMPTools::For(0,algo.Dims[2]-1, pass3);
1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190

    // Handle multiple contours
    startXPts = numOutXPts;
    startYPts = numOutYPts;
    startZPts = numOutZPts;
    startTris = numOutTris;
    }// for all contour values

  // Clean up and return
  delete [] algo.XCases;
  delete [] algo.EdgeMetaData;
}

//----------------------------------------------------------------------------
1191 1192
// Here is the VTK class proper.
// Construct object with a single contour value of 0.0.
1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322
vtkFlyingEdges3D::vtkFlyingEdges3D()
{
  this->ContourValues = vtkContourValues::New();
  this->ComputeNormals = 1;
  this->ComputeGradients = 0;
  this->ComputeScalars = 1;
  this->ArrayComponent = 0;

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

//----------------------------------------------------------------------------
vtkFlyingEdges3D::~vtkFlyingEdges3D()
{
  this->ContourValues->Delete();
}

//----------------------------------------------------------------------------
// Overload standard modified time function. If contour values are modified,
// then this object is modified as well.
unsigned long vtkFlyingEdges3D::GetMTime()
{
  unsigned long mTime=this->Superclass::GetMTime();
  unsigned long mTime2=this->ContourValues->GetMTime();
  return ( mTime2 > mTime ? mTime2 : mTime );
}

//----------------------------------------------------------------------------
int vtkFlyingEdges3D::RequestUpdateExtent(
  vtkInformation *vtkNotUsed(request),
  vtkInformationVector **inputVector,
  vtkInformationVector *outputVector)
{
  // These require extra ghost levels
  if (this->ComputeGradients || this->ComputeNormals)
    {
    vtkInformation *inInfo = inputVector[0]->GetInformationObject(0);
    vtkInformation *outInfo = outputVector->GetInformationObject(0);

    int ghostLevels;
    ghostLevels =
      outInfo->Get(
        vtkStreamingDemandDrivenPipeline::UPDATE_NUMBER_OF_GHOST_LEVELS());
    inInfo->Set(vtkStreamingDemandDrivenPipeline::UPDATE_NUMBER_OF_GHOST_LEVELS(),
                ghostLevels + 1);
    }

  return 1;
}

//----------------------------------------------------------------------------
int vtkFlyingEdges3D::RequestData(
  vtkInformation *request,
  vtkInformationVector **inputVector,
  vtkInformationVector *outputVector)
{
   vtkDebugMacro(<< "Executing 3D structured contour");

  // get the info objects
  vtkInformation *inInfo = inputVector[0]->GetInformationObject(0);
  vtkInformation *outInfo = outputVector->GetInformationObject(0);

  // get the input and output
  vtkImageData *input = vtkImageData::SafeDownCast(
    inInfo->Get(vtkDataObject::DATA_OBJECT()));
  vtkPolyData *output = vtkPolyData::SafeDownCast(
    outInfo->Get(vtkDataObject::DATA_OBJECT()));

  // to be safe recompute the update extent
  this->RequestUpdateExtent(request,inputVector,outputVector);
  vtkDataArray *inScalars = this->GetInputArrayToProcess(0,inputVector);

  // Determine extent
  int* inExt = input->GetExtent();
  int exExt[6];
  inInfo->Get(vtkStreamingDemandDrivenPipeline::UPDATE_EXTENT(), exExt);
  for (int i=0; i<3; i++)
    {
    if (inExt[2*i] > exExt[2*i])
      {
      exExt[2*i] = inExt[2*i];
      }
    if (inExt[2*i+1] < exExt[2*i+1])
      {
      exExt[2*i+1] = inExt[2*i+1];
      }
    }
  if ( exExt[0] >= exExt[1] || exExt[2] >= exExt[3] || exExt[4] >= exExt[5] )
    {
    vtkDebugMacro(<<"3D structured contours requires 3D data");
    return 0;
    }

  // Check data type and execute appropriate function
  //
  if (inScalars == NULL)
    {
    vtkDebugMacro("No scalars for contouring.");
    return 0;
    }
  int numComps = inScalars->GetNumberOfComponents();

  if (this->ArrayComponent >= numComps)
    {
    vtkErrorMacro("Scalars have " << numComps << " components. "
                  "ArrayComponent must be smaller than " << numComps);
    return 0;
    }

  // Create necessary objects to hold output. We will defer the
  // actual allocation to a later point.
  vtkCellArray *newTris = vtkCellArray::New();
  vtkPoints *newPts = vtkPoints::New();
  newPts->SetDataTypeToFloat();
  vtkDataArray *newScalars = NULL;
  vtkFloatArray *newNormals = NULL;
  vtkFloatArray *newGradients = NULL;

  if (this->ComputeScalars)
    {
    newScalars = inScalars->NewInstance();
    newScalars->SetNumberOfComponents(1);
    newScalars->SetName(inScalars->GetName());
    }
  if (this->ComputeNormals)
    {
    newNormals = vtkFloatArray::New();
    newNormals->SetNumberOfComponents(3);
1323
    newNormals->SetName("Gradients");
1324 1325 1326 1327 1328
    }
  if (this->ComputeGradients)
    {
    newGradients = vtkFloatArray::New();
    newGradients->SetNumberOfComponents(3);
1329
    newGradients->SetName("Gradients");
1330 1331 1332 1333 1334 1335
    }

  void *ptr = input->GetArrayPointerForExtent(inScalars, exExt);
  vtkIdType *incs = input->GetIncrements();
  switch (inScalars->GetDataType())
    {
1336 1337 1338 1339
    vtkTemplateMacro(vtkFlyingEdges3DAlgorithm<VTK_TT>::
                     Contour(this, input, exExt, incs, (VTK_TT *)ptr,
                             newPts, newTris, newScalars, newNormals,
                             newGradients));
1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395
    }

  vtkDebugMacro(<<"Created: "
                << newPts->GetNumberOfPoints() << " points, "
                << newTris->GetNumberOfCells() << " triangles");

  // Update ourselves.  Because we don't know up front how many lines
  // we've created, take care to reclaim memory.
  output->SetPoints(newPts);
  newPts->Delete();

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

  if (newScalars)
    {
    int idx = output->GetPointData()->AddArray(newScalars);
    output->GetPointData()->SetActiveAttribute(idx, vtkDataSetAttributes::SCALARS);
    newScalars->Delete();
    }

  if (newNormals)
    {
    int idx = output->GetPointData()->AddArray(newNormals);
    output->GetPointData()->SetActiveAttribute(idx, vtkDataSetAttributes::NORMALS);
    newNormals->Delete();
    }

  if (newGradients)
    {
    output->GetPointData()->AddArray(newGradients);
    newGradients->Delete();
    }

  return 1;
}

//----------------------------------------------------------------------------
int vtkFlyingEdges3D::FillInputPortInformation(int, vtkInformation *info)
{
  info->Set(vtkAlgorithm::INPUT_REQUIRED_DATA_TYPE(), "vtkImageData");
  return 1;
}

//----------------------------------------------------------------------------
void vtkFlyingEdges3D::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os,indent);

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

  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");
  os << indent << "ArrayComponent: " << this->ArrayComponent << endl;
}