CCGSubSurf.cc

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/* SPDX-FileCopyrightText: 2023 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
 
#include <cmath>
#include <cstdlib>
#include <cstring>
 
#include "BLI_sys_types.h" /* for intptr_t support */
#include "MEM_guardedalloc.h"
 
#include "BLI_utildefines.h" /* for BLI_assert */
 
#include "BKE_ccg.hh"
#include "BKE_subsurf.hh"
#include "CCGSubSurf.h"
#include "CCGSubSurf_intern.h"
 
/***/
 
int BKE_ccg_gridsize(int level)
{
  return ccg_gridsize(level);
}
 
int BKE_ccg_factor(int low_level, int high_level)
{
  BLI_assert(low_level > 0 && high_level > 0);
  BLI_assert(low_level <= high_level);
 
  return 1 << (high_level - low_level);
}
 
/***/
 
static CCGVert *_vert_new(CCGVertHDL vHDL, CCGSubSurf *ss)
{
  int num_vert_data = ss->subdivLevels + 1;
  CCGVert *v = static_cast<CCGVert *>(CCGSUBSURF_alloc(
      ss, sizeof(CCGVert) + ss->meshIFC.vertDataSize * num_vert_data + ss->meshIFC.vertUserSize));
  byte *user_data;
 
  v->vHDL = vHDL;
  v->edges = nullptr;
  v->faces = nullptr;
  v->numEdges = v->numFaces = 0;
  v->flags = 0;
 
  user_data = static_cast<byte *>(ccgSubSurf_getVertUserData(ss, v));
  memset(user_data, 0, ss->meshIFC.vertUserSize);
  if (ss->useAgeCounts) {
    *((int *)&user_data[ss->vertUserAgeOffset]) = ss->currentAge;
  }
 
  return v;
}
static void _vert_remEdge(CCGVert *v, CCGEdge *e)
{
  for (int i = 0; i < v->numEdges; i++) {
    if (v->edges[i] == e) {
      v->edges[i] = v->edges[--v->numEdges];
      break;
    }
  }
}
static void _vert_remFace(CCGVert *v, CCGFace *f)
{
  for (int i = 0; i < v->numFaces; i++) {
    if (v->faces[i] == f) {
      v->faces[i] = v->faces[--v->numFaces];
      break;
    }
  }
}
static void _vert_addEdge(CCGVert *v, CCGEdge *e, CCGSubSurf *ss)
{
  v->edges = static_cast<CCGEdge **>(CCGSUBSURF_realloc(
      ss, v->edges, (v->numEdges + 1) * sizeof(*v->edges), v->numEdges * sizeof(*v->edges)));
  v->edges[v->numEdges++] = e;
}
static void _vert_addFace(CCGVert *v, CCGFace *f, CCGSubSurf *ss)
{
  v->faces = static_cast<CCGFace **>(CCGSUBSURF_realloc(
      ss, v->faces, (v->numFaces + 1) * sizeof(*v->faces), v->numFaces * sizeof(*v->faces)));
  v->faces[v->numFaces++] = f;
}
static CCGEdge *_vert_findEdgeTo(const CCGVert *v, const CCGVert *vQ)
{
  for (int i = 0; i < v->numEdges; i++) {
    CCGEdge *e = v->edges[v->numEdges - 1 - i]; /* XXX, note reverse. */
    if ((e->v0 == v && e->v1 == vQ) || (e->v1 == v && e->v0 == vQ)) {
      return e;
    }
  }
  return nullptr;
}
static void _vert_free(CCGVert *v, CCGSubSurf *ss)
{
  if (v->edges) {
    CCGSUBSURF_free(ss, v->edges);
  }
 
  if (v->faces) {
    CCGSUBSURF_free(ss, v->faces);
  }
 
  CCGSUBSURF_free(ss, v);
}
 
/***/
 
static CCGEdge *_edge_new(CCGEdgeHDL eHDL, CCGVert *v0, CCGVert *v1, float crease, CCGSubSurf *ss)
{
  int num_edge_data = ccg_edgebase(ss->subdivLevels + 1);
  CCGEdge *e = static_cast<CCGEdge *>(CCGSUBSURF_alloc(
      ss, sizeof(CCGEdge) + ss->meshIFC.vertDataSize * num_edge_data + ss->meshIFC.edgeUserSize));
  byte *user_data;
 
  e->eHDL = eHDL;
  e->v0 = v0;
  e->v1 = v1;
  e->crease = crease;
  e->faces = nullptr;
  e->numFaces = 0;
  e->flags = 0;
  _vert_addEdge(v0, e, ss);
  _vert_addEdge(v1, e, ss);
 
  user_data = static_cast<byte *>(ccgSubSurf_getEdgeUserData(ss, e));
  memset(user_data, 0, ss->meshIFC.edgeUserSize);
  if (ss->useAgeCounts) {
    *((int *)&user_data[ss->edgeUserAgeOffset]) = ss->currentAge;
  }
 
  return e;
}
static void _edge_remFace(CCGEdge *e, CCGFace *f)
{
  for (int i = 0; i < e->numFaces; i++) {
    if (e->faces[i] == f) {
      e->faces[i] = e->faces[--e->numFaces];
      break;
    }
  }
}
static void _edge_addFace(CCGEdge *e, CCGFace *f, CCGSubSurf *ss)
{
  e->faces = static_cast<CCGFace **>(CCGSUBSURF_realloc(
      ss, e->faces, (e->numFaces + 1) * sizeof(*e->faces), e->numFaces * sizeof(*e->faces)));
  e->faces[e->numFaces++] = f;
}
static void *_edge_getCoVert(CCGEdge *e, CCGVert *v, int lvl, int x, int dataSize)
{
  int levelBase = ccg_edgebase(lvl);
  if (v == e->v0) {
    return &EDGE_getLevelData(e)[dataSize * (levelBase + x)];
  }
  return &EDGE_getLevelData(e)[dataSize * (levelBase + (1 << lvl) - x)];
}
 
static void _edge_free(CCGEdge *e, CCGSubSurf *ss)
{
  if (e->faces) {
    CCGSUBSURF_free(ss, e->faces);
  }
 
  CCGSUBSURF_free(ss, e);
}
static void _edge_unlinkMarkAndFree(CCGEdge *e, CCGSubSurf *ss)
{
  _vert_remEdge(e->v0, e);
  _vert_remEdge(e->v1, e);
  e->v0->flags |= Vert_eEffected;
  e->v1->flags |= Vert_eEffected;
  _edge_free(e, ss);
}
 
static CCGFace *_face_new(
    CCGFaceHDL fHDL, CCGVert **verts, CCGEdge **edges, int numVerts, CCGSubSurf *ss)
{
  int maxGridSize = ccg_gridsize(ss->subdivLevels);
  int num_face_data = (numVerts * maxGridSize + numVerts * maxGridSize * maxGridSize + 1);
  CCGFace *f = static_cast<CCGFace *>(CCGSUBSURF_alloc(
      ss,
      sizeof(CCGFace) + sizeof(CCGVert *) * numVerts + sizeof(CCGEdge *) * numVerts +
          ss->meshIFC.vertDataSize * num_face_data + ss->meshIFC.faceUserSize));
  byte *user_data;
 
  f->numVerts = numVerts;
  BLI_assert(numVerts > 2);
  f->fHDL = fHDL;
  f->flags = 0;
 
  for (int i = 0; i < numVerts; i++) {
    FACE_getVerts(f)[i] = verts[i];
    FACE_getEdges(f)[i] = edges[i];
    _vert_addFace(verts[i], f, ss);
    _edge_addFace(edges[i], f, ss);
  }
 
  user_data = static_cast<byte *>(ccgSubSurf_getFaceUserData(ss, f));
  memset(user_data, 0, ss->meshIFC.faceUserSize);
  if (ss->useAgeCounts) {
    *((int *)&user_data[ss->faceUserAgeOffset]) = ss->currentAge;
  }
 
  return f;
}
static void _face_free(CCGFace *f, CCGSubSurf *ss)
{
  CCGSUBSURF_free(ss, f);
}
static void _face_unlinkMarkAndFree(CCGFace *f, CCGSubSurf *ss)
{
  int j;
  for (j = 0; j < f->numVerts; j++) {
    _vert_remFace(FACE_getVerts(f)[j], f);
    _edge_remFace(FACE_getEdges(f)[j], f);
    FACE_getVerts(f)[j]->flags |= Vert_eEffected;
  }
  _face_free(f, ss);
}
 
/***/
 
CCGSubSurf *ccgSubSurf_new(CCGMeshIFC *ifc,
                           int subdivLevels,
                           CCGAllocatorIFC *allocatorIFC,
                           CCGAllocatorHDL allocator)
{
  if (!allocatorIFC) {
    allocatorIFC = ccg_getStandardAllocatorIFC();
    allocator = nullptr;
  }
 
  if (subdivLevels < 1) {
    return nullptr;
  }
 
  CCGSubSurf *ss = static_cast<CCGSubSurf *>(allocatorIFC->alloc(allocator, sizeof(*ss)));
 
  ss->allocatorIFC = *allocatorIFC;
  ss->allocator = allocator;
 
  ss->vMap = ccg_ehash_new(0, &ss->allocatorIFC, ss->allocator);
  ss->eMap = ccg_ehash_new(0, &ss->allocatorIFC, ss->allocator);
  ss->fMap = ccg_ehash_new(0, &ss->allocatorIFC, ss->allocator);
 
  ss->meshIFC = *ifc;
 
  ss->subdivLevels = subdivLevels;
  ss->numGrids = 0;
  ss->allowEdgeCreation = 0;
  ss->defaultCreaseValue = 0;
  ss->defaultEdgeUserData = nullptr;
 
  ss->useAgeCounts = 0;
  ss->vertUserAgeOffset = ss->edgeUserAgeOffset = ss->faceUserAgeOffset = 0;
 
  ss->calcVertNormals = 0;
  ss->normalDataOffset = 0;
 
  ss->allocMask = 0;
 
  ss->q = CCGSUBSURF_alloc(ss, ss->meshIFC.vertDataSize);
  ss->r = CCGSUBSURF_alloc(ss, ss->meshIFC.vertDataSize);
 
  ss->currentAge = 0;
 
  ss->syncState = eSyncState_None;
 
  ss->oldVMap = ss->oldEMap = ss->oldFMap = nullptr;
  ss->lenTempArrays = 0;
  ss->tempVerts = nullptr;
  ss->tempEdges = nullptr;
 
  return ss;
}
 
void ccgSubSurf_free(CCGSubSurf *ss)
{
  CCGAllocatorIFC allocatorIFC = ss->allocatorIFC;
  CCGAllocatorHDL allocator = ss->allocator;
 
  if (ss->syncState) {
    ccg_ehash_free(ss->oldFMap, (EHEntryFreeFP)_face_free, ss);
    ccg_ehash_free(ss->oldEMap, (EHEntryFreeFP)_edge_free, ss);
    ccg_ehash_free(ss->oldVMap, (EHEntryFreeFP)_vert_free, ss);
 
    MEM_freeN(ss->tempVerts);
    MEM_freeN(ss->tempEdges);
  }
 
  CCGSUBSURF_free(ss, ss->r);
  CCGSUBSURF_free(ss, ss->q);
  if (ss->defaultEdgeUserData) {
    CCGSUBSURF_free(ss, ss->defaultEdgeUserData);
  }
 
  ccg_ehash_free(ss->fMap, (EHEntryFreeFP)_face_free, ss);
  ccg_ehash_free(ss->eMap, (EHEntryFreeFP)_edge_free, ss);
  ccg_ehash_free(ss->vMap, (EHEntryFreeFP)_vert_free, ss);
 
  CCGSUBSURF_free(ss, ss);
 
  if (allocatorIFC.release) {
    allocatorIFC.release(allocator);
  }
}
 
CCGError ccgSubSurf_setAllowEdgeCreation(CCGSubSurf *ss,
                                         int allowEdgeCreation,
                                         float defaultCreaseValue,
                                         void *defaultUserData)
{
  if (ss->defaultEdgeUserData) {
    CCGSUBSURF_free(ss, ss->defaultEdgeUserData);
  }
 
  ss->allowEdgeCreation = !!allowEdgeCreation;
  ss->defaultCreaseValue = defaultCreaseValue;
  ss->defaultEdgeUserData = CCGSUBSURF_alloc(ss, ss->meshIFC.edgeUserSize);
 
  if (defaultUserData) {
    memcpy(ss->defaultEdgeUserData, defaultUserData, ss->meshIFC.edgeUserSize);
  }
  else {
    memset(ss->defaultEdgeUserData, 0, ss->meshIFC.edgeUserSize);
  }
 
  return eCCGError_None;
}
void ccgSubSurf_getAllowEdgeCreation(CCGSubSurf *ss,
                                     int *allowEdgeCreation_r,
                                     float *defaultCreaseValue_r,
                                     void *defaultUserData_r)
{
  if (allowEdgeCreation_r) {
    *allowEdgeCreation_r = ss->allowEdgeCreation;
  }
  if (ss->allowEdgeCreation) {
    if (defaultCreaseValue_r) {
      *defaultCreaseValue_r = ss->defaultCreaseValue;
    }
    if (defaultUserData_r) {
      memcpy(defaultUserData_r, ss->defaultEdgeUserData, ss->meshIFC.edgeUserSize);
    }
  }
}
 
CCGError ccgSubSurf_setSubdivisionLevels(CCGSubSurf *ss, int subdivisionLevels)
{
  if (subdivisionLevels <= 0) {
    return eCCGError_InvalidValue;
  }
  if (subdivisionLevels != ss->subdivLevels) {
    ss->numGrids = 0;
    ss->subdivLevels = subdivisionLevels;
    ccg_ehash_free(ss->vMap, (EHEntryFreeFP)_vert_free, ss);
    ccg_ehash_free(ss->eMap, (EHEntryFreeFP)_edge_free, ss);
    ccg_ehash_free(ss->fMap, (EHEntryFreeFP)_face_free, ss);
    ss->vMap = ccg_ehash_new(0, &ss->allocatorIFC, ss->allocator);
    ss->eMap = ccg_ehash_new(0, &ss->allocatorIFC, ss->allocator);
    ss->fMap = ccg_ehash_new(0, &ss->allocatorIFC, ss->allocator);
  }
 
  return eCCGError_None;
}
 
void ccgSubSurf_getUseAgeCounts(CCGSubSurf *ss,
                                int *useAgeCounts_r,
                                int *vertUserOffset_r,
                                int *edgeUserOffset_r,
                                int *faceUserOffset_r)
{
  *useAgeCounts_r = ss->useAgeCounts;
 
  if (vertUserOffset_r) {
    *vertUserOffset_r = ss->vertUserAgeOffset;
  }
  if (edgeUserOffset_r) {
    *edgeUserOffset_r = ss->edgeUserAgeOffset;
  }
  if (faceUserOffset_r) {
    *faceUserOffset_r = ss->faceUserAgeOffset;
  }
}
 
CCGError ccgSubSurf_setUseAgeCounts(
    CCGSubSurf *ss, int useAgeCounts, int vertUserOffset, int edgeUserOffset, int faceUserOffset)
{
  if (useAgeCounts) {
    if ((vertUserOffset + 4 > ss->meshIFC.vertUserSize) ||
        (edgeUserOffset + 4 > ss->meshIFC.edgeUserSize) ||
        (faceUserOffset + 4 > ss->meshIFC.faceUserSize))
    {
      return eCCGError_InvalidValue;
    }
    ss->useAgeCounts = 1;
    ss->vertUserAgeOffset = vertUserOffset;
    ss->edgeUserAgeOffset = edgeUserOffset;
    ss->faceUserAgeOffset = faceUserOffset;
  }
  else {
    ss->useAgeCounts = 0;
    ss->vertUserAgeOffset = ss->edgeUserAgeOffset = ss->faceUserAgeOffset = 0;
  }
 
  return eCCGError_None;
}
 
CCGError ccgSubSurf_setCalcVertexNormals(CCGSubSurf *ss, int useVertNormals, int normalDataOffset)
{
  if (useVertNormals) {
    if (normalDataOffset < 0 || normalDataOffset + 12 > ss->meshIFC.vertDataSize) {
      return eCCGError_InvalidValue;
    }
    ss->calcVertNormals = 1;
    ss->normalDataOffset = normalDataOffset;
  }
  else {
    ss->calcVertNormals = 0;
    ss->normalDataOffset = 0;
  }
 
  return eCCGError_None;
}
 
void ccgSubSurf_setAllocMask(CCGSubSurf *ss, int allocMask, int maskOffset)
{
  ss->allocMask = allocMask;
  ss->maskDataOffset = maskOffset;
}
 
void ccgSubSurf_setNumLayers(CCGSubSurf *ss, int numLayers)
{
  ss->meshIFC.numLayers = numLayers;
}
 
/***/
 
CCGError ccgSubSurf_initFullSync(CCGSubSurf *ss)
{
  if (ss->syncState != eSyncState_None) {
    return eCCGError_InvalidSyncState;
  }
 
  ss->currentAge++;
 
  ss->oldVMap = ss->vMap;
  ss->oldEMap = ss->eMap;
  ss->oldFMap = ss->fMap;
 
  ss->vMap = ccg_ehash_new(0, &ss->allocatorIFC, ss->allocator);
  ss->eMap = ccg_ehash_new(0, &ss->allocatorIFC, ss->allocator);
  ss->fMap = ccg_ehash_new(0, &ss->allocatorIFC, ss->allocator);
 
  ss->numGrids = 0;
 
  ss->lenTempArrays = 12;
  ss->tempVerts = static_cast<CCGVert **>(
      MEM_mallocN(sizeof(*ss->tempVerts) * ss->lenTempArrays, "CCGSubsurf tempVerts"));
  ss->tempEdges = static_cast<CCGEdge **>(
      MEM_mallocN(sizeof(*ss->tempEdges) * ss->lenTempArrays, "CCGSubsurf tempEdges"));
 
  ss->syncState = eSyncState_Vert;
 
  return eCCGError_None;
}
 
CCGError ccgSubSurf_initPartialSync(CCGSubSurf *ss)
{
  if (ss->syncState != eSyncState_None) {
    return eCCGError_InvalidSyncState;
  }
 
  ss->currentAge++;
 
  ss->syncState = eSyncState_Partial;
 
  return eCCGError_None;
}
 
CCGError ccgSubSurf_syncVertDel(CCGSubSurf *ss, CCGVertHDL vHDL)
{
  if (ss->syncState != eSyncState_Partial) {
    return eCCGError_InvalidSyncState;
  }
 
  void **prevp;
  CCGVert *v = static_cast<CCGVert *>(ccg_ehash_lookupWithPrev(ss->vMap, vHDL, &prevp));
 
  if (!v || v->numFaces || v->numEdges) {
    return eCCGError_InvalidValue;
  }
 
  *prevp = v->next;
  _vert_free(v, ss);
 
  return eCCGError_None;
}
 
CCGError ccgSubSurf_syncEdgeDel(CCGSubSurf *ss, CCGEdgeHDL eHDL)
{
  if (ss->syncState != eSyncState_Partial) {
    return eCCGError_InvalidSyncState;
  }
 
  void **prevp;
  CCGEdge *e = static_cast<CCGEdge *>(ccg_ehash_lookupWithPrev(ss->eMap, eHDL, &prevp));
 
  if (!e || e->numFaces) {
    return eCCGError_InvalidValue;
  }
 
  *prevp = e->next;
  _edge_unlinkMarkAndFree(e, ss);
 
  return eCCGError_None;
}
 
CCGError ccgSubSurf_syncFaceDel(CCGSubSurf *ss, CCGFaceHDL fHDL)
{
  if (ss->syncState != eSyncState_Partial) {
    return eCCGError_InvalidSyncState;
  }
 
  void **prevp;
  CCGFace *f = static_cast<CCGFace *>(ccg_ehash_lookupWithPrev(ss->fMap, fHDL, &prevp));
 
  if (!f) {
    return eCCGError_InvalidValue;
  }
 
  *prevp = f->next;
  _face_unlinkMarkAndFree(f, ss);
 
  return eCCGError_None;
}
 
CCGError ccgSubSurf_syncVert(
    CCGSubSurf *ss, CCGVertHDL vHDL, const void *vertData, int seam, CCGVert **v_r)
{
  void **prevp;
  CCGVert *v = nullptr;
  short seamflag = (seam) ? Vert_eSeam : 0;
 
  if (ss->syncState == eSyncState_Partial) {
    v = static_cast<CCGVert *>(ccg_ehash_lookupWithPrev(ss->vMap, vHDL, &prevp));
    if (!v) {
      v = _vert_new(vHDL, ss);
      VertDataCopy(static_cast<float *>(ccg_vert_getCo(v, 0, ss->meshIFC.vertDataSize)),
                   static_cast<const float *>(vertData),
                   ss);
      ccg_ehash_insert(ss->vMap, (EHEntry *)v);
      v->flags = Vert_eEffected | seamflag;
    }
    else if (!VertDataEqual(
                 static_cast<const float *>(vertData),
                 static_cast<const float *>(ccg_vert_getCo(v, 0, ss->meshIFC.vertDataSize)),
                 ss) ||
             ((v->flags & Vert_eSeam) != seamflag))
    {
      int i, j;
 
      VertDataCopy(static_cast<float *>(ccg_vert_getCo(v, 0, ss->meshIFC.vertDataSize)),
                   static_cast<const float *>(vertData),
                   ss);
      v->flags = Vert_eEffected | seamflag;
 
      for (i = 0; i < v->numEdges; i++) {
        CCGEdge *e = v->edges[i];
        e->v0->flags |= Vert_eEffected;
        e->v1->flags |= Vert_eEffected;
      }
      for (i = 0; i < v->numFaces; i++) {
        CCGFace *f = v->faces[i];
        for (j = 0; j < f->numVerts; j++) {
          FACE_getVerts(f)[j]->flags |= Vert_eEffected;
        }
      }
    }
  }
  else {
    if (ss->syncState != eSyncState_Vert) {
      return eCCGError_InvalidSyncState;
    }
 
    v = static_cast<CCGVert *>(ccg_ehash_lookupWithPrev(ss->oldVMap, vHDL, &prevp));
    if (!v) {
      v = _vert_new(vHDL, ss);
      VertDataCopy(static_cast<float *>(ccg_vert_getCo(v, 0, ss->meshIFC.vertDataSize)),
                   static_cast<const float *>(vertData),
                   ss);
      ccg_ehash_insert(ss->vMap, (EHEntry *)v);
      v->flags = Vert_eEffected | seamflag;
    }
    else if (!VertDataEqual(
                 static_cast<const float *>(vertData),
                 static_cast<const float *>(ccg_vert_getCo(v, 0, ss->meshIFC.vertDataSize)),
                 ss) ||
             ((v->flags & Vert_eSeam) != seamflag))
    {
      *prevp = v->next;
      ccg_ehash_insert(ss->vMap, (EHEntry *)v);
      VertDataCopy(static_cast<float *>(ccg_vert_getCo(v, 0, ss->meshIFC.vertDataSize)),
                   static_cast<const float *>(vertData),
                   ss);
      v->flags = Vert_eEffected | Vert_eChanged | seamflag;
    }
    else {
      *prevp = v->next;
      ccg_ehash_insert(ss->vMap, (EHEntry *)v);
      v->flags = 0;
    }
  }
 
  if (v_r) {
    *v_r = v;
  }
  return eCCGError_None;
}
 
CCGError ccgSubSurf_syncEdge(CCGSubSurf *ss,
                             CCGEdgeHDL eHDL,
                             CCGVertHDL e_vHDL0,
                             CCGVertHDL e_vHDL1,
                             float crease,
                             CCGEdge **e_r)
{
  void **prevp;
  CCGEdge *e = nullptr, *eNew;
 
  if (ss->syncState == eSyncState_Partial) {
    e = static_cast<CCGEdge *>(ccg_ehash_lookupWithPrev(ss->eMap, eHDL, &prevp));
    if (!e || e->v0->vHDL != e_vHDL0 || e->v1->vHDL != e_vHDL1 || crease != e->crease) {
      CCGVert *v0 = static_cast<CCGVert *>(ccg_ehash_lookup(ss->vMap, e_vHDL0));
      CCGVert *v1 = static_cast<CCGVert *>(ccg_ehash_lookup(ss->vMap, e_vHDL1));
 
      eNew = _edge_new(eHDL, v0, v1, crease, ss);
 
      if (e) {
        *prevp = eNew;
        eNew->next = e->next;
 
        _edge_unlinkMarkAndFree(e, ss);
      }
      else {
        ccg_ehash_insert(ss->eMap, (EHEntry *)eNew);
      }
 
      eNew->v0->flags |= Vert_eEffected;
      eNew->v1->flags |= Vert_eEffected;
    }
  }
  else {
    if (ss->syncState == eSyncState_Vert) {
      ss->syncState = eSyncState_Edge;
    }
    else if (ss->syncState != eSyncState_Edge) {
      return eCCGError_InvalidSyncState;
    }
 
    e = static_cast<CCGEdge *>(ccg_ehash_lookupWithPrev(ss->oldEMap, eHDL, &prevp));
    if (!e || e->v0->vHDL != e_vHDL0 || e->v1->vHDL != e_vHDL1 || e->crease != crease) {
      CCGVert *v0 = static_cast<CCGVert *>(ccg_ehash_lookup(ss->vMap, e_vHDL0));
      CCGVert *v1 = static_cast<CCGVert *>(ccg_ehash_lookup(ss->vMap, e_vHDL1));
      e = _edge_new(eHDL, v0, v1, crease, ss);
      ccg_ehash_insert(ss->eMap, (EHEntry *)e);
      e->v0->flags |= Vert_eEffected;
      e->v1->flags |= Vert_eEffected;
    }
    else {
      *prevp = e->next;
      ccg_ehash_insert(ss->eMap, (EHEntry *)e);
      e->flags = 0;
      if ((e->v0->flags | e->v1->flags) & Vert_eChanged) {
        e->v0->flags |= Vert_eEffected;
        e->v1->flags |= Vert_eEffected;
      }
    }
  }
 
  if (e_r) {
    *e_r = e;
  }
  return eCCGError_None;
}
 
CCGError ccgSubSurf_syncFace(
    CCGSubSurf *ss, CCGFaceHDL fHDL, int numVerts, CCGVertHDL *vHDLs, CCGFace **f_r)
{
  void **prevp;
  CCGFace *f = nullptr, *fNew;
  int j, k, topologyChanged = 0;
 
  if (UNLIKELY(numVerts > ss->lenTempArrays)) {
    ss->lenTempArrays = (numVerts < ss->lenTempArrays * 2) ? ss->lenTempArrays * 2 : numVerts;
    ss->tempVerts = static_cast<CCGVert **>(
        MEM_reallocN(ss->tempVerts, sizeof(*ss->tempVerts) * ss->lenTempArrays));
    ss->tempEdges = static_cast<CCGEdge **>(
        MEM_reallocN(ss->tempEdges, sizeof(*ss->tempEdges) * ss->lenTempArrays));
  }
 
  if (ss->syncState == eSyncState_Partial) {
    f = static_cast<CCGFace *>(ccg_ehash_lookupWithPrev(ss->fMap, fHDL, &prevp));
 
    for (k = 0; k < numVerts; k++) {
      ss->tempVerts[k] = static_cast<CCGVert *>(ccg_ehash_lookup(ss->vMap, vHDLs[k]));
    }
    for (k = 0; k < numVerts; k++) {
      ss->tempEdges[k] = _vert_findEdgeTo(ss->tempVerts[k], ss->tempVerts[(k + 1) % numVerts]);
    }
 
    if (f) {
      if (f->numVerts != numVerts ||
          memcmp(FACE_getVerts(f), ss->tempVerts, sizeof(*ss->tempVerts) * numVerts) != 0 ||
          memcmp(FACE_getEdges(f), ss->tempEdges, sizeof(*ss->tempEdges) * numVerts) != 0)
      {
        topologyChanged = 1;
      }
    }
 
    if (!f || topologyChanged) {
      fNew = _face_new(fHDL, ss->tempVerts, ss->tempEdges, numVerts, ss);
 
      if (f) {
        ss->numGrids += numVerts - f->numVerts;
 
        *prevp = fNew;
        fNew->next = f->next;
 
        _face_unlinkMarkAndFree(f, ss);
      }
      else {
        ss->numGrids += numVerts;
        ccg_ehash_insert(ss->fMap, (EHEntry *)fNew);
      }
 
      for (k = 0; k < numVerts; k++) {
        FACE_getVerts(fNew)[k]->flags |= Vert_eEffected;
      }
    }
  }
  else {
    if (ELEM(ss->syncState, eSyncState_Vert, eSyncState_Edge)) {
      ss->syncState = eSyncState_Face;
    }
    else if (ss->syncState != eSyncState_Face) {
      return eCCGError_InvalidSyncState;
    }
 
    f = static_cast<CCGFace *>(ccg_ehash_lookupWithPrev(ss->oldFMap, fHDL, &prevp));
 
    for (k = 0; k < numVerts; k++) {
      ss->tempVerts[k] = static_cast<CCGVert *>(ccg_ehash_lookup(ss->vMap, vHDLs[k]));
 
      if (!ss->tempVerts[k]) {
        return eCCGError_InvalidValue;
      }
    }
    for (k = 0; k < numVerts; k++) {
      ss->tempEdges[k] = _vert_findEdgeTo(ss->tempVerts[k], ss->tempVerts[(k + 1) % numVerts]);
 
      if (!ss->tempEdges[k]) {
        if (ss->allowEdgeCreation) {
          CCGEdge *e = ss->tempEdges[k] = _edge_new((CCGEdgeHDL)-1,
                                                    ss->tempVerts[k],
                                                    ss->tempVerts[(k + 1) % numVerts],
                                                    ss->defaultCreaseValue,
                                                    ss);
          ccg_ehash_insert(ss->eMap, (EHEntry *)e);
          e->v0->flags |= Vert_eEffected;
          e->v1->flags |= Vert_eEffected;
          if (ss->meshIFC.edgeUserSize) {
            memcpy(ccgSubSurf_getEdgeUserData(ss, e),
                   ss->defaultEdgeUserData,
                   ss->meshIFC.edgeUserSize);
          }
        }
        else {
          return eCCGError_InvalidValue;
        }
      }
    }
 
    if (f) {
      if (f->numVerts != numVerts ||
          memcmp(FACE_getVerts(f), ss->tempVerts, sizeof(*ss->tempVerts) * numVerts) != 0 ||
          memcmp(FACE_getEdges(f), ss->tempEdges, sizeof(*ss->tempEdges) * numVerts) != 0)
      {
        topologyChanged = 1;
      }
    }
 
    if (!f || topologyChanged) {
      f = _face_new(fHDL, ss->tempVerts, ss->tempEdges, numVerts, ss);
      ccg_ehash_insert(ss->fMap, (EHEntry *)f);
      ss->numGrids += numVerts;
 
      for (k = 0; k < numVerts; k++) {
        FACE_getVerts(f)[k]->flags |= Vert_eEffected;
      }
    }
    else {
      *prevp = f->next;
      ccg_ehash_insert(ss->fMap, (EHEntry *)f);
      f->flags = 0;
      ss->numGrids += f->numVerts;
 
      for (j = 0; j < f->numVerts; j++) {
        if (FACE_getVerts(f)[j]->flags & Vert_eChanged) {
          for (k = 0; k < f->numVerts; k++) {
            FACE_getVerts(f)[k]->flags |= Vert_eEffected;
          }
          break;
        }
      }
    }
  }
 
  if (f_r) {
    *f_r = f;
  }
  return eCCGError_None;
}
 
static void ccgSubSurf__sync(CCGSubSurf *ss)
{
  ccgSubSurf__sync_legacy(ss);
}
 
CCGError ccgSubSurf_processSync(CCGSubSurf *ss)
{
  if (ss->syncState == eSyncState_Partial) {
    ss->syncState = eSyncState_None;
 
    ccgSubSurf__sync(ss);
  }
  else if (ss->syncState) {
    ccg_ehash_free(ss->oldFMap, (EHEntryFreeFP)_face_unlinkMarkAndFree, ss);
    ccg_ehash_free(ss->oldEMap, (EHEntryFreeFP)_edge_unlinkMarkAndFree, ss);
    ccg_ehash_free(ss->oldVMap, (EHEntryFreeFP)_vert_free, ss);
    MEM_freeN(ss->tempEdges);
    MEM_freeN(ss->tempVerts);
 
    ss->lenTempArrays = 0;
 
    ss->oldFMap = ss->oldEMap = ss->oldVMap = nullptr;
    ss->tempVerts = nullptr;
    ss->tempEdges = nullptr;
 
    ss->syncState = eSyncState_None;
 
    ccgSubSurf__sync(ss);
  }
  else {
    return eCCGError_InvalidSyncState;
  }
 
  return eCCGError_None;
}
 
void ccgSubSurf__allFaces(CCGSubSurf *ss, CCGFace ***faces, int *numFaces, int *freeFaces)
{
  CCGFace **array;
  int i, num;
 
  if (*faces == nullptr) {
    array = static_cast<CCGFace **>(
        MEM_mallocN(sizeof(*array) * ss->fMap->numEntries, "CCGSubsurf allFaces"));
    num = 0;
    for (i = 0; i < ss->fMap->curSize; i++) {
      CCGFace *f = (CCGFace *)ss->fMap->buckets[i];
 
      for (; f; f = f->next) {
        array[num++] = f;
      }
    }
 
    *faces = array;
    *numFaces = num;
    *freeFaces = 1;
  }
  else {
    *freeFaces = 0;
  }
}
 
void ccgSubSurf__effectedFaceNeighbors(CCGSubSurf *ss,
                                       CCGFace **faces,
                                       int numFaces,
                                       CCGVert ***verts,
                                       int *numVerts,
                                       CCGEdge ***edges,
                                       int *numEdges)
{
  CCGVert **arrayV;
  CCGEdge **arrayE;
  int numV, numE, i, j;
 
  arrayV = static_cast<CCGVert **>(
      MEM_mallocN(sizeof(*arrayV) * ss->vMap->numEntries, "CCGSubsurf arrayV"));
  arrayE = static_cast<CCGEdge **>(
      MEM_mallocN(sizeof(*arrayE) * ss->eMap->numEntries, "CCGSubsurf arrayV"));
  numV = numE = 0;
 
  for (i = 0; i < numFaces; i++) {
    CCGFace *f = faces[i];
    f->flags |= Face_eEffected;
  }
 
  for (i = 0; i < ss->vMap->curSize; i++) {
    CCGVert *v = (CCGVert *)ss->vMap->buckets[i];
 
    for (; v; v = v->next) {
      for (j = 0; j < v->numFaces; j++) {
        if (!(v->faces[j]->flags & Face_eEffected)) {
          break;
        }
      }
 
      if (j == v->numFaces) {
        arrayV[numV++] = v;
        v->flags |= Vert_eEffected;
      }
    }
  }
 
  for (i = 0; i < ss->eMap->curSize; i++) {
    CCGEdge *e = (CCGEdge *)ss->eMap->buckets[i];
 
    for (; e; e = e->next) {
      for (j = 0; j < e->numFaces; j++) {
        if (!(e->faces[j]->flags & Face_eEffected)) {
          break;
        }
      }
 
      if (j == e->numFaces) {
        e->flags |= Edge_eEffected;
        arrayE[numE++] = e;
      }
    }
  }
 
  *verts = arrayV;
  *numVerts = numV;
  *edges = arrayE;
  *numEdges = numE;
}
 
CCGError ccgSubSurf_updateFromFaces(CCGSubSurf *ss, int lvl, CCGFace **effectedF, int numEffectedF)
{
  int i, S, x, gridSize, cornerIdx, subdivLevels;
  int vertDataSize = ss->meshIFC.vertDataSize, freeF;
 
  subdivLevels = ss->subdivLevels;
  lvl = (lvl) ? lvl : subdivLevels;
  gridSize = ccg_gridsize(lvl);
  cornerIdx = gridSize - 1;
 
  ccgSubSurf__allFaces(ss, &effectedF, &numEffectedF, &freeF);
 
  for (i = 0; i < numEffectedF; i++) {
    CCGFace *f = effectedF[i];
 
    for (S = 0; S < f->numVerts; S++) {
      CCGEdge *e = FACE_getEdges(f)[S];
      CCGEdge *prevE = FACE_getEdges(f)[(S + f->numVerts - 1) % f->numVerts];
 
      VertDataCopy((float *)FACE_getCenterData(f), FACE_getIFCo(f, lvl, S, 0, 0), ss);
      VertDataCopy(
          VERT_getCo(FACE_getVerts(f)[S], lvl), FACE_getIFCo(f, lvl, S, cornerIdx, cornerIdx), ss);
 
      for (x = 0; x < gridSize; x++) {
        VertDataCopy(FACE_getIECo(f, lvl, S, x), FACE_getIFCo(f, lvl, S, x, 0), ss);
      }
 
      for (x = 0; x < gridSize; x++) {
        int eI = gridSize - 1 - x;
        VertDataCopy(
            static_cast<float *>(_edge_getCoVert(e, FACE_getVerts(f)[S], lvl, eI, vertDataSize)),
            FACE_getIFCo(f, lvl, S, cornerIdx, x),
            ss);
        VertDataCopy(static_cast<float *>(
                         _edge_getCoVert(prevE, FACE_getVerts(f)[S], lvl, eI, vertDataSize)),
                     FACE_getIFCo(f, lvl, S, x, cornerIdx),
                     ss);
      }
    }
  }
 
  if (freeF) {
    MEM_freeN(effectedF);
  }
 
  return eCCGError_None;
}
 
CCGError ccgSubSurf_updateToFaces(CCGSubSurf *ss, int lvl, CCGFace **effectedF, int numEffectedF)
{
  int i, S, x, gridSize, cornerIdx, subdivLevels;
  int vertDataSize = ss->meshIFC.vertDataSize, freeF;
 
  subdivLevels = ss->subdivLevels;
  lvl = (lvl) ? lvl : subdivLevels;
  gridSize = ccg_gridsize(lvl);
  cornerIdx = gridSize - 1;
 
  ccgSubSurf__allFaces(ss, &effectedF, &numEffectedF, &freeF);
 
  for (i = 0; i < numEffectedF; i++) {
    CCGFace *f = effectedF[i];
 
    for (S = 0; S < f->numVerts; S++) {
      int prevS = (S + f->numVerts - 1) % f->numVerts;
      CCGEdge *e = FACE_getEdges(f)[S];
      CCGEdge *prevE = FACE_getEdges(f)[prevS];
 
      for (x = 0; x < gridSize; x++) {
        int eI = gridSize - 1 - x;
        VertDataCopy(FACE_getIFCo(f, lvl, S, cornerIdx, x),
                     static_cast<const float *>(
                         _edge_getCoVert(e, FACE_getVerts(f)[S], lvl, eI, vertDataSize)),
                     ss);
        VertDataCopy(FACE_getIFCo(f, lvl, S, x, cornerIdx),
                     static_cast<const float *>(
                         _edge_getCoVert(prevE, FACE_getVerts(f)[S], lvl, eI, vertDataSize)),
                     ss);
      }
 
      for (x = 1; x < gridSize - 1; x++) {
        VertDataCopy(FACE_getIFCo(f, lvl, S, 0, x), FACE_getIECo(f, lvl, prevS, x), ss);
        VertDataCopy(FACE_getIFCo(f, lvl, S, x, 0), FACE_getIECo(f, lvl, S, x), ss);
      }
 
      VertDataCopy(FACE_getIFCo(f, lvl, S, 0, 0), (float *)FACE_getCenterData(f), ss);
      VertDataCopy(
          FACE_getIFCo(f, lvl, S, cornerIdx, cornerIdx), VERT_getCo(FACE_getVerts(f)[S], lvl), ss);
    }
  }
 
  if (freeF) {
    MEM_freeN(effectedF);
  }
 
  return eCCGError_None;
}
 
CCGError ccgSubSurf_stitchFaces(CCGSubSurf *ss, int lvl, CCGFace **effectedF, int numEffectedF)
{
  CCGVert **effectedV;
  CCGEdge **effectedE;
  int numEffectedV, numEffectedE, freeF;
  int i, S, x, gridSize, cornerIdx, subdivLevels, edgeSize;
  int vertDataSize = ss->meshIFC.vertDataSize;
 
  subdivLevels = ss->subdivLevels;
  lvl = (lvl) ? lvl : subdivLevels;
  gridSize = ccg_gridsize(lvl);
  edgeSize = ccg_edgesize(lvl);
  cornerIdx = gridSize - 1;
 
  ccgSubSurf__allFaces(ss, &effectedF, &numEffectedF, &freeF);
  ccgSubSurf__effectedFaceNeighbors(
      ss, effectedF, numEffectedF, &effectedV, &numEffectedV, &effectedE, &numEffectedE);
 
  /* zero */
  for (i = 0; i < numEffectedV; i++) {
    CCGVert *v = effectedV[i];
    if (v->numFaces) {
      VertDataZero(VERT_getCo(v, lvl), ss);
    }
  }
 
  for (i = 0; i < numEffectedE; i++) {
    CCGEdge *e = effectedE[i];
 
    if (e->numFaces) {
      for (x = 0; x < edgeSize; x++) {
        VertDataZero(EDGE_getCo(e, lvl, x), ss);
      }
    }
  }
 
  /* add */
  for (i = 0; i < numEffectedF; i++) {
    CCGFace *f = effectedF[i];
 
    VertDataZero((float *)FACE_getCenterData(f), ss);
 
    for (S = 0; S < f->numVerts; S++) {
      for (x = 0; x < gridSize; x++) {
        VertDataZero(FACE_getIECo(f, lvl, S, x), ss);
      }
    }
 
    for (S = 0; S < f->numVerts; S++) {
      int prevS = (S + f->numVerts - 1) % f->numVerts;
      CCGEdge *e = FACE_getEdges(f)[S];
      CCGEdge *prevE = FACE_getEdges(f)[prevS];
 
      VertDataAdd((float *)FACE_getCenterData(f), FACE_getIFCo(f, lvl, S, 0, 0), ss);
      if (FACE_getVerts(f)[S]->flags & Vert_eEffected) {
        VertDataAdd(VERT_getCo(FACE_getVerts(f)[S], lvl),
                    FACE_getIFCo(f, lvl, S, cornerIdx, cornerIdx),
                    ss);
      }
 
      for (x = 1; x < gridSize - 1; x++) {
        VertDataAdd(FACE_getIECo(f, lvl, S, x), FACE_getIFCo(f, lvl, S, x, 0), ss);
        VertDataAdd(FACE_getIECo(f, lvl, prevS, x), FACE_getIFCo(f, lvl, S, 0, x), ss);
      }
 
      for (x = 0; x < gridSize - 1; x++) {
        int eI = gridSize - 1 - x;
        if (FACE_getEdges(f)[S]->flags & Edge_eEffected) {
          VertDataAdd(
              static_cast<float *>(_edge_getCoVert(e, FACE_getVerts(f)[S], lvl, eI, vertDataSize)),
              FACE_getIFCo(f, lvl, S, cornerIdx, x),
              ss);
        }
        if (FACE_getEdges(f)[prevS]->flags & Edge_eEffected) {
          if (x != 0) {
            VertDataAdd(static_cast<float *>(
                            _edge_getCoVert(prevE, FACE_getVerts(f)[S], lvl, eI, vertDataSize)),
                        FACE_getIFCo(f, lvl, S, x, cornerIdx),
                        ss);
          }
        }
      }
    }
  }
 
  /* average */
  for (i = 0; i < numEffectedV; i++) {
    CCGVert *v = effectedV[i];
    if (v->numFaces) {
      VertDataMulN(VERT_getCo(v, lvl), 1.0f / v->numFaces, ss);
    }
  }
 
  for (i = 0; i < numEffectedE; i++) {
    CCGEdge *e = effectedE[i];
 
    VertDataCopy(EDGE_getCo(e, lvl, 0), VERT_getCo(e->v0, lvl), ss);
    VertDataCopy(EDGE_getCo(e, lvl, edgeSize - 1), VERT_getCo(e->v1, lvl), ss);
 
    if (e->numFaces) {
      for (x = 1; x < edgeSize - 1; x++) {
        VertDataMulN(EDGE_getCo(e, lvl, x), 1.0f / e->numFaces, ss);
      }
    }
  }
 
  /* copy */
  for (i = 0; i < numEffectedF; i++) {
    CCGFace *f = effectedF[i];
 
    VertDataMulN((float *)FACE_getCenterData(f), 1.0f / f->numVerts, ss);
 
    for (S = 0; S < f->numVerts; S++) {
      for (x = 1; x < gridSize - 1; x++) {
        VertDataMulN(FACE_getIECo(f, lvl, S, x), 0.5f, ss);
      }
    }
 
    for (S = 0; S < f->numVerts; S++) {
      int prevS = (S + f->numVerts - 1) % f->numVerts;
      CCGEdge *e = FACE_getEdges(f)[S];
      CCGEdge *prevE = FACE_getEdges(f)[prevS];
 
      VertDataCopy(FACE_getIFCo(f, lvl, S, 0, 0), (float *)FACE_getCenterData(f), ss);
      VertDataCopy(
          FACE_getIFCo(f, lvl, S, cornerIdx, cornerIdx), VERT_getCo(FACE_getVerts(f)[S], lvl), ss);
 
      for (x = 1; x < gridSize - 1; x++) {
        VertDataCopy(FACE_getIFCo(f, lvl, S, x, 0), FACE_getIECo(f, lvl, S, x), ss);
        VertDataCopy(FACE_getIFCo(f, lvl, S, 0, x), FACE_getIECo(f, lvl, prevS, x), ss);
      }
 
      for (x = 0; x < gridSize - 1; x++) {
        int eI = gridSize - 1 - x;
 
        VertDataCopy(FACE_getIFCo(f, lvl, S, cornerIdx, x),
                     static_cast<const float *>(
                         _edge_getCoVert(e, FACE_getVerts(f)[S], lvl, eI, vertDataSize)),
                     ss);
        VertDataCopy(FACE_getIFCo(f, lvl, S, x, cornerIdx),
                     static_cast<const float *>(
                         _edge_getCoVert(prevE, FACE_getVerts(f)[S], lvl, eI, vertDataSize)),
                     ss);
      }
 
      VertDataCopy(FACE_getIECo(f, lvl, S, 0), (float *)FACE_getCenterData(f), ss);
      VertDataCopy(
          FACE_getIECo(f, lvl, S, gridSize - 1), FACE_getIFCo(f, lvl, S, gridSize - 1, 0), ss);
    }
  }
 
  for (i = 0; i < numEffectedV; i++) {
    effectedV[i]->flags = 0;
  }
  for (i = 0; i < numEffectedE; i++) {
    effectedE[i]->flags = 0;
  }
  for (i = 0; i < numEffectedF; i++) {
    effectedF[i]->flags = 0;
  }
 
  MEM_freeN(effectedE);
  MEM_freeN(effectedV);
  if (freeF) {
    MEM_freeN(effectedF);
  }
 
  return eCCGError_None;
}
 
/*** External API accessor functions ***/
 
int ccgSubSurf_getNumVerts(const CCGSubSurf *ss)
{
  return ss->vMap->numEntries;
}
int ccgSubSurf_getNumEdges(const CCGSubSurf *ss)
{
  return ss->eMap->numEntries;
}
int ccgSubSurf_getNumFaces(const CCGSubSurf *ss)
{
  return ss->fMap->numEntries;
}
 
CCGVert *ccgSubSurf_getVert(CCGSubSurf *ss, CCGVertHDL v)
{
  return (CCGVert *)ccg_ehash_lookup(ss->vMap, v);
}
CCGEdge *ccgSubSurf_getEdge(CCGSubSurf *ss, CCGEdgeHDL e)
{
  return (CCGEdge *)ccg_ehash_lookup(ss->eMap, e);
}
CCGFace *ccgSubSurf_getFace(CCGSubSurf *ss, CCGFaceHDL f)
{
  return (CCGFace *)ccg_ehash_lookup(ss->fMap, f);
}
 
int ccgSubSurf_getSubdivisionLevels(const CCGSubSurf *ss)
{
  return ss->subdivLevels;
}
int ccgSubSurf_getEdgeSize(const CCGSubSurf *ss)
{
  return ccgSubSurf_getEdgeLevelSize(ss, ss->subdivLevels);
}
int ccgSubSurf_getEdgeLevelSize(const CCGSubSurf *ss, int level)
{
  if (level < 1 || level > ss->subdivLevels) {
    return -1;
  }
  return ccg_edgesize(level);
}
int ccgSubSurf_getGridSize(const CCGSubSurf *ss)
{
  return ccgSubSurf_getGridLevelSize(ss, ss->subdivLevels);
}
int ccgSubSurf_getGridLevelSize(const CCGSubSurf *ss, int level)
{
  if (level < 1 || level > ss->subdivLevels) {
    return -1;
  }
  return ccg_gridsize(level);
}
 
int ccgSubSurf_getSimpleSubdiv(const CCGSubSurf *ss)
{
  return ss->meshIFC.simpleSubdiv;
}
 
/* Vert accessors */
 
CCGVertHDL ccgSubSurf_getVertVertHandle(CCGVert *v)
{
  return v->vHDL;
}
int ccgSubSurf_getVertAge(CCGSubSurf *ss, CCGVert *v)
{
  if (ss->useAgeCounts) {
    byte *user_data = static_cast<byte *>(ccgSubSurf_getVertUserData(ss, v));
    return ss->currentAge - *((int *)&user_data[ss->vertUserAgeOffset]);
  }
  return 0;
}
void *ccgSubSurf_getVertUserData(CCGSubSurf *ss, CCGVert *v)
{
  return VERT_getLevelData(v) + ss->meshIFC.vertDataSize * (ss->subdivLevels + 1);
}
int ccgSubSurf_getVertNumFaces(CCGVert *v)
{
  return v->numFaces;
}
CCGFace *ccgSubSurf_getVertFace(CCGVert *v, int index)
{
  if (index < 0 || index >= v->numFaces) {
    return nullptr;
  }
  return v->faces[index];
}
int ccgSubSurf_getVertNumEdges(CCGVert *v)
{
  return v->numEdges;
}
CCGEdge *ccgSubSurf_getVertEdge(CCGVert *v, int index)
{
  if (index < 0 || index >= v->numEdges) {
    return nullptr;
  }
  return v->edges[index];
}
void *ccgSubSurf_getVertData(CCGSubSurf *ss, CCGVert *v)
{
  return ccgSubSurf_getVertLevelData(ss, v, ss->subdivLevels);
}
void *ccgSubSurf_getVertLevelData(CCGSubSurf *ss, CCGVert *v, int level)
{
  if (level < 0 || level > ss->subdivLevels) {
    return nullptr;
  }
  return ccg_vert_getCo(v, level, ss->meshIFC.vertDataSize);
}
 
/* Edge accessors */
 
CCGEdgeHDL ccgSubSurf_getEdgeEdgeHandle(CCGEdge *e)
{
  return e->eHDL;
}
int ccgSubSurf_getEdgeAge(CCGSubSurf *ss, CCGEdge *e)
{
  if (ss->useAgeCounts) {
    byte *user_data = static_cast<byte *>(ccgSubSurf_getEdgeUserData(ss, e));
    return ss->currentAge - *((int *)&user_data[ss->edgeUserAgeOffset]);
  }
  return 0;
}
void *ccgSubSurf_getEdgeUserData(CCGSubSurf *ss, CCGEdge *e)
{
  return (EDGE_getLevelData(e) + ss->meshIFC.vertDataSize * ccg_edgebase(ss->subdivLevels + 1));
}
int ccgSubSurf_getEdgeNumFaces(CCGEdge *e)
{
  return e->numFaces;
}
CCGFace *ccgSubSurf_getEdgeFace(CCGEdge *e, int index)
{
  if (index < 0 || index >= e->numFaces) {
    return nullptr;
  }
  return e->faces[index];
}
CCGVert *ccgSubSurf_getEdgeVert0(CCGEdge *e)
{
  return e->v0;
}
CCGVert *ccgSubSurf_getEdgeVert1(CCGEdge *e)
{
  return e->v1;
}
void *ccgSubSurf_getEdgeDataArray(CCGSubSurf *ss, CCGEdge *e)
{
  return ccgSubSurf_getEdgeData(ss, e, 0);
}
void *ccgSubSurf_getEdgeData(CCGSubSurf *ss, CCGEdge *e, int x)
{
  return ccgSubSurf_getEdgeLevelData(ss, e, x, ss->subdivLevels);
}
void *ccgSubSurf_getEdgeLevelData(CCGSubSurf *ss, CCGEdge *e, int x, int level)
{
  if (level < 0 || level > ss->subdivLevels) {
    return nullptr;
  }
  return ccg_edge_getCo(e, level, x, ss->meshIFC.vertDataSize);
}
float ccgSubSurf_getEdgeCrease(CCGEdge *e)
{
  return e->crease;
}
 
/* Face accessors */
 
CCGFaceHDL ccgSubSurf_getFaceFaceHandle(CCGFace *f)
{
  return f->fHDL;
}
int ccgSubSurf_getFaceAge(CCGSubSurf *ss, CCGFace *f)
{
  if (ss->useAgeCounts) {
    byte *user_data = static_cast<byte *>(ccgSubSurf_getFaceUserData(ss, f));
    return ss->currentAge - *((int *)&user_data[ss->faceUserAgeOffset]);
  }
  return 0;
}
void *ccgSubSurf_getFaceUserData(CCGSubSurf *ss, CCGFace *f)
{
  int maxGridSize = ccg_gridsize(ss->subdivLevels);
  return FACE_getCenterData(f) +
         ss->meshIFC.vertDataSize *
             (1 + f->numVerts * maxGridSize + f->numVerts * maxGridSize * maxGridSize);
}
int ccgSubSurf_getFaceNumVerts(CCGFace *f)
{
  return f->numVerts;
}
CCGVert *ccgSubSurf_getFaceVert(CCGFace *f, int index)
{
  if (index < 0 || index >= f->numVerts) {
    return nullptr;
  }
  return FACE_getVerts(f)[index];
}
CCGEdge *ccgSubSurf_getFaceEdge(CCGFace *f, int index)
{
  if (index < 0 || index >= f->numVerts) {
    return nullptr;
  }
  return FACE_getEdges(f)[index];
}
int ccgSubSurf_getFaceEdgeIndex(CCGFace *f, CCGEdge *e)
{
  for (int i = 0; i < f->numVerts; i++) {
    if (FACE_getEdges(f)[i] == e) {
      return i;
    }
  }
  return -1;
}
void *ccgSubSurf_getFaceCenterData(CCGFace *f)
{
  return FACE_getCenterData(f);
}
void *ccgSubSurf_getFaceGridEdgeDataArray(CCGSubSurf *ss, CCGFace *f, int gridIndex)
{
  return ccgSubSurf_getFaceGridEdgeData(ss, f, gridIndex, 0);
}
void *ccgSubSurf_getFaceGridEdgeData(CCGSubSurf *ss, CCGFace *f, int gridIndex, int x)
{
  return ccg_face_getIECo(
      f, ss->subdivLevels, gridIndex, x, ss->subdivLevels, ss->meshIFC.vertDataSize);
}
void *ccgSubSurf_getFaceGridDataArray(CCGSubSurf *ss, CCGFace *f, int gridIndex)
{
  return ccgSubSurf_getFaceGridData(ss, f, gridIndex, 0, 0);
}
void *ccgSubSurf_getFaceGridData(CCGSubSurf *ss, CCGFace *f, int gridIndex, int x, int y)
{
  return ccg_face_getIFCo(
      f, ss->subdivLevels, gridIndex, x, y, ss->subdivLevels, ss->meshIFC.vertDataSize);
}
 
/*** External API iterator functions ***/
 
void ccgSubSurf_initVertIterator(CCGSubSurf *ss, CCGVertIterator *viter)
{
  ccg_ehashIterator_init(ss->vMap, viter);
}
void ccgSubSurf_initEdgeIterator(CCGSubSurf *ss, CCGEdgeIterator *eiter)
{
  ccg_ehashIterator_init(ss->eMap, eiter);
}
void ccgSubSurf_initFaceIterator(CCGSubSurf *ss, CCGFaceIterator *fiter)
{
  ccg_ehashIterator_init(ss->fMap, fiter);
}
 
CCGVert *ccgVertIterator_getCurrent(CCGVertIterator *vi)
{
  return (CCGVert *)ccg_ehashIterator_getCurrent((EHashIterator *)vi);
}
int ccgVertIterator_isStopped(CCGVertIterator *vi)
{
  return ccg_ehashIterator_isStopped((EHashIterator *)vi);
}
void ccgVertIterator_next(CCGVertIterator *vi)
{
  ccg_ehashIterator_next((EHashIterator *)vi);
}
 
CCGEdge *ccgEdgeIterator_getCurrent(CCGEdgeIterator *ei)
{
  return (CCGEdge *)ccg_ehashIterator_getCurrent((EHashIterator *)ei);
}
int ccgEdgeIterator_isStopped(CCGEdgeIterator *ei)
{
  return ccg_ehashIterator_isStopped((EHashIterator *)ei);
}
void ccgEdgeIterator_next(CCGEdgeIterator *ei)
{
  ccg_ehashIterator_next((EHashIterator *)ei);
}
 
CCGFace *ccgFaceIterator_getCurrent(CCGFaceIterator *fi)
{
  return (CCGFace *)ccg_ehashIterator_getCurrent((EHashIterator *)fi);
}
int ccgFaceIterator_isStopped(CCGFaceIterator *fi)
{
  return ccg_ehashIterator_isStopped((EHashIterator *)fi);
}
void ccgFaceIterator_next(CCGFaceIterator *fi)
{
  ccg_ehashIterator_next((EHashIterator *)fi);
}
 
/*** External API final vert/edge/face interface. ***/
 
int ccgSubSurf_getNumFinalVerts(const CCGSubSurf *ss)
{
  int edgeSize = ccg_edgesize(ss->subdivLevels);
  int gridSize = ccg_gridsize(ss->subdivLevels);
  int numFinalVerts = (ss->vMap->numEntries + ss->eMap->numEntries * (edgeSize - 2) +
                       ss->fMap->numEntries +
                       ss->numGrids * ((gridSize - 2) + ((gridSize - 2) * (gridSize - 2))));
 
  return numFinalVerts;
}
int ccgSubSurf_getNumFinalEdges(const CCGSubSurf *ss)
{
  int edgeSize = ccg_edgesize(ss->subdivLevels);
  int gridSize = ccg_gridsize(ss->subdivLevels);
  int numFinalEdges = (ss->eMap->numEntries * (edgeSize - 1) +
                       ss->numGrids * ((gridSize - 1) + 2 * ((gridSize - 2) * (gridSize - 1))));
  return numFinalEdges;
}
int ccgSubSurf_getNumFinalFaces(const CCGSubSurf *ss)
{
  int gridSize = ccg_gridsize(ss->subdivLevels);
  int numFinalFaces = ss->numGrids * ((gridSize - 1) * (gridSize - 1));
  return numFinalFaces;
}
 
/***/
 
void CCG_key(CCGKey *key, const CCGSubSurf *ss, int level)
{
  key->level = level;
 
  key->elem_size = ss->meshIFC.vertDataSize;
  key->has_normals = ss->calcVertNormals;
 
  /* if normals are present, always the last three floats of an
   * element */
  if (key->has_normals) {
    key->normal_offset = key->elem_size - sizeof(float[3]);
  }
  else {
    key->normal_offset = -1;
  }
 
  key->grid_size = ccgSubSurf_getGridLevelSize(ss, level);
  key->grid_area = key->grid_size * key->grid_size;
  key->grid_bytes = key->elem_size * key->grid_area;
 
  key->has_mask = ss->allocMask;
  if (key->has_mask) {
    key->mask_offset = ss->maskDataOffset;
  }
  else {
    key->mask_offset = -1;
  }
}
 
void CCG_key_top_level(CCGKey *key, const CCGSubSurf *ss)
{
  CCG_key(key, ss, ccgSubSurf_getSubdivisionLevels(ss));
}