vcglib/vcg/complex/algorithms/polygon_polychord_collapse.h

1312 lines
50 KiB
C++

/****************************************************************************
* VCGLib o o *
* Visual and Computer Graphics Library o o *
* _ O _ *
* Copyright(C) 2004 \/)\/ *
* Visual Computing Lab /\/| *
* ISTI - Italian National Research Council | *
* \ *
* All rights reserved. *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License (http://www.gnu.org/licenses/gpl.txt) *
* for more details. *
* *
****************************************************************************/
#ifndef POLYGON_POLYCHORD_COLLAPSE_H
#define POLYGON_POLYCHORD_COLLAPSE_H
#include <vector>
#include <list>
#include <set>
#include <algorithm>
#include <iterator>
#include <vcg/complex/complex.h>
#include <vcg/simplex/face/jumping_pos.h>
namespace vcg {
namespace tri {
/** \addtogroup trimesh */
/**
* @brief The PolychordCollapse class provides methods to semplify a quad mesh, by collapsing the polychords.
*
* This class is an implementation of a method very similar to that for mesh semplification proposed
* by Daniels et al. in "Quadrilateral mesh simplification", see http://www.cs.utah.edu/~jdaniels/research/asia2008_qms.htm
* The main function is PolychordCollapse::CollapsePolychord() which deletes all the quadrilateral faces in a polychord.
* The polychords that can be collapsed in this case are those forming a closed loop (a ring) or that start and end to
* mesh borders. A way to preserve the structure of the singularities is also provided.
* The convenient method PolychordCollapse::CollapseAllPolychords() finds and collapses all the polychords on a mesh.
* The input mesh should be polygonal, i.e. it should have the vcg::face::PolyInfo component. Even though a generic
* triangle mesh can be given, actually the class does not perform any collapsing operation since it sees only triangles,
* in fact it does not consider faux edges.
*/
template < typename PolyMeshType >
class PolychordCollapse {
public:
typedef typename PolyMeshType::CoordType CoordType;
typedef typename PolyMeshType::VertexType VertexType;
typedef typename PolyMeshType::VertexPointer VertexPointer;
typedef typename PolyMeshType::VertexIterator VertexIterator;
typedef typename PolyMeshType::FaceType FaceType;
typedef typename PolyMeshType::FacePointer FacePointer;
typedef typename PolyMeshType::FaceIterator FaceIterator;
/**
* @brief The PC_ResultCode enum codifies the result type of a polychord collapse operation.
*/
enum PC_ResultCode {
PC_SUCCESS = 0,
PC_NOTMANIF = 1,
PC_NOTQUAD = 2,
PC_NOLINKCOND = 4,
PC_SINGBOTH = 8,
PC_SELFINTERSECT = 16,
PC_VOID = 32,
PC_OTHER = 64
};
/**
* @brief The PC_Chord struct identifies a coord of a polychord passing through a quad.
*/
struct PC_Chord {
unsigned long mark;
PC_ResultCode q;
PC_Chord * prev;
PC_Chord * next;
PC_Chord() : mark(std::numeric_limits<unsigned long>::max()), q(PC_VOID), prev(NULL), next(NULL) { }
inline void Reset() {
mark = std::numeric_limits<unsigned long>::max();
q = PC_VOID;
prev = next = NULL;
}
};
/**
* @brief The PC_Chords class gives efficient access to each coord (relative to a face).
*/
class PC_Chords {
public:
/**
* @brief PC_Chords constructor.
* @note Since each face corresponds to two chords, the actual size of the vector of chords is 2*mesh.face.size().
* @param mesh
*/
PC_Chords (const PolyMeshType &mesh) : _Chords(2*mesh.face.size()), _currentChord(NULL) {
Reset(mesh);
}
/**
* @brief ResetMarks
*/
void ResetMarks() {
typename std::vector<PC_Chord>::iterator it = _Chords.begin();
for (; it != _Chords.end(); it++)
(*it).mark = std::numeric_limits<unsigned long>::max();
}
/**
* @brief Reset rearrages the container.
* @note Since each face corresponds to two chords, the actual size of the vector of chords is 2*mesh.face.size().
* @param mesh
*/
void Reset(const PolyMeshType &mesh) {
_Chords.resize(2*mesh.face.size());
for (size_t j = 0; j < _Chords.size(); j++)
_Chords[j].Reset();
_currentChord = NULL;
PC_Chord *chord = NULL;
long long j = 0;
for (size_t i = 0; i < _Chords.size(); i++) {
// set the prev
chord = NULL;
if ((long long)i-1 >= 0) {
chord = &_Chords[i-1];
if (vcg::tri::HasPerFaceFlags(mesh)) {
j = i-1;
while (j >= 0 && mesh.face[j/2].IsD())
j--;
if (j >= 0)
chord = &_Chords[j];
else
chord = NULL;
}
}
_Chords[i].prev = chord;
// set the next
chord = NULL;
if (i+1 < _Chords.size()) {
chord = &_Chords[i+1];
if (vcg::tri::HasPerFaceFlags(mesh)) {
j = i+1;
while (j < (long long)_Chords.size() && mesh.face[j/2].IsD())
j++;
if (j < (long long)_Chords.size())
chord = &_Chords[j];
else
chord = NULL;
}
}
_Chords[i].next = chord;
}
if (mesh.face.size() > 0) {
// set the current coord (first - not deleted - face)
_currentChord = &_Chords[0];
if (vcg::tri::HasPerFaceFlags(mesh) && mesh.face[0].IsD())
_currentChord = _currentChord->next;
}
}
/**
* @brief operator [], given a face index and an offset, it returns (a reference to) its corresponding PC_Chord.
* @param face_edge A std::pair<size_t, unsigned char>(face_index, offset). The offset should be 0 or 1.
* @return A reference to the corresponding PC_Chord.
*/
inline PC_Chord & operator[] (const std::pair<size_t, unsigned char> &face_edge) {
assert(face_edge.first >= 0 && 2*face_edge.first+face_edge.second < _Chords.size());
return _Chords[2*face_edge.first + face_edge.second];
}
/**
* @brief operator [], given a face index and an offset, it returns (a const reference to) its corresponding PC_Chord.
* @param face_edge A std::pair<size_t, unsigned char>(face_index, offset). The offset should be 0 or 1.
* @return A reference to the corresponding PC_Chord.
*/
inline const PC_Chord & operator[] (const std::pair<size_t, unsigned char> &face_edge) const {
assert(face_edge.first >= 0 && 2*face_edge.first+face_edge.second < _Chords.size());
return _Chords[2*face_edge.first + face_edge.second];
}
/**
* @brief operator [], given a coord, it returns its corresponding face index and edge.
* @param coord The coord pointer.
* @return A std::pair <size_t, unsigned char>(face_index, offset) with offset being 0 or 1.
*/
inline std::pair<size_t, unsigned char> operator[] (PC_Chord const * const coord) {
assert(coord >= &_Chords[0] && coord < &_Chords[0]+_Chords.size());
return std::pair<size_t, unsigned char>((coord - &_Chords[0])/2, (coord - &_Chords[0])%2);
}
/**
* @brief UpdateCoord updates the coord information and links.
* @param coord The coord to update.
* @param mark The mark of the polychord.
* @param resultCode The code for the type of the polychord.
*/
inline void UpdateCoord (PC_Chord &coord, const unsigned long mark, const PC_ResultCode resultCode) {
// update prev and next
if (coord.q == PC_VOID) {
if (coord.prev != NULL && &coord != _currentChord)
coord.prev->next = coord.next;
if (coord.next != NULL && &coord != _currentChord)
coord.next->prev = coord.prev;
coord.mark = mark;
}
coord.q = resultCode;
}
/**
* @brief Next, if it's not at the end, it goes to the next coord.
*/
inline void Next () {
if (_currentChord != NULL)
_currentChord = _currentChord->next;
}
/**
* @brief GetCurrent returns the current FaceType pointer and edge.
* @param face_edge A std::pair where to store the FaceType pointer and the edge index.
*/
inline void GetCurrent (std::pair<size_t, unsigned char> &face_edge) {
if (_currentChord != NULL) {
face_edge.first = (_currentChord - &_Chords[0])/2;
face_edge.second = (_currentChord - &_Chords[0])%2;
} else {
face_edge.first = std::numeric_limits<size_t>::max();
face_edge.second = 0;
}
}
/**
* @brief End says if an end has been reached.
* @return true if an end has been reached, false otherwise.
*/
inline bool End () {
return _currentChord == NULL;
}
private:
std::vector<PC_Chord> _Chords;
PC_Chord *_currentChord;
};
/**
* @brief The LinkCondition class provides a tool to check if a polychord satisfies the link conditions.
*/
class LinkConditions {
private:
typedef long int LCVertexIndex;
typedef std::set<LCVertexIndex> LCVertexStar; // define the star of a vertex
typedef long int LCEdgeIndex;
typedef std::set<LCEdgeIndex> LCEdgeStar; // define the set of edges whose star involves a vertex
/**
* @brief The LCVertex struct represents a vertex for the Link Conditions.
*/
struct LCVertex {
LCVertexStar star; // vertex star
LCEdgeStar edges; // list of edges whose star involves this vertex
LCVertex(){} // default constructor
LCVertex(const LCVertex &lcVertex) { // copy constructor
star = lcVertex.star;
edges = lcVertex.edges;
}
LCVertex & operator=(const LCVertex &lcVertex) { // assignment operator
star = lcVertex.star;
edges = lcVertex.edges;
return *this;
}
void reset() { star.clear(); edges.clear(); } // reset
};
/**
* @brief The LCEdge struct represents an edge for the Link Conditions.
*/
struct LCEdge {
LCVertexIndex v1, v2; // endpoints
LCVertexStar star; // edge star
LCEdge() {v1 = v2 = -1;} // default contructor
LCEdge(const LCEdge &lcEdge) { // copy constructor
v1 = lcEdge.v1;
v2 = lcEdge.v2;
star = lcEdge.star;
}
LCEdge & operator=(const LCEdge &lcEdge) { // assignment operator
v1 = lcEdge.v1;
v2 = lcEdge.v2;
star = lcEdge.star;
return *this;
}
void reset() { // reset
v1 = -1;
v2 = -1;
star.clear();
}
};
public:
/**
* @brief LinkCondition constructor.
* @param size The number of vertices of the mesh.
*/
LinkConditions (const size_t size) : _lcVertices(size) { }
/**
* @brief Resize just resets the size of the container.
* @param size
*/
inline void Resize(const size_t size) {
_lcVertices.resize(size);
LC_ResetStars();
}
/**
* @brief CheckLinkConditions checks if collapsing the polychord starting from startPos
* satisfies the link conditions.
* @warning The polychord starts from startPos and ends to itself (if it's a loop) or to a border. In the latter case,
* call this method starting from the opposite border of the strip of quads.
* @param mesh The mesh for getting the vertex index.
* @param startPos The starting position of the polychord.
* @return true if satisfied, false otherwise.
*/
bool CheckLinkConditions (const PolyMeshType &mesh, const vcg::face::Pos<FaceType> &startPos) {
assert(!startPos.IsNull());
assert(mesh.vert.size() == _lcVertices.size());
std::vector<LCEdge> lcEdges;
LCVertexStar intersection;
// reset the stars
LC_ResetStars();
// compute the stars
LC_computeStars(mesh, startPos, lcEdges);
// for each edge e = (v1,v2)
// if intersection( star(v1) , star(v2) ) == star(e)
// then collapse e
// else
// return false (i.e. link conditions not satisfied)
for (size_t e = 0; e < lcEdges.size(); e++) {
// compute the intersetion
intersection.clear();
std::set_intersection(_lcVertices[lcEdges[e].v1].star.begin(), _lcVertices[lcEdges[e].v1].star.end(),
_lcVertices[lcEdges[e].v2].star.begin(), _lcVertices[lcEdges[e].v2].star.end(),
std::inserter(intersection, intersection.end()));
// if intersection( star(v1) , star(v2) ) != star(e) then return false
if (intersection != lcEdges[e].star)
return false;
// else simulate the collapse
LC_SimulateEdgeCollapse(lcEdges, e);
}
// at this point all collapses are possible, thus return true
return true;
}
private:
/**
* @brief LC_ResetStars resets the stars on a polychord.
*/
void LC_ResetStars() {
for (size_t v = 0; v < _lcVertices.size(); v++)
_lcVertices[v].reset();
}
/**
* @brief LC_computeStars computes the stars of edges and vertices of the polychord from the starting pos
* either to itself (if it's a loop) or to the border edge.
* @param mesh The mesh for getting the vertex index.
* @param startPos Starting position.
* @param lcEdges Vector of edge stars.
*/
void LC_computeStars (const PolyMeshType &mesh, const vcg::face::Pos<FaceType> &startPos, std::vector<LCEdge> &lcEdges) {
assert(!startPos.IsNull());
assert(mesh.vert.size() == _lcVertices.size());
vcg::face::Pos<FaceType> runPos = startPos;
vcg::face::JumpingPos<FaceType> vStarPos;
vcg::face::Pos<FaceType> eStarPos;
LCEdgeIndex edgeInd = -1;
size_t nEdges = 0;
// count how many edges
do {
nEdges++;
// go on the next edge
runPos.FlipE();
runPos.FlipV();
runPos.FlipE();
runPos.FlipF();
} while (runPos != startPos && !runPos.IsBorder());
if (runPos.IsBorder())
nEdges++;
// resize the vector of edges
lcEdges.resize(nEdges);
for (size_t e = 0; e < nEdges; e++)
lcEdges[e].reset();
/// compute the star of all the vertices and edges seen from the polychord
runPos = startPos;
do {
// access the next lcedge
edgeInd++;
// set lcvertices references
lcEdges[edgeInd].v1 = vcg::tri::Index(mesh, runPos.V());
lcEdges[edgeInd].v2 = vcg::tri::Index(mesh, runPos.VFlip());
// add this edge to its vertices edge-stars
_lcVertices[lcEdges[edgeInd].v1].edges.insert(edgeInd);
_lcVertices[lcEdges[edgeInd].v2].edges.insert(edgeInd);
// compute the star of this edge
lcEdges[edgeInd].star.insert(lcEdges[edgeInd].v1); // its endpoints, clearly
lcEdges[edgeInd].star.insert(lcEdges[edgeInd].v2); // its endpoints, clearly
// navigate over the other vertices of this facet
eStarPos = runPos;
eStarPos.FlipE();
eStarPos.FlipV();
while (eStarPos.V() != runPos.VFlip()) {
// add current vertex to the star of this edge
lcEdges[edgeInd].star.insert(vcg::tri::Index(mesh, eStarPos.V()));
// add this edge to the edge-star of the current vertex
_lcVertices[vcg::tri::Index(mesh, eStarPos.V())].edges.insert(edgeInd);
// go on
eStarPos.FlipE();
eStarPos.FlipV();
}
// go on the opposite facet
if (!runPos.IsBorder()) {
eStarPos = runPos;
eStarPos.FlipF();
eStarPos.FlipE();
eStarPos.FlipV();
while (eStarPos.V() != runPos.VFlip()) {
// add current vertex to the star of this edge
lcEdges[edgeInd].star.insert(vcg::tri::Index(mesh, eStarPos.V()));
// add this edge to the edge-star of the current vertex
_lcVertices[vcg::tri::Index(mesh, eStarPos.V())].edges.insert(edgeInd);
// go on
eStarPos.FlipE();
eStarPos.FlipV();
}
}
// compute the star of vertex v2
runPos.FlipV();
vStarPos.Set(runPos.F(), runPos.E(), runPos.V());
// v2 is in its star
_lcVertices[vcg::tri::Index(mesh, vStarPos.V())].star.insert(vcg::tri::Index(mesh, vStarPos.V()));
do {
vStarPos.FlipV();
vStarPos.FlipE();
while (vStarPos.V() != runPos.V()) {
// add the current vertex to the v2 star
_lcVertices[vcg::tri::Index(mesh, runPos.V())].star.insert(vcg::tri::Index(mesh, vStarPos.V()));
// add v2 to the star of the current vertex
_lcVertices[vcg::tri::Index(mesh, vStarPos.V())].star.insert(vcg::tri::Index(mesh, runPos.V()));
vStarPos.FlipV();
vStarPos.FlipE();
}
vStarPos.NextFE();
} while (vStarPos != runPos);
// compute the star of vertex v1
runPos.FlipV();
vStarPos.Set(runPos.F(), runPos.E(), runPos.V());
// v1 is in its star
_lcVertices[vcg::tri::Index(mesh, vStarPos.V())].star.insert(vcg::tri::Index(mesh, vStarPos.V()));
do {
vStarPos.FlipV();
vStarPos.FlipE();
while (vStarPos.V() != runPos.V()) {
// add the current vertex to the v2 star
_lcVertices[vcg::tri::Index(mesh, runPos.V())].star.insert(vcg::tri::Index(mesh, vStarPos.V()));
// add v2 to the star of the current vertex
_lcVertices[vcg::tri::Index(mesh, vStarPos.V())].star.insert(vcg::tri::Index(mesh, runPos.V()));
vStarPos.FlipV();
vStarPos.FlipE();
}
vStarPos.NextFE();
} while (vStarPos != runPos);
// when arrive to a border, stop
if (runPos != startPos && runPos.IsBorder())
break;
// go on the next edge
runPos.FlipE();
runPos.FlipV();
runPos.FlipE();
runPos.FlipF();
} while (runPos != startPos);
// check if the starting pos or the border has been reached
assert(runPos == startPos || runPos.IsBorder());
}
/**
* @brief LC_SimulateEdgeCollapse simulates an edge collapse by updating the stars involved.
* @param lcEdges The vector of edges.
* @param edgeInd The in dex of the edge to collapse.
*/
void LC_SimulateEdgeCollapse (std::vector<LCEdge> &lcEdges, const LCEdgeIndex edgeInd) {
// let v1 and v2 be the two end points
LCVertexIndex v1 = lcEdges[edgeInd].v1;
LCVertexIndex v2 = lcEdges[edgeInd].v2;
LCVertexIndex v = -1;
/// v2 merges into v1:
// star(v1) = star(v1) U star(v2)
_lcVertices[v1].star.insert(_lcVertices[v2].star.begin(), _lcVertices[v2].star.end());
_lcVertices[v1].star.erase(v2); // remove v2 from v1-star
_lcVertices[v2].star.erase(v1); // remove v1 from v2-star
// foreach v | v2 \in star(v) [i.e. v \in star(v2)]
// star(v) = star(v) U {v1} \ {v2}
for (typename LCVertexStar::iterator vIt = _lcVertices[v2].star.begin(); vIt != _lcVertices[v2].star.end(); vIt++) {
v = *vIt;
if (v == v2) // skip v2 itself
continue;
_lcVertices[v].star.insert(v1);
_lcVertices[v].star.erase(v2);
}
/// update the star of the edges which include v1 and v2 in their star
// foreach e | v1 \in star(e) ^ v2 \in star(e)
// star(e) = star(e) \ {v1,v2} U {v1}
for (typename LCEdgeStar::iterator eIt = _lcVertices[v1].edges.begin(); eIt != _lcVertices[v1].edges.end(); eIt++)
lcEdges[*eIt].star.erase(v2);
for (typename LCEdgeStar::iterator eIt = _lcVertices[v2].edges.begin(); eIt != _lcVertices[v2].edges.end(); eIt++) {
lcEdges[*eIt].star.erase(v2);
lcEdges[*eIt].star.insert(v1);
}
}
/**
* @brief _lcVertices is a vector of vertex stars for the link conditions.
*/
std::vector<LCVertex> _lcVertices;
};
// PolychordCollapse's methods begin here::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
/**
* @brief CollapsePolychord performs all checks and then collapses the polychord.
*
* @warning This function deletes faces and vertices by calling
* vcg::tri::Allocator<PolyMeshType>::DeleteFace() and
* vcg::tri::Allocator<PolyMeshType>::DeleteVertex().
* The object PC_Chords chords is used to track the polychords, and it has got
* a size proportional to that of the mesh face container. If you actually
* delete faces and vertices by calling vcg::tri::Allocator<PolyMeshType>::CompactFaceVector()
* and vcg::tri::Allocator<PolyMeshType>::CompactVertexVector() after this function,
* object PC_Chords chords then is not valid any more, so you MUST rearrange it
* by calling PC_Chords.Reset(). For the same reason, you MUST rearrange LinkConditions linkConditions
* by calling LinkConditions.Resize().
* However, for efficiency, you SHOULD compact vertex and face containers at the end of all your
* polychord collapsing operations, without having to rearrange chords and linkConditions.
* The function CollapseAllPolychords() does this for you.
*
* @note Vertex flags, face flags, FF adjacency and FV adjacency are required. Not anything else.
* Such components are automatically updated here. If the mesh has other components that may be
* affected by this editing, you should update them later by yourself.
*
* @param mesh The polygonal mesh used for getting the face index and deleting the faces
* (it SHOULD have the vcg::face::PolyInfo component).
* @param pos Position of the polychord.
* @param mark Mark for the current polychord.
* @param chords Vector of chords.
* @param linkConditions Link conditions checker.
* @param checkSing true if singularities on both sides are not allowed.
* @return A PC_ResultCode resulting from checks or PC_SUCCESS if the collapse has been performed.
*/
static PC_ResultCode CollapsePolychord (PolyMeshType &mesh,
const vcg::face::Pos<FaceType> &pos,
const unsigned long mark,
PC_Chords &chords,
LinkConditions &linkConditions,
const bool checkSing = true) {
vcg::tri::RequirePerVertexFlags(mesh);
vcg::tri::RequirePerFaceFlags(mesh);
if (mesh.IsEmpty())
return PC_VOID;
if (pos.IsNull())
return PC_VOID;
vcg::face::Pos<FaceType> tempPos, startPos;
// check if the sequence of facets is a polychord and find the starting coord
PC_ResultCode resultCode = CheckPolychordFindStartPosition(pos, startPos, checkSing);
// if not successful, visit the sequence for marking it and return
if (resultCode != PC_SUCCESS) {
// if not manifold, visit the entire polychord ending on the non-manifold edge
if (resultCode == PC_NOTMANIF) {
tempPos = pos;
VisitPolychord(mesh, tempPos, chords, mark, resultCode);
if (tempPos.IsManifold() && !tempPos.IsBorder()) {
tempPos.FlipF();
VisitPolychord(mesh, tempPos, chords, mark, resultCode);
}
return resultCode;
}
// if not quad, visit all the polychords passing through this coord
if (resultCode == PC_NOTQUAD) {
tempPos = startPos;
do {
if (!tempPos.IsBorder()) {
tempPos.FlipF();
VisitPolychord(mesh, tempPos, chords, mark, resultCode);
tempPos.FlipF();
}
tempPos.FlipV();
tempPos.FlipE();
} while (tempPos != startPos);
}
VisitPolychord(mesh, startPos, chords, mark, resultCode);
return resultCode;
}
// check if the link conditions are satisfied
bool lc = linkConditions.CheckLinkConditions(mesh, startPos);
// if not satisfied, visit the sequence for marking it and return
if (!lc) {
VisitPolychord(mesh, startPos, chords, mark, PC_NOLINKCOND);
return PC_NOLINKCOND;
}
// check if the polychord does not intersect itself
bool si = IsPolychordSelfIntersecting(mesh, startPos, chords, mark);
// if it self-intersects, visit the polychord for marking it and return
if (si) {
VisitPolychord(mesh, startPos, chords, mark, PC_SELFINTERSECT);
return PC_SELFINTERSECT;
}
// at this point the polychord is collapsable, visit it for marking
VisitPolychord(mesh, startPos, chords, mark, PC_SUCCESS);
// now collapse
CoordType point;
int valenceA = 0, valenceB = 0;
vcg::face::Pos<FaceType> runPos = startPos;
vcg::face::JumpingPos<FaceType> tmpPos;
bool onSideA = false, onSideB = false;
vcg::face::Pos<FaceType> sideA, sideB;
typedef std::queue<VertexPointer *> FacesVertex;
typedef std::pair<VertexPointer, FacesVertex> FacesVertexPair;
typedef std::queue<FacesVertexPair> FacesVertexPairQueue;
FacesVertexPairQueue vQueue;
typedef std::pair<FacePointer *, FacePointer> FFpPair;
typedef std::pair<char *, char> FFiPair;
typedef std::pair<FFpPair, FFiPair> FFPair;
typedef std::queue<FFPair> FFQueue;
FFQueue ffQueue;
std::queue<VertexPointer> verticesToDeleteQueue;
std::queue<FacePointer> facesToDeleteQueue;
if (checkSing) {
do {
runPos.FlipV();
valenceB = runPos.NumberOfIncidentVertices();
tmpPos.Set(runPos.F(), runPos.E(), runPos.V());
if (tmpPos.FindBorder())
valenceB++;
runPos.FlipV();
valenceA = runPos.NumberOfIncidentVertices();
tmpPos.Set(runPos.F(), runPos.E(), runPos.V());
if (tmpPos.FindBorder())
valenceA++;
if (valenceA != 4)
onSideA = true;
if (valenceB != 4)
onSideB = true;
assert(!onSideA || !onSideB);
if (runPos != startPos && runPos.IsBorder())
break;
// go on next edge/face
runPos.FlipE();
runPos.FlipV();
runPos.FlipE();
runPos.FlipF();
} while (runPos != startPos);
}
runPos = startPos;
do {
// compute new vertex
point = (runPos.V()->P() + runPos.VFlip()->P()) / 2.f;
if (checkSing) {
if (onSideA)
point = runPos.V()->P();
if (onSideB)
point = runPos.VFlip()->P();
}
runPos.V()->P() = point;
// list the vertex pointer of the faces on the other side to be updated
vQueue.push(FacesVertexPair());
vQueue.back().first = runPos.V();
tmpPos.Set(runPos.F(), runPos.E(), runPos.V());
tmpPos.FlipV();
tmpPos.NextFE(); // go to next face
while (tmpPos.F() != runPos.F()) {
if (tmpPos.F() != runPos.FFlip())
vQueue.back().second.push(&tmpPos.F()->V(tmpPos.VInd()));
tmpPos.NextFE(); // go to next face
}
// enqueue to delete the other vertex
verticesToDeleteQueue.push(runPos.VFlip());
// list the adjacencies
sideA = runPos;
sideA.FlipE();
sideA.FlipF();
sideB = runPos;
sideB.FlipV();
sideB.FlipE();
sideB.FlipF();
// first side
if (!sideA.IsBorder()) {
ffQueue.push(FFPair(FFpPair(),FFiPair()));
ffQueue.back().first.first = &sideA.F()->FFp(sideA.E());
ffQueue.back().second.first = &sideA.F()->FFi(sideA.E());
if (!sideB.IsBorder()) {
ffQueue.back().first.second = sideB.F();
ffQueue.back().second.second = sideB.E();
} else {
ffQueue.back().first.second = sideA.F();
ffQueue.back().second.second = sideA.E();
}
}
// second side
if (!sideB.IsBorder()) {
ffQueue.push(FFPair(FFpPair(),FFiPair()));
ffQueue.back().first.first = &sideB.F()->FFp(sideB.E());
ffQueue.back().second.first = &sideB.F()->FFi(sideB.E());
if (!sideA.IsBorder()) {
ffQueue.back().first.second = sideA.F();
ffQueue.back().second.second = sideA.E();
} else {
ffQueue.back().first.second = sideB.F();
ffQueue.back().second.second = sideB.E();
}
}
// enqueue to delete the face
facesToDeleteQueue.push(runPos.F());
// go on next edge/face
runPos.FlipE();
runPos.FlipV();
runPos.FlipE();
runPos.FlipF();
} while (runPos != startPos && !runPos.IsBorder());
assert(runPos == startPos || vcg::face::IsBorder(*startPos.F(),startPos.E()));
if (runPos.IsBorder()) {
// compute new vertex on the last (border) edge
point = (runPos.V()->P() + runPos.VFlip()->P()) / 2.f;
if (checkSing) {
if (onSideA)
point = runPos.V()->P();
if (onSideB)
point = runPos.VFlip()->P();
}
runPos.V()->P() = point;
// list the vertex pointer of the faces on the other side to be updated
vQueue.push(FacesVertexPair());
vQueue.back().first = runPos.V();
tmpPos.Set(runPos.F(), runPos.E(), runPos.V());
tmpPos.FlipV();
tmpPos.NextFE(); // go to next face
while (tmpPos.F() != runPos.F()) {
vQueue.back().second.push(&tmpPos.F()->V(tmpPos.VInd()));
tmpPos.NextFE();
}
// enqueue to delete the other vertex
verticesToDeleteQueue.push(runPos.VFlip());
}
// update vertices
while (!vQueue.empty()) {
while (!vQueue.front().second.empty()) {
*vQueue.front().second.front() = vQueue.front().first;
vQueue.front().second.pop();
}
vQueue.pop();
}
// update adjacencies
while (!ffQueue.empty()) {
*ffQueue.front().first.first = ffQueue.front().first.second;
*ffQueue.front().second.first = ffQueue.front().second.second;
ffQueue.pop();
}
// delete faces
while (!facesToDeleteQueue.empty()) {
vcg::tri::Allocator<PolyMeshType>::DeleteFace(mesh, *facesToDeleteQueue.front());
facesToDeleteQueue.pop();
}
// delete vertices
while (!verticesToDeleteQueue.empty()) {
vcg::tri::Allocator<PolyMeshType>::DeleteVertex(mesh, *verticesToDeleteQueue.front());
verticesToDeleteQueue.pop();
}
return PC_SUCCESS;
}
/**
* @brief CollapseAllPolychords finds and collapses all the polychords.
* @param mesh The input polygonal mesh (it SHOULD have the vcg::face::PolyInfo component).
* @param checkSing true if singularities on both sides of a polychord are not allowed.
*/
static void CollapseAllPolychords (PolyMeshType &mesh, const bool checkSing = true) {
vcg::tri::RequireFFAdjacency(mesh);
if (mesh.IsEmpty())
return;
vcg::face::Pos<FaceType> pos;
PC_ResultCode resultCode;
std::pair<size_t, unsigned char> face_edge;
// construct the link conditions checker
LinkConditions linkConditions(mesh.vert.size());
// construct the vector of chords
PC_Chords chords(mesh);
unsigned long mark = 0;
// iterate over all the chords
while (!chords.End()) {
// get the current coord
chords.GetCurrent(face_edge);
// construct a pos on the face and edge of the current coord
pos.Set(&mesh.face[face_edge.first], face_edge.second, mesh.face[face_edge.first].V(face_edge.second));
// (try to) collapse the polychord
resultCode = CollapsePolychord(mesh, pos, mark, chords, linkConditions, checkSing);
// go to the next coord
chords.Next();
// increment the mark
mark++;
if (mark == std::numeric_limits<unsigned long>::max()) {
chords.ResetMarks();
mark = 0;
}
}
}
/**
* @brief SplitPolychord splits a polychord into n polychords by inserting all the needed faces.
* @param mesh is the input polygonal mesh.
* @param pos is a position into the polychord (not necessarily the starting border).
* @param n is the number of polychords to replace the input one.
* @param facesToUpdate is a vector of face pointers to be updated after re-allocation.
* @param verticesToUpdate is a vector of vertex pointers to be updated after re-allocation.
*/
static void SplitPolychord (PolyMeshType &mesh, const vcg::face::Pos<FaceType> &pos, const size_t n,
std::vector<FacePointer *> &facesToUpdate = std::vector<FacePointer *>(),
std::vector<VertexPointer *> &verticesToUpdate = std::vector<VertexPointer *>()) {
if (mesh.IsEmpty())
return;
if (pos.IsNull())
return;
if (n <= 1)
return;
// find the real starting position (is the polychord a strip or a ring?) and count how many faces there are
size_t fn = 0;
bool polyBorderFound = false;
vcg::face::Pos<FaceType> startPos = pos;
do {
// check if all faces are 4-sided
if (startPos.F()->VN() != 4)
return;
// check manifoldness
if (IsVertexAdjacentToAnyNonManifoldEdge(startPos))
return;
// increase the number of faces
fn++;
// go on the opposite edge
startPos.FlipE();
startPos.FlipV();
startPos.FlipE();
// if the first border has been reached, go on the other direction to find the other border
if (!polyBorderFound && startPos != pos && startPos.IsBorder()) {
// check manifoldness
if (IsVertexAdjacentToAnyNonManifoldEdge(startPos))
return;
startPos = pos;
polyBorderFound = true;
}
// if the other border has been reached, stop
if (polyBorderFound && startPos.IsBorder()) {
// check manifoldness
if (IsVertexAdjacentToAnyNonManifoldEdge(startPos))
return;
break;
}
// check manifoldness
if (!startPos.IsManifold())
return;
// go onto the next face
startPos.FlipF();
} while (startPos != pos);
// as every face has an orientation, ensure that the new polychords are inserted on the right of the starting pos
startPos.FlipE();
int e = startPos.E();
startPos.FlipE();
if (startPos.F()->Next(startPos.E()) != e)
startPos.FlipV();
// compute the number of faces and vertices that must be added to the mesh in order to insert the new polychords
size_t FN = fn * (n - 1);
size_t VN = FN;
if (startPos.IsBorder())
VN += n - 1;
// add the starting position's face and vertex pointers to the list of things to update after re-allocation
facesToUpdate.push_back(&startPos.F());
verticesToUpdate.push_back(&startPos.V());
// add faces to the mesh
FaceIterator firstAddedFaceIt = vcg::tri::Allocator<PolyMeshType>::AddFaces(mesh, FN, facesToUpdate);
// add vertices to the mesh
VertexIterator firstAddedVertexIt = vcg::tri::Allocator<PolyMeshType>::AddVertices(mesh, VN, verticesToUpdate);
// delete the added starting position's face and vertex pointers
facesToUpdate.pop_back();
verticesToUpdate.pop_back();
// allocate and initialize 4 vertices and ffAdj for each new face
for (FaceIterator fIt = firstAddedFaceIt; fIt != mesh.face.end(); fIt++) {
fIt->Alloc(4);
for (size_t j = 0; j < 4; j++) {
fIt->FFp(j) = &*fIt;
fIt->FFi(j) = j;
}
}
// some variables
size_t ln = fn;
if (startPos.IsBorder())
ln++;
FacePointer lf = NULL; // face on the left to the current one
int lfre = 0; // right edge of lf
VertexPointer * lfbrV = NULL; // address of the bottom-right vertex pointer of lf
VertexPointer * lftrV = NULL; // address of the top-right vertex pointer of lf
CoordType lvP;
CoordType svP;
typedef std::pair<FacePointer,int> FaceEdge;
typedef std::pair<FaceEdge,FaceEdge> FaceFaceAdj;
typedef std::pair<VertexPointer *,VertexPointer> FaceVertexAdj;
std::queue<FaceFaceAdj> ffAdjQueue; // face-to-face adjacency queue
std::queue<FaceVertexAdj> fvAdjQueue; // face-to-vertex adjacency queue
bool currentFaceBottomIsBorder = false;
// map faces to lines' number
vcg::face::Pos<FaceType> runPos = startPos;
std::map<FacePointer,size_t> faceLineMap;
typename std::map<FacePointer,size_t>::iterator faceLineIt;
for (size_t i = 0; i < fn; i++) {
faceLineMap.insert(std::pair<FacePointer,size_t>(runPos.F(), i));
runPos.FlipE();
runPos.FlipV();
runPos.FlipE();
runPos.FlipF();
}
// scan the polychord and add adj into queues
runPos = startPos;
for (size_t i = 0; i < fn; i++) {
// store links to the current left face
lf = runPos.F();
currentFaceBottomIsBorder = runPos.IsBorder();
lvP = runPos.VFlip()->P();
svP = (runPos.V()->P() - lvP) / n;
runPos.FlipE();
lfre = runPos.E();
lfbrV = &runPos.F()->V(runPos.VInd());
runPos.FlipV();
lftrV = &runPos.F()->V(runPos.VInd());
// set the current line's last face's right ff adjacency
if (!runPos.IsBorder()) {
faceLineIt = faceLineMap.find(runPos.FFlip());
if (faceLineIt != faceLineMap.end()) // a 2-valence vertex caused the polychord to blend and touch itself
ffAdjQueue.push(FaceFaceAdj(FaceEdge(&*(firstAddedFaceIt + (i+1)*(n-1) - 1), 1), FaceEdge(&*(firstAddedFaceIt + (faceLineIt->second+1)*(n-1) - 1), 1)));
else
ffAdjQueue.push(FaceFaceAdj(FaceEdge(&*(firstAddedFaceIt + (i+1)*(n-1) - 1), 1), FaceEdge(runPos.FFlip(), runPos.F()->FFi(runPos.E()))));
}
// set the current line's last face's bottom right vertex's coords
(firstAddedVertexIt + (i+1)*(n-1) - 1)->P() = lvP + svP * (n - 1);
// set the current line's last face's bottom right vertex
fvAdjQueue.push(FaceVertexAdj(&(firstAddedFaceIt + (i+1)*(n-1) - 1)->V(1), runPos.VFlip()));
// set the current face's top left vertex
fvAdjQueue.push(FaceVertexAdj(&(firstAddedFaceIt + (i+1)*(n-1) - 1)->V(2), runPos.V()));
runPos.FlipE();
if (!runPos.IsBorder())
runPos.FlipF();
else
for (size_t j = 0; j < n-1; j++)
// set the current face's bottom right vertex's coords
(firstAddedVertexIt + (i+1)*(n-1) + j)->P() = runPos.VFlip()->P() +
(runPos.V()->P() - runPos.VFlip()->P()) / n * (j+1);
// run horizontally on the current line of the grid
for (size_t j = 0; j < n-1; j++) {
// set the current face's left ff adj
ffAdjQueue.push(FaceFaceAdj(FaceEdge(lf, lfre), FaceEdge(&*(firstAddedFaceIt + i*(n-1) + j), 3)));
// set the current face's bottom ff adjacency
if (!currentFaceBottomIsBorder)
ffAdjQueue.push(FaceFaceAdj(FaceEdge(&*(firstAddedFaceIt + ((i+fn-1)%fn)*(n-1) + j), 2), FaceEdge(&*(firstAddedFaceIt + i*(n-1) + j), 0)));
// set the current face's bottom right vertex's coords
(firstAddedVertexIt + i*(n-1) + j)->P() = lvP + svP * (j+1);
// set the left face's bottom right vertex
fvAdjQueue.push(FaceVertexAdj(lfbrV, &*(firstAddedVertexIt + i*(n-1) + j)));
// set the current face's bottom left vertex
fvAdjQueue.push(FaceVertexAdj(&(firstAddedFaceIt + i*(n-1) + j)->V(0), &*(firstAddedVertexIt + i*(n-1) + j)));
// set the left face's top right vertex
fvAdjQueue.push(FaceVertexAdj(lftrV, &*(firstAddedVertexIt + ((i+1)%ln)*(n-1) + j)));
// set the current face's top left vertex
fvAdjQueue.push(FaceVertexAdj(&(firstAddedFaceIt + i*(n-1) + j)->V(3), &*(firstAddedVertexIt + ((i+1)%ln)*(n-1) + j)));
// update temporary variables
lf = &*(firstAddedFaceIt + i*(n-1) + j);
lfre = 1;
lfbrV = &(firstAddedFaceIt + i*(n-1) + j)->V(1);
lftrV = &(firstAddedFaceIt + i*(n-1) + j)->V(2);
}
}
// now apply ff adj changes
while (!ffAdjQueue.empty()) {
// the left/bottom face links to the right/top face
ffAdjQueue.front().first.first->FFp(ffAdjQueue.front().first.second) = ffAdjQueue.front().second.first;
ffAdjQueue.front().first.first->FFi(ffAdjQueue.front().first.second) = ffAdjQueue.front().second.second;
// the right/top face links to the left/bottom face
ffAdjQueue.front().second.first->FFp(ffAdjQueue.front().second.second) = ffAdjQueue.front().first.first;
ffAdjQueue.front().second.first->FFi(ffAdjQueue.front().second.second) = ffAdjQueue.front().first.second;
// pop from queue
ffAdjQueue.pop();
}
// and apply fv adj changes
while (!fvAdjQueue.empty()) {
*fvAdjQueue.front().first = fvAdjQueue.front().second;
fvAdjQueue.pop();
}
}
/**
* @brief CheckPolychordFindStartPosition checks if it's a collapsable polychord.
* @param pos Input The starting position.
* @param startPos Output the new starting position (in case of borders).
* @param checkSing true if singularities on both sides are not allowed.
* @return PC_SUCCESS if it's a collapsable polychord, otherwise the code for the cause (startPos is on it).
*/
static PC_ResultCode CheckPolychordFindStartPosition (const vcg::face::Pos<FaceType> &pos,
vcg::face::Pos<FaceType> &startPos,
const bool checkSing = true) {
assert(!pos.IsNull());
int valence = 0;
bool singSideA = false, singSideB = false;
bool borderSideA = false, borderSideB = false;
bool polyBorderFound = false;
vcg::face::JumpingPos<FaceType> jmpPos;
startPos = pos;
do {
// check if it is a quad
if (startPos.F()->VN() != 4)
return PC_NOTQUAD;
// check manifoldness
if (IsVertexAdjacentToAnyNonManifoldEdge(startPos))
return PC_NOTMANIF;
startPos.FlipV();
if (IsVertexAdjacentToAnyNonManifoldEdge(startPos))
return PC_NOTMANIF;
startPos.FlipV();
// check if side A is on border
startPos.FlipE();
if (startPos.IsBorder())
borderSideA = true;
startPos.FlipE();
// check if side B is on border
startPos.FlipV();
startPos.FlipE();
if (startPos.IsBorder())
borderSideB = true;
startPos.FlipE();
startPos.FlipV();
// check if singularities are not in both sides
if (checkSing) {
// compute the valence of the vertex on side B
startPos.FlipV();
valence = startPos.NumberOfIncidentVertices();
// if the vertex is on border increment its valence by 1 (virtually connect it to a dummy vertex)
jmpPos.Set(startPos.F(), startPos.E(), startPos.V());
if (jmpPos.FindBorder())
valence++;
if (valence != 4)
singSideB = true;
// a 2-valence internl vertex cause a polychord to touch itself, producing non-2manifoldness
// in that case, a 2-valence vertex is dealt as 2 singularities in both sides
if (valence == 2 && !borderSideB)
singSideA = true;
// compute the valence of the vertex on side A
startPos.FlipV();
valence = startPos.NumberOfIncidentVertices();
// if the vertex is on border increment its valence by 1 (virtually connect it to a dummy vertex)
jmpPos.Set(startPos.F(), startPos.E(), startPos.V());
if (jmpPos.FindBorder())
valence++;
if (valence != 4)
singSideA = true;
// a 2-valence internal vertex cause a polychord to touch itself, producing non-2manifoldness
// in that case, a 2-valence vertex is dealt as 2 singularities in both sides
if (valence == 2 && !borderSideA)
singSideB = true;
}
// if the first border has been reached, go on the other direction to find the other border
if (startPos != pos && startPos.IsBorder() && !polyBorderFound) {
startPos = pos;
startPos.FlipF();
polyBorderFound = true;
}
// if the other border has been reached, return
if (polyBorderFound && startPos.IsBorder())
break;
// go to the next edge
startPos.FlipE();
startPos.FlipV();
startPos.FlipE();
// check manifoldness
if (IsVertexAdjacentToAnyNonManifoldEdge(startPos))
return PC_NOTMANIF;
startPos.FlipV();
if (IsVertexAdjacentToAnyNonManifoldEdge(startPos))
return PC_NOTMANIF;
startPos.FlipV();
// go to the next face
startPos.FlipF();
} while (startPos != pos);
// polychord with singularities on both sides can not collapse
if ((singSideA && singSideB) ||
(singSideA && borderSideB) ||
(singSideB && borderSideA))
return PC_SINGBOTH;
// polychords that are rings and have borders on both sides can not collapse
if (!polyBorderFound && borderSideA && borderSideB)
return PC_SINGBOTH;
return PC_SUCCESS;
}
/**
* @brief VisitPolychord updates the information of a polychord.
* @param mesh The mesh used for getting the face index.
* @param startPos The starting position.
* @param chords The vector of chords.
* @param mark The mark.
* @param q The visiting type.
*/
static void VisitPolychord (const PolyMeshType &mesh,
const vcg::face::Pos<FaceType> &startPos,
PC_Chords &chords,
const unsigned long mark,
const PC_ResultCode q) {
assert(!startPos.IsNull());
vcg::face::Pos<FaceType> tmpPos, runPos = startPos;
std::pair<size_t, unsigned char> face_edge(std::numeric_limits<size_t>::max(), 0);
if (runPos.F()->VN() != 4) // non-quads are not visited
return;
// follow the sequence of quads
do {
// check manifoldness
tmpPos = runPos;
do {
if (!tmpPos.IsManifold()) {
// update current coord
face_edge.first = vcg::tri::Index(mesh, tmpPos.F());
face_edge.second = tmpPos.E()%2;
chords.UpdateCoord(chords[face_edge], mark, q);
face_edge.second = (tmpPos.E()+1)%2;
chords.UpdateCoord(chords[face_edge], mark, q);
return;
}
tmpPos.FlipV();
tmpPos.FlipE();
} while (tmpPos != runPos);
// update current coord
face_edge.first = vcg::tri::Index(mesh, runPos.F());
face_edge.second = runPos.E()%2;
chords.UpdateCoord(chords[face_edge], mark, q);
// if the polychord has to collapse, i.e. q == PC_SUCCESS, also visit the orthogonal coord
if (q == PC_SUCCESS) {
face_edge.second = (runPos.E()+1)%2;
chords.UpdateCoord(chords[face_edge], mark, q);
}
runPos.FlipE();
runPos.FlipV();
runPos.FlipE();
runPos.FlipF();
} while (runPos != startPos && !runPos.IsBorder() && runPos.F()->VN() == 4);
assert(runPos == startPos || vcg::face::IsBorder(*startPos.F(),startPos.E())
|| runPos.F()->VN() != 4 || startPos.FFlip()->VN() != 4);
}
/**
* @brief IsVertexAdjacentToAnyNonManifoldEdge checks if a vertex is adjacent to any non-manifold edge.
* @param pos The starting position.
* @return true if adjacent to non-manifold edges, false otherwise.
*/
static bool IsVertexAdjacentToAnyNonManifoldEdge (const vcg::face::Pos<FaceType> &pos) {
assert(!pos.IsNull());
vcg::face::JumpingPos<FaceType> jmpPos;
jmpPos.Set(pos.F(), pos.E(), pos.V());
do {
if (!jmpPos.IsManifold())
return true;
jmpPos.NextFE();
} while (jmpPos != pos);
return false;
}
/**
* @brief IsPolychordSelfIntersecting checks if the input polychord intersects itself.
* @warning Don't call this function without being sure that it's a polychord
* (i.e. call CheckPolychordFindStartPoint() before calling IsPolychordSelfIntersecting().
* @param mesh The mesh used for getting the face index.
* @param startPos The starting position.
* @param chords The vector of chords.
* @param mark The current mark, used to identify quads already visited.
* @return true if it intersects itself, false otherwise.
*/
static bool IsPolychordSelfIntersecting (const PolyMeshType &mesh,
const vcg::face::Pos<FaceType> &startPos,
const PC_Chords &chords,
const unsigned long mark) {
assert(!startPos.IsNull());
vcg::face::Pos<FaceType> runPos = startPos;
vcg::face::Pos<FaceType> tmpPos;
std::pair<size_t, unsigned char> face_edge(std::numeric_limits<size_t>::max(), 0);
do {
assert(runPos.F()->VN() == 4);
// check if we've already crossed this face
face_edge.first = vcg::tri::Index(mesh, runPos.F());
face_edge.second = (runPos.E()+1)%2;
if (chords[face_edge].mark == mark)
return true;
// if this coord is adjacent to another coord of the same polychord
// i.e., this polychord touches itself without intersecting
// it might cause a wrong collapse, producing holes and non-2manifoldness
tmpPos = runPos;
tmpPos.FlipE();
if (!tmpPos.IsBorder()) {
tmpPos.FlipF();
face_edge.first = vcg::tri::Index(mesh, tmpPos.F());
face_edge.second = (tmpPos.E()+1)%2;
if (chords[face_edge].mark == mark)
return true;
}
tmpPos = runPos;
tmpPos.FlipV();
tmpPos.FlipE();
if (!tmpPos.IsBorder()) {
tmpPos.FlipF();
face_edge.first = vcg::tri::Index(mesh, tmpPos.F());
face_edge.second = (tmpPos.E()+1)%2;
if (chords[face_edge].mark == mark)
return true;
}
runPos.FlipE();
runPos.FlipV();
runPos.FlipE();
runPos.FlipF();
} while (runPos != startPos && !runPos.IsBorder());
return false;
}
};
}
}
#endif // POLYGON_Polychord_COLLAPSE_H