395 lines
14 KiB
C++
395 lines
14 KiB
C++
// This file is part of libigl, a simple c++ geometry processing library.
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//
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// Copyright (C) 2015 Alec Jacobson <alecjacobson@gmail.com>
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//
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// This Source Code Form is subject to the terms of the Mozilla Public License
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// v. 2.0. If a copy of the MPL was not distributed with this file, You can
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// obtain one at http://mozilla.org/MPL/2.0/.
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#include "collapse_edge.h"
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#include "circulation.h"
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#include "edge_collapse_is_valid.h"
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#include <vector>
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IGL_INLINE bool igl::collapse_edge(
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const int e,
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const Eigen::RowVectorXd & p,
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Eigen::MatrixXd & V,
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Eigen::MatrixXi & F,
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Eigen::MatrixXi & E,
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Eigen::VectorXi & EMAP,
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Eigen::MatrixXi & EF,
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Eigen::MatrixXi & EI,
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int & a_e1,
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int & a_e2,
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int & a_f1,
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int & a_f2)
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{
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// Assign this to 0 rather than, say, -1 so that deleted elements will get
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// draw as degenerate elements at vertex 0 (which should always exist and
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// never get collapsed to anything else since it is the smallest index)
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using namespace Eigen;
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using namespace std;
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const int eflip = E(e,0)>E(e,1);
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// source and destination
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const int s = eflip?E(e,1):E(e,0);
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const int d = eflip?E(e,0):E(e,1);
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if(!edge_collapse_is_valid(e,F,E,EMAP,EF,EI))
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{
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return false;
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}
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// Important to grab neighbors of d before monkeying with edges
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const std::vector<int> nV2Fd = circulation(e,!eflip,EMAP,EF,EI);
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// The following implementation strongly relies on s<d
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assert(s<d && "s should be less than d");
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// move source and destination to midpoint
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V.row(s) = p;
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V.row(d) = p;
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// Helper function to replace edge and associate information with NULL
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const auto & kill_edge = [&E,&EI,&EF](const int e)
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{
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E(e,0) = IGL_COLLAPSE_EDGE_NULL;
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E(e,1) = IGL_COLLAPSE_EDGE_NULL;
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EF(e,0) = IGL_COLLAPSE_EDGE_NULL;
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EF(e,1) = IGL_COLLAPSE_EDGE_NULL;
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EI(e,0) = IGL_COLLAPSE_EDGE_NULL;
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EI(e,1) = IGL_COLLAPSE_EDGE_NULL;
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};
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// update edge info
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// for each flap
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const int m = F.rows();
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for(int side = 0;side<2;side++)
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{
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const int f = EF(e,side);
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const int v = EI(e,side);
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const int sign = (eflip==0?1:-1)*(1-2*side);
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// next edge emanating from d
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const int e1 = EMAP(f+m*((v+sign*1+3)%3));
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// prev edge pointing to s
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const int e2 = EMAP(f+m*((v+sign*2+3)%3));
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assert(E(e1,0) == d || E(e1,1) == d);
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assert(E(e2,0) == s || E(e2,1) == s);
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// face adjacent to f on e1, also incident on d
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const bool flip1 = EF(e1,1)==f;
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const int f1 = flip1 ? EF(e1,0) : EF(e1,1);
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assert(f1!=f);
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assert(F(f1,0)==d || F(f1,1)==d || F(f1,2) == d);
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// across from which vertex of f1 does e1 appear?
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const int v1 = flip1 ? EI(e1,0) : EI(e1,1);
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// Kill e1
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kill_edge(e1);
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// Kill f
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F(f,0) = IGL_COLLAPSE_EDGE_NULL;
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F(f,1) = IGL_COLLAPSE_EDGE_NULL;
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F(f,2) = IGL_COLLAPSE_EDGE_NULL;
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// map f1's edge on e1 to e2
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assert(EMAP(f1+m*v1) == e1);
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EMAP(f1+m*v1) = e2;
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// side opposite f2, the face adjacent to f on e2, also incident on s
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const int opp2 = (EF(e2,0)==f?0:1);
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assert(EF(e2,opp2) == f);
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EF(e2,opp2) = f1;
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EI(e2,opp2) = v1;
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// remap e2 from d to s
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E(e2,0) = E(e2,0)==d ? s : E(e2,0);
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E(e2,1) = E(e2,1)==d ? s : E(e2,1);
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if(side==0)
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{
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a_e1 = e1;
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a_f1 = f;
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}else
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{
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a_e2 = e1;
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a_f2 = f;
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}
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}
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// finally, reindex faces and edges incident on d. Do this last so asserts
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// make sense.
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//
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// Could actually skip first and last, since those are always the two
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// collpased faces.
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for(auto f : nV2Fd)
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{
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for(int v = 0;v<3;v++)
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{
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if(F(f,v) == d)
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{
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const int flip1 = (EF(EMAP(f+m*((v+1)%3)),0)==f)?1:0;
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const int flip2 = (EF(EMAP(f+m*((v+2)%3)),0)==f)?0:1;
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assert(
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E(EMAP(f+m*((v+1)%3)),flip1) == d ||
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E(EMAP(f+m*((v+1)%3)),flip1) == s);
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E(EMAP(f+m*((v+1)%3)),flip1) = s;
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assert(
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E(EMAP(f+m*((v+2)%3)),flip2) == d ||
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E(EMAP(f+m*((v+2)%3)),flip2) == s);
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E(EMAP(f+m*((v+2)%3)),flip2) = s;
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F(f,v) = s;
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break;
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}
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}
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}
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// Finally, "remove" this edge and its information
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kill_edge(e);
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return true;
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}
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IGL_INLINE bool igl::collapse_edge(
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const int e,
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const Eigen::RowVectorXd & p,
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Eigen::MatrixXd & V,
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Eigen::MatrixXi & F,
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Eigen::MatrixXi & E,
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Eigen::VectorXi & EMAP,
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Eigen::MatrixXi & EF,
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Eigen::MatrixXi & EI)
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{
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int e1,e2,f1,f2;
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return collapse_edge(e,p,V,F,E,EMAP,EF,EI,e1,e2,f1,f2);
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}
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IGL_INLINE bool igl::collapse_edge(
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const std::function<void(
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const int,
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const Eigen::MatrixXd &,
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const Eigen::MatrixXi &,
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const Eigen::MatrixXi &,
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const Eigen::VectorXi &,
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const Eigen::MatrixXi &,
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const Eigen::MatrixXi &,
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double &,
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Eigen::RowVectorXd &)> & cost_and_placement,
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Eigen::MatrixXd & V,
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Eigen::MatrixXi & F,
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Eigen::MatrixXi & E,
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Eigen::VectorXi & EMAP,
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Eigen::MatrixXi & EF,
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Eigen::MatrixXi & EI,
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std::set<std::pair<double,int> > & Q,
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std::vector<std::set<std::pair<double,int> >::iterator > & Qit,
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Eigen::MatrixXd & C)
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{
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int e,e1,e2,f1,f2;
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const auto always_try = [](
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const Eigen::MatrixXd & ,/*V*/
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const Eigen::MatrixXi & ,/*F*/
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const Eigen::MatrixXi & ,/*E*/
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const Eigen::VectorXi & ,/*EMAP*/
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const Eigen::MatrixXi & ,/*EF*/
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const Eigen::MatrixXi & ,/*EI*/
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const std::set<std::pair<double,int> > & ,/*Q*/
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const std::vector<std::set<std::pair<double,int> >::iterator > &,/*Qit*/
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const Eigen::MatrixXd & ,/*C*/
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const int /*e*/
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) -> bool { return true;};
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const auto never_care = [](
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const Eigen::MatrixXd & , /*V*/
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const Eigen::MatrixXi & , /*F*/
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const Eigen::MatrixXi & , /*E*/
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const Eigen::VectorXi & ,/*EMAP*/
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const Eigen::MatrixXi & , /*EF*/
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const Eigen::MatrixXi & , /*EI*/
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const std::set<std::pair<double,int> > & , /*Q*/
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const std::vector<std::set<std::pair<double,int> >::iterator > &, /*Qit*/
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const Eigen::MatrixXd & , /*C*/
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const int , /*e*/
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const int , /*e1*/
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const int , /*e2*/
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const int , /*f1*/
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const int , /*f2*/
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const bool /*collapsed*/
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)-> void { };
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return
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collapse_edge(
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cost_and_placement,always_try,never_care,
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V,F,E,EMAP,EF,EI,Q,Qit,C,e,e1,e2,f1,f2);
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}
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IGL_INLINE bool igl::collapse_edge(
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const std::function<void(
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const int,
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const Eigen::MatrixXd &,
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const Eigen::MatrixXi &,
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const Eigen::MatrixXi &,
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const Eigen::VectorXi &,
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const Eigen::MatrixXi &,
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const Eigen::MatrixXi &,
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double &,
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Eigen::RowVectorXd &)> & cost_and_placement,
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const std::function<bool(
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const Eigen::MatrixXd & ,/*V*/
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const Eigen::MatrixXi & ,/*F*/
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const Eigen::MatrixXi & ,/*E*/
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const Eigen::VectorXi & ,/*EMAP*/
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const Eigen::MatrixXi & ,/*EF*/
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const Eigen::MatrixXi & ,/*EI*/
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const std::set<std::pair<double,int> > & ,/*Q*/
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const std::vector<std::set<std::pair<double,int> >::iterator > &,/*Qit*/
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const Eigen::MatrixXd & ,/*C*/
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const int /*e*/
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)> & pre_collapse,
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const std::function<void(
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const Eigen::MatrixXd & , /*V*/
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const Eigen::MatrixXi & , /*F*/
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const Eigen::MatrixXi & , /*E*/
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const Eigen::VectorXi & ,/*EMAP*/
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const Eigen::MatrixXi & , /*EF*/
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const Eigen::MatrixXi & , /*EI*/
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const std::set<std::pair<double,int> > & , /*Q*/
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const std::vector<std::set<std::pair<double,int> >::iterator > &, /*Qit*/
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const Eigen::MatrixXd & , /*C*/
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const int , /*e*/
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const int , /*e1*/
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const int , /*e2*/
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const int , /*f1*/
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const int , /*f2*/
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const bool /*collapsed*/
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)> & post_collapse,
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Eigen::MatrixXd & V,
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Eigen::MatrixXi & F,
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Eigen::MatrixXi & E,
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Eigen::VectorXi & EMAP,
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Eigen::MatrixXi & EF,
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Eigen::MatrixXi & EI,
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std::set<std::pair<double,int> > & Q,
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std::vector<std::set<std::pair<double,int> >::iterator > & Qit,
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Eigen::MatrixXd & C)
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{
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int e,e1,e2,f1,f2;
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return
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collapse_edge(
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cost_and_placement,pre_collapse,post_collapse,
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V,F,E,EMAP,EF,EI,Q,Qit,C,e,e1,e2,f1,f2);
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}
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IGL_INLINE bool igl::collapse_edge(
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const std::function<void(
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const int,
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const Eigen::MatrixXd &,
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const Eigen::MatrixXi &,
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const Eigen::MatrixXi &,
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const Eigen::VectorXi &,
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const Eigen::MatrixXi &,
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const Eigen::MatrixXi &,
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double &,
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Eigen::RowVectorXd &)> & cost_and_placement,
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const std::function<bool(
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const Eigen::MatrixXd & ,/*V*/
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const Eigen::MatrixXi & ,/*F*/
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const Eigen::MatrixXi & ,/*E*/
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const Eigen::VectorXi & ,/*EMAP*/
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const Eigen::MatrixXi & ,/*EF*/
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const Eigen::MatrixXi & ,/*EI*/
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const std::set<std::pair<double,int> > & ,/*Q*/
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const std::vector<std::set<std::pair<double,int> >::iterator > &,/*Qit*/
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const Eigen::MatrixXd & ,/*C*/
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const int /*e*/
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)> & pre_collapse,
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const std::function<void(
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const Eigen::MatrixXd & , /*V*/
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const Eigen::MatrixXi & , /*F*/
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const Eigen::MatrixXi & , /*E*/
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const Eigen::VectorXi & ,/*EMAP*/
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const Eigen::MatrixXi & , /*EF*/
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const Eigen::MatrixXi & , /*EI*/
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const std::set<std::pair<double,int> > & , /*Q*/
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const std::vector<std::set<std::pair<double,int> >::iterator > &, /*Qit*/
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const Eigen::MatrixXd & , /*C*/
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const int , /*e*/
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const int , /*e1*/
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const int , /*e2*/
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const int , /*f1*/
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const int , /*f2*/
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const bool /*collapsed*/
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)> & post_collapse,
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Eigen::MatrixXd & V,
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Eigen::MatrixXi & F,
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Eigen::MatrixXi & E,
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Eigen::VectorXi & EMAP,
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Eigen::MatrixXi & EF,
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Eigen::MatrixXi & EI,
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std::set<std::pair<double,int> > & Q,
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std::vector<std::set<std::pair<double,int> >::iterator > & Qit,
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Eigen::MatrixXd & C,
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int & e,
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int & e1,
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int & e2,
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int & f1,
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int & f2)
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{
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using namespace Eigen;
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if(Q.empty())
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{
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// no edges to collapse
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return false;
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}
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std::pair<double,int> p = *(Q.begin());
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if(p.first == std::numeric_limits<double>::infinity())
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{
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// min cost edge is infinite cost
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return false;
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}
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Q.erase(Q.begin());
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e = p.second;
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Qit[e] = Q.end();
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std::vector<int> N = circulation(e, true,EMAP,EF,EI);
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std::vector<int> Nd = circulation(e,false,EMAP,EF,EI);
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N.insert(N.begin(),Nd.begin(),Nd.end());
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bool collapsed = true;
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if(pre_collapse(V,F,E,EMAP,EF,EI,Q,Qit,C,e))
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{
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collapsed = collapse_edge(e,C.row(e),V,F,E,EMAP,EF,EI,e1,e2,f1,f2);
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}else
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{
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// Aborted by pre collapse callback
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collapsed = false;
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}
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post_collapse(V,F,E,EMAP,EF,EI,Q,Qit,C,e,e1,e2,f1,f2,collapsed);
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if(collapsed)
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{
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// Erase the two, other collapsed edges
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Q.erase(Qit[e1]);
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Qit[e1] = Q.end();
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Q.erase(Qit[e2]);
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Qit[e2] = Q.end();
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// update local neighbors
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// loop over original face neighbors
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for(auto n : N)
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{
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if(F(n,0) != IGL_COLLAPSE_EDGE_NULL ||
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F(n,1) != IGL_COLLAPSE_EDGE_NULL ||
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F(n,2) != IGL_COLLAPSE_EDGE_NULL)
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{
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for(int v = 0;v<3;v++)
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{
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// get edge id
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const int ei = EMAP(v*F.rows()+n);
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// erase old entry
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Q.erase(Qit[ei]);
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// compute cost and potential placement
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double cost;
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RowVectorXd place;
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cost_and_placement(ei,V,F,E,EMAP,EF,EI,cost,place);
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// Replace in queue
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Qit[ei] = Q.insert(std::pair<double,int>(cost,ei)).first;
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C.row(ei) = place;
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}
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}
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}
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}else
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{
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// reinsert with infinite weight (the provided cost function must **not**
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// have given this un-collapsable edge inf cost already)
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p.first = std::numeric_limits<double>::infinity();
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Qit[e] = Q.insert(p).first;
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}
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return collapsed;
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}
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