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https://github.com/SoftFever/OrcaSlicer.git
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2ae2672ee9
Fixing dep build script on Windows and removing some warnings. Use bundled igl by default. Not building with the dependency scripts if not explicitly stated. This way, it will stay in Fix the libigl patch to include C source files in header only mode.
211 lines
9.1 KiB
C++
211 lines
9.1 KiB
C++
// This file is part of libigl, a simple c++ geometry processing library.
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//
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// Copyright (C) 2016 Yotam Gingold <yotam@yotamgingold.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 "seam_edges.h"
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#include <unordered_map>
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#include <unordered_set>
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#include <cassert>
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// Yotam has verified that this function produces the exact same output as
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// `find_seam_fast.py` for `cow_triangled.obj`.
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template <
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typename DerivedV,
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typename DerivedTC,
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typename DerivedF,
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typename DerivedFTC,
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typename Derivedseams,
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typename Derivedboundaries,
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typename Derivedfoldovers>
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IGL_INLINE void igl::seam_edges(
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const Eigen::PlainObjectBase<DerivedV>& V,
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const Eigen::PlainObjectBase<DerivedTC>& TC,
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const Eigen::PlainObjectBase<DerivedF>& F,
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const Eigen::PlainObjectBase<DerivedFTC>& FTC,
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Eigen::PlainObjectBase<Derivedseams>& seams,
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Eigen::PlainObjectBase<Derivedboundaries>& boundaries,
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Eigen::PlainObjectBase<Derivedfoldovers>& foldovers)
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{
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// Assume triangles.
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assert( F.cols() == 3 );
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assert( F.cols() == FTC.cols() );
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assert( F.rows() == FTC.rows() );
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// Assume 2D texture coordinates (foldovers tests).
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assert( TC.cols() == 2 );
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typedef Eigen::Matrix< typename DerivedTC::Scalar, 2, 1 > Vector2S;
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// Computes the orientation of `c` relative to the line between `a` and `b`.
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// Assumes 2D vector input.
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// Based on: https://www.cs.cmu.edu/~quake/robust.html
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const auto& Orientation = [](
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const Vector2S& a,
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const Vector2S& b,
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const Vector2S& c ) -> typename DerivedTC::Scalar
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{
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const Vector2S row0 = a - c;
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const Vector2S row1 = b - c;
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return row0(0)*row1(1) - row1(0)*row0(1);
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};
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seams .setZero( 3*F.rows(), 4 );
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boundaries.setZero( 3*F.rows(), 2 );
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foldovers .setZero( 3*F.rows(), 4 );
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int num_seams = 0;
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int num_boundaries = 0;
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int num_foldovers = 0;
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// A map from a pair of vertex indices to the index (face and endpoints)
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// into face_position_indices.
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// The following should be true for every key, value pair:
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// key == face_position_indices[ value ]
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// This gives us a "reverse map" so that we can look up other face
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// attributes based on position edges.
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// The value are written in the format returned by numpy.where(),
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// which stores multi-dimensional indices such as array[a0,b0], array[a1,b1]
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// as ( (a0,a1), (b0,b1) ).
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// We need to make a hash function for our directed edges.
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// We'll use i*V.rows() + j.
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typedef std::pair< typename DerivedF::Scalar, typename DerivedF::Scalar >
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directed_edge;
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const int numV = V.rows();
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const int numF = F.rows();
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const auto& edge_hasher =
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[numV]( directed_edge const& e ) { return e.first*numV + e.second; };
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// When we pass a hash function object, we also need to specify the number of
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// buckets. The Euler characteristic says that the number of undirected edges
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// is numV + numF -2*genus.
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std::unordered_map<directed_edge,std::pair<int,int>,decltype(edge_hasher) >
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directed_position_edge2face_position_index(2*( numV + numF ), edge_hasher);
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for( int fi = 0; fi < F.rows(); ++fi )
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{
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for( int i = 0; i < 3; ++i )
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{
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const int j = ( i+1 ) % 3;
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directed_position_edge2face_position_index[
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std::make_pair( F(fi,i), F(fi,j) ) ] = std::make_pair( fi, i );
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}
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}
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// First find all undirected position edges (collect a canonical orientation
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// of the directed edges).
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std::unordered_set< directed_edge, decltype( edge_hasher ) >
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undirected_position_edges( numV + numF, edge_hasher );
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for( const auto& el : directed_position_edge2face_position_index )
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{
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// The canonical orientation is the one where the smaller of
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// the two vertex indices is first.
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undirected_position_edges.insert( std::make_pair(
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std::min( el.first.first, el.first.second ),
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std::max( el.first.first, el.first.second ) ) );
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}
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// Now we will iterate over all position edges.
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// Seam edges are the edges whose two opposite directed edges have different
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// texcoord indices (or one doesn't exist at all in the case of a mesh
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// boundary).
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for( const auto& vp_edge : undirected_position_edges )
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{
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// We should only see canonical edges,
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// where the first vertex index is smaller.
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assert( vp_edge.first < vp_edge.second );
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const auto vp_edge_reverse = std::make_pair(vp_edge.second, vp_edge.first);
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// If it and its opposite exist as directed edges, check if their
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// texture coordinate indices match.
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if( directed_position_edge2face_position_index.count( vp_edge ) &&
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directed_position_edge2face_position_index.count( vp_edge_reverse ) )
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{
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const auto forwards =
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directed_position_edge2face_position_index[ vp_edge ];
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const auto backwards =
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directed_position_edge2face_position_index[ vp_edge_reverse ];
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// NOTE: They should never be equal.
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assert( forwards != backwards );
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// If the texcoord indices match (are similarly flipped),
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// this edge is not a seam. It could be a foldover.
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if(
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std::make_pair(
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FTC( forwards.first, forwards.second ),
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FTC( forwards.first, ( forwards.second+1 ) % 3 ) )
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==
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std::make_pair(
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FTC( backwards.first, ( backwards.second+1 ) % 3 ),
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FTC( backwards.first, backwards.second ) ))
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{
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// Check for foldovers in UV space.
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// Get the edge (a,b) and the two opposite vertices's texture
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// coordinates.
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const Vector2S a = TC.row( FTC( forwards.first, forwards.second ) );
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const Vector2S b =
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TC.row( FTC( forwards.first, (forwards.second+1) % 3 ) );
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const Vector2S c_forwards =
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TC.row( FTC( forwards .first, (forwards .second+2) % 3 ) );
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const Vector2S c_backwards =
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TC.row( FTC( backwards.first, (backwards.second+2) % 3 ) );
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// If the opposite vertices' texture coordinates fall on the same side
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// of the edge, we have a UV-space foldover.
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const auto orientation_forwards = Orientation( a, b, c_forwards );
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const auto orientation_backwards = Orientation( a, b, c_backwards );
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if( ( orientation_forwards > 0 && orientation_backwards > 0 ) ||
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( orientation_forwards < 0 && orientation_backwards < 0 )
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) {
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foldovers( num_foldovers, 0 ) = forwards.first;
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foldovers( num_foldovers, 1 ) = forwards.second;
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foldovers( num_foldovers, 2 ) = backwards.first;
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foldovers( num_foldovers, 3 ) = backwards.second;
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num_foldovers += 1;
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}
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}
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// Otherwise, we have a non-matching seam edge.
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else
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{
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seams( num_seams, 0 ) = forwards.first;
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seams( num_seams, 1 ) = forwards.second;
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seams( num_seams, 2 ) = backwards.first;
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seams( num_seams, 3 ) = backwards.second;
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num_seams += 1;
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}
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}
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// Otherwise, the edge and its opposite aren't both in the directed edges.
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// One of them should be.
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else if( directed_position_edge2face_position_index.count( vp_edge ) )
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{
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const auto forwards = directed_position_edge2face_position_index[vp_edge];
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boundaries( num_boundaries, 0 ) = forwards.first;
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boundaries( num_boundaries, 1 ) = forwards.second;
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num_boundaries += 1;
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} else if(
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directed_position_edge2face_position_index.count( vp_edge_reverse ) )
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{
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const auto backwards =
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directed_position_edge2face_position_index[ vp_edge_reverse ];
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boundaries( num_boundaries, 0 ) = backwards.first;
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boundaries( num_boundaries, 1 ) = backwards.second;
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num_boundaries += 1;
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} else {
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// This should never happen! One of these two must have been seen.
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assert(
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directed_position_edge2face_position_index.count( vp_edge ) ||
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directed_position_edge2face_position_index.count( vp_edge_reverse )
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);
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}
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}
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seams .conservativeResize( num_seams, Eigen::NoChange_t() );
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boundaries.conservativeResize( num_boundaries, Eigen::NoChange_t() );
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foldovers .conservativeResize( num_foldovers, Eigen::NoChange_t() );
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}
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#ifdef IGL_STATIC_LIBRARY
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// Explicit template instantiation
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// generated by autoexplicit.sh
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template void igl::seam_edges<Eigen::Matrix<double, -1, -1, 0, -1, -1>, Eigen::Matrix<double, -1, -1, 0, -1, -1>, Eigen::Matrix<int, -1, -1, 0, -1, -1>, Eigen::Matrix<int, -1, -1, 0, -1, -1>, Eigen::Matrix<int, -1, -1, 0, -1, -1>, Eigen::Matrix<int, -1, -1, 0, -1, -1>, Eigen::Matrix<int, -1, -1, 0, -1, -1> >(Eigen::PlainObjectBase<Eigen::Matrix<double, -1, -1, 0, -1, -1> > const&, Eigen::PlainObjectBase<Eigen::Matrix<double, -1, -1, 0, -1, -1> > const&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, -1, 0, -1, -1> > const&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, -1, 0, -1, -1> > const&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, -1, 0, -1, -1> >&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, -1, 0, -1, -1> >&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, -1, 0, -1, -1> >&);
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#endif
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