fix(Mesh): add helpers to remove elements having same vertices

include/geode/mesh/helpers/remove_element_duplication.hpp

@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2019 - 2025 Geode-solutions
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+
+#pragma once
+
+#include <geode/mesh/common.hpp>
+
+namespace geode
+{
+    FORWARD_DECLARATION_DIMENSION_CLASS( PointSet );
+    FORWARD_DECLARATION_DIMENSION_CLASS( EdgedCurve );
+    FORWARD_DECLARATION_DIMENSION_CLASS( SurfaceMesh );
+    FORWARD_DECLARATION_DIMENSION_CLASS( SolidMesh );
+    FORWARD_DECLARATION_DIMENSION_CLASS( PointSetBuilder );
+    FORWARD_DECLARATION_DIMENSION_CLASS( EdgedCurveBuilder );
+    FORWARD_DECLARATION_DIMENSION_CLASS( SurfaceMeshBuilder );
+    FORWARD_DECLARATION_DIMENSION_CLASS( SolidMeshBuilder );
+    ALIAS_3D( SolidMesh );
+    ALIAS_3D( SolidMeshBuilder );
+} // namespace geode
+
+namespace geode
+{
+    template < index_t dimension >
+    void remove_edge_duplication( const EdgedCurve< dimension >& mesh,
+        EdgedCurveBuilder< dimension >& builder );
+
+    template < index_t dimension >
+    void remove_polygon_duplication( const SurfaceMesh< dimension >& mesh,
+        SurfaceMeshBuilder< dimension >& builder );
+
+    void opengeode_mesh_api remove_polyhedron_duplication(
+        const SolidMesh3D& mesh, SolidMeshBuilder3D& builder );
+} // namespace geode

src/geode/mesh/CMakeLists.txt

@@ -116,6 +116,7 @@ add_geode_library(
         "helpers/grid_scalar_function.cpp"
         "helpers/repair_polygon_orientations.cpp"
         "helpers/remove_vertex_duplication.cpp"
+        "helpers/remove_element_duplication.cpp"
         "helpers/tetrahedral_solid_point_function.cpp"
         "helpers/tetrahedral_solid_scalar_function.cpp"
         "helpers/triangulated_surface_point_function.cpp"
@@ -259,6 +260,7 @@ add_geode_library(
         "helpers/grid_scalar_function.hpp"
         "helpers/repair_polygon_orientations.hpp"
         "helpers/remove_vertex_duplication.hpp"
+        "helpers/remove_element_duplication.hpp"
         "helpers/tetrahedral_solid_point_function.hpp"
         "helpers/tetrahedral_solid_scalar_function.hpp"
         "helpers/triangulated_surface_point_function.hpp"

src/geode/mesh/helpers/remove_element_duplication.cpp

@@ -0,0 +1,155 @@
+/*
+ * Copyright (c) 2019 - 2025 Geode-solutions
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+
+#include <geode/mesh/helpers/remove_element_duplication.hpp>
+
+#include <geode/mesh/builder/edged_curve_builder.hpp>
+#include <geode/mesh/builder/solid_edges_builder.hpp>
+#include <geode/mesh/builder/solid_facets_builder.hpp>
+#include <geode/mesh/builder/solid_mesh_builder.hpp>
+#include <geode/mesh/builder/surface_edges_builder.hpp>
+#include <geode/mesh/builder/surface_mesh_builder.hpp>
+#include <geode/mesh/core/edged_curve.hpp>
+#include <geode/mesh/core/solid_mesh.hpp>
+#include <geode/mesh/core/surface_mesh.hpp>
+#include <geode/mesh/helpers/generic_edged_curve_accessor.hpp>
+#include <geode/mesh/helpers/generic_solid_accessor.hpp>
+#include <geode/mesh/helpers/generic_surface_accessor.hpp>
+
+namespace
+{
+
+    template < typename Mesh >
+    absl::flat_hash_map< geode::index_t, std::vector< geode::index_t > >
+        compute_vertex_to_element_mapping( const Mesh& mesh )
+    {
+        using Accessor = geode::GenericMeshAccessor< Mesh >;
+        const Accessor accessor{ mesh };
+        absl::flat_hash_map< geode::index_t, std::vector< geode::index_t > >
+            vertex_to_element;
+        for( const auto element_id : geode::Range{ accessor.nb_elements() } )
+        {
+            for( const auto vertex_id :
+                accessor.element_vertices( element_id ) )
+            {
+                vertex_to_element[vertex_id].push_back( element_id );
+            }
+        }
+        return vertex_to_element;
+    }
+
+    template < geode::index_t dimension >
+    void delete_elements( const std::vector< bool >& to_delete,
+        geode::EdgedCurveBuilder< dimension >& builder )
+    {
+        builder.delete_edges( to_delete );
+    }
+    template < geode::index_t dimension >
+    void delete_elements( const std::vector< bool >& to_delete,
+        geode::SurfaceMeshBuilder< dimension >& builder )
+    {
+        builder.delete_polygons( to_delete );
+    }
+    template < geode::index_t dimension >
+    void delete_elements( const std::vector< bool >& to_delete,
+        geode::SolidMeshBuilder< dimension >& builder )
+    {
+        builder.delete_polyhedra( to_delete );
+    }
+
+    template < typename Mesh, typename Builder >
+    void remove_element_duplication( const Mesh& mesh, Builder& builder )
+    {
+        const auto vertex_to_element =
+            compute_vertex_to_element_mapping( mesh );
+        using Accessor = geode::GenericMeshAccessor< Mesh >;
+        const Accessor accessor{ mesh };
+        std::vector< bool > to_delete( accessor.nb_elements(), false );
+        for( const auto element_id : geode::Range{ accessor.nb_elements() } )
+        {
+            if( to_delete[element_id] )
+            {
+                continue;
+            }
+            const auto element_vertices =
+                accessor.element_vertices( element_id );
+            std::vector< geode::index_t > common_elements =
+                vertex_to_element.at( element_vertices[0] );
+            for( const auto v :
+                geode::LRange{ 1, accessor.nb_element_vertices( element_id ) } )
+            {
+                std::vector< geode::index_t > temp;
+                absl::c_set_intersection( common_elements,
+                    vertex_to_element.at( element_vertices[v] ),
+                    std::back_inserter( temp ) );
+                common_elements = std::move( temp );
+            }
+            if( common_elements.size() > 1 )
+            {
+                for( const auto common_element_id : common_elements )
+                {
+                    if( element_id == common_element_id )
+                    {
+                        continue;
+                    }
+                    to_delete[common_element_id] = true;
+                }
+            }
+        }
+        delete_elements( to_delete, builder );
+    }
+} // namespace
+
+namespace geode
+{
+    template < index_t dimension >
+    void remove_edge_duplication( const EdgedCurve< dimension >& mesh,
+        EdgedCurveBuilder< dimension >& builder )
+    {
+        ::remove_element_duplication( mesh, builder );
+    }
+
+    template < index_t dimension >
+    void remove_polygon_duplication( const SurfaceMesh< dimension >& mesh,
+        SurfaceMeshBuilder< dimension >& builder )
+    {
+        ::remove_element_duplication( mesh, builder );
+    }
+
+    void remove_polyhedron_duplication(
+        const SolidMesh3D& mesh, SolidMeshBuilder3D& builder )
+    {
+        ::remove_element_duplication( mesh, builder );
+    }
+
+    template void opengeode_mesh_api remove_edge_duplication(
+        const EdgedCurve2D&, EdgedCurveBuilder2D& );
+    template void opengeode_mesh_api remove_edge_duplication(
+        const EdgedCurve3D&, EdgedCurveBuilder3D& );
+
+    template void opengeode_mesh_api remove_polygon_duplication(
+        const SurfaceMesh2D&, SurfaceMeshBuilder2D& );
+    template void opengeode_mesh_api remove_polygon_duplication(
+        const SurfaceMesh3D&, SurfaceMeshBuilder3D& );
+
+} // namespace geode

src/geode/mesh/helpers/repair_polygon_orientations.cpp

@@ -97,6 +97,16 @@ namespace
                                       == reorient_polygon_[adj->polygon_id]
                                 : cur_polygon_reorient
                                       != reorient_polygon_[adj->polygon_id];
+                        if( !is_valid )
+                        {
+                            DEBUG( "Mobius strip detected" );
+                            DEBUG( cur_polygon );
+                            DEBUG( e );
+                            SDEBUG( adj.value() );
+                            SDEBUG( mesh_.polygon_barycenter( cur_polygon ) );
+                            SDEBUG(
+                                mesh_.polygon_barycenter( adj->polygon_id ) );
+                        }
                         OPENGEODE_DATA_EXCEPTION( is_valid,
                             "[RepairPolygonOrientations] Mobius "
                             "strip detected, polygons orientations "