second version

Author: panquez

src/geode/mesh/helpers/convert_surface_mesh.cpp

@@ -346,19 +346,53 @@ namespace geode
         SurfaceMeshBuilder< dimension >& builder )
     {
         std::vector< bool > to_delete( surface.nb_polygons(), false );
-        for( const auto p : geode::Range{ surface.nb_polygons() } )
+        for( const auto p : Range{ surface.nb_polygons() } )
         {
             const auto nb_vertices = surface.nb_polygon_vertices( p );
             to_delete[p] = nb_vertices != 3;
             if( nb_vertices > 3 )
             {
+                DEBUG( "====== " );
+                DEBUG( p );
+                absl::FixedArray< std::optional< PolygonEdge > > adjacents(
+                    nb_vertices, std::nullopt );
+                for( const auto e : LRange{ nb_vertices } )
+                {
+                    adjacents[e] = surface.polygon_adjacent_edge( { p, e } );
+                }
                 std::vector< index_t > new_polygons;
                 new_polygons.reserve( nb_vertices - 2 );
                 const auto vertices = surface.polygon_vertices( p );
                 for( const auto v : LRange{ 2, nb_vertices } )
                 {
                     new_polygons.emplace_back( builder.create_polygon(
                         { vertices[0], vertices[v - 1], vertices[v] } ) );
+                    DEBUG( new_polygons.back() );
+                }
+                if( adjacents.front() )
+                {
+                    builder.set_polygon_adjacent( { new_polygons.front(), 0 },
+                        adjacents.front()->polygon_id );
+                    builder.set_polygon_adjacent(
+                        adjacents.front().value(), new_polygons.front() );
+                }
+                for( const auto v : LRange{ 1, nb_vertices - 1 } )
+                {
+                    if( adjacents[v] )
+                    {
+                        builder.set_polygon_adjacent(
+                            { new_polygons[v - 1], 1 },
+                            adjacents[v]->polygon_id );
+                        builder.set_polygon_adjacent(
+                            adjacents[v].value(), new_polygons[v - 1] );
+                    }
+                }
+                if( adjacents.back() )
+                {
+                    builder.set_polygon_adjacent( { new_polygons.back(), 2 },
+                        adjacents.back()->polygon_id );
+                    builder.set_polygon_adjacent(
+                        adjacents.back().value(), new_polygons.back() );
                 }
                 builder.compute_polygon_adjacencies( new_polygons );
             }