如何从网格中删除面列表及其顶点

Question

我正在尝试从网格中删除面列表及其各自的顶点（如果它们不再被引用），但到目前为止我只能成功删除面列表。这个想法是，对于删除的每个索引，所有大于删除的索引的索引都应减 1。

网格仅由顶点列表和索引列表（以及可选的三角形列表）表示。

目前删除三角形的代码是这样做的：

    private IMesh DeleteTriangles(IMesh input, IEnumerable<int> indices_to_delete)
    {
        var triangles_to_delete = new HashSet<int>(indices_to_delete);

        _triangles_to_keep = _mesh.Triangles.Where((t, count) =>
            !triangles_to_delete.Contains(t.A) &&
            !triangles_to_delete.Contains(t.B) &&
            !triangles_to_delete.Contains(t.C)).ToList();

       // return new mesh
    }

Answer 1

最后我想到的解决方案：

    public IMesh DeleteVertices(IMesh mesh, IImmutableList<int> indices_to_remove)
    {
        var indices_to_remove_set = new HashSet<int>(indices_to_remove);
        var new_vertices = new List<Vector>();
        var map = new int[mesh.Vertices.Count];

        for (var i = 0; i < mesh.Vertices.Count; i++)
        {
            if (indices_to_remove_set.Contains(i))
            {
                map[i] = -1;
            }
            else
            {
                new_vertices.Add(mesh.Vertices[i]);
                map[i] = new_vertices.Count - 1;
            }
        }

        var new_triangle_list = from triangle in mesh.Triangles
                                where map[triangle.A] != -1 &&
                                      map[triangle.B] != -1 &&
                                      map[triangle.C] != -1
                                select new IndexTriangle(
                                    map[triangle.A],
                                    map[triangle.B],
                                    map[triangle.C]);

        //build new mesh...
    }

如何从网格中删除面列表及其顶点

How to remove list of faces and it's vertices from a mesh

c#

c++

algorithm

geometry

mesh