[英]Iterating over edges and getting their vertices with OpenMesh
I am starting to use OpenMesh to go through meshes which may have wholes and am wondering what is the good way to actually retrieve the vertices associated with each edge. 我开始使用OpenMesh遍历可能具有整体的网格,并且想知道什么是实际检索与每个边缘关联的顶点的好方法。
For half-edges, there are the methods opposite_he_opposite_vh
and opposite_vh
of the mesh, but these trigger an error if the opposite half-edge does not exist (we are currently on a boundary half-edge). 对于半边,有网格的
opposite_he_opposite_vh
和opposite_vh
_vh方法,但是如果不存在相反的半边(我们当前在边界半边上),它们会触发错误。
Given that I'll encounter these often, what's a better way to iterate over all edges (I actually don't specifically care about half-edge, I'm getting data for each edge, but the direction doesn't matter. What I need are the two vertices)? 考虑到我会经常遇到这些问题,有什么更好的方法可以遍历所有边缘(实际上我并不特别在意半边,我正在获取每个边的数据,但是方向并不重要。需要两个顶点)吗?
I think you can use: 我认为您可以使用:
MyMesh::to_vertex_handle(MyMesh::HalfedgeHandle)
MyMesh::from_vertex_handle(MyMesh::HalfedgeHandle)
Please confirm you can find these methods :-) 请确认您可以找到以下方法:-)
What you want might be this example: 您想要的可能是以下示例:
for ( mesh_t::EdgeIter eit = _m.edges_begin(); eit != edgesEnd; ++eit) {
const MeshType::Point to = _m.point(_m.to_vertex_handle(_m.halfedge_handle(eit,0)));
const MeshType::Point from = _m.point(_m.from_vertex_handle(_m.halfedge_handle(eit,0)));
}
One of the other answers didn't work for me b/c iterators needed to be dereferenced. 其他答案之一对我不起作用b / c迭代器需要取消引用。 This is how I do it using OpenMesh 4.1
这就是我使用OpenMesh 4.1的方法
Best practices may have changed somewhat; 最佳做法可能有所改变; OpenMesh 6.2 is now out, but I haven't switched yet.
OpenMesh 6.2现在已经发布,但是我还没有切换。
MyMesh mesh; // create the mesh instance
... // build your mesh
// use an edge iterator to iterate over all the edges
for (MyMesh::EdgeIter eit = mesh.edges_begin(); eit != mesh.edges_end(); ++eit)
{
// check for boundary. (one halfedge won't be valid if boundary)
// note: you have to dereference the edge iterator
if (!mesh.is_boundary(*eit))
{
// if you want vertex handles use:
auto vh1 = mesh.to_vertex_handle(mesh.halfedge_handle(*eit, 0));
auto vh2 = mesh.from_vertex_handle(mesh.halfedge_handle(*eit, 0));
// if you want handles of faces adjacent to the edge use:
auto fh1 = mesh.face_handle(mesh.halfedge_handle(*eit, 0));
auto fh2 = mesh.opposite_face_handle(mesh.halfedge_handle(*eit, 0));
// if you need normal vectors of those faces use:
auto face1Norm = mesh.normal(fh1);
auto face2Norm = mesh.normal(fh2);
}
else // boundary. One of the half edges won't be valid
std::cout << "found a boundary edge. skipping it" << std::endl;
}
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