Commit e257be3e authored by Max Lyon's avatar Max Lyon

add docu

parent 123fe55b
Pipeline #15356 passed with stages
in 91 minutes and 10 seconds
#include <OpenMesh/Core/IO/MeshIO.hh>
#include <OpenMesh/Core/Mesh/DefaultTriMesh.hh>
#include <OpenMesh/Core/Utils/PropertyManager.hh>
#include <OpenMesh/Core/Utils/Predicates.hh>
#include <iostream>
#include <vector>
using MyMesh = OpenMesh::TriMesh;
bool is_divisible_by_3(OpenMesh::FaceHandle vh) { return vh.idx() % 3 == 0; }
int main(int argc, char** argv)
{
using namespace OpenMesh::Predicates; // for easier access to predicates
// Read command line options
MyMesh mesh;
if (argc != 4) {
std::cerr << "Usage: " << argv[0] << " infile" << std::endl;
return 1;
}
const std::string infile = argv[1];
// Read mesh file
if (!OpenMesh::IO::read_mesh(mesh, infile)) {
std::cerr << "Error: Cannot read mesh from " << infile << std::endl;
return 1;
}
// Count boundary vertices
std::cout << "Mesh contains " << mesh.vertices().count_if(Boundary()) << " boundary vertices";
// Selected inner vertices
std::cout << "These are the selected inner vertices: " << std::endl;
for (auto vh : mesh.vertices().filtered(!Boundary() && Selected()))
std::cout << vh.idx() << ", ";
std::cout << std::endl;
// Faces whose id is divisible by 3
auto vec = mesh.faces().filtered(is_divisible_by_3).to_vector();
std::cout << "There are " << vec.size() << " faces whose id is divisible by 3" << std::endl;
// Faces which are tagged or whose id is not divisible by 3
auto vec2 = mesh.faces().filtered(Tagged() || !make_predicate(is_divisible_by_3)).to_vector();
std::cout << "There are " << vec2.size() << " faces which are tagged or whose id is not divisible by 3" << std::endl;
// Edges that are longer than 10 or shorter than 2
OpenMesh::EProp<bool> longer_than_10(mesh);
for (auto eh : mesh.edges())
longer_than_10[eh] = mesh.calc_edge_length(eh) > 10;
std::cout << "There are " <<
mesh.edges().count_if(make_predicate(longer_than_10) || make_predicate([&](OpenMesh::EdgeHandle eh) { return mesh.calc_edge_length(eh) < 2; })) <<
" edges which are shorter than 2 or longer than 10" << std::endl;
}
......@@ -83,6 +83,7 @@ repeatedly replacing each vertex' position by the center of gravity
\li \ref tutorial_03
\li \ref tutorial_04
\li \ref tutorial_11
\li \ref tutorial_12
\li \ref tutorial_05
\li \ref tutorial_06
\li \ref tutorial_07
......
......@@ -71,7 +71,7 @@ Similarily we compute the update vector as the laplace of the freshly computed l
Finally, we apply the update after damping it by a factor of -0.5.
\skipline udpate points
\skipline update points
\until bi_laplace
Below is the complete source code:
......
/** \page tutorial_12 Filtering ranges with predicates
This examples shows:
- How to use predicates to filter which elements of a mesh you want iterate over
In the previous tutorial we discussed already that the ranges returned by functions like all_vertices(), voh_range() or outgoing_halfedges() provide a few helpful methods such as avg() or to_vector(). Another interesting method is filtered() which requires as argument something that can be called for an element of the range and returns a bool. The resulting range will then only iterate over elements for which the filter returs true.
The filter can be a lambda, a function pointer, a property manager holding a bool property, or a functor object such as the predicates defined in <OpenMesh/Core/Utils/Predicates.hh>. The predefined predicates can check the status of a mesh element and test if they are boundary.
With their help you can for example count all boundary vertices:
\dontinclude 12-predicates/predicates.cc
\skipline Count boundary vertices
\until boundary vertices
Predicates can be composed using the operators ||, &&, and !. This enables you to specify precisely which elements you want process in your loop, e.g. inner vertices that are selected:
\skipline Selected inner vertices
\until std::cout << std::endl
As mentioned above, the filter argument can be anything returning a bool for a given input, e.g. a function pointer:
\skipline Faces whose id is divisible by 3
\until faces whose id is divisible by 3
However, function pointers, lambdas etc are not composable. Fortunately, you can use make_predicate to turn them into composable predicates:
\skipline Faces which are tagged or whose id is not divisible by 3
\until faces which are tagged or whose id is not divisible by 3
Below is the complete source code:
\include 12-predicates/predicates.cc
---
*/
......@@ -34,6 +34,7 @@ repeatedly replacing each vertex' position by the center of gravity
<li> \subpage tutorial_03
<li> \subpage tutorial_04
<li> \subpage tutorial_11
<li> \subpage tutorial_12
<li> \subpage tutorial_05
<li> \subpage tutorial_06
<li> \subpage tutorial_07
......
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