py_api.cpp

#include <vector>
#include <array>
#include <tuple>
#include <pybind11/pybind11.h>
#include <pybind11/stl.h>
#include "marchingcubes.h"

#include <pybind11/eigen.h>
#include <Eigen/Dense>

namespace py = pybind11;
using namespace std;
using namespace Eigen;

tuple<MatrixXd, MatrixXi, vector<uint>, vector<uint>, vector<bool>>
marching_cubes(const py::EigenDRef<VectorXd> arr_flatten, const array<int, 3>& shape, double isovalue)
{
    // here we use EigenDRef as it does not make a copy caues it's just a refernce 
    // pybind11 seems not support pass by reference for std::vector
    array<int, 3> lower{0, 0, 0};
    array<int, 3> upper{shape[0]-1, shape[1]-1, shape[2]-1};
    int numx = upper[0] - lower[0] + 1;
    int numy = upper[1] - lower[1] + 1;
    int numz = upper[2] - lower[2] + 1;

    auto access_3d_arr = [&](int i, int j, int k){
        auto idx = i * shape[1] * shape[2] + j * shape[2] + k;
        return arr_flatten(idx);
    };

    auto tm = TableManager(numx, numy, numz);
    tm.reset();
    return mc::marching_cubes(lower, upper, numx, numy, numz, access_3d_arr, isovalue, tm);
}

class MarchingCubeStaticSize
{
    public:
        TableManager tm;
        array<int, 3> shape;
        MarchingCubeStaticSize(const array<int, 3>& shape_) 
            : tm(TableManager(shape_[0], shape_[1], shape_[2])), shape(shape_) {}

        tuple<MatrixXd, MatrixXi, vector<uint>, vector<uint>, vector<bool>>
        compute(const py::EigenDRef<VectorXd> arr_flatten, double isovalue){
            array<int, 3> lower{0, 0, 0};
            array<int, 3> upper{shape[0]-1, shape[1]-1, shape[2]-1};
            int numx = upper[0] - lower[0] + 1;
            int numy = upper[1] - lower[1] + 1;
            int numz = upper[2] - lower[2] + 1;

            auto access_3d_arr = [&](int i, int j, int k){
                auto idx = i * shape[1] * shape[2] + j * shape[2] + k;
                return arr_flatten(idx);
            };

            tm.reset();
            return mc::marching_cubes(lower, upper, numx, numy, numz, access_3d_arr, isovalue, tm);
        }


};


PYBIND11_MODULE(mcube, m) {
    m.doc() = "python wrapper"; 
    m.def("marching_cube", &marching_cubes, "marching cube method");
    py::class_<MarchingCubeStaticSize>(m, "MarchingCubeStaticSize")
            .def(py::init<std::array<int, 3>&>())
            .def("compute", &MarchingCubeStaticSize::compute);
}