ImplicitSurfaceNetwork/primitive_process/interface/subface/simple/cylinder_face.hpp

#pragma once

#include <base/subface.hpp>

namespace internal
{
// local: cylinder face x^2+y^2-1=0
// u: planar angle from x-axis to z-axis
// v: depth/height from xz-plane to y-axis
struct cylinder_face_t final : subface {
};
} // namespace internal

namespace detail
{
template <>
struct hasher<internal::cylinder_face_t> {
    // Q' = M^{-T}QM^{-1}
    // Q = {
    // 1, 0, 0, 0
    // 0, 1, 0, 0
    // 0, 0, 0, 0
    // 0, 0, 0, -1
    // }
    size_t operator()(const internal::cylinder_face_t& subface) const
    {
        // build M^{-T}Q directly
        Eigen::Matrix4d mat = internal::empty_affine_matrix;
        mat.leftCols<2>()   = subface.world_to_local.matrix().topRows<2>().transpose();
        auto res            = mat * subface.world_to_local;
        return hash_funcs(res.matrix());
    }

    // size_t operator()(const internal::cylinder_face_t& subface) const
    // {
    //     auto R = subface.world_to_local.linear().topLeftCorner<2, 3>(); // 2x3
    //     auto b = subface.local_to_world.translation();                  // 3x1

    //     Eigen::Matrix<double, 3, 4> hash_mat = Eigen::Matrix<double, 3, 4>::Zero();
    //     hash_mat.topLeftCorner<3, 3>()       = R.transpose() * R;
    //     hash_mat.topRightCorner<2, 1>()      = R * b;

    //     return hash_funcs(hash_mat);
    // }
};
} // namespace detail