SplineParametrizations.hpp

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#pragma once
 
#include "Parametrization.hpp"
 
#include <Eigen/Core>
 
namespace polyfem
{
    class State;
    class BSplineParametrization2D;
    class BSplineParametrization3D;
} // namespace polyfem
 
namespace polyfem::solver
{
    class BSplineParametrization1DTo2D : public Parametrization
    {
    public:
        BSplineParametrization1DTo2D(const Eigen::MatrixXd &initial_control_points, const Eigen::VectorXd &knots, const int num_vertices, const bool exclude_ends = true)
            : initial_control_points_(initial_control_points), knots_(knots), size_(num_vertices), exclude_ends_(exclude_ends) {}
 
        // Should only be called to initialize the parameter, when the shape matches the initial control points.
        Eigen::VectorXd inverse_eval(const Eigen::VectorXd &y) override;
        inline int size(const int x_size) const override
        {
            return 2 * size_;
        };
        Eigen::VectorXd eval(const Eigen::VectorXd &x) const override;
        Eigen::VectorXd apply_jacobian(const Eigen::VectorXd &grad_full, const Eigen::VectorXd &x) const override;
 
    private:
        const Eigen::MatrixXd initial_control_points_;
        const Eigen::VectorXd knots_;
 
        bool invoked_inverse_eval_ = false;
 
        const int size_;
 
        std::shared_ptr<BSplineParametrization2D> spline_;
 
        const bool exclude_ends_;
    };
 
    class BSplineParametrization2DTo3D : public Parametrization
    {
    public:
        BSplineParametrization2DTo3D(const Eigen::MatrixXd &initial_control_point_grid, const Eigen::VectorXd &knots_u, const Eigen::VectorXd &knots_v, const bool exclude_ends = true) : initial_control_point_grid_(initial_control_point_grid), knots_u_(knots_u), knots_v_(knots_v), exclude_ends_(exclude_ends) {}
 
        // Should only be called to initialize the parameter, when the shape matches the initial control points.
        Eigen::VectorXd inverse_eval(const Eigen::VectorXd &y) override;
        int size(const int x_size) const override { return 3 * u_.size() * v_.size(); }
        Eigen::VectorXd eval(const Eigen::VectorXd &x) const override;
        Eigen::VectorXd apply_jacobian(const Eigen::VectorXd &grad_full, const Eigen::VectorXd &x) const override;
 
    private:
        const Eigen::MatrixXd initial_control_point_grid_;
        const Eigen::VectorXd knots_u_;
        const Eigen::VectorXd knots_v_;
 
        std::shared_ptr<BSplineParametrization3D> spline_;
 
        Eigen::VectorXd u_;
        Eigen::VectorXd v_;
 
        bool invoked_inverse_eval_ = false;
 
        const bool exclude_ends_;
    };
 
    class BoundedBiharmonicWeights2Dto3D : public Parametrization
    {
    public:
        BoundedBiharmonicWeights2Dto3D(const int num_control_vertices, const int num_vertices, const Eigen::MatrixXd &V_surface, const Eigen::MatrixXi &F_surface) : num_control_vertices_(num_control_vertices), num_vertices_(num_vertices), V_surface_(V_surface), F_surface_(F_surface), allow_rotations_(true) {}
        BoundedBiharmonicWeights2Dto3D(const int num_control_vertices, const int num_vertices, const State &state, const bool allow_rotations);
 
        // Should only be called to initialize the parameter, when the shape matches the initial control points.
        Eigen::VectorXd inverse_eval(const Eigen::VectorXd &y) override;
        int size(const int x_size) const override { return num_vertices_ * 3; }
        Eigen::VectorXd eval(const Eigen::VectorXd &x) const override;
        Eigen::VectorXd apply_jacobian(const Eigen::VectorXd &grad_full, const Eigen::VectorXd &x) const override;
 
        Eigen::MatrixXd get_bbw_weights() { return bbw_weights_; }
 
    private:
        void compute_faces_for_partial_vertices(const Eigen::MatrixXd &V, Eigen::MatrixXi &F) const;
 
        int optimal_new_control_point_idx(const Eigen::MatrixXd &V, const Eigen::MatrixXi &F, const Eigen::VectorXi &boundary_loop, const std::vector<int> &existing_points) const;
 
        const int num_control_vertices_;
        const int num_vertices_;
        Eigen::MatrixXd control_points_;
        Eigen::MatrixXd bbw_weights_;
        Eigen::MatrixXd boundary_bbw_weights_;
 
        Eigen::MatrixXd V_surface_;
        Eigen::MatrixXi F_surface_;
 
        Eigen::VectorXd y_start;
 
        bool invoked_inverse_eval_ = false;
 
        const bool allow_rotations_;
    };
 
} // namespace polyfem::solver