GeodesicEngine.h

/*
 * Copyright 2025 Adobe. All rights reserved.
 * This file is licensed to you under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License. You may obtain a copy
 * of the License at http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under
 * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
 * OF ANY KIND, either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
#pragma once
 
#include <lagrange/SurfaceMesh.h>
#include <lagrange/geodesic/api.h>
 
#include <array>
#include <functional>
#include <vector>
 
namespace lagrange::geodesic {

struct LA_GEODESIC_API SingleSourceGeodesicOptions
{
    size_t source_facet_id = 0;

    std::array<double, 2> source_facet_bc = {0.0f, 0.0f};

    std::array<double, 3> ref_dir = {0.0f, 1.0f, 0.0f};

    std::array<double, 3> second_ref_dir = {1.0f, 0.0f, 0.0f};

    double radius = -1.0f;

    std::string_view output_geodesic_attribute_name = "@geodesic_distance";

    std::string_view output_polar_angle_attribute_name = "@polar_angle";
};

struct LA_GEODESIC_API SingleSourceGeodesicResult
{
    AttributeId geodesic_distance_id = invalid_attribute_id();

    AttributeId polar_angle_id = invalid_attribute_id();
};

struct LA_GEODESIC_API PointToPointGeodesicOptions
{
    size_t source_facet_id = 0;

    size_t target_facet_id = 0;

    std::array<double, 2> source_facet_bc = {0.0f, 0.0f};

    std::array<double, 2> target_facet_bc = {0.0f, 0.0f};
};

struct LA_GEODESIC_API PointToPointGeodesicPathOptions
{
    size_t source_facet_id = 0;

    size_t target_facet_id = 0;

    std::array<double, 2> source_facet_bc = {0.0f, 0.0f};

    std::array<double, 2> target_facet_bc = {0.0f, 0.0f};
};
 

template <typename Scalar, typename Index>
struct GeodesicPathResult
{
    std::vector<std::array<Scalar, 3>> points;

    std::vector<Index> facet_ids;
};

template <typename Scalar, typename Index>
class GeodesicEngine
{
public:
    using Mesh = SurfaceMesh<Scalar, Index>;
 
public:
public:
    explicit GeodesicEngine(Mesh& mesh);

    virtual ~GeodesicEngine() = default;

    virtual SingleSourceGeodesicResult single_source_geodesic(
        const SingleSourceGeodesicOptions& options) = 0;

    virtual Scalar point_to_point_geodesic(const PointToPointGeodesicOptions& options);

    virtual GeodesicPathResult<Scalar, Index> point_to_point_geodesic_path(
        const PointToPointGeodesicPathOptions& options);
 
protected:
    const Mesh& mesh() const { return m_mesh.get(); }
    Mesh& mesh() { return m_mesh.get(); }
 
private:
    std::reference_wrapper<Mesh> m_mesh; 
};
 
} // namespace lagrange::geodesic