polygon.hpp

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/*
  Wizard Engine
  Copyright (C) 2023-2024 Zana Domán
 
  This software is provided 'as-is', without any express or implied
  warranty. In no event will the authors be held liable for any damages
  arising from the use of this software.
 
  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:
 
  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
 
#ifndef WIZARD_ENGINE_POLYGON_HPP
#define WIZARD_ENGINE_POLYGON_HPP
 
#include <wizard_engine/component.hpp>
#include <wizard_engine/export.hpp>
#include <wizard_engine/math.hpp>
 
namespace wze {
class polygon final : public component {
  private:
    std::vector<std::pair<float, float>> _shape;
    float _shape_radius;
    std::vector<std::pair<float, float>> _points;
    float _points_radius;
    float _x;
    float _y;
    float _angle;
    float _scale;
    std::array<float, 4> _transformation_matrix;
    float _x_offset;
    float _y_offset;
    float _angle_offset;
    bool _attach_x;
    bool _attach_y;
    bool _attach_angle;
    bool _x_angle_lock;
    bool _y_angle_lock;
 
    void update_x();
 
    void update_y();
 
    [[nodiscard]] float circumradius() const;
 
    [[nodiscard]] std::pair<float, float>
    project(std::pair<float, float> const& vector) const;
 
  public:
    [[nodiscard]] std::vector<std::pair<float, float>> const& shape() const;
 
    [[nodiscard]] float shape_radius() const;
 
    [[nodiscard]] std::vector<std::pair<float, float>> const& points() const;
 
    [[nodiscard]] float points_radius() const;
 
    [[nodiscard]] float x() const;
 
    void set_x(float x) final;
 
    [[nodiscard]] float y() const;
 
    void set_y(float y) final;
 
    [[nodiscard]] float angle() const;
 
    void set_angle(float angle) final;
 
    [[nodiscard]] float scale() const;
 
    void set_scale(float scale);
 
    [[nodiscard]] std::array<float, 4> const& transformation_matrix() const;
 
    [[nodiscard]] float x_offset() const final;
 
    void set_x_offset(float x_offset);
 
    [[nodiscard]] float y_offset() const final;
 
    void set_y_offset(float y_offset);
 
    [[nodiscard]] float angle_offset() const final;
 
    void set_angle_offset(float angle_offset);
 
    [[nodiscard]] bool attach_x() const final;
 
    void set_attach_x(bool attach_x);
 
    [[nodiscard]] bool attach_y() const final;
 
    void set_attach_y(bool attach_y);
 
    [[nodiscard]] bool attach_angle() const final;
 
    void set_attach_angle(bool attach_angle);
 
    [[nodiscard]] bool x_angle_lock() const final;
 
    void set_x_angle_lock(bool x_angle_lock);
 
    [[nodiscard]] bool y_angle_lock() const final;
 
    void set_y_angle_lock(bool y_angle_lock);
 
    explicit polygon(std::vector<std::pair<float, float>> const& shape =
                         {{0, 0}, {0, 0}, {0, 0}},
                     float x = 0, float y = 0, float angle = 0, float scale = 1,
                     float x_offset = 0, float y_offset = 0,
                     float angle_offset = 0, bool attach_x = true,
                     bool attach_y = true, bool attach_angle = true,
                     bool x_angle_lock = true, bool y_angle_lock = true);
 
    [[nodiscard]] bool inside(float x, float y) const;
 
    template <typename T>
    [[nodiscard]] std::enable_if_t<
        std::is_same_v<T, bool> || std::is_same_v<T, float>, T>
    overlap(polygon const& other) const {
        polygon const* polygon1;
        polygon const* polygon2;
        T state;
        size_t i;
        std::vector<std::pair<float, float>>::const_iterator point1;
        std::vector<std::pair<float, float>>::const_iterator point2;
        std::pair<float, float> normal;
        std::pair<float, float> projection1;
        std::pair<float, float> projection2;
 
        if (points_radius() + other.points_radius() <
            math::length(other.x() - x(), other.y() - y())) {
            return std::is_same_v<T, bool> ? false : 0;
        }
 
        polygon1 = this;
        polygon2 = &other;
        state =
            std::is_same_v<T, bool> ? true : std::numeric_limits<float>::max();
 
        for (i = 0; i != 2; ++i) {
            for (point1 = polygon1->points().begin(),
                point2 = polygon1->points().begin() + 1;
                 point1 != polygon1->points().end(); ++point1, ++point2) {
                if (point2 == polygon1->points().end()) {
                    point2 = polygon1->points().begin();
                }
 
                normal = math::normal(point2->first - point1->first,
                                      point2->second - point1->second);
                if constexpr (std::is_same_v<T, float>) {
                    normal = std::apply(math::normalize, normal);
                }
                projection1 = polygon1->project(normal);
                projection2 = polygon2->project(normal);
 
                if (projection2.second < projection1.first ||
                    projection1.second < projection2.first) {
                    return std::is_same_v<T, bool> ? false : 0;
                }
 
                if constexpr (std::is_same_v<T, float>) {
                    state = std::min(
                        std::min(projection1.second, projection2.second) -
                            std::max(projection1.first, projection2.first),
                        state);
                }
            }
 
            polygon1 = &other;
            polygon2 = this;
        }
 
        return state;
    }
};
} /* namespace wze */
 
#endif /* WIZARD_ENGINE_POLYGON_HPP */