polygon.hpp

/*
 Copyright (c) 2025 ETIB Corporation
 
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 this software and associated documentation files (the "Software"), to deal in
 the Software without restriction, including without limitation the rights to
 use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
 of the Software, and to permit persons to whom the Software is furnished to do
 so, subject to the following conditions:
 
 The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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 */
 
#pragma once
 
#include <cmath>
#include <vector>
 
#include "primitive.hpp"
#include "vertex.hpp"
#include "point.hpp"
 
class Polygon : public Primitive {
private:
  std::vector<Vertex> _vertices; 
  Point _rotation;    
  Point _translation; 
 
public:
  Polygon(void) : Primitive(), _vertices(), _rotation(), _translation() {}
 
  Polygon(const std::vector<Vertex> &vertices,
          const Point &rotation = Point())
      : Primitive(), _vertices(vertices), _rotation(rotation), _translation() {}
 
  Polygon(const std::vector<Point> &points, const Point &rotation = Point())
      : Primitive(), _rotation(rotation), _translation() {
    _vertices.clear();
    for (const auto &p : points) {
      _vertices.emplace_back(p, Color(1.0f, 1.0f, 1.0f));
    }
  }
 
  ~Polygon(void) override = default;
 
  Polygon &addVertex(const Vertex &vertex) {
    _vertices.push_back(vertex);
    return *this;
  }
 
  const std::vector<Vertex> &getVertices(void) const { return _vertices; }
 
  const Point &getRotation(void) const { return _rotation; }
 
  const Point &getTranslation(void) const { return _translation; }
 
  Polygon &setRotation(const Point &rotation) {
    _rotation = rotation;
    return *this;
  }
 
  Polygon &setTranslation(const Point &translation) {
    _translation = translation;
    return *this;
  }
 
  void setVertices(const std::vector<Vertex> &vertices) { _vertices = vertices; }
 
  std::vector<Point> getPoints(void) const {
    std::vector<Point> pts;
    pts.reserve(_vertices.size());
    for (const auto &v : _vertices) {
      pts.push_back(v.position);
    }
    return pts;
  }
 
  // /**
  //  * @brief Calculates the surface normal for this polygon (assuming planar
  //  * polygon)
  //  *
  //  * Uses the first three points to calculate the normal vector using cross
  //  * product. This is useful for 3D rendering, lighting calculations, and
  //  * back-face culling.
  //  *
  //  * @return Point representing the normalized surface normal (0,0,0) if less
  //  * than 3 points
  //  */
  // Point calculateNormal(void) const {
  //   if (_points.size() < 3) {
  //     return Point(0, 0, 0);
  //   }
 
  //   // Get vectors from first point to second and third points
  //   Point v1(_points[1].x() - _points[0].x(), _points[1].y() -
  //   _points[0].y(),
  //            _points[1].z() - _points[0].z());
 
  //   Point v2(_points[2].x() - _points[0].x(), _points[2].y() -
  //   _points[0].y(),
  //            _points[2].z() - _points[0].z());
 
  //   // Calculate cross product to get normal
  //   float nx = v1.y() * v2.z() - v1.z() * v2.y();
  //   float ny = v1.z() * v2.x() - v1.x() * v2.z();
  //   float nz = v1.x() * v2.y() - v1.y() * v2.x();
 
  //   // Normalize the vector
  //   float length = std::sqrt(nx * nx + ny * ny + nz * nz);
  //   if (length > 0.0001f) { // Avoid division by zero
  //     return Point(nx / length, ny / length, nz / length);
  //   }
 
  //   return Point(0, 0, 1); // Default to Z-up if calculation fails
  // }
 
  // /**
  //  * @brief Calculates the centroid (geometric center) of the polygon
  //  *
  //  * @return Point representing the centroid of all vertices
  //  */
  // Point calculateCentroid(void) const {
  //   if (_points.empty()) {
  //     return Point(0, 0, 0);
  //   }
 
  //   float x = 0, y = 0, z = 0;
  //   for (const auto &point : _points) {
  //     x += point.x();
  //     y += point.y();
  //     z += point.z();
  //   }
 
  //   float count = static_cast<float>(_points.size());
  //   return Point(x / count, y / count, z / count);
  // }
};