geom_algorithms_test_common.h

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/*
                          Aleph_w
 
  Data structures & Algorithms
  version 2.0.0b
  https://github.com/lrleon/Aleph-w
 
  This file is part of Aleph-w library
 
  Copyright (c) 2002-2026 Leandro Rabindranath Leon
 
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  of 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
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  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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*/
 
#ifndef ALEPH_TEST_GEOM_ALGORITHMS_TEST_COMMON_H
#define ALEPH_TEST_GEOM_ALGORITHMS_TEST_COMMON_H
 
#include <gtest/gtest.h>
#include <geom_algorithms.H>
#include <ah-errors.H>
#include "geometry_visual_golden.h"
 
namespace
{
  [[maybe_unused]] bool polygon_contains_vertex(const Polygon & poly, const Point & p)
  {
    if (poly.size() == 0)
      return false;
 
    for (Polygon::Vertex_Iterator it(poly); it.has_curr(); it.next_ne())
      if (it.get_current_vertex() == p)
        return true;
 
    return false;
  }
 
  [[maybe_unused]] bool matches_unordered_pair(const Point & a, const Point & b,
                                               const Point & u, const Point & v)
  {
    return (a == u and b == v) or (a == v and b == u);
  }
 
  struct TriKey
  {
    size_t a; 
    size_t b; 
    size_t c; 
  };
 
  [[maybe_unused]] void sort3(size_t & a, size_t & b, size_t & c)
  {
    if (a > b)
      {
        const size_t t = a;
        a = b;
        b = t;
      }
    if (b > c)
      {
        const size_t t = b;
        b = c;
        c = t;
      }
    if (a > b)
      {
        const size_t t = a;
        a = b;
        b = t;
      }
  }
 
  [[maybe_unused]] Array<TriKey>
  canonical_triangles(const DelaunayTriangulationBowyerWatson::Result & r)
  {
    Array<TriKey> out;
    out.reserve(r.triangles.size());
    for (size_t i = 0; i < r.triangles.size(); ++i)
      {
        size_t a = r.triangles(i).i;
        size_t b = r.triangles(i).j;
        size_t c = r.triangles(i).k;
        sort3(a, b, c);
        out.append(TriKey{a, b, c});
      }
 
    quicksort_op(out, [](const TriKey & x, const TriKey & y)
                   {
                     if (x.a != y.a)
                       return x.a < y.a;
                     if (x.b != y.b)
                       return x.b < y.b;
                     return x.c < y.c;
                   });
    return out;
  }
 
  [[maybe_unused]] Point circumcenter_of(const Point & a, const Point & b, const Point & c)
  {
    const Geom_Number & ax = a.get_x();
    const Geom_Number & ay = a.get_y();
    const Geom_Number & bx = b.get_x();
    const Geom_Number & by = b.get_y();
    const Geom_Number & cx = c.get_x();
    const Geom_Number & cy = c.get_y();
 
    const Geom_Number a2 = ax * ax + ay * ay;
    const Geom_Number b2 = bx * bx + by * by;
    const Geom_Number c2 = cx * cx + cy * cy;
 
    const Geom_Number d = ax * (by - cy) + bx * (cy - ay) + cx * (ay - by);
    const Geom_Number den = d + d;
 
    ah_domain_error_if(den == 0)
      << "circumcenter_of: collinear triangle (zero area)";
 
    return {
          (a2 * (by - cy) + b2 * (cy - ay) + c2 * (ay - by)) / den,
          (a2 * (cx - bx) + b2 * (ax - cx) + c2 * (bx - ax)) / den
        };
  }
 
  [[maybe_unused]] Geom_Number polygon_signed_area(const Polygon & poly)
  {
    return GeomPolygonUtils::signed_double_area(poly) / 2;
  }
 
  [[maybe_unused]] Geom_Number polygon_area(const Polygon & poly)
  {
    Geom_Number a = polygon_signed_area(poly);
    if (a < 0) { a = -a; }
    return a;
  }
 
  [[maybe_unused]] bool is_ccw(const Polygon & poly)
  {
    return GeomPolygonUtils::signed_double_area(poly) > 0;
  }
 
  [[maybe_unused]] Geom_Number triangle_area(const Triangle & t)
  {
    Geom_Number a = t.area();
    if (a < 0) { a = -a; }
    return a;
  }
 
  [[maybe_unused]] bool all_points_inside_or_on(const DynList<Point> & points, const Polygon & hull)
  {
    for (auto it = points.get_it(); it.has_curr(); it.next_ne())
      if (const auto loc = PointInPolygonWinding::locate(hull, it.get_curr());
        loc == PointInPolygonWinding::Location::Outside)
        return false;
    return true;
  }
 
  [[maybe_unused]] bool polygon_is_convex(const Polygon & poly)
  {
    Array<Point> verts;
    verts.reserve(poly.size());
    for (Polygon::Vertex_Iterator it(poly); it.has_curr(); it.next_ne())
      verts.append(it.get_current_vertex());
    return GeomPolygonUtils::is_convex(verts);
  }
} // namespace
 
class GeomAlgorithmsTest : public ::testing::Test
{
protected:
  void SetUp() override {}
  void TearDown() override {}
};
 
// Basic triangulation tests
 
#endif // ALEPH_TEST_GEOM_ALGORITHMS_TEST_COMMON_H