cpp-game-engine/math/test/shape_test.cxx

//
//  shape_test.cxx
//  math
//
//  Created by Sam Jaffe on 5/4/19.
//  Copyright © 2019 Sam Jaffe. All rights reserved.
//

#include <gmock/gmock.h>

#include "game/math/shape.hpp"

namespace math { namespace vector {
  std::ostream & operator<<(std::ostream & os, math::vec2 const & p) {
    return os << '[' << p[0] << ',' << p[1] << ']';
  }
} }
namespace math { namespace dim2 {
  bool operator==(line const & lhs, line const & rhs) {
    return lhs.first == rhs.first && lhs.second == rhs.second;
  }
  std::ostream & operator<<(std::ostream & os, line const & l) {
    return os << '[' << l.first << ',' << l.second << ']';
  }
} }

using namespace math::dim2;

struct FromOriginTest : testing::TestWithParam<line> {};

TEST_P(FromOriginTest, IntersectsAtOrigin) {
  line l1 = { GetParam().first, {{0, 0}} };
  line l2 = { {{0, 0}}, GetParam().second };
  
  EXPECT_THAT(math::lines::intersection(l1, l2),
              testing::Eq(point{{0, 0}}));
}

std::vector<line> const point_pairs{
  {{{1, 1}}, {{0, 0}}},   // 0 length
  {{{1, 1}}, {{1, 0}}},   // -45deg
  {{{1, 1}}, {{0, 1}}},   // +45deg
  {{{1, 1}}, {{1, 1}}},   // +0deg
  {{{1, 1}}, {{2, 1}}},   // -18deg (approx)
  {{{1, 1}}, {{1, 2}}},   // +18deg (approx)
  {{{2, 3}}, {{1, 2}}},   //
  {{{1, 1}}, {{-1,  0}}}, // +135deg
  {{{1, 1}}, {{ 0, -1}}}, // -135deg
  {{{1, 1}}, {{-1, -1}}}, // +180deg
  {{{1, 1}}, {{ 1, -1}}}, // +90deg
  {{{1, 1}}, {{-1,  1}}}, // -90deg
};

INSTANTIATE_TEST_CASE_P(LineIntersection, FromOriginTest,
                        testing::ValuesIn(point_pairs));

struct XUnitTest : testing::TestWithParam<point> {};

TEST_P(XUnitTest, OrthoOnIntersection) {
  line const ln{{{0, 0}}, {{1, 0}}};
  point const pt = GetParam();
  line const expected{pt, {{pt[0], 0}}};
  EXPECT_THAT(math::lines::orthogonal(ln, pt),
              testing::Eq(expected));
}

std::vector<point> x_orthos{
  {{0, 1}}, {{1, 1}}, {{1, 0}}, {{-1, 0}}, {{0, -1}}, {{-1, -1}},
  {{0, 2}}, {{2, 2}}, {{2, 0}}, {{-2, 0}}, {{0, -2}}, {{-2, -2}},
  {{2, 1}}, {{1, 2}}, {{-2, 1}}, {{-1, 2}}, {{1, -2}}, {{2, -1}}
};

INSTANTIATE_TEST_CASE_P(LineOrthogonal, XUnitTest,
                        testing::ValuesIn(x_orthos));

struct DiagonalTest : testing::TestWithParam<std::pair<point, float>> {};

TEST_P(DiagonalTest, OrthoOnIntersection) {
  line const ln{{{0, 0}}, {{1, 1}}};
  point const pt = GetParam().first;
  line const expected{pt, {{GetParam().second, GetParam().second}}};
  EXPECT_THAT(math::lines::orthogonal(ln, pt),
              testing::Eq(expected));
}

std::vector<std::pair<point, float>> diag_orthos{
  {{{0, 1}}, 0.5f}, {{{1, 1}}, 1.f}, {{{1, 0}}, 0.5f},
  {{{-1, 0}}, -0.5f}, {{{0, -1}}, -0.5f}, {{{-1, -1}}, -1.f},
  {{{0, 2}}, 1.f}, {{{2, 2}}, 2.f}, {{{2, 0}}, 1.f},
  {{{-2, 0}}, -1.f}, {{{0, -2}}, -1.f}, {{{-2, -2}}, -2.f},
  {{{2, 1}}, 1.5f}, {{{1, 2}}, 1.5f}, {{{-2, 1}}, -0.5f},
  {{{-1, 2}}, 0.5f}, {{{1, -2}}, -0.5f}, {{{2, -1}}, 0.5f}
};

INSTANTIATE_TEST_CASE_P(LineOrthogonal, DiagonalTest,
                        testing::ValuesIn(diag_orthos));