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 "game/math/shape.hpp"

#include <testing/xcode_gtest_helper.h>

#include "test_printers.h"

using namespace math::dim2;
using namespace testing;

struct FromOriginTest : 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), 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_SUITE_P(LineIntersection, FromOriginTest,
                         ValuesIn(point_pairs));

struct UnitLineTest : TestWithParam<point> {};

TEST(LineTest, UnitLineHasLengthOne) {
  line const unit{{{0, 0}}, {{1, 0}}};
  EXPECT_THAT(unit.length(), Eq(1));
}

TEST(LineTest, ParallelLinesHaveSameSlope) {
  line const lhs{{{0, 0}}, {{1, 0}}};
  line const rhs{{{-1, 0}}, {{-2, 0}}};
  EXPECT_TRUE(math::lines::parallel(lhs, rhs));
}

TEST_P(UnitLineTest, 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), Eq(expected));
}

TEST_P(UnitLineTest, OrthoOnIntersectionY) {
  line const ln{{{0, 0}}, {{0, 1}}};
  point const pt = GetParam();
  line const expected{pt, {{pt[0], 0}}};
  EXPECT_THAT(math::lines::orthogonal(ln, pt), 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_SUITE_P(LineOrthogonal, UnitLineTest, ValuesIn(x_orthos));

struct DiagonalTest : 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), 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_SUITE_P(LineOrthogonal, DiagonalTest, ValuesIn(diag_orthos));

struct QuadTest : TestWithParam<std::tuple<float, float>> {};

TEST_P(QuadTest, SquareProducesQuadWithCornersAtX) {
  float x = std::get<0>(GetParam());
  square const square{{{0, 0}}, x};
  quad const expected{{{0, 0}}, {{x, 0}}, {{x, x}}, {{0, x}}};
  EXPECT_THAT(quad(square), Eq(expected));
}

TEST_P(QuadTest, SquareProducesRectangleWithXX) {
  float side = std::get<0>(GetParam());
  square const square{{{0, 0}}, side};
  EXPECT_THAT(rectangle(square).origin, Eq(square.origin));
  EXPECT_THAT(rectangle(square).size[0], Eq(side));
  EXPECT_THAT(rectangle(square).size[0], Eq(side));
}

TEST_P(QuadTest, OffsetSquareProducesRectangleWithXX) {
  float side = std::get<0>(GetParam());
  square const square{{{1, 1}}, side};
  EXPECT_THAT(rectangle(square).origin, Eq(square.origin));
  EXPECT_THAT(rectangle(square).size[0], Eq(side));
  EXPECT_THAT(rectangle(square).size[0], Eq(side));
}

TEST_P(QuadTest, RectProducesQuadWithCornersAtXY) {
  float x = std::get<0>(GetParam());
  float y = std::get<1>(GetParam());
  rectangle const square{{{0, 0}}, {{x, y}}};
  quad const expected{{{0, 0}}, {{x, 0}}, {{x, y}}, {{0, y}}};
  EXPECT_THAT(quad(square), Eq(expected));
}

INSTANTIATE_TEST_SUITE_P(Upcast, QuadTest,
                         Combine(Values(0.5, 1.0, 1.5, 2.0),
                                 Values(0.5, 1.0, 1.5, 2.0)));