cpp-game-engine/engine/test/scene_test.cxx

//
//  scene_test.cxx
//  engine-test
//
//  Created by Sam Jaffe on 7/12/19.
//  Copyright © 2019 Sam Jaffe. All rights reserved.
//

#include <gmock/gmock.h>

#include "game/engine/entity.hpp"
#include "game/engine/game_dispatch.hpp"
#include "game/engine/scene.hpp"

#include "mock_renderer.h"

namespace env {
  void resize_screen(math::vec2i const & size);
}

struct test_scene : engine::scene {
  using engine::scene::scene;

  void update(float) override { check_collisions(); }
  void render() override {}
  void handle_key_event(engine::event::key_event) override {}
  void handle_mouse_event(engine::event::mouse_event) override {}
  bool in_bounds(math::dim2::point c) const { return engine::scene::in_bounds(c); }
  bool in_bounds(engine::collidable * c) const { return engine::scene::in_bounds(c); }

  void add_with(engine::collision_t t, engine::collidable & c) {
    colliders[t].push_back(&c);
  }
  void add_as(engine::collision_t t, engine::collidable & c) {
    collidables[t].push_back(&c);
  }
};

struct mock_collidable : engine::collidable {
  mock_collidable(math::dim2::rectangle bounds)
      : engine::collidable({bounds, bounds, cast<graphics::material>(1), {}}) {}
  MOCK_METHOD1(collide, void(engine::collidable const &));
};

class SceneTest : public testing::Test {
protected:
  void SetUp() override;
  void TearDown() override;

  test_scene & scene() const { return *scene_; }
  engine::game_dispatch & game() const { return *dispatch_; }

  std::shared_ptr<stub_renderer> renderer_;
  std::shared_ptr<engine::game_dispatch> dispatch_;
  std::shared_ptr<test_scene> scene_;
};

void SceneTest::SetUp() {
  renderer_.reset(new stub_renderer);
  math::vec2 screen{{1600.f, 900.f}};
  env::resize_screen(math::vec2i(screen));
  dispatch_.reset(new engine::game_dispatch(renderer_));
  scene_.reset(new test_scene("test", screen, dispatch_));
}

void SceneTest::TearDown() {
  scene_.reset();
  dispatch_.reset();
  renderer_.reset();
}

using testing::Eq;
using testing::Ref;

TEST_F(SceneTest, WillCollideOverlappingObjects) {
  math::dim2::rectangle bnds{{{0.f, 0.f}}, {{1.f, 1.f}}};
  mock_collidable one{bnds}, two{bnds};
  scene().add_with(1, one);
  scene().add_as(1, two);
  EXPECT_CALL(one, collide(Ref(two))).Times(1);
  scene().update(0.f);
}

TEST_F(SceneTest, NonOverlappingDontCollide) {
  mock_collidable one{{{{0.f, 0.f}}, {{1.f, 1.f}}}};
  mock_collidable two{{{{2.f, 2.f}}, {{1.f, 1.f}}}};
  scene().add_with(1, one);
  scene().add_as(1, two);
  EXPECT_CALL(one, collide(Ref(two))).Times(0);
  scene().update(0.f);
}

TEST_F(SceneTest, CollisionIsOneWay) {
  math::dim2::rectangle bnds{{{0.f, 0.f}}, {{1.f, 1.f}}};
  mock_collidable one{bnds}, two{bnds};
  scene().add_with(1, one);
  scene().add_as(1, two);
  EXPECT_CALL(one, collide(Ref(two))).Times(1);
  EXPECT_CALL(two, collide(Ref(one))).Times(0);
  scene().update(0.f);
}

TEST_F(SceneTest, ObjectCannotCollideSelf) {
  math::dim2::rectangle bnds{{{0.f, 0.f}}, {{1.f, 1.f}}};
  mock_collidable one{bnds};
  scene().add_with(1, one);
  scene().add_as(1, one);
  EXPECT_CALL(one, collide(Ref(one))).Times(0);
  scene().update(0.f);
}

TEST_F(SceneTest, CollisionMatchesAsWithKeys) {
  math::dim2::rectangle bnds{{{0.f, 0.f}}, {{1.f, 1.f}}};
  mock_collidable one{bnds}, two{bnds}, three{bnds};
  scene().add_with(2, one);
  scene().add_as(1, two);
  scene().add_as(2, three);
  EXPECT_CALL(one, collide(Ref(two))).Times(0);
  EXPECT_CALL(one, collide(Ref(three))).Times(1);
  scene().update(0.f);
}

TEST_F(SceneTest, ObjectCanBeInMultipleCollidesWithGroups) {
  math::dim2::rectangle bnds{{{0.f, 0.f}}, {{1.f, 1.f}}};
  mock_collidable one{bnds}, two{bnds}, three{bnds};
  scene().add_with(1, one);
  scene().add_with(2, one);
  scene().add_as(1, two);
  scene().add_as(2, three);
  EXPECT_CALL(one, collide(Ref(two))).Times(1);
  EXPECT_CALL(one, collide(Ref(three))).Times(1);
  scene().update(0.f);
}

TEST_F(SceneTest, ObjectCanBeInMultipleCollidableAsGroups) {
  math::dim2::rectangle bnds{{{0.f, 0.f}}, {{1.f, 1.f}}};
  mock_collidable one{bnds}, two{bnds}, three{bnds};
  scene().add_with(1, one);
  scene().add_with(2, three);
  scene().add_as(1, two);
  scene().add_as(2, two);
  EXPECT_CALL(one, collide(Ref(two))).Times(1);
  EXPECT_CALL(three, collide(Ref(two))).Times(1);
  scene().update(0.f);
}

// TODO: Solve double-collision bug?
TEST_F(SceneTest, DoubleCollisionCanOccur) {
  math::dim2::rectangle bnds{{{0.f, 0.f}}, {{1.f, 1.f}}};
  mock_collidable one{bnds}, two{bnds};
  scene().add_with(1, one);
  scene().add_with(2, one);
  scene().add_as(1, two);
  scene().add_as(2, two);
  EXPECT_CALL(one, collide(Ref(two))).Times(2);
  scene().update(0.f);
}

struct BoundsTest : SceneTest, testing::WithParamInterface<math::vec2> {};

TEST_F(BoundsTest, BoundsCheckIsPointInScreenZone) {
  // Confirm that the size is as expected...
  EXPECT_THAT(scene().size(), Eq(make_vector(1600.f, 900.f)));
  
  // Lower-Left Corner
  EXPECT_FALSE(scene().in_bounds(make_vector(  -1.f,   0.f)));
  EXPECT_FALSE(scene().in_bounds(make_vector(   0.f,  -1.f)));
  EXPECT_TRUE(scene().in_bounds(make_vector(0.f, 0.f)));
  // Lower-Right Corner
  EXPECT_FALSE(scene().in_bounds(make_vector(1600.f,  -1.f)));
  EXPECT_FALSE(scene().in_bounds(make_vector(1601.f,   0.f)));
  EXPECT_TRUE(scene().in_bounds(make_vector(1600.f,   0.f)));
  // Upper-Right Corner
  EXPECT_FALSE(scene().in_bounds(make_vector(1601.f, 900.f)));
  EXPECT_FALSE(scene().in_bounds(make_vector(1600.f, 901.f)));
  EXPECT_TRUE(scene().in_bounds(make_vector(1600.f, 900.f)));
  // Upper-Left Corner
  EXPECT_FALSE(scene().in_bounds(make_vector(   0.f, 901.f)));
  EXPECT_FALSE(scene().in_bounds(make_vector(  -1.f, 900.f)));
  EXPECT_TRUE(scene().in_bounds(make_vector(   0.f, 900.f)));
}

TEST_P(BoundsTest, BoundsCheckOnCollidableIsAnyPointInBounds) {
  math::dim2::square bounds = {GetParam(), 2.f};
  engine::collidable collide{{{}, bounds, cast<graphics::material>(1), {}}};
  
  EXPECT_TRUE(scene().in_bounds(&collide));
}

INSTANTIATE_TEST_CASE_P(Collidable, BoundsTest,
                        ::testing::Values(make_vector(  -1.f,  -1.f),
                                          make_vector(1599.f,  -1.f),
                                          make_vector(1599.f, 899.f),
                                          make_vector(  -1.f, 899.f)));