如何在C++中获取映射中的值的引用?

我希望我的游戏玩家在与其他实体碰撞时不要移动。 我认为一个解决方案是跟踪游戏中的所有实体,当试图移动时,检查它是否会与其中任何实体发生碰撞。 问题是,当循环向量时,我没有得到实体的引用,而是得到新的值,因此它们有新的ID,我不能再检查ID是否检查。

 // Actor.cpp
Actor::Actor(float x, float y) : x(x), y(y), m_MovementSpeed(1), m_Alive(true) {
    // ...
    EntityTracker::addEntity(*this);
    this->ID = EntityTracker::entityAmount();
}

void Actor::move(float _x, float _y) {
    for (auto& e : EntityTracker::entities()) {
        if (this->ID != e->ID && this->collides(*e)) {
            return;
        }
    }

    this->x = this->x + _x * m_MovementSpeed;
    this->y = this->y + _y * m_MovementSpeed;
    this->m_Sprite.move(_x * m_MovementSpeed, _y * m_MovementSpeed);
}

// EntityTracker.cpp
uint64_t EntityTracker::s_EntityAmount = 0;
std::map<uint64_t, Actor> EntityTracker::s_Entities {};

void EntityTracker::addEntity(const Actor& actor) {
    EntityTracker::s_Entities.insert(std::pair<uint64_t, Actor>(s_EntityAmount, actor));
    s_EntityAmount++;
}

std::vector<Actor*> EntityTracker::entities() {
    std::vector<Actor*> actors;

    for (auto& it : EntityTracker::s_Entities) {
        std::cout << it.second.ID << std::endl;
        std::cout << it.first << std::endl;
        actors.push_back(&it.second);
    }

    return actors;
}

// EntityTracker.h
class EntityTracker {
public:
    static void addEntity(const Actor& actor);
    static bool removeEntity(uint64_t ID);
    static uint64_t entityAmount();
    static std::vector<Actor*> entities();
private:
    static uint64_t s_EntityAmount;
    static std::map<uint64_t, Actor> s_Entities;
};

当我按下一个键时,std::cout's print this:

1571901079888 // actor's internal ID from vector
0 // ID from vector
1571901079888
1
1571901079888
0
...

我该怎么解决这个问题?