Overload a function with a derived class argument if you only have a pointer to the base class in C++

Question

I have seen people using containers of pointers to the base class to hold groups of objects which share the same virtual functions. Is it possible to use overloaded functions of the derived class with these base class pointers. It is hard to explain what I mean but (I think) easy to show with code

class PhysicsObject // A pure virtual class
{
    // Members of physics object
    // ...
};

class Circle : public PhysicsObject
{
    // Members of circle
    // ...
};

class Box : public PhysicsObject
{
    // Members of box
    // ...
};

// Overloaded functions (Defined elsewhere)
void ResolveCollision(Circle& a, Box& b);
void ResolveCollision(Circle& a, Circle& b);
void ResolveCollision(Box& a, Box& b);

int main()
{
    // Container to hold all our objects 
    std::vector<PhysicsObject*> objects;

    // Create some circles and boxes and add to objects container
    // ...

    // Resolve any collisions between colliding objects
    for (auto& objA : objects)
        for (auto& objB : objects)
            if (objA != objB)
                ResolveCollision(*objA, *objB); // !!! Error !!! Can't resolve overloaded function
}

My first idea was to make these functions be virtual class members also (shown below) but I quickly realised that it has exactly the same issue.

class Circle;
class Box;
class PhysicsObject // A pure virtual class
{
    virtual void ResolveCollision(Circle& a) = 0;
    virtual void ResolveCollision(Box& a) = 0;
    // Members of physics object
    // ...
};

class Box;
class Circle : public PhysicsObject
{
    void ResolveCollision(Circle& a);
    void ResolveCollision(Box& a);
    // Members of circle
    // ...
};

class Circle;
class Box : public PhysicsObject
{
    void ResolveCollision(Circle& a);
    void ResolveCollision(Box& a);
    // Members of box
    // ...
};

From googling the problem it seems like possibly it can be solved using casting but I can't figure out how to find the correct type to cast to (also it is ugly). I suspect I am asking the wrong question and there is a better way to structure my code which sidesteps this problem and achieves the same result.

Answer 1

With double dispatch, it would be something like:

class Circle;
class Box;

// Overloaded functions (Defined elsewhere)
void ResolveCollision(Circle& a, Box& b);
void ResolveCollision(Circle& a, Circle& b);
void ResolveCollision(Box& a, Box& b);
class PhysicsObject // A pure virtual class
{
public:
    virtual ~PhysicsObject() = default;

    virtual void ResolveCollision(PhysicsObject&) = 0;
    virtual void ResolveBoxCollision(Box&) = 0;
    virtual void ResolveCircleCollision(Circle&) = 0;
};

class Circle : public PhysicsObject
{
public:
    void ResolveCollision(PhysicsObject& other) override { return other.ResolveCircleCollision(*this); }
    void ResolveBoxCollision(Box& box) override { ::ResolveCollision(*this, box);}
    void ResolveCircleCollision(Circle& circle) override { ::ResolveCollision(*this, circle);}
    // ...
};

class Box : public PhysicsObject
{
public:
    void ResolveCollision(PhysicsObject& other) override { return other.ResolveBoxCollision(*this); }
    void ResolveBoxCollision(Box& box) override { ::ResolveCollision(box, *this);}
    void ResolveCircleCollision(Circle& circle) override { ::ResolveCollision(circle, *this);}
    // ...
};