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Graphics / Storing specific shapes(circle, rect) in a pointer to sf::Shape

« on: November 10, 2018, 03:23:46 am »

I have a class called Actor which is intended to represent both rectangles and circles in my application. The class contains a member sf::Shape *mShape in which either a new sf::CircleShape or sf::RectShape is stored on construction of the object. My first question would be if this is actually the best approach or if I should make two extra classes for rectangles and circles that derive from Actor. I thought about this, but I first wanted to try it with one class since I didn't want to bloat the code with so much classes if I can avoid it, and also its easier to just loop through a vector of one class type. This approach worked fine until I needed to pass the mShape of an Actor to a function that specifically requires a pointer to sf::CircleShape and sf::RectangleShape. Here is some code:

class Actor : public sf::Transformable, public sf::Drawable {
    public:
    sf::Shape* mShape;

    Actor(float radius) {
        mShape = new sf::CircleShape(radius);
        //do stuff
    }

    Actor(float width, float height) {
        mShape = new sf::RectangleShape(sf::Vector2f(width, height));
        //do stuff
    }

    private:
    virtual void draw(sf::RenderTarget& target, sf::RenderStates states) const {
        target.draw(*mShape, states);
    }
};

void foo(sf::CircleShape* circle, sf::RectangleShape* rect) {
    //do stuff
}

void moveActors() {
    foo(actors[0].mShape, actors[1].mShape);  
}
 

It doesn't work how I intend it to, which may be obvious to someone who has a deeper understanding of pointers and class inheritance than me. The compiler complains that conversion from sf::Shape* to sf::CircleShape* or sf::RectangleShape* is invalid.So my second question would be I should best go about this. I realize that the problem may lie in my understanding of C++ and pointers, but I hope it's specific enough to SFML that I can ask here.