Messages

16

Graphics / Which function to overload in class derived from sf::Sprite?

« on: January 02, 2012, 06:44:45 pm »

None, sf::Sprite isn't intended to be used as a base class. In order to create custom drawable entities, you should rather derive directly from sf::Drawable and override Draw().

And generally, a tank or a gun usually have a sprite (not are one). Aggregation also brings less coupling than inheritance...

Then is there any dirty hack for that?

Because I want the tank to manipulate both itself and the gun (i think it's rightly even for real-life )
And I don't want to write lots of code when deriving from sf::Drawable...

I think there must be solution... because the framework is very unflexible then... Or just I can't get it philosophy

17

Graphics / Which function to overload in class derived from sf::Sprite?

« on: January 02, 2012, 05:51:49 pm »

Hi all.
Which function must I overload in my class derived from sf::Sprite to keep that drawing behavior for RenderWindow::Draw() function just like the same as for Sprite. you know...

I mean how to keep behavior of my class like that

Code: [Select]

sf::RenderWindow App(/*init there*/);
sf::Sprite MySprite(); //let's count this sprite as fully initialized

App.Draw(MySprite);

But for my derived class.
To make the discussion more objective here is my class(es) code:

Code: [Select]

class Gun : public sf::Sprite
{
 public:
    Gun(const sf::Vector2f& Position, float Rotation=0, std::string texture=Options::Gun::Texture)
    {
        Texture.LoadFromFile(texture);
        sf::Sprite::SetImage(Texture);
        sf::Sprite::SetPosition(Position);
        sf::Sprite::SetCenter(Options::Gun::Center);
        sf::Sprite::SetRotation(Rotation);
    }
    void AimAt(const sf::Vector2f& Mouse)
    {
        sf::Vector2f Position = sf::Sprite::GetPosition();
        float angle = std::atan2(Mouse.y - Position.y, Mouse.x - Position.x)*rad;  // угол наклона

        sf::Sprite::SetRotation(270 - angle);
    }
 private:
    sf::Image Texture;
    float VecLength(const sf::Vector2f& first, const sf::Vector2f& second)
    {
        return std::sqrt (std::pow( (second.x-first.x) ,2) + std::pow( (second.y-first.y) ,2));
    }
};

class Tank : public sf::Sprite
{
 public:
    Tank(const sf::Vector2f& Position, float Rotation=0, std::string texture=Options::Tank::Texture) : Cannon(Options::Tank::GunPlace, Rotation)
    {
        Texture.LoadFromFile(texture);
        sf::Sprite::SetImage(Texture);
        sf::Sprite::SetPosition(Position);
        sf::Vector2f PureCenter(Texture.GetWidth()/2 , Texture.GetHeight()/2);
        sf::Sprite::SetCenter(PureCenter);
        sf::Sprite::SetRotation(Rotation);
    }
    Gun& GetGun(void)
    {
        return Cannon;
    }
    void Simulate(const sf::Vector2f& Mouse)
    {

    }
 private:
    Gun Cannon;
    sf::Image Texture;
};


As you can see I need my Tank class to Draw both itself's sprite and the cannon's sprite at the request of drawning the Tank sprite...

So which functions and how must I overload?
I guess it's some of Sprite::Draw() or Sprite::Render() functions.

Forehand thank you. And sorry for my bad English =(