2D scene graph

class GNode : public enable_shared_from_this<GNode>
{
public:
    Vec2f mLocalPosition { 0, 0 };
    Vec2f mGlobalPosition { 0, 0 };
    Vec2f mLocalScale { 1, 1 };
    Vec2f mGlobalScale { 1, 1 };
    float mLocalRotation { 0 };
    float mGlobalRotation { 0 };
    weak_ptr<GNode> mParent;
    vector<shared_ptr<GNode>> mChildren;
    void CalculateTransforms()
    {
        if ( auto parent = mParent.lock() )
        {
            mGlobalRotation = parent->mGlobalRotation + mLocalRotation;
            mGlobalScale = parent->mGlobalScale * mLocalScale;
            mGlobalPosition = parent->mGlobalPosition + Math::RotateVector( mLocalPosition * parent->mGlobalScale, parent->mGlobalRotation );
        }
        else
        {
            mGlobalPosition = mLocalPosition;
            mGlobalRotation = mLocalRotation;
            mGlobalScale = mLocalScale;
        }

        for ( auto & child : mChildren )
        {
            child->CalculateTransforms();
        }
    }
    void AttachTo( const shared_ptr<GNode> & parent )
    {
        mParent = parent;
        parent->mChildren.push_back( shared_from_this() );
    }
};