AggregateSceneElementInGraphObserver.h

#pragma once

#include "ISceneElementInGraphObserver.h"
#include <vector>

namespace Eegeo
{
    namespace Rendering
    {
        namespace Scene
        {
            // Scene elements only have a single observer.  Adding an array of observers to every scene element was thought to be a potential
            // performance risk, so this type has been added to help the situation where we need multiple observers to be informed of something
            // being added to or removed from the scenegraph.  At the time of writing this only applies to custom landmarks on Unity.
            template<typename T>
            class AggregateSceneElementInGraphObserver : public ISceneElementInGraphObserver<T>
            {
            public:

                AggregateSceneElementInGraphObserver(const std::vector<ISceneElementInGraphObserver<T>*>& observers)
                    : m_observers(observers)
                {

                }

                virtual void OnAddedToSceneGraph(SceneElement<T>* resource) override
                {
                    for (auto pObserver : m_observers)
                    {
                        pObserver->OnAddedToSceneGraph(resource);
                    }
                }

                virtual void OnRemovedFromSceneGraph(SceneElement<T>* resource) override
                {
                    for (auto pObserver : m_observers)
                    {
                        pObserver->OnRemovedFromSceneGraph(resource);
                    }
                }

            private:

                std::vector<ISceneElementInGraphObserver<T>*> m_observers;
            };
        }
    }
}