fysxasteroids/engine/OverlayBase.h

#ifndef OVERLAYBASE
#define OVERLAYBASE

#include <boost/shared_ptr.hpp>

#include <SDL/SDL.h>
#include <map>
#include <list>

namespace Engine {

class ModelBase;

/** \brief Base class for user-interfaces
 *
 * An Overlay is something that is displayed above the game graphics e.g.
 * such as a health indicator for the player or the user interface such as
 * the menu or the console. The member function OverlayBase::Draw() is used
 * for drawing and also receives input such as key press events and mouse
 * button events.
 *
 * The function OverlayBase::Init() is called by the OverlayManager class and
 * allows the OverlayBase to load its ressources.
 */
class OverlayBase {
	public:
		OverlayBase () {};
		virtual ~OverlayBase() {};

		/** \brief This function gets called by the OverlayManager class */
		virtual void Init() {};

		virtual bool OnKeyDown (const SDL_keysym &keysym) { return false; };
		virtual bool OnKeyUp (const SDL_keysym &keysym) { return false; };
		virtual bool OnMouseButtonUp (Uint8 button, Uint16 xpos, Uint16 ypos) { return false; };
		virtual bool OnMouseButtonDown (Uint8 button, Uint16 xpos, Uint16 ypos) { return false; };

		/** \brief Draws the content of the Overlay */
		virtual void Draw () = 0;
};

typedef boost::shared_ptr<OverlayBase> OverlayBasePtr;

/** \brief Takes care of all OverlayBase classes and proxies input and drawing with regard to the current game state of ModelBase
 *
 * \note You need to set the ModelBase pointer manually by calling OverlayManager::SetModel()!
 */
class OverlayManager {
	public:
		/** \brief Calls OverlayBase::Init() for all registered Overlays */
		void InitOverlays();

		/** \brief Draws the Overlays associated with the current game state */
		void Draw();
		void Register (OverlayBasePtr overlay, unsigned int game_state);

		/* Input forwarding for the overlays */
		bool SendKeyDown (const SDL_keysym &keysym);
		bool SendKeyUp (const SDL_keysym &keysym);
		bool SendMouseButtonUp (Uint8 button, Uint16 xpos, Uint16 ypos);
		bool SendMouseButtonDown (Uint8 button, Uint16 xpos, Uint16 ypos);

	private:
		/** \brief Keeps the list of OverlayBase for each game state */
		std::map<unsigned int, std::list<OverlayBasePtr> > mOverlays;
};

};

#endif /* OVERLAYBASE */