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polled.H

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#ifndef _polled_H_
#define _polled_H_

#include "dev/dev.H"

// 
//  DEVpoll_obs - callback just before devices are polled
//    Register to be notified just before the devices are polled
//  each frame by using the global instance DEV_POLLobs().
//
class DEVpoll_obs {
   public: 
     class data {
     };
     virtual void  notify(const data &) = 0;
};

extern OBSlist<DEVpoll_obs> &DEV_POLLobs();

//
// This is a mixin class used for all devices that need to poll their inputs. 
// It exists (rather than having each polled device add itself to the 
// appropriate FD_MANAGER) so that all polled input devices can be polled at 
// a controlled time, right before drawing, to reduce lag. 
//
class DllImpExp DEVpolled {
 protected:
   static ARRAY<DEVpolled*> *_pollable;
   static ARRAY<DEVpolled *> &pollable() { if (!_pollable)
                                             _pollable = new ARRAY<DEVpolled*>;
                                          return *_pollable; }

   /* ---------- abstract polling interface -------------- */
   virtual void do_poll() = 0;   // Override with device-specific poll operation
   
 public:
   void        add_poll()        { pollable() += this; }
   void        rem_poll()        { pollable() -= this; }
   
   static void run_polls();
};


#endif

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