sdl_cevent.cpp

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#include "cevent.h"

#include <SDL.h>

namespace SDLDriver {

class CEventSDL : public CEvent {
private:
  /* The wrapped event structure. */
  SDL_Event *event;

public:
  CEventSDL(SDL_Event *e) { event = e; }
  virtual ~CEventSDL() { delete event; }
  int is_ctrl_pressed() {
    return event->key.keysym.mod & KMOD_CTRL;
  }
  char get_key_ascii_value() {
    return event->key.keysym.sym;
  }
  int get_type() {
    switch (event->type) {
      case SDL_KEYDOWN:
        return CEvent::TYPE_KEY_DOWN;
      case SDL_QUIT:
        return CEvent::TYPE_APPLICATION_EXIT;
    }
    return 0;
  }
};

class CEventSystemSDL : public CEventSystem {
private:
  /* This is an SDL_EventFilter function that filters out all events except the ones
    that we're interested in.  SDL calls this function, and its documentation is at
    http://sdldoc.csn.ul.ie/sdlseteventfilter.php . */
  static int sdl_event_filter(const SDL_Event *event) {
    switch (event->type) {
      case SDL_KEYDOWN:
      case SDL_QUIT:
        /* Yes, we want these kinds of events, so return true. */
        return 1;
      default:
        /* We don't want any other kinds of events, so return false. */
        return 0;
    }
  }

  CEventSystemSDL() {
    /* Set our event filter so we only receive the events we want. */
    SDL_SetEventFilter(sdl_event_filter);    
  }

public:
  friend class CEventSystemFactorySDL;

  virtual CEvent *get_next_event() {
    if (SDL_PollEvent(NULL)) {
      SDL_Event *e = new SDL_Event;
      SDL_PollEvent(e);
      return new CEventSDL(e);
    }
    return 0;
  }
};

class CEventSystemFactorySDL : public CEventSystemFactory {
  virtual CEventSystem *make_singleton() {
    return new CEventSystemSDL();
  }
};

  /* Add the factory retriever to the SDLDriver namespace's repertoire. */
  CEventSystemFactory *make_event_system_factory() {
    return new CEventSystemFactorySDL();
  }
}

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