src/object_factory.hpp

   1 //  $Id$
   2 //
   3 //  SuperTux
   4 //  Copyright (C) 2004 Ricardo Cruz <rick2@aeiou.pt>
   5 //  Copyright (C) 2006 Matthias Braun <matze@braunis.de>
   6 //
   7 //  This program is free software; you can redistribute it and/or
   8 //  modify it under the terms of the GNU General Public License
   9 //  as published by the Free Software Foundation; either version 2
  10 //  of the License, or (at your option) any later version.
  11 //
  12 //  This program is distributed in the hope that it will be useful,
  13 //  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 //  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 //  GNU General Public License for more details.
  16 //
  17 //  You should have received a copy of the GNU General Public License
  18 //  along with this program; if not, write to the Free Software
  19 //  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  20 #ifndef OBJECT_FACTORY_H
  21 #define OBJECT_FACTORY_H
  22
  23 #include <string>
  24 #include <map>
  25
  26 namespace lisp { class Lisp; }
  27 class Vector;
  28 class GameObject;
  29
  30 class Factory
  31 {
  32 public:
  33   virtual ~Factory()
  34   { }
  35
  36   /** Creates a new gameobject from a lisp node.
  37    * Remember to delete the objects later
  38    */
  39   virtual GameObject* create_object(const lisp::Lisp& reader) = 0;
  40
  41   typedef std::map<std::string, Factory*> Factories;
  42   static Factories &get_factories()
  43   {
  44     static Factories object_factories;
  45     return object_factories;
  46   }
  47 };
  48
  49 GameObject* create_object(const std::string& name, const lisp::Lisp& reader);
  50 GameObject* create_object(const std::string& name, const Vector& pos);
  51
  52 /** comment from Matze:
  53  * Yes I know macros are evil, but in this specific case they save
  54  * A LOT of typing and evil code duplication.
  55  * I'll happily accept alternatives if someone can present me one that does
  56  * not involve typing 4 or more lines for each object class
  57  */
  58 #define IMPLEMENT_FACTORY(CLASS, NAME)                            \
  59 class INTERN_##CLASS##Factory : public Factory                    \
  60 {                                                                 \
  61 public:                                                           \
  62   INTERN_##CLASS##Factory()                                       \
  63   {                                                               \
  64     get_factories()[NAME] = this;                                \
  65   }                                                               \
  66                                                                   \
  67   ~INTERN_##CLASS##Factory()                                      \
  68   {                                                               \
  69     get_factories().erase(NAME);                                 \
  70   }                                                               \
  71                                                                   \
  72   virtual GameObject* create_object(const lisp::Lisp& reader)     \
  73   {                                                               \
  74     return new CLASS(reader);                                     \
  75   }                                                               \
  76 };                                                                \
  77 static INTERN_##CLASS##Factory factory_##CLASS;
  78
  79 #endif