src/supertux/object_factory.hpp

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