src/object_factory.hpp

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