src/Spring.h

   1 /*
   2  * Spring.h
   3  * Daniel Nelson - 8/24/0
   4  *
   5  * Copyright (C) 2000  Daniel Nelson
   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  *
  21  * Daniel Nelson - aluminumangel.org
  22  * 174 W. 18th Ave.
  23  * Columbus, OH  43210
  24  */
  25
  26 #ifndef SPRING_H
  27 #define SPRING_H
  28
  29
  30 // spring constants, if you will
  31 #define SP_IMPACT_VELOCITY                      (0.1f)
  32 #define SP_GARBAGE_DENSITY                      (0.2f)
  33 #define SP_STIFFNESS                            (0.1f)
  34 #define SP_DRAG                                 (0.1f)
  35
  36 /* static */ class Spring {
  37 public:
  38   static void gameStart (   );
  39
  40   static inline void notifyImpact ( int height, int width )
  41   {
  42     float dv = (SP_IMPACT_VELOCITY + v) * (height * width) * SP_GARBAGE_DENSITY;
  43     if (dv > 0.0f)
  44       v -= dv;
  45   };
  46
  47   static inline void timeStep (   )
  48   {
  49     y += v;
  50     v -= SP_STIFFNESS * y + SP_DRAG * v;
  51   };
  52
  53   static float y;
  54
  55 private:
  56   static float v;
  57 };
  58
  59 #endif