math.hxx

   1 //  $Id: math.hxx,v 1.5 2003/07/24 21:43:35 grumbel Exp $
   2 //
   3 //  Construo - A wire-frame construction gamee
   4 //  Copyright (C) 2000 Ingo Ruhnke <grumbel@gmx.de>
   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
  20 #ifndef CONSTRUO_MATH_HXX
  21 #define CONSTRUO_MATH_HXX
  22
  23 /** A collection of small math helper functions, some of them might be
  24     equal in functionality to standard STL functions, but provided
  25     here for portability and broken STL implementations
  26
  27     @brief A collection of mathematical helper functions */
  28 namespace Math {
  29
  30 const double pi   = 3.14159265358979323846;     /* pi */
  31 const double pi_2 = 1.57079632679489661923;     /* pi/2 */
  32
  33 template<class T>
  34 T min (const T& a, const T& b)
  35 {
  36   if (a < b)
  37     return a;
  38   else
  39     return b;
  40 }
  41
  42 template<class T>
  43 T max (const T& a, const T& b)
  44 {
  45   if (a > b)
  46     return a;
  47   else
  48     return b;
  49 }
  50
  51 template<class T>
  52 T mid (const T& a, const T& b, const T& c)
  53 {
  54   return max((a), min((b), (c)));
  55 }
  56
  57 inline int round(float a)
  58 {
  59   return int((a > 0) ? (a + .5f) : (a - .5));
  60 }
  61
  62 /** Round x to a multilple of n */
  63 inline int round_to(float x, int n)
  64 {
  65   if (x > 0)
  66     return static_cast<int>(x + (n/2)) / n * n;
  67   else
  68     return static_cast<int>(x - (n/2)) / n * n;
  69 }
  70
  71 } // namespace Math
  72
  73 #endif