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floatrand.h

00001 /*
00002     Copyright (C) 2004 by Jorrit Tyberghein
00003     Copyright (C) 2005 by Eric Sunshine
00004 
00005     This library is free software; you can redistribute it and/or
00006     modify it under the terms of the GNU Library General Public
00007     License as published by the Free Software Foundation; either
00008     version 2 of the License, or (at your option) any later version.
00009 
00010     This library is distributed in the hope that it will be useful,
00011     but WITHOUT ANY WARRANTY; without even the implied warranty of
00012     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013     Library General Public License for more details.
00014 
00015     You should have received a copy of the GNU Library General Public
00016     License along with this library; if not, write to the Free
00017     Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
00018 */
00019 
00020 #ifndef __CS_CSUTIL_FLOATRAND_H__
00021 #define __CS_CSUTIL_FLOATRAND_H__
00022 
00023 #include "csextern.h"
00024 
00028 class CS_CSUTIL_EXPORT csRandomFloatGen
00029 {
00030 private:
00031   unsigned int seed;
00032 
00033 public:
00035   csRandomFloatGen ()
00036   { Initialize(); }
00038   csRandomFloatGen (unsigned int seed)
00039   { Initialize(seed); }
00040 
00042   void Initialize();
00044   void Initialize(unsigned int new_seed)
00045   { seed = new_seed; }
00046 
00048   float Get()
00049   {
00050     unsigned int const b = 1664525;
00051     unsigned int const c = 1013904223;
00052     seed = b * seed + c;
00053     uint32 temp = 0x3f800000 | (0x007fffff & seed);
00054     return (*(float*)&temp) - 1.0;
00055   }
00056 
00058   float Get(float max)
00059   {
00060     return max * Get();
00061   }
00062 
00064   float Get(float min, float max)
00065   {
00066     float const w = max - min;
00067     return min + w * Get();
00068   }
00069 
00071   float GetAngle()
00072   {
00073     return TWO_PI * Get();
00074   }
00075 };
00076 
00077 #endif // __CS_CSUTIL_FLOATRAND_H__

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