nel/src/3d/mrm_level_detail.cpp

   1 // NeL - MMORPG Framework <http://dev.ryzom.com/projects/nel/>
   2 // Copyright (C) 2010  Winch Gate Property Limited
   3 //
   4 // This program is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU Affero General Public License as
   6 // published by the Free Software Foundation, either version 3 of the
   7 // License, or (at your option) any later version.
   8 //
   9 // This program is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU Affero General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU Affero General Public License
  15 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17
  18 #include "std3d.h"
  19
  20 #include "nel/3d/mrm_level_detail.h"
  21
  22 #ifdef DEBUG_NEW
  23 #define new DEBUG_NEW
  24 #endif
  25
  26 namespace NL3D
  27 {
  28
  29
  30 // ***************************************************************************
  31 void                    CMRMLevelDetail::compileDistanceSetup()
  32 {
  33         // Compute _OODistDelta.
  34         OODistanceDelta= 1.0f / (DistanceCoarsest - DistanceFinest);
  35         /* Compute exponent pow, such that 0.5= dMiddle^pow;
  36                 ie 0.5= e(ln dMiddle * pow)
  37         */
  38         float   dMiddle= (DistanceCoarsest - DistanceMiddle) * OODistanceDelta;
  39         DistancePow= (float)(log(0.5) / log(dMiddle));
  40 }
  41
  42
  43 // ***************************************************************************
  44 float                   CMRMLevelDetail::getLevelDetailFromDist(float dist)
  45 {
  46         if(dist <= DistanceFinest)
  47                 return 1;
  48         if(dist >= DistanceCoarsest)
  49                 return 0;
  50
  51         float   d= (DistanceCoarsest - dist) * OODistanceDelta;
  52         return  (float)pow(d, DistancePow);
  53 }
  54
  55
  56 } // NL3D