nel/src/sound/driver/source.cpp

   1 // NeL - MMORPG Framework <http://dev.ryzom.com/projects/nel/>
   2 // Copyright (C) 2010  Winch Gate Property Limited
   3 //
   4 // This source file has been modified by the following contributors:
   5 // Copyright (C) 2012  Jan BOON (Kaetemi) <jan.boon@kaetemi.be>
   6 //
   7 // This program is free software: you can redistribute it and/or modify
   8 // it under the terms of the GNU Affero General Public License as
   9 // published by the Free Software Foundation, either version 3 of the
  10 // 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 Affero General Public License for more details.
  16 //
  17 // You should have received a copy of the GNU Affero General Public License
  18 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19
  20 #include "stdsound_lowlevel.h"
  21
  22 #include "nel/sound/driver/source.h"
  23
  24 using namespace NLMISC;
  25
  26 namespace NLSOUND
  27 {
  28
  29 // common method used only with OptionManualRolloff. return the volume in 1/100th DB ( = mB) modified
  30 sint32 ISource::computeManualRollOff(sint32 volumeMB, sint32 mbMin, sint32 mbMax, double alpha, float sqrdist, float distMin, float distMax)
  31 {
  32         if (sqrdist < distMin * distMin)
  33         {
  34                 // no attenuation
  35                 return volumeMB;
  36         }
  37         else if (sqrdist > distMax * distMax)
  38         {
  39                 // full attenuation
  40                 return mbMin;
  41         }
  42         else
  43         {
  44                 double dist = (double) sqrt(sqrdist);
  45
  46                 // linearly descending volume on a dB scale
  47                 double db1 = mbMin * (dist - distMin) / (distMax - distMin);
  48
  49                 if (alpha == 0.0) {
  50                         volumeMB += (sint32) db1;
  51
  52                 } else if (alpha > 0.0) {
  53                         double amp2 = 0.0001 + 0.9999 * (distMax - dist) / (distMax - distMin); // linear amp between 0.00001 and 1.0
  54                         double db2 = 2000.0 * log10(amp2); // convert to 1/100th decibels
  55                         volumeMB += (sint32) ((1.0 - alpha) * db1 + alpha * db2);
  56
  57                 } else if (alpha < 0.0) {
  58                         double amp3 = distMin / dist; // linear amplitude is 1/distance
  59                         double db3 = 2000.0 * log10(amp3); // convert to 1/100th decibels
  60                         volumeMB += (sint32) ((1.0 + alpha) * db1 - alpha * db3);
  61                 }
  62
  63                 clamp(volumeMB, mbMin, mbMax);
  64                 return volumeMB;
  65         }
  66 }
  67
  68 // common method used only with OptionManualRolloff. return the rolloff in amplitude ratio (gain)
  69 float ISource::computeManualRolloff(double alpha, float sqrdist, float distMin, float distMax)
  70 {
  71         /*static const sint mbMin = -10000;
  72         static const sint mbMax = 0;
  73         sint32 rolloffMb = ISource::computeManualRollOff(mbMax, mbMin, mbMax, alpha, sqrdist, distMin, distMax);
  74         float rolloffGain = (float)pow(10.0, (double)rolloffMb / 2000.0);
  75         clamp(rolloffGain, 0.0f, 1.0f);
  76         return rolloffGain;*/
  77
  78         static const double mbMin = -10000;
  79         static const double mbMax = 0;
  80
  81         if (sqrdist < distMin * distMin)
  82         {
  83                 // no attenuation
  84                 return 1.0f;
  85         }
  86         else
  87         {
  88                 if (alpha < 0.0f)
  89                 {
  90                         double dist = (double)sqrt(sqrdist);
  91                         // inverse distance rolloff
  92                         float rolloff = distMin / dist;
  93                         if (alpha <= -1.0f) return rolloff;
  94
  95                         if (dist > distMax)
  96                         {
  97                                 // full attenuation of mbrolloff
  98                                 return (-alpha * rolloff);
  99                         }
 100                         else
 101                         {
 102                                 double mb = mbMin * (dist - distMin) / (distMax - distMin);
 103                                 float mbrolloff = (float)pow(10.0, (double)mb / 2000.0);
 104                                 return ((1.0 + alpha) * mbrolloff - alpha * rolloff);
 105                         }
 106                 }
 107                 else
 108                 {
 109                         if (sqrdist > distMax * distMax)
 110                         {
 111                                 // full attenuation
 112                                 return 0.0f;
 113                         }
 114                         double dist = (double)sqrt(sqrdist);
 115                         if (alpha == 0.0f)
 116                         {
 117                                 // linearly descending volume on a dB scale
 118                                 double mb = mbMin * (dist - distMin) / (distMax - distMin);
 119                                 return (float)pow(10.0, (double)mb / 2000.0);
 120                         }
 121                         else // if (alpha > 0.0f)
 122                         {
 123                                 // linear distance rolloff
 124                                 float rolloff = (distMax - dist) / (distMax - distMin);
 125                                 if (alpha >= 1.0f) return rolloff;
 126
 127                                 double mb = mbMin * (dist - distMin) / (distMax - distMin);
 128                                 float mbrolloff = (float)pow(10.0, (double)mb / 2000.0);
 129                                 return ((1.0 - alpha) * mbrolloff + alpha * rolloff);
 130                         }
 131                 }
 132         }
 133 }
 134
 135 } // NLSOUND
 136
 137 /* end of file */