server/scsynth/Samp.cpp

   1 /*
   2         SuperCollider real time audio synthesis system
   3     Copyright (c) 2002 James McCartney. All rights reserved.
   4         http://www.audiosynth.com
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
  19 */
  20
  21
  22 #include "SC_Samp.h"
  23 #include "SC_Constants.h"
  24 #include <stdlib.h>
  25
  26 float32 gSine[kSineSize+1];
  27 float32 gInvSine[kSineSize+1];
  28 float32 gSineWavetable[2*kSineSize];
  29
  30 void SignalAsWavetable(float32* signal, float32* wavetable, long inSize)
  31 {
  32         float32 val1, val2;
  33
  34         float32* in = signal;
  35         float32* out = wavetable - 1;
  36         for (int i=0; i<inSize; ++i) {
  37                 val1 = in[i];
  38                 val2 = in[i+1];
  39                 *++out = 2.f * val1 - val2;
  40                 *++out = val2 - val1;
  41         }
  42         val1 = in[inSize-1];
  43         val2 = in[0];
  44         *++out = 2.f * val1 - val2;
  45         *++out = val2 - val1;
  46 }
  47
  48 class AudioLibInit
  49 {
  50 public:
  51         AudioLibInit();
  52
  53         void FillTables();
  54 };
  55
  56 AudioLibInit gAudioLibInit;
  57
  58 AudioLibInit::AudioLibInit()
  59 {
  60         FillTables();
  61 }
  62
  63 void AudioLibInit::FillTables()
  64 {
  65         double sineIndexToPhase = twopi / kSineSize;
  66         for (int i=0; i <= kSineSize; ++i) {
  67                 double phase = i * sineIndexToPhase;
  68                 float32 d = (float)sin(phase);
  69                 gSine[i] = d;
  70         if( d == 0. )
  71             gInvSine[i] = 0.;
  72         else
  73             gInvSine[i] = (float)(1. / d);
  74         }
  75         SignalAsWavetable(gSine, gSineWavetable, kSineSize);
  76
  77         gInvSine[0] = gInvSine[kSineSize/2] = gInvSine[kSineSize] = kBadValue;
  78         int sz = kSineSize;
  79         int sz2 = sz>>1;
  80         for (int  i=1; i<=32; ++i) {
  81                 gInvSine[i] = gInvSine[sz-i] = kBadValue;
  82                 gInvSine[sz2-i] = gInvSine[sz2+i] = kBadValue;
  83         }
  84         //SignalAsWavetable(gInvSine, gInvSineWavetable, kSineSize);
  85 }
  86
  87
  88