lang/LangSource/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 "Samp.h"
  23 #include "SC_Constants.h"
  24 #include <stdlib.h>
  25 #include <stdexcept>
  26
  27 float32 gSine[kSineSize+1];
  28 float32 gPMSine[kSineSize+1];
  29 float32 gInvSine[kSineSize+1];
  30 float32 gSineWavetable[2*kSineSize];
  31
  32 void SignalAsWavetable(float32* signal, float32* wavetable, long inSize)
  33 {
  34         float32 val1, val2;
  35
  36         float32* in = signal;
  37         float32* out = wavetable - 1;
  38         for (int i=0; i<inSize - 1; ++i) {
  39                 val1 = in[i];
  40                 val2 = in[i+1];
  41                 *++out = 2.f * val1 - val2;
  42                 *++out = val2 - val1;
  43         }
  44         val1 = in[inSize-1];
  45         val2 = in[0];
  46         *++out = 2.f * val1 - val2;
  47         *++out = val2 - val1;
  48 }
  49
  50 void WavetableAsSignal(float32* wavetable, float32* signal, long inSize)
  51 {
  52         float32* in = wavetable - 1;
  53         float32* out = signal - 1;
  54         for (int i=0; i<inSize; ++i) {
  55                 float32 a = *++in;
  56                 float32 b = *++in;
  57                 *++out = a + b;
  58         }
  59 }
  60
  61
  62 class SynthLibInit
  63 {
  64 public:
  65         SynthLibInit();
  66
  67         void FillTables();
  68 };
  69
  70 SynthLibInit gSynthLibInit;
  71
  72 SynthLibInit::SynthLibInit()
  73 {
  74         FillTables();
  75 }
  76
  77 void SynthLibInit::FillTables()
  78 {
  79         double sineIndexToPhase = twopi / kSineSize;
  80         double pmf = (1L << 29) / twopi;
  81         for (int i=0; i <= kSineSize; ++i) {
  82                 double phase = i * sineIndexToPhase;
  83                 float32 d = sin(phase);
  84                 gSine[i] = d;
  85                 gInvSine[i] = 1. / d;
  86                 gPMSine[i] = d * pmf;
  87         }
  88         SignalAsWavetable(gSine, gSineWavetable, kSineSize);
  89
  90         gInvSine[0] = gInvSine[kSineSize/2] = gInvSine[kSineSize] = kBadValue;
  91         int sz = kSineSize;
  92         int sz2 = sz>>1;
  93         for (int  i=1; i<=8; ++i) {
  94                 gInvSine[i] = gInvSine[sz-i] = kBadValue;
  95                 gInvSine[sz2-i] = gInvSine[sz2+i] = kBadValue;
  96         }
  97         //SignalAsWavetable(gInvSine, gInvSineWavetable, kSineSize);
  98 }
  99
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