Steve's improvements to noise generators.
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martynshaw99
parent
2e8517f2ba
commit
cf972a390d
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@ -20,6 +20,8 @@
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#include "../ShuttleGui.h"
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#include "../WaveTrack.h"
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#include <math.h>
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#ifndef M_PI
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#define M_PI 3.14159265358979323846 /* pi */
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#endif
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@ -42,7 +44,7 @@ bool EffectNoise::PromptUser()
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noiseTypeList.Add(_("White"));
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noiseTypeList.Add(_("Pink"));
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noiseTypeList.Add(_("Brown"));
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noiseTypeList.Add(_("Brownian"));
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NoiseDialog dlog(this, mParent, _("Noise Generator"));
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@ -94,8 +96,7 @@ bool EffectNoise::TransferParameters( Shuttle & shuttle )
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bool EffectNoise::MakeNoise(float *buffer, sampleCount len, float fs, float amplitude)
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{
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float white, buf0, buf1, buf2, buf3, buf4, buf5;
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float a0, b1, fc, y;
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float white;
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sampleCount i;
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float div = ((float)RAND_MAX) / 2.0f;
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@ -107,37 +108,39 @@ bool EffectNoise::MakeNoise(float *buffer, sampleCount len, float fs, float ampl
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break;
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case 1: // pink
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white=buf0=buf1=buf2=buf3=buf4=buf5=0;
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// based on Paul Kellet's "instrumentation grade" algorithm.
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white=0;
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// 0.55f is an experimental normalization factor: thanks to Martyn
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amplitude *= 0.55f;
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for(i=0; i<len; i++) {
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white=(rand() / div) - 1.0f;
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buf0=0.997f * buf0 + 0.029591f * white;
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buf1=0.985f * buf1 + 0.032534f * white;
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buf2=0.950f * buf2 + 0.048056f * white;
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buf3=0.850f * buf3 + 0.090579f * white;
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buf4=0.620f * buf4 + 0.108990f * white;
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buf5=0.250f * buf5 + 0.255784f * white;
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buffer[i] = amplitude * (buf0 + buf1 + buf2 + buf3 + buf4 + buf5);
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};
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break;
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// 0.129f is an experimental normalization factor.
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amplitude *= 0.129f;
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for(i=0; i<len; i++) {
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white=(rand() / div) - 1.0f;
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buf0=0.99886f * buf0 + 0.0555179f * white;
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buf1=0.99332f * buf1 + 0.0750759f * white;
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buf2=0.96900f * buf2 + 0.1538520f * white;
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buf3=0.86650f * buf3 + 0.3104856f * white;
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buf4=0.55000f * buf4 + 0.5329522f * white;
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buf5=-0.7616f * buf5 - 0.0168980f * white;
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buffer[i] = amplitude *
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(buf0 + buf1 + buf2 + buf3 + buf4 + buf5 + buf6 + white * 0.5362);
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buf6 = white * 0.115926;
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}
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break;
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case 2: // brown
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// fc=100 Hz,
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// y[n]=a0*x[n] + b1*y[n-1];
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white=a0=b1=fc=y=0;
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fc=100; //fs=44100;
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b1=exp(-2*M_PI*fc/fs);
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a0=1.0f-b1;
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case 2: // Brownian
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white=0;
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//float leakage=0.997; // experimental value at 44.1kHz
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//double scaling = 0.05; // experimental value at 44.1kHz
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// min and max protect against instability at extreme sample rates.
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float leakage = ((fs-144.0)/fs < 0.9999)? (fs-144.0)/fs : 0.9999;
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float scaling = (9.0/sqrt(fs) > 0.01)? 9.0/sqrt(fs) : 0.01;
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// 6.2f is an experimental normalization factor: thanks to Martyn
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amplitude *= 6.2f;
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for(i=0; i<len; i++){
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white=(rand() / div) - 1.0f;
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y = (a0 * white + b1 * y);
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z = leakage * y + white * scaling;
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y = (fabs(z) > 1.0) ? (leakage * y - white * scaling) : z;
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buffer[i] = amplitude * y;
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};
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}
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break;
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}
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return true;
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@ -193,10 +196,7 @@ void NoiseDialog::PopulateOrExchange( ShuttleGui & S )
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{
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S.StartMultiColumn(2, wxCENTER);
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{
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// The added colon to improve visual consistency was placed outside
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// the translatable strings to avoid breaking translations close to 2.0.
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// TODO: Make colon part of the translatable string after 2.0.
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S.TieChoice(_("Noise type") + wxString(wxT(":")), nType, nTypeList);
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S.TieChoice(_("Noise type:"), nType, nTypeList);
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S.TieNumericTextBox(_("Amplitude (0-1)") + wxString(wxT(":")), nAmplitude, 10);
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S.AddPrompt(_("Duration") + wxString(wxT(":")));
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if (mNoiseDurationT == NULL)
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@ -248,5 +248,3 @@ bool NoiseDialog::TransferDataFromWindow()
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void NoiseDialog::OnTimeCtrlUpdate(wxCommandEvent & event) {
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Fit();
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}
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@ -36,6 +36,7 @@ class EffectNoise : public BlockGenerator {
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SetEffectFlags(BUILTIN_EFFECT | INSERT_EFFECT);
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noiseType = 0;
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noiseAmplitude = 1.0;
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y = z = buf0 = buf1 = buf2 = buf3 = buf4 = buf5 = buf6 = 0;
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}
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virtual bool Init();
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@ -71,9 +72,11 @@ class EffectNoise : public BlockGenerator {
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sampleCount numSamples;
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int noiseType;
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double noiseAmplitude;
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float y, z, buf0, buf1, buf2, buf3, buf4, buf5, buf6;
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protected:
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virtual bool MakeNoise(float *buffer, sampleCount len, float fs, float amplitude);
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//double mCurRate;
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// friendship ...
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friend class NoiseDialog;
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@ -115,16 +118,3 @@ class NoiseDialog:public EffectDialog {
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};
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#endif
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// Indentation settings for Vim and Emacs and unique identifier for Arch, a
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// version control system. Please do not modify past this point.
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//
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// Local Variables:
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// c-basic-offset: 3
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// indent-tabs-mode: nil
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// End:
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//
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// vim: et sts=3 sw=3
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// arch-tag: 3d52765e-51bb-4f53-8ed8-4239f7b42d16
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