airwindows/plugins/MacAU/Exciter/Exciter.cpp
2022-11-21 09:20:21 -05:00

241 lines
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C++
Executable file

/*
* File: Exciter.cpp
*
* Version: 1.0
*
* Created: 9/6/22
*
* Copyright: Copyright © 2022 Airwindows, Airwindows uses the MIT license
*
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* software.
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*/
/*=============================================================================
Exciter.cpp
=============================================================================*/
#include "Exciter.h"
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
COMPONENT_ENTRY(Exciter)
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Exciter::Exciter
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Exciter::Exciter(AudioUnit component)
: AUEffectBase(component)
{
CreateElements();
Globals()->UseIndexedParameters(kNumberOfParameters);
SetParameter(kParam_One, kDefaultValue_ParamOne );
SetParameter(kParam_Two, kDefaultValue_ParamTwo );
#if AU_DEBUG_DISPATCHER
mDebugDispatcher = new AUDebugDispatcher (this);
#endif
}
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Exciter::GetParameterValueStrings
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ComponentResult Exciter::GetParameterValueStrings(AudioUnitScope inScope,
AudioUnitParameterID inParameterID,
CFArrayRef * outStrings)
{
return kAudioUnitErr_InvalidProperty;
}
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Exciter::GetParameterInfo
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ComponentResult Exciter::GetParameterInfo(AudioUnitScope inScope,
AudioUnitParameterID inParameterID,
AudioUnitParameterInfo &outParameterInfo )
{
ComponentResult result = noErr;
outParameterInfo.flags = kAudioUnitParameterFlag_IsWritable
| kAudioUnitParameterFlag_IsReadable;
if (inScope == kAudioUnitScope_Global) {
switch(inParameterID)
{
case kParam_One:
AUBase::FillInParameterName (outParameterInfo, kParameterOneName, false);
outParameterInfo.unit = kAudioUnitParameterUnit_Generic;
outParameterInfo.minValue = 0.0;
outParameterInfo.maxValue = 1.0;
outParameterInfo.defaultValue = kDefaultValue_ParamOne;
break;
case kParam_Two:
AUBase::FillInParameterName (outParameterInfo, kParameterTwoName, false);
outParameterInfo.unit = kAudioUnitParameterUnit_Generic;
outParameterInfo.minValue = 0.0;
outParameterInfo.maxValue = 1.0;
outParameterInfo.defaultValue = kDefaultValue_ParamTwo;
break;
default:
result = kAudioUnitErr_InvalidParameter;
break;
}
} else {
result = kAudioUnitErr_InvalidParameter;
}
return result;
}
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Exciter::GetPropertyInfo
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ComponentResult Exciter::GetPropertyInfo (AudioUnitPropertyID inID,
AudioUnitScope inScope,
AudioUnitElement inElement,
UInt32 & outDataSize,
Boolean & outWritable)
{
return AUEffectBase::GetPropertyInfo (inID, inScope, inElement, outDataSize, outWritable);
}
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Exciter::GetProperty
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ComponentResult Exciter::GetProperty( AudioUnitPropertyID inID,
AudioUnitScope inScope,
AudioUnitElement inElement,
void * outData )
{
return AUEffectBase::GetProperty (inID, inScope, inElement, outData);
}
// Exciter::Initialize
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ComponentResult Exciter::Initialize()
{
ComponentResult result = AUEffectBase::Initialize();
if (result == noErr)
Reset(kAudioUnitScope_Global, 0);
return result;
}
#pragma mark ____ExciterEffectKernel
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Exciter::ExciterKernel::Reset()
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
void Exciter::ExciterKernel::Reset()
{
for (int x = 0; x < 11; x++) {biquad[x] = 0.0;}
fpd = 1.0; while (fpd < 16386) fpd = rand()*UINT32_MAX;
}
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Exciter::ExciterKernel::Process
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
void Exciter::ExciterKernel::Process( const Float32 *inSourceP,
Float32 *inDestP,
UInt32 inFramesToProcess,
UInt32 inNumChannels,
bool &ioSilence )
{
UInt32 nSampleFrames = inFramesToProcess;
const Float32 *sourceP = inSourceP;
Float32 *destP = inDestP;
biquad[0] = ((GetParameter( kParam_One )*7000.0)+8000.0)/GetSampleRate();
biquad[1] = GetParameter( kParam_One )+GetParameter( kParam_Two )+0.7071;
//tighter resonance as frequency and boost increases
double boost = pow(GetParameter( kParam_Two ),2.0)*16.0;
double K = tan(M_PI * biquad[0]);
double norm = 1.0 / (1.0 + K / biquad[1] + K * K);
biquad[2] = K / 0.7071 * norm;
biquad[4] = -biquad[2];
biquad[5] = 2.0 * (K * K - 1.0) * norm;
biquad[6] = (1.0 - K / biquad[1] + K * K) * norm;
//bandpass to focus the intensity of the effect
while (nSampleFrames-- > 0) {
double inputSample = *sourceP;
if (fabs(inputSample)<1.18e-23) inputSample = fpd * 1.18e-17;
double outSample = biquad[2]*inputSample+biquad[4]*biquad[8]-biquad[5]*biquad[9]-biquad[6]*biquad[10];
biquad[8] = biquad[7]; biquad[7] = inputSample; biquad[10] = biquad[9];
biquad[9] = outSample; //DF1
//so the audio we're working with is going to be a bandpassed signal: only high mids
outSample *= boost;
if (outSample > M_PI) outSample = M_PI;
if (outSample < -M_PI) outSample = -M_PI;
outSample -= sin(outSample);
//so we're clipping to generate artifacts, but subtracting them, meaning that
//our deviations from the unclipped waveform are now negative in form.
outSample *= boost;
if (outSample > M_PI) outSample = M_PI;
if (outSample < -M_PI) outSample = -M_PI;
outSample = sin(outSample);
//now we're clipping the result, to make the peaks less intense
inputSample -= outSample;
//and we apply only those deviations from distorted high mids, by subtracting them from
//the original full bandwidth audio. And that's how analog aural exciters basically work.
//The real ones used a 4049 chip sometimes to produce the soft saturation we're getting with sin()
if (inputSample > 1.0) inputSample = 1.0;
if (inputSample < -1.0) inputSample = -1.0;
//and we'll do the harshest of hardclips to cope with how intense the new peaks can get,
//without in any way dialing back the ruthless brightness the exciter can create.
//begin 32 bit floating point dither
int expon; frexpf((float)inputSample, &expon);
fpd ^= fpd << 13; fpd ^= fpd >> 17; fpd ^= fpd << 5;
inputSample += ((double(fpd)-uint32_t(0x7fffffff)) * 5.5e-36l * pow(2,expon+62));
//end 32 bit floating point dither
*destP = inputSample;
sourceP += inNumChannels; destP += inNumChannels;
}
}