winamp/Src/external_dependencies/openmpt-trunk/soundlib/plugins/dmo/Distortion.cpp

217 lines
5.3 KiB
C++
Raw Normal View History

2024-09-24 08:54:57 -04:00
/*
* Distortion.cpp
* --------------
* Purpose: Implementation of the DMO Distortion DSP (for non-Windows platforms)
* Notes : The original plugin's integer and floating point code paths only
* behave identically when feeding floating point numbers in range
* [-32768, +32768] rather than the usual [-1, +1] into the plugin.
* Authors: OpenMPT Devs
* The OpenMPT source code is released under the BSD license. Read LICENSE for more details.
*/
#include "stdafx.h"
#ifndef NO_PLUGINS
#include "../../Sndfile.h"
#include "Distortion.h"
#include "DMOUtils.h"
#include "mpt/base/numbers.hpp"
#endif // !NO_PLUGINS
OPENMPT_NAMESPACE_BEGIN
#ifndef NO_PLUGINS
namespace DMO
{
IMixPlugin* Distortion::Create(VSTPluginLib &factory, CSoundFile &sndFile, SNDMIXPLUGIN *mixStruct)
{
return new (std::nothrow) Distortion(factory, sndFile, mixStruct);
}
Distortion::Distortion(VSTPluginLib &factory, CSoundFile &sndFile, SNDMIXPLUGIN *mixStruct)
: IMixPlugin(factory, sndFile, mixStruct)
{
m_param[kDistGain] = 0.7f;
m_param[kDistEdge] = 0.15f;
m_param[kDistPreLowpassCutoff] = 1.0f;
m_param[kDistPostEQCenterFrequency] = 0.291f;
m_param[kDistPostEQBandwidth] = 0.291f;
m_mixBuffer.Initialize(2, 2);
InsertIntoFactoryList();
}
void Distortion::Process(float *pOutL, float *pOutR, uint32 numFrames)
{
if(!m_mixBuffer.Ok())
return;
const float *in[2] = { m_mixBuffer.GetInputBuffer(0), m_mixBuffer.GetInputBuffer(1) };
float *out[2] = { m_mixBuffer.GetOutputBuffer(0), m_mixBuffer.GetOutputBuffer(1) };
for(uint32 i = numFrames; i != 0; i--)
{
for(uint8 channel = 0; channel < 2; channel++)
{
float x = *(in[channel])++;
// Pre EQ
float z = x * m_preEQa0 + m_preEQz1[channel] * m_preEQb1;
m_preEQz1[channel] = z;
z *= 1073741824.0f; // 32768^2
// The actual distortion
z = logGain(z, m_edge, m_shift);
// Post EQ / Gain
z = (z * m_postEQa0) - m_postEQz1[channel] * m_postEQb1 - m_postEQz2[channel] * m_postEQb0;
m_postEQz1[channel] = z * m_postEQb0 + m_postEQz2[channel];
m_postEQz2[channel] = z;
z *= (1.0f / 1073741824.0f); // 32768^2
*(out[channel])++ = z;
}
}
ProcessMixOps(pOutL, pOutR, m_mixBuffer.GetOutputBuffer(0), m_mixBuffer.GetOutputBuffer(1), numFrames);
}
PlugParamValue Distortion::GetParameter(PlugParamIndex index)
{
if(index < kDistNumParameters)
{
return m_param[index];
}
return 0;
}
void Distortion::SetParameter(PlugParamIndex index, PlugParamValue value)
{
if(index < kDistNumParameters)
{
value = mpt::safe_clamp(value, 0.0f, 1.0f);
m_param[index] = value;
RecalculateDistortionParams();
}
}
void Distortion::Resume()
{
m_isResumed = true;
RecalculateDistortionParams();
PositionChanged();
}
void Distortion::PositionChanged()
{
// Reset filter state
m_preEQz1[0] = m_preEQz1[1] = 0;
m_postEQz1[0] = m_postEQz2[0] = 0;
m_postEQz1[1] = m_postEQz2[1] = 0;
}
#ifdef MODPLUG_TRACKER
CString Distortion::GetParamName(PlugParamIndex param)
{
switch(param)
{
case kDistGain: return _T("Gain");
case kDistEdge: return _T("Edge");
case kDistPreLowpassCutoff: return _T("PreLowpassCutoff");
case kDistPostEQCenterFrequency: return _T("PostEQCenterFrequency");
case kDistPostEQBandwidth: return _T("PostEQBandwidth");
}
return CString();
}
CString Distortion::GetParamLabel(PlugParamIndex param)
{
switch(param)
{
case kDistGain:
return _T("dB");
case kDistPreLowpassCutoff:
case kDistPostEQCenterFrequency:
case kDistPostEQBandwidth:
return _T("Hz");
}
return CString();
}
CString Distortion::GetParamDisplay(PlugParamIndex param)
{
float value = m_param[param];
switch(param)
{
case kDistGain:
value = GainInDecibel();
break;
case kDistEdge:
value *= 100.0f;
break;
case kDistPreLowpassCutoff:
case kDistPostEQCenterFrequency:
case kDistPostEQBandwidth:
value = FreqInHertz(value);
break;
}
CString s;
s.Format(_T("%.2f"), value);
return s;
}
#endif // MODPLUG_TRACKER
void Distortion::RecalculateDistortionParams()
{
// Pre-EQ
m_preEQb1 = std::sqrt((2.0f * std::cos(2.0f * mpt::numbers::pi_v<float> * std::min(FreqInHertz(m_param[kDistPreLowpassCutoff]) / m_SndFile.GetSampleRate(), 0.5f)) + 3.0f) / 5.0f);
m_preEQa0 = std::sqrt(1.0f - m_preEQb1 * m_preEQb1);
// Distortion
float edge = 2.0f + m_param[kDistEdge] * 29.0f;
m_edge = static_cast<uint8>(edge); // 2...31 shifted bits
m_shift = mpt::bit_width(m_edge);
static constexpr float LogNorm[32] =
{
1.00f, 1.00f, 1.50f, 1.00f, 1.75f, 1.40f, 1.17f, 1.00f,
1.88f, 1.76f, 1.50f, 1.36f, 1.25f, 1.15f, 1.07f, 1.00f,
1.94f, 1.82f, 1.72f, 1.63f, 1.55f, 1.48f, 1.41f, 1.35f,
1.29f, 1.24f, 1.19f, 1.15f, 1.11f, 1.07f, 1.03f, 1.00f,
};
// Post-EQ
const float gain = std::pow(10.0f, GainInDecibel() / 20.0f);
const float postFreq = 2.0f * mpt::numbers::pi_v<float> * std::min(FreqInHertz(m_param[kDistPostEQCenterFrequency]) / m_SndFile.GetSampleRate(), 0.5f);
const float postBw = 2.0f * mpt::numbers::pi_v<float> * std::min(FreqInHertz(m_param[kDistPostEQBandwidth]) / m_SndFile.GetSampleRate(), 0.5f);
const float t = std::tan(5.0e-1f * postBw);
m_postEQb1 = ((1.0f - t) / (1.0f + t));
m_postEQb0 = -std::cos(postFreq);
m_postEQa0 = gain * std::sqrt(1.0f - m_postEQb0 * m_postEQb0) * std::sqrt(1.0f - m_postEQb1 * m_postEQb1) * LogNorm[m_edge];
}
} // namespace DMO
#else
MPT_MSVC_WORKAROUND_LNK4221(Distortion)
#endif // !NO_PLUGINS
OPENMPT_NAMESPACE_END