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