Merged revision(s) 20302 from trunk/OpenMPT:

[Fix] Chorus/Flanger: Avoid occasional popping once the mix rate exceeds ~136.5 kHz (https://bugs.openmpt.org/view.php?id=1752).
[Mod] Chorus/Flanger: Rename Triangle waveshape to Square, because that's what those convoluted computations really end up doing in the end.
........


git-svn-id: https://source.openmpt.org/svn/openmpt/branches/OpenMPT-1.30@20304 56274372-70c3-4bfc-bfc3-4c3a0b034d27

soundlib/plugins/dmo/Chorus.cpp

@@ -11,8 +11,8 @@
 #include "stdafx.h"
 
 #ifndef NO_PLUGINS
-#include "../../Sndfile.h"
 #include "Chorus.h"
+#include "../../Sndfile.h"
 #include "mpt/base/numbers.hpp"
 #endif // !NO_PLUGINS
 
@@ -52,7 +52,7 @@ int32 Chorus::GetBufferIntOffset(int32 fpOffset) const
  if(fpOffset < 0)
  fpOffset += m_bufSize * 4096;
  MPT_ASSERT(fpOffset >= 0);
- return (fpOffset / 4096) % m_bufSize;
+ return (m_bufPos + (fpOffset / 4096)) % m_bufSize;
 }
 
 
@@ -64,7 +64,7 @@ void Chorus::Process(float *pOutL, float *pOutR, uint32 numFrames)
  const float *in[2] = { m_mixBuffer.GetInputBuffer(0), m_mixBuffer.GetInputBuffer(1) };
  float *out[2] = { m_mixBuffer.GetOutputBuffer(0), m_mixBuffer.GetOutputBuffer(1) };
 
- const bool isTriangle = IsTriangle();
+ const bool isSquare = IsSquare();
  const float feedback = Feedback() / 100.0f;
  const float wetDryMix = WetDryMix();
  const uint32 phase = Phase();
@@ -75,8 +75,8 @@ void Chorus::Process(float *pOutL, float *pOutR, uint32 numFrames)
  const float leftIn = *(in[0])++;
  const float rightIn = *(in[1])++;
 
- const int32 readOffset = GetBufferIntOffset(m_bufPos + m_delayOffset);
- const int32 writeOffset = GetBufferIntOffset(m_bufPos);
+ const int32 readOffset = GetBufferIntOffset(m_delayOffset);
+ const int32 writeOffset = m_bufPos;
  if(m_isFlanger)
  {
  m_DryBufferL[m_dryWritePos] = leftIn;
@@ -90,7 +90,7 @@ void Chorus::Process(float *pOutL, float *pOutR, uint32 numFrames)
 
  float waveMin;
  float waveMax;
- if(isTriangle)
+ if(isSquare)
  {
  m_waveShapeMin += m_waveShapeVal;
  m_waveShapeMax += m_waveShapeVal;
@@ -111,14 +111,14 @@ void Chorus::Process(float *pOutL, float *pOutR, uint32 numFrames)
  const float leftDelayIn = m_isFlanger ? m_DryBufferL[(m_dryWritePos + 2) % 3] : leftIn;
  const float rightDelayIn = m_isFlanger ? m_DryBufferR[(m_dryWritePos + 2) % 3] : rightIn;
 
- float left1 = m_bufferL[GetBufferIntOffset(m_bufPos + m_delayL)];
- float left2 = m_bufferL[GetBufferIntOffset(m_bufPos + m_delayL + 4096)];
+ float left1 = m_bufferL[GetBufferIntOffset(m_delayL)];
+ float left2 = m_bufferL[GetBufferIntOffset(m_delayL + 4096)];
  float fracPos = (m_delayL & 0xFFF) * (1.0f / 4096.0f);
  float leftOut = (left2 - left1) * fracPos + left1;
  *(out[0])++ = leftDelayIn + (leftOut - leftDelayIn) * wetDryMix;
 
- float right1 = bufferR[GetBufferIntOffset(m_bufPos + m_delayR)];
- float right2 = bufferR[GetBufferIntOffset(m_bufPos + m_delayR + 4096)];
+ float right1 = bufferR[GetBufferIntOffset(m_delayR)];
+ float right2 = bufferR[GetBufferIntOffset(m_delayR + 4096)];
  fracPos = (m_delayR & 0xFFF) * (1.0f / 4096.0f);
  float rightOut = (right2 - right1) * fracPos + right1;
  *(out[1])++ = rightDelayIn + (rightOut - rightDelayIn) * wetDryMix;
@@ -132,8 +132,8 @@ void Chorus::Process(float *pOutL, float *pOutR, uint32 numFrames)
  m_delayR = m_delayOffset + (phase < 2 ? -1 : 1) * static_cast<int32>(((phase % 2u) ? waveMax : waveMin) * m_depthDelay);
 
  if(m_bufPos <= 0)
- m_bufPos += m_bufSize * 4096;
- m_bufPos -= 4096;
+ m_bufPos += m_bufSize;
+ m_bufPos--;
  }
 
  ProcessMixOps(pOutL, pOutR, m_mixBuffer.GetOutputBuffer(0), m_mixBuffer.GetOutputBuffer(1), numFrames);
@@ -180,16 +180,16 @@ void Chorus::Resume()
 
  m_isResumed = true;
  m_waveShapeMin = 0.0f;
- m_waveShapeMax = IsTriangle() ? 0.5f : 1.0f;
+ m_waveShapeMax = IsSquare() ? 0.5f : 1.0f;
  m_delayL = m_delayR = m_delayOffset;
- m_bufPos = 0;
  m_dryWritePos = 0;
 }
 
 
 void Chorus::PositionChanged()
 {
  m_bufSize = Util::muldiv(m_SndFile.GetSampleRate(), 3840, 1000);
+ m_bufPos = 0;
  try
  {
  m_bufferL.assign(m_bufSize, 0.0f);
@@ -256,7 +256,7 @@ CString Chorus::GetParamDisplay(PlugParamIndex param)
  value = FrequencyInHertz();
  break;
  case kChorusWaveShape:
- return (value < 1) ? _T("Triangle") : _T("Sine");
+ return (value < 1) ? _T("Square") : _T("Sine");
  break;
  case kChorusPhase:
  switch(Phase())
@@ -290,7 +290,7 @@ void Chorus::RecalculateChorusParams()
  m_delayOffset = mpt::saturate_round<int32>(4096.0f * (delaySamples + 2.0f));
  m_frequency = FrequencyInHertz();
  const float frequencySamples = m_frequency / sampleRate;
- if(IsTriangle())
+ if(IsSquare())
  m_waveShapeVal = frequencySamples * 2.0f;
  else
  m_waveShapeVal = std::sin(frequencySamples * mpt::numbers::pi_v<float>) * 2.0f;

soundlib/plugins/dmo/Chorus.h

@@ -106,7 +106,7 @@ class Chorus : public IMixPlugin
  int32 GetBufferIntOffset(int32 fpOffset) const;
 
  virtual float WetDryMix() const { return m_param[kChorusWetDryMix]; }
- virtual bool IsTriangle() const { return m_param[kChorusWaveShape] < 1; }
+ virtual bool IsSquare() const { return m_param[kChorusWaveShape] < 1; }
  virtual float Depth() const { return m_param[kChorusDepth]; }
  virtual float Feedback() const { return -99.0f + m_param[kChorusFeedback] * 198.0f; }
  virtual float Delay() const { return m_param[kChorusDelay] * 20.0f; }

soundlib/plugins/dmo/Flanger.cpp

@@ -11,9 +11,9 @@
 #include "stdafx.h"
 
 #ifndef NO_PLUGINS
-#include "../../Sndfile.h"
 #include "Flanger.h"
-#endif // !NO_PLUGINS
+#include "../../Sndfile.h"
+#endif // !NO_PLUGINS
 
 OPENMPT_NAMESPACE_BEGIN
 

soundlib/plugins/dmo/Flanger.h

@@ -58,7 +58,7 @@ class Flanger final : public Chorus
 
 protected:
  float WetDryMix() const override { return m_param[kFlangerWetDryMix]; }
- bool IsTriangle() const override { return m_param[kFlangerWaveShape] < 1; }
+ bool IsSquare() const override { return m_param[kFlangerWaveShape] < 1; }
  float Depth() const override { return m_param[kFlangerDepth]; }
  float Feedback() const override { return -99.0f + m_param[kFlangerFeedback] * 198.0f; }
  float Delay() const override { return m_param[kFlangerDelay] * 4.0f; }