SimpleDelayPlugin/DelayPlugin.cpp at master · larzeitlin/SimpleDelayPlugin · GitHub

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#include "DelayPlugin.h"
#include "IPlug_include_in_plug_src.h"
#include "IControl.h"
#include "resource.h"

const int kNumPrograms = 1;

enum EParams
{
  kDelayMS,
  kFeedbackPC,
  kWetPC,
  kNumParams
};

enum ELayout
{
  kWidth = GUI_WIDTH,
  kHeight = GUI_HEIGHT,

  kGainX = 125,
  kGainY = 125,
  kKnobFrames = 60
};


DelayPlugin::DelayPlugin(IPlugInstanceInfo instanceInfo)
  :	IPLUG_CTOR(kNumParams, kNumPrograms, instanceInfo)
{
  TRACE;

  //arguments are: name, defaultVal, minVal, maxVal, step, label


  GetParam(kDelayMS)->InitDouble("Delay", 10., 0., 200., 0.01, "Milliseconds");
  GetParam(kFeedbackPC)->InitDouble("Feedback", 50., 0., 100.0, 0.01, "%");
  GetParam(kWetPC)->InitDouble("Wet/Dry", 50., 0., 100.0, 0.01, "%");


  IGraphics* pGraphics = MakeGraphics(this, kWidth, kHeight);

  pGraphics->AttachPanelBackground(&COLOR_GRAY);

  IBitmap* knob = pGraphics->LoadPointerToBitmap(KNOB_ID, KNOB_FN, kKnobFrames);

  pGraphics->AttachControl(new IKnobMultiControl(this, 20, 200, kDelayMS, knob));
  pGraphics->AttachControl(new IKnobMultiControl(this, 80, 200, kFeedbackPC, knob));
  pGraphics->AttachControl(new IKnobMultiControl(this, 140, 200, kWetPC, knob));

  AttachGraphics(pGraphics);

  //MakePreset("preset 1", ... );
  MakeDefaultPreset((char *) "-", kNumPrograms);
}

DelayPlugin::~DelayPlugin()
{
  if(mpBuffer)
  {
    delete [] mpBuffer;
  }
}

void DelayPlugin::ProcessDoubleReplacing(double** inputs, double** outputs, int nFrames)
{
  // Mutex is already locked for us.

  double* in1 = inputs[0];
  double* in2 = inputs[1];
  double* out1 = outputs[0];
  double* out2 = outputs[1];


  for (int s = 0; s < nFrames; ++s, ++in1, ++in2, ++out1, ++out2) // for loop to cycle through frame.
  {

    //first we read our delayed output
    double yn = mpBuffer[mReadIndex];


    //if the delay is 0 samples we just feed it the input
    if (mDelaySam == 0)
    {
      yn = *in1;
    }


    //now we write to out delay buffer

    mpBuffer[mWriteIndex] = *in1 + mFeedback * yn;


    //.. and then perform the calculation for the output. Notice how the *in is factored by 1 - mWet (which gives the dry level, since wet + dry = 1)
    *out1 =  ( mWet * yn + (1 - mWet) * *in1 );


    //then we increment the write index, wrapping if it goes out of bounds.
    ++mWriteIndex;
    if(mWriteIndex >= mBufferSize)
    {
      mWriteIndex = 0;
    }

    //same with thr read index
    ++mReadIndex;
    if(mReadIndex >= mBufferSize)
    {
      mReadIndex = 0;
    }

    //because we are working in mono we'll just copy the left output to the right output.
    *out2 = *out1;
  }
}

void DelayPlugin::Reset()
{
  TRACE;
  IMutexLock lock(this);

  mBufferSize = 2*GetSampleRate();
  if(mpBuffer)
  {
    delete [] mpBuffer;
  }

  mpBuffer = new double[mBufferSize];

  resetDelay();

  cookVars();
}

void DelayPlugin::resetDelay()
{
  if(mpBuffer)
  {
    memset(mpBuffer, 0, mBufferSize*sizeof(double));
  }

  mWriteIndex = 0;
  mReadIndex = 0;
}

void DelayPlugin::cookVars()
{
  mDelaySam = GetParam(kDelayMS)->Value() * GetSampleRate() / 1000.0;
  mFeedback = GetParam(kFeedbackPC)->Value() / 100.0;
  mWet = GetParam(kWetPC)->Value() / 100.0;

  mReadIndex = mWriteIndex - (int)mDelaySam;
  if(mReadIndex < 0)
  {
    mReadIndex += mBufferSize;
  }
}


void DelayPlugin::OnParamChange(int paramIdx)
{
  IMutexLock lock(this);
  cookVars();
}