Add Decay

6 files changed, 33 insertions, 26 deletions

diff --git a/src/DSP/CombFilter.cpp b/src/DSP/CombFilter.cpp
index 0ee03fc..5ee8efc 100644
--- a/src/DSP/CombFilter.cpp
+++ b/src/DSP/CombFilter.cpp
@@ -1,7 +1,7 @@
 #include "CombFilter.h"
 
 void
-CombFilter::prepare(double sampleRate, int samplesPerBlock, int delayInSamples, float gain)
+CombFilter::prepare(double sampleRate, int samplesPerBlock, int delayInSamples)
 {
     int maxDelayTimeMs = 50;
     int maxDelaySamples = static_cast<int>(sampleRate * maxDelayTimeMs / 1000.0);
@@ -9,17 +9,19 @@ CombFilter::prepare(double sampleRate, int samplesPerBlock, int delayInSamples,
     delayBuffer.resize(maxDelaySamples, 0.0f);
     std::fill(delayBuffer.begin(), delayBuffer.end(), 0.0f);
     delayBufferWritePos = 0;
+    this->sampleRate = sampleRate;
     this->delayInSamples = delayInSamples;
-    this->gain = gain;
 }
 
 void
-CombFilter::process(float& sample)
-{
+CombFilter::process(float& sample, float decayFactor)
+{    
     int delayBufferLength = (int)delayBuffer.size();
     int delayReadPos
         = (delayBufferWritePos - delayInSamples + delayBufferLength) % delayBufferLength;
     float delayedSample = delayBuffer[delayReadPos];
+
+    float gain = std::pow(10.0f, -3.0f * delayInSamples / (decayFactor * sampleRate));
     
     delayBuffer[delayBufferWritePos] = sample + gain * delayedSample;
     sample = delayedSample;
diff --git a/src/DSP/CombFilter.h b/src/DSP/CombFilter.h
index 6eada89..eb5e914 100644
--- a/src/DSP/CombFilter.h
+++ b/src/DSP/CombFilter.h
@@ -5,13 +5,13 @@
 class CombFilter
 {
   public:
-    void prepare(double sampleRate, int samplesPerBlock, int delayInSamples, float gain);
+    void prepare(double sampleRate, int samplesPerBlock, int delayInSamples);
     void reset();
-    void process(float& sample);
+    void process(float& sample, float decayFactor);
 
   private:
     std::vector<float> delayBuffer;
     int delayBufferWritePos = 0;
+    double sampleRate = 0.0;
     int delayInSamples = 0;
-    float gain = 0.7f;
 };
diff --git a/src/DSP/SchroederReverb.cpp b/src/DSP/SchroederReverb.cpp
index 97406d2..1b84712 100644
--- a/src/DSP/SchroederReverb.cpp
+++ b/src/DSP/SchroederReverb.cpp
@@ -3,30 +3,34 @@
 void
 SchroederReverb::prepare(double sampleRate, int samplesPerBlock)
 {
-    combFilter0.prepare(sampleRate, samplesPerBlock, 1557, 0.742f);
-    combFilter1.prepare(sampleRate, samplesPerBlock, 1613, 0.733f);
-    combFilter2.prepare(sampleRate, samplesPerBlock, 1499, 0.715f);
-    combFilter3.prepare(sampleRate, samplesPerBlock, 1427, 0.697f);
+    preDelay.prepare(sampleRate, samplesPerBlock);
+    combFilter0.prepare(sampleRate, samplesPerBlock, 1557);
+    combFilter1.prepare(sampleRate, samplesPerBlock, 1613);
+    combFilter2.prepare(sampleRate, samplesPerBlock, 1499);
+    combFilter3.prepare(sampleRate, samplesPerBlock, 1427);
     allPassFilter0.prepare(sampleRate, samplesPerBlock, 347, 0.7f);
     allPassFilter1.prepare(sampleRate, samplesPerBlock, 1137, 0.7f);
 }
 
 void
-SchroederReverb::process(float& sample, float dryWetMix)
+SchroederReverb::process(float& sample, float dryWetMix, float decayFactor)
 {
     juce::ScopedNoDenormals noDenormals;
 
-    float in0 = sample;
-    float in1 = sample;
-    float in2 = sample;
-    float in3 = sample;
+    float in = sample;
 
-    combFilter0.process(in0);
-    combFilter1.process(in1);
-    combFilter2.process(in2);
-    combFilter3.process(in3);
 
-    float allPassIn = 0.25f * (in0 + in1 + in2 + in3);
+    float cf0in = in;
+    float cf1in = in;
+    float cf2in = in;
+    float cf3in = in;
+
+    combFilter0.process(cf0in, decayFactor);
+    combFilter1.process(cf1in, decayFactor);
+    combFilter2.process(cf2in, decayFactor);
+    combFilter3.process(cf3in, decayFactor);
+
+    float allPassIn = 0.25f * (cf0in + cf1in + cf2in + cf3in);
     allPassFilter0.process(allPassIn);
     allPassFilter1.process(allPassIn);
 
diff --git a/src/DSP/SchroederReverb.h b/src/DSP/SchroederReverb.h
index c6e5110..2d5cd0b 100644
--- a/src/DSP/SchroederReverb.h
+++ b/src/DSP/SchroederReverb.h
@@ -9,7 +9,7 @@ class SchroederReverb
   public:
     void prepare(double sampleRate, int samplesPerBlock);
     void reset();
-    void process(float& sample, float dryWetMix);
+    void process(float& sample, float dryWetMix, float decayFactor);
 
   private:
     CombFilter combFilter0, combFilter1, combFilter2, combFilter3;
diff --git a/src/PluginProcessor.cpp b/src/PluginProcessor.cpp
index 770f7a2..f10065f 100644
--- a/src/PluginProcessor.cpp
+++ b/src/PluginProcessor.cpp
@@ -7,7 +7,8 @@ SchroederReverbAudioProcessor::SchroederReverbAudioProcessor()
                          .withInput("Input", juce::AudioChannelSet::stereo(), true)
                          .withOutput("Output", juce::AudioChannelSet::stereo(), true))
 {
-    addParameter(dryWetMix = new juce::AudioParameterFloat({ "mix", 1 }, "Mix", 0.0f, 1.0f, 0.5f));
+    addParameter(dryWetMix = new juce::AudioParameterFloat("mix", "Mix", 0.0f, 1.0f, 0.5f));
+    addParameter(decayFactor = new juce::AudioParameterFloat("decay", "Decay", 0.1f, 10.0f, 1.0f));
 }
 
 SchroederReverbAudioProcessor::~SchroederReverbAudioProcessor() {}
@@ -40,8 +41,7 @@ SchroederReverbAudioProcessor::isMidiEffect() const
 double
 SchroederReverbAudioProcessor::getTailLengthSeconds() const
 {
-    // TODO: Change number after implementing Decay
-    return 0.0;
+    return 10.0;
 }
 
 int
@@ -114,7 +114,7 @@ SchroederReverbAudioProcessor::processBlock(juce::AudioBuffer<float>& buffer,
         for (int i = 0; i < buffer.getNumSamples(); ++i)
         {
             // Apply effect to sample
-            schroederReverb.process(channelData[i], dryWetMix->get());
+            schroederReverb.process(channelData[i], dryWetMix->get(), decayFactor->get());
         }
     }
 }
diff --git a/src/PluginProcessor.h b/src/PluginProcessor.h
index 27203ca..f6e6f5d 100644
--- a/src/PluginProcessor.h
+++ b/src/PluginProcessor.h
@@ -49,5 +49,6 @@ class SchroederReverbAudioProcessor final : public juce::AudioProcessor
     //==============================================================================
     SchroederReverb schroederReverb;
     juce::AudioParameterFloat* dryWetMix;
+    juce::AudioParameterFloat* decayFactor;
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(SchroederReverbAudioProcessor)
 };