From 796c40a0dac68bd2bc9ccd676ad714f2fd3872fc Mon Sep 17 00:00:00 2001
From: Dominik Kaiser
Date: Mon, 6 Oct 2025 21:14:55 +0200
Subject: Add Decay

---
 src/DSP/CombFilter.cpp | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

(limited to 'src/DSP/CombFilter.cpp')

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;
-- 
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