init

Source/DSP/Compressor.h

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+#pragma once
+#include <cmath>
+#include <algorithm>
+
+class Compressor {
+public:
+    void prepare(double sr) {
+        sampleRate = sr;
+        envelope = 0.0f;
+    }
+
+    void setParameters(float thresholdDb, float ratio, float attackMs, float releaseMs,
+                       float makeupDb, float mix) {
+        threshold = std::pow(10.0f, thresholdDb / 20.0f);
+        compRatio = ratio;
+        attackCoeff = std::exp(-1.0f / (attackMs * 0.001f * static_cast<float>(sampleRate)));
+        releaseCoeff = std::exp(-1.0f / (releaseMs * 0.001f * static_cast<float>(sampleRate)));
+        makeupGain = std::pow(10.0f, makeupDb / 20.0f);
+        dryWet = mix;
+    }
+
+    float process(float input) {
+        float absIn = std::abs(input);
+        float coeff = (absIn > envelope) ? attackCoeff : releaseCoeff;
+        envelope = coeff * envelope + (1.0f - coeff) * absIn;
+
+        float gain = 1.0f;
+        if (envelope > threshold && compRatio > 1.0f) {
+            float overDb = 20.0f * std::log10(envelope / threshold);
+            float compressedDb = overDb / compRatio;
+            gain = std::pow(10.0f, (compressedDb - overDb) / 20.0f);
+        }
+
+        float wet = input * gain * makeupGain;
+        return input + (wet - input) * dryWet;
+    }
+
+private:
+    double sampleRate = 44100.0;
+    float threshold = 0.1f;
+    float compRatio = 4.0f;
+    float attackCoeff = 0.0f;
+    float releaseCoeff = 0.0f;
+    float makeupGain = 1.0f;
+    float dryWet = 1.0f;
+    float envelope = 0.0f;
+};