From d4db11b195f70933ab4fda59d7d8becb2d06a4dd Mon Sep 17 00:00:00 2001
From: Armin <armin@cherry>
Date: Thu, 16 Jul 2026 00:21:14 +0200
Subject: [PATCH] Fix delay plucking with interpolated read tap

---
 Source/DSP/Delay.h | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/Source/DSP/Delay.h b/Source/DSP/Delay.h
index 5cfd08d..5f74946 100644
--- a/Source/DSP/Delay.h
+++ b/Source/DSP/Delay.h
@@ -14,9 +14,9 @@ public:
     }
 
     void setParameters(float timeMs, float fb, float mx) {
-        timeSamples = static_cast<int>(timeMs * 0.001f * sampleRate);
-        int bufMax = static_cast<int>(bufferL.size()) - 1;
-        timeSamples = std::clamp(timeSamples, 1, bufMax);
+        timeSamplesF = timeMs * 0.001f * static_cast<float>(sampleRate);
+        float bufMax = static_cast<float>(bufferL.size()) - 1.0f;
+        timeSamplesF = std::clamp(timeSamplesF, 1.0f, bufMax);
         feedback = std::clamp(fb, 0.0f, 0.95f);
         mix = std::clamp(mx, 0.0f, 1.0f);
     }
@@ -24,10 +24,15 @@ public:
     void process(float& left, float& right) {
         int bufSize = static_cast<int>(bufferL.size());
 
-        int readPos = (writePos - timeSamples + bufSize) % bufSize;
+        float readPosF = static_cast<float>(writePos) - timeSamplesF;
+        while (readPosF < 0.0f) readPosF += static_cast<float>(bufSize);
 
-        float outL = bufferL[readPos];
-        float outR = bufferR[readPos];
+        int i0 = static_cast<int>(readPosF) % bufSize;
+        int i1 = (i0 + 1) % bufSize;
+        float frac = readPosF - std::floor(readPosF);
+
+        float outL = bufferL[i0] * (1.0f - frac) + bufferL[i1] * frac;
+        float outR = bufferR[i0] * (1.0f - frac) + bufferR[i1] * frac;
 
         bufferL[writePos] = left + outL * feedback;
         bufferR[writePos] = right + outR * feedback;
@@ -42,7 +47,7 @@ private:
     std::vector<float> bufferL, bufferR;
     int writePos = 0;
     double sampleRate = 44100;
-    int timeSamples = 8820;
+    float timeSamplesF = 8820.0f;
     float feedback = 0.3f;
     float mix = 0.25f;
 };