init

Source/DelayLine.h

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+#pragma once
+
+#include <algorithm>
+#include <cmath>
+#include <vector>
+
+namespace mindball
+{
+
+// Simple fractional-delay ring buffer with linear interpolation.
+class DelayLine
+{
+public:
+    void prepare (float maxDelaySamples)
+    {
+        maxDelay = std::max (1.0f, maxDelaySamples);
+        buffer.assign (static_cast<std::size_t> (maxDelay) + 2, 0.0f);
+        writePos = 0;
+    }
+
+    void clear()
+    {
+        std::fill (buffer.begin(), buffer.end(), 0.0f);
+        writePos = 0;
+    }
+
+    void write (float sample)
+    {
+        buffer[static_cast<std::size_t> (writePos)] = sample;
+        writePos = (writePos + 1) % static_cast<int> (buffer.size());
+    }
+
+    float read (float delaySamples) const
+    {
+        if (buffer.empty())
+            return 0.0f;
+
+        const float d = std::max (1.0f, std::min (delaySamples, maxDelay - 1.0f));
+        const int size = static_cast<int> (buffer.size());
+        const float readPos = static_cast<float> (writePos) - d;
+        const float floorPos = std::floor (readPos);
+
+        int i0 = static_cast<int> (floorPos) % size;
+        if (i0 < 0)
+            i0 += size;
+
+        const int i1 = (i0 + 1) % size;
+        const float frac = readPos - floorPos;
+        return buffer[static_cast<std::size_t> (i0)]
+             + (buffer[static_cast<std::size_t> (i1)] - buffer[static_cast<std::size_t> (i0)]) * frac;
+    }
+
+private:
+    std::vector<float> buffer;
+    float maxDelay = 1.0f;
+    int writePos = 0;
+};
+
+}